澳大利亚昆士兰大学Xu Jingsan团队报道了用于防伪加密的氮化碳薄膜动态光致发光开关。相关研究成果发表在2024年8月12日出版的《结构化学》。

随着假冒行为的日益猖獗，光致发光（PL）在防伪和加密方面的应用越来越多。然而，常见的发光加密技术基于静态PL测量，很容易被伪造。

该文中，研究人员开发了一种热气相沉积（TVD）方法，使用melem作为独特的起始材料来合成具有独特动态PL开关特性的高度均匀的氮化碳薄膜。在被白色LED照射后，CN薄膜的蓝色PL强度显著增加，然后在黑暗中逐渐减弱，显示出优异的可恢复性。

实验结果证明，CN薄膜的结构中含有氰基，密度泛函理论（DFT）计算表明，氰基的集成导致CN带隙内存在陷阱，这表明动态PL开关效应本质上与陷阱态的充满度有关。因此，研究人员开发了一种先进的发光设备，用于通过受控照明安全传输加密信息。它可以很容易地用便携式UV（365 nm）灯读取，并使用白色LED有效擦除，从而防止信息泄露，在许多应用中显示出巨大的潜力。

附：英文原文

Title: Dynamic photoluminescence switching of carbon nitride thin films for anticounterfeiting and encryption

Author: Hang Meng, Bicheng Zhu, Ruolun Sun, Zixuan Liu, Shaowen Cao, Kan Zhang, Jiaguo Yu, Jingsan Xu

Issue&Volume: 2024-08-12

Abstract: Photoluminescence (PL) has been increasingly applied in anticounterfeiting and encryption as counterfeiting becomes more prevalent. However, common luminescent encryption techniques are based on static PL measurements and are easy to counterfeit. In this work, we have developed a thermal vapor deposition (TVD) approach using melem as the unique starting material to synthesize highly homogeneous carbon nitride thin films featuring unique dynamic PL switching properties. After being irradiated by a white LED, the blue PL intensity of the CN film increases significantly and then fades in darkness, demonstrating excellent recyclability. Experimental results prove that CN films contain cyano groups in the structure, and density functional theory (DFT) calculations indicate that the integration of cyano groups results in traps within the bandgap of CN, suggesting that the dynamic PL switching effect is essentially associated with the fullness of the trap states. We have therefore developed an advanced luminescent device for the secure transmission of encrypted information through controlled illumination. It can be easily read with a portable UV (365 nm) lamp and effectively erased using the white LED, thereby preventing information leakage and showing great potential for many applications.

DOI: 10.1016/j.cjsc.2024.100410

Source: http://cjsc.ac.cn/cms/issues/671