Sol-gel processed tungsten trioxide nanocrystals layer for efficient hole-injection in quantum dot light-emitting diodes

ABSTRACT In this work, we report highly bright and efficient quantum dot light-emitting diodes (QLEDs) using tungsten trioxide (WO3) nanocrystals (NCs) thin film as hole-injection layers (HIL). The WO3 thin film is prepared by a simple sol-gel method using W powder and H2O2 as precursors, stirring vigorously at room temperature, followed by calcinations at 420 °C for 1 h. The WO3 thin film is compact and smooth, enabling the formation of HIL in green QLED. The luminance, current efficiency and operational lifetime of the QLED is 18560 cd m−2, 11.8 cd A−1 and 11844 h, respectively.