Reddish orange long afterglow phosphor Ca2SnO4:Sm3+prepared by sol–gel method

A reddish orange light emissive long afterglow phosphor, Ca2SnO4:Sm3+ was prepared by sol–gel method at lower temperature. The synthesized phosphors were characterized by X-ray diffraction, scanning electron micrograph images, photoluminescence spectra, afterglow decay curves and thermoluminescence spectra. Three emission peaks locate at 565 nm, 609 nm and 655 nm corresponding to CIE chromaticity coordinates of x = 0.53 and y = 0.47, which indicates the reddish orange light emitting. The fluorescent intensity and the afterglow characteristic depends on the concentration of Sm3+ and the optimized concentration is 1.5 mol%. The afterglow decay curves are well fitted with triple-exponential decay models. The thermoluminescence glow curves show that the Sm3+ induces suitable trap depth and result in the long afterglow phenomenon, and the corresponding increase or decrease in afterglow is associated with trap concentration, nearly no change in trap depth. The 1.5 mol% Sm3+-doped Ca2SnO4 sample has the biggest trap concentration and exhibit the best afterglow characteristic, its’ afterglow time is about 1 h. The phosphorescence mechanism of this long afterglow phosphor was discussed.

► A promising reddish orange emissive long afterglow phosphor Ca2SnO4:Sm3+ prepared by sol−gel method was firstly reported.
► The optics properties of Ca2SnO4:Sm3+ were discussed.
► Very useful tool, thermoluminscent technique was chosen to investigate the traps in the material. The results of thermoluminscent spectra indicating that the depth and number of traps are critical factors in determining their performance.
► Furthermore, the phosphorescence mechanism was discussed successfully.
► This work provides a potential approach to develop reddish orange light emitting long afterglow phosphor.