Synthesis, Structure, and Characterization of Two Mixed-Cation

Article Cite This: Inorg. Chem. 2019, 58, 7118−7125

pubs.acs.org/IC

Synthesis, Structure, and Characterization of Two Mixed-Cation Quaternary Chalcogenides K2BaSnQ4 (Q = S, Se) Xiaoyu Luo,†,‡,§ Zhuang Li,†,‡,§ Fei Liang,†,§ Yangwu Guo,†,‡,§ Yicheng Wu,†,∥ Zheshuai Lin,† and Jiyong Yao*,†,‡

Downloaded via UNIV OF SOUTHERN INDIANA on July 24, 2019 at 04:29:52 (UTC). See https://pubs.acs.org/sharingguidelines for options on how to legitimately share published articles.

†

Beijing Center for Crystal Research and Development, Key Lab of Functional Crystals and Laser Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China ‡ Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, P. R. China § University of Chinese Academy of Sciences, Beijing 100049, P. R. China ∥ Institute of Functional Crystal Materials, Tianjin University of Technology, Tianjin 300384, P. R. China S Supporting Information *

ABSTRACT: Two new isostructural metal chalcogenides, K2BaSnS4 and K2BaSnSe4, have been isolated for the first time. They feature the intriguing ∞ 1[BaSnQ4]2− (Q = S, Se) tunnel structures which are separated by K+ cations. Experiments combined with theoretical calculations demonstrate that K2BaSnS4 possesses a large energy gap (3.09 eV), which is conducive for large laser-induced damage thresholds (LDTs), and maintains a relatively moderate SHG response (0.5 × AgGaS2) in the meanwhile. Moreover, K2BaSnS4 possesses good phasematchability, which stems from its suitable birefringence (0.04@ 2.09 μm).

■

(e.g., Li+, Na+, K+, Ca2+) are normally located in the voids to draw the NLO-active units closer, which is beneficial to increase NLO responses. Combining different NLO building groups into one compound may produce a compound with a strong SHG response. As a result of continuous exploratory efforts, many NLO compounds have been reported, for instance, BaGa4Q7 (Q = S, Se),19,22 Zn3P2S8,24 Na2Ge2Se5,25 Ba5CdGa6Se15,20 Sr5ZnGa6S15,26 Na2ZnGe2S6,27 KHg4Ga5Se12,10 AgGa2PS6,9 Ba4CuGa5Q12 (Q = S, Se),15 BaHgSe2,13 ACd4Ga5S12 (A = K, Rb, Cs),16 Na2Ga2MS6 (M = Ge, Sn),28 etc. The incorporation of a strongly electronic positive alkali/ alkaline-earth metal can significantly increase the band gap by reducing the band dispersion. Besides, if both alkali and alkaline-earth cations are incorporated, the different charge/ size combinations of different cations may have cooperative effects on the arrangement of anions, which may increase the chances of isolating new phases with desirable packing of the NLO-active groups. In this work, through the combination of the relative large alkali metal K+ and alkaline-earth cation Ba2+, with the tetrahedral NLO-active [SnQ4] units, two new mixed cation chalcogenides (i.e., K2BaSnS4 andK2BaSnSe4) have been successfully synthesized. Experiments and calculations indicate

INTRODUCTION Infrared (IR) nonlinear optical (NLO) materials are key materials in generating new coherent light sources (3−20 μm).1 Suitable IR NLO materials are essential to produce highquality, simple, and high-efficiency all-solid-state IR laser equipment. Currently, the commercial chalcopyrite-type IR NLO crystals AgGaQ2 (Q = S, Se) and ZnGeP2 show many intrinsic drawbacks limiting their applications.2−4 Therefore, it is important to discover new IR NLO materials with better comprehensive properties. Generally speaking, promising NLO materials should meet various demands, including having (I) a wide IR−transparent range, especially covering beyond the 8−14 μm atmospheric window, (II) a large SHG response, (III) high LDTs, and (IV) the ability to achieve phase-match, which actually requires a moderate optical birefringence.5 Metal chalcogenides with wide band gaps are promising due to their multiple atomic connections and wide transparency.1,6,7 Structurally, aligned arrangements of the NLO building groups are the origin of a large macroscopic NLO response. These NLO building groups usually include the MX4 tetrahedra (M = Ga, In, Si, Ge, etc.; X = S, Se, Te), d10 (e.g., Ag+, Zn2+, Cd2+, Hg2+) metal cation centered tetrahedra, d0 (e.g., Ta5+, Zr4+) cation centered units, some polar structural units centered by cations with ns2 lone pairs of electrons (e.g., Bi3+, Sb3+, Pb2+), and π-conjugated units such as HgSe3 and AgSe3.8−23 Simultaneously, cations © 2019 American Chemical Society

Received: April 2, 2019 Published: May 8, 2019 7118

DOI: 10.1021/acs.inorgchem.9b00967 Inorg. Chem. 2019, 58, 7118−7125

Article

Inorganic Chemistry that K2BaSnS4 possesses both a large band gap and moderate SHG response (3.09 eV, 0.5 × AGS). Moreover, the phasematchable property makes its application feasible. The synthesis, structure, and characterization of these two compounds are reported in this work.

