以具三重態-三重態湮滅特性的雙蒽藍色發光體以及第三丁基咔唑主體材料製作有機發光二極體之研究

Abstract

本篇論文主題有二。其一為以雙蒽衍生物為發光體製作的三重態-三重態湮滅藍色螢光有機發光二極體，其二為以第三丁基咔唑衍生物為主體材料製作的藍色磷光有機發光二極體。 1-phenyl-2-(10-(4-(10-phenylanthracen-9-yl)phenyl)anthracen-9-yl)-1Hbenzo[d]imidazole (diAnBiz) 為一新型藍色螢光材料，其薄膜態的螢光量子產率高達89.8%。我們因此以diAnBiz 做為發光體製作無摻雜元件以及使用不同主體材料製作摻雜元件， 並以9,9’-(2-(1-phenyl-1H-benzo[d]imidazol-2-yl)-1,3-phenylene)bis(9H-carbazole) (o-DiCbzBz)做為主體材料並摻雜13% diAnBiz 的元件達到最佳效率表現，其於電流效率、功率效率及外部量子效率分別為 6.6 cd/A, 5.9 lm/W and 8.3%。我們也從暫態電致放光觀察到此元件的三重態-三重態湮滅特性。 我們以五種具有高三重態能階的3,6-di-tert-butyl carbazole 衍生物為主體材料並以bis[(4,6-difluorophenyl)pyridinato-N,C2](picolinato)iridium(III) (FIrpic)為摻雜物製作藍色磷光有機發光二極體，其中以具有相近的電子電洞遷移率的 3,6-di-tertbutyl-9-(2-(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl)-9H-carbazole (SM66) 為主體材料所製作的元件展現出最佳效率。經由調變摻雜濃度、電子傳輸層與發光層厚度後，以SM66 為主體材料的效率優化元件在電流效率、功率效率及外部量子效率分別達到57.40 cd/A、51.52 lm/W 和28.77%。

There are two topics in this thesis. The first one is triplet-triplet annihilation (TTA) blue fluorescent organic light-emitting diodes (FOLEDs) using a bisanthracene derivative as the emitter. The second one is blue phosphorescent OLEDs (PhOLEDs) using tert-butyl substituted carbazole derivatives as the host materials. A novel blue emitter, 1-phenyl-2-(10-(4-(10-phenylanthracen-9-yl)phenyl)anthracen-9-yl)-1H-benzo[d]imidazole (diAnBiz) exhibited high photoluminescence quantum yield of 89.8% in thin-film state. We employed it as the blue fluorescent emitter by fabricating non-doped OLEDs and doped OLEDs with different host materials. An optimized device using 9,9’-(2-(1-phenyl-1H-benzo[d]imidazol-2-yl)-1,3-phenylene)bis(9H-carbazole) (o-DiCbzBz) as the host doped with 13% diAnBiz achieved 6.6 cd/A, 5.9 lm/W and 8.3% for current efficiency, power efficiency and external quantum efficiency (EQE), respectively. The TTA characteristics of the device was also obtained by transient electroluminescence measurements. In the second half of this thesis, we employed five 3,6-di-tert-butyl carbazole derivatives which have high triplet energy levels as host materials of blue PhOLEDs doped with a blue phosphorescent dopant, bis[(4,6-difluorophenyl)pyridinato-N,C2](picolinato)iridium(III) (FIrpic). Among the five host materials, device using 3,6-di-tert-butyl-9-(2-(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl)-9H-carbazole (SM66) as the host exhibited highest efficiencies due to the balanced electron-hole mobility of SM66. By tuning dopant concentration, thickness of electron-transporting layer and emitting layer, the optimized device with SM66 host achieved 57.40 cd/A, 51.52 lm/W and 28.77% for current efficiency, power efficiency and EQE, respectively.