Abnormal temperature dependent luminescence behavior of CaSrSiO4:Eu2+ phosphors synthesized via sol-gel strategy

A silicate based crystal doped with Eu2+ phosphors have been synthesized by sol-gel method using propylene glycol modified silane (PGMS). The structural and luminescence properties of the as-prepared samples were well characterized by using x-ray diffractometer (XRD) & photoluminescence spectroscopy. Thermal stability of the prepared phosphors was also measured and analyzed in detail. The results revealed a new fact that longer wavelength emission band position is relatively more sensitive to the sample temperature for higher dopant concentrations when compared to the other emission bands. Such observations were not found in the samples prepared by solid phase reaction method. The CaSrSiO4 phosphor doped with 3 mol % of Eu2+ showed unique optical properties that consist of a shift in emission spectrum towards shorter wavelength along with a decreased band width (FWHM). The emission color tunability with the increase in temperature and concentration of the CaSrSiO4 phosphor were also discussed by CIE chromaticity diagram.