Hierarchical Au Nanoisland Arrays for Anticounterfeiting Surface-Enhanced Raman Scattering Stamps

Abstract

Plasmonic nanostructures of hierarchy allow for the integration of the functions of different domains and, importantly, provide built-in nanogaps and hotspots due to the intrinsic coupling effect. Although they are badly needed for a range of applications, including surface-enhanced spectroscopies, chem/biosensing, and others, simple and fast preparation of plasmonic hierarchical nanostructures remains a challenging goal. Here, the growth of hierarchical Au nanoisland arrays in a reactant in/target produced fashion is communicated. By a single-step quick injection, uniform Au nanoisland arrays with intense built-in hotspots could be produced within minutes through competitive balance between the reaction rate and seed surface passivation using a strong binding ligand. The experimental results and theoretical simulations revealed a strong electromagnetic enhancement effect of the Au nanoisland arrays. Stable anticounterfeiting SERS labels were realized by stamping the nanoisland array-based ink on an ordinary paper, by which dyes of similar appearance can be easily discriminated.

Recent Progress in SERS‐Based Anti‐counterfeit Labels

“…The morphology of these nanomaterials varied greatly and includes nanosphere, nanostar, nanowire, nanopillar, nanoisland, aggregate, and metafilm. [22,24,[27][28]32,90] The plasmonic coupling in these materials is quite different and results in their varied enhancement factors. Overall, nanoparticles with a roughened surface have demonstrated strong SERS signals with a higher enhancement factor than those with a smooth surface.…”

“…The other way is to synthesize gold or silver nanoparticles via wet chemistry. [23,24,31,90] Then, these nanoparticles were deposited or self-assembled to form a label. This method can have good control of the morphology of nanostructures.…”

A microscopic survey on microplastics in beverages: the case of beer, mineral water and tea

“…Investigations on 15 types of beers produced worldwide and four types of Chinese tea leaves revealed the ubiquitous occurrence of microplastic pollution to all the daily beverages, despite characteristics of number and distribution for the shape of microplastics in each beverage. By coupling with the finger-printing feature of Raman spectroscopy, 13–15 the presence of polystyrene (PS) and polypropylene (PP) microplastics in beers, PP in bottled mineral water, and polyethylene (PE) and polyethylene terephthalate (PET) in tea leaves were identified (Fig. 1).…”

DNA-Functionalized Silver Nanoparticles in an Alcoholic Solvent for Environment-Dictated Multimodal Actuation

“…Actuators are capable of transforming external energy and stimuli into physical motion and are badly needed for the construction of various intelligent biomimetic systems. 1,2 Down to the nanoscale, plasmonic nanoactuators that afford control of nanoparticle movement and assembly further promise advanced uses in nanorobotics, 3 information storage, 4 and smart windows. 5,6 In the past few years, the development of plasmonic actuators has undergone a quiet revolution.…”

“…Actuators are capable of transforming external energy and stimuli into physical motion and are badly needed for the construction of various intelligent biomimetic systems. , Down to the nanoscale, plasmonic nanoactuators that afford control of nanoparticle movement and assembly further promise advanced uses in nanorobotics, information storage, and smart windows. , In the past few years, the development of plasmonic actuators has undergone a quiet revolution. Nanoactuators have been designed using a wide range of hybrid materials, such as polymers, hydrogels, and inorganic nanoparticles. , Responsive actuations of those materials have been achieved using a range of physical and chemical stimuli. − For instance, poly­( N -isopropylacrylamide) and azobenzene moieties have been employed for control of interparticle steric forces, which are responsive to temperature and light, respectively. , Numerous pH oscillators can also be enabled with different charged ligands through the modulation of electrostatic interactions. − These findings have convinced us of the importance of surface ligands in tailoring the physicochemical property and spatial configuration of nanoparticle actuators in response to an environmental stimulus.…”