Efficient Quantum Dot Light-Emitting Diodes With DAA Doped Electron Transport Layer

Zinc oxide nanoparticles (ZnO NPs) is widely used as electron transport layer material in quantum dot light-emitting diodes (QLED) due to its high carrier mobility, unique photoelectric properties and good stability. However, because ZnO has higher electron mobility than organic hole transport materials, the carrier transport is unbalanced. In addition, ZnO NPs has many surface defects, which is easy to capture electrons or holes, increasing the probability of non-radiative recombination. To solve these problems, we carefully selected an organic compound diallylamine (DAA) doping method to modify the surface of ZnO. DAA is found to not only reduce the quenching at the interface between ZnO and QD, but also regulate the energy level position to promote the carrier injection balance of QLED devices. Compared with control ZnO QLED, the external quantum efficiency (EQE) of the red QLED with DAA-modified ZnO NPs is significantly improved, the peak EQE of the devices increased by 21 % from 18.8 % to 23.6 %. respectively. It is a simple and economical solution for manufacturing high-performance QLED.