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- 2019
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- electropolymerization
- polyporphyrin films
- quartz crystal microbalance method
- oxygen electroreduction.
- supercontinuum generation
- Nonlinear
- photonic crystal fiber taper
- Applied Chemistry
- Optoelectronic Information Science and Engineering
- Beijing University of Posts and Telecommunications (BUPT)
- G.A. Krestov Institute of Solution Chemistry of RAS
- University Union Nicola Tesla
- Ivanovo State University of Chemistry and Technology
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Direct Amplification of High Energy Pulsed Laser in Fiber-Single Crystal Fiber with High Average Power
摘要： A laser master oscillator power ampli?er (MOPA) system consisting of a ?ber ampli?er and a two-stage Yb:YAG single crystal ?ber (SCF) is experimentally studied. The nonlinear stimulated Raman scattering (SRS) is avoided by limiting the output power of the ?ber preampli?er to 600 mW. Due to the bene?t from the low nonlinearity and high ampli?cation gain of the SCF, a laser pulse duration of 16.95 ps and a high average power of 41.7 W at a repetition rate of 250 kHz are obtained by using a two-stage polarization controlled double-pass ampli?cation of Yb:YAG SCF, corresponding to an output energy of 166.8 μJ and a peak power of 9.84 MW, respectively. The polarization controlled SCF ampli?cation scheme achieved a gain as high as more than 69 times. During the ampli?cation, the spectra gain narrowing e?ect and the polarization controlled four-pass ampli?cation setup are also studied. The laser spectrum is narrowed from over 10 nm to less than 3 nm, and the pulse width is also compressed to hundreds of femtosecond by dechirping the laser pulse. This compact-sized, cost-e?ective laser source can be used in laser micromachining, or as the seeder source for generating much higher power and energy laser for scienti?c research. For some applications which need femtosecond laser, this laser source can also be compressed to femtosecond regime.
关键词： ytterbium doped fiber amplifier,high-energy ultrashort laser amplification,single crystal fiber
更新于2025-11-28 14:23:57
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[IEEE 2018 Asia Communications and Photonics Conference (ACP) - Hangzhou, China (2018.10.26-2018.10.29)] 2018 Asia Communications and Photonics Conference (ACP) - Visible Coherent Femtosecond Supercontinuum from Air-Suspended-Core Photonic Crystal Fiber
摘要： We report efficient visible supercontinuum (SC) generated from a borosilicate glass photonic crystal fiber, using an 800-nm Ti:sapphire femtosecond laser. Using Michelson interferometer, the SC coherence has been measured to be ~0.8.
关键词： Fiber design and fabrication,Supercontinuum generation,Photonic crystal fibers
更新于2025-11-28 14:23:57
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Investigation on the crack fracture mode and edge quality in laser dicing of glass-anisotropic silicon double-layer wafer
摘要： This work puts forward numerical and experimental investigations on laser dicing of glass-anisotropic single-crystal silicon double-layer wafer using laser induced thermal-crack propagation (LITP). A semiconductor continuous wave laser working at the defocusing mode serves as volumetric heat source for glass layer while as surface heat source for silicon layer. Based on the classical fracture theory, a static seam-type crack is introduced under the circumstance of ABAQUS to simulate the crack fracture modes in glass layer as well as silicon layer with crystal planes of (100), (110) and (111) during laser dicing in different dicing directions. In the experiments, processing parameters are kept the same as the simulations and typical dicing directions obtained from simulations are also used. The surface morphologies of crack edges are measured by the optical microscope and surface profiler. Through the comparison of numerical and experimental results it is discovered that for the specific substrate, the evolution of crack edge qualities in different dicing directions and different layers can be interpreted based on the corresponding stress distribution and stress intensity factor (SIF) ratio explicitly. And most important of all, the anisotropy of silicon layer has significant influence on the fracture mode and edge quality of crack in both layers.
关键词： Crack fracture mode,Laser induced thermal-crack propagation,Glass-anisotropic single-crystal silicon double-layer wafer,Crack edge quality,Static seam-type crack
更新于2025-11-21 11:24:58
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Photo-Sensitive Pb5S2I6 Crystal Incorporated Polydopamine Biointerface Coated on Nanoporous TiO2 as an Efficient Signal-on Photoelectrochemical Bioassay for Ultrasensitive Detection of Cr(VI) ions
摘要： An ultrasensitive Visible light-triggered photoelectrochemical (PEC) sensor was designed based on ideal photoactive lead sulfoiodide (Pb5S2I6) as low band gap crystal, which hydrothermally synthesized rapidly at low temperature (160°C) in hydrochloride acid media followed by its incorporation into polydopamine as reactive photo-biointerface, through a facile in situ electropolymerization method, coated on nanoporous TiO2 grown by anodization on Ti foil. The structure of as-prepared samples and their photoelectrochemical properties were fully characterized. This unique photo-sensitive Pb5S2I6 catalyst-based PEC bioassay was constructed for the detection of low-abundant Cr(VI) ion in real samples. Applying central composite design, individual and mutual interaction effects were evaluated to obtain optimized solution pH, applied potential and radiant light wavelength as operational factors influencing the PEC efficiency for Cr(VI) detection. At optimal condition, the proposed sensor due to effective suppress in electron–hole recombinations showed a very low detection limit of 3.0 nM, over a broad linear concentration range of 0.01 μM-80 μM in addition to high sensitivity versus 1.9 μA/μM Cr(VI). Proposed PEC sensor displayed high selectivity, reproducibility and stability as well as improved excitation conversion efficiency, which make it highly applicable using solar energy. The potential applicability of the designed sensor was evaluated in water, tomato juice and hair color.
