Nanomaterials

13 pages, 2790 KiB

Open AccessArticle

The Hydrogenation of Crotonaldehyde on PdCu Single Atom Alloy Catalysts

by Mohammed J. Islam, Marta Granollers Mesa, Amin Osatiashtiani, Martin J. Taylor, Mark A. Isaacs and Georgios Kyriakou

Nanomaterials 2023, 13(8), 1434; https://doi.org/10.3390/nano13081434 - 21 Apr 2023

Cited by 3 | Viewed by 2131

Abstract

Recyclable PdCu single atom alloys supported on Al₂O₃ were applied to the selective hydrogenation of crotonaldehyde to elucidate the minimum number of Pd atoms required to facilitate the sustainable transformation of an α,β-unsaturated carbonyl molecule. It was found that, by [...] Read more.

Recyclable PdCu single atom alloys supported on Al₂O₃ were applied to the selective hydrogenation of crotonaldehyde to elucidate the minimum number of Pd atoms required to facilitate the sustainable transformation of an α,β-unsaturated carbonyl molecule. It was found that, by diluting the Pd content of the alloy, the reaction activity of Cu nanoparticles can be accelerated, enabling more time for the cascade conversion of butanal to butanol. In addition, a significant increase in the conversion rate was observed, compared to bulk Cu/Al₂O₃ and Pd/Al₂O₃ catalysts when normalising for Cu and Pd content, respectively. The reaction selectivity over the single atom alloy catalysts was found to be primarily controlled by the Cu host surface, mainly leading to the formation of butanal but at a significantly higher rate than the monometallic Cu catalyst. Low quantities of crotyl alcohol were observed over all Cu-based catalysts but not for the Pd monometallic catalyst, suggesting that it may be a transient species converted immediately to butanol and or isomerized to butanal. These results demonstrate that fine-tuning the dilution of PdCu single atom alloy catalysts can leverage the activity and selectivity enhancement, and lead to cost-effective, sustainable, and atom-efficient alternatives to monometallic catalysts. Full article

(This article belongs to the Special Issue Nanocatalysis for Environmental Protection, Energy, and Green Chemistry)

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14 pages, 3478 KiB

Open AccessArticle

Single-Atom Anchored g-C₃N₄ Monolayer as Efficient Catalysts for Nitrogen Reduction Reaction

by Huadou Chai, Weiguang Chen, Zhen Feng, Yi Li, Mingyu Zhao, Jinlei Shi, Yanan Tang and Xianqi Dai

Nanomaterials 2023, 13(8), 1433; https://doi.org/10.3390/nano13081433 - 21 Apr 2023

Cited by 3 | Viewed by 1758

Abstract

Electrochemical N₂ reduction reaction (NRR) is a promising approach for NH₃ production under mild conditions. Herein, the catalytic performance of 3d transition metal (TM) atoms anchored on s-triazine-based g-C₃N₄ (TM@g-C₃N₄) in NRR is systematically [...] Read more.

Electrochemical N₂ reduction reaction (NRR) is a promising approach for NH₃ production under mild conditions. Herein, the catalytic performance of 3d transition metal (TM) atoms anchored on s-triazine-based g-C₃N₄ (TM@g-C₃N₄) in NRR is systematically investigated by density functional theory (DFT) calculations. Among these TM@g-C₃N₄ systems, the V@g-C₃N₄, Cr@g-C₃N₄, Mn@g-C₃N₄, Fe@g-C₃N₄, and Co@g-C₃N₄ monolayers have lower ΔG(*NNH) values, especially the V@g-C₃N₄ monolayer has the lowest limiting potential of −0.60 V and the corresponding limiting-potential steps are

*^{} N_{2} + H^{+} + e^{-} = *^{} N N H

for both alternating and distal mechanisms. For V@g-C₃N₄, the transferred charge and spin moment contributed by the anchored V atom activate N₂ molecule. The metal conductivity of V@g-C₃N₄ provides an effective guarantee for charge transfer between adsorbates and V atom during N₂ reduction reaction. After N₂ adsorption, the p-d orbital hybridization of *N₂ and V atoms can provide or receive electrons for the intermediate products, which makes the reduction process follow acceptance-donation mechanism. The results provide an important reference to design high efficiency single atom catalysts (SACs) for N₂ reduction. Full article

(This article belongs to the Topic Condensed Matter Physics and Catalysis)
(This article belongs to the Section Theory and Simulation of Nanostructures)

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13 pages, 4456 KiB

Open AccessArticle

Microwave-Assisted Metal-Organic Frameworks Derived Synthesis of Zn₂GeO₄ Nanowire Bundles for Lithium-Ion Batteries

by Chaofei Guo, Shuangqiang Chen, Junaid Aslam, Jiayi Li, Li-Ping Lv, Weiwei Sun, Weimin Cao and Yong Wang

Nanomaterials 2023, 13(8), 1432; https://doi.org/10.3390/nano13081432 - 21 Apr 2023

Cited by 1 | Viewed by 1530

Abstract

Germanium-based multi-metallic-oxide materials have advantages of low activation energy, tunable output voltage, and high theoretical capacity. However, they also exhibit unsatisfactory electronic conductivity, sluggish cation kinetics, and severe volume change, resulting in inferior long-cycle stability and rate performance in lithium-ion batteries (LIBs). To [...] Read more.

Germanium-based multi-metallic-oxide materials have advantages of low activation energy, tunable output voltage, and high theoretical capacity. However, they also exhibit unsatisfactory electronic conductivity, sluggish cation kinetics, and severe volume change, resulting in inferior long-cycle stability and rate performance in lithium-ion batteries (LIBs). To solve these problems, we synthesize metal-organic frameworks derived from rice-like Zn₂GeO₄ nanowire bundles as the anode of LIBs via a microwave-assisted hydrothermal method, minimizing the particle size and enlarging the cation’s transmission channels, as well as, enhancing the electronic conductivity of the materials. The obtained Zn₂GeO₄ anode exhibits superior electrochemical performance. A high initial charge capacity of 730 mAhg⁻¹ is obtained and maintained at 661 mAhg⁻¹ after 500 cycles at 100 mA g⁻¹ with a small capacity degradation ratio of ~0.02% for each cycle. Moreover, Zn₂GeO₄ exhibits a good rate performance, delivering a high capacity of 503 mA h g⁻¹ at 5000 mA g⁻¹. The good electrochemical performance of the rice-like Zn₂GeO₄ electrode can be attributed to its unique wire-bundle structure, the buffering effect of the bimetallic reaction at different potentials, good electrical conductivity, and fast kinetic rate. Full article

(This article belongs to the Special Issue The Eco-Friendly Nano-Candidate for Energy Storage and Conversion)

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14 pages, 3662 KiB

Open AccessArticle

PMMA/SWCNT Composites with Very Low Electrical Percolation Threshold by Direct Incorporation and Masterbatch Dilution and Characterization of Electrical and Thermoelectrical Properties

by Ezgi Uçar, Mustafa Dogu, Elcin Demirhan and Beate Krause

Nanomaterials 2023, 13(8), 1431; https://doi.org/10.3390/nano13081431 - 21 Apr 2023

Cited by 1 | Viewed by 1386

Abstract

In the present study, Poly(methyl methacrylate) (PMMA)/single-walled carbon nanotubes (SWCNT) composites were prepared by melt mixing to achieve suitable SWCNT dispersion and distribution and low electrical resistivity, whereby the SWCNT direct incorporation method was compared with masterbatch dilution. An electrical percolation threshold of [...] Read more.

