The direct conversion of sunlight into electricity has been a utopian dream. The ability to generate electricity in this manner is, of course, exciting since it utilizes nondepletable fuel and is nonpolluting. However, since the 1950’s, the approach to accomplish this aim has been primarily through the utilization of expensive crystalline silicon solar cells. We describe here how noncrystalline materials, that is, amorphous materials, can be produced as continuous, large-area, thin-film devices with efficiencies, stabilities, and costs which will permit them, for the first time, to compete realistically with conventional fuels such as oil, gas, uranium, and coal.