(602az) Bioinspired Electrets for Solar Energy Conversion

Protein-mediated electron-transfer processes sustain a broad range of redox functions in biological systems, such as respiration and photosynthesis. Therefore, such biological systems are inspirational models for materials for energy-conversion applications. This presentation will focus on bioinspired macromolecular electrets with rectifying long-range charge-transfer properties. We have demonstrated molecular designs based on anthranilamide derivatives, which similar to polypeptide α-helices, contain ordered arrangement of amide and hydrogen bonds, but in contrast to polypeptides and proteins, have an extended Π-electronic conjugation for mediating efficient long-range charge transfer. Ab initio calculations, along with dielectric and NMR measurements, revealed that polyanthranilamides possess intrinsic dipole moments in the order of 3 D per residue. Furthermore, the macromolecular dipoles remove the degeneracy between the frontier orbitals of neighboring residues, causing splitting of ~0.2 eV for 10 residues that can readily result in rectification of vectorial charge hopping. Doping the macromolecules with electron withdrawing and electron donating groups did not only alter the bandgap and the energy levels of the frontier orbitals, but also modulated the intrinsic dipole moments, ranging from 0 to 5 D per residue. The design of the presented bioinspired electrets will prove instrumental for the development of materials with rectifying charge-transduction properties essential for solar-energy-conversion applications.