Nanomaterials

3 pages, 748 KiB

Open AccessEditorial

Advances in Surface-Enhanced and Tip-Enhanced Raman Spectroscopy, Mapping and Methods Combined with Raman Spectroscopy for the Characterization of Perspective Carbon Nanomaterials

by Marianna V. Kharlamova

Nanomaterials 2023, 13(17), 2495; https://doi.org/10.3390/nano13172495 - 4 Sep 2023

Viewed by 3252

Abstract

Surface-enhanced Raman spectroscopy (SERS) is based on the effect of the plasmonic enhancement of intensity of the Raman scattering of molecules in cases when they are adsorbed on a substrate [...] Full article

(This article belongs to the Special Issue Advances in Spectroscopy of Carbon Nanomaterials: Methods and Applications)

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17 pages, 7263 KiB

Open AccessArticle

Functionalization of Fluorine on the Surface of SnO₂–Mg Nanocomposite as an Efficient Photocatalyst for Toxic Dye Degradation

by G. Velmurugan, R. Ganapathi Raman, P. Sivaprakash, A. Viji, Shin Hum Cho and Ikhyun Kim

Nanomaterials 2023, 13(17), 2494; https://doi.org/10.3390/nano13172494 - 4 Sep 2023

Cited by 16 | Viewed by 1446

Abstract

This work reports on the photocatalytic activity of tin oxide (SnO₂)-doped magnesium (Mg) and fluorine (F) nanoparticles for methyl orange and safranin dye degradation under sunlight irradiation. Nanocatalysis-induced dye degradation was examined using UV–visible spectroscopy and a pseudo-first-order kinetics model. The [...] Read more.

This work reports on the photocatalytic activity of tin oxide (SnO₂)-doped magnesium (Mg) and fluorine (F) nanoparticles for methyl orange and safranin dye degradation under sunlight irradiation. Nanocatalysis-induced dye degradation was examined using UV–visible spectroscopy and a pseudo-first-order kinetics model. The results indicate that the prepared nanoparticles exhibit superior photocatalytic activity, and the degradation of methyl orange (MO) dye is approximately 82%. In contrast, the degradation of safranin dye is 96% in the same time interval of 105 min. The calculated crystallite size of the SnO₂–Mg–F nanocomposite is 29.5 nm, which respects the particle size found in the DLS analysis with a tetragonal structure and spherical morphology affirmed. The optical characteristics were assessed, and their respective bandgap energies were determined to be 3.6 eV. The influence of F in Mg and SnO₂ is recognized with the XRD and FT-IR spectra of the prepared particles. Full article

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16 pages, 4979 KiB

Open AccessArticle

In Situ Fabrication of SnS₂/SnO₂ Heterostructures for Boosting Formaldehyde−Sensing Properties at Room Temperature

by Dan Meng, Zongsheng Xie, Mingyue Wang, Juhua Xu, Xiaoguang San, Jian Qi, Yue Zhang, Guosheng Wang and Quan Jin

Nanomaterials 2023, 13(17), 2493; https://doi.org/10.3390/nano13172493 - 4 Sep 2023

Cited by 9 | Viewed by 1524

Abstract

Formaldehyde, as a harmful gas produced by materials used for decorative purposes, has a serious impact on human health, and is also the focus and difficulty of indoor environmental polution prevention; hence, designing and developing gas sensors for the selective measurement of formaldehyde [...] Read more.

Formaldehyde, as a harmful gas produced by materials used for decorative purposes, has a serious impact on human health, and is also the focus and difficulty of indoor environmental polution prevention; hence, designing and developing gas sensors for the selective measurement of formaldehyde at room temperature is an urgent task. Herein, a series of SnS₂/SnO₂ composites with hollow spherical structures were prepared by a facile hydrothermal approach for the purpose of formaldehyde sensing at room temperature. These novel hierarchical structured SnS₂/SnO₂ composites−based gas sensors demonstrate remarkable selectivity towards formaldehyde within the concentration range of sub-ppm (0.1 ppm) to ppm (10 ppm) at room temperature. Notably, the SnS₂/SnO₂−2 sensor exhibits an exceptional formaldehyde-sensing performance, featuring an ultra-high response (1.93, 0.1 ppm and 17.51, 10 ppm), as well as good repeatability, long-term stability, and an outstanding theoretical detection limit. The superior sensing capabilities of the SnS₂/SnO₂ composites can be attributed to multiple factors, including enhanced formaldehyde adsorption, larger specific surface area and porosity of the hollow structure, as well as the synergistic interfacial incorporation of the SnS₂/SnO₂ heterojunction. Overall, the excellent gas sensing performance of SnS₂/SnO₂ hollow spheres has opened up a new way for their detection of trace formaldehyde at room temperature. Full article

(This article belongs to the Special Issue Nanostructured Materials in Gas Sensing Applications)

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Graphical abstract

10 pages, 2166 KiB

Open AccessArticle

Beaded CoSe₂-C Nanofibers for High-Performance Lithium–Sulfur Batteries

by Jing Xu, Juan Ao, Yonghui Xie, Yumei Zhou and Xinghui Wang

Nanomaterials 2023, 13(17), 2492; https://doi.org/10.3390/nano13172492 - 4 Sep 2023

Cited by 2 | Viewed by 1433

Abstract

Lithium–sulfur (Li-S) batteries are regarded as highly promising energy storage devices due to their high theoretical specific capacity and high energy density. Nevertheless, the commercial application of Li-S batteries is still restricted by poor electrochemical performance. Herein, beaded nanofibers (BNFs) consisting of carbon [...] Read more.

Lithium–sulfur (Li-S) batteries are regarded as highly promising energy storage devices due to their high theoretical specific capacity and high energy density. Nevertheless, the commercial application of Li-S batteries is still restricted by poor electrochemical performance. Herein, beaded nanofibers (BNFs) consisting of carbon and CoSe₂ nanoparticles (CoSe₂/C BNFs) were prepared by electrospinning combined with carbonization and selenization. Benefitting from the synergistic effect of physical adsorption and chemical catalysis, the CoSe₂/C BNFs can effectively inhibit the shuttle effect of lithium polysulfides and improve the rate performance and cycle stability of Li-S batteries. The three-dimensional conductive network provides a fast electron and ion transport pathway as well as sufficient space for alleviating the volume change. CoSe₂ can not only effectively adsorb the lithium polysulfides but also accelerate their conversion reaction. The CoSe₂/C BNFs-S cathode has a high reversible discharge specific capacity of 919.2 mAh g⁻¹ at 0.1 C and presents excellent cycle stability with a low-capacity decay rate of 0.05% per cycle for 600 cycles at 1 C. The combination of the beaded carbon nanofibers and polar metal selenides sheds light on designing high-performance sulfur-based cathodes. Full article

(This article belongs to the Special Issue Nanocomposites for Ion Batteries)

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12 pages, 2501 KiB

Open AccessArticle

Microwave-Assisted Synthesis of Pd Nanoparticles into Wood Block (Pd@wood) as Efficient Catalyst for 4-Nitrophenol and Cr(VI) Reduction

by Zhao Zhang, Arnaud Besserer, Christophe Rose, Nicolas Brosse, Vincent Terrasson and Erwann Guénin

Nanomaterials 2023, 13(17), 2491; https://doi.org/10.3390/nano13172491 - 4 Sep 2023

Viewed by 1148

Abstract

Palladium (Pd) nanoparticle catalysis has attracted increasing attention due to its efficient catalytic activity and its wide application in environmental protection and chemical synthesis. In this work, Pd nanoparticles (about 71 nm) were synthesized in aqueous solution by microwave-assisted thermal synthesis and immobilized [...] Read more.

