We demonstrate that colloidal Cu2–xSe nanocrystals exhibit a well-defined infrared absorption band due to the excitation of positive charge carrier oscillations (i.e., valence plasmon mode), which can be tuned reversibly in width and position by varying copper stoichiometry. The value x could incrementally varied from 0 (no absorption, then broad peak at 1700 nm) 0.4 (narrow 1100 oxidizing Cu2Se (upon exposure either oxygen or Ce(IV) complex), it restored back zero addition Cu(I) complex....

We present a facile and reproducible method for synthesizing monodisperse platinum (Pt) spheres with sizes ranging from 10 to 100 nm in diameter exceptionally small standard deviations of 3% large spheres. The reaction takes place aqueous solution using multistep seed-mediated approach. Pt nanospheres consist several crystallites resulting surface roughness 5-10 nm. Extinction spectra are measured particles dispersed water calculated single which found be excellent agreement. obtain linear...

We report on the near-field coupling of individual gold nanoantennas arranged in tip-to-tip dimer configuration, leading to strong electromagnetic field enhancements infrared, which is great interest for sensing applications such as surface-enhanced infrared spectroscopy. quantitatively evaluated enhancement vibrational excitations a 5 nm thick test layer 4,4'-bis(N-carbazolyl)-1,1'-biphenyl function different gap sizes. The dimers with smallest gaps under investigation (∼3 nm) lead more...

Near-field coupling of a single gold nanoparticle (GNP) to fluorescent molecule is investigated here for varying separation d between the two. While emission quantum efficiency coupled system generally decreases d!0, pronounced near-field enhancement observed under certain conditions, partly outweighing loss at small distances. We report on optimizing these conditions by excitation field direction and three-dimensional relative configuration GNP fluorophore. Furthermore, we examine how...

We demonstrate the imaging of ferroelectric domains in BaTiO3, using an infrared-emitting free-electron laser as a tunable optical source for scattering scanning near-field microscopy and spectroscopy. When is tuned into spectral vicinity phonon resonance, can be resolved due to anisotropy dielectric properties material. Slight detuning wavelength gives rise contrast reversal clearly evidencing resonant character excitation. The domain shows that orientation tensor with respect sample...

In this paper, we report on the manipulation of near-field coupling in individual gold nanoantenna dimers resonant infrared (IR) spectral range. Photochemical metal deposition onto lithographically fabricated nanoantennas is used to decrease gap between antenna arms down below 4 nm, as confirmed by finite-difference time-domain simulations. The increased plasmonic region leads a shift surface plasmon resonances lower energies well appearance hybridized modes. All occurring electron...

The distance- and polarization-dependent near-field enhancement of two coupling metal nanoparticles (MNPs) is analyzed by means the novel scanning particle enhanced Raman spectroscopy (SPRM) technique. In contrast to single MNP experiments, between dissimilar MNPs as followed here leads a hot spot yielding an extra factor 17.6 20, proven both in experiment theory. Three-dimensional electric field calculations for our two-particle arrangements were performed using semianalytical...

We report on the in-situ controlled tuning of particle gap in single pairs gold nanodisks by photochemical metal deposition. The optically induced growth nanodisk dimers fabricated electron beam lithography leads to a decrease interparticle width down 0 nm. Due increasing size and stronger plasmonic coupling, smooth redshift localized surface plasmon (LSP) resonances is observed such during process. width, hence LSP resonance, can be tuned any desired spectral position. experimental results...

We report on the spectrally controlled photochemical tuning of size, shape, and localized surface plasmon resonances individual gold nanoparticles. Single spheres, extracted from a colloidal solution, elongated nanodiscs, fabricated by electron beam lithography, were exposed to salt solution while being illuminated one focused 532-nm laser beam. The reduction tetrachloroaureate complexes, followed subsequent agglomeration atoms at particle surface, lead well-controlled single-particle...

We report on a universal technique which allows us to precisely manipulate the diameter of metal nanoparticles in two-dimensional particle arrays. The approach is demonstrated here for hexagonally ordered gold nanoparticle arrays fabricated by means diblock copolymer micelle lithography (BCML). particles are used as nucleation centers seed-mediated photochemical deposition, whereby increases. Repeatedly combining growth with thermal annealing steps additionally facilitates controlling shape...

Abstract Aerogels can bridge the nanoscopic to macroscopic world. One physical phenomenon typically limited world is occurrence of localized surface plasmon resonances (LSPRs), which are observed in conductive nanoparticles. Once brought into close contact, assemblies or superstructures these nanoparticles often lose their plasmonic properties transition stage towards bulk material. Therefore, LSPRs not objects. The present work aims at voluminous nanoparticle-based aerogels with optical...

