Phase-Selective Synthesis of Copper Sulfide Nanocrystals

Abstract

Monodispersed copper sulfide nanocrystals were synthesized via the decomposition of an air-stable precursor, copper (I) thiobenzoate (CuTB), in the presence of dodecanethiol (DDT). We discover that, by varying the stabilizing agent used (trioctylphosphine or tributylphosphite), we can selectively generate phase-pure roxbyite nanoplates (Cu 1.75 S) or chalcocite faceted nanocrystals (Cu 2 S). We also demonstrate that, under suitable conditions, the roxbyite nanoplates can be forced to grow only in two dimensions, with an aspect ratio (diameter/thickness) tunable between 2.3 and 4.1. To the best of our knowledge, this is the first report for making nanocrystalline copper sulfide with such aspect ratio tunability. Temperature and the [DDT]/[CuTB] ratio were identified to be the important factors for controlling the size of the nanocrystals. To gain more insight to the mechanisms of phase-selective control, we attempted a series of controlled experiments and DFT calculations. It appears that the precursor can undergo two competitive pathways, leading to seeds, and thus the growth, of different crystal phases. This work thus demonstrates a general approach to phase-selective nanocrystals engineering whereby the kinetics of decomposition of a chosen precursor is readily manipulated using activating or stabilizing agents.

Synthesis and assembly of monodisperse spherical Cu2S nanocrystals

“…When the temperature of 200 • C was applied for the injection of DDT, hexagonal Cu 2 S nanodisks with larger size were finally achieved (see Supporting information, Fig. S3), which is similar to the results of the reports as referred [23,27,28]. It was found that if the nucleation temperature was set at a higher temperature (200 • C), while growth temperature was set at a lower temperature (such as 180 • C), uniform spherical Cu 2 S nanocrystals could be obtained even the reaction last for several hours.…”

“…Various Cu 2 S nanostructures such as nanoparticles, nanodisks, nanowires, nanorods, and hexagonal nanoplates have been synthesized by various methods. Recently assembled structures [20][21][22][23][24][25][26][27][28]. For instance, Qian's group prepared ultrathin Cu 2 S nanowire by thermal decomposition of CuS 2 CNEt 2 in a mixture of DDT and oleic acid [21].…”

Characterizing physical properties and in vivo OCT imaging study of Cu-Sn-S nanocrystals

“…[19][20][21] Especially their strong NIR absorption effect by LSPR. This LSPR property can be tunable by manipulating copper deficiency via controlling oxidation/reduction conditions.…”

Sacrificial template synthesis and characterization of photoluminescent silver sulfide nanochains

“…Due to these promising applications, several synthetic methods have been developed to produce nanoscale and micron scale metal chalcogenide nanoparticles including decomposition reactions [20], hydrothermal [21], microemulsions [22], thin films [23], and electrochemical deposition [24]. However, control over composition, shape, and impurities remains a challenge.…”