- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Photocatalytic Degradation of Bisphenol A Induced by Dense Nanocavities Inside Aligned 2D-TiO2 Nanostructures
摘要： The preparation of materials with aligned porosity in the nanometer range is of technological importance for a wide range of applications in molecular filtration, biomaterials and catalysis. Herein we present the advantages offered by cryo – lyophilisation technique as a smart and green non-standard concept to produce dense regular polyhedral nanocavities inside the 2D TiO2 nanosheets. Hierarchical morphologies of nanocavities start to appear at temperature higher than 800 °C and are strongly influenced by polymorph TiO2 evolution competing reactions. The small angle X-ray scattering (SAXS) analysis confirms self-assembled 3D nanocavities with size range from 5 to 10 nm in both length and width, and depth ~ 3.6 nm formed after realising of the confined ice-water. It was found that nanocavities enhance significantly the absorption properties of TiO2 in the UV region, thereby providing a new approach to increase the photoreactivity of 2D TiO2 nanosheets. The annealed precursors containing aqueous solution of peroxo polytitanic acid (PPTA) at 800 °C exhibited the highest photoactivity in degrading bisphenol A (BPA) due to evenly distributed nanocavities inside single anatase TiO2 nanocrystals interconnected and aligned onto the 2D TiO2 nanosheet arrays.
关键词： emerging pollutants,nanoconfined water,photocatalysis,nanocavities,freeze-drying,anatase TiO2
更新于2025-09-23 15:23:52
-
Effective light polarization insensitive and omnidirectional properties of Si nanowire arrays developed on different crystallographic planes
摘要： In this paper, fabrication of vertical Si nanowire arrays (SiNWAs) by a facile metal assisted electroless etching approach on different crystallographic planes of Si has been reported. A very low specular reflectance (Rspec) of 0.04% and 0.03% has been achieved in the whole visible range for SiNWAs grown on Si(100) and Si(111) oriented substrates, respectively. High broadband enhancement has been detected for vertical SiNWAs due to multiple scattering paths inside the nanowire arrays. On the other hand, inclined nanowires showed a fascinating behavior at the longer wavelength regime, where light gets the longer path to reflect back-forth and ease to reflect back outward at normal incidence. Moreover, for [100] SiNWAs, transverse electric (TE) field component demonstrates the strong polarization insensitive properties at the expense of transverse magnetic (TM) field component with a minimum reflectance of < 2% up to 1200 nm. The [100] SiNWAs demonstrates extra-ordinary omnidirectional properties at θB ≥ 58o. Theoretical validation of COMSOL with an effective medium approach reveal the effective dipole coupling and the presence of strong absorption modes for vertical SiNWs at a typical wavelength regime. The highly bound states of the particle tunneling through classical forbidden region shows a strong enhancement in light absorption effect.
关键词： nanocavities,Si nanowires,light coupling effect,omnidirectional,polarization
更新于2025-09-23 15:22:29
-
Unveiling the radiative local density of optical states of a plasmonic nanocavity by STM
摘要： Atomically-sharp tips in close proximity of metal surfaces create plasmonic nanocavities supporting both radiative (bright) and non-radiative (dark) localized surface plasmon modes. Disentangling their respective contributions to the total density of optical states remains a challenge. Electroluminescence due to tunnelling through the tip-substrate gap could allow the identification of the radiative component, but this information is inherently convoluted with that of the electronic structure of the system. In this work, we present a fully experimental procedure to eliminate the electronic-structure factors from the scanning tunnelling microscope luminescence spectra by confronting them with spectroscopic information extracted from elastic current measurements. Comparison against electromagnetic calculations demonstrates that this procedure allows the characterization of the meV shifts experienced by the nanocavity plasmonic modes under atomic-scale gap size changes. Therefore, the method gives access to the frequency-dependent radiative Purcell enhancement that a microscopic light emitter would undergo when placed at such nanocavity.
关键词： scanning tunnelling microscope luminescence,plasmonic nanocavities,local density of optical states,radiative Purcell enhancement
更新于2025-09-23 15:21:01
-
Enhanced magnetic modulation of light polarization exploiting hybridization with multipolar dark plasmons in magnetoplasmonic nanocavities
摘要： Enhancing magneto-optical effects is crucial for reducing the size of key photonic devices based on the non-reciprocal propagation of light and to enable active nanophotonics. Here, we disclose a currently unexplored approach that exploits hybridization with multipolar dark modes in specially designed magnetoplasmonic nanocavities to achieve a large enhancement of the magneto-optically induced modulation of light polarization. The broken geometrical symmetry of the design enables coupling with free-space light and hybridization of the multipolar dark modes of a plasmonic ring nanoresonator with the dipolar localized plasmon resonance of the ferromagnetic disk placed inside the ring. This hybridization results in a low-radiant multipolar Fano resonance that drives a strongly enhanced magneto-optically induced localized plasmon. The large amplification of the magneto-optical response of the nanocavity is the result of the large magneto-optically induced change in light polarization produced by the strongly enhanced radiant magneto-optical dipole, which is achieved by avoiding the simultaneous enhancement of re-emitted light with incident polarization by the multipolar Fano resonance. The partial compensation of the magneto-optically induced polarization change caused by the large re-emission of light with the original polarization is a critical limitation of the magnetoplasmonic designs explored thus far and that is overcome by the approach proposed here.
