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

Area of Science:

• Materials Science
• Nanotechnology
• Photovoltaics

Background:

• Ultrathin crystalline silicon (c-Si) solar cells offer flexibility but struggle with light absorption and efficiency.
• Current limitations hinder the widespread adoption of these advanced solar technologies.

Purpose of the Study:

• To introduce a novel surface texturing method for enhancing light absorption in ultrathin c-Si solar cells.
• To improve the efficiency of flexible and invisible solar cell applications.

Main Methods:

• Developed correlated disordered hyperuniform patterns for surface texturing.
• Experimentally demonstrated light absorption in free-standing 1 μm c-Si layers using hyperuniform nanostructuring.
• Measured solar light absorption across the 400-1050 nm spectral range.

Main Results:

• Achieved 66.5% solar light absorption in 1 μm c-Si layers, significantly exceeding previous records for similar thicknesses.
• Demonstrated an absorption equivalent photocurrent of 26.3 mA/cm², a substantial improvement.
• Estimated potential cell efficiencies exceeding 15% with current technology and over 21% with added reflectors.

Conclusions:

• Hyperuniform nanostructuring effectively couples incident light into silicon slab optical modes, overcoming absorption limitations.
• This technique paves the way for highly efficient, thin, flexible, and potentially invisible solar cells.
• Future integration with back-reflectors and anti-reflection coatings promises even higher photovoltaic performance.