Customizing Tactile and Visual Perceptions of Organic Light–Emitting Diodes by Surface Coatings

Abstract

Organic light‐emitting diodes (OLEDs) offer novel and unique possibilities for illumination. The realization of transparent and flexible devices facilitates integration in everyday objects such as windows, clothing, or packaging labels, while posing new challenges to product engineering. Innovative OLED light sources, fulfilling multiple purposes additional to lighting, are likely to be touched and consciously observed far more frequently than conventional illuminants. Herein, a polymer coating used to customize tactile and visual perceptions of OLED substrate surfaces is demonstrated. Tetrapodal zinc oxide particles and color pigments are incorporated in a poly(methyl methacrylate) matrix to modify surface roughness and color impression of the coating. Variation of the particle content and composition yields different combinations of roughness characteristics, thus altering tactile surface perception and light scattering. Utilization of color pigments exhibiting low transmission dispersion allows for changes of the coating color while maintaining the original OLED emission color. The presented coating concept is expected to be a promising approach to adjust haptic and optical device properties to specific application requirements while maintaining spectral OLED emission characteristics.