Insight into the Importance of Charge Transfer Dynamics in CsPbBr₃ Perovskite Nanocrystals for Photovoltaic Applications

Abstract

Charge transfer (CT) kinetics at the interfaces of lead-halide-based perovskite nanocrystals (PNCs) are pivotal in dictating the efficacies of energy conversion. Our investigation delves into the intricacies of CT between cesium lead bromide (CsPbBr 3 )-based PNCs and fullerene (C 60 ) employing a suite of spectroscopic and theoretical investigations. Notably, we discern a facile interfacial photoinduced electron transfer (ET) from CsPbBr 3 PNCs to C 60 , in good agreement with their respective aligned energy levels. Complementary current sensing atomic force microscopy measurements unveil a substantial enhancement in conductivity across the electrode−PNC−electrode nanojunction in the presence of C 60 . To establish the implications of such ET in photovoltaic devices, we have simulated the performance of two devices: one without C 60 and one with C 60 . We unfold an impressive increment in the power conversion efficiency from 12.5% to 15.8% in FTO/CsPbBr 3 /PEDOT:PSS/Au configurations upon integrating a band-aligned C 60 layer. These outcomes accentuate the relevance of regulated interlayer CT in optimizing photovoltaic device performance.