S. K. Evstrop’ev

Spectral properties of zinc sulfide sols stabilized by high-molecular polyvinylpyrrolidone

Spectral properties of zinc sulfide sols stabilized by high-molecular polyvinylpyrrolidone have been studied. It is shown that the absorption spectra of colloidal solutions in the UV spectral range are determined by the quantum-confinement effect, exhibiting a dependence of the absorption edge on the size of zinc sulfide nanocrystals.

Forming protective nanoscale coatings based on Al 2 O 3 (Al 2 O 3 –AlF 3 ) on a glass surface

This paper describes the formation of protective nanoscale (10–15 nm thick) coatings composed of Al2O3 (Al2O3–AlF3) on the surface of glasses, using aqueous and water–alcohol solutions of aluminum nitrate. The effect of the concentration and pH of the solutions and the thickness of the coatings and their structure and spectral properties is investigated.

Spectral and Luminescence Properties of Sols and Coatings Containing CdS/ZnS QDs and Polyvinylpyrrolidone

Spectral and luminescence properties of sols and composition coatings containing cadmium and zinc sulfides and high-molecular polyvinylpyrrolidone have been studied. It is shown that the absorption spectra of colloidal solutions in the UV spectral range are determined by the quantum-confinement effect and exhibit a dependence of the absorption edge on the size of cadmium sulfide nanocrystals. The size of forming particles of metal sulfides has been found to decrease with an increase in the relative content of polyvinylpyrrolidone. It is shown that the order of mixing of the initial components when synthesizing sols also determines the difference in the size of forming particles and their spectral properties.

Photocatalytic degradation and sorption of methylene blue on the surface of metal oxides in aqueous solutions of the dye

The photocatalytic activity of some metal oxides and sulfides, as well of С60 fullerene, is compared using the method of photocatalytic degradation of methylene blue simultaneously with comparison of the efficiency of methylene blue adsorption on solid-phase powders of these oxides, sulfides, and fullerene in aqueous solution of the dye in the absence of irradiation.

Mixed oxide (MgO–Y 2 O 3 ) coatings fabricated on glasses from nitrate solutions

This article describes the formation of nanosize MgO–Y 2O3 protective coatings (10–15 nm thick) on the surface of glasses, using aqueous and water–alcohol solutions of magnesium and yttrium nitrates. Based on the results of electron-microscopic and X-ray-phase analyses, the influence of the thickness of the coating on its structure and morphology has been investigated. It is shown that interaction with the glass substrate plays an important role in stabilizing the amorphous structure of coatings consisting of nanoparticles of metal oxides.

Photolysis of Diazo Dye in Aqueous Solutions of Metal Nitrates

The photolysis of Chicago Blue Sky diazo dye is studied. It is experimentally shown that the presence of metal nitrates in aqueous solutions changes the photolysis mechanism and sharply increases the photolysis rate.

The formation of ZnO-based coatings from solutions containing high-molecular polyvinylpyrrolidone

A method for deposition of transparent nanosize ZnO-based coatings on the glass surface from solutions containing high-molecular polyvinylpyrrolidone is described. The method can be used to form transparent homogeneous coatings based on ZnO with an increased energy gap width. It does not require any intricate technological equipment.

Increasing the optical transparency of MgAl 2 O 4 ceramic when two-stage uniaxial pressing is used

This paper presents the results of experiments on increasing the density and optical transparency of MgAl2O4 ceramic when two-stage uniaxial pressing is used. It is experimentally shown that it is possible to obtain high-density (more than 99.3% of the theoretical value) ceramic that possesses high transparency in a wide spectral range when a combination of cold pressing of nanopowders at loads of 200–400 MPa followed by hot pressing of the blanks at a temperature of 1450–1470°C and a pressure of up to 175 MPa is used.

The influence of the polymer-stabilizer molecular weight on the spectral luminescence properties of composite sols and coatings containing PbS quantum dots

The influence of the polyvinylpyrrolidone (PVP) molecular weight on the stability and spectral luminescence properties of sols of lead sulfide nanocrystals and the related composite coatings has been studied. It is shown that the spectral properties of PbS sols stabilized with low-molecular (PVP) and the related coatings are determined to a great extent by the formation of large particle aggregates in these materials and, accordingly, high level of light scattering. It is effective to use low-molecular PVP for preparing powder materials containing PbS quantum dots (QDs), because it allows one to perform fast powder precipitation and form small semiconductor particles. High-molecular PVP provides high aggregative and sedimentation stabilities of semiconductor nanocrystal sols. This polymer is effective for use in preparing stable QD sols and homogeneous coatings transparent in the visible spectral range.

Polymeric immersion coatings

We present experimental results relating to the development of film-forming immersion compounds having a variety of chemical compositions and a wide range of indices of refraction (1.51–1.63). These composite materials contain nontoxic organic compounds whose optimum ratios ensure that they are transparent in the visible region of the spectrum and have high adhesion to the surface of optical glasses and crystals.