高分子發光二極體(PLEDs)原理是外加一偏壓驅動電洞與電子分別從陽極和陰極注入，遷移至發光層再結合後放出光，所以載子的注入與傳輸對於元件效率有密切關係。然而大部分有機材料，在元件內電洞的移動速率較高於電子，導致發光層中電洞與電子數目不平衡，再結合比率下降，所以欲提高元件效率除了改變材料特性外，降低電洞注入與傳輸速率是有效方法之一。
本研究以Suzuki coupling以及亞胺反應成功合成側鏈含三羥甲基與希夫鹼基團聚芴高分子(PFT)，並作為電洞緩衝層(HBL)應用於高分子有機發光二極體。PFT高分子經由核磁共振光譜(1H-NMR)及元素分析(EA)鑑定其結構，並分析其熱性質、光學性質及電化學性質、最後探討膜特性以及元件光電性質。PFT的熱裂解溫度(Thermal Decomposition Temperature, Td)為220oC，有高玻璃轉移溫度(Glass Transition Temperature, Tg)為122 oC；由循環伏安法計算得PFT 的HOMO和LUMO能階分別為-5.59 eV和 -2.71 eV。成功利用濕式製程的旋轉塗佈注膜製備元件 [ITO/PEDOT:PSS/HBL/SY-PPV/LiF/Al]，其元件最大亮度為17,292 cd/m2，最大電流效率為6.99 cd/A，優於無加入電洞緩衝材料之元件[ITO/PEDOT:PSS/ SY-PPV/LiF/Al](8,128 cd/m2, 2.32 cd/A)。
由研究結果顯示，以PFT為電洞緩衝層能有效的提高電荷在結合比率，大幅提升元件的發光效率，另外，PFT能夠以濕式製程成膜，元件製程簡單且成本低，綜合以上兩特點PFT作為電洞緩衝材料具有發展潛力。

Balanced carriers’ injection and transport is essential to obtain high emission efficiency in polymer light-emitting diodes (PLEDs). Generally, the injection and transport of holes are faster than electrons, leading to imbalanced carriers in emission layer (EML) and degraded device performance. Reduction of hole injection and transport (hole-buffer) is one of the effective ways to enhance device performance.
In this study, we have synthesized a polyfluorene derivative (PFT) by the Suzuki coupling reaction and imine formation. The PFT is composed polyfluorene main chain and pendant tris(hydroxymethyl) and imine (Schiff base). PFT possesses high glass temperature (Tg > 100 oC) and thermal decomposition temperature (Td,5% was about 220 oC). The HOMO and LUMO energy levels of PFT were -5.59 eV and -2.71 eV, respectively as estimated from onset oxidation and reduction potentials obtained in cyclic voltammetric measurements. Multilayer PLEDs [ITO/PEDOT:PSS/PFT(HBL)/SY-PPV/LiF/Al] have been successfully fabricated using spin-coated PFT as HBL. The maximum luminance and maximum current efficiency were 17,292 cd/m2 and 6.99 cd/A, significantly higher than the device without HBL (8,128 cd/m2, 2.32 cd/A).Our results indicate that PFT is an effective hole-buffer material that can be deposited by spin-coatong process.

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