Dual-mode luminescent multilayer core-shell UCNPs@SiO2@TEuTbB nanospheres for high-level anti-counterfeiting and recognition of latent fingerprints

Abstract

Currently, illegal counterfeiting activities are increasing with the continuous developments of society and the fabrication of high security anti-counterfeiting techniques is becoming essential. The lanthanide-doped nanomaterials have great potential in anti-counterfeiting for their high luminescence intensity, narrow half-peak width and high stability. Herein, the dual-mode luminescent UCNPs@SiO2@TEuTbB nanomaterials have been successfully fabricated for anti-counterfeiting. Morphology, structure and luminesce properties of the synthetic samples have been investigated via TEM, XRD, FT-IR, XPS and fluorescence spectroscopy. The results present that the size of the synthetic materials is about 100 nm. The luminesce properties clearly show that the UCNPs@SiO2@TEuTbB nanomaterials can emit strong UC red color under the NIR light. Meanwhile, these materials can emit several DC luminescence colors by adjusting Eu3+ ions concentration under UV lamp. Furthermore, the lanthanide-doped nanomaterials are widely used in recognition of LFPs providing valuable evidence in forensic filed. As a result, the images of LFPs developed by the as prepared materials on various surfaces under UV lamp can be well visualized. The three levels details of fingerprints are clearly visible with high sensitivity, selectivity and contrast. Thus, these results confirm that the synthetized UCNPs@SiO2@TEuTbB nanospheres can provide a foundation for high-level anti-counterfeiting and the detection of fingerprints.