Leveraging Plasmonic Hot Electrons to Quench Defect Emission in Metal -- Semiconductor Nanostructured Hybrids: Experiment and Modeling

TL;DR

This study investigates how plasmonic gold nanoparticles influence defect-related and near band edge photoluminescence in ZnO nanorods, revealing hot carrier dynamics that can modulate emission properties in hybrid systems.

Contribution

It combines experimental and modeling approaches to demonstrate hot carrier transfer effects in Au-ZnO nanostructures, advancing understanding of light-matter interactions in hybrid plasmonic materials.

Findings

Gold nanoparticles quench defect-related visible PL in ZnO nanorods.

Hot carriers generated by Au NPs modify ZnO's luminescence and defect states.

Interfacial band bending facilitates charge transfer under illumination.

Abstract

Modeling light-matter interaction in hybrid plasmonic materials is vital to their widening relevance from optoelectronics to photocatalysis. Here, we explore photoluminescence from ZnO nanorods (ZNR) embedded with gold nanoparticles (Au NPs). A progressive increase in Au NP concentration introduces significant structural disorder and defects in the ZNRs, which paradoxically quenches defect related visible photoluminescence (PL) while intensifying the near band edge (NBE) emission. Under UV excitation, the simulated semi-classical model realizes PL from ZnO with sub-band gap defect states, eliciting visible emissions that are absorbed by Au NPs to generate a non-equilibrium hot carrier distribution. The photo-stimulated hot carriers, transferred to ZnO, substantially modify its steady-state luminescence, reducing NBE emission lifetime and altering the abundance of ionized defect states, finally reducing visible emission. The simulations show that the change in the interfacial band bending at the Au-ZnO interface under optical illumination facilitates charge transfer between the components. This work provides a general foundation to observe and model the hot carrier dynamics in hybrid plasmonic systems.