A recent discovery in the exotic optical effects on the nanoscale allows thinner and lighter solar cells to absorb a broader spectrum of light.Harry Atwater, a professor of Applied Physics and Materials at Caltech, and Koray Aydin, assistant professor of Electrical Engineering and Computer Science at Northwestern University, have discovered that by creating nanoscale wedge shapes with a wide base and a pointy tip, a material could capture a broader spectrum of light.Atwater and Aydin worked together to develop a super-absorbant solar cell using a property called optical resonance. The solar material uses nanoscale wedges that are of all different lengths, with pointed tops and wide bases. Blue light (440–500 nm) is absorbed at the tip and red light (625–740 nm) is absorbed at the base.The wavelengths for waves on the electromagnetic spectrum range from picometers (10^-12) to the 100s of megameters (10^6), so there’s a lot of ground to cover. The typical solar cell can only make use of waves within a narrow band of the already-narrow visible spectrum which covers only about 390- to 750-nanometer wavelengths.The material is made from a silver base with a layer of silicon dioxide above it, and finally a layer of silver with the carved out wedges. The film can also absorb light over the entire visible spectrum with an average measured absorption of 71% and a simulated absorption of 85%.Learn more from PC World.
Thinner Solar Cells Absorb Broader Spectrum of Light
