First-principles calculations of defects in metal halide perovskites: A performance comparison of density functionals

Xue, Haibo; Brocks, G.; Tao, Shuxia

doi:10.1103/physrevmaterials.5.125408

Cited by 19 publications

(40 citation statements)

References 71 publications

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“…The DFEs of MAPbI 3 are actually the same under Imedium and I-poor conditions, which stems from a compensation between the change in the iodine chemical potential, and the change in the intrinsic Fermi level, Sec. II C [50]. This compensation mechanism does not work if the Fermi level is not pinned, as is the case for MASnI 3 .…”

Section: Varying the M Cationmentioning

confidence: 94%

“…This functional combines the strongly constrained and appropriately normed (SCAN) [55] meta-generalized gradient approximation (meta-GGA) functional with the long-range van der Waals interactions from the revised Vydrova -van Voorhis non-local correlation functional (rVV10) [56]. It has emerged in a previous study as a reliable functional for calculating defect properties of metal halide perovskites [50].…”

Section: Computational Approach a Dft Calculationsmentioning

confidence: 99%

“…We omit spin-orbit coupling (SOC), as we have shown that SOC has little effect on the formation energies of defects [50]. Our calculations use a plane wave kinetic energy cutoff of 500 eV and a Γ-point only k-point mesh.…”

Section: Computational Approach a Dft Calculationsmentioning

confidence: 99%

“…37 and 50 we find that the 2×2×2 tetragonal supercell and the dielectric screening in AMX 3 perovskites are sufficiently large, such that this correction is small and can be neglected. We neglect vibrational contributions to the DFE as well as the influence of thermal expansion on it, as these are typically small in the present compounds [50,67].…”

Section: Defect Formation Energymentioning

confidence: 99%

“…F [50]. The intrinsic Fermi level can be determined by the charge neutrality condition, which expresses the fact that, if no charges are injected in a material, it has to be charge neutral…”

Section: Defect Formation Energymentioning

confidence: 99%

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The thermodynamic trends of intrinsic defects in primary halide perovskites: A first-principles study

Han¹,

Brocks²,

Tao³

2021

Preprint

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Defects in halide perovskites play an essential role in determining the efficiency and stability of the resulting optoelectronic devices. Here, we present a systematic study of intrinsic point defects in six primary metal halide perovskites, MAPbI3, MAPbBr3, MAPbCl3, FAPbI3, CsPbI3 and MASnI3, using density functional theory calculations with the SCAN+rVV10 functional. We analyse the impact of changing anions and cations on the defect formation energies and the charge state transitions levels and identify the physical origins underlying the observed trends. Dominant defects in the lead-iodide compounds are the A + cation interstitials (A = Cs, MA, FA), charge-compensated by I − interstitials or lead (2−) vacancies. In the lead-bromide and -chloride compounds, halide vacancies become relatively more prominent, and for MAPbBr3, the Pb 2+ interstitial also becomes important. The trends can be explained in terms of the changes in electrostatic interactions and chemical bonding upon replacing cations and anions. Defect physics in MASnI3 is strongly dominated by tin (2−) vacancies, promoted by the easy oxidation of the tin perovskite. Intrinsically, all compounds are mildly p-doped, except for MASnI3, which is strongly p-doped. All acceptor levels created by defects in the six perovskites are shallow. Some defects, halide vacancies and Pb or Sn interstitials in particular, create deep donor traps. Although these traps might hamper the electronic behavior of MAPbBr3 and MAPbCl3, in iodine-based perovskites their equilibrium concentrations are too small to affect the materials' properties.

