Why CIGS?
"CIGS" is a descriptive abbreviation for Copper Indium Gallium Diselenide, a Thin Film Photovoltaic (TFPV) solar cell.
CIGS has several characteristics that make it a valuable PV material.
- Tolerant Chemistry
Good performance achieved with a wide range of Cu/(In+Ga) and Ga/(In +Ga) composition ratios
- Thin-Film Nature CIGS absorber is ~2.5 um compared to ~170 to 250 um for Si
- Non-Toxic CIGS Does Not have Reportable Quantities of Hazardous Substances Ref: Vasilis Fthenakis, Brookhaven National Lab
- CIGS is less susceptible to commodity pricing of raw materials or to material shortages
- CIGS's absorption coefficient is among the highest for semiconductor materials used to make solar cells. Ninety-nine percent of the light incident on a CIGS based solar cell is absorbed in the first micrometer of the device. This provides the opportunity to produce thinner films and the reduction of material costs.
- Because CIGS films retain their performance properties better and do not degrade as rapidly as other thin-films such as CdTe and a-Si used for TFPV, CIGS solar modules will reliably produce power in a range close to their original performance potential well into the future.
- CIGS is also amenable to automated production techniques. Thin Films, like CIGS, benefit from low production costs that combine automated production processes with low material costs. CIGS offers a viable opportunity to utilize automated manufacturing techniques witout sacrificing TFPV conversion potential.
- Thin-film solar cells made from CIGS absorbers show great promise in achieving the highest theoretical thin-film conversion efficiencies (approaching 29% and more). As CIGS currently holds the world record for Thin Film conversion efficiency at 19.9%, this may make CIGS one of the only truly viable thin-film candidates to compete with silicon.