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- 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.
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- Exploitation of agricultural waste as green starting materials to produce various valuable products is attracting the attention of academic, industrial and other practitioners. Cashew nut shell (CNS) and its liquid extract (CNSL) in particular have been identified as agro-wastes rich in valuable and functional renewable products. The unique structural features of the CNSL constituents offer the possibility for different modifications to suit various applications. This review article provides recent developments in CNS and CNSL as green sources for use in the production of biorenewable chemicals, materials and energy. Extraction methods and applications of CNS, CNSL and isolates are discussed. Furthermore, a literature survey of the current status and efforts made on the utilization of these agricultural and food wastes for different applications is well outlined.
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- A distorted single crystal structure of bis(piperidinedithiocarbamato)lead(II) complex and its subsequent use to deposit thin films is reported. Two deposition routes namely, aerosol-assisted chemical vapour deposition (AACVD) and spin coating deposition have been employed to obtain anisotropic lead sulfide (PbS) nanostructures. The thin films displayed rod to cubic shaped crystals for AACVD, and a range of cubes, star and dendritic morphologies with variation of temperatures were displayed for spin coated films. Optical band gaps between 1.32 and 1.55 eV as controlled by the change in temperature were observed for thin films deposited by AACVD. Powder X-ray diffraction (P-XRD) studies show that the films formed are composed of cubic crystalline PbS. The X-ray photoelectron spectroscopy (XPS) was used to investigate the effect of activation temperatures (350, 400 and 450 °C) on the chemical composition and oxidation states of PbS samples.
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- Copper sulfide thin films and nanoparticles have been prepared via aerosol assisted chemical vapour deposition and solvothermal hot injection routes, respectively. Both routes employed heterocyclic amine based benzoylthioureato-copper(II) complexes as single source precursors. Copper sulfide thin films of diverse morphologies ranging from cubic to snowy or irregular crystallites depending on the deposition temperature were observed. Powder X-ray diffraction studies of the as deposited thin films have indicated the formation of hexagonal and cubic phases of copper sulfide. In the case of the nanoparticles, Roxbyite (Cu1.75S) phase was obtained in dodecanethiol at temperatures of 150, 190 and 230 °C. However, a preferred growth of nanoparticles was observed in the presence of oleylamine whereas the roxbyite phase was obtained at temperatures of 150, 200 and 250 °C. Also transmission electron microscopy showed the formation of close to spherical, hexagonal nano-disk and rod shaped nanoparticles.
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- 2021| Scientific and Techn...Cadmium dithiocarbamate and cadmium ethyl xanthate complexes were synthesized and characterized by microanalysis, Fourier transform infrared (FT-IR) spectroscopy and thermogravimetric analyses. The complexes were employed as molecular precursors for the fabrication of CdS nanoparticles in hexadecylamine (HDA) and oleylamine (OLA) at a temperature of 250 C. Spherical and oval shaped particles with sizes ranging from 9.93±1.89 to 16.74±2.78 nm were obtained in OLA while spherical, oval and rod shaped particles with sizes ranging from 9.40±1.65 to 29.90±5.32 nm were obtained in HDA. Optical properties of the nanoparticles showed blue shifts as compared to the bulk CdS, with the OLA capped nanoparticles slightly more blue shifted than the corresponding HDA capped nanoparticles. Results of crystallinity patterns revealed hexagonal phase of CdS.
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- A series of Fe(III), Co(III), Ni(II), Cu(II), Zn(II) and In(III) N-morpholine-N'-benzoyl thiourea complexes have been synthesized and characterized by elemental analysis, thermal analysis, infrared spectroscopy, 1H nuclear magnetic resonance spectroscopy and single-crystal X-ray crystallography. Thermogravimetric analysis shows that all the complexes undergo a two-step decomposition process except for the iron(III) complex and the indium(III) complexes, which show three-step and one-step decompositions, respectively. The complexes are thermally stable up to approximately 300°C. The ligand coordinates the various metal ions in a bidentate (L-kO,S) chelating mode, facilitated by deprotonation of the acidic amide (–C(O) N'HC (S)) moiety. This mode of coordination allows for the facile formation of neutral bis/tris-6-membered chelates of type [M(L-kS,O)x] where x = 2 or 3 for divalent or trivalent metal ions, respectively.
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- Recently, the incorporation of single-source molecular precursors in synthetic protocols has been identified as an effective and easy route toward tuning the sought-after properties of thin films. In this work, bis-tetrahydroquinolinedithiocarbamato complex of lead(II) has been used as a single-source molecular precursor to deposit PbS thin films at elevated temperatures. The spin coating method was chosen as a deposition technique to afford PbS thin films. The morphology of the obtained films was observed to be influenced by the variation of temperature. Formations of compact thick and agglomerated spherical granules were observed at a lower temperature whereas elevated temperatures afforded the formation of cubic and multipodal shaped structures. From the energy dispersive X-ray spectroscopy (EDS) results, the elemental ratio of the finally formed films agree with the PbS composition. X-ray diffraction studies further revealed the formation of the crystalline cubic phase of PbS films with a calculated crystallite size in the range of 50 − 58 nm.
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- Synthesizing nanoparticles with the less environmentally malignant approach using plant extract is of great interest; this is because most of the chemical approaches can be very costly, toxic, and time‐consuming. Herein, we report the use of Acacia senegal leaf extracts to synthesize silver nanoparticles (AgNPs) using an environmentally greener approach. Silver ions were reduced using the bioactive components of the plant extracts with observable colour change from faint colourless to a brownish solution as indication of AgNP formation. The structural properties of the as‐synthesized AgNPs were characterized using powder X‐ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and UV‐Vis absorption spectrum. Antimicrobial assessment of the as‐synthesized AgNPs was explored on some strains of gram‐positive and gram‐negative bacteria. The obtained results indicate that the as‐synthesized AgNPs are pure crystallite of cubic phase of AgNPs, fairly dispersed with a size range of 10–19 nm. The AgNPs were found to be small in size and exhibit significant antibacterial activities, suggesting that the as‐synthesized AgNPs could be used in the pharmaceutical and food industries as bactericidal agents.
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- 2019| Springer NatureCadmium sulfide (CdS) nanoparticles have been synthesized from CdX2 (X = Cl–, I–) complexes of 4-chlorobenzaldehyde and benzophenone thiosemicarbazone. The complexes have been studied by thermogravimetric analysis (TGA), elemental analysis, FT-IR, and NMR spectroscopy. The solvothermal decomposition of the complexes has afforded oleylamine-capped CdS nanoparticles with a wurtzite hexagonal phase. The transmission electron microscopy (TEM) studies show different morphologies which are influenced by reaction temperature and the nature of the ligands on the precursor complexes. Particles in the form of irregular cubes, elongated cubes and nanodendrites have been observed. The UV-Vis spectroscopy measurements show temperature and nature of complex-dependant optical properties. Blue-shifted band gap energies have been observed at lower reaction temperatures.
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