Nanomaterials

12 pages, 3341 KiB

Open AccessArticle

Reduced Graphene Oxide-Supported Iron-Cobalt Alloys as High-Performance Catalysts for Oxygen Reduction Reaction

by Jun Dong, Shanshan Wang, Peng Xi, Xinggao Zhang, Xinyu Zhu, Huining Wang and Taizhong Huang

Nanomaterials 2023, 13(19), 2735; https://doi.org/10.3390/nano13192735 - 9 Oct 2023

Cited by 3 | Viewed by 1642

Abstract

Exploring non-precious metal-based catalysts for oxygen reduction reactions (ORR) as a substitute for precious metal catalysts has attracted great attention in recent times. In this paper, we report a general methodology for preparing nitrogen-doped reduced graphene oxide (N–rGO)-supported, FeCo alloy (FeCo@N–rGO)-based catalysts for [...] Read more.

Exploring non-precious metal-based catalysts for oxygen reduction reactions (ORR) as a substitute for precious metal catalysts has attracted great attention in recent times. In this paper, we report a general methodology for preparing nitrogen-doped reduced graphene oxide (N–rGO)-supported, FeCo alloy (FeCo@N–rGO)-based catalysts for ORR. The structure of the FeCo@N–rGO based catalysts is investigated using X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and transition electron microscopy, etc. Results show that the FeCo alloy is supported by the rGO and carbon that derives from the organic ligand of Fe and Co ions. The eletrocatalytic performance is examined by cyclic voltammetry, linear scanning voltammetry, Tafel, electrochemical spectroscopy impedance, rotate disc electrode, and rotate ring disc electrode, etc. Results show that FeCo@N–rGO based catalysts exhibit an onset potential of 0.98 V (vs. RHE) and a half-wave potential of 0.93 V (vs. RHE). The excellent catalytic performance of FeCo@N–rGO is ascribed to its large surface area and the synergistic effect between FeCo alloy and N–rGO, which provides a large number of active sites and a sufficient surface area. Full article

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

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16 pages, 1358 KiB

Open AccessArticle

Possibility of Exciton Bose–Einstein Condensation in CdSe Nanoplatelets

by Davit A. Baghdasaryan, Volodya A. Harutyunyan, Eduard M. Kazaryan, Hayk A. Sarkisyan, Lyudvig S. Petrosyan and Tigran V. Shahbazyan

Nanomaterials 2023, 13(19), 2734; https://doi.org/10.3390/nano13192734 - 9 Oct 2023

Viewed by 1216

Abstract

The quasi-two-dimensional exciton subsystem in CdSe nanoplatelets is considered. It is theoretically shown that Bose–Einstein condensation (BEC) of excitons is possible at a nonzero temperature in the approximation of an ideal Bose gas and in the presence of an “energy gap” between the [...] Read more.

The quasi-two-dimensional exciton subsystem in CdSe nanoplatelets is considered. It is theoretically shown that Bose–Einstein condensation (BEC) of excitons is possible at a nonzero temperature in the approximation of an ideal Bose gas and in the presence of an “energy gap” between the ground and the first excited states of the two-dimensional exciton center of inertia of the translational motion. The condensation temperature (

T_{c}

) increases with the width of the “gap” between the ground and the first excited levels of size quantization. It is shown that when the screening effect of free electrons and holes on bound excitons is considered, the BEC temperature of the exciton subsystem increases as compared to the case where this effect is absent. The energy spectrum of the exciton condensate in a CdSe nanoplate is calculated within the framework of the weakly nonideal Bose gas approximation, considering the specifics of two-dimensional Born scattering. Full article

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13 pages, 15408 KiB

Open AccessArticle

Construction of Quasi-Ordered Metal-Organic Frameworks Superstructures via Colloidal Assembly of Anisotropic Particles for Selective Organic Vapor Sensing

by Yuheng He, Ling Bai, Baocang Liu, Hongwei Duan and Jun Zhang

Nanomaterials 2023, 13(19), 2733; https://doi.org/10.3390/nano13192733 - 9 Oct 2023

Cited by 1 | Viewed by 1455

Abstract

Colloidal assembly of anisotropic particles holds great promise for achieving diverse packing geometries and unique photonic properties. One intriguing candidate for anisotropic self-assembly is colloidal metal-organic frameworks (MOFs), which possess remarkable characteristics including substantial surface areas, tunable chemical properties, a wide range of [...] Read more.

Colloidal assembly of anisotropic particles holds great promise for achieving diverse packing geometries and unique photonic properties. One intriguing candidate for anisotropic self-assembly is colloidal metal-organic frameworks (MOFs), which possess remarkable characteristics including substantial surface areas, tunable chemical properties, a wide range of structural variations, and diverse polyhedral shapes. In this study, the colloidal assembly of nearly spherical and polyhedral MOFs particles to form quasi-ordered photonic superstructures was investigated. Specifically, monodisperse near-spherical ZIF-8 (NSZIF-8) and rhombic dodecahedron ZIF-8 (RDZIF-8) colloidal nanoparticles were synthesized as the fundamental building blocks. These nanoparticles are employed to construct MOFs-based self-assembled superstructures that exhibit thin-film interference optical properties. Importantly, these superstructures demonstrate exceptional responsiveness to gaseous homologues and isomers with approximate refractive indices. The dynamic reflection spectral patterns exhibited by these superstructures provide valuable insights into the diffusion rates and surface tension characteristics of the target solvents. These findings underscore the potential of MOFs-based superstructure thin films to discriminate between physiochemically similar solvents, opening new avenues for applications in various fields. Full article

(This article belongs to the Section Inorganic Materials and Metal-Organic Frameworks)

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14 pages, 15493 KiB

Open AccessArticle

Specific Recognition and Adsorption of Volatile Organic Compounds by Using MIL-125-Based Porous Fluorescence Probe Material

by Qiuyu Wu, Feiyang Tian, Wenqian Chen, Jianying Wang and Bo Lei

Nanomaterials 2023, 13(19), 2732; https://doi.org/10.3390/nano13192732 - 9 Oct 2023

Cited by 2 | Viewed by 1534

Abstract

The severity of the volatile organic compounds (VOCs) issue calls for effective detection and management of VOC materials. Metal-organic frameworks (MOFs) are organic-inorganic hybrid crystals with promising prospects in luminescent sensing for VOC detection and identification. However, MOFs have limitations, including weak response [...] Read more.

