Advanced Materials Research Vol. 545

Abstract: Lamellar hydrotalcite (HT) was synthesized in the laboratory following combustion method. Tapai fueled HT was found to exhibit more orderly packed microstructure and was more crystalline in nature than its urea fueled counterpart, particularly at higher combustion temperature. The pore structure of tapai fueled HT resembled that of bottle neck with possibility of tapered with open-end that might also be present. The crystal size of tapai fueled HT was larger than urea fueled HT but greater size reduction was experienced by the former material, suggesting that more energy might have been supplied to the sample to disintegrate the particles, since tapai has higher and cleaner carbohydrate source than urea.

Abstract: Dye sensitized solar cell (DSSC) is a new class of low-cost solar cell, that belongs to third generation solar cells in thin film based. It is based on a semiconductor formed between a photo-sensitized anode and an electrolyte, known as photoelectrochemical system. A lot of research has been conducted due to their interesting potential for low-cost, lightweight, disposable and having cell efficiency up to 10%. This paper reports the fabrication of dye sensitized solar cells using TiO₂ nanoparticles and chlorophyll as active layer. TiO₂ nanoparticles were prepared by sol-gel method while the chlorophyll was extracted from Pandanus amaryllifolius (Pandan leaf). TiO₂ film was prepared on ITO coated glass using dip coating technique and then immersed overnight in the chlorophyll solution. An electrolyte solution composed of PC-LiClO₄ was injected into the cell before sealed using glass that was coated with Pt as top electrode. An active area of 4.48 cm² was fabricated by black masking the front side. The performance of the device was studied by observing the current-voltage characteristics of the device in dark at ambient temperature and under illumination of 100 mW/cm² light. It was found that the device showed rectifier property in the dark and able to generate electrical current under light.

Abstract: Fe₂O₃ was synthesized via a sol-gel method. Pure, single phase materials were obtained at 300 °C and 800 °C heated for 24 hours. The conductivies of the materials were investigated using a.c. impedance spectroscopy. It was found that the material annealed at a lower temperature gives better conductivity value of about two orders of magnitude higher.