Ultrafast transient photocurrent in hybrid lead halide perovskites

Organic-inorganic hybrid halide perovskites, including methylammonium lead iodide and bromide, have demonstrated promising applications in photovoltaics. We performed ultrafast transient photocurrent (TPC) measurements in single-crystalline perovskite microribbons at cryogenic temperatures, to investigate their charge dynamics and transport at ultrafast timescales. Our measurements reveal that the probe-induced photocurrent is substantially suppressed by a pump pulse. The recovery time of this suppression is significantly shortened by the applied electric field, which we attribute to the drift of the photogenerated carriers out of the laser-illuminated region. Interestingly, when the photoexcitation energy is slightly below the bandgap, we observe a much stronger photocurrent suppression, accompanied by a sharp peak at zero delay with a temporal width approximately 10 ps. I will discuss possible mechanisms and its implications on exciton dynamics and transport.