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Surface Plasmon Resonance in a metallic nanoparticle embedded in a semiconductor matrix: exciton-plasmon coupling
摘要： We consider the effect of electromagnetic coupling between localized surface plasmons in a metallic nanoparticle (NP) and excitons or weakly interacting electron-hole pairs in a semiconductor matrix where the NP is embedded. An expression is derived for the NP polarizability renormalized by this coupling and two possible situations are analyzed, both compatable with the conditions for Fano-type resonances: (i) a narrow bound exciton transition overlapping with the NP surface plasmon resonance (SPR), and (ii) SPR overlapping with a parabolic absorption band due to electron-hole transitions in the semiconductor. The absorption band lineshape is strongly non-Lorentzian in both cases and similar to the typical Fano spectrum in the case (i). However, it looks differently in the situation (ii) that takes place for gold NPs embedded in a CuO film and the use of the renormalized polarizability derived in this work permits to obtain a very good fit to the experimentally measured LSPR lineshape.
关键词： Localized surface plasmon,Nanoparticle,Semiconductor,Dielectric function,Composite,Fano resonance,Exciton
更新于2025-09-04 15:30:14
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Optimization of CdS/TiO2 Nanotube-Array Composite Photocatalysts Prepared by Electrodeposition
摘要： Titania nanotube arrays were prepared by titanium anodizing, then CdS/TiO2 nanotube arrays composite photocatalysts were prepared by an AC electrodeposition method for different times. The morphology and crystal structure of the CdS/TiO2 composite photocatalysts were characterized by SEM and XRD. The photoelectrochemical properties of the composites were investigated by means of UV-visible absorption spectra and photocurrent measurements. The photocatalytic activity was evaluated by the degradation of methyl orange under UV-visible light irradiation. The results show that there is an optimum deposited time for the highest photocatalytical activity of the CdS/TiO2 composite photocatalysts under UV-visible light irradiation and the optimum deposited time is determined to 3 min.
关键词： Electrodeposition,Nanotube array,Composite photocatalyst,Methyl orange,CdS/TiO2
更新于2025-09-04 15:30:14
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Light Emitting Diodes Based on Inorganic Composite Halide Perovskites
摘要： CsPbBr3 is a promising type of light-emitting halide perovskite with inorganic composition and desirable thermal stability. The luminescence efficiency of pristine CsPbBr3 thin films, however, appears to be limited. In this work, light emitting diodes based on CsPbBr3|Cs4PbBr6 composites are demonstrated. Both quantum efficiency and emission brightness are improved significantly compared with similar devices constructed using pure CsPbBr3. The high brightness can be attributed to the enhanced radiative recombination from CsPbBr3 crystallites confined in the Cs4PbBr6 host matrix. The unfavorable charge transport property of Cs4PbBr6 can be circumvented by optimizing the ratio between the host and the guest components and the total thickness of the composite thin films. The inorganic composition of the emitting layer also leads to improved device stability under the condition of continuous operation.
关键词： stability,conductivity,composite perovskite,light emitting diode,Cs4PbBr6
更新于2025-09-04 15:30:14
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Solution-processed flexible non-volatile resistive switching device based on poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(benzo[2,1,3]thiadiazol-4, 8-diyl)]: polyvinylpyrrolidone composite and its conduction mechanism
摘要： Recently, solution-processed resistive switches for wearable electronics have got tremendous attention and are required for different applications due to their easy process and fabrication. Hence, this paper proposes the solution-processed resistive switching memory device based on two polymers, poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(benzo[2,1,3]thiadiazol-4, 8-diyl)] (F8BT) and polyvinylpyrrolidone (PVP) composite, which is fabricated on a flexible indium–tin–oxide (ITO)-coated polyethylene terephthalate (PET) substrate through spin coating technology. The fabricated device demonstrates a perfect non-volatile bipolar resistive switching through small operating voltage sweeping of ± 1.5 V, and its high-resistance state (HRS) and low-resistance state (LRS) are 92678.89 ? and 337.85 ?, respectively. To verify the non-volatility and long-term stability, the device is checked for more than 700 endurance cycles. During these cycles, the variations of HRS and LRS are 48 ? and 37.35 ?, respectively. The retention time is checked for more than 60 days, and the ROFF/RON ratio is 274.31. The bendability is carried out up to bending diameters < 10 mm, and FESEM is used for the morphological characteristics of the device. Conduction mechanism of the proposed device is supported by space charge-limited conduction (SCLC) which is explained by the log–log I–V slope-fitting curve. The results insure that the F8BT:PVP composite-based resistive switching device is to be a potential candidate for the future flexible and low-power non-volatile resistive switching memory device.
关键词： Resistive switching,Composite,F8BT,Solution-processed,Flexible,Non-volatile,PVP,Conduction mechanism
更新于2025-09-04 15:30:14
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Facile Synthesis of Luminescent CdSeS/Polystyrene Composite Microspheres by Use of Butan-1-ol
摘要： Quantum dot/polymer composites combine the desirable optical properties of quantum dots with the surface properties of colloidal polymer microspheres. The use of the medium polarity solvent, butan-1-ol, facilitates dispersion polymerization of 0.7 μm carboxylated polystyrene/CdSeS composites–the first example of polymer composites with ternary alloyed quantum dots synthesized by dispersion polymerization.
