Annealing-enhanced interlayer coupling interaction in GaS/MoS2 heterojunctions

Fabrication of large-area atomically thin transition metal dichalcogenides is of critical importance for the preparation of new heterojunction-based devices.In this paper, we report the fabrication and optical investigation of large-scale chemical vapor deposition(CVD)-grown monolayer MoS2 and exfoliated few-layer GaS heterojunctions.As revealed by photoluminescence(PL) characterization, the as-fabricated heterojunctions demonstrated edge interaction between the two layers.The heterojunction was sensitive to annealing and showed increased interaction upon annealing at 300℃ under vacuum conditions, which led to changes in both the emission peak position and intensity resulting from the strong coupling interaction between the two layers.Low-temperature PL measurements further confirmed the strong coupling interaction.In addition, defect-related GaS luminescence was observed in our few-layer GaS, and the PL mapping provided evidence of edge interaction coupling between the two layers.These findings are interesting and provide the basis for creating new material systems with rich functionalities and novel physical effects.

电流退火Fe76Si7.6B9.5P5C1.9合金薄带的纵向巨磁阻抗效应

有效地调控非晶软磁材料的巨磁阻抗,能使其应用的领域更加广泛。本文研究了在大气环境下电流退火过程中Fe76Si7.6B9.5P5C1.9合金薄带纵向巨磁阻抗的变化规律,发现氧化可以调控样品的巨磁阻抗性能。通过10 min退火,样品磁性能得到明显改善,灵敏度大幅度提高;1 h退火,样品的GMI表现出良好的线性关系。

Electricity resonance-induced phase transition of water confined in nanochannels

The phase transition of water molecules in nanochannels under varying external electric fields is studied by molecular dynamics simulations.It is found that the phase transition of water molecules in nanochannels occurs by changing the frequency of the varying electric field.Water molecules maintain the ice phase when the frequency of the varying electric field is less than 16 THz or greater than 30 THz,and they completely melt when the frequency of the varying electric field is 24 THz.This phenomenon is attributed to the breaking of hydrogen bonds when the frequency of the varying electric field is close to their inherent resonant frequency.Moreover,the study demonstrates that the critical frequency varies with the confinement situation.The new mechanism of regulating the phase transition of water molecules in nanochannels revealed in this study provides a perspective for further understanding of the phase transition of water molecules in nanochannels,and has great application potential in preventing icing and deicing.

Interface water-induced hydrophobic carbon chain unfolding in water

The folding and unfolding of the carbon chain,which is the basic constitutional unit of polymers,are important to the performance of the material.However,it is difficult to regulate conformational transition of the carbon chain,especially in an aqueous environment.In this paper,we propose a strategy to regulate the conformational transition of the carbon chain in water based on the all-atom molecular dynamics simulations.It is shown that the unfolded carbon chain will spontaneously collapse into the folded state,while the folded carbon chain will unfold with an external electric field.The regulation ability of the electric field is attributed to the electric field-induced redistribution of interface water molecules near the carbon chain.The demonstrated method of regulating conformational transition of the carbon chain in water in this study provides an insight into regulating hydrophobic molecules in water,and has great potential in drug molecule design and new polymer material development.

Reduced graphene oxide-based calcium alginate hydrogel as highly efficient solar steam generation membrane for desalination

Solar-driven evaporation has been considered as one of the potentialmethods for desalination and sewage treatment.However,optical concentrators andcomplex multi-component systems are essential in advanced technologies,resulting inlow efficiency and high cost.Here,we synthesize a reduced graphene oxide-basedporous calcium alginate(CA-rGO)hydrogel which exhibits good performance in lightabsorption.More than 90%of the light in the whole spectrum can be absorbed.Meanwhile,the water vapor escapes from the CA-rGO film extremely fast.The waterevaporation rate is 1.47 kg·m^(-2)·h^(-1),corresponding to the efficiency 77%under only 1 kW'm 2 irradiation.The high evaporation efficiency is attributed to the distinctive structureof the film,which contains inherent porous structure of hydrogel enabling rapid watertransport throughout the film,and the concave water surfaces formed in the hydrophilicpores provide a large surface area for evaporation.Hydrophobic rGO divides theevaporation surface and provides a longer three-phase evaporation line.The test onmultiple cyclic radiation shows that the material has good stability.The CA-rGO hydrogelmay have promising application as a membrane for solar steam generation indesalination and sewage treatment.