Electrochemical Formation of Amorphous Selenium Films Doped by Lead Selenide Nanoparticles

The formation of amorphous Se films doped by PbSe nanoparticles during the cathodic co-deposition of Se and Pb is studied. Doping Se with PbSe makes the charge transfer more efficient both in the film bulk and at the heterojunction with electrolyte, thus making it possible to deposit Se(PbSe) films a few micrometers thick. Co-deposition of Se and Pb results from electrodeposition of adsorbed Pb atoms on surface atoms of Se at potentials more positive than the equilibrium potential of the Pb reduction (underpotential deposition). For the Se(PbSe) electrodes, spectral sensitization of photocurrent is observed up to 900 nm. As opposed to Se, which is characterized by absorption at λ < 600 nm, the edge of optical absorption of Se(PbSe) is displaced towards the long-wave region of the spectrum. The underpotential deposition on the Se(PbSe) surface is possible in dark, permitting their additional modification by PbSe monolayers.