Nanomaterials

17 pages, 4357 KiB

Open AccessArticle

Design and Synthesis of Functional Silane-Based Silicone Resin and Application in Low-Temperature Curing Silver Conductive Inks

by Zhiqiang Tang, Yanxia Liu, Yagang Zhang, Zicai Sun, Weidong Huang, Zhikai Chen, Xiaoli Jiang and Lin Zhao

Nanomaterials 2023, 13(6), 1137; https://doi.org/10.3390/nano13061137 - 22 Mar 2023

Cited by 2 | Viewed by 1727

Abstract

In the field of flexible electronics manufacturing, inkjet printing technology is a research hotspot, and it is key to developing low-temperature curing conductive inks that meet printing requirements and have suitable functions. Herein, methylphenylamino silicon oil (N75) and epoxy-modified silicon oil (SE35) were [...] Read more.

In the field of flexible electronics manufacturing, inkjet printing technology is a research hotspot, and it is key to developing low-temperature curing conductive inks that meet printing requirements and have suitable functions. Herein, methylphenylamino silicon oil (N75) and epoxy-modified silicon oil (SE35) were successfully synthesized through functional silicon monomers, and they were used to prepare silicone resin 1030H with nano SiO₂. 1030H silicone resin was used as the resin binder for silver conductive ink. The silver conductive ink we prepared with 1030H has good dispersion performance with a particle size of 50–100 nm, as well as good storage stability and excellent adhesion. Additionally, the printing performance and conductivity of the silver conductive ink prepared with n,n-dimethylformamide (DMF): proprylene glycol monomethyl ether (PM) (1:1) as solvent are better than those of the silver conductive ink prepared by DMF and PM solvent. Cured at a low temperature of 160 °C, the resistivity of 1030H-Ag-82%-3 conductive ink is 6.87 × 10⁻⁶ Ω·m, and that of 1030H-Ag-92%-3 conductive ink is 0.564 × 10⁻⁶ Ω·m, so the low-temperature curing silver conductive ink has high conductivity. The low-temperature curing silver conductive ink we prepared meets the printing requirements and has potential for practical applications. Full article

(This article belongs to the Special Issue Nanomaterials for Electron Devices)

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15 pages, 5725 KiB

Open AccessArticle

The Efficiency Study of Graphene Synthesis on Copper Substrate via Chemical Vapor Deposition Method with Methanol Precursor

by Bohr-Ran Huang, Shang-Chao Hung, Yung-Shou Ho, Yi-Siou Chen and Wein-Duo Yang

Nanomaterials 2023, 13(6), 1136; https://doi.org/10.3390/nano13061136 - 22 Mar 2023

Cited by 2 | Viewed by 1444

Abstract

Few-layer graphene was successfully synthesized on copper foil via chemical vapor deposition with methanol as a carbon source. This was confirmed by optical microscopy observation, Raman spectra measurement, I_2D/I_G ratio calculation, and 2D-FWHM value comparisons. Monolayer graphene was also found [...] Read more.

Few-layer graphene was successfully synthesized on copper foil via chemical vapor deposition with methanol as a carbon source. This was confirmed by optical microscopy observation, Raman spectra measurement, I_2D/I_G ratio calculation, and 2D-FWHM value comparisons. Monolayer graphene was also found in similar standard procedures, but it required higher growth temperature and longer time periods. The cost-efficient growth conditions for few-layer graphene are thoroughly discussed via TEM observation and AFM measurement. In addition, it has been confirmed that the growth period can be shortened by increasing growth temperature. With the H₂ gas flow rate fixed at 15 sccm, few-layer graphene was synthesized at the lower growth temperature of 700 °C in 30 min, and at 900 °C growth temperature in only 5 min. Successful growth was also achieved without adding hydrogen gas flow; this is probably because H₂ can be induced from the decomposition of methanol. Through further defects study of few-layer graphene via TEM observation and AFM measurement, we tried to find possible ways for efficiency and quality management in graphene synthesis in industrial applications. Lastly, we investigated graphene formation after pre-treatment with different gas compositions, and found that gas selection is a crucial factor for a successful synthesis. Full article

(This article belongs to the Section 2D and Carbon Nanomaterials)

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12 pages, 2803 KiB

Open AccessArticle

Thermally Deposited Sb₂Se₃/CdS-Based Solar Cell: Experimental and Theoretical Analysis

by Mamta, Raman Kumari, Chandan Yadav, Rahul Kumar, Kamlesh Kumar Maurya and Vidya Nand Singh

Nanomaterials 2023, 13(6), 1135; https://doi.org/10.3390/nano13061135 - 22 Mar 2023

Cited by 3 | Viewed by 1692

Abstract

As a promising solar absorber material, antimony selenide (Sb₂Se₃) has gained popularity. However, a lack of knowledge regarding material and device physics has slowed the rapid growth of Sb₂Se₃-based devices. This study compares the experimental [...] Read more.

As a promising solar absorber material, antimony selenide (Sb₂Se₃) has gained popularity. However, a lack of knowledge regarding material and device physics has slowed the rapid growth of Sb₂Se₃-based devices. This study compares the experimental and computational analysis of the photovoltaic performance of Sb₂Se₃-/CdS-based solar cells. We construct a specific device that may be produced in any lab using the thermal evaporation technique. Experimentally, efficiency is improved from 0.96% to 1.36% by varying the absorber’s thickness. Experimental information on Sb₂Se₃, such as the band gap and thickness, is used in the simulation to check the performance of the device after the optimization of various other parameters, including the series and shunt resistance, and a theoretical maximum efficiency of 4.42% is achieved. Further, the device’s efficiency is improved to 11.27% by optimizing the various parameters of the active layer. It thus is demonstrated that the band gap and thickness of active layers strongly affect the overall performance of a photovoltaic device. Full article

(This article belongs to the Special Issue Advance in Energy Harvesters/Nanogenerators and Self-Powered Sensors II)

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14 pages, 2743 KiB

Open AccessArticle

The Effect of C60 and Pentacene Adsorbates on the Electrical Properties of CVD Graphene on SiO₂

by Jacopo Oswald, Davide Beretta, Michael Stiefel, Roman Furrer, Dominique Vuillaume and Michel Calame

Nanomaterials 2023, 13(6), 1134; https://doi.org/10.3390/nano13061134 - 22 Mar 2023

Cited by 2 | Viewed by 1725

Abstract

Graphene is an excellent 2D material for vertical organic transistors electrodes due to its weak electrostatic screening and field-tunable work function, in addition to its high conductivity, flexibility and optical transparency. Nevertheless, the interaction between graphene and other carbon-based materials, including small organic [...] Read more.