关键词： nanophotonics,magnetoplasmonic nanocavities,magneto-optical effects,light polarization modulation,multipolar dark modes
更新于2025-09-23 15:21:01
-
Strong coupling of carbon quantum dots in plasmonic nanocavities
摘要： Strong coupling of carbon quantum dots in plasmonic nanocavities
关键词： carbon quantum dots,strong coupling,plasmonic nanocavities
更新于2025-09-23 15:21:01
-
High Circular Polarized Nanolaser with Chiral Gammadion Metal Cavity
摘要： We demonstrate a circularly polarized laser with the metal-gallium-nitride gammadion nanocavities. The ultraviolet lasing signal was observed with the high circular dichroism at room temperature under pulsed optical pump conditions. Without external magnetism which breaks the time-reversal symmetry to favor optical transitions of a chosen handedness, the coherent outputs of these chiral nanolasers show a dissymmetry factor as high as 1.1. The small footprint of these lasers are advantageous for applications related to circularly polarized photons in future integrated systems, in contrast to the bulky setup of linearly-polarized lasers and quarter-wave plates.
关键词： ultraviolet lasing,gammadion nanocavities,circular dichroism,chiral nanolasers,circularly polarized laser
更新于2025-09-23 15:21:01
-
Self-hybridized exciton-polaritons in multilayers of transition metal dichalcogenides for efficient light absorption
摘要： Transition metal dichalcogenides (TMDCs) have attracted significant attention recently in the context of strong light-matter interaction. To observe strong coupling using these materials, excitons are typically hybridized with resonant photonic modes of stand-alone optical cavities, such as Fabry-Pérot microcavities or plasmonic nanoantennas. Here, we show that thick flakes of layered van der Waals TMDCs can themselves serve as low quality resonators due to their high background permittivity. Optical modes of such “cavities” can in turn hybridize with excitons in the same material. We perform an experimental and theoretical study of such self-hybridization in thick flakes of four common TMDC materials: WS2, WSe2, MoS2, and MoSe2. We observe splitting in reflection and transmission spectra in all four cases and provide angle-resolved dispersion measurements of exciton-polaritons as well as thickness-dependent data. Moreover, we observe significant enhancement and broadening of absorption in thick TMDC multilayers, which can be interpreted in terms of strong light-matter coupling. Remarkably, absorption reaches >50% efficiency across the entire visible spectrum, while simultaneously being weakly dependent on polarization and angle-of-incidence. Our results thus suggest formation of self-hybridized exciton-polaritons in thick TMDC flakes, which in turn may pave the way towards polaritonic and optoelectronic devices in these simple systems.
关键词： transition metal dichalcogenides,exciton-polaritons,strong coupling,nanocavities
更新于2025-09-23 15:21:01
-
Out-of-Plane Nanoscale Reorganization of Lipid Molecules and Nanoparticles Revealed by Plasmonic Spectroscopy
摘要： Lipid bilayers assembled on solid substrates have been extensively studied with single-molecule resolution as the molecules diffuse in 2D, however the out-of-plane motion is typically ignored. Here we present sub-nanometer out-of-plane diffusion of nanoparticles attached to hybrid lipid bilayers (HBLs) assembled on metal surfaces. The nanoscale cavity formed between Au nanoparticle and Au film provides strongly-enhanced optical fields capable of locally probing HBLs assembled in the gaps. This allows us to spectroscopically resolve the nanoparticles assembled on bilayers, near edges, and in membrane defects, showing the strong influence of charged lipid rafts. Nanoparticles sitting on the edges of the HBL are observed to flip onto and off the bilayer, with flip energies of 10 meV showing how thermal energies dynamically modify lipid arrangements around a nanoparticle. We further resolve the movement of individual lipid molecules by doping the HBL with low concentrations of Texas-red (TxR) dye-labeled lipids.
关键词： Purcell factor,Plasmonics,Single-molecule,Nano-assembly,Nanocavities,Lipid bilayers
更新于2025-09-23 15:19:57
-
Sub-100 nm 2D nanopatterning on large scale by ultrafast laser energy regulation
摘要： Coupling ultrafast light to surface nanoreliefs leads to periodic patterns achieving record processing scales down to tens of nanometers. Driven by near-field interactions, the promising potential of the spontaneous pattern formation relies on the scale-up manufacturing one-step process. Here, we report the self-assembly of unconventional arrays of nanocavities of 20 nm diameter with a periodicity down to 60 nm upon ultrafast laser irradiation of a nickel surface. In stark contrast to laser-induced surface ripples, which are stochastic and suffer from a lack of regularity, the 2D patterns present an unprecedented uniformity on extreme scales. The onset of nanocavity arrays ordered in a honeycomb lattice is achieved by overcoming the anisotropic polarization response of the surface by a delayed action of cross-polarized laser pulses. The origin of this self-arrangement is identified as a manifestation of Marangoni convection instability in a nanoscale melt layer, destabilized by the laser-induced rarefaction wave.
关键词： nanopatterning,self-assembly,ultrafast laser,Marangoni convection,nanocavities
更新于2025-09-23 15:19:57
-
Room-Temperature Optical Picocavities below 1 nm <sup>3</sup> Accessing Single-Atom Geometries
摘要： Reproducible con?nement of light on the nanoscale is essential for the ability to observe and control chemical reactions at the single-molecule level. Here we reliably form millions of identical nanocavities and show that the light can be further focused down to the subnanometer scale via the creation of picocavities, single-adatom protrusions with angstrom-level resolution. For the ?rst time, we stabilize and analyze these cavities at room temperatures through high-speed surface-enhanced Raman spectroscopy on speci?cally selected molecular components, collecting and analyzing more than 2 million spectra. Data obtained on these picocavities allows us to deduce structural information on the nanoscale, showing that thiol binding to gold destabilizes the metal surface to optical irradiation. Nitrile moieties are found to stabilize picocavities by 10-fold against their disappearance, typically surviving for >1 s. Such constructs demonstrate the accessibility of single-molecule chemistry under ambient conditions.
关键词： picocavities,surface-enhanced Raman spectroscopy,single-molecule chemistry,optical con?nement,nanocavities
更新于2025-09-23 15:19:57