Structure and properties of intrinsic and extrinsic defects in black phosphorus

Gaberle, Julian; Shluger, Alexander L.

doi:10.1039/c8nr06640j

Cited by 47 publications

(38 citation statements)

References 42 publications

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“…In addition, thermal annealing in this temperature region also facilitate the formation of extra vacancies as the anchor sites as supported by our scanning tunneling microscopy study of bulk BP (Figures S2,S3, Supporting Information). [32,33] Subsequently, metal organic precursors are deposited and anchored in the vacancy sites of BP flakes to form the metal-phosphorus bonding through the partial removal of organic ligands. Finally, a further ozone (O 3 ) treatment of these samples allows for the removal of the remaining ligands of deposited metal precursors to expose the anchored single atoms on BP.…”

Section: Resultsmentioning

confidence: 99%

Zero‐Valent Palladium Single‐Atoms Catalysts Confined in Black Phosphorus for Efficient Semi‐Hydrogenation

Chen

Yam

et al. 2021

Advanced Materials

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Single‐atom catalysts (SACs) represent a new frontier in heterogeneous catalysis due to their remarkable catalytic properties and maximized atomic utilization. However, single atoms often bond to the support with polarized electron density and thus exhibit a high valence state, limiting their catalytic scopes in many chemical transformations. Here, it is demonstrated that 2D black phosphorus (BP) acts as giant phosphorus (P) ligand to confine a high density of single atoms (e.g., Pd1, Pt1) via atomic layer deposition. Unlike other 2D materials, BP with relatively low electronegativity and buckled structure favors the strong confinement of robust zero‐valent palladium SACs in the vacancy site. Metallic Pd1/BP SAC shows a highly selective semi‐hydrogenation of phenylacetylene toward styrene, distinct from metallic Pd nanoparticles that facilitate the formation of fully hydrogenated products. Density functional theory calculations reveal that Pd atom forms covalent‐like bonding with adjacent P atoms, wherein H atoms tend to adsorb, aiding the dissociative adsorption of H2. Zero‐valent Pd in the confined space favors a larger energy gain for the synthesis of partially hydrogenated product over the fully hydrogenated one. This work provides a new route toward the synthesis of zero‐valent SACs on BP for organic transformations.

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Section: Resultsmentioning

confidence: 99%

Zero‐Valent Palladium Single‐Atoms Catalysts Confined in Black Phosphorus for Efficient Semi‐Hydrogenation

Chen

Yam

et al. 2021

Advanced Materials

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“…In particular, we consider a charge placed equidistant from two P atoms in the top layer and two P atoms in the bottom layer, see Fig. 1(b), which is a typical configuration of intercalated transition metal atoms, such as copper or nickel [16].…”

Section: B Bilayer Bpmentioning

confidence: 99%

“…Defects can alter the material in a variety of ways, such as carrier doping, modifying carrier lifetimes and tuning the optical spectrum [13,14]. A variety of defects has been studied in few-layer BP, including intrinsic defects such as monovacancies or divacancies [15], and extrinsic defects such as substitutional tin atoms or iodine and oxygen adatoms [9,16]. If the defect donates electrons or holes to the BP, it becomes charged and induces a screened long-ranged Coulomb potential that results in the formation of bound defect states, which can be observed in scanning tunneling spectroscopy (STS) * j.lischner@imperial.ac.uk experiments.…”

Section: Introductionmentioning

confidence: 99%

Electronic Structure of Monolayer and Bilayer Black Phosphorus with Charged Defects

Aghajanian¹,

Mostofi²,

Lischner³

2021

Preprint

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We use an atomistic approach to study the electronic properties of monolayer and bilayer black phosphorus in the vicinity of a charged defect. In particular, we combine screened defect potentials obtained from first-principles linear response theory with large-scale tight-binding simulations to calculate the wavefunctions and energies of bound acceptor and donor states. As a consequence of the anisotropic band structure, the defect states in these systems form distorted hydrogenic orbitals with a different ordering than in isotropic materials. For the monolayer, we study the dependence of the binding energies of charged adsorbates on the defect height and the dielectric constant of a substrate in an experimental setup. We also compare our results to an anisotropic effective mass model and find quantitative and qualitative differences when the charged defect is close to the black phosphorus or when the screening from the substrate is weak. For the bilayer, we compare results for charged adsorbates and charged intercalants and find that intercalants induce more prominent secondary peaks in the local density of states because they interact strongly with electronic states on both layers. These new insights can be directly tested in scanning tunneling spectroscopy measurements and enable a detailed understanding of the role of Coulomb impurities in electronic devices.

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“…In addition, thermal annealing in this temperature region also facilitate the formation of extra vacancies as the anchor sites as supported by our scanning tunneling microscopy study of bulk BP ( Supplementary Figure 2-3). 27,28 Subsequently, metal organic precursors are deposited and anchored in the vacancy sites of BP flakes to form the metal-phosphorus bonding through the partial removal of organic ligands. Finally, a further ozone (O3) treatment of these samples allows for the removal of the remaining ligands of deposited metal precursors to expose the anchored single atoms on BP.…”

Section: Synthesis Of M1/bp Sacsmentioning

confidence: 99%

Zero-valent Palladium Single-Atoms Catalysts Confined in Black Phosphorus for Efficient Semi-hydrogenation

Cheng

Ou²,

Kahmeng³

et al. 2020

Preprint

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Single-atom catalysts (SACs) represent a new frontier in heterogeneous catalysis due to their remarkable catalytic properties and maximized atomic utilization. However, single atoms often bond to the support with polarized electron density and thus exhibit a high valence state, limiting their catalytic scopes in many chemical transformations. Here, we demonstrated that two-dimensional (2D) black phosphorus (BP) act as giant phosphorus (P) ligand to confine a high density of single atoms (eg, Pd1, Pt1) via atomic layer deposition. Unlike other 2D materials, BP with relatively low electronegativity and buckled structure favors the strong confinement of robust zero-valent palladium SACs in the vacancy site. Metallic Pd1/P SAC shows a highly selective semi-hydrogenation of phenylacetylene towards styrene, outperforming high-valence Pt1/P SAC, and also distinct from metallic Pd nanoparticles that facilitate the formation of fully hydrogenated products. Our DFT calculations reveal that Pd atom forms covalent-like bonding with adjacent P atoms, wherein H atoms tend to adsorb over electron-rich region for the subsequent hydrogenation. Zero-valent Pd in the confined space favors a larger energy gain for the synthesis of partially-hydrogenated product over the fully-hydrogenated one. Our work provides a new route towards the synthesis of zero-valent SACs on BP for a wide range of organic transformations.

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Structure and properties of intrinsic and extrinsic defects in black phosphorus

Abstract: The electronic and geometric structures of a range of intrinsic and extrinsic defects in black phosphorus (BP) are calculated using Density Functional Theory (DFT) and a hybrid density functional.

Cited by 47 publications

References 42 publications

Zero‐Valent Palladium Single‐Atoms Catalysts Confined in Black Phosphorus for Efficient Semi‐Hydrogenation

Zero‐Valent Palladium Single‐Atoms Catalysts Confined in Black Phosphorus for Efficient Semi‐Hydrogenation

Electronic Structure of Monolayer and Bilayer Black Phosphorus with Charged Defects

Zero-valent Palladium Single-Atoms Catalysts Confined in Black Phosphorus for Efficient Semi-hydrogenation

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