DMF-Based Large-Grain Spanning Cu2 ZnSn(Sx ,Se1- x )4 Device with a PCE of 11.76

Yubo Cui; Mengyang Wang; Peizhe Dong; Shuangshuang Zhang; Junjie Fu; Libo Fan; Chaoliang Zhao; Sixin Wu; Zhi Zheng

doi:10.1002/advs.202201241

DMF-Based Large-Grain Spanning Cu₂ ZnSn(S_x ,Se_1- _x )₄ Device with a PCE of 11.76

Adv Sci (Weinh). 2022 Jul;9(20):e2201241. doi: 10.1002/advs.202201241. Epub 2022 Apr 28.

Authors

Yubo Cui^{1

2}, Mengyang Wang^{1

3}, Peizhe Dong^{1

3}, Shuangshuang Zhang¹, Junjie Fu³, Libo Fan^{1

2}, Chaoliang Zhao¹, Sixin Wu³, Zhi Zheng¹

Affiliations

¹ Key Laboratory of Micro-Nano Materials for Energy Storage and Conversion of Henan Province, Institute of Surface Micro and Nano Materials, College of Chemical and Materials Engineering, Xuchang University, Xuchang, Henan Province, 461000, P. R. China.
² School of Materials Science and Engineering, Henan Polytechnic University, Jiaozuo, Henan Province, 454000, P. R. China.
³ Key Laboratory for Special Functional Materials of Ministry of Education, Henan University, Kaifeng, Henan Province, 475004, P. R. China.

Abstract

A main concern of the promising DMF-based Cu₂ ZnSn(S_x ,Se_1- _x )₄ (CZTSSe) solar cells lies in the absence of a large-grain spanning structure, which is a key factor for high open-circuit voltage (V_oc ) and power conversion efficiency (PCE). A new strategy to achieve CZTSSe large-grain spanning monolayer is proposed, by taking advantage of the synergistic optimization with a Cu²⁺ plus Sn²⁺ redox system and pre-annealing temperatures. A series of structural, morphological, electrical, and photoelectric characterizations are employed to study the effects of the pre-annealing temperatures on absorber qualities, and an optimized temperature of 430 ℃ is determined. The growth mechanism of the large-grain spanning monolayer and the effect of redox reaction rate are carefully investigated. Three types of absorber growth mechanisms and a concept of critical temperature are proposed. The devices based on this large-grain spanning monolayer suppress the recombination of carriers at crystal boundaries and interfaces. The champion device exhibits a high V_oc (>500 mV) and PCE of 11.76%, which are both the maximum values among DMF-based solar cells at the current stage.

Keywords: Cu2ZnSn(Sx,Se1-x)4 (CZTSSe); dimethylformamide (DMF); large-grain spanning; photoelectric property; redox reaction.

Abstract

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