Some of photoelectric conversion devices that are used in, for example, solar power generation each comprise a light absorption layer formed of a group compound, such as CIS and CIGS, or a group I-II-IV-VI compound, such as CZTS. These photoelectric conversion devices are described in, for example, Japanese Unexamined Patent Application Publication No. 2000-299486 and Japanese Unexamined Patent Application Publication No. 2007-269589.
The photoelectric conversion device comprising such a light absorption layer has a structure composed of a plurality of photoelectric conversion cells arranged in a planar form. The photoelectric conversion cells are each composed of a lower electrode such as a metal electrode, a photoelectric conversion layer including a light absorption layer or a buffer layer, and an upper electrode such as a transparent electrode or a metal electrode layered in this order on a substrate such as a glass substrate. The photoelectric conversion cells are electrically connected in series by electrically connecting the upper electrode of one of two adjacent photoelectric conversion cells to the lower electrode of the other photoelectric conversion cell with a connecting conductor.
The photoelectric conversion device is always required to be improved in the photoelectric conversion efficiency. The photoelectric conversion efficiency is the ratio of conversion from solar energy into electrical energy in a photoelectric conversion device and is derived by, for example, dividing the electrical energy value output from a photoelectric conversion device by the solar energy incident on the photoelectric conversion device and multiplying the result by 100.
Japanese Unexamined Patent Application Publication No. 2000-299486
Japanese Unexamined Patent Application Publication No. 2007-269589