"1,3,2苯并二氮雜硼引入咔唑及苯并咪唑之合成、性質探討及其在藍色磷光有機發光二極體及陰離子偵測之應用"

Abstract

相較於一般以碳氮氧為基礎的有機電致發光材料，含硼材料的研究較為罕見。硼具有較低的親電性，因此將硼設計於分子架構中，有望提升材料的最低空置分子軌道（LUMO），並應用於藍色磷光有機發光二極體的材料中。我們引入等電子體的概念，將硼二氮與苯環整合成10pi電子系統，設計了以1,3,2,-苯并二氮雜硼為主架構的分子，並引入咔唑及苯并咪唑合成於不同位置，以調整其傳電洞及電子的能力。因1,3,2,-苯并二氮雜硼具有10個π電子及硼原子的空pz軌域，展現了獨特的光電性質，擁有高三重態能階之特性，期許此系列化合物能有效應用於藍色磷光有機發光二極體中。在元件部分，目前已將本系列的bcb作為主發光材料，FIrpic作為客發光材料之元件，此bcb元件的最大亮度為16030 cd/m2，最佳發光功率為33.2 lm/W，最佳發光效率為44.3 cd/A，而最大外部量子效率為22.28%；以bcb作為電子阻擋層材料，BImbp作為發光層，FIrpic作為客發光材料之元件，bcb元件的最大亮度為10150 cd/m2，最佳發光功率為39.09 lm/W，最佳發光效率為56.00 cd/A，而最大外部量子效率為28.26%。此外我們發現溶液中陰離子會與硼二氮分子作用，改變此化合物的螢光性質，因此我們進行不同離子的偵測實驗，目前初步測試，此系列化合物對於F-及OH-的顏色變化最為明顯，能於10-5M下以肉眼辨識。目前測試，此系列化合物有望作為多重離子偵測之應用。

Compared with carbon, nitrogen and oxygen atoms, boron atom has relatively low electron negativity. One may therefore expect that boron containing aromatic compounds should have a higher LUMO than other aromatic molecules. Surprisingly examples of boron containing OLED materials are rare. Therefore, we are interested in exploring this new area, including the synthetic methodologies and applications of boron containing compounds in phosphorescent organic light emitting diode.Considering that a combination of boron-nitrogen atoms are iso-electronic with a carbon-carbon moiety, we substitute the C=C fragment in indole by B-N to form 1,3,2-benzodiazaborole moiety. Having a 10πelectron array and an empty p orbital on boron, 1,3,2-benzodiazaborole show special photo-physical properties.The emission spectra reveal that 1,3,2-benzodiazaborole derivatives maintain high triplet energy. The electronic properties can be tuned by introducing carbazolyl and benzimidazolyl substituents; the electron and hole transport ability can therefore be fine adjusted so that the application in blue phosphorescent organic light emitting diode (PhOLED) become successful. A PhOLED device derived from bcb, a 1,3,2-benzodiazaborole type PhOLED host, exhibits the maximum luminance of 16030 cd/m2, the maximum current efficiency of 44.3 cd/A, the maximum power efficiency of 33.2 lm/W, and the maximum external quantum of 22.28%；as electron blocking layer as bcb, bcb maximum luminance of 10150 cd/m2, the maximum power efficiency of 39.09 lm/W, the maximum current efficiency of 56.00 cd/A, and the maximum external quantum of 28.26%。On the other hand, in an anion detection experiment, we discover that anions can bind with the molecules and the fluorescence properties can be significantly enhanced. In particular, fluoride ion and hydroxide ion can be detected by naked eye in 10-5M. These molecules have the potential application in sensor array for multi-anion detection.