关键词： Photoelectrochemical biosensor,Nanoporous TiO2,Cr(VI) ions,Visible light excitation.,Pb5S2I6 crystal
更新于2025-11-21 11:01:37
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Cu(In,Ga)Se2 monograin powders with different Ga content for solar cells
摘要： Monograin layer (MGL) solar cell technology based on CuIn1-xGaxSe2 (CIGSe) monograin powder crystals is a promising approach for the future low-cost production of flexible solar panels. In this study, CuIn1-xGaxSe2 monograin powders (0 ≤ x ≤ 1) were prepared from binary compounds in the liquid phase of potassium iodide as flux material in evacuated quartz ampoules at 720 °C. The crystal structure and the lattice parameters of the CIGSe monograin powder crystals were determined by using X-ray diffraction analysis. A linear decrease of the lattice parameters with increasing Ga concentration was detected. The photoluminescence (PL) spectra of the CIGSe crystals were dominated by the edge emission band that shifted towards higher energies with increasing Ga content. Moreover, additional deep PL band (below 1.0 eV) appeared for Ga contents above x = 0.21 showing higher relative intensity with increasing Ga content. The effective bandgap energy of the CIGSe monograin powder materials ranged from 1.0 eV to 1.68 eV as the [Ga]/([In] + [Ga]) ratio increased from 0 to 1.0. An efficiency of 12.8% (active area) was obtained with the MGL solar cell based on CuIn1-xGaxSe2 monograin powder with Ga content of x = 0.21.
关键词： Cu(In,Ga)Se2,Solar cell,Crystalline powder,Crystal growth
更新于2025-11-21 10:59:37
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Introducing Manganese-Doped Lead Halide Perovskite Quantum Dots: A Simple Synthesis Illustrating Optoelectronic Properties of Semiconductors
摘要： Quantum dots (QDs) are considered useful for demonstrating quantum phenomena in undergraduate laboratories due to their monodisperse size and excellent optical properties. Although doping has an increasingly important role in QD fabrication in the semiconductor field, it has rarely been discussed in the context of the undergraduate laboratory. In this work, a simple synthesis and characterization method for Mn-doped CsPbCl3 QDs for an upper-level undergraduate inorganic chemistry laboratory is reported. The Mn-doped CsPbCl3 system benefits from a simplified synthesis and straightforward characterization. This experiment introduces QD research to students and offers opportunities for instructors to discuss many important concepts in inorganic chemistry, such as energy band theory, particle-in-a-box model, electron paramagnetic resonance, ligand field theory, and nanochemistry.
关键词： Inorganic Chemistry,Crystal Field/Ligand Field Theory,EPR/ESR Spectroscopy,Upper-Division Undergraduate,Hands-On Learning/Manipulatives,Laboratory Instruction,Nanotechnology
更新于2025-11-20 15:33:11
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Band gap engineered zinc oxide nanostructures <i>via</i> a sol–gel synthesis of solvent driven shape-controlled crystal growth
摘要： A reliable sol–gel approach, which combines the formation of ZnO nanocrystals and a solvent driven, low shape-controlled, crystal-growth process to form well-organized ZnO nanostructures at temperature is presented. The sol of ZnO nanocrystals showed shape-controlled crystal growth with respect to the solvent type, resulting in either nanorods, nanoparticles, or nanoslates. The solvothermal process, along with the solvent polarity facilitate the shape-controlled crystal growth process, augmenting the concept of a selective adhesion of solvents onto crystal facets and controlling the final shape of the nanostructures. The XRD traces and XPS spectra support the concept of selective adhesion of solvents onto crystal facets that leads to yield different ZnO morphologies. The shift in optical absorption maxima from 332 nm in initial precursor solution, to 347 nm for ZnO nanocrystals sol, and finally to 375 nm for ZnO nanorods, evidenced the gradual growth and ripening of nanocrystals to dimensional nanostructures. The engineered optical band gaps of ZnO nanostructures are found to be ranged from 3.10 eV to 3.37 eV with respect to the ZnO nanostructures formed in different solvent systems. The theoretical band gaps computed from the experimental XRD spectral traces lie within the range of the optical band gaps obtained from UV-visible spectra of ZnO nanostructures. The spin-casted thin film of ZnO nanorods prepared in DMF exhibits the electrical conductivity of 1.14 × 10?3 S cm?1, which is nearly one order of magnitude higher than the electrical conductivity of ZnO nanoparticles formed in hydroquinone and ZnO sols. The possibility of engineering the band gap and electrical properties of ZnO at nanoscale utilizing an aqueous-based wet chemical synthesis process presented here is simple, versatile, and environmentally friendly, and thus may applicable for making other types of band-gap engineered metal oxide nanostructures with shape-controlled morphologies and optoelectrical properties.
