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

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 Cu₂ZnSn(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.