Investigation of antibacterial properties of Mn doped TiO2 thin films

Nowadays, titanium dioxide is a kind of material used for its superior properties such as high whiteness, brightness, non-toxic and strong hiding power.It is also highly preferred because of its excellent chemical stability, biologically non-toxic and low cost.In this study, TiO2 thin films with different concentrations of Mn additive were deposited on the bottomstone using the rotary coating technique.The structural, surface, optical and anti-bacterial properties of the pure and Mn doped thin films deposited on the glass substrate with different concentrations of 10 times and then annealed at 450 ° C using XRD analysis, scanning electron microscopy, UV-VIS spectrophotometry and agar diffusion test, respectively investigated.In this way, it has been possible to control the structural, surface, optical and antibacterial properties by changing the Mn contribution.When the structural properties of the films analyzed by XRD were examined, it was observed that the films with pure annealed at 450 °C and Mn doped were completely formed in anatase structure.The crystallinity of the films varies depending on the increase of the Mn contribution.The XRD peak at 2θ = 25.3 of the annealed samples at 450 ° C showed the crystal plane (101) of tetragonal titanium.This indicates that the films have a single crystal structure and (101) preferential orientation.It was observed that the Mn contribution changed the structural characteristics of the film when the SEM images of undoped and different concentrations of Mn doped TiO2 (0, 1, 3 and 5%) thin films were examined.When SEM images of different concentrations of TiO2 films were examined, cluster structure in the whole surface was observed. However, there are more particles and pores on the 3% Mn doped thin film surface.Optical properties were analyzed by transmission and energy band gap measurements using UV-VIS spectrometry.For the pure TiO2 thin film, the transmission reached the highest of 74.75% at 560 nm. For 1%, 2% and 3% Mn doped TiO2, it shifts to longer wavelengths and causes an increase in the transmission value of TiO2 thin films due to the increase of Mn additive.It is seen that the effect of Mn on TiO2 on the optical energy band gap (Eg), which is drawn on the indirect transition of the films based on the photon energy(hv) versus(αhv)2 graph. The energy band values for TiO2 films with 0%, 1%, 3% and 5% Mn were found to be 3.20, 2.96, 2.75 and 3.10 eV, respectively.For films annealed depending on concentration, the calculated energy band range changes as Mn contribution decreases.When the antibacterial activities of the films were examined, TiO2 films containing 1% Mn showed antibacterial activity against E. coli bacteria and TiO2 films containing 3% and 5% Mn did not show antibacterial activity. Key words: Thin Film, Antibacterial, XRD, Energy band value