Norhayati Sabani
Thumbnail Image
Preferred name
Norhayati Sabani
Official Name
Norhayati, Sabani
Alternative Name
Sabani, N.
Sabani, Norhayati
Sabani, Norhayati Bt
Norhayati, S.
Sabani, Norhayati Binti
Main Affiliation
Scopus Author ID
54785178400
Researcher ID
AAB-8243-2022

Research Output

Filters

9 5
40
Reset filters

Settings
Now showing 1 - 10 of 40
  • Publication
    Electrochemiluminescence of carbon dots and nitrogen-doped carbon dots from a microwave-assisted method
    ( 2023-10)
    Nurul Izzati Akmal Mohd Azman
    ;
    Muhammad Amirul Afiq Abdul Halim
    ;
    Nur Syakimah Ismail
    ;
    Nur Hamidah Abdul Halim
    ;
    Nurjuliana Juhari
    ;
    Norhayati Sabani
    ;
    Siti Aisyah Shamsudin
    ;
    Eiichi Tamiya
    This research focuses on the use of carbon dots (CDs) and nitrogen-doped carbon dots (NCDs) synthesized using a microwave-assisted method as electrochemiluminescence (ECL) luminophores. CDs have been synthesized using citric acid, while various concentrations of nitrogen-doped CDs have been successfully obtained by varying the amount of urea from 1 to 3 g with citric acid to produce NCD1, NCD,2 and NCD3. The ECL mechanism of CDs and NCDs on screen-printed electrodes has been studied using cyclic voltammetry (CV). ECL emission from as-prepared CDs and NCDs was observed in PBS with potassium persulfate (K2S2O8) as a co-reactant. The addition of potassium chloride (KCl) as a supporting electrolyte displays fast electroreduction of CDs and K2S2O8 to expedite the generation of CDs and peroxydisulfate radicals that simultaneously increase ECL intensity. Furthermore, as the concentration of nitrogen-doped CDs increases, so does the intensity of the ECL. NCD3 shows the highest ECL intensity by an increment of 86.4% in comparison to CDs in PBS with the addition of K2S2O8 and KCl. Finally, optimization of ECL measurement was carried out in terms of CV potential range, concentration of luminophore, supporting electrolyte, and co-reactant using NCD3 luminophore. The CV potential range at 0 to -2 V shows 50 mV of early CV reverse onset potential that resulted in an increase of 52.9% ECL intensity. Meanwhile, 30x dilution of NCD3, 0.1 M of supporting electrolyte KCl, and 0.1 M of co-reactant K2S2O8 show the optimum value to obtain high ECL intensity.
  • Publication
    Solvent Effect on the Electrical and Structural Properties for MEH-PPV Organic Light Emitting Diodes (OLED)
    ( 2021-03-01)
    Ismail N.A.N.
    ;
    Safizan Shaari
    ;
    Juhari N.
    ;
    Norhayati Sabani
    ;
    Ahmad M.F.
    ;
    Zakaria N.F.
    In this paper, the performance of the electrical properties (J-V) and surface roughness of MEH-PPV based organic light-emitting diodes (OLED) towards solvent effect was investigated. The MEH-PPV layer was deposited using spin coating technique at fixed spun speed of 3000 rpm. Two different solvents, toluene and chloroform (CHCl3) and mixture toluene:CHCl3 with the ratio of 4:1 and 1:4 were used to dilute MEH-PPV at fixed concentration of 5 mgml-1. Apparently, the mixture of solvent makes the surface roughness of the MEH-PPV films reduced to 0.15 nm and 3.59 nm under the ratio 4:1 and 1:4 respectively. Besides, the mixture solvents makes the value of turn on voltage was dropped to ∼7.2 V and ∼9 V respectively compared to non-mixture solvent. The combination of different solvent apparently gives an effect on the electrical and structural properties of organic light-emitting diode.
