摘要

高分子發光二極體(Polymer Light Emitting Diode, PLED)始於1990年英國劍橋大學Friend等人的研究，發現共軛高分子可做為發光二極體材料，從此開啟了高分子發光二極體的時代。
聚茀( Polyfluorene)，具有良好的熱安定、化學穩定性，且具有很高的螢光量子效率(Fluorescence Quantum Efficiency)，螢光放射波長涵蓋在400～460 nm(藍光)，很適合作為發藍光的結構。但是Polyfluorene光學穩定性不佳，容易有激發雙體、凝集或是分子因氧化生成酮基(Fluorenone)，而改變發光顏色，降低ΦPL而大大限制其應用性。
Triazole是很好的電子注入傳送材料，藉由Triazole的導入高分子中可以提升電子注入的能力，而改善電荷注入的平衡，增加高分子發光效率。
本研究為了探討Triazole構形對於Polyfluorene的光學穩定性、電化學及元件等的影響，利用Suzuki Reaction，將Fluorene分子與Triazole分子聚合成一系列的高分子。由實驗結果發現，在物理性質方面，P2~P7可以溶於一般的溶劑，如CHCl3、NMP、C2H2Cl4，有利於元件的加工。光學方面，高分子發光主要由Fluorene所貢獻，導入Triazole基團可以改善部分高分子的光學熱穩定性。電化學性質方面，其HOMO與LUMO能階分別為 -5.61, -5.62, -5.61, -5.62, -5.65, -5.62, -5.62eV 與 -2.52, -2.67, -2.70, -2.71, -2.80, -2.82, -2.75 eV。導入Triazole基團之後，可以降低高分子的LUMO能階，使電子注入較容易。但是在電激發光時，高分子的發光依然會有Excimer產生的現象，而使發光光色隨驅動電壓而改變，但隨著Triazole的加入，可以降低Excimer部分的發光，並改善其光色純度。

Abstract

Since the discovery of electroluminescence(EL) in the poly(1,4-phenyl-
enevinylene) (PPV) in 1990, EL conjugated polymers have attracted much interest in recent years because of their potential application in large-area flat panel displays.In the past decade, fluorene-based conjugated polymers (PFs) have emerged as a very promising class of blue-light emitting materials for use in PLEDs because of their high thermal stability, high electroluminescence quantum efficiencies. However, one drawback has limited the application of polyfluorene in blue PLED .For example, excimer , aggregation and fluorenone were observed and the formation of these interaction reduced PL and EL efficiency.
To solve this problem in this study, we prepared a series of fluorine based copolymers with triazole segment aiming to investigate the conformations of copolymers affecting optical stability. The influences of the conformations of triazole on photophysical, electrochemical, and electroluminescent properties of the resulting polymers. The copolymers were soluble in common solvents such as chloroform, NMP, and 1,1,2,2-tetrachloroethane and exhibited good thermal stability with Tds higher than 400℃. The emission of P1~P7 are dominated by the fluorene segment . Furthermore, the HOMO and LUMO energy level of P1~P7 , estimated from electrochemical data, are -5.61, -5.62, -5.61, -5.62, -5.65, -5.62, -5.62eV and -2.52, -2.67, -2.70, -2.71, -2.80, -2.82, -2.75 eV, respectively. It can lower the LUMO energy level . Double-layer light emitting diodes of P1~P7 reveal emission maxima around 480~550 nm. There are still excimer emission and the color changes with the driving voltage . But with the increasing of the triazoles, it can suppress the excimer emission and improve the purity of color.

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