Stoichiometric and stress factors effect investigation on MAPbI3 thin films

In this study, PbI₂ and MAPbI₃ films were deposited using the thermal evaporation method. The instability or partial stability of the deposited PbI₂ and MAPbI₃ films was evaluated by subjecting them to the stress factors outlined in the literature. XRD and UV–Vis analyses were conducted on the deposited PbI₂ and MAPbI₃ films. Finally, the changes in the materials resulting from exposure to stress factors such as laboratory atmosphere, prolonged light soaking aging state, UV aging state, and high-purity oxygen gas were characterized using the photoconductivity method. XRD analyses confirmed the formation of targeted crystal. Furthermore, the UV–Vis analyses revealed that the eV values of the MAPbI₃ structure are in accordance with those reported in the literature. Light soaking was so substantial that the subsequent UV aging state or O₂ aging state did not exceed or counteract the changes induced by light soaking aging state; their effects were not evident. These findings suggest that among the stress factors applied to the material, Light soaking aging state exerts the most significant influence.