Yutongyang Fu, Le Liu, Zhibin Yu, Yilin Chang, Tonggang Jiu
Perovskite solar cells, with rapidly rising power conversion efficiencies and compatibility with low-temperature solution processing, are regarded as core technologies for next-generation photovoltaics. However, conventional planar tin oxide (SnO2) electron transport layers suffer from inherent drawbacks, such as limited specific surface area, long carrier transport pathways, and energy-level misalignment, which severely constrain further improvements in device performance. Here, a novel physical-chemical synergistic strategy is applied to the optimization of charge carrier dynamics of the conventional planar SnO2. On the one hand, a mesoporous SnO2 (m-SnO2) electron transport layer is designed and fabricated, which enhances charge extraction by enlarging the specific surface area and optimizing energy-level alignment. On the other hand, thiophene graphdiyne (SGDY) is further applied to precise chemical passivation of its interfacial defects and suppresses nonradiative recombination losses, synergistically promoting efficient interfacial carrier transport. Consequently, the devices based on the m-SnO2/SGDY heterostructure as the electron transport layer delivered a champion power conversion efficiency of 25.09% and exhibited significantly improved long-term operational stability.