The mechanism characteristics investigations and process optimization of high efficiency exciplex-based OLEDs

Abstract

In this thesis we investigated the mechanism and characteristics of exciplex-based OLEDs by using m-MTDATA and Bphen because of the similar lowest triplet excited states as hole and electron transport organic materials with different emission layer process evaporation rates We controlled emission layer process evaporation rates of OLED to make sure that two different electrical types of molecules were well-mixed After that we studied the improvement of carrier transport balance to make sure that carrier recombination region is accurately located in emission layer which helps to increase the use of excitons and improve OLED performance First part we obtained better OLED efficiency of 61 0 cd/A with minimum surface roughness and maximum capacitive-voltage when evaporation rate was 0 8 ?/s This value is increased by 4 1 times over the reported data Secondly we found that as using 22 nm hole transport layer and 30 nm electron transport layer we could get the most carrier balanced devices At the same time we obtained the best OLED efficiency of 71 5 cd/A in our study at a luminous intensity of 440 cd/m2

Date of Award	2019
Original language	English
Supervisor	Sheng-Yuan Chu (Supervisor)