Abstract. In this paper, we analyzed J-V curve of the Dye-Sensitized Solar Cell (DSSC) using numerical calculations. The simulation is based on differential equation of photoelectrochemical in the DSSC. Using internal parameters of the DSSC (L, D, n0, t) appropriate for TiO 2 , we calculate the J-V curve numerically. The analysis is performed by also making variations in temperature, irradiant, absorption constant and photoelectrode thickness. We found that irradiant affect the J-V curve significantly compared to the three other variables. The change in absorption constant needs to be in a factor at least in order of 100 or more to obtain a change, which is considerably high in J-V curve. It is also found that the thickness of photoelectrode should be carefully considered since very thin thickness cannot support DSSC process.
Single-phase calcium titanate (CaTiO3) was successfully synthesized by mechanical milling and the solid-state reaction of CaCO3 and TiO2. The speed of high energy ball milling was 700 rpm with the ball and jar were made from stainless steel. The milling time and ball to powder ratio was 10 h and 50 h, respectively. After milling for 10 h, the mixed powder of CaCO3 and TiO2 experienced heavy milling, which indicated by the average particle size before and after milling was > 1 µm and 85.56 ± 35.62 nm, respectively. Furthermore, the XRD pattern of milled powder revealed the disappearance of CaCO3 peaks and a considerable reduction of TiO2 peaks after milling for 10 h. Moreover, the presence of CaTiO3 peaks in the milled powder was noticeably detected in the XRD pattern, showing the mechanical alloying of CaCO3 and TiO2 was occurred. The milled powder was calcined at 800, 900 and 1000°C for 2 h. The results showed the formation of a single phase of CaTiO3 after calcination at any temperatures. However, the samples indicated the presence of Fe2O3, which from the milling media. The presence of impurities after milling is inevitable due to friction between ball and jar. Further study is needed to obtain the optimum condition of mechanical milling to minimize the contamination.
Nano-sized manganese oxide was synthesized by the solvothermal method. Manganese sulfate was used as a precursor, which is obtained from the Sumbawa manganese ore. Two kinds of the precipitating agent, ammonium persulfate and sodium hydroxide, were used in this study and the effect on the solvothermal product were examined thoroughly. The solvothermal temperature and time were 120°C for 18 hours, respectively, for both precipitating agents. The results showed that the phase of manganese oxide was influenced by the precipitating agent, as indicated by X-ray diffraction analysis. Phase <x-MnO2 was obtained from the reaction between MnSO4 and ammonium persulfate, while Mn3O4 for the sodium hydroxide. The formation of a-MnO2 was influenced by the excess of NH4
+ which came from the manganese ore leaching into MnSO4. One notable finding in this study is that the morphology of manganese oxide was also affected by the precipitating agent. For instance, the shape of MnO2 and Mn3O4 was needle and sphere, respectively. Moreover, the strict long thinner needle of <x-MnO2 was formed and the aspect ratio increased at a higher temperature. While the particle size of Mn3O4 decreased with the increased temperature. These results imply that variation of a precipitating agent is imperative to obtain the specific manganese oxide product, including the shape.
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