Researchers develop ultra-thin solar cells that capture 65% of sunlight

The cells, 100 times thinner than paper, could reduce solar production costs and increase its efficiency.

Researchers have developed a 1 μm (micrometer) thick solar cell capable of converting 66.5% of sunlight into electricity.

A scientific paper published in the journal ACS Photonics details a silicon cell that generates 26.3 mA/cm² (milliamperes per square centimeter) under laboratory conditions. This is a 25% increase from the previous ultrathin solar record of 19.72 mA/cm² achieved in 2017.

The researchers estimate that the cells, approximately 100 times thinner than a sheet of paper international standard, could be further improved to 33.8 mA/cm². This would create a photovoltaic cell with 21% efficiency, roughly in line with larger panels.

The developed ultra-thin solar cells are based on previously developed ultra-thin crystal structures, but use “correlated disordered hyperuniform patterns“. These allow more than twice the absorption of sunlight than a uniform silicon wafer.

Academics from Britain’s University of Surrey and Imperial College London worked with researchers from the Center for Nanophotonics and the Center for Advanced Research in Nanolithography, both in the Netherlands, to develop the cell.

The team fabricated the test cells using ultra-thin silicon crystals, “etching” them with patterns using electron beam lithography and etching fluids. The final product had a slightly varying thickness of approximately 1.18 μm in areas of 1.3 × 1.3 mm² or 4.8 × 4.8 mm².

The developers say they will now investigate the business partnership and potential manufacturing techniques.

One of the challenges of working with silicon is that nearly a third of light bounces directly off it without being absorbed or used for energy. A textured layer on top of the silicon helps solve this problem, and our messy yet hyper-uniform honeycomb design is particularly successful.

Dr Marian Florescu, Institute of Advanced Technology, University of Surrey

There is enormous potential for the use of ultra-thin photovoltaic solar energy. For example, given their lightness, they will be particularly useful in space and could make new projects viable. As they use much less silicon, it is expected that there will also be cost savings here on Earth, and there could be potential to bring more benefits from the Internet of Things and to create locally powered zero-energy buildings.

More information: (English text).

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