含三伸苯之三苯胺衍生物的合成、電化學研究 及在有機光電元件的應用

Abstract

近年來盤狀液晶分子在學術領域上占有相當重要的地位。盤狀液晶分子具有盤狀的核心與柔軟的側鏈，由於分子具有多苯環的核心，所以有良好的π-π堆疊而能使盤狀液晶堆疊成柱狀結構，此外核心具有多電子的結構因此適合做為電洞傳導用途。 本篇論文的研究主旨是採用類似盤狀液晶的合成方式，以三伸苯(triphenylene)作為分子的核心，藉由改變不同的三苯胺及咔唑醚基側鏈來合成目標化合物7、11、15、19、21，並觀察分子的光學性質變化，電化學行為，以及作為電洞傳輸材料在有機電激發光元件上的效果。 在光學研究方面，由於目標化合物內單體的HOMO及LUMO能階差異，使得在溶液螢光放射上有雙發射及能量轉移的情形發生；在電化學研究方面，不同的三苯胺衍生物由於氧基的位置不同，使得取代基在間位的化合物有不錯的電聚合效果；而元件的應用上，具有咔唑基團的化合物21由於在形成電聚薄膜後，可能有殘餘的陽離子態化合物，使得電聚薄膜內的電洞數濃度較高，因此與其他元件相比之下，有較低的啟動電壓和不錯的元件效率。

Discotic liquid crystal molecules play very important role in academical research field recently. In terms of the structures of discotic liquid crystal molecules, they have a discotic core and flexible side chains. In addition, they also have π-π interaction such that they have stacking properties and can become columnar structures because of their central polymeric core. Therefore, the discotic liquid crystal moleculs can become hole-transport materials due to central polymeric and electon-rich core. We adopt a similar discotic liquid crystalline synthesis way to synthesize target molecules 7, 11, 15, 19, 21 in this article. The target molecules have a central triphenylene core and different side chains including triphenylamine derivatives and carbazole molecules. We observe these molecules optical and electrochemical properties and the effect of hole-transport layers in organic light emitting diode (OLED). In the results of the optical properties, these molecular monomers have different HOMO and LUMO energy gap such that there are dual-emission and energy transfer mechanism in solution fluorescence spectrum. In the study of the electrochemical properties, various of triphenylamine derivaties have different oxygen binding site and they make elecropolymerization happen or not. In the applications of the hole-transport materials, the performance of compound 21 is better than other compounds. The electropolymerized-film may have residual cation molecules so they can increase the concentration of hole-transport. Due to this reason , compound 21 is suitable to become hole-transport materials.