Concentrated Colloidal Dispersion of Nickelladithiolene Coordination Nanosheet Realized by an Alkylated Modulator

Nickelladithiolene nanosheet, Ni₃BHT, is a two-dimensional material composed of nickel ions and benzenehexathiol (BHT). Ni₃BHT has attracted considerable attention owing to its electrical conductivity. Although conventional Ni₃BHT is obtained as a solid film or powder, recent studies have explored methods for handling Ni₃BHT as a liquid ink, which facilitates industrial applications. One such method involves adding a modulator ligand to control the morphology of Ni₃BHT. In this study, we developed a novel modulator ligand, 4,5-dihexylbenzene-1,2-dithiol (CL1), which afforded a more stable and concentrated Ni₃BHT dispersion than those previously reported. Further investigations suggest that CL1 is incorporated not only at the termini but also within the interior of the Ni₃BHT nanoflakes, based on the consistent interpretation of spectroscopic and morphological data, in the dispersion via the addition of an adequate amount of a modulator. The application of the Ni₃BHT dispersion as a conductive ink was demonstrated. The Ni₃BHT ink exhibited the highest electrical conductivity and colloidal stability at a CL1/BHT ratio of 0.3. These findings pave the way for potential applications of Ni₃BHT in various industries.