Immobilizing Lead and Healing Surface Defects via Perfluorinated Tertiary Amine Molecules Enables High-Performance Sustainable Inverted Perovskite Solar Cells.

The intrinsic instability and nonradiative recombination induced by surface defects hinder the further development of p-i-n inverted perovskite solar cells (PSCs). Simultaneously, the commercial application of inverted PSCs is limited by environmental unfriendliness resulting from lead leakage. Herein, a universal perfluorination strategy is reported to immobilize lead and passivate surface defects of perovskite films in inverted PSCs. It is demonstrated that perfluorinated perfluorotriethylamine (PFTEA) can form PFTEA·PbI complex with PbI via a strong coordination bond, which is favorable for suppressing lead leakage and promoting defect passivation. Due to much reduced surface nonradiative recombination, the PFTEA-modulated inverted PSCs deliver a fascinating certified stabilized power conversion efficiency (PCE) of 26.65%, a record efficiency value reported for PSCs using the vacuum flash evaporation technique. Moreover, the PFTEA-modulated devices maintain 92% of their initial PCE after 1000 h of continuous maximum power point tracking. This work provides a simple and effective avenue to advance the sustainable development of inverted photovoltaic technology through a perfluorination strategy.