Preparation and characterization of colloidal dispersions of layered niobium chalcogenides

Stable colloidal dispersions of niobium chalcogenides NbQ2 and NbQ3 (Q = S, Se) in organic solvents – CH3CN, dmf, iPrOH, EtOH, EtOH/H2O (vol. 1/1), n-BuOH were prepared by ultrasonication. According to DLS and AFM data the particle size distributions in the dispersions are rather wide: particle sizes vary from 70 to 400 nm, and the mean sizes are in range of 150–200 nm. DLS polymodal and monomodal analyses were carried out for the colloidal dispersions of NbQ2 and NbQ3 (Q = S, Se) in acetonitrile. The particles diffusive Brownian motion in the acetonitrile colloidal dispersions is best described by diffusion of disk-shaped particles with monomodal distributions for NbQ3 and bimodal distributions for NbQ2. A series of thin films prepared from the colloidal dispersions show that the particles retain their original crystal structures, at the same time strong texturing of the films appears.