Insights into optoelectronic properties of anti-solvent treated perovskite films

The remarkable performance in perovskite solar cells over the past few years primarily stemmed from an improvement in perovskite film composition and morphology. Antisolvent treatment of perovskite films is one such widely adopted method where a solvent other than that used for precursor solution is introduced to facilitate rapid crystallization of perovskite crystals and to obtain a homogeneous pin-hole free film. Various reports are published recently to understand solvent extraction mechanism, electrical properties and the effect of antisolvent treatment of perovskite film on device performance and stability. Herein, we report some more insights on the charge carrier dynamics, crystallinity and more importantly, the change in energy levels of antisolvent treated perovskite films. The UV–vis absorption, photoluminescence, and photoelectron spectroscopy measurements revealed a downward shift in energy levels of MAPbI3 perovskite when treated with an antisolvent. The energy level shift favoured interfacial charge transfer and resulted in remarkable open-circuit voltage ~1.08 V and photoconversion efficiency 8.21% up from 0.61 V and 1.3% for a non-treated film, respectively for devices prepared at ambient conditions.