High-resolution and high-performance full-color electroluminescent quantum dot light-emitting diodes

The rapid development of near-eye display has put forward higher requirements for the resolution and image quality, while the performance of quantum dots (QDs) is virtually unlimited by pixel size, making them an ideal material for the next generation high-resolution display devices. However, there are still significant challenges in depositing multi-color pixels within the micron range and achieving high performance for the full-color quantum dot light emitting diodes (QLEDs). Herein, a combination of directional transfer printing and Langmuir-Blodgett (LB) technique was utilized to precisely transfer multi-color QDs arrays in the predetermined direction, and the full-color QDs arrays demonstrated fantastic morphology and uniform arrangement. As a result, the full-color QLEDs showed excellent performance with a resolution of 6350 pixels per inch (PPI), a luminance up to 62,947 cd/m 2 and a peak external quantum efficiency (EQE) of 10.03 %. In addition, pixel spacing layers were introduced to further suppress electrical crosstalk and unwanted light emission, and the redundant part of emissive layers enabled QDs to be embedded into pixel spacing layers readily. The resulting full-color QLEDs with independent pixels exhibited a same high resolution of 6350 PPI, with a luminance of 35,427 cd/m 2 and a peak EQE of 8.55 %. Our work represents the best performance of full-color QLEDs with both high efficiency and high resolution, which demonstrates great potential in the application of future near-eye displays.