Improved blue quantum dot light-emitting diodes via chlorine passivated ZnO nanoparticle layer* *Project supported by the National Key R&D Program of China (Grant Nos. 2016YFB0401702 and 2017YFE0120400), the National Natural Science Foundation of China (Grant Nos. 62005114, 62005115, and 61875082), Key-Area Research and Development Program of Guangdong Province, China (Grant Nos. 2019B010925001 and 2019B010924001), Guangdong University Key Laboratory for Advanced

Abstract

In blue quantum dot light emitting diodes (QLEDs), electron injection is insufficient, which would degrade device efficiency and stability. Herein, we employ chlorine passivated ZnO nanoparticles as electron transport layer to facilitate electron injection into QDs effectively. Moreover, it suppresses exciton quenching at the QD/ZnO interface by blocking charge transfer channel. As a result, the maximum external quantum efficiency of blue QLED was increased from 2.55% to 4.60%, and the operation lifetime of blue QLED was nearly 4 times longer than that of the control device. Our work indicates that election injection plays an important role in blue QLED efficiency and stability.