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15 pages, 4099 KiB

Open AccessArticle

The Cytotoxic Effectiveness of Thiourea-Reduced Graphene Oxide on Human Lung Cancer Cells and Fungi

by Babu Vimalanathan, J. Judith Vijaya, B. Carmel Jeeva Mary, Ruby Nirmala Mary, Mohamed Km, Ramasamy Jayavel, Rasha A. Abumousa and Mohamed Bououdina

Nanomaterials 2023, 13(1), 149; https://doi.org/10.3390/nano13010149 - 28 Dec 2022

Cited by 5 | Viewed by 1449

Abstract

This study demonstrated the effective reduction of graphene oxide (GO) by employing thiourea as a reducing and stabilizing agent. Two fungi (Aspergillus flavus and Aspergillus fumigatus) were used for anti-fungal assay. Cell viability, cell cycle analysis, DNA fragmentation, and cell morphology [...] Read more.

This study demonstrated the effective reduction of graphene oxide (GO) by employing thiourea as a reducing and stabilizing agent. Two fungi (Aspergillus flavus and Aspergillus fumigatus) were used for anti-fungal assay. Cell viability, cell cycle analysis, DNA fragmentation, and cell morphology were assessed to determine the toxicity of thiourea-reduced graphene oxide (T-rGO) on human lung cancer cells. The results revealed that GO and T-rGO were hazardous to cells in a dose-dependent trend. The viability of both A. fumigatus and A. flavus was affected by GO and T-rGO. The reactive oxygen species produced by T-rGO caused the death of A. flavus and A. fumigatus cells. This study highlighted the effectiveness of T-rGO as an antifungal agent. In addition, T-rGO was found to be more harmful to cancer cells than GO. Thus, T-rGO manifested great potential in biological and biomedical applications. Full article

(This article belongs to the Special Issue Actual Problems of Solid State Physics: Nanomaterials and Nanotechnologies)

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11 pages, 2123 KiB

Open AccessArticle

A Cavity-Tailored Metal-Organic Tetrahedral Nanocage and Gas Adsorption Property

by Xin Jin, Hui Jiang, Yi Chen, Xin Han, Ken Sun, Linlin Shi, Xin-Qi Hao and Mao-Ping Song

Nanomaterials 2022, 12(24), 4402; https://doi.org/10.3390/nano12244402 - 09 Dec 2022

Cited by 2 | Viewed by 1568

Abstract

Porous organometallic nanomaterials are a new class of materials based on a three-dimensional structure. They have excellent applications in different fields, but their applications in gas storage and separation have not been fully developed. CO₂ adsorption storage and hydrocarbon separation has been [...] Read more.

Porous organometallic nanomaterials are a new class of materials based on a three-dimensional structure. They have excellent applications in different fields, but their applications in gas storage and separation have not been fully developed. CO₂ adsorption storage and hydrocarbon separation has been a challenging industrial problem. Several typical molecular adsorbents have been used to study the separation, but the problems of long-term stability, high selectivity and synthetic complexity of these adsorbents remain to be solved. Here, we have designed and synthesized tetrahedral metal supramolecular nanocage with custom cavities based on the unique rigid structure of triptycene derivatives. Using the unique discrete porous structure of tetrahedral metal nanocages, the gas adsorption and separation performance of the metal supramolecular nanocage was investigated. By analyzing the adsorption and desorption isotherms and the multi-component competitive adsorption curves, we noticed that the tetrahedral supramolecular nanocages had good CO₂ storage capacity and good separation capacity for C₂H₂/CO₂ and C₂H₂/N₂. All these indicate that porous organic metal nanomaterials are expected to be a new energy saving separation material. Full article

(This article belongs to the Special Issue Actual Problems of Solid State Physics: Nanomaterials and Nanotechnologies)

