Organic thin-film photoelectric conversion element and method of manufacturing the same
The objectives of the present invention are to enable the manufacturing of an organic thin-film photoelectric conversion element under normal atmosphere, improve the photoelectric conversion efficiency of the element, and enhance its durability. A hole-blocking TiO2 layer is created between the photoelectric conversion layer and the electrode by a wet process. In the manufacturing process, the hole-blocking TiO2 layer is air-dried so that it will be an amorphous layer. It is possible to provide a concentration gradient layer of PCBM/P3HT in which the PCBM concentration is higher in a region close to the hole-blocking TiO2 layer. This structure will reduce the electric resistance of that region and minimize the current loss within the photoelectric conversion element.
In the vicinity of the hole-blocking TiO2 layer, the PCBM concentration is increased, which in turn makes it easier for electrons to flow into the TiO2 layer since PCBM is electrically conductive. Due to these features, the organic thin-film photoelectric conversion element having the gradient structure of the present embodiment has a high level of photoelectric conversion efficiency and good durability.