In the present study, Poly(methyl methacrylate) (PMMA)/single-walled carbon nanotubes (SWCNT) composites were prepared by melt mixing to achieve suitable SWCNT dispersion and distribution and low electrical resistivity, whereby the SWCNT direct incorporation method was compared with masterbatch dilution. An electrical percolation threshold of 0.05–0.075 wt% was found, the lowest threshold value for melt-mixed PMMA/SWCNT composites reported so far. The influence of rotation speed and method of SWCNT incorporation into the PMMA matrix on the electrical properties and the SWCNT macro dispersion was investigated. It was found that increasing rotation speed improved macro dispersion and electrical conductivity. The results showed that electrically conductive composites with a low percolation threshold could be prepared by direct incorporation using high rotation speed. The masterbatch approach leads to higher resistivity values compared to the direct incorporation of SWCNTs. In addition, the thermal behavior and thermoelectric properties of PMMA/SWCNT composites were studied. The Seebeck coefficients vary from 35.8 µV/K to 53.4 µV/K for composites up to 5 wt% SWCNT. Full article

(This article belongs to the Special Issue 70th Year Anniversary of Carbon Nanotube Discovery—Focus on Real World Solutions)

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14 pages, 8329 KiB

Open AccessFeature PaperArticle

Multi-Technique Approach for Work Function Exploration of Sc₂O₃ Thin Films

by Alessio Mezzi, Eleonora Bolli, Saulius Kaciulis, Alessandro Bellucci, Barbara Paci, Amanda Generosi, Matteo Mastellone, Valerio Serpente and Daniele Maria Trucchi

Nanomaterials 2023, 13(8), 1430; https://doi.org/10.3390/nano13081430 - 21 Apr 2023

Cited by 3 | Viewed by 1263

Abstract

Thin films based on scandium oxide (Sc₂O₃) were deposited on silicon substrates to investigate the thickness effect on the reduction of work function. X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), energy dispersive X-ray reflectivity (EDXR), atomic force microscopy (AFM), [...] Read more.

Thin films based on scandium oxide (Sc₂O₃) were deposited on silicon substrates to investigate the thickness effect on the reduction of work function. X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), energy dispersive X-ray reflectivity (EDXR), atomic force microscopy (AFM), and ultraviolet photoelectron spectroscopy (UPS) measurements were performed on the films deposited by electron-beam evaporation with different nominal thicknesses (in the range of 2–50 nm) and in multi-layered mixed structures with barium fluoride (BaF₂) films. The obtained results indicate that non-continuous films are required to minimize the work function (down to 2.7 eV at room temperature), thanks to the formation of surface dipole effects between crystalline islands and substrates, even if the stoichiometry is far from the ideal one (Sc/O = 0.38). Finally, the presence of BaF₂ in multi-layered films is not beneficial for a further reduction in the work function. Full article

(This article belongs to the Special Issue Surface Analysis Techniques for the Study of Advanced Nanostructures)

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14 pages, 6006 KiB

Open AccessArticle

Nanoporous Amorphous Carbon with Exceptional Ultra-High Strength

by Daniel Castillo-Castro, Felipe Correa, Emiliano Aparicio, Nicolás Amigo, Alejandro Prada, Juan Figueroa, Rafael I. González, Eduardo Bringa and Felipe J. Valencia

Nanomaterials 2023, 13(8), 1429; https://doi.org/10.3390/nano13081429 - 21 Apr 2023

Cited by 1 | Viewed by 1625

Abstract

Nanoporous materials show a promising combination of mechanical properties in terms of their relative density; while there are numerous studies based on metallic nanoporous materials, here we focus on amorphous carbon with a bicontinuous nanoporous structure as an alternative to control the mechanical [...] Read more.

Nanoporous materials show a promising combination of mechanical properties in terms of their relative density; while there are numerous studies based on metallic nanoporous materials, here we focus on amorphous carbon with a bicontinuous nanoporous structure as an alternative to control the mechanical properties for the function of filament composition.Using atomistic simulations, we study the mechanical response of nanoporous amorphous carbon with 50% porosity, with sp

^{3}

content ranging from 10% to 50%. Our results show an unusually high strength between 10 and 20 GPa as a function of the

% s p^{3}

content. We present an analytical analysis derived from the Gibson–Ashby model for porous solids, and from the He and Thorpe theory for covalent solids to describe Young’s modulus and yield strength scaling laws extremely well, revealing also that the high strength is mainly due to the presence of sp

^{3}

bonding. Alternatively, we also find two distinct fracture modes: for low

% s p^{3}

samples, we observe a ductile-type behavior, while high

% s p^{3}

leads to brittle-type behavior due to high high shear strain clusters driving the carbon bond breaking that finally promotes the filament fracture. All in all, nanoporous amorphous carbon with bicontinuous structure is presented as a lightweight material with a tunable elasto-plastic response in terms of porosity and sp

^{3}

bonding, resulting in a material with a broad range of possible combinations of mechanical properties. Full article

(This article belongs to the Topic Advances in Computational Materials Sciences)

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15 pages, 4047 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Targeting of Tomato Bushy Stunt Virus with a Genetically Fused C-End Rule Peptide

by Luca Marchetti, Lorena Simon-Gracia, Chiara Lico, Mariateresa Mancuso, Selene Baschieri, Luca Santi and Tambet Teesalu

Nanomaterials 2023, 13(8), 1428; https://doi.org/10.3390/nano13081428 - 21 Apr 2023

Cited by 1 | Viewed by 1672

Abstract

Homing peptides are widely used to improve the delivery of drugs, imaging agents, and nanoparticles (NPs) to their target sites. Plant virus-based particles represent an emerging class of structurally diverse nanocarriers that are biocompatible, biodegradable, safe, and cost-effective. Similar to synthetic NPs, these [...] Read more.

Homing peptides are widely used to improve the delivery of drugs, imaging agents, and nanoparticles (NPs) to their target sites. Plant virus-based particles represent an emerging class of structurally diverse nanocarriers that are biocompatible, biodegradable, safe, and cost-effective. Similar to synthetic NPs, these particles can be loaded with imaging agents and/or drugs and functionalized with affinity ligands for targeted delivery. Here we report the development of a peptide-guided Tomato Bushy Stunt Virus (TBSV)-based nanocarrier platform for affinity targeting with the C-terminal C-end rule (CendR) peptide, RPARPAR (RPAR). Flow cytometry and confocal microscopy demonstrated that the TBSV-RPAR NPs bind specifically to and internalize in cells positive for the peptide receptor neuropilin-1 (NRP-1). TBSV-RPAR particles loaded with a widely used anticancer anthracycline, doxorubicin, showed selective cytotoxicity on NRP-1-expressing cells. Following systemic administration in mice, RPAR functionalization conferred TBSV particles the ability to accumulate in the lung tissue. Collectively, these studies show the feasibility of the CendR-targeted TBSV platform for the precision delivery of payloads. Full article

(This article belongs to the Special Issue Advances in Nanoscale Materials in Biomedicine)

