Mid-Infrared Nonlinear Optical Materials Based on Metal

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Review

Mid-infrared nonlinear optical materials based on metal chalcogenides: structure-property relationship Fei Liang, Lei Kang, Zheshuai Lin, and Yicheng Wu Cryst. Growth Des., Just Accepted Manuscript • DOI: 10.1021/acs.cgd.7b00214 • Publication Date (Web): 15 Mar 2017 Downloaded from http://pubs.acs.org on March 18, 2017

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Crystal Growth & Design

Mid-infrared nonlinear optical materials based chalcogenides: structure-property relationship

on

metal

Fei Liang, †,‡ Lei Kang, †,‡ Zheshuai Lin, *,†,‡ Yicheng Wu † † Center for Crystal R&D, Key Lab Functional Crystals and Laser Technology of Chinese Academy of Sciences, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, PR China. ‡ University of Chinese Academy of Sciences, Beijing 100190, PR China KEYWORDS. Mid-IR nonlinear optics, metal chalcogenides, structure-property relationship ABSTRACT: Mid-infrared (IR) nonlinear optical (NLO) materials with high performance are vital to expanding the laser wavelengths into the mid-IR region, and have important technological applications in many civil and military fields. For the last two decades metal chalcogenides have attracted great attentions since many of them possess large NLO effect, wide transparent range, moderate birefringence and high resistance to laser damage. However, the discovery of superior mid-IR NLO metal chalcogenides is still a big challenge mainly attributed to the difficulty of achieving the good balance between NLO effect and laser damage threshold (LDT). In this review, the metal chalcogenides are catalogued according to the different types of microscopic building blocks. These groups include triangle planar units, tetrahedral metal-centered unit, polyhedra with second-order John-Teller (SOJT) cations, and polyhedra with stereochemically active lone electron pairs (SALP) cations, rare-earth (RE) cations and/or halogen anions. The determinations of these microscopic structures on mid-IR NLO properties in metal chalcogenides are summarized and analyzed combined with available experimental data and first-principle calculations. From the deduced structure-property relationship, the searching directions for new metal chalcogenides that have good mid-IR NLO performances, especially for achieving the balance between large NLO effect and high LDT, are discussed. transparent region, which is able to run across two 1. Introduction important atmospheric transparent windows of 3 – 5 µm Nonlinear optical (NLO) materials are of great and 8 – 12 µm. (ii) large second harmonic generation (SHG) importance for converting the laser wavelengths to the spectral regions where the normal lasers operate poorly.1 In coefficient dij, which should be at least larger than 10 × KDP the past three decades, many useful NLO crystals in near-IR, (d36 ~ 0.39 pm/V), and at best larger than 1 × AGS (d36 ~ 13 visible and ultraviolet regions (wavelength from 0.2 to 2 µm) pm/V); (iii) High laser damage threshold (LDT), which have been developed, such as β-BaB2O4 (β-BBO),2 LiB3O5 depends on the bandgap (Eg) of materials intrinsically. For a (LBO),3 LiNbO3 (LN),4 KH2PO4 (KDP),5 KTiOPO4 (KTP).6 good mid-IR NLO material, the bandgap Eg should be more These crystals are widely used in scientific and technological than 3.0 eV. (iv) Moderate birefringence ∆n (~ 0.03 – 0.10), fields, including visible laser generation,7 artificial nuclear in order to achieve the phase-matching condition in fusion,8 precision scientific instruments9 and so on. frequency conversion process with such as optical However, the NLO materials which can efficiently generate parametric oscillation (OPO) and optical parametric the high-power mid-IR lasers in the spectral range of 2–25 amplification (OPA). (v) Good crystal growth habit and μm are very scarce. In fact, the mid-IR lasers have chemical stability, which is definitely beneficial to the significant applications in many military and civil activities, practical applications of mid-IR NLO crystal. It should be such as remote sensing,10 biological tissue visualization,11 emphasized that the balance between SHG coefficients and environmental monitoring12 and anti-terror security.13 bandgap is the key factor to achieve the good optical So far, the commercially available mid-IR NLO crystals performance in a mid-IR NLO crystal, since an increase of are AgGaS2 (AGS), AgGaSe2 (AGSe) and ZnGeP2 (ZGP).14 Eg would result in the decrease of dij.18 They possess high SHG coefficients of about 13 pm/V, 33 In fact, it is difficult to find a material that can satisfy the pm/V, and 75 pm/V, respectively.14 Despite of large NLO above conditions simultaneously. Generally, NLO oxide coefficient and good grow habit, these materials have materials are unsuitable for broad IR applications because drawbacks which hinder their application in mid-IR lasers of their relatively short IR absorption wavelength. For generation. For example, the LDT value of AGS and AGSe is example, KTP, LN, LiIO3, BaTeMo2O9 crystals are too small (only about 25 MW/cm2 and 11 MW/cm2, (@1.06 transparent to 4.5 µm, 5.2 µm, 6.0 µm and 5.4 µm,15, 19 µm, 35 ns)15, respectively) to bear high power pumping respectively. They can only cover the first atmospheric source. Meanwhile, the strong two-photon adsorption (TPA) transparent window (3 – 5 µm) and exhibit strong lattice in ZGP resulted from its narrow bandgap (2.0 eV) make it vibration adsorption due to photon-phonon interaction. impossible to use Nd:YAG 1064 nm laser as pumping Organic NLO crystals have giant nonlinear optical source.16 Thus, the currently rapid developments of mid-IR coefficient,20 but its stability is relatively poor. Many organic lasers urgently demand the discovery of new mid-IR NLO NLO crystals denature or even decompose under the materials with good performance. temperature of 300-400 K.20-22 In addition, this type of In general, practically usable mid-IR NLO materials NLO crystals are usually deliquescent and soluble in water, should satisfy the following conditions:17 (i) Broad mid-IR and the examples include famous DAST and DSTMS.23-24

ACS Paragon Plus Environment


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Halides are a type of promising sources for good IR NLO materials since they often have large bandgaps (high LDT) and excellent IR transparency. For instance, NaSb3F10 crystal has a large bandgap 5.0 eV and its laser damage threshold is as high as about 1.3 GW/cm2.25 It also shows excellent transparency in the range of 0.25–7.8 µm with relativity high thermal stability. In addition, the LDT of CsGeCl3,26 HgBr227 and Rb2CdBr2I228 can reach 200 MW/cm2, 300 MW/cm2, 190 MW/cm2, respectively, which is much larger than that of AGS (25 MW/cm2) and AGSe (11 MW/cm2). Meanwhile, these three materials are transparent up to 30 µm, 20 µm and 14 µm,27-29 covering the two atmospheric transparent windows. However, the SHG coefficients of halides are generally much smaller compared with AGS. As reported in literature, NaSb3F10,25 HgBr227 and Rb2CdBr2I228 exhibit a phase-matchable SHG efficiency of only about 3.2, 10.0 and 4.0 times that of KDP, respectively. The mechanism analysis has revealed that the large bandgaps of halides are mainly resulted from the strong ionic characteristic of halogen atom, which are usually unfavorable to the acquirement of large SHG coefficient dij.30 In spite of this, it still would be a good strategy to introduce the halogen atoms into oxides or chalcogenides, thus improving the LDT of compounds while maintaining a large enough SHG coefficient, as like in RbIO2F31 and NaBa4Ge3S10Cl.32 Phosphides are also a promising IR NLO material system due to their large SHG coefficient and moderate birefringence. For example, ZnGeP233 crystal has a large SHG coefficient d33 (75 pm/V) and wide transparent region from 0.74 to 12 µm. Moreover, as the Zn and Ge atoms in ZnGeP2 are replaced by Cd and Si atoms, one may obtain another good IR NLO crystal, CdSiP2.34 This compound has a slightly larger SHG coefficient (d33=84.5 pm/V) than ZnGeP2 and avoids the TPA drawback at 1064 nm due to its relatively large bandgap of 2.45 eV. Unfortunately, CdSiP2 crystal is only transparent up to 9 µm due to the vibration absorption of Si-P bond, so it can not entirely cover the second atmospheric transparent window (8 – 12 µm).35 In addition, it is difficult to grow large size CdSiP2 crystal because quartz tube is easy to explode during crystal grow process.36 Recently, some research groups have discovered a plenty of metal chalcogenides which exhibit good IR NLO response, including BaGa4S7,37 BaGa4Se7,38 Li2Ga2GeS6,39-40 LiGaGe2Se6,41-42 BaGa2GeS6,43-44 BaGa2GeSe6,43-44 KPSe6,45-49 K2P2Se6,50 Ba23Ga8Sb2S38,51 γ-NaAsSe2,52 Na2Ge2Se5,53 LiAsS2,54 K3Ta2AsS11,55 K4GeP4Se12,56-57 La4InSbS9,58 Ba2BiInS5,59 K2Hg3Ge2S8,60 Li2CdGeS4,61-63 Na2ZnGe2S6,64 ACd4Ga5S12 (A=K, Rb, Cs),65 Ba3AGa5Se10Cl2 (A=K, Rb, Cs),66 [A3X][Ga3PS8] (A=K, Rb; X=Cl, Br)67 and so on. Among these materials, KPSe6, γ-NaAsSe2 and Na2Ge2Se5 exhibit the highest SHG coefficient ever reported in inorganic materials with calculated dij=75, 162 and 145 pm/V, respectively.68 Unfortunately, these three materials have small bandgap below 2.5 eV, which would cause a low LDT in laser frequency conversion. In addition, ACd4Ga5S1265 and Ba3AGa5Se10Cl266 (A=K, Rb, Cs) showed a high SHG efficiency, 22 and 10 times larger than that of AGS, respectively. However, their birefringence is too small to achieve phase-match under 2.05 µm fundamental laser. So they are not suitable for mid-IR laser generation by angle-phase-match technique. Some of other chalcogenides are also plagued by the same disadvantages, including Ba23Ga8Sb2S3851 and A3Ta2AsS11 (A=K, Rb).55 Therefore, it is still a challenge to find a superior NLO material that satisfies a good balance between high LDT and large NLO

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effect, as well as moderate birefringence, chemical stability and ease in the growth of large high-quality single crystals. In spite of the situations listed above, through comprehensive surveys we find that the metal chalcogenides are still the most suitable system for mid-IR NLO crystal because they have the capability to achieve the balance between LDT (intrinsically relies on bandgap) and SHG response as good as possible. For example, BaGa4S7 has large bandgap 3.65 eV as well as high SHG coefficients (d33=12.6 pm/V).37 The bandgap of BaGa2GeS6 exceeds 3.0 eV and its NLO response is 2.1 times of AGS under 2.05 µm irradiation.44 Moreover, in metal chalcogenides the connected patterns of anionic groups display a great structural diversity. The zero-dimensional (0-D) discrete clusters, one-dimensional (1-D) chains, two-dimensional (2-D) layers, and three-dimensional (3-D) frameworks can be constructed. Thus, this family actually provides a huge reservoir for good mid-IR NLO material searching. In 2014, Chung and Kanatzidis wrote an excellent review from the viewpoint of different structure dimensions and cover many metal chalcogenide compounds which are SHG active.68 It has highlighted that the metal chalcogenides show rich structural and compositional diversity, excellent IR transparency and good NLO performances. In addition, they discussed a new concept to fabricate fibers, thin films and bulk glasses based on different dimensional structures. It is well known that non-centrosymmetric (NCS) structure is the prerequisite for a SHG material. In this review, different with Chung and Kanatzidis’ viewpoint, we will focus on more microscopic NCS building units in the metal chalcogenides discovered in this decade, and investigate the A-B-C-Q(-X) system (A = Ag+, Cu+, alkaline metal, alkaline earth metal and rare earth cations; B = As3+, Bi3+, Sb3+, Pb2+, Sn2+, ,Te4+, Te2+, Ti4+, Zn2+,Cd2+, Hg2+ etc.; C = Al3+, Ga3+, In3+, Ge4+,Si4+,Sn4+, P5+ etc.; Q= S2-, Se2-, Te2-; and X=F-, Cl-, Br-, I-). In details, the microscopic NCS groups include: (i) triangle-planar anionic groups (such as [BS3]3-, [B3S6]3-, [HgSe3]4-); (ii) distorted polyhedra centered by stereochemically active lone pairs (SALP) cation, including As3+, Sb3+, Bi3+, Sn2+, Pb2+, Te4+/Te2+ and so on; (iii) distorted polyhedra centered by second-order Jahn-Teller (SOJT) effect d0 or d10 cation; (iv) rare-earth cations centered polyhedra, mainly including La3+, Ce3+, Pr3+, Nd3+, etc; (v) main group elements centered [MQ4] (M=XII, XIII, XIV, XV) tetrahedra in crystal structures. We will analyze the structure-property relationship in these metal chalcogenides from the available experimental and first-principles data. For some metal chalcogenides whose linear and nonlinear optical properties have not been deeply investigated, the first-principles predictions are performed by our developed computational methods69 based on the density functional theory (DFT) package CASTEP.70 Our previous work has demonstrated that these computational methods have the capability to obtain the accurate results in metal chalcogenides.17 In addition, some hypothetical materials are predicted through composition substitution or structural transformation. The stability of hypothetical materials are examined by phonon spectrum analysis.71 We believe this review, combined with Chung and Kanatzidis’, will give a more comprehensive insight on this type of important optoelectronic functional materials. 2. Metal chalcogenides containing various NCS SHG active units 2.1 Metal chalcogenides containing triangle-planar anionic units 2.1.1 Metal chalcogenides containing triangle planar π-conjugated units


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As well known, in the UV and DUV spectral regions the mostly used NLO materials are borates in which the SHG active units are planar sp2 hybridized [BO3]3- triangles or [B3O6]3- groups.72-74 The planar boron-oxygen groups can generate the relatively strong second-order susceptibility owing to its distinctive π-conjugated electron orbitals. Meanwhile, the [BO3]3- group can have large energy bandgaps (or high LDT values) as the electronic orbitals on termined oxygen atoms are saturated.75 Analogously, [BS3]3and [B3S6]3- planar trigonal building units are the common structural motifs having large microscopic SHG responses, since the π-conjugated electrons delocalized on the plane are very susceptible to the applied optoelectric field. So thioborates are thought to be a possible family that combines the favorable transparency and nonlinearity of sulfides with the high damage thresholds of borates. In addition, planar units are favourable to obtain large birefringence. Up to now, there are three typical types of NCS thioborates ever known, i.e. LiBaB3S6, BaB2S4 and Ba3(BS3)(SbS3). LiBaB3S6 LiBaB3S6 crystallizes in the NCS monoclinic Cc space group.76 It contains [B3S6]3- anions formed by six-membered [B3S3] rings with three exocyclic sulfur atoms (Figure 1a). The metal cations are situated between the anion units leading to nine-fold sulfur coordination of the Ba2+ and four-fold coordination of the Li+. Our calculations demonstrate that LiBaB3S6 is a possible mid-IR NLO material owing to its large bandgap (3.92 eV), thus indicating a high LDT value. The birefringence is 0.343 at 1064 nm, which is favourable for achieving phase-match condition. However, the SHG coefficients are rather small owing to approximately centrosymmetric arrangement of [B3S6]3- units. BaB2S4 BaB2S4 crystallizes in monoclinic space group Cc and contains [BS3]3- and [BS4]5- units in the ratio 1:1 forming infinite chains along [001] direction.77 Ba2+ cations are located between chains leading to ten-fold sulfur coordination (Figure 1b). Our calculations show that BaB2S4 have a large bandgap more than 3.5 eV and maximum SHG coefficients d12 close to 0.6×AGS, which satisfies a good balance between bandgap and SHG effect. Further analysis reveals that although [BS3]3- and [BS4]5units are both contributing to the SHG effect of BaB2S4, the former groups make the dominant contributions. Ba3(BS3)(SbS3) Ba3(BS3)(SbS3) compound features a 0D structure constructed by isolated [BS3]3- trigonal planes and discrete [SbS3]3- pyramids (Figure 1c).78 Every two isolated [SbS3]3− pyramids along the c axis are anti-aligned, so they have less contribution to SHG effect. The Ba2+ cations exhibit typical eight- or nine-fold coordination. Ba3(BS3)(SbS3) has moderate direct bandgap 2.62 eV and is almost transparent in the range of 2.5−11 µm.78 A strong absorption band in the infrared spectra and weak absorption bands in the Raman spectra from 800 to 900 cm−1 (around 11.8−12.5 µm) are assigned to the stretching vibrational modes of [BS3] group. The calculated static birefringence of Ba3(BS3)(SbS3) is 0.05, which is close to that of AGS (0.039), indicating that it can achieve phase-matchable.78 Ba3(BS3)(SbS3) exhibits the strong SHG efficiency about three times as large as that of AGS under same condition.

Figure 1. Crystal structure of (a) LiBaB3S6 (b) BaB2S4 and (c) Ba3(BS3)(SbS3) It seems that the π-conjugated [BS3]3- group is suitable to be a good fundamental building block for mid-IR NLO materials. However, in contrast to stable [BO3]3- groups, the [BS3]3- groups are very sensitive to air and humidity and not stable even under ambient environment.79 This actually suggests that thioborates might be practically applied as good mid-IR NLO materials if the problem of chemical stability could be overcome. 2.1.2 Metal chalcogenides containing d10 cation centered [MQ3] units In addition to the sp2 hybridized [BS3]3-, d10 cations centered trigonal planar units are sometimes seen in metal complexes, such as [AgS3]7- in La3AgSnS7,80 [CuS3]7- in La3CuGeS7,81 [ZnSe3]4- in Hg3ZnSe3Br2,82 and [HgSe3]4- in BaHgSe2.83 Here, we take BaHgSe2 as a representative example to show the structure and NLO properties in this type of metal chalcogenides. BaHgSe2 BaHgSe2 belongs to the orthorhombic NCS space group Pmc21.83 It contains corner-sharing [Hg(1)Se3]4- trigonal planar structural units (Figure 2a) and isolated [Hg(2)Se2]2- linear structural units (Figure 2b). The [Hg(1)Se3]4- triangles are aligned parallel to each other within an individual chain along the a-axis, but neighboring chains are tilted with respect to each other (Figure 2c), which may not be ideal for NLO performance. However, the compound still exhibit a large SHG response, which is about 1.5 times that of AGS with similar particle size under 2.09 µm fundamental light.83 Our first-principles calculations reveal that the largest SHG coefficient d33 is 39.87 pm/V, and the contribution is mainly from [Hg(1)Se3]4- triangles (79%). More importantly, BaHgSe2 melts congruently at a rather low temperature of 638°C, which is valuable for the growth of bulk single crystals by the Bridgman-Stockbarger technique.83 So, the study of BaHgSe2 demonstrates that [HgSe3]4- triangles can serve as a new kind of basic functional units in mid-IR NLO materials. The incorporation of triangle planar units may



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lead to the discovery of a new class of practically applicable mid-IR NLO materials.

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Table 1 lists the experimental and calculated linear and nonlinear optical properties in the metal chalcogenides compounds containing the planar [MQ3] units. Clearly, these compounds possess large birefringence (> 0.05) owing to strong anisotropy of planar units. A large net polarization would obtain when the microscopic susceptibility don’t cancel out. In particular, d10 cations centered planar units may be a potential direction for exploration of new mid-IR NLO materials.

