基于电荷传输层优化的量子点发光二极管

Quantum dot light emitting diodes (QLED) with the structure of ITO/PEDOT:PSS/Hole transport material/quantum dot/ZnO nanoparticles/Al were fabricated by spin coating and electrode vacuum evaporation. Firstly, different effects on the performance of QLED devices of dispersant of ZnO nanoparticles were compared. When ZnO nanoparticles were dispersed in ethanol with ethanolamine, they made less damage to quantum dot layer and lead to high performance, thus the luminance of QLED and the current efficiency can be up to 22 940 cd/m² and 28.9 cd/A, respectively. Then the influence of different ratios of 4,4'-cyclohexylidenebis[N,N-bis(4-methylphenyl)aniline] (TAPC) in the poly(9-vinylcarbazole) (PVK) was investigated. High charge mobility of TAPC materials can enhance hole transportation, thus improve the balance of hole and electron recombination. When PVK:TAPC=3:1, the morphology of hole transport layer is relatively smooth, and the device can get a higher luminance. When PVK:TAPC=1:1, QLED gets the minimum turn-on voltage. The reasons of charge transport layer optimization is analyzed by comparing the surface morphology and the electrical and optical properties of the devices.