Inverted Red Quantum Dot Light-Emitting Diodes with a Dual-Layer ZnO Electron Transport Layer

Abstract

A dual-layer ZnO electron transport layer (ETL) was developed to improve the performance and stability of inverted red quantum dot light-emitting diodes (QLEDs). The design strategically combines a surface-modified ZnO layer at the indium tin oxide (ITO) interface to improve electron injection and an untreated ZnO layer adjacent to the quantum dot (QD) emissive layer to optimize energy level alignment. This dual-layer configuration exhibited a peak external quantum efficiency (EQE) of 20.7% and a luminance 1.59 times higher than that of the single-layer untreated device, while maintaining a comparable turn-on voltage to the treated ZnO device. The dual-layer design also demonstrated enhanced charge dynamics and extended operational stability, attributed to optimized energy level alignment. These findings highlight the effectiveness of dual-layer ZnO ETLs in advancing the efficiency and durability of QLEDs and provide valuable insights for next-generation emissive device development.