Phase Engineering of Two-Dimensional Transition Metal Dichalcogenides

Phase engineering of two-dimensional transition metal dichalcogenides (2D TMDs) centres on the controlled conversion between distinct crystallographic polytypes to tailor electrical, optical and catalytic properties. The most widely studied transformation is the reversible switch between the trigonal prismatic semiconducting 2H phase and the octahedral metallic 1T or distorted 1T′ phases, realised by chemical intercalation, electrochemical treatment or strain. Recent advances have moved beyond bulk lithiation agents towards light‐mediated and template‐directed strategies, enabling rapid, high‐resolution patterning of phase domains at ambient conditions. By exploiting phase‐specific conductivity and surface activity, researchers have demonstrated enhanced transistor contacts, efficient electrocatalysts for hydrogen evolution, and tunable heterostructures with engineered band alignments. These developments underscore the potential of phase engineering to integrate multifunctional 2D TMD elements in next-generation electronics, optoelectronics and energy conversion technologies.

Research from Nature Portfolio

Recent studies have harnessed photoredox phase engineering to accelerate the 2H→1T transition in monolayer and bilayer TMDs by up to six orders of magnitude under low‐power visible illumination. This approach not only illuminates the underlying charge‐transfer kinetics but also permits the replacement of hazardous n-butyllithium with safer organolithiation reagents, yielding high-quality metallic domains and sub-diffraction-limited phase patterns for device integration. In parallel, phase-selective in-plane heteroepitaxy has been developed to grow H-phase CrSe2 on lattice-matched MoSe2 nanoribbons. Atomically sharp interfaces exhibit Type-I band alignment and mirror twin boundaries that host one-dimensional electronic states with Tomonaga–Luttinger liquid behaviour, offering a template for property‐driven heterostructure design and phase-specific device functionalities.

Phase Engineering of Two-Dimensional Transition Metal Dichalcogenides publication trend

The graph below shows the total number of articles in phase engineering of two-dimensional transition metal dichalcogenides across all publications each year (not limited to Nature Index journals).

Technical terms

Two-dimensional transition metal dichalcogenides (2D TMDs): Layered semiconductors or metals composed of a transition metal atom sandwiched between chalcogen atoms, offering phase‐dependent electronic and optical properties.

Crystallographic phase: A specific atomic arrangement within a solid that defines its symmetry and electronic character, exemplified by the semiconducting 2H and metallic 1T phases in TMDs.

Photoredox process: A light‐induced redox reaction in which photon absorption accelerates charge transfer, used here to drive phase transitions in 2D materials at ambient conditions.

Heteroepitaxy: The epitaxial growth of one crystalline material on the surface of a different crystalline substrate, enabling the formation of sharp interfaces and tailored heterostructures.

References

1. Photoredox phase engineering of transition metal dichalcogenides. Nature (2024).
2. Phase-selective in-plane heteroepitaxial growth of H-phase CrSe2. Nature Communications (2024).
3. Characterization of few-layer 1T-MoSe2 and its superior performance in the visible-light induced hydrogen evolution reaction. APL Materials (2014).
4. Metallic 1T phase source/drain electrodes for field effect transistors from chemical vapor deposited MoS2. APL Materials (2014).
5. Editors’ Choice—Review—Conductive Forms of MoS2 and Their Applications in Energy Storage and Conversion. Journal of The Electrochemical Society (2020).