An Aluminum Solid Electrolytic Capacitor with an Organic Semiconductor Electrolyte

This paper describes the development and characteristics of a new aluminum solid electrolytic capacitor in which organic semiconductors are substituted for manganese dioxide. The highly conductive ion-radical salts based on 7, 7, 8, 8-tetracyanoquinodimethan were chosen because of their prominent effect on capacitor self-healing. The solid electrolyte layer of a thin uniform coating was deposited from a solution of the semiconductor and polymers. A basic approach to obtaining a uniform and adherent film suitable for an etched aluminum foil is given, along with limitations on the use of the organic semiconductor. Emphasis is placed on the effect of the polymers on the growth and adsorption of the organic-semiconductor crystals during electro formation. Much improvement was realized in capacitor performance, viz. the Iow leakage current, the extended ratio of breakdown-to-formation voltage, and stable frequency characteristics. It may be concluded from the laboratory experiments that production of high-performance organic semiconductor solid capacitors will probably be feasible in the near future