Solar cells are the key components of creating a sustainable future. As the world tries to reduce costs and make solar energy more viable, researchers have come up with a way to make the sun do their bidding. Yes, you read that right.
Shifting the Sun
A team of researchers led by Eray Aydil in the Chemical and Biomolecular Engineering Department is tackling one facet of solar cells’ inefficiency – sunshine itself.
Photovoltaic arrays and cells help produce clean energy from the sun. But the problem with silicon photovoltaic cells is that they are not a perfect match for the solar energy sources. The ultraviolet rays, along with blue light, are not utilized by energy sources as they cannot be converted to energy. The researchers have been able to address this problem of wastage.
The team was able to develop a film that can be used in solar cells to shift the light spectrum – turning blue light and ultraviolet light into near infrared light – that can be utilized as a fuel source for solar cells. Altering the light spectrum comes with a mixed bag of uses for the cells.
If ultraviolet (UV) rays are directly used by the cells, it may cause them to deteriorate faster, which will result in additional charges as they will have to be replaced much earlier than expected. UV rays can also be dangerous as they can cause overheating of the panels, lowering its efficiency and increasing costs. By managing to convert these rays to the near-infrared spectrum, the researchers have been able to eliminate multiple bottlenecks in one smooth stroke.
Many researchers have time and again tried to alter the sunshine spectrum for better efficiency. Earlier attempts fell short by 30% as shifting the light by just 10% does not accomplish much. However, Aydil’s team was able to push it to over 82%, while an upcoming paper is expected to reveal that they have touched up to 95%. They are currently exploring the possibility of pushing it to 100%, wherein it will be possible to get two infrared photons out of every UV photon. The researchers are working to make it possible and to see how this will impact the efficiency of the material.
One attractive feature of this film is its elimination of lead. Lead is widely used in electrical components, but is extremely dangerous to humans. Exposure to high levels can cause everything from weakness to brain damage. Not to mention the high clean up costs. As lead is no longer part of this film, it makes the product much more attractive to buyers and producers.
Meanwhile, the team is focused on pushing it to 100% so that renewable energy can be cost effective and efficient, as the world grapples with changes brought on by climate change.
Renewable energy
Renewable energy sources, such as biomass, geothermal resources, sunlight, water, and wind, can be converted to clean energy for daily use. Although they are limited, they are naturally replenishing and available at minimal cost.
Solar energy accounted for 3.1% of electricity generation in the world, and is the third largest renewable energy behind hydropower and wind energy. Countries across the world invested heavily in solar energy as the world tries to meet its sustainable goals by 2030. However, much more effort is needed if we are to meet net zero goals by 2030. Solar PV capacity in the US and Europe witnessed double-digit growth in 2020. Germany topped the list with the highest growth.
In the last year, Asian countries have taken to building floating solar farms, which capture energy in a cost-effective manner. India and China have specially stepped out efforts to meet their energy needs using floating photovaltics. A 320 megawatt (MW) project in Dezhou, China, is the biggest floating farm to come online to date.
