Low Bandgap, Highly Polarizable, and Intrinsically Conductive Polymers
Abstract
This program is directed at the design and synthesis of new classes of polymers with enhanced polarizability, electronic delocalization for electrical transport, photoconductivity, and magnetooptical responses. These properties can enable electronic, photovoltaic, and sensory technologies relevant to the Air Force. To this end, we will develop new synthetic and assembly methods for the synthesis of ladder polymers (nanoribbons). Bond forming strategies for the formation of nanoribbons and chiral assembly into preorganized helical conformations will afford the synthesis of polyhelicene materials that are expected to have pronounced chiro-optical and magneto-optical properties. Materials having sulfur heteroatoms as well as all carbon nanoribbon structures will be examined. Designs will be explored that promote electronic all carbon structures with regions of negative and positive charge. These polar contributions are expected to promote polarizability and when combined with chirality can give rise to large magneto-optical (Faraday effect) responses. Metal thiolate polymers with multiple bridging ligands represent another class of ladder polymer and we will seek to establish initial structure property relationships for this largely unexplored class of compounds. All of the materials will be broadly evaluated based on their material properties. These studies include determination of conductivity and carrier mobilities, with the latter requiring semiconductive behavior to generate field effect transistor data. The predicted high polarizability of these materials will give rise to photoconductivity as a result of spontaneous separation of photogenerated electron-hole pairs. We expect that some of the materials may have very low band gaps or even potentially intrinsic (metallic) conductivity. In metallo-polymers containing paramagnetic metal centers, we will conduct magnetic measurements at room temperature to determine the degree of M---M interactions as a function of...
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jun 11, 2018
- Source ID
- FA95501810341
Entities
People
- Timothy M. Swager
Organizations
- Air Force Office of Scientific Research
- Massachusetts Institute of Technology
- United States Air Force