Nurjuliana Juhari
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Nurjuliana Juhari
Official Name
Nurjuliana, Juhari
Alternative Name
Juhari, Nurjuliana Binti
Juhari, Nurjuliana
Juhari, N.
Juhari, N. J.
Main Affiliation
Scopus Author ID
22634152000
Researcher ID
CWQ-4839-2022

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  • Publication
    The Effect of Different Solvents in Natural Dyes from Roselle (Hibiscus Sabdariffa) and Green Tea Leaves (Camellia Sinensis) for Dye-Sensitized Solar Cell
    ( 2021-03-01)
    Norhisamudin N.A.
    ;
    Norhayati Sabani
    ;
    Shamimin M.M.
    ;
    Nurjuliana Juhari
    ;
    Shaari S.
    ;
    Ahmad M.F.
    ;
    Zakaria N.
    A dye-sensitized solar cell (DSSC) fabricated using anthocyanin or chlorophyll natural dye extract coming from Roselle (Hibiscus Sabdariffa) and Green Tea leaves (Camellia Sinensis). Both dye pigmentations were extracted using different alcohol-based solvent, namely, ethanol, methanol and mixed (ethanol + methanol) to identify whether the different solvents give the effect during the dye extraction. The performance of the electron transfer interaction between the natural dye and Titanium Dioxide (TiO2) was determined. The photovoltaic response of DSSC was collected by recording the data of I-V characteristic under illumination. The DSSC using the Roselle dye extract yielded the following results; Voc = 0.001 V, Jsc = 0.00868(mA/cm2), FF = 0.3554 and η = 0.00142% which is coming from the mixed solvent. On the other hand, the green tea dye extract yielded the following results; Voc = 0.3985, Jsc = 0.000797 (mA/cm2), FF = 0.3985 and η = 0.0000752% which is coming from the methanol solvent.
  • Publication
    Analysis of Power Distribution in Mach Zehnder Interferometer Polymer-based Waveguide for Sensing Applications
    ( 2022-12-01)
    Mohd. Azarulsani Md. Azidin
    ;
    Nurjuliana Juhari
    ;
    Arif Mawardi Ismail
    ;
    Norhayati Sabani
    Two Mach Zehnder Interferometer (MZI) polymer-based waveguide designs namely MZI symmetrical and MZI asymmetrical structures were simulated and analyzed using Optiwave OptiBPM10. The two designs with device size of 4000μm x 300μm exhibit clear optical propagation path when light is simulated through them as well as displaying single mode profile. Highest output power was obtained by the MZI symmetrical design at 0.90 a.u, which suggests better waveguide design for sensing applications.
  • Publication
    A brief overview of detectors used for terahertz imaging systems
    ( 2020-01-08)
    Shahrir Rizal Kasjoo
    ;
    Mohd Mokhar, Mohd Bazli
    ;
    Nor Farhani Zakaria
    ;
    Nurjuliana Juhari
    This paper presents a short review on terahertz imaging systems based on several types of technology used in the terahertz detection schemes. Some commercial products from ThruVision Systems Limited Company have utilized GaAs Schottky diode detector at 0.25 THz to produce passive terahertz images for public and homeland security. On the other hand, TeraSense Group Incorporated Company has developed and invented a ground-breaking technology which employs sensor consisting of a matrix of plasmonic semiconductor detectors in their latest products to generate terahertz images in the 0.1 - 1.0 THz frequency range. Recently, the utilization of two-terminal unipolar nanodiodes, known as the self-switching diodes (SSDs), as terahertz detectors has shown promising results. The planar structure of SSD not only enables the device to operate at high frequencies due to low intrinsic parasitic capacitance, but also allows the realization of the device using only a single lithography step. This makes the fabrication process of SSDs faster, more simple, and at lower cost when compared to other electronic devices such as Schottky diodes. The development and recent achievement of SSDs as terahertz detectors are also presented in this paper.
  • 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
    Analysis of an electrically induced optical waveguide in a c-axis barium titanate thin film
    ( 2021-12)
    Arif Mawardi Ismail
    ;
    Prabakaran A/L Poopalan
    ;
    Nurjuliana Juhari
    ;
    Mohd. Azarulsani Md. Azidin
    In this paper, we report our analysis of an electrically generated optical waveguide in a 𝑐- axis barium titanate (BTO) thin film. The waveguide consists of a BTO thin film which is sandwiched between two electrodes. The thin film forms a waveguide when a voltage difference is applied across the electrodes. It is found that the formed waveguide supports both TE and TM modes, with TM modes more tightly confined within the waveguide than TE modes. The possibility to turn the waveguide on and off simply by turning the electric field on and off may prove useful for optical switching.