关键词： Polystyrene,Quantum Dot,Dispersion Polymerization,Composite
更新于2025-09-04 15:30:14
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Fracture behaviors of a piezoelectric-piezomagnetic sandwich structure under electromechanical loads: plane problem
摘要： The fracture behaviors of a piezoelectric-piezomagnetic sandwich structure with an eccentric internal crack subjected to two kinds of in-plane electromechanical loads have been studied in this paper. A singular integral equation with Cauchy kernel is obtained by means of Fourier transform and further solved by using Gauss-Chebyshev technique. Then the stress intensity factors are obtained and some numerical results are presented to show the e?ects of the material properties, structure geometries, electromechanical loads and the crack location on the stress intensity factors. The conclusions of the present paper may be useful for the design and fracture prediction of layered piezoelectric-piezomagnetic structures.
关键词： sandwich structure,stress intensity factor,plane strain problem,integral transformation,Piezoelectric-Piezomagnetic composite
更新于2025-09-04 15:30:14
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Evaluation of Exfoliated Graphite to Graphene in Polyamide 66 Using Novel High Shear Elongational Flow
摘要： Graphene has been publicized as the game changing material of this millennium. To this day, scalable production leading to exceptional material properties has been difficult to attain. Most methods require harsh chemicals, which result in destroying the graphene surface. A method was developed, exploiting high speed elongational flow in a novel designed batch mixer; creating a distribution of pristine few to many layer graphene flakes. The method focuses on exfoliating in a molten polyamide 66 (PA66) matrix, creating a graphene reinforced polymer matrix composite (G-PMC). The process revealed that high speed elongational flow was able to create few layer graphene. Graphite exfoliation was found driven in part by diffusion, leading to intercalation of PA66 in graphite. The intercalated structure lead to increases in the hydrogen bonding domain, creating anisotropic crystal domains. The thermal stability of the G-PMC was found to be dependent to the degree of exfoliation, PA66 crystal structure and composite morphology. The aim of this research is to characterize uniquely produced graphene containing polymer matrix composites using a newly created elongational flow field. Using elongational flow, graphite will be directly exfoliated into graphene within a molten polymer.
关键词： polyamide 66,elongational flow,graphene polymer matrix composite,hydrogen bond,graphene
更新于2025-09-04 15:30:14
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Calcination Effects and Photocatalytic Activity of Porous SiO2-TiO2 Material
摘要： A porous SiO2-TiO2 photocatalyst was prepared through co-sol-gel method using PEG1000 template for photocatalytic degradation of methyl orange. Photocatalytic degradation was conducted after adsorption equilibrium to identify the contribution of both adsorption and photocatalytic degradation. The optimum calcination condition for the porous SiO2-TiO2 is 500 °C for 3 h. The adsorption of methyl orange on the photocatalyst has no apparent change in the whole temperature range. Nearly 96.5 % of the initial methyl orange is removed in 100 min under UV light irradiation with the existence of the porous SiO2-TiO2. Methyl orange degradation follows the first order kinetics equation. The azo and benzene structure are degraded into small molecules during photocatalytic oxidation process.
关键词： Photocatalysis,Composite,SiO2,TiO2
更新于2025-09-04 15:30:14
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ANALYSIS OF SCATTERING FROM COMPOSITE CONDUCTOR AND DIELECTRIC OBJECTS USING SINGLE INTEGRAL EQUATION METHOD AND MLFMA BASED ON JMCFIE
摘要： A highly e?cient hybrid method of single integral equation (SIE) and electric/magnetic current combined ?eld integral equation (JMCFIE) is presented, named as SJMCFIE, for analysing scattering from composite conductor and dielectric objects, in which, SIE can reduce one half unknowns in dielectric region. The resultant matrix equation of SJMCFIE can be represented in the iteration form, which makes the computation complexity reduced further, and coupling mechanism of composite model becomes more explicit. For accelerating matrix-vector multiplications (MVMs), Multilevel Fast Multipole Algorithm (MLFMA) is employed to combine SJMCFIE to formulate SJMCFIE-MLFMA at last, which is the extension of SIE-MLFMA in the proposed reference. Finally, some examples verify the new hybrid method on accuracy, memory storage, computation e?ciency compared to SIE-MLFMA and JMCFIE-MLFMA. Besides, SJMCFIE-MLFMA can also be used to analyse the complete coated model’s scattering.
关键词： composite conductor and dielectric objects,Multilevel Fast Multipole Algorithm,electric/magnetic current combined ?eld integral equation,single integral equation,scattering
更新于2025-09-04 15:30:14
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Direct Synthesis of Gold Nanoparticle‐Over‐Nanosheet for Sensitive SERS Detection
摘要： A simple ethanol sol-based method for the synthesis of gold nanosheets (AuNSs) and gold nanoparticle-over-nanosheet (AuNP/NS) is developed. Gold nanoparticles (AuNPs) with average sizes of ≈8 nm are grown in situ on the surface of the AuNS, which forms a NP/NS structure that obtains strong, significantly improved, surface-enhanced Raman spectroscopy activity with the magnitude ≈2 and ≈6 orders higher than the simplex AuNP and AuNS, respectively. This performance is mainly attributed to uniform AuNPs that are closely packed over AuNS and coupled with NP–NS and NP–NP interactions. The NP–NS–GP (the gap between NP–NS) is narrower than NP–NP–GP in which much stronger and steadier plasmon resonance is obtained that can significantly enhance the Raman signal. The results show that single-crystalline AuNS is an ideal substrate, which can be further coated with other metallic NPs to form a new flexible, high-activity and AuNS-based nanocomposite for a wide variety of applications.
关键词： gold nanoparticle-over-nanosheet (AuNP/NS) composite,2D gold nanosheet (AuNS),surface-enhanced Raman spectroscopy (SERS)
更新于2025-09-04 15:30:14