The in-line monitoring of ethanol concentration in liquids is a crucial part process breweries and distilleries. Current methods are based on infrared spectroscopy, which time-consuming costly, making these unaffordable for small middle-sized companies. To overcome problems, we presented small, compact, cost-effective sensing method the content, nanostructured, plasmonically active sensor substrate. substrate coated with an ethanol-sensitive hydrogel, polyacrylamide bisacrylamide, induces...

We report on the implementation of metal nanoparticles as probes for scattering and apertureless near-field optical investigations in mid-infrared (mid-IR) spectral regime. At these wavelengths, an efficient electric-field confinement is necessary achieved here through a gold nanoparticle 80 nm diameter (Au80-MNP) acting antenna. The Au80-MNP attached to standard AFM cantilever used spatial manipulator. When approached sample surface while being illuminated with infrared beam, produces...

In this report, we experimentally demonstrate that single platinum nanoparticles exhibit the necessary catalytic activity for optically induced reduction of H[AuCl4] complexes to elemental gold. This finding is exploited parallel Au encapsulation FePt arranged in a self-assembled two-dimensional array. Magnetic force microscopy reveals thin gold layer formed on particles leads strongly increased long-term stability their magnetization under ambient conditions.

We report the synthesis of plasmonic Cu2-x Se@ZnS core@shell nanoparticles (NPs). used a shell growth approach, starting from Se NPs that have been shown before to exhibit localized surface plasmon resonance (LSPR). By careful planning we avoided cation exchange reactions and received that, after oxidation under air, strong LSPR in NIR. Interestingly, crystalline, closed ZnS grew with variable thickness still allowed slow core ambient conditions, while was effectively protected reduction,...

Hydrogels are cross-linked polymer networks able to absorb or release large amounts of water. The water uptake is associated with a considerable volume change but also changes optical properties like the refractive index. swelling can be excited by spectrum different physical (e.g. temperature, electrical voltage, magnetic field) and chemical factors pH value, concentrations biochemical species). particular sensitivity adjusted tailoring composition hydrogel via its functionalization. If...

We report on tuning the plasmonic properties of gold nanoantenna arrays resonant in infrared (IR) spectral region. In particular, we achieve a manipulation antenna resonance by decreasing separation distance via photochemical metal deposition. Narrowing gaps is monitored using scanning electron microscopy, while increased coupling and an associated red-shift plasmon observed microscopic IR spectroscopy. Since smaller gap sizes lead to enhanced electric fields between arms, propose deposition...

Abstract. Photoelasticity is considered a useful measurement tool for the non-destructive and contactless determination of mechanical stresses or strains in production silicon wafers. It describes change indices refraction material when mechanically loaded. As has diamond lattice structure, stress-dependent refractive varies with loading direction. In this work, an anisotropic stress-optic law derived, corresponding stress-optical parameters are measured using Brazilian disc test. The were...

With the increasing number of electrical devices, especially electric vehicles, need for efficient recycling processes components is on rise. Mechanical lithium-ion batteries includes comminution electrodes and sorting particle mixtures to achieve highest possible purities individual material (e.g., copper aluminum). An important part quantitative determination yield recovery rate, which required adapt different feed materials. Since this usually done by particles manually before determining...

Abstract. The continuous monitoring of industrial and environmental processes is becoming an increasingly important aspect with both economic societal impact. So far, spectral-optical sensors their outstanding properties in terms sensitivity reliability have not been considered as a potential solution because the cost-intensive bulky readout hardware. Here we present card-size, inexpensive, robust platform based on wavelength-sensitive photodiode. In test characterization experiments...

A recent approach to measure electron radiation doses in the kGy range is use of phosphors with an irradiation dose-dependent luminescence decay time.

Abstract. Tracking and tracing are a key technology for production process optimization subsequent cost reduction. However, several industrial environments (e.g. high temperatures in metal processing) challenging most part-marking identification approaches. A method printing individual part markings on components data matrix codes (DMCs) or similar identifiers) with chemical resistance has been developed based drop-on-demand (DOD) print special ink dispersions submicrometer-sized ceramic...

We report on an unique optical method which facilitates detection of ferroelectric (FE) domain orientation the subwavelength scale. The FE material interest is decorated with Au nanoparticles 100nm diameter and then completely covered a thin film birefringent liquid-crystal (LC) molecules. latter align to surface in accordance domain-specific electric stray field, causes characteristic spatial dielectric tensor ε̂m LC layer. As their spectral response strongly depends constant surrounding...