In the microscopy lab, we have pioneered in the development of time-resolved photoemission electron microscopy (TR-PEEM), by combining time resolution of ultrafast optical technique with spatial resolution provided by an electron microscope, we study carrier dynamics at the fundamental time and length scale in semiconductor and photovoltaic materials. This lab is centered around an aberration corrected spectroscopic photoelectron and low energy electron microscope (AC-SPELEEM), which allows imaging of electronic, chemical structure at surfaces and buried interfaces with nanometer spatial resolution. In the last few years, we have utilized our TR-PEEM technique to understand the charge trapping mechanism and the roles of defect in hybrid perovskite photovoltaic materials [1-4], in the studies of 2D material properties [5] and in the manipulation of photocarriers in semiconductors [6].