Palladium (Pd) nanoparticle catalysis has attracted increasing attention due to its efficient catalytic activity and its wide application in environmental protection and chemical synthesis. In this work, Pd nanoparticles (about 71 nm) were synthesized in aqueous solution by microwave-assisted thermal synthesis and immobilized in beech wood blocks as Pd@wood catalysts. The wood blocks were first hydrothermally treated with 10% NaOH solution to improve the internal structure and increase their porosity, thereby providing favorable attachment sites for the formed Pd nanoparticles. The stable deposition of Pd nanoparticle clusters on the internal channels of the wood blocks can be clearly observed. In addition, the catalytic performance of the prepared Pd@wood was investigated through two model reactions: the reduction of 4-nitrophenol and Cr(VI). The Pd@wood catalyst showed 95.4 g⁻¹ s⁻¹ M⁻¹ of normalized rate constant k_norm and 2.03 min⁻¹ of the TOF, respectively. Furthermore, Pd nanoparticles are integrated into the internal structure of wood blocks by microwave-assisted thermal synthesis, which is an effective method for wood functionalization. It benefits metal nanoparticle catalysis in the synthesis of fine chemicals as well as in industrial wastewater treatment. Full article

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19 pages, 12000 KiB

Open AccessReview

Cu-Based Thermocompression Bonding and Cu/Dielectric Hybrid Bonding for Three-Dimensional Integrated Circuits (3D ICs) Application

by Yuan-Chiu Huang, Yu-Xian Lin, Chien-Kang Hsiung, Tzu-Heng Hung and Kuan-Neng Chen

Nanomaterials 2023, 13(17), 2490; https://doi.org/10.3390/nano13172490 - 4 Sep 2023

Cited by 4 | Viewed by 5395

Abstract

Advanced packaging technology has become more and more important in the semiconductor industry because of the benefits of higher I/O density compared to conventional soldering technology. In advanced packaging technology, copper–copper (Cu-Cu) bonding has become the preferred choice due to its excellent electrical [...] Read more.

Advanced packaging technology has become more and more important in the semiconductor industry because of the benefits of higher I/O density compared to conventional soldering technology. In advanced packaging technology, copper–copper (Cu-Cu) bonding has become the preferred choice due to its excellent electrical and thermal properties. However, one of the major challenges of Cu-Cu bonding is the high thermal budget of the bonding process caused by Cu oxidation, which can result in wafer warpage and other back-end-of-line process issues in some cases. Thus, for specific applications, reducing the thermal budget and preventing Cu oxidation are important considerations in low-temperature hybrid bonding processes. This paper first reviews the advancements in low-temperature Cu-based bonding technologies for advanced packaging. Various low-temperature Cu-Cu bonding techniques such as surface pretreatment, surface activation, structure modification, and orientation control have been proposed and investigated. To overcome coplanarity issues of Cu pillars and insufficient gaps for filling, low-temperature Cu-Cu bonding used, but it is still challenging in fine-pitch applications. Therefore, low-temperature Cu/SiO₂, Cu/SiCN, and Cu/polymer hybrid bonding have been developed for advanced packaging applications. Furthermore, we present a novel hybrid bonding scheme for metal/polymer interfaces that achieves good flatness and an excellent bonding interface without the need for the chemical mechanical polishing (CMP) process. Full article

(This article belongs to the Special Issue Innovation in Nanoelectronic Semiconductor Devices and Materials)

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13 pages, 490 KiB

Open AccessArticle

Thermophase Seebeck Coefficient in Hybridized Superconductor-Quantum-Dot-Superconductor Josephson Junction Side-Coupled to Majorana Nanowire

by Yumei Gao, Xiaoyan Zhang, Zichuan Yi, Liming Liu and Feng Chi

Nanomaterials 2023, 13(17), 2489; https://doi.org/10.3390/nano13172489 - 4 Sep 2023

Cited by 3 | Viewed by 1148

Abstract

The dc Josephson current is generated from phase difference between two superconductors separated by a mesoscopic thin film (Josephson junction) without external bias voltage. In the presence of a temperature gradient across the superconductors, a thermal phase is induced under the condition of [...] Read more.

The dc Josephson current is generated from phase difference between two superconductors separated by a mesoscopic thin film (Josephson junction) without external bias voltage. In the presence of a temperature gradient across the superconductors, a thermal phase is induced under the condition of open circuit. This is very similar to the Seebeck effect in the usual thermoelectric effect, and the thermal phase is thus named as thermophase Seebeck coefficient (TPSC). Here we find obvious enhancement and sign change of the TPSC unique to the Josephson junction composing of two superconductors connected to a semiconductor quantum dot (QD), which is additionally side-coupled to a nanowire hosting Majorana bound states (MBSs), the system denoted by S-MQD-S. These result arise from the newly developed states near the Fermi level of the superconductors due to the QD-MBS hybridization when the dot level is within the superconducting gap. The sign change of the TPSC provides a strong evidence of the existence of MBSs, and is absent if the QD is coupled to regular fermion, such as another QD (system denoted by S-DQD-S). We show that the magnitude and sign of the TPSC are sensitive to the physical quantities including interaction strength between the QD and MBSs, direct overlap between the MBSs, system equilibrium temperature, as well as hopping amplitude between the QD and the superconductors. The obtained results are explained with the help of the current-carrying density of the states (CCDOS), and may be useful in interdisciplinary research areas of Josephson and Majorana physics. Full article

(This article belongs to the Special Issue 2D and Carbon Nanomaterials for Energy Conversion and Storage)

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17 pages, 5321 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Adverse Effect of Metallic Gold and Silver Nanoparticles on Xenopus laevis Embryogenesis

by Rosa Carotenuto, Margherita Tussellino, Sabato Fusco, Giovanna Benvenuto, Fabio Formiggini, Bice Avallone, Chiara Maria Motta, Chiara Fogliano and Paolo Antonio Netti

Nanomaterials 2023, 13(17), 2488; https://doi.org/10.3390/nano13172488 - 4 Sep 2023

Viewed by 1393

Abstract

Exposure to metal nanoparticles is potentially harmful, particularly when occurring during embryogenesis. In this study, we tested the effects of commercial AuNPs and AgNPs, widely used in many fields for their features, on the early development of Xenopus laevis, an anuran amphibian [...] Read more.

