High-Efficiency, Large-Area, Flexible Top-Emitting Quantum-Dot Light-Emitting Diode
Hongwei Yu, Hao Zhu, Mengxin Xu, Jiaming Zhang, Haiwei Feng, Letian Zhang, Shihao Liu, Wenfa Xie
Abstract
Flexible displays are essential to provide information in real time for human–machine interactions. As a next-generation display technology, quantum-dot light-emitting diodes (QLEDs) are potentially serving as key components for flexible displays. However, it is still challenging for QLEDs to simultaneously achieve flexibility, large-scale production, and high efficiencies. To this end, a strategy is proposed here by combining a top-emitting structure, optical microcavity optimization, and large-scale film preparation. A top-emitting microcavity with semitransparent and reflective metals is designed to achieve flexibility, efficient carrier injection, and high light extraction efficiency. Precision manufacturing of large-area QLEDs with the designed top-emitting microcavity is achieved by combining surfactant-assisted blade-coating and vacuum thermal evaporation processes. With this strategy, a large-area flexible QLED with an active area of 400 mm2 and a maximum external quantum efficiency of 21.8% is developed. This strategy provides a promising approach toward the development of flexible displays with the demonstration of a 1.3 in. passive-matrix flexible QLED display of 19 by 19 pixels.