Open AccessEffects of Er3+ concentration on the structure and optical properties of the MgAl2O4/MgO/Sr3Al2O6/SrAl2O4 mixed phases prepared by the citrate sol gel method
Author(s) -
C. Dlamini,
M.R. Mhlongo,
L.F. Koao,
T.E. Motaung,
T.T. Hlatshwayo,
Y. Dwivedi,
S.V. Motloung
Publication year - 2020
Publication title -
materials research express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.383
H-Index - 35
ISSN - 2053-1591
DOI - 10.1088/2053-1591/abbd04
Subject(s) - monoclinic crystal system , analytical chemistry (journal) , transmission electron microscopy , scanning electron microscope , materials science , luminescence , doping , absorption (acoustics) , crystallography , ion , powder diffraction , mineralogy , nuclear chemistry , crystal structure , chemistry , nanotechnology , optoelectronics , organic chemistry , chromatography , composite material
The mixed phases of the un-doped MgAl 2 O 4 /MgO/Sr 3 Al 2 O 6 /SrAl 2 O 4 (MMSS), MgAl 2 O 4 /MgO (MM) Sr 3 Al 2 O 6 /SrAl 2 O 4 (SS), and the doped MMSS:x% Er 3+ (0 ≤ x ≤ 1.8) nanopowders were synthesized using the citrate sol-gel method. The effect of Er 3+ concentration on the structure, morphology and optical properties were investigated. X-ray powder diffraction (XRD) analysis indicated the cubical MgAl 2 O 4 , MgO and Sr 3 Al 2 O 6 ; and monoclinic SrAl 2 O 4 phases. The scanning electron microscopic images revealed the transformation of irregular particles to rod-like structure with an increase in Er 3+ concentration. Transmission electron microscope indicated the nanosized particles depends on Er 3+ concentration. Severals distinct absorption bands located at 444, 546, 653 and 704 nm under UV excitation (285 nm) corresponding to the defects states of the MgAl 2 O 4 , MgO, SrAl 2 O 4 , and Sr 3 Al 2 O 6 phases were observed. There were traces of emission peaks at 546 and 653 nm attributed to the 4 S 3/2 → 4 I 15/2 and 4 F 9/2 → 4 I 15/2 transitions of Er 3+ ion. An exponential decrease in luminescence was observed with an increase in Er 3+ concentration.