Understanding the physical and chemical properties of nanolayers is crucial for developing new and advanced nanomaterials. Irradiation with low‐energy, highly charged ions allows the modification of materials, creating novel surface structure features. The nanolayers can be characterized using surface‐sensitive techniques such as X‐ray reflectometry or grazing incidence X‐ray fluorescence (GIXRF). GIXRF is a non‐destructive spectroscopy method for analyzing elemental depth distributions in thin layer structures. The aim of this work was to analyze titanium (Ti) and titanium dioxide (TiO 2 ) nanolayers deposited on Si substrate, unmodified and irradiated with low‐energy (100 of keV) highly charged Xe q+ ( q = 25, 30, 35), and to determine the influence of this process on the morphology of irradiated surfaces. The nanolayers were irradiated at the Kielce EBIS facility. The GIXRF measurements were performed at Elettra Synchrotron XRF beamline. The results obtained from the GIXRF method show that the intensity changes of analyzed fluorescence lines depend on the thickness of nanolayers and the ion charge states.
Efficient removal of nitrogen oxides (NO x ) from urban air is a pressing environmental need. Here, Ni‐doped SnS 2 nanoflowers are synthesized via a microwave‐assisted solvothermal method and their visible‐light‐driven NO x abatement performance is evaluated. X‐ray diffraction and Raman confirm phase‐pure hexagonal SnS 2 , while X‐ray photoelectron spectroscopy verifies successful Ni 2 ⁺ incorporation without secondary phases. Ni doping slightly distorts the marigold flower‐like morphology observed in pristine SnS 2 and narrows the bandgap (UV–vis), enhancing visible‐light absorption and charge separation. Photoluminescence spectra reveal suppressed carrier recombination, with 5 wt% Ni‐doped SnS 2 showing the lowest emission intensity. Photocatalytic tests demonstrate that this composition achieves the highest NO x removal efficiency (14.2%) within 60 min, 1.6× higher than pristine SnS 2 , while maintaining 70% activity after ten cycles. Theoretical calculations reveal Ni‐3 d /S‐p hybridization and the introduction of mid‐gap states, which lower the optical transition threshold and support the experimentally observed bandgap narrowing and enhanced light harvesting. A mechanism involving Ni‐induced electron trapping and reactive oxygen species generation is proposed to explain the enhanced activity. This work establishes Ni doping as an effective strategy to tailor the structural, optical, and electronic properties of SnS 2 , delivering a low‐cost, stable, and highly active photocatalyst for sustainable NO x mitigation.
The electrical response of vibrating, electrostatically driven microelectromechanical and nanoelectromechanical system (MEMS and NEMS) devices was measured electrically using impedance spectroscopy. A physical model of this structure was elaborated, allowing us to predict the electrical response based on the dimensions and mechanical properties of the structure as well as the measurement conditions. This result was correlated with the results of the electrical equivalent circuit model. The physical model predicted that the magnitude of the electrical response is inversely proportional to the distance between the electrodes to the power of 4. Such a strong dependence was verified experimentally using a vibrating electrostatically driven MEMS operating in vacuum. The verified physical model is suitable for optimization of MEMS structures designed for electrical detection of vibrations.
NanoParticle Direct Doping (NPDD) (Gajc and Pawlak, Adv Funct Mater 23:3443, 2013) is a method developed in the Institute of Electronic Materials Technology in Warsaw that allows fabrication of volumetric composites based on low-melting-point glass matrices doped with various kinds of nanoparticles (NPs), including metallic plasmonic NPs and Quantum Dots (QDs). It is based on a Micro-Pulling down method, in which dry powders of the matrix and dopants are mixed together, heated until the matrix melts and then pulled in a form of a rod. Here we show that it is possible to obtain composite material doped with silver NPs with diameter of 20 nm, based on a sodium borophosphate dielectric glass (NBP), which is transparent over wide range of wavelengths and exhibits melting temperature of ca. 750 °C (Gajc and Pawlak, Adv Funct Mater 23:3443, 2013). It results in Localized Surface Plasmon Resonance (LSPR) peak visible on the absorbance spectrum of the material with maximum at 405 nm. It is also possible to co-dope the composite with QDs. Addition of Ag NPs results in the enhancement of the 510 nm excitonic emission from CdTe QDs compared to the material doped only with QDs. The NPDD method allows us to combine different types of NPs. Even after co-doping simultaneously with hydrophilic CdTe QDs (λem = 730 nm) and hydrophobic, core-shell CdSe/ZnS QDs (λem = 530 nm) material exhibits dual-wavelength photoluminescence (Nowaczynski and Pawlak Part Part Syst Charact 36:1800124, 2018). This versatility of the method can potentially allow us to construct a material doped with Ag NPs, QDs and rare-earth ions, especially Pr3+ to achieve narrowband Pr luminescence with laser diode excitation at wavelengths that are not absorbed well by the Pr itself. However, quality and homogeneity of composites has to be improved, which can be achieved by modification of the initial powder preparation process, like QDs dispersion in toluene prior to mixing with glass powder (Fig. 23.1).
Electromagnetic fields interacting with microscopic structural features in a composite material provide emerging optical properties that surpass those offered by the individual components. However, composite materials can be generally lossy due to the scattering effects induced by inhomogeneities at the interfaces between different compounds. To overcome such problems, complicated and costly manufacturing procedures, such as top-down approaches, are generally required. In contrast, here ZnO-ZnWO4 eutectic self-organized composites grown by the micropulling method are considered, displaying sharp and strongly polarized transmission at 397 nm. Such an optical response is notable because it is not observed in either ZnO or ZnWO4 single crystals. The optical response is due to the refractive index matching of the two constituents, which self-organize into ordered structures via a micropulling down method. The optical behavior reported here can directly lead to applications, such as tunable narrowband filters with bandpass of 3 nm and polarizers, paving the way to a new self-organization route for manufacturing optical components.
