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 degrees 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.