聚-(2,3-雙苯基-1,4-仲苯基乙烯)黃光共聚物 之合成及其高分子電激發光元件上之應用

Abstract

本研究主要目的在合成新穎發光高分子材料並探討其在有機發光二極體上之應用。論文中總共合成了一種均聚合物及七種共聚合物(SY1 ~ SY7)，主要設計為改良從前DP-PPV衍生物的長碳鏈造成高分子鏈螺旋的缺點，將碳鏈轉移到側鏈的苯環上而合成出DP(OC6)-PPV單體，將本單體以t-BuOK進行聚合，形成均聚合物DP(OC6)-PPV，並將本單體與DMeO-PPV、meta-Phenyl PPV與MEH-PPV之單體導入進行共聚反應，合成出七種共聚合物，所合成八個聚合高分子分子量均大於190000，且熱分解溫度高於400 oC，玻璃轉換溫度最高可達143 ℃，導入了DMeO-PPV和meta-Phenyl PPV做共聚，有助於提升電子傳輸速度，並改善元件之效率，其中SY3的亮度為11500 cd/m2且最大效率4.36 cd/A，最大亮度為SY5甚至可達13400 cd/m2。 SY6和SY7成功的導入了MEH-PPV不但溶解度問題得到解決，並且依舊有具有改善電洞傳輸速度的能力，特別在40 mol % 導入的SY7，可以得到亮度為12000 cd/m2且最大效率2.22 cd/A，CIE色度座標值為(0.49,0.50)，光色可達黃光，相較於文獻，元件結果也有不錯的表現。

The goal of this study is aimed to synthesize some new poly(2,3-diphenyl-1,4-phenylene vinylene) (DP-PPV) derivatives for the application in polymer light-emitting diodes. Our previous synthesized DPn-PPV containing hexyl alkyl chain on the PPV backbone, has the tendency to form order helical structure. This is a major drawback for high efficiency PLED device. In this study, we introduce an ethyl-hexyl group on the phenyl substituent of DP-PPV monomer of DP(OEH)-PPV. Besides the homopolymer of DP (OEH)-PPV, this monomer will copolymerize with monomers of DMeO-PPV, m-Ph-PPV and MEH-PPV to form seven kinds of copolymers SY1 ~ SY7. The molecular weight of all polymers are higher than 190000. Their degradation temperatures (Td) are higher than 400 oC. Their glass transition temperatures are in the range from 53 to 143 oC. According to literatures, introducing the DMeO-PPV and m-Ph-PPV moieties into the polymer main chain will increase the electron mobility of the obtained polymers. This will also increase their PLED efficiency. Among eight polymers, SY3 shows a brightness of 11500 cd/m2 and an efficiency of 4.36 cd/A. The highest brightness of 13400 cd/m2 is achieved by copolymer SY5. For SY6 and SY7 containing MEH-PPV moiety, show much higher solubility. Copolymer SY7 shows a brightness of 12000 cd/m2 and an efficiency of 2.22 cd/A. Its CIE coordinate is (0.49, 0.50). It emits the yellow light. In comparison with literatures results, this yellow emitter has relatively good device performanace.