Researchers from the Universities of Bristol and Exeter in the UK are developing inexpensive, high efficiency solar cells made of gold and diamond-like (amorphous) carbon. They created a cell that can potentially reach much higher temperatures than traditional surfaces because it can minimize the emission of thermal radiation. It is part of a larger project aimed at developing diamond-based solar devices that use sunlight to get surfaces hot enough to emit electrons directly into a vacuum. Martin Cryan, Professor of Applied Electromagnetics and Photonics in the Department of Electrical and Electronic Engineering, at Bristol said:
Integrating diamond within metasurfaces is very challenging, and this paper is a first step in that direction using amorphous carbon. The next stage is to carry out high temperature testing on the structures and to attempt to reach the ~700 degrees celsius required to obtain efficient thermionic emission.
The system they have developed so far uses a layer of diamond-like carbon between thin gold films. The upper film is patterned with a 2D period array using focused ion beam etching. This metasurface strongly absorbs light across the solar spectrum but minimizes emission of thermal radiation from the structure. It is described in detail in a paper called “A selective metasurface absorber with an amorphous carbon interlayer for solar thermal applications” that published in Nano Energy on May 26, 2016.