How quantum dots supercharge farming, medicine and solar, too

What if you could grow vegetables in half the time? What if a surgeon could see cancerous cells throughout an entire operation? What if solar panels could become significantly cheaper and easier to make?

All of these improvements and more could come in the near future, thanks to the same tech that helps your TV create lavish and realistic colors. Quantum dots in TVs increase efficiency, create wider color gamuts and improve light output, and soon they'll improve image quality even more.

But that's just the beginning. From medicine to agriculture to solar energy, quantum dots have the potential to change industries far beyond your television set. 

What's a dot?

Quantum dots are microscopic molecules thousands of times smaller than the width of a human hair and hundreds of times smaller than a red blood cell. At that size, these molecules have some peculiar properties. Normally when we talk about quantum dots here at CNET, we're referring to their ability to emit very specific wavelengths of light when supplied with energy, improving the color and efficiency of televisions. That, and other unique properties, also make them the focus of a lot of truly futuristic research, as we'll explore below.

Quantum dots that emit visible wavelengths of light are in the 2-to-10-nanometer rage. Larger quantum dots, up to 100nm, are typically referred to as nanocrystals.

The farm of the future is magenta

After the US, guess what country is the second largest exporter of food by dollar value? The Netherlands. One of the smallest countries in the world has become one of the biggest exporters of food. 

Dutch farmers have become masters of indoor farming, as National Geographic reports. With advanced greenhouses using LED lights, hydroponics and more, they're able to grow more food, faster and in a smaller space. It's a growing trend (pun intended).

Lighting is one of the biggest costs of indoor farming, but some wavelengths (colors) of visible light are more useful than others. Magenta, for example, is a favorite of green plants. Quantum dots can be tuned to produce magenta light efficiently. 

By using wavelengths the plants want most, less overall light and power needs to be used. No power is wasted creating green wavelengths that a specific plant species doesn't need, for example. 

Lights augmented by quantum dots can promote faster growth, not just on a per-plant basis, but even depending on where that plant is in its growing cycle. Certain wavelengths can be used for a young plant, and slightly different wavelengths for a more mature plant. 

Researchers have also been able to grow plants faster. Nanoco, makers of the lights you see in the image at the right and above, claim that in some cases plants can grow twice as fast as with standard LED lights. 

Quantum dots could be the key to indoor farms producing significantly more food, or small farms being able to produce vastly more food. Indoor farms can also exist in places not typically conducive to farming, such as the cities where most of the world now lives.

And if you look even further ahead, this would be a pretty fantastic way for us to grow a lot of food quickly in space, on the Moon or Mars, and beyond. 

Killing cancer with light

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Quantum dots, and the broader category of nanoparticles, are helping researchers from places like the Sanford Burnham Prebys Medical Discovery Institute, universities as far-ranging as India and Italy, companies like Dotz Nano  and more, find and attack cancer in two ways. 

The first is what's called "in vivo" imaging. If your Latin's rusty, that means "in living," which is to say it's a way to see what's going on inside your body. There are currently lots of ways to do this, from x-rays to CT scans and MRIs, but quantum dots add a fascinating twist.

By binding quantum dots to your body's immune cells, doctors can track where those cells are attacking most, i.e. the tumor itself. Using the QD's light-emitting properties, this can make the cancer cells literally glow, aiding in diagnosis and treatment, including surgery. There are other ways for QDs to "find" cancer cells as well, but more importantly, this glow effect lasts longer than traditional marking dyes: several hours compared to a few minutes. This would let a surgeon see the tumor throughout a surgery, not just for a few minutes at a time. 

Making tumors easier to see is currently a huge part of medical research. Another futuristic material scientists are looking to use is graphene, which is a single layer of carbon atoms that can make certain cancers glow.

