Scientists have developed a silicon solar cell with a geometry of holes with diameters of about 500-600 nanometers, according to a recent post on Physorg.com. The new design achieves an increased power efficiency of 9.5 percent, compared to the 5 percent efficiency of silicon cells that use optically active nanostructures such as nanowires and nanotubes.
The study, led by Kui-Qing Peng of Beijing Normal University and Shuit-Tong Lee of the City University of Hong Kong, was published in the Journal of the American Chemical Society.
The researchers say that the nanohole arrays have better absorption than nanowires. Also, the nanohole solar cell has shown to have superior mechanical robustness compared with the fragile structures of solar cells. In the past, this fragility problem has caused serious setbacks for manufacturing.
“The nanohole geometry solar cells possesses a robust structure compared with fragile free-standing nanowire geometry, a better ability for capturing sunlight than nanowire arrays, and radial p-n junctions allowing for enhanced carrier collection,” Lee summarized to PhysOrg.com.
Nanohole geometry has the potential for energy-efficient and cost-efficient photovoltaic solar energy conversion. The scientists plan to further improve the performance by improving the coupling of light into the device, employing surface passivation to minimize surface recombination and incorporating better electrical contacts.
“High optical absorption plus better carrier collection efficiency in nanohole geometry solar cells can be fabricated with less silicon materials and lower quality silicon,” Lee says. “These benefits would lead to efficient and less expensive solar cells, offering potentially competitive performance with traditional silicon-wafer cells, as well as cost-competitiveness with fossil fuels in the future.”