新型雙性材料之合成及其在有機電激發光二極體元件上之應用

Abstract

本研究主要目的在於利用Suzuki coupling方法成功合成出雙性磷光主體發光有機材料，運用在OLED元件上，最後探討其結構上的特性並討論其在有機發光二極體之應用的結果。 本論文主題分為兩部分，A部分:我們探討磷光主發光體的合成以及其結構上的特性；B部分:利用我們所合成出的PST-1~PST-3，製作成磷光與螢光元件。 A部分: 在合成方面，我們改變不同的中心 (M1、M3、M4)分別與具有傳遞電子能力的單體M1去聚合，成功合成出三個PST-1~PST-3雙性主發光體材料 (host)。從光學性質得知，PST-1、PST-2為藍光材料，PST-3為綠光材料。在熱性質分析上，可發現PST-1~ PST-3三個材料的Td點均大於400 oC，可見其熱穩定性都不錯。此性質對於元件的製作有很大的幫助。根據CV及UV-vis吸收光譜，計算出分子的HOMO及LUMO能階，得到PST-1~ PST-3的Eg均大於3 eV以上，這對於主發光體材料 (host)來說是個很大的優點，容易涵蓋到客發光體的能階，使能量轉移更有效率地達成。 B部分: 將我們所合成的PST-1~ PST-3製作成螢光元件以及磷光元件。 螢光元件當中，綠光元件PST-3效率最高達2.9 cd/A，亮度最高達390 cd/m2。藍光元件PST-1效率最高達2.4 cd/A，亮度最高達991 cd/m2。藍光元件PST-2效率最高達2.7 cd/A，亮度最高達479 cd/m2。我們也成功利用各種紅色磷光體摻混製作成紅光磷光元件。 在紅色磷光元件當中，PST-1在摻混Ir(btp)2(acac) 15 wt%時達到最高效率2.0 cd/A，1.4 lm/W；PST-2在摻混Ir(mpiq)2(acac) 5 wt%時達到最高效率3.5 cd/A，2.1 lm/W，最高亮度達2110 cd/m2；PST-3在摻混Ir(mpiq)2(acac) 5 wt%時達到最高效率4.1 cd/A，2.4 lm/W，最高亮度達2720 cd/m2。 在白色磷光元件當中，PST-2在摻混Ir(btp)2(acac) 0.15 wt%時達到最高效率2.1 cd/A，1.3 lm/W，最高亮度達1114 cd/m2；PST-2在摻混Ir(btp)2(acac) 0.1 wt%，最高亮度達1159 cd/m2。

This study is aimed at synthesizing several bipolar host organic light emitting materials via Suzuki coupling method. We also used these novel bipolar materials to fabricate OLED devices. Finally, the properties of compounds and devices are discussed. This thesis consists of two sections. In section A, we discuss the synthesis and characterization of bipolar hosts materials we made. In section B, we fabricate two kinds of devices: fluorescence and phosphorescence devices, respectively, and show the efficiency of the devices. In section A, we have synthesized three bipolar host materials PST-1~ PST-3 applicable in electrophosphorescent devices. We changed the different cores (M1, M3, M4) and individually coupled with M2 which has the electron transporting ability. From optical quality point of view, PST-1 and PST-2 are blue materials, and PST-3 is green material. From thermal property point of view, their degradation temperatures (Td) are higher than 400 oC, meaning they have required thermal stability to be used in devices. According to CV and UV-vis absorption spectrum, we calculate the value of HOMO and LUMO. The Energy bandgap of PST-1~ PST-3 are above 3eV. This is a great advantage for host materials as it can do energy transfer efficiently to guest material. In section B, we report the fabrication of PST-1~ PST-3 devices. In fluorescence devices, green material PST-3 shows the efficiency 2.9 cd/A, brightness 390.3 cd/m2, blue material PST-1 has the efficiency 2.4 cd/A, brightness 991 cd/m2, blue material PST-2 reaches the efficiency 2.7 cd/A, brightness 479 cd/m2. We also successfully fabricated the red and white electrophosphorescence devices by doping (btp)2Ir(acac) and Ir(mpiq)2acac into PST-1~ PST-3. In red electrophosphorescence devices, PST-1 doped with Ir(btp)2(acac) 15 wt% reaches the efficiency 2.0 cd/A, 1.4 lm/W; PST-2 doped with Ir(mpiq)2(acac) 10 wt% reaches the efficiency 3.5 cd/A, 2.1 lm/W，brightness 2110 cd/m2; PST-3 doped with Ir(mpiq)2(acac) 5 wt% reaches the efficiency 4.1 cd/A, 2.4 lm/W, brightness 2720 cd/m2. In white electrophosphorescence devices, PST-2 doped with Ir(btp)2(acac) 0.15 wt% reaches the efficiency 2.1 cd/A, 1.3 lm/W, brightness 1114 cd/m2; PST-2 doped with Ir(btp)2(acac) 0.1 wt% reaches the brightness 1159 cd/m2.