Improved performance of perovskite solar cells by optimizing deposition parameters of TiO₂ compact layers

Abstract

~50 nm TiO₂ thin film was deposited by a facile spin-coating route as a compact layer (CL) of perovskite solar cells (PSCs). The deposition process was repeated several times for obtaining a better surface morphology, although the film thickness remained almost the same by tuning the precursor concentration. In this study, both the influences of precursor concentrations and deposition cycles were investigated on the final performance of PSC devices. Scanning electron microscopy and electrochemical impedance spectroscopy were employed to reveal the mechanism underlying the performance changes. After optimization, the best PCE of 14.73% was achieved in the devices made using the four-layer CLs, which might be attributed to both the improvement in electron conductivity and compactness of TiO₂ CLs.