1. Photoexcitation Dynamics in 2D Materials and Van der Waals Heterostructures

Graphene-like 2D materials have shown intriguing physical, chemical and mechanical properties. More importantly, they can be stacked arbitrarily to form Van der Waals heterostructures without lattice mismatching issue and bulk interference. In this project, we are generally interested at photoexcitation dynamics in 2D materials heterostructure at ultimate proximity, including the intralayer exciton formation and cooling, charge and energy transfer at interface, charge-transfer exciton and its separation to free carrier and more importantly, the role of energy, momentum, spin and electronic coupling on these process.

2. Interactions and Dynamics in Mixed Dimensional and Hybrid Heterostructures

The unique dimensionality and geometry of 2D materials offers an ideal platform to explore interactions and dynamics (e.g. charge and energy transfer process) at mixed dimensional or hybrid heterostructures, including 0D (quantum dot)-2D, 2D-3D (bulk material) heterostructures, metal nanoparticle-decorated 2D materials, organic molecules/semiconductors sensitized 2D materials.

3. Coupled Electron and Lattice Motion in Ionic and Molecular-like Inorganic Semiconductors and Heterostructures

Electrons in inorganic semiconductors have been generally treated as free electron with an effective mass. However, this picture could break down in semiconductors with moderate/strong long and short range electron-phonon coupling, e.g. ionic semiconductors (lead halide perovskites), molecular-like semiconductors with low dimensional (0D, 1D, 2D) crystal unit (Sb2S3, As2S3, MBABiI3). There, the motion of electron is coherently coupled to lattice vibration/deformation, leading to intriguing carrier localization and screening thus altered dynamics and energetics. Here we explore the coupled dynamics between carrier and lattice and how the composition/dimensionality affects long/short range interaction thus polaron properties. This becomes even more interesting and exciting when excitonic effect adds in in low dimensional materials or interfaical effect adds in in heterostructures.

4. Optical Properties and Photoexcitation Dynamics in Energy Conversion Materials and Devices

We are very open to interesting physical chemistry questions and collaborate with various research groups expertised on material growth and device fabrications and investigate the optical properties and photoexcitation dynamics related to solar energy conversion and light emission applications, e.g. organic solar cell, organic microlaser, quantum dot LED, perovskite opotoelectronic devices.