Environment

Buddhist singing bowls could inspire highly efficient solar cells

Buddhist singing bowls could i...
Dr Niraj Lal says that the way Buddhist singing bowls interact with light mimics the way they capture sound
Dr Niraj Lal says that the way Buddhist singing bowls interact with light mimics the way they capture sound
View 1 Image
Dr Niraj Lal says that the way Buddhist singing bowls interact with light mimics the way they capture sound
1/1
Dr Niraj Lal says that the way Buddhist singing bowls interact with light mimics the way they capture sound

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."

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.

We saw the value of this approach earlier this year, when researchers produced a multi-material, four-junction, four-terminal stacked solar cell that achieved efficiencies of 43.9 percent.

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.

The team's research was published in the IEEE Journal of Photonics.

Source: Australia National University via Science in Public

9 comments
Onihikage
"Niraj [...] 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."
On the face of it, this sounds like it means 100% efficiency, which is obviously impossible. What is this quadruple boost relative to? What's the baseline that's being enhanced? I presume this really means the singing bowl design only loses 1/4 of the light that is lost to reflection in flat panes, which makes a lot more sense. For example, if a flat pane reflects 750 photons out of every 1000 that hit it, a pane with "singing bowl" cells would only reflect 188.
In other words, this has no bearing on the actual efficiency of the cell to convert absorbed photons into electrons, only on its efficiency in absorbing photons.
Steve Jones
I wonder if the same principle could be used to make camera pixels which trap more light.
JeffC
there are multiple ways to increase the amount of light that hits a solar cell ... nothing new here ...
KenCrawford
"there are multiple ways to increase the amount of light that hits a solar cell ... nothing new here ..."
Non-sequitur alert. That other ways exist in no way negates the usefulness of a new way. If we combine technologies, the overall efficiency may still be improved, a point already addressed by the author.
pmshah
Just wondering how the contraption would work if this "nano bowl" were to be at the bottom of the stack !
Daniel Gregory
I hear that zero light escapes a black hole...100% efficiency. Black holes also seem to be self-perpetuating.
moreover
At issue is the manufacturing process. Depending on the application an easily and cheaply printable PV cell of lower efficiency may make more sense.
redjeff53
why bother if it's 'nano scale?' if it can't be produced without some 'microscopic process' it will end up being 'too expensive' to be practical!
Lindsey Roke
" 'too expensive' to be practical"? It is not always true that the objective is maximum output per $. Sometimes it can be maximum output per square metre - as in solar racers - and probably satellites and some portable equipment. I wonder how much surface contamination (or even rain) might be a problem.