Tellurium-Based Double Perovskites A2TeX6 with Tunable Band Gap

Subscriber access provided by Gothenburg University Library

Letter

Tellurium-based Double Perovskites A2TeX6 with Tunable Bandgap and Long Carrier Diffusion Length for Optoelectronic Applications Dianxing Ju, Xiaopeng Zheng, Jun Yin, Zhiwen Qiu, Bekir Turedi, Xiaolong Liu, Yangyang Dang, Bingqiang Cao, Omar F. Mohammed, Osman M. Bakr, and Xutang Tao ACS Energy Lett., Just Accepted Manuscript • DOI: 10.1021/acsenergylett.8b02113 • Publication Date (Web): 10 Dec 2018 Downloaded from http://pubs.acs.org on December 11, 2018

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 21 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

ACS Energy Letters

Tellurium-based Double Perovskites A2TeX6 with Tunable Bandgap and Long Carrier Diffusion Length for Optoelectronic Applications Dianxing Ju,1,§ Xiaopeng Zheng,

2,3,§

Jun Yin,3 Zhiwen Qiu,4 Bekir Türedi,

2,3

Xiaolong Liu,1

Yangyang Dang,1 Bingqiang Cao,4,5* Omar F. Mohammed3, Osman M. Bakr,2,3,* Xutang Tao1,* 1State

Key Laboratory of Crystal Materials & Institute of Crystal Materials, Shandong

University, No. 27 Shanda South Road, Jinan 250100, P. R. China 2KAUST

Catalysis Center, King Abdullah University of Science and Technology (KAUST),

Thuwal, 23955-6900, Saudi Arabia 3Division

of Physical Sciences and Engineering, King Abdullah University of Science and

Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia 4Materials

Research Center for Energy and Photoelectrochemical Conversion, School of Material

Science and Engineering, University of Jinan, Jinan 250022, Shandong, China. 5Department

§

of Physics and Institute of Laser, Qufu Normal University, Qufu, 273165, China

These authors contributed equally.

ACS Paragon Plus Environment

1

ACS Energy Letters 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 2 of 21

ABSTRACT Lead-free hybrid perovskites have attracted immense interest as environmentally friendly light absorbers. Here, we report on tellurium (Te)-based double perovskites A2TeX6 (A= MA, FA or BA, X = Br- or I-, MA= CH3NH3, FA= CH(NH2)2, BA= benzylamine) as potentially active materials for optoelectronic devices. This perovskites exhibit a tunable bandgap (1.42 eV-2.02 eV), a low trap density (～1010 cm-3), and a high mobility (～ 65 cm2 V-1 s-1). Encouragingly, the MA2TeBr6 single crystal with a bandgap of 2.00 eV possesses a long carrier lifetime of ~6 μs and corresponding carrier diffusion lengths of ~38 μm, which are ideal characteristics for a material for photodetectors and tandem solar cells. Moreover, A2TeX6 perovskites are relatively robust in ambient conditions, being stable for at least two months without showing any signs of phase change. Our findings bring to the forefront a family of lead-free Te-based perovskites for non-toxic perovskite optoelectronics.

TOC GRAPHICS

Organic-inorganic halide perovskites (OIHPs) have emerged as one of the most promising nextgeneration photoelectric materials, being widely explored in photodetectors,1,

2

light emitting

diodes,3, 4 lasers,5, 6 X-ray detectors7, field effect transistors (FETs),8, 9 and solar cells, 10-16 due to


2

Page 3 of 21 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

ACS Energy Letters

their outstanding attributes, including tunable bandgap, long carrier diffusion length, high mobility, and low-temperature solution processability. The power conversion efficiency (PCE) of perovskite solar cells has rapidly jumped to 23.3% within nine years since the first reported PCE of 3.8% in 2009.

17-19

However, most of the fast photo- or radiation-detectors, high efficiency

solar cells, and high-performance LEDs are based on Pb-containing perovskites, which are generally regarded as harmful to the human health and entail special device disposing or recycling protocols after the device failure.20 Continuing efforts have been devoted to discovering lead free perovskites for solar cells and detectors. Sn has been applied to replace the Pb to form less toxic perovskites such as MASnI3, FASnI3,

21-23

which yielded solar cells with efficiencies of over 9%.24 Unfortunately, the ease of

oxidization of the Sn2+ to Sn4+ in ambient condition results in the fast degradation of the Sn-based perovskite devices. The Bi/Sb-based materials and double perovskites also gained significant attention; solar cells using (CH3NH3)3Bi2I9 and Cs3Bi2I9 achieved PCEs of 1.64% and 1.09%, respectively,25-28 and while radiation detectors exhibited a low detection limit.29 However, the large bandgap of Bi/Sb-based perovskite makes these materials of little use for applications in single junction solar cells and long-wavelength photo-detetors.30,

31

Therefore, it is still

challenging to develop a stable lead-free perovskite with a broad, tunable bandgap and ideal optoelectronic attributes for high-performance perovskite devices. In this study, we report a family of tellurium (Te)-based double perovskites A2TeX6 (A= MA, FA or BA, X = Br− or I−) with bandgaps that are broadly tunable (in the wavelength ranges relevant to solar cells and detectors), superior electronic attributes, and promising stability. The results highlight the potential of Te-based double perovskites for non-toxic perovskite devices either the detectors or the solar cells.


