Arrangement of flexible foil substrates for CuInSe2-based solar cells

Metallic foils of aluminium, titanium, stainless steel and Ni-alloys (Kovar™) have been arranged as flexible substrates for thin film solar cells. For this purpose, they have been coated with SiO2 by a sol–gel process. Following this, Mo has been deposited by DC-sputtering onto the SiO2. The morphology, structure and optical properties of these samples have been analysed as grown and after annealing in a selenium atmosphere at temperatures ranging from 400 to 600°C. No selenium is incorporated in the samples but oxygen appears at all annealing temperatures as crystalline MoO2, decreasing the total optical reflectance. Only on Ti and Kovar™ foils does the molybdenum remain crack-free after annealing.