Fabrication of Cu2ZnSnS4 Thin Films from Ball-Milled Nanoparticle inks under Various Annealing Temperatures

Xianfeng Zhang; Engang Fu; Maoxi Zheng; Yuehui Wang

doi:10.3390/nano9111615

Fabrication of Cu₂ZnSnS₄ Thin Films from Ball-Milled Nanoparticle inks under Various Annealing Temperatures

Nanomaterials (Basel). 2019 Nov 14;9(11):1615. doi: 10.3390/nano9111615.

Authors

Xianfeng Zhang^{1

2}, Engang Fu³, Maoxi Zheng¹, Yuehui Wang^{1

4}

Affiliations

¹ Zhongshan Institute, University of Electronic Science and Technology of China, Zhongshan 528402, China.
² PANOTECH. INC. 7-13-6 Ginza, Tyouo-Ku, Toyo 1040061, Japan.
³ State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China.
⁴ Guangdong Engineering-Technology Research Center of Nano-Photoelectric Functional Films and Devices, Zhongshan 528402, China.

Abstract

Cu₂ZnSnS₄ (CZTS) has been recognized as a promising thin-film absorber material of chalcopyrite-related solar cells. A two-stage method for fabricating CZTS films using CZTS nanoparticles was developed. Nanocrystal inks fabricated by a ball-milling method was utilized to °C deposit CZTS precursors by spin-coating approach. The CZTS precursors were annealed in the sulfur atmosphere under different annealing temperatures ranging from 550 °C to 650 °C. Influences of annealing temperature on grain growth, composition, crystallinity, and photovoltaic properties of CZTS films were characterized. With the increase of annealing temperature, grain growth was enhanced, while the sulfur atomic ratio fist increased then decreased. The crystallinity of the films was significantly improved after the annealing, and the obvious peak of the secondary phase of ZnS, were observed from the X-ray diffraction results, when the annealing temperature increased to 625 °C. However, the secondary phase was not detected from the surface Raman spectrum. Through comparing the Raman spectrum of different areas of the CZTS film, secondary phases of ZnS and SnS were observed, indicating the decomposition of CZTS films, due to the high temperature. The highest conversion efficiency of 7.5% was obtained when the annealing temperature was 600 °C.

Keywords: Cu2ZnSnS4 solar cell; annealing; secondary phase.