Figure 2. The coordination environment of (a) triangle planar [Hg(1)Se3]4-, (b) linear [Hg(2)Se2]2- and (c) crystal structure of BaHgSe2. Reprinted with permission from ref [83], Copyright 2016 American Chemical Society. Table 1. Experimental and calculated Eg, dij, and ∆n in the metal chalcogenides compounds containing [MQ3] planar units. compounds Space Eg SHG efficiency calculated dij (pm/V) ∆n (cal) group (eV) LiBaB3S676 Cc 3.92a No data d11=-3.18;d12=3.46; 0.343 (@1064nm) d23=-2.98;d33=0.96 (static) BaB2S477 Cc 3.61a No data d12=7.16;d13=-6.18; 0.068 (@1064nm) d23=-3.47;d33=0.79 (static) Ba3(BS3)(SbS3)78 P-62m 2.62 d21=-d22=2.73(@2050 nm) 0.050 (static) 3.0×AGS (@2050nm,30-46µm) Zn0.2Ba2B2S5.284

I-42m

3.54

50×SiO2 (@1064nm,45-63µm)

-

-

BaHgSe283

Pmc21

1.56

1.5×AGS (@2090nm,105-150µm)

d33=39.87;dpowder=26.54 (static)

0.147 (@1064nm)

a

calculated bandgap by DFT methods

2.2 Metal chalcogenides containing SALP cations centered units Generally, in As3+, Sb3+, Bi3+, Sn2+, Pb2+ and Te4+/Te2+ the s2 electrons on the outermost electronic shell are not shared with another ions, and form the lone-pair electrons. Under external optoelectric field interaction, they could exhibit a very large second-order optical response. Therefore, the compounds containing the cations with lone-pair electrons provide good platforms for searching new IR materials with giant SHG effect. Up to now, many compounds in this type of mid-IR NLO metal chalcogenides have been discovered. In this section, we choose some representative metal chalcogenides in which the cations with lone pairs electrons locate in low-coordination environments (so forming SALP cations), and summarize their experimental linear and nonlinear properties. LiAsS2 type LiAsS2 crystallizes in the polar space group Cc.54 It features a 1D infinite [AsS2]- chains along the c axis, which are made of condensed trigonal pyramidal units [AsS3]3-. Every corner-sharing [AsS3]3- trigonal pyramids have two different sulfur atoms: a bridging atom S(2) and a terminal atom S(1) (Figure 3), thus the SALP 4s2 electrons on As atoms will be superposed along the c axis. The NCS structure of Li1-xNaxAsS2 holds stable up to 40% Na+ doping. A further increase in the Na fraction leads to a structural transition from NCS Cc to CS Pbca space group. The SHG intensity of LiAsS2 and Li0.6Na0.4AsS2 is 10 and 30 times that of AGSe at 790 nm, respectively.54 Unluckily, the bandgap of LiAsS2 is only 1.60 eV, comparable to AGSe (1.80 eV), which is too small to bear high-power pumping laser source. Furthermore, powder SHG measurement indicated that it is not type-I phase-matchable in the examined spectral region,54 resulting in the difficulty of achieving noticeable SHG output.

Figure 3. Crystal structure of (a) NCS LiAsS2 (b) CS NaAsS2, (c) a signal 1D infinite [AsS2]- chains. White balls: Li/Na; red balls: As; yellow balls: S. Adapted and reprinted with permission from ref [54], Copyright 2008 John Wiley & Sons Inc. β-LiAsSe2 and γ-NaAsSe2 type AAsSe2 (A=Li, Na) have been identified as a new class of polar direct-band gap semiconductors.52 They consist of infinite single chains of [AsSe2]- derived from corner-sharing pyramidal [AsSe3]3units with SALP electrons on As atoms. β-LiAsSe2 crystallizes in the NCS space group Cc and is isostructural with LiAsS2 (Figure 4a). The [AsSe3]3pyramid provides the molecular building units in the zweier single chain via corner bridging (Figure 4e). In comparison, γ-NaAsSe2 crystallizes in the NCS space group Pc. The structure consists of densely packed parallel


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[AsSe2]- polymeric anionic chains and Na+ ions (Figure 4b and 4c). Interestingly, the [AsSe2]- polymeric anionic chains in γ-NaAsSe2 is different with that in β-LiAsSe2. This new vierer single chain (Figure 4f) conformation preserves the NCS structure with higher Na+ substitution in the Li1-xNaxAsSe2 system in comparison to the Li1-xNaxAsS2 system, where only 40% Na substitution with preservation of the NCS structure. The fully Na substituted phase in the Li1-xNaxAsSe2 system was found to adopt two structural forms γ-NaAsSe2 and δ-NaAsSe2 (Figure 4d). First-principles calculations and experiments showed there is a very small energy difference between the γ and δ polymorph, and the former is the thermodynamically stable phase.52 The energy band gaps of these compounds are located in 1.11−1.75 eV, depending on the structure type and composition. In the wavelength range of 700−900 nm, SHG effects of β-Li0.2Na0.8AsSe2, γ-Li0.2Na0.8AsSe2, and γ-NaAsSe2 are ∼55, 65, and 75 times stronger than that of AGSe, respectively.52 The values are huge, especially for the Na-rich compounds. As pointed by M.G. Kanatzidis, besides the strong SALP electrons on [AsSe3]3- units, the decrease in dimensionality with the more substitution of larger size Na+ ion is responsible for the higher SHG efficiency of the Na-rich compounds.52 As the Na+ ions substitute for Li+, the [AsSe2]- chains are increasingly separated apart from one another and inter-chain interactions are weakened, thereby lowering the dimensionality of the system. The DFT calculated d33 value for γ-NaAsSe2 is 162.3 pm/V,85 which is the highest static SHG coefficient to date among the materials with bandgaps more than 1.0 eV. Particle size dependent SHG measurements indicated that all three materials are non-phasematchable at 790 nm.52

Figure 4. Crystal structure of (a) β-LiAsSe2, (b) γ-NaAsSe2 viewed down the a-axis, (c) γ-NaAsSe2 viewed down the b-axis and (d) δ-NaAsSe2 (e) the zweier chain in β-LiAsSe2 (f) the vierer single chain in γ-NaAsSe2. White balls: Li/Na; cyan balls: As; red balls: Se. Adapted and reprinted with permission from ref [52], Copyright 2010 American Chemical Society. Ag3MS3 (M=As/Sb) The proustite Ag3AsS3 and Ag3SbS3 are natural mineral species and crystallizes in trigonal R3c space group.86-87 We select Ag3AsS3 as an example to describe the crystal structure. Each As atom is coordinated by three S atoms, forming a trigonal pyramid [AsS3]3- units (Figure 5a) and each Ag+ ion adopts an unsymmetrical T-shaped geometry [AgS3]5- (Figure 5c). The T-shaped [AgS3]5- units are connected via corners to give two sets of

helical chain [AgS2]3− along the c axis. These chains are further interconnected via the bridging S atoms leading to a 3D network. The polar character of Ag3AsS3 and Ag3SbS3 are the result of the combination of unsymmetric helical chains [AgS2]3− and trigonal [AsS3]3-/[SbS3]3- pyramids with SALP electrons. Kurtz-Perry measurement demonstrates that Ag3AsS3 powders display SHG response about 1.1 times that of AGS, which is consistent with SHG coefficients (d31=10.4 pm/V).87 It shows a very steep and strong absorption edge at 2.03 eV, which is smaller than AGS (2.78 eV). The IR spectrum shows a good transmittance between 2.5−12.5 µm, except a strong absorption band at 1600 cm-1 because of As-S bond vibration.87 Therefore, Ag3AsS3 is a promising mid-IR NLO material. It has been used in SHG of CO2 laser as well as sum-frequency generation (SFG) of between CO2 and He-Ne lasers in 1970s.88 However, its LDT value is too small, only 12 MW/cm2 (@1064 nm, 18 ns).15 Ag3SbS3 has a relatively wider bandgap of 2.2 eV than that of Ag3AsS3. The experimental measurement demonstrated that effective nonlinear coefficient deff of Ag3SbS3 is equal to be 7.8 pm/V under 10.6 µm.1 Unluckily, its LDT value is only 9 MW/cm2 (@1064 nm, 17ns),88 which is too small to bear high power laser.

Figure 5. Crystal structure of Ag3SbS3 viewed along (a) the [110] direction and (b) the [001] direction. Ba2SbInSe5 Ba2SbInSe5 crystallizes in the NCS space group Cmc21.89 For a single [InSbSe5]4- anionic chain, the 5s2 lone pair electrons in the heavily distorted [SbSe6]9octahedron, which are essential for the strong SHG response, are approximately pointing to the same direction roughly along the b axis (Figure 6). However, every two adjacent chains can be grouped into a pair within which the polarization of 5s2 lone pair electrons is almost canceled with each other. Such arrangement is destructive for the generation of large overall NLO response. Indeed, Ba2InSbSe5 displays the SHG signal intensity of only 1/10 of AGSe with similar particle size.89 In addition, Ba2SbInSe5 has a small bandgap equal to 1.92 eV.89



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Figure 6. Structure of the [InSbSe5]4- chain in compound Ba2InSbSe5, Ba2+ is omitted for clarity. Reprinted with permission from ref [89], Copyright 2013 Elsevier. Ba2BiInS5 Ba2BiInS5 adopts the Ba2SbInS5 structure type and crystallizes in the NCS orthorhombic Cmc21 space group.59 The crystal structure consists of 1D [BiInS5]4anionic polymeric chains with charge-compensating Ba2+ ions. An edge-sharing [BiS5]7- tetragonal-pyramid chain and a corner-sharing [InS4]5tetrahedra chain are interconnected with each other via corner-sharing S atoms to form the cis [BiInS5]4- anionic chain (Figure 7a). This arrangement leads to the Bi3+ lone-pair electrons in the parallel alignment fashion. In addition, partial electron density (PED) calculations showed that Bi3+ lone pair electrons are stereo-chemically active (Figure 7b).59 As a result, Ba2BiInS5 exhibits a comparable type-I phasematchable SHG response with that of KTP.59 It is reasonable that pseudo six-coordination environment of Bi3+ may decrease the stereo-chemically activity of 6s2 electrons. Accordingly, the SHG response of Ba2BiInS5 is much weaker than that of LiAsS2. Meanwhile, this compound has a moderate bandgap of 2.38 eV.59

Figure 7. (a) Crystal structure of Ba2BiInS5 (b) PED maps for compound Ba2BiInS5 from 2.5 eV to the Fermi level, and the electron density is represented from blue (0.0 e/Å3) to red (0.11 e/Å3). Adapted and reprinted with permission from ref [59], Copyright 2011 American Chemical Society. Ba23Ga8Sb2S38 Ba23Ga8Sb2S38 crystallizes in the NCS polar space group Cmc21 and exhibits an unusual zero-dimensional structure.51 The chemical formula can be rewritten to [(Ba2+)23(GaS45−)8(SbS33−)2], which contains totally isolated [GaS4]5- tetrahedra and discrete [SbS3]3pyramids with SALP electrons on Sb atoms (Figure 8). Structural analyses revealed that the second building unit, [SbS3]3- contributes negligibly to the SHG intensity because of overall centrosymmetric packing. Nevertheless, it helps to realize the disconnection of the asymmetric [GaS4]5building units, which remarkably leads to a strong powder SHG intensity. Ba23Ga8Sb2S38 exhibits the strongest SHG response in the IR region reported for sulfides to date (∼22 times that of AGS) though it is type-I non-phasematchable.51 It is clear that the constructive

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alignment of the dipole moments of the isolated [GaS4]5distorted tetrahedra gives rise to such a strong SHG response. Moreover, the isolated [GaS4]5- units have four dangling terminal S atoms, and thus, Ba23Ga8Sb2S38 has a higher sulfur ionic bonding component than any known 1D/2D/3D Ga/S species that contains bridging S. These features make Ba23Ga8Sb2S38 easily polarizable and a very strong SHG intensity can be realized. In addition, the bandgap of Ba23Ga8Sb2S38 is comparable with AGS (2.84 eV vs. 2.70 eV).51

Figure 8. Crystal structure of Ba23Ga8Sb2S38. Only half of the Sb atoms are shown because of the 50% occupancy. Adapted and reprinted with permission from ref [51], Copyright 2012 American Chemical Society. Cs5BiP4Se12 Cs5BiP4Se12 compound grows naturally as nanowires that crystallize in the polar Pmc21 space group.90 It features discrete molecular [Bi(P2Se6)2]5- anions, which are isolated by Cs+ cations (Figure 9a). There are two crystallographically unique Bi atoms, and each octahedrally coordinated Bi3+ center is capped by two chelating tridentate [P2Se6]4- units from opposite directions (Figure 9b). So there should be SALP 6s2 electrons on Bi(1) and Bi(2), as like in Ba2BiInS5. Cs5BiP4Se12 has a small bandgap 1.85 eV and is optically transparent from the visible to the mid-IR region (0.67 −18.7 µm). The SHG intensity of Cs5BiP4Se12 is two times larger than that of AGSe under 2.0 µm.90

Figure 9. (a) Crystal structure of Cs5BiP4Se12 viewed down the a-axis and (b) Coordination environments of Bi and P atoms in Cs5BiP4Se12. Adapted and reprinted with permission from ref [90], Copyright 2009 American Chemical Society.


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SnGa4Q7 (Q=S, Se) SnGa4Q7 (Q=S, Se) compounds crystallize in same monoclinic Pc space group,91 so we take SnGa4S7 as an example to describe crystal structure. The remarkable structures of the 3D frameworks were formed by the tetra-nuclear secondary basic structure unit [Ga4S11]10-, which was constructed with four [GaS4]5tetrahedra, and [SnS4]6- tetragonal pyramids locate in the cavities (Figure 10a). The Sn2+ atom is bonded to four S atoms at two short and two long distances, forming the [SnS4]6- tetragonal pyramid, which are antiparallel in interlayer and parallel in intra-layer along the b axis, respectively. The electron localization function (ELF) calculations display a non-spherical symmetric density distribution around each Sn atom, indicating the presence of 5s2 SALP electrons (Figure 10b).91 SnGa4S7 and SnGa4Se7 show strong phase-matching SHG response, which is 1.3 and 3.8 times that of AGS, respectively.91 The SHG responses of these two compounds are evidently boosted by the [SnQ4]6- unit with quadrangular pyramid structure. In addition, the bandgaps of them are large up to 3.10 and 2.55 eV,91 respectively, which can effectively attenuate the TPA effect pumped by 1064 nm laser. They are both promising IR NLO materials if the large size crystals could be grown.

eV,92 which is consistent with the dark red color of the crystal.

Figure 11. (a) Crystal packing structure of SnGa2GeS6 viewed down the b-axis with the unit cell marked (b) Macroscopic packing of [SnS5]8- square-pyramid in the structure. Reprinted with permission from ref [92], Copyright 2015 Royal Society of Chemistry. PbGa4S7 PbGa4S7 crystallizes in space group Pc of the monoclinic system (Figure 12a).93 The Ga atoms are coordinated by four S atoms in the distorted [GaS4]5tetrahedra while Pb atoms are bonded to five S atoms, forming [PbS5]8- distorted quadrangular pyramids with one S atom at the apex, proving the existence of the SALP 6s2 electrons on Pb cations (Figure 12b). PbGa4S7 exhibits relatively large bandgap of 3.08 eV and pretty strong SHG response larger than AGS.93 It is noted that there are two kinds of microscopic NLO active building blocks, namely the [PbS5]8- and [GaS4]5- units, which contributes to the SHG response of PbGa4S7. The overall polar arrangement of the [GaS4]5- units is beneficial for generating large NLO responses. But the spatial arrangement of the [PbS5]8quadrangular pyramid is a bit complicated. Figure 12c illustrates that the [PbS5]8- units have the same orientation in the layers parallel to the ac plane, which would be conducive for enhancing the NLO response. However, these [PbS5]8- quadrangular pyramids are almost antiparallel in adjacent layers along the b axis, which is unfavorable for generating large NLO response. That is, the SALP 6s2 electrons on Pb2+ do not contribute significantly to the overall NLO response.

Figure 10. (a) Crystal structure of SnGa4S7 viewed along the a axis and c axis (b) The ELF map of SnGa4Se7 at (001) plane cutting through the Sn and Ga atoms and the ELF value ranging from 0 (blue) to 1 (red). Adapted and reprinted with permission from ref [91], Copyright 2014 American Chemical Society. SnGa2GeS6 SnGa2GeS6 compound crystallizes in the NCS space group Fdd2.92 Ga and Ge atoms are randomly occupied in the ratio of Ga:Ge (2:1). In the structure, Sn2+ is coordinated to a distorted square-pyramid of five S atoms, demonstrating the stereochemical activity of the lone pair electrons, while the Ga and Ge atom are both tetrahedrally coordinated to four S atoms (Figure 11a). This compound exhibits a weak powder SHG signal only about 1/4 that of AGS.92 Figure 11b shows the overall arrangement of the [SnS5]8- square pyramids: although they are almost aligned in parallel in a pseudo chain along the c direction, the orientation of such adjacent pseudo chains is tilted to each other at a large degree, which is unfavorable for generating a large NLO response. The UV-vis-NIR diffuse reflectance spectrum shows that the bandgap of SnGa2GeS6 is 2.04



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Adapted and reprinted with permission from ref [94], Copyright 2015 American Chemical Society. Pb4Ga4GeQ12 (Q=S, Se) Pb4Ga4GeQ12 (Q=S, Se) compounds crystallize in same monoclinic P-421c space group.95 Pb4Ga4GeS12 and Pb4Ga4GeSe12 are semiconductors with optical bandgaps of 2.35 eV and 1.91 eV, respectively. Figure 14a shows the structure of Pb4Ga4GeSe12, in which the major structural motif is three-dimensional (3D) network constructed by chains of [GaSe4]5- tetrahedra that are interconnected by separated [GeSe4]4- tetrahedra at regular intervals. Pb2+ cations locate between the chains. The measurement of particle size versus SHG intensity indicates a non-phasematchable behavior in Pb4Ga4GeSe12. Pb4Ga4GeSe12 is only 2 times larger than AGS at a particle size of 30−46 µm,95 which is lower than PbGa2GeSe6 discussed in the last subsection. The ELF map indicates a spherelike isosurface at the Pb2+ site (Figure 14b), which means the 6s2 electrons on Pb2+ are stereochemically inert. Consequently, the polarization associated with the Pb2+ cation should be negligible in the Pb4Ga4GeSe12 compounds. As a result, the SHG effect of Pb4Ga4GeSe12 is weaker than PbGa2GeSe6, since the Pb2+ 6s2 lone pair electrons are active in the latter compound.

Figure 12. (a) Crystal packing structure of PbGa4S7 viewed down the b-axis with the unit cell marked (b) Macroscopic packing of [PbS5]8- quadrangular pyramid in the structure. Reprinted with permission from ref [93], Copyright 2015 Royal Society of Chemistry. PbGa2MSe6 (M=Si,Ge) Owing to the slightly different radii of Si and Ge, PbGa2SiSe6 and PbGa2GeSe6 belong to different space groups, Cc and Fdd2, respectively.94 Due to poor quality of PbGa2SiSe6 samples, no SHG signal was measured, so we focus on PbGa2GeSe6. In this structure, all of the Ga atoms and mixed (Ga/Ge) positions are bonded to four Se atoms forming the [GaSe4]5- and [(Ga/Ge)Se4] tetrahedra. And the [PbSe4]6- tetra-pyramids are located in the cavities (Figure 13a).94 The partial electron density (PED) contour demonstrates the lone pair 6s2 electrons of stereochemical activity in the [PbSe4]6- unit clearly (Figure 13b). PbGa2GeSe6 exhibits a strong SHG response of 5 times that of AGS, and the largest calculated SHG tensor component d33 is 224.7 pm/V at 2.0 µm.94

Figure 13. (a) Crystal packing structure of PbGa2GeSe6 viewed along the a-axis (b) PED maps for PbGa2GeSe6 from −5 eV to the Fermi level, and the electron density is represented from blue (0.0 e/Å3) to red (0.138 e/Å3).