Graphene is an excellent 2D material for vertical organic transistors electrodes due to its weak electrostatic screening and field-tunable work function, in addition to its high conductivity, flexibility and optical transparency. Nevertheless, the interaction between graphene and other carbon-based materials, including small organic molecules, can affect the graphene electrical properties and therefore, the device performances. This work investigates the effects of thermally evaporated C60 (n-type) and Pentacene (p-type) thin films on the in-plane charge transport properties of large area CVD graphene under vacuum. This study was performed on a population of 300 graphene field effect transistors. The output characteristic of the transistors revealed that a C60 thin film adsorbate increased the graphene hole density by (1.65 ± 0.36) × 10¹² cm⁻², whereas a Pentacene thin film increased the graphene electron density by (0.55 ± 0.54) × 10¹² cm⁻². Hence, C60 induced a graphene Fermi energy downshift of about 100 meV, while Pentacene induced a Fermi energy upshift of about 120 meV. In both cases, the increase in charge carriers was accompanied by a reduced charge mobility, which resulted in a larger graphene sheet resistance of about 3 kΩ at the Dirac point. Interestingly, the contact resistance, which varied in the range 200 Ω–1 kΩ, was not significantly affected by the deposition of the organic molecules. Full article

(This article belongs to the Special Issue Carbon-Based Multifunctional Nanomaterials: Synthesis, Properties and Application)

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9 pages, 2992 KiB

Open AccessArticle

Multi-Parametric Birefringence Control in Ultrashort-Pulse Laser-Inscribed Nanolattices in Fluorite

by Sergey Kudryashov, Alexey Rupasov, Mikhail Smayev, Pavel Danilov, Evgeny Kuzmin, Irina Mushkarina, Alexey Gorevoy, Anna Bogatskaya and Alexander Zolot’ko

Nanomaterials 2023, 13(6), 1133; https://doi.org/10.3390/nano13061133 - 22 Mar 2023

Viewed by 1287

Abstract

An ultrashort-pulse laser inscription of embedded birefringent microelements was performed inside bulk fluorite in pre-filamentation (geometrical focusing) and filamentation regimes as a function of laser wavelength, pulsewidth and energy. The resulting elements composed of anisotropic nanolattices were characterized by retardance (Ret) [...] Read more.

An ultrashort-pulse laser inscription of embedded birefringent microelements was performed inside bulk fluorite in pre-filamentation (geometrical focusing) and filamentation regimes as a function of laser wavelength, pulsewidth and energy. The resulting elements composed of anisotropic nanolattices were characterized by retardance (Ret) and thickness (T) quantities, using polarimetric and 3D-scanning confocal photoluminescence microscopy, respectively. Both parameters exhibit a monotonous increase versus pulse energy, going over a maximum at 1-ps pulsewidth at 515 nm, but decrease versus laser pulsewidth at 1030 nm. The resulting refractive-index difference (RID) Δn = Ret/T ~ 1 × 10⁻³ remains almost constant versus pulse energy and slightly decreases at a higher pulsewidth, generally being higher at 515 nm. The birefringent microelements were visualized using scanning electron microscopy and chemically characterized using energy-dispersion X-ray spectroscopy, indicating the increase of calcium and the contrary decrease of fluorine inside them due to the non-ablative inscription character. Dynamic far-field optical diffraction of the inscribing ultrashort laser pulses also demonstrated the accumulative inscription character, depending on the pulse energy and the laser exposure. Our findings revealed the underlying optical and material inscription processes and demonstrated the robust longitudinal homogeneity of the inscribed birefringent microstructures and the facile scalability of their thickness-dependent retardance. Full article

(This article belongs to the Special Issue Research on Nano-Lattice)

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16 pages, 1752 KiB

Open AccessEditor’s ChoiceReview

The Potential of ICP-MS as a Complementary Tool in Nanoparticle–Protein Corona Analysis

by Ana Fuentes-Cervantes, Julia Ruiz Allica, Francisco Calderón Celis, José M. Costa-Fernández and Jorge Ruiz Encinar

Nanomaterials 2023, 13(6), 1132; https://doi.org/10.3390/nano13061132 - 22 Mar 2023

Cited by 7 | Viewed by 2030

Abstract

The prolific applicability of nanomaterials has made them a common citizen in biological systems, where they interact with proteins forming a biological corona complex. These complexes drive the interaction of nanomaterials with and within the cells, bringing forward numerous potential applications in nanobiomedicine, [...] Read more.

The prolific applicability of nanomaterials has made them a common citizen in biological systems, where they interact with proteins forming a biological corona complex. These complexes drive the interaction of nanomaterials with and within the cells, bringing forward numerous potential applications in nanobiomedicine, but also arising toxicological issues and concerns. Proper characterization of the protein corona complex is a great challenge typically handled with the combination of several techniques. Surprisingly, despite inductively coupled plasma mass spectrometry (ICP-MS) being a powerful quantitative technique whose application in nanomaterials characterization and quantification has been consolidated in the last decade, its application to nanoparticle–protein corona studies is scarce. Furthermore, in the last decades, ICP-MS has experienced a turning point in its capabilities for protein quantification through sulfur detection, hence becoming a generic quantitative detector. In this regard, we would like to introduce the potential of ICP-MS in the nanoparticle protein corona complex characterization and quantification complementary to current methods and protocols. Full article

(This article belongs to the Special Issue ICP-MS-Based Characterization and Quantification of Nano- and Microstructures)

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31 pages, 1329 KiB

Open AccessReview

The Impact of Cavities in Different Thermal Applications of Nanofluids: A Review

by Mudasar Zafar, Hamzah Sakidin, Mikhail Sheremet, Iskandar Dzulkarnain, Roslinda Mohd Nazar, Abida Hussain, Zafar Said, Farkhanda Afzal, Abdullah Al-Yaari, Muhammad Saad Khan and Javed Akbar Khan

Nanomaterials 2023, 13(6), 1131; https://doi.org/10.3390/nano13061131 - 22 Mar 2023

Cited by 11 | Viewed by 1866

Abstract

Nanofluids and nanotechnology are very important in enhancing heat transfer due to the thermal conductivity of their nanoparticles, which play a vital role in heat transfer applications. Researchers have used cavities filled with nanofluids for two decades to increase the heat-transfer rate. This [...] Read more.

Nanofluids and nanotechnology are very important in enhancing heat transfer due to the thermal conductivity of their nanoparticles, which play a vital role in heat transfer applications. Researchers have used cavities filled with nanofluids for two decades to increase the heat-transfer rate. This review also highlights a variety of theoretical and experimentally measured cavities by exploring the following parameters: the significance of cavities in nanofluids, the effects of nanoparticle concentration and nanoparticle material, the influence of the inclination angle of cavities, heater and cooler effects, and magnetic field effects in cavities. The different shapes of the cavities have several advantages in multiple applications, e.g., L-shaped cavities used in the cooling systems of nuclear and chemical reactors and electronic components. Open cavities such as ellipsoidal, triangular, trapezoidal, and hexagonal are applied in electronic equipment cooling, building heating and cooling, and automotive applications. Appropriate cavity design conserves energy and produces attractive heat-transfer rates. Circular microchannel heat exchangers perform best. Despite the high performance of circular cavities in micro heat exchangers, square cavities have more applications. The use of nanofluids has been found to improve thermal performance in all the cavities studied. According to the experimental data, nanofluid use has been proven to be a dependable solution for enhancing thermal efficiency. To improve performance, it is suggested that research focus on different shapes of nanoparticles less than 10 nm with the same design of the cavities in microchannel heat exchangers and solar collectors. Full article

(This article belongs to the Special Issue Applications of Nanofluids – II)

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30 pages, 4022 KiB

Open AccessReview

Inorganic Nanomaterials Used in Anti-Cancer Therapies:Further Developments

by Olga Długosz, Wiktoria Matyjasik, Gabriela Hodacka, Krzysztof Szostak, Julia Matysik, Patrycja Krawczyk, Anna Piasek, Jolanta Pulit-Prociak and Marcin Banach

Nanomaterials 2023, 13(6), 1130; https://doi.org/10.3390/nano13061130 - 22 Mar 2023

Cited by 3 | Viewed by 2393

Abstract

In this article, we provide an overview of the progress of scientists working to improve the quality of life of cancer patients. Among the known methods, cancer treatment methods focusing on the synergistic action of nanoparticles and nanocomposites have been proposed and described. [...] Read more.

