Relationship between thermal quenching of Eu2+ luminescence and cation ordering in (Ba1-xSrx)2SiO4:Eu phosphors

The thermal quenching property of phosphors has been proven to have a strong impact on the application of them. In this paper, a series of (Ba1-xSrx)(2)SiO4:Eu2+ compounds have been synthesized via conventional high-temperature solid-state reaction. Based on the Rietveld fitting analysis of the X-ray diffraction data, the preferential occupancy behavior of Sr2+/Ba2+ ions is verified. We adopt the cation ordering to characterize this preferential occupancy and find that the degree of cation ordering reaches its maximum at x=0.5 and decreases as x deviates from 0.5. The photoluminescence measurements show that the intermediate composition (x=0.5) exhibits the best luminescence thermal stability with T-1/2 over 200 degrees C. The composition dependence of thermal quenching temperature is well similar to the composition dependence of the degree of cation ordering, indicating that the thermal quenching property of (Ba1-xSrx)(2)SiO4:Eu2+ is positively related to the cation ordering. This work provides a deeper understanding between thermal quenching properties and crystal structures of phosphors. (C) 2016 Elsevier B.V. All rights reserved.