Figure 14. (a) Crystal packing structure of Pb4Ga4GeSe12 (b) The Electron localization function (ELF) isofurfaces for the (020) plane of Pb4Ga4GeSe12, Contours are from 0 to 0.7. Adapted and reprinted with permission from ref [95], Copyright 2015 American Chemical Society. AAg2TeS6 (A=Rb, Cs) The layered compounds RbAg2TeS6 and CsAg2TeS6 crystallize in the NCS space group P63cm,96 in which Te is in a formal oxidation state of +4, making trigonal pyramidal [TeS3]2- isoelectronic to [AsS3]3-. As a result, there exist strongly SALP 5s2 electrons on Te atoms. Both compounds are composed of intercalated layers of neutral [Ag2TeS3] and [(A+)2(S6)2-] salt (A=Rb, Cs), which are flat and lie perpendicular to the c axis (Figure 15a). In [Ag2TeS3] layer, the [AgS4]7- polyhedra themselves are combined via common S atom corners to a network and [TeS3]2- trigonal pyramid locate in the channels (Figure 15b). UV-vis absorption spectroscopy reveals a band gap of 2.04 eV for RbAg2TeS6 and CsAg2TeS6.96 CsAg2TeS6 exhibits relatively weaker SHG response compared with AGSe. Phase-matching experiments using different sized particles of CsAg2TeS6 indicate that the material is phase-matchable under 1800 nm.96


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Figure 15. Crystal structure of CsAg2TeS6 viewed down the c-axis (a) and b-axis (b). Adapted and reprinted with permission from ref [96], Copyright 2010 American Chemical Society. Cs2TeS2 In addition to [TeS3]2- units, [TeS2]2- units can also be a NLO active group, as like in Cs2TeS2.97 It crystallizes in the NCS space group Cmc21 with four formula units per unit cell. Te2+ cation is surrounded by two sulfide anions in a V-shape, forming a boomerang-like complex [TeS2]2– anion (Figure 16a). This ligand carries two lone-pair electrons at the central Te2+ cation, which are stereochemically active (Figure 16b). All NLO-active units are stacked parallel to the (010) plane, forming a large dipole moment in crystal. Accordingly, we predict that Cs2TeS2 will exhibit a strong SHG response. Our calculations demonstrate that Cs2TeS2 has a very large SHG coefficient d33 (-128.07 pm/V), which is comparable with γ-NaAsSe2 (d33=162.3 pm/V).85 This result further confirms that SALP electrons can effectively enhance the SHG effect. To date, there are no measurements about SHG effect of Cs2TeS2. The DFT calculated bandgap is 2.04 eV, which is consistent with its dark-red color in experiments.97 Our predictions are waiting for experimental verifications.

Figure 16. (a) Crystal structure of Cs2TeS2 (b) electron localization function (ELF) map of Te atom (Cs+ is omitted for clarity), the rainbow hemispheres are SALP electrons.

Table 2. Experimental and calculated Eg, dij, and ∆n in the metal chalcogenides compounds containing SALP cations compounds Space group Eg(eV) SHG efficiency Calculated dij (pm/V) ∆n (cal) As3+ LiAsS254 Cc 1.60 d11=-45.9;d13=-53.8; 10×AGSe d33=98.2(static) (@1580nm,45-63µm) Ag3AsS315, 87 R3c 2.01 0.24 (@2090 nm)b 1.1×AGS (@2050nm) d22=16.6;d31=10.4 (@10.6µm) Tl3AsSe315 R3m 0.96 deff=20~30 (@10.6µm) 0.19 (@2056 nm)b β-LiAsSe252, 98 Cc 1.11 d11=28.4;d13=60.9; 1.08 (static) d33=836.5(static) γ-NaAsSe252, 85, Pc 1.75 d11=1.6;d13=15.8; 75×AGSe 99 d33=162.3(static)85 (@1580nm,45-63µm) d11=268.6(static) 99 3+ Sb Ag3SbS31 R3c 2.2 d22=8.2;d31=7.8 (@10.6µm) Ba2SbInSe589 Cmc21 1.92 0.1×AGSe (@2090nm,105-150µm) Ba23Ga8Sb2S3851 Cmc21 2.84 22×AGS (@2050nm,46-74µm) Bi3+ Ba2BiInS559, 100 Cmc21 1.55 d31=13.7;d32=13.7; 0.12 (@2050 nm) 0.8×KTP d33=16.6 (@2050nm) (@2050nm,150-200µm) Ba2BiInSe5100 Cmc21 1.40 d31=24;d32=23.5; 0.13 (@2050 nm) 230×SiO2 d33=28.1 (@2050nm) (@2050nm,150-200µm) Ba2BiInTe5100 Cmc21 1.28a d31=74.9;d32=74.2; 0.21 (@2050 nm) d33=98.6 (@2050nm) Cs5BiP4Se1290 Pmc21 1.85 2×AGSe (@2000nm,45-63µm) Sn2+ SnGa4S791 Pc 3.10 d11=-6.82;d12=-2.39; 1.3×AGS d13=-3.54;d15=9.12; (@2050nm,150-210µm) d24=-10.09;d33=15.7 (@2050nm) SnGa4Se791 Pc 2.55 d11=-4.82;d12=-1.77; 3.8×AGS


Crystal Growth & Design (@2050nm,150-210µm)

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SnGa2GeS692

Fdd2

2.04

0.25×AGS (@2090nm,105-150µm)

Pb2+ PbGa4S793

Pc

3.08

1.2×AGS (@2090nm,105-150µm)

PbGa2GeSe694

Fdd2

1.96

Pb4Ga4GeSe1295

P-421c

1.91

Pb5Ga6ZnS15101

Ama2

2.32

5.0×AGS (@2050nm,150-210µm) 2.0×AGS (@2050nm,30-46µm) weak signal

Te4+/Te2+ CsAg2TeS696

P63cm

2.04

Cs2TeS297

Cmc21

2.04a

a

>W6+ ≈ Ti4+ ≈ Nb5+>Ta5+>>Zr4+ ≈ Hf4+.102-103 This tendency should be the same in the chalcogenides, but the detailed regulation is still unclear since only very limited number of metal chalcogenides with d0 transition metal cations centered units have been found till now. CsTaS3 CsTaS3 crystal crystallizes in P63mmc space group,104 just similar to BaVS3 structure type. Ta5+ centers are slightly displaced along the [111] direction in the [TaS6] octahedra, creating two discrete sets of Ta-S bond distances as a result of C3 SOJT effect (Figure 17). So [TaS6] group is the most typical SOJT octahedron in metal chalcogenides.

Unfortunately, there is no any SHG response in CsTaS3 because of its inversion center.

Figure 17. Crystal packing structure of CsTaS3. AZrPSe6 (A=K, Rb, Cs) The compounds AZrPSe6 (A=K, Rb, Cs) crystallize in the same polar space group Pmc21,105 so we take KZrPSe6 as an example. It features parallel chains of the infinite 1D [ZrPSe6]- anion separated by the alkali metal K+ ions (Figure 18a). Zr4+ ions are coordinated to seven Se atoms in a distorted SOJT [ZrSe7] bicapped trigonal prismatic geometry (Figure 18b). All Zr4+ ions are connected to the [PSe3]- polymeric backbone formed by the condensation of corner-sharing tetrahedral [PSe4]3- units (Figure 18c). Each P atom has a terminal P-Se bond projecting out from the one dimensional [PSe3]- chain structure. The Zr atoms are also bridged with Se22- groups. So, the chemical formula could be rewritten as [K+Zr4+ P5+(Se2-)4 (Se2)2-]. All three compounds show very strong and sharp absorption edges at ∼2 eV.105 In general, changes of the alkali metal do not show a major effect on the band gap of the covalent network. Under similar experimental conditions, the SHG response of crystalline RbZrPSe6 and CsZrPSe6 are ∼15 and 10 times stronger than that of AGSe.105 The K analogue shows a weaker SHG signal intensity than AGSe. Phase matching experiments of CsZrPSe6 indicate that this material is type-I phase matchable.105


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Figure 18. (a) Crystal packing structure of KZrPSe6 (b) coordination environment of Zr and P cations and (c) 1D [ZrPSe6]- anion chain. Adapted and reprinted with permission from ref [105], Copyright 2008 American Chemical Society. TiP2S6 TiP2S6 belongs to Fdd2 space group and contains [TiS6]8- distorted SOJT octahedra.106 In the structure, each P atom is surrounded by three S atoms and every two P atoms are interconnected, forming a [P2S6]4- group. The P-P atom pairs are located within the planes perpendicular to the c-axis and have parallel orientation with each other (Figure 19). The further interconnections between [P2S6]4and [TiS6]8- groups construct a three-dimensional network. In this way the Ti atoms attain the distorted octahedral coordination with distances Ti-S ranging from 2.453Å to 3.451Å in the SOJT [TiS6]8- octahedra. The calculated SHG tensor d15 is 15.45 pm/V,17 which is slightly larger than d36 of AGS. In addition, the optical anisotropy (i.e., birefringence) can be significantly enhanced by introducing the SOJT Ti4+ cations, which is large up to 0.33 at 2090 nm. However, the bandgap of TiP2S6 is relatively small (2.56 eV).

Figure 19. Crystal packing structure of TiP2S6 2.3.2 Metal chalcogenides containing d10 transition metal cations centered units Similar to the situation in the last subsection, the number of metal chalcogenides with d10 transition metal cations centered units is very scarce. The only known case is Cd2P2S6. Cd2P2S6 Cd2P2S6 crystallizes in the trigonal symmetry with R3 space group.107 Each ethane-like [P2S6]4− group is linked by six edge-sharing [CdS6]10− octahedral groups with the Cd−S lengths ranging from 2.70 to 2.75 Å (Figure 20). Because of the approximately centro-symmetric arrangement of the basic building units, the NLO response of Cd2P2S6 is rather small (only 2×KDP).17 Similar to TiP2S6, the birefringence value of Cd2P2S6 is enlarged to 0.27 owing to the introduction of distorted [CdS6]10- units.

Figure 20. Crystal packing structure of Cd2P2S6 In addition, one may expect that the cooperation of SOJT and SALP cations in structure can further enhance the NLO effect. Keeping this in mind, Bera et al successfully synthesized a series of compounds A3Ta2AsS11 (A = K, Rb, Cs) in which the two types of NLO active units are simultaneously existed.55 A3Ta2AsS11 (A = K, Rb, Cs) These compounds feature parallel [Ta2AsS11]3− chains that consist of bimetallic SOJT [Ta2S11]6− units linking with SALP [AsS3]3- pyramid.55 The sizes of the alkali metal atoms have profound influence on the packing of the chains. The K+ and Rb+ cations favor the NCS packing of [Ta2AsS11]3− chains with the polar space group Cc (Figure 21a), whereas the larger Cs+ cations favor the CS packing of [Ta2AsS11]3− chains with the P21/n space group (Figure 21b). The NCS packing of [Ta2AsS11]3− chains results in the in-phase alignment of the [AsS3]3pyramids. The common dimeric core [Ta2S11]6- in all three compounds is derived from the trigonal face sharing connection of two distorted [TaS7]9- pentagonal bipyramids (Figure 21c). The large nonlinear optical SHG response is the most significant property of the polar K3Ta2AsS11 compounds. In the range 700-900 nm, the SHG efficiency of K3Ta2AsS11 is ∼15 times stronger than that of AgGSe.55 However, particle size dependent SHG measurements indicates that both A3Ta2AsS11 (A = K, Rb) are type-I non-phasematchable at 770 nm. In addition, K3Ta2AsS11 has a slightly more narrowed bandgap than that of AGS (2.21 eV vs. 2.7 eV). In order to separate the contribution of the pyramidal [AsS3]3and [Ta2S11]6- units to SHG coefficient, a NCS compound Rb4Ta2S11 was also reported,108 which has the similar polysulfide [Ta2S11]4- units but no [AsS3]3- units. Powder SHG response of Rb4Ta2S11 is only 4 times that of AGSe, suggesting that the pyramidal [AsS3]3- unit may play a predominant role on the SHG response in K3Ta2AsS11.



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Figure 21. Crystal packing structure of (a) Rb3Ta2AsS11 and (b) Cs3Ta2AsS11. (c) A single 1D [Ta2AsS11]3- chain, showing the connectivity between [AsS3]3- trigonal pyramids and asymmetric [Ta2S11]6- units. Adapted and reprinted with permission from ref [55], Copyright 2009 American Chemical Society. In summary, the experimental and calculated key NLO parameters for the metal chacogenides containing SOJT effect cations are listed in Table 3. Clearly, the birefringence and SHG effect of these metal chalcogenides can be significantly improved. Nevertheless, the relatively small Eg (10×LiNbO3 (@1064nm) SHG active (@1064nm) 12.2×AGS (@2050nm,46-74µm) 11.1×AGS (@2050nm,46-74µm) 9.8×AGS (@2050nm,46-74µm)

KCd4Ga5Se12150 RbCd4Ga5Se1215

R3 R3

2.16 2.19

26.8×AGS (@2050nm,46-74µm) 19.3×AGS (@2050nm,46-74µm)

CsCd4Ga5Se12150

R3

2.21

16.6×AGS (@2050nm,46-74µm)

RbCd4In5Se12150 CsCd4In5Se12150

R3 R3

1.57 1.62

39.2×AGS (@2050nm,46-74µm) 35.1×AGS (@2050nm,46-74µm)

RbMn4In5Se1215

R3

1.76

CsMn4In5Se12150 RbZn4In5Se12175 CsZn4In5Se12175

R3 R3 R3

1.79 2.06 2.11

172

147

0

0

d36=15.4(static) d36=29.2(static) d36=33.2(static) deff=20 d11=14.6;d15=13.9; d22=12.2;d33=26.4 (@2050nm) -

0.27(@static)174 0.003 (static)

0.010 (static)

28.3×AGS (@2050nm,46-74µm)

d11=48.6;d15=45.7; d22=43;d33=81.6 (@2050nm) d11=26.8;d15=23.7; d22=22;d33=42.1 (@2050nm) -

24.9×AGS (@2050nm,46-74µm) 26.7×AGS (@2050nm,46-74µm) 25.0×AGS (@2050nm,46-74µm)

d33=49.7 (@2050nm) -


-

0.014 (static) -


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CsMn4In5Te12151 CsZn4In5Te12151

R3 R3

1.48 1.61

1.7×AGS (@2050nm,46-74µm) 4.3×AGS (@2050nm,46-74µm)

CsCd4In5Te12151

R3

1.42

9.2×AGS (@2050nm,46-74µm)

CsGaSn2Se6163 CsInSn2Se6163 KAg2PS4 153 KAg2SbS4153 RbAg2SbS4153

R3 R3 I-42m I-42m P3221

1.78 1.87 3.02 2.20 2.30

3.5×AGS (@2050nm,150-210µm) 4.0×AGS (@2050nm,150-210µm) No data No data No data

K4GeP4Se12 56 Rb4GeP4Se1256 Cs4GeP4Se1256 KPSe6 46-47

Pca21 Pca21 Pca21 Pca21

2.00 2.00 2.00 2.16

RbPSe646-47

Pca21

2.18

K0.9Cs0.1PSe648

Pca21

2.10

K0.8Cs0.2PSe648

Pca21

2.10

K0.7Cs0.3PSe648

Pca21

2.10

K0.6Cs0.4PSe648

Pca21

2.10

β-CsPSe648

P-421c

1.9

P3121 P-4 Pna21 Pna21

2.08 2.17 2.38 -

30×AGSe (@1460nm,45-63µm) 9×AGSe (@1460nm,45-63µm) 5×AGSe (@1460nm,45-63µm) dij=78.8±3.5 (@1610nm,125-150µm) dij =73.2±2.6 (@1610nm,125-150µm) dij =83.1 ± 5.1 (@1550nm,32-45µm) dij =68.5 ± 4.3 (@1550nm,32-45µm) dij =78.2 ± 4.8 (@1550nm,32-45µm) dij =81.7 ± 5.0 (@1550nm,32-45µm) dij =14.8±2.8 (@1550nm,32-45µm) 50×AGSe (@1580nm,45-63µm) 0.25×AGSe (@2000nm,45-63µm) 65×AGSe (@2000nm,125-150µm) dij =59 (@2000nm,125-150µm)

Pna21

-

dij =27 (@2000nm,125-150µm)

K2P2Se650 Cs2P5Se12161 Na2Ge2Se553 Na2Ge2Se4.55Te0.45

Page 22 of 38 d11=95.1;d15=86.2; d22=72.7;d33=149.8 (@2050nm) d11=101.8;d15=106.7; d22=89.1;d33=184.3 (@2050nm) d15=53.3 (@2050nm) d15=63.9 (@2050nm) d14=8.74 (static) d14=11.56(static) d12=d16=d22=8.43 (static) d15=-19.5;d24=-17.9; d33=75.6 (static)85 d15=-19.5;d24=-11.4; d33=74.7 (static)85 -

0.022 (static) 0.013 (static) 0.05 (@2050nm) 0.07 (@2050nm) 0.071 (@1064 nm) 0.053 (@1064 nm) 0.008 (@1064 nm) -

-

-

-

-

-

-

-

-

d12=26.8 (static)85 -

0.145 (static)176 -

53

Na2Ge1.64Sn0.36Se5

-

-

53

2.6.2 Metal chalcogenides containing main group centered tetrahedra and alkaline-earth metal cations BaM4S7 (M=Al, Ga) These two compounds are isostructural to Pmn21 space group and were firstly reported in 1983.177 In BaGa4S7 structure, tetrahedral [GaS4]5- groups are aligned parallel along the c axis and connected to each other by sharing their vertexes (Figure 42a). In 2009, a large size up to Φ10 × 100 mm3 BaGa4S7 crystal has been grown by Ye’ group.37 The crystal exhibits high transparency in a broad spectral range from 0.35 to 13.7 µm, covering two important atmospheric windows 3-5 and 8-12 µm (Figure 42b). Its bandgap is large up to 3.54 eV, implying that it would have high LDT value. Moreover, Markers fringe measurements show that it has a large SHG coefficient (d33=12.6 pm/V), which is comparable with benchmark material AGS. The SHG coefficients of BaAl4S7 is smaller, only half of that of BaGa4S7.178 In 2011, the refractive indices and birefringence of BaGa4S7 were measured, which showed a moderate birefringence value of ∆n=0.04 at 1064 nm.179 In 2012, the idler laser output within wavelength ranged from 5.5 to 7.3 µm was achieved by BaGa4S7 crystal through optical parametric oscillator (OPO) technique.180 In 2013, 90° phase-matched fourth-harmonic generation of the CO2 laser wavelength at 10.6 µm was obtained in high-quality BaGa4S7 crystal.181 This further proved that BaGa4S7 is a very

promising material for practical applications to high power frequency conversion in the mid-IR region.

