Pyridine-Based Multifunctional Surface Passivators Enable Efficient and Stable Perovskite Indoor Photovoltaics

Efficient surface passivation is crucial for mitigating defect-induced recombination losses in perovskite-based indoor photovoltaics (IPVs), where charge carrier dynamics are particularly sensitive to trap states under low-intensity illumination. Here, we introduce two pyridine-based passivators, tris[4-(pyridin-4-yl)phenyl]amine (TPAP) and its ionic counterpart (TPAP1), to achieve high-performance and stable perovskite IPVs. These passivators strongly coordinate with under-coordinated Pb²⁺ ions, effectively reducing trap densities and improving hydrophobicity. When incorporated into lead-based triple-cation CsFAMA perovskite films, TPAP and TPAP1 significantly suppress nonradiative recombination, leading to notable improvements in device performance. Remarkably, TPAP1 demonstrates a unique ability to simultaneously passivate multiple defect types, further optimizing charge transport and boosting the open-circuit voltage (V_OC). As a result, IPV devices incorporating TPAP and TPAP1 achieved remarkable indoor power conversion efficiencies of 30.1% and 31.7%, with V_OC values of 0.97 and 1.00 V, respectively, under 1000 lux white LED illumination. This study presents a scalable and effective strategy for defect passivation in perovskite IPVs, highlighting the critical role of multifunctional organic passivators in advancing next-generation energy harvesting technologies.