Synthesis of Organic Colorants  
Organic NIR Colorants
Unsymmetrical Squaraine and Heptamethine Dyes
Cyanine Dye Polyelectrolytes

Organic NIR Colorants


We synthesize new organic dyes (cyanines) for the application in solar cells. Via chemical modification of these dyes it is possible to alter their optical properties and to optimize their redox behavior.
The target of our research is to absorb light of the Near-Infrared region (NIR) and to transform it efficiently into electrical energy.


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 around 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 the recent years out of dye-sensitized solar cells,
and their efficiencies quickly increased from 10% to over 17% (year 2014). 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
Symmtrical 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



Ihre Ansprechpersonen:


UNESP (Universidade Estadual Paulista, Bauru, Brasilien)

Prof. Carlos F. O. Graeff



Brazilian Swiss Joint Research Programme (BSJRP) – No. BJRP 0112-05
“Organic thin film solar cells based on near infrared absorbing colorants”


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