Structural and photo physical investigation of single-source evaporation of CsFAPbI3 and FAPbI3 perovskite thin films

Thermal vacuum deposition is a stimulating technique for upscaling perovskite solar cells. The operational complexity of multi-source vapor deposition (MSVD) in achieving stoichiometric perovskite layers may impede its implementation. The single-source vapor deposition (SSVD) method has recently emerged as an alternative for MSVD due to its inherent functionality. Here for the first time, we demonstrate the successful SSVD approach in fabricating pure CsFAPbI₃ and FAPbI₃ thin films from pre-synthesized perovskite powders. A series of structural, optoelectronic, and morphological investigations were carried out to optimize the phase purity and shelf-life of the deposited thin films. Furthermore, we probed the perovskite layer compatibility with various underlayers; we noted the organic underlayer displayed superiority over the metal oxide layer, suggesting the suitability of <em>p-i-n</em> devices over the <em>n-i-p</em>.