A5056653009- Nonlinear Optical Materials Studies
- Quantum Dots Synthesis And Properties
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Nonlinear Optical Materials Research
- Chalcogenide Semiconductor Thin Films
- Advanced Fiber Laser Technologies
- Photonic and Optical Devices
- Porphyrin and Phthalocyanine Chemistry
- Fullerene Chemistry and Applications
- Laser-Matter Interactions and Applications
- Laser-Ablation Synthesis of Nanoparticles
- Diamond and Carbon-based Materials Research
- Nanocluster Synthesis and Applications
- Photorefractive and Nonlinear Optics
- Magnetism in coordination complexes
- Crystal Structures and Properties
- Carbon Nanotubes in Composites
- Graphene research and applications
- Gold and Silver Nanoparticles Synthesis and Applications
- Optical Network Technologies
- Perovskite Materials and Applications
- Phase-change materials and chalcogenides
- Semiconductor Lasers and Optical Devices
- Photonic Crystals and Applications
National University of Singapore
2016-2025
University of California, Berkeley
2025
Nanjing Tech University
2024
Jiangsu University
2000-2024
Fudan University
2012-2024
Beijing University of Technology
2013-2024
Guangdong University of Technology
2024
South China University of Technology
2009-2024
Sandvik (Sweden)
2024
Northeast Forestry University
2024
CuO nanoparticles were successfully prepared by a one-step solid-state reaction under ambient conditions. Three pellet samples with different grain sizes obtained annealing at high temperature. The room temperature Raman spectra of these show that as the size decreases, peaks shift to lower wavenumber and become broader owing effects. dependences on wavelength excitation laser also investigated. Copyright © 1999 John Wiley & Sons, Ltd.
Carbon nanotubes prepared by catalytic (CO) disproportionation were studied using TEM, XRD, UPS, XPS, and optical spectroscopies. In comparison with graphite, the carbon show greater interplanar distance, smaller work function, steeper Fermi edge, negative core-level shift, stronger plasma excitation. Their valence band is basically same as that of lower intensity in binding energy region 2--7 eV. The exhibit a strong limiting effect, superior to both black ${\mathrm{C}}_{60}$.
Abstract: Research on two-dimensional (2D) materials has been explosively increasing in last seventeen years varying subjects including condensed matter physics, electronic engineering, science, and chemistry since the mechanical exfoliation of graphene 2004. Starting from graphene, 2D now have become a big family with numerous members diverse categories. The unique structural features physicochemical properties make them one class most appealing candidates for wide range potential...
The synthesis of gold nanospheres via the reduction AuCl4- salt by sodium citrate has been revisited, with focus on mechanism particle growth. In stark contrast to widely accepted LaMer nucleation-growth model, initially formed nanoclusters about 5 nm diameter self-assemble form an extensive network nanowires. nanowires progressively increases in size, and at same time connected is fragmented into small segments before final spherical particles are formed. We put forward a modified...
In this paper, copper nanoparticles were prepared by the reduction of copper(II) acetate in water and 2-ethoxyethanol using hydrazine under reflux. The synthesized exhibit a distinct absorption peak region 572−582 nm. average size variation from 6.6 to 22.7 nm ethoxyethanol 15.5 30.2 was achieved addition various amounts protective polymer (poly(N-vinylpyrrolidone)). nonlinear optical properties colloids first measured Z-scan technique. χ(3)/α0 values obtained found be magnitude 10-11−10-12...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and Optical Limiting Capability of Cubane-like Mixed Metal Clusters (n-Bu4N)3[MoAg3BrX3S4] (X = Cl I)S. Shi, W. Ji, S. H. Tang, J. P. Lang, X. Q. XinCite this: Am. Chem. Soc. 1994, 116, 8, 3615–3616Publication Date (Print):April 1, 1994Publication History Published online1 May 2002Published inissue 1 April 1994https://pubs.acs.org/doi/10.1021/ja00087a064https://doi.org/10.1021/ja00087a064research-articleACS PublicationsRequest reuse...
High-quality, monodisperse PbS−Au1, PbS−Au4, and PbS−Aun nanostructures have been synthesized via a facile convenient solution chemistry approach. HRTEM images of these showed good selectivity gold deposition on the semiconductor in several spatially correlated directions. The formation regular can be explained by difference polarity crystal facets that led to selective growth metal surface. Owing their narrow size distribution intrinsic high-symmetry, resulting PbS−Au4 heterogeneous could...
We report a systematic investigation of both three-photon absorption (3PA)spectra and wavelength dispersions Kerr-type nonlinear refraction in wide-gap semiconductors. The Z-scan measurements are recorded for ZnO ZnS with femtosecond laser pulses. While the Kerr nonlinearity agreement two-band model, dependences 3PA found to be given by (3Ephoton/Eg-1)5/2(3Ephoton/Eg)-9. also evaluate higher-order optical effects including fifth-order instantaneous associated virtual transitions, effectively...
A hybrid system of ZnO nanoparticles on multiwalled carbon nanotubes (MWNTs) is fabricated by simply heating Zn-coated MWNTs a hot plate in air. Ultrafast optical switching and three-photon adsorption are observed from this system, the absorption coefficient can be readily adjusted changing Zn-coating thickness. These results provide opportunities for cost-effectively integrating with functional oxide future nanodevices.
