Understanding Defects in Perovskite Solar Cells through Computation: Current Knowledge and Future Challenge

Advanced Science, Journal Year: 2024, Volume and Issue: 11(20)

Published: March 19, 2024

Abstract Lead halide perovskites with superior optoelectrical properties are emerging as a class of excellent materials for applications in solar cells and light‐emitting devices. However, perovskite films often exhibit abundant intrinsic defects, which can limit the efficiency perovskite‐based optoelectronic devices by acting carrier recombination centers. Thus, an understanding defect chemistry lead assumes prominent role further advancing exploitation perovskites, which, to large extent, is performed relying on first‐principles calculations. complex structure, strong anharmonicity, soft lattice pose challenges studies. In this perspective, basis briefly reviewing current knowledge concerning computational studies work concentrates addressing unsolved problems proposing possible research directions future. This perspective particularly emphasizes indispensability developing advanced approaches deeply nature defects conducting data‐driven designing reasonable strategies improve performance applications. Finally, highlights that theoretical should pay more attention establishing close clear links experimental investigations provide useful insights scientific industrial communities.

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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Halide Vacancies Create No Charge Traps on Lead Halide Perovskite Surfaces but Can Generate Deep Traps in the Bulk

The Journal of Physical Chemistry Letters, Journal Year: 2023, Volume and Issue: 14(26), P. 6028 - 6036

Published: June 23, 2023

Metal halide perovskites (MHPs) have attracted attention because of their high optoelectronic performance that is fundamentally rooted in the unusual properties MHP defects. By developing an ab initio-based machine-learning force field, we sample structural dynamics MHPs on a nanosecond time scale and show vacancies create midgap trap states bulk but not surface. Deep traps result from Pb-Pb dimers can form across vacancy only bulk. The required shortening distance by nearly 3 Å facilitated either charge trapping or 50 ps thermal fluctuations. large-scale deformations are possible soft. Halide surface no deep separate electrons holes, keeping charges mobile. This particularly favorable for quantum dots, which do require sophisticated passivation to emit light blink less than dots formed traditional inorganic semiconductors.

Language: Английский

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Compression Eliminates Charge Traps by Stabilizing Perovskite Grain Boundary Structures: An Ab Initio Analysis with Machine Learning Force Field

Chemistry of Materials, Journal Year: 2024, Volume and Issue: 36(6), P. 2898 - 2906

Published: March 12, 2024

Grain boundaries (GBs) play an important role in determining the optoelectronic properties of perovskites, requiring atomistic understanding underlying mechanisms. Strain engineering has recently been employed perovskite solar cells, providing a novel perspective on GBs. Here, we theoretically investigate impact axial strain geometric and electronic common CsPbBr3 GB. We develop machine learning force field perform ab initio calculations to analyze behavior GB models with different strains nanosecond time scale. Our results demonstrate that compressing efficiently suppresses structural fluctuations eliminates trap states originating from large-scale distortions. The becomes more amorphous under compressive strain, which makes relationship between structure nonmonotonic. These can help clarify conflicts experiments.

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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Photocatalytic activity of dual defect modified graphitic carbon nitride is robust to tautomerism: machine learning assisted ab initio quantum dynamics

Nanoscale, Journal Year: 2024, Volume and Issue: 16(18), P. 8986 - 8995

Published: Jan. 1, 2024

Transformations between multiple tautomeric forms of defective graphitic carbon nitride occur on nanosecond timescales, but these transformations have little influence charge carrier lifetimes.

Language: Английский

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Machine learning accelerated nonadiabatic dynamics simulations of materials with excitonic effects

The Journal of Chemical Physics, Journal Year: 2025, Volume and Issue: 162(2)

Published: Jan. 8, 2025

This study presents an efficient methodology for simulating nonadiabatic dynamics of complex materials with excitonic effects by integrating machine learning (ML) models simplified Tamm–Dancoff approximation (sTDA) calculations. By leveraging ML models, we accurately predict ground-state wavefunctions using unconverged Kohn–Sham (KS) Hamiltonians. These ML-predicted KS Hamiltonians are then employed sTDA-based excited-state calculations (sTDA/ML). The results demonstrate that energies, time-derivative couplings, and absorption spectra from sTDA/ML accurate enough compared those conventional density functional theory based sTDA (sTDA/DFT) Furthermore, sTDA/ML-based molecular simulations on two different systems, namely chloro-substituted silicon quantum dot monolayer black phosphorus, achieve more than 100 times speedup the linear response time-dependent DFT simulations. work highlights potential ML-accelerated studying complicated photoinduced large offering significant computational savings without compromising accuracy.

Language: Английский

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Entropy: A controversy between experiment and calculations in grain boundary segregation

Progress in Materials Science, Journal Year: 2025, Volume and Issue: unknown, P. 101431 - 101431

Published: Jan. 1, 2025

Language: Английский

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Modular development of deep potential for complex solid solutions

Physical review. B./Physical review. B, Journal Year: 2023, Volume and Issue: 107(14)

Published: April 12, 2023

The multicomponent oxide solid solution is a versatile platform to tune the delicate balance between competing spin, charge, orbital, and lattice degrees of freedom for materials design discovery. development compositionally complex oxides with superior functional properties has been largely empirical serendipitous, in part due exceedingly chemistry structure solutions that span range length scales. usage classical molecular dynamics (MD), powerful statistical method, computer-aided not yet reached same level sophistication as drug because limited availability accuracy force fields solids. Here, we introduce strategy ``modular deep potential'' (ModDP) enables systematic improvement deep-neural-network-based model potential, termed minimum human intervention. converged training database associated an end-member material treated independent module reused train potential via concurrent learning procedure. We apply ModDP obtain two technologically important solutions, ${\mathrm{Pb}}_{x}{\mathrm{Sr}}_{1\ensuremath{-}x}{\mathrm{TiO}}_{3}$ ${\mathrm{Hf}}_{x}{\mathrm{Zr}}_{1\ensuremath{-}x}{\mathrm{O}}_{2}$. For both materials' systems, single capable predicting various including temperature-driven composition-driven phase transitions over wide compositions. In particular, reproduces few known topological textures such polar vortex electric dipole waves ${\mathrm{PbTiO}}_{3}/{\mathrm{SrTiO}}_{3}$ superlattices, paving way MD investigations on structures response external stimuli. simulations ${\mathrm{Hf}}_{x}{\mathrm{Zr}}_{1\ensuremath{-}x}{\mathrm{O}}_{2}$ reveal substantial impact composition variation transition temperature nature high-temperature nonpolar phase.

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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