Tang, Y.; Lin, C.; Nian, Z.; Gries, T. W.; Kim, J. H.; Pedersen, K. R.; Yang, Y.-T.; Hill, S.; Sathyaseelan, V.; Wang, Y.; Yang, H.; Zhao, H.; Xu, W.; Liu, Z.-F.; Luo, X.; Li, Y.; Yuan, C.; Huang, L.; Zhu, C.; Graham, K. R.; Musiienko, A.; Savoie, B. M.; Dou, L.: Selective Bidentate Coordination Reconstructs Residual PbI2 to Homogenize Interfacial Energetics in Perovskite Solar Cells. Journal of the American Chemical Society 148 (2026)
10.1021/jacs.6c05316
Open Accesn Version
Abstract:
Spatially heterogeneous interfacial energetics, often originating from residual lead iodide (PbI2), represent a fundamental bottleneck to both the efficiency and operational stability of perovskite photovoltaics. Conventional PbI2 passivation strategies based on monodentate ligands or highly polar solvents either interact weakly with PbI2 or undesirably perturb the underlying three-dimensional perovskite lattice. Here, we report a diammonium bidentate strategy that selectively reconstructs residual PbI2 into corner-sharing PbI6 octahedra while preserving the bulk perovskite. Enabled by dual-site coordination, a newly designed thiophene-based bidentate ligand (MeXT) stabilizes PbI6 units during passivation and establishes spatially homogeneous interfacial energetics. Perovskite solar cells incorporating MeXT achieve 26.19% power conversion efficiency and retain over 80% of their initial efficiency after 1000 h of continuous 1-sun illumination at 75 °C. This dual-anchor coordination passivation strategy establishes a general design principle for selectively treating residual PbI2 and creating electronically coherent and operationally stable interfaces in perovskite photovoltaics.