COLLOIDAL SEMICONDUCTOR PARTICLES AS CHARGE CARRIER GENERATOR MATERIALS
Original Publication Date: 1990-Jun-30
Included in the Prior Art Database: 2004-Apr-05
Xerox Disclosure Journal
Recent work appearing in the scientific literature reports [e.g. R. Rossetti, R. Hull, J. Gibson and L. Brus, J. Chem. Phys. 83, 1406 (1985)] on the novel properties of microscopic colloidal particles formed from semiconductor materials. These properties have been shown to be a consequence of quantum size effects and are reflected by changes in the spectroscopic and photophysical behavior of the particle compared to that of the bulk material. In essence, the spectroscopic transitions and a variety of post-absorption phenomena exhibited by the particles can be tuned by careful control of the particle size. It has been discovered that these colloidal semiconductor particles can be utilized as charge carrier generator materials when the colloidal semiconductor particles are dispersed in a polymer film. The colloid semiconductor can be dispersed in an inert binder to form a separate carrier generator layer whereby the generated charge is injected into a contiguous transport layer or formed directly in a polymer film that is capable of transporting charge carriers injected from the photoexcited colloidal semiconductor. The basic principal involved in tuning the spectroscopic transitions of the semiconductor with particle size is depicted schematically in Figure 1.