  • Publication
    Modification of photoanode surface structure via image analysis on organic polymer material based for dye-sensitized solar cell (DSSC) applications
    ( 2021-12)
    N. Rosli
    ;
    Norhayati Sabani
    ;
    MF Ahmad
    ;
    Mohd. Azarulsani Md. Azidin
    ;
    Nurjuliana Juhari
    ;
    NF Zakaria
    ;
    Mohd Natashah Norizan
    ;
    Safizan Shaari
    In this study, the experiment on the modification of the photoanode with organic polymer material as copolymer template for dye-sensitized solar cell (DSSC) applications has been conducted. The two organic copolymer templates are polystyrene sphere (PS) and poly[2- methoxy-5(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV). The modification photoanodes were made using Dr. Blade’s method. These organic copolymer templates were added to improve the surface of the mesoporous titanium dioxide (TiO₂) layer, which is used as the main component in DSSC photoanode. The unmodified TiO₂ photoanode has poor aggregation and porosity of TiO₂. The addition of either MEH-PPV or PS sphere to the photoanode layer was found to affect the surface of mesoporous TiO₂ in terms of porosity, particle size distribution and shape. The analysis of the TiO2 modification was conducted using an image analysis processing method via a 2D scanning electron microscope (SEM) image. The image analysis processing method used was the ImageJ program. The DSSC of modified photoanode is fabricated using metal complex dye, Ruthenium (N719) dye. The data collected from the ImageJ program showed that by adding organic copolymer templates into TiO₂, the porosity of TiO₂ decreased from 45 % to 42 %. From the photovoltaic analysis obtained, the J-V characteristic is recorded with the photoanode of TiO₂ mixed with 1.00 wt% MEH-PPV gave the highest efficiency, which is 0.01 % with the following parameters – Voc = 0.43 V, Jsc = 0.17 mA/cm2 and FF = 0.20. Meanwhile, the photoanode of TiO₂ mixed with 0.50 wt% PS sphere gave the highest efficiency which is 0.08 % with the following parameters – Voc = 0.39 V, Jsc = 0.86 mA/cm2 and FF = 0.25.
  • Publication
    Dyes extracted from Hibiscus Sabdariffa flower and Pandannus amaryllifolius leaf as natural dye sensitizer by using an alcohol-based solvent
    ( 2021-03-01)
    Rosli N.
    ;
    Norhayati Sabani
    ;
    Shahimin M.M.
    ;
    Nurjuliana Juhari
    ;
    Shaari S.
    ;
    Ahmad M.F.
    ;
    Zakaria N.
    The efficiency improvement of Dye sensitized solar cells (DSSC), the fabrication of DSSC by using metal-free organic natural dyes with a different type of solvents for the extraction of dye sensitizer was investigated. The metal-free organic Dye which comes from anthocyanin and chlorophyll dyes were dissolved by using different solvents, which are ethanol, methanol and mixture of ethanol and methanol. Anthocyanin dye was extracted from the petals of Hibiscus Sabdariffa (Roselle), and chlorophyll dye was extracted from the epidermal leaves of Pandannus amaryllifolius (Pandan). The purpose of using different solvents from alcohol-based was to determine which solvents that produce the highest effect in term of efficiency for DSSC. To confirm which solvents that produce the highest efficiency to the DSSC, the photovoltaic measurement was conducted, and the data was collected. From the photovoltaic analysis, the J-V characteristics under illumination are recorded. The sample that used anthocyanin dye extracted from Roselle flower diluted with methanol solvent gave the highest efficiency which is 0.0005% with the following parameters-Voc = 0.419 V, Jsc = 0.0057 mA/cm2 and FF = 0.24. Meanwhile, the sample that used chlorophyll dye extracted from Pandan leaves diluted with a mix of ethanol and methanol solvents gave the highest efficiency which is 0.00014% with the following parameters-Voc = 0.347 V, Jsc = 0.0016 mA/cm2 and FF = 0.25.
  • Publication
    Impact of buried oxide thickness in substrate-gate integrated silicon nanowire field-effect transistor biosensor performance for charge sensing
    ( 2021-07-21)
    Tan Y.M.
    ;
    Mohamad Faris Mohamad Fathil
    ;
    Mohammad Nuzaihan Md Nor
    ;
    Norhayati Sabani
    ;
    Teoh X.Y.
    ;
    Mohd Khairuddin Md Arshad
    ;
    Subash Chandra Bose Gopinath
    ;
    Rahman S.F.A.
