Search

Dynamic Light Scattering is a well-established technique used in particle sizing. An alternative procedure for Dynamic Light Scattering time series processing based on spectral entropy computation and Artificial Neural Networks is described. An error analysis of the proposed method was carried out and the results on both the simulated and on the experimental DLS time series are presented in detail. The results reveal the possibility of designing an advanced sensor capable of detecting particles with a size bigger than a threshold using this alternative for processing the DLS time series. [ABSTRACT FROM AUTHOR]

The size of silver nanoparticles plays a crucial role in their ultimate application in the medical and industrial fields, as their efficacy is enhanced by decreasing dimensions. This study presents two chemical synthesis procedures for obtaining silver particles and compares the results to a commercially available Ag-based product. The first procedure involves laboratory-based chemical reduction using D-glucose (C6H12O6) and NaOH as reducing agents, while the second approach utilizes trisodium citrate dehydrate (C6H5Na3O7·2H2O, TSC). The Ag nanoparticle suspensions were examined using FT-IR and UV-VIS spectroscopy, which indicated the formation of Ag particles. The dimensional properties were investigated using Atomic Force Microscopy (AFM) and confirmed by Dynamic Light Scattering (DLS). The results showed particle size from microparticles to nanoparticles, with a particle size of approximately 60 nm observed for the laboratory-based TSC synthesis approach. [ABSTRACT FROM AUTHOR]

Photovoltaic systems (PV) based on Cu2ZnSn(S, Se)4 (CZTS) solar cells have demonstrated efficiency and high performance. According to the results of comparative studies, the kesterite structure has proven to be ecologically safe and less expensive than other photovoltaic systems. The goal of the present study was to design a disposable high-temperature transparent electrical insulating coating to cover metal plates for photovoltaic devices based on CZTS. The solution was to replace electrically conductive metallics dispersed in a high-temperature siloxane coating with phonon thermal conductivity ceramic particles. Properties of the obtained coating were investigated using different methods. A mathematical model of thermal processes in the film during heating was also developed. For the control sample and the sample with a heat-conducting filler, a quantitative ratio of thermal conductivity was obtained. The research results confirmed the necessary properties of the coating, including resistance to short-term exposure to high temperatures during the synthesis of kesterite. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the decomposition of a toxic organic compound, Rhodamine B, by the photocatalytic activities of undoped and nitrogen-doped ZrO2 thin films, deposited using the HiPIMS technique. The investigation was performed in the presence and in the absence of H2O2, for two types of experimental arrangements: the irradiation of the films, followed by dipping them in the Rhodamine B solutions, and the irradiation of the films dipped in the solution. The two situations were named "direct irradiation" and "indirect irradiation", respectively. Methods like XRD, AFM, XPS, DRS, water/film surface contact angle, and spectrophotometry were used to obtain information on the films' structure, surface morphology, elemental composition of the films surface, optical band gap, hydrophilicity, and photocatalytic activity, respectively. All these properties were described and correlated. By N-doping ZrO2, the films become absorbent in the visible domain, so that the solar light could be efficiently used; the films' hydrophilic properties improve, which is an important fact in self-cleaning applications; and the films' photocatalytic activity for the decomposition of Rhodamine B becomes better. The addition of hydrogen peroxide acted as an inhibitor for all systems and not as an accelerator of the photocatalytic reactions as expected. [ABSTRACT FROM AUTHOR]

Herein, the properties of the organic heterostructures with triple‐layer ZnO/Ag/ZnO as a replacement for ITO and mixed layer containing arylenevinylene oligomer (based on triphenylamine or carbazole) donor and nonfullerene (perylene diimide) acceptor mixed in the ratio 1:2 and the effect of a buffer layer of PEDOT‐PSS intercalated between triple layer and mixed organic layer are discussed. The UV−vis transmission and photoluminescence (PL) properties are investigated in correlation with the surface topography and reveal a good match between the absorption and emission domain, which can favor the generation of the charge carriers. The heterostructure with the mixed layer based on triphenylamine oligomer shows the widest absorption domain, and the PL spectra of the heterostructures realized with either triphenylamine or carbazole oligomer show peaks corresponding to the radiative decay of the donor and acceptor. The I−V characteristics in the dark indicate a slightly nonlinear behavior and the current is affected by the charge carriers recombination on the defects present in the thick mixed layer deposited by matrix‐assisted pulsed laser evaporation. The effect of the PEDOT‐PSS buffer layer on the electrical properties of the organic heterostructure with ZnO/Ag/ZnO electrode is also investigated. [ABSTRACT FROM AUTHOR]

