Transparent solar materials applied to windows can harvest as much energy from invisible light waves as bigger, bulkier rooftop solar units, scientists say.
Widespread use of such highly transparent solar applications, together with the rooftop units, could drastically reduce the use of fossil fuels.
“Highly transparent solar cells represent the wave of the future for new solar applications,” said Richard Lunt, from Michigan State University in the US.
“We analysed their potential and show that by harvesting only invisible light, these devices can provide a similar electricity-generation potential as rooftop solar while providing additional functionality to enhance the efficiency of buildings, automobiles and mobile electronics,” said Lunt.
Researchers pioneered the development of a transparent luminescent solar concentrator that when placed on a window creates solar energy without disrupting the view.
The thin, plastic-like material can be used on buildings, car windows, cell phones or other devices with a clear surface.
The solar-harvesting system uses organic molecules developed by Lunt and his team to absorb invisible wavelengths of sunlight.
The researchers can “tune” these materials to pick up just the ultraviolet and the near-infrared wavelengths that then convert this energy into electricity.
Moving global energy consumption away from fossil fuels will require such innovative and cost-effective renewable energy technologies.
Only about 1.5 per cent of electricity demand in the US and globally is produced by solar power.
However, in terms of overall electricity potential, there is an estimated five billion to seven billion square meters of glass surface in the US.
With that much glass to cover, transparent solar technologies have the potential of supplying some 40 per cent of energy demand in the US – about the same potential as rooftop solar units.
Lunt said highly transparent solar applications are recording efficiencies above five per cent, while traditional solar panels typically are about 15 per cent to 18 per cent efficient.
Although transparent solar technologies will never be more efficient at converting solar energy to electricity than their opaque counterparts, they can get close and offer the potential to be applied to a lot more additional surface area, he said.
Right now, transparent solar technologies are only at about a third of their realistic overall potential, Lunt added.
“Traditional solar applications have been actively researched for over five decades, yet we have only been working on these highly transparent solar cells for about five years,” he said.
“Ultimately, this technology offers a promising route to inexpensive, widespread solar adoption on small and large surfaces that were previously inaccessible,” he added.