Minimizing Photovoltage Loss for Efficient p-i-n Perovskite Solar Cells via a Dual-Site Anchoring Bridge.

Perovskite solar cells (PSCs) suffer from severe nonradiative recombination-induced photovoltage loss, limiting the device overall performance. To address this key issue, an efficient strategy via a dual-site anchoring bridge is developed to engineer the heterointerface between perovskite and PCBM electron transport layer. The resulting reinforced and homogeneous passivation by forming strong dual-site P─O─Pb covalent bonds, effectively decreases perovskite surface defect density. This simultaneously reconstructs surface energetics of perovskite with upshifted Fermi level and enhanced electric field, promoting electron extraction at the perovskite/PCBM heterointerface. Corresponding nonradiative recombination at such perovskite electron-selective contact is greatly suppressed. An impressive power conversion efficiency of 26.3% is obtained with excellent stability under continuous maximum power point operation, and a supreme photovoltage of 1.215 V in p-i-n PSCs via interfacial engineering reported so far. This work offers a promising strategy for solving the perovskite contact challenge via innovative modifier for further improvement of PSCs.