Machine-Learning-Assisted Investigation on Benign Ion Migration in Metal Halide Perovskites

The Journal of Physical Chemistry Letters, Journal Year: 2025, Volume and Issue: unknown, P. 2614 - 2620

Published: March 4, 2025

Defect-assisted ion migration is one of the important issues that results in instability and non-radiative losses hybrid organic-inorganic metal halide perovskite solar cells. In this work, based on deep potential (DP) model, a long-time-scale molecular dynamics (MD) simulation has been employed to capture interstitial-assisted iodine process. The indicate that, when interstitial (Ii) begins migrate, serious structural distortion becomes mild, weakening electron-vibration interaction. trap state induced by trimer undergoes "deep-shallow-deep" dynamic process, which ultimately leads an improvement carrier lifetime during Our work confirms different processes are strongly correlated perovskites demonstrates migration, considered be detrimental, can become benign particular case. reported provide new fundamental insight improve efficiency CH3NH3PbI3

Language: Английский

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Atomistic Origin of Microsecond Carrier Lifetimes at Perovskite Grain Boundaries: Machine Learning-Assisted Nonadiabatic Molecular Dynamics

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 29, 2025

The polycrystalline nature of perovskites, stemming from their facile solution-based fabrication, leads to a high density grain boundaries (GBs) and point defects. However, the impact GBs on perovskite performance remains uncertain, with contradictory statements found in literature. We developed machine learning force field, sampled GB structures nanosecond time scale, performed nonadiabatic (NA) molecular dynamics simulations charge carrier trapping recombination stoichiometric doped GBs. reveal long, microsecond lifetimes, approaching experimental data, separation at small NA coupling, 0.01-0.1 meV. Stoichiometric exhibit transient trap states, which, however, are not particularly detrimental lifetime. Halide dopants form interstitial defects bulk, but have stabilizing influence structure by passivating undersaturated Pb atoms reducing state formation. On contrary, excess destabilizes GBs, allowing formation persistent midgap states that charges. Still, lifetime reduces relatively little, because decouple bands, charges more likely escape back into bands upon structural fluctuation. atomistic study its provides valuable insights complex properties perovskites intricate role material performance.

Language: Английский

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Impact of Hydrogen Vacancies on Non‐Radiative Recombination in Metal‐Halide Perovskites

Angewandte Chemie International Edition, Journal Year: 2025, Volume and Issue: unknown

Published: March 11, 2025

Hydrogen vacancies (VH) were considered major non-radiative recombination centers in hybrid perovskites. By employing a multiscale approach that combines first-principles calculations and molecular dynamics (MDs) simulations, our findings indicated the VH impact was overestimated due to previous metastable configurations. The organic molecules with located on either nitrogen or carbon atom act as ligands form energetically stable dimers Pb2+ cations. These lower energy by 0.35-0.97 eV MAPbI3 0.88-1.01 FAPbI3, compared non-bonding significantly boosted potential barriers of hole capture, resulting dramatic reduction carrier capture coefficients over 10 orders magnitude. Consequently, total (Ctotal) for dominant FAPbI3 are order 10-17 10-31 cm-3s-1, respectively. uncovering negligible recombination, this work shifts focus toward more significant defects, instance, iodine interstitial (with coefficient 10-8 cm-3s-1), thereby paving way optimizing perovskite solar cells efficiency meet Shockley-Queisser limit.

Language: Английский

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Generalization of Quantum-Trajectory Surface Hopping to Multiple Quantum States

Journal of Chemical Theory and Computation, Journal Year: 2025, Volume and Issue: unknown

Published: March 10, 2025

In this work, we present a generalization of the quantum trajectory surface hopping (QTSH) to multiple states and its implementation in Libra package for nonadiabatic dynamics. lieu ad hoc velocity rescaling used many trajectory-based approaches, QTSH utilizes forces evolve nuclear degrees freedom continuously. It also lifts unphysical constraint enforcing total energy conservation at individual level rather conserves ensemble level. Leveraging our new multistate QTSH, perform comparative analysis method with conventional fewest switches approach. We combine decoherence corrections based on simplified decay mixing (SDM) exact factorization (XF), leading QTSH-SDM QTSH-XF schemes. Using Holstein, superexchange, phenol model Hamiltonians, assess relative accuracy resulting combined schemes reproducing branching ratios, population, coherence dynamics broad range initial conditions. observe that correction is crucial improve as well internal consistency between population from probability active state.

