Tunable afterglow color in Eu2+ and Dy3+ co-activated alkaline earth feldspar solid solutions phosphors

The Eu2+ and Dy3+ co-activated Ca–Sr feldspar solid solution compounds, (Ca0.98−xSrx)Al2Si2O8:Eu0.01,Dy0.01 (image), have been prepared by solid-state reaction in weak reductive atmosphere. The fluorescence spectra showed that the emission peaks of these phosphors shifts to shorter wavelength with an increase of Sr2+ solid solution quantity and correspondingly the afterglow color changes from blue to purple. All the changes can be attributed to the various crystal fields around Eu2+ ions. The afterglow with special short wavelength in near ultraviolet region can be obtained by adjusting the host chemical composition.