A new design increases the amount of sunlight that a solar absorber can convert into heat. The novel solar absorber could be used to make solar technology more efficient and affordable. The discovery is the result of a partnership between the Masdar Institute of Science and Technology in the United Arab Emirates and the Massachusetts Institute of Technology (MIT). The two institutes are collaborating on a larger project to design a solar-powered, combined electrical power plant and cooling system. Meanwhile, their solar absorber is a breakthrough for plasmonics, which is the study of the interaction between electromagnetic field and free electrons in a metal.
Our research team has developed a simple and cost-effective fabrication technique to create solar absorbers that can harness a greater share of the solar spectrum, thus increasing their efficiencies, while also maintaining low emission levels.
The new technique involves making a pattern of tiny holes in a solar absorber which is made from a semiconductor film and a reflective metallic layer. The holes maximize the range of solar energy that can be absorbed, enabling the absorber to capture nearly 90 percent of the wavelengths of light that reach the Earth’s surface. The pattern strikes the perfect balance—maximizing solar absorption while reducing thermal radiation of heat from the absorber.
“This idea can be applied to most conventional solar absorbers,” says Masdar Institute postdoctoral researcher Dr. Jin You Lu. “With this unique patterning, the absorbers can be boosted to harvest more solar energy from the ultraviolet and visible regions of the electromagnetic spectrum.” The study is published in the journal Advanced Optical Materials.