Insights into TiO2 thin film photodegradation from Kelvin Probe AFM maps

The synthesis of TiO2 thin films by the chemical spray pyrolysis method at different titanium isopropoxide (TTIP) to acetylacetone (AcacH) ratios has been shown to lead to the highest photodegradation at 1 (TTIP):8 (AcacH). These films hold promise in the field of indoor pollution treatment. Carbon incorporation into the surface and into the TiO2 lattice could be responsible for the observed performance, but the mechanism is still to be elucidated. Here, we report the correlation of contact potential difference (CPD) contrast maps as produced using Kelvin Probe Force Microscopy, and the observed functionality dependence on the TTIP to AcacH ratio. Since the CPD contrast locally provides information about the sample's Fermi level, this correlation provides a means to interpret enhanced photocatalytic activity in terms of the presence of acceptors that make possible a faster transfer of charge carriers to the surface. (C) 2022 Author(s).

Automated summary

The synthesis of TiO2 thin films using chemical spray pyrolysis method with different ratios of titanium isopropoxide (TTIP) to acetylacetone (AcacH) has demonstrated the highest photodegradation at a ratio of 1:8. These films show promise in indoor pollution treatment. The incorporation of carbon into the surface and TiO2 lattice may contribute to the observed performance, but the mechanism is still unclear. Here, the correlation between contact potential difference (CPD) contrast maps and functionality dependence on the TTIP to AcacH ratio is reported, suggesting a faster transfer of charge carriers to the surface.