Thermostability and photostability of Sr{sub 3}SiO{sub 5}:Eu{sup 2+} phosphors for white LED applications

Journal Article · Fri May 15 04:00:00 EDT 2015 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/J.JSSC.2014.12.005· OSTI ID:22475578

Shao, Qiyue ^[1]; Lin, Huanyun; Dong, Yan ^[1]; Fu, Yibin; Liang, Chao; He, Jinhua ^[2]; Jiang, Jianqing ^[1]

---

1. School of Materials Science and Engineering, Southeast University, Nanjing 211189 (China)
2. Jiangsu Bree Optronics Co., Ltd., Nanjing 211103 (China)

Sr{sub 3}SiO{sub 5}:Eu{sup 2+} phosphors were synthesized by solid-state reactions, and their photoluminescence (PL) stability under the impact of heat or light was studied. The thermal degradation in air was observed for the Sr{sub 3}SiO{sub 5}:Eu{sup 2+} phosphor, furthermore, this drop in emission intensity could be accelerated by simultaneously illuminating the phosphor with a high-power blue LED during the heating process. This enhanced thermal degradation phenomenon in the blue light can be ascribed to the photo-assisted thermal oxidation of Eu{sup 2+} ions. A reversible decrease in emission intensity at room temperature was observed on illuminating the Sr{sub 3}SiO{sub 5}:Eu{sup 2+} phosphor alone by the blue light, which could be related to trapping centers in the phosphor. The existence of traps is also responsible for the anomalous increase of emission intensity with increasing temperature from 30 to 100 °C. Considering the influences of Ba{sup 2+} doping on temperature-dependent PL properties of the Sr{sub 3}SiO{sub 5}:Eu{sup 2+} phosphor, the thermal quenching origin may be ascribed to the thermally assisted photoionization process. - Graphical abstract: The photo-induced reversible decrease in emission intensity and the anomalous emission enhancement with increasing temperature are related to trapping centers in the phosphor. - Highlights: • The photo-assisted thermal degradation was observed for the Sr{sub 3}SiO{sub 5}:Eu{sup 2+} phosphor. • The phosphor showed a reversible intensity decrease under the blue light irradiation. • An anomalous emission enhancement with increasing temperature was found. • Ba{sup 2+} substitution could suppress the thermal quenching of Sr{sub 3}SiO{sub 5}:Eu{sup 2+}. • Mechanisms for photostability and thermostability were discussed.

• OSTI ID: 22475578
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Vol. 225; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
BARIUM IONS
EMISSION SPECTROSCOPY
EUROPIUM IONS
HEAT
HEATING
IRRADIATION
OXIDATION
PHOSPHORS
PHOTOIONIZATION
PHOTOLUMINESCENCE
QUENCHING
SOLIDS
STRONTIUM SILICATES
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0273-0400 K
THERMAL DEGRADATION
TRAPPING
TRAPS
VISIBLE RADIATION