This illustration shows a prototype device comprising bare nanospring photodetectors placed on a glass substrate, with metal contacts to collect charges (credit: Tural Khudiyev and Mehmet Bayindir/Applied Optics)
Researchers from Bilkent University, Ankara, Turkey, have shown that twisting straight nanowires into springs can increase the amount of light the wires absorb by up to 23 percent. Absorbing more light is important because one application of nanowires is turning light into electricity, for example, to power tiny sensors instead of requiring batteries.
If nanowires are made from a semiconductor like silicon, light striking the wire will dislodge electrons from the crystal lattice, leaving positively charged “holes” behind. Both the electrons and the holes move through the material to generate electricity. The more light the wire absorbs; the more electricity it generates. (A device that converts light into electricity can function as either a solar cell or a photosensor.)