Browsing by Author "Adekoya, Joseph Adeyemi"

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    Canfieldite Ag8SnS6 nanoparticles with high light absorption coefficient and quantum yield
    2023
     | Elsevier
    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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    Heterostructures of Ag₂FeSnS₄ chalcogenide nanoparticles as potential photocatalysts
    2023
     | Elsevier
    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 UV-Visible 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.
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