Upconverting Nanoparticles Working As Primary Thermometers In Different Media

authors	Balabhadra, S; Debasu, ML; Brites, CDS; Ferreira, RAS; Carlos, LD
nationality	International
journal	JOURNAL OF PHYSICAL CHEMISTRY C
keywords	LUMINESCENT NANOTHERMOMETERS; LIVING CELLS; TEMPERATURE; SENSITIVITY; EMISSION; GREEN
abstract	In the past decade, noninvasive luminescent thermometry has become popular due to the limitations of traditional contact thermometers to operate at scales below 100 mu m, as required by current demands in disparate areas. Generally, the calibration procedure requires an independent measurement of the temperature to convert the thermometric parameter (usually an intensity ratio) to temperature. A new calibration procedure is necessary whenever the thermometer operates in a different medium. However, recording a multiple calibrations is a time-consuming task, and not always possible to perform, e.g., in living cells and in electronic devices. Typically, a unique calibration relation is assumed to be valid, independent of the medium, which is a bottleneck of the secondary luminescent thermometers developed up to now. Here we report a straightforward method to predict the temperature calibration curve of any upconverting thermometer based on two thermally coupled electronic levels independently of the medium, demonstrating that these systems are intrinsically primary thermometers. SrF2:Yb/Er powder and water suspended nanoparticles were used as an illustrative example.
publisher	AMER CHEMICAL SOC
issn	1932-7447
year published	2017
volume	121
issue	25
beginning page	13962
ending page	13968
digital object identifier (doi)	10.1021/acs.jpcc.7b04827
web of science category	Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary
subject category	Chemistry; Science & Technology - Other Topics; Materials Science
unique article identifier	WOS:000404828600059