Antisolvent Engineering for Microstructural Improvement of Lead Free Solar Absorber Material

Lead free halide materials are seeking attention owing to their astonishing optoelectronic properties accompanied with better stability and less toxicity. Silver bismuth halides being ecofriendly and seen as potential candidates for photovoltaic applications but they are still struggling with power conversion. To address this issue here we have used antisolvent engineering to improve film morphology and tested the absorber material in an inverted solar cell for the fisrt time with device architecture: ITO/NiO/AgBiI₄/C₆₀/BCP/Ag. The efficiency was improved from 0.5% to 1.3% for the solar cell based on absorber layer fabricated via chloroform assisted antisolvent solvent spin casting method. The microstructural improvement was proven by a thorough analysis with SEM and AFM. This study has demonstrated that low boiling antisolvent can assist less polar antisolvent to improve the microstructure of the thin films which ultimately resulted in enhancement of PCE in AgBiI₄ inverted solar cell.