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3 pages, 168 KiB

Open AccessEditorial

Editorial for Special Issue “Plasmon Assisted Near-Field Manipulation and Photocatalysis”

by Zhenglong Zhang

Nanomaterials 2023, 13(8), 1427; https://doi.org/10.3390/nano13081427 - 21 Apr 2023

Viewed by 912

Abstract

Accurately establishing the near field is crucial to enhancing optical manipulation and resolution, and is pivotal to the application of nanoparticles in the field of photocatalysis [...] Full article

(This article belongs to the Special Issue Plasmon Assisted Near-Field Manipulation and Photocatalysis)

16 pages, 8177 KiB

Open AccessReview

Graphene-Based ESD Protection for Future ICs

by Cheng Li, Zijin Pan, Weiquan Hao, Xunyu Li, Runyu Miao and Albert Wang

Nanomaterials 2023, 13(8), 1426; https://doi.org/10.3390/nano13081426 - 20 Apr 2023

Viewed by 1592

Abstract

On-chip electrostatic discharge (ESD) protection is required for all integrated circuits (ICs). Conventional on-chip ESD protection relies on in-Si PN junction-based device structures for ESD. However, such in-Si PN-based ESD protection solutions pose significant challenges related to ESD protection design overhead, including parasitic [...] Read more.

On-chip electrostatic discharge (ESD) protection is required for all integrated circuits (ICs). Conventional on-chip ESD protection relies on in-Si PN junction-based device structures for ESD. However, such in-Si PN-based ESD protection solutions pose significant challenges related to ESD protection design overhead, including parasitic capacitance, leakage current, and noises, as well as large chip area consumption and difficulty in IC layout floor planning. The design overhead effects of ESD protection devices are becoming unacceptable to modern ICs as IC technologies continuously advance, which is an emerging design-for-reliability challenge for advanced ICs. In this paper, we review the concept development of disruptive graphene-based on-chip ESD protection comprising a novel graphene nanoelectromechanical system (gNEMS) ESD switch and graphene ESD interconnects. This review discusses the simulation, design, and measurements of the gNEMS ESD protection structures and graphene ESD protection interconnects. The review aims to inspire non-traditional thinking for future on-chip ESD protection. Full article

(This article belongs to the Special Issue Abridging the CMOS Technology II)

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13 pages, 3349 KiB

Open AccessArticle

Fano Resonance in Near-Field Thermal Radiation of Two-Dimensional Van der Waals Heterostructures

by Huihai Wu, Xiaochuan Liu, Keyong Zhu and Yong Huang

Nanomaterials 2023, 13(8), 1425; https://doi.org/10.3390/nano13081425 - 20 Apr 2023

Cited by 1 | Viewed by 1386

Abstract

Two-dimensional (2D) materials and their vertically stacked heterostructures have attracted much attention due to their novel optical properties and strong light-matter interactions in the infrared. Here, we present a theoretical study of the near-field thermal radiation of 2D vdW heterostructures vertically stacked of [...] Read more.

Two-dimensional (2D) materials and their vertically stacked heterostructures have attracted much attention due to their novel optical properties and strong light-matter interactions in the infrared. Here, we present a theoretical study of the near-field thermal radiation of 2D vdW heterostructures vertically stacked of graphene and monolayer polar material (2D hBN as an example). An asymmetric Fano line shape is observed in its near-field thermal radiation spectrum, which is attributed to the interference between the narrowband discrete state (the phonon polaritons in 2D hBN) and a broadband continuum state (the plasmons in graphene), as verified by the coupled oscillator model. In addition, we show that 2D van der Waals heterostructures can achieve nearly the same high radiative heat flux as graphene but with markedly different spectral distributions, especially at high chemical potentials. By tuning the chemical potential of graphene, we can actively control the radiative heat flux of 2D van der Waals heterostructures and manipulate the radiative spectrum, such as the transition from Fano resonance to electromagnetic-induced transparency (EIT). Our results reveal the rich physics and demonstrate the potential of 2D vdW heterostructures for applications in nanoscale thermal management and energy conversion. Full article

(This article belongs to the Special Issue Next-Generation Infrared Optoelectronic Nanomaterials and Devices)

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46 pages, 14130 KiB

Open AccessReview

Recent Advancements in TiO₂ Nanostructures: Sustainable Synthesis and Gas Sensing

by Gayan W. C. Kumarage, Hadjer Hakkoum and Elisabetta Comini

Nanomaterials 2023, 13(8), 1424; https://doi.org/10.3390/nano13081424 - 20 Apr 2023

Cited by 9 | Viewed by 1651

Abstract

The search for sustainable technology-driven advancements in material synthesis is a new norm, which ensures a low impact on the environment, production cost, and workers’ health. In this context, non-toxic, non-hazardous, and low-cost materials and their synthesis methods are integrated to compete with [...] Read more.

The search for sustainable technology-driven advancements in material synthesis is a new norm, which ensures a low impact on the environment, production cost, and workers’ health. In this context, non-toxic, non-hazardous, and low-cost materials and their synthesis methods are integrated to compete with existing physical and chemical methods. From this perspective, titanium oxide (TiO₂) is one of the fascinating materials because of its non-toxicity, biocompatibility, and potential of growing by sustainable methods. Accordingly, TiO₂ is extensively used in gas-sensing devices. Yet, many TiO₂ nanostructures are still synthesized with a lack of mindfulness of environmental impact and sustainable methods, which results in a serious burden on practical commercialization. This review provides a general outline of the advantages and disadvantages of conventional and sustainable methods of TiO₂ preparation. Additionally, a detailed discussion on sustainable growth methods for green synthesis is included. Furthermore, gas-sensing applications and approaches to improve the key functionality of sensors, including response time, recovery time, repeatability, and stability, are discussed in detail in the latter parts of the review. At the end, a concluding discussion is included to provide guidelines for the selection of sustainable synthesis methods and techniques to improve the gas-sensing properties of TiO₂. Full article

(This article belongs to the Special Issue Recent Progress in TiO₂ Nanostructures)

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19 pages, 7095 KiB

Open AccessArticle

Optical Logic Gates Excited by a Gauss Vortex Interference Beam Based on Spatial Self-Phase Modulation in 2D MoS₂

by Xueyu Chen, Ge Ding, Linwei Tang, Haijian Zou, Chaofeng Wang, Shuqing Chen, Chenliang Su and Ying Li

Nanomaterials 2023, 13(8), 1423; https://doi.org/10.3390/nano13081423 - 20 Apr 2023

Cited by 2 | Viewed by 1339

Abstract

Vortex beams with optical orbital angular momentum have broad prospects in future high-speed and large-capacity optical communication. In this investigation of materials science, we found that low-dimensional materials have feasibility and reliability in the development of optical logic gates in all-optical signal processing [...] Read more.

