Towards very low-cost mass production of thin-film silicon photovoltaic (PV) solar modules on glass

Production volume of PV modules increases at > 35% per year, but one is yet far from making a global impact on energy supply. One of the obstacles is given by the present high production costs of PV modules. A possibility to reduce costs are thin-film PV modules on glass. The specific option of thin-film silicon is considered. The combination of amorphous and microcrystalline silicon thin films within a tandem solar cell corresponds to a theoretical optimum. In practice, stabilized efficiencies of 10% to 12% have so far been obtained in the laboratory with such tandem solar cells. Silicon being a material with an indirect band gap, its absorption coefficient is relatively low, and therefore light management in the solar cell has to be further optimized. Thin-film silicon can be deposited by plasma-enhanced CVD, as used for AM-LCD displays. The use of modified fabrication equipment from the AM-LCD Display Industry is therefore a promising way to implement low-cost mass production.