Department of Physics and Engineering, ITMO University, 49 Kronverkskiy av., St. Petersburg, 197101, Russia.
Alferov University, 8 Khlopina st., St. Petersburg, 194021, Russia.
Adv Mater. 2021 Apr;33(16):e2005886. doi: 10.1002/adma.202005886. Epub 2021 Mar 11.
The never-ending struggle against counterfeit demands the constant development of security labels and their fabrication methods. This study demonstrates a novel type of security label based on downconversion photoluminescence from erbium-doped silicon. For fabrication of these labels, a femtosecond laser is applied to selectively irradiate a double-layered Er/Si thin film, which is accomplished by Er incorporation into a silicon matrix and silicon-layer crystallization. The study of laser-induced heating demonstrates that it creates optically active erbium centers in silicon, providing stable and enhanced photoluminescence at 1530 nm. Such a technique is utilized to create two types of anti-counterfeiting labels. The first type is realized by the single-step direct laser writing of luminescent areas and detected by optical microscopy as holes in the film forming the desired image. The second type, with a higher degree of security, is realized by adding other fabrication steps, including the chemical etching of the Er layer and laser writing of additional non-luminescent holes over an initially recorded image. During laser excitation at 525 nm of luminescent holes of the labels, a photoluminescent picture repeating desired data can be seen. The proposed labels are easily scalable and perspective for labeling of goods, securities, and luxury items.
与假冒伪劣作斗争永无止境，这就需要不断开发安全标签及其制造方法。本研究展示了一种基于掺铒硅下转换光致发光的新型安全标签。为了制造这些标签，采用飞秒激光选择性地辐照双层 Er/Si 薄膜，这是通过将 Er 掺入硅基体和硅层结晶来实现的。对激光诱导加热的研究表明，它在硅中产生了光学活性的铒中心，在 1530nm 处提供了稳定且增强的光致发光。该技术用于创建两种类型的防伪标签。第一种类型是通过单步直接激光写入发光区域来实现的，并用光学显微镜检测到在形成所需图像的薄膜中形成的孔。第二种类型具有更高的安全性，通过添加其他制造步骤来实现，包括 Er 层的化学蚀刻和在初始记录图像上激光写入额外的非发光孔。在对标签的发光孔进行 525nm 激光激发时，可以看到重复所需数据的光致发光图像。所提出的标签易于扩展，具有标记商品、证券和奢侈品的潜力。
