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Optimized thermochromic properties of VO2/CoFe2O4 nanocomposite films via band gap engineering
摘要： VO2/CoFe2O4 nanoparticle composites were synthesized by hydrothermal method combined with annealing treatment. The nanocomposites consist of quasi-spherical nanoparticles with an average size of about 70 nm. The thermochromic properties of the nanocomposite films can be modulated by changing film thickness and the content of CoFe2O4 in the nanocomposites. The band gap of the VO2/CoFe2O4 nanocomposites increases with increasing CoFe2O4 additive content. The introduction of CoFe2O4 into VO2 matrix can not only lower the phase transition temperature, but also optimize the luminous transmittance and solar modulation ability of the VO2/CoFe2O4 nanocomposites as well. Our findings demonstrate a promising avenue in constructing VO2-based smart films with excellent thermochromic performance.
关键词： Solar modulation ability,VO2/CoFe2O4 nanocomposite,Luminous transmittance,Phase transition temperature
更新于2025-09-23 15:21:21
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Surface-Initiated Metal-Free Photoinduced ATRP of 4-Vinylpyridine from SiO2 via Visible Light Photocatalyst for Self-healing Hydrogels
摘要： Robust and self-healable nanocomposite hydrogels was realized by the encapsulation of components of photoinduced electron transfer-atom transfer radical polymerization (PET-ATRP) into the surface-modified silica nanoparticles (SiO2). The prepared SiO2@P4VP was in the form of self-healing nanocomposite hydrogels, where 4-Vinylpyridine (4VP) was polymerized through PET-ATRP with organic photocatalyst Rhodamine B. The modified nanoparticles were characterized by X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR). The nanocomposite hydrogels can be healed rapidly and autonomously without any stimulation at ambient temperature. Specifically, the nanocomposite hydrogels has a tensile strength of about 2.90 MPa, which recovered to 77.0% after 12 hours, and an elongation at break of about 730 %. These self-healing hydrogels with cheap raw material, possess better strength and self-healing performance, will have broad prospects.
关键词： Self-Healing Hydrogels,Visible Light,Metal-Free Photoinduced ATRP,Nanocomposite Hydrogels
更新于2025-09-23 15:21:21
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Graphene oxide coated flower-shaped ZnO nanorods: Optoelectronic properties
摘要： In this paper, the influence of graphene oxide coating on optical and photoluminescence properties of zinc oxide nanorods (ZnO NRs) has been investigated. ZnO NRs were prepared using a hydrothermal route (from zinc nitrate hexahydrate and hexamethylenetetramine), graphene oxide (GO) was fabricated by Hummer's method, while for synthesis of ZnO nanorods:graphene oxide nanocomposite (ZnO NRs:GO) on Si (100) substrate, a facile technique (drop coating) was proposed. The structural, morphological, optical and luminescence properties of the films were investigated using X-ray diffraction (XRD) technique, scanning electron microscopy (SEM), together with Fourier transform infrared (FT-IR), Raman, ultraviolet- visible- near-infrared (UV/VIS/NIR) and photoluminescence (PL) spectroscopies. As revealed by XRD analysis, composites display a hexagonal wurtzite type structure with a (101) preferred grain orientation. The average crystallite sizes decrease from 45 to 40 nm after GO coating. The SEM study confirms successful coating of GO layers on flower-like ZnO nanostructures. The FTIR and Raman analyses validated the hybridization of nanocomposite and the strong interaction between ZnO NRs and GO. The band gap of the ZnO NRs:GO nanocomposite is lower (2.95eV) compared to that of ZnO NRs (3.11 eV), as determined from the analysis of UV absorbance spectra. The ZnO NRs:GO nanocomposite exhibits a broad PL band, from ~450 nm to ~750 nm, with a nearly white-light integrated emission and a chromaticity coordinate of (0.25, 0.34). Gaussian deconvoluted broad PL band exhibits three distinct sub-bands, associated with radiative recombinations in ZnO and GO.
关键词： graphene oxide,optical properties,nanocomposite,ZnO nanorods
更新于2025-09-23 15:21:01
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Grafting of CdTe quantum dots on thiol functionalized MCM-41 mesoporous silica for 68Ga radiolabeling: introducing a novel PET agent
摘要： Radiolabeled fluorescent nanocomposite, 68Ga@CdTeQDs@SH-Propyl@MCM-41, was prepared. The prepared material was characterized using X-ray diffraction, thermal analysis, radio-thin layer chromatography, field Emission scanning electron microscopy, transmission electron microscopy and N2 adsorption and desorption measurements. In vivo biodistribution and tumor avidity of the nanoconposite was investigated among the organs of rats bearing fibro sarcoma tumor. The results showed that the mesoporous structure of MCM-41 after functionalization and grafting of quantum dots remains intact and the nanosilica can be labeled with 68Ga radionuclide very fast. The results showed a rapid and high tumor uptake for 68Ga@CdTeQDs@SH-Propyl@MCM-41 which revealed that the tumor uptake is modulated by size and character of the host.