Exposure to metal nanoparticles is potentially harmful, particularly when occurring during embryogenesis. In this study, we tested the effects of commercial AuNPs and AgNPs, widely used in many fields for their features, on the early development of Xenopus laevis, an anuran amphibian key model species in toxicity testing. Through the Frog Embryo Teratogenesis Assay—Xenopus test (FETAX), we ascertained that both nanoparticles did not influence the survival rate but induced morphological anomalies like modifications of head and branchial arch cartilages, depigmentation of the dorsal area, damage to the intestinal brush border, and heart rate alteration. The expression of genes involved in the early pathways of embryo development was also modified. This study suggests that both types of nanoparticles are toxic though nonlethal, thus indicating that their use requires attention and further study to better clarify their activity in animals and, more importantly, in humans. Full article

(This article belongs to the Special Issue Recent Advances in Metal Nanoparticles and Nanotoxicity)

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11 pages, 6822 KiB

Open AccessArticle

In-Situ Grown NiMn₂O₄/GO Nanocomposite Material on Nickel Foam Surface by Microwave-Assisted Hydrothermal Method and Used as Supercapacitor Electrode

by Shusen Wang, Xiaomei Du, Sen Liu, Yingqing Fu and Naibao Huang

Nanomaterials 2023, 13(17), 2487; https://doi.org/10.3390/nano13172487 - 4 Sep 2023

Cited by 5 | Viewed by 1466

Abstract

The NiMn₂O₄/graphene oxide (GO) nanocomposite material was in situ grown on the surface of a nickel foam 3D skeleton by combining the solvent method with the microwave-assisted hydrothermal method and annealing; then, its performance was investigated as a superior [...] Read more.

The NiMn₂O₄/graphene oxide (GO) nanocomposite material was in situ grown on the surface of a nickel foam 3D skeleton by combining the solvent method with the microwave-assisted hydrothermal method and annealing; then, its performance was investigated as a superior supercapacitor electrode material. When nickel foam was soaked in GO aqueous or treated in nickel ion and manganese ion solution by the microwave-assisted hydrothermal method and annealing, gauze GO film or flower-spherical NiMn₂O₄ was formed on the nickel foam surface. If the two processes were combined in a different order, the final products on the nickel surface had a remarkably different morphology and phase structure. When GO film was first formed, the final products on the nickel surface were the composite of NiO and Mn₃O₄, while NiMn₂O₄/GO nanocomposite material can be obtained if NiMn₂O₄ was first formed (immersed in 2.5 mg/L GO solution). In a 6M KOH solution, the specific capacitance of the latter reached 700 F/g at 1 A/g which was superior to that of the former (only 35 F/g). However, the latter’s specific capacitance was still inferior to that of in-situ grown NiMn₂O₄ on nickel foam (802 F/g). Though the gauze-formed GO film, almost covering the preformed flower-spherical NiMn₂O₄, can also contribute a certain specific capacitance, it also restricted the electrolyte diffusion and contact with NiMn₂O₄, accounting for the performance decrease of the NiMn₂O₄/GO nanocomposite. A convenient method was raised to fabricate the nanocomposite of carbon and double metal oxides. Full article

(This article belongs to the Special Issue From Biomass to Nanomaterials)

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18 pages, 5019 KiB

Open AccessReview

Advances in Nanomaterials Based on Cashew Nut Shell Liquid

by Ermelinda Bloise, Maria Rosaria Lazzoi, Lucia Mergola, Roberta Del Sole and Giuseppe Mele

Nanomaterials 2023, 13(17), 2486; https://doi.org/10.3390/nano13172486 - 4 Sep 2023

Cited by 5 | Viewed by 2609

Abstract

Cashew nut shell liquid (CNSL), obtained as a byproduct of the cashew industry, represents an important natural source of phenolic compounds, with important environmental benefits due to the large availability and low cost of the unique renewable starting material, that can be used [...] Read more.

Cashew nut shell liquid (CNSL), obtained as a byproduct of the cashew industry, represents an important natural source of phenolic compounds, with important environmental benefits due to the large availability and low cost of the unique renewable starting material, that can be used as an alternative to synthetic substances in many industrial applications. The peculiarity of the functional groups of CNSL components, such as phenolic hydroxyl, the aromatic ring, acid functionality, and unsaturation(s) in the C₁₅ alkyl side chain, permitted the design of interesting nanostructures. Cardanol (CA), anacardic acid (AA), and cardol (CD), opportunely isolated from CNSL, served as building blocks for generating an amazing class of nanomaterials with chemical, physical, and morphological properties that can be tuned in view of their applications, particularly focused on their bioactive properties. Full article

(This article belongs to the Special Issue Recent Advances in Green Nanomaterials: Design and Applications)

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16 pages, 2793 KiB

Open AccessArticle

A Cocktail-Based Formula for the Design of Nanosized Cosmeceuticals as Skincare and Anti-Age Products

by Ines Castangia, Federica Fulgheri, Matteo Perra, Gianluigi Bacchetta, Laura Fancello, Francesco Corrias, Iris Usach, Josè Esteban Peris, Maria Letizia Manca and Maria Manconi

Nanomaterials 2023, 13(17), 2485; https://doi.org/10.3390/nano13172485 - 4 Sep 2023

Cited by 1 | Viewed by 1745

Abstract

Nasco and Bovale grape pomace extracts, alone or in association, were loaded in nanoemulsions tailored for cosmetic application, using Kolliphor^®RH40 (kolliphor) as the synthetic surfactant, Olivem^®1000 (olivem) as the natural one, and lecithin as the cosurfactant. Pink transparent or [...] Read more.

Nasco and Bovale grape pomace extracts, alone or in association, were loaded in nanoemulsions tailored for cosmetic application, using Kolliphor^®RH40 (kolliphor) as the synthetic surfactant, Olivem^®1000 (olivem) as the natural one, and lecithin as the cosurfactant. Pink transparent or milky dispersions, as a function of the used extract and surfactant, were obtained to be used as cosmeceutical serum or milk. The sizes of the nanoemulsion droplets were small (≈77 nm with kolliphor and ≈141 nm with olivem), homogenously dispersed (~0.24 with kolliphor and ~0.16 with olivem), highly negatively charged (≈−43 mV irrespective of the used surfactant) and their stability either on storage or under stressing conditions was affected by the used extract and surfactant. Formulations protected the extracts from the degradation caused by UV exposition, were biocompatible against keratinocytes, protected them against oxidative damages induced using hydrogen peroxide and inhibited the release of nitrite induced in macrophages using the lipopolysaccharide inflammatory stimulus. The overall results underlined the key role played by the composition of the formula to achieve a suitable cosmeceutical for skin care but even for the prevention of premature aging and chronic damages caused by the stressing conditions. Full article

(This article belongs to the Special Issue Micro/Nano Emulsions: Fabrication and Applications)

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Graphical abstract

14 pages, 5500 KiB

Open AccessArticle

Low-Vacuum Catalyst-Free Physical Vapor Deposition and Magnetotransport Properties of Ultrathin Bi₂Se₃ Nanoribbons

by Raitis Sondors, Kiryl Niherysh, Jana Andzane, Xavier Palermo, Thilo Bauch, Floriana Lombardi and Donats Erts

Nanomaterials 2023, 13(17), 2484; https://doi.org/10.3390/nano13172484 - 3 Sep 2023

Cited by 1 | Viewed by 1285

Abstract

In this work, a simple catalyst-free physical vapor deposition method is optimized by adjusting source material pressure and evaporation time for the reliable obtaining of freestanding nanoribbons with thicknesses below 15 nm. The optimum synthesis temperature, time and pressure were determined for an [...] Read more.

