Fig. 1: Principle of perovskite ultrafast infrared nano-imaging.
From: Nanoscale heterogeneity of ultrafast many-body carrier dynamics in triple cation perovskites
a Unit cell structure of the triple cation perovskite \([{({{{{{{{{\rm{FA}}}}}}}}}_{0.83}{{{{{{{{\rm{MA}}}}}}}}}_{0.17})}_{0.95}{{{{{{{{\rm{Cs}}}}}}}}}_{0.05}]{{{{{{{\rm{Pb}}}}}}}}{({{{{{{{{\rm{I}}}}}}}}}_{0.83}{{{{{{{{\rm{Br}}}}}}}}}_{0.17})}_{3}\). b Photoinduced polaron formation in perovskites. An injected photoinduced carrier is self-trapped by the deformation of the surrounding lattice. c Ultrafast infrared nano-imaging of triple cation perovskite with 515 nm visible pump excitation with fluence of ~80 μJ/cm2, and 8.3 μm mid-infrared probe, detecting the amplitude of the transient nano-localized carrier absorption AHPP(T), which we attributed to either nano-localized polaron absorption or Drude carrier response.
