A Colloidal Synthesis Route Towards AgBiS₂ Nanocrystals Based on Metal Xanthate Precursors

Abstract

Silver bismuth sulfide (AgBiS 2 ) is showing impressive thermoelectric and photovoltaic properties and has a high potential to replace toxic cadmium or lead containing semiconductors in many applications. Herein, we report on a synthesis route for AgBiS 2 nanocrystals applying metal xanthates as precursors. Silver xanthates could not be used so far in solution-based syntheses for Ag-containing metal sulfide nanocrystals as they are typically insoluble in organic solvents. An investigation of the synthesis process revealed that even though the silver xanthate is not soluble in the used solvent mixture consisting of octadecene and oleylamine, the decomposition of both precursors and the formation of AgBiS 2 nanocrystals is initiated already at room temperature by the amine functionality of the ligand. At room temperature, primary crystallite sizes of approximately 4 nm are observed and at a reaction temperature of 200 °C, the size of the AgBiS 2 nanocrystals increases to 7-8 nm.

Molecular Precursor Routes for Ag-Based Metallic, Intermetallic, and Metal Sulfide Nanoparticles: Their Comparative ORR Activity Trend at Solid|Liquid and Liquid|Liquid Interfaces

“…Interestingly, the introduction of TOP resulted in the formation of pure silver from the xanthate complex, despite the fact that the silver complex showed higher stability by TGA analysis, and Ag and S atoms of the complex are directly bonded. 31 The p-XRD analysis indicates the formation of highly crystalline elemental silver and there was no indication of Ag 2 S impurity (Figure 1c). The TEM analysis shows that Ag nanoparticles are spherical with a uniform size and shape (Figures 2c and S4).…”

“…The transformation of metal–organic precursor into metallic Ag nanoparticles was performed by following similar reaction conditions, except that ODE was replaced by TOP (3.0 mL). Interestingly, the introduction of TOP resulted in the formation of pure silver from the xanthate complex, despite the fact that the silver complex showed higher stability by TGA analysis, and Ag and S atoms of the complex are directly bonded . The p -XRD analysis indicates the formation of highly crystalline elemental silver and there was no indication of Ag 2 S impurity (Figure c).…”

“…Lee et al converted functionalized graphene oxide to reduced graphene by using TOP, which was oxidized to trioctylphosphine oxide (TOPO). 32 Mews et al reported the synthesis of Bi nanoparticles by reduction of BiCl 3 and Bi[N(SiMe 3 ) 2 ] 3 precursors using only TOP, and 31 P NMR spectrum confirmed the complete oxidation of TOP to TOPO. 33 Furthermore, the comparative p-XRD analysis of the metal complexes and the residual materials also confirms the decomposition of the respective metal complexes in the presence of TOP (Figure S8).…”