The second way quantum dots can help is by helping to attack the cancer itself, as described in the video above. By attaching treatment chemicals to the nanoparticles, doctors can target the cancer far more precisely. Send in nanoparticles that are dosed up with anticancer treatments and they only stick where there's cancer. Give them a burst of energy that's otherwise harmless to humans, and the nanoparticles explode, releasing their medications right where it's needed and only where it's needed. This means the cancer gets a higher dose, but the overall dose to the patient is lower. Better results, fewer side effects.

Other researchers are looking at ways that quantum dots and other nanoparticles can help with Alzheimer's, diabetes and more. The University of Colorado Boulder, for instance, has found that quantum dots can improve the effectiveness of antibiotics in certain situations by 1,000 percent.

Powered by the sun

Researchers from places like the Los Alamos National Laboratory and University College London, companies like Solterra and UbiQD, and many others are using quantum dots to help improve the efficiency of solar power.

Though it's not quite as simple as "TV, but backwards" it's possible to create a solar cell that uses quantum dots. So instead of taking electricity and creating light, like they do on a TV, they take light and create electricity. Although still very early in development, researchers expect to get quantum dot-based solar cells to be at least as efficient, and likely more so, than a traditional solar cell.

There are two big benefits for using quantum dots for solar. One, quantum dots can be tuned to react to different wavelengths of light, absorbing light in a wider range than traditional solar cells, including infrared and ultraviolet. This would, in theory, allow them to create electricity, more efficiently, for more hours each day… and even at night.  

The far greater benefit is cost. Relatively inexpensive printable solar cells could be put anywhere and everywhere. While there are a few solar battery packs for smartphones now, they take far too long to charge and only work in strong direct sunlight. Imagine a phone of the future that could recharge anywhere, anytime, just by flipping it over onto its back and absorbing the light from wherever you are. It wouldn't even look like a traditional "solar panel."  

And that's just the beginning. How about windows that create electricity? Instead of windows that block UV light to protect your belongings from fading, imagine windows that convert UV light to help power your house.

Windows, of course, are just part of the walls of your house and car. So how about electricity-producing paint? Skip the solar "cells" completely and just have every surface of your house or car create power. This has been on the horizon for a few years, but since QDs in general are getting cheaper, it's getting there.

In the intermediate time frame, another method uses quantum dots to change the wavelengths of incoming light, changing the light's color so to speak, to wavelengths more readily absorbed by traditional solar cells. It would be a small increase in the cost of said cells, but a significant increase in potential performance. The Center for Advanced Solar Photophysics at Los Alamos thinks this could improve efficiency of the panels by 34 percent for about $10 increase in cost. 

Of course, it's not like traditional silicon-based solar is just sitting around waiting for quantum dots to take over. That industry too is looking to shrink things down to the nano-scale, with nanophotronics. This essentially makes the solar cells thinner, more efficient for their size, and cheaper to manufacture. A team at MIT is looking to use nanotubes to convert light into heat, and then into electricity. 

The advantage of thermophotovoltaics, they claim, is that it's easier to store heat than electricity, and the light they create can be better tuned to work with solar cells. As MIT Technology Review encapsulates it: "Because heat is easier to store than electricity, it should be possible to divert excess amounts generated by the device to a thermal storage system, which could then be used to produce electricity even when the sun isn't shining." Sounds promising indeed.

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Tiny, but big

We've talked for years about how cool quantum dots are for TVs . This same tech might one day help reduce hunger, save lives, even power our cars and devices while potentially reducing greenhouse gas emissions. 

And these are just a few of the highlights. Countless other uses are being researched by hundreds of companies around the world. 

It's remarkable to think these microscopic molecules, hundreds of times smaller than cells in your body, will have a big role to play now and in future.

Got a question for Geoff? First, check out all the other articles he's written on topics like why all HDMI cables are the same, TV resolutions explained, LED LCD vs. OLED and more. Still have a question? Tweet at him @TechWriterGeoff then check out his travel photography on Instagram. He also thinks you should check out his best-selling sci-fi novel and its sequel.