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Section: Varying the M Cationmentioning

confidence: 94%

Section: Computational Approach a Dft Calculationsmentioning

confidence: 99%

Section: Computational Approach a Dft Calculationsmentioning

confidence: 99%

Section: Defect Formation Energymentioning

confidence: 99%

Section: Defect Formation Energymentioning

confidence: 99%

See 3 more Smart Citations

The thermodynamic trends of intrinsic defects in primary halide perovskites: A first-principles study

Han¹,

Brocks²,

Tao³

2021

Preprint

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Diammonium‐Mediated Perovskite Film Formation for High‐Luminescence Red Perovskite Light‐Emitting Diodes

Apergi

Chan

et al. 2022

Advanced Materials

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degradation caused by heat and electric field during intensive current stressing remain detrimental for the performance of PeLEDs and hinder the commercialization of this technology.Red-emitting PeLEDs are a critical component for both display and biomedical applications. One of the most popular strategies to combat instability in red perovskite emitters is dimension regulation. Highly efficient red PeLEDs have been fabricated by employing perovskite quantum dots (QDs) and multiple quantum well (MQW) perovskites to manipulate emission wavelength and confine excitons. [3][4][5][6][7] However, the hot-injection synthesis and post treatment of QDs require complex processing and high efficiencies can only be achieved at a low current density. The quantum-well width in MQW perovskites also needs to be finely regulated to avoid small-n phases and guarantee efficient energy transfer. [8,9] 3D perovskites converted directly from precursor mixtures would be more desirable because of simple fabrication and efficient charge transport. A mixture of bromide and iodide ions is generally required to construct 3D perovskite lattices that emit red light. In this case the formation of defects during the 3D film formation is almost inevitable. Various passivation strategies have been developed to address this issue and improved both the device efficiency by removing nonradiative 3D mixed-halide perovskite-based red emitters combine excellent chargetransport characteristics with simple solution processing and good film formation; however, light-emitting diodes (LEDs) based on these emitters cannot yet outperform their nanocrystal counterparts. Here the use of diammonium halides in regulating the formation of mixed bromide-iodide perovskite films is explored. It is found that the diammonium cations preferentially bond to Pb-Br, rather than Pb-I, octahedra, promoting the formation of quasi-2D phases. It is proposed that the perovskite formation is initially dominated by the crystallization of the thermodynamically more favorable 3D phase, but, as the solution gets depleted from the regular A cations, thin shells of amorphous quasi-2D perovskites form. This leads to crystalline perovskite grains with efficiently passivated surfaces and reduced lattice strain. As a result, the diammonium-treated perovskite LEDs demonstrate a record luminance (10745 cd m −2 ) and half-lifetime among 3D perovskitebased red LEDs.

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Unveiling the Effect of Cooling Rate on Grown‐in Defects Concentration in Polycrystalline Perovskite Films for Solar Cells with Improved Stability

Yin,

Chen,

Xie

et al. 2024

Advanced Materials

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Numerous efforts are devoted to reducing the defects at perovskite surface and/or grain boundary; however, the grown‐in defects inside grain is rarely studied. Here, the influence of cooling rate on the point defects concentration in polycrystalline perovskite film during heat treatment processing is investigated. With the combination of theoretical and experimental studies, this work reveals that the supersaturated point defects in perovskite films generate during the cooling process and its concentration improves as the cooling rate increases. The supersaturated point defects can be minimized through slowing the cooling rate. As a result, the optimized FAPbI3 polycrystalline films achieve a superior carrier lifetime of up to 12.6 µs and improved stability. The champion device delivers a 25.47% PCE (certified 24.7%) and retain 90% of their initial value after >1100 h of operation at the maximum power point. These results provide a fundamental understanding of the mechanisms of grown‐in defects formation in polycrystalline perovskite film.

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First-principles calculations of defects in metal halide perovskites: A performance comparison of density functionals

Cited by 19 publications

References 71 publications

The thermodynamic trends of intrinsic defects in primary halide perovskites: A first-principles study

The thermodynamic trends of intrinsic defects in primary halide perovskites: A first-principles study

Diammonium‐Mediated Perovskite Film Formation for High‐Luminescence Red Perovskite Light‐Emitting Diodes

Unveiling the Effect of Cooling Rate on Grown‐in Defects Concentration in Polycrystalline Perovskite Films for Solar Cells with Improved Stability

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