Modeling with Hybrid Density Functional Theory the Electronic Band Alignment at the Zinc Oxide–Anatase Interface

Conesa, J.C.

doi:10.1021/jp306160c

Cited by 80 publications

(72 citation statements)

References 54 publications

(80 reference statements)

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“…It has been proposed on the basis of GW-type theory and checked for several semiconductors [21,[25][26][27][28][29] that for the PBE0 functional, the optimal fraction of exact exchange to reproduce band gaps can be determined as α = 1/ ∞ , where ∞ is the electronic (high-frequency) dielectric constant, which should be computed in self-consistency with α [27]. In the present work, the dielectric constant has been obtained computing the electric polarization under an external electric field, by means of the Berry phase theory [30][31][32].…”

Section: Methodsmentioning

confidence: 99%

Self-consistent relativistic band structure of theCH3NH3PbI3perovskite

et al. 2014

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The electronic structure and properties of the orthorhombic phase of the CH 3 NH 3 PbI 3 perovskite are computed with density functional theory. The structure, optimized using a van der Waals functional, reproduces closely the unit cell volume. The experimental band gap is reproduced accurately by combining spin-orbit effects and a hybrid functional in which the fraction of exact exchange is tuned self-consistently to the optical dielectric constant. Including spin-orbit coupling strongly reduces the anisotropy of the effective mass tensor, predicting a low electron effective mass in all crystal directions. The computed binding energy of the unrelaxed exciton agrees with experimental data, and the values found imply a fast exciton dissociation at ambient temperature. Also polaron masses for the separated carriers are estimated. The values of all these parameters agree with recent indications that fast dynamics and large carrier diffusion lengths are key in the high photovoltaic efficiencies shown by these materials.

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Section: Methodsmentioning

confidence: 99%

Self-consistent relativistic band structure of theCH3NH3PbI3perovskite

et al. 2014

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“…To obtain the valence-and conduction-band discontinuities, we used an electrostatic potential-based alignment method [9,26] following a three-step computational procedure. The first step is the determination of the appropriate a value for each bulk semiconductor, carried out as said above.…”

Section: Model and Computational Techniquementioning

confidence: 99%

Electronic band alignment at CuGaS2 chalcopyrite interfaces

Castellanos-Águila

Palacios

Conesa

et al. 2016

Computational Materials Science

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Cu-chalcopyrite semiconductors are commonly used as light absorbing materials on solar cell devices. The study of the heterointerfaces between the absorbent and the contact materials is crucial to understand their operation. In this study, band alignments of the heterojunctions between CuGaS 2 chalcopyrite and different semiconductors have been theoretically obtained using density functional theory and more advanced techniques. Band alignments have been determined using the average electrostatic potential as reference level. We have found that the strain in the heterointerfaces plays an important role in the electronic properties of the semiconductors employed here. In this work CuAlSe 2 /CuGaS 2 and CuGaS 2 /ZnSe heterointerfaces show band alignments where holes and electrons are selectively transferred through the respective heterojunctions to the external contacts. This condition is necessary for their application on photovoltaic devices.

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“…A similar approach has been followed by Conesa with the aim of properly aligning the VB and CB edges of two interfaced semiconducting oxides, specifically anatase TiO 2 and ZnO [63]. In this approach the mixing parameter a has been fitted to the experimental dielectric constant (a = 1/e ? )…”

Section: The Band Gap and Band Alignment Problemmentioning

confidence: 99%

“…In this way, not only the band gaps of the two oxides have been properly reproduced, but it was also possible to find that the conduction and valence bands of ZnO will lie ca. 0.3 eV lower in energy than those of anatase, influencing the way in which photogenerated electrons and holes will be routed in photocatalytic systems which include interfaces between these two oxides [63]. What is probably the most detailed and extended analysis of the band alignment problem for an oxide semiconductor has been recently reported by Migani et al for the case of methanol adsorption on rutile TiO 2 (110) [64,65].…”

Section: The Band Gap and Band Alignment Problemmentioning

confidence: 99%

First Principles Calculations on Oxide-Based Heterogeneous Catalysts and Photocatalysts: Problems and Advances

Pacchioni

2014

Catal Lett

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Density functional theory (DFT) has become an essential complement of experiments to interpret, rationalize, and understand structures, spectroscopic data, microscopy analyses, etc. of relevance in heterogeneous catalysis and photocatalysis. However, one of the major goals of theory in catalysis remains the prediction of reaction enthalpies and entropies, of transition state structures, and the identification of reaction mechanisms. While accurate theoretical methods are currently available to study the thermochemistry of molecular systems, this is much less so when reactions involve solid surfaces and in particular oxide materials. The problem stems from the approximate nature of the exchange-correlation functionals used in all DFT approaches. Attempts to improve the accuracy of reaction energies is at the core of the efforts made in the past 30 years to generate new functionals. In this review we will discuss some recent advances in the theoretical description of oxides and their surfaces in heterogeneous catalysis and photocatalysis. In particular, we will focus on two problems: (1) the determination of an oxide band gap and the proper alignment of the occupied and unoccupied levels with respect to the vacuum level, an aspect relevant for the red-ox properties of the material, and (2) the calculation of reaction energies at oxide surfaces. To this end, we will discuss and comment on the performance of current implementations of exchange-correlation functionals (standard GGA, GGA?U, hybrid functionals, meta-GGA, etc.) or alternative approaches (like the quasiparticle GW method), in predicting band alignment and chemical reactivity at oxide surfaces. The role of dispersion forces will be also briefly discussed.

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Modeling with Hybrid Density Functional Theory the Electronic Band Alignment at the Zinc Oxide–Anatase Interface

Cited by 80 publications

References 54 publications

Self-consistent relativistic band structure of theCH3NH3PbI3perovskite

Self-consistent relativistic band structure of theCH3NH3PbI3perovskite

Electronic band alignment at CuGaS2 chalcopyrite interfaces

First Principles Calculations on Oxide-Based Heterogeneous Catalysts and Photocatalysts: Problems and Advances

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