Developing Wide Bandgap Polymers Based on Sole Benzodithiophene Units for Efficient Polymer Solar Cells |
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Authors: | Dr Xiaopeng Xu Dr Young Woong Lee Prof Han Young Woo Prof Ying Li Prof Qiang Peng |
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Institution: | 1. Key Laboratory of Green Chemistry and Technology of Ministry of, Education, College of Chemistry, State Key Laboratory of, Polymer Materials Engineering, Sichuan University, Chengdu, 610064 P. R. China
These authors contributed equally to this work.;2. Department of Chemistry, Korea University, Seoul, 136-713 Republic of Korea
These authors contributed equally to this work.;3. Department of Chemistry, Korea University, Seoul, 136-713 Republic of Korea;4. Key Laboratory of Green Chemistry and Technology of Ministry of, Education, College of Chemistry, State Key Laboratory of, Polymer Materials Engineering, Sichuan University, Chengdu, 610064 P. R. China |
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Abstract: | In this work, a series of sole benzodithiophene-based wide band gap polymer donors, namely PBDTT, PBDTS, PBDTF and PBDTCl, were developed for efficient polymer solar cells (PSCs) by varying the heteroatoms into the conjugated side chains. The effects of sulfuration, fluorination and chlorination were also investigated systematically on the overall properties of these BDT-based polymers. The HOMO levels could be lowered gradually by introducing sulfur, fluorine and chlorine atoms into the side chains, which contributed to the stepwise increased Voc (from 0.78 V to 0.84 V) in the related PSCs using Y6 as the electron acceptor. This side-chain engineering strategy could promote the polymer chain interactions and fine-tune the phase separation of active blends, leading to enhanced absorption, ordered molecular packing and crystallinity. Among them, the chlorinated PBDTCl exhibited not only high level absorption and crystallinity, but also the most balanced hole/electron charge transport and the most optimized morphology, giving rise to the best PCE of 13.46 % with a Voc of 0.84 V, a Jsc of 23.16 mA cm−2 and an FF of 69.2 %. The chlorination strategy afforded PBDTCl synthetic simplicity but high efficiency, showing its promising photovoltaic applications for realizing low-cost practical PSCs in near future. |
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Keywords: | energy conversion photovoltaics polymer solar cells sole donor unit synthetic simplicity |
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