Superior Thermoelectric Properties of Twist-Angle Superlattice Borophene Induced by Interlayer Electrons Transport.

In this paper, the energy bands, interlayer interactions and thermoelectric effects of twisted bilayer borophene (TBB) synthesized on Ag (111) are studied theoretically. The results manifest the advantages of twistronics, where the high electrical conductivity and the large Seebeck coefficient are regulated to the same range, which lead to the significantly increase of figure of merit ZT than that of bilayer borophene (BB) without twist, where the BB without twist is successfully synthesized on Ag (111) film is recently experimental report [Nat. Mater. 2022, 21, 35]. For the TBB synthesized of on Ag (111) film, theoretical analysis demonstrates that TBB and Ag are relatively strongly coupled, and TBB becomes a metallic 2D material, where the top and bottom borophene layers are semiconducting and metallic, respectively. TBB exhibits excellent thermoelectric efficiency due to the charge transfer bonding between the layers, less electron localization, and the regulation of Seebeck coefficient, electrical conductivity, and ZT at the same region of chemical potential and the same temperature by twistronics. The structure-property relationship offers the possibility of applying TBB in thermoelectric devices.

Modulating Thermoelectric Properties of the MoSe2/WSe2 Superlattice Heterostructure by Twist Angles.

In the current era of limited resources, the matter of energy conversion holds significant importance. Thermoelectric materials possess the ability to transform thermal energy into electric power. Achieving an impressive thermoelectric figure of merit (ZT) necessitates the presence of a high power factor alongside low thermal conductivity. Stimulated by recent experimental reports on the in-plane lateral MoSe2/WSe2 heterostructure in the application thermoelectric device [Zhang Y. et al., Simultaneous electrical and thermal rectification in a monolayer lateral heterojunction. Science 2022, 378, 169], in this study, the method of twisting angle is used to modulate the energy bands of van der Waals MoSe2/WSe2 superlattice heterostructures to optimize the carrier concentration, band gap, electric conductance, thermal conductivity, and ZT of the heterostructure. The 21.79° twisted heterostructures among different twisting-angle heterostructures benefit from both the high power factor and low thermal conductivity, ultimately leading to significantly improved ZT compared to the untwisted counterpart.

Polystyrene microspheres with ultra-rough surfaces engineered using RIE technique and applied using SERS.

In this study, we successfully fabricated two ultra-rough surfaces based on polystyrene (PS) microspheres by employing the reactive ion etching (RIE) technique. Elemental analysis confirmed a stable AlF3 composition of the structures of these surfaces. We proposed the mechanism of the formation of these surfaces and performed SERS-related tests; the prepared substrates exhibited excellent SERS performance.

Emerging Characteristics and Properties of Moiré Materials.

In recent years, scientists have conducted extensive research on Moiré materials and have discovered some compelling properties. The Moiré superlattice allows superconductivity through flat-band and strong correlation effects. The presence of flat bands causes the Moiré material to exhibit topological properties as well. Modulating electronic interactions with magnetic fields in Moiré materials enables the fractional quantum Hall effect. In addition, Moiré materials have ferromagnetic and antiferromagnetic properties. By tuning the interlayer coupling and spin interactions of the Moiré superlattice, different magnetic properties can be achieved. Finally, this review also discusses the applications of Moiré materials in the fields of photocurrent, superconductivity, and thermoelectricity. Overall, Moiré superlattices provide a new dimension in the development of two-dimensional materials.

Wafer-scale synthesis of a morphologically controllable silicon ordered array as a platform and its SERS performance.

In this study, we fabricated four different structures using single crystal silicon wafers for surface-enhanced Raman spectroscopy (SERS) applications. For single crystal silicon, different crystal orientations exhibit different physical and chemical properties. In chemical etching, the etching speed of different crystal planes also exhibits significant differences. We first used reactive ion etching (RIE) to process the surface of the substrate, and subsequently used KOH anisotropic wet etching technology to modify the surface of silicon wafers with different crystal orientations and produced four different results. In the RIE stage in an O2 atmosphere, the (110) silicon wafer formed a hexagonal hole structure, and the (100) silicon wafer formed an inverted pyramid hole structure; however, in the RIE-treated substrates in O2 and SF6 atmosphere, the (110) silicon wafer formed a pyramid with a diamond-shaped base, and the (100) silicon wafer showed a columnar structure with a "straw hat" at the top. The formation mechanisms of these four structures were elucidated. We also performed structure-related SERS characterizations of the four different structures and compared their performance differences.

Electric Field Induced Twisted Bilayer Graphene Infrared Plasmon Spectrum.

In this work, we investigate the role of an external electric field in modulating the spectrum and electronic structure behavior of twisted bilayer graphene (TBG) and its physical mechanisms. Through theoretical studies, it is found that the external electric field can drive the relative positions of the conduction band and valence band to some extent. The difference of electric field strength and direction can reduce the original conduction band, and through the Fermi energy level, the band is significantly influenced by the tunable electric field and also increases the density of states of the valence band passing through the Fermi level. Under these two effects, the valence and conduction bands can alternately fold, causing drastic changes in spectrum behavior. In turn, the plasmon spectrum of TBG varies from semiconductor to metal. The dielectric function of TBG can exhibit plasmon resonance in a certain range of infrared.

The physical mechanism of electron excitation spectrum for photo redox device controlled by gate voltage, a first-principles study.

This article uses quantum chemical methods and various wave function analysis methods to firstly analyze the optical absorption spectrum and electron migration mechanism of rhodamine 6G molecular complexes on graphene substrates during electron or hole injection. Secondly, since the light absorption properties are very important during photocatalysis, the intermolecular interaction and electronic structure in both cases were calculated and analyzed. Not only the experimental results of the previous photocatalytic devices were explained, but also the physical mechanism was promoted, and the guiding recommendations for the future catalytic device design.