Screening in crystalline liquids protects energetic carriers in hybrid perovskites

Hybrid lead halide perovskites exhibit carrier properties that resemble those of pristine nonpolar semiconductors despite static and dynamic disorder, but how carriers are protected from efficient scattering with charged defects and optical phonons is unknown. Here, we reveal the carrier protection mechanism by comparing three single-crystal lead bromide perovskites: CH 3 NH 3 PbBr 3 , CH(NH 2 ) 2 PbBr 3 , and CsPbBr 3 . We observed hot fluorescence emission from energetic carriers with ~10 2 -picosecond lifetimes in CH 3 NH 3 PbBr 3 or CH(NH 2 ) 2 PbBr 3 , but not in CsPbBr 3 . The hot fluorescence is correlated with liquid-like molecular reorientational motions, suggesting that dynamic screening protects…

• NS
  National Science Foundation

  Award: DMR 1420634