Brian A Hageman’s research while affiliated with The Graduate Center, CUNY and other places

The protruding oxophilic central metal ion of Zr(IV) porphyrinoids facilitates axial coordination to the oxygen bearing functional groups on graphene oxide (GO) surfaces to result in new supramolecular photonic materials with high dye loading especially on edges and large defects. The reaction proceeds at room temperature with GO dispersed in tetrahydrofuran and GO films on glass. Since the Zr(IV) serves as a conduit, the photophysical properties of the dye sensitized GO derive from both the axially bound chromophores and the GO substrate. Self-organization of metalloporphyrinoids on GO mediated by axial coordination of group (IV) metal ions allows for direct sensitization of graphene and graphenic materials without requiring covalent chemistries with poorly conducting linkers.

Systematic changes in the exocyclic substiution of core phthalocyanine platform tune the absorption properties to yield commercially viable dyes that function as the primary light absorbers in organic bulk heterojunction solar cells. Blends of these complementary phthalocyanines absorb a broader portion of the solar spectrum compared to a single dye, thereby increasing solar cell performance. We correlate grazing incidence small angle x-ray scattering structural data with solar cell performance to elucidate the role of nanomorphology of active layers composed of blends of phthalocyanines and a fullerene derivative. A highly reproducible device architecture is used to assure accuracy and is relevant to films for solar windows in urban settings. We demonstrate that the number and structure of the exocyclic motifs dictate phase formation, hierarchical organization, and nanostructure, thus can be employed to tailor active layer morphology to enhance exciton dissociation and charge collection efficiencies in the photovoltaic devices. These studies reveal that disordered films make better solar cells, short alkanes increase the optical density of the active layer, and branched alkanes inhibit unproductive homogeneous molecular alignment.

A simple, high yield, two-step synthesis yields a porphyrin dimer linked by a flexible dithiol tether that preferentially binds fullerene C(70) over C(60) in toluene solution. The complex forms stable aggregates when cast on glass.

Porphyrins appended with four rigid hydrogen bonding motifs on the meso positions were synthesized and self-assembled into a cofacial cage with four complementary bis(decyl)melamine units in dry solvents. The hydrocarbon chains on the melamine mediate the formation of nanofilms on surfaces as the solvent slowly evaporates.