  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 the
requirement for such a material is that the exciton delocalization in the
system be large, such that the optical gap is small. We develop a theory of
exciton delocalization in conjugated polymers, and show that the extent of this
can be predicted from the topology of the conjugated polymer in question. We
determine the precise structural characteristics that would be necessary for
light emission in the IR.