In this article, we provide an overview of the progress of scientists working to improve the quality of life of cancer patients. Among the known methods, cancer treatment methods focusing on the synergistic action of nanoparticles and nanocomposites have been proposed and described. The application of composite systems will allow precise delivery of therapeutic agents to cancer cells without systemic toxicity. The nanosystems described could be used as a high-efficiency photothermal therapy system by exploiting the properties of the individual nanoparticle components, including their magnetic, photothermal, complex, and bioactive properties. By combining the advantages of the individual components, it is possible to obtain a product that would be effective in cancer treatment. The use of nanomaterials to produce both drug carriers and those active substances with a direct anti-cancer effect has been extensively discussed. In this section, attention is paid to metallic nanoparticles, metal oxides, magnetic nanoparticles, and others. The use of complex compounds in biomedicine is also described. A group of compounds showing significant potential in anti-cancer therapies are natural compounds, which have also been discussed. Full article

(This article belongs to the Special Issue Recent Insights on Metal Nanomaterials for Biomedicine and Health Care)

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16 pages, 3398 KiB

Open AccessArticle

Functionalized Biochars as Supports for Ru/C Catalysts: Tunable and Efficient Materials for γ-Valerolactone Production

by Charf Eddine Bounoukta, Cristina Megías-Sayago, Juan Carlos Navarro, Fatima Ammari, Svetlana Ivanova, Miguel Ángel Centeno and Jose Antonio Odriozola

Nanomaterials 2023, 13(6), 1129; https://doi.org/10.3390/nano13061129 - 22 Mar 2023

Cited by 3 | Viewed by 1565

Abstract

Cotton stalks-based biochars were prepared and used to synthetize Ru-supported catalysts for selective production of γ-valerolactone from levulinic acid in aqueous media. Different biochars’ pre-treatments (HNO₃, ZnCl₂, CO₂ or a combination of them) were carried out to activate [...] Read more.

Cotton stalks-based biochars were prepared and used to synthetize Ru-supported catalysts for selective production of γ-valerolactone from levulinic acid in aqueous media. Different biochars’ pre-treatments (HNO₃, ZnCl₂, CO₂ or a combination of them) were carried out to activate the final carbonaceous support. Nitric acid treatment resulted in microporous biochars with high surface area, whereas the chemical activation with ZnCl₂ substantially increases the mesoporous surface. The combination of both treatments led to a support with exceptional textural properties allowing the preparation of Ru/C catalyst with 1422 m²/g surface area, 1210 m²/g of it being a mesoporous surface. The impact of the biochars’ pre-treatments on the catalytic performance of Ru-based catalysts is fully discussed. Full article

(This article belongs to the Special Issue Application of Porous Nanomaterials in Energy Storage and Catalysis)

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14 pages, 3096 KiB

Open AccessArticle

CrPS₄ Nanoflakes as Stable Direct-Band-Gap 2D Materials for Ultrafast Pulse Laser Applications

by Wenyao Zhang, Yu Zhang, Xudong Leng, Qun Jing and Qiao Wen

Nanomaterials 2023, 13(6), 1128; https://doi.org/10.3390/nano13061128 - 22 Mar 2023

Cited by 2 | Viewed by 2089

Abstract

Two-dimensional (2D) materials have attracted considerable attention due to their potential for generating ultrafast pulsed lasers. Unfortunately, the poor stability of most layered 2D materials under air exposure leads to increased fabrication costs; this has limited their development for practical applications. In this [...] Read more.

Two-dimensional (2D) materials have attracted considerable attention due to their potential for generating ultrafast pulsed lasers. Unfortunately, the poor stability of most layered 2D materials under air exposure leads to increased fabrication costs; this has limited their development for practical applications. In this paper, we describe the successful preparation of a novel, air-stable, and broadband saturable absorber (SA), the metal thiophosphate CrPS₄, using a simple and cost-effective liquid exfoliation method. The van der Waals crystal structure of CrPS₄ consists of chains of CrS₆ units interconnected by phosphorus. In this study, we calculated the electronic band structures of CrPS₄, revealing a direct band gap. The nonlinear saturable absorption properties, which were investigated using the P-scan technique at 1550 nm, revealed that CrPS₄-SA had a modulation depth of 12.2% and a saturation intensity of 463 MW/cm². Integration of the CrPS₄-SA into Yb-doped fiber and Er-doped fiber laser cavities led to mode-locking for the first time, resulting in the shortest pulse durations of 298 ps and 500 fs at 1 and 1.5 µm, respectively. These results indicate that CrPS₄ has great potential for broadband ultrafast photonic applications and could be developed into an excellent candidate for SA devices, providing new directions in the search for stable SA materials and for their design. Full article

(This article belongs to the Special Issue 2D Structured Materials: Synthesis, Properties and Applications)

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14 pages, 2291 KiB

Open AccessArticle

Effects of Top and Bottom Electrodes Materials and Operating Ambiance on the Characteristics of MgF_x Based Bipolar RRAMs

by Nayan C. Das, Yong-Pyo Kim, Sung-Min Hong and Jae-Hyung Jang

Nanomaterials 2023, 13(6), 1127; https://doi.org/10.3390/nano13061127 - 22 Mar 2023

Cited by 3 | Viewed by 1724

Abstract

The effects of electrode materials (top and bottom) and the operating ambiances (open-air and vacuum) on the MgF_x-based resistive random-access memory (RRAM) devices are studied. Experiment results show that the device’s performance and stability depend on the difference between the top [...] Read more.

The effects of electrode materials (top and bottom) and the operating ambiances (open-air and vacuum) on the MgF_x-based resistive random-access memory (RRAM) devices are studied. Experiment results show that the device’s performance and stability depend on the difference between the top and bottom electrodes’ work functions. Devices are robust in both environments if the work function difference between the bottom and top electrodes is greater than or equal to 0.70 eV. The operating environment-independent device performance depends on the surface roughness of the bottom electrode materials. Reducing the bottom electrodes’ surface roughness will reduce moisture absorption, minimizing the impact of the operating environment. Ti/MgF_x/p⁺-Si memory devices with the minimum surface roughness of the p⁺-Si bottom electrode show operating environment-independent electroforming-free stable resistive switching properties. The stable memory devices show promising data retentions of >10⁴ s in both environments with DC endurance properties of more than 100 cycles. Full article

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

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10 pages, 1745 KiB

Open AccessArticle

Temperature-Dependent Anisotropic Refractive Index in β-Ga₂O₃: Application in Interferometric Thermometers

by Daniel Carrasco, Eva Nieto-Pinero, Manuel Alonso-Orts, Rosalía Serna, Jose M. San Juan, María L. Nó, Jani Jesenovec, John S. McCloy, Emilio Nogales and Bianchi Méndez

Nanomaterials 2023, 13(6), 1126; https://doi.org/10.3390/nano13061126 - 21 Mar 2023

Cited by 4 | Viewed by 1721

Abstract

An accurate knowledge of the optical properties of β-Ga₂O₃ is key to developing the full potential of this oxide for photonics applications. In particular, the dependence of these properties on temperature is still being studied. Optical micro- and nanocavities are [...] Read more.

