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oe1(光电查) - 科学论文

324 条数据
?? 中文(中国)
  • Synthesis of novel azo group substituted polymeric phthalocyanine for amperometric sensing of nitrite

    摘要: The novel tetraazo-bridged cobalt phthalocyanine polymer [poly(TazoCoPc)] was synthesized by oxy-bridge to extend the conjugation effect on the phthalocyanine molecule. Firstly, the ligand [phenyl-1,4-bisdiazenyl naphthalene-1-oxy] benzene 1,2-dicarbonitrile was prepared and it was characterized. Then, the polymeric phthalocyanine was prepared and characterized by elemental analysis, UV-Vis, FTIR, TGA, XRD and electrochemistry. Polymeric phthalocyanine and carbon nanoparticles (CNP) were mixed and used for modifying the glassy carbon electrode to fabricate the electrochemical voltametric and amperometric nitrite sensor. Composite of phthalocyanine polymer and CNP exhibits enhanced electrocatalytic behaviour for the oxidation of nitrite compared to pure polymeric phthalocyanine. The fabricated amperometric sensor exhibits excellent analytical performance for nitrite detection in the concentration range of 20 nM to 1 μM with a detection limit of 6 nM (S/N = 3) and a sensitivity of 0.137 mA/μM. The modified composite electrode is highly selective and it didn’t show any interference effect even in presence of excess interfering ions such as Mg2+, SO4 2-, K+, CO3 2-, NO3 -.

    关键词: phthalocyanine polymer,nitrite sensor,amperometry,carbon nanoparticle,voltametry

    更新于2025-09-23 15:21:01

  • Using adaptive neuro-fuzzy and genetic algorithm for simultaneously estimating the dye and AgNP concentrations of treated silk fabrics with nanosilver

    摘要: Purpose – Arti?cial intelligence (AI) methods, such as genetic algorithm (GA) and adaptive neuro-fuzzy inference system (ANFIS), are capable of providing superior solutions for the simulation and the modeling of complex problems. The purpose of this study is to estimate the dye and the silver nanoparticle (AgNP) concentrations of silver nanoparticle-treated silk fabrics by the aforementioned methods. Design/methodology/approach – In this study, the color and the antimicrobial properties of silver nanoparticle-treated silk fabrics were matched by using the GA technique based on spectrophotometric color matching. The ANFIS method was also used; this method is based on the grid partitioning algorithm across four different methods. The ?rst and second methods are provided for dye concentration prediction, and the third and the fourth methods are given for AgNP concentration prediction. Findings – The mean of absolute error and root mean square (RMS) of the best dye concentration prediction by the ANFIS method based on the second method are 0.087 and 0.103, respectively. In addition, the mean of the absolute error and the RMS of the best results for AgNP concentration prediction by the ANFIS method by using the third method is 0.002 and 0.003, respectively. The obtained results indicate that the performance of the ANFIS method is better than the GA method. Originality value – The simultaneous prediction of the color and the antimicrobial properties of silver nanoparticle-treated silk fabrics was performed by using the GA and the ANFIS. The suggested method led to acceptable accuracy for color and antibacterial matching.

    关键词: Prediction,Silver nanoparticle,Genetic algorithm,Neuro-fuzzy,Dye

    更新于2025-09-23 15:21:01

  • The use of Highly Ionized Pulsed Plasmas for the Synthesis of Advanced Thin Films and Nanoparticles

    摘要: Pulsed plasma processes open up the possibility of using very high plasma densities and modulated deposition in the synthesis of thin films and nanoparticles. The high plasma densities lead to a high degree of ionization of the source material, which creates new possibilities for surface engineering. Ions can, in contrast to atoms, be easily controlled with regard to their energy and direction, which is beneficial for thin film growth. Furthermore, ions can also increase the trapping probability of material on nanoparticles growing in the gas phase. The pulsed sputter ejection of source material also has other consequences: the material in the plasma and the material arrival on the growth surface will fluctuate strongly resulting in high level of supersaturation during pulse-on time. In this paper, an overview of the generation and properties of highly ionized pulsed plasmas is given. In addition, the use and importance of these types of discharges in the fields of thin-film and nanoparticle growth are also summarized.

