Emission-tunable Sr1-n-2x-yBanMg2(PO4)2:xCe3+, yEu2+, xNa+ phosphors for optical temperature sensing

To develop novel phosphors for optical temperature sensors, a series of Sr1-n-2x-yBanMg2(PO4)(2):xEu(2+), yCe(3+), yNa(+) (SBnMP:xEu(2+), yCe(3+), 0.0015 <= x <= 0.0075, 0 <= y <= 0.015, 0 <= n <= 0.5) phosphors were designed, and their photoluminescence properties were investigated. For Eu2+ single-doped SMP phosphors, broad emission bands around 411 nm are obtained upon 365 nm excitation. However, when the Ba2+ ions are introduced into the SMP: Eu2+, a new Eu2+ emission band at 388 nm appears and the dominant emission peak has shifted gradually from 411 to 388 nm with the Ba2+ concentration changing from 0 to 40 mol%. For Ce3+ single-doped SMP and SB0.35MP phosphors, most of the emission bands are located in the near-UV region. By codoping Eu2+-Ce3+ into the SMP and SB0.35MP hosts, an efficient energy transfer (ET) from Ce3+ to Eu2+ occurs, and the ET efficiency has been calculated by using the decay lifetimes of Ce3+. The investigation of the thermal stability luminescence reveals that the emission intensities of Ce3+ and Eu2+ single-doped samples exhibit an opposite changing tend with increasing temperature. Thus, the intensity ratio of the Ce3+ to Eu2+ emissions will demonstrate obvious change regulation with temperature when the Ce3+-Eu2+ ions are codoped into the SBnMP, which could be used for the temperature sensor. Moreover, it has been found that the present phosphors could show high sensitivity. (C) 2017 Published by Elsevier B.V.