Sulfurization of Electrodeposited Sb/Cu Precursors for CuSbS2: Potential Absorber Materials for Thin-Film Solar Cells

Aimei Zhao,Dongmei Xiang,Wei Li,Jinlian Bi,Bing Li,Liyong Yao,Yanping Wang,Zhuo Peng,Yujie Yuan,Yupeng Xing

doi:10.3389/fmats.2021.818596

Abstract

CuSbS2, as a direct bandgap semiconductor, is a promising candidate for fabricating flexible thin-film solar cells due to its low grain growth temperature (300°C–450°C). Uniform and highly crystalline CuSbS2 thin films are crucial to improving device performance. However, uniform CuSbS2 is difficult to obtain during electrodeposition and post-sulfurization due to the “dendritic” deposition of Cu on Mo substrates. In this study, Sb/Cu layers were sequentially pulse electrodeposited on Mo substrates. By adjusting the pulse parameters, smooth and uniform Sb layers were prepared on Mo, and a flat Cu layer was obtained on Sb without any dendritic clusters. A two-step annealing process was employed to fabricate CuSbS2 thin films. The effects of temperature on phases and morphologies were investigated. CuSbS2 thin films with good crystallinity were obtained at 360°C. As the annealing temperature increased, the crystallinity of the films decreased. The CuSbS2 phase transformed into a Cu3SbS4 phase with the temperature increase to 400°C. Finally, a 0.90% efficient solar cell was obtained using the CuSbS2 thin films annealed at 360°C.

Highlights

CuSbS2 is a direct bandgap material, which can be adjusted between 1.4 and 1.6 eV (Medina-Montes et al, 2018; Pal et al, 2020), and its optical absorption coefficient is greater than 105 cm−1 (Vinayakumar et al, 2019)
Sb/Cu metal layers were prepared on Mo substrates via the pulse current electrodeposition method
By adjusting the pulse parameters (Ton/Toff of 1:3, a pulse current density of 62.5 mA/cm2, and a pulse current frequency of 10,000 Hz), a compact and uniform Sb layer was prepared on the Mo substrate

Summary

Introduction

CuSbS2 is a direct bandgap material, which can be adjusted between 1.4 and 1.6 eV (Medina-Montes et al, 2018; Pal et al, 2020), and its optical absorption coefficient is greater than 105 cm−1 (Vinayakumar et al, 2019). It is an excellent alternative material for flexible photovoltaic devices due to its low grain growth temperature Various techniques, such as spray pyrolysis (Ramos Aquino et al, 2016; Wan et al, 2019; Zhou et al, 2021), ink (Banu et al, 2016; Banu et al, 2019), chemical bath deposition (Macías et al, 2017; LorancaRamos et al, 2018), sputtering (de Souza Lucas et al, 2016; Kang et al, 2018), evaporation (Rabhi et al, 2009; Wan et al, 2016), and electrodeposition (Septina et al, 2014; García et al, 2020), have been employed to fabricate CuSbS2 thin films. Macías et al, (2017) fabricated CuSbS2 thin films via a chemical bath method and treated the films at 380°C, achieving an encouraging efficiency of 0.6%. Zhang et al(2019) fabricated Mo/CuSbS2/CdS/ZnO/Al

Methods

Results

Conclusion