Nanomaterials

10 pages, 2303 KiB

Open AccessArticle

ZnO Nanorods Grown on Rhombic ZnO Microrods for Enhanced Photocatalytic Activity

by Yufu Zhu, Jiaying Yan, Lei Zhou and Liangdong Feng

Nanomaterials 2022, 12(17), 3085; https://doi.org/10.3390/nano12173085 - 05 Sep 2022

Cited by 1 | Viewed by 1516

In this paper, the formation of rhombic ZnO microrods surrounded by ZnO nanorods was realized on the surfaces of zinc foils using a hydrothermal method. The photocatalytic degradation of Rhodamine B solution was used to test the photocatalytic performance of the prepared samples. [...] Read more.

In this paper, the formation of rhombic ZnO microrods surrounded by ZnO nanorods was realized on the surfaces of zinc foils using a hydrothermal method. The photocatalytic degradation of Rhodamine B solution was used to test the photocatalytic performance of the prepared samples. Compared with the rhombic Zn(OH)F and ZnO microrods grown on zinc foils, the hierarchical micro/nanostructures formed by ZnO nanorods surrounding the surfaces of rhombic ZnO microrods have better photocatalytic performance. The experimental results are mainly due to the fact that the hierarchical ZnO micro/nanostructures formed by ZnO nanorods surrounding the surface of the rhombic ZnO microrods have a larger surface area compared with the rhombic Zn(OH)F and ZnO microrods. More importantly, the photocatalytic circulation experiments indicate that ZnO nanorods grown on rhombic ZnO microrods can be recycled and have a relatively stable photocatalytic performance. Full article

(This article belongs to the Special Issue Nanomaterials for Environmental Protection)

► Show Figures

Figure 1

10 pages, 1759 KiB

Open AccessArticle

Organic Photodetectors with Extended Spectral Response Range Assisted by Plasmonic Hot-Electron Injection

by Aiping Zhai, Chenjie Zhao, Deng Pan, Shilei Zhu, Wenyan Wang, Ting Ji, Guohui Li, Rong Wen, Ye Zhang, Yuying Hao and Yanxia Cui

Nanomaterials 2022, 12(17), 3084; https://doi.org/10.3390/nano12173084 - 05 Sep 2022

Viewed by 1739

Abstract

Organic photodetectors (OPDs) have aroused intensive attention for signal detection in industrial and scientific applications due to their advantages including low cost, mechanical flexibility, and large-area fabrication. As one of the most common organic light-emitting materials, 8-hydroxyquinolinato aluminum (Alq₃) has an [...] Read more.

Organic photodetectors (OPDs) have aroused intensive attention for signal detection in industrial and scientific applications due to their advantages including low cost, mechanical flexibility, and large-area fabrication. As one of the most common organic light-emitting materials, 8-hydroxyquinolinato aluminum (Alq₃) has an absorption wavelength edge of 460 nm. Here, through the introduction of Ag nanoparticles (Ag NPs), the spectral response range of the Alq₃-based OPD was successfully extended to the near-infrared range. It was found that introducing Ag NPs can induce rich plasmonic resonances, generating plenty of hot electrons, which could be injected into Alq₃ and then be collected. Moreover, as a by-product of introducing Ag NPs, the dark current was suppressed by around two orders of magnitude by forming a Schottky junction on the cathode side. These two effects in combination produced photoelectric signals with significant contrasts at wavelengths beyond the Alq₃ absorption band. It was found that the OPD with Ag NPs can stably generate electric signals under illumination by pulsed 850 nm LED, while the output of the reference device included no signal. Our work contributes to the development of low-cost, broadband OPDs for applications in flexible electronics, bio-imaging sensors, etc. Full article

► Show Figures

Graphical abstract

14 pages, 4499 KiB

Open AccessArticle

Circularly Polarized Antenna Array with Decoupled Quad Vortex Beams

by Shuo Xu, He-Xiu Xu, Yanzhao Wang, Jian Xu, Chaohui Wang, Zhichao Pang and Huiling Luo

Nanomaterials 2022, 12(17), 3083; https://doi.org/10.3390/nano12173083 - 05 Sep 2022

Cited by 3 | Viewed by 1541

Abstract

Achieving multiple vortex beams with different modes in a planar microstrip array is pivotal, yet still extremely challenging. Here, a hybrid method combining both Pancharatnam−Berry (PB) phase that is induced by the rotation phase and excitation phase of a feeding line has been [...] Read more.

Achieving multiple vortex beams with different modes in a planar microstrip array is pivotal, yet still extremely challenging. Here, a hybrid method combining both Pancharatnam−Berry (PB) phase that is induced by the rotation phase and excitation phase of a feeding line has been proposed for decoupling two orthogonal circularly polarized vortex beams. Theoretical analysis is derived for array design to generate quad vortex beams with different directions and an arbitrary number of topological charges. On this basis, two 8 × 8 planar arrays were theoretically designed in an X band, which are with topological charges of l₁ = −1, l₂ = 1, l₃ = −1, and l₄ = 1 in Case I and topological charges of l₁ = −1, l₂ = 1, l₃ = −1, and l₄ = 1 in Case II. To further verify the above theory, the planar array in Case I is fabricated and analyzed experimentally. Dual-LP beams are realized by using rectangular patch elements with two orthogonally distributed feeding networks on different layers based on two types of feeding: proximity coupling and aperture coupling. Both the numerical simulation and experimental measurement results are in good agreement and showcase the corresponding quad-vortex-beam characteristics within 8~12 GHz. The array achieves a measured S₁₁ < −10 dB and S₂₂ < −10 dB bandwidth of more than 33.4% and 29.2%, respectively. In addition, the isolation between two ports is better than −28 dB. Our strategy provides a promising way to achieve large capacity and high integration, which is of great benefit to wireless and radar communication systems. Full article

(This article belongs to the Special Issue Metasurfaces for Photonic Devices: Theory and Applications)

► Show Figures

Figure 1

9 pages, 4770 KiB

Open AccessArticle

The 3.4 GHz BAW RF Filter Based on Single Crystal AlN Resonator for 5G Application

by Rui Ding, Weipeng Xuan, Shurong Dong, Biao Zhang, Feng Gao, Gang Liu, Zichao Zhang, Hao Jin and Jikui Luo

Nanomaterials 2022, 12(17), 3082; https://doi.org/10.3390/nano12173082 - 05 Sep 2022

Cited by 10 | Viewed by 2929

Abstract

To meet the stringent requirements of 5G communication, we proposed a high-performance bulk acoustic wave (BAW) filter based on single crystal AlN piezoelectric films on a SiC substrate. The fabrication of the BAW filter is compatible with the GaN high electron mobility transistor [...] Read more.

