Thin film AgBiS2 solar cells with over 10 % power conversion efficiency enabled by vapor-assisted solution process treatment

Recently, thin film photovoltaic solar energy has grown rapidly with new materials for achieving high conversion efficiency and long-term stability. Especially, silver bismuth sulfide (AgBiS2) nanocrystal-based quantum-dots have emerged as viable absorber for cost-effective photovoltaic. However, a thick AgBiS2 quantum-dots layer always faces the dilemma of entailing the charge carrier collection and trap-assisted recombination. Here we show a vapor-assisted solution process to fabricate high crystallinity submicron-grain AgBiS2 films. The resultant devices with small active area (0.06 cm2) achieved a record-breaking power conversion efficiency of 10.20 % and large active area (1.00 cm2) achieved an efficiency of 9.53 % under 100 mW cm−2 standard AM 1.5 global sunlight simulation, both of which are the highest reported for thin film AgBiS2 solar cells to date. Notably, the solar cells based on submicron-grain AgBiS2 thin films showed an exceptional durability, maintaining over 94 % of the initial PCE for 3,000 h in ambient air, along with excellent stability under extreme conditions, including exposure to 85 °C and 85 % relative humidity.