具備熱活化延遲螢光之吖啶-喹唑啉綠色發光體以及三重態-三重態融合特性之芘基-三苯基鄰三聯苯藍色發光體應用於有機發光二極體研究

Abstract

本篇論文中包含兩個主題，首先，我們成功展示了兩種基於不同激子收集機制的高效能有機發光二極體（OLED），分別是熱活化延遲螢光（TADF）和三重態-三重態融合（TTF）。第一個主題是針對綠光TADF OLED應用，我們開發了兩種新的基於嘧啶的TADF發光材料，分別是 10,10'-((5-fluoroquinazoline-2,4-diyl)bis(4,1-phenylene))bis(9,9-dimethyl-9,10- dihydroacridan) (4Ac5FQN) 和 10,10''-((5-fluoroquinazoline-2,4-diyl)bis(4,1-phenylene))bis(10H-spiro[acridan9,9'-fluorene]) (4SpAc5FQN)，它們分別展現出 20.2% 和 22.1% 的卓越外部量子效率（EQE）。這兩者的單重態-三重態能隙（ΔEST）分別為 0.02 eV 和 0.07 eV，促進了高效的反向系統間交叉（RISC），進一步證明了它們強大的TADF潛力。 此外，在第二個研究主題中，我們還探索了基於藍光 TTF 的 OLED，使用了兩種新合成的芘基衍生物 1-(3′,4′,5′-triphenyl-[1,1′:2′,1″-terphenyl]-4-yl)pyrene (1PyrB4ph) 和 1,1'-(4′,5′,6′-triphenyl-[1,1′:2′,1″-terphenyl]-3′,4″-diyl)dipyrene (1PyrB4phPyr)。通過引入四苯基苯（4Ph）單元，有效增加了分子間距離，從而提升了分子排列並改善了角度穩定性，這一點在角度依賴光致發光（ADPL）測量中得到了驗證。這些材料的最大外部量子效率分別為 11.39% 和 10.07%。瞬態電激發光（TrEL）測量顯示出顯著的延遲發光比例，分別為 18% 和 9%，這些現象歸因於 TTF 機制，並通過磁場電激發光（MEL）分析進一步確認。據我們所知，這些是目前報告中在芘基 OLED 中最高的 TTF 貢獻。本研究突顯了剛性 TADF 發光材料和 TTF 支持的主體材料在開發高效且穩定的 OLED 中的潛力，並可應用於整個可見光譜範圍。

There are two topics in this thesis First, we successfully demonstrated two categories of high-performance organic light-emitting diodes (OLEDs) based on distinct exciton harvesting mechanisms: thermally activated delayed fluorescence (TADF) and triplet–triplet fusion (TTF). The first topic focused on green TADF OLED applications, where we developed two novel quinazoline-based TADF emitters, 10,10'-((5-fluoroquinazoline-2,4-diyl)bis(4,1-phenylene))bis(9,9-dimethyl-9,10- dihydroacridan) (4Ac5FQN) and 10,10''-((5-fluoroquinazoline-2,4-diyl)bis(4,1-phenylene))bis(10H-spiro[acridan9,9'-fluorene]) (4SpAc5FQN), which exhibited excellent external quantum efficiencies (EQE) of 20.2% and 22.1%, respectively. Their small singlet–triplet energy gaps (ΔEST) of 0.02 eV and 0.07 eV facilitated efficient reverse intersystem crossing (RISC), further confirming their strong TADF potential. Furthermore, in the second topic, we explored blue TTF-based OLEDs using two newly synthesized pyrene derivatives, 1-(3′,4′,5′-triphenyl-[1,1′:2′,1″-terphenyl]-4-yl)pyrene (1PyrB4ph) and 1,1'-(4′,5′,6′-triphenyl-[1,1′:2′,1″-terphenyl]-3′,4″-diyl)dipyrene (1PyrB4phPyr). By incorporating tetraphenylbenzene (4Ph) units, we effectively increased intermolecular spacing, which improved molecular alignment and enhanced angular stability, as verified by angle-dependent photoluminescence (ADPL) measurements. These materials achieved maximum external quantum efficiencies of 11.39% and 10.07%, respectively. Transient electroluminescence (TrEL) measurements showed significant delayed emission ratios of 18% and 9%, which were attributed to the TTF mechanism and further confirmed by magneto-electroluminescence (MEL) analysis. To the best of our knowledge, these represent the highest reported TTF contributions in pyrene-based OLEDs. This study highlighted the potential of both rigid TADF emitters and TTF-enabled host materials in the development of highly efficient and stable OLEDs, with applications across the entire visible spectrum.