Efficient and stable perovskite solar cells by interface engineering at the interface of electron transport layer/perovskite

Perovskite materials owing to their unique properties for photovoltaic applications, widely have been considered by researchers as a desirable candidate for solar cell devices. State-of-the-Art perovskite solar cells (PSCs) recorded a power conversion efficiency (PCE) of 25.7%. Herein, we focused on improving both the stability and photovoltaic performance of PSCs via an interface engineering at the mesoporous titanium dioxide (mp-TiO2)/perovskite interface. We employed 8-Oxychinoline (8-Oxin) material to tailor the surface of mp-TiO2 and prepare a favorable plane for deposition of perovskite. The 8-Oxin material reduced charge transfer resistance (Rct) and increased charge recombination resistance (Rrec) in the PSCs, suggesting an effective defects passivation at the interface of mp-TiO2 and perovskite layers and a reduction in the trap-assisted recombination, which is consistent with the PL results. Our method recorded a champion PCE of 19.03% for PSCs, higher than a PCE of 14.91% obtained for control PSCs. Notably, the 8-Oxin improved the wettability of mp-TiO2 and affected perovskite grain growth, leading to a more compact and smooth perovskite layer. The 8-Oxin material improved the humidity resistance of PSCs due to diminished surface' paths for the reaction with humidity and suppressed surplus PbI2 in the corresponding perovskite layer.