Structural influence of a dichalcogenopheno-1,3,4-chalcogenodiazole comonomer on the optoelectronic properties of diketopyrrolopyrrole-based conjugated polymers†
We designed, synthesized, and characterized four conjugated polymers (PDPP-T-Odz, PDPP-T-Tdz, PDPP-Se-Odz, and PDPP-Se-Tdz) that are composed of electron-deficient dichalcogenopheno-1,3,4-chalcogenodiazole planar subunits, which show a wide range of UV-Vis-NIR light absorption. A comparison of the characteristics of these polymers that have different spacer units and chalcogen atomic substitutions revealed that the selenophene spacer boosts the hole and electron mobilities, and that the chalcogen atomic substitutions affect the polarity of the charge carriers. As a result, polymer transistors based on polymers that incorporate selenophene spacers showed hole and electron mobilities of up to 0.04 and 0.03 cm2 V−1 s−1, respectively. These results suggest that the diselenopheno-1,3,4-oxadiazole and diselenopheno-1,3,4-thiadiazole units are promising building blocks to achieve high-performance optoelectronic materials that have high carrier mobility.