title: Optimization of highly sensitive YAG:Cr3+,Nd3+nanocrystal-based luminescent thermometer operating in an optical window of biological tissues.
abstract: Luminescent and temperature sensitive properties of YAG:Cr3+,Nd3+nanocrystals were analyzed as a function of temperature, nanoparticle size, and excitation wavelength. Due to numerous temperature-dependent phenomena (e.g. Boltzmann population, thermal quenching, and inter-ion energy transfer) occurring in this phosphor, four different thermometer definitions were evaluated with the target to achieve a high sensitivity and broad temperature sensitivity range. Using a Cr3+to Nd3+emission intensity ratio, the highest 3.48% K-1sensitivity was obtained in the physiological temperature range. However, high sensitivity was compromised by a narrow sensitivity range or vice versa. The knowledge of the excitation and temperature susceptibility mechanisms enabled wise selection of the spectral features found in luminescence spectra for a temperature readout, which enabled the preservation of relatively high temperature sensitivity (>1.2% K-1max) and extended the temperature sensitivity range from 100 K to 850 K. The size of the nanophosphors had negligible impact on the performance of the studied materials.
authors.affiliation: Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wroclaw, Poland. l.marciniak@int.pan.wroc.pl.
authors.forename: L
authors.identifier: http://orcid.org/0000-0001-5181-5865
authors.initials: L
authors.lastname: Marciniak
authors.affiliation: Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wroclaw, Poland. l.marciniak@int.pan.wroc.pl.
authors.forename: A
authors.identifier: http://orcid.org/0000-0003-4113-0365
authors.initials: A
authors.lastname: Bednarkiewicz
authors.affiliation: Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wroclaw, Poland. l.marciniak@int.pan.wroc.pl.
authors.forename: J
authors.initials: J
authors.lastname: Drabik
authors.affiliation: Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wroclaw, Poland. l.marciniak@int.pan.wroc.pl.
authors.forename: K
authors.initials: K
authors.lastname: Trejgis
authors.affiliation: Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wroclaw, Poland. l.marciniak@int.pan.wroc.pl.
authors.forename: W
authors.initials: W
authors.lastname: Strek
mesh_terms: D000535:Aluminum / Q000737:chemistry*; D002857:Chromium / Q000737:chemistry*; D008163:Luminescent Measurements; D053758:Nanoparticles / Q000737:chemistry*; D009354:Neodymium / Q000737:chemistry*; D010316:Particle Size; D013696:Temperature; D014961:X-Ray Diffraction; D015019:Yttrium / Q000737:chemistry*
chemical_list: C503779:yttrium-aluminum-garnet; D002857:Chromium; D009354:Neodymium; D015019:Yttrium; D000535:Aluminum