Figure 42. (a) Crystal packing structure of BaGa4S7 (b) Transmittance curves of the BaGa4S7 crystal in the UV and IR, inert graph: polished piece of BaGa4S7 crystal. Adapted and reprinted with permission from ref [37], Copyright 2009 American Chemical Society.


Page 23 of 38

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BaM4Se7 (M=Al, Ga) These two compounds are isostructural and we take BaGa4Se7 as an example.38, 182 The structure of BaGa4Se7 is illustrated in Figure 43a. The [GaSe4]5- tetrahedra are connected to each other by corner-sharing to form a 3D framework with Ba2+ cation in the cavities. Each Ba atom is coordinated to a bicapped trigonal prism of eight Se atoms. Single crystals of BaGa4Se7 were grown using Bridgman–Stockbarger method.183 It is highly transparent ranged from 0.47 to 18 µm with a strong absorption peak around 15 µm, which is sufficient to cover 3–5 µm and 8–12 µm of atmospheric transparent windows (Figure 43b). Markers fringe measurements determined the two independent SHG tensors of d11=24.3 and d13=-20.4 pm/V,184 which agree well with calculated results (d11=18.2 and d13=-20.6 pm/V). In addition, its birefringence value is 0.07 at 1064 nm, which is also consistent with calculated value 0.08.179 In comparison, BaAl4Se7 have a wider bandgap (3.40 eV) and a weaker SHG effect (only 0.5×AGS). 182

Recently, 3–5 µm and 6–11.4 µm idler tuning range outputs have been realized in the BaGa4Se7 crystal by optical parametric amplifier (OPA).185-186 In 2016, 4.34–5.19 µm and 2.7–17 µm idler outputs were further achieved in this crystal pumped by a Ho:YAG laser at 2090.6 nm and Nd:YAG laser at 1064 nm by OPO, respectively.187-188 In addition, the Terahertz (THz) difference frequency generation using BaGa4Se7 was analyzed theoretically and the phase-matching conditions were calculated.189 It demonstrates the promising prospect of THz generation by using BaGa4Se7 as the NLO crystal. So, BaGa4Se7 crystal will be a very good mid-IR or even far-IR NLO material in future applications.

Figure 43. (a) Crystal packing structure of BaGa4Se7 (b) Transmittance curves of the BaGa4Se7 crystal in the UV and IR, inert graph: polished piece of BaGa4Se7 crystal. Adapted and reprinted with permission from ref [38, 183], Copyright 2010 American Chemical Society and 2012 Elsevier. BaGa2MQ6 (M=Si, Ge, Sn; Q=S, Se) This series of compounds include five members and they are isostructural. We select BaGa2GeS6 as an example to describe their structure. BaGa2GeS6 crystallizes in the NCS polar space

group R3.43-44 The metal positions are randomly occupied by both Ga and Ge in the molar ratio of 2:1.It features a 3D framework constructed by [(Ga/Ge)S4] tetrahedra and Ba2+ cations are filled in the space of 3D framework. There is one (Ga/Ge)–S bond aligned roughly along the c-direction for each [(Ga/Ge)S4] tetrahedron (Figure 44a). Such polar arrangements can result in strong SHG response. The bandgaps are 3.75 eV, 3.23 eV, 2.88 eV, 2.22 eV and 1.95 eV (corresponding to the short absorption edges of 330 nm, 380 nm, 430 nm, 560 nm and 635 nm) for BaGa2SiS6,43 BaGa2GeS6,43 BaGa2SiSe6,43 BaGa2GeSe643 and 190 BaGa2SnSe6, respectively. Moreover, all these compounds exhibit high SHG efficiency. In particular, BaGa2SnSe6 show the strongest SHG response about 5.2 times that of AGS.190 Very recently, large sized BaGa2GeS6 and BaGa2GeSe6 crystals have been grown by Russian researchers.191 These two crystals have wide transparent region ranged from 0.41-11.8 µm and from 0.58-18 µm, respectively (Figure 44b and 44c). The birefringence and effective SHG coefficients were also measured, which agree well with our previous calculated results.43 In comparison with BaGa4S7 and BaGa4Se7 crystals, BaGa2GeS6 and BaGa2GeSe6 possess higher symmetry and are optically uniaxial, which might be more favourable to practical applications.

Figure 44. (a) Crystal packing structure of BaGa2GeS6. Transmission of (b) a 9.4 mm thick sample of BaGa2GeS6 and (c) a 4.84 mm thick sample of BaGa2GeSe6. Adapted and reprinted with permission from ref [44, 191], Copyright 2012 Elsevier and 2016 Optical Society of America. Ba2Ga8MS16 (M=Si/Ge) These two metal sulfides are isostructural and crystallize in the NCS space group P63mc. We select Ba2Ga8GeS16 as a representative.192 It adopts the 3D framework structure that consists of alternate stacking of two distinct tetrahedral layers 1 and 2 as shown in Figure 45a. The layer 1 is constructed by corner-sharing [GaS4]5- tetrahedra (Figure 45b) while layer 2 is built up from mixed [(Ga/Ge)S4] tetrahedral units with an occupancy ratio of Ga:Ge=5:1 (Figure 45c). The charge-balanced Ba2+ cations reside in the tunnels along the c direction and at one of the interfaces between the pure [GaS4]5- and mixed [(Ga/Ge)S4] layers. The UV−vis−NIR diffuse-reflectance spectra show strong absorption edges roughly at 3.4 and 3.0 eV respectively for Si- and Ge-analogues.192 The measured SHG intensities of Ba2Ga8GeS16 are 0.9 times that of AGS with phase-matching behavior. These results indicate that Ba2Ga8GeS16 can be a good candidate for high-power mid-IR NLO applications.



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 24 of 38

behavior at 2.09 µm at the 38−88 µm particle size.195 The calculated ∆n is ∼0.07 at the wavelength ∼1 µm. Moreover, the calculated SHG tensors of BaHgS2: d31=5.2, d32=−16.7 and d33=−59.7 pm/V, which is larger than AGS (d36=13 pm/V) and AGSe (d36=33 pm/V).195 However, narrow bandgap of BaHgS2 may cause strong TPA under 1064 nm and low LDT value.

Figure 45. (a) Crystal packing structure of Ba2Ga8GeS16. (b) Tetrahedral layer 1 constructed by the pure [GaS4]5tetrahedra. (c) Tetrahedral layer 2 made up of mixed [(Ga/Ge)S4] tetrahedral. Adapted and reprinted with permission from ref [192], Copyright 2015 American Chemical Society. Ba4CuGa5Q12 (Q=S, Se) This series of compounds are isostructural and belong to P-421c space group.193 Ba4CuGa5S12 adopts a 3D framework structure, assembled by [GaS4]5- and [CuS4]7- tetrahedra and Ba2+ cations distributed within the framework tunnels (Figure 46a). There are two fundamental building units in this structure. The first building unit consists of [CuS4]7- and [Ga(1)S4]5tetrahedra by sharing edges and corners, forming an infinite column of [CuGa4S10]7− along the c axis (Figure 46c). The second building unit is the [Ga(2)S4]5- tetrahedron, which is bonded to four infinite columns related to each other by 21 symmetry (Figure 46b). In this series compounds the bandgaps decreases from 2.82 eV to 1.45 eV as S atoms are replaced by Se.193 The SHG effect of Ba4CuGa5S12 and Ba4CuGa5Se12 is about 3.5 and 1.5 times larger than that of AGSe under 1536 nm irradiation.193

Figure 46. (a) Polyhedron scheme of the framework in Ba4CuGa5S12. (b) Structure of the asymmetric unit [CuGa5S17] in Ba4CuGa5S12. (c) Infinite column of [CuGa4S10]7− along the c axis. Color scheme: [CuS4]7- tetrahedra, cyan; [Ga(1)S4]5- tetrahedra, blue; [Ga(2)S4]5- tetrahedra, purple. Adapted and reprinted with permission from ref [193], Copyright 2013 American Chemical Society. BaHgS2 BaHgS2 was first synthesized in 1981,194 and its space group was reported as Pmc21. The crystal structure of BaHgS2 is composed of [HgS4]6- tetrahedral units (Figure 47b) and isolated dumbbell-shaped [HgS2]2- (Figure 47c), forming a 3D framework structure with charge balanced Ba2+ cations (Figure 47a). BaHgS2 has a bandgap of 1.93 eV,195 which is much smaller than that of AGS (2.70 eV). The SHG measurements exhibit 6.5 times that of AGS with a non phasematching

Figure 47. (a) Crystal packing structure of BaHgS2. (b) four-fold coordinated [Hg(2)S4]6- units. (c) linear coordinated [Hg(1)S2]2- units. Adapted and reprinted with permission from ref [195], Copyright 2015 American Chemical Society. NaBaMQ4 (M=Ge, Sn; Q=S, Se) This series of compounds contain alkali metal and alkali-earth metal cations simultaneously. They belong to different space group I-42d and R3c (Na2BaGeS4, Na2BaGeSe4, (Na2BaSnS4) Na2BaSnSe4).196 In the structure of Na2BaSnS4, the [BaS8]14polyhedra are first connected with each other by sharing edges to make up wavelike 1D [BaS6]10- chains, and those chains are linked together with isolated [SnS4]4- tetrahedra by sharing corners and edges to form layered structures (Figure 48b). These layers are further connected with the common S atoms to form a 3D tunnel structure with Na+ cations located inside the tunnels (Figure 48a). In the structure of Na2BaSnSe4 (similar to Na2BaGeSe4 and Na2BaSnSe4), the distorted [BaSe7]12- polyhedra are connected with the isolated [SnSe4]4- units by sharing corners or edges to make up the tunnel structure (Figure 48c). The [NaSe6]11- units link together to form a so-called 24-membered-ring (24-MR) motif by sharing edges, and other units ([BaSe7]12- and [SnSe4]4-) locate within the 24-MR (Figure 48d). The experimental bandgaps of Na2BaSnS4, Na2BaGeS4, Na2BaSnSe4, Na2BaGeSe4 are 3.27 eV, 3.70 eV, 2.25 eV and 2.46 eV, respectively.196 The NLO properties of the four compounds were recorded by using a 2.09 µm laser. Two Se-analogues are not phase matchable, while two S-analogues are phase matchable. The SHG effects of Na2BaSnS4 and Na2BaGeS4 are circa 0.5 and 0.3 times that of AGS, which is consistent with calculated dij=4.76 and 3.63 pm/V, respectively.196 These two compound satisfies the fundamental condition as a good mid-IR NLO material (Eg > 3.0 eV and dij>10×KDP), so they might be promising candidates for mid-IR NLO applications.


Page 25 of 38

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Crystal Growth & Design [SnS4]4- units. (c) View of the tunnel structure of Na2BaSnSe4 (d) [NaSe6]11- octahedra are connected together to form 24-MR. Adapted and reprinted with permission from ref [196], Copyright 2016 Wiley. The detailed linear and nonlinear optical properties of above compounds are listed in Table 7. In addition, there are quite a few other types of metal chalcogenides which contain alkaline-earth metal cations, such as Ba4CuGa5S12-xSex,193 Ba5In4Te4S7,197 BaCdSnS4,198 Ba3CdSn2S8,198 BaCdSnSe4,199 and Ba4Ga4GeSe12200. These compounds are SHG active, and the above discussions on structure-property relationship are also available. But they are not discussed here due to the length limit of this review.

Figure 48. (a) The 3D framework of Na2BaSnS4 with Na-S bonds omitted for clarity (b) a layered structure formed by infinite [BaS6]10- chains connected with isolated Table 7. Experimental and calculated Eg, dij, and ∆n in the metal chalcogenides containing main tetrahedra and alkaline-earth metal cations compounds Space Eg(exp) SHG efficiency calculated dij (pm/V) group BaAl4S7178 Pmn21 3.74a d31=3.15;d32=2.20; d33=-6.13(static) BaGa4S737, 179, 201 Pmn21 3.54 d31=-6.21;d32=4.86; 1.4×LiGaS2 (@2050nm,150-200µm) d33=16.6(static) d31=-5.1;d32=-5.7;d33=12.6 BaAl4Se7182

∆n (cal) 0.05(static) 0.063 (@1064nm) 0.11 (static)178 0.04 (@1064nm)b 0.052 (@1064nm)

Pc

3.40

0.5×AGS (@1064nm,80-100µm)

Pc

2.64

2-3×AGS (@1064nm,80-100µm) d11=24.3;d13=-20.4 (@1064nm)184

BaGa2SiS643

R3

3.75

1.0×AGS (@2090nm,80-100µm)

BaGa2SiSe643

R3

2.88

0.5×AGSe (@2090nm, 80-100µm)

BaGa2GeS643-44

R3

3.2343, 3.2644

1.0×AGS (@2090nm, 80-100µm),43 2.1×AGS (@2050nm, 150-212µm)44

BaGa2GeSe643-44

R3

2.2243, 2.8144

1.0×AGSe (@2090nm, 80-100µm)43, 3.5×AGS (@2050nm,150-212µm)44

BaGa2SnSe6190

R3

1.95

5.2×AGS (@2090nm, 105-150µm)

Ba2Ga8SiS16192 Ba2Ga8GeS16192 Ba6Ag4Sn4S16204 Ba6Ag2.7Sn4.3S16

P63mc P63mc I-43d I-43d

3.4 3.0 2.37 1.58

0.9×AGS (@1950nm,200-300µm) 8.2×AGSe (@1350nm,150-200µm) 1.0×AGSe (@2000nm,20-32µm)

I-43d

1.38

1.0×AGSe (@2000nm,20-32µm)

-

0

P-421c P-421c P-421c

2.82 1.45 2.05

1.3×AGSe (@1796nm,106-125µm) 0.6×AGS (@1796nm,106-125µm) 1.1×AGS (@1796nm,106-125µm)

-

-

P-421c P-421c

2.18 2.16

weak signal (@2090nm, 80-100µm) weak signal (@2090nm, 80-100µm)

-

-

BaGa4Se738, 183, 202-203

179,

205

Ba6Ag2.7Sn4.3S16 205

Ba4CuGa5S12193 Ba4CuGa5Se12193 Ba4CuGa5S9Se31 93

Ba4Ga4GeSe12200 Ba4Ga4SnSe12206

d11=-2.8;d15=5.2; d12=-0.68;d13=4.2; d24=-3.7;d33=0.28 (static) d11=18.2;d15=-15.2; d12=5.2;d13=-20.6; d24=14.3;d33=-2.2 (static) d11=-4.3;d15=-6.7; d22=-7.4;d33=8.4 (static) d11=-8.3;d15=-13.9; d22=-15.3;d33=12.3 (static) d11=5.6;d15=9.4; d22=10.5;d33=-12.0 (static) d11=13;d15=24.7; d22=-27.4;d33=-23 (static) d11=62.91;d15=11.6; d22=2.8;d33=50.62 (static) -

group cations centered


0.08 (@1064nm) 0.07 (@1064nm)b 0.05 (@1064nm) 0.07 (@1064nm) 0.068 (@1064nm) 0.05-0.07191 (@0.44-10 µm)b 0.15 (@1064nm) 0.08-0.11191 (@0.66-10 µm)b 0.165 (@1064nm) 0 0


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Ba5In4Te4S7197

Imm2

2.13

0.5×AGS (@2050nm,100µm)

BaCdSnS4198 BaCdSnSe4199

Fdd2 Fdd2

2.30 1.79

5×AGS (@2090nm,38-55 µm) 1.6×AGS (@2090nm,38-55 µm)

Ba5CdGa6Se15207 Ba3CdSn2S8198 BaHgS2195

Ama2 I-43d Pmc21

2.60 2.75 1.93

0.5×AGS (@2090nm, 150-210µm) 0.8×AGS (@2090nm,38-55 µm) 6.5×AGS (@2090nm,38-55 µm)

Na2BaGeS4196 R3c 3.70 0.3×AGS (@2090nm,200-250 µm) Na2BaGeSe4196 R3c 2.46 0.9×AGS (@2090nm, 55-88 µm) Na2BaSnS4196 I-42d 3.27 0.5×AGS (@2090nm,200-250 µm) Na2BaSnSe4196 R3c 2.25 1.3×AGS (@2090nm,55-88 µm) a calculated by DFT methods; b experimental results From the data in Table 7, one may conclude that the bandgap of metal chalcogenides can be enlarged by introducing the alkaline-earth metal cations with low electronegativity, similar to the cases in Section 2.6.1. BaGa4S7, BaGa2SiS6 and Na2BaGeS4 possess wide bandgap of 3.54 eV, 3.75 eV and 3.70 eV, respectively.37, 43, 148 This indicates that these compounds would have much higher LDT value than AGS. Indeed, the measurements on large single crystals revealed that the LDT value of BaGa4S7 is three times that of AGS.201 Up to now, the Ba-containing compounds are the most studied, but the researches on Caand Sr-containing compounds are relatively scarce, so the further studies are desirable. In addition, great efforts should be made to grow high quality single crystals for these materials. In summary, we believe that there must exist more promising materials with superior mid-IR NLO performance in the metal chalcogenides containing main group cations centered tetrahedra. The comprehensive investigations on this materials family combined experiments and analysis procedures should be focused on. 2.7. Diamond like (DL) structure metal chalcogenides In Section 2.6.1., we have discussed the metal chalcogenides that contains main group cations centered tetrahedra and alkali/coin metal cations, In fact, there exist another type of compounds with similar structure features called diamond like (DL) structures. Many of them exhibit superior mid-IR NLO properties,165 so we specially discuss them in this section. Diamond-like (DL) compounds, as like chalcopyrite (AGS and ZnGeP2), represent the structures that are derived from that of diamond, in either cubic or hexagonal closest packing forms.208 These compounds are built from tetrahedral building blocks that are oriented along one special crystallographic axis, rendering the structures inherently NCS, the first criterion for SHG. In addition, the aligned arrangement of tetrahedra would result in the additive superposition of the microscopic second-order susceptibility tensors of the units, and exhibit large SHG response. Furthermore, the very abundant stoichiometry and composition in the DL metal chalcogenides actually provides a large treasury for synthesis and design new materials with superior mid-IR NLO performances. This makes DL compounds attractive materials in NLO applications.

