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Nanocomposite material that protects against laser attack
摘要： An international group of researchers has produced a new biologically based optical-nanocomposite material that helps protect against strong light. The material, which consists of biologically generated elemental tellurium nanocrystals as well as a polymer, could protect electronic devices from attack by high-intensity bursts of light, such as emitted by common lasers aimed at aircraft, drones, surveillance cameras and other equipment, and could also find applications in improving the capacity of high-speed optical networking.
关键词： Nanocomposite material,tellurium nanocrystals,laser attack protection,high-speed optical networking,biologically generated
更新于2025-09-11 14:15:04
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Effect of carbon quantum dots on the optical and electrical properties of polyvinylidene fluoride polymer for optoelectronic applications
摘要： In this work, the effect of carbon quantum dots (CQDs) on the optical and electrical properties of polyvinylidene fluoride (PVDF) has been investigated. Different weight percent (0, 1, 3, 5 and 10 wt%) ratios of CQDs/PVDF nanocomposite films were prepared using solution casting technique. The morphological properties of CQDs were examined using a transmission electron microscope (TEM). The optical properties of the prepared plain PVDF and CQDs/PVDF nanocomposite films were measured using UV–Visible spectrophotometer in the wavelength range 190–1200 nm. The direct energy band gap (Eg dir.) of the prepared films decreases from 5.28 to 2.96 eV as the wt% ratio of CQDs/PVDF increases from 0 to 10.0%. The DC electrical conductivity (σDC) of the prepared nanocomposite films are measured in the temperature range from 298 to 398 K. The electrical conductivity of the nanocomposite films has been enhanced six times in magnitude as compared with that of the plain PVDF film, as the wt% ratio of CQDs/PVDF increases up to 10 wt%. The enhancement in the optical and electrical properties of PVDF makes it as a novel candidate in various optoelectronic applications.
关键词： Optical properties,Electrical properties,Polyvinylidene fluoride,Nanocomposite films,Carbon quantum dots
更新于2025-09-11 14:15:04
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Polycarboxyl metal–organic framework UiO-66-(COOH)2 as efficient desorption/ionization matrix of laser desorption/ionization mass spectrometry for selective enrichment and detection of phosphopeptides
摘要： Specific enrichment and efficient detection of phosphopeptides are important for phosphoproteomic analysis. Metal–organic frameworks (MOFs) have been proved to be effective enrichment materials combined with the analysis of mass spectrometry. In this work, we have developed a polycarboxylic group MOF-UiO-66-(COOH)2 used as both efficient enrichment material for phosphopeptides and efficient desorption/ionization matrix of laser desorption/ionization time-of-flight mass spectrometry (LDI-TOF MS) without elution. The crystal is spherical and the particle size is about 200 nm. When using it as enrichment material and MS matrix, phosphopeptides of β-casein can be efficiently detected under superior low detection limits of 1 fmol μL?1, and at an extremely low molar ratio of phosphoprotein/non-phosphoprotein (1:2000) mixtures, there are still four phosphopeptides that can be observed. When detecting real samples, most phosphopeptides of non-fat milk and human saliva can be observed, which is comparable with the literature.
关键词： Metal–organic frameworks,Nanocomposite,Specific adsorption,Matrix of MALDI-TOF MS
更新于2025-09-11 14:15:04
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CH3NH3PbBr3 Nanocrystals Formed in situ in Polystyrene Used for Increasing the Color Rendering Index of White Leds
摘要： A new method is proposed for the formation of MAPbBr3 nanoparticles in situ in a dispersion of polystyrene in toluene in the absence (MAPbBr3@PS) and presence of a broad-band luminophor (MAPbBr3/GAG:Ce@PS). This method permits the lossless use of perovskite, a uniform distribution of the luminophor nanoparticles in the polymer matrix, and maintenance of a high photoluminescence quantum yield (~46%). The samples derived from MAPbBr3 have green photoluminescence with a maximum showing a blue shift in going from bulk perovskite powder to films due to a size effect. The use of nanocomposite films MAPbBr3/GAG:Ce@PS in white LEDs permits enhancement of the color rendering index to 92 with correlation color temperature >5800 K.