■

Table 2. Selected Interatomic Distances for K2BaSnS4 and K2BaSnSe4 K2BaSnS4 Sn1−S4 Sn1−S1 Sn−S2 Sn1−S3 Ba1−S4 Ba1−S2 Ba1−S3 Ba1−S1 Ba1−S1 Ba1−S3 Ba1−S3

EXPERIMENTAL SECTION

Synthesis of the Crystal. Single crystals of K2BaSnS4 and K2BaSnSe4 were achieved directly via a spontaneous crystallization method. First, 0.132 g (0.188 g) of K2S (K2Se), 0.169 g (0.216 g) of BaS (BaSe), and 0.182 g (0.276 g) of SnS2 (SnSe2) were mixed according to the molar ratio of 1.2:1:1 (with a little K2S (K2Se) serving as flux) and then ground and transferred into fused-silica tubes in a glovebox. The tube was placed in a heating furnace after it was sealed under high vacuum. The heating temperature was raised to 1173 K in 20 h with a duration of 24 h, and then the furnace was slowly cooled to 473 K at 4 K/h to room temperature. The yields were 20% and 14.7% for synthesized K2BaSnS4 and K2BaSnSe4, respectively. The resultant block-shaped crystals with good morphology were carefully picked for the following measurements. Structure Determination. Single-crystal XRD data was obtained at 153 K on a Rigaku AFC10 diffractometer with Mo−Kα (λ = 0.71073 Å) radiation. The crystal data of two title compounds were analyzed with Crystal Clear software. The XPREPF program was used to simulate the face-indexed absorption corrections. The SHELXTLS program was utilized to determine the crystal structure. The leastsquares program SHELXL of the SHELXTL.PC suite of programs was used for the refinement.29 The crystallographic data of K2BaSnS4 and K2BaSnSe4 are given in Tables 1−4.

K2BaSnS4

K2BaSnSe4

Fw a (Å) b (Å) c (Å) α (deg) β (deg) γ (deg) space group V (Å3) Z T (K) λ (Å) ρc (g/cm3) μ (mm−1) R (F)a Rw (F02)b

462.47 25.419(4) 25.419(4) 7.4974(15) 90 90 120 R3c 4195.4(12) 18 153.15 0.71073 3.295 8.576 0.0336 0.0840

650.07 26.444(4) 26.444(4) 7.7452(15) 90 90 120 R3c 4690.6(13) 18 153.15 0.71073 4.142 20.837 0.0353 0.0849

× × × ×

2 2 2 2

×2

Sn1−Se4 Sn1−Se1 Sn1−Se3 Sn1−Se2 Ba1−Se3 Ba1−Se4 Ba1−Se1 Ba1−Se3 Ba1−Se2 Ba1−Se1 Ba1−Se3

2.4935(18) 2.5136(16) 2.5275(16) 2.5283(16) 3.3462(16) 3.3499(18) 3.3868(16) 3.3901(16) 3.3955(16) 3.4041(16) 3.4302(17)

×2 ×2 ×2 ×2 ×2

Table 3. Fractional Atomic Coordinates (× 104) and Equivalent Isotropic Displacement Parameters (Å2 × 103) for K2BaSnS4

Table 1. Crystal Data and Structure Refinement for K2BaSnS4 and K2BaSnSe4 chemical content

K2BaSnSe4 2.368(3) 2.386(2) 2.392(2) 2.398(2) 3.224(3) 3.236(2) 3.255(2) 3.265(2) 3.275(2) 3.283(2) 3.315(2)

atom

Wyckoff

x

y

z

U (eq)

Sn1 Ba1 K1 S1 S2 S3 K2 S4 K3

18b 18b 6a 18b 18b 18b 18b 18b 18b

5172.2(3) 4807.0(2) 4653.5(8) 5668.2(10) 5767.6(9) 4254.4(9) 3333 4980.6(18) 6332(3)

8523.7(2) 6750.4(2) 9977.0(8) 8104.1(10) 9136.7(9) 7651.2(10) 6667 9085.7(14) 10207(2)

359.7(8) 356.4(7) 770(2) 2057(3) 2086(3) −641(3) −3032(6) 2523(3) 723(9)

12.73(15) 15.45(14) 13.2(3) 14.9(4) 15.6(4) 15.9(4) 38.4(9) 40.0(8) 70.6(19)