An accurate knowledge of the optical properties of β-Ga₂O₃ is key to developing the full potential of this oxide for photonics applications. In particular, the dependence of these properties on temperature is still being studied. Optical micro- and nanocavities are promising for a wide range of applications. They can be created within microwires and nanowires via distributed Bragg reflectors (DBR), i.e., periodic patterns of the refractive index in dielectric materials, acting as tunable mirrors. In this work, the effect of temperature on the anisotropic refractive index of β-Ga₂O₃ n(λ,T) was analyzed with ellipsometry in a bulk crystal, and temperature-dependent dispersion relations were obtained, with them being fitted to Sellmeier formalism in the visible range. Micro-photoluminescence (μ-PL) spectroscopy of microcavities that developed within Cr-doped β-Ga₂O₃ nanowires shows the characteristic thermal shift of red–infrared Fabry–Perot optical resonances when excited with different laser powers. The origin of this shift is mainly related to the variation in the temperature of the refractive index. A comparison of these two experimental results was performed by finite-difference time-domain (FDTD) simulations, considering the exact morphology of the wires and the temperature-dependent, anisotropic refractive index. The shifts caused by temperature variations observed by μ-PL are similar, though slightly larger than those obtained with FDTD when implementing the n(λ,T) obtained with ellipsometry. The thermo-optic coefficient was calculated. Full article

(This article belongs to the Special Issue Semiconductor Nanowires: From Synthesis and Characterization to Devices)

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13 pages, 5228 KiB

Open AccessArticle

Facile Synthesis of Battery-Type CuMn₂O₄ Nanosheet Arrays on Ni Foam as an Efficient Binder-Free Electrode Material for High-Rate Supercapacitors

by Chandu V. V. Muralee Gopi, R. Ramesh, Rajangam Vinodh, Salem Alzahmi and Ihab M. Obaidat

Nanomaterials 2023, 13(6), 1125; https://doi.org/10.3390/nano13061125 - 21 Mar 2023

Cited by 6 | Viewed by 1915

Abstract

The development of battery-type electrode materials with hierarchical nanostructures has recently gained considerable attention in high-rate hybrid supercapacitors. For the first time, in the present study novel hierarchical CuMn₂O₄ nanosheet arrays (NSAs) nanostructures are developed using a one-step hydrothermal route [...] Read more.

The development of battery-type electrode materials with hierarchical nanostructures has recently gained considerable attention in high-rate hybrid supercapacitors. For the first time, in the present study novel hierarchical CuMn₂O₄ nanosheet arrays (NSAs) nanostructures are developed using a one-step hydrothermal route on a nickel foam substrate and utilized as an enhanced battery-type electrode material for supercapacitors without the need of binders or conducting polymer additives. X-ray diffraction, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques are used to study the phase, structural, and morphological characteristics of the CuMn₂O₄ electrode. SEM and TEM studies show that CuMn₂O₄ exhibits a nanosheet array morphology. According to the electrochemical data, CuMn₂O₄ NSAs give a Faradic battery-type redox activity that differs from the behavior of carbon-related materials (such as activated carbon, reduced graphene oxide, graphene, etc.). The battery-type CuMn₂O₄ NSAs electrode showed an excellent specific capacity of 125.56 mA h g⁻¹ at 1 A g⁻¹ with a remarkable rate capability of 84.1%, superb cycling stability of 92.15% over 5000 cycles, good mechanical stability and flexibility, and low internal resistance at the interface of electrode and electrolyte. Due to their excellent electrochemical properties, high-performance CuMn₂O₄ NSAs-like structures are prospective battery-type electrodes for high-rate supercapacitors. Full article

(This article belongs to the Special Issue Nanostructured Electrodes for High-Performance Supercapacitors and Batteries)

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12 pages, 19286 KiB

Open AccessArticle

Remarkable Pyro-Catalysis of g-C₃N₄ Nanosheets for Dye Decoloration under Room-Temperature Cold–Hot Cycle Excitation

by Zheng Wu, Xiaoyu Shi, Tingting Liu, Xiaoli Xu, Hongjian Yu, Yan Zhang, Laishun Qin, Xiaoping Dong and Yanmin Jia

Nanomaterials 2023, 13(6), 1124; https://doi.org/10.3390/nano13061124 - 21 Mar 2023

Cited by 7 | Viewed by 1299

Abstract

Pyroelectric materials have the ability to convert the environmental cold–hot thermal energy such as day–night temperature alternation into electrical energy. The novel pyro-catalysis technology can be designed and realized on the basis of the product coupling between pyroelectric and electrochemical redox effects, which [...] Read more.

Pyroelectric materials have the ability to convert the environmental cold–hot thermal energy such as day–night temperature alternation into electrical energy. The novel pyro-catalysis technology can be designed and realized on the basis of the product coupling between pyroelectric and electrochemical redox effects, which is helpful for the actual dye decomposition. The organic two-dimensional (2D) graphic carbon nitride (g-C₃N₄), as an analogue of graphite, has attracted considerable interest in the field of material science; however, its pyroelectric effect has rarely been reported. In this work, the remarkable pyro-catalytic performance was achieved in the 2D organic g-C₃N₄ nanosheet catalyst materials under the continuous room-temperature cold–hot thermal cycling excitation from 25 °C to 60 °C. The pyro-catalytic RhB dye decoloration efficiency of the 2D organic g-C₃N₄ can reach ~92.6%. Active species such as the superoxide radicals and hydroxyl radicals are observed as the intermediate products in the pyro-catalysis process of the 2D organic g-C₃N₄ nanosheets. The pyro-catalysis of the 2D organic g-C₃N₄ nanosheets provides efficient technology for wastewater treatment applications, utilizing the ambient cold–hot alternation temperature variations in future. Full article

(This article belongs to the Special Issue The Properties of Functional Nanomaterials and Their Energy and Environmental Applications)

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13 pages, 3185 KiB

Open AccessArticle

The Surface Properties of Implant Materials by Deposition of High-Entropy Alloys (HEAs)

by Khalid Usman, Doori Kang, Geonwoo Jeong, Khurshed Alam, Athira Raveendran, Jinhui Ser, Woohyung Jang and Hoonsung Cho

Nanomaterials 2023, 13(6), 1123; https://doi.org/10.3390/nano13061123 - 21 Mar 2023

Cited by 3 | Viewed by 1966

Abstract

High-entropy alloys (HEAs) contain more than five alloying elements in a composition range of 5–35% and with slight atomic size variation. Recent narrative studies on HEA thin films and their synthesis through deposition techniques such as sputtering have highlighted the need for determining [...] Read more.

