Spectroscopic analysis of alkaline-earth metal (Mg, Ca, Sr and Ba) co-doped GdO:Eu phosphors synthesized via co-precipitation route.

This paper reports the effect of alkaline earth metals (AEM = Mg, Ca, Sr, Ba) co-doping on the structural, morphological and luminescent properties of GdO:Eu phosphors. The concentration of the Eu ions was fixed 4 mol% to avoid the chances of the concentration quenching. AEM co-doped GdO:Eu XRD profile confirmed the synthesis of cubic-phase of all the co-doped samples. FESEM micrographs exhibited the rod like morphology of the synthesized phosphors. All the samples were irradiated under UV excitation and exhibited intense, sharp and narrow emission spectra corresponding to the characteristic transitions (D → F) transitions of Eu ions. The photometric parameters such as CIE coordinates, CCT and color purity are calculated. In order to probe the further luminescent properties and influence of the of alkaline earth metals on the local environment of the Eu ions in the host lattice, spectral parameters are calculated from Judd Ofelt theory from emission spectra. The obtained results suggest that AEM can be effectively utilized to enhance the luminescence intensity even after concentration quenching. The as-synthesized phosphors can be used in various solid state lighting devices and bio-sensors.