Dr. Xiaoyang Zhu

We are interested in photophysics in nano, molecular, and hybrid semiconductors and interfaces. We focus on fundamental interactions beyond the single particle approximation, and probe the dynamics of quasiparticles (excitons, polarons, polaritons, etc.) and their many-body interactions. These interactions are important to a range of optoelectronic processes, such as solar energy conversion, light emission, and polariton condensation. We employ state-of-the-art experimental techniques, including, among others, time-resolved photoemission spectroscopy, femtosecond nonlinear optical spectroscopies, transient absorption and time-resolved fluorescence spectroscopies and microscopies, 2D electronic spectroscopies, and scanning probe spectroscopies. As examples, recent discoveries in our lab revealed how dynamic screening and large polaron formation can make lead halide perovskite defect tolerant, how an exciton can split into two in organic semiconductors via the singlet fission process, and how an electron-hole pair can separate across a van der Waals interface between two 2D semiconductors.