Ayu Wazira Azhari
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Preferred name
Ayu Wazira Azhari
Official Name
Ayu Wazira, Azhari
Alternative Name
Ayu, A. W.
Azhari, Ayu W.
Main Affiliation
Scopus Author ID
24450001400
Researcher ID
ABA-7808-2020

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Now showing 1 - 10 of 21
  • Publication
    Annealing effects on Polycrystalline Silicon Germanium (SiGe) thin films grown on nanostructured silicon substrates using thermal evaporation technique
    (Universiti Malaysia Perlis (UniMAP), 2022-10)
    Ayu Wazira Azhari
    ;
    Eop, T. S.
    ;
    Dewi Suriyani Che Halin
    ;
    Uda Hashim
    ;
    Sopian, K.
    ;
    Zaidi, S. H.
    Polycrystalline SiGe thin films have been formed after thermal annealing of formerly vacuum evaporated a-Ge layers. The a-Ge thin films were deposited onto nanostructured Si substrates via low-cost thermal evaporation method. Then, the films were annealed in a furnace at temperatures ranging from 400 °C to 1000 °C resulting in crystal growth of the SiGe layers. In general, the annealing temperature for polycrystalline SiGe is between 600 °C – 800 °C. The crystalline structure of the SiGe layer is improved as a function of increased temperature. This is shown by the low FWHM of about 5.27 as compared to the commercially available Ge substrates where the FWHM value is about 5.06. This method also produces more relax Ge layer where the strain value is 0.261.
  • Publication
    Effect of polyethylene glycol and sodium dodecyl sulphate on microstructure and self-cleaning properties of graphene oxide/TiO2 thin film
    ( 2020-09-01)
    Azani A.
    ;
    Dewi Suriyani Che Halin
    ;
    Kamrosni Abdul Razak
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Norsuria Mahmed
    ;
    Muhammad Mahyiddin Ramli
    ;
    Mohd Arif Anuar Mohd Salleh
    ;
    Mohd Fairul Sharin Abdul Razak
    ;
    Ayu Wazira Azhari
    ;
    Chobpattana V.
    ;
    Kaczmarek L.
    In this study, a sol gel procedure for preparation of TiO2 thin films with graphene oxide (GO) was developed. The effect of PEG and SDS addition on the microstructure of the films as well as the photocatalytic activity of the thin film was also investigated. The morphology and surface structure of the films were studied by SEM and AFM while the photocatalytic activity of the films was analyzed by measuring the degradation of methylene blue under sunlight irradiation using UV-Vis spectrophotometer. It was found that GO/TiO2 thin film with PEG shows a smaller and porous particle while GO/TiO2 thin film with SDS formed a very smooth surface and very fine particles. Therefore, in AFM analysis reveals that surface roughness decreases with the addition of PEG and SDS. Finally, the photocatalytic activity showed that GO/TiO2 thin film with SDS have the most effective self-cleaning property which degrade 64% of methylene blue that act as model of contaminants.
      1
  • Publication
    Microplastics in facial cleanser: extraction, identification, potential toxicity, and continuous-flow removal using agricultural waste–based biochar
    ( 2023-05-01)
    Hanif M.A.
    ;
    Naimah Ibrahim
    ;
    Farrah Aini Dahalan
    ;
    Umi Fazara Md Ali
    ;
    Masitah Hasan
    ;
    Ayu Wazira Azhari
    ;
    Jalil A.A.
