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) mo lecular precursor, the (tert)amyloxyfluorodipentan-2,4-dionatotin(IV) compl ex, to be used via the sol-gel route. Upon controlled hydrolysis in acetoni trile, a fluorinated polystannoxane was formed as a stable xerosol, which w as characterized by multinuclear magnetic resonance and Mossbauer spectrosc opies, elemental analysis, and thermogravimetry coupled to mass spectrometr y. 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 p robe microanalysis and energy dispersive X-ray analysis. The F/Sn atomic ra tio was 3% for spin-coated films and 10% for the sprayed films. A noticeabl e amount of carbon (C/Sn #10 at.%) was detected in the films whatever the d eposition technique. In every case, the film resistivity was found to be la rger than the one obtained from separate tin and fluorine precursors. This result was attributed to the excess of carbon and fluorine content in the o xide layers relieved from the xerosol. (C) 2001 Elsevier Science B.V. All r ights reserved.