Spray-on Solar Panel Efficiency

Current commercial photovoltaic (PV) solar technologies rely on solar cells that are made of silicon that's been coated with a thin layer of silicon nitrate (the silicon nitrate works as an anti-reflective material to increase the cell's sunlight collecting efficiency). They're costly to manufacture for two reasons: They use hydrogen plasma to collect sunlight and they are made in a vacuum. Thin-film PV cells use cheaper materials but are more complex to make -- and despite the cheaper materials, the production complexity equals a more expensive end product.

Enter the spray-on solar material project. Researchers are experimenting with ways to change how solar cells are manufactured, as well as how to increase solar cell efficiency.

Phase one of their project is an effort to bring down both the complexity of the manufacturing process and the associated high cost. Their new method involves spraying solar panels as they roll down a conveyor belt during production, first with a hydrogen film and then an anti-reflective film.

Solar cells are made from semi-conducting nanoparticles called quantum dots. These quantum dots are mixed with a conducting polymer to make a plastic. Spray-on solar panels composed of this material can be manufactured to be lighter, stronger, cleaner and generally less expensive than most other solar cells in production today. They are the first solar cells able to collect not only visible light but infrared waves, too.

Phase two of the ANU project, in collaboration with the German solar company GP Solar, will study ways of increasing the efficiency of the cells. Researchers are exploring how the surface of a solar cell (specifically, it's roughness) affects its ability to collect solar energy. Right now, the efficiency rate of solar cells on the market is about 15 percent. By comparison, the first solar cells manufactured in the 1950s converted less than 4 percent of collected solar energy into usable power [source: National Renewable Energy Laboratory]. Scientists predict they may be able to increase that rate by five times the current numbers [source: Locgren].