Nonempirical hybrid functionals for band gaps of inorganic metal-halide perovskites

Bischoff, Thomas; Wiktor, Julia; Chen, Wei; Pasquarello, Alfredo

doi:10.1103/physrevmaterials.3.123802

Cited by 48 publications

(54 citation statements)

References 71 publications

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“…However, an alternative is represented by the dielectric‐dependent (DD) functionals where the amount of exact exchange is obtained self‐consistently from the dielectric constant of the material. [ 45 , 46 , 47 , 48 , 49 , 50 ] In a recent study we compared the performances of various popular hybrid functionals, including standard (PBE0, B3LYP, HSE06, etc.) and dielectric‐dependent (DD) functionals.…”

Section: Methodological Aspectsmentioning

confidence: 99%

Rational Design of Semiconductor Heterojunctions for Photocatalysis

Liberto

Cipriano

Tosoni

et al. 2021

Chemistry A European J

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Electronic structure calculations provide a useful complement to experimental characterization tools in the atomic-scale design of semiconductor heterojunctions for photocatalysis. The band alignment of the heterojunction is of fundamental importance to achieve an efficient charge carrier separation, so as to reduce electron/hole recombination and improve photoactivity. The accurate prediction of the offsets of valence and conduction bands in the constituent units is thus of key importance but poses several methodological and practical problems. In this Minireview we address some of these problems by considering selected examples of binary and ternary semiconductor heterojunctions and how these are determined at the level of density functional theory (DFT). The atomically precise description of the interface, the consequent charge polarization, the role of quantum confinement, the possibility to use facet engineering to determine a specific band alignment, are among the effects discussed, with particular attention to pros and cons of each one of these aspects. This analysis shows the increasingly important role of accurate electronic structure calculations to drive the design and the preparation of new interfaces with desired properties.

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Section: Methodological Aspectsmentioning

confidence: 99%

Rational Design of Semiconductor Heterojunctions for Photocatalysis

Liberto

Cipriano

Tosoni

et al. 2021

Chemistry A European J

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“…However, it is important to mention that this screening parameter in hybrids can be computed ab initio (see, e.g., Refs. [13,15,18]), which is not always an easy task. In this case, an extra computational cost for HSE06 must be added in Table A2 which will make the ratio t HSE06 /t U even larger.…”

Section: Appendix B Computational Cost Comparison Of Hse06 and Hubbard Parameter Calculationsmentioning

confidence: 99%

“…The drawback of this method is its very high computational cost (which prevents its wider application to high-throughput computational studies [12]), and difficulties in determining the magnitude of the screening parameter for solids (that controls the amount of the exact exchange), although there has been considerable progress in this direction in recent years (see, e.g., Refs. [13][14][15][16][17][18]). In parallel, a range of computationally efficient meta-GGA functionals have emerged [19], including the strongly constrained and appropriately normed semilocal density functional (SCAN) [20].…”

Section: Introductionmentioning

confidence: 99%

Extensive Benchmarking of DFT+U Calculations for Predicting Band Gaps

et al. 2021

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Accurate computational predictions of band gaps are of practical importance to the modeling and development of semiconductor technologies, such as (opto)electronic devices and photoelectrochemical cells. Among available electronic-structure methods, density-functional theory (DFT) with the Hubbard U correction (DFT+U) applied to band edge states is a computationally tractable approach to improve the accuracy of band gap predictions beyond that of DFT calculations based on (semi)local functionals. At variance with DFT approximations, which are not intended to describe optical band gaps and other excited-state properties, DFT+U can be interpreted as an approximate spectral-potential method when U is determined by imposing the piecewise linearity of the total energy with respect to electronic occupations in the Hubbard manifold (thus removing self-interaction errors in this subspace), thereby providing a (heuristic) justification for using DFT+U to predict band gaps. However, it is still frequent in the literature to determine the Hubbard U parameters semiempirically by tuning their values to reproduce experimental band gaps, which ultimately alters the description of other total-energy characteristics. Here, we present an extensive assessment of DFT+U band gaps computed using self-consistent ab initioU parameters obtained from density-functional perturbation theory to impose the aforementioned piecewise linearity of the total energy. The study is carried out on 20 compounds containing transition-metal or p-block (group III-IV) elements, including oxides, nitrides, sulfides, oxynitrides, and oxysulfides. By comparing DFT+U results obtained using nonorthogonalized and orthogonalized atomic orbitals as Hubbard projectors, we find that the predicted band gaps are extremely sensitive to the type of projector functions and that the orthogonalized projectors give the most accurate band gaps, in satisfactory agreement with experimental data. This work demonstrates that DFT+U may serve as a useful method for high-throughput workflows that require reliable band gap predictions at moderate computational cost.

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“…Among them, several focus on calculations based on MBPT, [ 11–14 ] others employ HSE [ 15,16 ] or aim at improving hybrid functionals by tuning their parameters. [ 17,18 ] Here, we place a focus on the dependency of the results on the functionals' parameters. In particular, we apply the dielectric dependent hybrid (DDH) method [ 19 ] and the density‐based mixing (DM) method.…”

Section: Introductionmentioning

confidence: 99%

Electronic Structure of (Organic‐)Inorganic Metal Halide Perovskites: The Dilemma of Choosing the Right Functional

Vona

Nabok

Draxl

2021

Advcd Theory and Sims

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Organic–inorganic metal halide perovskites (HaPs) are intensively studied for their light‐harvesting properties. Owing to the interplay between strong electron–electron interaction and spin‐orbit coupling (SOC), their quantitative theoretical description is still a challenge as evidenced by the wide variety of results available in literature. Here, various methodologies for computing their electronic structure are evaluated, also accounting for SOC. More specific, the GW$GW$ approach as well as variants of the hybrid functionals PBE0 and HSE are at the center of the investigations. For both functionals, methods to determine the mixing parameter α are explored, and for HSE, the impact of the screening‐parameter ω is investigated. An extensive investigation of PbI2, a precursor of many HaPs, leads to the conclusion that hybrid functionals with α tuned by the density‐based mixing method are most suitable for obtaining band gaps comparable to G0W0$G_0W_0$ results. Moreover, this methodology is transferable to CsPbI3, and the same behavior is expected for the entire family of lead–iodine perovskites.

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Nonempirical hybrid functionals for band gaps of inorganic metal-halide perovskites

Cited by 48 publications

References 71 publications

Rational Design of Semiconductor Heterojunctions for Photocatalysis

Rational Design of Semiconductor Heterojunctions for Photocatalysis

Extensive Benchmarking of DFT+U Calculations for Predicting Band Gaps

Electronic Structure of (Organic‐)Inorganic Metal Halide Perovskites: The Dilemma of Choosing the Right Functional

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