Photocurrent instability of PbS-sensitized TiO₂ electrodes in S^2- and SO₃^2- solution

The mechanism of photocurrent decay with time of illumination of PbS-coated TiO₂ (PbS/TiO₂) photoelectrochemical cells in S^2- and SO₃^2- solution was investigated. The photocurrent decay at short circuit can primarily be attributed to the formation of PbSO₄ on the surface of PbS, followed by the dissolution of PbSO₄ into the aqueous solution. In the presence of pyridine or ethanol in the solution, the J_sc decay with time of illumination is reduced due to the suppression of the PbSO₄ formation.