Multi-Functional Electrophoretic Deposition for Crosstalk-Free, Ultra-High-Resolution Full-Color QLEDs

Abstract

Patterning of colloidal quantum dots (QDs) is essential for realizing high-resolution, high-brightness, full-color quantum dot light-emitting diodes (QLEDs) and QD color-conversion layers for near-eye microdisplays in augmented and virtual reality systems. However, the reliably producing uniform nanoscale QD patterns and practical full-color QLEDs remains a significant challenge. Here, we report a multi-functional electrophoretic deposition (MEPD) strategy that enables selective, sequential, and high-throughput patterning of nanoscale QD patterns. Using ligand-engineered, negatively charged QDs, MEPD forms 435 600 sub-pixels with only 3 V applied for 15 s. The same solution chemistry and low-voltage conditions enable multi-color patterns across feature sizes ranging from tens of micrometers down to 500 nm, demonstrating constant process complexity independent of pixel dimensions. Moreover, sequential MEPD of ZnO nanoparticles and QDs produces full-color QLEDs featuring a pixel-isolated electron transport layer, lateral currents in the tens of nanoamperes, and enhanced efficiencies. These results establish a scalable and manufacturing-compatible route toward next-generation ultra-high-resolution display.