Unlike crystalline silicon which is an indirect band-gap semiconductor, CIGS is a direct band-gap semiconductor, which can generate more power per unit of material. One micron thick CIGS can produce as much photoelectric effect as 200-300 microns thick silicon crystalline. Therefore, CIGS is less expensive than traditional solar cell. Because only small amount of CIGS is needed on a film, the film can be made very thin making it flexible. Not only that, another advantage of CIGS film over crystalline silicon is that CIGS is more efficient in low angle and light intensity, which makes CIGS solar cell more feasible in real-world applications where sky will not be always clear and sun will not be shinning straight down into the solar cell. In overall, Miasolé’s solar cells are thin, light-weight, flexible, practical, and low cost (compare to traditional solar cell).

(via Miasolé and Wikipedia; image credit: Miasole (SolarPlaza))