Structural Disorder in Higher-Temperature Phases Increases Charge Carrier Lifetimes in Metal Halide Perovskites

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(41), P. 19137 - 19149

Published: Oct. 7, 2022

Solar cells and optoelectronic devices are exposed to heat that degrades performance. Therefore, elucidating temperature-dependent charge carrier dynamics is essential for device optimization. Charge lifetimes decrease with temperature in conventional semiconductors. The opposite, anomalous trend observed some experiments performed MAPbI3 (MA = CH3NH3+) other metal halide perovskites. Using ab initio quantum simulation, we establish the atomic mechanisms responsible nonradiative electron-hole recombination orthorhombic-, tetragonal-, cubic MAPbI3. We demonstrate structural disorder arising from phase transitions as important due heating same phase. grow both increasing upon transition higher-temperature phases. increased lifetime rationalized by induces partial localization, decreases nonadiabatic coupling, shortens coherence. Inelastic elastic electron-vibrational interactions exhibit opposite dependence on localization arise thermal motions of inorganic lattice organic cations depend significantly deformations induced fluctuations order defects, hence, plays a very role. Since increases but inhibits transport, an optimal regime maximizing diffusion can be designed, depending phase, temperature, material morphology, architecture. atomistic enhanced at elevated temperatures provide guidelines design improved solar energy materials.

Language: Английский

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Rapid Interlayer Charge Separation and Extended Carrier Lifetimes due to Spontaneous Symmetry Breaking in Organic and Mixed Organic–Inorganic Dion–Jacobson Perovskites

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(9), P. 5297 - 5309

Published: Feb. 24, 2023

Promising alternatives to three-dimensional perovskites, two-dimensional (2D) layered metal halide perovskites have proven their potential in optoelectronic applications due improved photo- and chemical stability. Nevertheless, photovoltaic devices based on 2D suffer from poor efficiency owing unfavorable charge carrier dynamics energy losses. Focusing the Dion-Jacobson perovskite phase that is rapidly rising popularity, we demonstrate doping of complementary cations into 3-(aminomethyl)piperidinium accelerates spontaneous separation slows down recombination, both factors improving performance. Employing ab initio nonadiabatic (NA) molecular combined with time-dependent density functional theory, cesium broadens bandgap by 0.4 eV breaks structural symmetry. Assisted thermal fluctuations, symmetry breaking helps localize electrons holes different layers activates additional vibrational modes. As a result, accelerated. Simultaneously, lifetime grows shortened coherence time between ground excited states. The established relationships composition provide guidelines toward future material discovery design solar cells.

Language: Английский

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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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How Hole Injection Accelerates Both Ion Migration and Nonradiative Recombination in Metal Halide Perovskites

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(14), P. 6604 - 6612

Published: April 1, 2022

Ion migration, hole trapping, and electron-hole recombination are common processes in metal halide perovskites. We demonstrate using ab initio non-adiabatic molecular dynamics time-domain density functional theory that they intricately related strongly influence each other. The injection accelerates ion migration by decreasing the diffusion barrier shortening length. injected also promotes nonradiative charge strengthening electron-phonon interactions low-frequency region prolonging quantum coherence time. synergy stems from soft perovskite lattice response of valence band maximum to Pb-I distortion induced hole. This work provides important insights into mobility on performance solar cells suggests high concentration holes should be avoided.

Language: Английский

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Suppressing Oxygen-Induced Deterioration of Metal Halide Perovskites by Alkaline Earth Metal Doping: A Quantum Dynamics Study

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(12), P. 5543 - 5551

Published: March 16, 2022

Exposure to oxygen undermines stability and charge transport in metal halide perovskites, because molecular oxygen, as well photogenerated superoxide peroxide, erodes the perovskite lattice creates traps. We demonstrate that alkaline earth metals passivate species CH3NH3PbI3 by breaking O-O bond forming new bonds with atoms, shifting trap states of antibonding orbitals from inside bandgap into bands. In addition eliminating oxidizing traps, doping slightly increases partially localizes electron hole wavefunctions, weakening electron-hole charge-phonon interactions making carrier lifetimes longer than even those pristine CH3NH3PbI3. Relative exposed light, lifetime passivated 2-3 orders magnitude. The ab initio quantum dynamics simulations efficiently not only intrinsic defects, but also foreign species, providing a viable strategy suppress degradation.

Language: Английский

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Nuclear Quantum Effects Prolong Charge Carrier Lifetimes in Hybrid Organic–Inorganic Perovskites

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(25), P. 14112 - 14123

Published: June 19, 2023

Hybrid organic-inorganic perovskites (HOIPs) contain light hydrogen atoms that exhibit significant nuclear quantum effects (NQEs). We demonstrate NQEs have a strong effect on HOIP geometry and electron-vibrational dynamics at both low ambient temperatures, even though charges in HOIPs reside heavy elements. By combining ring-polymer molecular (MD) ab initio MD with nonadiabatic time-dependent density functional theory focusing the most studied tetragonal CH3NH3PbI3, we show increase disorder thermal fluctuations through coupling of inorganic cations to lattice. The additional induces charge localization decreases electron-hole interactions. As result, nonradiative carrier lifetimes are extended by factor 3 160 K 1/3 330 K. radiative increased 40% temperatures. fundamental band gap 0.10 0.03 eV K, respectively. enhancing atomic motions introducing new vibrational modes, strengthen Decoherence, determined elastic scattering, accelerates almost 2 due NQEs. However, coupling, driving recombination, because it is more sensitive structural distortions than HOIPs. This study demonstrates, for first time, should be considered achieve an accurate understanding evolution provides important insights design related materials optoelectronic applications.

Language: Английский

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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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Breaking the size limitation of nonadiabatic molecular dynamics in condensed matter systems with local descriptor machine learning

Proceedings of the National Academy of Sciences, Journal Year: 2024, Volume and Issue: 121(36)

Published: Aug. 30, 2024

Nonadiabatic molecular dynamics (NA-MD) is a powerful tool to model far-from-equilibrium processes, such as photochemical reactions and charge transport. NA-MD application condensed phase has drawn tremendous attention recently for development of next-generation energy optoelectronic materials. Studies matter allow one employ efficient computational tools, density functional theory (DFT) classical path approximation (CPA). Still, system size simulation timescale are strongly limited by costly ab initio calculations electronic energies, forces, NA couplings. We resolve the limitations developing fully machine learning (ML) approach in which all above properties obtained using neural networks based on local descriptors. The ML models correlate target NA-MD, implemented with DFT CPA, directly structure. Trained small systems, applied large systems long timescales, extending capabilities orders magnitude. demonstrate dependence trapping recombination defect concentration MoS 2 . Defects provide main mechanism losses, resulting performance degradation. Charge slows decreasing concentration; however, exhibits complex dependence, conditional whether it occurs between free or trapped charges, relative concentrations carriers defects. Delocalized shallow traps can become localized increasing temperature, changing behavior. Completely ML, bridges gap theoretical realistic experimental conditions enables thousand-atom many nanoseconds.

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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