The severity of the volatile organic compounds (VOCs) issue calls for effective detection and management of VOC materials. Metal-organic frameworks (MOFs) are organic-inorganic hybrid crystals with promising prospects in luminescent sensing for VOC detection and identification. However, MOFs have limitations, including weak response signals and poor sensitivity towards VOCs, limiting their application to specific types of VOC gases. To address the issue of limited recognition and single luminosity for specific VOCs, we have introduced fluorescent guest molecules into MOFs as reference emission centers to enhance sensitivity. This composite material combines the gas adsorption ability of MOFs to effectively adsorb VOCs. We utilized (MIL-125/NH₂-MIL-125) as the parent material for adsorbing fluorescent molecules and selected suitable solid fluorescent probes (FGFL-B₁) through fluorescence enhancement using thioflavin T and MIL-125. FGFL-B₁ exhibited a heightened fluorescence response to various VOCs through charge transfer between fluorescent guest molecules and ligands. The fluorescence enhancement effect of FGFL-B₁ on tetrahydrofuran (THF) was particularly pronounced, accompanied by a color change from yellow to yellowish green in the presence of CCl₄. FGFL-B₁ demonstrated excellent adsorption properties for THF and CCl₄, with saturated adsorption capacities of 655.4 mg g⁻¹ and 811.2 mg g⁻¹, respectively. Furthermore, FGFL-B₁ displayed strong luminescence stability and reusability, making it an excellent sensing candidate. This study addresses the limitations of MOFs in VOC detection, opening avenues for industrial and environmental applications. Full article

(This article belongs to the Special Issue Metal Organic Framework (MOF)-Based Micro/Nanoscale Materials)

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14 pages, 4380 KiB

Open AccessArticle

Crystalline Mesoporous F-Doped Tin Dioxide Nanomaterial Successfully Prepared via a One Pot Synthesis at Room Temperature and Ambient Pressure

by Tariq Aqeel and Heather F. Greer

Nanomaterials 2023, 13(19), 2731; https://doi.org/10.3390/nano13192731 - 9 Oct 2023

Cited by 1 | Viewed by 1287

Abstract

We report the successful one pot synthesis of crystalline mesoporous tin dioxide powder doped with fluoride at ambient pressure and temperature. This material possesses a high surface area, narrow pore size distribution, small average crystallite sizes, and good opto-electrical properties. The existence of [...] Read more.

We report the successful one pot synthesis of crystalline mesoporous tin dioxide powder doped with fluoride at ambient pressure and temperature. This material possesses a high surface area, narrow pore size distribution, small average crystallite sizes, and good opto-electrical properties. The existence of fluorine increased the opto-electronic activity of tin dioxide by 20 times, and conductivity by 100 times compared with pristine tin dioxide prepared via the same method. The conductivity of SnO₂ in air at 25 °C is 5 × 10⁻⁵ S/m, whereas that of F–SnO₂ is 4.8 × 10⁻³ S/m. The structures of these materials were characterized with powder X-ray diffraction, N₂ sorption analysis, transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and UV-visible spectroscopy. Fluorine occupies the framework of tin dioxide by replacing some of the oxygen atoms. The structure, conductance, and optical properties of these materials are discussed in this paper. Full article

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

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13 pages, 15370 KiB

Open AccessArticle

Realizing the Ultralow Lattice Thermal Conductivity of Cu₃SbSe₄ Compound via Sulfur Alloying Effect

by Lijun Zhao, Haiwei Han, Zhengping Lu, Jian Yang, Xinmeng Wu, Bangzhi Ge, Lihua Yu, Zhongqi Shi, Abdulnasser M. Karami, Songtao Dong, Shahid Hussain, Guanjun Qiao and Junhua Xu

Nanomaterials 2023, 13(19), 2730; https://doi.org/10.3390/nano13192730 - 8 Oct 2023

Cited by 2 | Viewed by 1682

Abstract

Cu₃SbSe₄ is a potential p-type thermoelectric material, distinguished by its earth-abundant, inexpensive, innocuous, and environmentally friendly components. Nonetheless, the thermoelectric performance is poor and remains subpar. Herein, the electrical and thermal transport properties of Cu₃SbSe₄ were synergistically [...] Read more.

Cu₃SbSe₄ is a potential p-type thermoelectric material, distinguished by its earth-abundant, inexpensive, innocuous, and environmentally friendly components. Nonetheless, the thermoelectric performance is poor and remains subpar. Herein, the electrical and thermal transport properties of Cu₃SbSe₄ were synergistically optimized by S alloying. Firstly, S alloying widened the band gap, effectively alleviating the bipolar effect. Additionally, the substitution of S in the lattice significantly increased the carrier effective mass, leading to a large Seebeck coefficient of ~730 μVK⁻¹. Moreover, S alloying yielded point defect and Umklapp scattering to significantly depress the lattice thermal conductivity, and thus brought about an ultralow κ_lat ~0.50 Wm⁻¹K⁻¹ at 673 K in the solid solution. Consequently, multiple effects induced by S alloying enhanced the thermoelectric performance of the Cu₃SbSe₄-Cu₃SbS₄ solid solution, resulting in a maximum ZT value of ~0.72 at 673 K for the Cu₃SbSe_2.8S_1.2 sample, which was ~44% higher than that of pristine Cu₃SbSe₄. This work offers direction on improving the comprehensive TE in solid solutions via elemental alloying. Full article

(This article belongs to the Special Issue Advanced Nanoscale Materials for Thermoelectric Applications)

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12 pages, 6112 KiB

Open AccessArticle

Facile and Low-Cost Fabrication of SiO₂-Covered Au Nanoislands for Combined Plasmonic Enhanced Fluorescence Microscopy and SERS

by Alejandro Vidal, Sergio Molina-Prados, Ana Cros, Núria Garro, Manuel Pérez-Martínez, Raquel Álvaro, Gadea Mata, Diego Megías and Pablo A. Postigo

Nanomaterials 2023, 13(19), 2729; https://doi.org/10.3390/nano13192729 - 8 Oct 2023

Viewed by 1249

Abstract

An easy and low-cost way to fabricate monometallic Au nanoislands for plasmonic enhanced spectroscopy is presented. The method is based on direct thermal evaporation of Au on glass substrates to form nanoislands, with thicknesses between 2 and 15 nm, which are subsequently covered [...] Read more.

An easy and low-cost way to fabricate monometallic Au nanoislands for plasmonic enhanced spectroscopy is presented. The method is based on direct thermal evaporation of Au on glass substrates to form nanoislands, with thicknesses between 2 and 15 nm, which are subsequently covered by a thin layer of silicon dioxide. We have used HR-SEM and AFM to characterize the nanoislands, and their optical transmission reveals strong plasmon resonances in the visible. The plasmonic performance of the fabricated substrates has been tested in fluorescence and Raman scattering measurements of two probe materials. Enhancement factors up to 1.8 and 9×10⁴ are reported for confocal fluorescence and Raman microscopies, respectively, which are comparable to others obtained by more elaborated fabrication procedures. Full article

(This article belongs to the Special Issue Functional Nanomaterials for Sensing Devices: Synthesis, Characterization and Applications)

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15 pages, 18892 KiB

Open AccessArticle

Manufacturing Scalable Carbon Nanotube–Silicone/Kevlar Fabrics

by Prakash Giri, Vamsi Krishna Reddy Kondapalli, Kavitha Mulackampilly Joseph, Vesselin Shanov and Mark Schulz

Nanomaterials 2023, 13(19), 2728; https://doi.org/10.3390/nano13192728 - 8 Oct 2023

Cited by 1 | Viewed by 2439

Abstract

Carbon nanotube (CNT) hybrid composites were formed by combining a CNT and silicone elastomer solution with Kevlar yarn, Kevlar fabric, and Kevlar veil materials. The integration of a CNT-silicone matrix with Kevlar yarn and fabric materials produced a composite with moderate electrical and [...] Read more.

