Ultrafast self-trapping of photoexcited carriers sets the upper limit on antimony trisulfide photovoltaic devices

Zhaoliang Yang; Xiaomin Wang; Yuzhong Chen; Zhenfa Zheng; Zeng Chen; Wenqi Xu; Weimin Liu; Yang Michael Yang; Jin Zhao; Tao Chen; Haiming Zhu

doi:10.1038/s41467-019-12445-6

Ultrafast self-trapping of photoexcited carriers sets the upper limit on antimony trisulfide photovoltaic devices

Nat Commun. 2019 Oct 4;10(1):4540. doi: 10.1038/s41467-019-12445-6.

Authors

Zhaoliang Yang¹, Xiaomin Wang², Yuzhong Chen¹, Zhenfa Zheng³, Zeng Chen¹, Wenqi Xu⁴, Weimin Liu⁴, Yang Michael Yang⁵, Jin Zhao³, Tao Chen⁶, Haiming Zhu^{7

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Affiliations

¹ Centre for Chemistry of High-Performance & Novel Materials, Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang, 310027, China.
² CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei, Anhui, 230026, China.
³ Department of Physics, University of Science and Technology of China, Hefei, Anhui, 230026, China.
⁴ School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
⁵ State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou, 310027, Zhejiang, China.
⁶ CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei, Anhui, 230026, China. tchenmse@ustc.edu.cn.
⁷ Centre for Chemistry of High-Performance & Novel Materials, Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang, 310027, China. hmzhu@zju.edu.cn.
⁸ State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou, 310027, Zhejiang, China. hmzhu@zju.edu.cn.

Abstract

Antimony trisulfide (Sb₂S₃) is considered to be a promising photovoltaic material; however, the performance is yet to be satisfactory. Poor power conversion efficiency and large open circuit voltage loss have been usually ascribed to interface and bulk extrinsic defects By performing a spectroscopy study on Sb₂S₃ polycrystalline films and single crystal, we show commonly existed characteristics including redshifted photoluminescence with 0.6 eV Stokes shift, and a few picosecond carrier trapping without saturation at carrier density as high as approximately 10²⁰ cm^-3. These features, together with polarized trap emission from Sb₂S₃ single crystal, strongly suggest that photoexcited carriers in Sb₂S₃ are intrinsically self-trapped by lattice deformation, instead of by extrinsic defects. The proposed self-trapping explains spectroscopic results and rationalizes the large open circuit voltage loss and near-unity carrier collection efficiency in Sb₂S₃ thin film solar cells. Self-trapping sets the upper limit on maximum open circuit voltage (approximately 0.8 V) and thus power conversion efficiency (approximately 16 %) for Sb₂S₃ solar cells.

Publication types

Research Support, Non-U.S. Gov't