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Probing crystal structure and site‐selective photo‐physical properties of various Eu 3+ ‐doped niobates
Author(s) -
Phatak Rohan,
Pathak Nimai,
Muhammed Shafeeq,
Das Amitabh,
Sali Sanjay K.
Publication year - 2020
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.16953
Subject(s) - crystal structure , monoclinic crystal system , crystallography , phosphor , octahedron , photoluminescence , europium , ion , luminescence , emission spectrum , materials science , natural bond orbital , chemistry , analytical chemistry (journal) , spectral line , physics , computational chemistry , density functional theory , optoelectronics , organic chemistry , chromatography , astronomy
Niobates of the formula Ba 2 LaNbO 6 and BaLaM 2+ NbO 6 (M 2+ = Mg, Ca) were synthesized by the conventional solid state route. Size dependence of M‐cation on the bulk crystal structure of BaLaM 2+ NbO 6 was studied and compared with the Ba 2 LaNbO 6 compound. X‐ray diffraction study confirmed that BaLaMgNbO 6 compound has the rhombohedral ( R 3 ¯ ) crystal structure as compared to the monoclinic (I2/m) in BaLaCaNbO 6 and Ba 2 LaNbO 6 . The change in the local structure of La cation among these compounds was investigated by carrying out Photoluminescence study on 2 atom% Eu 3+ ‐doped samples. PL study of BaLaMgNbO 6 :Eu 3+ sample indicates Eu 3+ ions occupying the distorted 12‐coordinated A‐site, while in Ba 2 LaNbO 6 : Eu 3+ , Eu 3+ is present at highly symmetric octahedral B‐site. Upon excitation, the light emission of these compounds changes from reddish‐orange to red to purple in the order Ba 2 LaNbO 6 :Eu → BaLaCaNbO 6 :Eu → BaLaMgNbO 6 :Eu 3+ , due to change in Eu 3+ ‐ions site occupancy. Lifetime study also confirmed the presence of two different Eu 3+ components at two different lattice sites and their respective emission spectra were isolated by time resoled emission spectroscopy. Furthermore, this site selective lattice occupancy of Eu 3+ ions also gave various new insights about its radiative and nonradiative properties at different lattice sites. This works presents a complete structural understanding of BaLaMNbO 6 ‐based matrices and their versatile phosphor characteristics when doped with Eu 3+ ion.