The temperature-sensitive luminescence of (Y,Gd)VO4:Bi3+,Eu3+ and its application for stealth anti-counterfeiting

Anti-counterfeiting technologies are desired to protect products far away from the violation of dummy, fake and shoddy goods. The phosphor of (Y,Gd)VO4:Bi3+,Eu3+ was synthesized for the application of this purpose. Its photoluminescence was investigated by exciting with different wavelengths at variant temperatures. Wide emission color ranged from green through yellow to orange was tuned up by tailor-ing Bi3+ and Eu3+ concentrations. The temperature dependent luminescence and wavelength selective excitation of (Y,Gd)VO4:Bi3+,Eu3+ were observed, which provide different encryptions in anti-counterfeiting. To verify the feasibility in application, two anti-counterfeiting patterns were fabricated practically and excellent performance was obtained. Moreover, the physical mechanisms for the different phenomena of luminescence were elucidated from excitation spectra combining with the configuration coordinate model. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)