Synthesis of TOPO-capped Nanocrystals of Copper Sulphide from a Single-source Precursor, [Cu(S2CNMe(nHex))2]

Nearly mono-dispersed TOPO-capped copper sulphide nanocrystals of ca. 4.5 nm (diameter) have been synthesized from [Cu(S2CNMe(nHex))2]. The absorption spectrum of the (Cu2S) nanoparticles shows a large blue shift (2.09 eV) in relation to bulk Cu2S (1022 nm, 1.21 eV). The PL gives a broad spectrum with an emission maximum at 477 nm. The HRTEM of the nanoparticles shows clusters of particles on the copper grid with clear lattice fringes. South African Journal of Chemistry Vol.57 2004: 40-4

Indium Chalcogenide Nanomaterials in the Forefront of Recent Technological Advancements

In the last decade, there has been an increasing trend in the exploitation of indium chalcogenides in various applications which range from water splitting reactions in renewable energy to degradation of dyes in environmental rehabilitation. This trend is attributed to the interesting and unique properties of indium chalcogenide nanomaterials which can be easily tuned through a common approach: particle size, shape and morphology engineering. In this chapter, we outline the preferred attributes of indium chalcogenide nanomaterials which are deemed suitable for recent applications. Furthermore, we explore recent reaction protocols which have been reported to yield good quality indium chalcogenide nanomaterials of multinary configurations, e.g. binary and ternary compounds, among others

Progress in Green Solvents for the Stabilisation of Nanomaterials: Imidazolium Based Ionic Liquids

For over a decade, ionic liquids (ILs) have attracted enormous attention from scientists across the globe. The history of these compounds traces back to 1914 where the inception of the first IL with a melting point of 12°C was made. Years later, a progression of the remarkable related compounds have been discovered. Out of many analogous compounds realized from time to time, the imidazolium class of ionic liquid is the most studied because of their air and moisture stability. The physicochemical properties of ILs differ significantly depending on the anionic/cationic species and alkyl chain length. ILs have found application in many scientific fields the most recent being good solvents and stabilizing agents in the nanomaterial synthesis. Studies have showed that ILs not only stabilize as synthesized nanomaterials but also provide environmentally green routes towards nanomaterials engineering

Fiber-Matrix Relationship for Composites Preparation

Fiber-matrix interaction at the interphase is one very important property that is of great concern to all polymer scientists involved in polymer composites. Many of the failures can be traced to the type of interfacial interaction existing in the composites. That is why highlighting the factors that dictate the type of and the extent of interactions at the interphases become very necessary. Natural fiber polymer composites have found application in many fields of human endeavors. To continue this growth being experienced, the factors that determine the formation of good interaction at the interphase most be understood, so that they can be manipulated for a better result

Improving the Mechanical Properties of Natural Fiber Composites for Structural and Biomedical Applications

Natural fiber composites are designed for different purposes including structural and non-structural ones. These natural fiber composites vary greatly in their properties including mechanical properties. Mechanical properties which include the tensile and flexural properties are highly dependent on factors such as matrix type, filler type, processing, post processing treatment and many more, factors which are quite application specific. However, many research works develop their natural fiber composite before considering the possible applications. This chapter intends to X-ray the factors that affect the mechanical properties as it relates to structural and biomedical applications and suggest ways of improving the mechanical properties

Band Structure, Morphology, Functionality, and Size- Dependent Properties of Metal Nanoparticles

Metallic nanoparticles are gradually emerging as important materials because of their novel shape and size-dependent chemical and physical properties that differ drastically from their bulk counterparts. The main challenges in the field of nano-chemistry are the rational control and manipulation of synthesis to derive materials with one of their dimensions in nanometer regime, and upscale production of nanomaterials for device fabrication. This chapter reviews the fundamentals of the quantum properties of metals and quantum mechanical size effects with special focus on clusters of Pd, Pt, Au and Ag. Effects of reduction in size of metal nanoparticles to nanoscale on their various properties (structural, thermal, mechanical, chemical, electronic, magnetic and optical) are reviewed. The chapter concludes with a review of select medical applications of metal nanoparticles

