First-Principles Investigation of Size Effects on Cohesive Energies of Transition-Metal Nanoclusters
Enhanced Thermal Conductivity and Dielectric Properties of Epoxy Composites with Fluorinated Graphene Nanofillers
A Breakthrough in Photocatalytic Wastewater Treatment: The Incredible Potential of g-C₃N₄/Titanate Perovskite-Based Nanocomposites
The Influences of Pore Blockage by Natural Organic Matter and Pore Dimension Tuning on Pharmaceutical Adsorption onto GO-Fe₃O₄
Magnetic Analysis of MgFe Hydrotalcites as Powder and Dispersed in Thin Films within a Keratin Matrix

Journal Description

Nanomaterials

Nanomaterials is an international, peer-reviewed, open access journal published semimonthly online by MDPI.

Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
High Visibility: indexed within Scopus, SCIE (Web of Science), PubMed, PMC, CAPlus / SciFinder, Inspec, and other databases.
Journal Rank: JCR - Q1 (Physics, Applied) / CiteScore - Q1 (General Chemical Engineering)
Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 11.7 days after submission; acceptance to publication is undertaken in 2.6 days (median values for papers published in this journal in the first half of 2023).
Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
Companion journals for Nanomaterials include: Nanomanufacturing and Applied Nano.

Impact Factor: 5.3 (2022); 5-Year Impact Factor: 5.4 (2022)

Imprint Information Journal Flyer Open Access ISSN: 2079-4991

Latest Articles

Open AccessArticle

Synergistic Enhancement of Near-Infrared Emission in CsPbCl₃ Host via Co-Doping with Yb³⁺ and Nd³⁺ for Perovskite Light Emitting Diodes

Muhammad Amin Padhiar

and

Nanomaterials 2023, 13(19), 2703; https://doi.org/10.3390/nano13192703 - 04 Oct 2023

Abstract

Perovskite nanocrystals (PeNCs) have emerged as a promising class of luminescent materials offering size and composition-tunable luminescence with high efficiency and color purity in the visible range. PeNCs doped with Yb³⁺ ions, known for their near-infrared (NIR) emission properties, have gained significant attention due to their potential applications. However, these materials still face challenges with weak NIR electroluminescence (EL) emission and low external quantum efficiency (EQE), primarily due to undesired resonance energy transfer (RET) occurring between the host and Yb³⁺ ions, which adversely affects their emission efficiency and device performance. Herein, we report the synergistic enhancement of NIR emission in a CsPbCl₃ host through co-doping with Yb³⁺/Nd³⁺ ions for perovskite LEDs (PeLEDs). The co-doping of Yb³⁺/Nd³⁺ ions in a CsPbCl₃ host resulted in enhanced NIR emission above 1000 nm, which is highly desirable for NIR optoelectronic applications. This cooperative energy transfer between Yb³⁺ and Nd³⁺ can enhance the overall efficiency of energy conversion. Furthermore, the PeLEDs incorporating the co-doped CsPbCl₃/Yb³⁺/Nd³⁺ PeNCs as an emitting layer exhibited significantly enhanced NIR EL compared to the single doped PeLEDs. The optimized co-doped PeLEDs showed improved device performance, including increased EQE of 6.2% at 1035 nm wavelength and low turn-on voltage. Our findings highlight the potential of co-doping with Yb³⁺ and Nd³⁺ ions as a strategy for achieving synergistic enhancement of NIR emission in CsPbCl₃ perovskite materials, which could pave the way for the development of highly efficient perovskite LEDs for NIR optoelectronic applications. Full article

(This article belongs to the Special Issue Synthesis, Characterization, and Application of Luminescent Nanomaterials)

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Open AccessArticle

Mechanical and Optical Properties of Cr₂O₃ Thin Films Grown by Atomic Layer Deposition Method Using Cr(thd)₃ and Ozone

and

Nanomaterials 2023, 13(19), 2702; https://doi.org/10.3390/nano13192702 - 04 Oct 2023

