多色长余辉材料的发光性质及动态防伪应用

发光防伪具有可视性强、设计简便的特点, 是众多防伪技术中常用的方法。传统防伪材料存在发光颜色单一、防伪图案和颜色静态的缺点, 易于模仿, 亟需开发可实现动态、可靠防伪性能的发光材料。本工作采用水热法制备了铬掺杂镓锗酸锌多色长余辉材料, 并对其余辉性能和动态防伪应用进行研究。实验结果表明: 通过改变镓锗比, 可以调节蓝绿光和红光区的发射强度, 实现发光颜色的可调。该系列样品在波长为254和365 nm的紫外光激发下分别呈现白色和红色, 发光颜色具有多模态发光特征。此外该系列样品具有多色的余辉发光, 不同颜色的衰减速率不同, 可以实现余辉颜色随时间发生动态变化的效果。据此设计成的防伪图案, 发光颜色在时间维度上具有动态变化特性, 可显著提高防伪安全性, 表明所制备的铬掺杂镓锗酸锌多色长余辉材料在动态防伪领域有重要的应用前景。

Luminescence Property of the Multicolor Persistent Luminescence Materials for Dynamic Anti-counterfeiting Applications

Luminescent anti-counterfeiting has characteristics of visibility and convenience, which is a popular method in many anti-counterfeiting technologies. However, this anti-counterfeiting luminescent materials have the shortcomings of single emission color and static anti-counterfeiting pattern, leading to easy imitablity. It is urgent to develop new luminescent materials that can achieve dynamic and more reliable anti-counterfeiting performance. In this research, the multicolor persistent luminescence material, chromium doped zinc gallogermanate, was prepared by hydrothermal method. Its persistent luminescence property and dynamic anti-counterfeiting application potential were investigated. Experimental results show that the emission intensity in blue-green and red light regions can be adjusted by changing the raw materials ratio of gallium to germanium. Under the excitation of 254 and 365 nm UV light, a series of samples are observed to be white and red, respectively, indicating multi-mode luminescence characteristics. Furthermore, the decay rate of blue, green and red components in white afterglow is different, so the afterglow color can change dynamically over time. Anti-counterfeiting patterns, designed based on this multicolor afterglow features, improves the security through dynamic change of afterglow color in the time dimension, demonstrating the potential application in dynamic anti-counterfeiting.