High-entropy alloys (HEAs) contain more than five alloying elements in a composition range of 5–35% and with slight atomic size variation. Recent narrative studies on HEA thin films and their synthesis through deposition techniques such as sputtering have highlighted the need for determining the corrosion behaviors of such alloys used as biomaterials, for example, in implants. Coatings composed of biocompatible elements such as titanium, cobalt, chrome, nickel, and molybdenum at the nominal composition of Co₃₀Cr₂₀Ni₂₀Mo₂₀Ti₁₀ were synthesized by means of high-vacuum radiofrequency magnetron (HVRF) sputtering. In scanning electron microscopy (SEM) analysis, the coating samples deposited with higher ion densities were thicker than those deposited with lower ion densities (thin films). The X-ray diffraction (XRD) results of the thin films heat treated at higher temperatures, i.e., 600 and 800 °C, revealed a low degree of crystallinity. In thicker coatings and samples without heat treatment, the XRD peaks were amorphous. The samples coated at lower ion densities, i.e., 20 µAcm⁻², and not subjected to heat treatment yielded superior results in terms of corrosion and biocompatibility among all the samples. Heat treatment at higher temperatures led to alloy oxidation, thus compromising the corrosion property of the deposited coatings. Full article

(This article belongs to the Special Issue Advanced 2D Materials for Emerging Application)

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20 pages, 16628 KiB

Open AccessArticle

Enhanced Tribological Performance of Low-Friction Nanocomposite WSe_xS_y/NP-W Coatings Prepared by Reactive PLD

by Vyacheslav Fominski, Dmitry Fominski, Maxim Demin, Roman Romanov and Alexander Goikhman

Nanomaterials 2023, 13(6), 1122; https://doi.org/10.3390/nano13061122 - 21 Mar 2023

Cited by 3 | Viewed by 1732

Abstract

A novel laser-based method for producing nanocomposite coatings consisting of a tungsten sulfoselenide (WSe_xS_y) matrix and W nanoparticles (NP-W) was developed. Pulsed laser ablation of WSe₂ was carried out in H₂S gas under appropriate laser fluence [...] Read more.

A novel laser-based method for producing nanocomposite coatings consisting of a tungsten sulfoselenide (WSe_xS_y) matrix and W nanoparticles (NP-W) was developed. Pulsed laser ablation of WSe₂ was carried out in H₂S gas under appropriate laser fluence and reactive gas pressure. It was found that moderate sulfur doping (S/Se ~0.2–0.3) leads to significant improvement in the tribological properties of WSe_xS_y/NP-W coatings at room temperature. Changes in the coatings during tribotesting depended on the load on the counter body. The lowest coefficient of friction (~0.02) with a high wear resistance was observed in a N₂ environment at an increased load (5 N), resulting from certain structural and chemical changes in the coatings. A tribofilm with a layered atomic packing was observed in the surface layer of the coating. The incorporation of nanoparticles into the coating increased its hardness, which may have influenced the formation of the tribofilm. The initial matrix composition, which had a higher content of chalcogen atoms ((Se + S)/W~2.6–3.5), was altered in the tribofilm to a composition close to the stoichiometric one ((Se + S)/W~1.9). W nanoparticles were ground and retained under the tribofilm, which impacted the effective contact area with the counter body. Changes in the tribotesting conditions—lowering the temperature in a N₂ environment—resulted in considerable deterioration of the tribological properties of these coatings. Only coating with a higher S content that was obtained at increased H₂S pressure exhibited remarkable wear resistance and a low coefficient of friction, measuring 0.06, even under complicated conditions. Full article

(This article belongs to the Special Issue Laser Synthesis and Processing of Nanostructured Materials)

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20 pages, 5628 KiB

Open AccessArticle

Covalent Triazine Framework C₆N₆ as an Electrochemical Sensor for Hydrogen-Containing Industrial Pollutants. A DFT Study

by Hassan H. Hammud, Muhammad Yar, Imene Bayach and Khurshid Ayub

Nanomaterials 2023, 13(6), 1121; https://doi.org/10.3390/nano13061121 - 21 Mar 2023

Cited by 3 | Viewed by 1503

Abstract

Industrial pollutants pose a serious threat to ecosystems. Hence, there is a need to search for new efficient sensor materials for the detection of pollutants. In the current study, we explored the electrochemical sensing potential of a C₆N₆ sheet for [...] Read more.

Industrial pollutants pose a serious threat to ecosystems. Hence, there is a need to search for new efficient sensor materials for the detection of pollutants. In the current study, we explored the electrochemical sensing potential of a C₆N₆ sheet for H-containing industrial pollutants (HCN, H₂S, NH₃ and PH₃) through DFT simulations. The adsorption of industrial pollutants over C₆N₆ occurs through physisorption, with adsorption energies ranging from −9.36 kcal/mol to −16.46 kcal/mol. The non-covalent interactions of analyte@C₆N₆ complexes are quantified by symmetry adapted perturbation theory (SAPT0), quantum theory of atoms in molecules (QTAIM) and non-covalent interaction (NCI) analyses. SAPT0 analyses show that electrostatic and dispersion forces play a dominant role in the stabilization of analytes over C₆N₆ sheets. Similarly, NCI and QTAIM analyses also verified the results of SAPT0 and interaction energy analyses. The electronic properties of analyte@C₆N₆ complexes are investigated by electron density difference (EDD), natural bond orbital analyses (NBO) and frontier molecular orbital analyses (FMO). Charge is transferred from the C₆N₆ sheet to HCN, H₂S, NH₃ and PH₃. The highest exchange of charge is noted for H₂S (−0.026 e⁻). The results of FMO analyses show that the interaction of all analytes results in changes in the E_H-L gap of the C₆N₆ sheet. However, the highest decrease in the E_H-L gap (2.58 eV) is observed for the NH₃@C₆N₆ complex among all studied analyte@C₆N₆ complexes. The orbital density pattern shows that the HOMO density is completely concentrated on NH₃, while the LUMO density is centred on the C₆N₆ surface. Such a type of electronic transition results in a significant change in the E_H-L gap. Thus, it is concluded that C₆N₆ is highly selective towards NH₃ compared to the other studied analytes. Full article

(This article belongs to the Special Issue Nanomaterials in Sensing Applications)

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10 pages, 5308 KiB

Open AccessArticle

Low Threshold Current and Polarization-Stabilized 795 nm Vertical-Cavity Surface-Emitting Lasers

by Qiuxue Fu, Yurun Sun, Suzhen Yu, Ancheng Wang, Jiajing Yin, Yongming Zhao and Jianrong Dong

Nanomaterials 2023, 13(6), 1120; https://doi.org/10.3390/nano13061120 - 21 Mar 2023

Cited by 1 | Viewed by 1356

Abstract

Low threshold current and polarization-stabilized 795 nm vertical-cavity surface-emitting lasers (VCSELs) are fabricated by integrating a surface grating of high polarization selectivity and high reflectivity. The rigorous coupled-wave analysis method is used to design the surface grating. For the devices with a grating [...] Read more.

