Applied Mechanics and Materials Vols. 773-774

Abstract: Solar power system is one of the renewable sources that will be used to produce electricity because of its characteristics such as consumed free source of sun light, less maintenance needed for the system and free of charge for usage electricity. One of the main disadvantages is the initial cost of the equipment used to harness the suns energy especially the cost of solar panel. In Malaysia, the cost of solar panel are relatively high because the solar panel are imported from overseas and the materials used in existing solar panel is very expensive. Therefore the proposed solar cells that will be used is natural dye sensitized with photovoltaic material. The scope of this research is to full fill the demand of low cost and to abundance, renewable material that could be used for energy conversion solar cell. The circuit connections of solar cells are in series and the performance of the dye sensitized cells would be based on the intensity of the sunlight illumination. The measurement of solar cell are conducted using 10 dye sensitizied cells connected in series circuit arrangement and the performance for this design are evaluated based on the generated potential (V) upon sunlight illumination at noon and evening for certain period of time. The result obtained from this research shows that the performance of series circuit connection of the dye sensitized solar cell is comparable with the silicon solar cell.

Abstract: Fabrication and performance of metal-semiconductor-metal (MSM)–type intrinsic zinc oxide-coated, aluminium-doped ZnO nanorod array-based ultraviolet photoconductive sensors were reported and discussed. The Al-doped ZnO nanorod arrays were prepared using sonicated sol-gel immersion method. The coating process of intrinsic ZnO onto Al-doped ZnO nanorod arrays was performed using radio-frequency (RF) magnetron sputtering at different deposition times varying from 0 to 10 min. We observed that responsivity of the sensors decreased with increasing intrinsic ZnO deposition time, decreasing from 4.81 A/W without coating to 1.37 A/W after 10 min of coating. Interestingly, the sensitivity of the sensors improved with intrinsic ZnO coating, having a maximum value of 19.0 after 1 min coating.

Abstract: Engineering and decoration on the surface of metal oxide semiconductor (TiO₂) for increasing activity is challenging. Thus a novel method is introduced to determine surface morphology quality subsequently improving the photocatalytic behaviour. TiO₂ films are fabricated via laser deposition technique at various CdS thickness. Microstructural characterization and optical behaviours are characterized by felid emission scanning electron microscope (FE-SEM) and atomic force microscope (AFM). The hydrophilic property of TiO₂/CdS nanocomposite film (NCF) is examined via contact angle measurements. The grain density is found linearly increased with the contact angle. A mutual relationship is revealed between hydrophilic property and crystallization with respect to the CdS thickness. Thus, surface morphology of nanocomposite quality is quantified based on the hydrophilic measurement

Abstract: We have reviewed humidity sensors based on the Zinc oxide (ZnO) humidity sensor. There are only a few papers reviewing on the ZnO humidity sensor. The characteristics, structures, advantages, and fabrication methods of ZnO have been studied to understand the suitability of the ZnO to be applied at different kind of condition such as for extreme environment, low level humidity detection, and very high humidity level circumstances. The electrical and physical properties of ZnO humidity sensors such as sensitivity, response time, stability, uniformity, and crystallinity have also been discussed in this review. ZnO nanostructures have been widely used for humidity sensors because of its’ good stability, high sensitivity for humidity-sensing, low cost, and has a wide band gap. Sol-gel preparation method is commonly used to for ZnO humidity sensor fabrication since it can produce a film with high uniformity, simple process and low cost. Keywords: Humidity Sensor, Metal Oxide, Semiconducting Type, Ceramic Type, Humidity-Sensing, Band Gap, Sol-Gel Preparation Method.

