a semiconductor liquid junction photocell using a photoactive electrode comprising gaas has greatly improved solar energy to electrically conversion efficiency when compared to prior art semiconductor liquid junction photocells using gaas electrodes . the improved efficiency is obtained by material , such as ruthenium , cobalt , rhodium or lead , on the electrode surface . efficiency is still further increased by texturizing the surface of the gaas electrode prior to addition of the material . efficiencies under am1 conditions are approximately 12 percent .