关键词： CdTe Quantum Dots,68Ga-Radiolabeled fluorescent nanocomposite,MCM-41
更新于2025-09-23 15:21:01
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Bandgap-Tuned CuInS <sub/>2</sub> /ZnS Core/Shell Quantum Dots for a Luminescent Downshifting Layer in a Crystalline Silicon Solar Module
摘要： CuInS2 (CIS) quantum dots (QDs) were investigated as a luminescent downshifting (LDS) material that converts near-ultraviolet (UV) light to visible light and were applied to a single crystalline silicon (c-Si) solar module that has no spectral sensitivity in the near-UV region. The bandgap of the CIS/ZnS core/shell QDs was successfully adjusted to ~3 eV, which was adequate for the LDS layer in solar devices, by changing the molar ratio of Cu/In. CIS/ZnS/ZnS core/shell/shell QDs with 59.9% absolute photoluminescence (PL) quantum yield were prepared by the hot-injection method and embedded in ethylene vinyl acetate copolymer (EVA) resin to fabricate QD@EVA films as the LDS layer. The PL intensity of the QD@EVA films under near-UV excitation monotonically increased with increasing QD concentration. The films were attached to a commercial single c-Si solar module. The advantages and drawbacks of the films were discussed based on the results of incident photon-to-electron conversion efficiency and current-voltage curve measurements.
关键词： CuInS2/ZnS,quantum dot,nanocomposite film,solar module,nanophosphor,luminescent downshifting layer,photoluminescence
更新于2025-09-23 15:21:01
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Efficient Cu/rGO/TiO2 nanocomposite-based photoanode for highly-optimized plasmonic dye-sensitized solar cells
摘要： Renewable energy resources play a valuable role in the global increase of energy demand. The research was performed to enhance the performance of plasmonic dye-sensitized solar cells (PDSSCs) by harvesting the maximum sunlight. In this context, the TiO2 nanoparticles for simple DSSCs and the Cu/rGO/TiO2 nanocomposites for PDSSCs were synthesized using the Sol–Gel and chemical reduction method. Authors demonstrated the utilization of synthesized Cu/rGO/TiO2 nanocomposite-based photoanode to fabricate the plasmonic dye-sensitized solar cells (PDSSCs). SEM, EDX, XRD, and UV/Vis techniques were employed to analyze the surface morphology, elemental composition, crystal structure, and absorbance spectra, respectively. Furthermore, IV measurements were performed on the fabricated devices, and it was observed that the Cu/rGO/TiO2 nanocomposite presented an enhanced efficiency of 5.14% in PDSSCs, which is more than that of the DSSCs-based on pure TiO2 nanoparticles. As an enhanced efficiency could be achieved by high optical absorption and electron injection rate, the PDSSCs with Cu/rGO/TiO2 nanocomposite have an enhanced efficiency due to the surface plasmonic resonance. An improved IPCE of 59.79% was also achieved in Cu/rGO/TiO2 nanocomposite-based photoanode, which might be due to the higher surface area of the photoanode.
关键词： Plasmonic dye-sensitized solar cells,Cu/rGO/TiO2 nanocomposite,Surface plasmonic resonance
更新于2025-09-23 15:21:01
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Enhanced electro-optical response of nematic liquid crystal doped with functionalised silver nanoparticles in twisted nematic configuration
摘要： The dipolar and surface plasmon properties of metallic nanoparticles, especially gold and silver NPs made them suitable candidates for doping with LC system, which provides faster switching time, low power consumption in the display devices. The doping of NPs in the LC system influences the physical properties such as dielectric anisotropy, optical anisotropy, elastic constants, viscosity, and conductivity. In this work, we report the effect of doping of hexane thiol functionalized silver nanoparticles (f-AgNps) of average diameter 3-5nm on the electro-optical switching properties of nematic LC 4-trans-pentyl-cyclohexyl cyanobenzene (5PCH) in the twisted nematic geometry. The threshold as well as switching voltages have also reducedin the nanocomposites of 5PCH compared to pure 5PCH. The steepness of the V-T graph necessary for better multiplexing performance and high contrast has increased by 230% in the 0.025 wt% of f-AgNPs doped 5PCH compared to pure 5PCH. The ion current for 0.025 wt% f-AgNPs doped nanocomposites of 5PCH has reduced by 60% compared to pure 5PCH. We have observed faster switching time in f-AgNPs nanocomposites compared to pure 5PCH due to the decrease of visco-elastic ratio. The total response time of 0.05 wt% f-AgNPs nanocomposites is reduced by 19% compared to pure 5PCH.
