Performance Enhancement of Mesoporous TiO₂-Based Perovskite Solar Cells by SbI₃ Interfacial Modification Layer

TiO₂ is commonly used as an electron-transporting material in perovskite photovoltaic devices due to its advantages, including suitable band gap, good photoelectrochemical stability, and simple preparation process. However, there are many oxygen vacancies or defects on the surface of TiO₂ and thus this affects the stability of TiO₂-based perovskite solar cells under UV light. In this work, a thin (monolayer) SbI₃ modification layer is introduced on the mesoporous TiO₂ surface and the effect at the interface between of TiO₂ and perovskite is monitored by using a quartz crystal microbalance system. We demonstrate that the SbI₃-modified TiO₂ electrodes exhibit superior electronic properties by reducing electronic trap states, enabling faster electron transport. This approach results in higher performances compared with electrodes without the SbI₃ passivation layer. CH₃NH₃PbI₃ perovskite solar cells with a maximum power conversion efficiency of 17.33% in air, accompanied by a reduction in hysteresis and enhancement of the device stability, are reported.