To meet the stringent requirements of 5G communication, we proposed a high-performance bulk acoustic wave (BAW) filter based on single crystal AlN piezoelectric films on a SiC substrate. The fabrication of the BAW filter is compatible with the GaN high electron mobility transistor (HEMT) process, enabling the implementation of the integration of the BAW device and high-performance monolithic microwave integrated circuit (MMIC). The single crystal AlN piezoelectric film with 650-nm thickness was epitaxially grown on the SiC substrate by Metal Organic Chemical Vapor Deposition (MOCVD). After wafer bonding and substrate removal, the single crystal AlN film with electrode layers was transferred to another SiC wafer to form an air gap type BAW. Testing results showed that the fabricated resonators have a maximum Q-factor up to 837 at 3.3 GHz resonant frequency and electromechanical coupling coefficient up to 7.2%. Ladder-type filters were developed to verify the capabilities of the BAW and process, which has a center frequency of 3.38 GHz with 160 MHz 3 dB bandwidth. The filter achieved a minimum 1.5 dB insertion loss and more than 31 dB out-of-band rejection. The high performance of the filters is attributed to the high crystallinity and low defects of epitaxial single crystal AlN films. Full article

(This article belongs to the Section Nanofabrication and Nanomanufacturing)

► Show Figures

Graphical abstract

15 pages, 3780 KiB

Open AccessArticle

Synthesis of Porous Hierarchical In₂O₃ Nanostructures with High Methane Sensing Property at Low Working Temperature

by Huiju Zhang, Jiangnan Chang, Yan Wang and Jianliang Cao

Nanomaterials 2022, 12(17), 3081; https://doi.org/10.3390/nano12173081 - 05 Sep 2022

Cited by 2 | Viewed by 1421

Abstract

Different hierarchical porous In₂O₃ nanostructures were synthesized by regulating the hydrothermal time and combining it with a self-pore-forming method. The gas-sensing test results show that the response of the sensor based on In₂O₃ obtained after hydrothermal reaction [...] Read more.

Different hierarchical porous In₂O₃ nanostructures were synthesized by regulating the hydrothermal time and combining it with a self-pore-forming method. The gas-sensing test results show that the response of the sensor based on In₂O₃ obtained after hydrothermal reaction for 48 h is about 10.4 to 500 ppm methane. Meanwhile, it possesses good reproducibility, stability, selectivity and moisture resistance as well as a good exponential linear relationship between the response to methane and its concentration. In particular, the sensor based on In₂O₃ can detect a wide range of methane (10~2000 ppm) at near-room temperature (30 °C). The excellent methane sensitivity of the In₂O₃ sensor is mainly due to its unique nanostructure, which has the advantages of both porous and hierarchical structures. Combined with the DFT calculation, it is considered that the sensitive mechanism is mainly controlled by the surface adsorbed oxygen model. This work provides a feasible strategy for enhancing the gas sensitivity of In₂O₃ toward methane at low temperatures. Full article

(This article belongs to the Special Issue Advanced Nanomaterials and Nanodevices for VOCs Gas Sensor)

► Show Figures

Figure 1

16 pages, 5651 KiB

Open AccessArticle

Detailed Investigation of Factors Affecting the Synthesis of SiO₂@Au for the Enhancement of Raman Spectroscopy

by Nguyen Thi Phuong Thao, Loc Ton-That, Cong-Thuan Dang and Jan Nedoma

Nanomaterials 2022, 12(17), 3080; https://doi.org/10.3390/nano12173080 - 05 Sep 2022

Cited by 2 | Viewed by 2464

Abstract

The reaction time, temperature, ratio of precursors, and concentration of sodium citrate are known as the main factors that affect the direct synthesis process of SiO₂@Au based on the chemical reaction of HAuCl4 and sodium citrate. Hence, we investigated, in detail, [...] Read more.

The reaction time, temperature, ratio of precursors, and concentration of sodium citrate are known as the main factors that affect the direct synthesis process of SiO₂@Au based on the chemical reaction of HAuCl4 and sodium citrate. Hence, we investigated, in detail, and observed that these factors played a crucial role in determining the shape and size of synthesized nanoparticles. The significant enhancement of the SERS signal corresponding to the fabrication conditions is an existing challenge. Our study results show that the optimal reaction conditions for the fabrication of SiO₂@Au are a 1:21 ratio of HAuCl₄ to sodium citrate, with an initial concentration of sodium citrate of 4.2 mM, and a reaction time lasting longer than 6 h at a temperature of 80 °C. Under optimal conditions, our synthesis process result is SiO₂@Au nanoparticles with a diameter of approximately 350 nm. In particular, the considerable enhancement of Raman intensities of SiO₂@Au compared to SiO₂ particles was examined. Full article

► Show Figures

Figure 1

15 pages, 6291 KiB

Open AccessArticle

Enhancing the Efficiency of Perovskite Solar Cells through Interface Engineering with MoS₂ Quantum Dots

by Zhao Luo, Tan Guo, Chen Wang, Jifan Zou, Jianxun Wang, Wei Dong, Jing Li, Wei Zhang, Xiaoyu Zhang and Weitao Zheng

Nanomaterials 2022, 12(17), 3079; https://doi.org/10.3390/nano12173079 - 05 Sep 2022

Cited by 11 | Viewed by 2297

Abstract

The interface of perovskite solar cells (PSCs) determines their power conversion efficiency (PCE). Here, the buried bottom surface of a perovskite film is efficiently passivated by using MoS₂ quantum dots. The perovskite films prepared on top of MoS₂-assisted substrates show [...] Read more.

The interface of perovskite solar cells (PSCs) determines their power conversion efficiency (PCE). Here, the buried bottom surface of a perovskite film is efficiently passivated by using MoS₂ quantum dots. The perovskite films prepared on top of MoS₂-assisted substrates show enhanced crystallinity, as evidenced by improved photoluminescence and a prolonged emission lifetime. MoS₂ quantum dots with a large bandgap of 2.68 eV not only facilitate hole collection but also prevent the photogenerated electrons from flowing to the hole transport layer. Overall promotion leads to decreased trap density and an enhanced built-in electric field, thus increasing the device PCE from 17.87% to 19.95%. Full article

(This article belongs to the Special Issue Luminescent Colloidal Nanocrystals)

► Show Figures

Graphical abstract

18 pages, 6646 KiB

Open AccessArticle

Enhancing the Melting Process of Shell-and-Tube PCM Thermal Energy Storage Unit Using Modified Tube Design

by Aissa Abderrahmane, Naef A. A. Qasem, Abed Mourad, Mohammad Al-Khaleel, Zafar Said, Kamel Guedri, Obai Younis and Riadh Marzouki

Nanomaterials 2022, 12(17), 3078; https://doi.org/10.3390/nano12173078 - 05 Sep 2022

Cited by 15 | Viewed by 1850

Abstract

Recently, phase change materials (PCMs) have gained great attention from engineers and researchers due to their exceptional properties for thermal energy storing, which would effectively aid in reducing carbon footprint and support the global transition of using renewable energy. The current research attempts [...] Read more.

