卡唑、噁唑、三苯基胺衍生共聚高分子於電激發光元件之電洞傳輸層應用

Abstract

本實驗目的在於合成良好的電洞注入及傳輸材料以取代目前使用最為廣泛的PEDOT:PSS，並將此系列的高分子材料運用在有機電激發光元件中，試驗其作為電洞注入層及電洞傳輸層的性質並加以探討。合成出的高分子材料是分為兩大系統，第一系統是將具有電洞傳輸性質的具羥基之卡唑衍生物和三苯基胺衍生物依不同比例以異佛爾酮二異氰酸酯連接成聚氨酯型態的五種共聚合物。另一系統則是以具羥基之卡唑衍生物以及具有電洞阻擋性質和電子傳輸性質的噁唑衍生物依不同比例以異佛爾酮二異氰酸酯連接成聚氨酯型態的五種共聚合物。聚氨酯本身結構即具有良好的電洞傳輸效果，本實驗目的在這兩種系統中找出最佳比例條件的聚合物能運用在電激發光元件中讓元件發光效率及亮度有效提升。元件製備的部份分為兩個系列： 一、ITO/PU/Ir(ppy)3+t-PBD+PVK/Mg/Ag 單獨使用合成之聚氨酯為電洞注入及傳輸層並測量其發光性質，和標準元件1S1：ITO/Ir(ppy)3+t-PBD+PVK/Mg/Ag之發光性質比較，相較於S1，亮度可從296 cd/m2有效提升至14000 cd/m2。效率也由1.02 cd/A提升至13.4 cd/A，顯示本實驗合成之聚氨酯材料用於電洞注入及傳輸層對元件發光亮度及效率有顯著提升。 二、ITO/PEDOT:PSS/PU/Ir(ppy)3+t-PBD+PVK/Mg/Ag 此系列元件引入作PEDOT為電洞注入層，以合成之聚氨酯作為電洞傳輸層。 將這一系列元件和標準元件S2：ITO/PEDOT:PSS/Ir(ppy)3+t-PBD+PVK/Mg/Ag 發光性質比較。在此系列中，相較於標準元件S2，亮度可由6250 cd/m2有效 提升至12500 cd/m2。效率也由21.8 cd/A大幅提升至34.7cd/A，顯示本實驗合 成的電洞傳輸材料對於提升元件效能有極大助益。

In this thesis, two series of hole-injecting and hole-transporting materials are synthesized and characterized. These two series are (1) TRI-IPDI-Cz series, triarylamine derivatives (denoted as TRI) and Carbazole derivatives (denoted as Cz) linked by isophorone diisocyanate with different ratios to form a series of polyurehtanes (PU) and (2) Cz-IPDI-OXD series, were synthesized in a similar fashion as (1) only with different monomers, oxadiazole derivatives, denoted as OXD. These materials are applied in electroluminescent device as hole-injecting and hole-transporting layer to improve the performance. The devices are separated into two systems: a. ITO/PU/Ir(ppy)3+t-PBD+PVK/Mg/Ag : PUs were applied in the devices and the devices were compared with the standard device S1:ITO/Ir(ppy)3+t-PBD+PVK/Mg/Ag. The brightness was increased to 14000 cd/m2, the current efficiency rose to 13.4 cd/A and turn-on voltage was reduced to 21V (at 100 cd/m2), compared to 296 cd/m2, 1.02 cd/A and 37 V in S1; and b. ITO/PEDOT:PSS/PU /Ir(ppy)3+t-PBD+PVK/Mg/Ag, compared to standard device S2: ITO/PEDOT:PSS/ Ir(ppy)3+t-PBD+PVK/Mg/Ag. The brightness was increased to 12500 cd/m2, the current efficiency was up to 34.7cd/A, compared to 6250 cd/m2 and 21.8 cd/A in S2.