Vortex beams with optical orbital angular momentum have broad prospects in future high-speed and large-capacity optical communication. In this investigation of materials science, we found that low-dimensional materials have feasibility and reliability in the development of optical logic gates in all-optical signal processing and computing technology. We found that spatial self-phase modulation patterns through the MoS₂ dispersions can be modulated by the initial intensity, phase, and topological charge of a Gauss vortex superposition interference beam. We utilized these three degrees of freedom as the input signals of the optical logic gate, and the intensity of a selected checkpoint on spatial self-phase modulation patterns as the output signal. By setting appropriate thresholds as logic codes 0 and 1, two sets of novel optical logic gates, including AND, OR, and NOT gates, were implemented. These optical logic gates are expected to have great potential in optical logic operations, all-optical networks, and all-optical signal processing. Full article

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

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10 pages, 2159 KiB

Open AccessArticle

High-Performance Thin-Film Transistors with ZnO:H/ZnO Double Active Layers Fabricated at Room Temperature

by Daoqin Wang, Zongjin Jiang, Linhan Li, Deliang Zhu, Chunfeng Wang, Shun Han, Ming Fang, Xinke Liu, Wenjun Liu, Peijiang Cao and Youming Lu

Nanomaterials 2023, 13(8), 1422; https://doi.org/10.3390/nano13081422 - 20 Apr 2023

Cited by 2 | Viewed by 1441

Abstract

H doping can enhance the performance of ZnO thin-film transistors (TFTs) to a certain extent, and the design of double active layers is an effective way to further improve a device’s performance. However, there are few studies on the combination of these two [...] Read more.

H doping can enhance the performance of ZnO thin-film transistors (TFTs) to a certain extent, and the design of double active layers is an effective way to further improve a device’s performance. However, there are few studies on the combination of these two strategies. We fabricated TFTs with ZnO:H (4 nm)/ZnO (20 nm) double active layers by magnetron sputtering at room temperature, and studied the effect of the hydrogen flow ratio on the devices’ performance. ZnO:H/ZnO-TFT has the best overall performance when H₂/(Ar + H₂) = 0.13% with a mobility of 12.10 cm²/Vs, an on/off current ratio of 2.32 × 10⁷, a subthreshold swing of 0.67 V/Dec, and a threshold voltage of 1.68 V, which is significantly better than the performance of single active layer ZnO:H-TFTs. This exhibits that the transport mechanism of carriers in double active layer devices is more complicated. On one hand, increasing the hydrogen flow ratio can more effectively suppress the oxygen-related defect states, thus reducing the carrier scattering and increasing the carrier concentration. On the other hand, the energy band analysis shows that electrons accumulate at the interface of the ZnO layer close to the ZnO:H layer, providing an additional path for carrier transport. Our research exhibits that the combination of a simple hydrogen doping process and double active layer construction can achieve the fabrication of high-performance ZnO-based TFTs, and that the whole room temperature process also provides important reference value for the subsequent development of flexible devices. Full article

(This article belongs to the Special Issue Abridging the CMOS Technology II)

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10 pages, 1344 KiB

Open AccessArticle

Effect of Plasmonic Ag Nanoparticles on Emission Properties of Planar GaN Nanowires

by Galia Pozina, Carl Hemmingsson, Natalia Abrikossova, Elizaveta I. Girshova, Erkki Lähderanta and Mikhail A. Kaliteevski

Nanomaterials 2023, 13(8), 1421; https://doi.org/10.3390/nano13081421 - 20 Apr 2023

Viewed by 1134

Abstract

The combination of plasmonic nanoparticles and semiconductor substrates changes the properties of hybrid structures that can be used for various applications in optoelectronics, photonics, and sensing. Structures formed by colloidal Ag nanoparticles (NPs) with a size of 60 nm and planar GaN nanowires [...] Read more.

The combination of plasmonic nanoparticles and semiconductor substrates changes the properties of hybrid structures that can be used for various applications in optoelectronics, photonics, and sensing. Structures formed by colloidal Ag nanoparticles (NPs) with a size of 60 nm and planar GaN nanowires (NWs) have been studied by optical spectroscopy. GaN NWs have been grown using selective-area metalorganic vapor phase epitaxy. A modification of the emission spectra of hybrid structures has been observed. In the vicinity of the Ag NPs, a new emission line appears at 3.36 eV. To explain the experimental results, a model considering the Fröhlich resonance approximation is suggested. The effective medium approach is used to describe the enhancement of emission features near the GaN band gap. Full article

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14 pages, 4931 KiB

Open AccessArticle

Strontium-Cobaltite-Based Perovskite (SrCoO₃) for Solar-Driven Interfacial Evaporation Systems for Clean Water Generation

by Miao He, Muneerah Alomar, Areej S. Alqarni, Naila Arshad, Muhammad Akbar, Muhammad Yousaf, Muhammad Sultan Irshad, Yuzheng Lu and Qiang Liu

Nanomaterials 2023, 13(8), 1420; https://doi.org/10.3390/nano13081420 - 20 Apr 2023

Cited by 2 | Viewed by 1490

Abstract

Solar-driven evaporation technology is often used in areas with limited access to clean water, as it provides a low-cost and sustainable method of water purification. Avoiding salt accumulation is still a substantial challenge for continuous desalination. Here, an efficient solar-driven water harvester that [...] Read more.

Solar-driven evaporation technology is often used in areas with limited access to clean water, as it provides a low-cost and sustainable method of water purification. Avoiding salt accumulation is still a substantial challenge for continuous desalination. Here, an efficient solar-driven water harvester that consists of strontium-cobaltite-based perovskite (SrCoO₃) anchored on nickel foam (SrCoO₃@NF) is reported. Synced waterways and thermal insulation are provided by a superhydrophilic polyurethane substrate combined with a photothermal layer. The structural photothermal properties of SrCoO₃ perovskite have been extensively investigated through state-of-the-art experimental investigations. Multiple incident rays are induced inside the diffuse surface, permitting wideband solar absorption (91%) and heat localization (42.01 °C @ 1 sun). Under 1 kW m⁻² solar intensity, the integrated SrCoO₃@NF solar evaporator has an outstanding evaporation rate (1.45 kg/m² h) and solar-to-vapor conversion efficiency (86.45% excluding heat losses). In addition, long-term evaporation measurements demonstrate small variance under sea water, illustrating the system’s working capacity for salt rejection (1.3 g NaCl/210 min), which is excellent for an efficient solar-driven evaporation application compared to other carbon-based solar evaporators. According to the findings of this research, this system offers significant potential for producing fresh water devoid of salt accumulation for use in industrial applications. Full article

(This article belongs to the Special Issue Nano-Enabled Materials for Clean Water and Energy Generation)

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22 pages, 7247 KiB

Open AccessArticle

UV-Excited Luminescence in Porous Organosilica Films with Various Organic Components

by Md Rasadujjaman, Jinming Zhang, Dmitry A. Spassky, Sergej Naumov, Alexey S. Vishnevskiy, Konstantin A. Vorotilov, Jiang Yan, Jing Zhang and Mikhail R. Baklanov

Nanomaterials 2023, 13(8), 1419; https://doi.org/10.3390/nano13081419 - 20 Apr 2023

Cited by 2 | Viewed by 1291

Abstract

UV-induced photoluminescence of organosilica films with ethylene and benzene bridging groups in their matrix and terminal methyl groups on the pore wall surface was studied to reveal optically active defects and understand their origin and nature. The careful selection of the film’s precursors [...] Read more.

