Exploring degradation mechanisms in CZTSSe solar cells for harsh environmental conditions

Copper Zinc Tin Sulfide Selenide (CZTSSe) solar cells have emerged as a promising alternative to established photovoltaic technologies due to their use of earth-abundant, non-toxic materials and potential for cost-effective manufacturing. However, understanding the operational and long-term stability of CZTSSE solar cells is crucial for their commercialization, particularly under harsh environmental conditions. Stability studies on CZTSSe solar cells often lack standardization and long-term data, which hampers the effective understanding of degradation mechanisms. Our research focuses on examining the aging effects in CZTSSe solar cells over an extended period of three months to identify key degradation pathways. Solar cell devices with a structure of Glass/Mo/CZTSSe/CdS/i-ZnO/ITO/metal contact were fabricated. Samples were exposed to outdoor testing facility in Qatar for three months to understand the degradation pathway. As found, no degradation was observed within the absorber layer whereas a gradual decomposition of the buffer layer has been identified, as confirmed by XPS, TEM and ToF-SIMS analyses. These findings provide valuable insights into the degradation mechanisms of CZTSSe solar cells and highlight the importance of addressing stability challenges for long-term deployment, especially in harsh environments. Furthermore, the study underscores the need for optimized materials and device structures to enhance the longevity and commercial viability of CZTSSe solar cell technology.