Mechanistic Studies on the Nucleation of Zinc Sulphide Nanoparticles by Means of XAFS Spectroscopy

Abstract

Mechanistic studies on the nucleation of zinc sulphide nanoparticles from thioacetic acid were performed by means of X-ray absorption fine structure spectroscopy. Solutions of thioacetic acid and zinc salt (acetate or oxide) dissolved in a solvent (acetic acid or acetone) were investigated and compared with the corresponding zinc precursor and crystalline zinc sulphide to study the evolution of the structural environment around the zinc atoms in the solution. The investigations reveal that the coordination of sulphur atoms take place immediately when the mixture is prepared and zinc-sulphur species gradually evolve during the course of the reaction. However, the complete formation of zinc sulphide could not be evidenced even after a considerable period of time. This is likely due to the presence of unreacted zinc-oxygen species. The obtained results indicate that, once dissolved, zinc oxide reacts comparatively faster with thioacetic acid than with zinc acetate and that the choice of the reaction medium plays a crucial role in determining the kinetics and mechanism of zinc sulphide nucleation.

Pursuing the Crystallization of Mono- and Polymetallic Nanosized Crystalline Inorganic Compounds by Low-Temperature Wet-Chemistry and Colloidal Routes

“…In detail, the optimized methodology was based on the fast nucleation of the sulfide triggered by the reaction of thioacetic acid (acting as a slowly releasing sulfide source) with water and copper carboxylates (acetate, propionate) in the corresponding carboxylic acid (acetic, propionic) as a low dielectric constant and viscous solvent. The same authors also investigated by X-ray absorption spectroscopy the nucleation of zinc sulfide nanoparticles from thioacetic acid.…”

Ammonia‐free, room temperature, and reusable photochemical bath for the deposition ofZn(S,O)buffer layers inCu(In,Ga)Se2thin‐film solar cells

“…Thioacetic acid is commonly used as a sulfur precursor for the synthesis of ZnS nanoparticles either for the preparation of intermediate zinc complexes such as, for example, Zn(SOCCH 3 ) 2 Lut 2 (di‐3,5 dimethylpiridinebis(thioacetato) zinc(II)) species leading to mesoporous ZnS after heat treatment, or as a sulfur donor in various solvent promoting zinc sulfide synthesis after heating . However, in all cases, the formation of zinc sulfide occurs after reaction times between 30 minutes and 24 hours depending on the experimental conditions.…”

Very low temperature wet-chemistry colloidal routes for mono- and polymetallic nanosized crystalline inorganic compounds

“…In the last years, we have approached different metal oxides and sulphide systems (pure, mixed and/or doped) by using classical sol-gel routes [8][9][10][11][12] or colloidal approaches involving the nucleation/growth of the target structures in suitably optimised solutions/suspensions [13][14][15]. The former approach involved a post-synthesis thermal treatment at temperature typically higher than those addressed in this contribution, and will therefore not be dealt with further.…”

“…The former approach involved a post-synthesis thermal treatment at temperature typically higher than those addressed in this contribution, and will therefore not be dealt with further. The latter strategy instead afforded the formation of crystalline ZnO [15], CuS [13] or ZnS [14] already at room temperature, without the need of postprocessing, and will therefore be described in greater detail in the following paragraphs. ZnO is a very intensively investigated material: its properties, applications [16][17][18][19][20][21][22][23][24][25][26][27][28] and synthesis route have been extensively reviewed by several authors [29][30][31][32][33][34][35][36][37][38][39][40][41][42], to which interested readers are referred.…”