关键词： nanocomposite films,quantum yield,photoluminescence,hybrid halide perovskite
更新于2025-09-11 14:15:04
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Effect of Annealing Treatment on Optical and Electrical Properties of PCDTBT:Graphene Hybrid Structure for Photovoltaic Application
摘要： Indium tin oxide (ITO)/poly[N-9￠-heptadecanyl-2,7-carbazole-alt-5,5-(4,7-di-2-thienyl-2￠,1￠,3￠-benzothiadiazole)] (PCDTBT):graphene/Al structures have been elaborated. By applying a specific elaboration method, we succeeded in dispersing expandable graphene oxide in organic solvent (N,N-dimethylformamide, DMF) to obtain graphene oxide and insert it into a PCDTBT matrix. The effect of annealing treatment of PCDTBT:graphene films on the optical and electrical properties were studied. The obtained results showed a remarkable effect of the annealing treatment on the optoelectronic properties. The ultraviolet–visible (UV–Vis) spectra showed that the light harvesting was increased and the orderly stacking of the polymer chains was enhanced. The photoluminescence results showed a red-shift of about 10 nm in case of heat treatment at 150°C, related to an increase of the conjugation length of the polymer chains. The electrical parameters, such as the series resistance (Rs), ideality factor (n), and barrier height (/b), were calculated. We found that thermal annealing reduced both the series resistance Rs and barrier height value /b, significantly. These results indicate that annealing treatment improves the transport phenomenon in the active layer. In addition, the Log(J)–Log(V) curves suggested that the charge transport is governed by a space-charge-limited mechanism current. The effective carrier mobility (leff) was on the order of 10?5 cm2/V.
关键词： annealing treatment,hybrid structure,PCDTBT,graphene oxide,bulk heterojunction,Nanocomposite
更新于2025-09-11 14:15:04
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MoS2 decorated with graphene and polyaniline nanocomposite as an electron transport layer for OLED applications
摘要： The incorporation of two-dimensional MoS2 and GO (graphene oxide) into polyaniline (PANI) matrix emerges as a productive way for the enhancement in electrical and optical assets of pure PANI. The ternary nanocomposite PANI–rGO–MoS2 (PGM) is synthesized via in situ chemical oxidative polymerization of aniline monomer using ammonium persulfate (APS) as an oxidant with varying MoS2 contents. The surface morphological images of PGM nanocomposites declared the coating of PANI nanofibers, and GO sheets over stacked MoS2 sheets are investigated by field emission scanning electron microscope and transmission electron microscope. The interaction between polyaniline, reduced graphene oxide, and molybdenum disulfide was established by Fourier transform infrared spectroscopy and Raman spectroscopy. The bandgap was calculated for optimized PGM3 nanocomposite, nearly 1.21 eV with a relatively slow decay component and a higher non-radiative rate of electron–hole recombination. The photoluminescence spectra of PGM3 nanocomposite showed four bands: violet, blue, green–blue, and green. The chromaticity was observed in the deep blue region with a color purity of 70%. The conductivity of the optimized PGM3 nanocomposite was enhanced by 184.43% as compared to pristine PANI. These results justified that the optimized PGM3 nanocomposite is a suitable candidate as an effective electron transport layer for high performance in organic light-emitting diode (OLED) devices.
关键词： graphene oxide,MoS2,nanocomposite,electron transport layer,OLED,polyaniline
更新于2025-09-11 14:15:04
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Influence of gamma radiation on microshear bond strength and nanoleakage of nanofilled restoratives in Er, Cr:YSGG laser-prepared cavities
摘要： Objective: To evaluate the effect of gamma radiation on microshear bond strength and nanoleakage of nanofilled restoratives in laser-prepared cavities. Materials and Methods: Twenty?eight flat buccal dentin surfaces were prepared for microshear bond strength test. Er, Cr:YSGG laser was used to prepare another 28 Class V cavities on the buccal surfaces of the molars. All teeth were divided into four groups; 1st group: Application of Filtek Z350 nanocomposite material, 2nd group: As the 1st group and then exposure to gamma radiation, 3rd group: Application of Ketac N100 nanoglass ionomer, and the 4th group: As the 3rd group and then gamma irradiated. The bond strength test was performed after storage in artificial saliva for 24 h. For the nanoleakage test, teeth were submerged in a solution of ammoniacal silver nitrate, sectioned, and then examined under a scanning electron microscope. The collected data were statistically analyzed. Results: Nanocomposite showed higher bond strength values than nanoglass ionomer. Despite the fact that gamma radiation did not decrease nanocomposite bond strength, it decreased nanoglass ionomer bond strength. Nanoglass ionomer-restored cavities showed higher silver ion penetration than nanocomposite in both control and gamma-irradiated groups. Conclusion: Gamma radiation has no effect on bond strength and nanoleakage of nanocomposite so that it can be placed before radiotherapy. On the other hand, the bond strength of nanoglass ionomer was adversely affected by gamma radiation.
