Renewable energy, such as solar power and wind power, is the future. Anyone who says otherwise is a nincompoop. Despite the “oil boom” in North Dakota and elsewhere, fossil fuel supplies are dwindling, as finite resources tend to do. Despite all of renewable energy’s obvious advantages—no pollution, literally an infinite supply, etc.—the technology still has trouble competing with fossil fuels on a large scale. This is, in part, because of the expense of renewable energy systems, particularly solar cells.
Nanoholes To the Rescue
A new technological breakthrough may go a long way to leveling the playing field, however. Xincai Wang from the A*STAR Singapore Institute of Manufacturing Technology, assisted by colleagues from Nanyang Technological University, has discovered a new way to increase the cost-effectiveness of photovoltaic devices.
Wang and The Gang discovered a new way to add nanoholes to the cells’ silicon wafers, which greatly enhances the light-harvesting capabilities of those cells. Nanoholes—which, as the name suggests, are just tiny surface cavities—are exceptionally effective light catchers; photons tend to ricochet around the holes multiple times before they’re fully absorbed, boosting efficiency.
New! Faster, Easier Nanoholing
The previously accepted nanoholing method, lithography, was effective, but slow, and often led to defects in the solar cell. Wang and The Gang’s new method utilizes silver nanoparticles for fast, “maskless” processing. Prior to the wafer dicing and grinding processes, a layer of silver only a nanometer thick is deposited on the wafer. Then, using rapid-burst ultraviolet lasers, this silver layer is toughened. By really, really knowing what the heck they’re doing, the scientists were able to create consistently sized and distributed silver nanospheres on the surface of the wafers.
A solution of hydrogen peroxide and hydrofluoric acid eats away the silicon atoms under the silver nanospheres. A second acid solution is used to remove the silver particles, et voila! Nanoholes aplenty.
“[This] process for making hybrid silicon nanohole devices can successfully reduce the fabrication costs which impede the solar cell industry,” Wang said. “This approach can be easily transferred to silicon thin films to develop thin-film silicon-polymer hybrid solar cells with even higher efficiency.”
Hear that, Big Oil? That’s the sound of your days being numbered. Solar FTW!
- Phys.org: “Simple, inexpensive fabrication procedure boosts light-capturing capabilities of tiny holes carved into silicon wafers”
Photo credit: Foter / Creative Commons Attribution 3.0 Unported (CC BY 3.0)