Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province and State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, 730000, China.
School of Civil Engineering and Architecture, Zhongyuan University of Technology, Zhengzhou 450007, China.
Dalton Trans. 2021 Mar 9;50(9):3193-3200. doi: 10.1039/d0dt04231e.
Luminescent materials play an important role in anticounterfeiting applications due to their superior properties of visual convenience and high concealment. However, traditional luminescent materials usually exhibit monochromatic emission and are easily counterfeited. Therefore, in this work, we report a multicolor long persistent luminescence (PersL) material, NaCa2GeO4F:Tb3+ (abbreviated as NCGOF:Tb3+), where the color of PersL can be tuned from blue to cyan and bright green by changing the concentration of Tb3+, and the afterglow (concentration) can last for 5.62 h (0.1%), 8.52 h (0.4%) and 7.14 h (0.8%) at the corresponding concentrations of Tb3+, respectively. Investigation revealed that the multicolor PersL is essentially associated with the opportune traps and cross-relaxation effect of Tb3+ in NCGOF. Based on the unique features of PersL, anticounterfeiting devices have been fabricated, and the results indicate that their multicolor features can be easily detected using a portable ultraviolet lamp, and that they are impossible to counterfeit using any substitute so far, meaning that they provide a high level of security for use in practical applications.
发光材料因其视觉方便和高度隐蔽的优异特性，在防伪应用中起着重要作用。然而，传统的发光材料通常表现出单色谱发射，并且容易被伪造。因此，在这项工作中，我们报告了一种多色长余辉（PersL）材料，NaCa2GeO4F:Tb3+（简称 NCGOF:Tb3+），其中 PersL 的颜色可以通过改变 Tb3+的浓度从蓝色调谐到青色和亮绿色，并且余辉（浓度）分别在相应的 Tb3+浓度下可以持续 5.62 h（0.1%）、8.52 h（0.4%）和 7.14 h（0.8%）。研究表明，多色 PersL 本质上与 NCGOF 中 Tb3+的适时陷阱和交叉弛豫效应有关。基于 PersL 的独特特性，已经制造了防伪设备，结果表明，它们的多色特征可以使用便携式紫外线灯轻松检测到，并且迄今为止，使用任何替代品都不可能伪造它们，这意味着它们为实际应用中的使用提供了高度的安全性。
