New: Molybdenum-tantalum against corrosion in CIGS.

Thanks to its good adhesion to glass and a high electrical conductivity, molybdenum is the back contact material in CIGS solar cells. However, exposed to corrosive atmospheres molybdenum can be prone to oxidation. Our answer: Molybdenum-tantalum.

We alloy pure molybdenum with small amounts of corrosion-resistant tantalum, and thereby combine the advanced properties of both metals. The superior corrosion resistance of molybdenum-tantalum (MoTa) has been proven in numerous tests. Below you can see the result of a corrosion experiment at elevated temperature (60 °C) and high humidity (90%): The carved thin films (layer thickness: 300 nm) of MoTa exhibit a much better corrosion resistance, compared with pure molybdenum.

Molybdenum:
Exposure 0 h
Molybdenum:
Exposure 50 h
Molybdenum:
Exposure 100 h
MoTa:
Exposure 0 h
MoTa:
Exposure 50 h
MoTa:
Exposure 100 h

 

But MoTa not only functions as a back contact material. On flexible substrates like stainless steel foil and polyimide the new alloy can function as a corrosion resistant contact and protective layer. It effectively protects the backside of the stainless steel web during the selenization step in the CIGS manufacturing process.