Synthesis and characterization of 2,1,3-benzothiadiazole-thieno[3,2-b]thiophene-based charge transferred-type polymers for photovoltaic application

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• 作者：Jang Yong Lee ; Soo Won Heo ; Heelack Choi ; Yoon Jung Kwon ; Jung Rim Haw ; Doo Kyung Moon
• 关键词：Organic photovoltaics ; Donor materials ; Bulk heterojunction ; Thieno[3 ; 2-b]thiophene ; 2 ; 1 ; 3-benzothiadiazole
• 刊名：Solar Energy Materials and Solar Cells
• 出版年：2009
• 出版时间：November 2009
• 年：2009
• 卷：93
• 期：11
• 页码：1932-1938
• 全文大小：318 K

文摘

New low-band-gap copolymers, including thieno[3,2-b]thiophene and 2,1,3-benzothiadiazole, were synthesized as photovoltaic materials. Thiophene was introduced to provide extended π-conjugation length and charge transfer properties. A band gap (E_g^op=1.62 eV, E_g^ec=1.51 eV) of this polymer was investigated through UV–vis spectroscopy and cyclic voltammetry. A bulk heterojunction structure of glass/indium tin oxide (ITO)/PEDOT:PSS/polymer-PCBM(1:3)/LiF/Al was fabricated for investigating photovoltaic properties. PC₇₁BM was used as an acceptor material, due to its increased absorption in the visible region, in comparison with PC₆₁BM. In this polymer, incident photon-to-current conversion efficiency (IPCE) was as high as 50 % . Moreover, maximum power conversion efficiency (PCE) of up to 1.72 % was achieved under AM 1.5 G conditions. It demonstrated relatively high V_OC (0.67 V) and J_SC (6.86 mA/cm²), while a low fill factor value (0.37) was obtained.