Luminescent Glow Measures Temperature

Portuguese and Spanish researchers have teamed up to create bimetallic lanthanide-based luminescent materials that can function as a high-precision nanothermometer for monitoring objects that are typically too small or too hard to reach using conventional temperature sensors (Adv. Mater., DOI: 10.1002/adma.201001780). Luís D. Carlos of Portugal’s University of Aveiro, Fernando Palacio of Spain’s University of Zaragoza, and coworkers made the materials by embedding terbium and europium diketonate complexes in a diureasil polymer or in nanoclusters formed from an iron oxide magnetic core coated with an organosilica shell. Temperature-dependent changes in the intensity of the terbium complex’s green luminescence and the europium complex’s red luminescence make it possible to use the materials to measure temperatures from 10 to 350 K. The team tested the material by depositing a layer of polymer on the surface of an integrated circuit and then using an optical fiber to excite the layer and detect the emission spectrum. In this way, the researchers were able to map out the hotter and cooler portions of the circuit. Palacio believes the nanoparticle's luminescent properties coupled with its magnetic properties will be ideal for noninvasive diagnostic testing, such as mapping tumors via their cellular temperature distributions or tracking biochemical processes occurring within cells.