Redox-tunable structural colour images based on UV-patterned conducting polymers

TL;DR

This paper introduces a simple, scalable method to produce and dynamically tune vivid structural colours on conducting polymer films using UV patterning and electrochemical control, suitable for smart display applications.

Contribution

It presents a novel UV-patterned conducting polymer approach for creating high-resolution, tunable structural colours with easy fabrication and large colour gamut.

Findings

Controllable colour variation from violet to red via UV dose.

High-resolution colour images achieved with single UV exposure.

Dynamic colour tuning demonstrated through electrochemical modulation.

Abstract

Precise manipulation of light-matter interaction has enabled a wide variety of approaches to create bright and vivid structural colours. Techniques utilizing photonic crystals, Fabry-P\'erot cavities, plasmonics, or high-refractive index dielectric metasurfaces have been studied for applications ranging from optical coatings to reflective displays. However, complicated fabrication procedures for sub-wavelength nanostructures, limited active areas, and inherent absence of tunability with these approaches significantly impede their further developments towards flexible, large-scale, and switchable devices compatible with facile and cost-effective production. Herein, we present a way to generate structural colours based on conducting polymer thin films prepared on metallic surfaces via vapour phase polymerization and ultraviolet (UV) light patterning. Varying the UV dose leads to synergistic variation of film absorption and thickness, which generates controllable colours from violet to red. Together with greyscale photomasks this enables fabrication of high-resolution colour images using single exposure steps. We further demonstrate spatiotemporal tuning of the structurally coloured surfaces and images via electrochemical modulation of the polymer redox state. The simple structure, facile fabrication, wide colour gamut, and dynamic colour tuning make this concept competitive for future multi-functional and smart displays.