Language: Английский

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Impact of Hydrogen Vacancies on Non‐Radiative Recombination in Metal‐Halide Perovskites

Angewandte Chemie, Journal Year: 2025, Volume and Issue: unknown

Published: March 11, 2025

Abstract Hydrogen vacancies (V H ) were considered major non‐radiative recombination centers in hybrid perovskites. By employing a multiscale approach that combines first‐principles calculations and molecular dynamics (MDs) simulations, our findings indicated the V impact was overestimated due to previous metastable configurations. The organic molecules with located on either nitrogen or carbon atom act as ligands form energetically stable dimers Pb 2+ cations. These lower energy by 0.35–0.97 eV MAPbI 3 0.88–1.01 FAPbI , compared non‐bonding significantly boosted potential barriers of hole capture, resulting dramatic reduction carrier capture coefficients over 10 orders magnitude. Consequently, total ( C for dominant are order −17 −31 cm −3 s −1 respectively. uncovering negligible recombination, this work shifts focus toward more significant defects, instance, iodine interstitial (with coefficient −8 ), thereby paving way optimizing perovskite solar cells efficiency meet Shockley–Queisser limit.

Language: Английский

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Nuclear Quantum Effects Enhance Structural Stability but Accelerate Charge Carrier Recombination in MHyPbBr₃ Perovskite

The Journal of Physical Chemistry Letters, Journal Year: 2024, Volume and Issue: unknown, P. 12076 - 12082

Published: Nov. 26, 2024

Hybrid organic–inorganic perovskites exhibit significant nuclear quantum effects (NQEs) due to their light hydrogen atoms. By performing ring polymer molecular dynamics, ab initio and nonadiabatic dynamics simulations on the MHyPbBr3 (MHy+ = CH3NH2NH2+) perovskites, we demonstrate that NQEs stabilize lattice by suppressing atomic motions accelerate nonradiative charge recombination. This stabilization arises from synergistic of Pb–N coordination bonds N–H···Br bonds, which enhance interactions. As a result, Pb–Br octahedra, particularly [Pb(1)Br6]4– octahedra supporting electron hole, are well-preserved, promoting electronic wavefunction delocalization increasing electron–hole overlap. These coupling overcoming reduced motions. Overall, this prolonged decoherence time recombination NQEs. Our study highlights unique influence geometrical stability carrier in MHyPbBr3, offering fundamental insights for future material design.

Language: Английский

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Schottky Defects Suppress Nonradiative Recombination in CH₃NH₃PbI₃ through Charge Localization

The Journal of Physical Chemistry Letters, Journal Year: 2024, Volume and Issue: unknown, P. 215 - 221

Published: Dec. 23, 2024

Hybrid lead halide perovskites are promising materials for photovoltaic applications due to their exceptional optoelectronic properties. Here, we investigate the impact of Schottky defects─specifically PbI2(VPbI2) and CH3NH3I (VMAI) vacancies─on nonradiative recombination in CH3NH3PbI3 using time-dependent density functional theory nonadiabatic (NA) molecular dynamics. Our results reveal that defects do not alter fundamental bandgap or introduce trap states but instead distort surrounding lattice, localizing hole distribution. This reduces spatial overlap electron wave functions, weakening NA coupling increasing intensitieis high-intensity phonon modes accelerate dephasing. Consequently, lifetimes extend 2.1 2.6 ns VPbI2 VMAI, respectively─over double pristine CH3NH3PbI3. work demonstrates potential enhance perovskite solar cell performance by suppressing recombination.

Language: Английский

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