Twist Angle-Dependent Intervalley Charge Carrier Transfer and Recombination in Bilayer WS₂

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(41), P. 22826 - 22835

Published: Oct. 5, 2023

A twist angle at a van der Waals junction provides handle to tune its optoelectronic properties for variety of applications, and comprehensive understanding how the modulates electronic structure, interlayer coupling, carrier dynamics is needed. We employ time-dependent density functional theory nonadiabatic molecular elucidate angle-dependent intervalley transfer recombination in bilayer WS2. Repulsion between S atoms twisted configurations weakens increases distance, softens layer breathing modes. Twisting has minor influence on K valleys while it lowers Γ raises Q because their wave functions are delocalized layers. Consequently, reduced energy gaps accelerate hole structures. Intervalley electron proceeds nearly an order magnitude faster than transfer. The more localized values larger bandgaps result smaller couplings recombination, making 3-4 times slower high-symmetry B2g breathing, E2g in-plane, A1g out-of-plane modes most active during recombination. extended lifetimes junctions favorable device performance.

Language: Английский

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Generation of holes from intra-valence band for enhanced oxidation potentials under visible light

Chem, Journal Year: 2024, Volume and Issue: 10(4), P. 1252 - 1267

Published: Feb. 19, 2024

Breaking the trade-off between oxidation potential and spectral response range has been an enduring challenge in field of photocatalysis. Here, we present a general approach to initiating intra-valence band (intra-VB) hole generation organic conjugated molecular crystals under visible light irradiation. The electron-deficient precursor with intrinsically empty side-VB is introduced by Fe3+, enabling electron transition from intra-VB side-VB. By studying five typical photocatalysts, demonstrate that holes strong potentials (up 3.85 V vs. RHE) are generated light. For PTCDA crystals, (HOCO-1 β) couple carbonyl groups, forming hole-coupled sites (–C=O+) extending lifetime 241 times 84.5 ns. Efficient transfer –C=O+ reactants subsequently initiates reactions. high-energy photogenerated exhibit scalable applicability, such as degradation pollutants water natural sunlight.

Language: Английский

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Photogenerated outer electric field induced electrophoresis of organic nanocrystals for effective solid-solid photocatalysis

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: Jan. 10, 2024

Abstract Rapid mass transfer in solid-solid reactions is crucial for catalysis. Although phoretic nanoparticles offer potential increased collision efficiency between solids, their implementation hindered by limited interaction ranges. Here, we present a self-driven long-range electrophoresis of organic nanocrystals facilitated rationally designed photogenerated outer electric field (OEF) on surface. Employing perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) molecular as model, demonstrate that directional OEF with an intensity 13.6-0.4 kV m −1 across range 25–200 μm. This OEF-driven targeted PTCDA onto the microplastic surface enhances activity subsequent decomposition microplastics (196.8 mg h ) into CO 2 As supported operando characterizations and theoretical calculations, surrounds initially, directing from electron-rich (0 1 1) to hole-rich $$(11\bar{2})$$ ( 11 2 ¯ ) Upon charge modulation, direction changes toward solid substrate. The electrophoretic effect anisotropic enrichment characteristics indicates advancements realizing effective photocatalysis.

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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i-PI 3.0: A flexible and efficient framework for advanced atomistic simulations

The Journal of Chemical Physics, Journal Year: 2024, Volume and Issue: 161(6)

Published: Aug. 14, 2024

Atomic-scale simulations have progressed tremendously over the past decade, largely thanks to availability of machine-learning interatomic potentials. These potentials combine accuracy electronic structure calculations with ability reach extensive length and time scales. The i-PI package facilitates integrating latest developments in this field advanced modeling techniques a modular software architecture based on inter-process communication through socket interface. choice Python for implementation rapid prototyping but can add computational overhead. In new release, we carefully benchmarked optimized several common simulation scenarios, making such overhead negligible when is used model systems up tens thousands atoms using widely adopted machine learning potentials, as Behler–Parinello, DeePMD, MACE neural networks. We also present features, including an efficient algorithm bosonic fermionic exchange, framework uncertainty quantification be conjunction infrastructure that allows deeper integration electronic-driven simulations, approach simulate coupled photon-nuclear dynamics optical or plasmonic cavities.

Language: Английский

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Spin Valley Dynamics Entangled with Optical Fields, Phonons, and Spin‐Orbit Coupling in Monolayer MoSe₂

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

Published: Feb. 6, 2025

Abstract The ab initio nonadiabatic molecular dynamics (NAMD) approach is advanced by integrating light–matter interactions, enabling comprehensive simulations of the carrier in solid materials from photoexcitation to relaxation. Using this method, excited electron and hole are investigated monolayer MoSe 2 entangled with optical field, phonons spin‐orbit coupling (SOC), encompassing valley polarization depolarization. During initial 0.6 ps after photoexcitation, field dominates, leading rapid a high‐polarization plateau, alongside phonon‐assisted intervalley photoexcitation. Subsequently, electron‐phonon interactions SOC starts play role depolarization, diminishing zero around 1.6 ps. Hole also induced it depolarizes more slowly than electrons without an but becomes dependent on when laser present. This work provides powerful tool for studying coherent effects fields, phonons, dynamics, which crucial design next‐generation optoelectronic devices.

