A Facile “Dispersion–Decomposition” Route to Metal Sulfide Nanocrystals

Abstract

In this paper, we demonstrate a simple and general "dispersion-decomposition" approach to the synthesis of metal sulfide nanocrystals with the assistance of alkylthiol. This is a direct heating process without precursor injection. By using inorganic metal salts and alkylthiol as the raw materials, high-quality Ag(2)S, Cu(2)S, PbS, Ni(3)S(4), CdS, and ZnS nanocrystals were successfully synthesized. The mechanism study shows that the reaction undergoes two steps. A key intermediate compound, metal thiolate, is generated first. It melts and disperses into the solvent at a relatively low temperature, and then it decomposes into metal sulfide as a single precursor upon heating. This method avoids using toxic phosphine agent and injection during the reaction process. The size and shape of the nanocrystal can be also controlled by the concentration of the reactant and ligands. Furthermore, the optical properties and assembly of the nanocrystals have also been studied. This report provides a facile, direct-heating "dispersion-decomposition" approach to synthesize metal sulfides nanocrystals that has potential for future large-scale synthesis.

Solution-Processed Environmentally Friendly Ag2S Colloidal Quantum Dot Solar Cells with Broad Spectral Absorption

“…Ag 2 S colloidal quantum dots (CQDs) were synthesized according to literature [27] with some modification. In short, 680 mg (4 mmol) AgNO3 and 33.8 g (40 mL) dodecanethiol (DT) was placed in a 100 mL three-necked flask.…”

“…However, this method is difficult to implement at an industrial level as the injection of sulphur precursor is usually performed at a timescale of around a second, which becomes increasingly more difficult at larger volumes. The heat-up synthesis can therefore be advantageous due to its simplicity, and the potential to more easily upscale the synthesis and that the properties (e.g., size and optical properties) from batch to batch are very similar [27].…”

Synthesis of High‐Quality Wurtzite Cu2ZnSn(S1−x,Sex)4 Nanocrystals With Non‐Toxic Selenium Precursor and the Photoelectrochemical Performance of ZnO NAs/CZTSSe Heterojunction

“…The key factors for the formation of wurtzite CZTS and CZTSSe rather than kesterite are the use of DDT and Se‐ODA in the reactions, respectively (Figures S3 and S4, in Supporting Information). DDT could react with the metal cations to form metal thiolates precursor at low temperature . When the Se‐ODA was added into the metal‐thiols precursor, it could be foremost reduced by DDT in the presence of alkylamine and generate soluble alkylammonium selenide .…”

Understanding of the major reactions in solution synthesis of functional nanomaterials

“…The hot-injection method has been successfully generalized to high-quaity ZnSe, ZnS [313][314][315], PbS [316], PbSe, PbTe [317,318], InAs, InP [319,320] and so on. For the effort in seeking "non-injection" methods for semiconductor NCs, Our group developed a facile "dispersion-decomposition" route to metal sulfide NCs with the help of alkanethiol [321] (Fig. 18).…”