Abstract

Cr₂O₃ thin films were grown on a Si (1 0 0) substrate using Cr(thd)₃ and O₃ by atomic layer deposition (ALD) at substrate temperatures (T_G) from 200 to 300 °C. X-ray amorphous films were deposited at a T_G ≤ 225 °C, whereas at higher temperatures (T_G ≥ 250 °C), the eskolaite phase was observed in the films. The growth rate of the films increased from 0.003 to 0.01 nm/cycle by increasing T_G from 200 to 275 °C. The relatively low growth rate of Cr(thd)₃—O₃ makes it appropriate for the ALD of precisely controllable solid solution-type ternary-component thin films. The Ti-doped Cr₂O₃ film showed higher hardness (16.7 GPa) compared with that of the undoped film (12.8 GPa) with similar thickness. The band gap values of the pure Cr₂O₃ corresponding to the indirect transition model showed no dependence on T_G; however, doping the Cr₂O₃ with Ti decreased its band gap energy value from 3.1 to 2.2 eV. Full article

(This article belongs to the Section Nanocomposite Materials)

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Open AccessArticle

Visualization of Hot Carrier Dynamics in a Single CsPbBr₃ Perovskite Microplate Using Femtosecond Kerr-Gated Wide-Field Fluorescence Spectroscopy

and

Nanomaterials 2023, 13(19), 2701; https://doi.org/10.3390/nano13192701 - 04 Oct 2023

Abstract

Lead halide perovskites (LHPs) have excellent semiconductor properties. They have been used in many applications such as solar cells. Recently, the hot carrier dynamics in this type of material have received much attention as they are useful for enhancing the performance of optoelectrical devices fabricated from it. Here, we study the ultrafast hot carrier dynamics of a single CsPbBr₃ microplate using femtosecond Kerr-gated wide-field fluorescence spectroscopy. The transient photoluminescence spectra have been measured under a variety of excitation fluences. The temporal evolution of bandgap renormalization and the competition between hot carrier cooling and the recovery of the renormalized bandgap are clearly revealed. Full article

(This article belongs to the Special Issue State-of-the-Art Nanomaterials for Energy Storage/Conversion and Electrocatalysis in Asia)

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Open AccessArticle

High-Performance Infrared Detectors Based on Black Phosphorus/Carbon Nanotube Heterojunctions

and

Nanomaterials 2023, 13(19), 2700; https://doi.org/10.3390/nano13192700 - 04 Oct 2023

Abstract

Infrared detectors have broad application prospects in the fields of detection and communication. Using ideal materials and good device structure is crucial for achieving high-performance infrared detectors. Here, we utilized black phosphorus (BP) and single-walled carbon nanotube (SWCNT) films to construct a vertical van der Waals heterostructure, resulting in high-performance photovoltaic infrared detectors. In the device, a strong built-in electric field was formed in the heterojunction with a favored energy-band matching between the BP and the SWCNT, which caused a good photovoltaic effect. The fabricated devices exhibited a diode-like rectification behavior in the dark, which had a high rectification ratio up to a magnitude of 10⁴ and a low ideal factor of 1.4. Under 1550 nm wavelength illumination, the 2D BP/SWCNT film photodetector demonstrated an open-circuit voltage of 0.34 V, a large external power conversion efficiency (η) of 7.5% and a high specific detectivity (D*) of 3.1 × 10⁹ Jones. This external η was the highest among those for the photovoltaic devices fabricated with the SWCNTs or the heterostructures based on 2D materials and the obtained D* was also higher than those for most of the infrared detectors based on 2D materials or carbon materials. This work showcases the application potential of BP and SWCNTs in the detection field. Full article

(This article belongs to the Section Nanoelectronics, Nanosensors and Devices)

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Open AccessArticle

DFT Study of WS₂-Based Nanotubes Electronic Properties under Torsion Deformations

