Sensitive Thermochromic Behavior of InSeI
Optical thermometry measures temperature using the optical properties of materials, such as luminescence, absorbance, or fluorescence. In a study published in Advanced Materials, the seed team led by Assistant Prof. Maxx Q. Arguilla of Chemistry, along with co-workers Dmitri Leo Mesoza Cordova, Yinong Zhou, Griffin M. Milligan, Leo Cheng, Tyler Kerr, Joseph Ziller, and Prof. Ruqian Wu, demonstrated that the one-dimensional van der Waals solid InSeI, consisting of weakly interacting chains with a unique helical structure, exhibits a strong thermochromic response in the visible region.
This helical crystal, owing to its van der Waals nature, can be exfoliated into thin nanowire bundles. Temperature-dependent in-situ measurements of absorbance band edges revealed that the sensitivity of the thermal response of InSeI is 1.26×10−3 eV/K, a value appreciably higher than most dense conventional semiconductors in the visible range and comparable to soft lattice solids. Combined with its intrinsic exfoliability, this makes InSeI a strong candidate for optical nanothermometry applications.