An insight into Judd-Ofelt analysis and non-contact optical thermometry of LiCa2Mg2V3O1: Dy3+ phosphors for multifunctional applications

A series of Dy3+ doped LiCa2Mg2V3O12 phosphors have been synthesized by solid state method. The phase composition of the phosphor has been analyzed by X-ray powder diffraction and confirms a cubic phase with Ia-3d space group. The scanning electron microscope images of LiCa2Mg2V3O12:xDy3+ phosphor reveals the surface morphology and is further investigated by its energy dispersive X-ray spectrum. The elemental mapping analysis displays the uniform composition of the elements present in the phosphor. The band gap energy of the phosphors has been determined from the diffuse reflectance spectra. The Judd-Ofelt intensity parameters are determined from the absorption spectra and follows the trend Ω2 > Ω6 > Ω4. The photoluminescence spectra of phosphors excited at 338 nm have intense emission at 494 and 576 nm corresponding to 4F9/2 →6H15/2 and 4F9/2 →6H13/2 transition and is ascribed to the magnetic and electric dipole allowed transition respectively. The radiative parameters for the optimum dopant concentration x = 0.08 has been calculated. Temperature dependent PL spectra of phosphor displays the diverse thermal response of VO43− group and Dy3+ ion and this can be utilized for the development of thermosensor based on fluorescence intensity ratio (FIR). The phosphor have maximum absloute and relative sensitivity values of 0.0063 K−1 and 0.41% K−1 in the temperature range of 80–400 K. The optical properties of the phosphor suggest that it find applications in the fields of solid-state lighting, temperature sensing, optoelectronic devices and W-LEDs.