were slightly more resistant to moisture than the polycrystalline powder, they were also hydroscopic and very small, only dozens of micrometers in size. Thus, single crystals of K2BaSnSe4 were used only to collect the single crystal XRD data. Diffuse Reflectance Spectra. The diffuse reflectance spectrum of K2BaSnS4 (200−2000 nm) was recorded using a Cary 5000 UV−vis− NIR spectrophotometer, in which BaSO4 was used as a reference. Raman Spectroscopy. The unpolarized Raman spectrum of K2BaSnS4 powder sample was recorded using a LABRAM HR Evolution spectrometer equipped with a CCD detector and 532 nm solid state lasers, in which the scanning range was set to 100−600 cm−1 and the spectral resolution was 2 cm−1. SHG Measurement. The SHG response of K2BaSnS4 was measured according to the Kurtz−Perry method.30 The wavelength of pumping light was 2.09 μm. The sizes of K2BaSnS4 powder sample used for measurements were 20−41, 41−74, 74−105, 105−150, and 150−200 μm, with AgGaS2 in similar size ranges used as the reference. Differential Scanning Calorimetry (DSC). The DSC curve of K2BaSnS4 was recorded by a LabsysTG-DTA16 (SETARAM) thermal analyzer. In the test, about 15 mg of K2BaSnS4 crystals was placed in an evacuated silica tube with a size of 5 mm o.d. × 3 mm i.d., and the heating temperature was raised to 1043 °C with a heating rate of 15 °C/min, and then the temperature was slowly cooled to room temperature with a cooling rate of 15 °C/min. Al2O3 was used as the reference. Electronic Structure Calculations. The first-principles calculations for K2BaSnS4 and K2BaSnSe4 was implemented by the planewave pseudo-potential method.31,32 The electronic structures were determined using the CASTEP package.33 The ion−electron interactions of elements in the compound were simulated by using the optimized ultrasoft pseudo-potentials. The best norm-conserving pseudo-potentials of all elements are in the form of Kleinman− Bylander for simulating the relationship between atomic cores and outer-shell electrons, and K 3p64s1, Ba 5p66s2, Sn 5s25p2, S 3s23p4, and Se 4s24p4 electrons were determined to be the valence electrons. We

R(F) = Σ||Fo| − |Fc||/Σ|Fo|, for F02 > 2σ(F02). bRw(F02) = {Σ[w(|Fo|2 − |Fc|2)2]/Σ[w(|Fo|4)]}1/2 for all data, and w−1 = σ2(F02) + (zP)2, where P = (max(F02) + 2Fc2)/3. a

Synthesis of Polycrystalline Powder. K2BaSnQ4 powder was synthesized by the stoichiometric high-temperature solid state reaction of K2Q, BaQ, and SnQ2. The tubes loaded with the above mixture were sealed and heated to 773 K in 12 h with a duration of 48 h, and then the furnace was shut off. The PXRD pattern of the K2BaSnS4 powder sample was measured at 20 °C on a Bruker D8 Focus diffractometer (λ = 1.5418 Å, scanning step width of 0.05°, counting time of 0.1 s/step, scanning 2θ = 10−70°). The experimental XRD powder pattern was in accordance with the simulation (Figure 1). Unfortunately, the polycrystalline selenide K2BaSnSe4 was strongly hygroscopic, which precludes its further characterization. Although the single crystals of K2BaSnSe4 7119

DOI: 10.1021/acs.inorgchem.9b00967 Inorg. Chem. 2019, 58, 7118−7125

Article

Inorganic Chemistry

Table 4. Fractional Atomic Coordinates (× 104) and Equivalent Isotropic Displacement Parameters (Å2 × 103) for K2BaSnSe4 atom

Wyckoff

x

y

z

U (eq)

K1 K2 K3 Sn1 Ba1 Se1 Se2 Se3 Se4

18b 6a 18b 18b 18b 18b 18b 18b 18b

4628.2(15) 3333 6268(3) 5176.4(4) 4795.2(3) 5672.2(6) 5786.4(6) 4241.7(6) 4988.0(11)

9967.1(13) 6667 10227(3) 8515.0(4) 6746.9(3) 8083.7(6) 9150.2(6) 7637.3(6) 9092.2(8)

828(4) −3019(11) 746(8) 354.5(12) 359.2(10) 2088.3(16) −2121.8(17) −668.8(17) 2545(2)

18.8(7) 57(2) 43.3(17) 11.6(2) 13.9(2) 13.6(3) 13.2(3) 15.2(3) 42.2(6)

following structural discussion. The unit cell parameters of K2BaSnS4 are a = b = 25.419(4) Å, c = 7.4974(15) Å, and Z = 18. There are three crystallographically independent K atoms, one independent Ba atom, one independent Sn atom, and four independent S atoms. The valences of K, Ba, Sn, and S respectively are 1+, 2+, 4+, and 2−, owing to the absence of a S−S bond and metal−metal interactions. The Sn−S bond lengths and S−Sn−S angles vary from 2.368(3) to 2.398(2) Å and from 102.62(9)° to 113.36(8)°, respectively. These bond lengths and angles are in accordance with those of Na2BaSnS4 and Li2BaSnS4.34,35 The interstitial K+ cations are coordinated with six S atoms by weak electrostatic interactions (Figure 2e), while the Ba2+ cations are surrounded by seven S atoms to form [BaS7] polyhedra (Figure 2d). This kind of coordination environment can also be found in Na2BaSnSe4, Na2BaGeS4, and Na2BaGeSe4.34 The crystal structure of K2BaSnS4 can be described as follows. Sn atoms are tetrahedrally connected to four S atoms to form isolated [SnS4] tetrahedra. These tetrahedra are further connected with the distorted [BaS7] polyhedra by sharing edges or corners to construct ∞ 1[BaSnS4]2− tunnel structures which are separated by K+ cations (Figure 2a and c). From another point of view, 24membered rings are built by edge-sharing [KS6] polyhedra with [BaS7] and [SnS4] locating in the voids (Figure 2b). K2BaSnS4 and K2BaSnSe4 belong to the A2BaMIVQ4 (A = Li, Na, K, Cu, and Ag; MIV = Si, Ge, and Sn; Q = S and Se) family. Interestingly, compounds in this family exhibit rich structural transformation, which is strongly influenced by the A cations (Table S1).36 On one hand, Ag, Cu, and Li cations show a four-coordinated environment in this family, and the Ag, Cu,

Figure 1. Experimental and calculated powder X-ray diffraction patterns of K2BaSnS4; peaks marked with * were due to a tiny amount of KSnS4 impurity in P21/n. chose values of 800 eV and 4 × 4 × 2 for the high kinetic energy cutoff and the Monkhorst−Pack k-point meshes, respectively. Tests indicated that these calculation parameter settings are accurate enough for the current target.

