Mar 2023
George studied MSci in chemistry at the University of Glasgow and graduated in 2019. He joined KAUST in early 2021 and is doing his Ph.D. in Professor Omar Mohammed’s group in the AMPM centre. He worked on a number of different topics using a combination of ultrafast spectroscopy and DFT, with a particular focus on the photophysics of organic linkers in Metal Organic Frameworks.
Understanding how structural modifications influences the photophysics of organic linkers are vital for their incorporation into Metal Organic Frameworks (MoFs). In this study, the amine functional group on a terephthalic acid derivative was varied between the meta and ortho positions and investigated using a combination of steady state, ultrafast laser spectroscopy and time-dependent density functional theory (TD-DFT) calculations. Time-correlated single photon counting (TCSPC) reveals an increase in lifetime of the excited state when intramolecular twisting is restricted and the involvement of steric hindrance as the primary cause is confirmed with TD-DFT. Furthermore, intersystem crossing to accessible triplet states were uncovered using ns-transient absorption spectroscopy. This study highlights the importance of how judicious structural modifications of organic linkers may be used to improve the performance of MOFs for photocatalytic, light sensing and emitting applications.