Carbon nanostructured based donor-acceptor conjugates for light-induced energy and electron transfer

Abstract

The research presented in this dissertation deals with the syntheses, characterization, electrochemical, computational and photophysical studies of carbon nanostructures such fullerenes, single-wall carbon nanotubes (SWCNT) and highly colored pigment containing donor-acceptor supramolecular assembles. Using these fascinating chromophores, we have designed and synthesized donor-acceptor systems to mimic natural photosynthesis. Photosynthesis involves two major steps, absorption and transportation of light energy to the reaction center, and photoinduced electron transfer (PET) to generate charge separated entities by using the electronic excitation energy. We have designed elegant photosynthetic architectures using fullerene as carbon nanostructure based material for mimicry of antenna, mimicry of reaction center and mimicry of 'combined antenna-reaction center' functionalities in the natural photosynthetic system. Semiconducting single-wall carbon nanotube (SWNT)-based supramolecular nanoarchitectures are constructed using photosensitizing donor and acceptor molecules which reveal efficient photoinduced charge separation. The kinetic and thermodynamic data suggests feasibility of these nanohybrids for the construction of photovoltaic cell and other devices. Interestingly, the photoelectrochemical behavior of the nanohybrids indicates that by choosing nanotubes of appropriate diameter, it is possible to improve the light-harvesting conversion efficiency.