Tin dioxide thin films prepared from a new alkoxyfluorotin complex including a covalent Sn-F bond

Fluorine-doped tin dioxide (FTO) films were elaborated from a new Sn(IV) molecular precursor, the (tert)amyloxyfluorodipentan-2,4-dionatotin(IV) complex, to be used via the sol-gel route. Upon controlled hydrolysis in acetonitrile, a fluorinated polystannoxane was formed as a stable xerosol, which was characterized by multinuclear magnetic resonance and Mossbauer spectroscopies, elemental analysis, and thermogravimetry coupled to mass spectrometry. This xerosol was further dissolved in acetonitrile for depositing highly transparent films by the spin-coating and spray pyrolysis techniques. Film composition was determined by X-ray photoelectron spectroscopy, electron probe microanalysis and energy dispersive X-ray analysis. The F/Sn atomic ratio was 3% for spin-coated films and 10% for the sprayed films. A noticeable amount of carbon (C/Sn #10 at.%) was detected in the films whatever the deposition technique. In every case, the film resistivity was found to be larger than the one obtained from separate tin and fluorine precursors. This result was attributed to the excess of carbon and fluorine content in the oxide layers relieved from the xerosol. (C) 2001 Elsevier Science B.V. All rights reserved.