Tell it to the trees

Nanoscopic "trees" can harvest sunlight and use it to convert water into hydrogen fuel, according to research from the University of California, San Diego. Deli Wang and colleagues have created a branched nanoarray from silicon/zinc oxide nanowires to produce an enormous surface area for energy harvesting. Photons bounce between the branches of the 3D branched nanowire heterojunction photoelectrodes and so increase water photolysis and so release hydrogen more efficiently than planar materials. The next step is to find a more stable alternative to zinc oxide.