3


Page 4 of 21

The MA2TeI6 single crystal was first prepared by hydrothermal process, as shown in Figure 1a and b, with the reaction of tellurium oxide (TeO2) and methylamine hydrochloride in the solution of hydroiodic acid (HI) at 220 oC for 24 h. Phase purity was observed by the X-ray diffraction (XRD) which matches well with the calculated result of the corresponding XRD pattern, and all the peaks in MA2TeI6 were different from that of raw materials TeI4 and MAI, and no other impurities were found (Figure 1c). The single crystal of MA2TeBr6 was grown by the top seeded solution growth (TSSG) method (Figure 1d). After one month’s growth, the red, shiny, and centimeter-sized MA2TeBr6 single crystal was obtained, as shown in Figure 1e. The MA2TeBr6 also exhibit a pure phase demonstrated by XRD pattern (Figure 1f). Besides, a series of narrow band gap single crystals, including FA2TeI6, FA2TeBr6 and BA2TeI6 (BA= benzylamine), were synthesized, as shown in Figure S1. The corresponding XRD patterns were shown in Figure S2.

Figure 1. MA2TeI6 single crystal was obtained by hydrothermal method. (a) Preparation, (b) MA2TeI6 single crystal photograph, (c) The powder XRD patterns of the sample was consistent with the calculated XRD patterns of the single crystals. MA2TeBr6 single crystals obtained by


4

Page 5 of 21 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

ACS Energy Letters

top seeded solution growth (TSSG) method in ambient atmosphere. (d) Preparation, (e) MA2TeBr6 single crystal photograph, (f) The powder XRD patterns of the samples were consistent with the calculated XRD patterns of the single crystals. We next studied the growth mechanism and crystal structure from the aspect of fundamental crystallography. Take the MA2TeI6 single crystal for example; the MA2TeI6 single crystal exhibits an obvious screw dislocation growth mechanism, or spiral growth, described by BurtonCabrera-Frank (BCF) theory,

32, 33

as shown in Figure S3. The mechanism for spiral growth

includes the deposition of atoms onto the terraces, and the subsequent capture and incorporation of the diffusing atoms at the step edge.34 Similar crystal growth mechanism of MA2TeBr6 single crystal was shown in Figure S3e and f. The single crystal XRD patterns indicate that both the crystal structure of MA2TeI6 and MA2TeI6 belongs to the cubic Fm-3m space group.35 Their crystal structures are shown in Figure 2. Due to the disorder of the group CH3NH3, C and N atoms in the C/N structural unit cannot be determined completely, thereafter the N atom was used to present the disorder group CH3NH3.36 All of the I-Te bond lengths in the structure of MA2TeI6 were found to be 2.948 Å, as well the MA2TeBr6 of 2.712 Å. Six I or Br atoms form an octahedron and Te, indicating the symmetry of the {TeI6} or {TeBr6} octahedral structural unit along the different directions. Moreover, we also got the similar crystal structures of cubic Fm3m space group for FA2TeI6 and FA2TeBr6. However, the BA2TeI6 exhibited a different monoclinic crystal system and P21/c space group, with sheet morphology and a black color, as shown in Figure S4. The detailed single-crystal parameters are presented in Table S1.


5


Page 6 of 21

Figure 2. Ball-and-stick diagrams of crystal structures and the {TeI6} and {TeBr6} octahedral structure units in the (a-c) MA2TeI6, (d-f) MA2TeBr6. The C and N elements represent the disordered CH3NH3 group; hydrogen atoms bonded to the C or N atoms were omitted for clarity. The bond lengths of {TeI6} and {TeBr6} octahedral structure units were 2.948 Å and 2.712 Å, respectively. The UV-Vis diffuse reflectance spectra of these samples are given in the Figure 3 (a, b) and Figure S5, which shows the broad absorption, especially for the MA2TeI6 and FA2TeI6 with their absorption about 843 nm and 871 nm, respectively. Surprisingly, the BA2TeI6 exhibits a significant spectral red-shifted of 282 nm with an absorption up to 812 nm, which is much broader than that of BA2PbI4.37, 38 In general, light harvesting up to 800 nm (near-infrared region: NIR region) should be achieved to realize high-efficiency single junction solar cells and NIR photodetectors.39 Thus, the A2TeI6 (A=MA, FA, BA) exhibit a potential application in single junction solar cells and long wavelength photodetector. Compared with the MAPbBr3,

40

the


6

Page 7 of 21 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

ACS Energy Letters

color of MA2TeBr6 and FA2TeBr6 single crystals are deepening with the band gap of 2.00 eV and 2.02 eV, as shown in Figure 3b and Figure S5b. Both the PL spectra of MA2TeI6 and MA2TeBr6 are displayed in Figure S6a and b, and match well with their UV spectra. The corresponding time-resolved photoluminescence (TRPL) spectra were used to characterize their transport properties, which were fitted by the equation of Y = A + B1exp(-t/1) + B2exp(-t/2) + B3exp(-t/3) (Figure 3 c, d) and included the fast and slow part. As we know, the fast carrier lifetime represents the carrier recombination at the crystal surface due to trap states, while the slow part of carrier recombination is caused from the fewer defects in bulk crystal.

