Optimizing Sublattice Correlation to Enhance Stability and Charge Carrier Lifetime in Mixed Halide Perovskites

Nano Letters, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 2, 2025

A-site cations in ABX3 metal halide perovskites do not contribute to the frontier electronic states. They influence optoelectronic properties indirectly through interaction with BX3 sublattice. By systematically investigating correlated motions of Cs and PbX3 lattice (X = Cl, Br, I), we demonstrate that between two subsystems depends on electronegativity size X-site anion. The most electronegative Cl minimizes thermal atomic fluctuations, favoring performance. CsPbI3 is improved by Cl-doping. Nonadiabatic molecular dynamics simulations charge carrier lifetime extended nearly an order magnitude when fluctuations are minimized, due reduced electron–vibrational interactions, agreement experiments. detailed atomistic examination significant impact motion sublattices its perovskite stability exciton offers theoretical guidelines for optimizing devices.

Language: Английский

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Sub-bandgap charge harvesting and energy up-conversion in metal halide perovskites: ab initio quantum dynamics

npj Computational Materials, Journal Year: 2025, Volume and Issue: 11(1)

Published: Jan. 11, 2025

Metal halide perovskites (MHPs) exhibit unusual properties and complex dynamics. By combining ab initio time-dependent density functional theory, nonadiabatic molecular dynamics machine learning, we advance quantum simulation to nanosecond timescale demonstrate that large fluctuations of MHP defect energy levels extend light absorption longer wavelengths enable trapped charges escape into bands. This allows low photons contribute photocurrent through up-conversion. Deep can become shallow transiently vice versa, altering the traditional classification deep. While fluctuate more in MHPs than semiconductors, some levels, e.g., Pb interstitials, remain far from band edges, acting as charge recombination centers. Still, many defects deemed detrimental based on static structures, are fact benign The extended harvesting up-conversion provide strategies for design novel solar, optoelectronic, information devices.

Language: Английский

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Compression of Organic Molecules Coupled with Hydrogen Bonding Extends the Charge Carrier Lifetime in BA₂SnI₄

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(23), P. 16314 - 16323

Published: May 30, 2024

Two-dimensional (2D) metal halide perovskites, such as BA2SnI4 (BA═CH3(CH2)3NH3), exhibit an enhanced charge carrier lifetime in experiments under strain. Experiments suggest that significant compression of the BA molecule, rather than inorganic lattice, contributes to this enhancement. To elucidate underlying physical mechanism, we apply a moderate compressive strain entire system and subsequently introduce molecules. We then perform ab initio nonadiabatic molecular dynamics simulations nonradiative electron–hole recombination. observe overall lattice reduces atomic motions decreases coupling, thereby delaying Additionally, molecules enhances hydrogen bonding between iodine atoms, which lengthens Sn–I bonds, distorts [SnI6]4– octahedra, suppresses further, thus reducing coupling. Also, elongated bonds weakened antibonding interactions increase band gap. Altogether, delays recombination by more factor 3. Our provide new valuable insights into how strain, accommodated primarily organic ligands, positively influences optoelectronic properties 2D layered offering promising pathway for further performance improvements.

Language: Английский

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Suppressing Polaronic Defect–Photocarrier Interaction in Halide Perovskites by Pre-distorting Its Lattice

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

Published: Jan. 8, 2025

In halide perovskites, photocarriers can have strong polaronic interactions with point defects. For iodide-deficient MAPbI3, we found that the Fermi level shift significantly by 0.6–0.7 eV upon light illumination. This energy is accompanied formation of deep electron traps. These experimental observations are consistent a Pb–Pb dimer when photoexcited electrons trapped at an iodide vacancy. Interestingly, this interaction suppressed portion MA+ cations replaced smaller Cs+ ions. Density functional theory calculations reveal Cs-doping reduce distance between two Pb atoms across vacancy, even without trapping. The predistortion lattice induced cation replacement resembles formed trapping defect site, which explains suppression light-induced effects observed in experiment. Our finding unveils counterintuitive strategy to enhance photostability perovskites preintroducing distortions into its lattice.

