Formation of porous SnO2 by anodic oxidation and their optical properties

Porous anodic tin oxides were constructed via anodic oxidation of tin foils at room temperature. The optimal conditions for the porous anodic tin oxide growth has been explored based on the voltage-, oxalic acid concentration-, and time-dependent reactions. The formation mechanism of the porous anodic tin oxide film is also discussed. Raman spectra show an abnormal Raman peak at 693 cm−1 which is attributed to the IR-active A2uLO mode for the disorder of tin oxide with nanochannels. A broad photoluminescence emission band centered at 600 nm is disclosed to originate from the electronic states determined by the oxygen vacancies.