■

RESULTS AND DISCUSSION Crystal Structure. K2BaSnS4 and K2BaSnSe4 are isostructural compounds, crystallizing in the hexagonal space group R3c. Here, K2BaSnS4 is taken as the representative for the

Figure 2. (a) Crystal structure of K2BaSnS4. (b) KS6 octahedra are linked with each other to form 24-membered rings. (c) The ∞ 1[BaSnS4]2− tunnel structure. (d) Coordination environment of Ba2+ cation. (e) Coordination environment of K+ cation. 7120

DOI: 10.1021/acs.inorgchem.9b00967 Inorg. Chem. 2019, 58, 7118−7125

Article

Inorganic Chemistry

Figure 3. Optical reflection spectrum of K2BaSnS4: the (F(R)hν)2 versus hν plot (a) and the (F(R)hν)1/2 versus hν plot (b).

the three-dimensional tunnel structure is formed by edgesharing [BaS8] polyhedra and isolated [SnS4] tetrahedra, in which Na cations are located in the tunnels. Optical Properties. The band gap of K2BaSnS4 can be deduced from the Kubelka−Munk equation.37,38 The (F(R) hν)2 and (F(R)hν)1/2 versus hν results, shown in Figure 3a and b, are plotted to determine whether K2BaSnS4 is the direct or indirect band gap. From Figure 3, the band gap obtained from the (F(R)hν)1/2 versus hν plot agrees with the “light-yellow” color of K2BaSnS4. Consequently, the K2BaSnS4 possessed an indirect band gap of 3.09 eV. Generally speaking, strong photon absorption will increase thermal effects, resulting in laser damage for NLO materials. However, an increasing band gap can solve the problems of photon absorption, thereby the

and Li analogues show similar tunnel structures constructed by the interconnection of corner-sharing [BaQ8] units with A cations and MIVQ4 groups filling in respective tunnels (Figure S1, Ag2BaSnS4 is chosen as the representative). On the other hand, Na and K cations are connected with six Q atoms in this family. Except for Na2BaSnS4, all of the Na and K analogues crystallized in the same space group R3c and adopt the same crystal structure described above. Compared with Na2BaSnS4, the K+ cations are coordinated with six S atoms to form [KS6] octahedra in K2BaSnS4, which is the same as the [NaS6] units in Na2BaSnS4, and the Sn atoms adopt the [SnS4] tetrahedra in both K2BaSnS4 and Na2BaSnS4; however, the Ba2+ cations are surrounded by seven S atoms to form [BaS7] polyhedra in K2BaSnS4 and [BaS8]polyhedra in Na2BaSnS4. In Na2BaSnS4, 7121

DOI: 10.1021/acs.inorgchem.9b00967 Inorg. Chem. 2019, 58, 7118−7125

Article

Inorganic Chemistry

S2),34and Li2BaGeS4 (0.5 × AgGaS2)35 but is smaller than Li2BaSnS4 (0.7 × AgGaS2),35 Li2BaGeSe4 (1.1 × AgGaS2),35 and Li2BaSnSe4 (1.3 × AgGaS2).35 But, Li2BaMIVQ4 (MIV = Ge, Sn; Q = S, Se) seems to exhibit a slightly better NLO performance than K2BaSnQ4 (Li2BaSnS4 (0.7 × AgGaS2, 3.66 eV)35 and Li2BaSnS4 (0.7 × AgGaS2, 3.07 eV)35), for the following reasons. Li−Q bonds display much more covalent characteristics than K−Q bonds. LiQ4 units can show a large distortion in the anionic framework and thus make some contributions to NLO response. In comparison, K ions are relatively isolated and have little covalency in bonding. Generally, they do not directly influence the overall NLO response based on the anionic group theory. Furthermore, Li ions are much smaller than K ions. Thus, NLO active units in Li2BaMIVQ4 exhibit a more condensed stacking manner, which leads to a relatively larger SHG response. For comparisons, the properties of several NLO materials with a wide band gap (Eg > 3.0 eV) and phase-matching behavior are listed in Table 5. It is remarkable that K2BaSnS4 possesses balanced overall properties of wide band gap and moderate SHG response.

