Synthesis and Search for Design Principles of New Electron Accepting Polymers for All-Polymer Solar Cells

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• 作者：In Hwan Jung ; Wai-Yip Lo ; Jaeyoung Jang ; Wei Chen ; Donglin Zhao ; Erik S. Landry ; Luyao Lu ; Dmitri V. Talapin ; Luping Yu
• 刊名：Chemistry of Materials
• 出版年：2014
• 出版时间：June 10, 2014
• 年：2014
• 卷：26
• 期：11
• 页码：3450-3459
• 全文大小：518K
• 年卷期：v.26,no.11(June 10, 2014)
• ISSN：1520-5002

文摘

New electron withdrawing monomers, thieno[2鈥?3鈥?5鈥?6鈥瞉pyrido[3,4-g]thieno[3,2-c]isoquinoline-5,11(4H,10H)-dione (TPTI) and fluorenedicyclopentathiophene dimalononitrile (CN), have been developed and used to form 12 alternating polymers having different monomer combinations: (a) weak donating monomer鈥搒trong accepting monomer, (b) weak accepting monomer鈥搒trong accepting monomer, (c) weak accepting monomer鈥搘eak accepting monomer, and (d) strong donating monomer鈥搒trong accepting monomer. It was found that lowest unoccupied molecular orbital (LUMO) energy levels of polymers are significantly determined by stronger electron accepting monomers and highest occupied molecular orbital (HOMO) energy levels by the weak electron accepting monomers. In addition, fluorescent quantum yields of the TPTI-based polymers in chloroform solution are significantly decreased as the LUMO energy levels of the TPTI series of polymers become deeper. The quantum yield was found to be closely related with the photovoltaic properties, which reflects the effect of internal polarization on the photovoltaic properties. Only the electron accepting polymers showing SCLC mobility higher than 10^鈥? cm²/(V s) exhibited photovoltaic performance in blend films with a donor polymer, and the PTB7:PNPDI (1:1.8 w/w) device exhibited the highest power conversion efficiency of 1.03% (V_oc = 0.69 V, J_sc = 鈭?.13 mA/cm², FF = 0.36) under AM 1.5G condition, 100 W/cm². We provide a large set of systematic structure鈥損roperty relationships, which gives new perspectives for the design of electron accepting materials.