2D group-VA Research Articles

Recent Progress in Synthesis and Photonic Applications of Two-Dimensional Bismuthene

The emergence of phosphorene has generated significant interest in 2D group VA nanomaterials. Among this group, bismuthene exhibits layer-dependent direct bandgaps, high carrier mobility, and topological insulator properties because of its unique structure and ultrathin nature, distinguishing it as a promising candidate for photonic applications. Particularly, its outstanding stability in air makes bismuthene more advantageous than phosphorene for practical applications. Here, we provide a comprehensive review of recent advances regarding 2D bismuth by focusing on the aspects of methods of synthesis and photonic applications. First, the structure and fundamental properties of bismuthene are described, referring to its crystallinity and band structures, as well as to its nonlinear optical properties. Subsequently, the common synthesis methods for 2D bismuth are summarized, including both top-down and bottom-up approaches. Then, potential photonic applications based on 2D bismuth, involving nonlinear photonic devices, photocatalyst, and photodetectors, are illustrated. The performance, mechanisms, and features of the devices are discussed. Finally, the review is summarized and some challenges and future outlooks in this field are addressed.

2D Layers of Group VA Semiconductors: Fundamental Properties and Potential Applications.

Members of the 2D group VA semiconductors (phosphorene, arsenene, antimonene, and bismuthine) present a new class of 2D materials, which are recently gaining a lot of research interest. These materials possess layered morphology, tunable direct bandgap, high charge carrier mobility, high stability, unique in-plane anisotropy, and negative Poisson's ratio. They prepare the ground for novel and multifunctional applications in electronics, optoelectronics, and batteries. The most recent analytical and empirical developments in the fundamental characteristics, fabrication techniques, and potential implementation of 2D group VA materials in this review, along with presenting insights and concerns for the field's future are analyzed.

Stability and passivation of 2D group VA elemental materials: black phosphorus and beyond

Since the successful isolation of graphene in 2004, two-dimensional (2D) materials have become one of the focuses in material science owing to their extraordinary physical and chemical properties. In particular, 2D group VA elemental materials exhibit fascinating thickness-dependent band structures. Unfortunately, the well-known instability issue hinders their fundamental researches and practical applications. In this review, we first discuss the degradation mechanism of black phosphorus (BP), a most studied group VA material. Next, we summarize the methods to enhance BP stability with the focus of multifunctional passivation. Finally, we briefly discuss the protection strategies of other emerging group VA materials in recent years. This review provides insight for the degradation mechanism and protecting strategy for 2D group VA elements materials, which will promote their potential applications in electronics, optoelectronics, and biomedicine.

Soft-template assisted synthesis of hexagonal antimonene and bismuthene in colloidal solutions.

Monoelemental two-dimensional (2D) group-VA materials have received increasing interest due to their great potential in optoelectronic applications. Despite numerous efforts have been made for their syntheses, the development of effective and better controllable synthetic approaches for the preparation of monoelemental 2D group-VA materials is still in its infancy. In this work, we report a soft-template approach for the synthesis of multilayered antimonene and bismuthene nanosheets in colloidal solutions. We show that the prepared antimonene and bismuthene nanosheets possess a well-defined rhombohedral crystal structure with impressive stability. We elucidate a formation pathway for the 2D nanosheets with small-angle X-ray diffraction (XRD) analysis. We demonstrate that SbCl3 dissolves in alkyl phosphonic acids to form a lamellar structure initially, which is apt for the formation of the final 2D morphology. The present study introduces a general route to synthesizing monoelemental 2D group-VA materials in colloidal solutions and gives a deeper insight into their growth mechanism.

Band engineering realized by chemical combination in 2D group VA–VA materials

Theoretical motivation for chemical combination in 2D group VA–VA materials and their novel electronic structures.

2D group-VA fluorinated antimonene: synthesis and saturable absorption.

A new derivative of antimonene named fluorinated antimonene was synthesized using the method of ionic liquid-assisted electrochemical exfoliation and synchronous fluorination. Passive Q-switched pulses were produced from a Nd:LuAG laser with fluorinated antimonene, having a pulse width of 326.7 ns and a repetition rate of 733.1 kHz demonstrating its potential application as a saturable absorber. Density functional theory calculations revealed that compared with pure antimonene with an indirect bandgap, fluorinated antimonene exhibits a direct bandgap modulated by the fluorination degree showing that fluorinated antimonene would be applied as optical devices beyond its application as a saturable absorber.

Two-dimensional group-VA porous crystals: Diverse electronic structures and photocatalytic properties

The two-dimensional materials (2D) have been widely investigated due to their unique properties. In this paper, based on DFT calculations, a family of novel 2D group-VA porous crystals have been explored, which are named as T-VA (VA = P, As, Sb, and Bi) due to the tetragonal lattice. Their thermal stability has been carefully confirmed due to careful phonon calculations. These 2D materials possess high specific surface area due to big intrinsic porous crystals, making them good candidates for catalysts. More importantly, they are semiconductors with wide band gap range of 0.94–2.78 eV (HSE06 level) and also exhibit considerable absorption index on both visible and infrared regions of solar energy as well as suitable band alignments for photocatalytic water-splitting. Such results reveal a group of novel 2D materials based on group-VA elements which are expected to be fabricated and utilized as nanoelectronics and photocatalysts.

Recent progress in 2D group-VA semiconductors: from theory to experiment.

Phosphorene, an emerging two-dimensional material, has received considerable attention due to its layer-controlled direct bandgap, high carrier mobility, negative Poisson's ratio and unique in-plane anisotropy. As cousins of phosphorene, 2D group-VA arsenene, antimonene and bismuthene have also garnered tremendous interest due to their intriguing structures and fascinating electronic properties. 2D group-VA family members are opening up brand-new opportunities for their multifunctional applications encompassing electronics, optoelectronics, topological spintronics, thermoelectrics, sensors, Li- or Na-batteries. In this review, we extensively explore the latest theoretical and experimental progress made in the fundamental properties, fabrications and applications of 2D group-VA materials, and offer perspectives and challenges for the future of this emerging field.

Antimonene Oxides: Emerging Tunable Direct Bandgap Semiconductor and Novel Topological Insulator.

Highly stable antimonene, as the cousin of phosphorene from group-VA, has opened up exciting realms in the two-dimensional (2D) materials family. However, pristine antimonene is an indirect band gap semiconductor, which greatly restricts its applications for optoelectronics devices. Identifying suitable materials, both responsive to incident photons and efficient for carrier transfer, is urgently needed for ultrathin devices. Herein, by means of first-principles computations we found that it is rather feasible to realize a new class of 2D materials with a direct bandgap and high carrier mobility, namely antimonene oxides with different content of oxygen. Moreover, these tunable direct bandgaps cover a wide range from 0 to 2.28 eV, which are crucial for solar cell and photodetector applications. Especially, the antimonene oxide (18Sb-18O) is a 2D topological insulator with a sizable global bandgap of 177 meV, which has a nontrivial Z2 topological invariant in the bulk and the topological states on the edge. Our findings not only introduce new vitality into 2D group-VA materials family and enrich available candidate materials in this field but also highlight the potential of these 2D semiconductors as appealing ultrathin materials for future flexible electronics and optoelectronics devices.