    关键词: HiPIMS,HPPMS,sputtering,IPVD,thin films,nanoparticle synthesis

    更新于2025-09-23 15:21:01

  • PRECISE FINITE DIFFERENCE ANALYSIS OF LORENTZ FORCE ACTING ON METAL NANOPARTICLE IRRADIATED WITH LIGHT

    摘要: A ?nite di?erence method in the frequency domain is evaluated to clarify characteristics of the Lorentz force exerted on a metal nanoscale particle by light irradiation. Numerical results are compared with exact values obtained from Mie theory to show that applying a smoothing algorithm to the surface of a nanoparticle increases the accuracy of the simulation. Analysis of the Lorentz force exerted between two spheres aligned closely indicates that strong forces cause the spheres to attract each other at the plasmon resonant frequency. It was also noticed that application of the smoothing algorithm was indispensable in order to achieve the above result.

    关键词: plasmon resonance,finite difference method,Lorentz force,light irradiation,metal nanoparticle,Mie theory

    更新于2025-09-23 15:21:01

  • Formation of Gold Nanoparticles in a Free-Standing Ionic Liquid Triggered by Heat and Electron Irradiation

    摘要: Ionic liquids (ILs) feature negligibly low vapor pressures and can thus be freely introduced into the high vacuum of a transmission electron microscope. With this extraordinary property, the ILs offer a powerful tool for in situ transmission electron microscopy (TEM) in window-free liquid media at very high resolution. In this work, we use the IL 1-butyl-3-methyl imidazolium chloride in order to study nucleation and growth of gold nanoparticles (NPs) in free-standing liquid droplets by scanning TEM (STEM). The results confirm that the used IL allows for generating Au NP in situ, triggered by electron irradiation and heat. Firstly, the isotropic growth of small, spherical Au NPs was initiated and monitored whereas different growth mechanisms were observed, i.e. growth by monomer attachment, growth through particle coalescence and possible Ostwald ripening events. After the initial growth phase, a second, anisotropic growth process was induced by a moderate temperature increase and continued electron irradiation. As a result, larger, faceted crystals such as tetrahedra, octahedra or decahedra were formed. As all these polymorphs are terminated by {111}-facets, the IL might not only act as liquid medium but in addition as a surfactant which preferentially attaches on the {100}-facets.

    关键词: gold,in situ,TEM,heat,nanoparticle growth,ionic liquid

    更新于2025-09-23 15:21:01

  • Modulation of localized surface plasmon resonances of a silver nanoparticle array upon the presence of MoS2 coatings or underlying thin films

    摘要: There has been recently a growing interest in studying light-matter coupling using supported metallic nanostructures arranged into periodic arrays. The influence on the layer thickness of two-dimensional materials such as molybdenum disulfide MoS2 on the plasmonic behaviour of these arrays has become of great relevance due to the favorable bonding between S (sulfide atom) and metal atoms such as gold and silver as well as the variation of optical transition of MoS2 depending on the atomic thickness of the film. In this work, we have numerically studied the change in absorption spectra of an ordered array of silver nanoparticles AgNPs when attached to glass as well as to glass coated with different layers of MoS2. This arrangement was compared to an AgNPs attached to glass and post coated with MoS2 films of increasing thickness. It was shown that an overcoating of four MoS2 layers results in an increased plasmonic sensitivity compared to uncoated glass/AgNPs interface. Replacing the glass substrate by glass coated with MoS2 of different thickness and with added AgNPs shows a significant to the red shift with increasing MoS2 layers. This band is due to strong excitation-plasmon coupling of the silver lattice with MoS2 layers. Important is the fact that the electrical field is strongly enhanced beneath the MoS2/AgNPs barrier. One also observes a significant enhancement of the sensitivity. Hence, the design of more sensitive AgNPs/MoS2 based-plasmonic biosensors could be reached. Indeed, we show that AgNPs coating with few layers of MoS2 leads to approximately a 210.26% higher sensitivity.

    关键词: Sensitivity,MoS2,Silver nanoparticle array,BioSensors,Localized surface plasmon resonance

    更新于2025-09-23 15:21:01

  • [IEEE 2018 15th IEEE India Council International Conference (INDICON) - Coimbatore, India (2018.12.16-2018.12.18)] 2018 15th IEEE India Council International Conference (INDICON) - Influence of the Compositional Variation of Zn <sub/>x</sub> Cd <sub/>1a??x</sub> S (0 a?¤ x a?¤ 0.45) Buffer on Efficiency of Cu <sub/>2</sub> ZnSnSe <sub/>4</sub> Solar Cell: A Simulation