UV-induced photoluminescence of organosilica films with ethylene and benzene bridging groups in their matrix and terminal methyl groups on the pore wall surface was studied to reveal optically active defects and understand their origin and nature. The careful selection of the film’s precursors and conditions of deposition and curing and analysis of chemical and structural properties led to the conclusion that luminescence sources are not associated with the presence of oxygen-deficient centers, as in the case of pure SiO₂. It is shown that the sources of luminescence are the carbon-containing components that are part of the low-k-matrix, as well as the carbon residues formed upon removal of the template and UV-induced destruction of organosilica samples. A good correlation between the energy of the photoluminescence peaks and the chemical composition is observed. This correlation is confirmed by the results obtained by the Density Functional theory. The photoluminescence intensity increases with porosity and internal surface area. The spectra become more complicated after annealing at 400 °C, although Fourier transform infrared spectroscopy does not show these changes. The appearance of additional bands is associated with the compaction of the low-k matrix and the segregation of template residues on the surface of the pore wall. Full article

(This article belongs to the Special Issue Advance in Photoactive Nanomaterials)

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21 pages, 7038 KiB

Open AccessReview

Advances in WO₃-Based Supercapacitors: State-of-the-Art Research and Future Perspectives

by Giacometta Mineo, Elena Bruno and Salvo Mirabella

Nanomaterials 2023, 13(8), 1418; https://doi.org/10.3390/nano13081418 - 20 Apr 2023

Cited by 10 | Viewed by 2340

Abstract

Electrochemical energy storage devices are one of the main protagonists in the ongoing technological advances in the energy field, whereby the development of efficient, sustainable, and durable storage systems aroused a great interest in the scientific community. Batteries, electrical double layer capacitors (EDLC), [...] Read more.

Electrochemical energy storage devices are one of the main protagonists in the ongoing technological advances in the energy field, whereby the development of efficient, sustainable, and durable storage systems aroused a great interest in the scientific community. Batteries, electrical double layer capacitors (EDLC), and pseudocapacitors are characterized in depth in the literature as the most powerful energy storage devices for practical applications. Pseudocapacitors bridge the gap between batteries and EDLCs, thus supplying both high energy and power densities, and transition metal oxide (TMO)-based nanostructures are used for their realization. Among them, WO₃ nanostructures inspired the scientific community, thanks to WO₃’s excellent electrochemical stability, low cost, and abundance in nature. This review analyzes the morphological and electrochemical properties of WO₃ nanostructures and their most used synthesis techniques. Moreover, a brief description of the electrochemical characterization methods of electrodes for energy storage, such as Cyclic Voltammetry (CV), Galvanostatic Charge–Discharge (GCD), and Electrochemical Impedance Spectroscopy (EIS) are reported, to better understand the recent advances in WO₃-based nanostructures, such as pore WO₃ nanostructures, WO₃/carbon nanocomposites, and metal-doped WO₃ nanostructure-based electrodes for pseudocapacitor applications. This analysis is reported in terms of specific capacitance calculated as a function of current density and scan rate. Then we move to the recent progress made for the design and fabrication of WO₃-based symmetric and asymmetric supercapacitors (SSCs and ASCs), thus studying a comparative Ragone plot of the state-of-the-art research. Full article

(This article belongs to the Special Issue Application of Nanomaterials in Solid-State Energy Storage Materials and Batteries)

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14 pages, 3679 KiB

Open AccessArticle

Hole-Transport Material Engineering in Highly Durable Carbon-Based Perovskite Photovoltaic Devices

by Reza Rahighi, Somayeh Gholipour, Mohammed A. Amin and Mohd Zahid Ansari

Nanomaterials 2023, 13(8), 1417; https://doi.org/10.3390/nano13081417 - 20 Apr 2023

Cited by 4 | Viewed by 1694

Abstract

Despite the fast-developing momentum of perovskite solar cells (PSCs) toward flexible roll-to-roll solar energy harvesting panels, their long-term stability remains to be the challenging obstacle in terms of moisture, light sensitivity, and thermal stress. Compositional engineering including less usage of volatile methylammonium bromide [...] Read more.

Despite the fast-developing momentum of perovskite solar cells (PSCs) toward flexible roll-to-roll solar energy harvesting panels, their long-term stability remains to be the challenging obstacle in terms of moisture, light sensitivity, and thermal stress. Compositional engineering including less usage of volatile methylammonium bromide (MABr) and incorporating more formamidinium iodide (FAI) promises more phase stability. In this work, an embedded carbon cloth in carbon paste is utilized as the back contact in PSCs (having optimized perovskite composition), resulting in a high power conversion efficiency (PCE) of 15.4%, and the as-fabricated devices retain 60% of the initial PCE after more than 180 h (at the experiment temperature of 85 °C and under 40% relative humidity). These results are from devices without any encapsulation or light soaking pre-treatments, whereas Au-based PSCs retain 45% of the initial PCE at the same conditions with rapid degradation. In addition, the long-term device stability results reveal that poly[bis(4–phenyl) (2,4,6–trimethylphenyl) amine] (PTAA) is a more stable polymeric hole-transport material (HTM) at the 85 °C thermal stress than the copper thiocyanate (CuSCN) inorganic HTM for carbon-based devices. These results pave the way toward modifying additive-free and polymeric HTM for scalable carbon-based PSCs. Full article

(This article belongs to the Special Issue Multifunctional Nanomaterials for Energy Storage Electrodes)

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11 pages, 14363 KiB

Open AccessArticle

Gentamicin Sulfate Grafted Magnetic GO Nanohybrids with Excellent Antibacterial Properties and Recyclability

by Xing Wu, Jingya Zhou, Zeng Liu and Wei Shao

Nanomaterials 2023, 13(8), 1416; https://doi.org/10.3390/nano13081416 - 20 Apr 2023

Viewed by 1083

Abstract

In this study, magnetic graphene oxide (MGO) nanohybrids were first prepared by loading Fe₃O₄ NPs onto graphene oxide (GO). Then, GS-MGO nanohybrids were prepared by grafting gentamicin sulfate (GS) onto MGO directly using a simple amidation reaction. The prepared GS-MGO [...] Read more.

In this study, magnetic graphene oxide (MGO) nanohybrids were first prepared by loading Fe₃O₄ NPs onto graphene oxide (GO). Then, GS-MGO nanohybrids were prepared by grafting gentamicin sulfate (GS) onto MGO directly using a simple amidation reaction. The prepared GS-MGO had the same magnetism as MGO. They exhibited excellent antibacterial ability against Gram-negative bacteria and Gram-positive bacteria. The GS-MGO had excellent antibacterial performance against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Listeria monocytogenes (L. monocytogenes). When the addition concentration of GS-MGO was 1.25 mg/mL, the calculated bacteriostatic ratios against E. coli and S. aureus achieved 89.8% and 100%, respectively. For L. monocytogenes, only 0.05 mg/mL of GS-MGO had an antibacterial ratio as high as 99%. In addition, the prepared GS-MGO nanohybrids also exhibited excellent non-leaching activity with good recycling antibacterial ability. After eight times antibacterial tests, GS-MGO nanohybrids still exhibited an excellent inhibition effect on E. coli, S. aureus, and L. monocytogenes. Therefore, as a non-leaching antibacterial agent, the fabricated GS-MGO nanohybrid had dramatic antibacterial properties and also showed great recycling ability. Thus, it displayed great potential in the design of novel recycling antibacterial agents with non-leaching activity. Full article

(This article belongs to the Special Issue Nanomaterials and Low-Dimensional Materials for Antibacterial Applications)

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15 pages, 6266 KiB

Open AccessArticle

The Enhancing Effect of Stable Oxygen Functional Groups on Porous-Carbon-Supported Pt Catalysts for Alkaline Hydrogen Evolution

by Xianyou Luo, Ping Yuan, Junhui Luo, Haoming Xiao, Junyi Li, Heng Zheng, Baodong Du, De Li and Yong Chen

Nanomaterials 2023, 13(8), 1415; https://doi.org/10.3390/nano13081415 - 20 Apr 2023

Cited by 5 | Viewed by 1255

Abstract

The oxygen functionalization of carbon materials has widely been employed to improve the catalytic performance of carbon-supported Pt (Pt/C) catalysts. Hydrochloric acid (HCl) has often been employed to clean carbons during the preparation of carbon materials. However, the effect of oxygen functionalization through [...] Read more.