关键词： electrical conductivity,ZnO nanostructures,optical band gap,shape-controlled crystal growth,sol–gel synthesis
更新于2025-11-19 16:56:42
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ZnGa2Se4, a nonlinear material with wide mid infrared transparency and good thermomechanical properties
摘要： During the last decades, mid-infrared (3–12 μm) laser sources using crystals with nonlinear optical properties have attracted a particular attention due to their potential applications in different fields such as optical counter-measures and remote chemical sensing. As transparency of common oxide crystals is limited to about 4 μm, many researches have been focused on chalcopyrite compounds because of their wide transparency in the mid-IR range and their strong nonlinear optical coefficients. There is a need of such crystals able to convert efficiently the near infrared wavelengths from commercially available lasers into wavelengths higher than 5 μm through Optical Parametric Oscillators (OPO) systems. This paper presents a new compound: ZnGa2Se4 (ZGSe). Measurements made on dense polycrystals show a high thermal conductivity value in comparison with other selenides (2.9 W m?1 K?1), a wide transparency from visible to beyond the band III of the mid IR (0.6 μm–17 μm) and a coefficient of thermal expansion inferior to 10?5 K?1. These results are very encouraging and improvements of the growth process are now undertaken to obtain single crystals with the required optical quality.
关键词： Optical materials and properties,ZnGa2Se4,Crystal growth,Thermomechanical properties
更新于2025-11-19 16:56:35
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Synthesis, Crystal Structure, and Photocatalytic Properties of a Zinc(II) Coordination Polymer Based on 3-Hydroxy-2-pyridinecarboxylic Acid
摘要： The zinc(II) compound, [Zn3(HL)6]n (1) (H2L = 3-hydroxypyridine-2-carboxylic acid) was synthesized by a solvothermal reaction of Zn(NO3)2·6H2O and 3-hydroxypyridine-2-carboxylic acid as raw materials. The structure of complex 1 was determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis, Fourier transform infrared spectroscopy, thermogravimetric analysis, as well as powder X-ray diffraction. X-ray structure analysis demonstrates that the complex crystallizes in the monoclinic system, space group P21/n. There are three zinc ions in the asymmetric unit, which are either five-coordinate or six-coordinate. The asymmetric units are further bridged by the carboxylate of the organic ligands, featuring a 2D framework. The solid state diffuse-reflectance UV/Vis spectra reveals that complex 1 has semiconducting nature with the energy bandgap (Eg) estimated to be 3.11 eV. The photocatalytic properties of complex 1 in degradation of organic dyes were further investigated. Results showed that the complex could degrade 54 % of the dye methylene blue solution within 120 min under UV irradiation light and reused for five times without the decline of the photocatalytic activity.
关键词： Crystal structure,Photocatalytic properties,Zinc,3-Hydroxypyridine-2-carboxylic acid,Solvothermal reaction,Coordination polymer
更新于2025-11-19 16:56:35
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Distinguishing the effects of altered morphology and size on visible-light-induced water oxidation activity and photoelectrochemical performance of BaTaO2N crystal structures
摘要： Factors, including crystallinity, morphology, size, preferential orientation, growth, composition, porosity, surface area, etc., can directly influence the optical, charge-separation, charge-transfer and water oxidation and reduction properties of particle-based photocatalysts. Therefore, these factors must be considered when designing high-performance particle-based photocatalysts for solar water splitting. Here, a flux growth method was applied to alter the morphology and size of the Ba5Ta4O15 precursor oxide crystals using BaCl2, KCl, RbCl, CsCl, KCl+BaCl2 and K2SO4 at different solute concentrations, and the impact of nitridation with and without KCl flux was studied. Specifically, the effects of altered morphology and size on the visible-light-induced water oxidation activity and photoelectrochemical performance of the BaTaO2N crystal structures were investigated. Upon nitridation, the samples became porous due to the lattice shrinkage caused by the replacement of 3 O2? with 2 N3? in the anionic network. The BaTaO2N crystal structures obtained by nitridation without KCl flux show higher surface areas than do their counterparts prepared by nitridation with KCl flux because of the formation of porous networks. All samples exhibited a high anodic photocurrent upon nitridation without KCl flux compared with that of the samples obtained by nitridation with KCl flux. The findings demonstrate that it is important to specifically engineer photocatalytic crystals to reach their maximum potential in solar water splitting.
关键词： Water splitting,Visible light,Flux growth,Crystal size,Morphology,BaTaO2N
更新于2025-11-19 16:51:07