Anton V. Domnin

Ilia E. Mikhailov

and

Robert A. Evarestov

Nanomaterials 2023, 13(19), 2699; https://doi.org/10.3390/nano13192699 - 04 Oct 2023

Abstract

In this study, the influence of torsional deformations on the properties of chiral WS₂-based nanotubes was investigated. All calculations presented in this study were performed using the density functional theory (DFT) and atomic gaussian type orbitals basis set. Nanotubes with chirality indices (8, 2), (12, 3), (24, 6) and (36, 9) corresponding to diameters of 10.68 Å, 14.90 Å, 28.26 Å and 41.90 Å, respectively, are examined. Our results reveal that for nanotubes with smaller diameters, the structure obtained through rolling from a slab is not optimal and undergoes spontaneous deformation. Furthermore, this study demonstrates that the nanotube torsion deformation leads to a reduction in the band gap. This observation suggests the potential for utilizing such torsional deformations to enhance the photocatalytic activity of the nanotubes. Full article

(This article belongs to the Section Theory and Simulation of Nanostructures)

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Open AccessArticle

Terbium Removal from Aqueous Solutions Using a In₂O₃ Nanoadsorbent and Arthrospira platensis Biomass

Amal H. Al-Bagawi

Nikita Yushin

Nasser Mohammed Hosny

Islam Gomaa

Sabah Ali

Warren Christopher Boyd

Haitham Kalil

and

Inga Zinicovscaia

Nanomaterials 2023, 13(19), 2698; https://doi.org/10.3390/nano13192698 - 03 Oct 2023

Abstract

Terbium is a rare-earth element with critical importance for industry. Two adsorbents of different origin, In₂O₃ nanoparticles and the biological sorbent Arthrospira platensis, were applied for terbium removal from aqueous solutions. Several analytical techniques, including X-ray diffraction, Fourier-transform infrared spectroscopy, and scanning electron microscopy, were employed to characterize the adsorbents. The effect of time, pH, and terbium concentration on the adsorption efficiency was evaluated. For both adsorbents, adsorption efficiency was shown to be dependent on the time of interaction and the pH of the solution. Maximum removal of terbium by Arthrospira platensis was attained at pH 3.0 and by In₂O₃ at pH 4.0–7.0, both after 3 min of interaction. Several equilibrium (Langmuir, Freundlich, and Temkin) and kinetics (pseudo-first order, pseudo-second order, and Elovich) models were applied to describe the adsorption. The maximum adsorption capacity was calculated from the Langmuir model as 212 mg/g for Arthrospira platensis and 94.7 mg/g for the In₂O₃ nanoadsorbent. The studied adsorbents can be regarded as potential candidates for terbium recovery from wastewater. Full article

(This article belongs to the Special Issue Nano-Adsorbents for the Removal of Heavy Metals and Dyes)

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Open AccessArticle

Polyoxometalate-Decorated Gold Nanoparticles Inhibit β-Amyloid Aggregation and Cross the Blood–Brain Barrier in a µphysiological Model

and

Nanomaterials 2023, 13(19), 2697; https://doi.org/10.3390/nano13192697 - 03 Oct 2023

Abstract

Alzheimer’s disease is characterized by a combination of several neuropathological hallmarks, such as extracellular aggregates of beta amyloid (Aβ). Numerous alternatives have been studied for inhibiting Aβ aggregation but, at this time, there are no effective treatments available. Here, we developed the tri-component nanohybrid system AuNPs@POM@PEG based on gold nanoparticles (AuNPs) covered with polyoxometalates (POMs) and polyethylene glycol (PEG). In this work, AuNPs@POM@PEG demonstrated the inhibition of the formation of amyloid fibrils, showing a 75% decrease in Aβ aggregation in vitro. As it is a potential candidate for the treatment of Alzheimer’s disease, we evaluated the cytotoxicity of AuNPs@POM@PEG and its ability to cross the blood–brain barrier (BBB). We achieved a stable nanosystem that is non-cytotoxic below 2.5 nM to human neurovascular cells. The brain permeability of AuNPs@POM@PEG was analyzed in an in vitro microphysiological model of the BBB (BBB-on-a-chip), containing 3D human neurovascular cell co-cultures and microfluidics. The results show that AuNPs@POM@PEG was able to cross the brain endothelial barrier in the chip and demonstrated that POM does not affect the barrier integrity, giving the green light to further studies into this system as a nanotherapeutic. Full article

