71
CHAPTER 5
DISCUSSION
5 Discussion on relations of different surface morphology to crystallite size
5.1 Surface morphologies of TiO
2
thin films on different substrates
SEM micrographs of the surface morphology of the AgTiO
2
thin films onto different substrates calcined at different temperature indicated that the coating was smooth and
uniformed and it seemed to agglomerate at certain areas. It was shown that the glass coated surface was not smooth and uniformed, leads to the assumption that the layers were not
sufficient enough to accommodate to the uniformed layer on the surface. There is also another possibility that the lack of layers that have been coated onto the substrates may have
shown the inconsistent coating layers. For the dip-coated glass substrates, large agglomerate size can also be observed due to the coagulation formed in the dip-coating process, which can
affect the effective surface area of the coating and may further reduce the photocatalytic activity. The surface may also have been affected by the way the dipping method and the
drying of each substrate were applied. The dipping method has to be ensured that the substrate is placed vertically at 90° degree and dipped in different sol gel solution that should
not be shared with other substrates. While the drying method which is to ensure the water was dehydrated and the way the substrate was to be put in such a way that the sol gel would
not puddle on the surface.
72 As stated before, the films were porous and the particles were seen approximately
spherical. It was assumed that the particles aggregated during the deposition and calcinations processes. The average particle sizes of glass and AP were estimated to be about 37 and 57
nm in diameter, respectively correspond to the calculated particles from Scherrer equation. EDS test was carried out simultaneously with SEM analysis. The high weight
composition analyses corresponded with the concentrations of all the elements in the coating i.e Ti and O. As Ag was found remarkably low at each substrate, it is due to the fact that Ag
was doped only one layer, thus giving the value of low intensity height. There was also the existence of carbon content, C, as it came from the hydrolysis of ethanol C
2
H
5
OH and TTiP Ti[OCHCH
3 2
]
4
with the formulation.
5.2 XRD Characterization of the AgTiO
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