Browsing by Author "Mercuur, James Winston"

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    Hybrid two-dimensional perovskite semiconductor layers for electronic applications
    (Universty of the Western Cape, 2024) Mercuur, James Winston; Arendse, Christopher
    Perovskite materials have emerged as a frontier in advanced functional materials, offering a versatile platform for various applications ranging from solar cells to light-emitting devices. Among the different fabrication techniques, Chemical Vapor Deposition (CVD) stands out for its ability to produce high-quality thin films with precise compositional control. This study delves into synthesising a two-dimensional (2D) hybrid perovskite thin film (PEA)2PbCl4 on diverse substrates, marking a significant advancement in the scalable production of perovskite-based devices. Optimising CVD parameters enabled the deposition of a PbCl2 precursor thin film and its subsequent conversion to the perovskite through an intercalation reaction with PEACl. X-ray diffraction (XRD) analysis, complemented by Rietveld refinement and VESTA simulations, confirmed the hybrid 2D structure of the (PEA)2PbCl4 with an inorganic octahedral layer number (n) equal to one. Scanning electron microscopy revealed a uniform distribution of columnar structures (~120 nm in diameter) for PbCl2 and a woven-like morphology for the perovskite. Optical properties assessed via UV-Vis spectroscopy indicated a band gap of 3.47 eV (Tauc plot) and 3.644 eV (Elliott model) for the perovskite. The perovskite Urbach energy (EU) was estimated at ~236 meV (Urbach method), suggesting significant disorder within the film. However, exciton binding energies were approximately 20 meV, as per the Elliott fit. Photoluminescence spectroscopy showed broadband self-trapped exciton emissions centred at ~532 nm with a full width at half maximum (FWHM) of 140 nm, attributed to intrinsic lattice distortions. These findings contribute to understanding the structural and optical properties of 2D hybrid perovskites and the potential of CVD synthesis, with implications for their application in optoelectronic device fabrication.