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

• Main Authors: Nai-ChyiChang, 張乃琪
• Other Authors: Sheng-Yuan Chu
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/j9ra5q

碩士 === 國立成功大學 === 電機工程學系 === 107 === 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 Å/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.