A novel approach toward low optical band gap polysquaraines

[GRAPHICS] Polycondensation of 2,5-dialkoxydivinylbenzene-bridged bispyrroles and squaric acid resulted in extensively conjugated polymers with strong near-infrared (NIR) absorption around 800-1000 nm, which is a signature of their low band gap (E-g). Conjugated polymers with such a strong NIR absorption are rare. One of the synthesized polysquaraines showed a significantly low E-g of 0.79 eV with an intrinsic conductivity of 5.3 X 10(-4) S/cm.