Page 26 of 38 d31=14.4;d32=18.8; d33=13.7(@2050nm) d31=14.3;d32=-19.8; d33=25.3 (static) d31=5.2;d32=-16.7; d33=-59.7 (static) dij=3.76 (static) dij=10.69 (static) dij =4.63 (static) dij =12.25 (static)

0.11 (@1064nm) 0 0.07 (@1000nm) 0.037 (@1000nm) 0.026 (@1000nm) 0.070 (@1000nm) 0.011 (@1000nm)

in the closest packing form. Indeed, all atoms are located in tetrahedral coordination environments. There are no defect cation sites in crystal structure.208 Binary normal DL chalcogenides The typical binary DL structures include sphalerite (α-ZnS) and wurtzite (β-ZnS) structure. α-ZnS belongs to cubic F-43m space group, while β-ZnS belong to hexagonal P63mc space group. Their crystal structures are displayed in Figure 49a and 49b. Clearly, all [ZnS4]6- tetrahedra in sphalerite and wurtzite structures are arranged aligned along [111] and [001] directions, respectively. This structure feature is very favorable for the superposition of microscopic second-order susceptibility of [ZnS4]6- anion units. Both experimental and calculated SHG coefficients reveal that the two crystals have large NLO effect (> 8 pm/V),165, 209 as listed in Table 8. Meanwhile, both of α-ZnS and β-ZnS possess the large bandgap (> 3.0 eV).210-211 Hence, one may conclude that the DL structure can reach the good balance between NLO effect and bandgap. Nevertheless, the optical refractive indices in α-ZnS are isotropy and the birefringence is zero owing to its cubic structure, while β-ZnS only have a very small birefringence 0.003 because the [ZnS4]6- tetrahedra are little distorted from the regular tetrahedral shape in the wurtzite structures. Therefore, binary normal DL metal sulfides are not suitable for mid-IR SHG application owing to its small birefringence. Ternary normal DL chalcogenides The commonly existed ternary normal DL metal chalcogenides can be catalogued into three types: I-III-VI2, I2-IV-VI3 and I3-V-VI4. The I-III-VI2 type (I=Li, Ag, Cu; IV=Al, Ga, In; VI=S, Se, Te) compounds usually have the chalcopyrite structure, while I3-V-VI4 type (I=Li, Ag, Cu; V=P, As, Sb; VI=S, Se, Te) compounds usually have the enargite or famatinite structure. The I2-IV-VI3 type (I=Ag, Cu; IV=Si, Ge, Sn; VI=S, Se, Te) compounds are usually featured with the renierite structure which is much less common than the former two structures. Up to now, only the NLO properties of I-III-VI2 types have been studied systematically. Many of them are also commercial IR NLO crystals, including AGS, AGS, LiGaS2, LiGaSe2, LiInS2, LiInSe2 etc.143

2.7.1 Normal diamond like (DL) structure metal chalcogenides Normal DL structures derive from the sphalerite or wurtzite structure. The cation and anion sublattices are both


Page 27 of 38

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Figure 49. Crystal structure of α-ZnS, (b) β-ZnS, (c) AGS, (d) LiGaS2 Quarternary normal DL chalcogenides The known quarternary normal DL metal sulfides have three formula, including I2−II−IV−VI4, I−II2−III–VI4, and I4−II−IV2−VI7. Till now, only I2−II−IV−VI4 type compounds have been studied owing to their good NLO properties, so we focus on this type here. In this type of quarternary normal DL materials six structures have been reported, three of which are derived from hexagonal lonsdaleite, wurtz-stannite (space group Pmn21), lithium cobalt (II) silicate Li2CoSiO4 (space group Pna21), and wurtz-kesterite (space group Pn), respectively, while the other three are derived from the cubic diamond structures for stannite (space group I4 2m), kesterite (space group I4 ) and disordered kesterite (space group I4 2m), respectively.212 To date, only the former three space group has been reported to be SHG active.61-62, 213-214 (i) Wurtz-stannite Li2CdGeS4 and Li2CdSnS4 are the first compounds to report the SHG effects in quarternary DL chalcogenides.62 Both materials crystallize in the orthorhombic space group Pmn21. All of the tetrahedral building blocks are oriented along c axis, resulting a polar structure (Figure 50). The [CdS4]6-, [(Ge/Sn)S4]4tetrahedra are fairly regular while the greatest distortion from ideal occurs in the [LiS4]7- tetrahedra.

Figure 50. Crystal structure of Li2CdGeS4 viewed down the c-axis (a) and b-axis (b). Adapted and reprinted with permission from ref [62], Copyright 2009 American Chemical Society. Samples of Li2CdGeS4 and Li2CdSnS4 exhibit SHG response of approximately 70 and 100 times that of α-quartz, i.e., 0.5 and 0.7 times that of AGS, respectively.62 The SHG signals are relatively weak. But in the latest experiment, Li2CdGeS4 showed a high SHG response comparable to benchmark materials AGS and the absolute dij value of crystal is estimated to be 25.8 pm/V at 3.3 µm.61 The particle-size-dependent SHG experiment indicates that Li2CdGeS4 is phase-matchable at λ > 1.5 µm. More importantly, Li2CdGeS4 and Li2CdSnS4 compounds are found to have the bandgaps of 3.10 eV and 3.26 eV,62 respectively, larger than commercial AGS (2.70 eV), implying that they would have higher LDT value.

Table 8. Experimental and calculated Eg, dij, and ∆n of normal DL compounds compounds Space Eg(exp) SHG efficiency calculated group (pm/V) Binary normal DL compounds α-ZnS165, 209 F-43m 3.60 d36=10.25 d36=15.29 (static) β-ZnS165, 209

P63mc

∆n(cal) 0 (0.000) 0.003 (@2090 nm) 0.004 (@2000nm)a

d33=9.51

d33=-12.35(static)

Tenary normal DL compounds I-III-VI2 AgGaS214-15, 164 I-42d 2.78

d36=13

d36=14.1(static)

AgGaSe214-15, 164

I-42d

1.83

d36=33

d36=45.2(static)

AgGaTe214-15, 164

I-42d

1.36

d36=51

d36=99(static)

LiGaS215, 215-216

Pna21

4.15

d31=-5.8;d32=-5.1; d33=10.7

LiGaSe215, 215-216

Pna21

3.57

d31=-10;d32=-7.7; d33=18.20

LiGaTe2216-217

I-42d

2.31

d36=34.5

d31=-6.1; d32=-5.51; d33=12.86(static) d31=-10.2;d32=-9.67; d33=23.97(static) d36=-50.4(static)

Cc

1.98

No data

d33=36(static)

0.09 (static)

Pmn21

3.68

No data

d15=-3.08;d24=-4.03; d33=4.32(static)

0.044(@ 2090 nm)

70×SiO2 (@1064nm)

d15=2.27;d24=3.57; d31=2.13;d32=1.96; d33=7.64(static) d15=2.22;d24=2.85; d31=0.96;d32=0.96; d33=4.78(static) d33=-10.06(static)

0.009 (static) 0.023 (@2090 nm)

I2-IV-VI3 Ag2GeS3165, 218 I3-V-VI4 Li3PS417, 165

3.49

dij

Quaternary normal DL compounds wurtz-stannite Li2CdGeS462, 165, Pmn21 3.10 219

Li2CdSnS462,

165,

Pmn21

3.26

100×SiO2 (@1064nm)

Pmn21

3.00

dij=7.5±1 (@1064nm,125-150µm)

219

α-Cu2ZnSiS4165, 213

lithium cobalt (II) silicate


0.031(@1064 nm) 0.053(@1000nm)a 0.044(@1064 nm) 0.020(@1000nm)a 0.011(@1064 nm) 0.016(@1000nm)a 0.014(@2090 nm) 0.040(@2000nm)a 0.016 (@2090 nm) 0.050(@2000nm)a 0.032 (@2090 nm) 0.094 (@5.3 µm)a

0.009 (static) 0.018 (@2090 nm) 0.052 (@2090 nm)


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Li2MnGeS4165, 214

Pna21

3.06

α-Li2MnSnS4165,

Pna21

2.6-3.0

dij =7.5±2.5 (@1064nm,125-150µm) 2%×AGSe (@1064µm)

d33=9.92 (static)

0.010 (@2090 nm)

d33=6.25 (static)

0.011 (@2090 nm)

Pn

3.20

dij =7.5±1 (@1064nm,125-150µm) 2%×AGSe (@1064µm) dij =21.6 (@2100nm,125-150µm) dij =26.1 (@2100nm,125-150µm)

d11=12.02 (static)

0.035 (@2090 nm)

β-Li2MnSnS4212 Li2ZnGeSe4220

Pn Pn

2.6-3.0 1.86

Li2ZnSnSe4220

Pn

1.87

Stannite Cu2CdSnS4165, 213

I-42m

0.92

dij =31±3.5 (@2600nm,90-106 µm)

d36=-25.42 (static)

0.134 (@2090 nm)

I4-II-IV2-VI7 Li4HgGe2S7221

Cc

2.75

1.5×AGS (@2090µm, 200-250µm)

d11=5.77;d15=13.62; d12=-8.08; d13=10.42; d24=-7.86;d33=-14.36; (static)

-

212

wurtz–kesterite β-Cu2ZnSiS4165, 213

a

Page 28 of 38

-

-

-

-

experimental results

(ii) Lithium cobalt (II) silicate In Li2MnGeS4 structure, each cation coordinates to four tetrahedral sulfide anions, and all of the tetrahedra align along the c axis, rendering the NCS structure (Figure 51).214 Li2MnGeS4 is assigned as a direct-gap semiconductor, yielding a bandgap of 3.06 eV. Taking AGSe as a reference, Li2MnGeS4 exhibit moderate SHG effect with dij =7.5 ± 2.5 pm/V.214

Figure 51. Crystal structure of Li2MnGeS4 viewed down the c-axis (a) and a-axis (b). green tetrahedra: [LiS4]; blue tetrahedra: [MnS4]; red tetrahedra: [GeS4]. Adapted and reprinted with permission from ref [214], Copyright 2015 American Chemical Society. (iii) Wurtz-kesterite Li2ZnGeSe4 and Li2ZnSnSe4 crystallize in the NCS space group Pn and all of the tetrahedra align along the a axis (Figure 52).220 The SHG response of compounds is also comparable to AGSe under the same condition.220 The dij values for Li2ZnGeSe4 and Li2ZnSnSe4 are approximately 9.5 pm/V and 11.5 pm/V, respectively. The measured bandgap is only 1.86 eV, implying a low LDT, which is inconvenient for many practical applications.

Figure 52. Crystal structure of Li2ZnGeSe4 viewed down the (a) a-axis and (b) b-axis. Adapted and reprinted with

permission from ref [220], Copyright 2015 Royal Society of Chemistry.

Figure 53. Pyramidal graph of normal DL compounds constructed from single-element DL structure to multi-element DL structures. In addition to the normal DL compounds mentioned above, α/β-Cu2ZnSiS4,213 Cu2CdSnS4213 and α/β-Li2MnSnS4212 are also reported to be SHG active. The properties of the normal DL metal chalcogenides in this subsection are listed in Table 8. As Pamplin pointed in 1981,222 “there are a thousand adamantine phases (i.e., DL structures) from which to choose device material”. The diversity of the DL compounds presents not only in the variety of many stoichiometric ratios, but also in many possibilities of choice for the [MQ4] microscopic building blocks. Hence, there must exist plenty space for the explorations of good mid-IR NLO materials in the DL metal chalcogenides, as demonstrated by pyramidal graph of normal DL structures plotted in Figure 53. Very recently, quaternary sulfide DL compound Li4HgGe2S7 has been reported to exhibit excellent performances with concurrently large NLO coefficients and impressive LDT, which satisfy the essential requirements of mid-IR NLO candidates.221 The perspective of normal diamond-like structures has been analyzed in details in our previous work.165 2.7.2 Defect diamond like (DL) structure metal chalcogenides


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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


The defect DL structure is a variation of the normal DL structure in which some chalcogen anions have less than four neighbor atoms. Because of the existence of cations deficiency, the defect DL metal chalcogenides have relatively looser 3D structure compared with the normal structures. Taken the ternary metal sulfide HgGa2S4 as an example, it can be considered that half of the Ag+ sites in the AgGaS2 structure are replaced by Hg2+ cations while the other half of the Ag+ sites keep void (Figure 54). HgGa2S4 possesses a rather wide bandgap of 2.84 eV and a very large SHG effect which is about three times larger than that of AgGaS2.223-224 In addition, this material has moderate optical anisotropy with a uniaxial birefringence of 0.054.224 Analogous to the normal DL metal sulfides, we divide the defect DL structures into three categories: binary, ternary and quarternary defect DL structures, including Ga2S3, Zn3(PS4)2, InPS4, LiZnPS4, and AgZnPS4 etc.

Binary defect DL chalcogenides The most known binary defect DL chalcogenide is Ga2S3. There are two phases of Ga2S3 with different space groups F-43m (α-phase) and Cc (β-phase).225-226 α-Ga2S3 adopts sphalerite structure and every Ga3+ cation is partially occupied (66.7%) (Figure crystal contains 55a). In comparison, β-Ga2S3 corner-shared [GaS4]3- tetrahedra and S atoms are hexagonal closest-packing (Figure 55b). They exhibit comparatively large SHG effects of about 0.5 and 0.7 times that of KTP, for α-Ga2S3 and β-Ga2S3 respectively, in which the former is non-phase matchable and the latter is phase matchable under 1910 nm. In addition, both phases of Ga2S3 possess close optical band gaps of about 2.80 eV,225 which are consistent with their yellow color. All these properties make them very promising practical mid-IR NLO materials.

Figure 55. Crystal structure of (a) α-Ga2S3 and (b) β-Ga2S3 Ternary defect DL chalcogenides Here we choose Zn3(PS4)2 and InPS4 as the representative to describe the structures and NLO performance in this type of chalcogenides. Figure 54. Crystal structure of (a) HgGa2S4 and (b) AgGaS2 Table 9. Experimental and calculated Eg, dij, and ∆n of defect DL structures compounds Space Eg SHG efficiency calculated dij (pm/V) group (exp) α-Ga2S3225 F-43m 2.80 d14=20.32 (@1910nm) 0.5×KTP (@1910nm,50-75µm) β-Ga2S3225 Cc 2.80 d11=28.18;d12=14.34; 0.7×KTP d13=24.87;d15=7.06; (@1910nm,50-75µm) d24=15.26;d33=7.61 (@1910 nm) HgGa2S4224, 227 I-4 2.84 d36=31.5;d31=10.4 (@1064 d36=25.15 (static) nm) Zn3(PS4)217

P-4n2

3.07

InPS417, 228

I-4

3.12

LiZnPS417

I-4

3.44

AgZnPS4229

Pna21

2.76

1.6×AGS (@2090nm,105-150µm) d31=36;d36=28

d15=-d24=16.28 (static)

0.8×AGS (@2090nm,105-150µm) 1.8×AGS (@2090nm,105-150µm)

d15=-d24=0.89; d14=10.42 (static) d15=10.10;d24=9.19; d33=−17.04 (static)

d15=13.98;d14=15.12 (static)

∆n (cal) 0.000 0.025 (static)

0.078(@2090 nm) 0.045(@1076 nm)a 0.036(@2090 nm) 0.023(@2090 nm) 0.048(@1064nm) a

a

0.072(@2090 nm) 0.051(@2090 nm)

experimental results

(i) Zn3(PS4)2 Zn3(PS4)2 crystallizes in P-4n2 space group230 and has a unique valance electron concentration number equal to 4.92 in all known metal thisophosphates. As displayed in Figure 56a, the [PS4]5- tetrahedra are arranged within cubic closest-packing and the Zn2+ cations are located in three quarters of the tetrahedral voids, forming the corner-sharing [ZnS4]6- tetrahedra. The calculated bandgap of Zn3(PS4)2 is 3.19 eV, which is consistent with experimental results (3.07 eV). In addition,

the SHG response of Zn3(PS4)2 is 1.6 times of that AGS.17 Therefore, Zn3(PS4)2 is a good candidate for mid-IR NLO application. (ii) InPS4 InPS4 is isostructural to a UV NLO material BPO4 and belongs to I-4 space group.228 As plotted in Figure 56b, This compound has a 3D framework that consists of corner-sharing [InS4]5- and [PS4]3- tetrahedra. InPS4 has been studied in detail as a promising mid-IR NLO material since the 1980s. The measured SHG coefficient



1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

dij~25 pm/V and birefringence ∆n =0.048, which are comparable to those of AGS.228 More importantly, the bandgap of InPS4 is 3.12 eV, larger than that of AGS, suggesting a higher LDT value.

Figure 56. Crystal structure of (a) LiZnPS4 and (b) AgZnPS4. Quarternary defect DL chalcogenides In fact, the number of quaternary defect DL structures is scarce, and only four compounds, i.e., LiZnPS4,230 AgZnPS4,231 CuHgPS4,232 and CuInGeS4233 have been synthesized. Since the latter two compounds have disordered structures, LiZnPS4 and AgZnPS4 are selected to discuss the optical properties in quaternary defect DL compounds. LiZnPS4 and AgZnPS4 LiZnPS4 and AgZnPS4 have a similar 3D framework and defect concentration just like HgGa2S4.230-231 The only difference between two compounds is that S atoms are cubic closest-packing and hexagonal closest-packing in LiZnPS4 and AgZnPS4, respectively (Figure 56c and 56d). Theoretical calculations showed that these two compounds have large bandgap (>3.0 eV), high SHG coefficient (~1×AGS) and moderate birefringence (0.05-0.08), suggesting that they might be the promising materials for practical mid-IR NLO applications. This conclusion has also been confirmed by the recent experiments.17, 229 Table 9 lists the details of linear and nonlinear optical properties for the mentioned defect DL metal chalcogenides. Clearly, quite a few compounds satisfy the key balance of a good IR NLO materials (Eg> 3.0 eV and dij> 13 pm/V), in which HgGa2S4 and InPS4 have been demonstrated to exhibit superior NLO performance in IR region.170 In addition, the moderate birefringence is also favourable to achieve phase matchable in practical applications. Accordingly, defect DL metal chalcogenides might be the good candidates for mid-IR NLO crystals. Considering the situation that the defect DL metal sulfides have not been widely concerned, it may be reasonably predicted that there would exist many superior mid-IR NLO materials in this system.165

Page 30 of 38

been reported and here the recent developments are summarized in this aspect. Ba3AGa5Se10Cl2 (A=K, Rb, Cs) Ba3AGa5Se10Cl2 (A = K, Rb and Cs) represent a new type of NCS structure that is constructed by supertetrahedral clusters in the tetragonal space group I-4.66 It features the supertetrahedral [Ga4Se10]8− cluster (T2) and tetrahedron [GaSe4]5− (T1). The 3D anionic covalent framework of [Ga5Se10]5− is interpenetrated by Ba2+/Cs+ cations and Cl− anions (Figure 57). The optical band gaps for K, Rb and Cs-compounds are approximately 2.04 eV, 2.05 eV, and 2.08 eV, respectively, as reported in 2012.66 Meanwhile, these compounds were measured to exhibit a very strong SHG effect large up to 100×AGS.66 However, In 2015, the bandgaps of these three compounds were re-determined to be 3.22 eV, 3.23 eV and 3.25 eV, respectively.235 The corrected SHG coefficients of Ba3CsGa5Se10Cl2 were d14=12.86 and d15=10.84 pm/V (@2050 nm), which is comparable with AGS. However, the birefringence values (∆n) are found to be very small, 0.007, 0.006, and 0.011 for K, Rb and Cs-compounds,66 which are not suitable for achieving the phase-matching condition.