Abstract: Recently, copper oxide thin film has been studied because of its low cost, sensitivity to ambient condition and easiness to produce oxide thin film. It is one of the p-type semiconductor oxides materials that are suitable to be used as gas sensing material. In order to improve the sensitivity and to optimize the properties of copper oxide thin film, it is essential to study the physical structure of copper oxide. In current studies, copper oxide thin film has been deposited by RF magnetron sputtering at different substrate bias voltages and oxygen flow rates. The results reveal that the deposition rate decreased when the oxygen flow rate above 4 sccm. SEM image reveal that nanostructure copper oxide was also obtained when the oxygen flow rate was above 4 sccm. On the other hand, no significant effect on the substrate bias voltage toward the sputter deposition rate was observed.

Abstract: Atomic force microscope (AFM) is a useful tool to capture the two- and three-dimensional image of height and size of nanostructured thin film. It operate by measuring the forces between a sharp tip and surface of the measured sample. In addition, AFM is equipped with powerful software for image processing to interpret experimental results in detail. For example, by using the height and scanning length parameters of measured sample, average roughness and root mean square roughness can be evaluated. In the present works, the effect of image flattening process toward the surface roughness and surface fluctuations of metal oxide thin films will be presented. Set of samples were prepared by magnetron sputtering deposition and sol-gel coating techniques. In gas sensor industries using metal oxide thin film, surface roughness of metal oxide thin films are very important in order to improve the sensitivity and respond time of gas sensor. Therefore, optimization of thin film deposition and characterization are very important. The correlation between the three-dimensional image and thin film deposition and image processing parameters will also be presented.

Abstract: Glucose biosensor has been improvised from time to time in order to provide fast and accurate detection of glucose concentration especially for diabetic patients. Recently, nanoparticles have rising attention engaging with biosensor application. Nanoparticles serve as the carrier of enzyme immobilization whereas; enzyme is a biological catalyst that reacts with specific substrate in metabolic reaction. Glucose oxidase (GOx) in particular, is the most common enzyme used for fabrication of biosensor. Glucose measurement was done by using amperometric measurement that converted corresponding biochemical reaction between glucose and GOx into electrical output. Response behavior studies were conducted in order to compare the successfulness of GOx immobilization onto GOx-biosensor. Immobilization of glucose oxidase onto nanoparticles can lead towards tremendous impacts especially in new, high sensitivity biosensor.

Abstract: Aligned Rutile TiO₂ nanorods (r-TNRs) and TiO₂ nanoflowers (r-TNFs) were successfully prepared by hydrothermal method. Using hydrochloric acid (HCl) as chelating agent and titanium butoxide (TBOT) as precursor, aligned r-TNRs with r-TNFs were successfully growth onto fluorine-doped tin oxide (FTO) with different morphologies. The influences of surface morphologies to the rutile based Dye-sensitized solar cell (DSC) efficiency are discussed. The highest light-to-electric energy conversion efficiency, 1.80% is achieved using different concentration under simulated solar light illumination of 100 mWcm^-2 (1.5 AM).

Abstract: Dye-Sensitized Solar Cell (DSSC) has been prepared using Cobalt doped Titanium Dioxide (TiO2). The preparation of Cobalt doped TiO2 were done using spray pyrolysis method. Cobalt doped TiO2 thin film were annealed at 500 °C for 3hours and the effects of Cobalt as a dopant, towards the surface morphology and structural properties have been studied. Finally, I-V measurement of DSSC was done under illumination of AM 1.5 and 100mW/cm².

Abstract: ZnO nanorods (NRs) arrays were synthesized by chemical solution deposition (CSD) method on commercial glass substrate with ZnO thin film act as seed layer prepared by sol-gel spin coating. The effect of annealing temperature of 150°C, 250°C and 500°C, respectively, on the structural growth was investigated. The observation reveals the structural improvement as the annealing temperature increased. The influence of gadolinium doping to ZnO NRs arrays was explored upon the structural and optical features. The FESEM imaging along with XRD, AFM and UV-Vis analysis were conducted to dissect the information gained by performing a study case on various gadolinium doping content in the range of 1 at. % to 4 at. %. Based on the results, the correlation between the doping content were drawn in details in this paper.