Synthesis of Zn1–xCdxS nanocrystals by electrolytic method

The possibility of obtaining nanocrystals of the solid solution of zinc and cadmium sulfides by electrolytic method was investigated. Sodium thiosulfate solution in distilled water was used as an electrolyte. It was shown that the composition of the synthesized nanocrystals depends on the electrodes that served as sources of cadmium and zinc ions. X-ray diffraction method was used to determine the size of nanoparticles and type of the crystal structure. The size of the nanocrystals was calculated using Debye-Scherrer equation. It was found that the Zn1–xCdxS (х = 0, 0.07, 1) nanoparticles crystallize in the cubic sphalerite structure at room temperature of the electrolyte. The crystal lattice parameter of Zn0.93Cd0.07S (a = 0.5432 nm) has an intermediate value between those of the cubic ZnS (a = 0.5402 nm) and CdS (a = 0.5887 nm). A good agreement between the obtained results and the literature values were established. The change of the unit cell parameters of the ZnS-CdS solid solution is described by the Vegard’s law. Differential thermal analysis of the Zn0.93Cd0.07S solid solution in the temperature range of 150-550 ^oС was performed for the first time. It was determined that the synthesized Zn0.93Cd0.07S nanoparticles contain a large amount of adsorbed water at room temperature. With the subsequent heating of the evacuated ampoule with nanoparticle, thermal effects at 185°C, 335°C, and 475°C were established for the first time. The phase transition sphalerite-wurtzite after annealing of the solid solution at 550°С was observed. The thermal effects have been analyzed and compared with the available literature data.