In this work, a simple catalyst-free physical vapor deposition method is optimized by adjusting source material pressure and evaporation time for the reliable obtaining of freestanding nanoribbons with thicknesses below 15 nm. The optimum synthesis temperature, time and pressure were determined for an increased yield of ultrathin Bi₂Se₃ nanoribbons with thicknesses of 8–15 nm. Physical and electrical characterization of the synthesized Bi₂Se₃ nanoribbons with thicknesses below 15 nm revealed no degradation of properties of the nanoribbons, as well as the absence of the contribution of trivial bulk charge carriers to the total conductance of the nanoribbons. Full article

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15 pages, 13783 KiB

Open AccessArticle

Characterising Hydroxyapatite Deposited from Solution onto Novel Substrates: Growth Mechanism and Physical Properties

by Bríd Murphy, Jhonattan Baez and Mick A. Morris

Nanomaterials 2023, 13(17), 2483; https://doi.org/10.3390/nano13172483 - 3 Sep 2023

Cited by 5 | Viewed by 1303

Abstract

Whilst titanium, stainless steel, and cobalt-chrome alloys are the most common materials for use in orthopaedic implant devices, there are significant advantages in moving to alternative non-metallic substrates. Substrates such as polymers may have advantageous mechanical biological properties whilst other substrates may bring [...] Read more.

Whilst titanium, stainless steel, and cobalt-chrome alloys are the most common materials for use in orthopaedic implant devices, there are significant advantages in moving to alternative non-metallic substrates. Substrates such as polymers may have advantageous mechanical biological properties whilst other substrates may bring unique capability. A key challenge in the use of non-metal products is producing substrates which can be modified to allow the formation of well-adhered hydroxyapatite films which promote osteointegration and have other beneficial properties. In this work, we aim to develop methodology for the growth of hydroxyapatite films on surfaces other than bulk metallic parts using a wet chemical coating process, and we provide a detailed characterisation of the coatings. In this study, hydroxyapatite is grown from saturated solutions onto thin titanium films and silicon substrates and compared to results from titanium alloy substrates. The coating process efficacy is shown to be dependent on substrate roughness, hydrophilicity, and activation. The mechanism of the hydroxyapatite growth is investigated in terms of initial attachment and morphological development using SEM and XPS analysis. XPS analysis reveals the exact chemical state of the hydroxyapatite compositional elements of Ca, P, and O. The characterisation of grown hydroxyapatite layers by XRD reveals that the hydroxyapatite forms from amorphous phases, displaying preferential crystal growth along the [002] direction, with TEM imagery confirming polycrystalline pockets amid an amorphous matrix. SEM-EDX and FTIR confirmed the presence of hydroxyapatite phases through elemental atomic weight percentages and bond assignment. All data are collated and reviewed for the different substrates. The results demonstrate that once hydroxyapatite seeds, it crystallises in the same manner as bulk titanium whether that be on a titanium or silicon substrate. These data suggest that a range of substrates may be coated using this facile hydroxyapatite deposition technique, just broadening the choice of substrate for a particular function. Full article

(This article belongs to the Special Issue Functional Coatings with Nanostructures: Synthesis, Characterizations and Applications)

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14 pages, 12562 KiB

Open AccessArticle

High-Linearity Wireless Passive Temperature Sensor Based on Metamaterial Structure with Rotation-Insensitive Distance-Based Warning Ability

by Chenying Wang, Luntao Chen, Bian Tian and Zhuangde Jiang

Nanomaterials 2023, 13(17), 2482; https://doi.org/10.3390/nano13172482 - 3 Sep 2023

Cited by 2 | Viewed by 1295

Abstract

A wireless passive temperature sensor based on a metamaterial structure is proposed that is capable of measuring the temperature of moving parts. The sensor structure consists of an alumina ceramic substrate with a square metal double split-ring resonator fixed centrally on the ceramic [...] Read more.

A wireless passive temperature sensor based on a metamaterial structure is proposed that is capable of measuring the temperature of moving parts. The sensor structure consists of an alumina ceramic substrate with a square metal double split-ring resonator fixed centrally on the ceramic substrate. Since the dielectric constant of the alumina ceramic substrate is temperature sensitive, the resonant frequency of the sensor is altered due to changes in temperature. A wireless antenna is used to detect the change in the resonant frequency of the sensor using a wireless antenna, thereby realizing temperature sensing operation of the sensor. The temperature sensitivity of the sensor is determined to be 205.22 kHz/°C with a strong linear response when tested over the temperature range of 25–135 °C, which is evident from the R2 being 0.995. Additionally, the frequency variation in this sensor is insensitive to the angle of rotation and can be used for temperature measurement of rotating parts. The sensor also has a distance warning functionality, which offers additional safety for the user by providing early warning signals when the heating equipment overheats after operating for extended durations. Full article

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23 pages, 6435 KiB

Open AccessArticle

Microwave-Assisted Synthesis of Pt/SnO₂ for the Catalytic Reduction of 4-Nitrophenol to 4-Aminophenol

by Izabela Đurasović, Goran Štefanić, Goran Dražić, Robert Peter, Zoltán Klencsár, Marijan Marciuš, Tanja Jurkin, Mile Ivanda, Sándor Stichleutner and Marijan Gotić

Nanomaterials 2023, 13(17), 2481; https://doi.org/10.3390/nano13172481 - 2 Sep 2023

Cited by 3 | Viewed by 1780

Abstract

In this study, we present a new approach for the synthesis of Pt/SnO₂ catalysts using microwave radiation. Pt(IV) and Sn(IV) inorganic precursors (H₂PtCl₆ and SnCl₄) and ammonia were used, which allowed the controlled formation of platinum particles [...] Read more.

