Thesis for the degree of Doctor of Chemical Sciences, specialty 02.00.21 Solid State Chemistry. - Yuriy Fedkovich Chernivtsi National University, Chernivtsi, 2021.
In the dissertation, the effect of the thermodynamic synthesis conditions on the electronic, crystalline structure and size of metal and semiconductor nanoparticles, the creation of hybrid semiconductor-metal structures and composites with the composition of CdTe / CdS nanocrystals - single crystals of inorganic salts, as well as the influence of external parameters on the optical properties of the synthesized materials are studied.
In particular, for the first time:
The methods of photostimulated synthesis for obtaining nanoparticles of silver of decahedral, spherical, and prismatic forms, porous nanorods of gold are investigated and generalized, the redox nature of such reactions is established.
It was found that when irradiated with light with a wavelength of 450-460 nm, a solution of Ag nanoparticles stabilized with benzoates undergoes successive agglomeration and aggregation of these particles. Local heating of the medium between the particles due to plasmon resonance plays a crucial role in these processes.
The optimal sizes of gold and silver nanorods for their use as plasmon sensors have been established. Methods for obtaining porous nanostructures based on gold nanorods with high plasmon sensitivity in the visible range and improved catalytic properties have been developed. The influence of thin carbon shells on the thermal stability of gold and silver nanoparticles has been established.
The use of nanotracking and dark field polarization microscopy to study the size and symmetry of metal nanoparticles is proposed.
Methods of photostimulated synthesis of metal-semiconductor hybrid nanostructures, in particular with a rod-shaped semiconductor part and a spherical gold domain, have been improved. Methods for obtaining such systems suitable for catalytic reduction of paranitrophenol have been developed.
Methods of advanced synthesis and doping of cadmium telluride nanoparticles with Mn, Zn, and Hg are proposed, which leads to the expansion of their photoluminescence range and enables use in optical transducers and display systems.
Methods for obtaining solid-state composite materials of inorganic salt - nanoparticles, in which the matrix is potassium dihydrogen phosphate, calcium carbonate, potassium bromide, and sodium chloride, and the nanocrystalline phase - quantum dots of cadmium telluride with a sulfide shell. Theoretical models of the description of photoluminescent processes in such composites are offered, their thermal and photostability, electric parameters are investigated.
The study of the influence of a wide range of parameters on the growth of composite crystals allows us to obtain reproducible structures, which is important for the creation of functional materials based on them.
The practical significance lies in the fact that improved and new methods of photostimulated synthesis of metal nanoparticles can be used to obtain large quantities of homogeneous nanoparticles. Methods for the synthesis of metal nanoparticles of various shapes to create refractometric sensor systems in a wide spectral range (from 540 to 800 nm) have been developed. Theoretical preconditions for the creation of sensors based on gold and silver nanoparticles have been developed. Nanomaterials of porous rod structure of gold with improved sensory and catalytic properties were obtained.
Keywords: metals, semiconductors, nanoparticles, composite materials, CdTe, plasmon, sensor, gold, silver.