Figure 57. Crystal structure of Ba3CsGa5Se10Cl2. Light blue: Cl-; dark blue: Cs+/Ba2+; Red: T1 tetrahedron [GaSe4]5−; green: T2 supertetrahedral cluster [Ga4Se10]8−. Adapted and reprinted with permission from ref [66], Copyright 2012 American Chemical Society. Ba4MGa4Se10Cl2 (M=Zn, Cd, Mn, Cu/Ga, Co, Fe) Compounds Ba4MGa4Se10Cl2 are analog of Ba3CsGa5Se10Cl2.235 It features a 3D network that is constructed by supertetrahedral [Ga4Se10]8- T2 clusters with simple [MSe4] T1 tetrahedra. Such an open network is characterized by channels that accommodate the counter Ba2+ cations and Cl− anions (Figure 58). The optical bandgaps of Ba4MGa4Se10Cl2 were measured to be approximately 3.08–1.88 eV (Table 10).235 In addition, the SHG responses of Zn-, Cd-, and Mn-compounds are about 59, 52 and 30 times that of AGS in the particle size of 30−46 µm. Nevertheless, the calculated birefringence values (∆n) for all compounds are smaller than 0.01, indicating their non-phase-matchable behaviors, which is consistent with experimental observations.235

2.8 Metal chalcogenides containing halogen elements Halide IR NLO materials usually possess large band gaps (3.3 eV, 4.3 eV and 5.0 eV for HgBr2, SbF3 and NaSb3F10, respectively)25, 27, 234 and high LDTs (1.3 and 0.3 GW/cm2 for NaSb3F10 and HgBr2, respectively),25, 27 but their NLO responses are usually much smaller than those of chalcogenides.30 Therefore, if one could incorporate the advantages of chalcogenides (large NLO response) and those of halides (large bandgap and laser damage threshold) into one compound, the resulted material would be possible to have superior mid-IR NLO performance. Up to now, a few works about mixed chalcogen-halogen compounds has


Page 31 of 38

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Crystal Growth & Design which Ba4Ge3S9Cl2 exhibits stronger SHG response than that of AGS.236

Figure 58. (a) Crystal structure of Ba4MGa4Se10Cl2. (b) The static polarizations of [Ga4Se10]8- (T2) and [MSe4] (T1) clusters are zero because that of each individual tetrahedron is cancelled by symmetry operation. Adapted and reprinted with permission from ref [235], Copyright 2015 John Wiley. NaBa4Ge3S10Cl NaBa4Ge3S10Cl crystallizes in the hexagonal space group P63.32 In its structure (Figure 59a), each Ge atom is connected to four S atoms with distorted tetrahedral geometry, and three such [GeS4]4- tetrahedra are further linked by sharing corner S atoms to generate the isolated [Ge3S9]6- ring (Figure 59b). The Na atoms are connected to S and Cl atoms to generate trigonal bipyramids [NaS3Cl2]7- with the two Cl atoms as the apices. The Ba1 atom is coordinated to seven S atoms and one Cl atom while the Ba2 atom is linked by seven S atoms (Figure 59c). The absorption edge of NaBa4Ge3S10Cl is 355 nm, corresponding to the band gap of 3.49 eV.32 It shows a moderate NLO response about one third of that of AGS, which agree well with calculated dpowder = 3.44 pm/V.32 It is noted that the [Ge3S9]6- rings are aligned in almost the same direction in a single pseudo-layer, which should generate a strong NLO response. However, two adjacent pseudo-layers are related by the 63 screw axis, thus the orientations of the [Ge3S9]6- rings are rotated by 60° and only the polar arrangement of the Ge–S2 bonds is maintained, which reduces the overall macroscopic NLO effect. Very recently, three novel quaternary compounds, Ba4Ge3S9Cl2, Ba4Si3Se9Cl2 and Ba4Ge3Se9Cl2, have been synthesized by a rational tailored approach on the basis of NaBa4Ge3S10Cl, in

Figure 59. (a) Crystal structure of NaBa4Ge3S10Cl. the coordination environments of (b) Ge atoms and (c) Na+ and Ba2+ cations in NaBa4Ge3S10Cl. Adapted and reprinted with permission from ref [32], Copyright 2014 Royal Society of Chemistry. [A3X][Ga3PS8](A=K, Rb; X=Cl, Br) In this series of compounds, all of them feature a 2D structure constructed from polar stacking of DL [Ga3PS10]6- clusters and A+/Xions are located in interlayer spaces.67 Every [Ga3PS10]6cluster consists of three corner-sharing [GaS4]5- tetrahedra in ab plane and a capping [PS4]3- tetrahedron along c direction (Figure 60a and 60d). The cationic [A3X]2+ layers can be considered as formed by the distorted X-centered quadrangular pyramids, [XA5]4+, which are corner-shared with each other along the a and b-directions (Figure 60c and 60f). Interestingly, despite of same stoichiometric ratio, the Cl-analogues and the Br-analogues crystallize in different space groups Pmn21 and Pm, respectively (Figure 60b and 60e). In the Br-analogues, the neighboring [Ga3PS10]6- cluster layers stack along the c-direction without a transversal shift in the ab-plane. In comparison, in the Cl-analogues the neighboring [Ga3PS10]6cluster layers are stacked with a slightly shift along the a-axis and the b-axis, which results in the doubling of the c parameter of unit cell. Differential scanning calorimetry (DSC) measurements show that these four compounds are congruently melting at a relatively low temperature (Tm < 700 °C), so the large crystal could be grown using the Bridgman method. The bandgaps of them are large up to 3.60 eV, 3.65 eV, 3.85 eV, and 3.50 eV, respectively,67 which is much larger than AGS. Moreover, these compounds also show strong SHG response, about 1.0, 1.1, 1.2 and 2.0 times that of AGS at 1950 nm.67 Therefore, this series of compounds are potentially superior candidates for mid-IR NLO materials and more efforts should be performed to grow large bulk single crystals.

Table 10. Experimental and calculated Eg, dij, and ∆n in the metal chalcogenides contain halogen elements. compounds Space Eg(exp) SHG efficiency calculated dij (pm/V) group Ba3KGa5Se10Cl266, 235 I-4 2.04, d14=73.2;d15=39.3; 10×AGS (@2050nm,30-46µm) 3.22 (@2050nm) Ba3RbGa5Se10Cl266, 235 I-4 2.05, d14=72.5;d15=46.5; 20×AGS (@2050nm,30-46µm) 3.23 (@2050nm) Ba3CsGa5Se10Cl266, 235 I-4 2.08, d14=69.8;d15=47.6;d14=12.8; 100×AGS (@2050nm,30-46µm) 3.25 d15=10.8;(@2050nm) Ba4ZnGa4Se10Cl2235 I-4 3.08 d14=16.2;d15=12.9; 59×AGS (@2050nm,30-46µm) (@2050nm) Ba4CdGa4Se10Cl2235 I-4 2.93 d14=21.3;d15=9.01; 52×AGS (@2050nm,30-46µm) (@2050nm) Ba4MnGa4Se10Cl2235 I-4 2.78 30×AGS (@2050nm,30-46µm)


∆n(cal) 0.011 (static) 0.006 (static) 0.007 (static) 0.002 (static) 0.004 (static) -


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Ba4Cu0.5Ga4.5Se10Cl2235 Ba3CsInGa4Se10Cl2237 Ba6Cs2InGa9Se20Cl4237 NaBa4Ge3S10Cl32 Ba4Ge3S9Cl2236

I-4 I-4 I-4 P63 P63

2.54 2.90 3.01 3.49 2.91

39×AGS (@2050nm,30-46µm) 70×AGS (@2050nm,30-46µm) 64×AGS (@2050nm,30-46µm) 1/3×AGS (@2090nm,100µm) 2.4×AGS (@2050nm,46-74µm)

Ba4Si3Se9Cl2236 Ba4Ge3Se9Cl2236 [K3Cl][Ga3PS8]67

P63 P63 Pmn21

1.76 1.89 3.60

[Rb3Cl][Ga3PS8]67

Pmn21

3.65

[K3Br][Ga3PS8]67

Pm

3.85

weak signal weak signal 4.0×AGS (@1064nm,200-250µm) 1.0×AGS (@1950nm,200-250µm) 5.0×AGS (@1064nm,200-250µm) 1.1×AGS (@1950nm,200-250µm) 7.0×AGS (@1064nm,200-250µm) 1.2×AGS (@1950nm,200-250µm)

[Rb3Br][Ga3PS8]67

Pm

3.50

9.0×AGS (@1064nm,200-250µm) 2.0×AGS (@1950nm,200-250µm)

(Sb7S8Br2)(AlCl4)3238 LaCa2GeS4Cl3239 Hg3AsE4X240 (E=S, Se; X=Cl, Br, I)

P212121 P63mc P63mc

2.03 -

1.0×KDP (@1800nm,45-63µm) SHG active (@1064nm) SHG active (@1064nm)

Figure 60. Crystal structure of [A3X][Ga3PS8](A=K, Rb; X=Cl, Br). The [Ga3PS10]6- cluster layers in Cl-compounds (a) and Br-compounds (d), cationic [A3X]2+ layers in Cl-compounds (c) and Br-compounds (f), and an overview of the 3D frameworks in Cl-compounds (b) and Br-compounds (e). Adapted and reprinted with permission from ref [67], Copyright 2016 Royal Society of Chemistry. Table 10 lists the key NLO parameters for the metal chalcogenides containing halogen elements discussed in this section. Up to now, the research on mixed halogen and chalcogen elements is relatively scarce. In addition to the four series compounds mentioned above, the LaCa2GeS4Cl3,239 and Hg3AsE4X (E=S, Se; X=Cl, Br, I)240 compounds are also SHG active. Mixed chalcogen-halogen compounds can integrate the advantages of chalcogenides (large SHG coefficient) and (Cl/Br)-halides (large bandgap and high LDT) into one compound, which may provide new opportunity to design new superior mid-IR NLO materials. 3. Conclusions and outlook In summary, we have reviewed the recent development of metal chalcogenides, focusing on abundant chemical composition, flexible structure and rich building units, especially their promising applications as mid-IR NLO materials. The triangle planar units, tetrahedral units, SALP units, SOJT units, rare-earth units and halogen atoms afford many opportunities for exploring new NLO materials. Based on our analysis and discussions, some general rules could be concluded:

Page 32 of 38 d33=6.81;d15=-2.72 (static) d33=20.02;d15=33.63 (@2050nm) d15=26.7;d24=26.1;d33=26.5 (@1064nm) d15=30.7;d24=30.3;d33=29.8 (@1064nm) d11=45.2;d12=45.3; d13=44.1; d15=44.6;d24=45.0;d33=43.6 (@1064nm) d11=50.9;d12=50.2; d13=49.2; d15=50.1;d24=49.7;d33=48.5 (@1064nm) -

0.019 (static) -

(i) Metal chalcogenides have wide IR transparent regions (usually beyond 11 µm) than oxides because of the lower bond stretching frequency, so they are inherently favourable for IR applications. (ii) From S, Se to Te, the chalcogen atom is more and more polarizable. As a result, the bandgap of compounds usually decrease, while SHG effect and birefringence increase significantly. (iii) The introduction of SALP or SOJT effect cations would improve the structural anisotropy, resulting strong SHG response and large birefringence. However, it has a negative influence on the bandgap enlargement of metal chalcogenides. (iv) The introduction of the rare-earth elements would narrow the bandgap considerably. But it can provide an opportunity to find new functional materials, such as luminescent material and magnetic material. (v) The introduction of the halogen elements (especially chlorine anions) would enlarge the bandgap of metal chalcogenides. Meanwhile, it maintains the advantages of chalcogenide compounds (large NLO response), so this is a very promising direction for developing new IR NLO materials. (vi) Polar aligned DL structure (including normal and defect DL structures) is the most favorable system for mid-IR NLO crystal owing to its large bandgap, sufficient SHG effect and moderate birefringence. Besides, large size crystals may be grown easily due to its stable closest packing anion sublattice. For the future development of IR NLO materials, the researchers should focus on the following aspects: (i) Searching new SHG active building units. For example, triangle planar units [MQ3], aligned supertetrahedra (such as [Ga4Se10]8- in Ba3CsGa5Se10Cl2 and [Ga3PS10]6- in [K3Cl][Ga3PS8]) and possible mixed [MQmXn] anion units (such as [Ge4S6Br4] in Ge4S6Br4).241 These may also lead to new NLO crystals with rich structural and compositional diversity. (ii) Growing large size crystal. Though many metal chalcogenides possess excellent SHG properties, the large size crystals for practical applications have not been obtained. Therefore, the priority should be given to the compounds which are melting congruently, since they can be grown by Bridgman-Stockbarger technique. In addition, many important physical measurements require large size crystals, including IR absorption edge, LDT value and SHG tensor component and so on. In fact, almost all optical properties in this review were measured by powder samples,


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and the re-determination based on the large size crystals are necessary for eventually evaluating the practical application prospect of NLO materials. (iii) Developing metal chalcogenides with multi functions. Besides SHG properties, polar chalcogenides may also display piezoelectricity, pyroelectricity and ferroelectricity. The introduction of magnetic centers may also provide ferromagnetic properties and magnetoelectric modulation. Furthermore, thermoelectric properties can also be measured for those narrow bandgap, heavy elements enrichment metal chalcogenides. Doping of luminescent rare-earth ions into the SHG active structures may also lead to luminescence and self-frequency doubling (SFD) laser materials. (iv) Exploring the relationship between structure and properties in mid-IR NLO materials. Without doubt, the elucidation of the relationship can significantly prompt the discovery of superior mid-IR NLO metal chalcogenides. Up to now, the studies on this aspect have made great progress. The SHG effects, bandgaps and refractive indices can be determined from the atomic structures in metal chalcogenides. However, it is still unclear how the microscopic structures accurately affect the IR absorption edges, birefringence dispersion and LDT values. Especially, the latter two properties may play a crucial role for achieving the high-power harmonic output. We believe the first-principles calculations, combined with experimental measurements, will play an important role in this aspect.

AUTHOR INFORMATION Corresponding Author *E-mail: [email protected]

Notes The authors declare no competing financial interest.

ACKNOWLEDGMENT This work was supported by China “863” project (No. 2015AA034203) and the National Natural Science Foundation of China under Grant Nos. 11174297.

REFERENCES (1) Petrov, V., Prog. Quantum Electron. 2015, 42, 1-106. (2) Chen, C. T.; Wu, B. C.; Jiang, A. D.; You, G. M., Sci. Sin. Ser. B 1985, 28, 235-243. (3) Chen, C. T.; Wu, Y. C.; Jiang, A. D.; Wu, B. C.; You, G. M.; Li, R. K.; Lin, S. J., J. Opt. Soc. Am. B-Opt. Phys. 1989, 6, 616-621. (4) Boyd, G. D.; Nassau, K.; Miller, R. C.; Bond, W. L.; Savage, A., Appl. Phys. Lett. 1964, 5, 234-236. (5) Haussuhl, S., Z. Kristallogr. 1964, 120, 401-414. (6) Bierlein, J. D.; Vanherzeele, H., J. Opt. Soc. Am. B-Opt. Phys. 1989, 6, 622-633. (7) Wang, L. S.; Cao, Z. S.; Wang, H.; Zhao, H.; Gao, W.; Yuan, Y. D.; Chen, W. D.; Zhang, W. J.; Wang, Y. J.; Gao, X. M., Opt. Commun. 2011, 284, 358-362. (8) Chernov, A. A.; Zaitseva, N. P.; Rashkovich, L. N., J. Cryst. Growth 1990, 102, 793-800. (9) Zhou, Y.; Wang, G. L.; Li, C. M.; Peng, Q. J.; Cui, D. F.; Xu, Z. Y.; Wang, X. Y.; Zhu, Y.; Chen, C. T.; Liu, G. D.; Dong, X. L.; Zhou, X. J., Chin. Phys. Lett. 2008, 25, 963-965. (10) Willer, U.; Saraji, M.; Khorsandi, A.; Geiser, P.; Schade, W., Opt. Lasers Eng. 2006, 44, 699-710. (11) Pestov, D.; Wang, X.; Ariunbold, G. O.; Murawski, R. K.; Sautenkov, V. A.; Dogariu, A.; Sokolov, A. V.; Scully, M. O., PNAS 2008, 105, 422-427.

(12) Pushkarsky, M.; Tsekoun, A.; Dunayevskiy, I. G.; Go, R.; Patel, C. K. N., PNAS 2006, 103, 10846-10849. (13) Pushkarsky, M. B.; Dunayevskiy, I. G.; Prasanna, M.; Tsekoun, A. G.; Go, R.; Patel, C. K. N., PNAS 2006, 103, 19630-19634. (14) Ohmer, M. C.; Pandey, R.; Bairamov, B. H., MRS Bull. 1998, 23, 16-20. (15) David N. Nikogosyan; Nonlinear Optical Crystals: A Complete Survey, Springer Press, 2005 (16) Schunemann, P. G., Crystal growth and properties of nonlinear optical materials. In Perspectives on Inorganic, Organic, and Biological Crystal Growth: From Fundamentals to Applications. 2007; 916, 541-559. (17) Kang, L.; Zhou, M. L.; Yao, J. Y.; Lin, Z. S.; Wu, Y. C.; Chen, C. T., J. Am. Chem. Soc. 2015, 137, 13049-13059. (18) Jackson, A. G.; Ohmer, M. C.; LeClair, S. R., Infrared. Phys. Techn. 1997, 38, 233-244. (19) Zhang, W. G.; Tao, X. T.; Zhang, C. Q.; Gao, Z. L.; Zhang, Y. Z.; Yu, W. T.; Cheng, X. F.; Liu, X. S.; Jiang, M. H., Cryst. Growth. Des 2008, 8, 304-307. (20) Takahashi, Y.; Onduka, S.; Brahadeeswaran, S.; Yoshimura, M.; Mori, Y.; Sasaki, T., Opt. Mater. 2007, 30, 116-118. (21) Dalton, L. R.; Sullivan, P. A.; Bale, D. H., Chem. Rev. 2010, 110, 25-55. (22) Sullivan, P. A.; Dalton, L. R., Acc. Chem. Res. 2010, 43, 10-18. (23) Pan, F.; Wong, M. S.; Bosshard, C.; Gunter, P., Adv. Mater. 1996, 8, 592-595. (24) Yang, Z.; Mutter, L.; Stillhart, M.; Ruiz, B.; Aravazhi, S.; Jazbinsek, M.; Schneider, A.; Gramlich, V.; Guenter, P., Adv. Funct. Mater. 2007, 17, 2018-2023. (25) Zhang, G.; Qin, J. G.; Liu, T.; Li, Y. J.; Wu, Y. C.; Chen, C. T., Appl. Phys. Lett. 2009, 95, 261104. (26) Zhang, J.; Su, N. B.; Yang, C. L.; Qin, J. G.; Ye, N.; Wu, B. C.; Chen, C. T. Electro-Optic and 2nd Harmonic Generation Materials, Devices, and Applications II, Beijing, Peoples R China, 1998Sep 18-19; Beijing, Peoples R China, 1998, 3556, 1-3. (27) Liu, T.; Qin, J.; Zhang, G.; Zhu, T.; Niu, F.; Wu, Y.; Chen, C., Appl. Phys. Lett. 2008, 93, 091102. (28) Wu, Q.; Meng, X. G.; Zhong, C.; Chen, X. G.; Qin, J. G., J. Am. Chem. Soc. 2014, 136, 5683-5686. (29) Lin, Z. G.; Tang, L. C.; Chou, C. P., Opt. Mater. 2008, 31, 28-34. (30) Kang, L.; Ramo, D. M.; Lin, Z. S.; Bristowe, P. D.; Qin, J. G.; Chen, C. T., J. Mater. Chem. C 2013, 1, 7363-7370. (31) Wu, Q.; Liu, H. M.; Jiang, F. C.; Kang, L.; Yang, L.; Lin, Z. S.; Hu, Z. G.; Chen, X. G.; Meng, X. G.; Qin, J. G., Chem. Mater. 2016, 28, 1413-1418. (32) Feng, K.; Kang, L.; Lin, Z. S.; Yao, J. Y.; Wu, Y. C., J. Mater. Chem. C 2014, 2, 4590-4596. (33) Boyd, G. D.; Buehler, E.; Storz, F. G., Appl. Phys. Lett. 1971, 18, 301-304. (34) Zawilski, K. T.; Schunemann, P. G.; Pollak, T. C.; Zelmon, D. E.; Fernelius, N. C.; Hopkins, F. K., J. Cryst. Growth 2010, 312, 1127-1132. (35) Zhang, G. D.; Ruan, H. P.; Zhang, X.; Wang, S. P.; Tao, X. T., Crystengcomm 2013, 15, 4255-4260. (36) Zhang, G. D.; Tao, X. T.; Ruan, H. P.; Wang, S. P.; Shi, Q., J. Cryst. Growth 2012, 340, 197-201. (37) Lin, X. S.; Zhang, G.; Ye, N., Cryst. Growth. Des 2009, 9, 1186-1189. (38) Yao, J. Y.; Mei, D. J.; Bai, L.; Lin, Z. S.; Yin, W. L.; Fu, P. Z.; Wu, Y. C., Inorg. Chem. 2010, 49, 9212-9216. (39) Kim, Y.; Seo, I.-S.; Martin, S. W.; Baek, J.; Halasyamani, P. S.; Arumugam, N.; Steinfink, H., Chem. Mater. 2008, 20, 6048-6052.


