Chemists could yield future devices such as next-gen displays and solar cells — ScienceDaily

Today, you can carry an entire computer in your pocket because technological building blocks from the 1950s are becoming smaller and smaller. But in order to create future generations of electronics – such as more powerful phones, more efficient solar panels or even quantum computers – scientists will need to come up with completely new technologies on the smallest scale.

One area of ​​interest is nanocrystals. These tiny crystals can assemble themselves into a variety of configurations, but scientists found it difficult to figure out how to get them to talk to each other.

A new study represents a breakthrough in making nanocrystals function together electronically. Posted on March 25th science, research could open the door to future devices with new capabilities.

“We call these high-volume building blocks because they can provide new capabilities – such as allowing cameras to see in the infrared,” said University of Chicago professor Dmitry Talapin, author of the article. “But so far it has been very difficult to put them together in a structure and let them talk to each other. Now for the first time we don’t have to choose. It’s a transformative improvement. “

In their work, the scientists set out design rules that should allow for the creation of many different types of materials, said Josh Portner, Ph.D. a chemistry student and one of the first authors of the study.

A small problem

Scientists can grow nanocrystals from many different materials: metals, semiconductors and magnets will have different properties. But the trouble was that every time they tried to put these nanocrystals together into arrays, new supercrystals grew with long “hairs” around them.

These hairs made it difficult for electrons to jump from one nanocrystal to another. Electrons are messengers of electronic communication; their ability to move easily is a key part of any electronic device.

The researchers needed a method of reducing the hairs around each nanocrystal so they could wrap them more tightly and reduce the gaps between them. “If these gaps are only three times smaller, the probability of an electron jump is about a billion times higher,” said Talapin, Honored Professor of Chemistry and Molecular Engineering in Chicago and senior scientist at Ernest David Burton. Argon National Laboratory. “With distance it changes a lot.”

To shave their hair, they sought to understand what was going on at the atomic level. To do this, they needed the help of powerful X-rays at the Center for Nanoscale Materials in Argon and the Stanford Synchrotron Radiation Light Source at the National SLAC Accelerator Laboratory, as well as powerful simulations and models of chemistry and physics in the game. All this allowed them to understand what is happening on the surface – and find the key to using their production.

Part of the process of growing supercrystals is carried out in solution – that is, in a liquid. It turns out that as the crystals grow, an unusual transformation occurs, in which the gas, liquid and solid phases coexist. By precisely controlling the chemistry of this stage, they could create crystals with a firmer, thinner appearance that could be packed together much more tightly. “Understanding their phase behavior was a significant step forward for us,” Portner said.

The full range of applications remains unclear, but scientists can come up with several areas where technology can lead. “For example, perhaps every crystal can be a qubit in a quantum computer; the combination of qubits into arrays is one of the fundamental problems of quantum technology right now, ”Talapin said.

Portner is also interested in studying the unusual intermediate state of matter observed during the growth of supercrystals: “Such a three-phase coexistence is quite rare, it is interesting to think about how to use this chemistry and create new materials.”

The study included scientists from the University of Chicago, Dresden University of Technology, Northwestern University, Arizona State University, SLAC, Lawrence Berkeley National Laboratory and the University of California, Berkeley.

The study was conducted in part at the Ministry of Economy’s Center for Advanced Materials for Energy and Water Systems, the Midwest Integrated Computing Materials Center, the Argon Nanoscale Materials Center and the Stanford Synchrotron Light Source at the National SLAC Accelerator Laboratory.

Funding: US Department of Energy, US Department of Defense, National Science Foundation, Arnold and Mabel Beckman Foundation, Alfred P. Sloan Foundation, David and Lucille Packard Foundation, Camille and Henry Dreyfus Teachers Award, Sherman Fairchild Foundation.


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