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14 pages, 2031 KiB

Open AccessArticle

Reconfigurable Radiation Angle Continuous Deflection of All-Dielectric Phase-Change V-Shaped Antenna

by Ping Tang, Qiao Tao, Shengde Liu, Jin Xiang, Liyun Zhong and Yuwen Qin

Nanomaterials 2022, 12(19), 3305; https://doi.org/10.3390/nano12193305 - 22 Sep 2022

Viewed by 1273

Abstract

All-dielectric optical antenna with multiple Mie modes and lower inherent ohmic loss can achieve high efficiency of light manipulation. However, the silicon-based optical antenna is not reconfigurable for specific scenarios. The refractive index of optical phase-change materials can be reconfigured under stimulus, and [...] Read more.

All-dielectric optical antenna with multiple Mie modes and lower inherent ohmic loss can achieve high efficiency of light manipulation. However, the silicon-based optical antenna is not reconfigurable for specific scenarios. The refractive index of optical phase-change materials can be reconfigured under stimulus, and this singular behavior makes it a good candidate for making reconfigurable passive optical devices. Here, the optical radiation characteristics of the V-shaped phase-change antenna are investigated theoretically. The results show that with increasing crystallinity, the maximum radiation direction of the V-shaped phase-change antenna can be continuously deflected by 90°. The exact multipole decomposition analysis reveals that the modulus and interference phase difference of the main multipole moments change with the crystallinity, resulting in a continuous deflection of the maximum radiation direction. Thus, the power ratio in the two vertical radiation directions can be monotonically reversed from −12 to 7 dB between 20% and 80% crystallinity. The V-shaped phase-change antenna exhibits the potential to act as the basic structural unit to construct a reconfigurable passive spatial angular power splitter or wavelength multiplexer. The mechanism analysis of radiation directivity involving the modulus and interference phase difference of the multipole moments will provide a reference for the design and optimization of the phase-change antenna. Full article

(This article belongs to the Special Issue Actual Problems of Solid State Physics: Nanomaterials and Nanotechnologies)

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18 pages, 9315 KiB

Open AccessArticle

The Interrelation of Synthesis Conditions and Wettability Properties of the Porous Anodic Alumina Membranes

by Daria I. Tishkevich, Alla I. Vorobjova, Anastasia A. Bondaruk, Elena S. Dashkevich, Dmitry L. Shimanovich, Ihar U. Razanau, Tatiana I. Zubar, Dmitry V. Yakimchuk, Mengge G. Dong, M. I. Sayyed, Hamoud H. Somaily, Denis A. Vinnik, Maxim V. Silibin, Sergei V. Trukhanov, Valery M. Fedosyuk and Alex V. Trukhanov

Nanomaterials 2022, 12(14), 2382; https://doi.org/10.3390/nano12142382 - 12 Jul 2022

Cited by 14 | Viewed by 1695

Abstract

The results of studies on the wettability properties and preparation of porous anodic alumina (PAA) membranes with a 3.3 ± 0.2 μm thickness and a variety of pore sizes are presented in this article. The wettability feature results, as well as the fabrication [...] Read more.

The results of studies on the wettability properties and preparation of porous anodic alumina (PAA) membranes with a 3.3 ± 0.2 μm thickness and a variety of pore sizes are presented in this article. The wettability feature results, as well as the fabrication processing characteristics and morphology, are presented. The microstructure effect of these surfaces on wettability properties is analyzed in comparison to outer PAA surfaces. The interfacial contact angle was measured for amorphous PAA membranes as-fabricated and after a modification technique (pore widening), with pore sizes ranging from 20 to 130 nm. Different surface morphologies of such alumina can be obtained by adjusting synthesis conditions, which allows the surface properties to change from hydrophilic (contact angle is approximately 13°) to hydrophobic (contact angle is 100°). This research could propose a new method for designing functional surfaces with tunable wettability. The potential applications of ordinary alumina as multifunctional films are demonstrated. Full article

(This article belongs to the Special Issue Actual Problems of Solid State Physics: Nanomaterials and Nanotechnologies)