Recently, phase change materials (PCMs) have gained great attention from engineers and researchers due to their exceptional properties for thermal energy storing, which would effectively aid in reducing carbon footprint and support the global transition of using renewable energy. The current research attempts to enhance the thermal performance of a shell-and-tube heat exchanger by means of using PCM and a modified tube design. The enthalpy–porosity method is employed for modelling the phase change. Paraffin wax is treated as PCM and poured within the annulus; the annulus comprises a circular shell and a fined wavy (trefoil-shaped) tube. In addition, copper nanoparticles are incorporated with the base PCM to enhance the thermal conductivity and melting rate. Effects of many factors, including nanoparticle concentration, the orientation of the interior wavy tube, and the fin length, were examined. Results obtained from the current model imply that Cu nanoparticles added to PCM materials improve thermal and melting properties while reducing entropy formation. The highest results (27% decrease in melting time) are obtained when a concentration of nanoparticles of 8% is used. Additionally, the fins’ location is critical because fins with 45° inclination could achieve a 50% expedition in the melting process. Full article

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

► Show Figures

Figure 1

18 pages, 6810 KiB

Open AccessEditor’s ChoiceArticle

Pyridine vs. Imidazole Axial Ligation on Cobaloxime Grafted Graphene: Hydrogen Evolution Reaction Insights

by Ioanna K. Sideri, Georgios Charalambidis, Athanassios G. Coutsolelos, Raul Arenal and Nikos Tagmatarchis

Nanomaterials 2022, 12(17), 3077; https://doi.org/10.3390/nano12173077 - 05 Sep 2022

Cited by 7 | Viewed by 1559

Abstract

While cobaloximes have been protagonists in the molecular (photo)catalytic hydrogen evolution reaction field, researchers originally shed light on the catalytically active metallic center. However, the specific chemical environment of cobalt, including equatorial and axial ligation, has also a strong impact on the catalytic [...] Read more.

While cobaloximes have been protagonists in the molecular (photo)catalytic hydrogen evolution reaction field, researchers originally shed light on the catalytically active metallic center. However, the specific chemical environment of cobalt, including equatorial and axial ligation, has also a strong impact on the catalytic reaction. In this article, we aim to demonstrate how pyridine vs. imidazole axial ligation of a cobaloxime complex covalently grafted on graphene affects the hydrogen evolution reaction performance in realistic acidic conditions. While pyridine axial ligation mirrors a drastically superior electrocatalytic performance, imidazole exhibits a remarkable long-term stability. Full article

(This article belongs to the Special Issue Nanomaterials in Catalysis for Environmental and Energy Applications)

► Show Figures

Graphical abstract

12 pages, 7098 KiB

Open AccessArticle

Experimental Study of the Jetting Behavior of High-Viscosity Nanosilver Inks in Inkjet-Based 3D Printing

by Xingzhi Xiao, Gang Li, Tingting Liu and Mingfei Gu

Nanomaterials 2022, 12(17), 3076; https://doi.org/10.3390/nano12173076 - 05 Sep 2022

Cited by 10 | Viewed by 2035

Abstract

Inkjet printing of high-viscosity (up to 10⁵ mPa·s) nanosilver inks is an interesting emerging technology to achieve the 3D fully printed fabrication of electronic products. The highly viscous force of the ink makes it impossible to achieve droplet ejection with the traditional [...] Read more.

Inkjet printing of high-viscosity (up to 10⁵ mPa·s) nanosilver inks is an interesting emerging technology to achieve the 3D fully printed fabrication of electronic products. The highly viscous force of the ink makes it impossible to achieve droplet ejection with the traditional piezoelectric-driven drop-on-demand inkjet method. In this study, a pneumatic needle jetting valve is adopted to provide sufficient driving force. A large number of high-viscosity inkjet printing tests are carried out, and the jetting behavior is recorded with a high-speed camera. Different jetting states are determined according to the recorded images, and the causes of their formation are revealed. Additionally, the effects of the operating pressure, preload angle, and fluid pressure on jetting states are elucidated. Furthermore, the jetting phase diagram is obtained with the characterization of the Reynolds number and the printable region is clarified. This provides a better understanding of high-viscosity inkjet printing and will promote the application of high-viscosity inkjet printing in 3D fully printed electronic products. Full article

► Show Figures

Figure 1

21 pages, 6605 KiB

Open AccessArticle

Curcumin and Capsaicin-Loaded Ag-Modified Mesoporous Silica Carriers: A New Alternative in Skin Treatment

by Ivalina Trendafilova, Ralitsa Chimshirova, Denitsa Momekova, Hristo Petkov, Neli Koseva, Penka Petrova and Margarita Popova

Nanomaterials 2022, 12(17), 3075; https://doi.org/10.3390/nano12173075 - 05 Sep 2022

Cited by 1 | Viewed by 1821

Abstract

Biologically active substances of natural origin offer a promising alternative in skin disease treatment in comparison to synthetic medications. The limiting factors for the efficient application of natural compounds, such as low water solubility and low bioavailability, can be easily overcome by the [...] Read more.

Biologically active substances of natural origin offer a promising alternative in skin disease treatment in comparison to synthetic medications. The limiting factors for the efficient application of natural compounds, such as low water solubility and low bioavailability, can be easily overcome by the development of suitable delivery systems. In this study, the exchange with the template procedure was used for the preparation ofa spherical silver-modified mesoporous silica nanocarrier. The initial and drug-loaded formulations are fully characterized by different physico-chemical methods. The incipient wetness impregnation method used to load health-promoting agents, curcumin, and capsaicin in Ag-modified carriers separately or in combinationresulted in high loading efficiency (up to 33 wt.%). The interaction between drugs and carriers was studied by ATR-FTIR spectroscopy. The release experiments of both active substances from the developed formulations were studied in buffers with pH 5.5, and showed improved solubility. Radical scavenging activity and ferric-reducing antioxidant power assays were successfully used for the evaluation of the antiradical and antioxidant capacity of the curcumin or/and capsaicin loaded on mesoporous carriers. Formulations containing a mixture of curcumin and capsaicin were characterized bypotentiation of their antiproliferative effect against maligning cells, and it was confirmed that the system for simultaneous delivery of both drugs has lower IC₅₀ values than the free substances.The antibacterial tests showed better activity of the obtained delivery systems in comparison with the pure curcumin and capsaicin. Considering the obtained results, it can be concluded that the obtained delivery systems are promising for potential dermal treatment. Full article

(This article belongs to the Special Issue Nanostructured Mesoporous and Zeolite-Based Materials)

► Show Figures

Figure 1

24 pages, 7658 KiB

Open AccessArticle

Ameliorative Effect of Pomegranate Peel Extract (PPE) on Hepatotoxicity Prompted by Iron Oxide Nanoparticles (Fe₂O₃-NPs) in Mice

by Yasmin M. Abd El-Aziz, Basma M. Hendam, Fawziah A. Al-Salmi, Safa H. Qahl, Eman H. Althubaiti, Fahmy G. Elsaid, Ali A. Shati, Nasser M. Hosny, Eman Fayad and Ali H. Abu Almaaty

Nanomaterials 2022, 12(17), 3074; https://doi.org/10.3390/nano12173074 - 04 Sep 2022

Cited by 3 | Viewed by 1569

Abstract

An evaluation of the ameliorative effect of pomegranate peel extract (PPE) in counteracting the toxicity of iron oxide nanoparticles (Fe₂O₃-NPs) that cause hepatic tissue damage is focused on herein. Forty male albino mice were haphazardly grouped into four groups [...] Read more.

