Organic NIR Colorants

We synthesize new organic dyes (cyanines) for applications in solar cells, photodetectors and light-emitting electro-chemical cells. Via chemical modification of these dyes it is possible to alter their optical properties and to optimize their redox behavior.

Due to the fact that cyanine dyes are cations, their properties can also be influenced by the choice of different counterions. In collaboration with the research group of Prof. Dr. Carlos F. O. Graeff from UNESP (São Paulo State University, Bauru, Brazil) we examined the influence of the counterions on different properties of the dyes (optical, electrochemical, thin film formation, etc.), as well as on the efficiency of organic solar cells.

A new field of research in our group is the development of efficient perovskite solar cells. These solar cells have been developed in recent years out of dye-sensitized solar cells, and their efficiencies quickly increased from 10% to over 20% (year 2016). Our goal is the development of new hole conducting materials for these solar cells.

Dyes in vials

trisphat crystal structure


Near Infrared Absorbing Colorants with Application in Light to Energy Conversion
Symmetrical Heptamethine Dye (Poster)



Véron A.C., Zhang H., Linden A., Nüesch F., Heier J., Hany R., Geiger T.

NIR-Absorbing Heptamethine Dyes with Tailor-Made Counterions for Application in Light to Energy Conversion

Organic Letter 16(4) (2014) 1044–1047