Publications by authors named "Mariusz Stefanski"

Inorganic halide perovskites have been the subject of intensive research for their unique properties. Most current research focuses on halide ion exchange to modify the luminescence band gap and optical features. They are obtained mainly in colloids or thin layers, resulting in small grains with a narrow distribution.

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Ceramic phosphors have high thermal conductivity and high thermal stability, showing great potential for use in laser lighting. However, it is difficult to further improve the forward efficiency in transmissive mode because of the arbitrarily emitting ceramic phosphors and light loss by secondary optical components. Here, an effective design of rod-shaped LuAG:Ce transparent ceramics was proposed, and the silicone encapsulated ceramic-based devices could operate stably under 3.

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This paper presents the synthesis and characterization of graphene-polymer composites, focusing on their mechanical and antibacterial properties. Graphene flakes were obtained via an electrochemical method and integrated into polyamide 6 (PA6) matrices using melt intercalation. Various characterization techniques confirmed the quality of the graphene flakes, including X-ray diffraction (XRD), Raman spectroscopy, and infrared (IR) spectroscopy, as well as scanning and transmission electron microscopy (SEM and TEM) imaging.

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In this study, graphene flakes were obtained using an electrolytic method and characterized using X-ray diffraction (XRD), Raman and FTIR spectroscopy, scanning and transmission electron microscopy (SEM/TEM). Graphene-based composites with varying concentrations of 0.5%, 1% and 3% by weight were prepared with acrylic paint, enamel and varnish matrices.

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This paper demonstrates the generation of broadband emission in the visible and infrared ranges induced by a concentrated beam of infrared radiation from CsPbBr ceramics doped with Yb ions. The sample was obtained by the conventional solid-state reaction method, and XRD measurements confirmed the phase purity of the material crystallizing in the orthorhombic system. Spectroscopic measurements required further sample preparation in the form of ceramics using a high-pressure press.

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Graphene nanoplatelets (GNPs) were prepared using the electrolytic exfoliation method on graphite foil in an ammonium sulfate solution. A series of experiments were conducted in order to optimize the production of the flakes by varying the pH of the solution, applied voltage and current, duration of electrolysis, temperature in the electrolytic system, and type and duration of the ultrasound interaction. The quality of the produced graphene nanoplatelets was analyzed using X-ray diffraction, Raman and IR spectroscopy, and TEM.

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Mono-substituted cage-like silsesquioxanes of the T-type can play the role of potential ligands in the coordination chemistry. In this paper, we report on imine derivatives as ligands for samarium, terbium, and erbium cations and discuss their efficient synthesis, crystal structures, and magnetic and optical properties. X-ray analysis of the lanthanide coordination entities [MCl(POSS)]·2THF [M = Er (), Tb (), Sm ()] showed that all three compounds crystallize in the same space group with similar lattice parameters.

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The synthesis and structural characteristics of nanocrystalline LaAlO perovskites doped with different concentrations of Nd ions are reported. Their excitation and Stokes emission spectra, in which significant concentration quenching was observed, were recorded and characterized. The measurements of anti-Stokes laser induced white emission (LIWE) spectra were also performed.

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The synthesis and investigation of the physicochemical properties of a novel one-dimensional (1D) hybrid organic-inorganic perovskitoid templated by the 1,1,1-trimethylhydrazinium (MeHy) cation are reported. (MeHy)[PbI] crystallizes in the hexagonal 6/ symmetry and undergoes two phase transitions (PTs) during heating (cooling) at 322 (320) and 207 (202) K. X-ray diffraction data and temperature-dependent vibrational studies show that the second-order PT to the high-temperature hexagonal 6/ phase is associated with a weak change in entropy and is related to weak structural changes and different confinement of cations in the available space.

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A new method of hydrogen generation from water, by irradiation with CW infrared laser diode of graphene scaffold immersed in solution, is reported. Hydrogen production was extremely efficient upon admixing NaCl into water. The efficiency of hydrogen production increased exponentially with laser power.

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In alkali metal and lanthanide coordination chemistry, triphenylsiloxides seem to be unduly underappreciated ligands. This is as surprising as that such substituents play a crucial role, among others, in stabilizing rare oxidation states of lanthanide ions, taking a part of intramolecular and molecular interactions stabilizing metal-oxygen cores and many others. This paper reports the synthesis and characterization of new lithium [Li(OSiPh)(THF)] (), and sodium [Na(OSiPh)] () species, which were later used in obtaining novel gadolinium [Gd(OSiPh)(THF)]·THF (), and erbium [Er(OSiPh)(THF)]·THF () configuration, it can result in res were determined for all - compounds, and in addition, IR, Raman, absorption spectroscopy studies were conducted for and lanthanide compounds.

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The measurements of laser induced emission (LIE) of a tungsten filament upon irradiation with the focused beam of a CW IR laser diode are reported. It was found that the emission occurred in visible and infrared range. The influence of the applied DC electric field significantly affected the intensity of LIE of the tungsten filament.

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Single crystals of a non-centrosymmetric and polar CsBiO(GeO) compound were grown from melt. This material was characterized by polarized Raman scattering at room temperature. The comparison to the polycrystalline IR and Raman spectra has been made and assignment of all observed modes to the respective vibrations and their symmetry has been proposed.

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The Stokes and anti-Stokes emission spectra generated from Sr2CeO4/graphene flake composites were investigated. The excitation and emission spectra, decay profiles and quantum efficiency of the studied materials were collected. It was found that the addition of graphene flakes (GFs) significantly affects spectroscopic properties.

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Introduction: Pulmonary neuroendocrine cells (PNEC) are present in the normal lungs with the incidence of 1 in 2500 epithelial cells. They usually proliferate in the presence of reactive processes related to inflammation and fibrosis of the lung parenchyma. The division of pulmonary neuroendocrine cell hyperplasia proposed by Travis et al.

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