Enhanced Charge Transfer of QDs/Polymer Hybrid LED by Interface Controlling

We propose a quantum dots (QDs)/poly(N-vinylcarbazole) (PVK) hybrid light-emitting diode (LED) to improve the electron and hole confinement in the QDs layer. QDs used as monochromatic emitters are dispersed in a PVK matrix with a wide bandgap for quantum wells. The HOMO and LUMO level of the PVK can act as a hole transport buffer and an electron-blocking buffer in the hybridized layer. We fabricate an LED using a simplified QDs/PVK hybrid emissive layer (EML) and compare its performance with that of the hybrid LED with controlled QDs concentration. From the result, it is found that the 1.0 wt% QDs within the PVK hybrid LED show the best performance among the compared LEDs, with a luminance of 5989 cd/m² and an efficiency of 4.2 cd/A. The efficient energy transfer and performance of the QDs/PVK hybrid EML are highly depended on the doping concentration of the QDs.