40-42

Interestingly, MA2TeBr6 shows a much longer lifetime, especially for the slow part (τ3=5958 ns). It should be noted that the lifetime of the single crystal is also much longer than that of the powder, because of the fewer surface states and defects, as shown in Figure S6c and d. Similarly, the PL and TRPL spectra of FA2TeI6, FA2TeBr6 and BA2TeI6 and all their detailed fitted result were also shown in the Figure S7-S8. Here, all the bandgap and carrier lifetime of the samples were summarized in Table 1. The corresponding comparisons with other reported perovskites were summarized in Table S2.


7


Page 8 of 21

Figure 3. UV-vis diffuse reflectance spectroscopy plots for (a) MA2TeI6 and (b) MA2TeBr6. Insets: corresponding tangent plots displaying the extrapolated optical band gaps. Time-resolved photoluminescence spectra for (c) MA2TeI6 and (d) MA2TeBr6 single crystals.


8

Page 9 of 21 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

ACS Energy Letters

Figure 4. (a) Orbital hybridization of Te and X (X = Br, I) in A2TeX6 perovskites; and calculated electronic bands and projected density of states (PDOS) at PBE+SOC level of theory for (b) MA2TeI6, (c) MA2TeBr6, (d) FA2TeI6, (e) FA2TeBr6, and (f) BA2TeI6. The calculated electronic bands and projected density using Perdew-Burke-Ernzerhof (PBE) functional without and with spin-orbit coupling (SOC) are shown in Figure S9 and Figure 4, respectively. We found that all A2TeX6 perovskites (A = MA, FA, BA; X = Br, I) show the indirect bandgap nature between Γ and R symmetry points of the Brillouin zone. The calculated values are given in Table 1: MA2TeI6 (1.47 eV), MA2TeBr6 (2.25 eV), FA2TeI6 (2.44 eV),


9


Page 10 of 21

FA2TeBr6 (2.11 eV) and BA2TeI6 (1.69 eV) which are in very good agreement with the experimental results deduced from the absorption spectra. The PBE functional with SOC retained the band curvature but resulted in more conduction band degeneracies and a slightly reduced bandgaps. The projected density of states shows that the dominant contributions to the top of the valence band are from Te-5s and Br-4p or I-5p, whereas the bottom of the conduction band mainly consists of Te-5p and Br-4p or I-5p, indicating that the absorption continuum might be due to inter band electronic transitions around the Γ point, with the main contribution being from Te4+(5s)Br-(4p)→Te4+(5p)Br-(4p) or Te4+(5s)I-(5p)→Te4+(5p)I-(5p). The extracted values of electron/hole effective mass (m*e/h) along different directions are shown in Table S3 of the Supporting Information. We found that i) m*e values of all A2TeX6 perovskites are much smaller than their m*h, and ii) MA2TeI6 and FA2TeI6 have smaller m*e values than cases of MA2TeBr6 and FA2TeBr6, indicating both MA2TeI6 and FA2TeI6 are potentially electron-transporting materials.


10

Page 11 of 21 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

ACS Energy Letters

Table 1. Experimental and calculated band gaps (PBE and PBE+SOC level of theory) and carrier lifetimes of A2TeX6. Eg (exp, eV)

Eg (cal, eV)

1 (ns)

2 (ns)

3 (ns)

MA2TeI6 powder

1.47

1.42 (1.25)

0.56

5.46

--

MA2TeI6 single crystal

1.47

-

0.58

2.84

20.12

MA2TeBr6 powder

2.00

2.25 (2.12)

119.48

618.81

2501.91

MA2TeBr6 single crystal

2.00

-

269.7

1399

5958

FA2TeI6 powder

1.42

1.44 (1.27)

0.36

5.11

--

FA2TeBr6 powder

2.02

2.11 (1.94)

210.00

979.22

3378.67

BA2TeI6 powder

1.53

1.69 (1.47)

294.63

1762.36

--

Materials

The UPS spectrum was used to determine the work function of MA2TeI6 with the value of 4.77 eV, as shown in Figure 5a-b, and further demonstrated the optimal electrode of silver. However, to reduce the effect of AgI,

