TY - JOUR
T1 - A Conical Intersection Perspective on the Low Nonradiative Recombination Rate in Lead Halide Perovskites
AU - Esch, Michael P.
AU - Shu, Yinan
AU - Levine, Benjamin G.
N1 - Publisher Copyright:
© 2019 American Chemical Society.
PY - 2019/4/4
Y1 - 2019/4/4
N2 - The utility of optoelectronic materials can be greatly reduced by the presence of efficient pathways for nonradiative recombination (NRR). Lead halide perovskites have garnered much attention in recent years as materials for solar energy conversion, because they readily absorb visible light, are easy to synthesize, and have a low propensity for NRR. Here we report a theoretical study of the pathways for NRR in an archetypal lead halide perovskite: CsPbBr 3 . Specifically, we identified a set of conical intersection (CIs) in both a molecule-sized cluster model (Cs 4 PbBr 6 ) and nanoparticle model (Cs 12 Pb 4 Br 20 ) of the CsPbBr 3 surface. The energies of the minimal energy CIs, corrected for both dynamical electron correlation and spin-orbit coupling, are well above the bulk band gap of CsPbBr 3 , suggesting that these intersections do not provide efficient pathways for NRR in this material. Analysis of the electronic structure at these intersections suggests that the ionic nature of the bonds in CsPbBr 3 may play a role in the high energy of these CIs. The lowest-energy intersections all involve charge transfer over long distances, whether it be across a dissociated bond or between neighboring unit cells.
AB - The utility of optoelectronic materials can be greatly reduced by the presence of efficient pathways for nonradiative recombination (NRR). Lead halide perovskites have garnered much attention in recent years as materials for solar energy conversion, because they readily absorb visible light, are easy to synthesize, and have a low propensity for NRR. Here we report a theoretical study of the pathways for NRR in an archetypal lead halide perovskite: CsPbBr 3 . Specifically, we identified a set of conical intersection (CIs) in both a molecule-sized cluster model (Cs 4 PbBr 6 ) and nanoparticle model (Cs 12 Pb 4 Br 20 ) of the CsPbBr 3 surface. The energies of the minimal energy CIs, corrected for both dynamical electron correlation and spin-orbit coupling, are well above the bulk band gap of CsPbBr 3 , suggesting that these intersections do not provide efficient pathways for NRR in this material. Analysis of the electronic structure at these intersections suggests that the ionic nature of the bonds in CsPbBr 3 may play a role in the high energy of these CIs. The lowest-energy intersections all involve charge transfer over long distances, whether it be across a dissociated bond or between neighboring unit cells.
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U2 - 10.1021/acs.jpca.9b00952
DO - 10.1021/acs.jpca.9b00952
M3 - Article
C2 - 30843698
AN - SCOPUS:85063961493
SN - 1089-5639
VL - 123
SP - 2661
EP - 2673
JO - Journal of Physical Chemistry A
JF - Journal of Physical Chemistry A
IS - 13
ER -