关键词： nematic LC,visco-elastic ratio,ion current,nanocomposite,Twisted nematic,response time
更新于2025-09-23 15:21:01
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Polarization selective metasurface formed by interference laser writing
摘要： Polarization dependent optical response of the periodically nanostructured SiO2-Ag nanocomposite material is investigated. As a result of the laser-based surface structuring, the reflection is found to be particularly enhanced and blueshifted for parallel polarisation. This result is attributed to the interaction between photonic and plasmonc resonances, namely to the coupling of the grating caused Rayleigh-Wood anomaly mode (described by using grating theory) with localized surface plasmon modes of the embedded Ag nanoparticles (described by using effective medium approach). The laser-induced formation of such metasurface allows precise control of the effect that is essential for practical application in photonics devices and optical filters.
关键词： photonic resonances,plasmonic resonances,polarization selective metasurface,interference laser writing,SiO2-Ag nanocomposite
更新于2025-09-23 15:21:01
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Structural, thermal and optical characteristics of laser-exposed Pd/PVA nanocomposite
摘要： Nanocomposite of polyvinyl alcohol (PVA) and nanosize palladium (Pd) were fabricated by ex situ casting technique. The fabricated Pd/PVA nanocomposite film has been exposed to infrared pulsated laser with fluences in the range 2–20 J/cm2. The effect of the laser radiation on the structural, thermal and optical properties of Pd/PVA has been investigated using XRD, TGA and UV–Vis spectroscopy. Exposure of IR laser radiation raises the refractive index from 1.84 to 3.38 at 700 nm which confirms the predominance of crosslinking process in the Pd/PVA nanocomposite. Furthermore, the reduction in the optical energy gap from 1.87 to 1.72 eV could be attributed to the increase in the structural disorder resulting from the coordination reaction between OH of PVA and Pd nanoparticles. The attained results reveal that the IR laser radiation enhances the dispersion of Pd nanoparticles in the PVA matrix resulting in more compact structure of Pd/PVA nanocomposite. Consequently, the onset temperature of decomposition increased upon laser irradiation. Commission Internationale de E’Claire (CIE units x, y and z) methodology was employed to describe the color of the studied samples. The color difference between the exposed nanocomposite films and the non-exposed one was raised from 5.63 to 12.01 as the laser fluence increases up to 20 J/cm2. Thus, the present study suggests that the IR laser radiation affects the microstructure of the Pd/PVA nanocomposite which in turn assists in tailoring the thermal and optical properties of such nanocomposite for usage in optoelectronics applications.
关键词： Nanocomposite,XRD,UV spectroscopy,Thermal analysis,Color
更新于2025-09-23 15:21:01
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Optoelectronically suitable graphene oxide-decorated titanium oxide/polyaniline hybrid nanocomposites and their enhanced photocatalytic activity with methylene blue and rhodamine B dye
摘要： Organic–inorganic photocatalytic hybrid nanocomposites based on titanium oxide nanoparticle and polyaniline decorated with graphene oxide were synthesized via in situ chemical oxidative method using ammonium persulphate as an initiator and different weight percentages of TiO2 nanoparticles. The materials were characterized by using conventional techniques like UV–vis spectroscopy, FT-IR spectroscopy and X-ray diffraction. The electrical conductivity of the nanocomposites was found in the range of semiconducting materials. The nanocomposites possess broad application prospects covering the field of semiconducting devices, solar cells, sensors, microwave-absorbing materials and so on. The nanocomposites also exhibit promising photocatalytic activity towards degradation of methylene blue (MB) and rhodamine B dye in the presence of UV-light radiation. Compared to pure PANI and TiO2 nanoparticles, the GO/PANI/TiO2 nanocomposite showed much improvement in degradation efficiency. Significant photodegradation was observed with the molecules where 98.9% degradation was noted with 20% of TiO2 nanoparticles within 1 h under short-wavelength UV-light.
关键词： Fluorescence emitter,Photocatalysis,Optoelectronics,GO/PANI/TiO2 nanocomposite,TiO2 NPs,Semiconductor
更新于2025-09-23 15:21:01