Band Gap Narrowing in Lead-Halide Perovskites by Dynamic Defect Self-Doping for Enhanced Light Absorption and Energy Upconversion

Chemistry of Materials, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 6, 2025

Metal halide perovskites (MHP) have attracted great attention in the photovoltaic industry due to their high and rapidly rising power conversion efficiencies, currently over 25%. However, hybrid organic-inorganic MHPs are inherently chemically unstable, limiting application. All-inorganic perovskites, such as CsPbI3, many merits, but stable efficiency is lower, around 18%, a larger band gap causing mismatch with solar spectrum. Choosing α-CsPbI3 prototypical system, we demonstrate new general concept of dynamic defects that fluctuate between deep shallow states, increase range absorbed photons, without accelerating nonradiative electron-hole recombination. In deeper energy state, narrow allow harvesting light longer wavelengths. Fluctuating shallower energies, escape photogenerated charges into bands, enabling charge transport resulting defect-mediated upconversion thermal electricity. Defect covalency participation low-frequency anharmonic vibrations decouple trapped from free carriers, minimizing carrier losses. Our findings defect dynamics unique important properties MHPs, can be used optimize for efficient optoelectronic applications.

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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Detrimental Defect Cooperativity at TiO₂/CH₃NH₃PbI₃ Interface: Decreased Stability, Enhanced Ion Diffusion, and Reduced Charge Lifetime and Transport

ACS Energy Letters, Journal Year: 2024, Volume and Issue: unknown, P. 5888 - 5897

Published: Nov. 18, 2024

Interfaces are essential for solar cell performance since they govern charge separation and transport. Using quantum dynamics simulation, we demonstrate that at interfaces, common defects benign on their own, iodine vacancy in CH3NH3PbI3 (VI) oxygen TiO2 (VO), responsible synergistically poor stability losses. VO promotes VI diffusion accelerates migration. A midgap trap state appears, inhibiting transport accelerating recombination by an order of magnitude. Strong structural distortions strengthen electron-vibrational interactions activate high-frequency phonons. Because the widely reported high defect-tolerance lead-halide perovskites, synergistic detrimental influence perovskite with other materials is often overlooked. The interfacial defect pairing could be a major reason losses cells. results suggest either high-quality or extraction layer may sufficient to achieve performance.

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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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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Enhancement of hole capture and water dissociation on rutile TiO₂(110) by intermolecular hydrogen bonding: time-domain ab initio study

Journal of Materials Chemistry A, Journal Year: 2024, Volume and Issue: 12(38), P. 26178 - 26187

Published: Jan. 1, 2024

Enhanced intermolecular hydrogen bonds accelerate photogenerated hole capture and water dissociation.

Language: Английский

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Formation and Recombination Dynamics of Polarons in Goethite: A Time-Domain Ab Initio Study

The Journal of Physical Chemistry Letters, Journal Year: 2024, Volume and Issue: unknown, P. 10018 - 10025

Published: Sept. 25, 2024

The temperature and the coordination environment significantly affect polaron dynamics. Using goethite (FeOOH) as a model, our study examines formation recombination behavior under various conditions, including electron injection, photoexcitation, heterovalent doping. Ab initio nonadiabatic molecular dynamics (NAMD) simulations reveal that in FeOOH is dependent on via an adiabatic mechanism with higher temperatures leading to shorter times. Only polarons form FeOOH, regardless of method. NAMD indicate photoexcited faster than Fe

Language: Английский

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Nonradiative Charge Recombination Dynamics in Fully Hydroxylated Hematite Surface: A Time-Domain Ab Initio Study

The Journal of Physical Chemistry C, Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 3, 2024

Hematite (α-Fe2O3) is a typical semiconducting transition metal oxide that exhibits attractive properties for photoelectrochemical (PEC) water splitting and other applications. However, it has been widely reported charge recombination in α-Fe2O3 photoanodes serious problem, hindering further improvement the efficiency of PEC splitting. We used ab initio nonadiabatic molecular dynamics (NAMD) to investigate bulk surface phases α-Fe2O3. The NAMD simulations employ decoherence-induced hopping (DISH) method implemented within time-dependent density functional theory. test demonstrate need incorporate both phase-consistency correction all-electron calculation NA coupling, latter needed metals with d-shell electrons. show time scale intrinsic can reach microseconds, accordance existence long-lived photogenerated carriers observed transient absorption measurements on electrodes. hydroxylated iron-termination α-Fe2O3(0001) surface, one most stable surfaces aqueous solution, much faster recombination, about 1 order magnitude compared key factor fast mainly be assigned strong fluctuations NAC energy gap between conduction band minimum (CBM) valence maximum (VBM) quantum anti-Zeno effect. This work extends from phase interfacial α-Fe2O3, approaching reaction conditions, thus assists understanding underlying oxygen evolution (OER) at Fe2O3–water interface design new efficient Fe2O3-based photoanode materials.

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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Orbital hybridization induces fast photoelectron capture by graphene to promote high gain in transition metal dichalcogenide/graphene heterojunctions

Physical review. B./Physical review. B, Journal Year: 2024, Volume and Issue: 110(24)

Published: Dec. 2, 2024

Transition metal dichalcogenide/graphene (TMDC/Gr) heterojunction devices exhibit significantly higher photoresponsivity compared to TMDC alone, making them promising for optoelectronic applications. However, experiments demonstrated that graphene cannot prolong the photogenerated carrier lifetime of TMDC/Gr heterojunctions and, further, high density sulfur vacancies in TMDCs complicates dynamics, leaving underlying physical mechanism behind unclear. Herein, we investigate transfer and recombination $\mathrm{Mo}{\mathrm{S}}_{2}$/Gr $\mathrm{W}{\mathrm{S}}_{2}$/Gr through nonadiabatic molecular dynamics simulations. Instead conventional speculation store carriers enhance performance, find hybridization between defect states Dirac points induces fast photoelectron from graphene, promoting gain heterojunctions. Fast derives excitation low-frequency in-plane phonon modes. Meanwhile, does not drastically reduce Therefore, faster electrons long lead gain, resulting superior performance This study provides a comprehensive understanding heterojunctions, laying foundation design high-performance devices.

Language: Английский

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