Violet Phosphorus Research Articles

Violet phosphorus quantum dots

Violet phosphorus quantum dots have been produced for the first time, which are effective fluorescent probes to selectively detect Cu2+. The morphology, microstructure and fluorescence properties have been tuned using synthesis parameters.

Large-Scale Synthesis of Violet Phosphorus Nanosheets with Superior Air-Water Stability

Large-Scale Synthesis of Violet Phosphorus Nanosheets with Superior Air-Water Stability

2D Violet phosphorene with highly anisotropic mobility and its vdW heterojunction design for device applications.

Recently, the crystal structure of violet phosphorus and its monolayer violet phosphorene (VP) have been reconfirmed experimentally, and they were verified to be more thermally stable than their allotrope, black phosphorus. Here, we calculated the carrier mobility of monolayer VP using density functional theory. It is found that the carrier mobility is highly anisotropic and the hole mobility reaches 9.86 × 103 cm2 V-1 s-1 in the a-direction, endowing the potential application of VP in p-type semiconductor channel materials. Moreover, the Schottky barrier of the graphene/VP heterojunction turns into an ohmic contact when the electric field strength is >2 V nm-1. Therefore, VP and graphene/VP heterojunctions have potential prospects in electronic devices.

Impurity‐Induced Robust Trionic Effect in Layered Violet Phosphorus

AbstractTrionic effect is a vital excitonic physical phenomenon, which intensively affects the optical and optoelectronic properties of 2D materials. Violet phosphorus (VP) is another allotrope of elemental phosphorus with robust photoluminescence (PL) emission in the visible range. So far, experimental investigations of the excitonic behavior in VP are quite scarce. Herein, the evolution of the PL mechanism in synthesized VP crystals against the Ar+ plasma exposure is investigated with emphasis on a conversion from trion to exciton emission. The estimated trion binding energy of VP is ≈109 meV, relatively larger than common layered materials. By analyzing the chemical states and the atomic structures, the conversion mechanism is proposed as follows. The Ar+ plasma treatment reduces the stannous SnIP impurities’ population, which are incorporated into the VP lattices and serve as the n‐type dopants leading to the trion formation. Besides, various surface defects (POx) can promote the trion‐to‐exciton conversion by withdrawing electrons from VP in the process and act as hole‐trap centers to enhance the photodetection of VP phototransistors. This work reveals that the layered VP crystal can provide an ideal platform to study the excitonic physics and future trionic devices at the 2D limit.

Atomic-Scale Friction of Black and Violet Phosphorus Crystals: Implications for Phosphorus-Based Devices and Lubricants

Atomic-Scale Friction of Black and Violet Phosphorus Crystals: Implications for Phosphorus-Based Devices and Lubricants

Liquid‐phase exfoliation of violet phosphorus for electronic applications

AbstractLarge‐scale production of two‐dimensional (2D) materials still is a crucial point toward its practical applications. Violet phosphorus (VP) with a wide bandgap accelerates and broadens the potential applications of elemental phosphorus in optoelectronics. Here, we demonstrate the scalable production of solution‐processable violet phosphorus flakes stably dispersed in several solvents. The exfoliated VP flakes exhibit thickness‐dependent visible photoluminescence characteristics, which covers the shortcoming of black phosphorus. Meanwhile, the VP‐based field‐effect transistor reveals relatively competitive electrical properties to other liquid‐phase exfoliated 2D materials. Our study paves the way for a wide range of applications of optical devices, energy storage, catalysis, and sodium batteries based on large‐scale VP flakes.

A Cysteine-Mediated Synthesis of Red Phosphorus Nanosheets.

Among phosphorus-based nanomaterials, layered black phosphorus and violet phosphorus have been actively explored in the past decade. However, methods for the synthesis of red phosphorus nanosheets (RPNSs) is lacking, even though red phosphorus (RP) is commercially available at low cost and has excellent chemical stability at room temperature. We report an efficient strategy for fabrication of RPNSs and doped RPNSs using cysteine as a reducing reagent. Data from in vitro and in vivo studies suggested that RPNSs can trigger production of reactive oxygen species, DNA damage, and subsequent autophagy-mediated cell death in a shape-dependent manner. Our findings provide a method for construction of layered RP nanomaterials and they present a unique mechanism for the application of phosphorus-based materials in nanomedicines.

A Cysteine‐Mediated Synthesis of Red Phosphorus Nanosheets

AbstractAmong phosphorus‐based nanomaterials, layered black phosphorus and violet phosphorus have been actively explored in the past decade. However, methods for the synthesis of red phosphorus nanosheets (RPNSs) is lacking, even though red phosphorus (RP) is commercially available at low cost and has excellent chemical stability at room temperature. We report an efficient strategy for fabrication of RPNSs and doped RPNSs using cysteine as a reducing reagent. Data from in vitro and in vivo studies suggested that RPNSs can trigger production of reactive oxygen species, DNA damage, and subsequent autophagy‐mediated cell death in a shape‐dependent manner. Our findings provide a method for construction of layered RP nanomaterials and they present a unique mechanism for the application of phosphorus‐based materials in nanomedicines.

