HIGHLY EFFICIENT SELENIUM HETERO JUNCTION SOLAR BATTERY

摘要

A photocell includes a metallic base electrode, a continuous, crystalline P-type semiconductive selenium layer less than about 50 microns thick, a thin tellurium layer interposed therebetween to metallurgically bond the base electrode to the selenium layer and to form an ohmic contact between the base electrode and the selenium layer, a thin N-type semiconductive cadmium selenide layer contiguous with the selenium layer and forming a photovoltaic heterojunction therebetween, a pellucid layer of at least one cadmium chalcogenide contiguous with the cadmium selenide layer and forming an ohmic contact therewith and a current collecting electrode on the cadmium chalcogenide layer. The sunlight conversion efficiency of the cell is at least about 3.0%. The efficiency can be further improved by doping the selenium layer to improve its conductivity and by providing an N-type layer of cadmium selenide and N+cadmium oxide. This can be done by continuously varying the oxygen content of the N-type layer. It is further helpful if a counterelectrode in the form of a grid is added, which minimizes both the resistance between the grid members in the cadmium layer and the blockage of light by the grid.