Cadmium telluride and other thin-film solar power materials are emerging as competitors to the more common silicon wafer technology. Thin films allow for rapid production of more flexible, lightweight solar panels, expanding the options for design and application.

The conversion efficiency of thin films has plateaued at 22.1%, underscoring the need to effect greater control The vapor transport deposition system improves the efficiency and lowers costs of thin-film photovoltaics. Source: Evan Krape, University of Delawareof material properties in ways that improve solar cell performance. But researchers from the University of Delaware and the National Renewable Energy Laboratory have developed a vapor transport deposition system that attains voltages over 1 volt and efficiencies of 25% in cadmium telluride closer to reality.

The system adjusts properties of crystalline grains during film growth through the addition of small quantities of additional elements into the film’s crystals. This new approach to doping raises the conductivity and increases the voltage that can be produced by the cell. The result is more efficient electron flow and greater device output.

Three doping treatments applied to cadmium telluride used antimony, arsenic and phosphorus. Each imparted improved doping levels, with arsenic and antimony yielding the highest acceptor concentrations in excess of 1,016 cm³ without compromising carrier lifetime.

The research is published in Scientific Reports.