Structure Of Phosphorene Research Articles

First-principles study of sodium adsorption and diffusion over substitutionally doped phosphorene

Phosphorene, due to its remarkable semiconducting properties, prevailed as principal material of research for decades. The substitutional doping of carbon (C), silicon (Si), oxygen (O) and sulphur (S) atom was reported earlier. DFT studies are done towards the unexplored area of sodium (Na) adsorption and diffusion over these doped phosphorene structures. The effective adsorption energies for C-, Si-, O- and S- doped phosphorene are −3.19 eV, −2.63 eV, −3.12 eV and −2.39 eV respectively. The minimum value of activation energies are 0.68 eV, 0.45 eV, 1.00 eV and 0.26 eV respectively. Hence the diffusion and intercalation–deintercalation process seem to be supportive. The lattice integrity is maintained in the whole process. Good amount of charge transfer shows better conductivity supported by band structure and density of states diagrams. Based on these data, the proposed doped phosphorene configurations can be predicted suitable for further studies towards anode application in Na-ion battery.

Features of the Synthesis of Few-Layer Phosphorene Structures During Plasma Electrochemical Cleavage of Black Phosphorus

A comparative study of the emission spectra of cathode electrolysis plasma during plasma electrochemical cleavage of black phosphorus and graphite under maximally identical experimental conditions has been carried out. A significantly lower concentration of active intermediates (OH radicals and O atoms) in the electrolysis plasma during the cleavafe of black phosphorus was found compared with a graphite electrode. It is assumed that this effect is due to a significantly higher rate of interaction of these intermediates with synthesized phosphorene structures than with graphene-like particles. This is confirmed by the detection of a much higher oxygen content in the products of black phosphorus cleavage than in synthesized carbon nanoparticles.

Spin-orbit coupling effects in single-layer phosphorene

The electronic band structure of monolayer phosphorene is thoroughly studied by considering the presence of spin-orbit interaction. We employ a multiorbital Slater-Koster tight-binding approach to derive effective k·p-type Hamiltonians that describes the dominant spin-orbit coupling (SOC) effects of the Rashba and intrinsic origin at the high Γ and S high symmetry points in phosphorene. In the absence of SOC effects a minimal admixture of pz and py atomic orbitals suffices to reproduce the well-known anisotropy of highest valence and the lowest conduction bands at the Γ point, consistent with density functional theory (DFT) and k·p methods. In contrast, the inclusion of the px and s atomic orbitals are rather crucial for an adequate description of the SOC effects in phosphorene at low energies, particularly at the S point. We introduce useful analytical expressions for the Rashba and intrinsic SOC parameters in terms of the relevant Slater-Koster integrals. In addition, we report simple formulas for the interband dipole strengths, revealing the nature of the strong anisotropic behavior of its lower bands. Our findings can be useful for further studies of electronic and spin transport properties in monolayer phosphorene and its nanoribbons. Published by the American Physical Society 2024

A DFT study for improving the thermoelectric efficiency in AB bilayer phosphorene using uniaxial strain

Phosphorene is a two-dimensional (2D) semiconductor material that has attracted a lot of interest in several fields of applications. The anisotropic character of this new category of materials allows the tunability of electrical, optical, thermal, and other properties by the application of fields or forces. In the present work, using density functional theory (DFT) with the hybrid functional and Boltzmann transport equation, electronic properties, phonon dispersion and thermoelectric properties were calculated for AB bilayer phosphorene. To study the effect of the layer deformation on the thermoelectric properties of phosphorene, uniaxial tensile and compressive strain along the armchair and the zigzag direction was applied. The results revealed that AB bilayer phosphorene under a uniaxial tensile strain of 3 % along the armchair direction improve the thermoelectric properties, giving rise to a significant increase of the figure of merit to ZT = 1.24 at n-type doping. The increase of ZT upon uniaxial deformation corresponds to an increase of 110 % with respect to ZT of the unstrained AB bilayer phosphorene structure (ZT = 0.59 at 300 K).

