Over 65% Sunlight Absorption in a 1 μm Si Slab with Hyperuniform Texture

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Publication date
DOI http://dx.doi.org/10.1021/acsphotonics.1c01668
Reference N. Tavakoli, R. Spalding, A. Lambertz, P. Koppejan, G. Gkantzounis, C. Wan, R. Röhrich, E. Kontoleta, A.F. Koenderink, R. Sapienza, M. Florescu and E. Alarcón-Lladó, Over 65% Sunlight Absorption in a 1 μm Si Slab with Hyperuniform Texture, ACS Photonics 9, (4), 1206-1217 (2022)
Groups 3D Photovoltaics, Nanoscale Solar Cells, Resonant Nanophotonics

Thin, flexible, and invisible solar cells will be a ubiquitous technology in the near future. Ultrathin crystalline silicon (c-Si) cells capitalize on the success of bulk silicon cells while being lightweight and mechanically flexible, but suffer from poor absorption and efficiency. Here we present a new family of surface texturing, based on correlated disordered hyperuniform patterns, capable of efficiently coupling the incident spectrum into the silicon slab optical modes. We experimentally demonstrate 66.5% solar light absorption in free-standing 1 μm c-Si layers by hyperuniform nanostructuring for the spectral range of 400 to 1050 nm. The absorption equivalent photocurrent derived from our measurements is 26.3 mA/cm2, which is far above the highest found in literature for Si of similar thickness. Considering state-of-the-art Si PV technologies, we estimate that the enhanced light trapping can result in a cell efficiency above 15%. The light absorption can potentially be increased up to 33.8 mA/cm2 by incorporating a back-reflector and improved antireflection, for which we estimate a photovoltaic efficiency above 21% for 1 μm thick Si cells.