Scientists have recently made an exciting discovery regarding a nanoscale material that changes color with temperature variations.
Researchers at the University of California, Irvine have identified a one-dimensional nanoscale material whose color shifts as the temperature alters. This important discovery was published in Advanced Materials.
“We have developed very small and highly sensitive thermometers,” stated Maxx Arguilla, a chemistry professor at UC Irvine and the leader of the research team. “This is one of the most practical and applicable projects to emerge from our lab.”
Arguilla compared these new thermometers to “nano-scale mood rings,” highlighting how these rings change color in response to a person’s body heat. However, unlike the rings that provide only a qualitative temperature indication, the color alterations in these materials can be calibrated for precise optical temperature measurements at the nanoscale, Arguilla emphasized.
“Monitoring temperature is crucial, as numerous biological and industrial processes are reliant on tracking slight temperature fluctuations,” he noted. “We could now potentially use these thermometers to probe into cells.”
Dmitri Cordova, a postdoctoral researcher in Arguilla’s group, added that these optical thermometers might also measure temperatures and evaluate the performance of micro- and nano-electronics, including circuits and storage devices. Although industries currently use optical thermometers for computer component manufacturing, Cordova pointed out that this new material is “at least ten times more sensitive.”
The team achieved this breakthrough after growing crystals in their lab, which at the nanoscale, resemble helical “slinkies.” They initially cultivated these crystals to subject them to heat stress and observe the temperatures at which the crystals would break down.
Cordova and undergraduate researcher Leo Cheng noticed that the crystals’ colors transitioned systematically from yellow to orange as the temperature rose.
Following this, the team conducted meticulous measurements of the temperature ranges that corresponded to specific colors, finding that light yellow indicated a temperature close to -190 degrees Celsius, while red-orange colors were linked to around 200 degrees Celsius.
“We dedicated considerable effort to ensure that our measurements were accurate,” remarked Arguilla.
To obtain nanoscale samples, the researchers applied a piece of adhesive tape to the larger crystals, lifted it off, and transferred the nanoscale fragments that adhered to the tape onto clear substrates.
“These structures can be peeled away and used as nanoscale thermometers that are transferable, reconfigurable, and compatible with other materials or surfaces,” Arguilla explained.
He mentioned that this discovery represents the initial step towards finding new materials capable of measuring temperatures at the nanometer scale.
In the future, his lab aims to explore other nanomaterials to create thermometers that can measure a broader temperature spectrum.
“We are currently working to manipulate the material design processes to produce even more sensitive sensors,” Arguilla said. “Our goal is to broaden the scope of optical thermometry from bulk scales down to the nanoscale.”
Co-authors of the study include Yinong Zhou, Griffin M. Milligan, Leo Cheng, Tyler Kerr, Joseph Ziller, and Ruqian Wu. This research received financial support from the National Science Foundation via the UC Irvine MRSEC, Center for Complex and Active Materials (Award No. DMR-2011967).
