Energy transfer and the anti-thermal quenching behavior of Sr8MgCe(PO4)7:Tb3+ for temperature sensing

Novel color-adjustable phosphors Sr8MgCe(PO4)7:Tb3+ were synthesized by the solid-state reaction method. The X-ray diffraction was used to characterize the phase formation. The host shows blue emission under 310 nm excitation, ascribed to the 5d-4f transitions of Ce3+, while Sr8MgCe(PO4)7:xTb3+ phosphors exhibit the emission band of Ce3+ as well as the characteristic lines of Tb3+ under 310 nm excitation. The color variation was observed as the concentration of Tb3+ changes. Moreover, the host sensitizes the emission of Tb3+ through the energy transfer process, and the mechanism is the dipole–dipole interaction. In addition, the emission of the host declines with the increase of the temperature while that of Tb3+ increases. This anti-thermal quenching behavior was interpreted by the configurational coordinate diagram. In addition, the temperature sensing behavior based on the emission peaks of the host and Tb was studied in the range 298–523 K, and the largest sensitivity is 0.379% K−1. The results indicate that Sr8MgCe(PO4)7:Tb3+ is an attractive color-tunable phosphor for solid state lighting and temperature sensing.