Enhancement of photovoltaic performance of perovskite solar cells by modification of the interface between the perovskite and mesoporous TiO2 film

By dipping the mesoporous TiO 2 film in Sr 2+ solutions and subsequent annealing, a modification layer of SrTiO 3 has been formed on the surface of the mesoporous TiO 2 film, and the effect of modification on the photovoltaic characteristics of the perovskite solar cells has been studied detailedly. The XPS and TEM results verified the existence and nature of the SrTiO 3 modification layer. Benifiting from the TiO 2 surface modification, the morphology of perovskite film and light absorption of the CH 3 NH 3 PbI 3 absorber have been improved effectively, and a faster charge transfer has also been achieved between the CH 3 NH 3 PbI 3 perovskite layer and the modified TiO 2 . As a result, an average conversion efficiency of 11.4% has been achieved in the perovskite solar cell based on the modified mesoporous TiO 2 by 10   mM Sr 2+ solution, and it increases approximately by 46% in comparison with the photovoltaic efficiency of 7.8% of the perovskite solar cell based the bare mesoporous TiO 2 layer.