Violet phosphorus surface chemical degradation in comparison to black phosphorus

Bulk growth methods have made it possible to synthesize several allotropes of phosphorus such as black, white, red, and violet phosphorus. However, unlike exfoliated black phosphorus (BP), which has been extensively studied, much of the optoelectronic properties and stability of the other allotropes have yet to be comprehensively investigated. Here, we study the chemical degradation of exfoliated violet phosphorus (VP) in comparison to BP under ambient conditions using nanoscale infrared spectroscopy and imaging. We identify oxidized phosphorus species that result from chemical reaction processes on the surfaces of these phosphorus allotropes. We have found that VP exhibits a noticeably different and slower degradation process when compared to BP, establishing it as the more stable of the two allotropes. A better understanding of the stability of VP could lead to the further fundamental study of its monolayer form for potential future applications.

First-principles prediction of Hittorf's violet phosphorene as a promising candidate of anode material for Li- and Na-ion batteries

Hittorf's violet phosphorus is the most stable phosphorus allotrope with a layered structure. The corresponding Hittorf's violet phosphorene, a more stable two-dimensional semiconducting structure than black phosphorene, is a promising two-dimensional material for electronic and optoelectronic devices. In this work, the adsorption and anisotropic diffusion process of Li and Na atoms have been studied using first-principles calculations. The adsorption energies of Li and Na atoms are calculated to be 1.65 and 1.32 eV, respectively. Based on the structural nature of Hittorf's violet phosphorene, two possible diffusion paths (in-trench diffusion and inter-trench diffusion) are proposed and investigated. The results of transition state calculation indicate that in-trench diffusion of metal atom has lower barrier that inter-trench diffusion, indicating the significant anisotropic diffusion of Li and Na atom on Hittorf's violet phosphorene. Our work suggests the promising application of Hittorf's violet phosphorene in ion batteries research and development.

Phonon Properties of Bulk Violet Phosphorus Single Crystals: Temperature and Pressure Evolution

Violet phosphorus, the most stable phosphorus allotrope, has been successfully produced recently. Phonon properties of layered structures are important characteristic features to provide their stru...

A general-purpose machine-learning force field for bulk and nanostructured phosphorus

Elemental phosphorus is attracting growing interest across fundamental and applied fields of research. However, atomistic simulations of phosphorus have remained an outstanding challenge. Here, we show that a universally applicable force field for phosphorus can be created by machine learning (ML) from a suitably chosen ensemble of quantum-mechanical results. Our model is fitted to density-functional theory plus many-body dispersion (DFT + MBD) data; its accuracy is demonstrated for the exfoliation of black and violet phosphorus (yielding monolayers of “phosphorene” and “hittorfene”); its transferability is shown for the transition between the molecular and network liquid phases. An application to a phosphorene nanoribbon on an experimentally relevant length scale exemplifies the power of accurate and flexible ML-driven force fields for next-generation materials modelling. The methodology promises new insights into phosphorus as well as other structurally complex, e.g., layered solids that are relevant in diverse areas of chemistry, physics, and materials science.

High Yield Synthesis of Violet Phosphorus Crystals

Violet phosphorus is the most stable phosphorus allotrope with a layered structure. The corresponding violet phosphorene, a more stable two-dimensional semiconducting structure than black phosphorene, is a promising two-dimensional material for electronic and optoelectronic devices. The synthesis of violet phosphorus is the key factor to its experimental research. However, no clear evidence has been reported for the synthesis of violet phosphorus since its first proposal in 1865. The violet phosphorus was even debated to be a metastable intermediate phase. Until recently, the violet phosphorus crystals have just been successfully produced and exfoliated to give violet phosphorene. High yield synthesis of highly crystalline and pure violet phosphorus is crucial for the further exploration of violet phosphorus and phosphorene. In this work, highly crystalline and pure violet phosphorus crystals have been produced with a yield as high as 80%. The vapor transport, nucleation, crystal growth conditions, and synthesis mechanism have been studied to obtain violet phosphorus instead of black phosphorus. The mixture of transport agents and amorphous red phosphorus was heated to 600 °C to form P–Sn–I vapor and transported to the cooler zone (580 °C). The phosphorus was separated out from the P–Sn–I composites after cooling down to 530 °C to form violet phosphorus nuclei. The nucleation time and further cooling time correspond to the amount and crystallinity of violet phosphorus crystals. The precipitation has been demonstrated to be SnI2 crystals with a space group of C2/m (12) after the growth of violet phosphorus crystals. The synthesis of highly crystalline and pure violet phosphorus with high yield provides the application possibility of violet phosphorus and phosphorene in mechanic, electronic, optoelectronic, catalysts, and medical fields.

