Amorphous silicon alloy solar cells and modules-opportunities and challenges

The low material cost and proven manufacturability of amorphous silicon (a-Si) alloy solar panels make them ideally suited for low-cost terrestrial application. a-Si alloy solar panels have been commercially available for more than a decade for applications ranging from small calculators to large-scale grid-connected power systems. Extensive R&D efforts have resulted in a significant improvement in stable cell and module efficiencies with the achievement of 11.8% cell efficiency and 10.2% module efficiency using a spectral-splitting triple-bandgap, triple-cell approach. Further gains in efficiency are expected through an improved understanding of plasma chemistry and growth kinetics. Large-scale commercialization programs are under way, with proposed expansion of annual production capacities exceeding 25 MW to take place within the next one year. This will make a-Si alloy the dominant photovoltaic technology. In this paper, the author discusses the progress in science, technology and commercialization of a-Si alloy photovoltaics with special emphasis on the opportunities and the challenges that exist