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Recent Trends on Smart Bioresponsive Polymeric Materials
Published in Moayad N. Khalaf, Michael Olegovich Smirnov, Porteen Kannan, A. K. Haghi, Environmental Technology and Engineering Techniques, 2020
Kalpana N. Handore, Sumit B Sharma, Santosh Mishra, Vasant V. Chabukswar
A surface-sensitive characterization based on the evanescent field of the surface plasmon. The latter is an electromagnetic wave traveling along the interface between a metal and a dielectric. Its electric field decays exponentially into both materials over a distance of a few hundred nanometers and the wave has a finite propagation length due to damping processes in the metal. The resulting data are a direct measure of the local average refractive index of the dielectric close to the surface, and with Fresnel calculations either the thickness or the refractive index of thin films at an interface can be determined. Furthermore, a time-dependent measurement mode enables the detection of changes in the local average dielectric constant due to the adsorption of molecules onto the surface or changes in film properties due to an external trigger.59 Surface plasmons are the quanta of charge-density waves of free electrons in a metal propagating along the interface of a metal and a dielectric medium such as buffer or air. The electromagnetic field of these surface waves reaches its highest intensity at the metal surface and decreases exponentially into the adjacent phase. Therefore, it is influenced by the optical properties of this phase. The strong dependence of the surface plasmons on the refractive index of the dielectric medium can be used for sensor development purposes.66–68
Reactivity and Bio Samples Probed by Tip-Enhanced Raman Spectroscopy
Published in Marc Lamy de la Chapelle, Nordin Felidj, Plasmonics in Chemistry and Biology, 2019
Zhenglong Zhang, Robert Meyer, Volker Deckert
Surface plasmons excited on metal nanostructures have been used to initiate chemical reactions, which are so-called plasmon driven/catalyzed chemical reactions, where the plasmonic nanostructure acts as the catalytic active site [9–11]. The hot electrons, generated from plasmon decay, work as a main catalyst in plasmon driven/catalyzed chemical reactions. Hot electrons can scatter into an excited state of the absorbed molecules triggering a chemical reaction by reducing the activation energy. This is also called hot electron–induced chemical reaction. Hot electron chemistry has drawn great attention from materials, energy, sensing, and catalysis applications, which has a great potential for overcoming many intrinsic limitations, and gains significant attention due to its high throughput and low energy requirements as reported in studies on molecular dimerization and dissociation reactions, e.g., dissociation of hydrogen [12, 13], water [14, 15], and hydrocarbon conversion, etc. [16, 17].
Nanodevices for Early Diagnosis of Cardiovascular Disease: Advances, Challenges, and Way Ahead
Published in Alok Dhawan, Sanjay Singh, Ashutosh Kumar, Rishi Shanker, Nanobiotechnology, 2018
Alok Pandya, Madhuri Bollapalli
Surface plasmon resonance is a charge–density oscillation that may exist at the interface of two media with dielectric constants of opposite signs, like a metal and a dielectric. When the surface of a thin metal film is excited by an incident beam of light with a suitable wavelength at a specific angle, an evanescent electromagnetic field is generated and is described as a charge density oscillation occurring at the interface between two media of oppositely charged dielectric constants. Dutra et al. (2007) developed SPR supported detection of only surface-confined molecular interactions occurring on the transducer surface. A basic SPR immunosensor consists of a light source, a detector, a transduction surface, a prism, a biomolecule (antigen or antibody), and a flow system. Commonly, a thin gold film with thickness from 500 to 1000 Å is deposited on a glass slide, then optically coupled to a glass prism through a refractive index matching that of oil. Plane polarized light is directed through a glass prism to the gold/solution dielectric interface over a wide range of incident angles and the intensity of the resulting reflected light is measured against the incident light angle with a detector. A minimum in the reflectivity is observed at which the light waves are coupled to the oscillation of surface plasmons at the gold/solution interface. An SPR angle is the angle at which minimum reflectivity occurs. The critical angle is very sensitive to the dielectric properties of the medium adjacent to the transducer surface, apart from its dependence on the wavelength and polarization state of the incident light.
Sensitivity enhancement of fiber surface plasmon resonance (SPR) sensor based upon a gold film-hexagonal boron nitride—molybdenum disulfide structure
Published in Instrumentation Science & Technology, 2022
Haizhou Zheng, Jiayang Yang, Qi Wang, Bin Feng, Ruifeng An
Surface plasmon resonance refers to the phenomenon caused by the coupling between polarized light and metal surface plasmon waves, which greatly reduces the reflected light intensity at the interface between metal and medium, thus forming a resonance trough.[6–9] The position of the resonant trough changes with the refractive index (RI) of the medium.[10] When a marker in the solution binds to the sensor, the refractive index of the medium changes, causing a migration in the SPR trough that may be monitored.[5] However, due to the low photoelectric conversion efficiency, the ordinary instant plasmon resonance sensor cannot fully absorb flooded light and is unable determine small molecules and low concentrations.[11]
Perovskite solar cells: importance, challenges, and plasmonic enhancement
Published in International Journal of Green Energy, 2020
Moshsin Ijaz, Aleena Shoukat, Asma Ayub, Huma Tabassum, Hira Naseer, Rabia Tanveer, Atif Islam, Tahir Iqbal
Localized surface plasmons originate when the light interacts with a metal nanostructure. The light that interacts with the metal nanostructures has a large wavelength compared to nanostructures, this gives rise to plasmon oscillation around nanostructure(Ijaz et al. 2020; Iqbal et al. 2020). Another kind of plasmon called surface wave plasmon, which is also called bounded plasma in which the waves that re guided by plasma sustain it(Popov Oleg 1995). Absorption and light scattering by surface plasmons is governed by Mie theory (Mie 1908). Plasmon modes can easily be explained through hybridization theory for nanostructures. (Prodan et al. 2003). Light scattering is a technique to study the internal structure of matter such as plasma by illuminating with EM radiations to which the matter is completely transparent. The radiations emitted in this case are due to the interaction between incident radiation and the free electrons in plasma. The angular distribution of the scattered radiation provides information about electron density. Measuring light scattering enables us to get dynamic understanding of plasma without destroying it. (Evans and Katzenstein 1969)
Applications and challenges of elemental sulfur, nanosulfur, polymeric sulfur, sulfur composites, and plasmonic nanostructures
Published in Critical Reviews in Environmental Science and Technology, 2019
Yong Teng, Qixing Zhou, Peng Gao
Scientists have long been interested in the interaction of light with matter. Of particular interest has been the condition where the size of a material is reduced to less than or equal to the wavelength of incident light (Goswami et al., 2010; Thera et al., 2017). Plasmonic nanostructures have been developed based on a compelling analogy between plasmon resonances of nanomaterials (the collective oscillations of free charges) and wave functions of atoms and molecules (Wang, Brandl, Nordlander, & Halas, 2007). Plasmonics have realized to merge the field of optics and nanoelectronics confining light to the nanometer scale. There are various potential plasmonic materials including metals, metal alloys, and heavily doped semiconductors (West et al., 2010). Especially, metallic nanostructures include morphologies of nanoshells, nanoeggs, nanomatryushkas, nanorices, dimers, trimers, quadrumers assmbilies, and metallic films, and are also the major candidates of plasmonic nanomaterials (Wang et al., 2007). It is perhaps that after some modifications, sulfur composite nanostructures could be a kind of promising plasmonic nanomaterials as well.