Scientists at Stanford University have succeeded in building light-absorbers that are thousands of times thinner than a sheet of paper. The nanosize structures are capable of absorbing close to 100 % of visible light emanating from specific wavelengths.
Researchers believe the material could be used to make cheaper, more efficient solar cells.
An ideal solar cell would be able to absorb the entire visible light spectrum, from violet light waves 400 nanometers long to red waves 700 nanometers in length, not to mention invisible ultraviolet and infrared light.
The researchers’ results were illuminating. The coated wafers absorbed 99% of the reddish-orange light, and they achieved 93% absorption in the gold nanodots themselves. Each dot’s volume is equivalent to a layer of gold 1.6 nanometers thick. This makes it the thinnest absorber of visible light on record, and is 1,000 times thinner than commercially available thin film solar cell absorbers.
The primary goal is to develop improved solar cells and solar fuel devices by confining the absorption of sunlight to the smallest amount of material possible. This will provide a benefit by minimizing the material necessary to build the device, and should allow for higher efficiencies. The charge carriers will be produced very close to where they are desired and will be collected to produce an electrical current or to drive a chemical reaction.