33


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

(40) Isaenko, L. I.; Yelisseyev, A. P.; Lobanov, S. I.; Krinitsin, P. G.; Molokeev, M. S., Opt. Mater. 2015, 47, 413-419. (41) Mei, D. J.; Yin, W. L.; Feng, K.; Lin, Z. S.; Bai, L.; Yao, J. Y.; Wu, Y. C., Inorg. Chem. 2012, 51, 1035-1040. (42) Yelisseyev, A. P.; Isaenko, L. I.; Krinitsin, P.; Liang, F.; Goloshumova, A. A.; Naumov, D. Y.; Lin, Z. S., Inorg. Chem. 2016, 55, 8672-8680. (43) Yin, W. L.; Feng, K.; He, R.; Mei, D. J.; Lin, Z. S.; Yao, J. Y.; Wu, Y. C., Dalton Trans. 2012, 41, 5653-5661. (44) Lin, X. S.; Guo, Y. F.; Ye, N., J. Solid State Chem. 2012, 195, 172-177. (45) Chung, I.; Do, J.; Canlas, C. G.; Weliky, D. P.; Kanatzidis, M. G., Inorg. Chem. 2004, 43, 2762-2764. (46) Chung, I.; Jang, J. I.; Malliakas, C. D.; Ketterson, J. B.; Kanatzidis, M. G., J. Am. Chem. Soc. 2010, 132, 384-389. (47) Chung, I.; Kim, M.-G.; Jang, J. I.; He, J.; Ketterson, J. B.; Kanatzidis, M. G., Angew. Chem. Int. Edit. 2011, 50, 10867-10870. (48) Haynes, A. S.; Saouma, F. O.; Otieno, C. O.; Clark, D. J.; Shoemaker, D. P.; Jang, J. I.; Kanatzidis, M. G., Chem. Mater. 2015, 27, 1837-1846. (49) Jang, J. I.; Haynes, A. S.; Saouma, F. O.; Otieno, C. O.; Kanatzidis, M. G., Opt. Mater. Express 2013, 3, 1302-1312. (50) Chung, I.; Malliakas, C. D.; Jang, J. I.; Canlas, C. G.; Weliky, D. P.; Kanatzidis, M. G., J. Am. Chem. Soc. 2007, 129, 14996-15006. (51) Chen, M. C.; Wu, L. M.; Lin, H.; Zhou, L. J.; Chen, L., J. Am. Chem. Soc. 2012, 134, 6058-6060. (52) Bera, T. K.; Jang, J. I.; Song, J.-H.; Malliakas, C. D.; Freeman, A. J.; Ketterson, J. B.; Kanatzidis, M. G., J. Am. Chem. Soc. 2010, 132, 3484-3495. (53) Chung, I.; Song, J.-H.; Jang, J. I.; Freeman, A. J.; Kanatzidis, M. G., J. Solid State Chem. 2012, 195, 161-165. (54) Bera, T. K.; Song, J.-H.; Freeman, A. J.; Jang, J. I.; Ketterson, J. B.; Kanatzidis, M. G., Angew. Chem. Int. Edit. 2008, 47, 7828-7832. (55) Bera, T. K.; Jang, J. I.; Ketterson, J. B.; Kanatzidis, M. G., J. Am. Chem. Soc. 2009, 131, 75-77. (56) Morris, C. D.; Chung, I.; Park, S.; Harrison, C. M.; Clark, D. J.; Jang, J. I.; Kanatzidis, M. G., J. Am. Chem. Soc. 2012, 134, 20733-20744. (57) Jang, J. I.; Park, S.; Harrison, C. M.; Clark, D. J.; Morris, C. D.; Chung, I.; Kanatzidis, M. G., Opt. Lett. 2013, 38, 1316-1318. (58) Zhao, H.-J.; Zhang, Y. F.; Chen, L., J. Am. Chem. Soc. 2012, 134, 1993-1995. (59) Geng, L.; Cheng, W. D.; Lin, C. S.; Zhang, W. L.; Zhang, H.; He, Z. Z., Inorg. Chem. 2011, 50, 5679-5686. (60) Liao, J. H.; Marking, G. M.; Hsu, K. F.; Matsushita, Y.; Ewbank, M. D.; Borwick, R.; Cunningham, P.; Rosker, M. J.; Kanatzidis, M. G., J. Am. Chem. Soc. 2003, 125, 9484-9493. (61) Brant, J. A.; Clark, D. J.; Kim, Y. S.; Jang, J. I.; Zhang, J.-H.; Aitken, J. A., Chem. Mater. 2014, 26, 3045-3048. (62) Lekse, J. W.; Moreau, M. A.; McNerny, K. L.; Yeon, J.; Halasyamani, P. S.; Aitken, J. A., Inorg. Chem. 2009, 48, 7516-7518. (63) Jang, J. I.; Clark, D. J.; Brant, J. A.; Aitken, J. A.; Kim, Y. S., Opt. Lett. 2014, 39, 4579-4582. (64) Li, G. M.; Wu, K.; Liu, Q.; Yang, Z. H.; Pan, S. L., J. Am. Chem. Soc. 2016, 138, 7422-7428. (65) Lin, H.; Zhou, L. J.; Chen, L., Chem. Mater. 2012, 24, 3406-3414. (66) Yu, P.; Zhou, L. J.; Chen, L., J. Am. Chem. Soc. 2012, 134, 2227-2235. (67) Liu, B. W.; Zeng, H. Y.; Jiang, X. M.; Wang, G. E.; Li, S. F.; Xu, L.; Guo, G. C., Chem. Sci. 2016, 7, 6273-6277.

Page 34 of 38

(68) Chung, I.; Kanatzidis, M. G., Chem. Mater. 2014, 26, 849-869. (69) Lin, J.; Lee, M. H.; Liu, Z. P.; Chen, C. T.; Pickard, C. J., Phys. Rev. B 1999, 60, 13380-13389. (70) Clark, S. J.; Segall, M. D.; Pickard, C. J.; Hasnip, P. J.; Probert, M. J.; Refson, K.; Payne, M. C., Z. Kristallogr. 2005, 220, 567-570. (71) Baroni, S.; de Gironcoli, S.; Dal Corso, A.; Giannozzi, P., Rev. Mod. Phys. 2001, 73, 515-562. (72) Becker, P., Adv. Mater. 1998, 10, 979-992. (73) Chen, C. T.; Lin, Z. S.; Wang, Z. Z., Appl. Phys. B-Lasers and Opt. 2005, 80, 1-25. (74) Lin, Z. S.; Jiang, X. X.; Kang, L.; Gong, P. F.; Luo, S. Y.; Lee, M. H., J. Phys. D-Appl. Phys. 2014, 47, 19. (75) Chen, C. T.et al. Borate Nonlinear Optical; Wiley-VCH: Berlin, Germany, 2012. (76) Hiltmann, F.; Krebs, B., Z. Anorg. Allg. Chem. 1995, 621, 424-430. (77) Hammerschmidt, A.; Doch, M.; Wulff, M.; Krebs, B., Z. Anorg. Allg. Chem. 2002, 628, 2637-2640. (78) Li, Y. Y.; Li, B. X.; Zhang, G.; Zhou, L. J.; Lin, H.; Shen, J. N.; Zhang, C. Y.; Chen, L.; Wu, L. M., Inorg. Chem. 2015, 54, 4761-4767. (79) Lian, Y. K.; Wu, L. M.; Chen, L., Dalton Trans. 2017, doi: 10.1039/c6dt04767j (80) Zeng, H. Y.; Zheng, F. K.; Guo, G. C.; Huang, J. S., J. Alloys Compd. 2008, 458, 123-129. (81) Poduska, K. M.; DiSalvo, F. J.; Min, K.; Halasyamani, P. S., J. Alloys Compd. 2002, 335, L5-L9. (82) Chen, H. L.; Kuang, H. M.; Chen, W. T., Russ. J. Inorg. Chem. 2012, 57, 1064-1066. (83) Li, C.; Yin, W. L.; Gong, P. F.; Li, X. S.; Zhou, M. L.; Mar, A.; Lin, Z. S.; Yao, J. Y.; Wu, Y. C.; Chen, C. T., J. Am. Chem. Soc. 2016, 138, 6135-6138. (84) Kim, Y.; Martin, S. W.; Ok, K. M.; Halasyamani, P. S., Chem. Mater. 2005, 17, 2046-2051. (85) Song, J.-H.; Freeman, A. J.; Bera, T. K.; Chung, I.; Kanatzidis, M. G., Phys. Rev. B 2009, 79, 245203. (86) Hulme, K. F.; Jones, O.; Davies, P. H.; Hobden, M. V., Appl. Phys. Lett. 1967, 10, 133-135. (87) Zhao, R. Q.; Zhou, J.; Liu, X.; Li, R.; Tang, Q. L., Inorg. Chem. Commun. 2014, 46, 17-20. (88) Hanna, D. C.; Rutt, H. N.; Stanley, C. R.; Smith, R. C.; Lutherda.B, IEEE J. Quantum Electron. 1972, 8, 317-324. (89) Hao, W. Y.; Mei, D. J.; Yin, W. L.; Feng, K.; Yao, J. Y.; Wu, Y. C., J. Solid State Chem. 2013, 198, 81-86. (90) Chung, I.; Song, J.-H.; Jang, J. I.; Freeman, A. J.; Ketterson, J. B.; Kanatzidis, M. G., J. Am. Chem. Soc. 2009, 131, 2647-2656. (91) Luo, Z. Z.; Lin, C. S.; Cui, H. H.; Zhang, W. L.; Zhang, H.; He, Z. Z.; Cheng, W. D., Chem. Mater. 2014, 26, 2743-2749. (92) Lin, Z. H.; Li, C.; Kang, L.; Lin, Z. S.; Yao, J. Y.; Wu, Y. C., Dalton Trans. 2015, 44, 7404-7410. (93) Li, X. S.; Kang, L.; Li, C.; Lin, Z. S.; Yao, J. Y.; Wu, Y. C., J. Mater. Chem. C 2015, 3, 3060-3067. (94) Luo, Z. Z.; Lin, C. S.; Cui, H. H.; Zhang, W. L.; Zhang, H.; Chen, H.; He, Z. Z.; Cheng, W. D., Chem. Mater. 2015, 27, 914-922. (95) Chen, Y. K.; Chen, M. C.; Zhou, L. J.; Chen, L.; Wu, L. M., Inorg. Chem. 2013, 52, 8334-8341. (96) Nguyen, S. L.; Jang, J. I.; Ketterson, J. B.; Kanatzidis, M. G., Inorg. Chem. 2010, 49, 9098-9100. (97) Babo, J.-M.; Wolff, K. K.; Schleid, T., Z. Anorg. Allg. Chem. 2013, 639, 2875-2881. (98) Ni, B. L.; Zhou, H. G.; Jiang, J. Q.; Li, Y.; Zhang, Y. F., Acta Phys. Chim. Sin. 2010, 26, 3052-3060. (99) Ma, Z. J.; Wu, K. C.; Sa, R. J.; Li, Q. H.; Zhang, Y. F., J. Alloys Compd. 2013, 568, 16-20.


34

Page 35 of 38

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(100) Lin, C. S.; Luo, Z. Z.; Cheng, W. D.; Zhang, H.; Zhang, W. L., J. Mater. Chem. 2012, 22, 21713-21719. (101) Duan, R. H.; Yu, J. S.; Lin, H.; Zheng, Y. J.; Zhao, H. J.; Huang-Fu, S. X.; Khan, M. A.; Chen, L.; Wu, L. M., Dalton Trans. 2016, 45, 12288-12291. (102) Ok, K. M.; Halasyamani, P. S.; Casanova, D.; Llunell, M.; Alemany, P.; Alvarez, S., Chem. Mater. 2006, 18, 3176-3183. (103) Halasyamani, P. S.; Poeppelmeier, K. R., Chem. Mater. 1998, 10, 2753-2769. (104) Pell, M. A.; Vajenine, G. V. M.; Ibers, J. A., J. Am. Chem. Soc. 1997, 119, 5186-5192. (105) Banerjee, S.; Malliakas, C. D.; Jang, J. I.; Ketterson, J. B.; Kanatzidis, M. G., J. Am. Chem. Soc. 2008, 130, 12270-12272. (106) Jandali, M. Z.; Eulenberger, G.; Hahn, H., Z. Anorg. Allg. Chem. 1980, 470, 39-44. (107) Boucher, F.; Evain, M.; Brec, R., Acta Crystallogr. Sect. B-Struct. Sci. 1995, 51, 952-961. (108) Durichen, P.; Bensch, W., Acta Crystallogr. Sect. C-Cryst. Struct. Commun. 1998, 54, 706-708. (109) Pearson, R. G., PNAS 1975, 72, 2104-2106. (110) Pearson, R. G., J. Am. Chem. Soc. 1969, 91, 4947-4955. (111) Chen, M. C.; Li, L. H.; Chen, Y. B.; Chen, L., J. Am. Chem. Soc. 2011, 133, 4617-4624. (112) Yu, H. H.; Pan, Z. B.; Zhang, H. J.; Wang, J. Y., J. Materiomics 2016, 2, 55-65. (113) Fang, Q. N.; Lu, D. Z.; Yu, H. H.; Zhang, H. J.; Wang, J. Y., Opt. Lett. 2016, 41, 1002-1005. (114) Chen, M. C.; Li, P.; Zhou, L. J.; Li, L. H.; Chen, L., Inorg. Chem. 2011, 50, 12402-12404. (115) Kleinman, D. A., Phys. Rev. 1962, 126, 1977-1979. (116) Levine, B. F., IEEE J. Quantum Electron. 1973, 9, 946-954. (117) Wynne, J. J., Phys. Rev. Lett. 1971, 27, 17-20. (118) Levine, B. F.; Miller, R. C.; Nordland, W. A., Phys. Rev. B 1975, 12, 4512-4521. (119) Shi, Y.-F.; Chen, Y.-k.; Chen, M.-C.; Wu, L.-M.; Lin, H.; Zhou, L.-J.; Chen, L., Chem. Mater. 2015, 27, 1876-1884. (120) Daszkiewicz, M.; Gulay, L. D.; Lychmanyuk, O. S., Acta Crystallogr. Sect. B-Struct. Sci. 2009, 65, 126-133. (121) Hwu, S. J.; Bucher, C. K.; Carpenter, J. D.; Taylor, S. P., Inorg. Chem. 1995, 34, 1979-1980. (122) Iyer, A. K.; Yin, W. L.; Rudyk, B. W.; Lin, X. S.; Nilges, T.; Mar, A., J. Solid State Chem. 2016, 243, 221-231. (123) Hartenbach, I.; Schleid, T., J. Solid State Chem. 2003, 171, 382-386. (124) Guo, S. P.; Guo, G. C.; Wang, M. S.; Zou, J. P.; Xu, G.; Wang, G. J.; Long, X. F.; Huang, J. S., Inorg. Chem. 2009, 48, 7059-7065. (125) Zhao, H. J., J. Solid State Chem. 2015, 227, 5-9. (126) Zhen, N.; Nian, L. Y.; Li, G. M.; Wu, K.; Pan, S. L., Crystals 2016, 6, 121. (127)Li, S. F.; Zeng, H. Y.; Jiang, X. M.; Liu, B. W.; Guo, G. C., J. Chin. Soc. Rare. Earths. 2016, 34, 685-692. (128) Li, P.; Li, L. H.; Chen, L.; Wu, L. M., J. Solid State Chem. 2010, 183, 444-450. (129) Zhao, H. J.; Zhou, L. J., Eur. J. Inorg. Chem. 2015, 6, 964-968. (130) Zhang, M. J.; Li, B. X.; Liu, B. W.; Fan, Y. H.; Li, X. G.; Zeng, H. Y.; Guo, G. C., Dalton Trans. 2013, 42, 14223-14229. (131) Zhou, L. J.; Chen, L.; Li, J. Q.; Wu, L. M., J. Solid State Chem. 2012, 195, 166-171. (132) Wang, Y.; Zou, X. C.; Feng, X.; Shi, Y. F.; Wu, L. M., J. Solid State Chem. 2017, 245, 110-114. (133) Zhao, H. J., Z. Anorg. Allg. Chem. 2016, 642, 56-59.

