Photocatalytic Coatings Based on TiOx for Application on Flexible Glass for Photovoltaic Panels

Abstract

In this work, the photocatalytic properties of thin films based on titanium oxides for application on flexible glass in photovoltaic panels were presented. Thin films were prepared by gas impulse magnetron sputtering (GIMS), where the gas injection on a target was synchronized in time with the electric pulse supplying the magnetron with the Ti target. The deposition process was carried out under various Ar/O2 atmospheres (with a content of 5–8% O2). The as-deposited TiOx films were non-stoichiometric. The influence of deposition parameters on optical properties, microstructure, hardness, and elastic modulus was examined. In addition, the dependence between the oxygen content in the sputtering atmosphere and the photocatalytic activity of the coatings was examined. The scratch resistance of the coatings and their adhesion to flexible glass were also investigated. It has been shown that the GIMS technique can be used for efficient deposition of non-stoichiometric TiOx coatings on substrates sensitive to the temperature as thin flexible glass and, at the same time, characterized by high adhesion. The TiOx-based semiconductor coatings prepared in this study can be used successfully in transparent electronics and in the construction of modern photovoltaic panels due to their photocatalytic activity, high hardness, and high level of transparency.

A Coaxial Nozzle Attachment Improving the Homogeneity of the Gas Flow Sputtering

“…Indeed, the refractive index is known to correlate with TiO 2 density which increases with oxygen deficiency [45,46]. The absorption index k was found to be lower (0.00639) for titania deposited using the nozzle compared to the ordinary one (0.00917) in the frame of the optical model (see Figure 5b), which supports the suggested difference in the oxygen stoichiometry sample [47][48][49][50]. In sum, the nozzle attachment increased the homogeneous area of titania films from 3 cm 2 to more than 12 cm 2 and allowed to strongly decrease the reactive gas consumption.…”

Optically Transparent TiO2 and ZnO Photocatalytic Thin Films via Salicylate-Based Sol Formulations

“…and λ is the transmitted light wavelength. Thus, for the optically coherent thin films T m is obtained by applying Equation ( 18) on the S 11 element, returned by the system transfer matrix in Equation (15).…”

“…Typically, highly efficient TiO 2 and ZnO coatings are in the form of thick mesoporous layers to maximize their specific surface area [14]. However, these mesoporous coatings may not be practical for applications requiring functional photocatalytic layers with intrinsic optical transparency, such as selfcleaning and antifogging coatings on windowpanes or photovoltaics [15][16][17].…”

“…Transparent TiO 2 and ZnO layers can be fabricated through a variety of deposition methods. Vacuum-based physical vapor deposition (PVD) techniques, such as reactive magnetron sputtering [15,[17][18][19], are commonly favored, however, they can be cost-prohibitive and require specialized equipment and expertise, making them less suitable for smallscale applications. As a result, wet-chemical methods, particularly the sol-gel-based techniques, are preferred, especially in research-scale applications, due to their simplicity, cost-effectiveness, and ability to deposit films without the need for high-vacuum conditions [16,20,21].…”