43

we use Au as the electrode. According to the UPS

spectrum and UV-vis-NIR diffuse reflectance spectra (Figure 3), we listed the energy levels of MA2TeI6 and other carrier transport materials in Figure 5c, which provide the guidance of the samples for photoelectric applications and space charge-limited current (SCLC) test.44-49 Then, the related trap density and carrier mobility of MA2TeI6 single crystal based on the SCLC test were estimated according to our and other previous report. 31, 40, 50, 51 It can be seen from Figure 5d that the trap state densities of MA2TeI6 single crystal were of the order of 1010 cm-3. The related carrier mobility can be compared with that of MAPbI3 single crystal in the same order, measured by SCLC.49 The detailed information for the mobilities of MA2TeI6 under the different frequency was listed on the Table S4. The trap density of MA2TeI6 polycrystalline thin film was also derived from SCLC (Figure 5e) which is the same magnitude with that of the MAPbI3 (～


11


Page 12 of 21

1015 to ～ 1016 cm-3) thin film.52 The similar estimate of MA2TeBr6 single crystal and thin film (0.96 mm and thickness 10 nm) was also shown in Figure S10 and Table S5. Their resistivity (rho) of the thin films was also carried out by Hall Effect measurements at room temperature, as shown in Figure S11. Here, the diffusion lengths of both the MA2TeI6 and MA2TeBr6 single crystals were also estimated with the given Boltzmann’s constant (kB) and temperature (T=300 K), based on their carrier mobility and lifetime, using the following relation: 53

𝐿𝐷 =

k B T  μ e

(1)

The best-case and worst-case diffusion length of both the MA2TeI6 and MA2TeBr6 single crystals are corresponding to the slow and fast transient carrier lifetime, respectively. The details of the diffusion lengths including the best case and worst case varied with frequency were listed into Table S6. Importantly, the long diffusion lengths, such as the 38.19 μm for MA2TeBr6 single crystals, make them an ideal candidate for tandem solar cells and sensitive photo- or radiationdetectors. Here, kinds of reported hybrid perovskite single crystals with their carrier mobility, trap density and carrier diffusion lengths were summarized in Table S7. ,


12

Page 13 of 21 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

ACS Energy Letters

Figure 5. (a) The UPS spectrum of the MA2TeI6 thin film coated on ITO glass, measured under 5 eV bias. The work function values are calculated according to the formula hν-Φ = EF-Ecut off. (b) The energy band structure diagram of MA2TeI6. (c) Energy levels of MA2TeI6 and other materials relevant to photovoltaic devices with perovskite absorbers.43-48 (d) Dark current-voltage


13


Page 14 of 21

curve of MA2TeI6 single crystals for space charge limited current analysis. (e) Dark currentvoltage curve of MA2TeI6 thin film for space charge limited current analysis. The air stability of the perovskites is an important factor to guarantee the reliable output of the devices. As the degradation of hybrid perovskites, such as MAPbI3 and MASnI3, is quite sensitive to moisture and oxygen, and their assembled devices degraded obviously when measured under ambient conditions, which lead to an unwanted decrease in efficiency, and restrict the outdoor applications of PSCs. However, compared with the MAPbI3 and MASnI3, the MA2TeI6 and MA2TeBr6 are relatively robust in ambient conditions, being stable for even two months without any phase change. This can be determined by the XRD patterns. Figure S12a and b show the powder XRD patterns of MA2TeI6 and MA2TeBr6 single crystals after exposure to the ambient atmosphere for two months. Clearly, all the diffraction patterns match well with the initial sample. The high stability was also expressed in the thin film of MA2TeI6. The thin film was difficult to obtain by spin coating process but was easy deposited by thermal evaporation process with a dark and smooth surface, shown in Figure S12c. The morphology for MA2TeI6 film is quite uniform and compact determined by the FESEM (Figure S12d), which is necessary for perovskite devices to deliver high performance. More importantly, the film is quite stable with the absorption area about ～680 nm (thickness ～100 nm), even after expose to the air for one month, as exhibited in the Figure S12e and S13, further exhibited a promising stable application in high performance photovoltaic devices. Similarly, the good stability was also exhibited from the FA2TeI6, FA2TeI6 and BA2TeI6, as shown in Figure S14. The MA2TeI6 and MA2TeBr6 single crystals also exhibit good thermal-stability, which was determined by the thermogravimetric analysis. Figure S15a and b show the TGA and DSC curves of MA2TeI6 and MA2TeBr6 single crystals. The decomposition temperature of MA2TeI6


14

Page 15 of 21 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

ACS Energy Letters

and MA2TeBr6 single crystals are about 200 oC and 270 oC, exhibiting a good thermal stability. The DSC at low temperatures ranging from 120 K to 400 K was also measured to determine phase transition temperature, as shown in Figure S15c and S15d. It can be seen clearly that there are no obvious phase changes for MA2TeI6 single crystals. On the contrary, two phase changes are shown obviously in the Figure S15d at 277 K and 150 K of MA2TeBr6,

