Luminescent properties and temperature sensing of Mn4+/Tb3+ doped CaAl2Si2O8 phosphors.

Mn4+/Tb3+ doped CaAl 2 Si 2 O 8 (CASO) phosphors were synthesized using high temperature solid-state method. Crystal structure and lattice parameters were acquired through X-ray diffraction technique and Rietveld refinement. Energy band and density of states of CASO host were given by density functional theory calculations. By calculating the bond lengths and total energies of Mn4+ doped CASO, the results show that Mn4+ occupies the Ca2+ site with six coordinating oxygen atoms in the phosphor. The CASO:Mn4+,Tb3+ phosphors exhibit two major emission bands originating from the red emitting of Mn4+ (2E g → 4A 2g) and the green emitting of Tb3+ (5D 4 → 7F 5). Due to the emitting intensity of Mn4+ and Tb3+ varies differently with temperature, the temperature sensing study was carried out adopting the fluorescence intensity ratio of Tb to Mn. The relative sensitivity of CASO:1.5%Mn4+,6%Tb3+ achieves a peak value of 3.38 % K−1 at 423 K. The repeatability was tested and the result showed that the sample exhibits excellent repeatability. The luminescence color of the employed phosphors transitions from orange to green as the temperature increases. These findings uncover potential applications of CASO:Mn4+,Tb3+ phosphors in temperature sensing and multicolor-tunable emitting. [ABSTRACT FROM AUTHOR]