    ;
    Uda Hashim
    The paper investigated on performance in charge sensing for substrate-gate integrated silicon nanowire field-effect transistor biosensor at different thickness of the buried oxide layer, sandwiched in between the top-silicon and substrate layers. The device structures with different buried oxide thickness ranging from 100 to 200 nm were designed and simulated using the Silvaco ATLAS device simulation software. The increase of buried oxide thickness reduced the strength of induced electric field that contributes to the formation of inversion layer for current flow through the silicon nanowire channel, hence contributed to the increase in threshold voltage. For simulation of charge sensing, the device demonstrated the ability to identify different interface charge values ranging from -5×1010 to -9×1010 e· cm-2 applied on the surface of the silicon nanowire channel to represent target charge biomolecules that bound to the biosensor in actual detection. Significant change in threshold voltage can be observed due to the applied interface charge density values and was evaluated to determine the sensitivity for charge sensing performance. The device shows better performance when designed with buried oxide thickness of 200 nm at sensitivity of 1.151 V/e· cm-2.
  • Publication
    Optimization of MEH-PPV based single and double-layer TOLED structure by numerical simulation
    ( 2021-12)
    T. Kersenan
    ;
    Nor Farhani Zakaria
    ;
    Safizan Shaari
    ;
    Norhayati Sabani
    ;
    Nurjuliana Juhari
    ;
    Meor Ahmad Faris bin Meor Ahmad Tajudin
    ;
    A.F.A Rahim
    In this work, we simulated and characterized Poly [2-methoxy-5-(2’-ethylhexyloxy)-1, 4-phenylene vinylene] (MEH-PPV) based single and double-layer TOLED by using Silvaco ATLAS device simulator to achieve prominent values of electrical and optical properties of the device. MEH-PPV were used as the emitting layer (EML) in the single-layer, while addition of Poly [(3,4-ethylene dioxythiophene)-poly(styrene sulfonate)] (PEDOT-PSS) as the electron transport layer (ETL) were conducted in double-layer TOLED simulation. The EML and ETL thickness in both structures were varied between 10 – 150 nm, respectively, to observe and understand the underlying physics of the relation in the layer thickness to the electrical and optical characteristics. Furthermore, variation of the EML/ETL thickness ratio from 1:1 to 5:1 (with thickness in between 10 to 50 nm) had also been conducted. From this work, it is understood that the thickness of the EML layer plays the most important role in TOLED, and by balancing the carrier injections and recombination rate in appropriate EML/ETL thickness ratio, the electrical and optical properties can be improved. By optimizing the EML/ETL thickness and thickness ratio, an optimal forward current of 1.41 mA and luminescent power of 1.93e-18 W/μm has been achieved with both MEH-PPV and PEDOT-PSS layer thickness of 10 nm (1:1 ratio), respectively. The results from this work will assist the improvement of TOLED device to be implemented widely in low power and transparent electronic appliances.
  • Publication
    The efficiency effect of dye sensitized solar cell using different ratio of organic polymer doped titanium dioxide at different annealing process temperature
    ( 2020-01-08)
    Norhisamudin N.A.
    ;
    Norhayati Sabani
    ;
    Rosli N.
    ;
    Mohd Fairus Ahmad
    ;
    Juhari N.
    ;
    Safizan Shaari
    ;
    Zakaria N.
    Titanium Dioxide (TiO2) is one of the main materials in Dye Sensitized Solar Cell (DSSC). It is well known with its property of good optical transmittance and its mesoporous surface that can absorb generous amount of dye. In this study, TiO2 is fabricated using spin coating technique that leads to the uniform thickness of TiO2 layer. The thickness of the TiO2 can be controlled layer by layer using same technique to get an optimized surface that can lead to better performance of DSSC. In order to achieve this, the surface roughness of TiO2 must be as high as possible. Therefore, the organic material which is Poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene-vinylene (MEH-PPV) is used as medium to increase the mesoporous roughness structure of TiO2 nanocrystal film for DSSC. MEH-PPV is doped into the TiO2 using 0.5 mg/ml with different temperatures of 100°C and 450°C. Different temperatures of MEH-PPV will lead to the different surface structures for TiO2 thin film. The ratio of TiO2:MEH-PPV used were 1:1 and 2:1. The surface of TiO2 thin film was characterized using Atomic Force Microscope (AFM). The efficiency was obtained using Solar Simulator based on the voltage and current flow. Based on the results, the increment of surface roughness is about 21% for the different ratio at various temperatures. The optimum temperature and suitable ratio of TiO2:MEH-PPV was obtained via annealing process at 450°C with the ratio of 2:1. It gives the highest efficiency which is 0.1266%. These two important findings yield good mesoporous surface of TiO2 thin film.