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19 pages, 3915 KiB

Open AccessArticle

Structural Study of Nano-Clay and Its Effectiveness in Radiation Protection against X-rays

by Elfahem Sakher, Billel Smili, Mohamed Bououdina and Stefano Bellucci

Nanomaterials 2022, 12(14), 2332; https://doi.org/10.3390/nano12142332 - 07 Jul 2022

Cited by 1 | Viewed by 1794

Abstract

With the increasing applications of nuclear technology, radiation protection has become very important especially for the environment and the personnel close to radiation sources. Natural clays can be used potentially for shielding the X-ray radiations. In this study, the correlation between structural parameters [...] Read more.

With the increasing applications of nuclear technology, radiation protection has become very important especially for the environment and the personnel close to radiation sources. Natural clays can be used potentially for shielding the X-ray radiations. In this study, the correlation between structural parameters and radiation shielding performance of natural clay extracted from Algerian Sahara (Adrar, Reggan, and Timimoune) was investigated. Phase composition and structural parameters (lattice parameters, average crystallite size, and microstrain) were determined by the Rietveld refinements of X-ray diffraction patterns in the frame of HighScore Plus software. The obtained results showed that the studied clays are nanocrystalline (nano-clay) since the calculated crystallite size was ≈3 nm for the feldspar phase. FTIR spectra confirmed the presence of all phases already detected by XRD analysis besides Biotite (around the band at 3558 cm⁻¹). The remaining bands corresponded to absorbed and adsorbed water (3432 cm⁻¹ and 1629 cm⁻¹, respectively) and atmospheric CO₂ (2356 cm⁻¹). The shielding properties (mass absorption coefficient—µ/ρ and radiative attenuation rate—RA) for (green-yellow, green, and red) clays of Adrar, (red, white, and white-red) clays of Reggan, and red clay of Timimoune at same energy level were examined. The results of clay samples were compared with each other. The obtained results indicated that the green clay of Adrar exhibited the superior radiation shielding, i.e., 99.8% and 243.4 cm²/g for radiative attenuation rate and mass absorption coefficient, respectively. Full article

(This article belongs to the Special Issue Actual Problems of Solid State Physics: Nanomaterials and Nanotechnologies)

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9 pages, 10589 KiB

Open AccessArticle

Ion-Beam Synthesis of Gallium Oxide Nanocrystals in a SiO₂/Si Dielectric Matrix

by Dmitry S. Korolev, Kristina S. Matyunina, Alena A. Nikolskaya, Ruslan N. Kriukov, Alexey V. Nezhdanov, Alexey I. Belov, Alexey N. Mikhaylov, Artem A. Sushkov, Dmitry A. Pavlov, Pavel A. Yunin, Mikhail N. Drozdov and David I. Tetelbaum

Nanomaterials 2022, 12(11), 1840; https://doi.org/10.3390/nano12111840 - 27 May 2022

Cited by 3 | Viewed by 1585

Abstract

A new method for creating nanomaterials based on gallium oxide by ion-beam synthesis of nanocrystals of this compound in a SiO₂/Si dielectric matrix has been proposed. The influence of the order of irradiation with ions of phase-forming elements (gallium and oxygen) [...] Read more.

A new method for creating nanomaterials based on gallium oxide by ion-beam synthesis of nanocrystals of this compound in a SiO₂/Si dielectric matrix has been proposed. The influence of the order of irradiation with ions of phase-forming elements (gallium and oxygen) on the chemical composition of implanted layers is reported. The separation of gallium profiles in the elemental and oxidized states is shown, even in the absence of post-implantation annealing. As a result of annealing, blue photoluminescence, associated with the recombination of donor–acceptor pairs (DAP) in Ga₂O₃ nanocrystals, appears in the spectrum. The structural characterization by transmission electron microscopy confirms the formation of β-Ga₂O₃ nanocrystals. The obtained results open up the possibility of using nanocrystalline gallium oxide inclusions in traditional CMOS technology. Full article

