Breakthrough for carbon nanotube solar cells

Lighter, more flexible, and cheaper than conventional solar-cell materials, carbon nanotubes (CNTs) have long shown promise for photovoltaics. But research stalled when CNTs proved to be inefficient, converting far less sunlight into power than other methods.

Now a research team led by Mark Hersam, professor of materials science and engineering and the Bette and Neison Harris Chair of Teaching Excellence at Northwestern University's McCormick School of Engineering, has created a new type of CNT solar cell that is twice as efficient as its predecessors. It is also the first CNT solar cell to have its performance certified by the National Renewable Energy Laboratory.

"The field had been hovering around 1 percent efficiency for about a decade; it had really plateaued," Hersam said. "But we've been able to increase it to over 3 percent. It's a significant jump."

The research is described in the article "Polychiral Semiconducting Carbon Nanotube-Fullerene Solar Cells" in the August 7 issue of Nano Letters.