    Microplastic (MP) is an emerging contaminant of concern due to its ubiquitous quantity in the environment, small size, and potential toxicity due to strong affinity towards other contaminants. In this work, MP particles (5–300 μm) were extracted from a commercial facial cleanser and determined to be irregular polyethylene (PE) microbeads based on characterization with field emission scanning electron microscopy (FESEM) and Raman spectroscopy. The potential of extracted MP acting as toxic pollutants’ vector was analyzed via adsorption of methylene blue and methyl orange dye where significant dye uptake was observed. Synthetic wastewater containing the extracted MP was subjected to a continuous-flow column study using palm kernel shell and coconut shell biochar as the filter/adsorbent media. The prepared biochar was characterized via proximate and ultimate analysis, FESEM, contact angle measurement, atomic force microscopy (AFM), and Fourier transform infrared (FTIR) spectroscopy to investigate the role of the biochar properties in MP removal. MP removal performance was determined by measuring the turbidity and weighing the dry mass of particles remaining in the effluent following treatment. Promising results were obtained from the study with highest removal of MP (96.65%) attained through palm kernel shell biochar with particle size of 0.6–1.18 mm and continuous-flow column size of 20 mm. Graphical abstract: [Figure not available: see fulltext.].
      7  30
  • Publication
    Microstructure evolution of Ag/TiOâ‚‚ thin film
    ( 2021)
    Dewi Suriyani Che Halin
    ;
    Kamrosni Abdul Razak
    ;
    Mohd Arif Anuar Mohd Salleh
    ;
    Mohd Izrul Izwan Ramli
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Ayu Wazira Azhari
    ;
    Kazuhiro Nogita
    ;
    Hideyuki Yasuda
    ;
    Marcin Nabiałek
    ;
    Jerzy J. Wysłocki
    Ag/TiO₂ thin films were prepared using the sol-gel spin coating method. The microstructural growth behaviors of the prepared Ag/TiO₂ thin films were elucidated using real-time synchrotron radiation imaging, its structure was determined using grazing incidence X-ray diffraction (GIXRD), its morphology was imaged using the field emission scanning electron microscopy (FESEM), and its surface topography was examined using the atomic force microscope (AFM) in contact mode. The cubical shape was detected and identified as Ag, while the anatase, TiO₂ thin film resembled a porous ring-like structure. It was found that each ring that coalesced and formed channels occurred at a low annealing temperature of 280 °C. The energy dispersive X-ray (EDX) result revealed a small amount of Ag presence in the Ag/TiO₂ thin films. From the in-situ synchrotron radiation imaging, it was observed that as the annealing time increased, the growth of Ag/TiO₂ also increased in terms of area and the number of junctions. The growth rate of Ag/TiO₂ at 600 s was 47.26 µm2/s, and after 1200 s it decreased to 11.50 µm2/s and 11.55 µm2/s at 1800 s. Prolonged annealing will further decrease the growth rate to 5.94 µm2/s, 4.12 µm2/s and 4.86 µm2/s at 2400 s, 3000 s and 3600 s, respectively.
      3  17
  • Publication
    Annealing effects on polycrystalline silicon germanium (SiGe) thin films grown on nanostructured silicon substrates using thermal evaporation technique
    ( 2022-10)
    Ayu Wazira Azhari
    ;
    Eop, T. S.
    ;
    Dewi Suriyani Che Halin
    ;
    Sopian, K.
    ;
    Uda Hashim
    ;
    Zaidi, S. H.
    Polycrystalline SiGe thin films have been formed after thermal annealing of formerly vacuum evaporated a-Ge layers. The a-Ge thin films were deposited onto nanostructured Si substrates via low-cost thermal evaporation method. Then, the films were annealed in a furnace at temperatures ranging from 400 °C to 1000 °C resulting in crystal growth of the SiGe layers. In general, the annealing temperature for polycrystalline SiGe is between 600 °C – 800 °C. The crystalline structure of the SiGe layer is improved as a function of increased temperature. This is shown by the low FWHM of about 5.27 as compared to the commercially available Ge substrates where the FWHM value is about 5.06. This method also produces more relax Ge layer where the strain value is 0.261.