(This article belongs to the Special Issue Actual Problems of Solid State Physics: Nanomaterials and Nanotechnologies)

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9 pages, 1825 KiB

Open AccessArticle

Structural and Magnetic Phase Transitions in BiFe_{1 − x}Mn_xO₃ Solid Solution Driven by Temperature

by Dmitry V. Karpinsky, Maxim V. Silibin, Siarhei I. Latushka, Dmitry V. Zhaludkevich, Vadim V. Sikolenko, Hanan Al-Ghamdi, Aljawhara H. Almuqrin, M. I. Sayyed and Alexei A. Belik

Nanomaterials 2022, 12(9), 1565; https://doi.org/10.3390/nano12091565 - 05 May 2022

Cited by 4 | Viewed by 1354

Abstract

The crystal structure and magnetic state of the (1 − x)BiFeO₃-(x)BiMnO₃ solid solution has been analyzed by X-ray diffraction using lab-based and synchrotron radiation facilities, magnetization measurements, differential thermal analysis, and differential scanning calorimetry. Dopant concentration increases lead to the [...] Read more.

The crystal structure and magnetic state of the (1 − x)BiFeO₃-(x)BiMnO₃ solid solution has been analyzed by X-ray diffraction using lab-based and synchrotron radiation facilities, magnetization measurements, differential thermal analysis, and differential scanning calorimetry. Dopant concentration increases lead to the room-temperature structural transitions from the polar-active rhombohedral phase to the antipolar orthorhombic phase, and then to the monoclinic phase accompanied by the formation of two-phase regions consisting of the adjacent structural phases in the concentration ranges 0.25 < x₁ < 0.30 and 0.50 ≤ x₂ < 0.65, respectively. The accompanied changes in the magnetic structure refer to the magnetic transitions from the modulated antiferromagnetic structure to the non-colinear antiferromagnetic structure, and then to the orbitally ordered ferromagnetic structure. The compounds with a two-phase structural state at room temperature are characterized by irreversible temperature-driven structural transitions, which favor the stabilization of high-temperature structural phases. The magnetic structure of the compounds also exhibits an irreversible temperature-induced transition, resulting in an increase of the contribution from the magnetic phase associated with the high-temperature structural phase. The relationship between the structural parameters and the magnetic state of the compounds with a metastable structure is studied and discussed depending on the chemical composition and heating prehistory. Full article

(This article belongs to the Special Issue Actual Problems of Solid State Physics: Nanomaterials and Nanotechnologies)

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17 pages, 3960 KiB

Open AccessArticle

A Study of Ta₂O₅ Nanopillars with Ni Tips Prepared by Porous Anodic Alumina Through-Mask Anodization

by Alla I. Vorobjova, Daria I. Tishkevich, Elena A. Outkina, Dmitry L. Shimanovich, Ihar U. Razanau, Tatiana I. Zubar, Anastasia A. Bondaruk, Ekaterina K. Zheleznova, Mengge Dong, Dalal A. Aloraini, M. I. Sayyed, Aljawhara H. Almuqrin, Maxim V. Silibin, Sergey V. Trukhanov and Alex V. Trukhanov

Nanomaterials 2022, 12(8), 1344; https://doi.org/10.3390/nano12081344 - 14 Apr 2022

Cited by 18 | Viewed by 2314

Abstract

The paper discusses the formation of Ta₂O₅ pillars with Ni tips during thin porous anodic alumina through-mask anodization on Si/SiO₂ substrates. The tantalum nanopillars were formed through porous masks in electrolytes of phosphoric and oxalic acid. The Ni tips [...] Read more.

