Atmospheric Pressure Deposition of Fluorinedoped SnO2 Thin Films from Organotin Fluorocarboxylate Precursors.

Abstract

Nine organotin fluorocarboxylates RnSnO2CRf (n = 3, R = Bu, Rf = CF3, C2F5, C3F7, C7F15; R = Et, Rf = CF3, C2F5; R = Me, Rf = C2F5; n = 2, R =Me, Rf = CF3) have been synthesised; key examples have been used to deposit F-doped SnO2 thin films by atmospheric pressure CVD. Et3SnO2CC2F5, in particular, gives high quality films with fast deposition rates despite adopting a polymeric, carboxylate-bridged structure in the solid state, as determined by x-ray crystallography. Gas phase electron diffraction on the model compound Me3SnO2CC2F5 shows that accessible conformations do not allow contact between tin and fluorine, and that direct transfer is therefore unlikely to be part of the mechanism for fluorine incorporation in SnO2 films. The structure of Me2Sn(O2CCF3)2(H2O) has also been determined and adopts a trans- Me2SnO3 coordination sphere about tin in which each carboxylate group is monodentate