Luminescent properties of Eu3+-doped NaLaCaWO6 red phosphors and temperature sensing derived from the excited state of charge transfer band

In this study, a series of NaLaCaWO 6 : Eu 3+ phosphors were synthesized by traditional high-temperature solid-phase method. The doping concentration of Eu 3+ was explored when the phosphors had the best luminescence performance, and the quenching concentration of Eu 3+ could reach 30%. The mechanism of concentration quenching is due to electric dipole-electric dipole interaction . The CIE coordinates of the phosphor are (0.66, 0.34), which are close to the standard red region of National Television Standard Committee (NTSC). Therefore, the samples could be potentially used as red phosphors of white light emitting diodes . The optical thermometry properties of NaLaCaWO 6 :30%Eu 3+ phosphors in 298–523 K were studied through temperature-dependent excitation spectra. The results demonstrate negative thermal quenching at the edge of the charge transfer band (CTB) with a red shift of the center of this band as temperature arises. Derived from the excited state of CTB , an optical temperature sensing strategy is proposed, and the relative sensitivity achieves 2.23%/K −1 .