An evaluation of the ameliorative effect of pomegranate peel extract (PPE) in counteracting the toxicity of iron oxide nanoparticles (Fe₂O₃-NPs) that cause hepatic tissue damage is focused on herein. Forty male albino mice were haphazardly grouped into four groups as follows: the first control group was orally gavage daily with physiological saline; the second group received 100 mg/kg of PPE by the oral route day after day; the third group received 30 mg/kg Fe₂O₃-NPs orally; and the fourth group received both PPE and Fe₂O₃-NPs by the oral route, the same as the second and third sets. Later, after the completion of the experiment, we collected the liver, blood, and bone marrow of bone specimens that were obtained for further laboratory tests. For instance, exposure to Fe₂O₃-NPs significantly altered serum antioxidant biomarkers by decreasing the levels of total antioxidant capacity (TAC), catalase (CAT), and glutathione s-transferase (GST). Additionally, it caused changes in the morphology of hepatocytes, hepatic sinusoids, and inflammatory Kupffer cells. Furthermore, they significantly elevated the number of chromosomal aberrations including gaps, breaks, deletions, fragments, polyploidies, and ring chromosomes. Moreover, they caused a significant overexpression of TIMP-1, TNF-α, and BAX mRNA levels. Finally, the use of PPE alleviates the toxicity of Fe₂O₃-NPs that were induced in the hepatic tissues of mice. It is concluded that PPE extract has mitigative roles against the damage induced by Fe₂O₃-NPs, as it serves as an antioxidant and hepatoprotective agent. The use of PPE as a modulator of Fe₂O₃-NPs’ hepatotoxicity could be considered as a pioneering method in the use of phytochemicals against the toxicity of nanoparticles. Full article

(This article belongs to the Section Biology and Medicines)

► Show Figures

Figure 1

9 pages, 1440 KiB

Open AccessArticle

Higher-Order Multiphoton Absorption Upconversion Lasing Based on ZnO/ZnMgO Multiple Quantum Wells

by Shushu Ma, Haiyuan Wei, Hai Zhu, Francis Chi-Chung Ling, Xianghu Wang and Shichen Su

Nanomaterials 2022, 12(17), 3073; https://doi.org/10.3390/nano12173073 - 04 Sep 2022

Viewed by 1513

Abstract

In the progress of nonlinear optics, multiphoton absorption (MPA) upconversion lasing enables many vital applications in bioimaging, three-dimensional optical data storage, and photodynamic therapy. Here, efficient four-photon absorption upconversion lasing from the ZnO/ZnMgO multiple quantum wells (MQWs) at room temperature is realized. Moreover, [...] Read more.

In the progress of nonlinear optics, multiphoton absorption (MPA) upconversion lasing enables many vital applications in bioimaging, three-dimensional optical data storage, and photodynamic therapy. Here, efficient four-photon absorption upconversion lasing from the ZnO/ZnMgO multiple quantum wells (MQWs) at room temperature is realized. Moreover, the MPA upconversion lasing and third-harmonic generation peak generated in the MQWs under the excitation of a femtosecond (fs) laser pulse were observed concurrently, and the essential differences between each other were studied comprehensively. Compared with the ZnO film, the upconversion lasing peak of the ZnO/ZnMgO MQWs exhibits a clear blue shift. In addition, the four-photon absorption upconversion photoluminescence (PL) intensity was enhanced in the MQWs/Au nanoparticles (NPs) by the metal-localized surface plasmons (LSPs). The work paves the way for short-wavelength lasers by taking advantage of the high stability and large exciton binding energy of the MQWs’ structures. Full article

► Show Figures

Figure 1

11 pages, 3030 KiB

Open AccessArticle

Electrospun Magnetic Ionic Liquid Based Electroactive Materials for Tissue Engineering Applications

by Liliana C. Fernandes, Rafaela M. Meira, Daniela M. Correia, Clarisse Ribeiro, Eduardo Fernandez, Carmen R. Tubio and Senentxu Lanceros-Méndez

Nanomaterials 2022, 12(17), 3072; https://doi.org/10.3390/nano12173072 - 04 Sep 2022

Cited by 1 | Viewed by 1489

Abstract

Functional electrospun fibers incorporating ionic liquids (ILs) present a novel approach in the development of active microenviroments due to their ability to respond to external magnetic fields without the addition of magnetic particles. In this context, this work reports on the development of [...] Read more.

Functional electrospun fibers incorporating ionic liquids (ILs) present a novel approach in the development of active microenviroments due to their ability to respond to external magnetic fields without the addition of magnetic particles. In this context, this work reports on the development of magnetically responsive magneto-ionic fibers based on the electroactive polymer poly(vinylidene fluoride) and the magnetic IL (MIL), bis(1-butyl-3-methylimidazolium) tetrathiocyanatocobaltate ([Bmim]₂[(SCN)₄Co]). The PVDF/MIL electrospun fibers were prepared incorporating 5, 10 and 15 wt.% of the MIL, showing that the inclusion of the MIL increases the polar β-phase content of the polymer from 79% to 94% and decreases the crystallinity of the fibers from 47% to 36%. Furthermore, the thermal stability of the fibers decreases with the incorporation of the MIL. The magnetization of the PVDF/MIL composite fibers is proportional to the MIL content and decreases with temperature. Finally, cytotoxicity assays show a decrease in cell viability with increasing the MIL content. Full article

(This article belongs to the Section Synthesis, Interfaces and Nanostructures)

► Show Figures

Figure 1

14 pages, 5263 KiB

Open AccessArticle

Highly Breathable and Abrasion-Resistant Membranes with Micro-/Nano-Channels for Eco-Friendly Moisture-Wicking Medical Textiles

by Yue Zhang, Xing Li, Hong-Yang Wang, Bo-Xiang Wang, Jia Li, De-Hong Cheng and Yan-Hua Lu

Nanomaterials 2022, 12(17), 3071; https://doi.org/10.3390/nano12173071 - 04 Sep 2022

Cited by 4 | Viewed by 2075

Abstract

One-way water transport is a predominant feature of comfortable textiles used in daily life. However, shortcomings related to the textiles include their poor breathability and durability. In this study, low-cost and eco-friendly PLA/low-melt (polylactic acid) LMPLA-thermoplastic polyurethane (TPU) membranes were fabricated through a [...] Read more.

One-way water transport is a predominant feature of comfortable textiles used in daily life. However, shortcomings related to the textiles include their poor breathability and durability. In this study, low-cost and eco-friendly PLA/low-melt (polylactic acid) LMPLA-thermoplastic polyurethane (TPU) membranes were fabricated through a needle punch/hot press and electrospinning method. The micro-/nano-channels, used for the first time, endowed the composite membranes with robust, breathable, moisture-permeable, and abrasion-resistant performance. By varying the nano- layer thickness, the resulting 16–40 μm membranes exhibited excellent one-way water transport, robust breathability and moisture permeability, and good abrasion resistance. Nano-layer thickness was found to be a critical performance factor, balancing comfort and protection. These results may be useful for developing low-cost, eco-friendly, and versatile protective products for medical application. Full article

(This article belongs to the Section Nanocomposite Materials)

► Show Figures

Figure 1

9 pages, 3908 KiB

Open AccessArticle

Plasmon-Enhanced Fluorescence Emission of an Electric Dipole Modulated by a Nanoscale Silver Hemisphere

by Jiangtao Lv, Minghui Chang, Qiongchan Gu, Yu Ying and Guangyuan Si

Nanomaterials 2022, 12(17), 3070; https://doi.org/10.3390/nano12173070 - 03 Sep 2022

Viewed by 1231

Abstract

The spontaneous emission of a fluorophore is altered by the surrounding electromagnetic field. Therefore, the radiation of the fluorophore can be engineered by inter-coupling with the nanoscale plasmons. This work proposes a nanoscale hemisphere structure that enhances the electric field and further modulates [...] Read more.

