Solar panels are essential for creating a renewable energy ecosystem. Your existing versions can already produce clean energy from the most plentiful source available. But to improve their efficiency while lowering their cost to replace coal and gas based energy sources, technological advances are still needed. A team from New York University believes they have found a solution.
These researchers, led by Eray Aydil of the Department of Chemical and Biomolecular Engineering, addressed one of the facets of this solar cell inefficiency: the nature of light itself.
The problem with silica-based solar cells is that they are not the best choice based on the solar spectrum. With existing cells, only certain wavelengths can be used effectively. For example, ultraviolet and blue light do not convert to energy as well as infrared light. That means a good deal of the energy that could potentially be captured is wasted.
Essentially, the researchers’ solution is to “change the sun,” says Aydil. Scientists have developed a film that can be used in solar cells to modify the light spectrum, converting ultraviolet and blue light into light that borders infrared.
Changing the light spectrum has other advantages for solar cells. UV rays can lead to accelerated cell degradation, requiring more frequent replacement, thereby increasing electricity costs. UV rays can also lead to overheating due to the excess energy they contain, which in turn reduces the efficiency of solar cells and contributes to their accelerated degradation. By transferring these rays to infrared, the new film can solve several problems at once.
Trying to increase the efficiency of solar cells by changing the light spectrum has been the goal of many researchers for some time. The problem is that it can’t really be achieved in a series of small steps. Transposing 10% of the light doesn’t do much. And previous advances in this area have not exceeded a rate of 30%.
But in a recently published study in materials horizons, Mr. Aydil and his team claim to be able to achieve a conversion rate of more than 82%. Other works to be published even mention a conversion rate of more than 95%. It is also possible to go beyond 100%. At this stage it would be possible to get two infrared photons for one ultraviolet photon.
However, the team needs to start incorporating their foil into an existing solar cell to determine its effectiveness in real-world conditions.
Said film could have another trick up its sleeve: it is the only material of this type that does not require lead. Finally, lead is a dangerous chemical, and extracting it from the ground can cause environmental disasters. And if that same lead eventually finds its way into the environment, cleanup can be a headache. Indeed, taking the lead out of the equation makes the production and installation of new films much more attractive for manufacturers.