Physical Structure Analysis and Optical Properties of Sudan III Thin Film

Background: Sudan III is known red disazo dye possess a hydroxyl group which is sensitively to interact with others molecules such as CO2, O2, SO2 through hydrogen bonding. Methods: Fabrication of Sudan III thin film for sensor technology application has been carried out by using PVD method. The physical structure that is crystallinity of this film has been investigated by using XRD method. Results: The XRD spectra of powder Sudan III shows crystalline structure while the XRD spectra of thin film results of the PVD method, which is deposited on substrate glass slide shows amorphous structure. There are no differences in the crystallinity content of Sudan III thin film that exposure to acetone and alcohol vapor. The interplanar distance of crystals plane is about 28.47 nm, the average crystallite size is about 35.6 nm and the average molecular chain separation is about 37.9 nm. Sudan III thin film result of the PVD method shows an interesting optical characteristic (absorption). There are significantly different between UV-VIS spectra Sudan III thin film compared to the UV-VIS spectra of Sudan III solution. The UV-VIS spectra of the Sudan III thin film shows a decreasing of peak intensity in visible wavelength which indication of orientation effect of molecule on substrate surface. The aborption peak at UV region for Sudan III thin film shows a shifting to the long wavelength compared to the Sudan III in form of solution.