12.86% Efficient Cu₂ZnSn(S,Se)₄ Thin Film Solar Cells via Inkjet Printing with 2‐Methoxyethanol‐Based Air‐Stable Precursor Ink

Abstract Inkjet printing is a promising and scalable drop‐on‐demand deposition technique for cost‐effective mass production of thin film solar cells. However, the efficiency of inkjet‐printed Cu 2 ZnSn(S,Se) 4 (CZTSSe) solar cells based on dimethyl sulfoxide (DMSO) precursor ink is inferior to state‐of‐the‐art spin‐coated devices. Therefore, it is crucial to improve the efficiencies of inkjet‐printed CZTSSe solar cells. In this work, inkjet printing technique is used to deposit flat and continuous CZTSSe thin films in ambient air using a novel 2‐methoxyethanol‐based ink that shows long‐term stability in the air and better wettability compared to the conventional used DMSO‐based ink. In addition, the effects of printing resolution on the structure, morphology, electrical and photovoltaic properties of CZTSSe light harvesting layer are investigated. Eventually, a remarkable device efficiency of 12.86% is achieved, surpassing the reported record efficiency for CZTSSe solar cells based on inkjet printing by ≈40%. Notably, this inkjet printing method allows for the significant reduction of preparation cost of CZTSSe thin films by improving the raw material utilization, thus paving a more viable pathway toward the sustainable development of CZTSSe solar cells.