Enhanced performance of mesostructured perovskite solar cells with a composite Sn4+-doped TiO2 electron transport layer

Recently, perovskite solar cells (PSCs) have attracted more attention. TiO2 as the most common electron transfer material in PSCs has been improved by a serious of methods. In this study, a simple method was used to improve the traditional compact TiO2 properties by doping with Sn4+. It demonstrated that the conductivity of the TiO2 film could be well improved and the band-gap shifted from 3.65 to 3.55 eV with the introduction of Sn ions. The Sn–O–Ti bond was observed in the Sn:TiO2 film according to the results of XPS. The mesostructured PSCs based on Sn:TiO2 exhibited negligible J-V hysteresis behavior, and the Jsc of the device increased distinctly. The power conversion efficiency (PCE) of the Sn:TiO2 device was improved from 14.86 to 17.11%, compared with the reference device.