The oxygen functionalization of carbon materials has widely been employed to improve the catalytic performance of carbon-supported Pt (Pt/C) catalysts. Hydrochloric acid (HCl) has often been employed to clean carbons during the preparation of carbon materials. However, the effect of oxygen functionalization through a HCl treatment of porous carbon (PC) supports on the performance of the alkaline hydrogen evolution reaction (HER) has rarely been investigated. Herein, the impact of HCl combined with the heat treatment of PC supports on the HER performance of Pt/C catalysts has been comprehensively investigated. The structural characterizations revealed similar structures of pristine and modified PC. Nevertheless, the HCl treatment resulted in abundant hydroxyl and carboxyl groups and the further heat treatment formed thermally stable carbonyl and ether groups. Among the catalysts, Pt loading on the HCl-treated PC followed by a heat treatment at 700 °C (Pt/PC-H-700) exhibited elevated HER activity with a lower overpotential of 50 mV at 10 mA cm⁻² when compared to the unmodified Pt/PC (89 mV). Pt/PC-H-700 also exhibited better durability than the Pt/PC. Overall, novel insights into the impact of the surface chemistry properties of porous carbon supports on the HER performance of Pt/C catalysts were provided, which were useful for highlighting the feasible improvement of HER performances by regulating the surface oxygen species of porous carbon supports. Full article

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12 pages, 5135 KiB

Open AccessArticle

Hierarchically Developed Ni(OH)₂@MgCo₂O₄ Nanosheet Composites for Boosting Supercapacitor Performance

by Hammad Mueen Arbi, Ganesh Koyyada, Yedluri Anil Kumar, Dasha Kumar Kulurumotlakatla, Jae Hong Kim, Md Moniruzzaman, Salem Alzahmi and Ihab M. Obaidat

Nanomaterials 2023, 13(8), 1414; https://doi.org/10.3390/nano13081414 - 19 Apr 2023

Cited by 5 | Viewed by 1515

Abstract

MgCo₂O₄ nanomaterial is thought to be a promising candidate for renewable energy storage and conversions. Nevertheless, the poor stability performances and small specific areas of transition-metal oxides remain a challenge for supercapacitor (SC) device applications. In this study, sheet-like Ni(OH) [...] Read more.

MgCo₂O₄ nanomaterial is thought to be a promising candidate for renewable energy storage and conversions. Nevertheless, the poor stability performances and small specific areas of transition-metal oxides remain a challenge for supercapacitor (SC) device applications. In this study, sheet-like Ni(OH)₂@MgCo₂O₄ composites were hierarchically developed on nickel foam (NF) using the facile hydrothermal process with calcination technology, under carbonization reactions. The combination of the carbon–amorphous layer and porous Ni(OH)₂ nanoparticles was anticipated to enhance the stability performances and energy kinetics. The Ni(OH)₂@MgCo₂O₄ nanosheet composite achieved a superior specific capacitance of 1287 F g⁻¹ at a current value of 1 A g⁻¹, which is higher than that of pure Ni(OH)₂ nanoparticles and MgCo₂O₄ nanoflake samples. At a current density of 5 A g⁻¹, the Ni(OH)₂@MgCo₂O₄ nanosheet composite delivered an outstanding cycling stability of 85.6%, which it retained over 3500 long cycles with an excellent rate of capacity of 74.5% at 20 A g⁻¹. These outcomes indicate that such a Ni(OH)₂@MgCo₂O₄ nanosheet composite is a good contender as a novel battery-type electrode material for high-performance SCs. Full article

(This article belongs to the Special Issue Nanomaterials for Supercapacitors)

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12 pages, 4020 KiB

Open AccessArticle

Controllable Synthesis of Sheet-Flower ZnO for Low Temperature NO₂ Sensor

by Mingjia Bai, Chaoyang Li, Xiaojun Zhao, Qingji Wang and Qinhe Pan

Nanomaterials 2023, 13(8), 1413; https://doi.org/10.3390/nano13081413 - 19 Apr 2023

Cited by 4 | Viewed by 1044

Abstract

ZnO is a wide band gap semiconductor metal oxide that not only has excellent electrical properties but also shows excellent gas-sensitive properties and is a promising material for the development of NO₂ sensors. However, the current ZnO-based gas sensors usually operate at [...] Read more.

ZnO is a wide band gap semiconductor metal oxide that not only has excellent electrical properties but also shows excellent gas-sensitive properties and is a promising material for the development of NO₂ sensors. However, the current ZnO-based gas sensors usually operate at high temperatures, which greatly increases the energy consumption of the sensors and is not conducive to practical applications. Therefore, there is a need to improve the gas sensitivity and practicality of ZnO-based gas sensors. In this study, three-dimensional sheet-flower ZnO was successfully synthesized at 60 °C by a simple water bath method and modulated by different malic acid concentrations. The phase formation, surface morphology, and elemental composition of the prepared samples were studied by various characterization techniques. The gas sensor based on sheet-flower ZnO has a high response value to NO₂ without any modification. The optimal operating temperature is 125 °C, and the response value to 1 ppm NO₂ is 125. At the same time, the sensor also has a lower detection limit (100 ppb), good selectivity, and good stability, showing excellent sensing performance. In the future, water bath-based methods are expected to prepare other metal oxide materials with unique structures. Full article

(This article belongs to the Special Issue Synthesis and Applications of Nanostructured Gas Sensors)

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16 pages, 6926 KiB

Open AccessArticle

The Photocatalytic Activity of CaTiO₃ Derived from the Microwave-Melting Heating Process of Blast Furnace Slag

by Jun Xie, Qing Ye, Jianghao Zhou, Yue Liao and Gongming Qian

Nanomaterials 2023, 13(8), 1412; https://doi.org/10.3390/nano13081412 - 19 Apr 2023

Cited by 3 | Viewed by 1029

Abstract

The extraction of titanium-bearing components in the form of CaTiO₃ is an efficient utilization of blast furnace slag. The photocatalytic performance of this obtained CaTiO₃ (MM-CaTiO₃) as a catalyst for methylene blue (MB) degradation was evaluated in this study. [...] Read more.

