Quantum dots are a nanotech marvel with the potential to transform batteries, solar power and TV displays
If there’s one thing people hate about their cellphones, it’s the poor battery life. Last November, a study by one Android device maker revealed that 37 per cent of phone owners cited losing battery charge as their biggest frustration.
Dr. Doron Myersdorf is one of those people who dislike dead cellphone batteries. Rather than simply get annoyed like the rest of us, though, he’s decided to do something about it. By 2016, he says, he will have developed a battery that will charge in 30 seconds. “This hits a soft spot for everyone,” says the CEO and co-founder of StoreDot, a Tel-Aviv-based startup.
He’s using “quantum dots” − a type of semiconductor made from tiny nanoparticles that trap charges better than traditional semiconductors − to enhance the electric properties of electrons. In other words, the dots can help a battery charge far faster and keep that charge for longer.
Quantum dots were discovered in 1984, but it’s only now that researchers and technology firms are putting these tiny semiconductors to widespread use.
While the 30-second battery has received the most buzz − the company got “many millions of hits and tons of calls” after Myersdorf announced his plans in early April − these dots can also make television and mobile screens brighter, make solar power cheaper and allow doctors to see how cells travel in the human body.
These minuscule particles, 10,000 times thinner than a human hair, are grown in two ways. Most scientists take semiconductor material such as cadmium or silicon and manipulate it in a liquid solution to create nanoparticles. StoreDot, however, uses amino acids − the same organic peptides found in the human body − to create nanocrystals. The dots are then grown to different sizes and absorb and emit light depending on the size. “This allows someone to emit a very specific wavelength of light,” Myersdorf says.
The power of quantum dots lies in how they absorb light and colour, says Graham Carey, a PhD candidate at the University of Toronto who is using them to create more efficient solar cells. Currently, a solar cell turns about 10 per of the sunlight it captures into electricity. Because quantum dots absorb light so much better than other materials, such as the silicon used in solar cells today, it could be possible to get that number up to 50 per cent.
That kind of efficiency could take a while, though. He’s hoping to create a cell that will turn at least 15 per cent of sunlight into electricity within the next two years.
When he is ready to roll out his solar cells, they will likely be a lot cheaper than the alternative. Because these dots are so small, they don’t need the large solar rigs you see on roofs today. In fact, you’ll be able to just paint them on the top of your house. “It’s solar paint,” he says. “Slather it onto a surface and you’re good to go.”
Another advantage to these dots is how they emit colour. The larger the dot, the redder the light it emits; the smaller the dot, the bluer the hue.
Companies such as 3M, a St. Paul, Minn.-based global technology business, are creating different sizes of dots to put in LCD screens to enhance the range of colours that can be viewed on a screen. Right now, a typical TV or phone displays about 50 per cent of the colours the human eye can see. A quantum dot screen will display 75 per cent of those colours, says John van Derlofske, a senior research specialist at 3M’s Optical Systems Division Laboratory.
LCD screens have colour filters in them that turn on and off depending on what colour is needed, he explains. Quantum dots allow more light to pass through. “A very pure light goes through these colour filters and that enhances the colour that the display can show,” he says.
The future of dots
Consumers can already buy products with quantum dots in them, such as Sony’s W900A television, but Richard Lunt, an assistant professor at Michigan State University, says many more products will incorporate nanoparticles in the future.
Researchers are still trying to figure out how to produce them on a mass scale, what sizes yield the best results and how to ensure they stay stable; if they’re not manufactured properly they can become less bright, less conductive and lose their colour, says Lunt. However, the “advances are exciting enough to outweigh the issues that still linger,” he says.
In the future, these dots will be used in medical imaging for clearer and brighter resolution. It may also be possible to inject them into patients and track where they travel − the bright colours will make it easy to see their path. They could also make light bulbs brighter and cameras better, adds Carey.
Myersdorf hopes to not just improve cellphone batteries, but also the memory and display. “We’re creating a new type of electrode from scratch that can have applications all over the place,” he says, adding that he thinks he may even be able to power an electric car, such as the Tesla, in 30 seconds too.
It will still be awhile before the 30-second charge becomes a reality. While his battery can charge that quickly now, it’s much larger than a normal battery and only lasts a third of the time. However, he thinks it could be ready in two years. It has to be, says Myersdorf. Battery life shouldn’t stay this poor forever.
“This is a solution everyone wants,” he says. “It’s what people are looking for and what we’re working on 24/7 to do.”
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