The spontaneous emission of a fluorophore is altered by the surrounding electromagnetic field. Therefore, the radiation of the fluorophore can be engineered by inter-coupling with the nanoscale plasmons. This work proposes a nanoscale hemisphere structure that enhances the electric field and further modulates its effects on fluorophores by adjusting the radius of the hemisphere. A full-wave simulation is carried out using the finite element method, and the radiation characteristics of the nanoscale hemisphere are studied in detail. Compared with free space, the structure has generated significant enhancement exceeding 30. Through curve fitting, the relationship between the enhanced peak wavelength and the radius of the hemisphere is obtained. Full article

(This article belongs to the Special Issue Nanophotonics: Plasmons, Lasers and Photonic Crystals)

► Show Figures

Figure 1

12 pages, 7774 KiB

Open AccessArticle

Preparation and Study of a Simple Three-Matrix Solid Electrolyte Membrane in Air

by Xinghua Liang, Xingtao Jiang, Linxiao Lan, Shuaibo Zeng, Meihong Huang and Dongxue Huang

Nanomaterials 2022, 12(17), 3069; https://doi.org/10.3390/nano12173069 - 03 Sep 2022

Cited by 3 | Viewed by 1408

Abstract

Solid-state lithium batteries have attracted much attention due to their special properties of high safety and high energy density. Among them, the polymer electrolyte membrane with high ionic conductivity and a wide electrochemical window is a key part to achieve stable cycling of [...] Read more.

Solid-state lithium batteries have attracted much attention due to their special properties of high safety and high energy density. Among them, the polymer electrolyte membrane with high ionic conductivity and a wide electrochemical window is a key part to achieve stable cycling of solid-state batteries. However, the low ionic conductivity and the high interfacial resistance limit its practical application. This work deals with the preparation of a composite solid electrolyte with high mechanical flexibility and non-flammability. Firstly, the crystallinity of the polymer is reduced, and the fluidity of Li⁺ between the polymer segments is improved by tertiary polymer polymerization. Then, lithium salt is added to form a solpolymer solution to provide Li⁺ and anion and then an inorganic solid electrolyte is added. As a result, the composite solid electrolyte has a Li⁺ conductivity (3.18 × 10⁻⁴ mS cm⁻¹). The (LiNi_0.5Mn_1.5O₄)LNMO/SPLL (PES-PVC-PVDF-LiBF₄-LAZTP)/Li battery has a capacity retention rate of 98.4% after 100 cycles, which is much higher than that without inorganic oxides. This research provides an important reference for developing all-solid-state batteries in the greenhouse. Full article

(This article belongs to the Special Issue Advances in Nano-Electrochemical Materials and Devices)

► Show Figures

Figure 1

22 pages, 11765 KiB

Open AccessArticle

Development of Ag-Doped ZnO Thin Films and Thermoluminescence (TLD) Characteristics for Radiation Technology

by Hammam Abdurabu Thabit, Norlaili A. Kabir, Abd Khamim Ismail, Shoroog Alraddadi, Abdullah Bafaqeer and Muneer Aziz Saleh

Nanomaterials 2022, 12(17), 3068; https://doi.org/10.3390/nano12173068 - 03 Sep 2022

Cited by 17 | Viewed by 2345

Abstract

This work examined the thermoluminescence dosimetry characteristics of Ag-doped ZnO thin films. The hydrothermal method was employed to synthesize Ag-doped ZnO thin films with variant molarity of Ag (0, 0.5, 1.0, 3.0, and 5.0 mol%). The structure, morphology, and optical characteristics were investigated [...] Read more.

This work examined the thermoluminescence dosimetry characteristics of Ag-doped ZnO thin films. The hydrothermal method was employed to synthesize Ag-doped ZnO thin films with variant molarity of Ag (0, 0.5, 1.0, 3.0, and 5.0 mol%). The structure, morphology, and optical characteristics were investigated using X-ray diffraction (XRD), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDX), photoluminescence (PL), and UV–vis spectrophotometers. The thermoluminescence characteristics were examined by exposing the samples to X-ray radiation. It was obtained that the highest TL intensity for Ag-doped ZnO thin films appeared to correspond to 0.5 mol% of Ag, when the films were exposed to X-ray radiation. The results further showed that the glow curve has a single peak at 240–325 °C, with its maximum at 270 °C, which corresponded to the heating rate of 5 °C/s. The results of the annealing procedures showed the best TL response was found at 400 °C and 30 min. The dose–response revealed a good linear up to 4 Gy. The proposed sensitivity was 1.8 times higher than the TLD 100 chips. The thermal fading was recorded at 8% for 1 Gy and 20% for 4 Gy in the first hour. After 45 days of irradiation, the signal loss was recorded at 32% and 40% for the cases of 1 Gy and 4 Gy, respectively. The obtained optical fading results confirmed that all samples’ stored signals were affected by the exposure to sunlight, which decreased up to 70% after 6 h. This new dosimeter exhibits good properties for radiation measurement, given its overgrowth (in terms of the glow curve) within 30 s (similar to the TLD 100 case), simple annealing procedure, and high sensitivity (two times that of the TLD 100). Full article

(This article belongs to the Special Issue Luminescence Nanomaterials and Applications)

► Show Figures

Figure 1

11 pages, 2792 KiB

Open AccessCommunication

Efficient Nanocrystal Photovoltaics with PTAA as Hole Transport Layer

by Ao Xu, Qichuan Huang, Kaiying Luo, Donghuan Qin, Wei Xu, Dan Wang and Lintao Hou

Nanomaterials 2022, 12(17), 3067; https://doi.org/10.3390/nano12173067 - 03 Sep 2022

Viewed by 1660

Abstract

The power conversion efficiency (PCE) of solution-processed CdTe nanocrystals (NCs) solar cells has been significantly promoted in recent years due to the optimization of device design by advanced interface engineering techniques. However, further development of CdTe NC solar cells is still limited by [...] Read more.

The power conversion efficiency (PCE) of solution-processed CdTe nanocrystals (NCs) solar cells has been significantly promoted in recent years due to the optimization of device design by advanced interface engineering techniques. However, further development of CdTe NC solar cells is still limited by the low open-circuit voltage (V_oc) (mostly in range of 0.5–0.7 V), which is mainly attributed to the charge recombination at the CdTe/electrode interface. Herein, we demonstrate a high-efficiency CdTe NCs solar cell by using organic polymer poly[bis(4–phenyl)(2,4,6–trimethylphenyl)amine] (PTAA) as the hole transport layer (HTL) to decrease the interface recombination and enhance the V_oc. The solar cell with the architecture of ITO/ZnO/CdS/CdSe/CdTe/PTAA/Au was fabricated via a layer-by-layer solution process. Experimental results show that PTAA offers better back contact for reducing interface resistance than the device without HTL. It is found that a dipole layer is produced between the CdTe NC thin film and the back contact electrode; thus the built–in electric field (V_bi) is reinforced, allowing more efficient carrier separation. By introducing the PTAA HTL in the device, the open–circuit voltage, short-circuit current density and the fill factor are simultaneously improved, leading to a high PCE of 6.95%, which is increased by 30% compared to that of the control device without HTL (5.3%). This work suggests that the widely used PTAA is preferred as the excellent HTL for achieving highly efficient CdTe NC solar cells. Full article

