Some specific features of spectral, electrochemical and energy characteristics of the polymethine cationic dyes-sensitizers

Abstract

The sensitization of semiconductors to a broader light spectral range is an important direction in the design of photosensitive semiconductors. However, the method of sensitization, which involves the direct addition of dyes to the reacting mixture, has some disadvantages. First, the adsorption of dye is comparatively weak, while its solubility in the reacting mixture is much higher. Because of that, the dye concentration in the mixture should be kept high, which makes unwanted inner light filtering more intense. This problem can be fixed by developing special heterostructures consisting of a layer of the dye-sensitizer applied to the surface of a semiconductor and protected by a special polymer film. This film doesn’t put any obstacles to the interphase electron-exchange processes and prevents the dye from being washed off. Polymethine dyes are very efficient sensitizers to be used in such heterostructures and are widely used in photocatalysis and technologies for solar light conversion and accumulation.