SOLVENT ENGINEERING FOR ENHANCED CRYSTALLIZATION, STABILITY AND ELECTRONIC PROPERTIES OF CH3NH3PBI3 PEROVSKITES

Abstract

Perovskite materials are promising for solar cells due to their high absorption, long carrier diffusion lengths, and tunable band gaps. However, their instability under ambient conditions hinders commercialization. This study investigates the crystallization kinetics and moisture-induced degradation of CH3NH3PbI3 films synthesized via solvent engineering. Perovskite precursors were dissolved in DMF or a DMF: DMSO (4:1 v/v) mixture, and films were analyzed using GIWAXS, SEM, UV-Vis, PL, SPV, and DFT. Films from DMF: DMSO showed no PbI2 signatures, suggesting improved phase purity and vertical growth, while those from DMF alonet5 exhibited PbI2 signature at q = 0.9 Å 1 due to rapid nucleation. Humidity exposure increased PbI2 formation, confirming degradation. The determined band gap was ~1.57 eV, with an efficiency of 8.5% and a disorder energy of 26 meV. These results highlight the critical role of solvent selection in optimizing perovskite film stability and performance for scalable solar cell applications.