  • Publication
    An overview of semiconductor rectifier operating in the millimeter wave and terahertz region
    ( 2020-01-08)
    Mohd Mokhar, Mohd Bazli
    ;
    Shahrir Rizal Kasjoo
    ;
    Nurjuliana Juhari
    ;
    Nor Farhani Zakaria
    An imaging system operated at millimeter (MM) waves and terahertz (THz) frequencies can be used in many applications such as safety monitoring, public security, medical, healthcare and manufacturing. Typically, these systems utilize rectifying antenna (rectenna) to convert electromagnetic radiation into usable DC power which will be used to generate images. One of the main components of rectenna is the rectifier. Hence, this paper explores the current review on several semiconductor rectifiers that have been significantly deployed for MM-wave/THz imaging systems. This includes Schottky diodes, metal-insulator-metal (MIM) diodes, self-switching diodes (SSDs) and ballistic rectifiers (BRs). The rectifying performance of these devices are discussed in terms of their voltage responsivity and noise-equivalent power (NEP). The standard fabrication process of each device is also presented in this paper as well as their recent development and achievement as high-frequency rectifiers for MM-wave/THz imaging systems.
  • 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
    Low-cost tilt monitoring system for spin coater calibration
    ( 2024-02-08)
    King C.Y.
    ;
    Mohd Fairus Ahmad
    ;
    Norhayati Sabani
    ;
    Mohd Natashah Norizan
    ;
    Nor Farhani Zakaria
    ;
    Nurjuliana Juhari
    ;
    Shamsul Amir Abdul Rais
    ;
    Amin M.R.R.M.
    The spin coating process became the most widely used technique in the fabrication industry for thin film coating on a substrate by centrifugal force. Unfortunately, frequent usage of spin coater might induce a tilted surface of the chuck (i.e. the sample holder). A tilted chuck might induce inhomogeneity of the coating layer. Among the machine's calibration techniques, nullifying the tilt before the spin coating process is the most important step. However, to our knowledge, none of the spin coaters was introduced with the chuck's tilt monitoring during the spin coating process. Thus, investigating the discrete condition during the spin coating process is necessary. In this work, the tilt monitoring system for the spin coater was implemented based on an Arduino Uno microcontroller and distance sensor. A spin coater has been implemented to test the tilt surface monitoring during spinning ranges from 350rpm to 1000rpm. The measurement was done under two conditions: flat (0.00 degrees) and tilted (5.71 degrees). The setup was able to measure up to 0.01 degrees of the tilt.
  • Publication
    Design of arrayed waveguide grating (AWG) demultiplexer based PMMA for narrow channel spacing
    ( 2020-01-08)
    Nurjuliana Juhari
    ;
    Yusof, Muhammad Fadzliazuan
    ;
    Mohamad Halim Abd. Wahid
    ;
    Nur Syakimah Ismail
    Arrayed Waveguide Grating (AWG) based PMMA polymer that functioning as multiplexer/demultiplexer (mux/de-mux) having good potential in WDM system and interferometer optical sensor. Besides, AWG is suitable for larger count optical signals and good filter response devices. AWG demultiplexer based polymer was simulated using Beam Propagation Method (BPM) under TE mode with 1550 nm central wavelength. This work explores the performance of polymer-based AWG with straight waveguide structure that capable to produce 16-channels AWG device for 100 GHz (0.8 nm) channel spacing. The 16-channels AWG based polymer produces low insertion loss of 3.430 dB and low crosstalk of -24.763 dB. The central wavelength for each output port gives almost similar values with the standard ITU-T DWDM wavelength grid with the smallest difference of 0.5 nm. This proposed device also capable to solve the demand on higher channel capacity especially to support internet usage and the needs of the best communication system.
  • Publication
    Effect of heating power towards synthesis of carbon dots through microwave pyrolysis method for optical-based biosensor
    ( 2020-01-08)
    Nur Syakimah Ismail
    ;
    Husain, Umi Shahirah
    ;
    Selvan S.
    ;
    Mordani, Nor Afnia
    ;
    Nurjuliana Juhari
    ;
    Nur Hamidah Abdul Halim
    This study focuses on the effect of heating power in producing carbon dots (CDs) using microwave-assisted pyrolysis from glucose and PEG-200. Glucose is one type of saccharide that contains carbon atom in their structure while PEG-200 is a polymer that acts as a stabilizer. Synthesis of CDs was carried out by using a domestic microwave at different heating power ranging from 300 to 600 Watts. Produced CDs were subjected to dilution, filtering and dialysis procedure for purification purpose. UV-Vis was carried out using PerkinElmer Lambda 35 Spectrophotometer to prove the present of carbon dots in the sample solution. Photoluminescence intensity was observed using Horiba FluoroLog Spectrophotometer together with Horiba iHR550 Imaging Spectrometer to show the emission wavelength and the emission color of CDs prepared. UV-Vis results show the present of CDs in each sample from absorption peaks in the range between 240 nm until 260 nm. The photoluminescence testing shows the emission wavelength of prepared CDs solution is around 430 nm to 570 nm which represent emission color of green-yellow luminescence. From this experiment, CDs that were prepared using a heating power of 450 Watt in 2 minutes and went through the filtering process produce the best luminescence properties. Prepared CDs display electrochemiluminescence (ECL) properties in the presence of co-reactant potassium peroxydisulfate using cyclic voltammetry to pave the way for optical-based biosensor application.