54

which need to be

further researched. In summary, we have successfully obtained centimetre-sized Pb-free A2TeX6 (A= MA, FA or BA, X = Br− or I−, BA= benzylamine) double perovskite single crystals. Their crystal structures, growth mechanism, and optoelectronic properties were characterized and discussed. These Te-based perovskites show promising optoelectronic properties, paving the way for nontoxic perovskite devices with high performance and stability. ASSOCIATED CONTENT Supporting Information. The Supporting Information is available free of charge on the ACS Publications website. Experimental Section; Single crystal photographs; The powder XRD patterns of the samples; The photos of MA2TeBr6 single crystals under the polarizing microscope; Ball-and-stick stick diagrams of crystal structures of samples; UV-vis diffuse reflectance spectroscopy plots of samples; First principle calculation of samples; Steady-state photoluminescence spectroscopy of FA2TeI6, FA2TeBr6 and BA2TeI6.Time-resolved photoluminescence spectra for FA2TeI6, FA2TeBr6 and BA2TeI6 powder. Dark current-voltage curves of MA2TeBr6 single crystal and thin film; Resistivity measurement of MA2TeBr6 thin film by Hall Effect at room temperature. The typical UV-vis diffuse reflectance spectroscopy plots for MA2TeI6 thin film. XRD patterns


15


Page 16 of 21

of MA2TeI6 thin film by thermal evaporation process with different annealing time. The powder XRD patterns of the samples after exposed to the air for one month. TGA and DSC dates for MA2TeI6 and MA2TeBr6. Table S1-S5 including the crystal data (CCDC 1837660-1837664), calculated effective mass (×m0) for hole and electron of samples without and with SOC effects at GGA/PBE level of theory, the trap-state density, the carrier mobility and the diffusion length of MA2TeI6 and MA2TeBr6 single crystals at different frequency at different frequency.

AUTHOR INFORMATION Corresponding Author * [email protected]; *[email protected]; *[email protected] Author Contributions D. Ju and X. Tao conceived and designed the project. D. Ju and X. Zheng prepared and characterized the properties. J. Yin and B. Türedi assisted on the first principle calculation. Z. Qiu prepared the thin film. X. Liu and Y. Dang assisted on the measurement of UPS. B. Cao, O. and F. Mohammed contributed to the discussion and advised D. Ju and X. Zheng. X. Tao and O. M. Bakr supervised the entire project. D. Ju wrote the first draft of the paper. All of the authors discussed the results and contributed to the writing of the paper. Notes The authors declare no competing financial interest. ACKNOWLEDGMENT


16

Page 17 of 21 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

ACS Energy Letters

D. Ju and X. Zheng contributed equally to this work. This work was supported by the National Natural Science Foundation of China (grant nos. 51321091, 51772170, 51272129, 51227002), National key Research and Development Program of China (Grant No.2016YFB1102201), the Program of Introducing Talents of Disciplines to Universities in China (111 Project 2.0 (Grant No: BP2018013), and King Abdullah University of Science and Technology (KAUST). We greatly thank Xiufeng Cheng and Zhaozhen Cao for their help in thermal properties and TRPL measurements, respectively.

REFERENCES (1) Dou, L.; Yang, Y.; You, J.; Hong, Z.; Chang, W. H.; Li, G.; Yang, Y. Solution-processed hybrid perovskite photodetectors with high detectivity. Nat. Commun, 2014, 5, 5404. (2) Yang, T. Y.; Gregori, G.; Pellet, N.; Grätzel, M.; Maier, J. The significance of ion conduction in a hybrid organic-inorganic lead-iodide-based perovskite photosensitizer. Angew. Chem. 2015, 127, 8016-8021. (3) Tan, Z. K.; Moghaddam, R. S.; Lai, M. L.; Docampo, P.; Higler, R.; Deschler, F.; Price, M.; Sadhanala, A.; Pazos, L. M.; Credgington, D.; et al. Bright light-emitting diodes based on organometal halide perovskite. Nat. Nanotech., 2014, 9, 687-692. (4) Kim, Y. H.; Cho, H.; Heo, J. H.; Kim, T. S.; Myoung, N. S.; Lee, C. L.; Im, S. H.; Lee, T. W. Multicolored organic/inorganic hybrid perovskite light-emitting diodes. Adv. Mater., 2015, 27, 1248. (5) Zhu, H.; Fu, Y.; Meng, F.; Wu, X.; Gong, Z.; Ding, Q.; Gustafsson, M. V.; Trinh, M. T.; Jin, S.; Zhu, X.Y. Lead halide perovskite nanowire lasers with low lasing thresholds and high quality factors. Nat. Mater., 2015, 14, 636-642. (6) Xing, J.; Liu, X. F.; Zhang, Q.; Ha, S. T.; Yuan, Y. W.; Shen, C.; Sum, T. C., Xiong, Q. Vapor phase synthesis of organometal halide perovskite nanowires for tunable room-temperature nanolasers. Nano Lett. 2015, 15, 4571-4577. (7) Wei, H.; Fang, Y.; Mulligan, P.; Chuirazzi, W.; Fang, H. H.; Wang, C.; Ecker, B. R.; Gao, Y.; Loi, M. A.; Cao, L.; et al. Sensitive X-ray detectors made of methylammonium lead tribromide perovskite single crystals. Nat. Photonics, 2016, 10, 333-339. (8) Chen, J.; Zhou, S.; Jin, S.; Li, H.; Zhai, T. Crystal organometal halide perovskites with promising optoelectronic applications. J. Mater. Chem. C, 2016, 4, 11-27.


