Small band gap polymers based upon anti-aromatic monomers

We present a new idea for a route towards small band gap polymers. First pr inciples DFT calculations show that anti-aromatic molecules, such as pental ene and s-indacene, are ideally suited to construct polymers which could ev en be intrinsically metallic. The electronic structure of such polymers is characterized by a band crossing at the Fermi level between a relatively fl at band consisting of nonbonding pi -states and a regular pi -band. Isoelec tronic substitution of CH groups by nitrogen atoms shifts the bands around the Fermi level, creating semiconductors with band gaps close to 1 eV.