Suppressing Dewetting in Ultrathin Metal Films via SnO_<i>x</i> Cladding Layer for Efficient Semitransparent Perovskite Solar Cells

Ultrathin metal films (UTMFs) are promising electrode candidates for semitransparent perovskite solar cells (St-PSCs). However, deposited UTMFs often exist in metastable or unstable states, leading to dewetting or aggregation at elevated temperatures, which compromises the stability of the St-PSCs. Here, we investigate the stability behavior of UTMFs in St-PSCs during operational conditions and discover that the solid-state dewetting of UTMFs can occur even at room temperature and atmospheric pressure. By introducing an additional tin oxide (SnOx) cladding layer on the top of UTMFs via atomic layer deposition (ALD), the stability of UTMFs and St-PSCs is significantly improved. Our St-PSCs with UTMFs/SnOx electrodes achieve a promising power conversion efficiency (PCE) of 20.1%. Encapsulated devices retain 95% of the initial efficiency after 500 h continuous operation under 1 sun illumination.