LDT of NLO materials will be significantly improved. Thus, the larger band gap of K2BaSnS4 (3.09 eV), compared with the benchmark AgGaS2, ZnGeP2, and AgGaSe2 (1.80, 2.65, and 1.75 eV, respectively), is advantageous for the improvement of LDT and for realizing high-power laser output. The Raman spectrum of K2BaSnS4 is shown in Figure 4. The most remarkable Raman shifts situate at 346 and 363 cm−1,

Table 5. Properties Comparison of Some Promising IR NLO Chalcogenides with a Large Band Gap (Eg > 3.1 eV)a and Phase-Matching Behavior Figure 4. Raman spectrum of K2BaSnS4.

which arise from Sn−S vibrations for K2BaSnS4. The similar peaks can also be observed in Li2HgSnS4 (346 cm−1) and Na2BaSnS4 (334 cm−1, 368 cm−1).34,39 Furthermore, the Raman shift below 210 cm−1 (including 120, 150, 172, and 210 cm−1) are mainly attributed to K−S and Ba−S vibrations for K2BaSnS4. As shown in Figure 5a, the SHG intensity goes up gradually with the increase of particle size and finally becomes saturated. This kind of curve indicates type-I phase-matching, which is of great value for IR NLO crystals to be practical. Moreover, K2BaSnS4 demonstrates a relatively moderate SHG response at the plateau (200−250 μm), which is about 0.5 × AgGaS2 (Figure 5b). The SHG response is also comparable to Na2BaSnS4 (0.5 × AgGaS2),34 Na2BaGeS4 (0.3 × AgGa-

a

compound

Eg (eV)

dij (× AGS)

LiGaS243 Na2BaGeS434 Li2BaGeS435 LiInS244 BaGa4S722 Li2In2GeS645 LiGaSe243 Na2BaSnS434 Na2ZnGe2S627 BaGa2GeS617 Na2CdGe2S646 K2BaSnS4 Li2CdGeS447 Zn3(PS4)224

4.15 3.70 3.66 3.57 3.54 3.45 3.34 3.27 3.25 3.23 3.21 3.09 3.15 3.12

0.4 0.3 0.5 0.5 0.5 1.0 0.7 0.5 0.9 1.0 0.8 0.5 2.0 2.6

AgGaS2 (AGS) is taken as the reference.

Figure 5. (a) Phase-matching curves of K2BaSnS4. (b) Oscilloscope traces of SHG signals for K2BaSnS4. 7122

DOI: 10.1021/acs.inorgchem.9b00967 Inorg. Chem. 2019, 58, 7118−7125

Article

Inorganic Chemistry Thermal Properties. The DSC curve of K2BaSnS4 is exhibited in Figure 6. It can be seen that K2BaSnS4 has three

while the contributions from alkali metal K and alkaline-earth metal Ba are negligible (the SHG properties of K2BaSnSe4 are dominantly determined by the [SnSe4] tetrahedra).40,41 K2BaSnS4 and K2BaSnSe4 belong to class 3m. Because of the restriction of Kleinman’s symmetry,42 there are only three independent SHG tensors (d11 = 3.03, d24 = 1.81, and d33 = −0.47 pm/V for K2BaSnS4; d11 = 7.52, d24 = 4.07, and d33 = −1.39 pm/V for K2BaSnSe4). The calculated SHG coefficients of K2BaSnS4 (dij = 3.03 pm/V) are comparable to that of Na2BaSnS4 (dij = 4.63 pm/V) and are roughly consistent with the experimental SHG response value (0.5 × AgGaS2). In addition, the calculated refractive dispersion curves of K2BaSnS4 are shown in Figure 8. K2BaSnS4 possesses two

Figure 6. DSC pattern for K2BaSnS4.

endothermic peaks at 530, 634, and 690 °C and two exothermic peaks at 765 and 694 °C, which means K2BaSnS4 is an incongruent melting compound. Theoretical Studies. As illustrated in Figure 7a and c, K2BaSnS4 and K2BaSnSe4 are indirect transition semiconductors with the VBM and CBM located at the Q and Γ points, respectively. The calculated Eg values are 2.30 eV for K2BaSnS4 and 1.85 eV for K2BaSnSe4. As a result of the discontinuity of the LDA exchange-correlation functions, the calculated band gap values are often lower than the measured ones. From the density of states (DOS) diagrams of K2BaSnS4 and K2BaSnSe4 (Figure 7b and d), the top of valence bond (VB) and the bottom of the conduction bond (CB) mainly stem from the S-3p (Se-4p) state with the mix of a significant part of Sn, K, and Ba orbitals. The SHG properties of K2BaSnS4 are dominantly determined by the [SnS4] tetrahedra,

Figure 8. Calculated refractive dispersion curve of K2BaSnS4.

independent refractive indexes (nx = ny, and nz). In general, a moderate birefringence (0.04−0.10) is of vital importance for IR NLO crystals to be phase-matchable. After calculation, the birefringence (Δn) at 2.09 μm is 0.04 for K2BaSnS4. The moderate birefringence makes the K2BaSnS4 easy to achieve

Figure 7. Calculated electronic band structure of K2BaSnS4 (a) and K2BaSnSe4 (c) by the PBE functional. Total DOS of K2BaSnS4 (b) and K2BaSnSe4 (d). 7123

