The scientific work carried out led to completion of three main achievements. Firstly, the synthesis of three porphyrin based sensitisers was carried out, this was done using traditional wet lab synthesis and products were characterised according to good practices set out by leading academic journals. The porphyrins were further tested for their photophysical properties; meaning we could test a variety of energy capture ranges, along with energy transfer characteristics and then decide on which was the most efficient in our system overall. Secondly, we used steady state and time-resolved spectroscopy to understand the efficiencies of our trimeric blend for upconversion. We did this by taking the quantum yield of emission when the trimeric blend is present and when only two components are present. We found that a Hetero-annihilation mechanism in the trimeric blend led to higher efficiencies and a greater energy upconversion at low photon flux, but as the photon flux is raised the traditional Homo-TTA mechanism becomes dominant. This result is the first time this has been conclusively demonstrated experimentally. Finally, the last piece of the puzzle was to model the path of photons/electrons in the trimeric blend computationally. This was carried out in collaboration from an expert group working in the Netherlands. Monte-Carlo simulations of TTA systems are few and far between, and to the authors knowledge have never been done for solid state systems. The computational simulations were a success, matching with the experimentally observed results and are the first example of this technique being successfully implemented for trimeric TTA blends. We have little doubt there will be a great interest in the field to use the developed simulations.
