標題: Thiophene spacers impart crystallinity and enhance the efficiency of benzotrithiophene-based conjugated polymers for bulk heterojunction photovoltaics
作者: Lan, Shang-Che
Yang, Po-An
Zhu, Meng-Jie
Yu, Chia-Min
Jiang, Jian-Ming
Wei, Kung-Hwa
材料科學與工程學系
Department of Materials Science and Engineering
公開日期: 2013
摘要: In this study we synthesized the donor-acceptor conjugated copolymers PBTT4BT and PBTT4BO featuring benzotrithiophene (BTT) units as donors and benzothiadiazole (BT) and benzoxadiazole (BO) units, respectively, as acceptors, linked through 4-dodecylthiophene spacers. The presence of the spacer units enhanced not only the solubility of the synthesized polymers but also their molecular packing in the solid state; both of these polymers exhibited good crystallinity, as evidenced by a d-spacing of 23.8 angstrom in the (100) plane in their X-ray diffraction curves. When we used these synthesized polymers in bulk heterojunction photovoltaic device applications, the optimal device incorporating PBTT4BO/PC61BM as the active layer exhibited a low efficiency of 3.2%, due to the poor solubility of PBTT4BO, whereas the optimal device incorporating the more-soluble PBTT4BT and PC71BM displayed an efficiency of 4.4%, which is substantially 1.5% higher than that for the PBTTBT/PC71BM device, where PBTTBT was formed by copolymerizing BTT and BT units without any spacer. After thermal annealing, the efficiency of the PBTT4BT/PC71BM device improved further to 5.6%, with a V-OC value of 0.72 V, a J(SC) value of 11.58 mA cm(-2) and a fill factor of 67%. The annealed PBTT4BT/PC71BM active layer possessed a nanoscaled network-like morphology with rod-like PBTT4BT domains that were beneficial for charge separation and transport; accordingly, the power conversion efficiency of the annealed PBTT4BT/PC71BM photovoltaic device was enhanced greatly over that of the as-cast PBTT4BT/PC71BM device.
URI: http://hdl.handle.net/11536/21080
http://dx.doi.org/10.1039/c2py20819a
ISSN: 1759-9954
DOI: 10.1039/c2py20819a
期刊: POLYMER CHEMISTRY
Volume: 4
Issue: 4
起始頁: 1132
結束頁: 1140
顯示於類別:期刊論文


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  1. 000313807200034.pdf