In the presented work, B4C was irradiated with xenon swift heavy ions at the energy of 167 MeV. The irradiation of the substrate was done at room temperature to a fluence of 3.83 × 1014 ion/cm2. The samples were then analyzed with the X-ray diffraction technique to study the structural modification, as it can probe the region of penetration of xenon atoms due to the low atomic number of the two elements involved in the material under study. The nano-cluster formation under ion irradiation was observed. Positron lifetime (PLT) calculations of the secondary point defects forming nanoclusters and introduced into the B4C substrate by hydrogen and helium implantation were also carried out with the Multigrid instead of the K-spAce (MIKA) simulation package. The X-ray diffraction results confirmed that the sample was B4C and it had a rhombohedral crystal structure. The X-ray diffraction indicated an increase in the lattice parameter due to the Swift heavy ion (SHI) irradiation. In B12-CCC, the difference between τ with the saturation of H or He in the defect is nearly 20 ps. Under the same conditions with B11C-CBC, there is approximately twice the value for the same deviation. [ABSTRACT FROM AUTHOR]

Correlation between observed kinetic effects of phase-transfer catalytic reaction of the alkaline hydrolysis of 4-nitrophenyl ester of N-benzyloxycarbonylglycine-4 in the two-phase system chloroform-borate buffer pH = 10 and a content of ionic forms of catalyst was investigated. The phosphonium salts QX (X = Cl¯, Br¯, I¯) shows high catalytic reactivity. Dependence of the reaction kinetics discussed in the framework of the extraction mechanism with a competitive extraction of a nucleophile ОН¯, nucleofuge 4-NO2C6H4O¯ and anion X¯ of the phase-transfer catalyst. [ABSTRACT FROM AUTHOR]

We investigated the optical and electrical properties of flexible single and bi-layer organic heterostructures prepared by vacuum evaporation with a p-type layer of arylenevinylene oligomers, based on carbazole, 3,3′ bis(N hexylcarbazole)vinylbenzene = L13, or triphenylamine, 1,4 bis [4 (N,N' diphenylamino)phenylvinyl] benzene = L78, and an n-type layer of 5,10,15,20-tetra(4-pyrydil)21H,23H-porphyne = TPyP. Transparent conductor films of Al-doped ZnO (AZO) with high transparency, >90% for wavelengths > 400 nm, and low resistivity, between 6.9 × 10−4 Ω·cm and 23 × 10−4 Ω·cm, were deposited by pulsed laser deposition on flexible substrates of polyethylene terephthalate (PET). The properties of the heterostructures based on oligomers and zinc phthalocyanine (ZnPc) were compared, emphasizing the effect of the surface morphology. The measurements revealed a good absorption in the visible range of the PET/AZO/arylenevinylene oligomer/TPyP heterostructures and a typical injection contact behavior with linear (ZnPc, L78) or non-linear (L13) J-V characteristics in the dark, at voltages < 0.4 V. The heterostructure PET/AZO/L78/TPyP/Al showed a current density of ~1 mA/cm2 at a voltage of 0.3 V. The correlation between the roughness exponent, evaluated from the height-height correlation function, grain shape, and electrical behavior was analyzed. Consequently, the oligomer based on triphenylamine could be a promising replacement of donor ZnPc in flexible electronic applications. [ABSTRACT FROM AUTHOR]

The dependence of surface potential value on the particle size of micro- and meso-fractions for powdered ZnS:Mn obtained using self-propagating high-temperature synthesis has been investigated. Rather good agreement of model representations for the change in the value of surface potential for the particle with its size changed due to overlapping the space charge regions from opposite surfaces within the range ~ 1 ≤ R/Leff ≤ ~ 2.2 (R, particle radius; Leff, screening length) with experimental data obtained using the method of Kelvin probe microscopy has been shown. The value of Leff for ZnS:Mn particles is estimated as approximately 30 nm. [ABSTRACT FROM AUTHOR]