Luminescence and Energy Transfer of Dual-Emitting Solid Solution Phosphors (Ca,Sr)10Li(PO4)7:Ce3+,Mn2+ for Ratiometric Temperature Sensing

A series of novel dual-emitting solid solution phosphors, (Ca,Sr) 10 Li(PO 4 ) 7:Ce 3+, Mn 2+ (CSLP:Ce 3+,Mn 2+ ), were synthesized by high-temperature solid-state method. CSLP:Ce 3+,Mn 2+ exhibits both Ce 3+ violet emission and Mn 2+ red emission under UV excitation. It is found that Sr 2+ partial substitution of Ca 2+ could result in enhancement of Mn 2+ emission intensity and blue-shift of Mn 2+ emission wavelength, which is due to site symmetry reduction and polyhedron expansion, respectively. The Ce 3+ –Mn 2+ energy transfer (ET) is efficient (∼90%), and the ET mechanism is dipole–dipole interaction. The application potential of CSLP:Ce 3+,Mn 2+ in optical thermometry was studied by exploiting the temperature sensitivity of the fluorescent intensity ratio (violet/red). It is found that the intensity ratio of the Ce 3+ and Mn 2+ emission peak linearly related to the temperature from 293 to 473 K with sensitivity of 0.40% K –1 . These results reveal that CSLP:Ce 3+,Mn 2+ may be a potential candidate for a luminescent ratiometric thermometer with wide temperature range.