Interaction of Water-Soluble CdTe Quantum Dots with Bovine Serum Albumin

Semiconductor nanoparticles (quantum dots) are promising fluorescent markers, but it is very little known about interaction of quantum dots with biological molecules. In this study, interaction of CdTe quantum dots coated with thioglycolic acid (TGA) with bovine serum albumin was investigated. Steady state spectroscopy, atomic force microscopy, electron microscopy and dynamic light scattering methods were used. It was explored how bovine serum albumin affects stability and spectral properties of quantum dots in aqueous media. CdTe–TGA quantum dots in aqueous solution appeared to be not stable and precipitated. Interaction with bovine serum albumin significantly enhanced stability and photoluminescence quantum yield of quantum dots and prevented quantum dots from aggregating

Morphotropic phase boundary in Sm-substituted BiFeO3 ceramics: Local vs microscopic approaches

Samarium substituted bismuth ferrite (BiFeO3) ceramics prepared by sol-gel synthesis method were studied using both local scale and microscopic measurement techniques in order to clarify an evolution of the crystal structure of the compounds across the morphotropic phase boundary region. X-ray diffraction analysis, transmission and scanning electron microscopies, XPS, EDS/EDX experiments and piezoresponse force microscopy were used to study the structural transitions from the polar active rhombohedral phase to the anti-polar orthorhombic phase and then to the non-polar orthorhombic phase, observed in the Bi1−xSmxFeO3 compounds within the concentration range of 0.08 ≤ x ≤ 0.2. The results obtained by microscopic techniques testify that the compounds in the range of 0.12 ≤ x ≤ 0.15 are characterized by two phase structural state formed by a coexistence of the rhombohedral and the anti-polar orthorhombic phases; two phase structural state observed in the compounds with 0.15<x<0.18 is associated with a coexistence of the anti-polar orthorhombic and the non-polar orthorhombic phases. Local scale measurements have revealed a notable difference in the concentration range ascribed to the morphotropic phase boundary estimated by microscopic measurements, the obtained results testify a wider concentration range ascribed to a coexistence of different structural phases, the background of the mentioned difference is discussed. © 2021 Elsevier B.V.This work was supported by the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 778070 . M.V.S acknowledges Ministry of Science and Higher Education of the Russian Federation within the framework of state support for the creation and development of World-Class Research Centers “Digital biodesign and personalized healthcare” №075-15-2020-926 . Diffraction measurements and analysis (A.A.D. and D.V.K.) were supported by RFBR (projects # 20-58-00030 ) and BRFFR (project # F20R-123 ). Piezoresponse force microscopy investigations were made possible by the Russian Science Foundation (grant 19-72-10076 ). The equipment of the Ural Center for Shared Use “Modern nanotechnology” UrFU was used

The interaction of two ligand containing electroplating solutions. Final decontamination

We suggested previously a cheap and simple way to decontaminate two ligand-containing rinsing waters of metal finishing. Both copper diphosphate containing rinsing wastewater and acidic zinc ammonium containing rinsing wastewater may be decontaminated by mixing with each other, which results in precipitation of solid solutions of copper-zinc-potassium-ammonium diphosphates. This way of decontamination requires no expensive reagents since only a small amount of H2SO4 is needed for pH adjustment. 80-99.5 % of environmentally dangerous substances, viz. zinc, copper and diphosphate, are removed from the mixture. However, Cu2+ and Zn2+ amounts in filtrates significantly exceed discharge consent level (DCL). Moreover, high concentrations of undesirable diphosphate and ammonium ions, which cause the eutrophication of natural water reservoirs, are present in the filtrates. Depending on the waste water composition of the specific plant and the environment protection requirements the goals of the decontamination may be as follows: 1.) To remove Cu2+ and Zn2+ ions below DCL, 2.) To remove Cu2+ and Zn2+ ions below DCL and additionally to lower the amount of phosphates, 3.) To remove Cu2+ and Zn2+ ions below DCL and additionally to lower the amount of phosphates and ammonium. Our investigation has shown, that goal 1 can be easily and cheaply achieved in industry by using lime, goal 2 – by using lime and spent steel etching solution or phosphogypsum. Goal 3 was achieved by precipitating barely soluble fine crystalline MgNH4PO4 .6H2O. It has been determined, that at optimal conditions as much as 95% of NH4 + ions are precipitated, both residual c Cu2+ and c Zn2+ < DCL, and the concentration of soluble phosphates is reduced 5-40 fold

Laser structuring of thin-film solar cells on polymers

A permanent growth of the thin-film electronics market stimulates the development of versatile technologies for patterning thin-film materials on flexible substrates. High repetition rate lasers with a short pulse duration offer new possibilities for high efficiency structuring of conducting, semi-conducting and isolating films. Lasers with the picosecond pulse duration were applied in structuring the complex multilayered Cu(InGa)Se2 (CIGS) solar cells deposited on the polyimide substrate. The wavelength of laser radiation was adjusted depending on optical properties both of the film and the substrate. A narrow processing window of laser fluence and pulse overlap was estimated with both 1064 nm and 355 nm irradiation to remove the molybdenum backcontact off the substrate. The selective removal of ITO, ZnO and CIGS layers was achieved with 355 nm irradiation in the multilayer structure of CIGS without significant damage to the underneath layers. Use of the flat-top laser beam profile should prevent inhomogeneity in ablation. The EDS analysis did not show residues of molybdenum projected onto the walls of ablated channel due to melt extrusion. Processing with picosecond lasers should not cause degradation of photo-electrical properties of the solar cells but verification is required

Electrochemical Formation and Microstructure of Porous Gallium Phosphide

Electrochemical formation and microstructure of porous GaP have been investigated. Nanostructured porous GaP layers of thickness up to ≈ 20 μm were fabricated on n-type (111)-oriented crystalline c-GaP substrates. Studies of microstructure of porous GaP in dependence on electrolyte type and regimes of technological procedure have been carried out by scanning electron microscopy. The samples were characterized by spectroscopic ellipsometry in visible and near UV spectral range. The investigations have shown that the structure and optical response of porous GaP can be efficiently controlled by technological procedure of electrochemical formation. The shape and dimension of pores can be varied from nanometer-scaled cylindrical pores to GaP nanorods

Characterization of Na1.3Al0.3Zr1.7(PO4)3 solid electrolyte ceramics by impedance spectroscopy

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Effect of temperature on shielding efficiency of phosphate-bonded CoFe2O4 – xBaTiO3 multiferroic composite ceramics in microwaves

A series of novel CoFe2O4 – xBaTiO3 (x = 0.6–0.9) phosphate-bonded multifunctional ceramic composites were synthesized and studied both in ‘Salisbury screen’ geometry and as free-standing films in the frequency range of 25–54 GHz and temperature interval of 120–500 K. Experiments prove that the studied system is prospective for shielding applications in both modes providing total transmission losses of the free-standing sample layer of 40 dB for x = 0.9 dominated by absorption and more than 40 dB of reflection losses at resonant conditions in the Salisbury screen geometry. It was demonstrated that the electromagnetic response of multiferroic composite ceramics in microwaves is very sensitive to the temperature changes in the application's significant temperature range, i.e. 150 – 400 K. Notably, a small, i.e. 5 – 10 K, temperature variation drastically changes the shielding efficiency of the Salisbury screen (SER). In particular, SER ≥ 40 dB is achieved in the range of 302–309 K for the sample with x = 0.9, outside of the range SE rapidly decreases to 10–15 dB. The impact of temperature has to be considered for the efficient use of shielding materials in Ka and V bands for different applications