The extraction of titanium-bearing components in the form of CaTiO₃ is an efficient utilization of blast furnace slag. The photocatalytic performance of this obtained CaTiO₃ (MM-CaTiO₃) as a catalyst for methylene blue (MB) degradation was evaluated in this study. The analyses indicated that the MM-CaTiO₃ had a completed structure with a special length–diameter ratio. Furthermore, the oxygen vacancy was easier to generate on a MM-CaTiO₃(110) plane during the photocatalytic process, contributing to improving photocatalytic activity. Compared with traditional catalysts, MM-CaTiO₃ has a narrower optical band gap and visible-light responsive performance. The degradation experiments further confirmed that the photocatalytic degradation efficiency of pollutants by using MM-CaTiO₃ was 3.2 times that of pristine CaTiO₃ in optimized conditions. Combined with molecular simulation, the degradation mechanism clarified that acridine of MB molecular was stepwise destroyed by using MM-CaTiO₃ in short times, which is different from demethylation and methylenedioxy ring degradation by using TiO₂. This study provided a promising routine for using solid waste to obtain catalysts with excellent photocatalytic activity and was found to be in keeping with sustainable environmental development. Full article

(This article belongs to the Special Issue Photocatalytic Nanomaterials in Water Decontamination)

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14 pages, 2924 KiB

Open AccessArticle

Enhanced Electrochemical Performance of Metallic CoS-Based Supercapacitor by Cathodic Exfoliation

by Ye Tian, Yuxin Ma, Ruijin Sun, Weichao Zhang, Haikun Liu, Hao Liu and Libing Liao

Nanomaterials 2023, 13(8), 1411; https://doi.org/10.3390/nano13081411 - 19 Apr 2023

Cited by 6 | Viewed by 1549

Abstract

Two-dimensional nanomaterials hold great promise as electrode materials for the construction of excellent electrochemical energy storage and transformation apparatuses. In the study, metallic layered cobalt sulfide was, firstly, applied to the area of energy storage as a supercapacitor electrode. By a facile and [...] Read more.

Two-dimensional nanomaterials hold great promise as electrode materials for the construction of excellent electrochemical energy storage and transformation apparatuses. In the study, metallic layered cobalt sulfide was, firstly, applied to the area of energy storage as a supercapacitor electrode. By a facile and scalable method for cathodic electrochemical exfoliation, metallic layered cobalt sulfide bulk can be exfoliated into high-quality and few-layered nanosheets with size distributions in the micrometer scale range and thickness in the order of several nanometers. With a two-dimensional thin sheet structure of metallic cobalt sulfide nanosheets, not only was a larger active surface area created, but also, the insertion/extraction of ions in the procedure of charge and discharge were enhanced. The exfoliated cobalt sulfide was applied as a supercapacitor electrode with obvious improvement compared with the original sample, and the specific capacitance increased from 307 F∙g⁻¹ to 450 F∙g⁻¹ at the current density of 1 A∙g⁻¹. The capacitance retention rate of exfoliated cobalt sulfide enlarged to 84.7% from the original 81.9% of unexfoliated samples while the current density multiplied by 5 times. Moreover, a button-type asymmetric supercapacitor assembled using exfoliated cobalt sulfide as the positive electrode exhibits a maximum specific energy of 9.4 Wh∙kg⁻¹ at the specific power of 1520 W∙kg⁻¹. Full article

(This article belongs to the Special Issue Nanostructured Thin Films: From Synthesis to Application)

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10 pages, 1675 KiB

Open AccessArticle

DFT Study of Adsorption Behavior of Nitro Species on Carbon-Doped Boron Nitride Nanoribbons for Toxic Gas Sensing

by Francisco Villanueva-Mejia, Santiago José Guevara-Martínez, Manuel Arroyo-Albiter, José Juan Alvarado-Flores and Adalberto Zamudio-Ojeda

Nanomaterials 2023, 13(8), 1410; https://doi.org/10.3390/nano13081410 - 19 Apr 2023

Cited by 1 | Viewed by 998

Abstract

The modifications of the electronic properties on carbon-doped boron nitride nanoribbons (BNNRs) as a response to the adsorption of different nitro species were investigated in the framework of the density functional theory within the generalized gradient approximation. Calculations were performed using the SIESTA [...] Read more.

The modifications of the electronic properties on carbon-doped boron nitride nanoribbons (BNNRs) as a response to the adsorption of different nitro species were investigated in the framework of the density functional theory within the generalized gradient approximation. Calculations were performed using the SIESTA code. We found that the main response involved tuning the original magnetic behavior to a non-magnetic system when the molecule was chemisorbed on the carbon-doped BNNR. It was also revealed that some species could be dissociated through the adsorption process. Furthermore, the nitro species preferred to interact over nanosurfaces where dopants substituted the B sublattice of the carbon-doped BNNRs. Most importantly, the switch on the magnetic behavior offers the opportunity to apply these systems to fit novel technological applications. Full article

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

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15 pages, 368 KiB

Open AccessArticle

Exact Solutions for Non-Isothermal Flows of Second Grade Fluid between Parallel Plates

by Evgenii S. Baranovskii

Nanomaterials 2023, 13(8), 1409; https://doi.org/10.3390/nano13081409 - 19 Apr 2023

Cited by 5 | Viewed by 791

Abstract

In this paper, we obtain new exact solutions for the unidirectional non-isothermal flow of a second grade fluid in a plane channel with impermeable solid walls, taking into account the fluid energy dissipation (mechanical-to-thermal energy conversion) in the heat transfer equation. It is [...] Read more.

In this paper, we obtain new exact solutions for the unidirectional non-isothermal flow of a second grade fluid in a plane channel with impermeable solid walls, taking into account the fluid energy dissipation (mechanical-to-thermal energy conversion) in the heat transfer equation. It is assumed that the flow is time-independent and driven by the pressure gradient. On the channel walls, various boundary conditions are stated. Namely, we consider the no-slip conditions, the threshold slip conditions, which include Navier’s slip condition (free slip) as a limit case, as well as mixed boundary conditions, assuming that the upper and lower walls of the channel differ in their physical properties. The dependence of solutions on the boundary conditions is discussed in some detail. Moreover, we establish explicit relationships for the model parameters that guarantee the slip (or no-slip) regime on the boundaries. Full article

(This article belongs to the Special Issue Advances of Nanoscale Fluid Mechanics)

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18 pages, 8477 KiB

Open AccessArticle

Bifunctional Bicarbazole-Benzophenone-Based Twisted Donor–Acceptor–Donor Derivatives for Deep-Blue and Green OLEDs

by Prakalp Gautam, Shahnawaz, Iram Siddiqui, Dovydas Blazevicius, Gintare Krucaite, Daiva Tavgeniene, Jwo-Huei Jou and Saulius Grigalevicius

Nanomaterials 2023, 13(8), 1408; https://doi.org/10.3390/nano13081408 - 19 Apr 2023

Cited by 4 | Viewed by 1912

Abstract

Organic light-emitting diodes (OLEDs) have played a vital role in showing tremendous technological advancements for a better lifestyle, due to their display and lighting technologies in smartphones, tablets, television, and automotive industries. Undoubtedly, OLED is a mainstream technology and, inspired by its advancements, [...] Read more.