  • Publication
    Fabrication of Graphene Electrode via Graphene Transfer Method for Bisphenol A (BPA) Detection
    ( 2021-01-01)
    Shukri N.I.B.A.
    ;
    Norhayati Sabani
    ;
    Ruslinda A. Rahim
    ;
    Mohamad Faris Mohamad Fathil
    ;
    Syarifah Norfaezah Sabki
    ;
    Nur Hamidah Abdul Halim
    ;
    Nur Syakimah Ismail
    Exposure of BPA is a concern as BPA can seep into food or beverages from containers and can possibly effects on human health especially endocrine systems. An electrochemical-based aptasensor utilizing graphene was developed in detecting endocrine disrupting compound Bisphenol A (BPA, 4,4'-(propane-2,2-diyl) diphenol). The graphene modified electrode was developed via graphene transfer. Fabrication and characterization of graphene transfer was studied in this paper using Scanning Electron Microscopy (SEM) and High-Power Microscope (HPM). In this research, the investigation of interfacial characteristic modified graphene with aptasensor and recognition of BPA with aptasensor had been done using electrochemical impedance spectroscopy (EIS). The increment of charge transfer resistance (Rct) before and after recognition of BPA denoting the accumulation of charge at the electrode surface in this research.
  • Publication
    Taguchi method statistical analysis on characterization and optimization of 18-nm double gate MOSFETs
    ( 2024-10)
    A.H Afifah Maheran
    ;
    M. Pritigavane
    ;
    N.H.N.M. Nizam
    ;
    F. Salehuddin
    ;
    Norhayati Sabani
    A bi-layer graphene with a multigate structure was intensified and analysed on an 18-nm Metal Oxide Semiconductor Field-Effect Transistor (MOSFET) device to obtain an optimal performance parameter. The device has a gate structure made of Titanium Dioxide (TiO2) that serves as a high-k material and a metal gate made of Tungsten Silicide (WSix). The Silvaco TCAD Software which are ATHENA and ATLAS modules were used to enhance the fabrication process of virtual devices and to verify the electrical properties of a specific device. According to the International Technology Roadmap Semiconductor (ITRS) specifications of 0.179 V ± 12.7% for threshold voltage (VTH) and 20 nA/m for leakage current (ILEAK), the Taguchi L9 orthogonal array strategy was used to improve the device process parameters for optimum VTH and ILEAK. For the NMOS device, the process parameter of VTH Adjust Implant Dose was used as the dominant factor while Source/Drain (S/D) Implant Energy was used as the adjustment factor whereby for PMOS device, S/D Implant Energy was the dominant factor while S/D Implant Tilt was the adjustment factor in order to achieve a robust design through the Taguchi method implementation. The percentage affecting the process parameter is then applied to the results of the signal to noise ratio (SNR) of Nominal-the-best (NTB) for VTH and Smaller-the-better (STB) for ILEAK.
  • Publication
    Remazol orange dye sensitized solar cell using graphene oxide and reduced graphene oxide working electrode
    (Universiti Malaysia Perlis (UniMAP), 2018-12)
    Norhayati Sabani
    ;
    Siti S. Mat isa
    ;
    Muhammad Mahyiddin Ramli
    ;
    N. Rosli
    Dye Sensitized Solar Cell (DSSC) is said as a potential solar device which offers easy, cheaper and greener materials and preparation process. However, the efficiency of this device is still an ultimate problem and challenge. In this paper, an organic Remazol orange dye was used as the DSSC dye sensitizer which prepared with different working electrodes. The different working electrodes consist of Titanium Dioxide (TiO2) with Graphene Oxide (GO) and TiO2 with reduced Graphene Oxide (rGO). In order to analyze the adsorption characteristics of GO and rGO, the solution was tested using Ultraviolet-Visible-Near Infrared Spectrophotometry and the surface morphology of all mixed pastes was observed under Atomic Force Microscopy and Scanning Electron Microscope. Then, the device performance was tested under illumination of solar cell simulator. From overall results, the efficiency for all tested devices was quite low from expectation. For this work, the performance of TiO2-rGO DSSC at 0.138% is 84.7% higher compared to the TiO2-GO DSSC which was 0.021%. This result was obtained when the working electrode and dye less exposed to the light during dye preparation process at 24 hours soaking time.