Synthesis of copper and zinc sulfide nanocrystals via thermolysis of the polymetallic thiolate cage

Abstract

In this paper report on the synthesis of copper and zinc sulfide nanocrystals (NCs) via the formation of polymetallic thiolate cages. Cu 2 S NCs derived from Cu-dodecanethiol complex formed well-defined spherers, which were sufficiently monodisperse (with a size distribution of w10% standard deviation of approximately 4.7 nm diameter on average) to generate ordered self-assemblies. An electron diffraction pattern and UV-vis spectrum of Cu 2 S NCs indicate that this process can provide pure b-chalcocite (Cu 2 S). Nearly monodisperse ZnS NCs with a size ranging from 3 to 7 nm were obtained by thermolysis of the S-Zn-dodecanethiol precursor. The electron diffraction pattern indicates that zinc sulfide NCs are either wurtzite or a mixture of wurtzite and zincblende. TEM observation and UV-vis spectra revealed that the growth rate of ZnS NCs depends strongly on the annealing temperature. UV-vis spectra of 3 nm ZnS NCs show sharp excitonic features and a large blue shift from the bulk material. The photoluminescence spectra exhibit a large red shift from the absorption band edges. These shifts could be attributed to recombination from the surface traps. The narrow size distribution of Cu 2 S and ZnS NCs led to the formation of ordered self-assemblies with various well-defined but nonclosed-packing. q

Synthesis of wurtzite-phase ZnS nanocrystal and its optical properties

“…Here, we have reported the synthesis of hexagonal wurtzite phase of ZnS NCs through annealing of the cubic ZnS nanoparticles, prepared through chemical precipitation method [18]. Annealing process is effective for reproducible size control of NCs and also it can be used to improve the crystal quality and stability which are required for device purposes [23][24][25]. There is only one report [24], so far, on annealing treatment of colloidal ZnS NCs, to the best of our knowledge.…”

Phase-controlled synthesis of ZnS nanocrystallites by mild solvothermal decomposition of an air-stable single-source molecular precursor

“…As a fruitful and promising way being pursued in the synthesis of semiconducting metal chalcogenide materials, the single-source molecular precursor (an individual molecule containing all the elements required in the final product) route has several appealing features [5][6][7]11,[19][20][21][22][23][24][25][26][27][28]. First of all, it offers the potential advantages of mildness, safety and simplified fabrication procedure and equipment, when compared with the use of multiple sources requiring exact control over stoichiometry, and it is a one-step synthesis compatible with the established metallorganic chemical vapor deposition [19][20][21][22][23].…”

“…First of all, it offers the potential advantages of mildness, safety and simplified fabrication procedure and equipment, when compared with the use of multiple sources requiring exact control over stoichiometry, and it is a one-step synthesis compatible with the established metallorganic chemical vapor deposition [19][20][21][22][23]. Another important motivation for the utilization of single-source molecular precursors may be found in the observation of unusual crystal growth selectivity or metastable phase formation of the resultant products, which are sometimes unattainable with the conventional synthetic techniques [5][6][7]11,[24][25][26][27][28]. Herein, we report a preliminary study concerning the phasecontrolled synthesis of ZnS nanocrystallites by low-temperature (150-200 1C) solvothermal decomposition of an air-stable, easily obtained single-source molecular precursor (Zn-(DDTC) 2 ) in the two most common and cheap solvents, distilled water and ethanol.…”

Facile synthesis and step by step enhancement of blue photoluminescence from Ag-doped ZnS quantum dots

“…To enhance the PL properties, ZnS:Ag,Al QDs were prepared using co-precipitation [12,22] further divided into three parts and subjected to ambient conditions, UVP and UVP+PSH treatments, respectively. For UVP, the samples were irradiated for ~180 minutes by 125 W high flux UV lamp having wavelength of 365 nm, whereas, for PSH treatment, the UV irradiated sample was cooked with a polysulphide solution in a high temperature-pressure autoclave for 2 hours.…”

“…There exist reports on blue PL from ZnS QD systems also, which is mostly attributed from the surface related defect states [19][20][21][22] and/or Ag + doping in ZnS QDs [17].…”