Organic light-emitting diodes (OLEDs) have played a vital role in showing tremendous technological advancements for a better lifestyle, due to their display and lighting technologies in smartphones, tablets, television, and automotive industries. Undoubtedly, OLED is a mainstream technology and, inspired by its advancements, we have designed and synthesized the bicarbazole-benzophenone-based twisted donor–acceptor–donor (D-A-D) derivatives, namely DB13, DB24, DB34, and DB43, as bi-functional materials. These materials possess high decomposition temperatures (>360 °C) and glass transition temperatures (~125 °C), a high photoluminescence quantum yield (>60%), wide bandgap (>3.2 eV), and short decay time. Owing to their properties, the materials were utilized as blue emitters as well as host materials for deep-blue and green OLEDs, respectively. In terms of the blue OLEDs, the emitter DB13-based device outperformed others by showing a maximum EQE of 4.0%, which is close to the theoretical limit of fluorescent materials for a deep-blue emission (CIE_y = 0.09). The same material also displayed a maximum power efficacy of 45 lm/W as a host material doped with a phosphorescent emitter Ir(ppy)₃. Furthermore, the materials were also utilized as hosts with a TADF green emitter (4CzIPN) and the device based on DB34 displayed a maximum EQE of 11%, which may be attributed to the high quantum yield (69%) of the host DB34. Therefore, the bi-functional materials that are easily synthesized, economical, and possess excellent characteristics are expected to be useful in various cost-effective and high-performance OLED applications, especially in displays. Full article

(This article belongs to the Topic Optical and Optoelectronic Properties of Materials and Their Applications)

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19 pages, 5077 KiB

Open AccessArticle

Corrosion Resistance of Nanostructured Cemented Carbides with Alternative FeNi and FeNiCo Binders

by Tamara Aleksandrov Fabijanić, Mateja Šnajdar, Marin Kurtela, Vedran Šimunović, Marijan Marciuš and Miho Klaić

Nanomaterials 2023, 13(8), 1407; https://doi.org/10.3390/nano13081407 - 19 Apr 2023

Cited by 3 | Viewed by 1074

Abstract

Nanostructured cemented carbides with Co binders have shown excellent mechanical properties in various applications. Nevertheless, their corrosion resistance has shown to be insufficient in different corrosive environments, leading to premature tool failure. In this study, WC-based cemented carbide samples with different binders were [...] Read more.

Nanostructured cemented carbides with Co binders have shown excellent mechanical properties in various applications. Nevertheless, their corrosion resistance has shown to be insufficient in different corrosive environments, leading to premature tool failure. In this study, WC-based cemented carbide samples with different binders were produced using 9 wt% of FeNi or FeNiCo with the addition of Cr₃C₂ and NbC as the grain growth inhibitors. The samples were investigated using electrochemical corrosion techniques: the open circuit potential E_corr, the linear polarization resistance (LPR), the Tafel extrapolation method, and the electrochemical impedance spectroscopy (EIS) at room temperature in the solution of 3.5% NaCl. Microstructure characterization, surface texture analysis, and instrumented indentation were conducted to investigate the influence of corrosion on the micro-mechanical properties and the surface characteristics of the samples before and after corrosion. The obtained results indicate a strong binder chemical composition’s effect on the consolidated materials’ corrosive behavior. Compared to the conventional WC-Co systems, a significantly improved corrosion resistance was observed for both alternative binder systems. The study shows that the samples with the FeNi binder are superior to those with the FeNiCo binder since they were almost unaffected when exposed to the acidic medium. Full article

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17 pages, 118618 KiB

Open AccessArticle

Bidimensional SnSe₂—Mesoporous Ordered Titania Heterostructures for Photocatalytically Activated Anti-Fingerprint Optically Transparent Layers

by Jessica De Santis, Valentina Paolucci, Luigi Stagi, Davide Carboni, Luca Malfatti, Carlo Cantalini and Plinio Innocenzi

Nanomaterials 2023, 13(8), 1406; https://doi.org/10.3390/nano13081406 - 19 Apr 2023

Cited by 3 | Viewed by 1566

Abstract

The design of functional coatings for touchscreens and haptic interfaces is of paramount importance for smartphones, tablets, and computers. Among the functional properties, the ability to suppress or eliminate fingerprints from specific surfaces is one of the most critical. We produced photoactivated anti-fingerprint [...] Read more.

The design of functional coatings for touchscreens and haptic interfaces is of paramount importance for smartphones, tablets, and computers. Among the functional properties, the ability to suppress or eliminate fingerprints from specific surfaces is one of the most critical. We produced photoactivated anti-fingerprint coatings by embedding 2D-SnSe₂ nanoflakes in ordered mesoporous titania thin films. The SnSe₂ nanostructures were produced by solvent-assisted sonication employing 1-Methyl-2-pyrrolidinone. The combination of SnSe₂ and nanocrystalline anatase titania enables the formation of photoactivated heterostructures with an enhanced ability to remove fingerprints from their surface. These results were achieved through careful design of the heterostructure and controlled processing of the films by liquid phase deposition. The self-assembly process is unaffected by the addition of SnSe₂, and the titania mesoporous films keep their three-dimensional pore organization. The coating layers show high optical transparency and a homogeneous distribution of SnSe₂ within the matrix. An evaluation of photocatalytic activity was performed by observing the degradation of stearic acid and Rhodamine B layers deposited on the photoactive films as a function of radiation exposure time. FTIR and UV-Vis spectroscopies were used for the photodegradation tests. Additionally, infrared imaging was employed to assess the anti-fingerprinting property. The photodegradation process, following pseudo-first-order kinetics, shows a tremendous improvement over bare mesoporous titania films. Furthermore, exposure of the films to sunlight and UV light completely removes the fingerprints, opening the route to several self-cleaning applications. Full article

(This article belongs to the Special Issue Advance in Photoactive Nanomaterials)

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19 pages, 8128 KiB

Open AccessArticle

Prediction Model and Mechanism for Drying Shrinkage of High-Strength Lightweight Concrete with Graphene Oxide

by Xiaojiang Hong, Jin Chai Lee, Jing Lin Ng, Muyideen Abdulkareem, Zeety Md Yusof, Qiansha Li and Qian He

Nanomaterials 2023, 13(8), 1405; https://doi.org/10.3390/nano13081405 - 19 Apr 2023

Viewed by 1225

Abstract

The excellent performance of graphene oxide (GO) in terms of mechanical properties and durability has stimulated its application potential in high-strength lightweight concrete (HSLWC). However, more attention needs to be paid to the long-term drying shrinkage of HSLWC. This work aims to investigate [...] Read more.

The excellent performance of graphene oxide (GO) in terms of mechanical properties and durability has stimulated its application potential in high-strength lightweight concrete (HSLWC). However, more attention needs to be paid to the long-term drying shrinkage of HSLWC. This work aims to investigate the compressive strength and drying shrinkage behavior of HSLWC incorporating low GO content (0.00–0.05%), focusing on the prediction and mechanism of drying shrinkage. Results indicate the following: (1) GO can acceptably reduce slump and significantly increase specific strength by 18.6%. (2) Drying shrinkage increased by 8.6% with the addition of GO. A modified ACI209 model with a GO content factor was demonstrated to have high accuracy based on the comparison of typical prediction models. (3) GO not only refines the pores but also forms flower-like crystals, which results in the increased drying shrinkage of HSLWC. These findings provide support for the prevention of cracking in HSLWC. Full article

(This article belongs to the Special Issue Smart Cementitious Materials for Sustainable Building Engineering)

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