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Frontiers of Optoelectronics

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Front. Optoelectron.    2019, Vol. 12 Issue (4) : 352-364    https://doi.org/10.1007/s12200-019-0907-4
RESEARCH ARTICLE
Antimony doped Cs2SnCl6 with bright and stable emission
Jinghui LI1, Zhifang TAN2, Manchen HU1, Chao CHEN2, Jiajun LUO1, Shunran LI1, Liang GAO1, Zewen XIAO1, Guangda NIU1(), Jiang TANG2()
1. Wuhan National Laboratory for Optoelectronics (WNLO), Huazhong University of Science and Technology, Wuhan 430074, China
2. School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China
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Abstract

Lead halide perovskites, with high photoluminescence efficiency and narrow-band emission, are promising materials for display and lighting. However, the lead toxicity and environmental sensitivity hinder their potential applications. Herein, a new antimony-doped lead-free inorganic perovskites variant Cs2SnCl6:xSb is designed and synthesized. The perovskite variant Cs2SnCl6:xSb exhibits a broadband orange-red emission, with a photoluminescence quantum yield (PLQY) of 37%. The photoluminescence of Cs2SnCl6:xSb is caused by the ionoluminescence of Sb3+ within Cs2SnCl6 matrix, which is verified by temperature dependent photoluminescence (PL) and PL decay measurements. In addition, the all inorganic structure renders Cs2SnCl6:xSb with excellent thermal and water stability. Finally, a white light-emitting diode (white-LED) is fabricated by assembling Cs2SnCl6:0.59%Sb, Cs2SnCl6:2.75%Bi and Ba2Sr2SiO4:Eu2+ onto the commercial UV LED chips, and the color rendering index (CRI) reaches 81.
Keywords perovskite      lead-free      antimony doping      orange-red emission     
Corresponding Author(s): Guangda NIU,Jiang TANG   
Just Accepted Date: 25 March 2019   Online First Date: 16 May 2019    Issue Date: 30 December 2019
 Cite this article:   
Jinghui LI,Zhifang TAN,Manchen HU, et al. Antimony doped Cs2SnCl6 with bright and stable emission[J]. Front. Optoelectron., 2019, 12(4): 352-364.
 URL:  
https://academic.hep.com.cn/foe/EN/10.1007/s12200-019-0907-4
https://academic.hep.com.cn/foe/EN/Y2019/V12/I4/352
Fig.1  (a) XRD patterns of Cs2SnCl6:xSb powders with representative Sb content. The inset is the crystal structure of vacancy ordered double perovskite Cs2SnCl6. Dark purple spheres: Cl; tawny spheres: Cs; gray spheres: Sn. (b) XPS survey spectrum for Cs2SnCl6:0.59%Sb. (c) Calculated polyhedron of the chemical potential region where Cs2SnCl6 is stable against possible competitive phases. (d) Calculated formation enthalpies (DH) of neutral Sbi and SbSn as a function of the chemical potentials (DmCs, DmSn), where (DmCs, DmSn) moves along the F-E-D-C-B-A-G-F lines in (c)
Fig.2  (a) Optical absorption spectrum of Cs2SnCl6:0.59%Sb, the insets show the images of Cs2SnCl6:0.59%Sb under the natural light (left) and UV irradiation (right). (b) Excitation and photoluminescence spectra of Cs2SnCl6:0.59%Sb
x lex/nm lem/nm FWHM/nm Stokes shift/nm PLQY
0 N/A N/A N/A N/A N/A
0.20% 365 601 101 236 25.9%
0.41% 364 601 102 237 28.3%
0.59% 365 602 101 237 37.0%
0.89% 365 604 102 239 32.0%
0.98% 366 602 100 236 21.9%
Tab.1  Photophysical properties of Cs2SnCl6:xSb at room temperature (x is the content of antimony; lex is the wavelength at the excitation maximum; lem is the wavelength at the emission maximum)
Fig.3  (a) Temperature-dependent photoluminescence spectra of Cs2SnCl6:0.59%Sb. (b) Schematic diagram of luminescence process in Cs2SnCl6:xSb. (c) Schematic of the potential energy curves of Cs2SnCl6:xSb in a configuration space. (d) PL decay curve of Cs2SnCl6:0.59%Sb bulk crystals (lex = 365 nm, lem = 602 nm). The red curve is a fit to the experimental data with a double exponential decay function. (e) Excitation spectra of PL monitored at different emission wavelengths. (f) Emission spectra of PL monitored at different excitation wavelengths
Fig.4  (a) TGA and DSC of Cs2SnCl6:0.59%Sb. (b) PL stability of Cs2SnCl6:0.59%Sb by illuminating with UV light (365 nm). The measurements were conducted in air without any encapsulation. (c) PL stability of Cs2SnCl6:0.59%Sb after immersed into deionized water for different durations
Fig.5  (a) Luminescence spectra from Cs2SnCl6:0.59%Sb-based LEDs with cold white emission and (inset) photo of an operating LED. (b) CIE coordinates and CCTs corresponding to white-LED device (white star) and Cs2SnCl6:0.59%Sb crystals (red triangle). (c) Emission spectra of white-LED device at different driving currents
feeding concentrations ICP-OES-determined concentrations
0.99% 0.20%
4.76% 0.41%
9.09% 0.59%
16.66% 0.89%
23.08% 0.98%
  Table S1 Feeding concentrations and ICP-OES-determined concentrations of Sb/(Sb+Sn)
  Fig. S1 High-resolution X-ray diffraction analysis and Rietveld refinements of Sb-doped Cs2SnCl6 with different content of antimony. The structural parameters and refinement statistics were included in Table S1
x a/Å Rp/% Rwp/% χ2
0.00% 10.37371 4.91 6.95 4.63
0.20% 10.37373 5.31 8.09 6.55
0.41% 10.38144 5.26 8.00 6.27
0.59% 10.38175 4.51 6.51 4.10
0.89% 10.38232 4.77 6.97 4.75
0.98% 10.38246 4.78 6.79 4.53
  Table S2 Refined lattice parameters of Cs2SnCl6:xSb, x represent the Sb/(Sb+Sn) molar ratios determined by ICP-OES
  Fig. S2 High-resolution XPS spectra of Cs2SnCl6:0.59%Sb and peak fitting for (a) tin and (b) antimony, respectively
  Fig. S3 Optical absorption spectra of Sb-doped Cs2SnCl6
  Fig. S4 Temperature-dependent photoluminescence spectra and the corresponding Gaussian fitting results
  Fig. S5 Anti-water stability comparison among Cs2SnCl6:Sb3+, (C9NH20)2SbCl5 and CsPbBr3@Cs4PbBr6 (i.e., the core-shell structure of CsPbBr3-Cs4PbBr6). The latter two samples are reproduced from literature by ourselves
  Fig. S6 Air stability of Pb-free perovskites Cs2SnCl6:0.59%Sb
  Fig. S7 XRD pattern for Cs2SnCl6:0.59%Sb3+ sample after exposed to air for one week. The inverted triangles mark represent the X-Ray Diffraction peaks for SbOCl
  Fig. S8 Operational LED stability of Pb-free perovskites Cs2SnCl6:xSb
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