One of these materials, molybdenum disulfide, is being extensively studied for its light detection properties, but Indian copper selenide (CIS) also shows an extraordinary promise. Sidong Lei, a graduate student in Rice's laboratory of materials scientist Pulickel Ajayan, synthesized CIS, a single-layered array of copper, indium and selenium atoms. Lei also built a prototype - a three-pixel loading device (CCD) - to test the ability of material to capture an image.
"Traditional CCDs are thick and rigid, and it would not make sense to combine them with 2D elements," says Lei. "CIS-based CCDs would be ultra slim, transparent and flexible, and are the missing piece for things like 2D imaging devices." CIS pixels are highly sensitive to light because entrapped electrons (formed by incident light) dissipate so slowly.
According to rice materials scientist Robert Vajtai, there are many two-dimensional materials that can detect light, but none is as efficient as this material, which he claims is ten times more efficient than the best discovered so far.