Swiss researchers say they've developed thin, flexible solar cells with a record efficiency of 20.4 percent for converting sunlight into electricity.

Scientists at the Swiss Federal Laboratories for Materials Science and Technology say the cells on flexible polymer foils offer a significant improvement over the previous record of 18.7 percent.

Such lightweight and flexible high-performance solar modules will offer an attractive technology for applications such as solar farms, roofs and facades of buildings, automobiles and portable electronics, the Swiss lab said in a release.

They are also closing the efficiency gap with rigid, silicon wafer cells, the researchers said, and can be produced using a continuous roll manufacturing processes that should offer further cost reductions compared with standard silicon technologies.

The cells are based on CIGS semiconducting material (copper indium gallium (di)selenide.)

"The series of record efficiencies for flexible CIGS solar cells developed at [the lab] demonstrates that thin film solar cells can match the excellent performance of polycrystalline silicon cells," lab director Gian-Luca Bona said.

"Now it is time for the next step, the scale-up of the technology to cover large areas in a cost-efficient roll-to-roll manufacturing process with an industrial partner."