Nanocomposite of Graphene–Phosphorene Structures with Cobalt Phosphide as an Effective Electrocatalyst for Hydrogen Evolution in Acidic Medium

Nanocomposite of Graphene–Phosphorene Structures with Cobalt Phosphide as an Effective Electrocatalyst for Hydrogen Evolution in Acidic Medium

Features of Few-Layer Phosphorene Structure Synthesis by Plasma-Assisted Electrochemical Exfoliation of Black Phosphorus

Features of Few-Layer Phosphorene Structure Synthesis by Plasma-Assisted Electrochemical Exfoliation of Black Phosphorus

Synthesis and Electrocatalytic Activity of Graphene–Phosphorene Structures Decorated with Cobalt Atoms

Synthesis and Electrocatalytic Activity of Graphene–Phosphorene Structures Decorated with Cobalt Atoms

Layer engineering in optoelectronic and photonic properties of single and few layer phosphorene using first-principles calculations.

Developing devices for optoelectronic and photonic applications-based nanomaterials has been one of the most critical challenges in the last decade. In this work, we use first-principles density functional theory combined with non-equilibrium Green's function to highlight for the first time the sensitivity of optoelectronic and photonic properties toward the exfoliation process. All the studied structures were relaxed and their relevant phonon modes confirm the high structural stability. The obtained phosphorene layers remained semiconducting with a direct band gap like the respective bulk structure with 10 layers. We also examined the effects of the thickness on the electron-hole interaction by calculating absorption energy combined with electron relaxation lifetimes. Additionally, we explore the optoelectronic properties, which can also be influenced by the exfoliation. Finally, we found that the current-voltage (I-V) characteristic shows higher sensitivity toward the bulk structure than the other 2D forms of phosphorene structures, meaning that the Schottky barrier at the interface of the bulk phosphorene is much lower than mono, and few layer phosphorene.

Rippled blue phosphorene with tunable energy band structures and negative Poisson’s ratio

Recent successes in the discovery of novel two-dimensional (2-D) phosphorene allotropes have motivated more in-depth investigations into tuning their properties through precise geometric control. This is also driven by the fact that these materials, particularly blue phosphorene, are highly prone to wrinkling. In this work, we systematically study the mechanical and electronic behaviors of a series of rippled blue phosphorene PN (N = 8, 18, 32, 50, 72, 98) using density functional theory combined with molecular dynamic simulations. A novel approach to tailor the electronic energy band structure of blue phosphorene is proposed by wrinkle engineering, transforming the native indirect bandgap into a direct bandgap, and enabling bandgap tuning by modifying the undulation magnitude ratio. Furthermore, the mechanical behaviors of rippled blue phosphorene differ significantly along the 4-8-4 and 4-4-4 directions. Notably, negative Poisson’s ratio is observed under tension along the 4-4-4 direction. This work demonstrates new techniques for geometrically regulating blue phosphorene and potentially other 2-D materials. The findings also yield valuable insights for the design of novel 2-D auxetic semiconductors with tunable electronic properties.

Differential Evolution Particle Swarm Optimization for Phase-Sensitivity Enhancement of Surface Plasmon Resonance Gas Sensor Based on MXene and Blue Phosphorene/Transition Metal Dichalcogenide Hybrid Structure.

A differential evolution particle swarm optimization (DEPSO) is presented for the design of a high-phase-sensitivity surface plasmon resonance (SPR) gas sensor. The gas sensor is based on a bilayer metal film with a hybrid structure of blue phosphorene (BlueP)/transition metal dichalcogenides (TMDCs) and MXene. Initially, a Ag-BlueP/TMDCs-Ag-MXene heterostructure is designed, and its performance is compared with that of the conventional layer-by-layer method and particle swarm optimization (PSO). The results indicate that optimizing the thickness of the layers in the gas sensor promotes phase sensitivity. Specifically, the phase sensitivity of the DEPSO is significantly higher than that of the PSO and the conventional method, while maintaining a lower reflectivity. The maximum phase sensitivity achieved is 1.866 × 106 deg/RIU with three layers of BlueP/WS2 and a monolayer of MXene. The distribution of the electric field is also illustrated, demonstrating that the optimized configuration allows for better detection of various gases. Due to its highly sensitive characteristics, the proposed design method based on the DEPSO can be applied to SPR gas sensors for environmental monitoring.

