Repository logo
 

Faculty of Applied Sciences

Permanent URI for this communityhttp://ir-dev.dut.ac.za/handle/10321/5

Browse

Has files: YesSubject: search.filters.subject.Metal oxide semiconductors

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Ion doped metal oxide and its power conversion efficiency influence on Perovskite solar cells
    (2024-09) Reddy, Dwayne Jensen; Lazarus, Ian Joseph
    ABSTRACT Ion Doped Metal Oxide and its Influence on the Power Conversion Efficiency of Perovskite Solar Cells Dwayne Jensen Reddy Doctor of Applied Sciences This study focuses on the fabrication and characterization of Zinc-doped Titanium dioxide (ZnTiO2) as an Electron Transport Layer (ETL) in CH3NH3PbI3-based perovskite solar cells (PSCs). A one-step spin coating technique under controlled ambient conditions (relative humidity < 65%, room temperature ∼ 20oC ) for the development of PSC was applied to investigate the effects of Zn-ion doping on the structural, morphological, optical, and photovoltaic properties. Numerical simulations using SCAPS 1D were additionally performed to further investigate the influence of ion doping on the power conversion efficiency (PCE) of PSCs. Zn-doped TiO2 was successfully incorporated into the TiO2 crystal structure using the solgel technique. Characterization through X-ray diffraction (XRD) and Energy Dispersive X-ray Spectroscopy (EDX) confirmed the incorporation of Zn ions. The crystallite size ranged from 19.99 to 7.1 nm, depending on the Zn ion doping concentration. XRD results also indicate the formation of a highly crystalline tetragonal perovskite (CH3NH3PbI3) phase. Fourier Transform Infrared (FTIR) spectroscopy verified the presence of the anatase phase of Zn-doped TiO2, while the formation of the adduct of Pb2 with dimethyl sulfoxide (DMSO) and methylammonium iodide (MAI) was confirmed at 1015 cm-1. Scanning Electron Microscope (SEM) images exhibited fairly smooth and uniform surface coverage for the Zn-doped TiO2 layers. The Root Mean Square (Rq) values for surface roughness showed a decrease from 26.85 nm for undoped TiO2 to 23.4 nm for the 5 mol% Zn-doped TiO2 layer. UV-Vis spectroscopy demonstrated low light transmission loss characteristics from 300 to 790 nm, with the 2 mol% Zn-doped TiO2 showing slightly improved light transmission between 550 and 800 nm. The bandgap energy of undoped and Zn-doped TiO2 ranged from 3.53 to 3.38 eV, while the perovskite layer exhibited a bandgap energy of 2.06 eV. Experimentally, an optimum PCE of 5.67% was achieved with a 2 mol% dopant concentration. However, increasing the Zn dopant to 5 mol% led to a slight deterioration in the PCE. Numerical simulations revealed that increasing the donor doping concentration in the ETL improved the conduction band alignment at the ETL and perovskite interface, resulting in a PCE of 6.17%. Optimizing the absorber acceptor doping concentration and band gap improved the PCE to 10.79%, however, created a pronounced conduction band offset at the ETL/perovskite interface. This was mitigated by introducing an interfacial layer of Cubic Silicon Carbide (3C-SiC) between the absorber and ETL to minimize the conduction band offset, ultimately achieving a PCE of 12.09%.
  • Thumbnail Image
    Item
    Recent advances on metal oxide based nano-photocatalysts as potential antibacterial and antiviral agents
    (MDPI AG, 2022) Prakash, Jai; Krishna, Suresh Babu Naidu; Kumar, Promod; Kumar, Vinod; Ghosh, Kalyan S.; Swart, Hendrik C.; Bellucci, Stefano; Cho, Junghyun
    Photocatalysis, a unique process that occurs in the presence of light radiation, can potentially be utilized to control environmental pollution, and improve the health of society. Photocatalytic removal, or disinfection, of chemical and biological species has been known for decades; however, its extension to indoor environments in public places has always been challenging. Many efforts have been made in this direction in the last two–three years since the COVID-19 pandemic started. Furthermore, the development of efficient photocatalytic nanomaterials through modifications to improve their photoactivity under ambient conditions for fighting with such a pandemic situation is a high research priority. In recent years, several metal oxides-based nano-photocatalysts have been designed to work efficiently in outdoor and indoor environments for the photocatalytic disinfection of biological species. The present review briefly discusses the advances made in the last two to three years for photocatalytic viral and bacterial disinfections. Moreover, emphasis has been given to the tailoring of such nano-photocatalysts in disinfecting surfaces, air, and water to stop viral/bacterial infection in the indoor environment. The role of such nano-photocatalysts in the photocatalytic disinfection of COVID-19 has also been highlighted with their future applicability in controlling such pandemics.