Solar superabsorber to improve photovoltiac efficiency

It is claimed the superabsorbing design could decrease the thickness of the semiconductor materials used in thin film solar cells by more than one order of magnitude without compromising the capability of solar light absorption.

‘State-of-the-art thin film solar cells require an amorphous silicon layer that is about 100nm thick to capture the majority of the available solar energy,’ said Dr. Linyou Cao, an assistant professor of materials science and engineering at NC State and senior author of a paper describing the work. ‘The structure we’re proposing can absorb 90 per cent of available solar energy using only a 10nm thick layer of amorphous silicon.

‘The same is true for other materials. For example, you need a cadmium telluride layer that is one micrometer thick to absorb solar energy, but our design can achieve the same results with a 50nm thick layer of cadmium telluride. Our design can also enable a 30nm thick layer of copper indium gallium selenide to fully absorb solar light. That’s a huge advance.’