(This article belongs to the Special Issue Solar Thin Film Nanomaterials and Nanodevices)

► Show Figures

Figure 1

31 pages, 3476 KiB

Open AccessReview

Current Research on Zinc Oxide Nanoparticles: Synthesis, Characterization, and Biomedical Applications

by Ashok Kumar Mandal, Saurav Katuwal, Felix Tettey, Aakash Gupta, Salyan Bhattarai, Shankar Jaisi, Devi Prasad Bhandari, Ajay Kumar Shah, Narayan Bhattarai and Niranjan Parajuli

Nanomaterials 2022, 12(17), 3066; https://doi.org/10.3390/nano12173066 - 03 Sep 2022

Cited by 66 | Viewed by 8924

Abstract

Zinc oxide nanoparticles (ZnO-NPs) have piqued the curiosity of researchers all over the world due to their extensive biological activity. They are less toxic and biodegradable with the capacity to greatly boost pharmacophore bioactivity. ZnO-NPs are the most extensively used metal oxide nanoparticles [...] Read more.

Zinc oxide nanoparticles (ZnO-NPs) have piqued the curiosity of researchers all over the world due to their extensive biological activity. They are less toxic and biodegradable with the capacity to greatly boost pharmacophore bioactivity. ZnO-NPs are the most extensively used metal oxide nanoparticles in electronic and optoelectronics because of their distinctive optical and chemical properties which can be readily modified by altering the morphology and the wide bandgap. The biosynthesis of nanoparticles using extracts of therapeutic plants, fungi, bacteria, algae, etc., improves their stability and biocompatibility in many biological settings, and its biofabrication alters its physiochemical behavior, contributing to biological potency. As such, ZnO-NPs can be used as an effective nanocarrier for conventional drugs due to their cost-effectiveness and benefits of being biodegradable and biocompatible. This article covers a comprehensive review of different synthesis approaches of ZnO-NPs including physical, chemical, biochemical, and green synthesis techniques, and also emphasizes their biopotency through antibacterial, antifungal, anticancer, anti-inflammatory, antidiabetic, antioxidant, antiviral, wound healing, and cardioprotective activity. Green synthesis from plants, bacteria, and fungus is given special attention, with a particular emphasis on extraction techniques, precursors used for the synthesis and reaction conditions, characterization techniques, and surface morphology of the particles. Full article

► Show Figures

Graphical abstract

16 pages, 3534 KiB

Open AccessArticle

Carbon Dots Embedded Hybrid Microgel with Phenylboronic Acid as Monomer for Fluorescent Glucose Sensing and Glucose-Triggered Insulin Release at Physiological pH

by Jinhua Zhu, Wei Liu, Bowen Zhang, Danyang Zhou, Xiangze Fan, Xiaoge Wang and Xiuhua Liu

Nanomaterials 2022, 12(17), 3065; https://doi.org/10.3390/nano12173065 - 03 Sep 2022

Cited by 4 | Viewed by 2100

Abstract

A multifunctional and biocompatible hybrid microgel (poly(VPBA-AAm)-CD) using N, S-doped carbon dots (CDs) and ethylene glycol dimethacrylate (EGDMA) as cross-linking agents, and 4-vinylbenzene boronic acid (VPBA) and acrylamide (AAm) as monomers, was designed in this work. This microgel can be easily prepared by [...] Read more.

A multifunctional and biocompatible hybrid microgel (poly(VPBA-AAm)-CD) using N, S-doped carbon dots (CDs) and ethylene glycol dimethacrylate (EGDMA) as cross-linking agents, and 4-vinylbenzene boronic acid (VPBA) and acrylamide (AAm) as monomers, was designed in this work. This microgel can be easily prepared by a simple one-pot radical dispersion polymerization of the reactants using a rationally designed hydrogen-bonded complex method. The hybrid microgels were spherical particles with a smooth surface and an average particle size of 234 ± 8 nm. The poly(VPBA-AAm)-CD microgel displayed the glucose-responsive swelling within a clinically concerned range at a physiological pH and could realize the controllable release of insulin. In addition, the release rate of insulin in the hybrid microgel (poly(VPBA-AAm)-CD) could be triggered by glucose concentrations in the solution, and the increasing glucose concentrations can accelerate the insulin release. Further in vitro cytotoxicity studies showed that the microgel had good biocompatibility and no obvious toxicity to the cells. These indicate that the prepared microgel (poly(VPBA-AAm)-CD) may supply a new pattern for the self-regulating therapy of insulin deficiency in diabetes. Full article

(This article belongs to the Special Issue Advanced Studies in Colloidal Nano-Matters and Materials)

► Show Figures

Graphical abstract

11 pages, 1776 KiB

Open AccessArticle

Effect of Magnetic Heating on Stability of Magnetic Colloids

by Andrzej Drzewiński, Maciej Marć, Wiktor W. Wolak and Mirosław R. Dudek

Nanomaterials 2022, 12(17), 3064; https://doi.org/10.3390/nano12173064 - 03 Sep 2022

Viewed by 1172

Abstract

Stable aqueous suspension of magnetic nanoparticles is essential for effective magnetic hyperthermia and other applications of magnetic heating in an alternating magnetic field. However, the alternating magnetic field causes strong agglomeration of magnetic nanoparticles, and this can lead to undesirable phenomena that deteriorate [...] Read more.

Stable aqueous suspension of magnetic nanoparticles is essential for effective magnetic hyperthermia and other applications of magnetic heating in an alternating magnetic field. However, the alternating magnetic field causes strong agglomeration of magnetic nanoparticles, and this can lead to undesirable phenomena that deteriorate the bulk magnetic properties of the material. It has been shown how this magnetic field influences the distribution of magnetic agglomerates in the suspension. When investigating the influence of the sonication treatment on magnetic colloids, it turned out that the hydrodynamic diameter as a function of sonication time appeared to have a power-law character. The effect of magnetic colloid ageing on magnetic heating was discussed as well. It was shown how properly applied ultrasonic treatment could significantly improve the stability of the colloid of magnetic nanoparticles, ultimately leading to an increase in heating efficiency. The optimal sonication time for the preparation of the magnetic suspension turned out to be time-limited, and increasing it did not improve the stability of the colloid. The obtained results are important for the development of new materials where magnetic colloids are used and in biomedical applications. Full article

► Show Figures

Figure 1

13 pages, 3694 KiB

Open AccessEditor’s ChoiceArticle

Binary-Synaptic Plasticity in Ambipolar Ni-Silicide Schottky Barrier Poly-Si Thin Film Transistors Using Chitosan Electric Double Layer

by Ki-Woong Park and Won-Ju Cho

Nanomaterials 2022, 12(17), 3063; https://doi.org/10.3390/nano12173063 - 03 Sep 2022

Cited by 1 | Viewed by 1755

Abstract

We propose an ambipolar chitosan synaptic transistor that effectively responds to binary neuroplasticity. We fabricated the synaptic transistors by applying a chitosan electric double layer (EDL) to the gate insulator of the excimer laser annealed polycrystalline silicon (poly-Si) thin-film transistor (TFT) with Ni-silicide [...] Read more.

