Effect of electric field on the photoluminescence of polymer-inorganic nanoparticles composites

TL;DR

This study investigates how applying an electric field influences the photoluminescence of a polymer-zinc oxide nanoparticle composite, revealing controllable emission properties and underlying recombination mechanisms.

Contribution

It demonstrates electric field modulation of photoluminescence and identifies multiple radiative recombination pathways in polymer-inorganic composites.

Findings

Electric field suppresses green-yellow emission

PL emission shifts towards blue under voltage bias

Non-linear current-voltage behavior observed

Abstract

We report on the effect of electric field on the photoluminescence, PL, from a composite consisting of a conjugated polymer mixed with zinc oxide nanoparticles. We have found that in the absence of electric field PL emission from the composite film has two maxima in the blue and green-yellow regions. Application of a voltage bias to planar gold electrodes suppresses the green-yellow emission and shifts the only PL emission maximum towards the blue region. Current-voltage characteristics of the polymer-nanoparticles composite exhibit the non-linear behavior typical of non-homogeneous polymer-inorganic structures. Generation of excited states in the composite structure implies the presence of several radiative recombination mechanisms including formation of polymer-nanoparticle complexes including exciplex states and charge transfer between the polymer and nanoparticle that can be controlled by an electric field.