Hot-carrier cooling and photoinduced refractive index changes in organic–inorganic lead halide perovskites

Metal-halide perovskites are at the frontier of optoelectronic research due to solution processability and excellent semiconductor properties. Here we use transient absorption spectroscopy to study hot-carrier distributions in CH3NH3PbI3 and quantify key semiconductor parameters. Above bandgap, non-resonant excitation creates quasi-thermalized carrier distributions within 100 fs. During carrier cooling, a sub-bandgap transient absorption signal arises at ∼ 1.6 eV, which is explained by the interplay of bandgap renormalization and hot-carrier distributions. At higher excitation densities, a 'phonon bottleneck' substantially slows carrier cooling. This effect indicates a low contribution from inelastic…

• DF
  Deutsche Forschungsgemeinschaft
• CC
  Cambridge Commonwealth Trust
• EA
  Engineering and Physical Sciences Research Council

  Awards: EP/M005143/1, EP/G060738/1
• MF
  Marsden Fund