Cyclic voltammetry can be used to investigate the chemical reactivity of species ion via oxidation and reduction process. The purpose of this study is to determine the level energy of high occupied ...molecule orbital (HOMO) and low unoccupied molecule orbital (LUMO) in polythiophene (PT), Poly (3-thiophene acetic acid) (P3TAA), polypyrrole (PPY) and chlorophyll (Chlo) through oxidation and reduction of molecular ions by cyclic voltammetry method. PT, P3TAA, PPY and Chlo solutions were prepared in a solvent of acetonitrile at the concentration range of 10-2 to 10-4 M. The current-voltage measurements for these solutions are performed using cyclic voltammetry method on input voltage from -2.0 V to 2.0 V. The working electrode used is indium tin oxide (ITO). The result of voltammogram is showed that the activity of PT species were produced three oxidation and one reduction processes. The formal reduction potential, Eo¢ is 0.83 (positive) meaning that oxidation process was dominant. So that the reaction of PT species was exhibited irreversible electrochemical behavior. The reaction of P3TAA species was exhibited reversible electrochemical behavior, where the range value of oxidation, DEpa and reduction, DEpc were in range of 0.825 V to 1.120 V and -0.230 V to 0.131 V respectively. PYY species reaction was exhibited irreversible electrochemical behavior where two oxidation states occur within -0.145 V to -0.202 V and 0.870 V to 1.63 V respectively. The species activity of Chlo was exhibited irreversible electrochemical behavior where only the oxidation process was obviously appeared at range of 0.80 V to 0.95 V. The LUMO energy levels of PT, P3TAA PPY and Chlo were 5.84 eV, 5.34 eV, 1.10 eV and 3.85 eV respectively, while HOMO energy levels of PT, P3TAA PPY and Chlo were 4.61 eV, 4.25eV, 3.70 eV and 5.93 eV. The average value of energy gap of PT, P3TAA, PPY and Chlo were 1.23 eV, 1.08 eV, 2.23 eV and 1.10 eV respectively.
Solid state dye-sensitized solar cell (ss-DSSC) was developed to overcome the problem arise from electrolyte leakage in liquid state dye-sensitized solar cell. This work focused on the fabrication of ...ss-DSSC based on inorganic semiconductor of titania and organic conducting polymer of poly (3-hexylthiophene) (P3HT) and natural dyes from purple seaweed (PS dyes) via electrochemical, spin coating and dip coating method, respectively. The absorption spectrum and functional group of PS dyes were investigated using UV-Visible absorption spectroscopy and Fourier Transform Infrared (FTIR) spectroscopy; respectively. Meanwhile, the effect of immersion time of PS dyes on performance of the device was studied via current density-voltage (J-V) characteristic. PS dye was absorbed in a wide range of solar spectrum in visible and near-IR region by chlorophyll a, phycocyanin and zeaxanthin pigments exists in the PS dyes. The present of carboxylic groups in PS dyes which bound to P3HT and formed P3HT-COOH enable the linkage to TiO2 surface which helps in the transfer of electrons from natural dyes to the conduction band of TiO2 film. The highest efficiency obtained was 1.44% at 10 minutes time of immersion. This concludes that PS dyes was a good photosensitizer and can be applied in ss-DSSC.
High performances of Hybrid Dye Sensitized Solar Cell are necessary in absorbing more sunlight and needed renewable energy source to replace depleted fossil fuels via green energy. Hybrid DSSC is ...another promising option towards green energy to explore. This research aims, i) to study conjugated chlorophyll in order to increase charge carrier in molecule structure besides, increase the absorption spectrum via conjugating process with the addition of different amount Ferric (III) Chloride (FeCl3) acting as catalyst and, ii) to determine the effect of FeCl3 on the performance of conjugated dye as sensitizers in Hybrid DSSC. The conjugated chlorophyll shows a using UV-Visible analysis corresponding to conjugated chlorophyll absorbed in high region called red shifted which the maximum absorption obtain at a wavelength of 360nm and 311nm. Fourier Transform Infra-Red characterization of the an existing Fe-O bond appears at 430 cm-1 to 445 cm-1 and C≡C bond at 2244 cm-1 to 2260 cm-1. 10% FeCl3 in conjugated chlorophyll produce huge impact to electrical conductivity and efficiency with the highest value; 0.114 S/cm and 0.14%; respectively. Thus, it can be conclude that 10% FeCl3 of conjugated chlorophyll – Imperata cylindrica (iCHLO-IC) was suitable to be used for the next generation of hybrid DSSC.
