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We propose a solar cell design using the combination of titanium dioxide (TiO 2 ) and graphite as active photon absorbing materials. TiO 2 absorbs photons of nearly ultraviolet wavelengths to produce electron-hole pairs, while graphite is expected to absorb photons of longer wavelengths. Although many authors have claimed that graphite is a semimetal, we observed that a model of a solar cell containing TiO 2 only as the active material behaves exactly the same as a model containing graphite only as the active material. Additionally, we observed that a model of a solar cell made using a composite of TiO 2 and graphite as the active material had much higher efficiency than solar cells made using TiO 2 -or graphite-only active materials. Although the highest efficiency we report here is approximately 1 %, our proposed solar cell structure is promising for mass application, especially in low-income settings, owing to its easy and flexible fabrication, and easy largescale application.

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We described a novel system for applying titanium dioxide (TiO2) particles on the surface of transparent plastic fibers and the use of the coated fibers as photocatalysts to decompose organic pollutants in water. We examined several coating parameters to identify the optimum conditions and used the coated fibers to decompose organic pollutants in simulated waste solutions. The coated fibers were scattered on the water surface and the catalytic reaction proceeded during several days of exposure to sunlight. After completion the decomposition process, the coated fibers were easily recovered using a filter. A simple model is also presented to explain the experimental findings. This method is useful for purifying contaminated water under solar illumination and requires very little energy input. © 2011 American Institute of Chemical Engineers Environ Prog, 32: 42–51, 2013.

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The present work focused on the effects of TiO2 in degrading organic wastewater. Technical TiO2 of anatase crystalline phase was used. TiO2 photocatalyst showed a powerful result in destroying organic effluent. Spray coating was conducted to immobilize the TiO2 particles onto the plastic buffer followed with heat-treatment process. As a result, 30 mL of 25 mg L−1 methylene blue (MB) used in the photocatalyst test was sucessfully degraded after 4 hours of irradiation. Repetitive use of the TiO2 films still has a great photodecomposition ability of removing 99% of the organic contaminant after 5 times use.

Deposition of smaller granular particles on a larger nucleus particle has been simulated in two-dimension using molecular dynamics method. Variation of sequences of velocity of deposited particles is conducted and reported in this work. The sequences obey a normal distribution function of velocity with the same parameters. It has been observed that for velocity in range of 0 to 0.02 the densest deposited site (15-17 % number of grains) is located at about angle π/4 where location of injection point is π/4. And the less dense is about π/4 + π/2. Different sequences give similar result.