A new study from researchers at the University of York has found that designing solar cells with checkerboard lines could increase their ability to absorb light by 125% and could lead to a wider use of renewable energy.
Researchers from the University of York in England, in collaboration with NOVA University of Lisbon in Portugal, have recently published a study investigating how different solar cell surface designs affected the absorption of sunlight in solar panels.
The study, Light trapping in solar cells: simple design rules to maximize absorption, published in the open access journal Optica, sought to investigate a simpler approach to increasing a solar cell’s light trapping ability – which is to say, increasing its solar absorption abilities.
Currently, according to the researchers, many of the enhanced light-trapping structures designed over recent years, while effective in increasing a solar cell’s performance, are nevertheless more complicated designs and, as such, are less likely to be integrated into industrial application.
The researchers note that “their industrial application rather depends on simplicity concerning the integration to the solar cell concept and the process technology.”
In an attempt to simplify solar cell design while increasing solar absorption, the researchers demonstrated how “simple grating lines” in a checkerboard arrangement on the solar cell “can perform as well as advanced light-trapping designs.”
Diffraction grating lines on solar cells, according to a 2008 article, “were introduced into thin-film solar cells as a means for a better control of light-scattering inside the cells.” The introduction of linear grating lines serves “to supress the total reflection in the wavelength region of interest and to scatter light into (pre) selected angles.”
In other words, these simple grating lines printed onto the surface of a solar cell serve to diffract incoming light into several separate beams, travelling in separate directions, to increase the performance of the solar cell.
However, according to the University of York and NOVA University of Lisbon researchers, “simple grating lines have only shown marginal absorption improvements in solar cell materials,” and led to a belief that simple grating liens could not become the pillar of advanced solar innovation.
Conversely, “the belief that they cannot be the pillar of advanced photonic concepts triggered a new research field to analyze more and more complicated and evermore efficient light-trapping schemes at the expense of their complexity.”
That’s where the new research comes in, investigating different grating designs, such as rose, zigzag, and checkerboard. The researchers found that the checkerboard grating design performed the best, so much so in fact that they show it could enhance light absorption by 125%.
The checkerboard design particularly improves diffraction, which in turn enhances the probability of light being absorbed, which is then used to create electricity.
“We found a simple trick for boosting the absorption of slim solar cells,” said Dr Christian Schuster from the Department of Physics at the University of York.
“Our investigations show that our idea actually rivals the absorption enhancement of more sophisticated designs — while also absorbing more light deep in the plane and less light near the surface structure itself.
“Our design rule meets all relevant aspects of light-trapping for solar cells, clearing the way for simple, practical, and yet outstanding diffractive structures, with a potential impact beyond photonic applications.
“This design offers potential to further integrate solar cells into thinner, flexible materials and therefore create more opportunity to use solar power in more products.”
A potential major outcome from this study is not only the increased light absorption for solar cells, but the simplification of the design, which could lead to the production of thinner, lighter, and more flexible solar panels.
This, in turn, could lead to solar panels being used on more homes and in a wider array of products and applications. The researchers also believe these new grating designs will reduce the need for thicker, more complex solar panels, making them cheaper and more environmentally friendly.
“In principle, we would deploy ten times more solar power with the same amount of absorber material: ten times thinner solar cells could enable a rapid expansion of photovoltaics, increase solar electricity production, and greatly reduce our carbon footprint,” Dr Schuster added.
“In fact, as refining the silicon raw material is such an energy-intensive process, ten times thinner silicon cells would not only reduce the need for refineries but also cost less, hence empowering our transition to a greener economy.”