DOI: 10.1021/acs.inorgchem.9b00967 Inorg. Chem. 2019, 58, 7118−7125

Article

Inorganic Chemistry

J. Appl. Physics, Part 1 Regul. Pap. Short Notes Rev. Pap. 1997, 36, 700−703. (5) Kang, L.; Zhou, M.; Yao, J.; Lin, Z.; Wu, Y.; Chen, C. Metal Thiophosphates with Good Mid-Infrared Nonlinear Optical Performances: A First-Principles Prediction and Analysis. J. Am. Chem. Soc. 2015, 137, 13049−13059. (6) Guo, S. P.; Chi, Y.; Guo, G. C. Recent Achievements on Middle and Far-Infrared Second-Order Nonlinear Optical Materials. Coord. Chem. Rev. 2017, 335, 44−57. (7) Liang, F.; Kang, L.; Lin, Z.; Wu, Y.; Chen, C. Analysis and Prediction of Mid-IR Nonlinear Optical Metal Sulfides with Diamond-like Structures. Coord. Chem. Rev. 2017, 333, 57−70. (8) Feng, J.; Hu, C.; Li, B.; Mao, J. LiGa2PS6 and LiCd3PS6: Molecular Designs of Two New Mid-Infrared Nonlinear Optical Materials LiGa2PS6 and LiCd3PS6: Molecular Designs of Two New Mid-Infrared Nonlinear Optical Materials. Chem. Mater. 2018, 30, 3901−3908. (9) Feng, J. H.; Hu, C. L.; Xu, X.; Li, B. X.; Zhang, M. J.; Mao, J. G. AgGa2PS6: A New Mid-Infrared Nonlinear Optical Material with a High Laser Damage Threshold and a Large Second Harmonic Generation Response. Chem. - Eur. J. 2017, 23, 10978−10982. (10) Zhou, M.; Yang, Y.; Guo, Y.; Lin, Z.; Yao, J.; Wu, Y.; Chen, C. Hg-Based Infrared Nonlinear Optical Material KHg4Ga5Se12 Exhibits Good Phase-Matchability and Exceptional Second Harmonic Generation Response. Chem. Mater. 2017, 29, 7993−8002. (11) Li, S. F.; Jiang, X. M.; Liu, B. W.; Yan, D.; Lin, C. S.; Zeng, H. Y.; Guo, G. C. Superpolyhedron-Built Second Harmonic Generation Materials Exhibit Large Mid-Infrared Conversion Efficiencies and High Laser-Induced Damage Thresholds. Chem. Mater. 2017, 29, 1796−1804. (12) Zhao, S.; Kang, L.; Shen, Y.; Wang, X.; Asghar, M. A.; Lin, Z.; Xu, Y.; Zeng, S.; Hong, M.; Luo, J. Designing a Beryllium-Free DeepUltraviolet Nonlinear Optical Material without a Structural Instability Problem. J. Am. Chem. Soc. 2016, 138, 2961−2964. (13) Li, C.; Yin, W.; Gong, P.; Li, X.; Zhou, M.; Mar, A.; Lin, Z.; Yao, J.; Wu, Y.; Chen, C. Trigonal Planar HgSe34‑ Unit: A New Kind of Basic Functional Group in IR Nonlinear Optical Materials with Large Susceptibility and Physicochemical Stability. J. Am. Chem. Soc. 2016, 138, 6135−6138. (14) Yin, W. L.; Iyer, A. K.; Li, C.; Yao, J. Y.; Mar, A. Noncentrosymmetric Chalcogenides BaZnSiSe4 and BaZnGeSe4 Featuring One-Dimensional Structures. J. Alloys Compd. 2017, 708, 414−421. (15) 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. New Metal Chalcogenides Ba4CuGa5Q12 (Q = S, Se) Displaying Strong Infrared Nonlinear Optical Response. Chem. Mater. 2013, 25, 2427−2433. (16) Lin, H.; Chen, L.; Zhou, L. J.; Wu, L. M. Functionalization Based on the Substitutional Flexibility: Strong Middle IR Nonlinear Optical Selenides AXII4XIII5Se12. J. Am. Chem. Soc. 2013, 135, 12914− 12921. (17) Yin, W.; Feng, K.; He, R.; Mei, D.; Lin, Z.; Yao, J.; Wu, Y. BaGa2MQ6 (M = Si, Ge; Q = S, Se): A New Series of Promising IR Nonlinear Optical Materials. Dalt. Trans. 2012, 41, 5653. (18) Mei, D.; Yin, W.; Feng, K.; Lin, Z.; Bai, L.; Yao, J.; Wu, Y. LiGaGe2Se6: A New IR Nonlinear Optical Material with Low Melting Point. Inorg. Chem. 2012, 51, 1035−1040. (19) Yao, J.; Mei, D.; Bai, L.; Lin, Z.; Yin, W.; Fu, P.; Wu, Y. BaGa4Se7: A New Congruent-Melting IR Nonlinear Optical Material. Inorg. Chem. 2010, 49, 9212−9216. (20) Yin, W. L.; Iyer, A. K.; Li, C.; Yao, J. Y.; Mar, A. Ba5CdGa6Se15, A Congruently-Melting Infrared Nonlinear Optical Material with Strong SHG Response. J. Mater. Chem. C 2017, 5, 1057−1063. (21) Fang, A. H.; Huang, F. Q.; Xie, X. M.; Jiang, M. H. LowTemperature Rapid Synthesis and Superconductivity of Fe-Based Oxypnictide Superconductors. J. Am. Chem. Soc. 2010, 132, 3260− 3261.

phase-matching, which matches well with the experimental results.

