A universal strategy for defects and interface management enables highly efficient and stable inverted perovskite solar cells†

The surface post-treatment of perovskite films is regarded as one of the most effective methods for enhancing the performance of perovskite solar cells (PSCs) and is essential for achieving high-efficiency PSCs. However, a universal strategy for surface post-treatment that accommodates different A-site components and various bandgaps of perovskites has often been overlooked. In this study, we propose a universal strategy that simultaneously applies phenethylammonium bromide (PEABr) and 5-amino-1,3,4-thiadiazole-2-thiol (5ATT) to the top surface of perovskite films by a one-step spin-coating procedure. Both PEABr and 5ATT effectively passivate surface defects and improve interface contact. Additionally, 5ATT can infiltrate into the perovskite films longitudinally to passivate bulk defects, thereby achieving effective defects and interface management for reducing nonradiative recombination and extending carrier lifetimes. The optimized devices achieve a higher power conversion efficiency (PCE) of 24.85% (FAMACsRb) compared to the control device, which has a PCE of 21.47%. The stability of the best-performing device is also enhanced, maintaining 89% of its initial PCE after tracking at the maximum power point (MPP) for 600 hours. Furthermore, this strategy is reliably adaptable to the perovskites with different A-site components (MA, FACs, FAMACs) and various bandgaps (1.68, 1.77 and 1.82 eV), achieving a champion PCE of 25.88% (certified at 25.44%) based on the FAMACs PSC. The approach demonstrated in this work exhibits universal applicability across various perovskites, making it an attractive and promising method for the fabrication of single or tandem PSCs.