Highly Enhanced Light Recycling in Quantum Dot Displays by Sidewall Reflectors

Quantum dot (QD) color conversion-based displays have emerged as one of the most promising next-generation devices due to their superior emission properties in terms of color expression. To date, however, existing QD color conversion layer (QD-CCL) technologies have suffered from low luminance and power efficiency, mainly due to significant light absorption by the bank structure. Here, the color conversion efficiency of QD-CCL has been significantly enhanced by fabricating a highly reflective metal layer on the side surface of the bank structure. Using a high-aspect-ratio silver reflector fabricated through a secondary sputtering lithographic technique involving argon ion bombardment, the fabricated QD-CCL is combined with a blue organic light-emitting diode (OLED) serving as a light source. As a result, light recycling from the reflector significantly enhances color conversion efficiency and luminance by up to 4.60-fold and 4.29-fold, respectively. Optical simulation reveals that higher pixel resolution provides greater reflection probabilities during extraction. This photomask-free approach is not only simple but also highly compatible with existing semiconductor fabrication processes, making it a viable commercial alternative for all color-converting structures that utilize light-emitting materials with omnidirectional emission characteristics.