應用新穎藍光熱激活化延遲螢光材料之高效率藍光及白光有機發光元件

Abstract

有機發光二極體已被視為重要的顯示技術與照明技術，所以元件效率備受重視，尤其藍光與白光元件是近期在學術研究上探討的重點。因此在本篇論文中，我們針對新穎的熱激活化延遲螢光材料做光物理與電性上的分析，並進一步製作高效率的藍光與白光有機發光元件。 在論文的第一部份，我們針對新穎的acridine-triazine系列材料進行光物理的分析，得知它們為高效率的熱激活化延遲螢光(TADF)藍光發光材料。其中SpiroAC-TRZ具有接近理想的100%量子效率(PLQY)和很高的水平偶極方向性(horizontal dipole ratio)。在仔細優化元件的電性及光學特性下，製成的藍光元件其外部量子效率可高達37%，是目前熱激活化延遲螢光有機發光元件及各種藍光有機發光元件當中，效率最高的紀錄。 第二部分我們利用SpiroAC-TRZ很好的藍光光物理以及元件特性，將SpiroAC-TRZ與其他紅光的磷光有機發光材料同時摻雜在單一發光層中，製作出外部量子效率超過32%的白光有機發光元件。

Organic light-emitting diodes (OLEDs) have become an important technology for display and lighting applications. To enhance OLED performances for various applications, continuously improving efficiencies of blue and white OLEDs (WOLEDs) is critical. In this thesis, we focused on the investigation of high performance organic light-emitting materials and device architectures based on thermally activated delayed fluorescence (TADF). In the first part, we investigated detailed photophysical properties of molecular materials based on the acridine-triazine hybrid. Our studies indicate they are highly efficient TADF emitters. Therein, SpiroAC-TRZ has unitary photoluminescence quantum yield (PLQY) and strongly horizontally oriented emitting dipoles simultaneously. It can be used to fabricate extremely efficient blue OLED with external quantum efficiency (EQE) of nearly 37%, by far the highest ever reported for TADF OLEDs and for all kinds of blue OLEDs. In the second part, we develop WOLEDs based on the extremely efficient blue OLED by incorporating SpiroAC-TRZ and other red phosphorescent emitters into a single-emitting layer (S-EML) device architecture. With the promising characteristics of SpiroAC-TRZ, WOLEDs with EQE exceeding 32% were obtained.