Photo-Carrier Recombination in Polymer Solar Cells Based on P3HT and Silole-Based Copolymer

Authors

  • Song Chen,

    1. Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611-6400, USA
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  • Kaushik Roy Choudhury,

    1. Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611-6400, USA
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  • Jegadesan Subbiah,

    1. Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611-6400, USA
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  • Chad M. Amb,

    1. The George and Josephine Butler Polymer Research Laboratory, Department of Chemistry, Center for Macromolecular Science and Engineering, University of Florida, Gainesville, Florida 32611, USA
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  • John R. Reynolds,

    Corresponding author
    1. The George and Josephine Butler Polymer Research Laboratory, Department of Chemistry, Center for Macromolecular Science and Engineering, University of Florida, Gainesville, Florida 32611, USA
    • The George and Josephine Butler Polymer Research Laboratory, Department of Chemistry, Center for Macromolecular Science and Engineering, University of Florida, Gainesville, Florida 32611, USA
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  • Franky So

    Corresponding author
    1. Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611-6400, USA
    • Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611-6400, USA.
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Abstract

Photo-current loss in donor-acceptor (DA) polymer-fullerene bulk heterojunction solar cells was studied via carrier transport and recombination measurements. Focusing on the DA polymer poly((4,4-dioctyldithieno (3,2-b:2',3'-d) silole)-2,6-diyl-alt-(2,1,3-benzothiadiazole)-4,7-diyl) (DTS-BTD) we found that the carrier transport is well-balanced and attribute the loss mechanism in DTS-BTD solar cells to carrier recombination. Using carrier extraction with linear increasing voltage (photo-CELIV) and transient photo-voltage (TPV), we show that carrier recombination plays an important role in photo-current extraction at open circuit conditions due to increase in photo-excited carrier concentration. Delay time dependent photo-CELIV and temperature dependent transport studies suggest that the recombination rate is related to the degree of energetic disorder in the polymer: fullerene blends.

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