      1  14
  • Publication
    Metal induced crystallization of polycrystalline silicon germanium: The morphological study between nickel and copper
    (AIP Publishing Ltd., 2023)
    T. S. Eop
    ;
    Ayu Wazira Azhari
    ;
    L. Mohamad Jazi
    ;
    K. S. Ting
    ;
    Dewi Suriyani Che Halin
    ;
    Abdul Kareem Thottoli
    In this study, metal induced crystallization technique is used in to obtain the lower temperature point in crystallization. Two different metals with one non-metal configuration as a baseline i.e. SiGe/Ni, SiGe/Cu and SiGe. A simple metal-assisted chemical etching method is used to fabricate the Si nanopillar, with Ag acting as a catalyst. Following by deposition of metal namely nickel (Ni) and copper (Cu) then undergo thermal annealing from 200 ℃ until 1000 ℃ to improve the crystallinity of the Ge layer. Morphological studies of surface area were conducted using scanning electron microscopy (SEM). The results show that the crystallization temperature of SiGe with Ni was obtained at 400 ℃ while the crystallization temperature of SiGe without any metal was obtained at 600 ℃. Meanwhile the crystallinity, for SiGe/Cu only occurs in very low level where the structure did not change until the annealing was conducted at 600 ℃. Based from these result, it is proved that the metal can help lowering the crystallization temperature and improving the defects of SiGe.
      12  1
  • Publication
    Exploring the potential of metal oxides as cathodic catalysts in a double chambered microbial fuel cell for phenol removal and power generation
    ( 2023-07-01)
    Yap K.L.
    ;
    Ho Li Ngee
    ;
    Guo K.
    ;
    Liew Yun Ming
    ;
    Nabilah Aminah Lutpi
    ;
    Ayu Wazira Azhari
    ;
    Thor S.H.
    ;
    Teoh T.P.
    ;
    Oon Y.S.
    ;
    Ong Soon An
    Detection of high phenol concentrations in industrial wastewater contributed to the need for more efficient wastewater treatment approaches. This study compared and investigated the different metal oxides as cathodic catalysts in a double chambered microbial fuel cell (MFC) for simultaneous phenol removal and bioelectricity generation. Metal oxides such as copper (II) oxide (CuO), manganese dioxide (MnO2) and tin (IV) oxide (SnO2) were synthesized and loaded on a carbon (C) plate, respectively, for application as cathode in the MFC. Results revealed that total chemical oxygen demand and phenol removal efficiency of MFC depleted in the order of CuO/C (96.69 and 100 %) > β-MnO2/C (90.93 and 94.41 %) > α-MnO2/C (84.69 and 90.17 %) > SnO2/C (80.25 and 84.84 %) > bare C (70.48 and 77.06 %) cathode due to the deterioration in the oxygen reduction reaction reactivity. Besides, the solution pH was crucial in determining the catalyst's surface charge properties. At pH 8, higher solution conductivity and stronger electrostatic attraction between positively charged CuO and anionic phenol molecules were favourable for the complete phenol removal. This phenomenon contributed to a 1.77-fold higher maximum power density attained at pH 8 (29.24 mW m−2) than that of pH 11 (16.52 mW m−2) due to more electrons could be utilized for electricity generation. This study provided valuable information on the facile fabrication of cost-effective cathodic catalysts in a double chambered MFC for wastewater treatment and bioelectricity generation.
      3  14
  • Publication
    Numerical simulation of lead-free tin and germanium based all perovskite tandem solar cell
    ( 2023-12)
    Rae-Ann Lim Jia En
    ;
    Ayu Wazira Azhari
    ;
    Dewi Suriyani Che Halin
    ;
    Suhaila Sepeai
    ;
    Norasikin Ahmad Ludin
    The ability to customize the materials bandgaps makes perovskite solar cells a promising candidate for hybrid-tandem applications. This allows them to effectively utilize parts of the solar spectrum that silicon-based solar cells cannot efficiently capture, resulting in higher absorption coefficients. However, there is a lack of research on lead-free all-perovskite tandem solar cells, and secondary data on materials is limited. One of the main challenges in previous studies is the high cost and solid structure of traditional silicon-based solar cells, which require significant storage space. Additionally, lead-based perovskite solar cells pose environmental concerns due to their water solubility and potential harmful effects upon consumption. To address these issues, thin-film perovskite solar cells with liquid solvents are employed in the solar cell design. Lead is replaced with germanium and tin-based perovskites, which exhibit comparable photovoltaic performance to silicon. In the present work, the OghmaNano simulation tool was utilized to conduct numerical simulation of the perovskite design. The perovskite solar cell layers were structured as follows: FTO/ZnO/MAGeI3/Spiro-OMeTAD/FAMASnGeI3/Cu2O/Au. The variables considered included optimum layer thicknesses and bandgaps, as well as the most suitable materials for the ETL and HTL, aiming to obtain the highest efficiency. Based on the simulation results, the proposed perovskite structure shows remarkable photovoltaic parameters. The Voc was measured at 0.84 V Jsc of 16.1 mA/cm2, FF of 0.825, and PCE that reached 11.12%. This project contributes to future research on materials for the ETL and HTL of lead-free, tin and germanium based APTSCs.