Properties of Blue Phosphorene Nanoribbon-P3HT Polymer Heterostructures: DFT First Principles Calculations

Recently, 2D phosphorus allotropes have arisen as possible candidates for technological applications among the family of the so-called Xene layered materials. In particular, the energy band structure of blue phosphorene (BP) exhibits a medium-size semiconductor gap that tends to widen in the case of using this material in the form of ribbons. BP nanoribbons have attracted recent interest for their implication in the improvement in efficiency of novel solar cells. On the other hand, compound poly (3-hexylthiophene) (P3HT) is used as the semiconducting core of organic field effect transistors owing to such useful features as high carrier mobility. Here, we theoretically investigate the electronic properties of a heterostructure combination of BP—in the form of nanoribbons—with a P3HT polymer chain on top in order to identify the features of band alignment. The work is performed using first principles calculations via DFT, employing different exchange correlation approaches for comparison: PBE, HSE06 and DFT-1/2. It is found that, under DFT-1/2, such a heterostructure has a type-II band alignment.

CoP/EEBP/N-FLGS Nanocomposite as an Efficient Electrocatalyst of Hydrogen Evolution Reaction in Alkaline Media

The search for new hydrogen evolution reaction (HER) electrocatalysts with lower cost and higher activity and stability than noble metal catalysts is essential. In this regard cobalt phosphide is considered one of the most promising nanomaterials. The present work proposes a simple and efficient method for the synthesis of a nanocomposite of graphene–phosphorene structures decorated with CoP nanoparticles 2–5 nm in size via the electrochemical exfoliation of black phosphorus carried out in the presence of nitrogen-doped few-layer graphene structures and followed by solvothermal synthesis in a Co2+-containing solution. The obtained CoP/EEBP/N-FLGS nanocomposite demonstrates high electrocatalytic activity and stability towards HER in an alkaline medium. The nanocomposite is characterized by an overpotential of 190 mV at a current density of 10 mA cm−2 as well as a small Tafel slope (78 mV dec−1). These characteristics make the CoP/EEBP/N-FLGS nanocomposite superior to most electrocatalysts based on cobalt phosphides. The results of this study could be in demand for the future design and improvement of HER electrocatalysts.

Lattice thermal conductivity calculation of phosphorene using molecular dynamics and spectral energy density

The anisotropic structure of black phosphorene makes it potentially a unique material with special anisotropic properties. Its applications and special properties call for a study of phonon dispersion and thermal transport properties. In this case, we calculate the spectral energy density from molecular dynamics to extract the phonon relaxation times and phonon mean free paths. The phosphorene's thermal conductivity was calculated at 300 K and resulted as 13.45 W/mK and 28.97 W/mK in the armchair and zigzag directions respectively which show a clear anisotropy in different directions because of the anisotropic structure of phosphorene. ZA mode phonons have a lower role in conductivity in comparison with graphene; LA phonons in the zigzag direction have a very important role and in the armchair direction both LA and TA mode phonons have higher values. In optical branches, the B1g phonons have an important role in both zigzag and armchair directions.