Language: Английский

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Fabricating Perovskite Films for Solar Modules from Small to Large Scale

Advanced Functional Materials, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 17, 2025

Abstract Perovskite solar cells (PSCs) have gained significant attention for their high efficiency, low cost, and versatile application possibilities, which are expected to play a critical role in shaping the future of photovoltaics (PV) markets. However, power conversion efficiency (PCE) stability large‐area PSCs still cannot meet industrialization requirements, mainly associated with unsatisfactory quality perovskite films. This review first identifies factors contributing film difference between small‐area films, such as solvent evaporation process, reaction crystallization kinetics, etc. results undesired perovskites, e.g. inhomogeneity terms morphology, composition, phase, crystal size, orientation. Solvent systems customed different scalable preparation process based on volatility, solubility, coordination ability perovskite. Furthermore, various additives incorporated further regulate surface tension change intermediate phase evolution. Finally, we transition from level device explore current advancements challenges related PCE commercialization process.

Language: Английский

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Self-passivation of Halide Interstitial Defects by Organic Cations in Hybrid Lead-Halide Perovskites: Ab Initio Quantum Dynamics

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(42), P. 29255 - 29265

Published: Oct. 11, 2024

Halide interstitial defects severely hinder the optoelectronic performance of metal halide perovskites, making research on their passivation crucial. We demonstrate, using ab initio nonadiabatic molecular dynamics simulations, that hydrogen vacancies (H

Language: Английский

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Ion Migration at Metal Halide Perovskite Grain Boundaries Elucidated with a Machine Learning Force Field

The Journal of Physical Chemistry Letters, Journal Year: 2024, Volume and Issue: unknown, P. 12362 - 12369

Published: Dec. 9, 2024

Metal halide perovskites are promising optoelectronic materials with excellent defect tolerance in carrier recombination, believed to arise largely from their unique soft lattices. However, weak lattice interactions also promote ion migration, leading serious stability issues. Grain boundaries (GBs) have been experimentally identified as the primary migration channels, but relevant mechanism remains elusive. Using molecular dynamics a machine learning force field, we directly model at common CsPbBr3 GB. We demonstrate that as-built GB model, containing 6400 atoms, experiences structural reconstruction over several nanoseconds, and only Br atoms diffuse after that. A fraction of near either migrate toward center or along through different channels. Increasing temperature not accelerates via Arrhenius activation allows more migrate. The energies much lower than bulk due large-scale distortions favorable non-stoichiometric local environments available GBs. Making composition stoichiometric by doping annealing can suppress migration. reported results provide valuable atomistic insights into properties metal perovskites.

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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Quantum Dynamics of Charge Carriers in Fullerenes Encapsulated by Covalent Organic Polyhedra: Choice of Fullerene Matters

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

Published: Feb. 28, 2025

Charge separation is at the heart of solar energy applications, and efficient materials require fast photoinduced electron transfer (ET) slow charge recombination (CR). Using time-dependent self-consistent density functional tight-binding theory combined with nonadiabatic (NA) molecular dynamics, we report a detailed analysis ET CR in hybrids composed photoactive covalent organic polyhedra (COP) encapsulated fullerenes. The occurs on subpicosecond time scale accelerates increasing fullerene diameter, C60 to C70 C84. As size increases, π-electron system available for interaction COP grows, fullerene-COP decreases, number states accept photoexcited accelerating ET. In comparison, nanosecond correlates length shortest axis because relevant state polarized that direction. largest least symmetrical C84 exhibits fastest slowest CR, making COP@C84 most promising hybrid. Both high-frequency bond stretching bending vibrations low-frequency breathing modes are involved processes, more present due its lower symmetry. 10–20 fs vibrationally induced coherence loss electronic subsystem contributes long lifetimes charge-separated states. comprehensive investigation structure–property relationship carrier dynamics COP@fullerene provides atomistic understanding interfacial processes generates guidelines rational design high-performance related applications.

Language: Английский

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Applications of machine learning in surfaces and interfaces

Chemical Physics Reviews, Journal Year: 2025, Volume and Issue: 6(1)

Published: March 1, 2025

Surfaces and interfaces play key roles in chemical material science. Understanding physical processes at complex surfaces is a challenging task. Machine learning provides powerful tool to help analyze accelerate simulations. This comprehensive review affords an overview of the applications machine study systems materials. We categorize into following broad categories: solid–solid interface, solid–liquid liquid–liquid surface solid, liquid, three-phase interfaces. High-throughput screening, combined first-principles calculations, force field accelerated molecular dynamics simulations are used rational design such as all-solid-state batteries, solar cells, heterogeneous catalysis. detailed information on for

Language: Английский

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