Synthesis and characterization of nanocrystalline SrAl2O4:Eu, Dy long afterglow phosphors by sol-gel method

Eu2+, Dy3+co-doped nanocrystalline strontium aluminate phosphor powders with brightness and long afterglow were synthesized by the sol-gel method at 1200°C for 2 h. The samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results of XRD show that the single crystalline phase is α-SrAl2O4. According to the observation of SEM, the particles of the samples are needle-like. Compared with the samples synthesized by solid state reaction, the grain size of the sol-gel method is to nanometer grade. A clear blue shift occurs in the excitation and emission spectra. The blue shift in nanocrystalline SrAl2O4:Eu, Dy phosphor can be attributed to the quantum-size-effect of the luminescent particles.