关键词： nanoleakage,gamma radiation,Bond strength,Er, Cr:YSGG laser,nanocomposite,nanoglass ionomer
更新于2025-09-11 14:15:04
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Femtosecond-laser-ablation induced transformations in the structure and surface properties of diamond-like nanocomposite films
摘要： Femtosecond laser ablation processing is applied for surface modification and micropatterning of diamond-like nanocomposite (DLN) films (a-C:H:Si:O films). Using a visible femtosecond laser (wavelength 515 nm, pulse duration 320 fs), microgroove patterns have been fabricated on the DLN films, aimed at further studies of their properties. The studies were focused on (i) structural transformations in the surface layers using Raman spectroscopy and transmission electron microscopy (TEM), (ii) wettability of laser-patterned films, and (iii) nano/microscale friction properties of laser-patterned DLN films using lateral force microscopy. Raman spectroscopy and TEM data showed characteristic features of the surface graphitization during ultrashort-pulse ablation. High resolution TEM study of the microgrooves revealed the formation of cubic SiC nanocrystals (4–8 nm size) on the laser-ablated surface. The water contact angle measurements showed anisotropic wetting behavior of the grooved surfaces (the contact angle was different in the directions parallel and perpendicular to microgrooves), depending on the groove depth (aspect ratio). Lateral force microscopy examination (with micro-sized Si tips) showed that the laser-patterned regions exhibited low friction properties compared to the original surface. The obtained results demonstrate that femtosecond laser processing is an effective technique to generate new properties of hard DLN coatings at the micro and macroscale.
关键词： Diamond-like nanocomposite films,Femtosecond laser ablation,Micropatterning,SiC nanocrystals,Graphitization,Wettability
更新于2025-09-11 14:15:04
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Synthesis of magnetically reusable Fe3O4/TiO2-N, P co-doped graphene quantum dot nancomposites using hexachlorocyclophosphazene; high photoluminance property and photocatalytic promoter
摘要： Hexachlorocyclophosphazene (PNT) was used as new P and N doping source for synthesizing of graphene quantum dots (N,P-GQDs). Hydrothermal process was applied for importing P and N atoms into the GQDs texture. Three different amounts of hexachlorocyclophosphazene were used to obtain optimum sample. All products were characterized using XRD, SEM, PL, FT-IR, EDS, AFM, TEM and Raman spectroscopy. XRD result indicated that the sample with 0.1 g of PNT (sample 2) has sharp peaks with medium wide and intensity and has a more principle in structure in comparison with other samples. So sample 2 was chosen as optimum sample. Also sample 2 showed strongest PL emission under excitation at 396 nm which was an evidence of successful doping of P and N atoms in the GQDs structure during hydrothermal process. The Fe3O4/TiO2/N,P-GQDs nanocomposite which was obtained using S2 as N,P-GQDs source showed a high activity in organic dye degradation. The higher catalytic activity of Fe3O4/TiO2/N,P-GQDs versus TiO2 can be attributed to the synergistic effect between TiO2 and N,P-GQDs. The magnetic properties of the catalysts allow fast separation of the catalysts from the reaction media.
关键词： Hexachlorocyclophosphazene,Fe3O4/TiO2/N,GQDs,Citric acid,P-GQDs nanocomposite,Photoluminescence
更新于2025-09-11 14:15:04
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Preparation of ZnS-CdS Nanocomposite for Photoelectrochemical Hydrogen Production
摘要： Chalcogenide nanostructures and nanocomposites as semiconductors have attracted intense attentions in various potential applications such as hydrogen production owing their remarkable photoelectrochemical activity. In this study, ZnS-CdS nanocomposite with cubic ZnS and hexagonal CdS was synthesized with a simple wet chemical method. As can be seen from SEM and TEM images, CdS was formed on the outer layer of ZnS NPs. The hydrogen production rate of ZnS-CdS nanocomposite was much higher than that of ZnS NPs, indicating the remarkable enhancement of hydrogen production activity of photocatalyst with the addition of CdS. The hydrogen production rate increased more than 4 times after the deposition of Ru on the surface of ZnS-CdS. In addition, the as-prepared ZnS-CdS nancomposite demonstrated an excellent stability over 50 h.
关键词： CdS,Nanocomposite,ZnS,Hydrogen,Photoelectrochemicallysis
更新于2025-09-11 14:15:04