  Hybrid metal-organic perovskite solar cells have astounded the solar cell
community with their rapid rise in efficiency over the past three years.
Despite this success, the basic processes governing the photogeneration of free
charges, particularly their dynamics and efficiency, remain unknown. Here we
use ultrabroadband pulses of THz frequency light to see the intrinsic
photophysical properties of single crystal lead halide perovskite just
femtoseconds after a photon is first absorbed. Our spectra reveal the dynamics
and efficiencies of free charge creation, the remarkable ease in which they
move through the lattice and the complicated interplay between free and bound
charges in these materials.
