You may not be able to get mad at your neighbor for blasting loud music anymore. At least not if that music is aimed at making the solar cells on his roof work more efficiently. According to an article reported by science writer Ceri Perkins on physicsworld.com, researchers in the UK have discovered that blasting music at zinc-oxide solar cells makes them perform up to 50% better. The researchers said pop and rock music works better than classical music, but they suggested that any noise with a broad range of frequencies would produce similar effects. The discovery might be exploited by placing the devices on top of buses, air-conditioning units and in other noisy spots.
Zinc oxide is a piezoelectronic substance (piezo comes from the Greek "to squeeze"), meaning that when it is subject to mechanical strain, the symmetry of its component crystals is distorted and a polarization charge appears. Nanomaterials expert Steve Dunn of Queen Mary University of London and Imperial College photochemist James Durrant hypothesized that by using acoustic vibrations, they could induce tiny piezoelectric currents in zinc-oxide nanorods, and boost the cells’ electricity output. To test their idea, the researchers used computer speakers to play the music from their mobile phones and individual frequencies from a signal generator at volumes of about 75 dB—equivalent to a lively office.
They found that the device was 40–50% more efficient when particular types of music were played. “It quite liked Adele and AC/DC,” said Dunn, “but then Safa [Shoaee] played some Persian funk at it and it was really loving that!”
The researchers suggested that a similarly broad range of frequencies arise from many types of everyday noise, making their devices eventually feasible for use on laptops, public transport and near airports. But even with the 50% increase in efficiency, zinc-oxide cells only achieve 1.8% power-conversion efficiency and lag way behind crystalline silicon’s 10–20% standard.
The team’s research is published in Advanced Materials.