Carbon nanotube (CNT) hybrid composites were formed by combining a CNT and silicone elastomer solution with Kevlar yarn, Kevlar fabric, and Kevlar veil materials. The integration of a CNT-silicone matrix with Kevlar yarn and fabric materials produced a composite with moderate electrical and thermal conductivity due to CNT fabric combined with the strength of Kevlar fabric or yarn. In the material synthesis, a notable difficulty was that the CNT-silicone did not bond strongly to the Kevlar. The composites passed the Vertical Flame Test ASTM D6413 and the Forced Air Oven Test NFPA 1971. These hybrid composites can have multiple applications in areas requiring favorable conductivity, strength, and flame and heat resistance. The application areas include firefighter apparel, military equipment, conductive/smart structures, and flexible electronics. The synthesis process used to manufacture CNT-silicone/Kevlar composites yielded composite sheets with an area of 2250 cm². The process is scalable and customizable for the synthesis of CNT composites with tailored properties. Improvements in the bonding of CNT-silicone to Kevlar are being investigated. Full article

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14 pages, 33974 KiB

Open AccessEditor’s ChoiceArticle

Mitigating the Recrystallization of a Cold-Worked Cu-Al₂O₃ Nanocomposite via Enhanced Zener Drag by Nanocrstalline Cu-Oxide Particles

by Ramasis Goswami, Alex Moser and Chandra S. Pande

Nanomaterials 2023, 13(19), 2727; https://doi.org/10.3390/nano13192727 - 8 Oct 2023

Cited by 1 | Viewed by 1319

Abstract

The strength of metals and alloys at elevated temperatures typically decreases due to the recovery, recrystallization, grain growth, and growth of second-phase particles. We report here a cold-worked Cu-Al₂O₃ composite did not recrystallize up to a temperature of 0.83T_m [...] Read more.

The strength of metals and alloys at elevated temperatures typically decreases due to the recovery, recrystallization, grain growth, and growth of second-phase particles. We report here a cold-worked Cu-Al₂O₃ composite did not recrystallize up to a temperature of 0.83T_m of Cu. The composite was manufactured through the internal oxidation process of dilute Cu-0.15 wt.% Al alloy and was characterized by transmission electron microscopy to study the nature of oxide precipitates. As a result of internal oxidation, a small volume fraction (1%) of Al₂O₃ particles forms. In addition, a high density of extremely fine (2–5 nm) Cu₂O particles has been observed to form epitaxially within the elongated Cu grains. These finely dispersed second-phase Cu₂O particles enhance the Zener drag significantly by three orders of magnitude as compared to Al₂O₃ particles and retain their original size and spacing at elevated temperatures. This limits the grain boundary migration and the nucleation of defect-free regions of different orientations and inhibits the recrystallization process at elevated temperatures. In addition, due to the limited grain boundary migration, a bundle of stacking faults appears instead of annealing twins. This investigation has led to a better understanding of how to prevent the recrystallization process of heavily deformed metallic material containing oxide particles. Full article

(This article belongs to the Special Issue Design and Fabrication of Organic/Inorganic Nanocomposites, Volume II)

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11 pages, 2872 KiB

Open AccessArticle

Angle-Insensitive Ultrathin Broadband Visible Absorber Based on Dielectric–Semiconductor–Lossy Metal Film Stacks

by Yuanchen Ma, Junhao Hu, Wenfeng Li and Zhengmei Yang

Nanomaterials 2023, 13(19), 2726; https://doi.org/10.3390/nano13192726 - 8 Oct 2023

Cited by 2 | Viewed by 1321

Abstract

Ultrathin broadband absorbers with high efficiency, wide angular tolerance, and low fabrication cost are in demand for various applications. Here, we present an angle-insensitive ultrathin (<150 nm) broadband absorber with an average 96.88% (experiment) absorptivity in the whole visible range by utilizing a [...] Read more.

Ultrathin broadband absorbers with high efficiency, wide angular tolerance, and low fabrication cost are in demand for various applications. Here, we present an angle-insensitive ultrathin (<150 nm) broadband absorber with an average 96.88% (experiment) absorptivity in the whole visible range by utilizing a simple dielectric–semiconductor–lossy metal triple-layer film structure. The excellent broadband absorption performance of the device results from the combined action of the enhanced absorptions in the semiconductor and lossy metal layers exploiting strong interference effects and can be maintained over a wide viewing angle up to ±60°. Benefiting from the lossy metal providing additional absorption, our design reduces the requirement for the semiconductor’s material dispersion and has great flexibility in the material selection of the metal layer. Additionally, the lithography-free nature of the proposed broadband visible absorber provides a high-throughput fabrication convenience, thus holding great potential for its large-area applications in various fields. Full article

(This article belongs to the Special Issue Nano-Optics and Light-Matter Interactions)

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34 pages, 11250 KiB

Open AccessReview

Recent Advances of Composite Nanomaterials for Antibiofilm Application

by Ruilian Qi, Yuanyuan Cui, Jian Liu, Xiaoyu Wang and Huanxiang Yuan

Nanomaterials 2023, 13(19), 2725; https://doi.org/10.3390/nano13192725 - 8 Oct 2023

Cited by 9 | Viewed by 2142

Abstract

A biofilm is a microbial community formed by bacteria that adsorb on the surface of tissues or materials and is wrapped in extracellular polymeric substances (EPS) such as polysaccharides, proteins and nucleic acids. As a protective barrier, the EPS can not only prevent [...] Read more.

A biofilm is a microbial community formed by bacteria that adsorb on the surface of tissues or materials and is wrapped in extracellular polymeric substances (EPS) such as polysaccharides, proteins and nucleic acids. As a protective barrier, the EPS can not only prevent the penetration of antibiotics and other antibacterial agents into the biofilm, but also protect the bacteria in the biofilm from the attacks of the human immune system, making it difficult to eradicate biofilm-related infections and posing a serious threat to public health. Therefore, there is an urgent need to develop new and efficient antibiofilm drugs. Although natural enzymes (lysozyme, peroxidase, etc.) and antimicrobial peptides have excellent bactericidal activity, their low stability in the physiological environment and poor permeability in biofilms limit their application in antibiofilms. With the development of materials science, more and more nanomaterials are being designed to be utilized for antimicrobial and antibiofilm applications. Nanomaterials have great application prospects in antibiofilm because of their good biocompati-bility, unique physical and chemical properties, adjustable nanostructure, high permeability and non-proneness to induce bacterial resistance. In this review, with the application of composite nanomaterials in antibiofilms as the theme, we summarize the research progress of three types of composite nanomaterials, including organic composite materials, inorganic materials and organic–inorganic hybrid materials, used as antibiofilms with non-phototherapy and phototherapy modes of action. At the same time, the challenges and development directions of these composite nanomaterials in antibiofilm therapy are also discussed. It is expected we will provide new ideas for the design of safe and efficient antibiofilm materials. Full article

(This article belongs to the Special Issue Nanosomes in Precision Nanomedicine)

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13 pages, 3473 KiB

Open AccessArticle

Textile Waste-Derived Cobalt Nanoparticles Embedded in Active Carbon Fiber for Efficient Activation of Peroxymonosulfate to Remove Organic Pollutants

by Peiyuan Xiao, Ying Wang, Huanzheng Du, Zhiyong Yan, Bincheng Xu and Guangming Li

Nanomaterials 2023, 13(19), 2724; https://doi.org/10.3390/nano13192724 - 8 Oct 2023

Viewed by 1409

Abstract

Burning and dumping textile wastes have caused serious damage to the environment and are a huge waste of resources. In this work, cobalt nanoparticles embedded in active carbon fiber (Co/ACF) were prepared from bio-based fabric wastes, including cotton, flax and viscose. The obtained [...] Read more.

