Efficient Polymer Solar Cells with Surface Relief Gratings Fabricated by Simple Soft Lithography

Authors

  • Seok-In Na,

    1. Heeger Center for Advanced Materials Department of Materials Science and Engineering Gwangju Institute of Science and Technology 1 Oryong-Dong, Buk-Gu, Gwangju 500-712 (Korea)
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  • Seok-Soon Kim,

    1. School of Materials Science and Chemical Engineering Kunsan National University Kunsan, Chonbuk, 573-701 (Korea)
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  • Jang Jo,

    1. Heeger Center for Advanced Materials Department of Materials Science and Engineering Gwangju Institute of Science and Technology 1 Oryong-Dong, Buk-Gu, Gwangju 500-712 (Korea)
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  • Seung-Hwan Oh,

    1. Heeger Center for Advanced Materials Department of Materials Science and Engineering Gwangju Institute of Science and Technology 1 Oryong-Dong, Buk-Gu, Gwangju 500-712 (Korea)
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  • Juhwan Kim,

    1. Heeger Center for Advanced Materials Department of Materials Science and Engineering Gwangju Institute of Science and Technology 1 Oryong-Dong, Buk-Gu, Gwangju 500-712 (Korea)
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  • Dong-Yu Kim

    Corresponding author
    1. Heeger Center for Advanced Materials Department of Materials Science and Engineering Gwangju Institute of Science and Technology 1 Oryong-Dong, Buk-Gu, Gwangju 500-712 (Korea)
    • Heeger Center for Advanced Materials Department of Materials Science and Engineering Gwangju Institute of Science and Technology 1 Oryong-Dong, Buk-Gu, Gwangju 500-712 (Korea).
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  • This work was financially supported by the Heeger Center for Advanced Materials (HCAM), the Ministry of Education of Korea through the Brain Korea 21 (BK21) program, the Korea Science and Engineering Foundation (KOSEF) through the National Research Lab Program funded by the Korean government (MEST) (M10500000077-06J0000-07710).

Abstract

Polymer-based photovoltaic cells, with periodic sub-micrometer structures as an efficient light-trapping scheme, are investigated to improve the performance of organic solar cells based on poly(3-hexylthiophene) and 1-(3-methoxycarbonyl)propyl-1-phenyl-(6,6)C61. A soft lithographic approach that uses photoresponsive azo polymer films as masters and poly(dimethylsiloxane) as stamps is used to form surface relief gratings (SRGs) on the active layers. The effect of periodic gratings on solar cell performance is precisely investigated according to various grating conditions such as period, depth, and dimension. The solar cells with 1D and 2D SRGs present improved incident-photon-to-current conversion efficiencies and an overall increase in power conversion efficiencies, primarily resulting from the enhancement of short-circuit current density, indicating that periodic structures induce further photon absorption in the active film.

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