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Cryogenic Luminescent Ratiometric Thermometers Based on Tetragonal Na[LnSiO 4 ]·xNaOH (Ln = Gd, Tb, Eu; x ≈ 0.2)
Author(s) -
Ananias Duarte,
Mongis Camille M.,
Carlos Luís D.,
Rocha João
Publication year - 2020
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.202000057
Subject(s) - tetragonal crystal system , chemistry , luminescence , photoluminescence , hydrothermal circulation , powder diffraction , crystallography , spectroscopy , scanning electron microscope , analytical chemistry (journal) , hydrothermal synthesis , crystal structure , materials science , optoelectronics , chemical engineering , physics , chromatography , quantum mechanics , engineering , composite material
The hydrothermal synthesis under mild conditions and structural characterization of Na[LnSiO 4 ] · xNaOH (Ln = Gd, Tb, Eu; x ≈ 0.2) are reported. These materials crystallize in the tetragonal non‐centrosymmetric I4 – space group. The crystal phase purity is ascertained by powder X‐ray diffraction and scanning electron microscopy, and further confirmed by photoluminescence spectroscopy and lifetime measurements at 294 and 12 K. Na[(Gd 0.82 Tb 0.14 Eu 0.04 )SiO 4 ] · xNaOH and Na[(Gd 0.66 Tb 0.30 Eu 0.04 )SiO 4 ] · xNaOH perform well as visible ratiometric thermometers, based on the ratio between the Tb 3+ and Eu 3+ emissions, presenting good relative thermal sensitivities at cryogenic temperature (<100 K) with maxima of 1.9 %K –1 at 14 K and 6.2 %K –1 at 12 K, respectively.