The paper discusses the formation of Ta₂O₅ pillars with Ni tips during thin porous anodic alumina through-mask anodization on Si/SiO₂ substrates. The tantalum nanopillars were formed through porous masks in electrolytes of phosphoric and oxalic acid. The Ni tips on the Ta₂O₅ pillars were formed via vacuum evaporation through the porous mask. The morphology, structure, and magnetic properties at 4.2 and 300 K of the Ta₂O₅ nanopillars with Ni tips have been studied using scanning electron microscopy, X-ray diffraction, and vibrating sample magnetometry. The main mechanism of the formation of the Ta₂O₅ pillars during through-mask anodization was revealed. The superparamagnetic behavior of the magnetic hysteresis loop of the Ta₂O₅ nanopillars with Ni tips was observed. Such nanostructures can be used to develop novel functional nanomaterials for magnetic, electronic, biomedical, and optical nano-scale devices. Full article

(This article belongs to the Special Issue Actual Problems of Solid State Physics: Nanomaterials and Nanotechnologies)

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18 pages, 5224 KiB

Open AccessArticle

Creation and Magnetic Study of Ferrites with Magnetoplumbite Structure Multisubstituted by Al³⁺, Cr³⁺, Ga³⁺, and In³⁺ Cations

by Vladimir E. Zhivulin, Daria P. Sherstyuk, Olga V. Zaitseva, Natalia A. Cherkasova, Denis A. Vinnik, Sergey V. Taskaev, Evgeny A. Trofimov, Sergei V. Trukhanov, Siarhei I. Latushka, Daria I. Tishkevich, Tatiana I. Zubar and Alex V. Trukhanov

Nanomaterials 2022, 12(8), 1306; https://doi.org/10.3390/nano12081306 - 11 Apr 2022

Cited by 18 | Viewed by 1637

Abstract

Multisubstituted barium ferrites with a magnetoplumbite structure were obtained by the method of solid-phase reactions with ferritization and pre-firing. Three-charged, mainly diamagnetic cations Al³⁺, Cr³⁺, Ga³⁺, and In³⁺ were chosen as substituents for the Fe³⁺ [...] Read more.

Multisubstituted barium ferrites with a magnetoplumbite structure were obtained by the method of solid-phase reactions with ferritization and pre-firing. Three-charged, mainly diamagnetic cations Al³⁺, Cr³⁺, Ga³⁺, and In³⁺ were chosen as substituents for the Fe³⁺ iron cations, the proportion of which in solid solutions did not exceed 50%. The values of the configurational mixing entropy were calculated for all the compositions. A slight deviation of the chemical composition of the obtained solid solutions from the nominal value was established by the energy-dispersive X-ray spectroscopy method. The phase purity and values of the unit cell parameters were refined from X-ray scattering data using full-profile analysis in the Rietveld method. A non-monotonic behavior of the unit cell parameters as a function of the B-sub-lattice average ionic radius of the magnetoplumbite structure was found. A minimum unit cell volume of ~667.15 Å³ was found for the composition BaFe_6.11Al_1.56Cr_2.17Ga_2.16O₁₉ with a B-sub-lattice average ionic radius of ~7.449 Å. The average crystallite size varied within 5.5–6.5 μm. The temperature and field dependencies of the magnetization have been measured. The values of the saturation magnetization, residual magnetization, hysteresis loop squareness, and coercivity at 50 K and 300 K were extracted from the experimental data. Using the Law of Approach to Saturation, the magnetic crystallographic anisotropy coefficient and anisotropy field were calculated. Multisubstitution leads to a significant decrease in such magnetic parameters as the magnetic ordering temperature and spontaneous magnetization at both temperatures. The maximum magnetic ordering temperature of ~297.7 K was found for the composition BaFe_5.84Ga_6.19O₁₉ with a B-sub-lattice average ionic radius of ~7.586 Å in a field of 500 Oe. A maximum saturation magnetization of ~24.7 emu/g was found for the composition BaFe_5.84Ga_6.19O₁₉ with a B-sub-lattice average ionic radius of ~7.586 Å at 50 K. A maximum hysteresis loop squareness of ~0.72 was found for the composition BaFe_6.11Al_1.56Cr_2.17Ga_2.16O₁₉ with an average ionic radius of ~7.449 Å at 50 K. A maximum magnetic crystallographic anisotropy coefficient of ~2.09 × 10⁵ Erg/g was found for the composition BaFe_6.19Al_1.25Cr_1.57Ga_1.74In_1.26O₁₉ with a B-sub-lattice average ionic radius of ~7.706 Å at 50 K. The frustrated magnetic state including the nano-sized clusters with an average diameter in the range of 50–200 nm was established from the results of measuring the ZFC and FC temperature magnetizations. The interpretation of the obtained experimental data is carried out taking into account the increased stability of high-entropy phases and regular changes in the intensity of the Fe³⁺(Al³⁺, Cr³⁺, Ga³⁺, In³⁺)–O²⁻–Fe³⁺(Al³⁺, Cr³⁺, Ga³⁺, In³⁺) indirect superexchange interactions as a result of magnetic dilution of the iron sub-lattice in the magnetoplumbite structure. Full article

