Interfacial charge dynamics
Ultrafast reflection spectroscopy resolves carrier mobility and surface recombination velocity at the buried interfaces of solar cells — the numbers that decide open-circuit voltage.
We use time-resolved and interface-selective ultrafast spectroscopy to follow charge carriers, spins and chemical bonds as they evolve — and use what we learn to build better solar cells, photocatalysts and spin-based devices.
We turn the picoseconds that decide device efficiency — the interfacial field, the spin state, the reaction intermediate — into measurable, predictable design rules.
How fast does charge move at an interface? How long does a spin remember its direction? And what actually happens in the first picoseconds of a catalytic reaction?
Ultrafast reflection spectroscopy resolves carrier mobility and surface recombination velocity at the buried interfaces of solar cells — the numbers that decide open-circuit voltage.
Chiral perovskites convert light into spin-polarized currents. We quantify how spin-orbit coupling, deformation potential and lattice strain set the spin lifetime.
In-situ ultrafast spectroscopy follows holes and electrons through water oxidation and H2O2 photosynthesis, telling us which intermediate is worth engineering.
Associate Professor · Department of Mechanical and Energy Engineering
Xihan Chen received his B.Sc. in Chemistry from HKUST (2012) and his Ph.D. in Chemistry from UC Berkeley (2017), working on ultrafast spectroscopy of photocatalytic water oxidation with Tanja Cuk. From 2017 to 2021 he was a postdoctoral researcher at the National Renewable Energy Laboratory (NREL) with Matthew Beard, studying hot carrier and spin dynamics in halide perovskites. He joined SUSTech in 2021.
His group develops interface-selective time-resolved spectroscopy — transient reflection, transient absorption and polarization-resolved pump–probe — to connect the femtosecond behaviour of carriers and spins to the macroscopic efficiency and stability of energy conversion devices.
Ten papers we are proud of. The complete record, with author roles and DOIs, is on the publications page.
Ph.D. and Master's students, postdocs and undergraduates interested in ultrafast spectroscopy, perovskites and solar fuels are welcome to get in touch.