Frontispiece: Structure and Properties of Violet Phosphorus and Its Phosphorene Exfoliation

Frontispiece: Structure and Properties of Violet Phosphorus and Its Phosphorene Exfoliation

Frontispiz: Structure and Properties of Violet Phosphorus and Its Phosphorene Exfoliation

Frontispiz: Structure and Properties of Violet Phosphorus and Its Phosphorene Exfoliation

Structure and Properties of Violet Phosphorus and Its Phosphorene Exfoliation

AbstractBlack phosphorene has attracted much attention as a semiconducting two‐dimensional material. Violet phosphorus is another layered semiconducting phosphorus allotrope with unique electronic and optoelectronic properties. However, no confirmed violet crystals or reliable lattice structure of violet phosphorus had been obtained. Now, violet phosphorus single crystals were produced and the lattice structure has been obtained by single‐crystal x‐ray diffraction to be monoclinic with space group of P2/n (13) (a=9.210, b=9.128, c=21.893 Å, β=97.776°). The lattice structure obtained was confirmed to be reliable and stable. The optical band gap of violet phosphorus is around 1.7 eV, which is slightly larger than the calculated value. The thermal decomposition temperature was 52 °C higher than its black phosphorus counterpart, which was assumed to be the most stable form. Violet phosphorene was easily obtained by both mechanical and solution exfoliation under ambient conditions.

Structure and Properties of Violet Phosphorus and Its Phosphorene Exfoliation.

Black phosphorene has attracted much attention as a semiconducting two-dimensional material. Violet phosphorus is another layered semiconducting phosphorus allotrope with unique electronic and optoelectronic properties. However, no confirmed violet crystals or reliable lattice structure of violet phosphorus had been obtained. Now, violet phosphorus single crystals were produced and the lattice structure has been obtained by single-crystal x-ray diffraction to be monoclinic with space group of P2/n (13) (a=9.210, b=9.128, c=21.893 Å, β=97.776°). The lattice structure obtained was confirmed to be reliable and stable. The optical band gap of violet phosphorus is around 1.7 eV, which is slightly larger than the calculated value. The thermal decomposition temperature was 52 °C higher than its black phosphorus counterpart, which was assumed to be the most stable form. Violet phosphorene was easily obtained by both mechanical and solution exfoliation under ambient conditions.

The structure and electronic properties of crimson phosphorus

Semiconducting layered phosphorus allotropes, such as black and violet phosphorus, are attracting more and more attention due to their predicted high hole mobilities (up to 1000 cm2 V−2 s−1). Violet phosphorus is assumed to be the intermediate structure between amorphous red phosphorus and black phosphorus. Is there any other reasonable and stable allotrope between them? An unexplored layered phosphorus allotrope, crimson phosphorus, has been predicted by the ab initio method. The crystal structure, elastic moduli, band structure, and charge carrier mobility of crimson phosphorus have been investigated. A higher symmetry with similar energetic stability and a narrower bandgap compared to those of violet phosphorus has been obtained by crimson phosphorus. The hole mobilities of crimson phosphorus have been calculated to be 5383 (μx) and 1072 (μy) cm2 V−1 s−1, which are much higher than those of violet phosphorus (μx: 91 cm2 V−1 s−1 and μy: 27 cm2 V−1 s−1) and black phosphorus (μx: 3525 cm2 V−1 s−1 and μy: 9 cm2 V−1 s−1). Additionally, much higher hole mobility anisotropy has been demonstrated by crimson phosphorus. Lower electron mobility compared with those of black and violet ones has been obtained by crimson phosphorus. The unique electronic properties of crimson phosphorus provide promising 2D materials for desired devices.

Front Cover: Bis‐[3]Ferrocenophanes with Central >E−E’< Bonds (E, E’=P, SiH): Preparation, Properties, and Thermal Activation (ChemistryOpen 10/2019)

The Front Cover visualizes the thermally induced homolytic cleavage of the central P-P bond in a phosphorus–rich bis-ferrocenophane furnishing P-centered radicals. The bond fission process and conformational dynamics in this compound as well as isolobal analogues obtained by formal replacement of individual P-atoms by nitrogen atoms or SiH fragments is elucidated from analysis of their variable temperature NMR and EPR spectra and simulated by DFT calculations. The central P6 unit in the title compound is a structural analog of the connecting unit in Hittorf's violet phosphorus, which links the orthogonally arranged tubular entities. More information can be found in the Full Paper by S. Isenberg et al. on page 1235 in Issue 10, 2019 (DOI: 10.1002/open.201900182).

Bis-[3]Ferrocenophanes with Central >E-E'< Bonds (E, E'=P, SiH): Preparation, Properties, and Thermal Activation.

Invited for this month's cover picture are the groups of Professors Rudolf Pietschnig at the University of Kassel, Professor Dietrich Gudat at the University of Stuttgart and Professor László Nyulászi at the Budapest University of Technology and Economics. The cover picture shows the thermally induced homolytic cleavage of the central P-P bond in a phosphorus-rich bis-ferrocenophane furnishing P-centered radicals (as evidenced by the computed spin-density highlighted in blue). The central P6 unit in the title compound is a structural analog of the connecting unit in Hittorf's violet phosphorus, which links the orthogonally arranged tubular entities. A portrait of the German physicist Johann Wilhelm Hittorf is included. Read the full text of their Full Paper at 10.1002/open.201900182.