      1  2
  • Publication
    A Study on the Environmental Impact During Distribution and Disposal Stages for the 3-Ply Face Masks by Using Life Cycle Assessment (LCA)
    ( 2022-01-01)
    Chow Suet Mun Christine
    ;
    Tengku Nuraiti Tengku Izhar
    ;
    Irnis Azura Zakaria
    ;
    Sara Yasina Yusuf
    ;
    Ayu Wazira Azhari
    ;
    Boboc M.
    The demand of face masks had increased tremendously due to pandemic outbreak of COVID-19, leading to the increment production rate of face masks in Malaysia. Waste is also produced at the same time, resulting impacts towards the environment. Due to the land scarcity issue in Malaysia, the end of life treatment for the waste is taken into consideration. The study tools used in this study is life cycle assessment (LCA) to identify the significant potential environmental impact produced during the life cycle stages for distribution and disposal through GaBi Education Software. The disposal stage between landfill and incineration of the 3-Ply face masks is studied to determine the end of life treatment for it. The impact assessment method selected in this study is CML 2001-Jan 2016 with the environmental indicator of Global Warming Potential (GWP), Acidification Potential (AP), Eutrophication Potential (EP) and Ozone Depletion Potential (ODP). GWP results in producing highest impact to the environment during both distribution and disposal stages. The impact of GWP also relates to the climate change. Modern incineration is recommended to overcome the issue of land scarcity in Malaysia as the amount of waste by 3-Ply face masks are increasing due to the pandemic COVID-19, reducing the impacts towards the environment.
      33  1
  • Publication
    Progress in tin-germanium perovskite solar cells: A review
    ( 2023-11-01)
    Azizman M.S.A.
    ;
    Ayu Wazira Azhari
    ;
    Dewi Suriyani Che Halin
    ;
    Ibrahim N.
    ;
    Sepeai S.
    ;
    Ludin N.A.
    ;
    Nor M.N.M.
    ;
    Ho L.N.
    The primary cause for concern in developing perovskite solar cells (PSCs) is the potential environmental repercussions of employing lead (Pb) as the absorber. The majority of studies hypothesised that the use of tin-based perovskite could be the key to creating environmentally and financially viable PSCs. This is because tin (Sn) and lead (Pb) are both elements in group 14 of the periodic table. Perovskite materials based on tin and lead also have nearly ideal direct band gaps, which range from 1.23 eV to 1.30 eV. Nonetheless, major challenges that may suppress the potential of Sn-based PSCs include the stability issue with low formation energy, high carrier density, and easily oxidised from Sn2+ to Sn4+ upon exposure to air. These limitations are anticipated to be vital impediments to creating a stable and effective Sn-based perovskite. Recent advances have shown that alloying with germanium (Ge) is one of the approaches to overcome stability issues and thus improve the overall efficiency of the PSCs. However, the stability and efficiency of these Ge-based PSCs are still unable to surpass those of Pb-based devices. This review covers the research interest in SnGe PSCs from the initial study to the current year by focusing on the methodology used and significant results. The output is believed to be useful in developing Pb-free PSCs using SnGe-based materials.
      2  2