%0 Journal Article %1 doi:10.1021/acs.jpclett.7b03286 %A Umari, Paolo %A Mosconi, Edoardo %A De Angelis, Filippo %D 2018 %J The Journal of Physical Chemistry Letters %K bindingenergy exciton perovskite %N 0 %P 620-627 %R 10.1021/acs.jpclett.7b03286 %T Infrared Dielectric Screening Determines the Low Exciton Binding Energy of Metal-Halide Perovskites %U http://dx.doi.org/10.1021/acs.jpclett.7b03286 %V 0 %X The performance of lead-halide perovskites in optoelectronic devices is due to a unique combination of factors, including highly efficient generation, transport, and collection of photogenerated charge carriers. The mechanism behind efficient charge generation in lead-halide perovskites is still largely unknown. Here, we investigate the factors that influence the exciton binding energy (Eb) in a series of metal-halide perovskites using accurate first-principles calculations based on solution of the Bethe-Salpeter equation, coupled to ab initio molecular dynamics simulations. We find that Eb is strongly modulated by screening from low-energy phonons, which account for a factor ∼2 Eb reduction, while dynamic disorder and rotational motion of the organic cations play a minor role. We calculate Eb = 15 meV for MAPbI3, in excellent agreement with recent experimental estimates. We then explore how different material combinations (e.g., replacing Pb → Pb:Sn→ Sn; and MA → FA → Cs) may lead to different Eb values and highlight the mechanisms underlying Eb tuning.

@article{doi:10.1021/acs.jpclett.7b03286, abstract = { The performance of lead-halide perovskites in optoelectronic devices is due to a unique combination of factors, including highly efficient generation, transport, and collection of photogenerated charge carriers. The mechanism behind efficient charge generation in lead-halide perovskites is still largely unknown. Here, we investigate the factors that influence the exciton binding energy (Eb) in a series of metal-halide perovskites using accurate first-principles calculations based on solution of the Bethe-Salpeter equation, coupled to ab initio molecular dynamics simulations. We find that Eb is strongly modulated by screening from low-energy phonons, which account for a factor ∼2 Eb reduction, while dynamic disorder and rotational motion of the organic cations play a minor role. We calculate Eb = 15 meV for MAPbI3, in excellent agreement with recent experimental estimates. We then explore how different material combinations (e.g., replacing Pb → Pb:Sn→ Sn; and MA → FA → Cs) may lead to different Eb values and highlight the mechanisms underlying Eb tuning. }, added-at = {2018-01-24T09:42:35.000+0100}, author = {Umari, Paolo and Mosconi, Edoardo and De Angelis, Filippo}, biburl = {https://www.bibsonomy.org/bibtex/29da5840ee86156c8e8af9e83bfa6c8d5/cgoehler}, description = {Infrared Dielectric Screening Determines the Low Exciton Binding Energy of Metal-Halide Perovskites - acs.jpclett.7b03286}, doi = {10.1021/acs.jpclett.7b03286}, eprint = {http://dx.doi.org/10.1021/acs.jpclett.7b03286}, interhash = {3cbad418c448bd25596ee719afdba39e}, intrahash = {9da5840ee86156c8e8af9e83bfa6c8d5}, journal = {The Journal of Physical Chemistry Letters}, keywords = {bindingenergy exciton perovskite}, note = {PMID: 29336156}, number = 0, pages = {620-627}, timestamp = {2018-01-24T09:42:35.000+0100}, title = {Infrared Dielectric Screening Determines the Low Exciton Binding Energy of Metal-Halide Perovskites}, url = {http://dx.doi.org/10.1021/acs.jpclett.7b03286}, volume = 0, year = 2018 }