Investigation of novel low temperature atmospheric pressure plasma system for deposition photo-catalytic TiO2 thin film

The purpose of this study was to develop a novel low-temperature atmospheric pressure (AP) plasma system and to use the system to deposit photo-catalytic titanium dioxide (TiO2) thin film. In this study, titanium tetraisopropoxide (TTIP) was used as a precursor for TiO2 thin film deposition. The precursor was vaporized by ultrasonic oscillator and introduced into an atmospheric plasma system by argon (Ar) carrier gas. The main plasma working gas was Ar mixed with O2. Microstructure evolutions of TiO2 thin film were investigated by low-angle grazing-incidence x-ray diffraction (GID), x-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), and transmission electron microscope (TEM). The photo-catalytic properties were determined by contact angle and methylene orange de-coloration testing. In this study, the substrate temperature, the precursor flow rate and the O2 flow rate were varied. TiO2 thin film grown at a temperature of 350 °C, with precursor and O2 flow rates of 20 sccm and 200 sccm, respectively, revealed the optimum photo-catalytic properties. It was also found that titanium dioxide thin films synthesized by the AP plasma method possess reasonable photo-catalytic characteristics like other deposition techniques.

Research highlights
► We developed a novel atmospheric plasma system to deposit photo-catalytic TiO2.
► Titanium tetraisopropoxide (TTIP) was used as a precursor for TiO2 deposition.
► The main plasma working gas was argon (Ar) mixed with O2.
► The optimum photo-catalytic TiO2 grown at a substrate temperature of 350 °C.
► TiO2 films synthesized by atmospheric plasma possess good photo-catalytic properties.