  Knowledge of the charge-carrier recombination lifetime, tau, is crucial for
the various applications of photovoltaic perovskites. We studied the novel
inorganic perovskite, CsPbBr3 and we observe recombination dynamics beyond 1 ms
below 200 K and tau approaching 100 us at room temperature. Time-resolved
microwave-detected photoconductivity decay (TRMCD), used in combination with
injection dependence, evidence that tau is dominated by impurity charge
trapping. The observed injection dependence is well corroborated by modeling of
the trap mechanism. The ultra-long decay time is also consistent with
photoconductivity measurements with a continuous-wave excitation at powers
corresponding to around one Sun irradiation. While in principle charge-carrier
trapping may limit the photovoltaic efficiency in single-cell photovoltaic
devices, it could also lead to enhanced efficiency in tandem cells as well as
for alternative applications including photodetection and quantum information
storage.
