Benchmarks and applications of novel density functionals to semiconducting polymers

Semiconducting polymers show substantial promise as the active ingredients in inexpensive, flexible, processable ``plastic electronics'' and ``plastic solar cells.'' The difficulty and expense of polymer synthesis makes computational prescreening of novel polymer candidates essential for guiding experiment. Density functional theory (DFT), particularly using hybrid exchange-correlation functionals, has been broadly applied to modeling isolated polymer chains. However, these functionals can be formally and computationally problematic for bulk polymers associating via noncovalent interactions. Screened hybrid and ``Rung 3.5'' density functionals, particuarly their dispersion-corrected variants, show promise for ameliorating these limitations. This work presents benchmarks of these new functionals for this problem, and applications to novel conjugated and nonconjugated semiconducting polymers.