The nature of paramagnetic defects in tin (IV) oxide

- EPR signal at g = 1.8-1.9 (D) was studied in SnO2 prepared under different conditions.
- Conditions appropriate for detection of D signal and parameters of them were defined.
- Structure of paramagnetic center (PC) attributed to the D signal was proposed.
- The PC is a complex of oxygen vacancies with entrapped electrons near SnO2 surface.

The nature of paramagnetic centers which are responsible for the EPR signal at g = 1.8-1.9 in tin (IV) oxide was studied. Polycrystalline SnO2 samples were obtained by sol-gel method and by thermal treatment of the precursors containing tin atoms in different oxidation states. The parameters of the EPR spectra recorded after heat treatment of the samples in air, oxygen and hydrogen atmospheres, and in vacuum were analyzed. The observed parameters of the EPR spectra do not allow to assign the paramagnetic center with g = 1.8-1.9 to Sn3+ center. The structure of the paramagnetic center attributed to the EPR signal at g = 1.8-1.9 was proposed. The proposed structure of the paramagnetic center includes a complex of oxygen vacancies at (1 0 1) plane of rutile-type SnO2 lattice.

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