Self-Assemblies of Silver Sulfide Nanocrystals on Various Substrates

Abstract

The influence of the substrate on the morphology of 2D and 3D superlattices made of 5.8 nm silver sulfide nanocrystals coated with dodecanethiol is reported. The two substrates used are highly oriented pyrolytic graphite (HOPG) and molybdenum disulfide (MoS2). The self-assemblies of nanocrystals were characterized with scanning electron microscopy and atomic force microscopy techniques, and it was found that the self-organization in 2D and 3D superlattices markedly differs with the substrate used. These changes in behavior are explained in terms of particle-particle and particle-substrate van der Waals interactions and capillary forces.

Gold adatoms and dimers on relaxed graphite surfaces

“…[1][2][3][4][5] Most commonly, model potentials are used to simulate experimental observations. More accurate, but computationally expensive ab initio approaches 6,7 have been attempted on a relatively small scale, especially for the gold-graphite system of interest here.…”

Silver Nanoparticles with Controlled Dispersity and Their Assembly into Superstructures

“…As shown by Motte et al, those surfaces increase the tendency to form large ordered structures of nanoparticles. [8,9] This may be attributed to the diminished particle/substrate interactions when compared to the rough amorphous carbon film.…”

“…(iii) By using different substrates (amorphous carbon, HOPG) we could verify that the order length strongly depends on the substrate as already reported in the literature. [8,9] The potential of the ACF to give profound information about the structure of self-assembled colloidal crystals is not exhausted by the given evaluations. Hence, it is intended, in the future work, to use the ACF to get more quantitative results for characterizing the degree of ordering and the crystal defects.…”

“…[8][9][10] For the preparation of the TEM samples the particles were dispersed in cyclohexane with a concentration of 1 mg mL À1 . One drop of this solution was put onto a carbon coated copper grid with subjacent absorbent and dried at room temperature and atmospheric pressure for 15 min, although the sample seemed to be already dry after a few seconds.…”

Self‐Assembly of Inorganic Nanocrystals: Emergence of a New Physics

“…However it is not the unique one. Particle-particle and particlesubstrate interactions [24] play an important role in nanocrystal ordering. Hence, even for very close substrates as amorphous carbon or HOPG (Highly Oriented Pyrolitic Graphite), the ordering is better with silver and cobalt nanocrystals on HOPG than amorphous carbon [17] whereas it is the opposite for Ag 2 S. [2] When cobalt (or silver) nanocrystals are able to self organize in compact hexagonal network on long distance (Figure 1), regular periodic arrangement of nanocrystals in 3D superlattices with more than thousand layer of organized nanocrystals takes place (inset c Figure 1) and form supra crystals [14][15][16][17][18] with the X ray diffraction spots of an ordered in fcc structure (inset d Figure 1).…”