Gas Sensors Based on Localized Surface Plasmon Resonances: Synthesis of Oxide Films with Embedded Metal Nanoparticles, Theory and Simulation, and Sensitivity Enhancement Strategies

Abstract

This work presents a comprehensive review on gas sensors based on localized surface plasmon resonance (LSPR) phenomenon, including the theory of LSPR, the synthesis of nanoparticle-embedded oxide thin films, and strategies to enhance the sensitivity of these optical sensors, supported by simulations of the electromagnetic properties. The LSPR phenomenon is known to be responsible for the unique colour effects observed in the ancient Roman Lycurgus Cup and at the windows of the medieval cathedrals. In both cases, the optical effects result from the interaction of the visible light (scattering and absorption) with the conduction band electrons of noble metal nanoparticles (gold, silver, and gold–silver alloys). These nanoparticles are dispersed in a dielectric matrix with a relatively high refractive index in order to push the resonance to the visible spectral range. At the same time, they have to be located at the surface to make LSPR sensitive to changes in the local dielectric environment, the property that is very attractive for sensing applications. Hence, an overview of gas sensors is presented, including electronic-nose systems, followed by a description of the surface plasmons that arise in noble metal thin films and nanoparticles. Afterwards, metal oxides are explored as robust and sensitive materials to host nanoparticles, followed by preparation methods of nanocomposite plasmonic thin films with sustainable techniques. Finally, several optical properties simulation methods are described, and the optical LSPR sensitivity of gold nanoparticles with different shapes, sensing volumes, and surroundings is calculated using the discrete dipole approximation method.

Maximizing the Surface Sensitivity of LSPR Biosensors through Plasmon Coupling—Interparticle Gap Optimization for Dimers Using Computational Simulations

“…Changes either in the bulk refractive index of the surrounding liquid or gas or in molecular events such as bioreceptor–analyte binding on the surface of the nanoparticles cause a detectable redshift in their light extinction spectrum [ 3 ]. Several excellent review papers can be found that demonstrate how to utilize this effect in a large variety of sensing applications [ 4 ], from gas sensing [ 5 ] to chemical and biosensing [ 6 , 7 ], e.g., for biomarker [ 8 , 9 , 10 ] or nucleic acid detection [ 11 , 12 ].…”

Design of Two-Mode Spectroscopic Sensor for Biomedical Applications: Analysis and Measurement of Relative Intensity Noise through Control Mechanism

“…In LabVIEW, the quasi-parallelism is easily performed by two separate loops [51,55]. This is why the complex representation of a pseudo code is not used at this point.…”

Recent Developments in Plasmonic Sensors of Phenol and Its Derivatives

“…Moreover, regarding amplification of signals obtained by plasmonic materials, graphene-based nanostructure composites can significantly increase the sensitive detection of analytes up to fM [90]. Owing to their sensitivity and the selectivity of the spectral location of the refractive index, SPR-based optical sensors have been widely investigated in sensing applications such as mercury ion detection [8,91], CO 2 detection [1], and gas sensors [2]. Some special emphasis on plasmonic nanostructures has been developed for the fabrication of novel surfaces, exposing high SPR-based optical sensors for phenolic compounds, such as GNP impregnation in TiO 2 structure-assisted hydroquinone detection [24], Au-and tyrosinase-modified graphene oxide film-introduced detection of phenol [9], and polymeric film-based phenol determination [92].…”

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