Manganese-doped zinc germanate phosphors with vivid luminescent properties for anti-counterfeit applications

Fluorescent materials are commonly used in optical labels for anti-counterfeiting purposes. However, these well-known materials can be vulnerable to forgery. It is thus essential to develop new types of luminescent materials with unique optical properties. In this paper, we prepared metal-doped phosphor materials with an inorganic matrix using a high temperature solid-state reaction. The synthesized Mn-doped zinc germanate (ZGO:Mn) phosphors were characterized using various techniques, such as X-ray powder diffraction and photoluminescence spectroscopy, in order to understand their structural and optical properties. The ZGO:Mn phosphors exhibit green color fluorescence, persistent luminescence, and photostimulated luminescence (PSL), which are ideal for anti-counterfeiting applications. Several examples of using the PSL active materials on various substrates demonstrate their capability to prevent counterfeiting and forgery. We further showed that an iPhone can be used to reveal the ZGO:Mn-based security labels. This study contributes to the exploration of novel security materials and offers practical implications for the development of security and authentication technologies.