Spectroelectrochemistry of highly doped nanostructured tin dioxide electrodes

A new, highly doped nanostructured SnO2:Sb electrode has been prepared. This electrode possesses characteristics markedly different from undoped nanostructured semiconductor electrodes. Cyclic voltammetry and spectroelectrochemical experiments reveal that the whole of the nanostructured SnO2:Sb electrode is electronically addressed in a potential range extending from negative to significantly positive of the flatband potential. The flatband potential of nanostructured SnO2:Sb, obtained from the Mott-Schottky analysis, shows Nernstian dependence on pH and is given by +0.10 - (0.06)(pH) (V vs Ag/AgCl). The extinction coefficient for conduction band electrons is determined to be 2400 M-1 cm(-1) at 700 nm. A theoretical model, based on; expressions derived for spherical semiconductor particles, fully accounts for the observed capacity-potential relation.