Photocathodes layered with Graphene Produces Electricity


Scientists developed a method halide perovskites, to insulate photocathodes with thin graphene layers for converting photons into electricity.

Devices such as solar cells generate electricity from light in a closed circuit. However, some materials such as photocathodes are able to generate large amount of electricity of free electrons that could be used for physical experiments.

Photocathodes decomposes on exposure to air, therefore scientists at the .S. Department of Energy’s (DOE) Argonne, Brookhaven, and Los Alamos national laboratories introduced a new method to enclose photocathode with a thin layer of graphene, to protect it and extend its life. Photocathodes work on the principle of photoelectric effect. During photoelectric effect, the electrons are ejected from metal’s surface with a beam of light coming at a certain frequency. In photocathodes, the photon of light gets converted into electrons through the process of photoelectric effect. These electrons generated could be used in accelerator systems or in in photodetector systems for high-energy physics experiments that operate in low-light environments in which every photon counts.

Photocathodes have high efficiency in quantum electrons and the graphene layers protect photons for a larger period. The potential in generating electrons is directly proportional to the quantum efficiency of the material.

The team of researchers observed potassium cesium antimonide, with the highest quantum efficiency of any known photocathode in the visible range of the spectrum. However, potassium cesium antimonide photocathodes on exposure to air broke down, therefore scientist thought of another method to capture electricity using photocathodes.

The researchers took graphene to coat photocathode as the properties of the metal was exactly they were looking for. Graphene is a two dimensional material made of carbon atoms that can form thin layers and could conduct electricity. The graphene-wrapping technique called as halide perovskites could be used for any photocathodes that is accompanied with air exposure.


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