Nur Irwany Ahmad
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Nur Irwany Ahmad
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Ahmad, Nur Irwany
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Ahmad, Nur Irwany
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Scopus Author ID
57200991933

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Construction of calixarene-based sensor: Multilayer Langmuir–Schaefer film and first-principles studies for 4-aminobenzoic acid sensing application

2024-02-01 , Yeong Yi Wong , Faridah L Supian , Afiq Radzwan , Nur Farah Nadia Abd Karim , Farish Armani Hamidon , Nur Irwany Ahmad

Calixarenes, being well-known macrocyclic structures, have attracted considerable interest in the field of nanosensors due to their diverse advantages. 4-Aminobenzoic acid (PABA) was aimed to be detected by both calix[4]arene (C4) and calix[6]arene (C6) in this host-guest investigation. This study investigated the development of C4-PABA and C6-PABA complexes using the Langmuir–Schaefer (LS) method and first-principles density functional theory (DFT). All of the LS films formed were characterised by field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX), carbon, hydrogen, nitrogen, oxygen elemental analyser (CHNS), ultraviolet-visible spectroscopy (UV-Vis), and Fourier-transform infrared spectroscopy (FTIR). Additionally, this work applied DFT to compute the binding energy and band gap. Morphological and elemental analysis based on the conducted characterisations indicated the incorporation of PABA via lower rims into both C4 and C6. The computed binding energy and band gap validated the experiment's findings that promising reactivity existed between calixarenes and PABA with the formation of stable complexes. The sensing of PABA by both C4 and C6 was proven. In the near future, the outcomes of this research can be applied to drug delivery systems for pharmaceutical and medical purposes.

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Copper doping effect in the back surface field layer of CdTe thin film solar cells

2024-02-01 , Nur Irwany Ahmad , Kiong T.S. , Doroody C. , Rahman K.S. , Mohd Natashah Norizan , Mohd Fairus Ahmad , Kar Y.B. , Harif M.N. , Amin N.

In this work, the Solar Cell Capacitance Simulator (SCAPS-1D) is employed to evaluate the characteristics of CdTe thin films with ZnTe as the Back Surface Field (BSF) layer and estimate the effective copper doping ratio at both the atomic scale and the device operational response perspective. The electrical characteristics of ZnTe, at varying levels of copper doping, were derived using density functional theory (DFT) by applying the generalized gradient approximation (GGA) and Hubbard U corrections (DFT+U). The performance of ZnTe with different Cu concentrations as a BSF layer was evaluated by analysing the values of four key parameters that are open circuit voltage (VOC), short circuit current density (JSC), fill factor (FF), and conversion efficiency (η). The results indicate that an increase in Cu concentration from 0% to 3%, 6%, 10%, and 12% resulted in a reduction of the energy band gap. Specifically, the energy band gap decreased from 2.24 eV to 2.10 eV, 1.98 eV, 1.92 eV, and 1.88 eV, respectively. Optimal Cu doping promotes the favourable shift in the valence band maxima (VBM) and formation of p + -ZnTe, lowering thermionic emission and improving carrier lifetime, which results in an improved ohmic contact, η = 18.73% for 10% of Cu content. Excessive doping in contrast degraded the overall device performance by forming an unmatched carrier band offset at the front interface with CdS, increasing the acceptor type defect and CdTe compensation rate. Overall, the findings suggest that incorporating a controlled level of Cu, which in this case is around 10%, promotes the efficiency and stability of the proposed CdTe device configuration to a certain extent.

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A comprehensive review of flexible cadmium telluride solar cells with back surface field layer

2023-11-01 , Nur Irwany Ahmad , Kar Y.B. , Doroody C. , Kiong T.S. , Rahman K.S. , Harif M.N. , Amin N.

Recent advancements in CdTe solar cell technology have introduced the integration of flexible substrates, providing lightweight and adaptable energy solutions for various applications. Some of the notable applications of flexible solar photovoltaic technology include building integrated photovoltaic systems (BIPV), transportation, aerospace, satellites, etc. However, despite this advancement, certain issues regarding metal and p-CdTe remained unresolved. Besides, the fabrication of a full-working device on flexible glass is challenging and requires special consideration due to the unstable morphology and structural properties of deposited film on ultra-thin glass substrates. The existing gap in knowledge about the vast potential of flexible CdTe solar cells on UTG substrates and their possible applications blocks their full capacity utilization. Hence, this comprehensive review paper exclusively concentrates on the obstacles associated with the implementation of CdTe solar cells on UTG substrates with a potential back surface field (BSF) layer. The significance of this study lies in its meticulous identification and analysis of the substantial challenges associated with integrating flexible CdTe onto UTG substrates and leveraging Cu-doped ZnTe as a potential BSF layer to enhance the performance of flexible CdTe solar cells.