17


Page 18 of 21

(9) Chin, X. Y.; Cortecchia, D.; Yin, J.; Bruno, A.; Soci, C. Lead iodide perovskite light-emitting field-effect transistor. Nat. Commun, 2015, 6, 7383. (10) Wang, Z.; Lin, Q.; Chmiel, F. P.; Sakai, N.; Herz, L. M.; Snaith, H. J. Efficient ambient-airstable solar cells with 2D-3D heterostructured butylammonium-caesium-formamidinium lead halide perovskites. Nat. Energy, 2017, 2, 17135. (11) Koh, T. M.; Shanmugam, V.; Schlipf, J.; Oesinghaus, L.; Buschbaum, P. M.; Ramakrishnan, N.; Swamy, V.; Mathews, N.; Boix, P. P.; Mhaisalk, S. G. Nanostructuring mixed-dimensional perovskites: A route toward tunable, efﬁcient photovoltaics. Adv. Mater. 2016, 28, 3653-3661. (12) Zheng, X.; Chen, B.; Dai, J.; Fang, Y.; Bai, Y.; Lin, Y.; Wei, H.; Zeng, Xiao C.; Huang, J., Defect passivation in hybrid perovskite solar cells using quaternary ammonium halide anions and cations. Nat. Energy. 2017, 2, 17102. (13) Stranks, S. D.; Eperon, G. E.; Grancini, G.; Menelaou, C.; Alcocer, M. J.; Leijtens, P. T.; Herz, L. M.; Petrozza, A.; Snaith, H. J. Electron-hole diffusion lengths exceeding 1 micrometer in an organometal trihalide perovskite absorber. Science, 2013, 342, 341-344. (14) Zheng, X.; Deng, Y.; Chen, B.; Wei, H.; Xiao, X.; Fang, Y.; Lin, Y.; Yu, Z.; Liu, Y.; Wang, Q. et al. Dual functions of crystallization control and defect passivation enabled by sulfonic zwitterions for stable and effcient perovskite solar cells, Adv. Mater. 2018, 1803428. (15) Jeon, N. J.; Noh, J. H.; Kim,Y. C.; Yang, W. S.; Ryu, S.; Seok, S. Il. Solvent engineering for high-performance inorganic-organic hybrid perovskite solar cells. Nat. Mater. 2014, 13, 897903. (16) Snaith, H. J. Perovskites: The emergence of a new era for low-cost, high-efficiency solar cells. J. Phys. Chem. Lett. 2013, 4, 3623-3630. (17) Kojima, A.; Teshima, K.; Shirai, Y.; Miyasaka, T. Organometal halide perovskites as visible-light sensitizers for photovoltaic cells. J. Am. Chem. Soc. 2009, 131, 6050-6051. (18) Zhao, Z.; Gu, F.; Rao, H.; Ye, S.; Liu, Z.; Bian, Z.; Chunhui Huang, C. Metal halide perovskite materials for solar cells with long-term stability, Adv. Energy Mater. 2018, 1802671. (19) Yang, W. S.; Park, B.; Jung, E. H.; Jeon, N. J. Iodide management in formamidinium-leadhalide–based perovskite layers for efficient solar cells. Science, 2017, 356, 1376-1379. (20) Polman, A.; Knight, M.; Garnett, E. C.; Ehrler, B.; Sinke, W. C. Photovoltaic materials: Present efficiencies and future challenges. Science, 2016, 352, 6283. (21) Ozaki, M.; Katsuki,Y.; Liu, J.; Handa,T.; Nishikubo, R.; Yakumaru,S.; Hashikawa,Y.; Murata, Y.; Saito, T.; Shimakawa, Y.; et al. Solvent-coordinated tin halide complexes as purified precursors for tin-based perovskites. ACS Omega, 2017, 2, 7016-7021. (22) Hao, F.; Stoumpos, C. C.; Cao, D. H.; Chang, R. P. H.; Kanatzidis, M. G. Lead-free solidstate organic–inorganic halide perovskite solar cells. Nat. Photonics, 2014, 8, 489-494.