This work focused on the electrical and Hall Effect of Organic Solar cell (OSC). In this work, Indium Tin oxide (ITO) glass as substrate was heated at 50 °C to 200 °C. The polymer used was Poly ...(3-Dodecylthiophene) (P3DT) thin film and Downy Rose Myrtle berries (Rhodomyrtus Tomentosa (Ait.) Hassk.) as dye. The P3DT were deposited on the ITO substrate using electrochemistry method at room temperature. While, the dye of Downy Rose Myrtle berries was deposited by layered using spin coating method. The electrical conductivity of ITO deposited thin film was explored by four point probes (FPP) under dark and under light radiation (range of 10 Wm-2 to 200Wm-2). From FPP study, the electrical conductivity was increased by the increment of light intensity and temperature of substrate. Lastly, the samples were examined using Hall Effect measurement to obtain the type of sample, Hall mobility, and highest charge carrier in the sample of OSC. The results show that the sample is suitable for further solar cell application.
Purpose
Despite the extant literature on purchasing behaviour, little is known about why and how consumers purchase and use pharmaceutical products in Malaysia. This paper aims to develop a holistic ...model that articulates the factors underlying pharmaceutical product purchase and use and their relationships.
Design/methodology/approach
Drawing upon the grounded theory approach, in-depth interviews and analysis on the basis of theoretical saturation were conducted. Enumerators, trained to perform interviews, the transcription and content analysis, sampled 120 Malaysian consumers in the first phase and 40 in the second. ATLAS.ti was used to assist the coding and analytical process.
Findings
The findings largely support extant literature on purchasing decisions. Particularly, the evaluation of product attributes was found to be an immediate determinant of purchase and use. The effect, in turn, was moderated by personal factors and facilitating conditions. The need for healthcare products and the knowledge about them were constructed as antecedents in the model. The study also highlights that consumers’ purchase and use of pharmaceutical products could be better understood and managed with a holistic view of the decision-making process.
Originality/value
This study proposes the conbe-hepro model to explicate the antecedents and determinants of consumers’ purchase and use of pharmaceutical products in the Malaysian context. It provides a theoretical grounding that enriches our knowledge of the changing behaviour of consumers in healthcare literature. It also yields practical insights to the government bodies and the healthcare providers in Malaysia and other developing countries.
Hippocampal volume is affected by several psychiatric illnesses of old age, as well as by normal aging. It is important to have a normal data in a population to assist in diagnosis. The aim of this ...study is to determine hippocampal volume in normal Malay people aged 50 years old and older.
This was a cross-sectional study of the normal Malay population aged 50 to 77 years. We included 43 participants, representing 19 men and 24 women. Magnetic resonance imaging (MRI) was performed using a GE Signa Horizon LX 1.0 Tesla. Oblique coronal images of temporal lobes were obtained and hippocampal volumetry was done manually and normalised with intracranial volume.
Mean right and left hippocampal volumes (HCVs) were 3.43 cm³ (SD 0.32) and 3.26 cm³ (SD 0.34), with a significant difference between them (P < 0.001). Total mean HCVs exhibited no significant difference between men and women (P = 0.234). The means of the normalised right and left HCVs were 3.42 cm³ (SD 0.31) and 3.26 cm³ (SD 0.32).
The mean right and left hippocampal volumes were significantly different in this study. Men had slightly larger mean HCVs but the difference was not statistically significant. It was found that normalisation further reduces the mean volume difference between the genders.
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