Low threshold current and polarization-stabilized 795 nm vertical-cavity surface-emitting lasers (VCSELs) are fabricated by integrating a surface grating of high polarization selectivity and high reflectivity. The rigorous coupled-wave analysis method is used to design the surface grating. For the devices with a grating period of 500 nm, a grating depth of ~150 nm, and a diameter of the surface grating region of 5 μm, a threshold current of 0.4 mA and an orthogonal polarization suppression ratio (OPSR) of 19.56 dB are obtained. The emission wavelength of 795 nm of a single transverse mode VCSEL is achieved at a temperature of 85 °C under an injection current of 0.9 mA. In addition, experiments demonstrate that the threshold and output power also depended on the size of the grating region. Full article

(This article belongs to the Special Issue Molecular Beam Epitaxy Growth of Quantum Wires and Quantum Dots)

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8 pages, 513 KiB

Open AccessEditor’s ChoiceArticle

Fine Structure Splitting of Phonon-Assisted Excitonic Transition in (PEA)₂PbI₄ Two-Dimensional Perovskites

by Katarzyna Posmyk, Mateusz Dyksik, Alessandro Surrente, Katarzyna Zalewska, Maciej Śmiertka, Ewelina Cybula, Watcharaphol Paritmongkol, William A. Tisdale, Paulina Plochocka and Michał Baranowski

Nanomaterials 2023, 13(6), 1119; https://doi.org/10.3390/nano13061119 - 21 Mar 2023

Cited by 5 | Viewed by 2396

Abstract

Two-dimensional van der Waals materials exhibit particularly strong excitonic effects, which causes them to be an exceptionally interesting platform for the investigation of exciton physics. A notable example is the two-dimensional Ruddlesden–Popper perovskites, where quantum and dielectric confinement together with soft, polar, and [...] Read more.

Two-dimensional van der Waals materials exhibit particularly strong excitonic effects, which causes them to be an exceptionally interesting platform for the investigation of exciton physics. A notable example is the two-dimensional Ruddlesden–Popper perovskites, where quantum and dielectric confinement together with soft, polar, and low symmetry lattice create a unique background for electron and hole interaction. Here, with the use of polarization-resolved optical spectroscopy, we have demonstrated that the simultaneous presence of tightly bound excitons, together with strong exciton–phonon coupling, allows for observing the exciton fine structure splitting of the phonon-assisted transitions of two-dimensional perovskite (PEA)

_{2}

PbI

_{4}

, where PEA stands for phenylethylammonium. We demonstrate that the phonon-assisted sidebands characteristic for (PEA)

_{2}

PbI

_{4}

are split and linearly polarized, mimicking the characteristics of the corresponding zero-phonon lines. Interestingly, the splitting of differently polarized phonon-assisted transitions can be different from that of the zero-phonon lines. We attribute this effect to the selective coupling of linearly polarized exciton states to non-degenerate phonon modes of different symmetries resulting from the low symmetry of (PEA)

_{2}

PbI

_{4}

lattice. Full article

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

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14 pages, 1591 KiB

Open AccessEditor’s ChoiceArticle

A DFT Study of Ruthenium fcc Nano-Dots: Size-Dependent Induced Magnetic Moments

by Marietjie J. Ungerer and Nora H. de Leeuw

Nanomaterials 2023, 13(6), 1118; https://doi.org/10.3390/nano13061118 - 21 Mar 2023

Cited by 2 | Viewed by 1755

Abstract

Many areas of electronics, engineering and manufacturing rely on ferromagnetic materials, including iron, nickel and cobalt. Very few other materials have an innate magnetic moment rather than induced magnetic properties, which are more common. However, in a previous study of ruthenium nanoparticles, the [...] Read more.

Many areas of electronics, engineering and manufacturing rely on ferromagnetic materials, including iron, nickel and cobalt. Very few other materials have an innate magnetic moment rather than induced magnetic properties, which are more common. However, in a previous study of ruthenium nanoparticles, the smallest nano-dots showed significant magnetic moments. Furthermore, ruthenium nanoparticles with a face-centred cubic (fcc) packing structure exhibit high catalytic activity towards several reactions and such catalysts are of special interest for the electrocatalytic production of hydrogen. Previous calculations have shown that the energy per atom resembles that of the bulk energy per atom when the surface-to-bulk ratio < 1, but in its smallest form, nano-dots exhibit a range of other properties. Therefore, in this study, we have carried out calculations based on the density functional theory (DFT) with long-range dispersion corrections DFT-D3 and DFT-D3-(BJ) to systematically investigate the magnetic moments of two different morphologies and various sizes of Ru nano-dots in the fcc phase. To confirm the results obtained by the plane-wave DFT methodologies, additional atom-centred DFT calculations were carried out on the smallest nano-dots to establish accurate spin-splitting energetics. Surprisingly, we found that in most cases, the high spin electronic structures had the most favourable energies and were hence the most stable. Full article

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

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14 pages, 13322 KiB

Open AccessArticle

Can Superhydrophobic PET Surfaces Prevent Bacterial Adhesion?

by Tugce Caykara, Sara Fernandes, Adelaide Braga, Joana Rodrigues, Ligia R. Rodrigues and Carla Joana Silva

Nanomaterials 2023, 13(6), 1117; https://doi.org/10.3390/nano13061117 - 21 Mar 2023

Cited by 2 | Viewed by 1542

Abstract

Prevention of bacterial adhesion is a way to reduce and/or avoid biofilm formation, thus restraining its associated infections. The development of repellent anti-adhesive surfaces, such as superhydrophobic surfaces, can be a strategy to avoid bacterial adhesion. In this study, a polyethylene terephthalate (PET) [...] Read more.

Prevention of bacterial adhesion is a way to reduce and/or avoid biofilm formation, thus restraining its associated infections. The development of repellent anti-adhesive surfaces, such as superhydrophobic surfaces, can be a strategy to avoid bacterial adhesion. In this study, a polyethylene terephthalate (PET) film was modified by in situ growth of silica nanoparticles (NPs) to create a rough surface. The surface was further modified with fluorinated carbon chains to increase its hydrophobicity. The modified PET surfaces presented a pronounced superhydrophobic character, showing a water contact angle of 156° and a roughness of 104 nm (a considerable increase comparing with the 69° and 4.8 nm obtained for the untreated PET). Scanning Electron Microscopy was used to evaluate the modified surfaces morphology, further confirming its successful modification with nanoparticles. Additionally, a bacterial adhesion assay using an Escherichia coli expressing YadA, an adhesive protein from Yersinia so-called Yersinia adhesin A, was used to assess the anti-adhesive potential of the modified PET. Contrarily to what was expected, adhesion of E. coli YadA was found to increase on the modified PET surfaces, exhibiting a clear preference for the crevices. This study highlights the role of material micro topography as an important attribute when considering bacterial adhesion. Full article

(This article belongs to the Special Issue Organic and Inorganic Nanostructured Composites for Medical Application)

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6 pages, 876 KiB

Open AccessEditorial

Defect Engineering of Nanomaterials for Catalysis

by Yang Luo and Yinghong Wu

Nanomaterials 2023, 13(6), 1116; https://doi.org/10.3390/nano13061116 - 21 Mar 2023

Cited by 2 | Viewed by 1850

Abstract

Defect chemistry is a branch of materials science that deals with the study of the properties and behavior of defects in crystalline solids [...] Full article

(This article belongs to the Special Issue Trends and Recent Advances in Defective Nanocatalysts)

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14 pages, 4690 KiB

Open AccessEditor’s ChoiceArticle

The Application of Nanofibrous Resonant Membranes for Room Acoustics

by Klara Kalinova

Nanomaterials 2023, 13(6), 1115; https://doi.org/10.3390/nano13061115 - 21 Mar 2023

Cited by 1 | Viewed by 1159

Abstract

Solitary sound absorbing elements exist; however, their construction is massive and heavy, which largely limits their use. These elements are generally made of porous materials that serve to reduce the amplitude of the reflected sound waves. Materials based on the resonance principle (oscillating [...] Read more.

