Title

Eu2+ -Activated Ca8Zn (SiO4)4Cl2: An Intense Green Emitting Phosphor for Blue Light Emitting Diodes

Document Type

Article

Publication Date

2011

Publication Title

Journal of the Electrochemical Society

DOI

10.1149/1.3518763

Abstract

We report intense green luminescence upon blue light excitation in Eu2+ -activated Ca8Zn(SiO4)4Cl2 prepared by high temperature solid state reaction with nominal composition of (2−x)CaO-xZnO–SiO2–CaCl2(0⩽x⩽1.1) . It is observed that the material phase gradually converts from Ca3SiO4Cl2:Eu2+ to Ca8Zn(SiO4)4Cl2:Eu2+ followed by improved luminescent properties with increasing x . The two phosphors both emit with a maximum at 505nm . Significantly, Ca8Zn(SiO4)4Cl2:Eu2+ shows a more intense excitation band in the blue centered at 450nm . Upon 450nmexcitation, the integrated emission intensity of Ca8Zn (SiO4)4Cl2:Eu2+ is 1.3 times stronger Ca8Mg(SiO4)4Cl2:Eu2+ and nearly the same as Ca3Sc2Si3O12:Ce3+ phosphors. Attempts to understand the origins of the intense luminescence are presented on the basis of diffuse reflection spectra and fluorescence decays of Ca8Zn(SiO4)4Cl2:Eu2+ in comparison with related phosphors. The present results suggest that Ca8Zn(SiO4)4Cl2:Eu2+ could be a promising green emitting phosphor for excitation by blue light emitting diodes.

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