(134) Lemley, J. T.; Jenks, J. M.; Hoggins, J. T.; Eliezer, Z.; Steinfink, H., J. Solid State Chem. 1976, 16, 117-128. (135) Rudorff, W.; Schwarz, H. G.; Walter, M., Z. Anorg. Allg. Chem. 1952, 269, 141-152. (136) Sturza, M.; Bugaris, D. E.; Malliakas, C. D.; Han, F.; Chung, D. Y.; Kanatzidis, M. G., Inorg. Chem. 2016, 55, 4884-4890. (137) Luo, Z. Z.; Lin, C. S.; Cheng, W. D.; Zhang, H.; Zhang, W. L.; He, Z. Z., Inorg. Chem. 2013, 52, 273-279. (138) Luo, Z. Z.; Lin, C. S.; Zhang, W. L.; Zhang, H.; He, Z. Z.; Cheng, W. D., Chem. Mater. 2014, 26, 1093-1099. (139) Feng, K.; Jiang, X. X.; Kang, L.; Yin, W. L.; Hao, W. Y.; Lin, Z. S.; Yao, J. Y.; Wu, Y. C.; Chen, C. T., Dalton Trans. 2013, 42, 13635-13641. (140) Richards, W. D.; Wang, Y.; Miara, L. J.; Kim, J. C.; Ceder, G., Energy Environ. Sci. 2016, 9, 3272-3278. (141) Zhu, Z.; Chu, I.-H.; Ong, S. P., Chem. Mater. 2017, doi:10.1021/acs.chemmater.6b04049. (142) Wu, X. W.; Hu, Y.; Pan, H.; Su, Z., Rsc Adv. 2016, 6, 99475-99481. (143) Isaenko, L. I.; Yelisseyev, A. P., Semicond. Sci. Technol. 2016, 31, 123001. (144) Yin, W. L.; Feng, K.; Hao, W. Y.; Yao, J. Y.; Wu, Y. C., Inorg. Chem. 2012, 51, 5839-5843. (145) Susa, K.; Steinfin.H, Inorg. Chem. 1971, 10, 1754-1756. (146) Yohannan, J. P.; Vidyasagar, K., J. Solid State Chem. 2016, 238, 147-155. (147) Wu, K.; Yang, Z. H.; Pan, S. L., Inorg. Chem. 2015, 54, 10108-10110. (148) Wu, K.; Yang, Z. H.; Pan, S. L., Chem. Mater. 2016, 28, 2795-2801. (149) Schwer, H.; Keller, E.; Kramer, V., Z. Kristallogr. 1993, 204, 203-213. (150) Lin, H.; Chen, L.; Zhou, L. J.; Wu, L. M., J. Am. Chem. Soc. 2013, 135, 12914-12921. (151) Lin, H.; Liu, Y.; Zhou, L. J.; Zhao, H. J.; Chen, L., Inorg. Chem. 2016, 55, 4470-4475. (152) Wu, Y. D.; Bensch, W., J. Solid State Chem. 2009, 182, 471-478. (153) Huang, J. B.; Mamat, M.; Pan, S. L.; Yang, Z. H., J. Solid State Chem. 2016, 239, 30-35. (154) Aitken, J. A.; Larson, P.; Mahanti, S. D.; Kanatzidis, M. G., Chem. Mater. 2001, 13, 4714-4721. (155) Schimek, G. L.; Pennington, W. T.; Wood, P. T.; Kolis, J. W., J. Solid State Chem. 1996, 123, 277-284. (156) Schimek, G. L.; Kolis, J. W., Acta Crystallogr. Sect. C-Cryst. Struct. Commun. 1997, 53, 991-992. (157) Auernhammer, M.; Effenberger, H.; Irran, E.; Pertlik, F.; Rosenstingl, J., J. Solid State Chem. 1993, 106, 421-426. (158) Teske, C. L., Z. Naturfor. Sect. B-a J. Chem. Sci. 1979, 34, 544-547. (159) Eisenmann, B.; Hansa, J.; Schafer, H., Rev. Chim., Miner 1984, 21, 817-823. (160) Badikov, V.; Mitin, K.; Noack, F.; Panyutin, V.; Petrov, V.; Seryogin, A.; Shevyrdyaeva, G., Opt. Mater. 2009, 31, 590-597. (161) Chung, I.; Jang, J. I.; Gave, M. A.; Weliky, D. P.; Kanatzidis, M. G., Chem. Commun. 2007, 4998-5000. (162) Fan, Y. H.; Jiang, X. M.; Liu, B. W.; Li, S. F.; Guo, W. H.; Zeng, H. Y.; Guo, G. C.; Huang, J. S., Inorg. Chem. 2017, 56, 962-973. (163) Lin, H.; Chen, L.; Yu, J. S.; Chen, H.; Wu, L. M., Chem. Mater. 2017, 29, 499-503. (164) Bai, L.; Lin, Z. S.; Wang, Z. Z.; Chen, C. T.; Lee, M. H., J. Chem. Phys. 2004, 120, 8772-8778. (165) Liang, F.; Kang, L.; Lin, Z. S.; Wu, Y. C.; Chen, C. T., Coord. Chem. Rev. 2017, 333, 57-70.


35


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

(166) Li, S. F.; Liu, B. W.; Zhang, M. J.; Fan, Y. H.; Zeng, H. Y.; Guo, G. C., Inorg. Chem. 2016, 55, 1480-1485. (167) Zhou, M. L.; Li, C.; Li, X. S.; Yao, J. Y.; Wu, Y. C., Dalton Trans. 2016, 45, 7627-7633. (168)Li, G. M.; Liu, Q.; Wu, K.; Yang, Z. H.; Pan, S. L., Dalton Trans. 2017, 46, 2778-2784. (169)Li, S. F.; Jiang, X. M.; Liu, B. W.; Yan, D.; Lin, C. S.; Zeng, H. Y.; Guo, G. C., Chem. Mater. 2017, 10.1021/acs.chemmater.6b05405 (170) Petrov, V., Opt. Mater. 2012, 34, 536-554. (171) Krymus, A. S.; Myronchuk, G. L.; Parasyuk, O. V.; Lakshminarayana, G.; Fedorchuk, A. O.; El-Naggar, A.; Albassam, A.; Kityk, I. V., Mater. Res. Bull. 2017, 85, 74-79. (172) Ni, Y. B.; Wu, H. X.; Xiao, R. C.; Huang, C. B.; Wang, Z. Y.; Mao, M. S.; Qi, M.; Cheng, G. C., Opt. Mater. 2015, 42, 458-461. (173) Mei, D. J.; Gong, P. F.; Lin, Z. S.; Feng, K.; Yao, J. Y.; Huang, F. Q.; Wu, Y. C., Crystengcomm 2014, 16, 6836-6840. (174) Reshak, A. H.; Azam, S., Opt. Mater. 2014, 37, 97-103. (175)Lin, H.; Zheng, Y. J.; Hu, X. N.; Chen, H.; Yu, J. S.; Wu, L. M., Chemistry, an Asian journal 2017, 12, 453-458. (176) Cheng, X. D.; Wu, H. X.; Tang, X. L.; Wang, Z. Y.; Xiao, R. C.; Huang, C. B.; Ni, Y. B., Acta Phys. Sin. 2014, 63, 184208. (177) Eisenmann, B.; Jakowski, M.; Schafer, H., Rev. Chim., Miner 1983, 20, 329-337. (178) Benghia, A.; Dahame, T.; Bentria, B., Opt. Mater. 2016, 54, 269-275. (179) Badikov, V.; Badikov, D.; Shevyrdyaeva, G.; Tyazhev, A.; Marchev, G.; Panyutin, V.; Petrov, V.; Kwasniewski, A., Phys. Status Solidi-Rapid Research Letters 2011, 5, 31-33. (180) Tyazhev, A.; Kolker, D.; Marchev, G.; Badikov, V.; Badikov, D.; Shevyrdyaeva, G.; Panyutin, V.; Petrov, V., Opt. Lett. 2012, 37, 4146-4148. (181) Kato, K.; Okamoto, T.; Mikami, T.; Petrov, V.; Badikov, V.; Badikov, D.; Panyutin, V, In Nonlinear Frequency Generation and Conversion: Materials, Devices and Applications, 2013; Vol. 8604, pp.860416 (182) Mei, D. J.; Yin, W. L.; Bai, L.; Lin, Z. S.; Yao, J. Y.; Fu, P. Z.; Wu, Y. C., Dalton Trans. 2011, 40, 3610-3615. (183) Yao, J. Y.; Yin, W. L.; Feng, K.; Li, X. M.; Mei, D. J.; Lu, Q. M.; Ni, Y. B.; Zhang, Z. W.; Hu, Z. G.; Wu, Y. C., J. Cryst. Growth 2012, 346, 1-4. (184) Zhang, X.; Yao, J. Y.; Yin, W. L.; Zhu, Y.; Wu, Y. C.; Chen, C. T., Opt. Express 2015, 23, 552-558. (185) Yang, F.; Yao, J. Y.; Xu, H. Y.; Feng, K.; Yin, W. L.; Li, F. Q.; Yang, J.; Du, S. F.; Peng, Q. J.; Zhang, J. Y.; Cui, D. F.; Wu, Y. C.; Chen, C. T.; Xu, Z. Y., Opt. Lett. 2013, 38, 3903-3905. (186) Yang, F.; Yao, J. Y.; Xu, H. Y.; Zhang, F. F.; Zhai, N. X.; Lin, Z. H.; Zong, N.; Peng, Q. J.; Zhang, J. Y.; Cui, D. F.; Wu, Y. C.; Chen, C. T.; Xu, Z. Y., IEEE Photonics Technol. Lett. 2015, 27, 1100-1103. (187) Yuan, J. H.; Li, C.; Yao, B. Q.; Yao, J. Y.; Duan, X. M.; Li, Y. Y.; Shen, Y. J.; Wu, Y. C.; Cui, Z.; Dai, T. Y., Opt. Express 2016, 24, 6083-6087. (188) Kostyukova, N. Y.; Boyko, A. A.; Badikov, V.; Badikov, D.; Shevyrdyaeva, G.; Panyutin, V.; Marchev, G. M.; Kolker, D. B.; Petrov, V., Opt. Lett. 2016, 41, 3667-3670. (189) Xu, W. T.; Wang, Y. Y.; Yan, C.; Xu, D. G.; Yao, J. Y.; Fan, F.; Duan, P.; Yang, Z.; Liu, P. X.; Shi, J.; Liu, H. X.; Yao, J. Q.; 2015 40th International Conference on Infrared, Millimeter and Terahertz Waves, 2015. (190) Li, X. S.; Li, C.; Gong, P. F.; Lin, Z. S.; Yao, J. Y.; Wu, Y. C., J. Mater. Chem. C 2015, 3, 10998-11004.

Page 36 of 38

(191) Badikov, V. V.; Badikov, D. V.; Laptev, V. B.; Mitin, K. V.; Shevyrdyaeva, G. S.; Shchebetova, N. I.; Petrov, V., Opt. Mater. Express 2016, 6, 2933. (192) Liu, B. W.; Zeng, H. Y.; Zhang, M. J.; Fan, Y. H.; Guo, G. C.; Huang, J. S.; Dong, Z. C., Inorg. Chem. 2015, 54, 976-981. (193) Kuo, S. M.; Chang, Y. M.; Chung, I.; Jang, J. I.; Her, B. H.; Yang, S. H.; Ketterson, J. B.; Kanatzidis, M. G.; Hsu, K. F., Chem. Mater. 2013, 25, 2427-2433. (194) Rad, H. D.; Hoppe, R., Z. Anorg. Allg. Chem. 1981, 483, 18-25. (195) Wu, K.; Su, X.; Pan, S. L.; Yang, Z. H., Inorg. Chem. 2015, 54, 2772-2779. (196) Wu, K.; Yang, Z. H.; Pan, S. L., Angew. Chem. Inter. Edit. 2016, 55, 6712-6714. (197) Tan, D. M.; Lin, C. S.; Luo, Z. Z.; Zhang, H.; Zhang, W. L.; He, Z. Z.; Cheng, W. D., Dalton Trans. 2015, 44, 7673-7678. (198) Zhen, N.; Wu, K.; Wang, Y.; Li, Q.; Gao, W. H.; Hou, D. W.; Yang, Z. H.; Jiang, H. D.; Dong, Y. J.; Pan, S. L., Dalton Trans. 2016, 45, 10681-10688. (199) Wu, K.; Su, X.; Yang, Z.; Pan, S., Dalton Trans. 2015, 44, 19856-19864. (200) Yin, W. L.; Iyer, A. K.; Li, C.; Lin, X. S.; Yao, J. Y.; Mar, A., J. Solid State Chem. 2016, 241, 131-136. (201) Guo, Y. F.; Zhou, Y. Q.; Lin, X. S.; Chen, W. D.; Ye, N., Opt. Mater. 2014, 36, 2007-2011. (202) Boursier, E.; Segonds, P.; Menaert, B.; Badikov, V.; Panyutin, V.; Badikov, D.; Petrov, V.; Boulanger, B., Opt. Lett. 2016, 41, 2731-2734. (203) Boursier, E.; Segonds, P.; Debray, J.; Inacio, P. L.; Panyutin, V.; Badikov, V.; Badikov, D.; Petrov, V.; Boulanger, B., Opt. Lett. 2015, 40, 4591-4594. (204) Lai, W. H.; Haynes, A. S.; Frazer, L.; Chang, Y. M.; Liu, T. K.; Lin, J. F.; Liang, I. C.; Sheu, H. S.; Ketterson, J. B.; Kanatzidis, M. G.; Hsu, K. F., Chem. Mater. 2015, 27, 1316-1326. (205)Haynes, A. S.; Liu, T.-K.; Frazer, L.; Lin, J.-F.; Wang, S.-Y.; Ketterson, J. B.; Kanatzidis, M. G.; Hsu, K.-F., J. Solid State Chem. 2017, 248, 119-125. (206) Yin, W. L.; Lin, Z. H.; Kang, L.; Kang, B.; Deng, J. G.; Lin, Z. S.; Yao, J. Y.; Wu, Y. C., Dalton Trans. 2015, 44, 2259-2266. (207)Yin, W. L.; Iyer, A. K.; Li, C.; Yao, J. Y.; Mar, A., J. Mater. Chem. C 2017, 5, 1057-1063. (208) E. Parthé, Crystal Chemistry of Tetrahedral Structures, Gordon and Breach Science Publishers Inc, New York, 1964. (209) Zhang K.C., Wang X.M., Nonlinear Optics: Crystal Materials Science, Science Press, 2006. (210) Mendil, R.; Ben Ayadi, Z.; Djessas, K., J. Alloys Compd. 2016, 678, 87-92. (211) Tsuji, I.; Shimodaira, Y.; Kato, H.; Kobayashi, H.; Kudo, A., Chem. Mater. 2010, 22, 1402-1409. (212) Devlin, K. P.; Glaid, A. J.; Brant, J. A.; Zhang, J.-H.; Srnec, M. N.; Clark, D. J.; Kim, Y. S.; Jang, J. I.; Daley, K. R.; Moreau, M. A.; Madura, J. D.; Aitken, J. A., J. Solid State Chem. 2015, 231, 256-266. (213) Rosmus, K. A.; Brant, J. A.; Wisneski, S. D.; Clark, D. J.; Kim, Y. S.; Jang, J. I.; Brunetta, C. D.; Zhang, J.-H.; Srnec, M. N.; Aitken, J. A., Inorg. Chem. 2014, 53, 7809-7811. (214) Brant, J. A.; Clark, D. J.; Kim, Y. S.; Jang, J. I.; Weiland, A.; Aitken, J. A., Inorg. Chem. 2015, 54, 2809-2819. (215) Petrov, V.; Yelisseyev, A.; Isaenko, L.; Lobanov, S.; Titov, A.; Zondy, J. J., Appl. Phys. B-Lasers and Opt. 2004, 78, 543-546.


36

Page 37 of 38

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(216) Bai, L.; Lin, Z. S.; Wang, Z. Z.; Chen, C. T., J. Appl. Phys. 2008, 103, 083111. (217) Isaenko, L.; Krinitsin, P.; Vedenyapin, V.; Yelisseyev, A.; Merkulov, A.; Zondy, J. J.; Petrov, V., Cryst. Growth Des. 2005, 5, 1325-1329. (218) Reshak, A. H.; Kamarudin, H.; Auluck, S., J. Mater. Sci. 2013, 48, 1955-1965. (219) Reshak, A. H., J. Appl. Phys. 2016, 119, 095709. (220) Zhang, J.-H.; Clark, D. J.; Brant, J. A.; Sinagra, C. W., III; Kim, Y. S.; Jang, J. I.; Aitken, J. A., Dalton Trans. 2015, 44, 11212-11222. (221)Wu, K.; Yang, Z. H.; Pan, S. L., Chem Commun, 2017, DOI:10.1039/C6CC09565H (222) B. Pamplin, Prog. Cryst. Growth Charact. 1981, 3, 179–192. (223) Badikov, V. V.; Don, A. K.; Mitin, K. V.; Seregin, A. M.; Sinaiskii, V. V.; Schebetova, N. I., Quantum Electron. 2003, 33, 831-832. (224) Umemura, N.; Mikami, T.; Kato, K., Opt. Commun. 2012, 285, 1394-1396. (225) Zhang, M. J.; Jiang, X. M.; Zhou, L. J.; Guo, G. C., J. Mater. Chem. C 2013, 1, 4754-4760. (226) Collin, G.; Flahaut, J.; Guittard, M.; Loireaulozach, A. M., Mater. Res. Bull. 1976, 11, 285-292. (227) Andreev, Y. M.; Geiko, P. P.; Badikov, V. V.; Panyutin, V. L.; Shevyrdyaeva, G. S.; Ivaschenko, M. V.; Karapuzikov, A. I.; Sherstov, I. V., 9th Joint International Symposium on Atmospheric and Ocean Optics/Atmospheric Physics, Tomsk, Russia, 2002; pp 120-127. (228) Jantz, W.; Koidl, P.; Wettling, W., Appl. Phys. A-Mater. Sci. & Proc. 1983, 30, 109-115. (229) Zhou, M. L.; Kang, L.; Yao, J. Y.; Lin, Z. S.; Wu, Y. C.; Chen, C. T., Inorg. Chem. 2016, 55, 3724-3726.

(230) Jorgens, S.; Johrendt, D.; Mewis, A., Z. Anorg. Allg. Chem. 2002, 628, 1765-1769. (231) Toffoli, P.; Rouland, J. C.; Khodadad, P.; Rodier, N., Acta Crystallogr. Sect. C-Cryst. Struct. Commun. 1985, 41, 645-647. (232) Menzel, F.; Brockner, W.; Carrillocabrera, W., Heteroat. Chem. 1993, 4, 393-398. (233) Gorgut, G. P.; Fedorchuk, A. O.; Kityk, I. V.; Sachanyuk, V. P.; Olekseyuk, I. D.; Parasyuk, O. V., J. Cryst. Growth 2011, 324, 212-216. (234) Zhang, G.; Liu, T.; Zhu, T. X.; Qin, J. G.; Wu, Y. C.; Chen, C. T., Opt. Mater. 2008, 31, 110-113. (235) Li, Y. Y.; Liu, P. F.; Hu, L.; Chen, L.; Lin, H.; Zhou, L. J.; Wu, L. M., Adv. Opt. Mater. 2015, 3, 957-966. (236)Liu, P. F.; Li, Y. Y.; Zheng, Y. J.; Yu, J. S.; Duan, R. H.; Chen, H.; Lin, H.; Chen, L.; Wu, L. M., Dalton Trans. 2017, 46, 2715-2721. (237) Li, Y. Y.; Liu, P. F.; Lin, H.; Wang, M. T.; Chen, L., Inorg. Chem. Front. 2016, 3, 952-958. (238) Zhang, Q.; Chung, I.; Jang, J. I.; Ketterson, J. B.; Kanatzidis, M. G., J. Am. Chem. Soc. 2009, 131, 9896-9897. (239) Gitzendanner, R. L.; DiSalvo, F. J., Inorg. Chem. 1996, 35, 2623-2626. (240) Beck, J.; Hedderich, S.; Kollisch, K., Inorg. Chem. 2000, 39, 5847-5850. (241) Krebs, B., Angew. Chem. Int. Edit. 1983, 22, 113-134.


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For Table of Contents Use Only

Mid-infrared nonlinear optical materials based chalcogenides: structure-property relationship

on

metal

Fei Liang, †,‡ Lei Kang, †,‡ Zheshuai Lin, *,†,‡ Yicheng Wu † † Center for Crystal R&D, Key Lab Functional Crystals and Laser Technology of Chinese Academy of Sciences, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, PR China. ‡ University of Chinese Academy of Sciences, Beijing 100190, PR China

According to different structure motifs, the prospects of metal chalcogenides for mid-IR nonlinear optical applications are systematically investigated and summarized based on the structure-property relationship.


38

Mid-Infrared Nonlinear Optical Materials Based on Metal

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