Burning and dumping textile wastes have caused serious damage to the environment and are a huge waste of resources. In this work, cobalt nanoparticles embedded in active carbon fiber (Co/ACF) were prepared from bio-based fabric wastes, including cotton, flax and viscose. The obtained Co/ACF was applied as a catalyst for the heterogeneous activation of peroxymonosulfate (PMS) to remove bisphenol A (BPA) from an aqueous solution. The results showed that cotton-, flax- and viscose-derived Co/ACF all exhibited excellent performance for BPA degradation; over ~97.0% of BPA was removed within 8 min. The Co/ACF/PMS system exhibited a wide operating pH range, with a low consumption of the catalyst (0.1 g L⁻¹) and PMS (0.14 g L⁻¹). The high specific surface area (342 m²/g) and mesoporous structure of Co/ACF allowed the efficient adsorption of pollutants as well as provided more accessible active sites for PMS activation. This study provided an example of using textile wastes to produce a valuable and recyclable catalyst for environmental remediation. Full article

(This article belongs to the Special Issue Nanocatalysts for Environmental Remediation)

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15 pages, 6121 KiB

Open AccessArticle

A Novel Strategy for the Synthesis of High Stability of Luminescent Zero Dimensional–Two Dimensional CsPbBr₃ Quantum Dot/1,4-bis(4-methylstyryl)benzene Nanoplate Heterostructures at an Atmospheric Condition

by Yanran Wang, Ming-yu Li, Shijie Liu, Yuan Ma, Bo Sun, Liangyu Wang, Haifei Lu, Xiaoyan Wen, Sisi Liu and Xumin Ding

Nanomaterials 2023, 13(19), 2723; https://doi.org/10.3390/nano13192723 - 7 Oct 2023

Cited by 1 | Viewed by 1691

Abstract

Perovskite quantum dots (QDs), emerging with excellent bright-green photoluminescence (PL) and a large absorption coefficient, are of great potential for the fabrication of light sources in underwater optical wireless communication systems. However, the instability caused by low formation energy and abundant surface traps [...] Read more.

Perovskite quantum dots (QDs), emerging with excellent bright-green photoluminescence (PL) and a large absorption coefficient, are of great potential for the fabrication of light sources in underwater optical wireless communication systems. However, the instability caused by low formation energy and abundant surface traps is still a major concern for perovskite-based light sources in underwater conditions. Herein, we propose ultra-stable zero dimensional–two dimensional (0D–2D) CsPbBr₃ QD/1,4-bis(4-methylstyryl)benzene (p-MSB) nanoplate (NP) heterostructures synthesized via a facile approach at room temperature in air. CsPbBr₃ QDs can naturally nucleate on the p-MSB NP toluene solution, and the radiative combination is drastically intensified owing to the electron transfer within the typical type-II heterostructures, leading to a sharply increased PLQY of the heterostructure thin films up to 200% compared with the pristine sample. The passivation of defects within CsPbBr₃ QDs can be effectively realized with the existence of p-MSB NPs, and thus the obviously improved PL is steadily witnessed in an ambient atmosphere and thermal environment. Meanwhile, the enhanced humidity stability and a peak EQE of 9.67% suggests a synergetic strategy for concurrently addressing the knotty problems on unsatisfied luminous efficiency and stability of perovskites for high-performance green-emitting optoelectronic devices in underwater applications. Full article

(This article belongs to the Special Issue Nano-Optics and Nano-Optoelectronics: Challenges and Future Trends)

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10 pages, 2732 KiB

Open AccessArticle

Exciton–Phonon Interactions in Strained Domes of Monolayer MoS₂ Studied by Resonance Raman Spectroscopy

by Jessica S. Lemos, Elena Blundo, Antonio Polimeni, Marcos A. Pimenta and Ariete Righi

Nanomaterials 2023, 13(19), 2722; https://doi.org/10.3390/nano13192722 - 7 Oct 2023

Cited by 3 | Viewed by 1516

Abstract

This work describes a resonance Raman study performed in the domes of monolayer MoS₂ using 23 different laser excitation energies covering the visible and near-infrared (NIR) ranges. The multiple excitation results allowed us to investigate the exciton–phonon interactions of different phonons (A [...] Read more.

This work describes a resonance Raman study performed in the domes of monolayer MoS₂ using 23 different laser excitation energies covering the visible and near-infrared (NIR) ranges. The multiple excitation results allowed us to investigate the exciton–phonon interactions of different phonons (A

^{'}

₁, E

^{'}

, and LA) with different excitonic optical transitions in biaxially strained monolayer MoS

_{2}

. The analysis of the intensities of the two first-order peaks, A

^{'}

₁ and E

^{'}

, and the double-resonance 2LA Raman band as a function of the laser excitation furnished the values of the energies of the indirect exciton and the direct excitonic transitions in the strained MoS

_{2}

domes. It was noticed that the out-of-plane A

^{'}

₁ phonon mode is significantly enhanced only by the indirect exciton I and the C exciton, whereas the in-plane E

^{'}

mode is only enhanced by the C exciton of the MoS₂ dome, thus revealing the weak interaction of these phonons with the A and B excitons in the strained MoS

_{2}

domes. On the other hand, the 2LA Raman band is significantly enhanced at the indirect exciton I and by the A (or B) exciton but not enhanced by the C exciton, thus showing that the LA edge phonons that participate in the double-resonance process in MoS

_{2}

have a weak interaction with the C exciton. Full article

(This article belongs to the Special Issue Excitons and Phonons in Two-Dimensional Materials: From Fundamental to Applications)

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8 pages, 1044 KiB

Open AccessArticle

Tuning Intrinsic Spin Hall Effect in Platinum/Ferrimagnetic Insulator Heterostructure in Moderately Dirty Regime

by Tianhui Li, Lin Liu, Zehan Chen, Wei Jia, Jianxin Ye, Xudong Cai, Doudou Huang, Wanshan Li, Fukang Chen, Xinjun Li, Jiahao Chen, Boxi Dong, Hang Xie, Anyuan Pan, Chao Zhi and Hongyu An

Nanomaterials 2023, 13(19), 2721; https://doi.org/10.3390/nano13192721 - 7 Oct 2023

Viewed by 1511

Abstract

Studying the mechanisms of the spin Hall effect (SHE) is essential for the fundamental understanding of spintronic physics. By now, despite the intensive studies of SHE on heavy metal (HM)/metallic magnet heterostructures, the SHE on HM/ferrimagnetic insulator (FMI) heterostructures still remains elusive. Here, [...] Read more.

Studying the mechanisms of the spin Hall effect (SHE) is essential for the fundamental understanding of spintronic physics. By now, despite the intensive studies of SHE on heavy metal (HM)/metallic magnet heterostructures, the SHE on HM/ferrimagnetic insulator (FMI) heterostructures still remains elusive. Here, we study the mechanism of SHE in the Pt/Tm

_{3}

Fe

_{5}

O

_{12}

(TmIG) heterostructure. We first tune the crystallinity and resistivity of Pt by an annealing method, and then study the spin–orbit torque (SOT) in the tuned-Pt/TmIG devices. The SOT generation efficiency per unit electric field and spin Hall angle were obtained, which are insensitive to the annealing temperature. We further demonstrate that the intrinsic contribution in the moderately dirty regime is responsible for the SHE in our Pt/TmIG bilayer. Our study provides an important piece of information for the SHE in FMI-based spintronic physics. Full article

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23 pages, 7412 KiB

Open AccessReview

Emerging Opportunities for 2D Materials in Neuromorphic Computing

by Chenyin Feng, Wenwei Wu, Huidi Liu, Junke Wang, Houzhao Wan, Guokun Ma and Hao Wang

Nanomaterials 2023, 13(19), 2720; https://doi.org/10.3390/nano13192720 - 7 Oct 2023

Cited by 4 | Viewed by 3671

Abstract

Recently, two-dimensional (2D) materials and their heterostructures have been recognized as the foundation for future brain-like neuromorphic computing devices. Two-dimensional materials possess unique characteristics such as near-atomic thickness, dangling-bond-free surfaces, and excellent mechanical properties. These features, which traditional electronic materials cannot achieve, hold [...] Read more.

