Minh Huong Ha Thi
Maître de conférences/ Assoc. professor
Biography and Research interests
Minh-Huong Ha-Thi obtained her PhD from Ecole Normale Supérieure de Cachan in 2007, working on photophysical properties of fluorescent molecular systems for toxic metal detection with Dr. Isabelle Leray . In 2008, she joined the Institut des Sciences Moléculaire d’Orsay (ISMO) at Université Paris-Saclay after postdoctoral research with Dr. Thomas Gustavsson in CEA Saclay. Currently, her research focuses on the fundamental photophysical and photochemical processes for solar energy conversion.
One of the challenges in the field of photocatalysis is the development of catalysts that are efficient, selective, recyclable with the use of abundant elements, in particular for the production of hydrogen (HER) and the CO2 reduction reaction (CO2RR). Carrying out these reactions in an integrated system require the coupling of photoinduced electron transfer steps, light-induced charge accumulation and multi-electron catalysis. Indeed, the first photophysical events are of primordial importance and constitute the bottleneck for the optimization of the efficiency of CO2RR or HER. Understanding charge transfer processes as well as competitive relaxation reactions is therefore a key step to guide the optimization of these photosystems. Multi-timescale photophysical studies from femtosecond to continuous light are used to examine the relaxation mechanism after photoexcitation and during photocatalysis. We use several stationary and time-resolved spectroscopy techniques to access the multiscale dynamics of systems (transient absorption, fluorescence and time-resolved Raman). In particular, a pump-pump-probe nanosecond transient absorption setup using two excitation laser pulses was recently developed in our lab in order to probe charge photoaccumulation processes, the essential step to activate catalysts of multi-electronic reactions. Spectroscopic studies on thin film on transparent surface to allow the insertion of photosystems towards device are under development.
Our work currently focuses on the fundamental photophysical properties of different molecular photosystems such as metalloporphyrins, polyoxometalates (POM), hybrid systems with POMs inserted in organic hybrid porous networks (MOFs) or molecular donor-acceptor dyads.
Pump-pump-probe setup for probing charge accumulation.
Photoinduced processes in a BODIPY-C60 molecular dyad. (@J.Phys. Chem. B 2020, 124 (42), 9396-9410)
Time-resolved Raman for probing photoinduced electron transfer (@J. Phys. Chem. A 2020, 124 (14), 2736-2740)
Charge accumulation in a molecular dyad