Structural changes and self-activated photoluminescence in reductively annealed Sr{sub 3}AlO{sub 4}F
- Department of Chemistry, Allen University Columbia, Columbia, SC 29204 (United States)
- Bragg Institute, Australian Science and Technology Organization, PMB 1, Menai, NSW 2234 (Australia)
White light emission of self-activated photoluminescence (PL) in Sr{sub 3}AlO{sub 4}F under 254 nm light is only observed after annealing in a reducing atmosphere of 5%H{sub 2}/95%Ar. High-resolution neutron powder diffraction reveals that the FSr{sub 6} octahedrons and AlO{sub 4} tetrahedrons in this anti-perovskite structure are closer packed in reduced than in air-annealed samples which show no PL. Careful analysis of temperature-dependent neutron powder diffraction data establishes smaller isotropic displacement parameters for Sr(1) and O in Sr{sub 3}AlO{sub 4}F annealed in a reducing atmosphere indicating that the denser packing of the polyhedral sub-units leads to a slightly deeper potential for the Sr(1) and O atoms. Both the air- and reductively-annealed samples have identical thermal expansion within the temperature range between 3 and 350 K. The Debye temperatures were calculated using the atomic displacement parameters and show no significant differences between the air and reductively annealed samples making the Debye temperature a bad proxy for self-activated PL. - Graphical abstract: Annealing Sr{sub 3}AlO{sub 4}F under reducing conditions results in an intense self-activated photoluminescence which is correlated with a denser packing of FSr{sub 6} and AlO{sub 4} polyhedra. - Highlights: • Sr{sub 3}AlO{sub 4}F made in air does not show self-activated photoluminescence. • Only when annealing Sr{sub 3}AlO{sub 4}F in a reducing gas is photoluminescence observed. • FSr{sub 6} and AlO{sub 4} polyhedra in reduced Sr{sub 3}AlO{sub 4}F structure are packed more efficient. • Smaller displacement parameters are found for under-bonded Sr(1) and O sites.
- OSTI ID:
- 22486714
- Journal Information:
- Journal of Solid State Chemistry, Vol. 228; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
Similar Records
Structure-composition-luminescence correlations in Sr{sub 2.5-3x/2}Ba{sub 0.5}Sm{sub x}Al{sub 1-y}In{sub y}O{sub 4}F (0.001{<=}x, y{<=}0.1) oxyfluorides
Structures and self-activating photoluminescent properties of Sr{sub 3-x}A{sub x}GaO{sub 4}F (A=Ba, Ca) materials