Recently, two-dimensional (2D) materials and their heterostructures have been recognized as the foundation for future brain-like neuromorphic computing devices. Two-dimensional materials possess unique characteristics such as near-atomic thickness, dangling-bond-free surfaces, and excellent mechanical properties. These features, which traditional electronic materials cannot achieve, hold great promise for high-performance neuromorphic computing devices with the advantages of high energy efficiency and integration density. This article provides a comprehensive overview of various 2D materials, including graphene, transition metal dichalcogenides (TMDs), hexagonal boron nitride (h-BN), and black phosphorus (BP), for neuromorphic computing applications. The potential of these materials in neuromorphic computing is discussed from the perspectives of material properties, growth methods, and device operation principles. Full article

(This article belongs to the Special Issue Neuromorphic Devices: Materials, Structures and Bionic Applications)

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16 pages, 3806 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Shape-Driven Response of Gold Nanoparticles to X-rays

by Simona Tarantino, Caterina Capomolla, Alessandra Carlà, Livia Giotta, Mariafrancesca Cascione, Chiara Ingrosso, Edoardo Scarpa, Loris Rizzello, Anna Paola Caricato, Rosaria Rinaldi and Valeria De Matteis

Nanomaterials 2023, 13(19), 2719; https://doi.org/10.3390/nano13192719 - 7 Oct 2023

Cited by 2 | Viewed by 1630

Abstract

Radiotherapy (RT) involves delivering X-ray beams to the tumor site to trigger DNA damage. In this approach, it is fundamental to preserve healthy cells and to confine the X-ray beam only to the malignant cells. The integration of gold nanoparticles (AuNPs) in the [...] Read more.

Radiotherapy (RT) involves delivering X-ray beams to the tumor site to trigger DNA damage. In this approach, it is fundamental to preserve healthy cells and to confine the X-ray beam only to the malignant cells. The integration of gold nanoparticles (AuNPs) in the X-ray methodology could be considered a powerful tool to improve the efficacy of RT. Indeed, AuNPs have proven to be excellent allies in contrasting tumor pathology upon RT due to their high photoelectric absorption coefficient and unique physiochemical properties. However, an analysis of their physical and morphological reaction to X-ray exposure is necessary to fully understand the AuNPs’ behavior upon irradiation before treating the cells, since there are currently no studies on the evaluation of potential NP morphological changes upon specific irradiations. In this work, we synthesized two differently shaped AuNPs adopting two different techniques to achieve either spherical or star-shaped AuNPs. The spherical AuNPs were obtained with the Turkevich–Frens method, while the star-shaped AuNPs (AuNSs) involved a seed-mediated approach. We then characterized all AuNPs with Transmission Electron Microscopy (TEM), Uv-Vis spectroscopy, Dynamic Light Scattering (DLS), zeta potential and Fourier Transform Infrared (FTIR) spectroscopy. The next step involved the treatment of AuNPs with two different doses of X-radiation commonly used in RT, namely 1.8 Gy and 2 Gy, respectively. Following the X-rays’ exposure, the AuNPs were further characterized to investigate their possible physicochemical and morphological alterations induced with the X-rays. We found that AuNPs do not undergo any alteration, concluding that they can be safely used in RT treatments. Lastly, the actin rearrangements of THP-1 monocytes treated with AuNPs were also assessed in terms of coherency. This is a key proof to evaluate the possible activation of an immune response, which still represents a big limitation for the clinical translation of NPs. Full article

(This article belongs to the Special Issue Synthesis and Applications of Gold Nanoparticles: 2nd Edition)

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22 pages, 5738 KiB

Open AccessReview

Recent Advances in Functional Fiber-Based Wearable Triboelectric Nanogenerators

by Hakjeong Kim, Dinh Cong Nguyen, Thien Trung Luu, Zhengbing Ding, Zong-Hong Lin and Dukhyun Choi

Nanomaterials 2023, 13(19), 2718; https://doi.org/10.3390/nano13192718 - 6 Oct 2023

Cited by 7 | Viewed by 2359

Abstract

The quality of human life has improved thanks to the rapid development of wearable electronics. Previously, bulk structures were usually selected for the fabrication of high performance electronics, but these are not suitable for wearable electronics due to mobility limitations and comfortability. Fibrous [...] Read more.

The quality of human life has improved thanks to the rapid development of wearable electronics. Previously, bulk structures were usually selected for the fabrication of high performance electronics, but these are not suitable for wearable electronics due to mobility limitations and comfortability. Fibrous material-based triboelectric nanogenerators (TENGs) can provide power to wearable electronics due to their advantages such as light weight, flexibility, stretchability, wearability, etc. In this work, various fiber materials, multiple fabrication methods, and fundamentals of TENGs are described. Moreover, recent advances in functional fiber-based wearable TENGs are introduced. Furthermore, the challenges to functional fiber-based TENGs are discussed, and possible solutions are suggested. Finally, the use of TENGs in hybrid devices is introduced for a broader introduction of fiber-based energy harvesting technologies. Full article

(This article belongs to the Special Issue NANO KOREA 2023)

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17 pages, 18279 KiB

Open AccessArticle

Bioactive Glasses Containing Strontium or Magnesium Ions to Enhance the Biological Response in Bone Regeneration

by Sílvia Rodrigues Gavinho, Ana Sofia Pádua, Laura Isabel Vilas Holz, Isabel Sá-Nogueira, Jorge Carvalho Silva, João Paulo Borges, Manuel Almeida Valente and Manuel Pedro Fernandes Graça

Nanomaterials 2023, 13(19), 2717; https://doi.org/10.3390/nano13192717 - 6 Oct 2023

Cited by 15 | Viewed by 2013

Abstract

The non-surgical treatments are being required to reconstruct damaged tissue, prioritizing our body’s natural healing process. Thus, the use of bioactive materials such as bioactive glass has been studied to support the repair and restoration of hard and soft tissue. Thus, in this [...] Read more.

The non-surgical treatments are being required to reconstruct damaged tissue, prioritizing our body’s natural healing process. Thus, the use of bioactive materials such as bioactive glass has been studied to support the repair and restoration of hard and soft tissue. Thus, in this work Bioglass 45S5 was developed, adding 1 and 2%mol of SrO or MgO and the physical and biological properties were evaluated. The addition of MgO and SrO at the studied concentrations promoted the slight increase in non-bridging oxygens number, observed through the temperature shift in phase transitions to lower values compared to Bioglass 45S5. The insertion of the ions also showed a positive effect on Saos-2 cell viability, decreasing the cytotoxic of Bioglass 45S5. Besides the Ca/P ratio on the pellets surface demonstrating no evidence of higher reactivity between Bioglass 45S5 and Bioglass with Sr and Mg, micrographs show that at 24 h the Ca/P rich layer is denser than in Bioglass 45S5 after the contact with simulated body fluid. The samples with Sr and Mg show a higher antibacterial effect compared to Bioglass 45S5. The addition of the studied ions may benefit the biological response of Bioglass 45S5 in dental applications as scaffolds or coatings. Full article

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18 pages, 4082 KiB

Open AccessArticle

Controlled Crystal Growth of All-Inorganic CsPbI_2.2Br_0.8 Thin Film via Additive Strategy for Air-Processed Efficient Outdoor/Indoor Perovskite Solar Cells

by Jitendra Bahadur, Jun Ryu, SungWon Cho, Saemon Yoon, Dong-Gun Lee, Dong-Won Kang and Padmini Pandey

Nanomaterials 2023, 13(19), 2716; https://doi.org/10.3390/nano13192716 - 6 Oct 2023

Viewed by 1698

Abstract

The evolution of defects during perovskite film fabrication deteriorates the overall film quality and adversely affects the device efficiency of perovskite solar cells (PSCs). We endeavored to control the formation of defects by applying an additive engineering strategy using FABr, which retards the [...] Read more.

