Comprehensive experimental and theoretical study on the interaction between Ag nanoparticles and all-inorganic CsPb(Br,I)3 perovskite nanocrystals

Abstract

The energy conversion efficiency in halide perovskites remains limited by charge carrier generation, separation, mobility, and extraction. In this work, we investigate interfacial interactions governing exciton dynamics in all-inorganic CsPb(Br,I)3 nanocrystals coupled with Ag metallic nanoparticles (AgNPs). Our findings reveal strong photoluminescence (PL) quenching when AgNPs are deposited on the surface of CsPb(Br,I)3 nanocrystals, indicating the charge transfer process. A comprehensive theoretical analysis suggests that the interaction between CsX-terminated quantum dots (QDs) and AgNPs is primarily governed by weak physical adsorption van der Waals (vdW) forces, which is in contrast to PbX2 terminations, where the QD/NP interface is mediated by a combination of vdW forces and stronger chemical interactions. Our electronic structure calculations confirm the feasibility of carrier separation and the emergence of two concurrent charging processes at the QD/NP interfaces. The final charge separation configuration of QD[h]/NP[e], meaning that holes are localized in the QDs and the electrons at the nanoparticles, is more likely to occur than QD[e]/NP[h]. We discuss the electron–hole creation and separation mechanisms at the heterostructure interface, highlighting how enhanced interfacial interactions improve electronic coupling, influence optical response, and modify charge carrier dynamics. Understanding these interfacial mechanisms is essential for optimizing perovskite-based nanostructures in optoelectronics applications.