Preparation of SrAl2O4: Eu2+, Dy3+ Powder by Combustion Method and Application in Anticounterfeiting

Abstract

Green emitting long afterglow phosphor SrAl2O4: Eu2+, Dy3+ was synthesized via the combustion method. The physical phase analysis was carried out by X-ray diffraction, the results show that the introduction of Eu2+ into the lattice of the matrix resulted in a broad green emission centered at 508 nm, which is ascribed to the characteristic 4f65d1 to 4f7 electronic dipole allowed transition of Eu2+ ions. The doping of Eu2+ and Dy3+ did not change the physical phase of the crystals. Dy3+, as a coactivator, does not emit light itself, but can generate holes to form a trap energy level, which acts as an electron trap center to capture some of the electrons generated by the excitation of Eu2+. After excitation has ceased, let them gradually to transfer to the ground state for long afterglow luminescence. Then, we investigate the optical characterizations of different samples excited by X-ray. We found that SrAl2O4: Eu2+, 0.5% Dy3+ has this higher luminous intensity and afterglow. Its fluorescence lifetime is about 720 ns, and its quantum yield can reach 15.18%. Through search engine marketing (SEM) and energy dispersive X-ray spectroscopy (EDX), it has been proved that the sample has been successfully synthesized and its component content has been confirmed. The Eg value calculated from the diffuse reflectance spectrum is 4.61eV. The prepared SrAl2O4: Eu2+, Dy3+ luminescent powder is combined with Polydimethylsiloxane substrate for anticounterfeiting application, which provides a novel idea and method for the development of the anticounterfeiting field.