| abstract |
The present invention relates to a photoactive element, particularly a solar cell, which is composed of an organic layer and has a structure in which one or more pi-type, ni-type, or pin-type diodes are stacked. These diodes are characterized by including at least one p-type or n-type doped conductive layer having an optical band gap larger than that of the photoactive layer. Individual diodes are characterized by high internal quantum efficiency, but can be optically thin (peak absorption <80%). Here, in the present invention, an optical trap is used to lengthen the optical path of incident light in the diode, or a plurality of these diodes are stacked (in this case, using a transition layer for the purpose of enhancing recombination and generation The transition zone between the two diodes can be relaxed), thereby realizing a high external quantum efficiency. In two variations, a series of unique advantages are obtained by using doped conductive layers with large band gaps. |