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16 pages, 6674 KiB

Open AccessArticle

First-Principles Study of χ₃-Borophene as a Candidate for Gas Sensing and the Removal of Harmful Gases

by Jia-Xing Duan, Yu-Ping Tian, Chao-Bo Wang and Lian-Lian Zhang

Nanomaterials 2023, 13(14), 2117; https://doi.org/10.3390/nano13142117 - 20 Jul 2023

Cited by 2 | Viewed by 1080

Abstract

The potential application of borophene as a sensing material for gas-sensing devices is investigated in this work. We utilize density functional theory (DFT) to systematically study the adsorption mechanism and sensing performance of χ₃-borophene to search for high-sensitivity sensors for minor [...] Read more.

The potential application of borophene as a sensing material for gas-sensing devices is investigated in this work. We utilize density functional theory (DFT) to systematically study the adsorption mechanism and sensing performance of χ₃-borophene to search for high-sensitivity sensors for minor pollutant gases. We compare the results to those for two Pmmn borophenes. The first-principles calculations are used to analyze the sensing performance of the three different borophenes (2 Pmmn borophene, 8 Pmmn borophene, and χ₃-borophene) on five leading harmful gases (CO, NH₃, SO₂, H₂S, and NO₂). The adsorption configuration, adsorption energy, and electronic properties of χ₃-borophene are investigated. Our results indicate that the mechanism of adsorption on χ₃-borophene is chemisorption for NO₂ and physisorption for SO₂ and H₂S. The mode of adsorption of CO and NH₃ on χ₃-borophene can be both physisorption and chemisorption, depending on the initially selected sites. Analyses of the charge transfer and density of states show that χ₃-borophene is selective toward the adsorption of harmful gases and that N and O atoms form covalent bonds when chemisorbed on the surface of χ₃-borophene. An interesting phenomenon is that when 8 Pmmn borophene adsorbs SO₂, the gas molecules are dismembered and strongly adsorb on the surface of 8 Pmmn borophene, which provides a way of generating O₂ while adsorbing harmful substances. Overall, the results of this work demonstrate the potential applications of borophene as a sensing material for harmful gas sensing or removal. Full article

(This article belongs to the Special Issue 2D Materials for Advanced Sensors: Fabrication and Applications)

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13 pages, 4171 KiB

Open AccessArticle

Broadband Optical Properties of Bi₂Se₃

by Georgy A. Ermolaev, Ivan S. Vyslanko, Andrey P. Tselin, Marwa A. El-Sayed, Mikhail K. Tatmyshevskiy, Aleksandr S. Slavich, Dmitry I. Yakubovsky, Mikhail S. Mironov, Arslan B. Mazitov, Amir Eghbali, Daria A. Panova, Roman I. Romanov, Andrey M. Markeev, Ivan A. Kruglov, Sergey M. Novikov, Andrey A. Vyshnevyy, Aleksey V. Arsenin and Valentyn S. Volkov

Nanomaterials 2023, 13(9), 1460; https://doi.org/10.3390/nano13091460 - 25 Apr 2023

Cited by 4 | Viewed by 1713

Abstract

Materials with high optical constants are of paramount importance for efficient light manipulation in nanophotonics applications. Recent advances in materials science have revealed that van der Waals (vdW) materials have large optical responses owing to strong in-plane covalent bonding and weak out-of-plane vdW [...] Read more.

Materials with high optical constants are of paramount importance for efficient light manipulation in nanophotonics applications. Recent advances in materials science have revealed that van der Waals (vdW) materials have large optical responses owing to strong in-plane covalent bonding and weak out-of-plane vdW interactions. However, the optical constants of vdW materials depend on numerous factors, e.g., synthesis and transfer method. Here, we demonstrate that in a broad spectral range (290–3300 nm) the refractive index n and the extinction coefficient k of Bi₂Se₃ are almost independent of synthesis technology, with only a

~

10% difference in n and k between synthesis approaches, unlike other vdW materials, such as MoS₂, which has a

~

60% difference between synthesis approaches. As a practical demonstration, we showed, using the examples of biosensors and therapeutic nanoparticles, that this slight difference in optical constants results in reproducible efficiency in Bi₂Se₃-based photonic devices. Full article

(This article belongs to the Special Issue 2D Materials for Advanced Sensors: Fabrication and Applications)

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7 pages, 1727 KiB

Open AccessArticle

Direct CVD Growth of Transferable 3D Graphene for Sensitive and Flexible SERS Sensor

by Su Han Kim, Shiru Jiang and Sang-Shin Lee

Nanomaterials 2023, 13(6), 1029; https://doi.org/10.3390/nano13061029 - 13 Mar 2023

Cited by 1 | Viewed by 1690

Abstract

Three-dimensional (3D) graphene (Gr) has been successfully grown on a patterned sapphire substrate (PSS) with very low mismatch between Gr and the sapphire nanostructure through metal-catalyst-assisted chemical vapor deposition (CVD). However, the transfer of the 3D Gr film without compromising the structural integrity [...] Read more.

