Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV24)
DOI: https://doi.org/10.29363/nanoge.hopv.2024.102
Publication date: 6th February 2024
Following the advances in increasing power conversion efficiencies of hybrid organic-inorganic metal-halide perovskite solar cells (PSCs), recent research efforts have focused more on enhancing their long-term stability. Among the various factors that impact the device’s lifetime, an important role is played by humidity-driven degradation, which, within hours, can significantly lower the starting performance of PSCs.
The influence of humidity has been attributed to hydrogen bonds forming between water molecules in moist air and the nitrogen atoms in widely used ammonium-based organic cations like methylammonium (MA) and formamidinium (FA). To mitigate this process, we introduce sulfonium- and sulfoxonium-based cations like trimethyl sulfonium (TMS) and trimethyl sulfoxonium (TMSO) at the top and buried interface of the perovskite active layer. By examining the interfaces using advanced spectroscopic and microscopic methods and evaluating the performance and stability of the devices, we demonstrate that this approach leads to significantly enhanced moisture stability. Importantly, the strategy can be applied to various perovskite compositions without altering the recipe or structure of the bulk perovskite.