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Correlation Between Photoluminescence and Structural Defects in Ca 1+ x Cu 3 − x Ti 4 O 12 Systems
Author(s) -
Oliveira Larissa H.,
Paris Elaine C.,
Avansi Waldir,
Ramirez Miguel A.,
Mastelaro Valmor R.,
Longo Elson,
Varela José A.
Publication year - 2013
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.12020
Subject(s) - orthorhombic crystal system , photoluminescence , xanes , materials science , crystallography , rietveld refinement , powder diffraction , x ray crystallography , spectroscopy , analytical chemistry (journal) , absorption spectroscopy , crystal structure , diffraction , chemistry , physics , quantum mechanics , optics , optoelectronics , chromatography
Ca 1+ x Cu 3 − x Ti 4 O 12 powders were synthesized by a conventional solid‐state reaction. X ‐ray diffraction ( XRD ) was performed to verify the formation of cubic CaCu 3 Ti 4 O 12 ( CCTO ) and orthorhombic CaTiO 3 ( CTO ) phases at long range. Rietveld refinements indicate that excess Ca atoms added to the Ca 1 − x Cu 3 − x Ti 4 O 12 ( x = 1.0) composition segregated in a CaTiO 3 secondary phase suggesting that solubility limit of Ca atoms in the CaCu 3 Ti 4 O 12 lattice was reached for this system. The FE‐SEM images show that the Ca 1+ x Cu 3 − x Ti 4 O 12 (0 < x < 3) powders are composed of several agglomerated particles with irregular morphology. X ‐ray absorption near‐edge structure spectroscopy ( XANES ) spectra indicated [ TiO 5 V o z ]‐[ TiO 6 ] complex clusters in the CaCu 3 Ti 4 O 12 structure which can be associated with oxygen vacancies (V o z = V o x , V o • , and V o •• ) whereas in the CaTiO 3 powder, this analysis indicated [ TiO 6 ]–[ TiO 6 ] complex clusters in the structure. Ultraviolet‐visible ( UV –vis) spectra and photoluminescence ( PL ) measurements for the analyzed systems revealed structural defects such as oxygen vacancies, distortions, and/or strains in CaCu 3 Ti 4 O 12 and CaTiO 3 lattices, respectively.