Organic Electroplated Luminescent Microarrays up to 2800 ppi toward Near-Eye Displays via Diffusion-Weakened Boundary Effects

The quality of high-resolution luminescent films is key for high-definition and near-eye displays, but is limited by the apparent boundary effects at sub-micrometer scales, such as boundary quenching in inorganic light-emitting diodes and the coffee ring effect in inkjet printing. This study demonstrates that the electroplating of electrified electrode microarrays is not limited by boundary effects, enabling the deposition of luminescent dyes as high-quality films with uniform and smooth morphologies as well as strong electroluminescence. As radial diffusion is the key to boundary effect in electroplating technology, small pixels tend to weaken the boundary effects and ease the overlap of diffusion layers. When the pixel size is lower than the critical value, the boundary effects can be eliminated. The smallest pixel width attempted is 3 mu m, and prototype devices of monochrome and red-green-blue-colored pixel arrays are successfully fabricated on glass and flexible backplanes without bad pixels and lines, indicating the high potential of the electroplating technique to achieve high-resolution and immersive virtual reality for fine displays.