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Effect of Cuâ‚‚Te Back Surface Interfacial Layer on Cadmium Telluride Thin Film Solar Cell Performance from Numerical Analysis

2023-05-01 , Harif M.N. , Doroody C. , Nadzri A. , Nisham Rosly H. , Nur Irwany Ahmad , Isah M. , Amin N.

Even though substantial advances made in the device configuration of the frontal layers of the superstrate cadmium telluride (CdTe) solar cell device have contributed to conversion efficiency, unresolved challenges remain in regard to controlling the self-compensation and minority carrier recombination at the back contact that limits the efficiency. In this study, a SCAPS-1D simulator was used to analyze the loss mechanism and performance limitations due to the band-bending effect upon copper chloride treatment and subsequent Cu2Te layer formation as the back contact buffer layer. The optimal energy bandgap range for the proposed back surface layer of Cu2Te is derived to be in the range of 1.1 eV to 1.3 eV for the maximum conversion efficiency, i.e., around 21.3%. Moreover, the impacts of absorber layer’s carrier concentration with respect to CdTe film thickness, bandgap, and operational temperature are analyzed. The optimized design reveals that the acceptor concentration contributes significantly to the performance of the CdTe devices, including spectral response. Consequently, the optimized thickness of the CdTe absorber layer with a Cu-based back contact is found to be 2.5 µm. Moreover, the effect of temperature ranging from 30 °C to 100 °C as the operating condition of the CdTe thin-film solar cells is addressed, which demonstrates an increasing recombination tread once the device temperature exceeds 60 °C, thus affecting the stability of the solar cells.

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Determination of soft starter firing angle performance to mitigate motor high inrush current using current limitation method

2020-03-20 , Mohamad Shukor Abdul Rahim , Azizan, Muhammad Mokhzaini , Mohd Irwan Yusoff , Mohd Hafizuddin Mat , Nur Irwany Ahmad , Noor Fazliana Fadzail , Md Esa, Suhaireza Binti

Inrush current in the simplest form can also be determined as current drawn by an induction motor during startup period. This starting current will shoot up about 5 to 7 times the rated current. However, this high current usually occur in the starting period only. To overcome this, several techniques can be implemented to reduce the high current. The configuration of soft starter just involving some power semiconductor device act as switches that control the current flow from power source to the motor. The switches is in form of thyristor and are connected back-to-back because the system conduct in AC system. The current output can be controlled by varying the firing angle. This changing of firing angle will be managed by a firing angle control circuit. This soft starter was connected between power source and motor. The thyristors that built in soft starter act like a gate to control the voltage applied to the motor. The firing angle for current limitation soft starter was changed to several angle and what can be concluded that the high current succeed to mitigate with increasing the firing angle. The current drawn for this type of starter is steadily constant. The lower current during starting took longer time for motor to reach its rated speed. This type of starter successfully reduces inrush current about 42 percent. Finally what can be concluded is that the soft starter was proven to mitigate inrush current. Type of soft starter that going to implement is depending on the application of motor. When the application need to control the torque is more suitable to use current limitation soft starter because the current is steadily control.

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Performance Analysis of Unipolar SPWM Inverter: Resistive load and Inductive load

2020-12-18 , Muhammad Zaid Aihsan , Ahmad Muhyiddin Yusof , Nur Irwany Ahmad , Mohd Saifizi Saidon , Habibah Mokhtaruddin , Diyya Hidayah Abdul Rahman , Wan Azani Wan Mustafa

This paper presents the performance analysis of the Unipolar SPWM Inverter for the resistive and inductive load testing. The common criteria reported in various technical papers where the resistive load will produce a unity power factor correction and lagging power factor behaviour for inductive load. This paper is to demonstrate the performance of both loads that are tested to the single phase Unipolar SPWM inverter under the modulation ratio of 0.8. The performances will be covered in term of the waveform behavior and THDv performance. The project are carried out through the simulation using PSIM software and real implementation to the real hardware. The selection of filter for this paper is the low pass passive LC filter.

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