Luminescence behavior of europium activated strontium aluminate phosphors by solid state reaction method

• Published in: Journal of materials science. Materials in electronics Vol. 27; no. 4; pp. 3443 - 3455
• Main Authors: Sahu, Ishwar Prasad, Bisen, D. P., Brahme, N., Tamrakar, Raunak Kumar
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-04-2016; Springer Nature B.V
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Emission; Excitation; Impact velocity; Materials Science; Optical and Electronic Materials; Phosphors; Pistons; Reaction kinetics; Solid state; Glow Curve; Glow Peak; Impact Velocity; SrAl2O4; Trap Depth
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-015-4177-7

The SrAl
2
O
4
:Eu
2+
and SrAl
2
O
4
:Eu
3+
phosphors were prepared by the traditional high temperature solid state reaction method. The crystal structures of the prepared phosphors were consistent with standard monoclinic phase with a space group P2
1
. The different TL kinetics parameters [activation energy (E), frequency factor (s) and order of the kinetics (b)] were evaluated and compared by using the peak shape method. Under the ultra-violet excitation (344 nm), the SrAl
2
O
4
:Eu
2+
phosphor would emit green light, belonging to the broad emission band ascribed to the 4f
6
5d
1
 → 4f
7
transition. The emission spectrum of SrAl
2
O
4
:Eu
3+
phosphor was consisted of two emission peaks at 590 and 615 nm, which were attributed to
5
D
0
 → 
7
F
1
and
5
D
0
 → 
7
F
2
of Eu
3+
ions. The strongest excitation band at 396 nm can be assigned to
7
F
0
 → 
5
L
6
transition of Eu
3+
ions due to the typical f–f transitions of 4f
6
configuration. Commission International de I’Eclairage color coordinates of prepared SrAl
2
O
4
:Eu
2+
and SrAl
2
O
4
:Eu
3+
phosphors were suitable as green and orange-red light respectively. The mechanoluminescence (ML) intensity of prepared SrAl
2
O
4
:Eu
2+
and SrAl
2
O
4
:Eu
3+
phosphors increase linearly with increasing impact velocity of the moving piston (load). Thus the present investigation indicates that the piezoelectricity was responsible to produce ML in sintered phosphors. Decay rates for different impact velocities were also calculated using curve-fitting techniques. The time of the peak ML and the rate of decay did not change significantly with respect to increasing impact velocity of the moving piston and peak ML intensity varied linearly.