(This article belongs to the Special Issue New Advances in Nanoparticles-Based Drug Delivery)

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Open AccessArticle

A Solar-Driven Oil–Water Separator with Fluorescence Sensing Performance

Xin Li

Wei Lin

Florian Ion Tiberiu Petrescu

and

Nanomaterials 2023, 13(19), 2696; https://doi.org/10.3390/nano13192696 - 03 Oct 2023

Abstract

Presently, the separation of oil and water through functional membranes inevitably entails either inefficient gravity-driven processes or energy-intensive vacuum pressure mechanisms. This study introduces an innovative photothermal evaporator that uses solar energy to drive oil–water separation while concurrently facilitating the detection of Fe³⁺ in wastewater. First, by alkali delignification, small holes were formed on the side wall of the large size tubular channel in the direction of wood growth. Subsequently, superhydrophilic SiO₂ nanoparticles were in situ assembled onto the sidewalls of the tubular channels. Finally, carbon quantum dots were deposited by spin-coating on the surface of the evaporator, paralleling the growth direction of the wood. During the photothermal evaporation process, the tubular channels with small holes in the side wall parallel the bulk water, which not only ensures the effective water supply to the photothermal surface but also reduces the heat loss caused by water reflux on the photothermal surface. The superhydrophilic SiO₂ nanoparticles confer both hydrophilic and oleophobic properties to the evaporator, preventing the accumulation of minute oil droplets within the device and achieving sustained and stable oil–water separation over extended periods. These carbon quantum dots exhibit capabilities for both photothermal conversion and fluorescence transmission. This photothermal evaporator achieves an evaporation rate as high as 2.3 kg m⁻² h⁻¹ in the oil–water separation process, and it has the ability to detect Fe³⁺ concentrations in wastewater as low as 10⁻⁹ M. Full article

(This article belongs to the Special Issue Nanostructured Materials for Energy Applications)

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Open AccessFeature PaperArticle

Multiscale Porous Carbon Materials by In Situ Growth of Metal–Organic Framework in the Micro-Channel of Delignified Wood for High-Performance Water Purification

and

Nanomaterials 2023, 13(19), 2695; https://doi.org/10.3390/nano13192695 - 03 Oct 2023

Abstract

Porous carbon materials are suitable as highly efficient adsorbents for the treatment of organic pollutants in wastewater. In this study, we developed multiscale porous and heteroatom (O, N)-doped activated carbon aerogels (CAs) based on mesoporous zeolitic imidazolate framework-8 (ZIF-8) nanocrystals and wood using 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) oxidation, in situ synthesis, and carbonization/activation. The surface carboxyl groups in a TEMPO-oxidized wood (TW) can provide considerably large nucleation sites for ZIF-8. Consequently, ZIF-8, with excellent porosity, was successfully loaded into the TW via in situ growth to enhance the specific surface area and enable heteroatom doping. Thereafter, the ZIF-8-loaded TW was subjected to a direct carbonization/activation process, and the obtained activated CA, denoted as ZIF-8/TW-CA, exhibited a highly interconnected porous structure containing multiscale (micro, meso, and macro) pores. Additionally, the resultant ZIF-8/TW-CA exhibited a low density, high specific surface area, and excellent organic dye adsorption capacity of 56.0 mg cm⁻³, 785.8 m² g⁻¹, and 169.4 mg g⁻¹, respectively. Given its sustainable, scalable, and low-cost wood platform, the proposed high-performance CA is expected to enable the substantial expansion of strategies for environmental protection, energy storage, and catalysis. Full article

