3D‐printed external light trap for solar cells. (26th November 2015)

• Record Type: Journal Article
• Authors: Dijk, Lourens van; Paetzold, Ulrich W.; Blab, Gerhard A.; Schropp, Ruud E. I.; di Vece, Marcel
• Is Part Of: Progress in photovoltaics. Volume 24:Number 5(2016)
• Page Start: 623
• Page End: 633
• Publication Date: 2015-11-26
• Subjects: thin‐film solar cells -- external light trapping -- 3D printing -- anti‐reflection -- compound parabolic concentrator (CPC); Solar cells -- Periodicals; Photovoltaic cells -- Periodicals; Solar power plants -- Periodicals; 621.31245
• DOI: 10.1002/pip.2702
• Languages: English
• ISSNs: 1062-7995

Abstract

Abstract: We present a universally applicable 3D‐printed external light trap for enhanced absorption in solar cells. The macroscopic external light trap is placed at the sun‐facing surface of the solar cell and retro‐reflects the light that would otherwise escape. The light trap consists of a reflective parabolic concentrator placed on top of a reflective cage. Upon placement of the light trap, an improvement of 15% of both the photocurrent and the power conversion efficiency in a thin‐film nanocrystalline silicon (nc‐Si:H) solar cell is measured. The trapped light traverses the solar cell several times within the reflective cage thereby increasing the total absorption in the cell. Consequently, the trap reduces optical losses and enhances the absorption over the entire spectrum. The components of the light trap are 3D printed and made of smoothened, silver‐coated thermoplastic. In contrast to conventional light trapping methods, external light trapping leaves the material quality and the electrical properties of the solar cell unaffected. To explain the theoretical operation of the external light trap, we introduce a model that predicts the absorption enhancement in the solar cell by the external light trap. The corresponding calculated path length enhancement shows good agreement with the empirically derived value from the opto‐electrical data of the solar cell. Moreover, we analyze the influence of the angle of incidence on the parasitic absorptance to obtain full understanding of the trap performance. © 2015 The Authors. Progress in Photovoltaics: Research and Applications published by John Wiley & Sons, Ltd. Abstract : We demonstrate a universally applicable 3D‐printed external light trap for enhanced solar cell efficiency. The trapped light traverses the solar cell several times within the reflective cage, and due to this path length enhancement, the absorption in the cell increases. In contrast to conventional light trapping methods, external light trapping leaves the electrical properties of the cell unaffected. The 3D‐printed external light trap improved the power conversion efficiency of a thin‐film nanocrystalline silicon (nc‐Si:H) solar cell by 15%.