Towards Soluble, Low-Band Gapπ-Conjugated Polymers

Significance

Ogawa and Rasmussen prepared soluble poly(dithienopyrrole)s (polyDTPs) by modifying the standard chemical polymerization conditions. The route was made practical with the efficient monomer synthesis reported previously by these authors (K. Ogawa, S. C. Rasmussen J. Org. Chem. 2003, 68, 2921-2928). Thin films of polyDTPs exhibit electrochromism, appearing red in the neutral state and blue in the oxidized state. Additionally, these polymers emit red fluorescence (˜610 nm) with reasonable quantum yields (˜30%) making them suitable for both OLEDS and sensors. Importantly, by comparing the spectroscopic properties with the carbocyclic analogue the authors demonstrated that the fused nitrogen affords negligible changes to the band gap (˜1.7 eV).