can be converted into electrical energy. They are also called Grätzel cells after their inventor. In contrast to classical photovoltaics, the conversion of light into electrical energy in dye-sensitized solar cells is not based on semiconductors, but on organic dyes such as chlorophyll. The efficiency of
dye-sensitized solar cells is relatively low, at just a few percent in practice. It was not until synthetic dyes were used that this could be increased to up to 10 %. However, the technology has the advantage that it can be used flexibly on buildings or on moving products. In terms of construction, Grätzel cells consist of two electrodes, the anode and the cathode, which are spaced a few micrometers apart. The two electrodes are thinly coated. The coating of the anode consists of a thin layer oftitanium dioxide and a light-sensitive dye layer on top. When exposed to light, this layer emits electrons from the dye molecules, which are absorbed by the titanium dioxide layer. The positive ions migrate to the cathode. This creates an electrical voltage between the anode and cathode.