Photoluminescence and ratiometric thermo-response of Eu2+ and Eu3+ in BaAl2B2O7:Eu2+,Eu3+ phosphor materials

A novel Eu2+-Eu3+ co-activated ratiometric thermo-sensitive phosphor was developed and synthesized by solid-state reaction. The valence state of Eu, photoluminescence and thermo-sensitive performance of the phosphor prepared either in ambient air or carbothermally were investigated and discussed. The phosphor shows high sensitivity (Sa = 0.0173 K–1, Sr = 0.461%/K) and superior signal discriminability (Δν = ∼10380 cm−1). The thermo-sensitive performance is subject to the dual effects of different thermo-responses by Eu2+ versus Eu3+ combined with energy transfer from Eu2+ to Eu3+, so that the sensitivity of the phosphor in the temperature range presents a non-monotonic trend. The development of the BaAl2B2O7:Eu2+,Eu3+ phosphor is not only expected to be relevant for application in the field of temperature sensing, but also of reference significance for improving the sensitivity by means of energy transfer between co-activator ions over a wider temperature range of Eu2+-Eu3+ co-activated ratiometric thermo-sensitive phosphors. 1.