Strategies on Phase Control in Transition Metal Dichalcogenides

Abstract

Transition metal dichalcogenides (TMDs) consist of dozens of ultrathin layered materials that have significantly different properties due to their varied phases, which determine the properties and application range of TMDs. Interestingly, a controllable phase transition in TMDs is achieved extensively with the use of several methods. Thus, phase control is a promising way to fully exploit the potential of TMDs. This review introduces the recent rapid development of the study of the TMD phase control, starting from the basic conception of the phase and phase transition in TMDs to the strategies for obtaining phase control. The different strategies are roughly classified into several types based on their characteristics: doping, synthesis method, strain, thermal method, and interlayer coupling. Finally, an evaluation on the prospect of the emergent strategies is provided.

Phase-controllable growth of ultrathin 2D magnetic FeTe crystals

“…One of the most important features of FeTe is its phase tunability which originates from the formation energy difference between the hexagonal and tetragonal phases in FeTe 13 , 14 . Theoretical calculations have predicted that the hexagonal FeTe is the most thermodynamically favorable phase 16 , 19 , 21 . Thus, the growth temperature in the CVD process is essential to realize the phase transition.…”

Nanoarchitectonics for Transition‐Metal‐Sulfide‐Based Electrocatalysts for Water Splitting

“…For example, 2H-MoS 2 is a semiconductor that is attractive to electronic devices, 1T-MoS 2 possesses metallic property which has advantages in electrocatalysis, and 3R-MoS 2 is a non-centrosymmetric semiconductor that has potential in nonlinear optics. [2,3] Moreover, the electrochemical properties of MS 2 are bound up with their surface orientation. For single S-M-S trilayer, it exists two kinds of surface sites-the basal plane and the edge, which have been reported to demonstrate anisotropic properties.…”

“…Step 1: H 3 O + + e -+ * → H* + H 2 O, in acidic electrolyte [1] H 2 O + e -+ * → H* + OH -, in alkaline electrolyte [2] Step 2: H* + H* → H 2 , Tafel reaction [3] H* + H 3 O + + e -→ H 2 + H 2 O, Heyrovský reaction [4] Where * represents the catalysts on the surface, H* is absorbed hydrogen intermediates.…”

Emerging in‐plane anisotropic two‐dimensional materials

“…Transition metal dichalcogenides (TMDs) (eg, MoS 2 and WSe 2 etc.) are another class of 2D materials possesses a size-tunable band gap, [16][17][18] which have been utilized in field-effect transistors (FETs), photodetectors, and solar cells, [19][20][21][22] showing the potential to approach the technological gap where graphene left. 23 The similarity between graphene and MoS 2 is that their 2D crystal lattices are highly symmetrical, leading almost isotropic in-plane physical properties.…”