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.