Designing pi-conjugated polymers with light emission in the infrared

There is currently a great need for solid state lasers that emit in the infrared. Whether or not conjugated polymers that emit in the IR can be synthesized is an interesting theoretical challenge. We show that emission in the IR can be achieved in designer polymers in which the effective Coulomb correlation is smaller than that in existing systems. We also show that the structural requirement for having small effective Coulomb correlations is that there exist transverse $\pi$--conjugation over a few bonds in addition to longitudinal conjugation with large conjugation lengths.