Bright, Flexible, and Waterproof Top-Emitting InP Quantum Dot Light-Emitting Diodes on Al Foil

Quantum dot light-emitting diodes (QLEDs) with high form factor are attracting great attention owing to the superb optoelectrical properties of quantum dots (QDs) and their ubiquitous application, such as wearable displays. However, there have been significant challenges in increasing the brightness of flexible QLEDs due to the inferior thermal conductivity of conventional flexible substrates. In this work, we demonstrate bright, flexible, and waterproof top-emitting QLEDs based on InP/ZnSe/ZnS QDs, which are promising for human-interfaced wearable displays. We adopted an Al foil substrate with high thermal conductivity, which can quickly dissipate the Joule heat generated at high current densities, and a Parylene C/SU-8 bilayer thin-film on both sides of the QLEDs to ensure the surface planarization and to prevent moisture permeation. As a result, the flexible QLED works well even when bent or in contact with water with a maximum luminance of ∼40000 cd/m2. We believe that our device design strategies can contribute to the development of next-generation flexible optoelectronics.