1 research outputs found
Photoinduced Localized Hole Delays Nonradiative Electron–Hole Recombination in Cesium–Lead Halide Perovskites: A Time-Domain Ab Initio Analysis
All-inorganic perovskites have attracted intense interest as promising
photovoltaic materials due to their excellent performance. Using time
domain density functional theory combined with nonadiabatic (NA) molecular
dynamics, we demonstrate that a photoinduced localized polaron-like
hole greatly delays the nonradiative electron–hole recombination
relative to the structure with delocalized free charge of the CsPbBr<sub>3</sub>. This is because localized charge carriers diminish overlap
between electron and hole wave functions and decrease the NA coupling
by a factor of 6. In addition, polaron formation increases the band
gap of CsPbBr<sub>3</sub>, slowing down recombination further. The
smaller NA coupling and larger band gap compete successfully with
the longer decoherence time, extending the recombination to tens of
nanoseconds. The calculated recombination times show excellent agreement
with experiment. Our study reveals the atomistic mechanisms underlying
the suppression of recombination upon formation of localized polaron-like
holes and advances our understanding of the excited-state dynamics
of all-inorganic perovskite solar cells