In this study, we present a new approach for the synthesis of Pt/SnO₂ catalysts using microwave radiation. Pt(IV) and Sn(IV) inorganic precursors (H₂PtCl₆ and SnCl₄) and ammonia were used, which allowed the controlled formation of platinum particles on the anisotropic SnO₂ support. The synthesized Pt/SnO₂ samples are mesoporous and exhibit a reversible physisorption isotherm of type IV. The XRD patterns confirmed the presence of platinum maxima in all Pt/SnO₂ samples. The Williamson-Hall diagram showed SnO₂ anisotropy with crystallite sizes of ~10 nm along the c-axis (< 00l >) and ~5 nm along the a-axis (< h00 >). SEM analysis revealed anisotropic, urchin-like SnO₂ particles. XPS results indicated relatively low average oxidation states of platinum, close to Pt metal. ¹¹⁹Sn Mössbauer spectroscopy indicated electronic interactions between Pt and SnO₂ particles. The synthesized samples were used for the catalytic reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the presence of excess NaBH₄. The catalytic activity of the Pt/SnO₂ samples for the reduction of 4-NP to 4-AP was optimized by varying the synthesis parameters and Pt loading. The optimal platinum loading for the reduction of 4-NP to 4-AP on the anisotropic SnO₂ support is 5 mol% with an apparent rate constant k = 0.59 × 10^–2 s^–1. The Pt/SnO₂ sample showed exceptional reusability and retained an efficiency of 81.4% after ten cycles. Full article

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11 pages, 2346 KiB

Open AccessArticle

Study of the Scattering Effect by SiO₂ Nanoparticles, in a Luminescent Solar Concentrator Sensitized with Carbon Dots

by Mackenson Polché, Blancas Flores José Miguel, Carlos Alberto Guzmán González, Gabriel González Contreras and Victor Hugo Romero Arellano

Nanomaterials 2023, 13(17), 2480; https://doi.org/10.3390/nano13172480 - 2 Sep 2023

Cited by 3 | Viewed by 1624

Abstract

Luminescent solar concentrators (LSCs) have become an attractive way to produce green energy via their integration into buildings as photovoltaic windows. Recently, carbon quantum dots (C-QDs) have become the most studied luminescent material for the manufacture of luminescent solar concentrators due to their [...] Read more.

Luminescent solar concentrators (LSCs) have become an attractive way to produce green energy via their integration into buildings as photovoltaic windows. Recently, carbon quantum dots (C-QDs) have become the most studied luminescent material for the manufacture of luminescent solar concentrators due to their advantages, such as low toxicity, sustainability, and low cost. Despite the advantages of carbon quantum dots, they remain a low-efficiency material, and it is difficult to fabricate LSCs with a good performance. To address this problem, some of the research has used SiO₂ nanoparticles (Nps) to produce a light-scattering effect that helps to improve the system performance. However, these studies are limited and have not been discussed in detail. In this regard, this research work was designed to evaluate the contribution of the scattering effect in different systems of carbon quantum dots used in a possible luminescent solar concentrator. To carry out this study, C-QDs and SiO₂ Nps were synthesized by hydrothermal methods and the Stober method, respectively. We used different concentrations of both materials to fabricate film LSCs (10 × 10 cm²). The results show that the light scattered by the SiO₂ Nps has a double contribution, in terms of light redirected towards the edges of the window and as a secondary source of excitation for the C-QDs; thus, an improvement in the performance of the LSC is achieved. The best improvement in photoluminescence is achieved when the films are composed of 20% wt carbon quantum dots and 10% wt SiO₂ Nps, reaching a gain of 16% of the intensity of the light incident on the edges of the window with respect to the LSCs where only C-QDs were used. Full article

(This article belongs to the Special Issue Applications of Luminescent Nanoparticles)

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14 pages, 5790 KiB

Open AccessArticle

Human Dental Pulp Mesenchymal Stem Cell-Derived Soluble Factors Combined with a Nanostructured Scaffold Support the Generation of a Vascular Network In Vivo

by Ludovica Barone, Matteo Gallazzi, Federica Rossi, Roberto Papait, Mario Raspanti, Piero Antonio Zecca, Luca Buonarrivo, Barbara Bassani, Giovanni Bernardini, Antonino Bruno and Rosalba Gornati

Nanomaterials 2023, 13(17), 2479; https://doi.org/10.3390/nano13172479 - 2 Sep 2023

Cited by 2 | Viewed by 1739

Abstract

Among all strategies directed at developing new tools to support re-vascularization of damaged tissues, the use of pro-angiogenic soluble factors, derived from mesenchymal stem cells (MSCs), appears a promising approach for regenerative medicine. Here, we compared the feasibility of two devices, generated by [...] Read more.

Among all strategies directed at developing new tools to support re-vascularization of damaged tissues, the use of pro-angiogenic soluble factors, derived from mesenchymal stem cells (MSCs), appears a promising approach for regenerative medicine. Here, we compared the feasibility of two devices, generated by coupling soluble factors of human dental pulp mesenchymal stem cells (DPSCs), with a nanostructured scaffold, to support angiogenesis once transplanted in mice. DPSCs were obtained from impacted wisdom tooth removal, usually considered surgical waste material. After 28 days, we verified the presence of active blood vessels inside the scaffold through optical and scansion electron microscopy. The mRNA expression of surface antigens related to macrophage polarization (CD68, CD80, CD86, CD163, CD206), as well as pro-angiogenic markers (CD31, CD34, CD105, Angpt1, Angpt2, CDH5) was evaluated by real-time PCR. Our results demonstrate the capability of DPSC–scaffold and DPSC soluble factors–scaffold to support angiogenesis, similarly to adipose stem cells, whereas the absence of blood vessels was found in the scaffold grafted alone. Our results provide evidence that DPSC-conditioned medium can be proposed as a cell-free preparation able to support angiogenesis, thus, providing a relevant tool to overcome the issues and restrictions associated with the use of cells. Full article

(This article belongs to the Topic Advanced Functional Materials for Regenerative Medicine)

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15 pages, 2703 KiB

Open AccessArticle

Synthesis of Cu Nanoparticles Incorporated Mesoporous C/SiO₂ for Efficient Tetracycline Degradation

by Ning Wang, Yuanyuan Zhao, Xuelian Wu, Dapeng Li, Ruguang Ma, Zhigang Chen and Zhengying Wu

Nanomaterials 2023, 13(17), 2478; https://doi.org/10.3390/nano13172478 - 2 Sep 2023

Cited by 1 | Viewed by 1333

Abstract

In this study, a Cu NPs-incorporated carbon-containing mesoporous SiO₂ (Cu/C-SiO₂) was successfully synthesized through a grinding-assisted self-infiltration method followed by an in situ reduction process. The obtained Cu/C-SiO₂ was then employed as a Fenton-like catalyst to remove tetracycline (TC) [...] Read more.

