The thin silicon membrane uses a disordered honeycomb layer to maximize the absorption of sunlight. Image: University of Surrey.
The thin silicon membrane uses a disordered honeycomb layer to maximize the absorption of sunlight. Image: University of Surrey.

A team co-led by researchers at the University of Surrey in the UK has successfully increased the levels of energy absorbed by wafer-thin photovoltaic panels by 25%. Their solar panels, just 1μm thick, can convert light into electricity more efficiently than other panels with the same thickness, and could pave the way to making it easier to generate more clean, green energy.

In a paper in ACS Photonics, the researchers report how they used characteristics of sunlight to design a disordered honeycomb layer that lies on top of a wafer of silicon. Their approach is echoed in nature in the design of butterfly wings and bird eyes. This innovative honeycomb design enables light absorption from any angle and traps light inside the solar cell, allowing more energy to be generated.

“One of the challenges of working with silicon is that nearly a third of light bounces straight off it without being absorbed and the energy harnessed,” said Marian Florescu from the University of Surrey’s Advanced Technology Institute (ATI). “A textured layer across the silicon helps tackle this, and our disordered yet hyperuniform honeycomb design is particularly successful.”

The team of researchers from the University of Surrey and Imperial College London in the UK worked with experimental collaborators at AMOLF in Amsterdam, the Netherlands, to design, model and create the new ultra-thin photovoltaic.

In the laboratory, the researchers achieved absorption rates of 26.3mA/cm2, a 25% increase on the previous record of 19.72mA/cm2 achieved in 2017. They secured an energy conversion efficiency of 21% but anticipate that further improvements will push this figure higher, resulting in efficiencies that are significantly better than many commercially available photovoltaics.

“There’s enormous potential for using ultra-thin photovoltaics,” said Florescu. “For example, given how light they are, they will be particularly useful in space and could make new extra-terrestrial projects viable. Since they use so much less silicon, we are hoping there will be cost savings here on Earth as well, plus there could be potential to bring more benefits from the Internet of Things and to create zero-energy buildings powered locally.”

As well as benefiting solar power generation, the findings could also benefit other industries where light management and surface engineering are crucial, such as photo-electrochemistry, solid-state light emission and photodetectors. Next steps for the team will include investigating commercial partners and developing manufacturing techniques.

This story is adapted from material from the University of Surrey, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.