以咔唑及咪唑衍生物作為藍色磷光有機發光二極體主體材料之研究

Abstract

本篇論文研究的主題，利用咪唑基團 (Imidazole) 和咔唑基團 (Carbazole) 搭配的衍生物做為主體材料，前者咪唑基團為一個具有較佳的電子傳輸特性，後者咔唑基團則具有較佳的電洞傳輸特性，將兩者結合成為新的雙極性主體材料，9,9',9'-(2-(1-phenyl-1H-benzo[d]imidazol-2-yl)benzene-1,3,5-triyl)tris(9H-carbazole) (o-3CbzBz)，以摻雜藍色磷光客體材料 Bis[2-(4,6-difluorophenyl)pyridinato-C2,N](picolinato)iridium(III) (FIrpic) 來製作藍光磷光有機發光二極體。利用 o-3CbzBz 做為發光層主體材料，搭配 Diphenylbis(4-(pyridin-3-yl)phenyl)silane (DPPS) 為電子傳輸層，最高電流效率達到 57.63 cd/A、功率效率為 56.61 lm/W與外部量子效率為 27.96%。為了達到更高的效率，將 o-3CbzBz 元件最優化架構摻雜 2,2'-bis(1-phenyl-1H-benzo[d]imidazol-2-yl)biphenyl (BImBP)，來達至載子平衡，在更佳的復合位置放光、從提高亮度和效率，其最高電流效率為 62.56 cd/A、功率效率為 61.52 lm/W與外部量子效率為 30.38%，元件壽命提升2倍。另外，希望得到更好的元件壽命，所以改用電子遷移率更高的 1,3,5-Tri(m-pyridin-3-ylphenyl)benzene (TmPyPB)。在這個系統下最高電流效率為 56.20 cd/A、功率效率為 55.55 lm/W與 26.85%，而壽命提升約4倍。

In this thesis, we fabricated the blue phosphorescent organic light-emitting diodes (PhOLEDs) with bipolar carbazole- imidazole derivative host material, 9,9',9'-(2-(1-phenyl-1H-benzo[d]imidazol-2-yl)benzene-1,3,5-triyl)tris(9H-carbazole) (o-3CbzBz) as host and iridium(III)bis[(4,6-difluorophenyl)-pyridinato-N,C2’]picolinate (FIrpic) as guest. We achieved a maximum current efficiency of 57.63 cd/A, power efficiency of 56.61 lm/W, and external quantum efficiency of 27.96% in the blue PhOLED with o-3CbzBz as host material. Then, we achieved a maximum current efficiency of 62.56 cd/A, power efficiency of 61.52 lm/W, external quantum efficiency of 30.38%, and 2-times increase in operation lifetime with the mixing layer of o-3CbzBz and 2,2'-bis(1-phenyl-1H-benzo[d]imidazol-2-yl)biphenyl (BImBP) as host material. By using 1,3,5-Tri(m-pyridin-3-ylphenyl)benzene (TmPyPB) as the electron-transporting material, we achieved a maximum current efficiency of 56.20 cd/A, power efficiency of 55.55 lm/W, external quantum efficiency of 26.85 %, and 4-times increase in operation lifetime in the blue PhOLED.