Solitary sound absorbing elements exist; however, their construction is massive and heavy, which largely limits their use. These elements are generally made of porous materials that serve to reduce the amplitude of the reflected sound waves. Materials based on the resonance principle (oscillating membranes, plates, and Helmholtz’s resonators) can also be used for sound absorption. A limitation of these elements is the absorption of a very narrow sound band to which these elements are “tuned”. For other frequencies, the absorption is very low. The aim of the solution is to achieve a high sound absorption efficiency at a very low weight. A nanofibrous membrane was used to create high sound absorption in synergy with special grids working as a cavity resonator. Prototypes of the nanofibrous resonant membrane on a grid with a thickness of 2 mm and an air gap of 50 mm already showed a high level of sound absorption (0.6–0.8) at a frequency of 300 Hz, which is a very unique result. Since acoustic elements, i.e., lighting, tiles, and ceilings, are designed for interiors, an essential part of the research is also the achievement of the lighting function and the emphasis on aesthetic design. Full article

(This article belongs to the Special Issue Electrospinning for Nanofiber Membrane Fabrication: Challenges and Applications)

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8 pages, 2350 KiB

Open AccessCommunication

Great Potential of Si-Te Ovonic Threshold Selector in Electrical Performance and Scalability

by Renjie Wu, Yuting Sun, Shuhao Zhang, Zihao Zhao and Zhitang Song

Nanomaterials 2023, 13(6), 1114; https://doi.org/10.3390/nano13061114 - 21 Mar 2023

Cited by 2 | Viewed by 1471

Abstract

The selector is an indispensable section of the phase change memory (PCM) chip, where it not only suppresses the crosstalk, but also provides high on-current to melt the incorporated phase change material. In fact, the ovonic threshold switching (OTS) selector is utilized in [...] Read more.

The selector is an indispensable section of the phase change memory (PCM) chip, where it not only suppresses the crosstalk, but also provides high on-current to melt the incorporated phase change material. In fact, the ovonic threshold switching (OTS) selector is utilized in 3D stacking PCM chips by virtue of its high scalability and driving capability. In this paper, the influence of Si concentration on the electrical properties of Si-Te OTS materials is studied; the threshold voltage and leakage current remain basically unchanged with the decrease in electrode diameter. Meanwhile, the on-current density (J_on) increases significantly as the device is scaling down, and 25 MA/cm² on-current density is achieved in the 60-nm SiTe device. In addition, we also determine the state of the Si-Te OTS layer and preliminarily obtain the approximate band structure, from which we infer that the conduction mechanism conforms to the Poole-Frenkel (PF) model. Full article

(This article belongs to the Special Issue Amorphous and Nanocrystalline Semiconductors: Selected Papers from ICANS 29)

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8 pages, 2169 KiB

Open AccessCommunication

Determination of Hydrophobic Dispersive Surface Free Energy of Activated Carbon Fibers Measured by Inverse Gas Chromatographic Technique

by Seul-Yi Lee, Yeong-Hun Kim, Roop L. Mahajan and Soo-Jin Park

Nanomaterials 2023, 13(6), 1113; https://doi.org/10.3390/nano13061113 - 20 Mar 2023

Cited by 1 | Viewed by 1468

Abstract

Activated carbon fibers (ACFs) as one of the most important porous carbon materials are widely used in many applications that involve rapid adsorption and low-pressure loss, including air purification, water treatment, and electrochemical applications. For designing such fibers for the adsorption bed in [...] Read more.

Activated carbon fibers (ACFs) as one of the most important porous carbon materials are widely used in many applications that involve rapid adsorption and low-pressure loss, including air purification, water treatment, and electrochemical applications. For designing such fibers for the adsorption bed in gas and aqueous phases, in-depth comprehension of the surface components is crucial. However, achieving reliable values remains a major challenge due to the high adsorption affinity of ACFs. To overcome this problem, we propose a novel approach to determine London dispersive components (

γ_{S}^{L}

) of the surface free energy of ACFs by inverse gas chromatography (IGC) technique at an infinite dilution. Our data reveal the

γ_{S}^{L}

values at 298 K for bare carbon fibers (CFs) and the ACFs to be 97 and 260–285 mJ·m⁻², respectively, which lie in the regime of secondary bonding of physical adsorption. Our analysis indicates that these are impacted by micropores and defects on the carbon surfaces. Comparing the

γ_{S}^{L}

obtained by the traditional Gray’s method, our method is concluded as the most accurate and reliable value for the hydrophobic dispersive surface component of porous carbonaceous materials. As such, it could serve as a valuable tool in designing interface engineering in adsorption-related applications. Full article

(This article belongs to the Section Physical Chemistry at Nanoscale)

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13 pages, 11706 KiB

Open AccessArticle

Effect of Nano Nd₂O₃ on the Microstructure and High-Temperature Resistance of G@Ni Laser Alloying Coatings on Ti-6Al-4V Alloy

by Zifan Wang, Xiaoxi Meng, Zhihuan Zhao, Chuanzhong Chen and Huijun Yu

Nanomaterials 2023, 13(6), 1112; https://doi.org/10.3390/nano13061112 - 20 Mar 2023

Cited by 2 | Viewed by 1100

Abstract

Titanium and its alloys are widely used in high-end manufacturing fields. However, their low high-temperature oxidation resistance has limited their further application. Recently, laser alloying processing has attracted researchers to improve the surface properties of Ti, for which Ni coated graphite system is [...] Read more.

Titanium and its alloys are widely used in high-end manufacturing fields. However, their low high-temperature oxidation resistance has limited their further application. Recently, laser alloying processing has attracted researchers to improve the surface properties of Ti, for which Ni coated graphite system is an excellent prospect due to its outstanding properties and metallurgical bonding between coating and substrate. In this paper, nanoscaled rare earth oxide Nd₂O₃ addition was added to Ni coated graphite laser alloying materials to research its influence on the microstructure and high-temperature oxidation resistance of the coating. The results proved that nano-Nd₂O₃ has an outstanding effect on refining coating microstructures, thus the high-temperature oxidation resistance was improved. Furthermore, with the addition of 1. 5 wt.% nano-Nd₂O₃, more NiO formed in the oxide film, which effectively strengthened the protective effect of the film. After 100 h of 800 °C oxidation, the oxidation weight gain per unit area of the normal coating was 14.571 mg/cm², while that of the coating with nano-Nd₂O₃ addition was 6.244 mg/cm², further proving that the addition of nano-Nd₂O₃ substantially improved the high-temperature oxidation properties of the coating. Full article

(This article belongs to the Special Issue Processing, Surfaces and Interfaces of Nanomaterials)

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17 pages, 12126 KiB

Open AccessArticle

Preparation and Characterization of Nano-Fe₃O₄ and Its Application for C18-Functionalized Magnetic Nanomaterials Used as Chromatographic Packing Materials

by Wen-Xin Liu, Wei-Na Zhou, Shuang Song, Yong-Gang Zhao and Yin Lu

Nanomaterials 2023, 13(6), 1111; https://doi.org/10.3390/nano13061111 - 20 Mar 2023

Cited by 2 | Viewed by 1306

Abstract

A new type of magnetic nanomaterial with Fe₃O₄ as the core and organic polymer as the shell was synthesized by seed emulsion polymerization. This material not only overcomes the problem of insufficient mechanical strength of the organic polymer, it also [...] Read more.

