Norhayati Sabani
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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

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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.

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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.

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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.

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A Study on Electrical Performance of SiC-based Self-switching Diode (SSD) as a High Voltage High Power Device

2023-12-01 , Sha’ari N.Z.A.A. , Nor Farhani Zakaria , Shahrir Rizal Kasjoo , Ahmad M.F. , Mohd Natashah Norizan , Ili Salwani Mohamad , Mohd Fairus Ahmad , Shamsul Amir Abdul Rais , Banu Poobalan , Norhayati Sabani

The Self-switching Diodes (SSDs) have been primarily researched and used in low-power device applications for RF detection and harvesting applications. In this paper, we explore the potential of SSDs in high-voltage applications with the usage of Silicon Carbide (SiC) as substrate materials which offers improved efficiency and reduced energy consumption. Optimization in terms of the variation in the interface charges, metal work function, and doping concentration values has been performed by means of a 2D TCAD device simulator. The results showed that the SSD can block up to 600 V of voltage with an optimum interface charge value of 1013 cm-2, making them suitable for higher voltage applications. Furthermore, it also found that the work function of the metal contact affected the forward voltage value, impacting the current flow in the device. Variation in doping concentrations also resulted in higher breakdown voltages and significantly increased forward current, leading to an increased power rating of 27 kW. In conclusion, the usage of 4H-SiC-based SSDs shows a usable potential for high-voltage applications with optimized parameters. The results from this research can facilitate the implementation of SSD in the development of high-power semiconductor devices for various industrial applications.

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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.

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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.

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The study and preparation of polyaniline-graphene oxide as robust counter electrode for dye-sensitized solar cells

2022-05-18 , Mohd Fairul Sharin Abdul Razak , Shukor A.A. , Mohd Nazry Salleh , Nawawi W.I. , Norhayati Sabani , Badri A.

The study of alternative materials and platinum-free counter electrodes (CE) for the development of dye- sensitized solar cells (DSSC) has been highlighted nowadays. Polyaniline (PANI) is one of the most common conducting polymers applied in electrochemical energy storage and conversion technologies such as supercapacitors, rechargeable batteries and fuel cells. However, PANI counter electrodes lack long-term stability due to their low surface area and large volume changes during the release of ions. In that regard, this research work focused on the modification of protonated PANI with graphene oxide (GO) at various weight percentages (wt%) in order to obtain robust CE in DSSC. The structure and formation of PANI, GO and PANI/GO were characterized by Fourier transform infrared (FT-IR) and X-ray diffraction (XRD) analyses. The absorption spectra showed all the characteristic bands of GO, PANI(ES) and PANI/GO. Meanwhile, the incorporation of GO into PANI has enhanced the crystallinity of the composite. As a result, power conversion efficiency (PCE%) of the device with PANI/GO 3 wt% as the counter electrode reaches 6.39%. The excellent photoelectric properties, simple preparation procedure and inexpensive cost allow the PANI/GO electrode to be a credible alternative for DSSCs.

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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.

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A wearable 3D printed microfluidic device for sweat-sensing application

2024-12 , Nur Fatin Adini Ibrahim , Anas Mohd Noor , Norhayati Sabani , Shazlina Johari

This study focuses on developing a wearable microfluidic device (WMD) using stereolithography (SLA) 3D printing for sweat collection. The use of the SLA technique, particularly in achieving rapid fabrication, printing smooth surfaces, and creation of channels with dimensions below 1 mm. However, it is quite challenging to integrate the SLA 3D printed WMD with a sensor for real-time sweat analysis using a traditional bonding method. In addition, an SLA conventional resin is non-water-washable and is made from a polymer material that tends to cause a hydrophobic effect on the microchannel surface. In this work, a reversible bonding method through mechanical clamping was applied to enable easy assembly and disassembly of the WMD integrated with a sensor. A water-washable clear resin was used to provide a hydrophilic surface, allowing for effective fluid handling. The fluid delivery into the sensor's channel was efficient, taking only 0.06 s after the fluid flowed out at the outlet channel, and it sufficiently covered the entire surface of the sensor. This work also found that closed channels can be created up to 0.6 mm after fine-tuning the minimum achievable using the SLA printer. The dimensions of the printed WMD resulted in a size tolerance difference of 0.05–0.35 mm compared to the 3D model design, indicating a discrepancy of less than 1%. These capabilities promise to advance WMD and enable cutting-edge research in sweat analysis and related fields.

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The effect of solvents on the performance of organic light-emitting diodes

2020-01-08 , Ismail N.A.N. , Safizan Shaari , Juhari N. , Norhayati Sabani , Mohd Fairus Ahmad , Zakaria N.F.

In this paper, we investigate the solvent effect on the performance of surface roughness, absorption spectrum of MEH-PPV thin films and J-V characteristics for MEH-PPV OLED device. The 5 mg emissive layer of poly [2-methoxy-5(2' -ethylhexyloxy)-1, 4-phenylenevinylene), MEH-PPV was diluted with 1ml toluene and 1 ml different mixture of solvent (80% toluene+20 % chloroform) which gives the concentration of 5 mgml-1 respectively. The surface roughness of MEH-PPV film was reduced to 0.3 nm and the red-shifted maximum peak wavelength value were obtained when mixture solvent was used. However, J-V gives higher turn on voltage ∼17 V for the device used mixture solvent compared to device prepared by toluene solvent. Apparently, the two different combination of aromatic and non-aromatic solvent significantly gives an effect on thin films properties and electrical properties of MEH-PPV OLED device.

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