Silicon solar cells have come a long way from those that Bell Labs first debuted in the 1950s. Advances in light capture and conversion efficiency have improved significantly. And yet they still have limitations.
For one, it takes a lot of energy to melt silicon dioxide in order to remove the oxygen attached to its molecular make up, which drives up cost and greenhouse gas emissions. Furthermore, the power conversion efficiency of silicon panels has remained at about 25% for 15 years and their rigidity and weight limit where they can be installed. Enter perovskites.
The term “perovskites” refers to a range of materials made primarily of carbon and hydrogen molecules bonded in a three-dimensional crystal latticework with metals such as lead and halogen such as chlorine. Thousands of different chemical compositions are possible within this class of material.
Today, perovskites can be made relatively cheaply and with fewer emissions than solar panel production. According to Scientific American, “Manufacturers can mix up batches of liquid solutions and then deposit the perovskites as thin films on surfaces of virtually any shape, no furnace needed. The film itself weighs very little.”
And researchers have recently discovered a way to boost the efficiency of perovskite solar cells by capitalizing on the material’s nanoscale peaks and valleys as the journal, Nature Energy, reported on July 4.
A team of scientists from the Department of Energy’s Lawrence Berkeley National Laboratory mapped properties that relate to the photovoltaic efficiency of perovskites. The maps revealed a bumpy surface composed of grains about 200 nanometers in length with multi-angled facets. In addition, the maps showed a huge difference in energy conversion efficiency between the different facets. Some were poorly performing, while others reached a high rate of energy conversion efficiency.
“If the material can be synthesized so that only very efficient facets develop, then we could see a big jump in the efficiency of perovskite solar cells, possibly approaching 31 percent,” Sibel Leblebici, a postdoctoral researcher at the Molecular Foundry, said in a statement.
These findings suggest that producing perovskites with high-performing facets would allow far more efficient solar cells. The energy-producing potential has the scientific community on the edge of its seat. Could optimizing these tiny facets be the future of solar?