On the importance of the electric double layer structure in aqueous electrocatalysis

To design electrochemical interfaces for efficient electric-chemical energy interconversion, it is critical to reveal the electric double layer (EDL) structure and relate it with electrochemical activity; nonetheless, this has been a long-standing challenge. Of particular, no molecular-level theories have fully explained the characteristic two peaks arising in the potential-dependence of the EDL capacitance, which is sensitively dependent on the EDL structure. We herein demonstrate that our first-principles-based molecular simulation reproduces the experimental capacitance peaks.

Unraveling Heat Transport and Dissipation in Suspended MoSe 2 from Bulk to Monolayer

Understanding heat flow in layered transition metal dichalcogenide (TMD) crystals is crucial for applications exploiting these materials. Despite significant efforts, several basic thermal transport properties of TMDs are currently not well understood, in particular how transport is affected by material thickness and the material’s environment. This combined experimental–theoretical study establishes a unifying physical picture of the intrinsic lattice thermal conductivity of the representative TMD MoSe 2 .

Evidence for equilibrium exciton condensation in monolayer WTe2

We present evidence that the two-dimensional bulk of monolayer WTe 2 contains electrons and holes bound by Coulomb attraction—excitons—that spontaneously form in thermal equilibrium. On cooling from room temperature to 100 K, the conductivity develops a V-shaped dependence on electrostatic doping, while the chemical potential develops a step at the neutral point. These features are much sharper than is possible in an independent-electron picture, but they can be accounted for if electrons and holes interact strongly and are paired in equilibrium.

Edge-Mediated Annihilation of Vacancy Clusters in Monolayer Molybdenum Diselenide (MoSe2) under Electron Beam Irradiation

Annihilation of vacancy clusters in monolayer molybdenum diselenide (MoSe 2 ) under electron beam irradiation is reported. In situ high-resolution transmission electron microscopy observation reveals that the annihilation is achieved by diffusion of vacancies to the free edge near the vacancy clusters. Monte Carlo simulations confirm that it is energetically favorable for the vacancies to locate at the free edge.

Manipulation of spin transport in graphene/transition metal dichalcogenide heterobilayers upon twisting

Proximity effects between layered materials trigger a plethora of novel and exotic quantum transport phenomena. Besides, the capability to modulate the nature and strength of proximity effects by changing crystalline and interfacial symmetries offers a vast playground to optimize physical properties of relevance for innovative applications. In this work, we use large-scale first principles calculations to demonstrate that strain and twist-angle strongly vary the spin–orbit coupling (SOC) in graphene/transition metal dichalcogenide heterobilayers.

Substrate strain tunes operando geometric distortion and oxygen reduction activity of CuN2C2 single-atom sites

Single-atom catalysts are becoming increasingly significant to numerous energy conversion reactions. However, their rational design and construction remain quite challenging due to the poorly understood structure–function relationship. Here we demonstrate the dynamic behavior of CuN2C2 site during operando oxygen reduction reaction, revealing a substrate-strain tuned geometry distortion of active sites and its correlation with the activity. Our best CuN2C2 site, on carbon nanotube with 8 nm diameter, delivers a sixfold activity promotion relative to graphene.

Boosted Solar Light Absorbance in PdS 2 /PtS 2 Vertical Heterostructures for Ultrathin Photovoltaic Devices

Transition-metal dichalcogenides (TMDs) represent a class of materials whose archetypes, such as MoS2 and WS2 , possess exceptional electronic and optical properties and have been massively exploited in optoelectronic applications. The layered structure allows for their exfoliation to two-dimensional samples with atomic thickness (≲ 1 nm), promising for ultrathin, ultralight devices.

Atomic-scale defects restricting structural superlubricity: Ab initio study study on the example of the twisted graphene bilayer

The potential energy surface (PES) of interlayer interaction of twisted bilayer graphene with vacancies in one of the layers is investigated via density functional theory (DFT) calculations with van der Waals corrections. These calculations give a non-negligible magnitude of PES corrugation of 28 meV per vacancy and barriers for relative sliding of the layers of 7–8 meV per vacancy for the moiré pattern with coprime indices (2,1) (twist angle 21.8 ◦ ).

Shear and Breathing Modes of Layered Materials

Layered materials (LMs), such as graphite, hexagonal boron nitride, and transition-metal dichalcogenides, are at the center of an ever-increasing research effort, due to their scientific and technological relevance. Raman and infrared spectroscopies are accurate, non-destructive approaches to determine a wide range of properties, including the number of layers, N, and the strength of the interlayer interactions.