Highly Bright and Efficient Flexible Quantum Dot Light-Emitting Diodes on Metal-Coated PEN Substrate

Abstract

Quantum-dot (QD) based light-emitting diodes (QLEDs) have attracted significant attention in state-of-the-art wearable displays owing to the high form factor of QDs with excellent optical/electrical properties. These advantageous properties have led to notable advancements in QLEDs technology, making them flexible, lightweight, and compatible with human skin, which meets the requirements of wearable applications. To make the QLEDs wearable, however, alleviating the heat generated under high current is an urgent challenge. In this study, we present a flexible and bright top-emissive QLED fabricated on a plastic substrate with a thin (200 nm) heat dissipation layer. To preserve QLED performance even under sweaty conditions, we employed double layers of Parylene C/SU-8 for substrate planarization and device encapsulation. Furthermore, compared with typical wearable substrates that can hardly dissipate heat, the Al-metal induced flexible substrate can effectively dissipate the generated heat even under high current densities (2.3 A/cm2), exhibiting a high luminance (∼366,000 cd/m2) and a current efficiency (43.3 cd/A), respectively. The delicate device design of flexible QLEDs is anticipated to contribute to the advancement of next-generation wearable optoelectronics.