Organic D-A-π-A Solar Cell Sensitizers with Improved Stability and Spectral Response

Authors

  • Weihong Zhu,

    1. Key Laboratory for Advanced Materials and Institute of Fine, Chemicals, East China University of Science and Technology, Shanghai 200237, PR China, Fax: (+86) 21–6425-2758
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  • Yongzhen Wu,

    1. Key Laboratory for Advanced Materials and Institute of Fine, Chemicals, East China University of Science and Technology, Shanghai 200237, PR China, Fax: (+86) 21–6425-2758
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  • Shutao Wang,

    1. Department of Chemistry & Laboratory of Advanced Materials, Fudan University, Shanghai 200433, PR China
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  • Wenqin Li,

    1. Key Laboratory for Advanced Materials and Institute of Fine, Chemicals, East China University of Science and Technology, Shanghai 200237, PR China, Fax: (+86) 21–6425-2758
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  • Xin Li,

    1. Key Laboratory for Advanced Materials and Institute of Fine, Chemicals, East China University of Science and Technology, Shanghai 200237, PR China, Fax: (+86) 21–6425-2758
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  • Jian Chen,

    1. Key Laboratory for Advanced Materials and Institute of Fine, Chemicals, East China University of Science and Technology, Shanghai 200237, PR China, Fax: (+86) 21–6425-2758
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  • Zhong-sheng Wang,

    Corresponding author
    1. Department of Chemistry & Laboratory of Advanced Materials, Fudan University, Shanghai 200433, PR China
    • Department of Chemistry & Laboratory of Advanced Materials, Fudan University, Shanghai 200433, PR China.
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  • He Tian

    Corresponding author
    1. Key Laboratory for Advanced Materials and Institute of Fine, Chemicals, East China University of Science and Technology, Shanghai 200237, PR China, Fax: (+86) 21–6425-2758
    • Key Laboratory for Advanced Materials and Institute of Fine, Chemicals, East China University of Science and Technology, Shanghai 200237, PR China, Fax: (+86) 21–6425-2758
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Abstract

A novel concept “D-A-π-A” organic sensitizer instead of traditional D-π-A ones is proposed. Remarkably, the incorporated low bandgap, strong electron-withdrawing unit of benzothiadiazole shows several favorable characteristics in the areas of light-harvesting and efficiency: i) optimized energy levels, resulting in a large responsive range of wavelengths into NIR region; ii) a very small blue-shift in the absorption peak on thin TiO2 films with respect to that in solution; iii) an improvement in the electron distribution of the donor unit to distinctly increase the photo-stability of synthetic intermediates and final sensitizers. The stability and spectral response of indoline dye-based DSSCs are improved by the strong electron-withdrawing benzothiadizole unit in the conjugation bridge. The incident-photon-conversion efficiency of WS-2 reaches nearly 850 nm with a power conversion efficiency as high as 8.7% in liquid electrolyte and 6.6% in ionic-liquid electrolyte.

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