The influence of processing parameters on structural and luminescent characteristics of an Eu2+-doped Sr-Si-O-N system

Abstract

Eu2+-doped Sr-Si-O-N material phosphors were synthesized using a high temperature solid state reaction. High solubility of nitrogen in an oxynitride system is known as a labored process when it occurs under high nitrogen pressure. The factors influencing structural and luminescent characteristics of Eu2+-doped SrSi2O2N2 system have been investigated in detail. In a SrSi2O2N2 system, the peak emission spectra change with processing parameters such as gas flow rate, which results in a different O/N ratio. The optical and structural properties are also dependent upon the reaction temperature and reaction period. For instance, the SrSi2O2N2:Eu2+ system is converted into a Sr2Si5N8-alpha O alpha system when exposed to a longer reaction at higher temperature. XPS and FTIR analyses confirm the variation in structural changes which affect the emission wavelength of the phosphor. This metamorphosis seems to be related to the unstable longevity of oxynitride material phosphors.