Density functional theory study on gas-sensing property of (SnO2)n (n = 1–3) modified MoTe2 towards chlorine, ammonia, and sulphur dioxide upon diesel-driven vehicle

Chlorine (Cl2), ammonia (NH3), and sulphur dioxide (SO2) are three typical toxic gases of tank-vehicle transportation. it is necessary to conduct online detection of these gases to ensure transportation safety and exhaust emission monitoring. In this study, tin dioxide (SnO2)n (n = 1–3) modified molybdenum (IV) telluride (MoTe2) monolayer were selected to explore its adsorption characteristics towards Cl2, NH3, and SO2 gases. All calculations are based on density function theory, geometric structure, charge transfer, adsorption energy, the density of states, and molecular orbitals were taken into account to compare and analyze the adsorption performance of the gas-sensing material before and after surface modification. The results show that these three gases are physically adsorbed on the intrinsic material. The modified (SnO2)n (n = 1–3) are all stably bound to the MoTe2 surface. For both Cl2 and NH3, the adsorption energies are in order of SnO2-MoTe2 > (SnO2)2-MoTe2 > (SnO2)3-MoTe2. And the adsorption energies for SO2 can be ranked as (SnO2)3-MoTe2 > SnO2-MoTe2 > (SnO2)2-MoTe2. The significant changes in electrical conductivity indicate the modified MoTe2 system consistently showed excellent sensitivity to the three gases. Therefore, the (SnO2)n-modified MoTe2 system is expected to be a candidate gas-sensing material for Cl2, NH3, and SO2, opening up a new perspective on MoTe2 in the field of gas detection

Improving hard metal implant and soft tissue integration by modulating the “inflammatory-fibrous complex” response

Soft tissue integration is one major difficulty in the wide applications of metal materials in soft tissue-related areas. The inevitable inflammatory response and subsequent fibrous reaction toward the metal implant is one key response for metal implant-soft tissue integration. It is of great importance to modulate this inflammatory-fibrous response, which is mainly mediated by the multidirectional interaction between fibroblasts and macrophages. In this study, macrophages are induced to generate M1 and M2 macrophage immune microenvironments. Their cytokine profiles have been proven to have potentially multi-regulatory effects on fibroblasts. The multi-reparative effects of soft tissue cells (human gingival fibroblasts) cultured on metal material (titanium alloy disks) in M1 and M2 immune microenvironments are then dissected. Fibroblasts in the M1 immune microenvironment tend to aggravate the inflammatory response in a pro-inflammatory positive feedback loop, while M2 immune microenvironment enhances multiple functions of fibroblasts in soft tissue integration, including soft tissue regeneration, cell adhesion on materials, and contraction to immobilize soft tissue. Enlighted by the close interaction between macrophages and fibroblasts, we propose the concept of an “inflammatory-fibrous complex” to disclose possible methods of precisely and effectively modulating inflammatory and fibrous responses, thus advancing the development of metal soft tissue materials

Evolution of the Valley Position in Bulk Transition-Metal Chalcogenides and Their Monolayer Limit.

Layered transition metal chalcogenides with large spin orbit coupling have recently sparked much interest due to their potential applications for electronic, optoelectronic, spintronics, and valleytronics. However, most current understanding of the electronic structure near band valleys in momentum space is based on either theoretical investigations or optical measurements, leaving the detailed band structure elusive. For example, the exact position of the conduction band valley of bulk MoS2 remains controversial. Here, using angle-resolved photoemission spectroscopy with submicron spatial resolution (micro-ARPES), we systematically imaged the conduction/valence band structure evolution across representative chalcogenides MoS2, WS2, and WSe2, as well as the thickness dependent electronic structure from bulk to the monolayer limit. These results establish a solid basis to understand the underlying valley physics of these materials, and also provide a link between chalcogenide electronic band structure and their physical properties for potential valleytronics applications

Evolution of the Valley Position in Bulk Transition-Metal Chalcogenides and Their Monolayer Limit

Layered transition metal chalcogenides with large spin orbit coupling have recently sparked much interest due to their potential applications for electronic, optoelectronic, spintronics, and valleytronics. However, most current understanding of the electronic structure near band valleys in momentum space is based on either theoretical investigations or optical measurements, leaving the detailed band structure elusive. For example, the exact position of the conduction band valley of bulk MoS2 remains controversial. Here, using angle-resolved photoemission spectroscopy with submicron spatial resolution (micro-ARPES), we systematically imaged the conduction/valence band structure evolution across representative chalcogenides MoS2, WS2, and WSe2, as well as the thickness dependent electronic structure from bulk to the monolayer limit. These results establish a solid basis to understand the underlying valley physics of these materials, and also provide a link between chalcogenide electronic band structure and their physical properties for potential valleytronics applications