A tablet-size device based on a new ceramic material could help achieve low-cost and more efficient solar panels, according to a new study. The solar panel design uses the bulk photovoltaic material to harness energy from visible and infrared light, potentially offering cheaper and more sustainable power based on less manufacturing time.
The research by a team from the University of Pennsylvania and Drexel University, which was published in Nature [Grinberg, et al., Nature (2013), doi:10.1038/nature12622], showed how a material using perovskite crystals based on a combination of potassium niobate and barium nickel niobate could improve on the standard ferroelectric material, being able to absorb six times more energy and transfer a photocurrent 50 times denser.
The new class of ceramic materials has a number of benefits, such as thinner solar panels than standard silicon-based devices, and cheaper materials than in current high-end thin-film solar panels. Being ferroelectric, it can switch polarity, improving its energy efficiency. As researcher Jonathan Spanier points out, “This family of materials is all the more remarkable because it is comprised of inexpensive, non-toxic and earth-abundant elements, unlike compound semiconductor materials currently used in efficient thin-film solar cell technology”.
Solar panels have less than desired efficiency because the sun's particles scatter in every direction upon entering a solar cell. Forcing them to flow in a single direction requires layers of different channeling materials; despite this, some particles moving between the layers are still lost, reducing the cell's energy efficiency. The scientists used X-ray crystallography and high-resolution powder diffraction data to resolve if the material had the necessary crystal structure and symmetry, demonstrating that it is able to move energy in one direction without crossing layers – a bulk photovoltaic effect – lowering potential energy loss.
Altering the percentages of component elements in the new material also means they can reduce the material's bandgap. Spanier said “The parent material's bandgap is in the UV range, but adding just 10 percent of the barium nickel niobate moves the bandgap into the visible range and close to the desired value for efficient solar-energy conversion.” The team hopes that further tuning of the material's composition will help its efficiency, although there is still much to be done to scale up the design to a working solar panel.
Copyright © 2014 Published by Elsevier Ltd.