Simulation of a new architecture of organic white-light-emitting diode by quantum dot and photonic crystal to improve efficiency

Abstract

A novel inverted hybrid quantum dot/organic light-emitting diode (IH-QDOLED) with a transparent conducting oxide photonic crystal structure is proposed in this study. Such improved electrical and optical characteristics as luminescence efficiency, extraction efficiency, external quantum efficiency, carrier injection, size-tunable color of QDs, and solution-processable fabrication make IH-QDOLEDs a good candidate with which to achieve high-performance and low-cost LED (light-emitting diode) devices. These efficient LEDs consist of three rows of CdSe quantum dots with different sizes blended in TPBi. In order to optimize the IH-QDOLED structure, we have performed a simulation based on the finite difference time domain (FDTD) method. Also, the characteristics of this novel structure have been compared with those of a conventional structure. As it is found, the maximum external quantum efficiency (EQE) is increased from 30 % to 50 %, and the turn-on voltage has risen from 4.5 V to 5.5 V, compared to the conventional structure. Our results show that the angular distribution of the radiant power is uniform over a wider range of view angles, which can be attributed to the interaction of guided modes with an embedded photonic crystal structure.