Abstract: A photovoltaic cell having an electrically conductive substrate, which may be glass having a film of conductive tin oxide; a first layer containing a suitable semiconductor, which layer has a first component film with an amorphous structure and a second component film with a polycrystalline structure; a second layer forming a heterojunction with the first layer; and suitable electrodes where the heterojunction is formed from a solution containing copper, the amorphous film component is superposed above an electrically conductive substrate to resist permeation of the copper-containing material to shorting electrical contact with the substrate. The penetration resistant amorphous layer permits a variety of processes to be used in forming the heterojunction with even very thin layers (1-6.mu. thick) of underlying polycrystalline semi-conductor materials.

Abstract: A large area photovoltaic cell comprising a layer of multicrystalline cadmium sulfide, about 1 to 2 microns thick, formed by simultaneously spraying two suitably selected compounds on a uniformly heated plate of Nesa glass, thereafter forming a coating of Cu.sub.2 S over the cadmium sulfide layer while the latter is heated, to form a photovoltaic heterojunction, applying thereover a layer of CuSO.sub.4, and applying electrodes of Cu and Zn, respectively, to separated areas of the layer of CuSO.sub.4, and heating the cell to form a cuprous oxide rectifying junction under the copper electrode by reaction of the Cu electrode with the CuSO.sub.4, while diffusing the zinc through the body of the cell. The diffusion of the zinc provides a negative electrode coplanar with the positive copper electrode, eliminating any need for introducing mechanically complex provision for making a connection to the Nesa glass, while the use of a CuSO.sub.

Abstract: A method of forming a cadmium sulfide film from a solution containing a cadmium salt and a sulfur containing compound comprising inclusion of a chlorine containing compound in the solution utilized to form the cadmium sulfide film.

Abstract: A method of making low cost photovoltaic cells on a large scale basis by means of a continuous process of coating sheet glass while the sheet glass moves in and has its under surface immersed in a tank of molten material, comprising forming the film of CdS microcrystals on the glass sheet, which has previously been coated with transparent SnO.sub.x to a thickness of about 0.3 to 0.6 microns. A water solution of a cadmium salt, a sulphur compound, and an aluminum containing soluble compound is intermittenty sprayed on said glass while its exposed surface is maintained at a constant temperature in the range 500.degree. F to 1100.degree. F and while irradiating the surface with intense ultraviolet light so as to form a film of CdS microcrystals. This CdS film has Al impregnated within the stratum of the film adjacent to the SnO.sub.x, but only optionally has Al impregnated in the stratum of the CdS film adjacent to the exposed surface of the CdS film.

Abstract: A selective corona charger is disclosed for imparting an electrical charge to liquid droplets in a spray, comprising conductor means, means for defining a grid, a means for moving the conductor means in the grid, scraper means for cleaning excess spray off the conductor means, and a power source for imparting a high voltage to the conductor means. The droplet charger is placed between the source of the spray and the article being sprayed. In operation, the article being sprayed is held at a low electrical potential, preferably ground. The spray is directed toward the article being sprayed and as the spray droplets pass through the corona charger they receive a high electrical potential or charge from the corona charger. The droplets are thereafter electrically attracted to the article being sprayed.

Abstract: A large area photovoltaic cell comprising a layer of multicrystalline cadmium sulfide, about 1 to 2 microns thick, formed by simultaneously spraying two suitably selected compounds on a uniformly heated plate of Nesa glass, thereafter forming a coating of Cu.sub.2 S by spraying two suitable compounds over the cadmium sulfide layer while the latter is heated, to form a photovoltaic heterojunction, applying thereover a layer of CuSO4, and applying electrodes of Cu and Zn, respectively, to separated areas of the layer of CuSO.sub.4, and heating the cell to form a cuprous oxide rectifying junction under the copper electrode by reaction of the Cu electrode with the CuSO.sub.4, while diffusing the zinc through the body of the cell.