■

CONCLUSION Two new noncentrosymmetric isostructural chalcogenides K 2 BaSnS 4 and K 2 BaSnSe 4 have been discovered and characterized for the first time. They belong to the polar space group R3c and are characterized by ∞ 1[BaSnS4]2− (∞ 1[BaSnSe4]2−) tunnel structures which are separated by K+ cations. K2BaSnS4 possessed a large indirect band gap of 3.09 eV, which is favorable for high LDT. In the meanwhile, K2BaSnS4 maintains a moderate NLO response (0.5× AgGaS2) when the wavelength of pumping light is 2.09 μm. Moreover, K2BaSnS4 possesses type-I phase-matching capability. Therefore, the outstanding overall NLO performance makes K2BaSnS4 a potential candidate for IR NLO application.

■

ASSOCIATED CONTENT

S Supporting Information *

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.inorgchem.9b00967. Crystal structure of Ag2BaSnS4 and the space group and crystal system for compounds in A2BaMIVQ4 (I = Li, Na, K, Cu, and Ag; MIV= Si, Ge, and Sn; Q = S and Se) family (PDF) Accession Codes

CCDC 1868921 and 1868923 contain the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif, or by emailing [email protected], or by contacting The Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44 1223 336033.

■

AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected]. ORCID

Fei Liang: 0000-0002-4932-1329 Yangwu Guo: 0000-0002-2365-5873 Zheshuai Lin: 0000-0002-9829-9893 Jiyong Yao: 0000-0002-4802-5093 Notes

The authors declare no competing financial interest.

■

ACKNOWLEDGMENTS This research was supported by the National Natural Science Foundation of China (91622123, 51472251, 61675212, and 91622124).

■

REFERENCES

(1) Chung, I.; Kanatzidis, M. G. Metal Chalcogenides: A Rich Source of Nonlinear Optical Materials. Chem. Mater. 2014, 26, 849− 869. (2) Tell, B.; Kasper, H. M. Optical and Electrical Properties of AgGaS2 and AgGaSe2. Phys. Rev. B 1971, 4, 4455−4459. (3) Boyd, G. D.; Buehler, E.; Storz, F. G. Linear and Nonlinear Optical Properties of ZnGeP2 and CdSe. Appl. Phys. Lett. 1971, 18, 301−304. (4) Harasaki, A.; Kato, K. New Data on the Nonlinear Optical Constant, Phase-Matching, and Optical Damage of AgGaS2. Japanese 7124

DOI: 10.1021/acs.inorgchem.9b00967 Inorg. Chem. 2019, 58, 7118−7125

Article

Inorganic Chemistry

Nd, Sm, Gd-Ho) and Their Strong Nonlinear Optical Responses in Middle IR. J. Am. Chem. Soc. 2011, 133, 4617−4624. (41) Geng, L.; Cheng, W. D.; Zhang, W. L.; Lin, C. S.; Zhang, H.; Li, Y. Y.; He, Z. Z. BaM(BS3)S (M = Sb, Bi): Two New Thioborate Compounds with One-Dimensional Polymeric Chain Structure. Inorg. Chem. 2010, 49, 6609−6615. (42) Kleinman, D. A. Nonlinear Dielectric Polarization in Optical Media. Phys. Rev. 1962, 126, 1977−1979. (43) Isaenko, L.; Yelisseyev, A.; Lobanov, S.; Titov, A.; Petrov, V.; Zondy, J. J.; Krinitsin, P.; Merkulov, A.; Vedenyapin, V.; Smirnova, J. Growth and Properties of LiGaX2 (X = S, Se, Te) Single Crystals for Nonlinear Optical Applications in the Mid-IR. Cryst. Res. Technol. 2003, 38, 379−387. (44) Isaenko, L.; Yelisseyev, A.; Lobanov, S.; Krinitsin, P.; Petrov, V.; Zondy, J. J. Ternary Chalcogenides LiBC2 (B = In, Ga; C = S, Se, Te) for Mid-IR Nonlinear Optics. J. Non-Cryst. Solids 2006, 352, 2439−2443. (45) Yin, W.; Feng, K.; Hao, W.; Yao, J.; Wu, Y. Synthesis, Structure, and Properties of Li2In2MQ6 (M = Si, Ge; Q = S, Se): A New Series of IR Nonlinear Optical Materials. Inorg. Chem. 2012, 51, 5839−5843. (46) Li, G. M.; Liu, Q.; Wu, K.; Yang, Z. H.; Pan, S. L. Na2CdGe2Q6 (Q = S, Se): Two Metal-Mixed Chalcogenides with Phase-Matching Abilities and Large Second-Harmonic Generation Responses. Dalt. Trans. 2017, 46, 2778−2784. (47) Lekse, J. W.; Moreau, M. A.; McNerny, K. L.; Yeon, J.; Halasyamani, P. S.; Aitken, J. A. Second-Harmonic Generation and Crystal Structure of the Diamond-like Semiconductors Li2CdGeS4 and Li2CdSnS4. Inorg. Chem. 2009, 48, 7516−7518.

