CIGS cells use extremely thin layers of semiconductor material applied to a low-cost backing such as glass, flexible metallic foils, high-temperature polymers or stainless steel sheets. Thin-film cells require less energy to make and can be fabricated by a variety of processes. Because of this, they provide a promising path for providing more affordable solar cells for residential and other uses. The CIGS cells are of interest for space applications and the portable electronics market because of their light weight. They are also suitable in special architectural uses, such as photovoltaic roof shingles, windows, siding and others.
For a long time, thin-film scientists have been working to get costs lower and lower, with less concern for the efficiency of the cells. However, shortages in indium, one of the elements used in making the cells, has renewed interest in increasing efficiency. And, of course, any efficiency increase helps to make the panels more economical over the lifetime of the cell.