Photolithographic fabrication of high-resolution Micro-QLEDs towards color-conversion microdisplay

Microdisplay panels are critical components for metaverse technology. Aiming to achieve high-resolution and full-color microdisplay, we report the photolithographic fabrication of color-converted Micro-quantum dot light emitting diodes (QLED) panel by combining blue Micro-QLED electroluminescence (EL) device and red-green quantum dot color converter (QDCC). Pre-patterned templates were firstly photolithographically fabricated and then applied as substrate to fabricate patterned blue Micro-QLED device, achieving an ultra-high pixel resolution up to 6350 pixels per inch (pixel size ranging from 20 μm × 20 μm to 2 μm × 2 μm). Notably, the patterned blue devices achieve a peak external quantum efficiency (EQE) of 7.8% and a maximum brightness of 39,472 cd m^-2. The patterned red devices achieve a peak EQE of 18% and a maximum brightness of 103,022 cd m^-2. By integrating a dual-color red and green QDCC arrays on the top of the blue Micro-QLED, a prototype full-color Micro-QLED panel was fabricated, achieving a resolution up to 1184 pixels per inch with a peak EQE 4.8%, and a maximum brightness of 10 065 cd m^-2. The photolithographic fabrication of color-converted Micro-QLED provides an easy-operated method for achieving cost-effective microdisplay panels.