(This article belongs to the Topic Porous Materials for Energy and Environment Applications)

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Open AccessEditorial

Functional Nanomaterials for Optoelectronics and Photocatalysis

Protima Rauwel

and

Erwan Rauwel

Nanomaterials 2023, 13(19), 2694; https://doi.org/10.3390/nano13192694 - 03 Oct 2023

Abstract

The present energy crisis has encouraged the use of energy-efficient devices and green energy sources [...] Full article

(This article belongs to the Section Nanophotonics Materials and Devices)

Open AccessArticle

Preparation of Dispersed Copper(II) Oxide Nanosuspensions as Precursor for Femtosecond Reductive Laser Sintering by High-Energy Ball Milling

Kay Bischoff

Cemal Esen

and

Ralf Hellmann

Nanomaterials 2023, 13(19), 2693; https://doi.org/10.3390/nano13192693 - 02 Oct 2023

Abstract

This contribution demonstrates and discusses the preparation of finely dispersed copper(II) oxide nanosuspensions as precursors for reductive laser sintering (RLS). Since the presence of agglomerates interferes with the various RLS sub-processes, fine dispersion is required, and oversized particles must be identified by a measurement methodology. Aside from the established method of scanning electron microscopy for imaging individual dried particles, this work applies the holistic and statistically more significant laser diffraction in combination with dynamic image analysis in wet dispersion. In addition to direct ultrasonic homogenization, high-energy ball milling is introduced for RLS, to produce stable nanosuspensions with a high fine fraction, and, above all, the absence of oversize particles. Whereas ultrasonic dispersion stagnates at particle sizes between 500

n

m

and 20

μ m

, even after 8 h, milled suspension contains a high proportion of finest particles with diameters below 100

n

m

, no agglomerates larger than 1

μ m

and a trimodal particle size distribution with the median at 50

n

m

already, after 100

\min

of milling. The precursor layers produced by doctor blade coating are examined for their quality by laser scanning microscopy. The surface roughness of such a dry film can be reduced from 1.26

μ m

to 88

n

m

by milling. Finally, the novel precursor is used for femtosecond RLS, to produce homogeneous, high-quality copper layers with a sheet resistance of

0.28

Ω

/sq and a copper mass concentration of 94.2%. Full article

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Open AccessArticle

Hybrid Pressure Sensor Based on Carbon Nano-Onions and Hierarchical Microstructures with Synergistic Enhancement Mechanism for Multi-Parameter Sleep Monitoring

and

Nanomaterials 2023, 13(19), 2692; https://doi.org/10.3390/nano13192692 - 01 Oct 2023

Abstract

With the existing pressure sensors, it is difficult to achieve the unification of wide pressure response range and high sensitivity. Furthermore, the preparation of pressure sensors with excellent performance for sleep health monitoring has become a research difficulty. In this paper, based on material and microstructure synergistic enhancement mechanism, a hybrid pressure sensor (HPS) integrating triboelectric pressure sensor (TPS) and piezoelectric pressure sensor (PPS) is proposed. For the TPS, a simple, low-cost, and structurally controllable microstructure preparation method is proposed in order to investigate the effect of carbon nano-onions (CNOs) and hierarchical composite microstructures on the electrical properties of CNOs@Ecoflex. The PPS is used to broaden the pressure response range and reduce the pressure detection limit of HPS. It has been experimentally demonstrated that the HPS has a high sensitivity of 2.46 V/10⁴ Pa (50–600 kPa) and a wide response range of up to 1200 kPa. Moreover, the HPS has a low detection limit (10 kPa), a high stability (over 100,000 cycles), and a fast response time. The sleep monitoring system constructed based on HPS shows remarkable performance in breathing state recognition and sleeping posture supervisory control, which will exhibit enormous potential in areas such as sleep health monitoring and potential disease prediction. Full article

