具分子內三重態-三重態煙滅有機材料之設計、合成與元件應用

Abstract

相較於傳統的薄膜電晶體液晶顯示器 (Thin film transistor liquid crystal display, TFT-LCD)，有機發光二極體 (Organic Light-Emitting Diode, OLED)，具有可撓曲、重量輕、厚度薄、高對比、應答速度快等優勢，已經廣泛應用於商業市場上。應用於OLED的材料開發方興未艾，特別是具有高效率、高穩定性的藍光材料有許多挑戰。 本論文分為兩部分，第一部分為具有分子內三重態-三重態煙滅 (Triplet–triplet annihilation, TTA) 的藍光材料分子，第二部分是以N-環化苝 (N-annulated perylene) 為主體的分子。相關材料的性質，將於本文中透過光物理及元件結果分析，探討分子結構、物理特性與元件效能之間的關係。 為了更有效運用到三態激子，避免於元件中過度累積，進而提升元件穩定度與效率，我們開發出具有分子內TTA性質的分子，分別以吖啶 (acridine) 及芘 (pyrene) 作為功能基團，並以不同官能基團 (如芴、醚、甲基碳橋、三氟甲基碳橋) 連接，合成出一系列具有近距離功能基團的有機分子材料，探討構形變化對分子內TTA效果之影響。此外，以N-環化苝 (N-annulated perylene) 為核心，在3,10號位置引入推電子基，合成出具強推電子能力之電洞傳輸材料，搭配適當的電子傳輸材料，進而產生深紅光之激發複合體 (exciplex)。另外，改以在3,10號位置分別引入拉電子基及推電子基，藉由推拉電子效應 (push-pull effect)，調控放光光色變化，探討系列分子之光物理性質。

Organic light-emitting diodes (OLEDs) have already been commercialized with advantages such as mechanical flexibility, light weight, thin, high contrast, and fast response compared to those of traditional liquid crystal displays (LCDs). This thesis contains two parts. The first part is organic materials with intramolecular Triplet-triplet annihilation (intra-TTA) properties. The second part is N-annulated perylene derivatives. The characterized physical properties of these materials together with the results of their applications in OLEDs are explored to establish the relationship between molecular structure, physical properties and device performance. In order to utilize the triplet excitons more effectively for improving the efficiency of devices, the excessive accumulation of triplet exciton needs to be significantly avoided. In this regard, we developed blue emission molecules with intramolecular TTA properties. In which, acridine and pyrene were introduced as TTA functional groups respectively, which are connected by linkage such as fluorene, ether, carbon with methyl or trifluoromethyl. A series of blue emitters with close-distance of TTA functional groups were synthesized and characterized. The influence of configuration effect on intramolecular TTA mechanism was explored. In addition, electron-donating groups were introduced at 3 and 10 positions of N-annulated perylene to synthesize hole-transporting materials with strong electron-donating ability. By matching with appropriate electron-transporting materials, exciplex with deep red emission was yielded. Furthermore, electron-withdrawing groups and electron-donating groups were introduced at 3 and 10 positions of N-annulated perylene respectively to control the emission color through push-pull effect. The photophysical properties of these molecules were investigated.