Scientists at the University of California, Irvine have found a one-dimensional nanoscale substance whose color varies with temperature. The team's findings can be found in Advanced Materials.

Under the direction of UC Irvine professor of chemistry Maxx Arguilla, the study's research team said that they had figured out how to make incredibly small and sensitive thermometers. He went on to remark that it was one of the most versatile and practical inventions from their lab.

The jewelry that changes color based on the wearer's body temperature is called "nano-scale mood rings," and Arguilla compared the thermometers to this type of jewelry. However, Arguilla noted that these materials' color shifts can be calibrated and utilized to optically measure temperature at the nanoscale rather than only providing a qualitative temperature reading.

Dmitri Cordova, a postdoctoral researcher in Arguilla's group, asserts that the optical thermometers can also be used to measure the temperature and performance of micro- and nano-electronic circuits and data storage devices. Although Cordova claims that the team's new material is "at least an order of magnitude further sensitive," optical thermometers are already used by the computer component industry.

The discovery was made by Cordova and associates when they cultured crystals in their lab that, on nanoscale length scales, resemble helical "slinkies." Initially, the crystals were grown so that they could be exposed to heat stress and determine the temperatures at which they disintegrated.

Cordova and Leo Cheng, an undergraduate researcher, observed that the crystals' hues consistently changed with temperature, going from yellow to orange.

Following that, the researchers measured the exact temperature range to which each color correlated. They discovered that reddish-orange hues connected to temperatures around 200 degrees Celsius and bright yellow colors to temperatures around -190 degrees Celsius.