Buddhist Singing Bowl Resonates with Light
Tibetan, or Buddhist singing bowls are a unique type of bell that, according to Wiki, are called standing bells. These are bells that stand on one end and are vibrated by rubbing or striking the rim with a wrapped mallet. They usually vibrate at the fundamental frequency of the bell with one or two overtones. Singing bowls (also known as Tibetan Singing Bowls, rin gongs, Himalayan bowls or suzu gongs) are a type of bell, specifically classified as a standing bell. Rather than hanging inverted or attached to a handle, singing bowls sit with the bottom surface resting, and the rim of singing bowls vibrates to produce sound characterized by a fundamental frequency (first harmonic) and usually two audible harmonic overtones (second and third harmonic).http://en.wikipedia.org/w/index.php?title=Singing_bowl&oldid=625328564
A young scientist from Australia was inspired by the singing bells to use their design in a new type of solar cell and wrote his PhD thesis at the University of Cambridge on that subject. He has now done research on using this photonic resonance to increase the efficiency of solar panels. While the unique shape of Buddhist singing bowls is vital to the creation of their signature sound, a researcher from Australia National University (ANU) has used their design as the inspiration for a new breed of solar cells. In completing his PhD at the University of Cambridge, Dr Niraj Lal found that just as the bowls cause sound to resonate, miniaturized versions can be made to interact with light in much the same way, inspiring solar cells better able to capture sunlight.
ⓐPrevious research has established that light behaves differently when working at the nanoscale. Downsizing his bowl-inspired cells to this level, Lal, now working at ANU, was able to demonstrate a device with the ability to capture significantly more light and convert it to electricity.
ⓐ"Current standard solar panels lose a large amount of light-energy as it hits the surface, making the panels’ generation of electricity inefficient," says Niraj. "But if the cells are singing bowl-shaped, then the light bounces around inside the cell for longer."
This process is called plasmonic resonance and I first discussed this on my post about the Lycurgus cup. That cup had the property of plasmatic resonance and looked green in reflection and red in transmission of light. The Lycurgus Cup, The Rest Of The Story
posted to Materials Science on G+ August 27, 2013https://plus.google.com/117751903650439005786/posts/CPRuEMQqu68"Current standard solar panels lose a large amount of light-energy as it hits the surface, making the panels’ generation of electricity inefficient," says Niraj. "But if the cells are singing bowl-shaped, then the light bounces around inside the cell for longer."
ⓐNiraj calls this process "plasmonic resonance"" and says his nanobowls perform at four times the efficiency of flat solar cells in the lab, which when made from single materials such as silicon have an efficiency of 25 percent.
ⓐImprovements have been made on flat, single structure solar cells by way of tandem devices that stack a number of cells on top of each other. With the cells made from different materials, each with their own light absorption properties, the device is able to catch a wider range of the solar spectrum, enhancing its overall efficiency.
ⓐNiraj and his team are now exploring ways that the nanobowl design can be incorporated into these tandem structures. "If we can make a solar cell that ‘sees’ more colors and keeps the right light in the right layers, then we could increase efficiency even further," he says
ⓐIn research which will be published in the November issue ofIEEE Journal of Photonics, Niraj and his collegues have shown that by layering two different types of solar panels on top of each other in tandem, the efficiency of flat rooftop solar panels can achieve 30 per cent—currently, laboratory silicon solar panels convert only 25 per cent of light into electricity, while commercial varieties convert closer to 20 per cent.http://www.scienceinpublic.com.au/media-releases/solarbowl
What makes this really interesting is that we have full access to the PhD thesis of Niraj Narsey Lal at the University of Cambridge. If you are interested you can't get a more detailed explanation of this unique method of increasing solar panel efficiency that his thesis.
ⓐ GizmagBuddhist singing bowls could inspire highly efficient solar cellshttp://www.gizmag.com/buddhist-singing-bowl-solar-cell/33794/
ⓑ _Enhancing solar cells with plasmonic nanovoids_https://www.repository.cam.ac.uk/handle/1810/243864
Image: Figure 1.2 in the PhD Thesis of Dr Niraj Lal University of Cambridge