Abstract The photoelectrochemical properties of novel GaAs/AlGaAs superlattice electrodes were investigated in nonaqueous solutions containing reversible and irreversible redox couples. The superlattice materials consisted of 35 alternating layers of 17 A Al 0.35 Ga 0.65 As and 150 A GaAs grown onto a highly doped p -GaAs substrate. Under illumination, the superlattice electrodes exhibited current/potential curves with hysteresis in decamethylferrocene +/0 solutions. The hysteresis was due to photoinduced dark current associated with hole injection into the valence band of the semiconductor. More reducing couples such as cobaltocene +/0 and dicarbomethoxycobaltocene +/0 afforded stable current/potential curves with the superlattice electrodes. The irreversible homogeneous and electrochemical reduction of a series of vicinal dibromides was investigated in order to develop a redox system capable of detecting hot electron reactions.