Facile preparation of silicate phosphor activated with low concentration of Eu2+ ions for highly efficient warm white light production

Abstract

In this work, a new yellow-emitting Ca2SiO4 based Eu2+ ion doped phosphor has been successfully developed using a propylene glycol modified silane (PGMS) as silicate source. The phosphor material obtained is subjected to detailed structural and luminescent studies. The results obtained show that the XRD patterns of Eu2+ doped Ca2SiO4 phosphors are in good agreement with the Ca2SiO4 (ICSD No: 79533) whose structure is monoclinic. The output of the luminescence studies clearly portrays a broad yellow emission between 450 and 800nm with a peak at ~630nm under the broad excitation range. This confirms its efficient emission towards the development of a warm white light using blue and near ultraviolet (NUV) LEDs. Meanwhile, the same phosphor synthesized using conventional silicate source via solid state reaction technique showed no shift in the emission wavelength. But, the PGMS supported synthesis of Ca2SiO4:Eu2+ phosphor emitted in a broad spectral range with an efficient red shift in the peaking wavelength. These results are showing off the possibilities to produce warm white light using single phosphor with blue or NUV LEDs. Hence, it is capable to replace the conventional YAG:Ce3+ phosphors which give white light with low color-rendering index due to the lack of emission in the red spectral region.