白光及圓極化光之高效率有機發光材料與元件研究

有機發光二極體(Oragnaic Light-Emitting Diode, OLED)近年來已被視為重要的顯示及照明技術，許多裝配OLED之產品也已商品化，因此開發更高效率OLED的功能材料及元件已成為近期學術研究上探討的重點。本篇論文中，我們主要研究建構一套分析白光效率的方法以及研究圓極化OLED材料(Circularly Polarized OLEDs materials)。相較於單一發光材料之OLED效率分析，分析多個發光材料之白光OLED效率較為複雜且困難。那是因為不同發光材料之激子比例、受光學微共振腔影響和不同發光特性(例如:水平偶極矩)的影響需要同時考慮。因此在本論文之第一部份，我們利用藍光和橘紅光發光材料之高效率單發光層白光OLED，有系統、定量探討所有因子對白光OLED發光效率效果的光學模擬方法，可用於分析及開發高效率白光OLED。第二部分，在本論文我們研究了兩個具有手性(Chiral)對映體特性，為熱激活化延遲螢光並且擁有圓極化發光特性之發光材料，(S)-NPEI-DMAC and (R)-NPEI-DMAC。並以(S)-NPEI-DMAC and (R)-NPEI-DMAC為發光材料製作具圓偏極化發光特性之OLED，呈現高非對稱因子(g factor) +0.3/-0.38，同時擁有高達20.5%之元件外部量子效率，為有機手性小分子發光材料為基礎的CP-OLED的重要結果。第三部分，我們研究了擁有高量子效率之D*-A型圓偏極化熱激活化延遲螢光(Circularly Polarized Thermally Activated Delayed Fluorescence, CP-TADF)，透過整合高分子剛性和穩定的手性，藉此實現前瞻的藍光(TRZ-MeIAc)和橘光(NID-MeIAc)之圓偏極發光材料及元件。

關鍵字

白光有機發光元件；圓極化有機發光元件

並列摘要

Organic Light-Emitting Diodes (OLEDs) have been regarded as an important display and lighting technology in recent years. Many electronic products using OLED panels have been commercialized. Therefore, developing even higher-efficiency functional OLED materials and devices have become important research topics. In this dissertation, we study the methods for analyzing emission efficiency of white-emitting OLED and study circularly polarized OLED (CP-OLED) materials and devices. Analyses of light extraction/out-coupling efficiencies of white OLEDs having multiple emitters are much more complicated and difficult than single-emitter monochromatic OLEDs, as ratios of excitons formed on different emitters, different optical (microcavity) effects on emission of different emitters, and effects of emission characteristics (e.g., emitting dipole orientations) of different emitters etc. need to be considered simultaneously. The first part of this thesis study, we report efficient single-emitting-layer white OLEDs adopting blue and orange-red emitters and a systematic and quantitative optical simulation approach taking into account all these factors, for analyzing optical out-coupling efficiencies of single-emitting-layer multiple-emitter white OLEDs. It is believed to be useful for development of efficient white OLEDs. In the second part of this thesis study, two chiral pure enantiomers, namely (S)-NPEI-DMAC and (R)-NPEI-DMAC, were designed and synthesized as emitters for circularly polarized organic light-emitting diodes (CP-OLEDs). The CP-OLEDs based on (S)-NPEI-DMAC and (R)-NPEI-DMAC as emitters achieved very large electroluminescence dissymmetry factors of +0.30/−0.38, as well as high external quantum efficiencies up to 20.5%. These results represent a significant result in CP-OLEDs based on chiral organic small-molecule emitters. In the third part of this thesis study, by integrating high molecular rigidity and stable chirality, two pairs of D*–A type circularly polarized thermally activated delayed fluorescence (CP-TADF) emitters with an almost absolute quasiequatorial conformer geometry and excellent photoluminescence quantum efficiencies (PLQYs) were studied, achieving state-ofthe-art electroluminescence performance among blue (TRZ-MeIAc) and orange (NID-MeIAc) circularly polarized organic light-emitting diodes (CP-OLEDs).