We propose an ambipolar chitosan synaptic transistor that effectively responds to binary neuroplasticity. We fabricated the synaptic transistors by applying a chitosan electric double layer (EDL) to the gate insulator of the excimer laser annealed polycrystalline silicon (poly-Si) thin-film transistor (TFT) with Ni-silicide (NiSi) Schottky-barrier source/drain (S/D) junction. The undoped poly-Si channel and the NiSi S/D contact allowed conduction by electrons and holes, resulting in artificial synaptic behavior in both p-type and n-type regions. A slow polarization reaction by the mobile ions such as anions (CH₃COO⁻ and OH⁻) and cations (H⁺) in the chitosan EDL induced hysteresis window in the transfer characteristics of the ambipolar TFTs. We demonstrated the excitatory post-synaptic current modulations and stable conductance modulation through repetitive potentiation and depression pulse. We expect the proposed ambipolar chitosan synaptic transistor that responds effectively to both positive and negative stimulation signals to provide more complex information process versatility for bio-inspired neuromorphic computing systems. Full article

(This article belongs to the Special Issue Intelligent Nanomaterials and Nanosystems)

► Show Figures

Figure 1

9 pages, 5000 KiB

Open AccessArticle

Preparing Colour-Tunable Tannic Acid-Based Carbon Dots by Changing the pH Value of the Reaction System

by Yan Li, Can Liu, Menglin Chen, Yunwu Zheng, Hao Tian, Rui Shi, Xiahong He and Xu Lin

Nanomaterials 2022, 12(17), 3062; https://doi.org/10.3390/nano12173062 - 03 Sep 2022

Cited by 4 | Viewed by 1634

Abstract

Biomass carbon dots (CDs) have the characteristics of being green, nontoxic, inexpensive, and simple to prepare, and they can be used in luminescence-related fields. In this study, red, green, and blue luminescent CDs were synthesised by a simple hydrothermal method under alkaline, neutral, [...] Read more.

Biomass carbon dots (CDs) have the characteristics of being green, nontoxic, inexpensive, and simple to prepare, and they can be used in luminescence-related fields. In this study, red, green, and blue luminescent CDs were synthesised by a simple hydrothermal method under alkaline, neutral, and acidic conditions using TA as carbon source and o-phthalaldehyde as blend. The unique optical properties of these CDs are due to the differences in their degrees of conjugation, which can be controlled by the pH value of the reaction system. These three kinds of biomass CDs have good applications in light-emitting diodes (LEDs). By mixing biomass CDs with epoxy resin, warm, and cold white LEDs with Commission Internationale de l’Elcairage (CIE) coordinates (0.35, 0.36) were successfully constructed on extremely stable multicolour CDs. This study shows that these biomass CDs are a promising material for white LED lighting. Full article

(This article belongs to the Special Issue Carbon-Based Quantum Dots)

► Show Figures

Figure 1

10 pages, 2113 KiB

Open AccessArticle

Physically Transient, Flexible, and Resistive Random Access Memory Based on Silver Ions and Egg Albumen Composites

by Lu Wang, Yukai Zhang, Peng Zhang and Dianzhong Wen

Nanomaterials 2022, 12(17), 3061; https://doi.org/10.3390/nano12173061 - 03 Sep 2022

Cited by 3 | Viewed by 1322

Abstract

Organic-resistance random access memory has high application potential in the field of next-generation green nonvolatile memory. Because of their biocompatibility and environmental friendliness, natural biomaterials are suitable for the fabrication of biodegradable and physically transient resistive switching memory devices. A flexible memory device [...] Read more.

Organic-resistance random access memory has high application potential in the field of next-generation green nonvolatile memory. Because of their biocompatibility and environmental friendliness, natural biomaterials are suitable for the fabrication of biodegradable and physically transient resistive switching memory devices. A flexible memory device with physically transient properties was fabricated with silver ions and egg albumen composites as active layers, which exhibited characteristics of write-once-read-many-times (WORM), and the incorporation of silver ions improved the ON/OFF current ratio of the device. The device can not only complete the logical operations of “AND gate” and “OR gate”, but its active layer film can also be dissolved in deionized water, indicating that it has the characteristics of physical transients. This biocompatible memory device is a strong candidate for a memory element for the construction of transient electronic systems. Full article

► Show Figures

Graphical abstract

15 pages, 3669 KiB

Open AccessArticle

In Situ Measurements of Strain Evolution in Graphene/Boron Nitride Heterostructures Using a Non-Destructive Raman Spectroscopy Approach

by Marc Mezzacappa, Dheyaa Alameri, Brian Thomas, Yoosuk Kim, Chi-Hou Lei and Irma Kuljanishvili

Nanomaterials 2022, 12(17), 3060; https://doi.org/10.3390/nano12173060 - 03 Sep 2022

Viewed by 1709

Abstract

The mechanical properties of engineered van der Waals (vdW) 2D materials and heterostructures are critically important for their implementation into practical applications. Using a non-destructive Raman spectroscopy approach, this study investigates the strain evolution of single-layer graphene (SLGr) and few-layered boron nitride/graphene (FLBN/SLGr) [...] Read more.

The mechanical properties of engineered van der Waals (vdW) 2D materials and heterostructures are critically important for their implementation into practical applications. Using a non-destructive Raman spectroscopy approach, this study investigates the strain evolution of single-layer graphene (SLGr) and few-layered boron nitride/graphene (FLBN/SLGr) heterostructures. The prepared 2D materials are synthesized via chemical vapor deposition (CVD) method and then transferred onto flexible polyethylene terephthalate (PET) substrates for subsequent strain measurements. For this study, a custom-built mechanical device-jig is designed and manufactured in-house to be used as an insert for the 3D piezoelectric stage of the Raman system. In situ investigation of the effects of applied strain in graphene detectable via Raman spectral data in characteristic bonds within SLGr and FLBN/SLGr heterostructures is carried out. The in situ strain evolution of the FLBN/SLGr heterostructures is obtained in the range of (0–0.5%) strain. It is found that, under the same strain, SLG exhibits a higher Raman shift in the 2D band as compared with FLBN/SLGr heterostructures. This research leads to a better understanding of strain dissipation in vertical 2D heterostacks, which could help improve the design and engineering of custom interfaces and, subsequently, control lattice structure and electronic properties. Moreover, this study can provide a new systematic approach for precise in situ strain assessment and measurements of other CVD-grown 2D materials and their heterostructures on a large scale for manufacturing a variety of future micro- and nano-scale devices on flexible substrates. Full article

(This article belongs to the Special Issue New Challenges in Designed Nanointerfaces)

► Show Figures

Figure 1

16 pages, 3720 KiB

Open AccessArticle

On the Reliability of HZO-Based Ferroelectric Capacitors: The Cases of Ru and TiN Electrodes

by Roman R. Khakimov, Anna G. Chernikova, Aleksandra A. Koroleva and Andrey M. Markeev

Nanomaterials 2022, 12(17), 3059; https://doi.org/10.3390/nano12173059 - 03 Sep 2022

Cited by 9 | Viewed by 3298

Abstract

Despite the great potential of Hf_0.5Zr_0.5O₂ (HZO) ferroelectrics, reliability issues, such as wake-up, fatigue, endurance limitations, imprint and retention loss, impede the implementation of HZO to nonvolatile memory devices. Herein, a study of the reliability properties in HZO-based [...] Read more.