Heterostructures of Ag2FeSnS4 chalcogenide nanoparticles as potential photocatalysts

The synthesis of photocatalysts with a suitable bandgap that could speed up the rate of oxidation of chemical effluent is of utmost importance to material chemists. It has been observed that chalcogenide nanostructures research continues to dominate scientific work over the last few years based on their exciting bandgap within the semiconductor bandgap range. In this research work, novel class I2-II-IV-VI4 quaternary chalcogenides nanoparticles were synthesised using co-precipitation by varying the reaction conditions of temperature (200 °C and 250 °C) and, essentially, capping agents (citric acid and glycerol) and the mole ratio of precursors. The resulting nanoparticles were purified and vacuum dried to give a black crystalline solid. The Powder-X-ray Diffraction analysis of the as-synthesised heterostructure chalcogenides showed novel pure phase materials that exhibited the orthorhombic and cubic Ag2FeSnS4 crystal systems reminiscent of the parent compounds Ag8SnS6 and AgSnS2 under different experimented reaction conditions. The morphological characterisation of the HC chalcogenides by Transmission Electron Microscope revealed that the nanomaterials formed were predominantly nanocubes, with particle diameters ranging from 22.98 ± 1.67 to 57.26 ± 12.93 nm. Further elucidation of the optical property of the HC nanoparticles by Tauc's plot based on the data derived from UV-Vis spectrophotometry measurement revealed that the bandgap ranged from 1.58 to 1.99 eV. The FTIR absorption character of the as-synthesised HC nanoparticles provided evidence for the surface functionalisation, confirming the presence of moieties like the hydroxyl (O-H) at 3396.16 cm−1 and carbonyl group (C=O) at 1712.31 cm−1. At the same time, the UVVisible spectrophotometry, measured over a range of 250 to 1000 nm, showed broad absorbance between 420 and 800 nm, confirming the optical property of the nanoparticles. The result showed that heterostructure chalcogenide nanoparticles would have an excellent photocatalytic application

Canfieldite Ag8SnS6 nanoparticles with high light absorption coefficient and quantum yield

Canfieldite Ag8SnS6 (STS) nanocubes were prepared by the solution decomposition of precursors using heat-up and hot injection protocols employing coordinating solvents (oleylamine - OLA and dodecanethiol - DT) to afford monodispersed silver tin sulfide (STS) nanoparticles. The phase and shape of nanoparticles were tuned by varying reactants' temperature and mole ratios. The powder X-ray diffraction (p-XRD) and transmission electron microscopy (TEM) analysis indicate phase pure orthorhombic Ag8SnS6 nanocrystals with nearly monodispersed particles ranging between 12 and 50 nm. The p-XRD patterns for the STS nanoparticles obtained by the heat-up method exhibited enhanced peak broadening than the hot injection route, accounting for the corresponding quantum confinement effects. Likewise, the (124), (227) and (266) planes of the reflections in OLA/DT capped STS crystals appeared well resolved, indicating that seed growth of a transitional Ag2S might be involved in the formation of the ternary chalcogenides. The values of the energy bandgap (Eg) were found in the range of 1.16–2.60 eV. At the same time, the STS nanoparticles exhibited high photon absorption and low quantum yield potentials, making them a possible candidate for photovoltaic cells and enhanced photoelectrochemical performance

Synthesis of polyol based Ag/Pd nanocomposites for applications in catalysis

The synthesis of polyvinylpyrrolidone seed mediated Ag/Pd allied nanobimetallic particles was successfully carried out by the simultaneous reduction of the metal ions in ethylene glycol, diethylene glycol, glycerol, pentaerythritol and sodium borohydride solution. The optical measurement revealed the existence of peak broadening that causes diffusion processes of the metal sols to decrease making it possible to monitor the changes spectrophotometrically. This, together with X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and high resolution TEM measurements strongly support the conclusion that intimately alloyed clusters were formed and the particle growth anisotropy is diffusion limited. Finally, the catalytic potential of the nanocomposites was investigated using 4-nitrophenol in the presence of sodium borohydride at 299 K; a good linear fitting of ln (A/A0) versus the reaction time was obtained, indicating pseudo-first-order kinetic