Hasil Pencarian  ::  Simpan CSV :: Kembali

Abstrak :
Santa Barbara Amorphous-15 (SBA-15) is an interesting mesoporous silica material with highly ordered nanopores and a large surface area. Due to its unique properties, this material has been widely employed in many areas. This study aimed to predict the number of nanopores per gram of SBA-15 material based on an optimum value of surfactant addition at the desired number of nanopores. For this purpose, SBA-15 was synthesized via a sol-gel process using tetraethyl orthosilicate (TEOS, Si(OC2H5)4) as a precursor and pluronic P123 triblock copolymer surfactant (EO20PO70EO20, EO = ethylene oxide, PO = propylene oxide) as a template. There were five different surfactant concentrations, namely 0.35, 2.50, 2.70, 3.00, and 3.30 millimoles, used with a fixed concentration of TEOS. The characterization was performed using small-angle x-ray scattering (SAXS), adsorption-desorption (BET), and transmission electron microscopy (TEM). The results showed that the surfactant concentration did not affect the crystal structure, although an increase in the surfactant concentration linearly correlated with an increase in the surface area. The shape and size of the pore diameter tends to be approximately 3 nm, as characterized using BET adsorption-desorption. The optimum concentration of surfactant for the formation of mesoporous SBA-15 material was 2.70 millimoles. The value obtained in this study was in accordance with the calculated value, indicating that the theoretical calculations can be used to experimentally predict the number of pores.

Abstrak :
Fluorine-doped tin oxide (FTO) is one of the conductive glasses that have strategic functions in various important applications, including dye-sensitized solar cell (DSSC). In the current work, the effects of deposition time (5, 10, 20, 30, and 40 minutes) upon the fabrication process of FTO thin film using spray pyrolysis technique with modified ultrasonic nebulizer has been studied in regard to its microstructural, optical, crystallinity, and resistivity characteristics. The variation was also performed by comparing the pure tin chloride precursor and the solution that was doped with fluor (F) at 2 wt% in order to see the doping effect on the properties of thin film. The thin films were characterized using x-ray diffraction (XRD), scanning electron microscope (SEM), ultraviolet-visible (UV-Vis) spectroscopy, and digital multimeter. On the basis of current investigation, it has been found that the best FTO was obtained through the pyrolysis technique of 20-minute deposition time, providing optical transmittance of 74%, a band gap energy (Eg) of 3.85 eV and sheet resistance (Rs) of 7.99 Ω/sq. The fabricated FTO in the present work is promising for further development as conducting glass for dye-sensitized solar cell (DSSC).

Abstrak :
Transparent conducting oxide (TCO) glasses play an important role in various technology, including dye sensitized solar cells. One of the most commonly used glass is indium tin oxide (ITO) glass, which is expensive. Therefore, the main purpose of this research was to determine if ITO glass can be replaced with fluorine-doped tin oxide (FTO) glass, which is easier and more economic to manufacture. For this purpose, a tin chloride dehydrate (SnCl2.2H2O) precursor was doped with ammonium fluoride (NH4F) using a sol-gel method and spray pyrolysis technique to investigate the fabrication process for conductive glass. NH4F was doped at a ratio of 2 wt% in the SnCl2.2H2O precursor at varying deposition times (10, 20, and 30 minutes) and substrate temperatures (250, 300, and 350°C). The results revealed that longer deposition times created thicker glass layers with reduced electrical resistivity. The highest optical transmittance was 75.5% and the lowest resistivity was 3.32´10-5 Ω.cm, obtained from FTO glass subjected to a 20-minute deposition time at deposition temperature of 300oC.