Language: Английский

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Extending Carrier Lifetimes of Metal Halide Perovskites by Defect Passivation with Alkaline Earth Metals: A Time-Domain Study

The Journal of Physical Chemistry Letters, Journal Year: 2025, Volume and Issue: 16(9), P. 2438 - 2444

Published: Feb. 27, 2025

Intrinsic defects that serve as non-radiative recombination centers significantly accelerate charge and energy losses in hybrid organic-inorganic perovskites. The defect IMA, formed by replacing an MA with I MAPbI3 (MA = CH3NH3+), creates trimer produces a deep electron trap state. Non-adiabatic (NA) molecular dynamics simulations demonstrate excited conduction band is rapidly captured this within 100 ps, followed valence hole 1 ns, which 3 times faster than the pristine system. Doping interstitial Sr Ba eliminates state breaking trimer, thereby restoring electron-hole across bandgap to durations up 3.20 4.36 respectively. delayed attributed decreased NA coupling shortened decoherence time. These findings provide critical insights into perovskite passivation strategies alkaline earth metals.

Language: Английский

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Nuclear Quantum Effects Accelerate Hot Carrier Relaxation but Slow Down Recombination in Metal Halide Perovskites

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

Published: March 19, 2025

Inorganic semiconductors are composed of heavy elements whose vibrational motions well described by classical mechanics. Heavy elements, such as Pb and I, support charge carriers in metal halide perovskites. Nevertheless, the soft structure strong coupling between organic inorganic components create conditions which nuclear quantum effects (NQEs) can play important roles. By combining ab initio, ring-polymer, nonadiabatic molecular dynamics approaches with time-domain density functional theory, we demonstrate how NQEs influence structural electronic properties electron-vibrational hybrid organic-inorganic (MAPbI3) all-inorganic (CsPbI3) Quantum zero-point fluctuations enhance disorder, reduce band gap, accelerate elastic scattering responsible for coherence loss. have opposite influences on intraband carrier relaxation interband recombination. These inelastic events governed product overlap-like electron-phonon matrix element atomic velocity. overlap increases The involves many states. Reduction some states is offset other pathways, while an increased velocity makes faster. Electron-hole band-edge plays a key role recombination, its reduction NQEs-enhanced disorder recombination slower. This phenomenon seen both MAPbI3 CsPbI3 much more pronounced when light component present. study offers detailed understanding processes perovskites, offering theoretical insights into hot that govern performance solar cells optoelectronic devices.

Language: Английский

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Nuclear Quantum Effects Accelerate Charge Recombination but Boost the Stability of Inorganic Perovskites in Mild Humidity

Nano Letters, Journal Year: 2024, Volume and Issue: 24(11), P. 3476 - 3483

Published: March 6, 2024

Experiments have demonstrated that mild humidity can enhance the stability of CsPbBr3 perovskite, though underlying mechanism remains unclear. Utilizing ab initio molecular dynamics, ring polymer and non-adiabatic our study reveals nuclear quantum effects (NQEs) play a crucial role in stabilizing lattice rigidity perovskite while simultaneously shortening charge carrier lifetime. NQEs reduce extent geometric disorder number atomic fluctuations, diminish hole localization, thereby improve electron–hole overlap coupling. Concurrently, these significantly suppress phonon modes slow decoherence. As result, factors collectively accelerate recombination by factor 1.42 compared to scenarios excluding NQEs. The resulting sub-10 ns time scales align remarkably well with experimental findings. This research offers novel insight into how moisture resistance impacts lifetime all-inorganic perovskites.

Language: Английский

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Decoherence ensures convergence of non-adiabatic molecular dynamics with number of states

The Journal of Chemical Physics, Journal Year: 2024, Volume and Issue: 161(6)

Published: Aug. 9, 2024

Non-adiabatic (NA) molecular dynamics (MD) is a powerful approach for studying far-from-equilibrium quantum in photophysical and photochemical systems. Most NA-MD methods are developed tested with few-state models, their validity complex systems involving many states not well studied. By modeling intraband equilibration interband recombination of charge carriers MoS2, we investigate the convergence three popular algorithms, fewest switches surface hopping (FSSH), global flux (GFSH), decoherence induced (DISH) number states. Only standard DISH algorithm converges produces Boltzmann equilibrium. Unitary propagation wave function FSSH GFSH violates distribution, leads to internal inconsistency between time-dependent Schrödinger equation state populations trajectory counts, non-convergent results. Introducing by collapsing fixes these problems. The simplified version that omits projecting out occupied applicable also causes problems when increased. We discuss algorithmic application collapse detailed balance provide FSSH, GFSH, flow charts. use convergent highly important complicated processes multiple Our findings basis investigating realistic

Language: Английский

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