18

Page 19 of 21 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

ACS Energy Letters

(23) Hao, F.; Stoumpos, C. C.; Guo, P.; Zhou, N.; Marks, T. J.; Chang, R. P. H.; Kanatzidis, M. G. Solvent-mediated crystallization of CH3NH3SnI3 films for heterojunction depleted perovskite solar cells. J. Am. Chem. Soc. 2015, 137, 11445-11452. (24) Shao, S.; Liu, J.; Portale, G.; Fang, H.; Blake, G.; Brink, G.; Koster, L.; Loi, M. Highly reproducible Sn-based hybrid perovskite solar cells with 9% efficiency. Adv. Energy Mater. 2017, 1702019. (25) Park, B. W.; Philippe, B.; Zhang, X.; Rensmo, H.; Boschloo, G.; Johansson, E. M. J. Bismuth based hybrid perovskites A3Bi2I9 (A: methylammonium or cesium) for solar cell application. Adv. Mater. 2015, 27, 6806-6813. (26) Zhang, Z.; Li, X.; Xia, X.; Wang, Z.; Huang, Z.; Lei, B.; Gao, Y. High-quality (CH3NH3)3Bi2I9 film-based solar cells: Pushing efficiency up to 1.64%. J. Phys. Chem. Lett. 2017, 8, 4300-4307. (27) Zuo, C.; Ding, L. Lead-free perovskite materials (NH4)3Sb2IxBr9-x. Angew. Chem. Int. Ed. 2017, 56, 6528-6532. (28) Jiang, F.; Yang, D.; Jiang, Y.; Liu, T.; Zhao, X.; Ming, Y.; Qin, F.; Fan, J.; Han, H.; Zhang, L.; et al. Chlorine-incorporation-induced formation of the layered phase for antimony-based lead-free perovskite solar cells. J. Am. Chem. Soc. 2018, 140, 1019-1027. (29) Pan, W.; Wu, H.; Luo, J.; Deng, Z.; Ge C.; Chen, C.; Jiang, X.; Yin, W.; Niu , G.; Zhu, L.; et al. Cs2AgBiBr6 single-crystal X-ray detectors with a low detection limit. Nat. Photo, 2017, 11, 726-732. (30) Zhou, Z. Y.; Ju, M.; Garces, H. F.; Krause, A. R.; Ji, F.; Cui, G.; Zeng, X.; Padture, N. P.; Pang, S. Thin-film transformation of NH4PbI3 to CH3NH3PbI3 perovskite: A methylamineinduced conversion–healing process. Angew. Chem., Int. Ed., 2016, 55, 14723-14727. (31) Ju, D. X.; Zhao, T.; Dang, Y.; Zhang, G.; Hu, X.; Cui, D.; Tao, X. Gas induced conversion of hybrid perovskite single crystal to single crystal for great enhancement of their photoelectric properties. J. Mater. Chem. A, 2017, 5, 21919-21925. (32) Porsin, A. V.; Rogoznikov, V. N.; Kulikov, A. V.; Salanov, A. N.; Serkova, A. N. Crystallization of aluminum hydroxide in a sodium aluminate solution on a heterogeneous surface. Cryst. Growth Des. 2017, 17, 4730-4738. (33) Wu, J.; Hu, Z.; Jin, Z.; Lei, S.; Guo, H.; Chatterjee, K.; Zhang, J.; Yang, Y.; Li, B.; Liu, Y.; et al. Spiral growth of SnSe2 crystals by chemical vapor deposition. Adv. Mater. Interfaces, 2016, 1600383. (34) Myers-Beaghton, A. K.; Vvedensky, D. D. Generalized Burton-Cabrera-Frank theory for growth and equilibration on stepped surfaces. Phys. Rev. A, 1991, 44, 2457-2468. (35) Furukawa, Y.; Kiriyama, H.; Ikeda, R. Molecular motion in mathylmmonium hexahalotellurates (IV) as studied by means of the pulsed nuclear magnetic resonance, Bull. Chem. Soc. Jpn, 1981, 54, 103-108.


