近年來利用調控不同溶劑性質來引導聚(3-己基噻吩)(poly(3-hexylthiophene) , P3HT)在溶液中結晶受到廣大的關注，比起單純利用溶劑退火或是熱退火等後處理，此方法有利於大量製造結晶度較高的奈米纖維。由於良好的有機元件的性質通常取決於良好的結構，探究其溶劑性質對於結構的影響有其必要。 本文主要聚焦於聚P3HT在數種不同性質的稀薄溶液中的結構變化，利用三種對於主鏈支鏈親好性不同的良溶劑；THF親好主鏈的噻吩、而討厭支鏈的n-己基、環己烷的親好性與THF相反而甲苯介於兩者之間。再透過添加適量的醇類，組成雙成份混合溶劑可自由調控其聚集驅動力。經由激子耦合分析不同溶劑在一定熟化時間下的UV-vis光譜，我們發現貧溶劑的添加主要影響P3HT聚集速率的快慢，而對於P3HT在貧溶劑種類溶液中，最鄰近分子間庫倫耦合能J0變化不劇烈；J0主要受到混摻比例與良溶劑種類的影響而改變。 在THF系統中，溶液很快的形成較大尺度的團聚結構，但其奈米纖維呈散亂排列故不適合作為製程溶劑。在甲苯中形成單一而獨立的奈米纖維，除了與1-丙醇混摻的甲苯混合溶劑，其餘溶劑對對於奈米纖維的穩定定高，長時間熟化下仍不會形成大尺度的團聚結構。而環己烷系統在平衡下團聚物所占的比例比其他兩種溶劑高，且除了一維方向的π-π堆疊外，還會形成二維方向的排列片狀團聚。 ;Organic devices have attracted great interests due to their advantages of low cost, solution-based processes, and flexibility. Poly(3-hexylthiophene)(P3HT), as a typical linear conjugated polymer, have been applied in commercial processes. In this study, we focused on the conformation of P3HT chains in three organic solvents of different selectivity. The chain conformation in the dilute solutions affected the morphology in solid state. By controlling the composition of binary co-solvent mixtures, the drive force of P3HT aggregation can be finely tuned. THF is a good solvent for the thiophene backbone and but a poor one for the 3-hexyl side chain. In contrast, the affinity of cyclohexane shows an opposite trend, being good for 3-hexyl side chains but poor for the thiophene backbone. The selectivity of toluene lies between THF and cyclohexane. Next I added a series of alcohols with different CH2 length to tune the solvent quality to form P3HT aggregates with different nanostructures in solutions. UV-vis and PL measurements were used to identify the correlations between solvent quality and the degree of ordering in aggregates. AFM and GIWAXD characterizations were carried out to investigate the P3HT morphology and the degree of crystallization in solid state. As the polarization of alcohols increased, the aging rate increased. the nearest-neighbor inter-chain coulombic coupling J0 did not significantly change. J0 is sensitive to the selectivity of solvents and the ratios of alcohols in binary co-solvent mixtures. P3HT aged quickly in the solvent mixture of THF/alcohols and formed large-sized aggregation structures with disorder orientation. In the solvent mixtures of toluene/ alcohols (except for toluene/1-propanol), P3HT formed single fibers and well dispersed. In contrast, P3HT in the cosolvent mixtures of cyclohexane/alcohols was found to form bundles of nano-sized fibers with high orientational ordering.
