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John D. Tovar
Johns Hopkins University Phone: 410.516.4358 PhD - Massachusetts Institute of Technology The Tovar group has broad interests in organic electronic materials, particularly the study of unusual chromophores and unusual chromophore orientations. We will use molecular design as a tool to predict, control and seek a better understanding of charge mobility and conductivity through organic electronic materials and apply this knowledge to emerging applications ranging from inexpensive flexible circuitry to active biomedical materials. Members of my research team will gain extensive experience in organic synthesis (aromatic, polymer and peptide chemistries), exposure to optical and electrochemical characterization techniques, and opportunities to participate in multi-disciplinary research collaborations. Unusual aromaticity and charge transport. Cyclic pi-conjugated molecules have provided a wealth of information on the concept of aromaticity, yet difficult syntheses have limited their widespread application. We are interested in the synthesis and characterization of elaborate molecular and polymeric scaffolds with unusual electronic properties such as weak and evolved aromaticity. These studies will reveal how weakly aromatic segments may facilitate charge injection into and transport through conducting polymers while enhancing their environmental stability. Optoelectronic plastics. Organic electronic materials are often employed in specialized niche markets or remain limited to small-scale production. One solution to this problem involves rendering conjugated oligomers compatible with addition or chain-growth polymerizations to enable synthetic scale-up and easier processing (for example, segmented polyurethanes, block copolymers and hyperbranched polymers). Parallel efforts involve studying photochromic polymers that can attenuate electrical conductivity via indirect alterations of the conjugated backbone. This research will help transition value-added organic monomers into commodity polymers relevant for light emission and charge transport applications on scales beyond the benchtop. Spatial chromophore engineering: Molecular and bio-inspired platforms. Studies of organic electronic materials in solution often do not translate adequately to the solid state due to the dominating influence of chromophore aggregation and other non-specific interactions. We have interests in molecular scaffolds designed to enforce particular orientations of conjugated oligomers while frustrating crystallization and aggregation. Self-assembling peptides are also being designed to direct the controlled aggregation of conjugated organics thus yielding unusual biomimetic surface modifications or electroactive fibrils at size regimes (10-30 nm) unattainable through polymer processing or current lithographic techniques. The peptides will serve as insulating dielectrics while enabling cellular interactions that rely on oligopeptide epitope recognition. |
