以四苯基矽烷主體材料及施體-受體-受體發光材料製作有機發光二極體之研究

Abstract

本篇論文研究主題有二。其一為以四苯基矽烷衍生物為主體材料製作高效率藍色磷光與綠色熱活化延遲螢光有機發光二極體，其二為運用具施體-受體-受體分子構型之發光材料製作長波長放光元件。 我們利用臺大化學所梁文傑實驗室提供的四種四苯基矽烷衍生物為主體材料製作高效率有機發光二極體。該四種化合物以高三重態能量的四苯基矽烷作為分子核心，連接具電洞傳輸特性的咔唑基團和具電子傳輸特性的咔啉基團期望達到雙極性載子傳輸特性。在這四種化合物中，9-(4-((4-(9H-pyrido[2,3-b]indol-9-yl)phenyl)diphenylsilyl)phenyl)-9H-pyrido[2,3-b]indole (Dialpha-CbSi) 在元件發光層中提供較佳的電子電洞平衡因而達到最高的元件效率。藉由調變客發光體材料摻雜濃度及元件內各膜層厚度，在Dialpha-CbSi中摻雜bis[2-(4,6-difluorophenyl)pyridinato-C2,N](picolinato)iridium(III) (FIrpic)之藍色磷光有機發光二極體其最佳電流效率、功率效率和外部量子效率分別為57.17 cd/A、51.31 lm/W和26.35%。而在Dialpha-CbSi中摻雜2,4,5,6-tetrakis(carbazol-9-yl)-1,3-dicyanobenzene (4CzIPN)之綠色熱活化延遲螢光有機發光二極體其最佳電流效率、功率效率和外部量子效率分別為83.59 cd/A、75.03 lm/W和23.73%。 我們將臺大化學所汪根欉實驗室提供具施體-受體-受體分子構型之發光材料7-(4-(di-p-tolylamino)phenyl)benzo[c][1,2,5]thiadiazole- 4-carbonitrile (DTCPB)導入不同的主體發光體系統製作長波長放光元件，包含螢光主體系統、激發錯合物主體系統及熱活化延遲螢光輔助主體系統。在熱活化延遲螢光輔助主體系統中摻雜1%的DTCPB使元件放光頻譜峰值落在623 nm並具有6.67%的外部量子效率。

There are two topics in this thesis. The first one is high efficiency blue phosphorescent and green thermally activated delayed fluorescence (TADF) organic light-emitting diodes (OLEDs) using tetraphenylsilane derivatives as host materials. The second is organic light-emitting diodes with long wavelength emission (near infrared (NIR) to red) by employing an emitting material with donor-acceptor-acceptor molecular configuration. We used four tetraphenylsilane derivatives, which are supplied by Prof. Man-Kit Leung’s group, as host materials for high efficiency OLEDs. These compounds have a high-triplet-energy tetraphenylsilane as core, jointed with hole-transporting carbazole and electron-transporting carboline substituents. Among the four compounds, device using 9-(4-((4-(9H-pyrido[2,3-b]indol-9-yl)phenyl)diphenylsilyl)phenyl)-9H-pyrido[2,3-b]indole (Dialpha-CbSi) as host material has highest efficiency due to good charge balance in the emitting layer (EML). By optimizing dopant concentration, thickness of electron transporting layer (ETL) and EML, the Dialpha-CbSi-based OLEDs achieve 57.17 cd/A, 51.31 lm/W and 26.35% in current efficiency, power efficiency and external quantum efficiency (EQE) with blue phosphor dopant, bis[2-(4,6-difluorophenyl)pyridinato-C2,N](picolinato)iridium(III) (FIrpic), while achieving 83.59 cd/A, 75.03 lm/W and 23.73% in current efficiency, power efficiency and EQE with green thermally activated delayed fluorescent (TADF) dopant, 2,4,5,6-tetrakis(carbazol-9-yl)-1,3-dicyanobenzene (4CzIPN). We introduced a donor-acceptor-acceptor molecular configuration emitter, 7-(4-(di-p-tolylamino)phenyl)benzo[c][1,2,5]thiadiazole-4-carbonitrile (DTCPB), which is supplied by Prof. Keng-Tsung Wong’s group, into fluorescent, exciplex and TADF assistant host matrixes for pursuing long wavelength emission. By incorporating 4CzIPN as TADF assistant host, the OLED doped with 1% DTCPB has an emission peak wavelength of 623 nm and red EQE of 6.67%.