We are dedicated to utilizing advanced ultrafast optical spectroscopies to investigate novel photophysics in emerging optical materials and optoelectronic devices.
I) Fundamental study: develop and apply femtosecond laser spectroscopies to study the nonlinear optical properties, charge carrier/spin/energy transfer dynamics/mechanisms, and novel photophysics in light-harvesting, light-emitting materials and related devices (eg., solar cell, photodetector, laser, etc). These techniques will afford a prerogative opportunity to systematically explore the individual photophysical processes with high spatial, spectral, and temporal resolution. The materials include novel low-dimensional semiconductors (eg., quantum dots, nanocrystals, 2D perovskites, 2D TMDs). The energy relaxation, realspace transport, and radiative/non-radiative recombination dynamics of photo-excited carriers are able to be understood by manipulating, controlling, and detecting charge carriers in the functional optoelectronic systems with femtosecond time resolution.
II) Applications: based on the obtained novel photophysical properties in optoelectronic materials/devices, we aim to eventually translate the ground-breaking research findings from the laboratory to prototypes and eventually apply the technical know-how to products and solutions for novel optoelectronic technologies.
Ultrafast optical spectroscopy techniques in our lab:
Transient-absorption spectroscopy (TA) more commonly known as optical pump-probe spectroscopy allows us to probe the charge carrier populations involved in both radiative and non-radiative transitions that occurred in femtosecond timescale. TA is a powerful technique to provide important parameters (eg., device interfacial charge carrier/energy transfer rate, carrier diffusion length, etc.) in many materials/nanostructures (organic/inorganic, semiconductor, liquid or solid samples) and various optoelectronics (solar cell, LED, laser, photodetectors, photocatalyst). Time resolution: ~50 fs, probe wavelength: UV-IR.
Optical pump/Terahertz Probe (OPTP): using meV THz waves to probe the mobile charge carrier/mobility/photoconductivity /phonon dynamics in materials and devices.
Time-resolved photoluminescence (TRPL) using a streak camera combined with a spectrometer allows us to collect the transient PL spectra and lifetime in the picosecond regime (time resolution 5 ps).
Microscope TA/PL/TRPL: TA, PL/TRPL are also combined with microscopes to obtain the spatially resolved optical properties/charge carrier dynamics with resolution: <1 µm.
Material and applications:
