1,721,063 research outputs found
Enhancing raman scattering without plasmons: unprecedented sensitivity achieved by TiO2 shell-based resonators
No full textA remarkable enhancement of Raman scattering is achieved by TiO2 shell-based spherical resonators in the absence of plasmonic enhancers. This effect is ascribed to the synergistic combination of high refractive index of the shell layer, multiple light scattering through the spheres, and related geometrical factors and can be exploited to fabricate a new generation of self-diagnostic, recyclable SERS-active substrat
Plasmonic heating assisted deposition of bare Au nanoparticles on titania nanoshells
No full textA very simple procedure for depositing bare Au nanoparticles onto the surface of oxide nanoshells is presented. This method is based on plasmonic heating assisted processes which are triggered by a continuous wave laser source that is focused through the objective of a Raman microscope. The Au nanoparticles are obtained upon laser irradiation of colloidal crystals consisting of Au semishells buried in titania overlayers. SERS activity and heating effects induced by laser irradiation are demonstrated in a series of microRaman experiments
Writing, Self-Healing, and Self-Erasing on ConductivePressure-Sensitive Adhesives
No full textA simple strategy for enabling conductive pressure sensitive adhesives (PSAs) to work as light-responsive materials is reported. Direct laser-writing of PSA substrates was achieved by means of a continuous-wave He-Ne laser focused through the objectives of an optical microscope. This approach takes advantage of cooperative interplay between viscoelastic properties of PSAs and enhanced thermal conductivity provided by an extra overlayer of gold. In particular, the thickness of the gold layer is a crucial parameter for tuning the substrate responsiveness. Self-healing and self-degradation processes can be exploited for controlling the lifetime of the written information, whereas additional protective coatings can be introduced to achieve permanent storag
Exploiting optothermal conversion for nanofabrication: site-selective generation of Au/TiO2 inverse opals
No full textSurface Chemical Analysis of Ceramics and Ceramic‐Enhanced Analytics
No full textThis chapter gives a brief overview of methods used to analyze functionalized surfaces with a comparison among different working principles and performances. The schematic, yet nonexhaustive summary, can guide a nonexpert reader in evaluating potential and limitations of some of the most used analytical tools. Most significant methods such as electron and X-ray spectroscopy, secondary ion mass spectrometry, and vibrational spectroscopy (Raman and Infrared) are in focus. These techniques will be described in general terms, to provide a concise overview of their working principles, capabilities, and applications. The second part of this chapter will present exciting examples in which ceramic nanostructures are exploited to enhance the chemical sensitivity in optical sensing, vibrational spectroscopy (IR and Raman), and mass spectrometry and enable novel surface analytical tools based on their versatile properties
Self-healing nanocomposites. Role anda activation of inorganic moieties and hybrid nanophases
No full textUsing plasmonic heating of gold nanoparticles to generate local SER(R)S-active TiO2 spots
No full textThe plasmonic heating generated by laser irradiation of gold nanoparticles was exploited for fabricating SER(R)S-active anatase spots
Metal Oxide Microrings with Femtoliter Capacity for Raman Microspectroscopy
No full textA simple strategy, based on ultrafast heating of polystyrene microspheres infiltrated with a zinc acetate solution, is employed here for preparing ZnO microcontainers with femtoliter capacity. Their potential exploitation in micro-Raman assays for basic studies in bio- and nanotechnology is tested in different proof-of-concept experiments concerning the in situ analysis of L-glutathione crystals and gold-yeast cytochrome c bioconjugates. The ZnO microcontainers are also used as scaffolds for atomic layer deposition of TiO 2 overlayers with a fine-tuning of thickness and morphology. The resulting ZnO/TiO 2 heterostructures are tested in different photocatalytic experiments involving degradation and laser-induced conversion of methylene blue
Enhanced Raman Scattering with Dielectrics
No full textDielectrics represent a new frontier for surface-enhanced Raman scattering. They can serve as either a complement or an alternative to conventional, metal-based SERS, offering key advantages in terms of low invasiveness, reproducibility, versatility, and recyclability. In comparison to metals, dielectric systems and, in particular, semiconductors are characterized by a much greater variety of parameters and properties that can be tailored to achieve enhanced Raman scattering or related effects. Light-trapping and subwavelength-focusing capabilities, morphology-dependent resonances, control of band gap and stoichiometry, size-dependent plasmons and excitons, and charge transfer from semiconductors to molecules and vice versa are a few examples of the manifold opportunities associated with the use of semiconductors as SERS-active materials. This review provides a broad analysis of SERS with dielectrics, encompassing different optical phenomena at the basis of the Raman scattering enhancement and introducing future challenges for light harvesting, vibrational spectroscopy, imaging, and sensing
Laser-induced modification of polymeric beads coated with gold nanoparticles
No full textA direct laser writing method for modifying colloidal crystals and single colloids is presented. This method takes advantage of the highly efficient conversion of photons into heat exhibited by gold nanoparticles. The easy control of experimental parameters allowed control of the spatial resolution of the patterns. This may open the way to practical applications for the technology
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