Browsing by Author "Cummings, F"

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    Enhanced electrochemical glucose sensing performance of CuO:NiO mixed oxides thin film by plasma assisted nitrogen doping
    (Elsevier, 2021) Cummings, F; Palmer, M; Masikini, M
    In this study plasma-assisted nitrogen doping of a CuO–NiO mixed oxide thin film was presented. The as prepared film was also applied as a glucose sensor. The nitrogen species generated during plasma ignition resulted in a beneficial phase transformation of CuO to Cu2O. Characterisation techniques such as XRD, SEM, EIS and Hall Effect etc. measurements were utilized to study the morphology, structural features, doping profile and electrical properties of the sensing material. Device performance electrochemical testing showed that the as-developed sensor (labelled as N–CuO/Cu2O:NiO) showed an ultra-fast response time of 2.5 s with high sensitivity (1131 μA/mM.cm2). The linear range of the sensor was calculated to be up to 2.74 mM of glucose and excellent selectivity towards glucose at an applied potential of +0.67 V vs Ag/AgCl in 0.1 M NaOH electrolyte solution.
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    Facile synthesis of NiSe2:α-Fe2O3 thin film: physical, optical and photoelectronic properties
    (Thin Solid Films, 2023) Visser, E; Cummings, F; Cory, N
    In this study, a highly scalable approach to fabricating NiSe2:α-Fe2O3 heterojunction thin film in the absence of a dehydration step or lattice parameter matching was established. The attachment of NiSe2 to α-Fe2O3 leads to an 82% and 97% decrease in charge transfer resistance (with and without illumination respectively) compared to pristine α-Fe2O3. The magnitude of the open circuit potential increased from approximately -0.30 V to -0.42 V vs Ag/AgCl, providing a stronger electric field for charge carrier separation. Charge transfer efficiency was calculated by using a ratio of charge carriers removed and those produced in the bulk. Scanning electron microscopy coupled with the electrodeposition current-time transients study proved that the attachment process involved the progressive nucleation of NiSe2 and the simultaneous cathodic reduction of α-Fe2O3.