Nonlinear Hall effect in monolayer phosphorene with broken inversion symmetry

Nonlinear Hall effect (NLHE), a new member of the family of Hall effects, in monolayer phosphorene is investigated. We find that phosphorene exhibits pronounced NLHE, arising from the dipole moment of the Berry curvature induced by the proximity effect that breaks the inversion symmetry of the system. Remarkably, the nonlinear Hall response exhibits central minimum with a width on the order of the band gap, followed by two resonance-like peaks. Interestingly, each resonance peak of the Hall response shifts in the negative region of the chemical potential which is consistent with the shift of valence and conduction bands in the energy spectrum of monolayer phosphorene. It is observed that the two peaks are asymmetric, originated from anisotropy in the band structure of phosphorene. It is shown that the NLHE is very sensitive to the band gap and temperature of the system. Moreover, we find that a phase transition occurs in the nonlinear Hall response and nonlinear spin Hall conductivity of the system under the influence of spin–orbit interaction, tuned by the strength of interaction and band gap induced in the energy spectrum of monolayer phosphorene with broken inversion symmetry.

Kubo conductivity in phosphorene

Electrical conductivity in phosphorene is investigated within the linear response theory. We find that phosphorene shows signatures of asymmetry in its transport properties, inherited from the anisotropic band structure of that system. It is shown that the Dirac fermions in phosphorene exhibit enhanced electrical conductivity around the edges of conduction and valence bands, where the conductivity peak corresponding to the conduction band is larger than the one associated with the valence band, hallmark of anisotropic band structure of phosphorene. The separation between the two conductivity peaks is on the order of the band gap. In addition, the electrical conductivity shifts in the negative region of the chemical potential, reflecting anisotropy in the energy spectrum inherited from the lack of chiral symmetry in the Hamiltonian of the system. We also find that the electrical conductivity strongly depends on temperature of the system. Interestingly, the separation between the conductivity peaks can be tuned by an applied electric field which can vary the band gap induced by spin–orbit interaction.

Investigation of anisotropic absorption in the hybrid L-shaped graphene-black phosphorene structure

In this work, we propose a dual-band absorber in the infrared spectral region based on the periodic L-shaped graphene-black phosphorene (BP) structure. Strong and anisotropic plasmonic response were achieved by merging the benefits of isotropic plasmonic response of graphene and the anisotropic one of BP in the wavelength range of 8–22 μm for both TE and TM polarizations. According to our numerical simulations, for TE-polarization, two absorption peaks are observed in the proposed structure, approaching 98% and 99% at 8.38 μm and 15.13 μm, respectively. For TM-polarization, both absorption peaks are located at 8.52 μm and 15.54 μm, approaching 99%; a manifestation of redshift compared with TE-polarization. Furthermore, the absorption peaks can be tuned by changing the doping levels of graphene and BP layers, as well as the geometrical parameters of our absorber. This ability is well-matched for wavelength a selective sensing application that uses refractive index variations. The sensitivity of the first and the second absorption peak of our proposed device are obtained as 2.93 (3.27) μ m R I U and 6.18 (6.42) μ m R I U for TE (TM) polarization, respectively. One can conclude that this hybrid graphene-BP based tunable dual-band proposed absorber with its outstanding characterizations possesses potentials applications in sensors and reflective polarizers. graphene, black phosphorene, infrared, sensor, plasmonics. • A hybrid graphene-phosphorene structure has been designed as a dual-band perfect absorber. • Isotropic and anisotropic optical properties of, respectively, graphene and phosphorene has been combined. • The absorption peaks can be tuned by doping levels e geometrical parameters. • The device is well-matched for wavelength selective sensing applications for refractive index.