Saturable and reverse saturable absorption at longitudinal surface plasmon resonance (SPR) in gold nanorods (Au NRs) have been observed using Z-scan transient techniques with femtosecond laser pulses. At lower excitation irradiances, the wavelength dispersion of has determined near mode SPR a recovery time to be few ten picoseconds on resonance. With higher occurs becomes dominant. The underlying mechanisms are discussed. Such reversible makes Au NRs an ideal candidate for optical limiting...
Optical limiting effects in multiwalled carbon nanotubes have been observed the visible and infrared spectral regions with nanosecond laser pulses. The investigated include those suspended distilled water embedded polymethyl methacrylate films. Among all samples measured, performance of nanotube suspension is best threshold determined to be ∼1, 5, 13 J/cm2 at 532, 700, 1064 nm, respectively. possible mechanism for discussed.
We present a quantum perturbation theory on two-photon absorption (2PA) in monolayer and bilayer graphene which is Bernal-stacked. The shows that 2PA significantly greater than the visible infrared spectrum (up to 3 μm) with resonant coefficient of up ∼0.2 cm/W located at half bandgap energy, γ1 = 0.4 eV. In terahertz region, exhibits light frequency dependence ω–3 graphene, while it proportional ω–4 for all photon energies. Within same order magnitude, agreement our Z-scan measurements...
TiO(2) nanotubes can reproducibly store up to approximately 2 wt % H(2) at room temperature and 6 MPa. However, only about 75% of this stored hydrogen be released when the pressure is lowered ambient conditions, suggesting that both physisorption chemisorption are responsible for uptake. FTIR spectroscopy, temperature-programmed desorption (TPD), pressure-composition (P-C) isotherms suggest physisorbed reversibly upon reduction. Approximately 13% weakly chemisorbed 70 degrees C as H(2), 12%...
Highly nitrogen-doped carbon nanotube (${\mathrm{CN}}_{x}\mathrm{NT}$, $x=12\phantom{\rule{0.3em}{0ex}}\mathrm{at.}\phantom{\rule{0.2em}{0ex}}%$) was synthesized by the pyrolysis of acetonitrile on Co-Mo catalysts. The electronic structures and chemical bondings ${\mathrm{CN}}_{x}\mathrm{NT}$ were studied using various spectroscopic techniques: Raman, photoelectron x-ray absorption spectroscopies. ultrafast pump-probe measurements exhibited a larger third-order susceptibility...
Hybrid composites of CdS nanoparticles embedded in sulfonated polystyrene (PS) matrixes have been prepared and characterized. The −SO3- groups acted as the coordination sites for cadmium ion aggregations nanosized particles were successfully grown situ at these with release S2- ions from thioacetamide. density size found to be a function sulfonate content PS concentration Cd2+ feed used. Ionic clusterings within polymer matrix occurred 9.9 mol % has provided confined medium particle growth...
Multiphoton upconversion is a process where two or more photons are absorbed simultaneously to excite an electron excited state and, subsequently, the relaxation of gives rise emission photon with frequency greater than those photons. Materials possessing such property attracted attention due applications in biological imaging, photodynamic therapy, three-dimensional optical data storage, frequency-upconverted lasing and power limiting. Here we report four-photon metal-organic frameworks...
A negative value for the nonlinear refraction in graphene is experimentally observed and unambiguously verified by performing a theoretical analysis arising from conductivity of monolayer. The optical properties multi-layer are studied employing Z-scan technique. measurements carried out at 1150, 1550, 1900 2400 nm with 100-femtosecond laser source. Under illumination exhibits transmittance increase due to saturable absorption, followed limiting two-photon absorption. saturation irradiance...
Highly sensitive, multicomponent broadband photodetector devices are made from PbSe/graphene/TiO2. TiO2 and PbSe nanoparticles act as light harvesting photoactive materials the UV to IR regions of electromagnetic spectrum, while graphene acts a charge collector for both photogenerated holes electrons under an applied electric field. Detailed facts importance specialist readers published ”Supporting Information”. Such documents peer-reviewed, but not copy-edited or typeset. They available...
We report strong broad-band optical-limiting properties of oleylamine-capped gold nanoparticles in solution for both femtosecond and nanosecond laser pulses. The effects were characterized by using fluence-dependent transmittance measurements with 7 ns pulses at 532 1064 nm, the a z-scan technique 300 fs 780 nm. found to show nm These displayed exceptional thresholds lower than that carbon nanotube suspension, benchmark optical limiter. Input-fluence- angle-dependent scattering suggested...
Single-source precursor, [(Ph3P)CuIn(SC{O}Ph)4] (1), and dual-source precursors, [Cu(SC{O}Ph)] (2) [In(bipy)(SC{O}Ph)3] (3), have been used to obtain the monodispersed wurtzite (hexagonal) zincblende (also called sphalerite, cubic) phases of copper indium sulfide nanocrystals (CIS NCs). The NCs characterized by X-ray powder diffraction patterns, transmission electron microscopy, selected area diffraction, energy-dispersive analysis. It is shown that relative ratios surfactants influence on...