Application of the Gartner model to elucidate parameters adversely affecting photoactivity of thin film PbO in Fe(CN)(6)(3-/4-) electrolyte

A photoactive alpha-PbO phase is synthesized by potentiodynamic anodization of lead (in alkaline medium) in the potential region of -0.75 V to 1.25 V (vs Hg/HgO). The oxide electrode formed after 18 min of anodization shows an energy conversion efficiency of 0.9% with an open circuit voltage of 800 mV and short circuit current of 2.2 mA cm(-2). Mott-Schottky measurement shows that the flat band potential of this photoanode is -0.54 V (vs Hg/HgO) with a donor concentration of 1.14 x 10(16). The influence of variation in space charge layer width, diffusion length and absorption coefficient on the photoactivity of PbO is studied using the Gartner model. It is concluded that low conversion efficiency of the PbO film is due to formation of a small depletion region (3680 Angstrom) and a large diffusion region (2443 Angstrom) as compared to a very large 1/alpha value (14084 Angstrom) at 500 nm. Copyright (C) 199