(This article belongs to the Topic Advanced Nanomaterials for Sensing Applications)

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Open AccessArticle

Analysis of Hazy Ga- and Zr-Co-Doped Zinc Oxide Films Prepared with Atmospheric Pressure Plasma Jet Systems

and

Nanomaterials 2023, 13(19), 2691; https://doi.org/10.3390/nano13192691 - 01 Oct 2023

Abstract

Co-doped ZnO thin films have attracted much attention in the field of transparent conductive oxides (TCOs) in solar cells, displays, and other transparent electronics. Unlike conventional single-doped ZnO, co-doped ZnO utilizes two different dopant elements, offering enhanced electrical properties and more controllable optical properties, including transmittance and haze; however, most previous studies focused on the electrical properties, with less attention paid to obtaining high haze using co-doping. Here, we prepare high-haze Ga- and Zr-co-doped ZnO (GZO:Zr or ZGZO) using atmospheric pressure plasma jet (APPJ) systems. We conduct a detailed analysis to examine the interplay between Zr concentrations and film properties. UV-Vis spectroscopy shows a remarkable haze factor increase of 7.19% to 34.8% (+384%) for the films prepared with 2 at% Zr and 8 at% Ga precursor concentrations. EDS analysis reveals Zr accumulation on larger and smaller particles, while SIMS links particle abundance to impurity uptake and altered electrical properties. XPS identifies Zr mainly as ZrO₂ because of lattice stress from Zr doping, forming clusters at lattice boundaries and corroborating the SEM findings. Our work presents a new way to fabricate Ga- and Zr-co-doped ZnO for applications that require low electrical resistivity, high visible transparency, and high haze. Full article

(This article belongs to the Special Issue Nanomaterials and Nanofabrication for Solar Cells and Energy Harvesting)

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Open AccessArticle

An Evaluation of Experimental Calcium Ion-Leachable Nanocomposite Glass Ionomer Cements

Ioannis Tsolianos

Alexandros K. Nikolaidis

Elisabeth A. Koulaouzidou

and

Dimitris S. Achilias

Nanomaterials 2023, 13(19), 2690; https://doi.org/10.3390/nano13192690 - 30 Sep 2023

Abstract

Glass ionomer cements (GICs) are among the main restorative dental materials used broadly in daily clinical practice. The incorporation of clay nanoparticles as reinforcing agents is one potential approach to improving GIC properties. This study aims to investigate whether the incorporation of calcium-modified clay (Ca-clay) nanoparticles in conventional GICs alters their structural characteristics, along with their physicochemical and mechanical properties. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses were performed to assess the surface characterization of GIC nanocomposites, whereas a setting reaction was carried out via an attenuated total reflection Fourier transform infrared spectrometer (ATR-FTIR). A universal testing machine was used for compression tests, while calcium ion release was quantified using inductively coupled plasma optical emission spectrometry (ICP-OES). GIC composite groups reinforced with Ca-clay were found to release a fine amount of calcium ions (5.06–9.91 ppm), with the setting reaction being unaffected for low Ca-clay loadings. The median compressive strength of 3 wt% in the Ca-clay group (68.97 MPa) was nearly doubled compared to that of the control group (33.65 MPa). The incorporation of Ca-clay nanoparticles in GICs offers a promising alternative among dental restorative materials regarding their chemical and mechanical properties. Full article

(This article belongs to the Special Issue Nanotechnology in Dentistry)

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Open AccessArticle

Carbon Nanofibers Decorated by MoS₂ Nanosheets with Tunable Quantity as Self-Supporting Anode for High-Performance Lithium Ion Batteries

and

Nanomaterials 2023, 13(19), 2689; https://doi.org/10.3390/nano13192689 - 30 Sep 2023

