Electron-Induced Degradation in Blue Quantum-Dot Light-Emitting Diodes.

Abstract

The poor stability of blue quantum-dot (QD) light-emitting diodes (B-QLEDs) hinders their application in displays. To improve the stability of B-QLEDs, the degradation mechanism should be revealed. Here, the degradation mechanism of B-QLEDs is investigated by monitoring the changes occurring in the QDs and the hole transport layers (HTL) during device operation, respectively. It is revealed that the accumulation of electrons within the QDs is responsible for the degradation of the devices. On the one hand, the accumulated electrons induce the detachment of oleic acid ligands, leading to permanent damage to the stability of B-QDs. On the other hand, the accumulated electrons leak into the HTL or recombine at the HTL/QDs interface, leading to the degradation of HTL. The formation of surface defects in B-QDs and the decomposition of HTL contribute to the degradation of B-QLEDs. The results reveal the strong dependence of B-QLEDs stability on the accumulated electrons, the QDs and the HTL, which can help researchers to develop effective design strategies for improving the lifespan of B-QLEDs.