(This article belongs to the Special Issue Actual Problems of Solid State Physics: Nanomaterials and Nanotechnologies)

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28 pages, 35632 KiB

Open AccessArticle

Structure, Morphology and Electrical/Magnetic Properties of Ni-Mg Nano-Ferrites from a New Perspective

by Maha Mostafa, Oday Saleh, Ahmed Maher Henaish, Samir Ali Abd El-Kaream, Ryad Ghazy, Osama M. Hemeda, Ali M. Dorgham, Hanan Al-Ghamdi, Aljawhara H. Almuqrin, M. I. Sayyed, Sergei V. Trukhanov, Ekaterina L. Trukhanova, Alex V. Trukhanov, Di Zhou and Moustafa A. Darwish

Nanomaterials 2022, 12(7), 1045; https://doi.org/10.3390/nano12071045 - 22 Mar 2022

Cited by 41 | Viewed by 2788

Abstract

Using the auto combustion flash method,

{Ni}_{1 - x}^{+ 2} {Mg}_{x}^{+ 2} {Fe}_{2}^{+ 3} O_{4}

(x = 0, 0.2, 0.6, 0.8 and 1) nano-ferrites were synthesized. All samples were thermally treated at 973 K for 3 [...] Read more.

Using the auto combustion flash method,

{Ni}_{1 - x}^{+ 2} {Mg}_{x}^{+ 2} {Fe}_{2}^{+ 3} O_{4}

(x = 0, 0.2, 0.6, 0.8 and 1) nano-ferrites were synthesized. All samples were thermally treated at 973 K for 3 h. The structural analysis for the synthesized samples was performed using XRD, high-resolution transmission electron microscopy (HRTEM), and FTIR. Scanning electron microscopy (SEM) was undertaken to explore the surface morphology of all the samples. The thermal stability of these samples was investigated using thermogravimetric analysis (TGA). XRD data show the presence of a single spinel phase for all the prepared samples. The intensity of the principal peak of the spinel phase decreases as Mg content increases, showing that Mg delays crystallinity. The Mg content raised the average grain size (D) from 0.084 μm to 0.1365 μm. TGA shows two stages of weight loss variation. The vibrating sample magnetometer (VSM) measurement shows that magnetic parameters, such as initial permeability (μ_i) and saturation magnetization (M_s), decay with rising Mg content. The permeability and magnetic anisotropy at different frequencies and temperatures were studied to show the samples’ magnetic behavior and determine the Curie temperature (T_C), which depends on the internal structure. The electrical resistivity behavior shows the semi-conductivity trend of the samples. Finally, the dielectric constant increases sharply at high temperatures, explained by the increased mobility of charge carriers, and decreases with increasing frequency. Full article

(This article belongs to the Special Issue Actual Problems of Solid State Physics: Nanomaterials and Nanotechnologies)