Abstract

Two-dimensional molybdenum disulfide (MoS₂) is considered as a highly promising anode material for lithium-ion batteries (LIBs) due to its unique layer structure, large plane spacing, and high theoretical specific capacity; however, the overlap of MoS₂ nanosheets and inherently low electrical conductivity lead to rapid capacity decay, resulting in poor cycling stability and low multiplicative performance. This severely limits its practical application in LIBs. To overcome the above problems, composite fibers with a core//sheath structure have been designed and fabricated. The sheath moiety of MoS₂ nanosheets is uniformly anchored by the hydrothermal treatment of the axial of carbon nanofibers derived from an electrospinning method (CNFs//MoS₂). The quantity of the MoS₂ nanosheets on the CNFs substrates can be tuned by controlling the amount of utilized thiourea precursor. The influence of the MoS₂ nanosheets on the electrochemical properties of the composite fibers has been investigated. The synergistic effect between MoS₂ and carbon nanofibers can enhance their electrical conductivity and ionic reversibility as an anode for LIBs. The composite fibers deliver a high reversible capacity of 866.5 mA h g⁻¹ after 200 cycles at a current density of 0.5 A g⁻¹ and maintain a capacity of 703.3 mA h g⁻¹ after a long cycle of 500 charge–discharge processes at 1 A g⁻¹. Full article

(This article belongs to the Topic Advanced Nanomaterials for Lithium-Ion Batteries)

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Open AccessArticle

Energy Landscape of Relaxation and Interaction of an Amino Acid, Glutamine (L), on Pristine and Au/Ag/Cu-Doped TiO₂ Surfaces

Dušica Jovanović

Johann Christian Schön

and

Nanomaterials 2023, 13(19), 2688; https://doi.org/10.3390/nano13192688 - 30 Sep 2023

Abstract

Studying the interaction of inorganic systems with organic ones is a highly important avenue for finding new drugs and treatment methods. Tumor cells show an increased demand for amino acids due to their rapid proliferation; thus, targeting their metabolism is becoming a potential oncological therapeutic strategy. One of the inorganic materials that show antitumor properties is titanium dioxide, while its doping was found to enhance interactions with biological systems. Thus, in this study, we investigated the energy landscape of glutamine (L), an amino acid, on pristine and doped TiO₂ surfaces. We first locally optimized 2D-slab structures of pristine and Au/Ag/Cu-doped anatase (001 and 101 surfaces) and similarly optimized a single molecule of glutamine in vacuum. Next, we placed the pre-optimized glutamine molecule in various orientations and on a variety of locations onto the relaxed substrate surfaces (in vacuum) and performed ab initio relaxations of the molecule on the substrate slabs. We employed the DFT method with a GGA-PBE functional implemented in the Quantum Espresso code. Comparisons of the optimized conformations and electronic structures of the amino acid in vacuum and on the surfaces yield useful insights into various biological processes. Full article

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Open AccessArticle

Radiolabeling of Micro-/Nanoplastics via In-Diffusion

and

Nanomaterials 2023, 13(19), 2687; https://doi.org/10.3390/nano13192687 - 30 Sep 2023

Abstract

Micro- and nanoplastics are emerging pollutants with a concerning persistence in the environment. Research into their environmental impact requires addressing challenges related to sensitively and selectively detecting them in complex ecological media. One solution with great potential for alleviating these issues is using radiolabeling strategies. Here, we report the successful introduction of a ⁶⁴Cu radiotracer into common microplastics, namely polyethylene, polyethylene terephthalate, polystyrene, polyamide, and polyvinylidene dichloride, which allows the sensitive detection of mere nanograms of substance. Utilizing a Hansen Solubility Parameter screening, we developed a swelling and in-diffusion process for tetraphenylporphyrin-complexed ⁶⁴Cu, which permits one-pot labeling of polymer particles. Full article

