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.
Hybrid solar cell (HSC) in a form of novel photovoltaic is considered among promising research topic due to its low cost's preparation and environmental friendly solar cells. This paper concerns a ...systematic study on concentration of TiO2 and effect of coating techniques towards solar cells's efficiency. However, this paper is limited to doctor blade and spin coating techniques only. These samples were then characterised based on morphology, thickness, optical absorption, electrical conductivity and solar cell's efficiency using various techniques including FESEM, profilometer, UV-Vis and, autolab with irradiance of 100 mW/m2. From the results, TiO2/PEDOT:PSS with dye Eugenia clavifora (EC) obtained the highest efficiency of 1.33% using doctor blade technique compared to 0.00108% for spin coating technique. Sample thickness was obtained at 60.25 ± 1.20 nm corresponding to the concentration of TiO2 at 0.20 M. Thus, it can be conclude that, power conversion efficiency (PCE) was dependent to the deposition techniques of the thin film.
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.
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.
Organic compound containing thiosemicarbazide moiety has been successfully synthesized. The new synthesized dyes, N-(3-(Trifluoromethylbenzaldehyde)benzylidine thiosemi- carbazide (3-TFT) was ...characterized by spectroscopic technique namely, CHNS elemental analysis, Fourier Transform Infra-Red analysis (FT-IR), UV-Visible analysis (UV-Vis), 1H and 13C Nuclear Magnetic Resonance (NMR). The thin films of this dye have been prepared using a spin coating technique and deposited on indium tin oxide (ITO) glass substrate. The main highlight was an electrical conductivity of thin films which was measured using four point probing system in a range of light intensity, 25 Wm-2 until 200Wm-2. The potential electrical conductivity of 3-TFT dye was found gradually increased until reached the maximum conductivity values of 0.1489 Scm-1 at light intensity of 100 Wm-2 in the most diluted concentration at 1x10-5M.
Pemilihan duta mahasiswa Generasi Berencana (GenRe) bertujuan tegar remaja yang berperilaku sehat, terhindar dari resiko tiga kesehatan reproduksi remaja, menunda usia pernikahan, dan memiliki ...perencanaan kehidupan berkeluarga untuk mewujudkan keluarga kecil bahagia dan sejahtera. Pemilihan Duta MahasiswaGenRe dimulai dari tahun 2010 hingga saat ini, dimana jumlah peserta setiap tahunnya ± 30 pasang dan hanya 1 pasang yang terpilih.Masalah yang muncul masaih ada unsur penilaian secara subyetif dan ada beberapa peserta yang memiliki nilai yang sama sehingga menyulitkan pihak pengambil keputusan untuk menentukan mana yang terbaik, untuk itu diperlukan sebuah sistem pendukung keputusan.Metodeyang digunakan adalah Weighted Product (WP).Berdasarkan hasil penelitian yang dilakukan, sistem ini dapat membantu pihak pengambil keputusan dalam menentukan alternatif terbaik menjadi duta mahasiswa GenRe untuk kategori Laki-Laki dengan nilai tertinggi 0,35119 dan kategori Perempuan dengan nilai tertinggi 0,35013 dan dengan adanya sistem iniproses pemilihannya menjadi lebih obyektif dan mudah.
Abstract
The stable natural resources will encourage the productivity of sustainable eucalyptus replanting for the benefit of human life. Replanting eucalyptus plants is one of the things that drive ...sustainable productivity in eucalyptus processing. Eucalyptus replanting planning requires supporting tool decisions to increase productivity, analyze variability, climate change, measure environmental impacts, and maximize profits. The paper aims to evaluate various models in representing the replanting of sustainable eucalyptus used for crop management. In this review, the discussion started from the history of eucalyptus, the approach to the compilation of literature reviews, the method for reviewing the literature, yields and discussions, and finally providing some significant recommendations. Reviews of physiological models based on 3PG (Physiological Principles in Predicting Growth) processes are considered capable of being optimal support tools in the management of sustainability strategies to evaluate the growth of eucalyptus plant. Its usefulness in providing simulations about the impacts of climate change, simulation of forest management practices, the impact of hydrology on forests, the attributes of location to standing growth, biomass dynamics and potential disruption to forest ecosystems make this model a supporting tool in forest management sustainability strategies. Review literature was obtained relevant literature for qualitative analysis from 2010 to 2021.
Abstract
There are five largest sectors that affected Indonesia’s economic growth in the fourth quarter of 2019, and one of it is plantation. Steps that can be taken to maintain sustainable ...plantation productivity are replanting activities. This study will discuss various models that have been used in previous studies to represent replanting activities as a material for decision making to increase the productivity of weaving in a sustainably manner. This research was conducted by a descriptive analysis of the results of previous research activities that already exist. The results of the analysis of prior studies show that the simulation of the replanting model can provide a representation of the actual shape in the field with various influencing factors. Most of the models convert dynamic factors that affect replanting activities into discrete. This is done to facilitate the analysis of replanting activities. The replanting model simulation has an enormous impact on decision making by the plantation management. The model used in general still needs re-analysis to improve the accuracy of the actual representation in the field.
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