In this study, a Cu NPs-incorporated carbon-containing mesoporous SiO₂ (Cu/C-SiO₂) was successfully synthesized through a grinding-assisted self-infiltration method followed by an in situ reduction process. The obtained Cu/C-SiO₂ was then employed as a Fenton-like catalyst to remove tetracycline (TC) from aqueous solutions. TEM, EDS, XRD, N₂ adsorption–desorption, FTIR, and XPS methods were used to characterize the crystal structure, morphology, porosity, chemical composition, and surface chemical properties of the catalyst. The effects of initial TC concentration, catalyst dosage, H₂O₂ dosage, solution pH, HA addition, and water media on the TC degradation over Cu/C-SiO₂ were investigated. Scavenging and electrochemical experiments were then carried out to analyze the TC degradation mechanism. The results show that the Cu/C-SiO₂ can remove 99.9% of the concentrated TC solution (C₀ = 500 mg·L⁻¹), and it can be used in a wide pH range (R.E. = 94–99%, pH = 3.0–11.0). Moreover, hydroxyl radicals (•OH) were detected to be the dominant reactive species in this catalytic system. This study provides a simple and promising method for the synthesis of heteroatom-containing mesoporous catalysts for the decomposition of antibiotics in wastewater. Full article

(This article belongs to the Special Issue Carbon Nanomaterials for Green Energy Storage and Catalysis Applications)

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13 pages, 2947 KiB

Open AccessArticle

Artificial Synapse Emulated by Indium Tin Oxide/SiN/TaN Resistive Switching Device for Neuromorphic System

by Dongyeol Ju, Sunghun Kim and Sungjun Kim

Nanomaterials 2023, 13(17), 2477; https://doi.org/10.3390/nano13172477 - 1 Sep 2023

Cited by 10 | Viewed by 1412

Abstract

In this paper, we fabricate an ITO/SiN/TaN memristor device and analyze its electrical characteristics for a neuromorphic system. The device structure and chemical properties are investigated using transmission electron microscopy and X-ray photoelectron spectroscopy. Uniform bipolar switching is achieved through DC sweep under [...] Read more.

In this paper, we fabricate an ITO/SiN/TaN memristor device and analyze its electrical characteristics for a neuromorphic system. The device structure and chemical properties are investigated using transmission electron microscopy and X-ray photoelectron spectroscopy. Uniform bipolar switching is achieved through DC sweep under a compliance current of 5 mA. Also, the analog reset phenomenon is observed by modulating the reset voltage for long-term memory. Additionally, short-term memory characteristics are obtained by controlling the strength of the pulse response. Finally, bio-inspired synaptic characteristics are emulated using Hebbian learning rules such as spike-rate-dependent plasticity (SRDP) and spike-timing-dependent plasticity (STDP). As a result, we believe that the coexistence of short-term and long-term memories in the ITO/SiN/TaN device can provide flexibility in device design in future neuromorphic applications. Full article

(This article belongs to the Collection Nanoarchitectonics of the Fourth Fundamental Electronic Component: Memristor, Meminductor and Memcapacitor)

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34 pages, 2806 KiB

Open AccessReview

Peptides Targeting HER2-Positive Breast Cancer Cells and Applications in Tumor Imaging and Delivery of Chemotherapeutics

by Palmira Alessia Cavallaro, Marzia De Santo, Emilia Lucia Belsito, Camilla Longobucco, Manuela Curcio, Catia Morelli, Luigi Pasqua and Antonella Leggio

Nanomaterials 2023, 13(17), 2476; https://doi.org/10.3390/nano13172476 - 1 Sep 2023

Cited by 13 | Viewed by 5235

Abstract

Breast cancer represents the most common cancer type and one of the major leading causes of death in the female worldwide population. Overexpression of HER2, a transmembrane glycoprotein related to the epidermal growth factor receptor, results in a biologically and clinically aggressive breast [...] Read more.

Breast cancer represents the most common cancer type and one of the major leading causes of death in the female worldwide population. Overexpression of HER2, a transmembrane glycoprotein related to the epidermal growth factor receptor, results in a biologically and clinically aggressive breast cancer subtype. It is also the primary driver for tumor detection and progression and, in addition to being an important prognostic factor in women diagnosed with breast cancer, HER2 is a widely known therapeutic target for drug development. The aim of this review is to provide an updated overview of the main approaches for the diagnosis and treatment of HER2-positive breast cancer proposed in the literature over the past decade. We focused on the different targeting strategies involving antibodies and peptides that have been explored with their relative outcomes and current limitations that need to be improved. The review also encompasses a discussion on targeted peptides acting as probes for molecular imaging. By using different types of HER2-targeting strategies, nanotechnology promises to overcome some of the current clinical challenges by developing novel HER2-guided nanosystems suitable as powerful tools in breast cancer imaging, targeting, and therapy. Full article

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25 pages, 2289 KiB

Open AccessReview

The Potential of Trichoderma-Mediated Nanotechnology Application in Sustainable Development Scopes

by Ali Athafah Tomah, Zhen Zhang, Iman Sabah Abd Alamer, Arif Ali Khattak, Temoor Ahmed, Minjun Hu, Daoze Wang, Lihui Xu, Bin Li and Yanli Wang

Nanomaterials 2023, 13(17), 2475; https://doi.org/10.3390/nano13172475 - 1 Sep 2023

Cited by 8 | Viewed by 2381

Abstract

The environmental impact of industrial development has been well-documented. The use of physical and chemical methods in industrial development has negative consequences for the environment, raising concerns about the sustainability of this approach. There is a growing need for advanced technologies that are [...] Read more.

The environmental impact of industrial development has been well-documented. The use of physical and chemical methods in industrial development has negative consequences for the environment, raising concerns about the sustainability of this approach. There is a growing need for advanced technologies that are compatible with preserving the environment. The use of fungi products for nanoparticle (NP) synthesis is a promising approach that has the potential to meet this need. The genus Trichoderma is a non-pathogenic filamentous fungus with a high degree of genetic diversity. Different strains of this genus have a variety of important environmental, agricultural, and industrial applications. Species of Trichoderma can be used to synthesize metallic NPs using a biological method that is environmentally friendly, low cost, energy saving, and non-toxic. In this review, we provide an overview of the role of Trichoderma metabolism in the synthesis of metallic NPs. We discuss the different metabolic pathways involved in NP synthesis, as well as the role of metabolic metabolites in stabilizing NPs and promoting their synergistic effects. In addition, the future perspective of NPs synthesized by extracts of Trichoderma is discussed, as well as their potential applications in biomedicine, agriculture, and environmental health. Full article

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16 pages, 13674 KiB

Open AccessArticle

Quadruple Plasmon-Induced Transparency and Dynamic Tuning Based on Bilayer Graphene Terahertz Metamaterial

by Jiayu Zhang, Junyi Li, Shuxian Chen, Kunhua Wen and Wenjie Liu

Nanomaterials 2023, 13(17), 2474; https://doi.org/10.3390/nano13172474 - 1 Sep 2023

Cited by 1 | Viewed by 1243

Abstract

This study proposes a terahertz metamaterial structure composed of a silicon–graphene–silicon sandwich, aiming to achieve quadruple plasmon-induced transparency (PIT). This phenomenon arises from the interaction coupling of bright–dark modes within the structure. The results obtained from the coupled mode theory (CMT) calculations align [...] Read more.

