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

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 mu m 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/cm(2), 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/cm(2) by incorporating a back-reflector and improved antireflection, for which we estimate a photovoltaic efficiency above 21% for 1 mu m thick Si cells.

Automated summary

This study presents a new surface texturing technique for improving the absorption and efficiency of thin crystalline silicon solar cells. By using hyperuniform nanostructuring, it achieves a high solar light absorption of 66.5% in the spectral range of 400 to 1050 nm. This technology has the potential to increase the cell efficiency to above 15%.