All Inkjet-Printed red Micro Quantum-Dots Light-Emitting diodes (QLEDs): Fabrication and performance

Micro quantum-dots light-emitting diodes (Micro-QLEDs) is a pivotal evolution in QLEDs displays. Inheriting the advantages of conventional QLEDs, such as wide color gamut, narrow emission bandwidth, and self-emissive properties while achieving ultra-small size. However, current fabrication methods for Micro-QLEDs are limited by complex processing, efficiency degradation, and high manufacturing costs, which hinder their commercialization. In this study, we employ an all inkjet-printing (AIJP) approach to overcome the compatibility limitations of conventional inkjet processes. In particular, A self-emissive red Micro-QLEDs with the structure ITO/PEDOT:PSS/TFB/QD/ZnO/Ag by stacking 5-soluble layers without intermixing. Its size has been scaled down to 30 μm—the smallest light-emitting area QLEDs for AIJP reported to date. The red Micro-QLEDs achieves the maximum external quantum efficiency (EQE) of 7.35% and a current efficiency of 11.19 Cd/A and the highest brightness of 61,377.41 Cd/m 2 . Accurate printing and uniform film formation were realized through systematic ink formulation optimization. The AIJP process offers significant advantages, including simplified fabrication, high material utilization, and independence from photolithography. This work represents a critical step toward the industrial production of full-color Micro-QLEDs displays and demonstrates strong potential for applications.