The evolution of defects during perovskite film fabrication deteriorates the overall film quality and adversely affects the device efficiency of perovskite solar cells (PSCs). We endeavored to control the formation of defects by applying an additive engineering strategy using FABr, which retards the crystal growth formation of CsPbI_2.2Br_0.8 perovskite by developing an intermediate phase at the initial stage. Improved crystalline and pinhole-free perovskite film with an optimal concentration of FABr-0.8M% additive was realized through crystallographic and microscopic analysis. Suppressed non-radiative recombination was observed through photoluminescence with an improved lifetime of 125 ns for FABr-0.8M% compared to the control film (83 ns). The champion device efficiency of 17.95% was attained for the FABr-0.8M% PSC, while 15.94% efficiency was achieved in the control PSC under air atmospheric conditions. Furthermore, an impressively high indoor performance of 31.22% was achieved for the FABr-0.8M% PSC under 3200 K (1000 lux) LED as compared to the control (23.15%). With a realistic approach of air processing and controlling the crystallization kinetics in wide-bandgap halide PSCs, this investigation paves the way for implementing additive engineering strategies to reduce defects in halide perovskites, which can further benefit efficiency enhancements in outdoor and indoor applications. Full article

(This article belongs to the Special Issue Advances in Novel Solar Energy Nanomaterials and Technical Applications)

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24 pages, 16525 KiB

Open AccessArticle

Hierarchical Structuring of Black Silicon Wafers by Ion-Flow-Stimulated Roughening Transition: Fundamentals and Applications for Photovoltaics

by Vyacheslav N. Gorshkov, Mykola O. Stretovych, Valerii F. Semeniuk, Mikhail P. Kruglenko, Nadiia I. Semeniuk, Victor I. Styopkin, Alexander M. Gabovich and Gernot K. Boiger

Nanomaterials 2023, 13(19), 2715; https://doi.org/10.3390/nano13192715 - 6 Oct 2023

Viewed by 1454

Abstract

Ion-flow-stimulated roughening transition is a phenomenon that may prove useful in the hierarchical structuring of nanostructures. In this work, we have investigated theoretically and experimentally the surface texturing of single-crystal and multi-crystalline silicon wafers irradiated using ion-beam flows. In contrast to previous studies, [...] Read more.

Ion-flow-stimulated roughening transition is a phenomenon that may prove useful in the hierarchical structuring of nanostructures. In this work, we have investigated theoretically and experimentally the surface texturing of single-crystal and multi-crystalline silicon wafers irradiated using ion-beam flows. In contrast to previous studies, ions had relatively low energies, whereas flow densities were high enough to induce a quasi-liquid state in the upper silicon layers. The resulting surface modifications reduced the wafer light reflectance to values characteristic of black silicon, widely used in solar energetics. Features of nanostructures on different faces of silicon single crystals were studied numerically based on the mesoscopic Monte Carlo model. We established that the formation of nano-pyramids, ridges, and twisting dune-like structures is due to the stimulated roughening transition effect. The aforementioned variety of modified surface morphologies arises due to the fact that the effects of stimulated surface diffusion of atoms and re-deposition of free atoms on the wafer surface from the near-surface region are manifested to different degrees on different Si faces. It is these two factors that determine the selection of the allowable “trajectories” (evolution paths) of the thermodynamic system along which its Helmholtz free energy, F, decreases, concomitant with an increase in the surface area of the wafer and the corresponding changes in its internal energy,

U

(

d U > 0

), and entropy,

S

(

d S > 0

), so that

d F = d U - T d S < 0

, where

T

is the absolute temperature. The basic theoretical concepts developed were confirmed in experimental studies, the results of which showed that our method could produce, abundantly, black silicon wafers in an environmentally friendly manner compared to traditional chemical etching. Full article

(This article belongs to the Special Issue Advanced Nanomaterials and Nanotechnology for Solar Cells)

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15 pages, 10546 KiB

Open AccessArticle

Caloric Effect Due to the Aharonov–Bohm Flux in an Antidot

by Patricia Martínez-Rojas, M. Esperanza Benavides-Vergara, Francisco J. Peña and Patricio Vargas

Nanomaterials 2023, 13(19), 2714; https://doi.org/10.3390/nano13192714 - 6 Oct 2023

Viewed by 1151

Abstract

In this work, we report the caloric effect for an electronic system of the antidot type, modeled by combining a repulsive and attractive potential (parabolic confinement). In this system, we consider the action of a perpendicular external magnetic field and the possibility of [...] Read more.

In this work, we report the caloric effect for an electronic system of the antidot type, modeled by combining a repulsive and attractive potential (parabolic confinement). In this system, we consider the action of a perpendicular external magnetic field and the possibility of having an Aharonov–Bohm flux (AB-flux) generated by a current passing through a solenoid placed inside the forbidden zone for the electron. The energy levels are obtained analytically, and the model is known as the Bogachek and Landman model. We propose to control the caloric response of the system by varying only the AB-flux, finding that, in the absence of an external magnetic field, the maximization of the effect always occurs at the same AB-flux intensity, independently of the temperature, while fixing the external magnetic field at a non-zero value breaks this symmetry and changes the point where the caloric phenomenon is maximized and is different depending on the temperature to which the process is carried. Our calculations indicate that using an effective electron mass of GaAs heterostructures and a trap intensity of the order of 2.896 meV, the modification of the AB-flux achieves a variation in temperature of the order of 1 K. Our analysis suggests that increasing the parabolic confinement twofold increases the effect threefold, while increasing the antidot size generates the reverse effect, i.e., a strong decrease in the caloric phenomenon under study. Due to the great diversity in technological applications that have antidots in electronics, the possibility of controlling their thermal response simply by varying the intensity of the internal current inside the solenoid (i.e., the intensity of AB-flux) can be a platform of interest for experimental studies. Full article

(This article belongs to the Special Issue Quantum Materials with Low-Dimensional Nanostructures: From Fundamentals to Applications)

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14 pages, 4373 KiB

Open AccessCommunication

Stearic Acid as an Atomic Layer Deposition Inhibitor: Spectroscopic Insights from AFM-IR

by Saumya Satyarthy, Md Hasan Ul Iqbal, Fairoz Abida, Ridwan Nahar, Adam J. Hauser, Mark Ming-Cheng Cheng and Ayanjeet Ghosh

Nanomaterials 2023, 13(19), 2713; https://doi.org/10.3390/nano13192713 - 6 Oct 2023

Cited by 1 | Viewed by 1910

Abstract

Modern-day chip manufacturing requires precision in placing chip materials on complex and patterned structures. Area-selective atomic layer deposition (AS-ALD) is a self-aligned manufacturing technique with high precision and control, which offers cost effectiveness compared to the traditional patterning techniques. Self-assembled monolayers (SAMs) have [...] Read more.

