Materials synthesis strategies for: Microstructure self-assembly, polymer-encapsulated reverse micelles, ionic donors in bimolecular photosystems, and efficient mediators in dye-sensitized solar cells.

摘要

Materials synthesis strategies have been applied to a number of projects in a variety of research fields. First, the synthesis of an amine-functionalized monomer that forms a conducting polymer was used to produce a material that could easily be used in template-synthesis to produce micro- and nanostructures. These amine-functionalized structures were employed to investigate the use of avidin-biotin technology for self-assembly. The successful self-assembly of micro- and nanoparticles to microfibers and microtubes is reported.; Second, reverse micelles were used to direct the phase segregation of a polar dye solution in a non-polar monomer. Polymerization of these mixtures resulted in encapsulation of the reverse micelles. Solid monolithic samples of optical quality that exhibit solution-state photophysical properties were obtained. The development and characterization of these materials is discussed in detail.; Third, a number of ionic derivatives of phenothiazine were synthesized and investigated as electron donors in bimolecular photosystems. These systems were characterized by transient absorption spectroscopy under the same conditions used to study non-ionic phenothiazine donors. The results of these studies are compared to previous results. Additionally, a mixed salt of a cationic chromophore-acceptor diad and an anionic phenothiazine was metathesized and sequestered in the core of reverse micelles. The photophysics of this system was studied in the presence and absence of a magnetic field, and found to retain magnetic field-affected recombination kinetics similar to covalently-linked donor-chromophore-acceptor triads.; Finally, alkyl-substituted polyimine complexes of cobalt(II) and cobalt(III) were discovered to act as efficient electron-transfer mediators in dye-sensitized solar cells. A series of complexes encompassing a wide range of thermodynamic, structural, and steric characteristics was synthesized. This was accomplished through the use of polyimine ligands appended with electron-donating or electron-withdrawing substituents having a variety of steric requirements. The spectral properties and electrochemical behavior of the corresponding complexes were studied. Comparison of the electrochemical results with the performance of dye-sensitized solar cells containing cobalt complex-based mediators revealed empirical trends that could be used to identify potentially efficient mediators. A detailed discussion is presented on these findings as well as on the photoelectrochemical performance of optimized cobalt complex-mediated cells.