Design and Synthesis of meta-Terphenyloxadiazole Derivatives as Electron Transporting Materials for Phosphorescent Organic Light-Emitting Diodes

• Main Authors: Shih, Cheng-Hung, 施承宏
• Other Authors: 鄭建鴻
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/30218048199825124865

碩士 === 國立清華大學 === 化學系 === 101 === In the literature, m-terphenyl-modified materials have shown high triplet energy gap and thermal stability while utilizing oxadiazole-based materials as electron-transporting materials. Therefore, in this thesis, we developed five electron transport materials: PhOXD, FOXD, 3PyOXD, 4PyOXD and TPOTP by introduction of m-terphenyl and oxadiazole moieties. The LUMO levels of these materials relied on the linkage of oxadiazole moieties; as a result, we could adjust the LUMO levels of these materials by modifying the functional groups on oxadiazole moieties. In addition, the triplet energy gaps were determined to be 2.62-2.88 eV and they also showed good thermal stability which could be suitable for various phosphors in PhOLEDs. In order to assess the electron transport properties, the electron-only devices were fabricated with these materials and commercial available materials: OXD-7, TAZ, Balq and BCP/Alq3. As expexted, our ETMs exhibit the better electron mobility than commericals. In red PhOLED, the best device using CzPPQ as a host and 3PyOXD as an ETM shows a maximum EQE of 26.6% and a maximum CE of 33.5 cd/A with CIE coordinates of (0.67, 0.33). In green PhOLED, the best device using BCPO as a host and PhOXD as an ETM exhibits a maximum EQE of 26.3%, a maximum CE of 101.7 cd/A with CIE coordinates of (0.29, 0.64). In blue PhOLED, the best device using BCPO as a host and PhOXD as an ETM exhibits a maximum EQE of 26.4%, a maximum CE of 55.0 cd/A with CIE coordinates of (0.14, 0.32).