Mechanical and thermal properties of phosphorene under shear deformation

Phosphorene, a new two-dimensional material beyond graphene, has received increasing attention in recent years owing to its superior physical properties of significant utility. Herein we carry out molecular dynamics simulations to systematically study the mechanical and thermal properties of phosphorene under shear loadings. It is found that the shear modulus of phosphorene is about 22 GPa in both the armchair direction and zigzag direction. The fracture strength and ultimate strain of phosphorene can be significantly reduced owing to stronger thermal vibrations of atoms at a higher temperature. The thermal conductivity of pristine phosphorene at room temperature is obtained, specifically, it is 18.57 W·m<sup>–1</sup>·K<sup>–1</sup> along the armchair direction and 52.52 W·m<sup>–1</sup>·K<sup>–1</sup> in the zigzag direction. When either an armchair- or a zigzag-oriented shear strain is applied, the armchair-oriented thermal conductivity decreases monotonically with the strain increasing. Whereas the zigzag-oriented thermal conductivity exhibits a non-monotonic behavior. The strain-induced redshift occurs in the high-frequency phonons of out-of-plane flexural modes in the phonon density of states of the sheared phosphorene. In addition, the buckled structure of phosphorene will lead the deformation characteristics under the shear strain differ from those of the planar structure such as graphene, which has a significant influence on the lattice anharmonicity and phonon scattering. It is believed that the interplay between the shift of phonon density of states and the change of phonon scattering channels results in the unique thermal transport behavior of phosphorene under shear deformation. The findings provide an insight into the understanding of the mechanical and thermal properties of phosphorene, and have significance for the future applications in phosphorene-based novel devices.

Plasma Electrochemical Synthesis of Graphene-Phosphorene Composite and Its Catalytic Activity towards Hydrogen Evolution Reaction

For the first time, graphene-phosphorene structures were synthesized using the plasma-assisted electrochemical method. The catalytic activity of the composite obtained in the electrolytic plasma mode and its mixtures with few-layer graphene structures toward the hydrogen evolution reaction was studied. A substantial increase in the catalytic activity of the phosphorene structures towards the hydrogen evolution reaction was realized by mixing them with few-layer graphene structures. The catalyst demonstrates excellent activity towards the hydrogen evolution reaction in alkaline media with a low overpotential of 940 mV at a current density of 10 mA·cm−2 and a small Tafel slope of 130 mV dec−1.

Ultra-Narrow Phosphorene Nanoribbons Produced by Facile Electrochemical Process.

Phosphorene nanoribbons (PNRs) have inspired strong research interests to explore their exciting properties that are associated with the unique two-dimensional (2D) structure of phosphorene as well as the additional quantum confinement of the nanoribbon morphology, providing new materials strategy for electronic and optoelectronic applications. Despite several important properties of PNRs, the production of these structures with narrow widths is still a great challenge. Here, a facile and straightforward approach to synthesize PNRs via an electrochemical process that utilize the anisotropic Na+ diffusion barrier in black phosphorus (BP) along the [001] zigzag direction against the [100] armchair direction, is reported. The produced PNRs display widths of good uniformity (10.3 ± 3.8nm) observed by high-resolution transmission electron microscopy, and the suppressed B2g vibrational mode from Raman spectroscopy results. More interestingly, when used in field-effect transistors, synthesized bundles exhibit the n-type behavior, which is dramatically different from bulk BP flakes which are p-type. This work provides insights into a new synthesis approach of PNRs with confined widths, paving the way toward the development of phosphorene and other highly anisotropic nanoribbon materials for high-quality electronic applications.

Realization of unpinned two-dimensional dirac states in antimony atomic layers

Two-dimensional (2D) Dirac states with linear dispersion have been observed in graphene and on the surface of topological insulators. 2D Dirac states discovered so far are exclusively pinned at high-symmetry points of the Brillouin zone, for example, surface Dirac states at overline{{{Gamma }}} in topological insulators Bi2Se(Te)3 and Dirac cones at K and K^{prime} points in graphene. The low-energy dispersion of those Dirac states are isotropic due to the constraints of crystal symmetries. In this work, we report the observation of novel 2D Dirac states in antimony atomic layers with phosphorene structure. The Dirac states in the antimony films are located at generic momentum points. This unpinned nature enables versatile ways such as lattice strains to control the locations of the Dirac points in momentum space. In addition, dispersions around the unpinned Dirac points are highly anisotropic due to the reduced symmetry of generic momentum points. The exotic properties of unpinned Dirac states make antimony atomic layers a new type of 2D Dirac semimetals that are distinct from graphene.