Dual-interface modification strategy via tautomeric UV absorber for efficient and UV stable planar perovskite solar cells

The functional layers and corresponding interfaces in perovskite solar cells (PSCs) have made great contributions to improving the efficiency and stability of the devices. However, the non-radiation recombination caused by interface defects and the intolerance of perovskite materials to ultraviolet (UV) light frequently results in the sharp deterioration of device performance. Herein, a holistic interface modification strategy through tautomeric UV absorbers has been proven to improve the efficiency and stability of PSCs, especially the photostability against UV light. It is found that the tautomer 2-hydroxy-4-methoxybenzophenone (BZP) molecule can not only be used as a defect passivator at the perovskite/electron transfer layer and hole transfer layer/perovskite in-terfaces simultaneously to reduce non-radiative recombination and optimize the interface energy-level arrangement for effective interface charge transfer. Meanwhile, BZP can also greatly reduce the decomposi-tion of perovskite film caused by ultraviolet rays and effectively improves the stability of the overall device. As a result, the champion PSC based-on SnO2-BZP/perovskite (BZP) achieves an impressing efficiency of 24.08% (0.09 cm2) and 17.64% (19.32 cm2) as well as significantly improved photostability compared with the controlled device. This work illustrates that the overall interface modification strategy can facilitate the fabri-cation of high-performance PSCs and promote their practical application.