High-efficiency Cu2ZnSn(S,Se)4 solar cells fabricated through a low-cost solution process and a two-step heat treatment

Shih Hsiung Wu, Chia Wen Chang, Hui Ju Chen, Chuan Feng Shih, Yu Yun Wang, Chou Cheng Li, Sheng Wen Chan

Research output: Contribution to journalArticlepeer-review

37 Citations (Scopus)


A method for fabricating high-efficiency Cu2ZnSn(S,Se)4 (CZTSSe) solar cells is presented, and it is based on a non-explosive, low-cost, and simple solution process followed by a two-step heat treatment. 2-Methoxyethanol was used as a solvent, and Cu, Zn, Sn, chloride salts, and thiourea were used as solutes. A CZTSSe absorber was prepared by sulfurising and then selenising an as-coated Cu2ZnSnS4 (CZTS) film. Sulfurisation in a sulfur vapour filled furnace for a long time (2 h) enhanced the crystallisation of the as-coated CZTS film and improved the stability of the CZTS precursor, and selenisation promoted further grain growth to yield a void-free CZTSSe film. Segregation of Cu and S at the grain boundaries, the absence of a fine-grain bottom layer, and the large grain size of the CZTSSe absorber were the main factors that enhanced the grain-to-grain transport of carriers and consequently the short-circuit current (Jsc) and efficiency. The efficiency of the CZTS solar cell was 5.0%, which increased to 10.1% after selenisation. For the 10.1% CZTSSe solar cell, the external quantum efficiency was approximately 80%, the open-circuit voltage was 450 mV, the short-circuit current was 36.5 mA/cm2, and the fill factor was 61.9%.

Original languageEnglish
Pages (from-to)58-66
Number of pages9
JournalProgress in Photovoltaics: Research and Applications
Issue number1
Publication statusPublished - 2017 Jan 1

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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