Enhancement and tuning of the defect-induced electroluminescence of ZnO mesoporous layers in the visible range

TL;DR

This paper presents a method to enhance and tune the visible electroluminescence of mesoporous ZnO layers by patterning metallic patches, enabling color control and polarization effects in LEDs.

Contribution

It introduces a novel patterning technique using metallic patches to locally modify ZnO morphology, significantly improving electroluminescence and enabling color and polarization tuning.

Findings

Enhanced electroluminescence in ZnO layers through metallic patterning

Ability to tune emission color by adjusting electrode thickness

Sub-micron metallic patterns induce plasmonic effects for additional control

Abstract

We show a way to pattern the visible electroluminescence of solution-processed mesoporous ZnO layers. Our approach consists in locally changing the nanoscale morphology of the coated ZnO layers by patterning the underlying surface with thin metallic patches. Above the metal, the ZnO film is organized in clusters that enhance its defect-induced electroluminescence. The resulting emission occurs over a large continuum of wavelengths in the visible and near-infrared range. This broad emission continuum is filtered by thin film interferences that develop within the device, making it possible to fabricate LEDs with different colours by adjusting the thickness of their transparent electrode. When the metallic patterns used to change the morphology of the ZnO layer reach sub-micron dimensions, additional plasmonic effects arise, providing extra degrees of freedom to tune the colour and polarization of the emitted photons.