(Nanowerk News) The use of photoluminescent substances in the realm of information security is increasingly attracting attention. Various anti-counterfeiting modalities, including watermarks, two-dimensional codes, and luminous printing, have been innovatively developed. Nonetheless, the common use of monochromatic fluorescent materials has presented considerable challenges because of their susceptibility to counterfeiting.
An ensemble of researchers from the Suzhou Institute of Biomedical Engineering and Technology (SIBET), in association with the Chinese Academy of Sciences, has pioneered the development of glow-in-colour nanocomposite materials. This feat was achieved through direct hydrothermal techniques, using silanes as luminescent precursors for the synthesis of silicon-based compounds, then finding applications in the field of information security.
The results of the investigation are disclosed in Journal of Chemical Engineering (“Multi-Color Room-temperature Fluorescent Silicon-Nanodot Based Nanocomposites with silane tuning and applications for 5D information encryption”).
Materials that exhibit room temperature fluorescence (RTP) have found a wide range of applications in bioimaging, information security, and lighting, mainly attributed to their unique glow characteristics.
Lead researcher, DONG Wenfei, noted that traditional synthesis methodologies mostly use inorganic compounds containing rare earth ions or precious metal complexes to achieve glow. This approach, however, invariably results in substantial biological toxicity and an expensive synthesis process.
As DONG explains, two conditions are integral to a successful synthesis: effective crossing of the exciplex between systems and a structurally rigid framework that ensures the excited triplet state of the exciplex remains stable.
With this in mind, the researchers chose 3-Aminopropyl triethoxysilane (APTES) and N-(3-(Trimethoxysilyl)propyl)ethylenediamine (DAMO) as sources of silicon, incorporating urea as an additional precursor. This selection led to the creation of optically stable cyan and yellow RTP materials, respectively.
The fabrication process employs a one-step hydrothermal technique, which not only effectively avoids the drawbacks associated with the two-step method but also easily generates nanodots in-situ and embeds them in the matrix.
The resulting anti-counterfeiting strategy promises sophisticated encryption scenarios. Here, only interference information can be obtained in ultraviolet and incandescent irradiation modes. Thus, filters become essential to accurately decipher encrypted content, thereby providing superior concealment of the correct information.
Dr. ZAN Minghui, corresponding author of the study, noted that their approach is widely applicable. This standard methodology underscores the potential of silane in constructing multi-functional phosphorescent materials, offering new design principles for synthesizing colorful incandescent materials.
Ultimately, this research underscores the feasibility of silane as a means of creating multi-colored fluorescent materials. It also offers innovative design principles and insights for fabricating silicon-based incandescent materials for pioneering applications.