Enhanced Performance of Perovskite Solar Cells by Using Ultrathin BaTiO₃ Interface Modification

Efficiency promotion has been severely constrained by charge recombination in perovskite solar cells (PSCs). Interface modification has been proved to be an effective way to reduce the interfacial charge recombination. In this work, a mesoporous TiO₂ (mp-TiO₂) layer was modified by an ultrathin BaTiO₃ layer to suppress charge recombination in PSCs. The ultrathin BaTiO₃ modification layer was prepared by the spin coating method using a barium salt solution. The concentration of the barium salt solution was optimized, and the effect of the BaTiO₃ modification layer on the performance of the cells was also investigated. The modification layer can not only successfully retard charge recombination but also effectively boost the rate of electron extraction at the interface, resulting in enhanced open-circuit voltage ( V_oc), short circuit current density ( J_sc), and fill factor. Furthermore, the hysteresis of the PSCs was also significantly reduced after the modification. By optimizing and employing the BaTiO₃ modification layer, the power conversion efficiency of the cells was increased from 16.13 to 17.87%.