(22) Lin, X.; Zhang, G.; Ye, N. Growth and Characterization of BaGa4S7: A New Crystal for Mid-IR Nonlinear Optics. Cryst. Growth Des. 2009, 9, 1186−1189. (23) Kim, Y.; Seo, I.; Martin, S. W.; Baek, J.; Shiv Halasyamani, P.; Arumugam, N.; Steinfink, H. Characterization of New Infrared Nonlinear Optical Material with High Laser Damage Threshold, Li2Ga2GeS6. Chem. Mater. 2008, 20, 6048−6052. (24) Li, Z.; Jiang, X.; Zhou, M.; Guo, Y.; Luo, X.; Wu, Y.; Lin, Z.; Yao, J. Zn3P2S8: A Promising Infrared Nonlinear-Optical Material with Excellent Overall Properties. Inorg. Chem. 2018, 57, 10503− 10506. (25) Chung, I.; Song, J. H.; Jang, J. I.; Freeman, A. J.; Kanatzidis, M. G. Na2Ge2Se5: A Highly Nonlinear Optical Material. J. Solid State Chem. 2012, 195, 161−165. (26) Lin, H.; Li, B. X.; Chen, H.; Liu, P. F.; Wu, Li. M.; Wu, X. T.; Zhu, Q. L. Sr5ZnGa6S15: A New Quaternary Non-Centrosymmetric Semiconductor with a 3D Framework Structure Displaying Excellent Nonlinear Optical Performance. Inorg. Chem. Front. 2018, 5, 1458− 1462. (27) Li, G.; Wu, K.; Liu, Q.; Yang, Z.; Pan, S. Na2ZnGe2S6: A New Infrared Nonlinear Optical Material with Good Balance between Large Second-Harmonic Generation Response and High Laser Damage Threshold. J. Am. Chem. Soc. 2016, 138, 7422−7428. (28) Li, S.; Jiang, X.; Liu, B.; Yan, D.; Zeng, H.; Guo, G. Strong Infrared Nonlinear Optical Efficiency and High Laser Damage Threshold Realized in Quaternary Alkali Metal Sulfides Na2Ga2MS6 (M = Ge, Sn) Containing Mixed Nonlinear Optically Active Motifs. Inorg. Chem. 2018, 57, 6783−6786. (29) Sheldrick, G. M. A Short History of SHELX. Acta Crystallogr., Sect. A: Found. Crystallogr. 2008, 64, 112−122. (30) Kurtz, S. K.; Perry, T. T. A Powder Technique for the Evaluation of Nonlinear Optical Materials. J. Appl. Phys. 1968, 39, 3798−3813. (31) Kohn, W.; Sham, L. J. Self-Consistent Equations Including Exchange and Correlation Effects. Phys. Rev. 1965, 140, A1133− A1138. (32) Payne, M. C.; Teter, M. P.; Allan, D. C.; Arias, T. A.; Joannopoulos, J. D. Iterative Minimization Techniques for Ab Initio Total-Energy Calculations: Molecular Dynamics and Conjugate Gradients. Rev. Mod. Phys. 1992, 64, 1045−1097. (33) Segall, M. D.; Lindan, P. J. D.; Probert, M. J.; Pickard, C. J.; Hasnip, P. J.; Clark, S. J.; Payne, M. C. First-Principles Simulation: Ideas, Illustrations and the CASTEP Code. J. Phys.: Condens. Matter 2002, 14, 2717−2744. (34) Wu, K.; Yang, Z.; Pan, S. Na2BaMQ4 (M = Ge, Sn; Q = S, Se): Infrared Nonlinear Optical Materials with Excellent Performances and That Undergo Structural Transformations. Angew. Chem., Int. Ed. 2016, 55, 6713−6715. (35) Wu, K.; Zhang, B.; Yang, Z.; Pan, S. New Compressed Chalcopyrite-like Li2BaMIVQ4 (MIV = Ge, Sn; Q = S, Se): Promising Infrared Nonlinear Optical Materials. J. Am. Chem. Soc. 2017, 139, 14885−14888. (36) Nian, L.; Wu, K.; He, G.; Yang, Z.; Pan, S. Effect of Element Substitution on Structural Transformation and Optical Performances in I2BaMIVQ4 (I = Li, Na, Cu, and Ag; MIV = Si, Ge, and Sn; Q = S and Se). Inorg. Chem. 2018, 57, 3434−3442. (37) Huang, H.; Han, X.; Li, X.; Wang, S.; Chu, P. K.; Zhang, Y. Fabrication of Multiple Heterojunctions with Tunable Visible-LightActive Photocatalytic Reactivity in BiOBr-BiOI Full-Range Composites Based on Microstructure Modulation and Band Structures. ACS Appl. Mater. Interfaces 2015, 7, 482−492. (38) Simmons, E. L. Diffuse Reflectance Spectroscopy: A Comparison of the Theories. Appl. Opt. 1975, 14, 1380. (39) Wu, K.; Pan, S. Li2HgMS4 (M = Si, Ge, Sn): New Quaternary Diamond-Like Semiconductors for Infrared Laser Frequency Conversion. Crystals 2017, 7, 107. (40) Chen, M. C.; Li, L. H.; Chen, Y. B.; Chen, L. In-Phase Alignments of Asymmetric Building Units in Ln4GaSbS9 (Ln = Pr, 7125

DOI: 10.1021/acs.inorgchem.9b00967 Inorg. Chem. 2019, 58, 7118−7125