Browsing by Author "Nwambaekwe, K.C"

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    Electronics of anion hot injection-synthesized te-functionalized kesterite nanomaterial
    (MDPI, 2021) Nwambaekwe, K.C; Masikini, M; Mathumba, P
    Metal chalcogenides such as copper zinc tin sulfide (CZTS) have been intensively studied as potential photovoltaic cell materials, but their viability have been marred by crystal defects and low open circuit potential (Voc) deficit, which affected their energy conversion efficiency. Strategies to improve on the properties of this material such as alloying with other elements have been ex-plored and have yielded promising results. Here, we report the synthesis of CZTS and the partial substitution of S with Te via anion hot injection synthesis method to form a solid solution of a novel kesterite nanomaterial, namely, copper zinc tin sulfide telluride (CZTSTe). Particle-size analyzed via small angle X-ray scattering spectroscopy (SAXS) confirmed that CZTS and CZTSTe materials are nanostructured. Crystal planes values of 112, 200, 220 and 312 corresponding to the kesterite phase with tetragonal modification were revealed by the X-ray diffraction (XRD) spectroscopic analysis of CZTS and CZTSTe. The Raman spectroscopy confirmed the shifts at 281 cm−1 and 347 cm−1 for CZTS, and 124 cm−1, 149 cm−1 and 318 cm−1 for CZTSTe.
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    Photovoltaic efficiencies of microwave and Cu2ZnSnS4 (CZTS) superstrate solar cells
    (Materials Today Sustainability, 2023) Yussuf, S.T; Nwambaekwe, K.C; Ramoroka, M.E; Iwuoha, E.I.
    Organic and inorganic materials such as perovskites, copper indium gallium diselenide, cadmium telluride, and copper zinc tin sulfide/selenide (CZTS/Se) have been employed to capture unlimited sunlight through the photovoltaic effect. CZTS/Se is regarded as the most promising, most environmentally friendly, most abundant candidate with high absorption coefficient and tunable bandgap for the generation of solar energy. Superstrate architectures have numerous advantages over the substrate architectures and for this reason; it offers a promising route for producing solar cells at a relatively low cost. This article reviews the state-of-the-art knowledge on the synthesis, crystal structure, electronic properties, defects, and secondary phases of CZTS. The CZTS solar cell device architecture and mechanism of the substrate and superstrate configurations were also covered in the review. The preparation of superstrate CZTS via vacuum and non-vacuum methods, as well as their photovoltaic efficiencies were critically discussed. The microwave synthesis and characterization of CZTS nanoparticles were also reviewed with respect to the effect of temperature, surfactant, and reagents on the physical properties of the nanomaterials. The application of microwave-synthesized CZTS nanoparticles in the advancement of thin film solar cells was also critically examined. Finally, the challenges and the prospects of CZTS solar cells were also presented