Enhanced absorption of thin-film photovoltaic cells using an optical cavity


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Weinstein L. A. , HSU W., Yerci S., Boriskina S. V. , CHEN G.

JOURNAL OF OPTICS, vol.17, no.5, 2015 (Peer-Reviewed Journal) identifier identifier

  • Publication Type: Article / Article
  • Volume: 17 Issue: 5
  • Publication Date: 2015
  • Doi Number: 10.1088/2040-8978/17/5/055901
  • Journal Name: JOURNAL OF OPTICS
  • Journal Indexes: Science Citation Index Expanded, Scopus
  • Keywords: photovoltaics, light trapping, ray tracing, SOLAR-CELLS, FUNDAMENTAL LIMIT, PERFORMANCE, EFFICIENCY, COST

Abstract

We show via numerical simulations that the absorption and solar energy conversion efficiency of a thin-film photovoltaic (PV) cell can be significantly enhanced by embedding it into an optical cavity. A reflective hemi-ellipsoid with an aperture for sunlight placed over a tilted PV cell reflects unabsorbed photons back to the cell, allowing for multiple opportunities for absorption. Ray tracing simulations predict that with the proposed cavity a textured thin-film silicon cell can exceed the Yablonovitch (Lambertian) limit for absorption across a broad wavelength range, while the performance of the cavity-embedded planar PV cell approaches that of the cell with the surface texturing.