The rapidly progressing fields of organic photonics research has led to a renaissance in the chemistry of dye molecules, compelling scientists to revitalize old pigments, transform them into soluble dyes and apply them in the construction of new and complex semiconducting materials. Among other materials (e.g. (iso)indigo, benzodipyrrolidone, benzodifurannone, and others), the dyes based on diketo-pyrrolo-pyrrole (DPP) unit becomes to be highly studied nowadays. Derivatives of 3,6-diphenyl-2,5-dihydro-pyrrolo[3,4-c]pyrrole-1,4-dione, commonly referred to as DPPs, constitute recent industrially important class of high-performance pigments. They are endowed with brilliant shades and exhibit exceptional chemical, heat, light, and weather fastness. If we add to this a large conjugated system, the materials represent an attractive basic core for organic photonics. It has been proved that the DPPs can serve as an efficient structure for organic solar cells materials, can exhibit high p- and n-type mobility and allow for construction of electroluminescent devices.
In this contribution we present the study of the effect of DPP chemical structure on the electrical, optical and optoelectronic properties for photonic applications. We discuss the influence of various substitutions (polar groups, solubilizing groups). These modifications allow fine-tuning of the frontier molecular orbitals, molecular geometries and the resulting optical and electrical properties. We show that these dyes can offer efficient base for optical applications (solid state lasers, two-photon absorption) and optoelectrical applications such as photovoltaics. Model devices were prepared and characterized and the experimental outcomes compared with theoretical results obtained with the help of quantum chemical calculations.
This work was supported by the Ministry of education youth and sport of the Czech Republic, project No. LO1211 and by Czech Science Foundation via project No.13-29358S.