This study proposes a terahertz metamaterial structure composed of a silicon–graphene–silicon sandwich, aiming to achieve quadruple plasmon-induced transparency (PIT). This phenomenon arises from the interaction coupling of bright–dark modes within the structure. The results obtained from the coupled mode theory (CMT) calculations align with the simulations ones using the finite difference time domain (FDTD) method. Based on the electric field distributions at the resonant frequencies of the five bright modes, it is found that the energy localizations of the original five bright modes undergo diffusion and transfer under the influence of the dark mode. Additionally, the impact of the Fermi level of graphene on the transmission spectrum is discussed. The results reveal that the modulation depths (MDs) of 94.0%, 92.48%, 93.54%, 96.54%, 97.51%, 92.86%, 94.82%, and 88.20%, with corresponding insertion losses (ILs) of 0.52 dB, 0.98 dB, 1.37 dB, 0.70 dB, 0.43 dB, 0.63 dB, 0.16 dB, and 0.17 dB at the specific frequencies, are obtained, achieving multiple switching effects. This model holds significant potential for applications in versatile modulators and optical switches in the terahertz range. Full article

(This article belongs to the Special Issue Advanced Nanostructure in Terahertz Technology and Applications)

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5 pages, 200 KiB

Open AccessEditorial

Special Issue “Theoretical Calculation and Molecular Modeling of Nanomaterials”

by Frederik Tielens

Nanomaterials 2023, 13(17), 2473; https://doi.org/10.3390/nano13172473 - 1 Sep 2023

Viewed by 974

Abstract

The continuous advancement of computational chemistry and the chemical modeling of materials is closely aligned with the ever-evolving computational power and related techniques [...] Full article

(This article belongs to the Special Issue Theoretical Calculation and Molecular Modeling of Nanomaterials)

4 pages, 1076 KiB

Open AccessEditorial

Filled Carbon Nanotubes: Promising Material for Applications

by Marianna V. Kharlamova

Nanomaterials 2023, 13(17), 2472; https://doi.org/10.3390/nano13172472 - 1 Sep 2023

Cited by 2 | Viewed by 1346

Abstract

Carbon nanotubes (CNTs) were first filled with a number of metals starting in 1993 [...] Full article

(This article belongs to the Special Issue Applications of Functionalized Carbon Nanomaterials: Advances and Perspectives)

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17 pages, 3507 KiB

Open AccessArticle

Silver–Gold Alloy Nanoparticles (AgAu NPs): Photochemical Synthesis of Novel Biocompatible, Bimetallic Alloy Nanoparticles and Study of Their In Vitro Peroxidase Nanozyme Activity

by Prakash G. Kshirsagar, Valeria De Matteis, Sudipto Pal and Shiv Shankar Sangaru

Nanomaterials 2023, 13(17), 2471; https://doi.org/10.3390/nano13172471 - 1 Sep 2023

Cited by 3 | Viewed by 1761

Abstract

Facile synthesis of metal nanoparticles with controlled physicochemical properties using environment-friendly reagents can open new avenues in biomedical applications. Nanomaterials with controlled physicochemical properties have opened new prospects for a variety of applications. In the present study, we report a single-step photochemical synthesis [...] Read more.

Facile synthesis of metal nanoparticles with controlled physicochemical properties using environment-friendly reagents can open new avenues in biomedical applications. Nanomaterials with controlled physicochemical properties have opened new prospects for a variety of applications. In the present study, we report a single-step photochemical synthesis of ~5 nm-sized silver (Ag) and gold (Au) nanoparticles (NPs), and Ag–Au alloy nanoparticles using L-tyrosine. The physicochemical and surface properties of both monometallic and bimetallic NPs were investigated by analytical, spectroscopic, and microscopic techniques. Our results also displayed an interaction between L-tyrosine and surface atoms that leads to the formation of AgAu NPs by preventing the growth and aggregation of the NPs. This method efficiently produced monodispersed NPs, with a narrow-sized distribution and good stability in an aqueous solution. The cytotoxicity assessment performed on breast cancer cell lines (MCF-7) revealed that the biofriendly L-tyrosine-capped AgNPs, AuNPs, and bimetallic AgAu NPs were biocompatible. Interestingly, AgAu NPs have also unveiled controlled cytotoxicity, cell viability, and in vitro peroxidase nanozyme activity reliant on metal composition and surface coating. Full article

(This article belongs to the Special Issue Recent Advances in the Construction and Applications of Nanozymes)

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17 pages, 5073 KiB

Open AccessArticle

Chitin Nanofibrils Enabled Core–Shell Microcapsules of Alginate Hydrogel

by Thakur Sapkota, Bishnu Kumar Shrestha, Sita Shrestha and Narayan Bhattarai

Nanomaterials 2023, 13(17), 2470; https://doi.org/10.3390/nano13172470 - 1 Sep 2023

Viewed by 1578

Abstract

An engineered 3D architectural network of the biopolymeric hydrogel can mimic the native cell environment that promotes cell infiltration and growth. Among several bio-fabricated hydrogel structures, core–shell microcapsules inherit the potential of cell encapsulation to ensure the growth and transport of cells and [...] Read more.

An engineered 3D architectural network of the biopolymeric hydrogel can mimic the native cell environment that promotes cell infiltration and growth. Among several bio-fabricated hydrogel structures, core–shell microcapsules inherit the potential of cell encapsulation to ensure the growth and transport of cells and cell metabolites. Herein, a co-axial electrostatic encapsulation strategy is used to create and encapsulate the cells into chitin nanofibrils integrated alginate hydrogel microcapsules. Three parameters that are critical in the electrostatic encapsulation process, hydrogel composition, flow rate, and voltage were optimized. The physicochemical characterization including structure, size, and stability of the core–shell microcapsules was analyzed by scanning electron microscope (SEM), FTIR, and mechanical tests. The cellular responses of the core–shell microcapsules were evaluated through in vitro cell studies by encapsulating NIH/3T3 fibroblast cells. Notably, the bioactive microcapsule showed that the cell viability was found excellent for more than 2 weeks. Thus, the results of this core–shell microcapsule showed a promising approach to creating 3D hydrogel networks suitable for different biomedical applications such as in vitro tissue models for toxicity studies, wound healing, and tissue repair. Full article

(This article belongs to the Section Nanocomposite Materials)

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11 pages, 1430 KiB

Open AccessArticle

Ambipolar to Unipolar Conversion in C₇₀/Ferrocene Nanosheet Field-Effect Transistors

by Dorra Mahdaoui, Chika Hirata, Kahori Nagaoka, Kun’ichi Miyazawa, Kazuko Fujii, Toshihiro Ando, Manef Abderrabba, Osamu Ito, Shinjiro Yagyu, Yubin Liu, Yoshiyuki Nakajima, Kazuhito Tsukagoshi and Takatsugu Wakahara

Nanomaterials 2023, 13(17), 2469; https://doi.org/10.3390/nano13172469 - 1 Sep 2023

Viewed by 1328

Abstract

Organic cocrystals, which are assembled by noncovalent intermolecular interactions, have garnered intense interest due to their remarkable chemicophysical properties and practical applications. One notable feature, namely, the charge transfer (CT) interactions within the cocrystals, not only facilitates the formation of an ordered supramolecular [...] Read more.

