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Near‐Infrared Ratiometric Luminescent Thermometer Based on a New Lanthanide Silicate
Author(s) -
Ananias Duarte,
Almeida Paz Filipe A.,
Carlos Luís D.,
Rocha João
Publication year - 2018
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201802219
Subject(s) - lanthanide , triclinic crystal system , luminescence , silicate , materials science , crystallography , infrared , crystal structure , analytical chemistry (journal) , octahedron , atmospheric temperature range , chemistry , ion , optics , physics , optoelectronics , organic chemistry , meteorology , chromatography
A new lanthanide silicate system, Na 2 K[Ln 3 Si 6 O 18 ] (Ln=Lu, Yb/ Er, Lu/Eu, or Lu/Yb/Er), comprising microcrystals embedded in an amorphous siliceous matrix, obtained by sintering at 1373 K a Na 3 K[Ln 2 Si 6 O 17 ]⋅3 H 2 O nano‐crystalline precursor, is reported. The crystal structure of these lanthanide silicates was solved from high‐resolution synchrotron power X‐ray diffraction data collected at 110 K, and further supported by 29 Si MAS NMR and Eu 3+ luminescence. The materials crystallize in the P ī triclinic centrosymmetric space group, exhibiting a dense framework consisting of hexameric [Si 6 O 18 ] 12− cyclosilicate units, and chains of two distinct {LnO 6 } octahedra. Na 2 K[(Lu 0.75 Yb 0.20 Er 0.05 ) 3 Si 6 O 18 ] is the first example of a lanthanide silicate operative as a near‐infrared ratiometric luminescent thermometer, with good sensitivity at cryogenic temperatures (<100 K). Upon excitation at 903 nm, the ratio between the 2 F 7/2 → 2 F 5/2 (Yb 3+ ) and 4 I 13/2 → 4 I 15/2 (Er 3+ ) emissions was used for sensing temperature in the 12–450 K range, reaching a maximum thermal sensitivity of 2.6 % K −1 at 26.8 K.