Ultrafast terahertz snapshots of excitonic Rydberg states and electronic coherence in an organometal halide perovskite

The generation of bound electron and hole pairs—excitons—is a key process in photovoltaic technologies, yet it is challenging to follow their initial dynamics. Here, Luoet al. probe the Rydberg eigenstates that characterize the excitonic transport and coherent conversion in a perovskite material.