TiO2 powder was synthesized in the following way. At first, a colloidal solution of Ti in distilled water was obtained by PLA using Nd:YAG laser (wavelength of 1064 nm, frequency of 20 Hz, pulse duration of 7 ns). Then the colloidal solution was dried at 60 °C. After that, the powder was annealed at different temperatures

Fakhrutdinova, Elena D.

Fedorovich, Zh. P.

Gerasimova, Marina A.

Svetlichnyi, Valerii A.

English

Tomsk State University Repository

Program & Technical Digest Organizer:Hefei Institutes of Physical Science, Chinese Academy of Sciences (CAS)flash talk abstractsStudy of Highly Defective Titanium Dioxide Prepared via Pulsed Laser AblationZ. Fedorovich1, E. Fakhrutdinova1, M. Gerasimova2, V. Svetlichnyi11- Tomsk State University, 36, Lenin Av., 634050, Tomsk, Russia 2- Siberian Federal University, 79, Svobodny A v ., 660041, Krasnoyarsk, Russiazhanna.fedorovich. 99@gmail. comNowadays nanodispersed titanium dioxide is widely used in photovoltaic devices, in the "green technologies" of solar energy, as well as in the production of bactericidal materials and sunscreens [1, 2]. Currently, new technologies are developed to obtain titania-based materials, which absorb light in the visible region and exhibit high photocatalytic activity. We obtained superfine dark blue titanium dioxide with intense absorption in the visible spectral range using pulsed laser ablation (PLA) method [3]. TiO2 powder was synthesized in the following way. At first, a colloidal solution of Ti in distilled water was obtained by PLA using Nd:YAG laser (wavelength of 1064 nm, frequency of 20 Hz, pulse duration of 7 ns). Then the colloidal solution was dried at 60 °C. After that, the powder was annealed at different temperatures.Figure 1 TEM image (a) and photoluminescence spectra (b) o f  TiO2 powder.The initial TiO2 is a dark blue powder (figure 1a) having spesific surface area of 227 m2/g. It consists of the spherical particles with an average size of 5-10 nm, and an insignificant number of large particles with a size up to 80 nm. The initial material is X-ray amorphous, and only after annealing at 400 °C the phases of anatase 67 % and rutile 33 % are formed. Also, after annealing the sample color changes to light grey at 400 ° С and becomes white at 600 ° С. It was found, that TiO2 DRS spectra showed an intense additional absorption in visible region. This is due to the presence of defects of various nature in the structure of TiO2 . The fluorescence bands (figure 1b) in the 380-800 nm region belong to different types of oxygen vacancies (F, F+ and F2+centers) and self-trapped exiton states (STE). It was found that the emission spectrum varies its profile depending on the increase (from 320 to 400 nm) or decrease (from 400 to 320 nm) of the excitation wavelength. This change in the spectrum is associated with a relatively long lifetime of STE states.This work was supported by the Russian Science Foundation, project No. 19-73-30026.[1] M. Noman, M. Ashraf, A. Ali, Synthesis and applications o f  nano-TiO2: a review, Environmental Science and Pollution Research, Vol. 26, pp. 3262-3291, (2019).[2] A. Haider, Z. Jameel, I. Al-Hussaini, Review on: Titanium Dioxide Applications, Energy Procedia, Vol. 157, pp.17-29, (2019).[3] E. Fakhrutdinova, A. Palatova, V. Svetlichnyi, Structure and Optical Properties o f Nanocrystalline Titanium Dioxide Prepared via Pulsed Laser Ablation in Liquid, IEEE Proc., Vol. 2018-July, No. 8434990, pp. 3-7, (2018).86

Study of highly defective titanium dioxide prepared via pulsed laser ablation

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Study of highly defective titanium dioxide prepared via pulsed laser ablation

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