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.
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Scopus Author ID
24450001400
Researcher ID
ABA-7808-2020

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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.].

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Effect of graphene oxide on microstructure and optical properties of TiO2 thin film

2019-01-01 , Azani A. , Dewi Suriyani Che Halin , Razak K.A. , Mohd. Mustafa Al Bakri Abdullah , Mohd Salleh M.A.A. , Abdul Razak M.F.S. , Norsuria Mahmed , Ramli M.M. , Ayu Wazira Azhari , Chobpattana V.

GO/TiO2 thin films have been synthesized from titanium (IV) isopropoxide (TTIP) by a sol-gel method. The films were deposited onto a glass substrate using spin coating deposition technique then were subjected to annealed process at 350 °C. The different amount of graphene oxide (GO) was added into the parent solution of sol in order to investigate the microstructure, topography, optical band gap and photocatalytic activity of the thin films. The prepared thin films were characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), UV-VIS spectrophotometry and degradation of methylene blue (MB). AFM images reveal a rougher surface of GO/TiO2 thin film than bare TiO2 thin film due to GO particles. Moreover, the SEM images showed the formation of semispherical microstructure of bare TiO2 changes to some larger combined molecules with GO addition. The UV-Vis spectrophotometer results show that with optical direct energy gap decreases from 3.30 to 3.18 eV after GO addition due to the effect of high surface roughness and bigger grain size. Furthermore, the optical results also indicated that GO improved the optical properties of TiO2 in the visible range region.

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Mixed cations tin-germanium perovskite: A promising approach for enhanced solar cell applications

2024-04-30 , Adli Azizman M.S. , Ayu Wazira Azhari , Naimah Ibrahim , Dewi Suriyani Che Halin , Sepeai S. , Ludin N.A. , Mohammad Nuzaihan Md Nor , Ho Li Ngee

Significant progress has been made over the years to improve the stability and efficiency of rapidly evolving tin-based perovskite solar cells (PSCs). One powerful approach to enhance the performance of these PSCs is through compositional engineering techniques, specifically by incorporating a mixed cation system at the A-site and B-site structure of the tin perovskite. These approaches will pave the way for unlocking the full potential of tin-based PSCs. Therefore, in this study, a theoretical investigation of mixed A-cations (FA, MA, EA, Cs) with a tin-germanium-based PSC was presented. The crystal structure distortion and optoelectronic properties were estimated. SCAPS 1-D simulations were employed to predict the photovoltaic performance of the optimized tin-germanium material using different electron transport layers (ETLs), hole transport layers (HTLs), active layer thicknesses, and cell temperatures. Our findings reveal that EA0.5Cs0.5Sn0.5Ge0.5I3 has a nearly cubic structure (t = 0.99) and a theoretical bandgap within the maximum Shockley-Queisser limit (1.34 eV). The overall cell performance is also improved by optimizing the perovskite layer thickness to 1200 nm, and it exhibits remarkable stability as the temperature increases. The short-circuit current density (Jsc) remains consistent around 33.7 mA/cm2, and the open-circuit voltage (Voc) is well-maintained above 1 V by utilizing FTO as the conductive layer, ZnO as the ETL, Cu2O as the HTL, and Au as the metal back contact. This configuration also achieves a high fill factor ranging from 87 % to 88 %, with the highest power conversion efficiency (PCE) of 31.49 % at 293 K. This research contributes to the advancement of tin-germanium perovskite materials for a wide range of optoelectronic applications.

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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.

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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.

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The Effect of Polyethylene Glycol (PEG) on TiO2 Thin Films via Sol-Gel Method

2020-03-18 , Dewi Suriyani Che Halin , Razak K.A. , Mohamad Sukeri N.S. , Azani A. , Mohd. Mustafa Al Bakri Abdullah , Mohd Arif Anuar Mohd Salleh , Mahmed N. , Ramli M.M. , Ayu Wazira Azhari , Chobpattana V.

This research focus on the effect of polyethylene glycol (PEG) on TiO2 thin film. Sol-gel method is the best method which tends to be used due to its simplicity, good chemical homogeinity and high purity of the product. Titanium (IV) isopropoxide, isopropanol and acetic acid are the three different chemical which being used to make sol solution. The samples was then will annealed at three different temperature which are 400 °C, 500 °C and 600 °C to observed the phase composition of TiO2 added PEG thin film and pure TiO2 by using X-ray diffraction (XRD) analysis and the structural surface by using scanning electron microscope (SEM) analysis. The XRD analysis show the anatase phase present for the sample of pure TiO2 thin film and rutile phase present for the sample of TiO2 added PEG thin film. The micrograph of SEM show that with the addition of PEG at high temperature will give the analysis of flaky large cracked which is not separated to each other on the surface coating. Meanwhile, pure TiO2 give the result of irregular shape structure of the film.

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Annealing Effects on Polycrystalline Silicon Germanium (SiGe) Thin Films grown on Nanostructured Silicon Substrates using Thermal Evaporation Technique

2022-10-01 , 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.

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Synthesis of Ag-TiO2thin film - Molarity and temperature effect on Microstructure

2020-08-01 , Dewi Suriyani Che Halin , Razak K.A. , Azani A. , Mohd. Mustafa Al Bakri Abdullah , Mohd Arif Anuar Mohd Salleh , Mahmed N. , Ramli M.M. , Ayu Wazira Azhari , Chobpattana V. , Kaczmarek

Ag-TiO2thin films with different concentration of silver (Ag) added were successfully deposited onto Si-substrate via sol-gel spin coating method. The phase analysis and microstructures of Ag-TiO2thin films have been characterized by X-ray diffractometer and scanning electron microscope. X-ray diffraction spectra show existing different phases influenced by the concentration of the Ag and the annealing temperature. The micrograph of scanning electron microscopy revealed the thin films annealed at 600 °C with 7 mol% of Ag concentration which shows that the Ag particles were found like a white dot formed on the grain of TiO2thin films.

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