Modern-day chip manufacturing requires precision in placing chip materials on complex and patterned structures. Area-selective atomic layer deposition (AS-ALD) is a self-aligned manufacturing technique with high precision and control, which offers cost effectiveness compared to the traditional patterning techniques. Self-assembled monolayers (SAMs) have been explored as an avenue for realizing AS-ALD, wherein surface-active sites are modified in a specific pattern via SAMs that are inert to metal deposition, enabling ALD nucleation on the substrate selectively. However, key limitations have limited the potential of AS-ALD as a patterning method. The choice of molecules for ALD blocking SAMs is sparse; furthermore, deficiency in the proper understanding of the SAM chemistry and its changes upon metal layer deposition further adds to the challenges. In this work, we have addressed the above challenges by using nanoscale infrared spectroscopy to investigate the potential of stearic acid (SA) as an ALD inhibiting SAM. We show that SA monolayers on Co and Cu substrates can inhibit ZnO ALD growth on par with other commonly used SAMs, which demonstrates its viability towards AS-ALD. We complement these measurements with AFM-IR, which is a surface-sensitive spatially resolved technique, to obtain spectral insights into the ALD-treated SAMs. The significant insight obtained from AFM-IR is that SA SAMs do not desorb or degrade with ALD, but rather undergo a change in substrate coordination modes, which can affect ALD growth on substrates. Full article

(This article belongs to the Special Issue ALD Technique for Functional Coatings of Nanostructured Materials)

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14 pages, 6500 KiB

Open AccessArticle

Temperature-Dependent Structural and Electrical Properties of Metal-Organic CVD MoS₂ Films

by Roman I. Romanov, Ivan V. Zabrosaev, Anastasia A. Chouprik, Dmitry I. Yakubovsky, Mikhail K. Tatmyshevskiy, Valentyn S. Volkov and Andrey M. Markeev

Nanomaterials 2023, 13(19), 2712; https://doi.org/10.3390/nano13192712 - 6 Oct 2023

Cited by 4 | Viewed by 1735

Abstract

Metal-Organic CVD method (MOCVD) allows for deposition of ultrathin 2D transition metal dichalcogenides (TMD) films of electronic quality onto wafer-scale substrates. In this work, the effect of temperature on structure, chemical states, and electronic qualities of the MOCVD MoS₂ films were investigated. [...] Read more.

Metal-Organic CVD method (MOCVD) allows for deposition of ultrathin 2D transition metal dichalcogenides (TMD) films of electronic quality onto wafer-scale substrates. In this work, the effect of temperature on structure, chemical states, and electronic qualities of the MOCVD MoS₂ films were investigated. The results demonstrate that the temperature increase in the range of 650 °C to 950 °C results in non-monotonic average crystallite size variation. Atomic force microscopy (AFM), transmission electron microscopy (TEM), and Raman spectroscopy investigation has established the film crystal structure improvement with temperature increase in this range. At the same time, X-Ray photoelectron spectroscopy (XPS) method allowed to reveal non-stoichiometric phase fraction increase, corresponding to increased sulfur vacancies (V_S) concentration from approximately 0.9 at.% to 3.6 at.%. Established dependency between the crystallite domains size and V_S concentration suggests that these vacancies are form predominantly at the grain boundaries. The results suggest that an increased Vs concentration and enhanced charge carriers scattering at the grains’ boundaries should be the primary reasons of films’ resistivity increase from 4 kΩ·cm to 39 kΩ·cm. Full article

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24 pages, 6284 KiB

Open AccessEditor’s ChoiceReview

Progress of Polymer-Based Dielectric Composites Prepared Using Fused Deposition Modeling 3D Printing

by Xueling Hu, Alix Marcelle Sansi Seukep, Velmurugan Senthooran, Lixin Wu, Lei Wang, Chen Zhang and Jianlei Wang

Nanomaterials 2023, 13(19), 2711; https://doi.org/10.3390/nano13192711 - 6 Oct 2023

Viewed by 1974

Abstract

Polymer-based dielectric composites are of great importance in advanced electronic industries and energy storage because of their high dielectric constant, good processability, low weight, and low dielectric loss. FDM (Fused Deposition Modeling) is a greatly accessible additive manufacturing technology, which has a number [...] Read more.

Polymer-based dielectric composites are of great importance in advanced electronic industries and energy storage because of their high dielectric constant, good processability, low weight, and low dielectric loss. FDM (Fused Deposition Modeling) is a greatly accessible additive manufacturing technology, which has a number of applications in the fabrication of RF components, but the unavoidable porosity in FDM 3D-printed materials, which affects the dielectric properties of the materials, and the difficulty of large-scale fabrication of composites by FDM limit its application scope. This study’s main focus is on how the matrix, filler, interface, and FDM 3D printing parameters influence the electrical properties of FDM-printed polymer-based dielectric composites. This review article starts with the fundamental theory of dielectrics. It is followed by a summary of the factors influencing dielectric properties in recent research developments, as well as a projection for the future development of FDM-prepared polymer-based dielectric composites. Finally, improving the comprehensive performance of dielectric composites is an important direction for future development. Full article

(This article belongs to the Special Issue Additive Manufacturing of Hybrid and Nanomaterials)

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14 pages, 3390 KiB

Open AccessArticle

Multifunctional Biotemplated Micromotors for In Situ Decontamination of Antibiotics and Heavy Metals in Soil and Groundwater

by Haohao Cui, Ke Wang, Enhui Ma and Hong Wang

Nanomaterials 2023, 13(19), 2710; https://doi.org/10.3390/nano13192710 - 6 Oct 2023

Cited by 3 | Viewed by 1898

Abstract

The ubiquitous pollution by antibiotics and heavy metal ions has posed great threats to human health and the ecological environment. Therefore, we developed a self-propelled tubular micromotor based on natural fibers as an active heterogeneous catalyst for antibiotic degradation and adsorbent for heavy [...] Read more.

The ubiquitous pollution by antibiotics and heavy metal ions has posed great threats to human health and the ecological environment. Therefore, we developed a self-propelled tubular micromotor based on natural fibers as an active heterogeneous catalyst for antibiotic degradation and adsorbent for heavy metal ions in soil/water. The prepared micromotors can move in the presence of hydrogen peroxide (H₂O₂) through a bubble recoil mechanism. The MnO₂ NPs and MnFe₂O₄ NPs loaded on the hollow fibers not only enabled self-driven motion and magnetic control but also served as activators of peroxymononsulfate (PMS) and H₂O₂ to produce active free radicals SO₄^•− and •OH. Benefiting from the self-propulsion and bubble generation, the micromotors can effectively overcome the disadvantage of low diffusivity of traditional heterogeneous catalysts, achieving the degradation of more than 90% TC in soil within 30 min. Meanwhile, due to the large specific surface area, abundant active sites, and strong negative zeta potential, the micromotors can effectively adsorb heavy metal ions in the water environment. In 120 min, self-propelled micromotors removed more than 94% of lead ions, an increase of 47% compared to static micromotors, illustrating the advantages of on-the-fly capture. The prepared micromotors with excellent catalytic performance and adsorption capacity can simultaneously degrade antibiotics and adsorb heavy metal ions. Moreover, the magnetic response enabled the micromotors to be effectively separated from the system after completion of the task, avoiding the problem of secondary pollution. Overall, the proposed micromotors provide a new approach to the utilization of natural materials in environmental applications. Full article

(This article belongs to the Special Issue Advances in Micro-/Nanorobotics)

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15 pages, 5020 KiB

Open AccessArticle

Alginate Microsponges as a Scaffold for Delivery of a Therapeutic Peptide against Rheumatoid Arthritis

by Daniela Ariaudo, Francesca Cavalieri, Antonio Rinaldi, Ana Aguilera, Matilde Lopez, Hilda Garay Perez, Ariel Felipe, Maria del Carmen Dominguez, Odalys Ruiz, Gillian Martinez and Mariano Venanzi

Nanomaterials 2023, 13(19), 2709; https://doi.org/10.3390/nano13192709 - 5 Oct 2023

Cited by 5 | Viewed by 1715

Abstract

The quest for biocompatible drug-delivery devices that could be able to open new administration routes is at the frontier of biomedical research. In this contribution, porous polysaccharide-based microsponges based on crosslinked alginate polymers were developed and characterized by optical spectroscopy and nanoscopic microscopy [...] Read more.