(This article belongs to the Section Environmental Nanoscience and Nanotechnology)

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Open AccessArticle

Doping Effects of Carbon Nanotubes and Graphene on the Flexural Properties and Tribological Performance of Needle-Punched Carbon/Carbon Composites Prepared by Liquid-Phase Impregnation

and

Nanomaterials 2023, 13(19), 2686; https://doi.org/10.3390/nano13192686 - 30 Sep 2023

Abstract

The main goal of this study is to investigate the doping effects of carbon nanotubes (CNTs) and graphene on the needle-punched carbon/carbon (C/C) composites that are prepared by liquid-phase impregnation. In order to achieve, for the C/C composites, the purposes of high flexural strength, stable friction coefficient, low weight loss, and high thermal conductivity, our primary concern is to examine the flexural properties and the tribological performance, and then to explore a little further into the influence on thermal conductivity. In this study, carbon fiber preforms were first fabricated by needle-punched carbon-fiber cloth, and then liquid-phase phenolic resin, doped with different proportions of carbon nanotubes and graphene, was used as the impregnation solution to carry out multiple densification (impregnation–carbonization) cycles and fabricate various C/C composites. The main purpose was to probe into the doping effects of the CNTs and graphene, added to the impregnation solution, on the properties of C/C composites. The experimental results show that the addition of CNTs and graphene can improve the heat conductivity, flexural properties, and tribological performance of C/C composites, and the impact on these properties is more significant with the addition. Furthermore, the properties of graphene-doped C/C specimens are better than those of CNT-doped C/C specimens. Full article

(This article belongs to the Special Issue Graphene and Carbon Nanotube Ceramic Matrix Composites)

Open AccessArticle

Influences of Cu Doping on the Microstructure, Optical and Resistance Switching Properties of Zinc OxideThin Films

and

Nanomaterials 2023, 13(19), 2685; https://doi.org/10.3390/nano13192685 - 30 Sep 2023

Abstract

Copper-doped zinc oxide films (Zn_1−xCu_xO) (x = 0, 2%, 4%, 6%) were fabricated on conductive substrates using the sol-gel process. The crystal structure, optical and resistive switching properties of Zn_1−xCu_xO films are studied and discussed. RRAM is made using Zn_1−xCu_xO as the resistive layer. The results show that the (002) peak intensity and grain size of Zn_1−xCu_xOfilms increase from 0 to 6%. In addition, PL spectroscopy shows that the oxygen vacancy defect density of Zn_1−xCu_xO films also increases with the increase in Cu. The improved resistive switching performance of the RRAM device can be attributed to the formation of conductive filaments and the destruction of more oxygen vacancies in the Zn_1−xCu_xO film. Consequently, the RRAM device exhibits a higher low resistance state to high resistance state ratio and an HRS state of higher resistance value. Full article

(This article belongs to the Special Issue Nano-Structured Thin Films: Growth, Characteristics, and Application)

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Open AccessReview

Physiological Functions of Carbon Dots and Their Applications in Agriculture: A Review

Guohui Li

Jiwei Xu

and

Ke Xu

Nanomaterials 2023, 13(19), 2684; https://doi.org/10.3390/nano13192684 - 30 Sep 2023

Abstract

Carbon dots are carbon-based nanoparticles, which have the characteristics of a simple preparation process, photoluminescence, biocompatibility, an adjustable surface function, water solubility, and low-level toxicity. They are widely used in biological applications, such as imaging, biosensing, photocatalysis, and molecular transfer. They have also aroused great interest among researchers in agriculture, and there has been significant progress in improving crop growth and production. This review presents the physiological functions of carbon dots for crop growth and development, photosynthesis, water and nutrient absorption, and abiotic stress resistance and their applications in improving the ecological environment and agriculture as biosensors, and future application prospects and research directions of carbon dots in agriculture. Full article

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