: 79-84
Lviv Polytechnic National University
Lviv Polytechnic National University
Lviv Polytechnic National University

One of the promising methods of such a modification is a method of galvanic replacement, which is characterized by wide possibilities of controlled influence on the morphology of the deposited nanostructured metal. The deposition of silver by galvanic replacement is most studied in aqueous solutions of AgNO3 in the presence of HF. However, the hydrolysis of formed compounds of silicon, the change in pH, and the electrical renewal of hydrogen do not always provide a controlled formation of metal nanoparticles. Therefore, as an alternative, in recent years, the processes of galvanic replacement in the environment of organic solvents are investigated, which prevents the course of side chemical and electrochemical processes. The environment of organic aprotic solvents contributes to the formation of spherical metal particles and the 2D filling of silicon surfaces during electroplating. The proposed work is devoted to the study of the regularities of the electroplating substitution process for obtaining nanostructured silver precipitates on a silicon substrate from aqueous solutions of cyanide complexes and in a DMF medium. The results of studies of the process of depositing nanostructured silver on the silicon surface by the electroplating substitution method are given. It is shown that the formation of discrete particles of spherical shape with a large range of sizes (80 ... 200 nm) is characteristic for galvanic substitution of silver on silicon from solutions of AgNO3 in DMF. For the restoration of silver from solutions of the cyanocomplex, the formation of silver nanoparticles is much smaller in size (60 ... 80 nm) and their uniform distribution on the surface of the silicon substrate. Therefore, for the modification of silicon only silver nanoparticles with a small range of their distribution in size are determining galvanic replacement in solutions of stable complex compounds of Argentum in DMF. It has been established that due to the elevated temperature of galvanic substitution in AgNO3 solution in DMF from 20 to 40 oC, the size of silver particles and the geometry of the sediment do not significantly change. There is a tendency for agglomeration of silver particles and an increase in the density of filling the silicon surface with a precipitate due to the weakening of adsorption of molecules of aprotic organic solvent DMF with silver sedimentation. In addition, the cathodic polarization decreases with increasing temperature.

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