In the information age, it is important to protect the security and integrity of the information. As a result, the fluorescent ink as an antifake technology and the fingermark as an information carrier have aroused great interest. In this work, highly water-soluble lanthanide (Ln3+ )-doped tetragonal phase (t-) LaVO4 nanoparticles (NPs) are successfully obtained via a simple, fast, and green microwave-assisted hydrothermal method. The average size of t-LaVO4 NPs is about 43 nm. The aqueous solutions of Ln3+ -doped t-LaVO4 exhibit excellent fluorescence properties under ultraviolet light (UV) excitation (t-LaVO4 :10%Eu is bright red and t-LaVO4 :0.5%Dy is close to white). Some superb antifake fluorescent patterns are printed using Ln3+ -doped t-LaVO4 aqueous solution as ink, which indicates the as-prepared Ln3+ -doped t-LaVO4 NPs as fluorescent ink can meet the various antifake requirements. Notably, the designed convenient antifake fluorescent codes with improved security could be directly scanned and decoded by a smart phone. What's more, the as-prepared NPs can be used for the development of latent fingermark on various substrates and the second-level detail information can be clearly obtained from the magnification of a fingermark. These results indicate that the as-prepared Ln3+ -doped t-LaVO4 fluorescent NPs have great potential in security application.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: C.C. and Y.Y. contributed equally to this work. This work was supported by the Foundation of the Natural Science Foundation of China (Nos. 21621001 and 21371069), the National Key Research and Development Program of China (No. 2016YFB0701100), the 111 project (No. B17020), the S&T Development Program of Jilin Province of China (No. 20160101325JC). The authors also gratefully acknowledge the financial support from the Natural Science Foundation of China through Research Fund for International Young Scientists scheme (No. 21550110190).