We present the synthesis of novel conjugated polymer–porphyrin complexes for use in organic electronics. Linear and star-shaped platinated porphyrins were attached to regioregular poly(3-hexylthiophene-2,5-diyl) (P3HT) arms to investigate whether porphyrin stacking and increased dimensionality can be used to control polymer morphology. The novel materials display similar optical properties to P3HT, but give higher mobilities when used in organic field-effect transistors. Atomic force microscopy measurements show that incorporation of only a small amount of porphyrin into the conjugated polymer backbone leads to increased aggregation. These materials demonstrate that polymer morphology and performance can be tuned and enhanced effectively through the use of conjugatively linked porphyrins.

The synthesis and characterization four diketopyrrolopyrrole containing conjugated polymers for use in organic photovoltaics is presented. Excellent energy level control is demonstrated through heteroatomic substitution whilst maintaining similar solid state properties as shown by X-ray diffraction and atomic force microscopy. Inverted solar cells were fabricated with the best devices having short circuit currents exceeding 16 mA cm⁻² and efficiencies of over 5% irrespective of whether [6,6]-phenyl-C₆₁-butyric acid methyl ester (PC₆₀BM) or [6,6]-phenyl-C₇₁-butyric acid methyl ester (PC₇₀BM) is used. Transient absorption spectroscopy on the bulk heterojunction blends shows efficient charge photo-generation, with the variations in short circuit current correlated to the energetic offset between polymer and fullerene.