Light Harvesting Single Wall Carbon Nanotube Hybrids

Due to extraordinary electron accepting and conductivity properties, single wall carbon nanotubes (SWNT) are explored as molecular wires in light harvesting cells. Here SWNT are employed as acceptors of photo-excited charge/energy in self-assembling aqueous soluble nanohybrids. DNA oligonucleotides and functionalized pyrene moieties are used as surfactants to solubilize an ensemble of individually suspended SWNT. Water-soluble porphyrins, chlorophyll-like molecules with strong optical signatures in the visible range, are used as donors. These bond with surfactants, pyrene and DNA oligonucleotides via electrostatic and base intercalation, respectively. Alternative structures are presented, studying the effects of SWNT surface chemistry and intermolecular spacing between porphyrin and SWNT sidewalls. A novel structure is developed that employs DNA oligonucleotides as a multi-functional "glue," simultaneously suspending SWNT while exploiting DNA target recognition capabilities to bind with donor porphyrins. Transductions in optical spectra and fluorescence quenching show evidence of charge transfer interactions, offering a novel dynamic and tunable nanomaterial for light harvesting.