Golden innovation shines light on solar possibilities

Paul Mayne // Western News

Physics and Astronomy professor Giovanni Fanchini’s research surrounding gold nanoclusters has the potential to decrease dramatically dependence on traditional resource-based sources of energy by increasing solar cell performance by more than 10 per cent.

Giovanni Fanchini knows a ‘golden’ discovery when he finds one. And this may just lead to a more sustainable future.

The Physics and Astronomy professor’s research centres on the construction small molecules – each one created from 144 atoms of gold. (For scale, that’s about 100,000 times smaller than a human hair.) Thousands upon thousands of those molecules are then arranged into nanoclusters – extremely small, well-ordered and uniformed-sized metal formations.

By using these nanoclusters, Fanchini has shown the ability to increase solar cell performance by more than 10 per cent. That number represents the potential to take solar power mainstream.

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His findings were published recently in the journal Nanoscale.

“Every time you recharge your cell phone, you have to plug it in,” said Fanchini, the Canada Research Chair in Carbon-based Nanomaterials and Nano-optoelectronics. “What if you don’t find a plug? What if you could charge mobile devices, like phones, tablets or laptops, on the go? We have a giant plug right above us.

“Not only would it be convenient, but the potential energy savings would be significant.”

The secret is in the fact the spectrum of light reflected by gold matches the spectrum of light from the sun, Fanchini said. His gold nanoclusters then amplify the amount of sunlight going directly into the device.

“What colour is gold? And what colour is the sun?” Fanchini asked. “Picture an extremely delicate fishnet of gold. The fishnet catches the light emitted by the sun and draws it into the active region of the solar cell.”

Previous research has proven larger gold nanoparticles can enhance solar cell performance. But the cost for application was too prohibitive.

Copper nanoclusters are another possibility in the process – and perhaps more attractive given the source material would be much cheaper. However, copper oxidizes easily and repetitive replacement of an entire device would not be financially viable.

Gold does not oxidize. And while one ounce of gold is going for almost $1,500, the amount used is so small the cost difference would be less than a penny on the dollar.

“We have very little gold inside, so the impact on the total cost of the device is negligible. That’s the great thing about this,” Fanchini said.

Building on previous research, Fanchini’s team is getting results with infinitely small amounts of gold – approximately 10,000 times less than previous studies.

“You need to organize these small clusters in an efficient way on the solar face of the solar cells. We make a network with these nanoclusters and organize them in chains. Within each chain is a branch of a bigger network. We have a solution that is extremely flexible because we can use it on virtually any type of solar cell.”

Fanchini is encouraged by what his team has accomplished, but it’s just the tip of the beginning. Solar energy needs to reach an overall efficiency rate of at least 40 per cent to be competitive with oil – and the technology is only halfway there.

“We have all this renewable energy at our fingertips, but humankind is unbelievably blind. There is so much more can – and need – to use,” he said. “We’re not even close. The sun is unlimited and will always shine. It’s free. It’s only about the technology we have to be able to use it the best.

“We need to have a world in which the resources can be used indefinitely, otherwise our civilization will die off.”

Fanchini hopes to see his invention integrated into prototypes panels in one to two years and in solar-powered phones in as little as five.