Low-Temperature Solution Synthesis of Few-Layer 1T ′-MoTe2 Nanostructures Exhibiting Lattice Compression.

Molybdenum ditelluride, MoTe₂, is emerging as an important transition-metal dichalcogenide (TMD) material because of its favorable properties relative to other TMDs. The 1T ′ polymorph of MoTe₂ is particularly interesting because it is semimetallic with bands that overlap near the Fermi level, but semiconducting 2H-MoTe₂ is more stable and therefore more accessible synthetically. Metastable 1T ′-MoTe₂ forms directly in solution at 300 °C as uniform colloidal nanostructures that consist of few-layer nanosheets, which appear to exhibit an approx. 1 % lateral lattice compression relative to the bulk analogue. Density functional theory calculations suggest that small grain sizes and polycrystallinity stabilize the 1T ′ phase in the MoTe₂ nanostructures and suppress its transformation back to the more stable 2H polymorph through grain boundary pinning. Raman spectra of the 1T ′-MoTe₂ nanostructures exhibit a laser energy dependence, which could be caused by electronic transitions. [ABSTRACT FROM AUTHOR]