Abstract
Energy and electron transfer dynamics dominate the efficiencies of the photosynthetic
processes that drive the natural world. Investigations into the quenching rates in lightharvesting complexes with chromophore-protein bindings of nanometer precision reveal nonlinear trends that are not seen in synthetic systems. Unveiling the processes and determining
factors of these systems would allow for increased efficiencies in light transporting systems
e.g. solar cells, that are at the forefront of modern renewable technologies.
The initial study of this work investigates porphyrin – o-MWCNT complexes displaying
resonant luminescence quenching phenomena. Steady-state and time-resolved luminescence
data as well as DLS particle size data is used to characterise the mechanisms of energy
transfer within the systems. These findings are explored in the context of luminescence
concentration quenching phenomena seen in similar organic and photosynthetic complexes.
Following this, experimental parameters such as solvent polarity and dielectric were utilised
to move and further explore the system’s non-linear luminescence response. The role of the
porphyrin A3B linker is investigated, with protoporphyrin also used as a control experiment.
We display the strength of the electron transfer mechanism within the complexed systems and
compare across the solvent types. In the final experimental chapter the system was applied
to a well-studied topic of hazardous dye photodegradation in aqueous environments. Our
complexes were suitable due to the presence and efficiency of electron transfer within the
complexes. Excitation of porphyrin species and subsequent electron transfer processes could
be utilised in a water-based solvent environment to form reactive oxygen species that can be
used to create less toxic products when used as a photocatalyst to degrade rhodamine dyes
using a solar-like visible spectrum as an illumination source.