Facilitating the Carrier Transport Kinetics at the CsPbBr₃/Carbon Interface through SbX₃ (X = Cl, Br, I) Passivation

The nonradiative carrier recombination at the perovskite/carrier selective layer (CSL) interface was accounted for the inferior power conversion efficiency (PCE) of perovskite solar cells (PSCs), especially rigid all-inorganic perovskite (CsPbI₃ and CsPbBr₃). In this study, targeting the poor interface, we introduce SbX₃ (X = Cl, Br, I) surface passivation at the CsPbBr₃/carbon interface. Smoothed compressive strain, reduced defect density, and enhanced energy-level alignment were achieved simultaneously, facilitating carrier extraction at the selective interface. With the simple aqueous solution-based two-step process, the PCE of our SbI₃ passivated carbon-based CsPbBr₃ PSCs has increased from 7.81% (without passivation) to 9.69%, a ∼25% enhancement. Specifically, V_oc (1.657 V) of the SbI₃-passivated cells was much higher than that of the control ones (1.488 V), confirming the ameliorated interface. Finally, our unencapsulated SbI₃ passivated devices maintain 90% of their initial PCEs while left in the air for 30 days with a relative humidity of 60%. To conclude, we present an interfacial carrier extraction-enhanced strategy for preparing high-performance and stable CsPbBr₃-based PSCs.