有機或高分子發光二極體(OLEDs, PLEDs)已被譽為新一世代的平面顯示器，其原理為在施予一偏壓下，分別來自陽極與陰極注入之電洞及電子，藉由傳輸至發光層進行再結合而形成激子，並釋放出光而回至基態。而若要達到高的發光效率，傳輸至發光層內的載子平衡極為重要；然而大部分有機材料中，電洞的傳輸速度比電子來得快，易造成載子不平衡，再結合比率低，而降緩電洞的載子傳輸速率則是有效改善有機發光二極體元件效率的方法之一。此外，傳統上多層OLED元件以真空蒸鍍的方式成膜製備，但由於需操作在高溫且低壓條件下，因此製備複雜且成本較高。故本研究設計並合成出可用於濕式製程的電洞緩衝材料，以提高元件效率，亦能降低製備成本。
本研究利用Suzuki Coupling Reaction與Schiff Base Condensation Reaction合成出外圍含有三個希夫鹼基團之1,2,4-三氮唑(TAZS)及三苯胺(TPAS)，以核磁共振光譜(1H NMR、COSY) 、紅外線光譜儀(FTIR)、基質輔助雷射脫附游離飛行質譜儀(MALDI/TOF-MS)鑑定其結構，並分析其水解性質、熱性質、光學性質、電化學性質、膜態及元件特性。最後將其作為電洞緩衝層(Hole-Buffer Layer: HBL)，製備PLED多層元件。
實驗發現，TPAS容易水解，而TAZS則較為穩定；熱性質方面，TAZS熱裂解溫度為264 oC，且因主體外圍的希夫鹼基團使其不易聚集排列而產生結晶，因此並無觀察到結晶峰；TAZS的薄膜態螢光放光峰為527 nm，而其量子效率低，可避免影響元件發光光色；從循環伏安法得到TAZS之LUMO/HOMO能階為-2.40/-5.23 eV，比較其LUMO及HOMO能階位置相對於發光層，TAZS不僅能緩衝電洞進入發光層，同時也具有侷限電子於發光層的特性。本研究以旋轉塗佈法將TAZS塗佈於電洞注入層(PEDOT:PSS)上作為電洞緩衝層(HBL)製備多層螢光元件(ITO/PEDOT:PSS/HBL/SY/LiF/Al)；在無加入電洞緩衝層之元件最大亮度為8,484 cd/m2，最大電流效率為2.13 cd/A，而加入TAZS作為電洞緩衝層後，最大亮度提升至19,047 cd/m2，最大電流效率亦提升至4.08 cd/A。
研究結果顯示，加入TAZS作為元件之電洞緩衝層可以使電洞及電子在發光層中更加平衡；TAZS不僅能減緩電洞傳輸的能力，也具有電子阻擋特性，大幅提升元件之表現，並且能以濕式製程的方式塗佈製作，在電洞緩衝材料的應用上具有發展潛力。

In recent years, solution-processed polymer light-emitting diodes (PLEDs) have been widely studied owing to its low energy consumption, self-emissive ability, and fast response time in solid-state lighting application. In this work, we successfully synthesized a new material, TAZS (1,2,4-triazole as main group) and TPAS (Triphenylamine as main group), containing trihydroxy tert-butyl groups. The hydrolysis test indicates that TPAS is easily hydrolyzed but TAZS is much more stable in water. TAZS was applied as efficient hole buffer layer by solution process which can reduce hole mobility to increase PLED efficiency. TAZS possess well morphology because of non-crystalline characteristic. In electrochemical measurement, HOMO and LUMO levels were -5.23 and -2.40 eV, respectively. Multilayer PLEDs were fabricated by spin-coating process with a configuration ITO/PEDOT:PSS/TAZS/SY/ETL/LiF/Al. The best performance of TAZS device (maximum luminance: 19,046 cd/m2, maximum current efficiency: 4.08 cd/A) was superior to the device without TAZS (8,484 cd/m2, 2.13 cd/A). These results demonstrate that TAZS was a potential use for hole buffer material.

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