Phenothiazine dye molecular interaction with nanocrystalline TiO2 surface: FTIR and Raman spectroscopy study

AbstractAbstractMolecular interactions of the organic dye phenothiazine with the active sites on polycrystalline anatase and rutile TiO2 surface has been investigated by IR and Raman spectroscopy. It has been shown that, both for anatase and rutile, the interaction of PTZ with TiO2 surface active sites occurs by a spontaneous electron transfer from PTZ to TiO2 with the formation of the PTZ•+ radical-cations, PTZ2+ dications and reduced Ti3+ ions. At the same time, additional oxygen vacancies OV are created on the TiO2 surface which increases the nonstoichiometry of PTZ-sensitized TiO2 compared with the original samples. The appearance of PTZ•+ radical-cations and reduced Ti3+ ions is a reason for the deep blue color of the obtained TiO2/PTZ samples.Keywords: IRphenothiazineRamansurface interactionTiO2 Disclosure statementNo potential conflict of interest was reported by the authors.Additional informationFundingThis work was supported by the National Academy of Sciences of Ukraine under the Target Research Program "Fundamental Physical Processes and Phenomena in Condensed Matter Physics, Optics, Physical Electronics, Nanophysics and Prospects for their Practical Application for New Devices and Materials" (Project no. VC/188), and PAN-NASU Joint Research Project No. 32/2021 "Structural and Spectral Luminescence Properties of Organic Compounds in Nanoporous Media" (2022-2024).