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12 pages, 4543 KiB

Open AccessFeature PaperArticle

Impact of the Nanocarbon on Magnetic and Electrodynamic Properties of the Ferrite/Polymer Composites

by Alex V. Trukhanov, Daria I. Tishkevich, Svetlana V. Podgornaya, Egor Kaniukov, Moustafa A. Darwish, Tatiana I. Zubar, Andrey V. Timofeev, Ekaterina L. Trukhanova, Vladimir G. Kostishin and Sergei V. Trukhanov

Nanomaterials 2022, 12(5), 868; https://doi.org/10.3390/nano12050868 - 04 Mar 2022

Cited by 74 | Viewed by 2375

Abstract

Binary and ternary composites (CM) based on M-type hexaferrite (HF), polymer matrix (PVDF) and carbon nanomaterials (quasi-one-dimensional carbon nanotubes—CNT and quasi-two-dimensional carbon nanoflakes—CNF) were prepared and investigated for establishing the impact of the different nanosized carbon on magnetic and electrodynamic properties. The ratio [...] Read more.

Binary and ternary composites (CM) based on M-type hexaferrite (HF), polymer matrix (PVDF) and carbon nanomaterials (quasi-one-dimensional carbon nanotubes—CNT and quasi-two-dimensional carbon nanoflakes—CNF) were prepared and investigated for establishing the impact of the different nanosized carbon on magnetic and electrodynamic properties. The ratio between HF and PVDF in HF + PVDF composite was fixed (85 wt% HF and 15 wt% PVDF). The concentration of CNT and CNF in CM was fixed (5 wt% from total HF + PVDF weight). The phase composition and microstructural features were investigated using XRD and SEM, respectively. It was observed that CM contains single-phase HF, γ- and β-PVDF and carbon nanomaterials. Thus, we produced composites that consist of mixed different phases (organic insulator matrix—PDVF; functional magnetic fillers—HF and highly electroconductive additives—CNT/CNF) in the required ratio. VSM data demonstrate that the main contribution in main magnetic characteristics belongs to magnetic fillers (HF). The principal difference in magnetic and electrodynamic properties was shown for CNT- and CNF-based composites. That confirms that the shape of nanosized carbon nanomaterials impact on physical properties of the ternary composited-based magnetic fillers in polymer dielectric matrix. Full article

(This article belongs to the Special Issue Actual Problems of Solid State Physics: Nanomaterials and Nanotechnologies)

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6 pages, 1327 KiB

Open AccessArticle

Dimension-Dependent Phenomenological Model of Excitonic Electric Dipole in InGaAs Quantum Dots

by Petr Steindl and Petr Klenovský

Nanomaterials 2022, 12(4), 719; https://doi.org/10.3390/nano12040719 - 21 Feb 2022

Cited by 2 | Viewed by 1462

Abstract

Permanent electric dipole is a key property for effective control of semiconductor quantum-dot-based sources of quantum light. For theoretical prediction of that, complex geometry-dependent quantum simulations are necessary. Here, we use

k \cdot p

simulations of exciton transition in InGaAs quantum dots to [...] Read more.

Permanent electric dipole is a key property for effective control of semiconductor quantum-dot-based sources of quantum light. For theoretical prediction of that, complex geometry-dependent quantum simulations are necessary. Here, we use

k \cdot p

simulations of exciton transition in InGaAs quantum dots to derive a simple geometry-dependent analytical model of dipole. Our model, discussed here, enables reasonably good estimation of the electric dipole, caused in quantum dot by the elastic strain, including an externally induced one. Due to its apparent simplicity, not necessitating elaborate and time-consuming simulations, it might after experimental verification serve as a preferred choice for experimentalists enabling them to make quick estimates of built-in and induced electric dipole in quantum dots. Full article

(This article belongs to the Special Issue Actual Problems of Solid State Physics: Nanomaterials and Nanotechnologies)

