合成可溶性三氮唑分子以應用於溶液製程之有機發光元件

Abstract

本研究之目的在於合成出可溶性三氮唑衍生物(BEHP-TAZ)，探討其光學、電化學及熱性質，並評估其在三層發光元件之表現。其分子設計原則在於末端引入可溶性氧烷分岔支鏈以增加溶解度，兩端支鏈與三氮唑中心核之間則以苯環隔開，並藉以延長共軛。示差掃瞄卡計測試結果顯示其玻璃轉移溫度為84 oC；薄膜態之紫外-可見光最大吸收及螢光最大放射波長分別位於310及399 nm。循環電位分析搭配吸收光譜結果顯示其最高已填滿分子軌域、最低未填滿分子軌域及能隙分別為-5.86、-2.64及3.22 eV。本研究最後利用可溶性三氮唑分子作為電子傳輸層，以MEH-PPV或PFO為發光層，製作三層發光元件，並與雙層發光件比較之。實驗結果證明可溶性三氮唑分子的引入，確實大幅提升發光元件之亮度及效率。以上結果說明該材料具有應用於發光元件之潛力。

The goal of this research is to synthesize soluble triazole derivative (BEHP-TAZ), to study its optical, electrochemical, and thermal properties, and to evaluate the performance of this material in triple-layer light-emitting devices. The principle of molecular design is introducing branched alkoxy chains on both ends to improve solubility of the material, and incorporating benzene ring to separate triazole center core from chain ends. The conjugation length is also elongated. The result from differential scanning calorimetry reveals that its glass transition tempeature is at 84 oC. The maximum UV-visible absorption and fluorescence emission wavelengths of the material in film state are located at 310 and 399 nm, respectively. The results obtained from cyclic voltammetric analysis and absorption spectrum show that the highest-occupied molecular orbital, lowest-unoccupied molecular orbital, and bandgap of the material are -5.86, -2.64, and 3.22 eV, respectively. Finaly, triple-layer light-emitting devices with configuration of ITO/PEDOT/Polymer/BEHP-TAZ/Al were fabricated and compared with double-layer devices, where soluble triazole molecule BEHP-TAZ was used as electron transporting layer, MEH-PPV or PFO as emissive layer. The experimental result demonstrates that the incorporation of soluble triazole molecule BEHP-TAZ brings significant enhanchent in brightness and efficiency of the devices, indicating its potential application in light-emitting devices.