First principles studies on electronic and contact properties of Single layer 2H-MoS2/1T'-MX2 heterojunctions

With in-plane heterojunction contacts between semiconducting 2H phase (as channel) and the metallic 1T' phase (as electrode), the two-dimensional (2D) transition metal chalcogenides (TMDs) field-effect transistors (FETs) have received much...

Interface Engineering of Heterogeneous Transition Metal Chalcogenides for Electrocatalytic Hydrogen Evolution

MoS2 and MoSe2 are recognized as the promising electrocatalysts for hydrogen evolution reaction (HER), but the active sites are mainly located on the edge, limiting their electrochemical efficiency. Here we...

Emergent high superconductivity in layered TaS3 crystal

Transition metal chalcogenides (TMCs) have attracted increasing attention due to their rich polymorphs and unique properties, i.e. pressure-induced superconductivity. In this work, we systematically investigated phase diagram, stability, and superconducting...

Investigation of Phase Segregation in p-Type Bi0.5Sb1.5Te3 Thermoelectric Alloys by In Situ Melt Spinning to Determine Possible Carrier Filtering Effect

One means of enhancing the performance of thermoelectric materials is to generate secondary nanoprecipitates of metallic or semiconducting properties in a thermoelectric matrix, to form proper band bending and, in turn, to induce a low-energy carrier filtering effect. However, forming nanocomposites is challenging, and proper band bending relationships with secondary phases are largely unknown. Herein, we investigate the in situ phase segregation behavior during melt spinning with various metal elements, including Ti, V, Nb, Mo, W, Ni, Pd, and Cu, in p-type Bi0.5Sb1.5Te3 (BST) thermoelectric alloys. The results showed that various metal chalcogenides were formed, which were related to the added metal elements as secondary phases. The electrical conductivity, Seebeck coefficient, and thermal conductivity of the BST composite with various secondary phases were measured and compared with those of pristine BST alloys. Possible band alignments with the secondary phases are introduced, which could be utilized for further investigation of a possible carrier filtering effect when forming nanocomposites.

Recent Progress and Approaches on Transition Metal Chalcogenides for Hydrogen Production

Development of efficient and affordable photocatalysts is of great significance for energy production and environmental sustainability. Transition metal chalcogenides (TMCs) with particle sizes in the 1–100 nm have been used for various applications such as photocatalysis, photovoltaic, and energy storage due to their quantum confinement effect, optoelectronic behavior, and their stability. In particular, TMCs and their heterostructures have great potential as an emerging inexpensive and sustainable alternative to metal-based catalysts for hydrogen evolution. Herein, the methods used for the fabrication of TMCs, characterization techniques employed, and the different methods of solar hydrogen production by using different TMCs as photocatalyst are reviewed. This review provides a summary of TMC photocatalysts for hydrogen production.