Minimizing open-circuit voltage loss in perovskite solar cells through synergistic energy-level grading and lattice matching

MAPbI₃ perovskite solar cells (PSCs) exhibit a theoretical open-circuit voltage (V_OC) of approximately 1.3 V, and minimizing V_OC loss is crucial for enhancing their performance. Herein, we focus on MAPbI₃ PSCs to inhibit the interfacial charge recombination and voltage loss through synergistic energy-level grading and lattice matching. The synthesized SrTiO₃ nanocubes were incorporated into the TiO₂ electron transport layer to effectively achieve optimal energy alignment with the conduction band of MAPbI₃, to reduce charge carrier energy loss, and improve carrier extraction. Furthermore, the small lattice mismatch between the perovskite structures of SrTiO₃ and MAPbI₃ promoted the growth of high-quality perovskite films with reduced defect density. As a result, the V_OC of the MAPbI₃ PSCs was increased to 1.17 V, and the power conversion efficiency reached 22.19%. This work provides an effective approach to interface optimization to emphasize the energy-level grading and lattice matching in minimizing V_OC loss and improving the performance of MAPbI₃ PSCs.