Organic cocrystals, which are assembled by noncovalent intermolecular interactions, have garnered intense interest due to their remarkable chemicophysical properties and practical applications. One notable feature, namely, the charge transfer (CT) interactions within the cocrystals, not only facilitates the formation of an ordered supramolecular network but also endows them with desirable semiconductor characteristics. Here, we present the intriguing ambipolar CT properties exhibited by nanosheets composed of single cocrystals of C₇₀/ferrocene (C₇₀/Fc). When heated to 150 °C, the initially ambipolar monoclinic C₇₀/Fc nanosheet-based field-effect transistors (FETs) were transformed into n-type face-centered cubic (fcc) C₇₀ nanosheet-based FETs owing to the elimination of Fc. This thermally induced alteration in the crystal structure was accompanied by an irreversible switching of the semiconducting behavior of the device; thus, the device transitions from ambipolar to unipolar. Importantly, the C₇₀/Fc nanosheet-based FETs were also found to be much more thermally stable than the previously reported C₆₀/Fc nanosheet-based FETs. Furthermore, we conducted visible/near-infrared diffuse reflectance and photoemission yield spectroscopies to investigate the crucial role played by Fc in modulating the CT characteristics. This study provides valuable insights into the overall functionality of these nanosheet structures. Full article

(This article belongs to the Special Issue Semiconductor Nanomaterials: Growth, Characterization and Optoelectronic Application)

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11 pages, 1055 KiB

Open AccessArticle

Effect of Exposure Concentration and Growth Conditions on the Association of Cerium Oxide Nanoparticles with Green Algae

by Aiga Mackevica, Lyndsey Hendriks, Olga Meili-Borovinskaya, Anders Baun and Lars Michael Skjolding

Nanomaterials 2023, 13(17), 2468; https://doi.org/10.3390/nano13172468 - 1 Sep 2023

Cited by 2 | Viewed by 1557

Abstract

The increasing release of engineered nanoparticles (NPs) into aquatic ecosystems makes it crucial to understand the interactions of NPs with aquatic organisms, such as algae. In this study, the association of CeO₂ NPs with unicellular algae (Raphidocelis subcapitata) and changes [...] Read more.

The increasing release of engineered nanoparticles (NPs) into aquatic ecosystems makes it crucial to understand the interactions of NPs with aquatic organisms, such as algae. In this study, the association of CeO₂ NPs with unicellular algae (Raphidocelis subcapitata) and changes to the cellular elemental profile were investigated using three exposure concentrations (1, 50, and 1000 µg CeO₂/L) at two different algal growth conditions—exponential and inhibited growth (1% glutaraldehyde). After a 24 h-exposure, algal suspensions were settled by gravity and CeO₂-NP/algae association was analyzed by single-cell inductively coupled plasma quadrupole mass spectrometry (sc-ICP-QMS) and ICP time-of-flight MS (sc-ICP-TOFMS). Concurrent detection of the cellular fingerprint with cerium indicated NP association with algae (adsorption/uptake) and changes in the cellular elemental profiles. Less than 5% of cells were associated with NPs when exposed to 1 µg/L. For 50 µg/L exposures in growing and inhibited cell treatments, 4% and 16% of cells were associated with CeO₂ NPs, respectively. ICP-TOFMS analysis made it possible to exclude cellular exudates associated with CeO₂ NPs due to the cellular fingerprint. Growing and inhibited cells had different elemental profile changes following exposure to CeO₂ NPs—e.g., growing cells had higher Mg and lower P contents independent of CeO₂ concentration compared to inhibited cells. Full article

(This article belongs to the Special Issue Ecotoxicity Assessment of Nanomaterials: Latest Advances and Prospects)

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10 pages, 2255 KiB

Open AccessArticle

Facile Transfer of Spray-Coated Ultrathin AgNWs Composite onto the Skin for Electrophysiological Sensors

by Minwoo Lee, Jaeseong Kim, Myat Thet Khine, Sunkook Kim and Srinivas Gandla

Nanomaterials 2023, 13(17), 2467; https://doi.org/10.3390/nano13172467 - 31 Aug 2023

Cited by 6 | Viewed by 1457

Abstract

Disposable wearable sensors that ultrathin and conformable to the skin are of significant interest as affordable and easy-to-use devices for short-term recording. This study presents a facile and low-cost method for transferring spray-coated silver nanowire (AgNW) composite films onto human skin using glossy [...] Read more.

Disposable wearable sensors that ultrathin and conformable to the skin are of significant interest as affordable and easy-to-use devices for short-term recording. This study presents a facile and low-cost method for transferring spray-coated silver nanowire (AgNW) composite films onto human skin using glossy paper (GP) and liquid bandages (LB). Due to the moderately hydrophobic and rough surface of the GP, the ultrathin AgNWs composite film (~200 nm) was easily transferred onto human skin. The AgNW composite films conformally attached to the skin when applied with a LB, resulting in the stable and continuous recording of wearable electrophysiological signals, including electromyogram (EMG), electrocardiogram (ECG), and electrooculogram (EOG). The volatile LB, deposited on the skin via spray coating, promoted rapid adhesion of the transferred AgNW composite films, ensuring stability to the AgNWs in external environments. The AgNWs composite supported with the LB film exhibited high water vapor breathability (~28 gm⁻²h⁻¹), which can avoid the accumulation of sweat at the skin–sensor interface. This approach facilitates the creation of rapid, low-cost, and disposable tattoo-like sensors that are practical for extended use. Full article

(This article belongs to the Special Issue Advanced Nanomaterials for Soft and Wearable Electronics)

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23 pages, 5730 KiB

Open AccessReview

Lasing from Micro- and Nano-Scale Photonic Disordered Structures for Biomedical Applications

by R. Gayathri, C. S. Suchand Sandeep, C. Vijayan and V. M. Murukeshan

Nanomaterials 2023, 13(17), 2466; https://doi.org/10.3390/nano13172466 - 31 Aug 2023

Cited by 7 | Viewed by 2078

Abstract

A disordered photonic medium is one in which scatterers are distributed randomly. Light entering such media experiences multiple scattering events, resulting in a “random walk”-like propagation. Micro- and nano-scale structured disordered photonic media offer platforms for enhanced light–matter interaction, and in the presence [...] Read more.

A disordered photonic medium is one in which scatterers are distributed randomly. Light entering such media experiences multiple scattering events, resulting in a “random walk”-like propagation. Micro- and nano-scale structured disordered photonic media offer platforms for enhanced light–matter interaction, and in the presence of an appropriate gain medium, coherence-tunable, quasi-monochromatic lasing emission known as random lasing can be obtained. This paper discusses the fundamental physics of light propagation in micro- and nano-scale disordered structures leading to the random lasing phenomenon and related aspects. It then provides a state-of-the-art review of this topic, with special attention to recent advancements of such random lasers and their potential biomedical imaging and biosensing applications. Full article

(This article belongs to the Special Issue Nano-Photonics and Meta-Nanomaterials)

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