Carbon-Based Stable CsPbIBr₂ Solar Cells with Efficiency of over 10% from Bifunctional Quinoline Sulfate Modification

The mixed-halide CsPbIBr2 all-inorganic perovskite solar cells (PSCs) have attracted widespread attention in view of their excellent stability and suitable band gap. However, the inherent high traps in perovskite films lead to serious nonradiative recombination and limit their future development. In this study, a passivation strategy is proposed to prepare CsPbIBr2 PSC with high efficiency, excellent long-term stability, and low hysteresis, which uses the in situ formed PbSO4 protective layer and the passivation of undercoordinated Pb2+ defects by introducing quinoline sulfate (QS). Due to the effective passivation, the QS-passivated CsPbIBr2 film with a larger grain size exhibits a better humidity resistance compared with the control one. The champion power conversion efficiency (PCE) of the carbon-based PSC without a hole transporter reaches 10.41% with an open-circuit voltage (VOC) of 1.298 V. Especially, it can retain over 98% of the primeval PCE after nearly 1000 h of aging in the ambient atmosphere. Therefore, our work may promote the application of all-inorganic PSC in commercial development.