Despite the great potential of Hf_0.5Zr_0.5O₂ (HZO) ferroelectrics, reliability issues, such as wake-up, fatigue, endurance limitations, imprint and retention loss, impede the implementation of HZO to nonvolatile memory devices. Herein, a study of the reliability properties in HZO-based stacks with the conventional TiN top electrode and Ru electrode, which is considered a promising alternative to TiN, is performed. An attempt to distinguish the mechanisms underlying the wake-up, fatigue and retention loss in both kinds of stacks is undertaken. Overall, both stacks show pronounced wake-up and retention loss. Moreover, the fatigue and retention loss were found to be worsened by Ru implementation. The huge fatigue was suggested to be because Ru does not protect HZO against oxygen vacancies generation during prolonged cycling. The vacancies generated in the presence of Ru are most likely deeper traps, as compared to the traps formed at the interface with the TiN electrode. Implementing the new procedure, which can separate the depolarization-caused retention loss from the imprint-caused one, reveal a rise in the depolarization contribution with Ru implementation, accompanied by the maintenance of similarly high imprint, as in the case with the TiN electrode. Results show that the mechanisms behind the reliability issues in HZO-based capacitors are very electrode dependent and simple approaches to replacing the TiN electrode with the one providing, for example, just higher remnant polarization or lower leakages, become irrelevant on closer examination. Full article

(This article belongs to the Special Issue Ferroelectric Nanostructures and Thin Films)

► Show Figures

Figure 1

25 pages, 4134 KiB

Open AccessArticle

Bacterial Surface Disturbances Affecting Cell Function during Exposure to Three-Compound Nanocomposites Based on Graphene Materials

by Agata Lange, Ewa Sawosz, Karolina Daniluk, Mateusz Wierzbicki, Artur Małolepszy, Marcin Gołębiewski and Sławomir Jaworski

Nanomaterials 2022, 12(17), 3058; https://doi.org/10.3390/nano12173058 - 02 Sep 2022

Cited by 2 | Viewed by 1427

Abstract

Combating pathogenic microorganisms in an era of ever-increasing drug resistance is crucial. The aim of the study was to evaluate the antibacterial mechanism of three-compound nanocomposites that were based on graphene materials. To determine the nanomaterials’ physicochemical properties, an analysis of the mean [...] Read more.

Combating pathogenic microorganisms in an era of ever-increasing drug resistance is crucial. The aim of the study was to evaluate the antibacterial mechanism of three-compound nanocomposites that were based on graphene materials. To determine the nanomaterials’ physicochemical properties, an analysis of the mean hydrodynamic diameter and zeta potential, transmission electron microscope (TEM) visualization and an FT-IR analysis were performed. The nanocomposites’ activity toward bacteria species was defined by viability, colony forming units, conductivity and surface charge, cell wall integrity, ATP concentration, and intracellular pH. To ensure the safe usage of nanocomposites, the presence of cytokines was also analyzed. Both the graphene and graphene oxide (GO) nanocomposites exhibited a high antibacterial effect toward all bacteria species (Enterobacter cloacae, Listeria monocytogenes, Salmonella enterica, and Staphylococcus aureus), as well as exceeded values obtained from exposure to single nanoparticles. Nanocomposites caused the biggest membrane damage, along with ATP depletion. Nanocomposites that were based on GO resulted in lower toxicity to the cell line. In view of the many aspects that must be considered when investigating such complex structures as are three-component nanocomposites, studies of their mechanism of action are crucial to their potential antibacterial use. Full article

► Show Figures

Figure 1

13 pages, 2678 KiB

Open AccessArticle

Evaluating the Growth of Ceria-Modified N-Doped Carbon-Based Materials and Their Performance in the Oxygen Reduction Reaction

by Xin Wen, Ying Chang and Jingchun Jia

Nanomaterials 2022, 12(17), 3057; https://doi.org/10.3390/nano12173057 - 02 Sep 2022

Cited by 3 | Viewed by 1255

Abstract

Owning to their distinctive electronic structure, rare-earth-based catalysts exhibit good performance in the oxygen reduction reaction (ORR) and can replace commercial Pt/C. In this study, CeO₂-modified N-doped C-based materials were synthesized using salt template and high-temperature calcination methods, and the synthesis [...] Read more.

Owning to their distinctive electronic structure, rare-earth-based catalysts exhibit good performance in the oxygen reduction reaction (ORR) and can replace commercial Pt/C. In this study, CeO₂-modified N-doped C-based materials were synthesized using salt template and high-temperature calcination methods, and the synthesis conditions were optimized. The successful synthesis of CeO₂–CN–800 was confirmed through a series of characterization methods and electrochemical tests. The test results show that the material has the peak onset potential of 0.90 V and the half-wave potential of 0.84 V, and has good durability and methanol resistance. The material demonstrates good ORR catalytic performance and can be used in Zn–air batteries. Moreover, it is an excellent catalyst for new energy equipment. Full article

(This article belongs to the Special Issue Nano-Materials in Electrocatalyst)

► Show Figures

Figure 1

16 pages, 6566 KiB

Open AccessArticle

Constructing a Double Alternant “Rigid-Flexible” Structure for Simultaneously Strengthening and Toughening the Interface of Carbon Fiber/Epoxy Composites

by Susu Zhang, Ping Han, Lina Yang, Shaokai Hu, Jianfa Wang and Zheng Gu

Nanomaterials 2022, 12(17), 3056; https://doi.org/10.3390/nano12173056 - 02 Sep 2022

Cited by 6 | Viewed by 1517

Abstract

An optimized “rigid-flexible” structure with multistage gradient modulus was constructed on carbon fiber (CF) surface via chemical grafting using “flexible” polyethyleneimine (PEI) and “rigid” polydopamine (PDA) between “rigid” CF and “flexible” epoxy (EP) to elaborate a double alternant “rigid-flexible” structure for simultaneously strengthening [...] Read more.

An optimized “rigid-flexible” structure with multistage gradient modulus was constructed on carbon fiber (CF) surface via chemical grafting using “flexible” polyethyleneimine (PEI) and “rigid” polydopamine (PDA) between “rigid” CF and “flexible” epoxy (EP) to elaborate a double alternant “rigid-flexible” structure for simultaneously strengthening and toughening CF/EP composites. PDA and PEI polymers can greatly enhance the roughness and wettability of CF surfaces, further strengthening the mechanical interlocking and chemical interactions between CFs and epoxy. Besides, the “rigid-flexible” structure endows the interface with a gradient transition modulus, which could uniformly transfer internal stress and effectively avoid the stress concentration. Moreover, the double alternant “rigid-flexible” could buffer the external loading, induce more micro cracks and propagation paths and, thereby, consume more energy during the destruction of the composite. The interfacial shear strength, interlaminar shear strength, impact strength increased by 80.2%, 23.5% and 167.2%, and the fracture toughness improved by 227.2%, compared with those of the unmodified CF composite, respectively. This creative strategy and design afford a promising guidance for the preparation and production of advanced CF/EP structural materials with high strength and toughness. Full article

► Show Figures

Graphical abstract

Journal Menu

Journal Browser

Nanomaterials, Volume 12, Issue 17 (September-1 2022) – 196 articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI