末端修飾聚三-己烷噻吩高分子之合成、自組裝調控與其在太陽電池之應用

Abstract

有機太陽能電池（Organic Photovoltaics，OPV）為以有機化合物作為太陽能電池的材料，符合低價格且製程簡易的優點。本論之研究目的在於合成新穎聚噻吩高分子，利用其高分子之特性製作成元件。 第一部份為聚噻吩鏈段共聚物之合成與光電性質研究，本研究之高分子的構思源自於 Ho, R. M. et al.將polystyrene-block-poly(l-lactide) (PS-PLLA) 的鏈段共聚物製作成具有自組裝現象的高分子薄膜。並經由精確的分子量控制和去除乳酸片段，製作成具有孔洞的高分子材料。在鏈段共聚物的合成部份，以poly(3-hexyl- thiophene) (P3HT)取代PS，並藉由末端修飾的格林納置換聚合反應和配位插入開環聚合反應的合成方法合成出poly(3-hexylthiophene)- block-poly(l-lactide) (P3HT-PLLA)的鏈段聚合物，並利用基質輔助激光解析飛行時間質譜（MALDI-TOF MS）做末端官能基的分析並對照1H NMR的圖譜來鑑定高分子。此外，針對P3HT及PLLA片段進行不同分子量的合成。在太陽能電池元件製作部分，將此具有相分離特性的薄膜應用至元件活化層，接著將PLLA片段以溫和的方式裂解後，可得到具奈米孔洞結構的P3HT活化層。本研究期望能夠結合具吸光性質的太陽能電池材料及特殊的奈米孔洞形態兩項特性，進而增加與電子接受體的接觸面積，有效達到電荷分離效果。 第二部份為結合多面體矽氧烷寡聚物(POSS)，將末端修飾雙鍵的聚噻吩高分子與POSS連接製作成星狀結構之材料。由於矽氧烷具有相當好的熱穩定性，本研究期望藉由此特性改善元件的熱穩定性。此外，由於分子量的增加，可以有效改善高分子的成膜性，使得元件的效率得以提升。

Organic Photovoltaics (OPVs) have several advantages such as flexible, easy fabrication and low cost. The goal of this research is to study the synthesis and application of new poly(3-hexylthiophene) derivatives. The first part of this study is to incorporate poly(3-hexylthiophene) (P3HT) into copolymer structure with poly(l-lactide) (PLLA) blocks via a feasible Grignard metathesis method to control the end-capping group, and ring-opening polymerization method to combine the l-lactide monomer. Different volume fractions of P3HT-PLLA were prepared with different molecular weight of PLLA. The chemical structure of the copolymers were investigated by 1HNMR and MALDI-TOF MS. Well-defined and phase-separated microdomains of P3HT-PLLA thin film can be observed by appropriate solvents and post-thermal treatment. The block copolymer films reveal pit-like surface morphology. After degradation of PLLA block, the films with large amounts of porous texture were formed and used as templates for the fabrication of organic solar cells. The OPV devices with P3HT nanoporous film show higher power conversion efficiency than that with pristine P3HT thin film. The second part of this study, we combined vinyl terminated poly(3-hexylthiophene) with 1,3,5,7,9,11,13,15-Octakis(dimethylsilyloxy)- pentacyclo[9.5.1.13,9.15,15.17,13]octasiloxane to synthesized new star-like P3HT polymer. This star-like polymer shows better film forming property and better device stability than the original vinyl-terminated P3HT.