| 摘要: | 摘要 導電高分子在現今最受矚目的應用之一是在顯示器科技上，而其中，聚塞吩衍生物在此项應用中是佔有一席之地的，因其結構的多變性與良好的環境穩定性，能有效的經過改變高分子主鏈或支鏈的結構來調整其EL放光光色與量子產率。文獻報導中指出，聚塞吩加入長碳鏈烷基雖可增加其溶解度但同時也會影響其量子產率與放光光色。本實驗便是在以不失溶解度的前提下，合成出一系列不同側鏈基密度的聚塞吩衍生物，包括有poly (3-octylthiophene)簡稱(POTH)、Poly(3,3"-dioctyl- 2,2'; 5',2"-terthiophene) (POTTOT)、Poly(3'-octyl-2,2'- bithiophene) (POTT)Poly (3-octyl- 2,2';5',2"-terthiophene) (PTOTT)等發光高分子，並將其製成單層PLED來探討高分子側鏈基密度對發光效率的影響。實驗結果顯示具有較低側鏈基密度的高分子也相對的有較高的量子產率，對PLED發光效率而言，由於尚需考慮元件製程等其它因素故無法直接找到關聯性。另外為了提升聚塞吩本身不佳的量子產率，在主鏈中加入結構剛硬且量子產率高的Pyridine環，合成出Poly(2,6-Bis-(3-octyl-thiophene-2yl)-pyridine) (POTPyOT)與Poly(2-(3-octyl-thiophene-2-yl)-pyridine) (POTPy) 此類高分子除放光波長有明顯的藍位移外螢光效率也好很多。在相同條件下由POTPyOT為發光層所製得之PLED元件比以POTPy為發光層的穩定而且發光效率高，我們將從高分子薄膜之帶結構(Band structure)與表面型態來探討除高分子本身的性質外影響元件功能因素。 Abstract As a class of conjugated polymers with a great potential for the new generation display technology, polythiophene and its derivatives play an important role. The diversity of the structure, good environmental stability, as well as interesting physical and chemical properties made polythiophenes as one of the extensively studied conjugated polymers in the past two decades. It was found that adding alkyl side chain into polymer backbone can increase the solubility nevertheless, at the same time decreases its quantum efficiencies, due to the mobility of alkyl chain. To understand the effect of the side chain on the quantum efficiencies, a series of poly3-alkylthiophene derivatives with various side chain density [such as Poly(3-octylthiophene) (POTH)、Poly(3,3’-dioctyl-2,2’;5’,2’ -terthio-phene) (POTTOT)、Poly(3’-octyl-2,2’-bithiophene) (POTT)、Poly(3-octyl-2, 2’;5’,2’’-terthiophene) (PTOTT)] were synthesized and use them to be emitting layer in Polymer Light-emitting diode. We found that polymer with lower side-chain density has a higher PL quantum yield. However, there is no relationship between EL efficiency with side chain density due to the complicated device fabrication process. To increase the quantum efficiency, polyalkylthiophene derivatives with a rigid pyridine ring in the main chain such as Poly(2,6-Bis-(3-ocytlthiophene-2yl) -pyridine) (POTPyOT) and Poly(2-(3-octylthiophene-2-yl)-pyridine) (POTPy) were prepared. The luminescence studies showed that the pyridine ring in polymer backbone not only caused the blue-shift of the emission light but also enhanced the quantum yield significantly. The synthetic approaches and structure related photoluminescence and electroluminescence of the polymers were illustrated. II |
