GB378457A - Improvements relating to photo-electric devices - Google Patents

Abstract

378,457. Light-sensitive cells. NAAMLOOZE VENNOOTSCHAP PHILIPS' GLOEILAMPENFABRIEKEN, 13D, Emmasingel, Eindhoven, Holland. May 9,1931, No. 13818. Convention date, May 10, 1930. [Class 40 (iii).] One electrode consists, at least in part, of a photo-electric substance separated from the other electrode by a layer containing one or more solid materials which are semiconductors of electricity, both electrodes and the intermediate layers being supported on one another. The cell will operate without the application of a potential to the electrodes. The photo-electric substance may be caesium, barium or other alkali or alkaline earth metal. The intermediate layer may consist of a compound of one of the metals forming the electrodes, and the photo-electric layer is preferably very thin and adsorbed in the intermediate layer. Particles of alkali or alkaline earth material may be incorporated in the intermediate layer. In the cell shown, the electrode 3 consists of a plate of silver previously coated on one side with a layer 6 of silver iodide. After evacuation, barium is distilled from barium oxide on a heated zirconium filament 8 and forms a deposit 12 on the layer 6. The sensitivity may be increased by heating the cell so as to cause a part of the barium to penetrate into the intermediate layer. The filling may be an inert gas or vapour. In another cell the electrode 3 is of copper, the intermediate layer of copper oxide, and the electrode 12 of caesium. Absorption of caesium may be increased by coating the intermediate layer with caesium oxide ; or an adsorbing substance may be mixed with its intermediate layer. Reference has been directed by the Comptroller to Specification 372,392.