Novel bismuthene nanotubes to detect NH3, NO2 and PH3 gas molecules – A first-principles insight

The elemental 2D materials beyond graphene potentially used as hazardous gas sensors for environmental protection

The intrinsic and electronic properties of elemental two-dimensional (2D) materials beyond graphene are first introduced in this review. Then the studies concerning the application of gas sensing using these 2D materials are comprehensively reviewed. On the whole, the carbon-, nitrogen-, and sulfur-based gases could be effectively detected by using most of them. For the sensing of organic vapors, the borophene, phosphorene, and arsenene may perform it well. Moreover, the G-series nerve agents might be efficiently monitored by the bismuthene. So far, there is still challenge on the material preparation due to the instability of these 2D materials under atmosphere. The synthesis or growth of materials integrated with the technique of surface protection should be associated with the device fabrication to establish a complete process for particular application. This review provides a complete and methodical guideline for scientists to further research and develop the hazardous gas sensors of these 2D materials in order to achieve the purpose of environmental protection.

Chemistry, Functionalization, and Applications of Recent Monoelemental Two-Dimensional Materials and Their Heterostructures

The past decades have witnessed a rapid expansion in investigations of two-dimensional (2D) monoelemental materials (Xenes), which are promising materials in various fields, including applications in optoelectronic devices, biomedicine, catalysis, and energy storage. Apart from graphene and phosphorene, recently emerging 2D Xenes, specifically graphdiyne, borophene, arsenene, antimonene, bismuthene, and tellurene, have attracted considerable interest due to their unique optical, electrical, and catalytic properties, endowing them a broader range of intriguing applications. In this review, the structures and properties of these emerging Xenes are summarized based on theoretical and experimental results. The synthetic approaches for their fabrication, mainly bottom-up and top-down, are presented. Surface modification strategies are also shown. The wide applications of these emerging Xenes in nonlinear optical devices, optoelectronics, catalysis, biomedicine, and energy application are further discussed. Finally, this review concludes with an assessment of the current status, a description of existing scientific and application challenges, and a discussion of possible directions to advance this fertile field.

Emerging pnictogen-based 2D semiconductors: sensing and electronic devices

Pnictogens are an intensively studied group of monoelemental two-dimensional materials. This group of elements consists of phosphorus, arsenic, antimony, and bismuth. In this group, the elements adopt two different layered structural allotropes, orthorhombic structure with true van der Waals layered interactions and rhombohedral structure, where covalent interactions between layers are also present. The orthorhombic structure is well known for phosphorus and arsenic, and the rhombohedral structure is the most thermodynamically stable allotropic modification of arsenic, antimony, and bismuth. Due to the electronic structure of pnictogen layers and their semiconducting character, these materials have huge application potential for electronic devices such as transistors and sensors including photosensitive devices as well as gas and electrochemical sensors. While photodetection and gas sensing applications are often related to lithography processed materials, chemical sensing proceeds in a liquid environment (either aqueous or non-aqueous) and can be influenced by surface oxidation of these materials. In this review, we explore the current state of pnictogen applications in sensing and electronic devices including transistors, photodetectors, gas sensors, and chemical/electrochemical sensors.