Three-dimensional (3D) graphene (Gr) has been successfully grown on a patterned sapphire substrate (PSS) with very low mismatch between Gr and the sapphire nanostructure through metal-catalyst-assisted chemical vapor deposition (CVD). However, the transfer of the 3D Gr film without compromising the structural integrity of Gr is challenging because of the low etching rate of PSS. For easy and high-quality transfer of 3D Gr, we propose to coat a transfer-support layer (TSL) on PSS before direct CVD growth of 3D Gr. The TSL is directly deposited on PSS by atomic layer deposition without causing any structural changes in the substrate, as verified through atomic force microscopy (AFM). Few-layer 3D Gr is conformally produced along the surface of the TSL/PSS and successfully transferred onto a flexible substrate through wet-etching transfer, as confirmed by scanning electron microscopy, AFM, and Raman spectroscopy studies. We also present the fabrication of a sensitive and flexible surface-enhanced Raman scattering sensor based on 3D Gr on PMMA with high detection performance for low concentrations of R6G (10⁻⁹ M). The proposed transfer method with TSL is expected to broaden the use of 3D graphene in next-generation device applications. Full article

(This article belongs to the Special Issue 2D Materials for Advanced Sensors: Fabrication and Applications)

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13 pages, 2947 KiB

Open AccessArticle

Design and Simulation of a Ratiometric SPR Sensor Based on a 2D van der Waals Heterojunction for Refractive Index Measurement

by Jun Zhou, Xiantong Yu, Lianzhen Zhang, Xuejing Liu, Youjun Zeng and Xuedian Zhang

Nanomaterials 2023, 13(3), 515; https://doi.org/10.3390/nano13030515 - 27 Jan 2023

Cited by 2 | Viewed by 1114

Abstract

Surface plasmon resonance (SPR) sensors have been widely applied in many fields because of their advantages of working in real time and high sensitivity. However, because the spectrum of an SPR sensor is easily affected by the smoothness of the metal surface, this [...] Read more.

Surface plasmon resonance (SPR) sensors have been widely applied in many fields because of their advantages of working in real time and high sensitivity. However, because the spectrum of an SPR sensor is easily affected by the smoothness of the metal surface, this type of sensor has obvious disadvantages in the application of quantitative detection. We designed an SPR refractive index sensor for molecular detection that has the advantage of quantifiability. A ratio spectral quantitative analysis method was established based on the two coherent dips of the SPR spectrum formed by the strong coupling effect between the surface plasmon polaritons and the excitons of the J-aggregate molecule 5,6-dichloro-2–[3–[5,6-dichloro-1-ethyl-3–(4-sulfobutyl)–2-benzimidazoline subunit] propenyl]–3-ethyl-1–(4-sulfobutyl) benzimidazole hydroxide inner salt (TDBC). The introduced MoS₂/graphene van der Waals heterojunction produced an effective charge transfer to the Ag film, resulting in significant electric field enhancement at the sensing interface and further improving the detection sensitivity of the sensor. The simulation results showed that for 43 nm Ag film, for example, the ratiometric SPR sensor with the Ag film structure can obtain 16.12 RIU⁻¹ sensing sensitivity, applied to the detection of gas molecules, while the SPR sensor with single-layer graphene and three layers of MoS₂ heterostructures can obtain 50.68 RIU⁻¹ sensing sensitivity. The addition of van der Waals heterostructures can significantly improve sensing performance by 215%. Full article

(This article belongs to the Special Issue 2D Materials for Advanced Sensors: Fabrication and Applications)

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11 pages, 2416 KiB

Open AccessEditor’s ChoiceArticle

Pixelated Micropolarizer Array Based on Carbon Nanotube Films

by Hui Zhang, Yanji Yi, Yibin Wang, Huwang Hou, Ting Meng, Peng Zhang and Yang Zhao

Nanomaterials 2023, 13(3), 391; https://doi.org/10.3390/nano13030391 - 18 Jan 2023

Viewed by 1086

Abstract

A micropolarizer array (MPA) that can be integrated into a scientific camera is proposed as a real-time polarimeter that is capable of extracting the polarization parameters. The MPA is based on highly aligned carbon nanotube (CNT) films inspired by their typical anisotropy and [...] Read more.

