Brandeis Stories

By David Levin
March 5, 2026 • Science and Technology

To see new quantum technology at work, you won't need to visit a high-tech lab. A Costco will do.

Walk down the television aisle, and you'll see screens the size of dining room tables, all displaying impossibly vivid colors — deep blues, brilliant greens, saturated reds. In many cases, these images are made possible by millions of tiny crystals called "quantum dots," semiconductors that act like tiny, precise LED lights.

Each of these nanocrystals is smaller than a virus, but together, they represent a sea change in display technology. Traditional LEDs require different materials for each color. Quantum dots, on the other hand, use a single material that's relatively easy to make and extremely adaptable. Simply change the size of a quantum dot crystal, and the color it emits will change as well. Make one small and it glows blue. Let it grow larger and it shifts to red. Either way, the chemical makeup stays exactly the same.

That color-tuning trick has been good enough to sell TVs. But Katie Shulenberger, assistant professor of chemistry at Brandeis, is more interested in what's been holding quantum dot technology back. The big advances that these tiny structures could enable — like color-tunable lasers, high-powered solar cells or photocatalysts that convert sunlight directly into chemical fuels — remain stubbornly out of reach until researchers can figure out how to make the crystals more efficient.

Shulenberger thinks part of the issue is that scientists have been going about their work from the wrong angle. At the moment, most measurement techniques involve suspending crystals in a fluid or spreading them thinly in a grid and parking a microscope on individual quantum dots for an hour at a time.

"You're sitting in a microscope and you're saying, look at all these nanocrystals. Ooh, that one looks really bright. Let's sit and look at that one," Shulenberger says. "You end up cherry-picking the best performers from a sample, so you're only looking at 200 of the best, brightest of the 10,000."

Instead of taking each dot in isolation, Shulenberger says, she wants to study how they act while crammed together on a sheet, the same way they'd be situated in a commercial environment. Measuring how those crystals interact on an atomic level could provide critical information for making quantum dots more effective, she notes — but it's not exactly easy.

On the inside of a nanocrystal, atoms bond to their neighbors in a regular pattern. On the outer edge of the crystal, however, atoms don't have a neighbor on one side, so miss out on some of those bonds, Shulenberger says. The missing bonds create defects where electrons can get stuck or energy can be lost, introducing small flaws that sabotage efficiency. "We're talking about the bonds around one atom in a thousand," she adds — but when multiplied over billions of crystals, these defects add up, creating wasted energy in the form of heat.

To get around this problem, Shulenberger is developing techniques to study quantum dots not as isolated particles, but as assemblies of atoms with surfaces, interfaces and defects.
Her latest advance helps to calculate the average behavior of quantum dots that are packed together on a sheet. Instead of choosing them by eye under a microscope, she's developed a technique that randomly samples a few hundred dots out of many thousands, providing data with no selection bias or artificially optimistic results.

While it may not sound dramatic, her work could matter a lot for getting quantum dots into applications beyond TV screens. Eventually, they could power solar concentrators that focus light onto small cells to boost efficiency; lasers that can be tuned to any color researchers need; or even provide photocatalysts that can make ammonia — a fertilizer whose industrial production eats up a staggering amount of global energy — directly from sunlight.

Shulenberger is interested in the gap between what these materials can already do, and what they could achieve if researchers understood and controlled their surfaces better. "I find the weeds so interesting that sometimes it's hard for me to step away from that, because I love the nuance and the detail and the technical pieces," she says.

In this case, staying in the weeds could determine whether quantum dots transform energy production and chemical manufacturing, or remain a display technology. For technology built on crystals just nanometers across, it seems, tiny details could have a massive impact.