Abstract
Photocurrent at SnO2/Rhodamine B (aqueous solution) interface was measured at various pH. It became apparent from the time dependence of photocurrent that after photoanodic process the dark cathodic process (D++e-→D) occurred by tunneling through the space charge layer. The reverse cathodic current decreased with increase of pH. Photocurrent due to the photoelectrochemical reaction was detected by using high pH solution and lock-in amplifier. Photocurrent vs. electrode potential characteristics can not be interpreted by the electron transfer theory considering only solvent polarization.
