The third technique, being developed by Prashant Kamat of the University of Notre Dame, Indiana, and his colleagues, uses that fashionable scientific tool, the carbon nanotube.
Using this technique doubled the efficiency of Dr Kamat's cell from 5% to 10% at ultraviolet wavelengths and he reckons it would create similar increases in efficiency in both plastic and dye-based cells.
Dr Kamat and his team covered the surface of an experimental cell made of cadmium sulphide, zinc oxide and titanium dioxide with nanotubes, so that the tubes stuck up from the surface like hairs.