Papers by Keyword: Metal Nanoparticle

Abstract: This abstract focuses on the green synthesis of copper nanoparticles (CuNPs), a significant class of nanoparticles with diverse applications. Green synthesis methods, such as plant extracts, microbial-mediated synthesis, and eco-friendly reducing agents, offer several advantages including low cost, scalability, and reduced environmental impact. Utilizing natural sources such as plant extracts rich in phytochemicals and microorganisms capable of reducing metal ions, CuNPs can be synthesized efficiently under mild conditions without the need for rigid chemicals. In recent years, the synthesis of nanoparticles has garnered significant attention due to their unique properties and diverse applications in various fields, including catalysis, electronics, medicine, and environmental remediation. Among the different methods available for nanoparticle synthesis, green synthesis has emerged as a promising approach due to its eco-friendly nature and potential for large-scale production without harmful by-products. Copper nanoparticles (CuNPs) have gained particular interest owing to their exceptional properties and wide-ranging applications. This work explores the green synthesis of copper nanoparticles, focusing on the principles, methods, characterization techniques, and applications of these environmentally nanomaterials.

Abstract: Graphite encapsulated nickel nanoparticles were prepared by ball-milling and subsequent annealing a mixture of expanded graphite and nickel powders. The products were characterized by transmission electron microscope (TEM), and their tribological behavior used as lubricating additive was investigated by using a high-temperature tribo-tester. The morphology of the worn tribo-surfaces was observed by scanning electron microscope (SEM). The results show that as-prepared graphite encapsulated nickel nanoparticles with a size range of 10-150 nm have a marked anti-friction and wear resistance effect, and the larger the applied load, the lower the friction coefficient and the wear severity.

Abstract: The effect of surface modification by nanoparticles of metal compounds was investigated by means of gas and vapor adsorption analysis. The surface of activated carbon fiber cloths was modified by loading of Li2CO3 and MgO nanoparticles. The particles on the carbon surface played as initial adsorption site of water molecules, leading to the promotion of micropore filling without diminishing the micropore volume of the porous carbon supports. The increasing characteristic adsorption energy suggested some interaction between methane molecules and the particles.

Abstract: The silver NanoPaste® having silver nanoparticles with 5 nm in average diameter, coated either on a polyimide substrate or a copper one, is successfully sintered with CW lasers. A rapid metallization from the paste surface with the visible laser makes the evaporation of solvent and dispersant difficult, resulting in an insufficient sintering with large pores. In contrast, the near-infrared laser with a little absorption in the paste heats the substrate first, and then develops metallization up to the paste surface, so that an easy evaporation makes the structure denser. No peeling was observed at the interface of the laser-sintered Ag film and the substrates. Its adhesive strength is nearly equal to that of the furnace-sintered sample.

Abstract: Photoluminescence of di-ureasil hybrids containing homogeneously dispersed Ag nanoparticles, covered with silica shells was investigated at room temperature and compared with emission of undoped hybrids. Metal-doped di-ureasils show a broad emission band in the blue spectral region similar to what has been observed in pure di-ureasils but with lower relative intensity. A broad minimum arises around 438 nm for Ag@SiO2 - containing di-ureasils which coincides with the peak of plasmon resonance band in the absorption spectrum. This behaviour can be attributed to inner filtering effect, which manifests itself as absorption by metal nanoparticles of light emitted from the matrix. Low-temperature time-resolved spectroscopy and lifetime measurements demonstrate that changes are induced in the time-scale behind the di-ureasil host emission when the nanoparticles are incorporated. In particular, the lifetime values for Ag@SiO2- doped di-ureasils are smaller than those measured for the undoped host, suggesting that energy transfer might exist between the hybrid's emitting centres (NH groups and siliceous nanodomains) and the nanoparticles.

Abstract: Site-defined metal microstructure was fabricated on the pre-designed organic template via a surface modification of Si(100) wafer. Site-defined substrate with octadecyltrichlorosilane (OTS) was oxidized by AFM (Atomic Force Microscopy) at threshold voltage (Vo). Terminal group (-CH3) of OTS was changed into carboxyl group (-COOH). Then, locally modified monolayer surface was used to induce the site-selective self-assembly of different materials (organic, metal, and semiconductor), according to the predefined patterns. The target metal selected is copper ions for the feasibility examination of conductive metal line fabrication