Solution-Processed White Light-Emitting Diode Utilizing Hybrid Polymer and Red-Green-Blue Quantum Dots

Abstract

A hybrid polymer-quantum dots (QDs) white light-emitting diode (WLEDs) device with a multi-layer structure by all solution processing is simply fabricated by using a spin coating technique. From transmission electron microscopy (TEM) study, red-green-blue (RGB) CdSe/ZnS QDs are mainly distributed along with the circumference of poly(N-vinylcarbazole) (PVK) surfaces, resulting in core-shell hybrid polymer-QDs of [RGB CdSe/ZnS QDs]/PVK. The Al/Cs2CO3/[RGB CdSe/ZnS QDs+PVK]/poly[(N, N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine)] (poly-TPD)/poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT: PSS)/indium-tin-oxide (ITO)/glass WLEDs shows electroluminescence (EL) centered at around 474, 544, and 629nm with CIE coordinates, (0.44; 0.32) at the forward bias +11 V, which clearly reveals that CdSe/ZnS QDs existing at the interface between PVK plays as a recombination center of exciton. (C) 2012 The Japan Society of Applied Physics