有機發光二極體化學材料的合成與性質研究

Abstract

本論文分為兩部分，分別針對distyrylarylene衍生物與藍色磷光錯合物的主發光體材料之合成、性質與元件做討論。 在A部分中，我們將四個fluorene基團共價鍵結到DSA衍生物DPAVBi上，合成出新的淺藍色螢光材料，並與一橘紅光phosphor摻混進PVK與PBD的混合基質中，製作白光高分子元件。Fluorene基團有助於抑制phosphor三重激發態能量回傳所帶來的能量損耗，進而提升白光元件的效率。 在B部分中，我們合成出兩個可以應用於藍色磷光元件的主發光體材料。兩材料分別以9-phenylcarbazole或triphenylamine增加電洞的傳輸能力，搭配有助於傳遞電子的triphenylphosphine oxide基團，使之具有bipolar的性質。而在分子設計上，中心碳原子以sp3軌域鍵結周圍的取代基，能夠避免分子共軛長度增加，確保兩主發光體材料具有比一般藍光phosphor還要高的三重激發態能階(~3.0 eV)。

This thesis is divided into two parts regarding the synthesis and characterization of distyrylarylene derivatives for the blue component in white polymer light-emitting diodes (PLEDs) and two new host materials for blue-light-emitting electrophosphorescent devices. In part A, we have synthesized a blue fluorescent emitter (F-DPAVBi), amino-substituted distyrylarylene derivative encapsulated with fluorenyl groups. We have demonstrated that the bulky fluorenyl dendrons play an important role to inhibit the undesired back energy transfer causing the nonradiative decay. By reducing this loss mechanism for light generating, the efficiency of the white-electrophosphorescent device through incorporation of F-DPAVBi and an orange osmium phosphor into a nonconjugated polymer blends (PVK-PBD) can be improved. In part B, two bipolar host materials for phosphorescent OLEDs were synthesized throught combining the hole-transporting groups (9-phenylcarbazole or triphenylamine) and the electron-transporting groups (triphenylphosphine oxide) with the sp3 orbital of central carbon atom. Because the central carbon atom effectively interrupt any extended π-conjugation, the triplet energies of these two host materials are as high as 3.0 eV, which is sufficient to confine the triplet excitons on the blue phosphorescent dopant materials (in this work, FIrpic and FIrfpy) and ensure the performance of blue-light-emitting electrophosphorescent devices.