Preparation and Photo luminescent Properties of Sr2Si5N8: Eu2+Red Phosphors for White Light-Emitting Diodes

Abstract

This paper study a simple, inexpensive synthetic route to Sr2Si5N8:Eu2+ based red nitride phosphors for white light-emitting diodes (WLEDs). The Eu2+ doped Sr2Si5N8 nitride phosphor were synthesized by carbothermal reduction and nitridation method using SrCO3, Si3N4 and Eu2O3 as raw materials, and carbon as main reduction agent. Sr2Si5N8:Eu2+ phosphors was obtained at 1600°C under N2 atmosphere. Sr2Si5N8:Eu2+ phosphors structure were investigated using X-ray diffraction (XRD); the phosphors excitation spectrum, emission spectrum and decay lifetime were obtained by fluorescence spectrophotometer. Excitation spectrum of Sr2Si5N8:Eu2+ phosphors showed a broad excitation bands peaking at 632 nm by both UV and blue light. There is an asymmetric wide emission peaks between 500 nm and 750 nm originated from the 4f65d1-4f7 transitions of Eu2+ ion. And the lifetime of Eu2+ in the Sr2Si5N8 host is 1919.81 ns. The CIE chromaticity coordinates of Sr2Si5N8:Eu2+ phosphors are (x=0.5549, y=0.4316).