The quest for biocompatible drug-delivery devices that could be able to open new administration routes is at the frontier of biomedical research. In this contribution, porous polysaccharide-based microsponges based on crosslinked alginate polymers were developed and characterized by optical spectroscopy and nanoscopic microscopy techniques. We show that macropores with a size distribution ranging from 50 to 120 nm enabled efficient loading and delivery of a therapeutic peptide (CIGB814), presently under a phase 3 clinical trial for the treatment of rheumatoid arthritis. Alginate microsponges showed 80% loading capacity and sustained peptide release over a few hours through a diffusional mechanism favored by partial erosion of the polymer scaffold. The edible and biocompatible nature of alginate polymers open promising perspectives for developing a new generation of polysaccharide-based carriers for the controlled delivery of peptide drugs, exploiting alternative routes with respect to intravenous administration. Full article

(This article belongs to the Special Issue Advanced Nanomaterials in Biomedical Application (2nd Edition))

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17 pages, 4882 KiB

Open AccessFeature PaperArticle

Insights into the Sensing Mechanism of a Metal-Oxide Solid Solution via Operando Diffuse Reflectance Infrared Fourier Transform Spectroscopy

by Elena Spagnoli, Matteo Valt, Andrea Gaiardo, Barbara Fabbri and Vincenzo Guidi

Nanomaterials 2023, 13(19), 2708; https://doi.org/10.3390/nano13192708 - 5 Oct 2023

Cited by 3 | Viewed by 1368

Abstract

Recently, the influence of Nb addition in the oxide solid solution of Sn and Ti was investigated with regard to the morphological, structural and electrical properties for the production of chemoresistive gas sensors. (Sn,Ti,Nb)_xO₂-based sensors showed promising features for [...] Read more.

Recently, the influence of Nb addition in the oxide solid solution of Sn and Ti was investigated with regard to the morphological, structural and electrical properties for the production of chemoresistive gas sensors. (Sn,Ti,Nb)_xO₂-based sensors showed promising features for ethanol monitoring in commercial or industrial settings characterized by frequent variation in relative humidity. Indeed, the three-metal solid solution highlighted a higher response level vs. ethanol than the most widely used SnO₂ and a remarkably low effect of relative humidity on the film resistance. Nevertheless, lack of knowledge still persists on the mechanisms of gas reaction occurring at the surface of these nanostructures. In this work, operando Diffuse Reflectance Infrared Fourier Transform spectroscopy was used on SnO₂- and on (Sn,Ti,Nb)_xO₂-based sensors to combine the investigations on the transduction function, i.e., the read-out of the device activity, with the investigations on the receptor function, i.e., compositional characterization of the active sensing element in real time and under operating conditions. The sensors performance was explained by probing the interaction of H₂O and ethanol molecules with the material surface sites. This information is fundamental for fine-tuning of material characteristics for any specific gas sensing applications. Full article

(This article belongs to the Special Issue Surface Functionalization of Carbon-Based and Metal Oxide Nanostructures for Gas Sensing)

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10 pages, 2340 KiB

Open AccessFeature PaperArticle

Controlling the Morphology of Tellurene for a High-Performance H₂S Chemiresistive Room-Temperature Gas Sensor

by Yeonjin Je and Sang-Soo Chee

Nanomaterials 2023, 13(19), 2707; https://doi.org/10.3390/nano13192707 - 5 Oct 2023

Viewed by 1407

Abstract

A two-dimensional (2D) van der Waals material composed only of tellurium (Te) atoms—tellurene—is drawing attention because of its high intrinsic electrical conductivity and strong interaction with gas molecules, which could allow the development of high-performance chemiresistive sensors. However, the correlation between the morphologies [...] Read more.

A two-dimensional (2D) van der Waals material composed only of tellurium (Te) atoms—tellurene—is drawing attention because of its high intrinsic electrical conductivity and strong interaction with gas molecules, which could allow the development of high-performance chemiresistive sensors. However, the correlation between the morphologies and gas detection properties of tellurene has not yet been studied in depth, and few reports exist on tellurene-based hydrogen sulfide (H₂S) chemiresistive sensors in spite of their strong interaction with H₂S molecules. Here, we investigate the morphology-dependent H₂S gas detection properties of tellurene synthesized using a hydrothermal method. To tailor the morphologies of tellurene, the molecular weight of the surfactant was controlled, revealing that a 1D or 2D form was synthesized and also accompanied with the high crystallinity. The 1D tellurene-based chemiresistive sensor presented superior H₂S detection properties compared to the 2D form, achieving a gas response (R_g/R_a) of ~38, even at room temperature. This outstanding performance was attributed to the high intrinsic electrical conductivity and high specific surface area of the resultant 1D tellurene. Full article

(This article belongs to the Special Issue Low-Dimensional Nanostructures: Synthesis, Characterization and Applications)

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13 pages, 3602 KiB

Open AccessArticle

The Real-Time Monitoring of the Laser-Induced Functionalization of Transparent Conductive Oxide Films

by Takuya Hosokai and Junichi Nomoto

Nanomaterials 2023, 13(19), 2706; https://doi.org/10.3390/nano13192706 - 5 Oct 2023

Viewed by 1301

Abstract

Laser-induced functionalization using excimer laser irradiation has been widely applied to transparent conductive oxide films. However, exploring suitable irradiation conditions is time-consuming and cost-ineffective as there are numerous routine film fabrication and analytical processes. Thus, we herein explored a real-time monitoring technique of [...] Read more.

Laser-induced functionalization using excimer laser irradiation has been widely applied to transparent conductive oxide films. However, exploring suitable irradiation conditions is time-consuming and cost-ineffective as there are numerous routine film fabrication and analytical processes. Thus, we herein explored a real-time monitoring technique of the laser-induced functionalization of transparent conductive oxide films. We developed two types of monitoring apparatus, electrical and optical, and applied them to magnetron-sputtered, Sn-doped In₂O₃ films grown on glass substrates and hydrogen-doped In₂O₃ films on glass or plastic substrates using a picosecond Nd:YAG pulsed laser. Both techniques could monitor the functionalization from a change in the properties of the films on glass substrates via laser irradiation, but electrical measurement was unsuitable for the plastic samples because of a laser-induced degradation of the underlying plastic substrate, which harmed proper electrical contact. Instead, we proposed that the optical properties in the near-infrared region are more suitable for monitoring. The changes in the optical properties were successfully detected visually in real-time by using an InGaAs near-infrared camera. Full article

(This article belongs to the Special Issue Advanced Characterization Techniques for Nanomaterials)

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