Hydrothermal synthesis and afterglow luminescence properties of hollow SnO2:Sm3+,Zr4+ spheres for potential application in drug delivery

A novel afterglow labeling material SnO2:Sm3+,Zr4+ with hollow sphere shape and intense afterglow luminescence is prepared by hydrothermal method at 180 °C for the first time. The morphology and the sphere growth process of this material are investigated by scanning electron microscopy in detail. The afterglow measurement shows that this hydrothermal obtained material exhibits obvious red afterglow luminescence (550–700 nm) of Sm3+ which can last for 542 s (0.32 mcd/m2). The depth of traps in this hydrothermal obtained material is calculated to be as shallow as 0.58 eV. The results demonstrate that although it is necessary to further improve the afterglow performance of the hydrothermal derived hollow SnO2:Sm3+,Zr4+ spheres, it still can be regarded as a potential afterglow labeling medium for drug delivery.