Peculiar Optical Characteristics of Different Silicate Source and Synthesis Technique in Europium Doped Li2SrSiO4

Abstract

In this work, a silicate based phosphor doped with divalent and trivalent europium (Eu(2+/3+)) ions have been synthesized by two different synthesis processes, PGMS (propylene glycol modified silane) assisted sol-gel and solid state reaction (SSR) method. The structural, morphological and optical properties were studied in detail. The emission intensity of Li2SrSiO4:Eu3+ phosphors synthesized through the PGMS assisted sol-gel increased up to 10 times more than that prepared by SSR method. However, Li2SrSiO4:Eu2+ phosphor prepared by PGMS exhibited lower emission characteristics and decreased to one-third of that prepared by SSR. The Eu3+ doped Li2SrSiO4 synthesized by SSR method using different silicate (Si) sources revealed peculiar optical properties and this is the first kind of its report. The obtained results suggest that the optical properties of Eu(3+/2+) doped in silicate host can be regulated by the alteration of Si source besides sample preparation method. These results open a way to understand the mechanisms responsible for such optical properties and to develop new materials for white LEDs.