The word ‘cadmium’ (Cd) has a negative connotation to anyone who deals with solder alloys or health and safety regulations. If you are using toxic cadmium sulfide as a buffer layer for CIGS PV cells, I urge you to explore indium sulfide (In2S3) as a replacement. Alternative energy should focus on being environmentally conscious, starting with the bill of materials for the solar cell.
By the way, that's indium sulfide in the picture. Pretty cool, huh?