A group of scientists from the Queen Mary University of London and the Imperial College London have made quite an amazing discovery: solar cells like pop and rock music, but they’re not too keen on classical.
Obviously I am not talking about actual conscious preferences, but rather that by playing high pitched sounds, often found in pop and rock songs, the performance of the solar cells increased remarkably.
In their experiments the researchers grew tiny zinc oxide nanorods and then covered them with an active polymer that created a photovoltaic device to turn the suns light into electricity. The high frequencies and pitches in the songs played caused vibrations in the nanorods which increased the efficiency of the solar cells by 40%.
Zinc oxide is a well-known piezoelectric material, meaning that when a pressure or strain is applied it produces voltage. These experiments were designed to test the effect that this piezoelectric phenomena would have on solar cells. The results were very unexpected. (Related article: Ceramic Converter Tackles Solar Cell Problem)
Dr. Steve Dunn, from the Queen Mary’s School of Engineering and Materials Science, said that “after investigating systems for converting vibrations into electricity this is a really exciting development that shows a similar set of physical properties can also enhance the performance of a photovoltaic.”
James Durrant, the Professor of Photochemistry at Imperial College London, explained that they had “thought the sound waves, which produce random fluctuations, would cancel each other out and so didn't expect to see any significant overall effect on the power output.
The key for us was that not only that the random fluctuations from the sound didn't cancel each other out, but also that some frequencies of sound seemed really to amplify the solar cell output - so that the increase in power was a remarkably big effect considering how little sound energy we put in.
We tried playing music instead of dull flat sounds, as this helped us explore the effect of different pitches. The biggest difference we found was when we played pop music rather than classical, which we now realize is because our acoustic solar cells respond best to the higher pitched sounds present in pop music.”