A new type of magnetic nanomaterial with Fe₃O₄ as the core and organic polymer as the shell was synthesized by seed emulsion polymerization. This material not only overcomes the problem of insufficient mechanical strength of the organic polymer, it also solves the problem that Fe₃O₄ is prone to oxidation and agglomeration. In order to make the particle size of Fe₃O₄ meet the requirement of the seed, the solvothermal method was used to prepare Fe₃O₄. The effects of the reaction time, amount of solvent, pH value, and polyethylene glycol (PEG) on the particle size of Fe₃O₄ were investigated. In addition, in order to accelerate the reaction rate, the feasibility of preparing Fe₃O₄ by microwave was studied. The results showed that under the optimum conditions, the particle size of Fe₃O₄ could reach 400 nm and had good magnetic properties. After three stages of oleic acid coating, seed emulsion polymerization, and C18 modification, the obtained C18-functionalized magnetic nanomaterials were used for the preparation of the chromatographic column. Under optimal conditions, stepwise elution significantly shortened the elution time of sulfamethyldiazine, sulfamethazine, sulfamethoxypyridazine, and sulfamethoxazole while still achieving a baseline separation. Full article

(This article belongs to the Special Issue Advanced Nanomaterials for Adsorption Purposes)

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45 pages, 9073 KiB

Open AccessReview

Paper-Based Humidity Sensors as Promising Flexible Devices: State of the Art: Part 1. General Consideration

by Ghenadii Korotcenkov

Nanomaterials 2023, 13(6), 1110; https://doi.org/10.3390/nano13061110 - 20 Mar 2023

Cited by 5 | Viewed by 2761

Abstract

In the first part of the review article “General considerations” we give information about conventional flexible platforms and consider the advantages and disadvantages of paper when used in humidity sensors, both as a substrate and as a humidity-sensitive material. This consideration shows that [...] Read more.

In the first part of the review article “General considerations” we give information about conventional flexible platforms and consider the advantages and disadvantages of paper when used in humidity sensors, both as a substrate and as a humidity-sensitive material. This consideration shows that paper, especially nanopaper, is a very promising material for the development of low-cost flexible humidity sensors suitable for a wide range of applications. Various humidity-sensitive materials suitable for use in paper-based sensors are analyzed and the humidity-sensitive characteristics of paper and other humidity-sensitive materials are compared. Various configurations of humidity sensors that can be developed on the basis of paper are considered, and a description of the mechanisms of their operation is given. Next, we discuss the manufacturing features of paper-based humidity sensors. The main attention is paid to the consideration of such problems as patterning and electrode formation. It is shown that printing technologies are the most suitable for mass production of paper-based flexible humidity sensors. At the same time, these technologies are effective both in the formation of a humidity-sensitive layer and in the manufacture of electrodes. Full article

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

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11 pages, 2847 KiB

Open AccessEditor’s ChoiceArticle

Enhanced Electroluminescence from a Silicon Nanocrystal/Silicon Carbide Multilayer Light-Emitting Diode

by Teng Sun, Dongke Li, Jiaming Chen, Yuhao Wang, Junnan Han, Ting Zhu, Wei Li, Jun Xu and Kunji Chen

Nanomaterials 2023, 13(6), 1109; https://doi.org/10.3390/nano13061109 - 20 Mar 2023

Cited by 2 | Viewed by 1492

Abstract

Developing high-performance Si-based light-emitting devices is the key step to realizing all-Si-based optical telecommunication. Usually, silica (SiO₂) as the host matrix is used to passivate silicon nanocrystals, and a strong quantum confinement effect can be observed due to the large band [...] Read more.

Developing high-performance Si-based light-emitting devices is the key step to realizing all-Si-based optical telecommunication. Usually, silica (SiO₂) as the host matrix is used to passivate silicon nanocrystals, and a strong quantum confinement effect can be observed due to the large band offset between Si and SiO₂ (~8.9 eV). Here, for further development of device properties, we fabricate Si nanocrystals (NCs)/SiC multilayers and study the changes in photoelectric properties of the LEDs induced by P dopants. PL peaks centered at 500 nm, 650 nm and 800 nm can be detected, which are attributed to surface states between SiC and Si NCs, amorphous SiC and Si NCs, respectively. PL intensities are first enhanced and then decreased after introducing P dopants. It is believed that the enhancement is due to passivation of the Si dangling bonds at the surface of Si NCs, while the suppression is ascribed to enhanced Auger recombination and new defects induced by excessive P dopants. Un-doped and P-doped LEDs based on Si NCs/SiC multilayers are fabricated and the performance is enhanced greatly after doping. As fitted, emission peaks near 500 nm and 750 nm can be detected. The current density-voltage properties indicate that the carrier transport process is dominated by FN tunneling mechanisms, while the linear relationship between the integrated EL intensity and injection current illustrates that the EL mechanism is attributed to recombination of electron–hole pairs at Si NCs induced by bipolar injection. After doping, the integrated EL intensities are enhanced by about an order of magnitude, indicating that EQE is greatly improved. Full article

(This article belongs to the Special Issue Amorphous and Nanocrystalline Semiconductors: Selected Papers from ICANS 29)

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9 pages, 1697 KiB

Open AccessCommunication

Hydrophilic Surface Modification of Amorphous Hydrogenated Carbon Nanocomposite Films via Atmospheric Oxygen Plasma Treatment

by Algirdas Lazauskas, Mindaugas Andrulevičius, Brigita Abakevičienė, Dalius Jucius, Viktoras Grigaliūnas, Asta Guobienė and Šarūnas Meškinis

Nanomaterials 2023, 13(6), 1108; https://doi.org/10.3390/nano13061108 - 20 Mar 2023

Cited by 1 | Viewed by 1442

Abstract

Herein we investigated hydrophilic surface modification of SiO_x containing amorphous hydrogenated carbon nanocomposite films (DLC:SiO_x) via the use of atmospheric oxygen plasma treatment. The modified films exhibited effective hydrophilic properties with complete surface wetting. More detailed water droplet contact angle [...] Read more.

Herein we investigated hydrophilic surface modification of SiO_x containing amorphous hydrogenated carbon nanocomposite films (DLC:SiO_x) via the use of atmospheric oxygen plasma treatment. The modified films exhibited effective hydrophilic properties with complete surface wetting. More detailed water droplet contact angle (CA) measurements revealed that oxygen plasma treated DLC:SiO_x films maintained good wetting properties with CA of up to 28 ± 1° after 20 days of aging in ambient air at room temperature. This treatment process also increased surface root mean square roughness from 0.27 nm to 1.26 nm. Analysis of the surface chemical states suggested that the hydrophilic behavior of DLC:SiO_x treated with oxygen plasma is attributed to surface enrichment with C–O–C, SiO₂, and Si–Si chemical bonds as well as significant removal of hydrophobic Si–CH_x functional groups. The latter functional groups are prone to restoration and are mainly responsible for the increase in CA with aging. Possible applications of the modified DLC:SiO_x nanocomposite films could include biocompatible coatings for biomedical applications, antifogging coatings for optical components, and protective coatings to prevent against corrosion and wear. Full article

(This article belongs to the Special Issue Nanomaterials for Chemical Engineering (Volume II))

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