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15 pages, 4650 KiB

Open AccessArticle

Insights into Sorption–Mineralization Mechanism for Sustainable Granular Composite of MgO-CaO-Al₂O₃-SiO₂-CO₂ Based on Nanosized Adsorption Centers and Its Effect on Aqueous Cu(II) Removal

by Alla G. Morozova, Tatiana M. Lonzinger, Vadim A. Skotnikov, Gennady G. Mikhailov, Yury Kapelyushin, Mayeen Uddin Khandaker, Amal Alqahtani, D. A. Bradley, M. I. Sayyed, Daria I. Tishkevich, Denis A. Vinnik and Alex V. Trukhanov

Nanomaterials 2022, 12(1), 116; https://doi.org/10.3390/nano12010116 - 30 Dec 2021

Cited by 3 | Viewed by 1675

Abstract

Although copper is needed for living organisms at low concentrations, it is one of the pollutants that should be monitored along with other heavy metals. A novel and sustainable composite mineralizing sorbent based on MgO-CaO-Al₂O₃-SiO₂-CO₂ with [...] Read more.

Although copper is needed for living organisms at low concentrations, it is one of the pollutants that should be monitored along with other heavy metals. A novel and sustainable composite mineralizing sorbent based on MgO-CaO-Al₂O₃-SiO₂-CO₂ with nanosized adsorption centers was synthesized using natural calcium–magnesium carbonates and clay aluminosilicates for copper sorption. An organometallic modifier was added as a temporary binder and a source of inovalent ions participating in the reactions of defect formation and activated sintering. The sorbent-mineralizer samples of specified composition and properties showed irreversible sorption of Cu²⁺ ions by the ion exchange reactions Ca²⁺ ↔ Cu²⁺ and Mg²⁺ ↔ Cu²⁺. The topochemical reactions of the ion exchange 2OH⁻ → CO₃²⁻, 2OH⁻ → SO₄²⁻ and CO₃²⁻ → SO₄²⁻ occurred at the surface with formation of the mixed calcium–copper carbonates and sulfates structurally connected with aluminosilicate matrix. The reverse migration of ions to the environment is blocked by the subsequent mineralization of the newly formed interconnected aluminosilicate and carbonate structures. Full article

(This article belongs to the Special Issue Actual Problems of Solid State Physics: Nanomaterials and Nanotechnologies)

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Review

Jump to: Research

32 pages, 5125 KiB

Open AccessFeature PaperReview

Environmental Implications Associated with the Development of Nanotechnology: From Synthesis to Disposal

by Otávio Augusto L. dos Santos, Bianca Pizzorno Backx, Rasha A. Abumousa and Mohamed Bououdina

Nanomaterials 2022, 12(23), 4319; https://doi.org/10.3390/nano12234319 - 05 Dec 2022

Cited by 1 | Viewed by 1635

Abstract

Nanotechnology remains under continuous development. The unique, fascinating, and tunable properties of nanomaterials make them interesting for diverse applications in different fields such as medicine, agriculture, and remediation. However, knowledge about the risks associated with nanomaterials is still poorly known and presents variable [...] Read more.

Nanotechnology remains under continuous development. The unique, fascinating, and tunable properties of nanomaterials make them interesting for diverse applications in different fields such as medicine, agriculture, and remediation. However, knowledge about the risks associated with nanomaterials is still poorly known and presents variable results. Furthermore, the interaction of nanomaterials with biological systems and the environment still needs to be clarified. Moreover, some issues such as toxicity, bioaccumulation, and physicochemical transformations are found to be dependent on several factors such as size, capping agent, and shape, making the comparisons even more complex. This review presents a comprehensive discussion about the consequences of the use and development of nanomaterials regarding their potential risks to the environment as well as human and animal health. For this purpose, we reviewed the entire production chain from manufacturing, product development, applications, and even product disposal to raise the important implications at each stage. In addition, we present the recent developments in terms of risk management and the recycling of nanomaterials. Furthermore, the advances and limitations in the legislation and characterization of nanomaterials are also discussed. Full article

(This article belongs to the Special Issue Actual Problems of Solid State Physics: Nanomaterials and Nanotechnologies)

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