Semiconductor microcrystals (Q-particles), with diameters less that 100 Angstrom, modified with viologen have recently been produced. One potential application for such particles would be for light energy conversion devices such as photocatalysts and photosensitizers in wet solar cells. The viologen moieties have the ability to function as electron mediators between the semiconductor and accepters in solution. The preparation and potential applications of these interesting materials are discussed.