    摘要: This paper investigates the manufacturability-aware process of p-n junction formation for photovoltaic cells involving with Si nanoparticle layer. The furnace-based dopant diffusion process of forming a p-n junction consumes a substantial amount of energy. In addition, repetitive production steps prevent the possibility of Si ink-based cells integrating onto ?exible substrates. This research examined the local heating dopant diffusion process by using a ?ber laser at a wavelength of 1064 nm. The infrared beam is delivered onto the wafer stack with a nanoparticle carbon layer and n-type Si ink layer on p-type Si substrates. The nanoparticle carbon ?lm absorbs infrared beam energy and converts photon energy as a thermal source to diffuse the n-type dopant in Si ink into the p-type Si wafer. The Si ink in this paper contains a mixture of Si nanoparticles and an n-type spin-on dopant solution. The TEM results show that Si nanoparticles are uniformly dispersed on the Si wafer surface. This research investigated sheet resistance as a function of laser parameters, including laser power, scanning speed, and pulse frequency for the samples coated with Si ink. Secondary ion mass spectroscopy measurements indicate the presence of an n-type dopant in p-type substrates, with an approximate diffusion depth of 100 nm. The results indicate that the proposed infrared laser treatment technique is promising for the formation of p-n junctions with Si ink-based photovoltaic cells.

    关键词: silicon ink,spin-on dopant (SOD),silicon nanoparticle,carbon nanoparticle,?ber laser,Flexible photovoltaic cell,pn junction

    更新于2025-09-23 15:19:57

  • Enhanced Broadband and Harmonic Upconversion from Coupled Semiconductor and Metal Nanoparticle Films

    摘要: The enhancement of the nonlinear optical properties of hybrid nanoparticle ?lms by coupling between metallic and plasmonic semiconducting nanoparticles is shown. A heterostructure comprising CuS and Au nanoparticle ?lms separated by a thin layer of insulating ligands enhanced the yield of second-harmonic light by a factor of 3.3 compared with the sum of the constituent nanoparticles on their own. Heterostructures were fabricated with scalable solution-processing techniques that can create devices of arbitrary geometry. In addition to harmonic generation, the multiple-photon photoluminescence response of Au, CuS, and heterostructured ?lms is also explored.

    关键词: plasmon,heterostructure,copper sul?de nanoparticle,second-harmonic generation,gold nanoparticle,multiphoton photoluminescence,nonlinear optical material

    更新于2025-09-23 15:19:57

  • Light-Induced Coalescence of Plasmonic Dimers and Clusters

    摘要: The properties of nanoplasmonic structures depend strongly on their geometry, creating the need for high-precision control and characterization. Here, by exploiting the low activation energy of gold atoms on nanoparticle surfaces, we show how laser irradiation re-shapes nanoparticle dimers. Time-course dark-field micro-spectroscopy allows this process to be studied in detail for individual nanostructures. Three regimes are identified: facet growth, formation of a conductive bridge between particles, and bridge growth. Electromagnetic simulations confirm the growth dynamics and allow measurement of bridge diameter, found to be highly reproducible and also self-limiting. Correlations in spectral resonances for the initial and final states give insights into the energy barriers for bridge growth. Dark-field microscopy shows that coalescence of multiple gaps in nanoparticle clusters can be digitally triggered, with each gap closing after discrete increases in irradiation power. Such control is important for light-induced nanowire formation or trimming of electronic and optoelectronic devices.

    关键词: nanoparticle coalescence,gold nanoparticles,optical spectroscopy,plasmonics,sintering,nanoparticle dimers

    更新于2025-09-23 15:19:57

  • Functionalized carbon dots on TiO2 for perovskite photovoltaics and stable photoanodes for water splitting

    摘要: Various types of fluorescent carbon nanoparticles, often called carbon dots (CDs), are synthesized by different polycondensation methods: microwave irradiation, hydrothermal conditions or solution chemistry at ambient temperature with subsequent chemical functionalization. The CDs are deposited on TiO2 films to be probed as electron transport layers in perovskite photovoltaics and the anode for photoelectrochemical water splitting. Nitrogen CDs, which do not contain oxygen, lead to an increase of around 50 mV in the open circuit voltage of perovskite solar cells. All the CD types produce an improved photocurrent in water splitting, particularly CDs that are functionalized with thiol groups and butyl chains. It is demonstrated that the modified electrode is stable under continuous operation. Other electrochemical characteristics of the electrode, such as the voltammogram shape, onset potentials and open circuit potentials, remain nearly unchanged upon the deposition of CDs. Only the incident photon to current conversion efficiency improves clearly, extending the absorption range by around 20 nm towards longer wavelengths. This study provides new data about mechanisms and electrode arrangements for improving the performance of n-type semiconductors in photovoltaic cells and photoelectrochemical hydrogen production.

    关键词: Sustainability,Titanium dioxide,Renewable hydrogen,Carbon nanoparticle,Solar energy

    更新于2025-09-23 15:19:57