Iron sulfide, a new substance ... A few of these elements can be found pure in a natural state. For example, graphite and diamond can be found in rocks in the Earth’s crust, and they are ...

Pure sulfide chalcopyrite, Cu(In,Ga)S 2, is a promising semiconductor material with a bandgap between 1.5 and 2.4 eV, which has already been used to build single-junction and tandem solar cells.