Nanoscale size effects in α-FAPbI3 evinced by large-scale ab initio simulations

Abstract Formamidinium-lead-iodide (FAPbI3) has a rich phase diagram, and long-range correlation between the organic cations and lattice dipoles can influence phase transitions and optoelectronic properties. System size effects are crucial for an appropriate theoretical description of FAPbI3. We per...

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Main Authors: Virginia Carnevali, Lorenzo Agosta, Vladislav Slama, Nikolaos Lempesis, Andrea Vezzosi, Ursula Rothlisberger
Format: Article
Language:English
Published: Nature Portfolio 2025-07-01
Series:Nature Communications
Online Access:https://doi.org/10.1038/s41467-025-61351-7
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author Virginia Carnevali
Lorenzo Agosta
Vladislav Slama
Nikolaos Lempesis
Andrea Vezzosi
Ursula Rothlisberger
author_facet Virginia Carnevali
Lorenzo Agosta
Vladislav Slama
Nikolaos Lempesis
Andrea Vezzosi
Ursula Rothlisberger
author_sort Virginia Carnevali
collection DOAJ
description Abstract Formamidinium-lead-iodide (FAPbI3) has a rich phase diagram, and long-range correlation between the organic cations and lattice dipoles can influence phase transitions and optoelectronic properties. System size effects are crucial for an appropriate theoretical description of FAPbI3. We perform a systematic ab initio study on the structural and electronic properties of the photoactive phase of FAPbI3 as a function of system size. To ensure an accurate theoretical description, three criteria must be satisfied: the (correct) value of the band gap, the extent (or the absence of) structural distortions, and the zeroing out of the total dipole moment. The net dipole moment vanishes as the system size increases due to PbI6 octahedra distortions rather than due to FA+ rotations. Additionally, thermal band gap fluctuations are predominantly correlated with octahedral tilting. The optimal agreement between simulation results and experimental properties for FAPbI3 is only achieved by system sizes approaching the nanoscale.
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publishDate 2025-07-01
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spelling doaj-art-1e4862d626b34ecf93034e8a99d2bef92025-08-20T03:42:55ZengNature PortfolioNature Communications2041-17232025-07-011611810.1038/s41467-025-61351-7Nanoscale size effects in α-FAPbI3 evinced by large-scale ab initio simulationsVirginia Carnevali0Lorenzo Agosta1Vladislav Slama2Nikolaos Lempesis3Andrea Vezzosi4Ursula Rothlisberger5Laboratory of Computational Chemistry and Biochemistry, Institute of Chemical Sciences and Engineering, Swiss Federal Institute of Technology (EPFL)Laboratory of Computational Chemistry and Biochemistry, Institute of Chemical Sciences and Engineering, Swiss Federal Institute of Technology (EPFL)Laboratory of Computational Chemistry and Biochemistry, Institute of Chemical Sciences and Engineering, Swiss Federal Institute of Technology (EPFL)Laboratory of Computational Chemistry and Biochemistry, Institute of Chemical Sciences and Engineering, Swiss Federal Institute of Technology (EPFL)Laboratory of Computational Chemistry and Biochemistry, Institute of Chemical Sciences and Engineering, Swiss Federal Institute of Technology (EPFL)Laboratory of Computational Chemistry and Biochemistry, Institute of Chemical Sciences and Engineering, Swiss Federal Institute of Technology (EPFL)Abstract Formamidinium-lead-iodide (FAPbI3) has a rich phase diagram, and long-range correlation between the organic cations and lattice dipoles can influence phase transitions and optoelectronic properties. System size effects are crucial for an appropriate theoretical description of FAPbI3. We perform a systematic ab initio study on the structural and electronic properties of the photoactive phase of FAPbI3 as a function of system size. To ensure an accurate theoretical description, three criteria must be satisfied: the (correct) value of the band gap, the extent (or the absence of) structural distortions, and the zeroing out of the total dipole moment. The net dipole moment vanishes as the system size increases due to PbI6 octahedra distortions rather than due to FA+ rotations. Additionally, thermal band gap fluctuations are predominantly correlated with octahedral tilting. The optimal agreement between simulation results and experimental properties for FAPbI3 is only achieved by system sizes approaching the nanoscale.https://doi.org/10.1038/s41467-025-61351-7
spellingShingle Virginia Carnevali
Lorenzo Agosta
Vladislav Slama
Nikolaos Lempesis
Andrea Vezzosi
Ursula Rothlisberger
Nanoscale size effects in α-FAPbI3 evinced by large-scale ab initio simulations
Nature Communications
title Nanoscale size effects in α-FAPbI3 evinced by large-scale ab initio simulations
title_full Nanoscale size effects in α-FAPbI3 evinced by large-scale ab initio simulations
title_fullStr Nanoscale size effects in α-FAPbI3 evinced by large-scale ab initio simulations
title_full_unstemmed Nanoscale size effects in α-FAPbI3 evinced by large-scale ab initio simulations
title_short Nanoscale size effects in α-FAPbI3 evinced by large-scale ab initio simulations
title_sort nanoscale size effects in α fapbi3 evinced by large scale ab initio simulations
url https://doi.org/10.1038/s41467-025-61351-7
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AT vladislavslama nanoscalesizeeffectsinafapbi3evincedbylargescaleabinitiosimulations
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