Scientists Create Material That Can Withstand Temperature of Nanoscale Objects

Scientists at the University of California, Irvine, have discovered a one-dimensional nanoscale material that changes color as the temperature changes. The team’s findings are published in Advanced materials.

“We found that we could make very small, very sensitive thermometers,” said Maxx Arguilla, a professor of chemistry at the University of California, Irvine, whose research group led the study. “This is some of the most applied and translatable work to come out of our lab.”

Arguilla likened the thermometers to “nanoscale mood rings,” referring to jewelry that changes color based on the wearer’s body temperature. But instead of simply taking a qualitative temperature measurement, the color changes in these materials “can be calibrated and used to take optical temperature measurements at the nanoscale,” Arguilla said.

“It’s important to measure temperature because many biological and industrial processes depend on measuring tiny changes in temperature,” he added. “We now have thermometers that we could try to insert into cells.”

Optical thermometers can also measure temperatures and assess the efficiency of micro- and nanoelectronics, including circuits and data storage devices, according to Dmitri Cordova, a postdoctoral researcher in Arguilla’s group. Industries already have optical thermometers that they use to make computer components, but the new material the team developed is “at least an order of magnitude more sensitive,” Cordova said.

The breakthrough came when Cordova and his colleagues grew crystals in their lab that, at the nanoscale, resemble helical “slinkies.” They first grew the crystals so they could subject them to heat stress to see at what temperature they would disintegrate.

Cordova and undergraduate researcher Leo Cheng noticed that the colors of the crystals consistently shifted from yellow to orange, depending on the temperature.

The team then took precise measurements of the temperature range that the colors corresponded to, and found that light yellow colors corresponded to temperatures around -190 degrees Celsius, while red-orange colors corresponded to temperatures around 200 degrees Celsius.

“We put a lot of effort into ensuring that the measurements were accurate,” Arguilla said.

To retrieve nanoscale samples of the material, the lab stuck a piece of adhesive tape to volume-scale crystals, removed it, and transferred the nanoscale samples stuck to the tape to transparent substrates.

“We can peel these structures off and use them as nanoscale thermometers that can be transferred, reconfigured and coupled to other materials or surfaces,” Arguilla said.

Arguilla explained that this discovery is the first step towards discovering new classes of materials that can take temperature measurements at the nanoscale.

Next, his lab plans to test other nanoscale materials to see if it’s possible to develop thermometers that can measure a wider temperature range.

“We are now trying to change the rules of material design to create even more sensitive materials,” Arguilla said. “We are trying to open up the toolbox of optical thermometry, from the volume scale to the nanoscale.”

Co-authors include Yinong Zhou, Griffin M. Milligan, Leo Cheng, Tyler Kerr, Joseph Ziller, and Ruqian Wu.