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Design of a New Energy-Harvesting Electrochromic Window Based on an Organic Polymeric Dye, a Cobalt Couple, and PProDOT-Me2

Authors

  • Eri Amasawa,

    1. Center for Intelligent Materials and Systems, Mechanical Engineering Department, University of Washington, Seattle, WA, USA
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    • Present address: Graduate Program on Sustainability Science, Graduate School of Frontier Science, The University of Tokyo, Kashiwanoha, Chiba, 277-8563, Japan

  • Naoki Sasagawa,

    1. Division of Chemistry and Materials, Faculty of Textile Science and Technology, Shinshu University, Ueda, Nagano, Japan
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  • Mutsumi Kimura,

    1. Division of Chemistry and Materials, Faculty of Textile Science and Technology, Shinshu University, Ueda, Nagano, Japan
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  • Minoru Taya

    Corresponding author
    1. Center for Intelligent Materials and Systems, Mechanical Engineering Department, University of Washington, Seattle, WA, USA
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Abstract

A new design for an energy-harvesting electrochromic window (EH-ECW) based on the fusion of two technologies, organic electrochromic windows and dye-sensitized solar cells (DSSCs), is presented. Unlike other power-generating smart windows, such as photoelectrochromic devices that are passive and only contain two states (i.e., a closed-circuit colored state and an open-circuit bleaching state), EH-ECW allows active tuning of the transmittance by varying the applied potential and it functions as a photovoltaic cell based on a DSSC. The resulting device demonstrates a fast switching rate of 1 s in both the bleaching and coloring processes through the use of an electrochromic polymer as a counter electrode layer. To increase the transmittance of the device, a cobalt redox couple and a light-colored, yet efficient, organic dye are used. The organic dye contains a polymeric structure that contributes to the high cyclic stability. The device exhibits a power conversion efficiency (PCE) of 4.5% (100 mW cm-2) under AM 1.5 irradiation, a change in transmittance of 34% upon applied potential, and shows only 3% degradation in the PCE after 5000 cycles.

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