Polymer hybrid white quantum dots light-emitting diodes with a nanostructured electron injection layer.

Abstract

In this study, poly(N-vinylcarbazole) (PVK) polymer was blended with various dimensional CdSe/ZnS core-shell quantum dots to be used as a single emissive layer of white quantum dots light-emitting diodes (WQLEDs). Besides, the nanostructured ITO/ZnO nanorod array was used as electron transport/injection layer to shorten carrier transport distance, accelerate carrier transport velocity, and enhance carrier transport surface area. Consequently, luminance and luminous efficiency were increased by the resulting increase of the carrier injection current density and the hole-electron recombination opportunity. The CIE of (0.329, 0.331) was obtained for the WQLEDs by using the weight ratio of 1.5:1.3:2.2 of the red, green, and blue (RGB) quantum dots. Compared with the WQLEDs without the nanorod array, the WQLEDs with the 1.5-µm-periodic ITO/ZnO nanorod array obtained an increased luminance of 16333 cd/m2 (compared with 7191 cd/m2) and an increased luminous efficiency of 3.13 cd/A (compared with 2.30 cd/A).