Why Have Investors Flocked to CIGS Solar?
Efficiency Promises versus Broken Promises The promise of CIGS cells is that high-efficiency cells can be achieved using less than 1/100th the semiconducting materials required for silicon-based PV cells. At the same time, CIGS cells present a challenge because four-layers of semiconducting material (copper, indium, gallium and di-selenide, or in some cases sulfur) must be deposited correctly to create an efficient cell. (Image on right is a Global Solar CIGS cell) Correction: An astute reader points out that I got this a bit wrong. “The CIGS in the solar cells is not a four-layer stack (and more particularly, di-selenide is not a material per se) Rather, it is a chemical compound, a crystal where one copper atom, one indium or gallium atom and two selenium atoms (hence di-selenide) make up each basic unit. You can talk about the challenge of getting four-layer structures right, but then it’s the structure back contact–absorber–buffer–window.” I stand corrected. On with the story… Ever
