含噻吩并[3,4-c]吡咯-4 ,6 -二酮之施體–受體型共軛高分子的合成與性質分析及其太陽能電池之研究

Abstract

本論文中合成了含拉電子基團thieno[3,4-c]pyrrole-4,6-dione (TPD) 與推電子單元bi(alkyl)thiophene 之PBTTPD 系列高分子; 並以TPD 基團分別與共平面性之推電子單元cyclopenta[2,1-b;3,4-b′]dithiophene (CPDT）及dithieno[3,2-b:2′,3′-d]silole (DTS) 共聚，合成具低光學能隙之PCPDTTPD 及PDTSTPD 高分子。 PBTTPD 系列高分子具高結晶性、低HOMO 能階、高熱穩定度等性質。 將此系列高分子與 [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) 混掺製成塊狀異質介面太陽能電池元件，皆具不錯之元件特性，其中PBTTPD1之元件光電轉換效率可達4.7 %。而PDTSTPD 與PCPDTTPD 兩高分子皆具低光學能隙及高熱穩定性等性質， 將此兩高分子分別與[6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) 混掺製成塊狀異質介面太陽能電池元件，其能量轉換效率分別為1.0 % 與1.6 %，且於加入微量添加劑後可使表面形貌更加均勻，使其能量轉換效率可分別提升至3.1 % 與2.7 %。

In this thesis, a series of donor-acceptor (D–A) conjugated polymers, PBTTPDs, containing electron-withdrawing thieno[3,4-c]pyrrole-4,6-dione (TPD) and electron-donating bi(alkyl)thiophene units were synthesized. We also prepared two TPD based low band-gap polymers, PCPDTTPD and PDTSTPD, conatining electron-donating cyclopenta[2,1-b;3,4-b′]dithiophene (CPDT) and dithieno[3,2-b:2′,3′-d]silole (DTS) units. The PBTTPD based polymers exhibit high crystalline characteristics, low-lying HOMO energy level, and excellent thermal properties. Bulk heterojunction (BHJ) photovoltaic devices incorporating these polymers/ [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) blend displayed good photovoltaic properties. Especially, the PBTTPD1 based device displayed a high power conversion efficiency (PCE) of 4.7%. Moreover, both of PCPDTTPD and PDTSTPD exhibit low band-gap properties (1.74 and 1.69 eV, respectively) and excellent thermal properties. BHJ photovoltaic devices incorporating PCPDTTPD/[6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) and PDTSTPD/PC71BM blends displayed PCEs of 1.0% and 1.6%, respectively. Furthermore, when incorporating small amount of additives into these blends, their PCEs of devices were enhanced to 3.1% and 2.7%, individually, because of their smoother and more homogeneous morphology of the blend.