Designed Growth of AgNP Arrays for Anti-counterfeiting Based on Surface-Enhanced Raman Spectroscopy Signals

Abstract

Based on etched PS sphere arrays, the different growths of Ag nanoparticles with tunable LSPR are designed when SiO 2 -25 nm/Ag-30 nm/SiO 2 -100 nm sandwich nanocavity structures are annealed at 500 °C, including the hexagonal silver nanoparticle rings, circular silver nanoparticle rings, and aggregated silver nanoparticles. The uniformity of particle size and regularity of position generate enhanced electromagnetic field and good surface-enhanced Raman spectroscopy signals as confirmed by UV−vis observation and finite difference time domain method simulation. The developed nanostructures are effectively used as stable, nonreproducible, and markable anti-counterfeiting signs.

Raman encoding for security labels: a review

“…67 In a special example, Yang et al can generate Ag hexagonal rings, Ag circular rings, and Ag aggregates with random features by annealing the silver layer in the silica layer, and these nanoparticles with irregular morphology will bring a random Raman signal output for PUF security labels. 74 Different from the two previous examples, this method does not directly use Raman-active materials as the preparation object of random features. Therefore, the introduction of signal molecules is necessary.…”

“…In a zero-dimensional space, the encoding capacity depends only on the number of possible spectra. 73,74 However, due to the high similarity in the peak position of these Raman spectra, the encoding capacity brought by the random features is relatively limited, and is easily affected by the acquisition conditions. How to accurately locate the collection point on the same point of the security label is also a challenge, which will affect the repeated verification of the label.…”

Bioinspired Multifunctional Silver Nanoparticles for Optical Sensing Applications: A Sustainable Approach

“…The sandwich structures of silver nanoparticles with hexagonal and circular rings imply that uniformity and regularity in size parameters will generate an improved optical field for MEF. 161 The increased intensity and photostability of the fluorophore, [Ru(bpy) 3 ] 2+ , are realized on the Ag surface due to the alteration of the decay rate of the Ru molecule. The potentiostatic electrodeposition process used for the production of engineered nanobased metallic surfaces is found in fluorescence-based applications.…”

“…The varied growth of silver nanoparticles was studied by adjusting the LSPR with silicon dioxide. The sandwich structures of silver nanoparticles with hexagonal and circular rings imply that uniformity and regularity in size parameters will generate an improved optical field for MEF . The increased intensity and photostability of the fluorophore, [Ru(bpy) 3 ] 2+ , are realized on the Ag surface due to the alteration of the decay rate of the Ru molecule.…”

Plasmonic Biosensors with Nanostructure for Healthcare Monitoring and Diseases Diagnosis

“…Ordered and uniform plasmonic array structures can be prepared based on closely arranged micro-spheres formed by capillary force between colloidal spheres [ 41 , 42 ]. Colloidal spheres can be self-assembled into monolayer or multilayer and then combined with deposition, RIE, wet etching, annealing and other methods to produce a variety of complex periodic two-dimensional or three-dimensional plasmonic structures [ 43 , 44 , 45 ], such as nano holes, nano bowls, nano columns, nano cones and so on [ 46 ].…”