Solventless Synthesis of Monodisperse Cu₂S Nanorods, Nanodisks, and Nanoplatelets

Abstract

Cu2S nanocrystals with disklike morphologies were synthesized by the solventless thermolysis of a copper alkylthiolate molecular precursor. The nanodisks ranged from circular to hexagonal prisms from 3 to 150 nm in diameter and 3 to 12 nm in thickness depending on the growth conditions. High resolution transmission electron microscopy (HRTEM) revealed the high chalcocite (hexagonal) crystal structure oriented with the c-axis ([001] direction) orthogonal to the favored growth direction. This disk morphology is thermodynamically favored as it allows the extension of the higher energy {100} and {110} surfaces with respect to the {001} planes. The hexagonal prism morphology also appears to relate to increased C-S bond cleavage of adsorbed dodecanethiol along the more energetic {100} facets relative to {001} facets. Monodisperse Cu2S nanodisks self-assemble into ribbons of stacked platelets. This solventless approach provides a new technique to synthesize anisotropic metal chalcogenide nanostructures with shapes that depend on both the face-sensitive thermodynamic surface energy and the surface reactivity.

Charge Transport in Cu2S Nanocrystals Arrays: Effects of Crystallite Size and Ligand Length

“…The crystallite facets are far more pronounced in the "large" 14 nm NCs than in the "smaller" ones. This is in accordance to previous reports of smaller nano-crystals that have a less defined crystal structure and faceting [25]. The devices were prepared by depositing the suspension of NCs in chloroform, employing a slow evaporation controlled method, onto Si/SiO 2 substrates with pre-patterned source-drain electrodes (Cr/Au, 2 μm spacing).…”

Morphology and Composition-Controls of Cu<I><SUB>x</SUB></I>S Nanocrystals Using Alkyl-Amine Ligands

“…The solution phase synthesis of copper sulfide NCs have been based upon a sulfur oleylamine system 5,6) or a thermolysis of single-source precursor such as copper thiolat 7,8) and Cu(S 2 CNEt 2 ) 2 . 9) Recently, Korgel et al reported the composition control of copper sulfide NCs by changing the Cu/S source ratio.…”

Size Dependence of a Temperature-Induced Solid–Solid Phase Transition in Copper(I) Sulfide

“…Our results also provide context for several reported observations of high chalcocite phases in nanoparticles existing at low temperatures. 11,13 The uniquely low-temperature solid-solid transition observed for copper(I) sulfide suggests real-world applicability of this phase-change material, while making a broader call for characterization of additional materials whose phase diagrams enable transitions between functional crystal phases at room temperature.…”