Xuan Liu,Xiaojia Su,Zhuohang Ren,Lingqiu Yang,Xinyue Zhang,Mingye Ding
Currently, developing advanced optoelectronic materials is of great importance to solving serious problem of fake and shoddy products. Lanthanide-doped nanomaterials are particularly suitable for addressing this issue, but limited by the realization of multiple upconverison (UC) emissions upon a single-wavelength laser excitation. Herein, it is proven that the co-dopant of blue/near-infrared (NIR)-emitting activators (Tm 3+ ) and green/red-emitting centers (Er 3+ ) in a particular designed core–shell nanoarchitecture allows the achievement of multiple luminescence over wide spectral region for optical security. In our study, cubic-phased NaYbF 4 :Tm/Er@CaF 2 nanocrystals have been successfully synthesized through a layer-by-layer coprecipitation strategy, which presents visible multicolor UC luminescence and invisible NIR UC emission upon 980 nm laser excitation by just regulating the laser power and temperature. Significantly, the unique luminescent characteristics enables the designed UC nanoparticles a promising candidate for advanced anti-counterfeiting. This works offers a reference to develop advanced optoelectronic materials for practical application in optical security.
Linglu Kuang,Feng Zhang,Jian Zhang,Xiaodie Zhu,Xu Tian,Jianxiong Shao,Yichun Liu,Xuhui Xu,Zhichao Liu
Optical materials are widely used in the information coding, display, and anti-counterfeiting fields due to their tunable color. However, the regulation of the color change in a material is mainly achieved by co-doping with different ions to achieve multimode luminescence, which greatly increases the difficulty of material synthesis. Herein, CaF2:Eu with different doping amounts of Eu ions as an anti-counterfeiting material is synthesized in one step by a simple high-temperature solid-state method. The concentration of Eu can adjust the reduction ratio of Eu ions and give the material multicolor emission. Moreover, X-ray-induced ion reduction achieves the multicolor emission of Eu2+ and Eu3+ ions in a single matrix of CaF2:Eu. This achieves radio-photo luminescence (RPL). In addition, the mechano-luminescence (ML) of CaF2: 0.5%Eu has also been confirmed. These findings provide unique insights into the design of highly integrated advanced anti-counterfeiting technologies using multi-stimuli-responsive luminescent materials.
危险品化学品经营许可证（带存储）