STUDY ON CONSISTENCY AND DENSITY OF TITANIUM DIOXIDE AND TUNGSTEN TRIOXIDE COATINGS ON CONDUCTIVE GLASS FROM DIPPING PROCESS AFFECTING LIGHT ABSORPTION AND TRANSMISSION

Light property is a crucial factor in photovoltaic power generation. Therefore, the study of light absorption and transmission of materials is important for developing of solar cell coating material. Titanium dioxide (TiO2) and tungsten trioxide (WO3) are the important candidates for use as the solar cell coating material. Because TiO2 and WO3 have a narrow energy band gap and have photocatalytic properties which are the essential properties for the solar cell application. The aim of this work is to investigate the light absorbance ability of the TiO2 and WO3 coating layer. The gel of TiO2 and WO3 was synthesized by the sol-gel method. The synthesized gel of TiO2 and WO3 was coated on the conductive glass (FTO) by using the dip-coating technique. The light absorbance of the coated surface was examined by the UV-Visible Spectrophotometer technique (UV-Vis). The surface of coating homogeneity and the coating density were evaluated by 3D imaging which was investigated by 3D reconstruction of the samples by Synchrotron X-ray tomographic microscopy (SR-XTM) technique. The results show the light absorption ability of the conductive glass coated by WO3 is higher than that of TiO2. However, the coating homogeneity and the coating density of the WO3 coated layer are lower than that of the TiO2 coated layer. The unevenness of the WO3 coated layer is the cause of non-uniform light absorption. The homogeneity of the coating layer is decreased with increasing the coating layer number because the coating is unevenly distributed resulting in some areas are denser than others. From all the experimental results, it is concluded that even the TiO2 coated layer has a tendency to increase the absorbance less than WO3 coated layer, but it is acceptable considering of uniformity coated layer. Consequently, TiO2 is suitable for applying to solar cells because of its increasing of absorbance capacity and reducing of light reflection.