Efficiency Enhancement of Organic Solar Cells by Using Shape-Dependent Broadband Plasmonic Absorption in Metallic Nanoparticles

Authors

  • Xuanhua Li,

    1. Department of Electrical and Electronic Engineering, the University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
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  • Wallace Chik Ho Choy,

    Corresponding author
    1. Department of Electrical and Electronic Engineering, the University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
    • Department of Electrical and Electronic Engineering, the University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China.
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  • Haifei Lu,

    1. Department of Electronic Engineering, Center for Advanced Research in Photonics, the Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, 852, P. R. China
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  • Wei E. I. Sha,

    1. Department of Electrical and Electronic Engineering, the University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
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  • Aaron Ho Pui Ho

    1. Department of Electronic Engineering, Center for Advanced Research in Photonics, the Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, 852, P. R. China
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Abstract

It is been widely reported that plasmonic effects in metallic nanomaterials can enhance light trapping in organix solar cells (OSCs). However, typical nanoparticles (NP) of high quality (i.e., mono-dispersive) only possess a single resonant absorption peak, which inevitably limits the power conversion efficiency (PCE) enhancement to a narrow spectral range. Broadband plasmonic absorption is obviously highly desirable. In this paper, a combination of Ag nanomaterials of different shapes, including nanoparticles and nanoprisms, is proposed for this purpose. The nanomaterials are synthesized using a simple wet chemical method. Theoretical and experimental studies show that the origin of the observed PCE enhancement is the simultaneous excitation of many plasmonic low- and high-order resonances modes, which are material-, shape-, size-, and polarization-dependent. Particularly for the Ag nanoprisms studied here, the high-order resonances result in higher contribution than low-order resonances to the absorption enhancement of OSCs through an improved overlap with the active material absorption spectrum. With the incorporation of the mixed nanomaterials into the active layer, a wide-band absorption improvement is demonstrated and the short-circuit photocurrent density (Jsc) improves by 17.91%. Finally, PCE is enhanced by 19.44% as compared to pre-optimized control OSCs. These results suggest a new approach to achieve higher overall enhancement through improving broadband absorption.

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