A thermally stable Ce3+ activated green phosphor for illuminating and temperature sensing application

The discovery of efficient green phosphor is of great interest in wide range of applications in lighting, display, scintillator, and temperature sensing. Herein, an innovated Ce 3+ -substituted green-emitting gallate phosphor is presented. The green emission in CaYGaO 4 :Ce 3+ originates from Ce 3+ occupying at octahedrally coordinated Y 3+ site rather than Ca 2+ site. This preferential substitution is identified by DFT-based formation energy calculations and supported by Rietveld refinement and photoluminescence spectra. The Ce 3+ ion experiences a strong crystal field splitting on the 5d states, and ultimately shifts the emission into green spectra region with dual emission band at 508 and 588 nm (λ ex = 460 nm). The phosphor exhibits excellent thermal quenching property, as its integrated photoluminescence intensity at 150 °C and 250 °C can retain 72.33 % and 54.11 % of that at room temperature, respectively, resulting from the reduced nonradiative losses. A prototype WLED fabricated by coating the green emitting CaYGaO 4 :Ce 3+ phosphor and red emitting CaAlSiN 3 :Eu 2+ phosphor onto a blue LED chip yields a warm light with uniform light distribution. And also, by utilizing the fluorescent intensity ratio of the two emission bands as a temperate index, the promising application of the phosphor for remote temperature sensing is also demonstrated.