Highly Efficient White Light-Emitting Diodes Based on Quantum Dots and Polymer Interface

We proposed a novel white-light-emitting diode (LED) using the hybridization of quantum dots (QDs) blended with poly(9, 9-dioctylfluorenyl-2, 7-diyl) (PFO) as the white emissive layer and poly(N-vinylcarbazole) (PVK) blended with poly(N, N´ -bis (4-butylphenyl)-N, N´-bis(phenyl) benzidine (poly-TPD) as the hole transport layer (HTL). The red- and green-colored QDs with CdSe and ZnS core and shell structure were mixed with blue emissive PFO to form a hybrid emissive layer, and this layer generated pure white light. We analyzed the performance characteristics of the white-LED and the function of the HTL comprising poly-TPD doped with PVK; the use of this blend led to increased efficiency of the device via the creation of one more assisting energy step in the HTL. Consequently, our white-LED exhibited a luminance of 1,163 cd/m² and an efficiency of 1.01 cd/A at a CIE 1931 chromaticity of (0.33, 0.36).