Three birds with one stone: dual-interfaces and bulk co-passivation enable >21% efficiency of CsPbI3 solar cells with VOC of 1.27 V
Inorganic perovskite solar cells (IPSCs) have attracted significant attention due to their excellent light and thermal stability and potential in tandem applications. However, their efficiency and stability are often limited by residual lattice stress and defects at interfaces and within the bulk, causing severe nonradiative recombination. Here, we introduce a zero-dimensional supramolecular complex, (ETP)2SbCl5, as a dual-interface and bulk modifier to regulate CsPbI3 film growth. The modifier exhibits spatial segregation: ETP+ cations anchor at the buried interface, passivating defects on TiO2 and perovskite surfaces; Sb3+ and Cl− ions diffuse into the bulk during annealing, relieving residual stress; and Cl− accumulates on the top surface, passivating cation defects. Consequently, the modified CsPbI3 solar cell achieves a power conversion efficiency (PCE) of 21.71% and an open-circuit voltage (VOC) of 1.27 V, retaining 97.4% of initial efficiency after 500 h of maximum power point (MPP) tracking. This work demonstrates a synergistic strategy to simultaneously address interfacial and bulk defects, advancing high-performance and stable inorganic photovoltaics.