19


Page 20 of 21

(36) Dang, Y.; Zhou, Y.; Liu, X.; Ju, D.; Xia, S.; Xia, H.; Tao, X. Formation of hybrid perovskite tin iodide single crystals by top-seeded solution growth. Angew. Chem. Int. Ed. 2016, 128, 34473450. (37) Li, R.; Yi, C.; Ge, R.; Zou, W.; Cheng, L.; Wang, N.; Wang, J.; Huang, W. Roomtemperature electroluminescence from two-dimensional lead halide perovskites. Appl. Phys. Lett. 2016, 109, 151101. (38) Dang, Y.; Liu, Y.; Sun, Y.; Yuan, D.; Liu, X.; Lu, W.; Liu, G.; Xia, H.; Tao, X. T. Bulk crystal growth of hybrid perovskite material CH3NH3PbI3. CrystEngComm, 2015, 17, 665-670. (39) Ogomi, Y.; Morita, A.; Tsukamoto, S.; Saitho, T.; Fujikawa, N.; Shen, Q.; Toyoda, T.; Yoshino, K.; Pandey, S. S.; Ma, T. CH3NH3SnxPb(1–x)I3 perovskite solar cells covering up to 1060 nm. J. Phys. Chem. Lett. 2014, 5, 1004-1011. (40) Ju, D.; Dang, Y.; Zhu, Z.; Liu, H.; Chueh, C.; Li, X.; Wang, L.; Hu, X.; Jen, A. K.-Y; Tao, X. Tunable band gap and long carrier recombination lifetime of stable mixed CH3NH3PbxSn1−xBr3 Single Crystals. Chem. Mater. 2018, 5, 1556-1565. (41) Shi, D.; Adinolfi, V.; Comin, R.; Yuan, M.; Alarousu, E.; Buin, A.; Chen, Y.; Hoogland, S.; Rothenberger, A.; Katsiev, K.; et al. Low trap-state density and long carrier diffusion in organolead trihalide perovskite single crystals. Science 2015, 347, 519-522. (42) Huang, Y.; Li, L.; Liu, Z.; Jiao, H.; He, Y.; Wang, X.; Zhu, R.; Wang, D.; Sun, J.; Chen, Q.; et al. The intrinsic properties of FA(1−x)MAxPbI3 perovskite single crystals. J. Mater. Chem. A 2017, 5, 8537-8544. (43) Akbulatov, A. F.; Frolova, L. A.; Griffn, M. P.; Gearba, I. R.; Dolocan, A.; Bout, D.; Tsarev, S.; Katz, E. A.; Shestakov, A. F.; Stevenson, K. J.; et al. Effect of electron-transport material on light-induced degradation of inverted planar junction perovskite solar cells. Adv. Energy Mater. 2017, 7, 1700476. (44) Slavney, A. H.; Hu, T.; Lindenberg, A. M.; Karunadasa, H. I. A bismuth-halide double perovskite with long carrier recombination lifetime for photovoltaic applications. J. Am. Chem. Soc. 2016, 138, 2138-2141. (45) Boix, P. P.; Nonomura, K.; Mathews, N.; Mhaisalkar, S. G. Current progress and future perspectives for organic/inorganic perovskite solar cells cells, Mater. Today, 2014, 17, 16-24. (46) Zhao, Y. Y.; Liu, T.; Ren, F.; Duan, J.; Wang, Y.; Yang, X.; Li, Q.; Tang, Q. Organic holetransporting materials for 9.32%-efficiency and stable CsPbBr3 perovskite solar cells, Mater. Chem. Front., 2018 2, 2239-2244. (47) Liao, W. Q.; Zhao, D.; Yu, Y.; Grice, C.; Wang, C.; Cimaroli, A.; Schulz, P.; Meng, W.; Zhu, K.; Xiong, R. G.; et al. Lead‐free inverted planar formamidinium tin triiodide perovskite solar cells achieving power conversion efficiencies up to 6.22%, Adv. Mater. 2016, 28, 93339340 (48) Gao, P.; Gratzel, M.; Nazeeruddin, M. K. Organo-halide lead perovskites for photovoltaic


20

Page 21 of 21 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

ACS Energy Letters

applications, Energy Environ. Sci., 2014, 7, 2448-2463 (49) Zhu, Z.; Bai, Y.; Liu, X.; Chueh, C. C.; Yang, S.; Jen, A. K.-Y. Enhanced efficiency and stability of inverted perovskite solar cells using highly crystalline SnO2 nanocrystals as the robust electron-transporting layer, Adv. Mater. 2016, 28, 6478-6484. (50) Saidaminov, M. I.; Abdelhady, A. L.; Murali, B.; Alarousu, E.; Burlakov, V. M.; Peng, W.; Dursun, I.; Wang, L.; He, Y.; Maculan, G. High-quality bulk hybrid perovskite single crystals within minutes by inverse temperature crystallization. Nat. Commun. 2015, 6, 7586. (51) Han, Q.; Bae, S. H.; Sun, P.; Hsieh, Y. T.; Yang, Y. M.; Rim, Y. S.; Zhao, H.; Chen, Q.; Shi, W.; Li, G. Single crystal formamidinium lead iodide (FAPbI3): Insight into the structural, optical, and electrical properties. Adv. Mater. 2016, 28, 2253-2258. (52) Zhang, D.; Cui, B.; Zhou, C.; Li, L.; Chen, Y.; Zhou, N.; Xu, Z.; Li, Y.; Zhou, H.; Chen, Q. Reduction of intrinsic defects in hybrid perovskite films via precursor purification. Chem. Commun., 2017, 53, 10548-10511. (53) Zhumekenov, A.; Saidaminov, M.; Haque, M.; Alarousu, E.; Sarmah, S.; Murali, B.; Dursun, I.; Miao, X.; Abdelhady, A.; Wu, T.; et al. Formamidinium lead halide perovskite crystals with unprecedented long carrier dynamics and diffusion length. ACS Energy Lett. 2016, 1, 32-37. (54) Kume, Y.; Ikeda, R.; Nakamura, D. Phase transitions of methylammonium hexahalotellurates (IV) as revealed by the nuclear quadrupole resonance of halogens. J. Phy. Chem, 1978, 82, 1926-1930.


21

Tellurium-Based Double Perovskites A2TeX6 with Tunable Band Gap

Recommend Documents