BIFACIAL SOLAR CELL WITH HOLE TRANSPORT LAYER AND MANUFACTURING METHOD FOR THE SOLAR CELL TANDEM SOLAR CELL AND BIPV MODULE USING THE SOLAR CELL

摘要

The present invention relates to a CIGS solar cell with increased efficiency while applying a transparent electrode to upper and lower portions thereof which comprises: a transparent lower substrate; a lower transparent electrode layer of a transparent conductive oxide material formed on the lower substrate; a light absorption layer of a chalcopyrite-based material, formed on a lower transparent electrode; an upper buffer layer formed on the light absorption layer; and an upper transparent electrode layer formed on the upper buffer layer. The light absorption layer has a structure in which a band gap of a lower portion thereof is larger than that of an upper portion thereof, which is a multi-layered structure that a band gap is different or a single structure in which the band gap is continuously changed. Also, a hole transport layer exhibiting hole transport characteristics is inserted into a space between the light absorption layer and the lower transparent electrode layer. The band gap of a lower portion of the light absorption layer corresponding to the lower transparent electrode layer is larger than that of an upper portion to reduce recombination of electron and hole at the lower portion of the light absorption layer and the hole transfer layer is additionally inserted into a space between the light absorption layer and the transparent electrode layer to increase the efficiency between the lower transparent electrode layer of a transparent conductive oxide material and the light absorption layer. Also, the efficiency of a final solar cell is increased by preventing gallium oxide from being formed on an interface.