Several emerging energy technologies require flexible and solution-processable organic-based electronic materials capable of specific degrees of charge transport in order to achieve desired functions. The range of materials (and applications) is quite diverse, as exemplified by new materials that can facilitate photovoltaic, light emitting or transistor behavior. The molecular requirements necessary to achieve these functions vary greatly, and this lecture will highlight fundamental structural considerations relevant to the design of materials that can foster or otherwise regulate efficient energy/charge migration. One aspect involves the use of unusual aromatic building blocks with relatively low degrees of resonance stabilization that can encourage the intramolecular electronic delocalization of charge carriers. Another aspect deals with alternative ways to control intramolecular delocalization of polymer charge carriers through “evolved aromaticity.” A final aspect involves the control of intermolecular electronic delocalization through the use of water-soluble oligopeptides attached to pi-conjugated oligomers that self-assembly into fibrillar bioelectronic nanostructures containing internal pi-stacked electronic conduits. In all cases, the making, breaking and stacking of aromatic rings is of utmost importance.
J. D. Tovar, “Supramolecular construction of optoelectronic biomaterials,” in the Accounts of Chemical Research 2013, 46, 1527-1537.
B. C. Streifel, P. A. Peart, J. F. Martinez-Hardigree, H. E. Katz and J. D. Tovar, “Torsional influences within disordered organic electronic materials based upon non-benzenoid 1,6- methanoannulene rings,” Macromolecules 2012, 45, 7339-7349.
A. Caruso Jr., M. A. Siegler and J. D. Tovar, “Synthesis of functionalizable boron-containing pi-electron molecules that incorporate formally aromatic fused borepin rings,” Angew. Chem. Int. Ed. 2010, 49, 4213-4217.
A. M. Fraind and J. D. Tovar, “Comparative survey of conducting polymers containing benzene, naphthalene and anthracene cores: interplay of localized aromaticity and polymer electronic structures,” J. Phys. Chem. B 2010, 114, 3104-3116.