Increasing the efficiency of a hybrid solar cell simply by placing it near a source of ambient noise or vibration would be a boon for photovoltaics in urban areas, in the military, or on machinery or transportation. Hybrid organic/inorganic solar cells are already a tempting option over silicon because of their lower cost, but they suffer from their own drawbacks of efficiency. However, new research demonstrates that the piezoelectric qualities of the cells’ inorganic layer can be used to boost the overall efficiency of hybrid systems, which is promising for wherever sound and sun are together.
Piezoelectric materials generate electricity when exposed to vibrations, sound, and even touch. While it’s known that the zinc oxide (ZnO) nanotubes studied in this research have piezoelectric properties, few studies have addressed it. Additionally, focus has been on the electricity generated by the piezoelectric effect itself, a negligible percentage of the overall output, rather than how this layer interacts in its hybrid sandwich.
Read more here http://www.gizmag.com/vibration-sound-efficient-hybrid-solar-cell-arrays/29679/