An abnormal yellow emission and temperature-sensitive properties for perovskite-type Ca2MgWO6 phosphor via cation substitution and energy transfer

Abstract A series of Ca 2 MgWO 6 :Bi 3+ , Eu 3+ phosphors were prepared via a high temperature solid-state reaction method. The crystal structure of Ca 2 MgWO 6 :Bi 3+ , Eu 3+ phosphors adopt the double perovskite structure. Different from previous study, a yellow-emitting was observed in the Ca 2 MgWO 6 matrix. Roman spectrum indicated that the yellow emission is a result of the existence of oxygen vacancies during the preparation process. By co-doping Bi 3+ into Ca 2 MgWO 6 matrix, the yellow emission was enhanced due to the more defect concentration and the 3 P 1 - 1 S 0 transition of Bi 3+ . Two strategies containing cation substitution and energy transfer in single Ca 2 MgWO 6 compound were used to tune photoluminescence properties. Bi 3+ and Eu 3+ as substitution ions were co-doped into Ca 2 MgWO 6 matrix and the energy transfer from Bi 3+ to Eu 3+ caused the tunable emission color from yellow to deep red. The energy transfer mechanism from Bi 3+ to Eu 3+ ions has been defined to be a quadrupole-quadrupole interaction in our work. Notably, the Bi 3+ and Eu 3+ in this system showed excellent temperature sensing properties owing to different luminescent thermal quenching behaviors of Bi 3+ and Eu 3+ in the range of 298–523 K. In addition, the maximum values for absolute ( S a ) and relative ( S r ) sensitivities were calculated to be 0.961 K -1 (523 K) and 8.52% K −1 (323 K), respectively, which validates the possibility of optical thermometric applications of Ca 2 MgWO 6 :Bi 3+ , Eu 3+ phosphors.