Ionic environment control of visible photo-luminescence from ZnO nanoparticles

TL;DR

This study demonstrates that the visible photoluminescence of ZnO nanoparticles can be modulated by the ionic environment, with electrolytes capable of quenching emission through surface charge effects influencing band bending.

Contribution

It introduces a novel method to control ZnO nanoparticle luminescence via ionic environment manipulation, linking surface charge to emission properties.

Findings

Electrolytes can quench ZnO photoluminescence.

Surface charge affects band bending and emission.

Correlation established between zeta potential and emission.

Abstract

We report a novel effect that the visible photoluminescence (in the blue-green band) from ZnO anoparticles can be controlled by changing the ionic or polar nature of the medium in which the nanoparticles are dispersed. We find that the presence of sufficient amount of electrolytes can even quench the emission. We propose an explanation based on surface charge of the ZnO nanoparticles which control the band bending in the depletion layer at the surface of the anoparticles. The band bending in turn, decides the predominant nature of the visible emission. The explanation is validated by establishing a direct correlation between the visible emission and the zeta potential.