This project will provide a PhD training regimen in advanced spectroscopy and chemical synthesis, which will lead to multiple REF returnable outputs.
Photochemistry, in which visible or ultraviolet light is used as a catalyst to promote the formation of new chemical species with distinct chemical properties, is of growing importance for molecular synthesis, therapeutic diagnostics and new technological applications such as light emitting diodes. Absorption of light energy frequently involves the creation of paramagnetic excited states or charge carriers that play vital roles in electron transfer events, displaying significantly different chemistry to ground state processes. However, these species often evade detection due to their incredibly short lifetimes.
Dr Richards has recently secured external funding to support the development of a new facility in Time-Resolved Electron Paramagnetic Resonance (TR-EPR) spectroscopy, to interrogate short-lived photo-induced paramagnetic species. Dr Richards will apply TR-EPR methods to yield accurate resolution of kinetics, molecular profiles, and structural models which cannot be accessed under steady-state conditions due to rapid relaxation processes.
TR-EPR will provide fundamental knowledge of charge transport mechanisms required for the optimization of efficient photosynthetic systems and devices.
Photon upconversion by Ir(III) complexes
Photon upconversion has received significant attention as a means of increasing the efficacy of light harvesting processes, photoredox catalysis and for bioimaging agents. SJAP has recently demonstrated leading conversion efficiencies using novel Ir(III)-based donor:acceptor systems through triplet-triplet upconversion (Chem. Eur. J. 2018). TR-EPR is ideally suited to fully disentangle the spin interactions of the photoexcited system (e.g. transient organic triplets, spin-orbit coupling parameters), results guiding rational design of donor:acceptor pairs for maximum upconversion and selective emission wavelengths.
Sustainable sensitizers for dye-sensitized semiconductor solar cells.
Photoexcitation of metal oxide semiconductors creates charge carriers that can be utilised in surface redox processes and in electrical thin-film devices. ER/DMM have recently provided unique insights into this area by utilising EPR to identify intrinsic/dopant oxidation state changes during photoirradiation. The development of copper-based sensitizers (by Prof Pope) will be explored to maximise photoexcitation profiles and optimise charge-transfer processes providing a sustainable, low-cost route towards solar cells of the future.
Project aims and methods
This project will develop transferable skills, including experimental techniques and computational analysis.
•The primary experimental technique employed will be advanced Electron Paramagnetic Resonance (EPR) spectroscopy and related hyperfine techniques, utilising seven different state-of-the-art spectrometers housed within the research group (estimated value £2.4M). Full operational training of these specialised facilities will be provided, to enable autonomous and independent use.
•Responsibility for development and implementation of a new facility in Time-Resolved EPR spectroscopy, adding new capacity to existing infrastructure and developing a unique research profile within CU.
•Specialised training in liquid cryogens for low temperature measurements and laser safety will be integral to the project.
•Data analysis and interpretation of experimental datasets will be performed using simulation software, supplemented by computational DFT calculations, and visualised using advanced packages (e.g. Matlab toolboxes, ORCA, VESTA).
•Presentation skills will be developed through monthly group seminars, and contributions at (inter)national conferences.
Start date: 1st October 2019
Dr Emma Richards - https://www.cardiff.ac.uk/people/view/38469-richards-emma
Professor Simon Pope - https://www.cardiff.ac.uk/people/view/38559-pope-simon
Professor Damien Murphy - https://www.cardiff.ac.uk/people/view/38540-murphy-damien