A micropolarizer array (MPA) that can be integrated into a scientific camera is proposed as a real-time polarimeter that is capable of extracting the polarization parameters. The MPA is based on highly aligned carbon nanotube (CNT) films inspired by their typical anisotropy and selectivity for light propagation over a wide spectral range. The MPA contains a dual-tier CNT pixel plane with 0° and 45° orientations. The thickness of the dual-tier structure of the CNT-based MPA is limited to less than 2 μm with a pixel size of 7.45 μm × 7.45 μm. The degree of polarization of the CNT-MPA reached 93% at a 632 nm wavelength. The specific designs in structure and semiconductor fabrication procedures are described. Compared with customary MPAs, CNT-based MPA holds great potential in decreasing the cross-talk risk associated with lower film thickness and can be extended to a wide spectral range. Full article

(This article belongs to the Special Issue 2D Materials for Advanced Sensors: Fabrication and Applications)

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12 pages, 5293 KiB

Open AccessEditor’s ChoiceArticle

Green Extraction of Graphene from Natural Mineral Shungite

by Anastasia Novikova and Alina Karabchevsky

Nanomaterials 2022, 12(24), 4356; https://doi.org/10.3390/nano12244356 - 7 Dec 2022

Cited by 4 | Viewed by 1623

Abstract

Conventional fabrication methods to produce graphene are cumbersome, expensive, and not ecologically friendly. This is due to the fact that the processing of a large volume of raw materials requires large amounts of acids and alkalis which, in turn, require special disposal. Therefore, [...] Read more.

Conventional fabrication methods to produce graphene are cumbersome, expensive, and not ecologically friendly. This is due to the fact that the processing of a large volume of raw materials requires large amounts of acids and alkalis which, in turn, require special disposal. Therefore, it is necessary to develop new technologies or to refine existing ones for the production of graphene—and to create new, ecologically-safe and effective methods. Here, we utilized physical sonication to extract graphene films from natural mineral shungite rock. From our study of the structure of shungite by Raman spectrometry and X-ray phase analysis, we found that shungite is characterized by graphite-like mineral structures. Transmission electron microscopy images obtained from the processed material revealed graphene films—with surfaces as small as 200 nanometers long and several layers wide. Our green method of fabicating graphene can be widely used in a variety of fields, from electro-optics to ecology, to list a few. Full article

(This article belongs to the Special Issue 2D Materials for Advanced Sensors: Fabrication and Applications)

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10 pages, 4099 KiB

Open AccessArticle

Green-Graphene Protective Overlayer on Optical Microfibers: Prolongs the Device Lifetime

by Anastasia Novikova, Aviad Katiyi, Aviran Halstuch and Alina Karabchevsky

Nanomaterials 2022, 12(17), 2915; https://doi.org/10.3390/nano12172915 - 24 Aug 2022

Cited by 4 | Viewed by 1075

Abstract

Optical microfibers find new applications in various fields of industry, which in turn require wear resistance, environmental friendliness and ease of use. However, optical microfibers are fragile. Here we report a new method to prolong the microfiber lifetime by modifying its surface with [...] Read more.

Optical microfibers find new applications in various fields of industry, which in turn require wear resistance, environmental friendliness and ease of use. However, optical microfibers are fragile. Here we report a new method to prolong the microfiber lifetime by modifying its surface with green-extracted graphene overlayers. Graphene films were obtained by dispergation of shungite mineral samples in an aqueous medium. For this, we tapered optical fibers and sculptured them with graphene films mixed with gold nanoparticles. We observed that due to the surface modification the lifetime and survivability of the microfiber increased 5 times, as compared to the bare microfiber. The embedded gold nanoparticles can also be utilized for enhanced sensitivity and other applications. Full article

(This article belongs to the Special Issue 2D Materials for Advanced Sensors: Fabrication and Applications)

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Review

Jump to: Research

32 pages, 11348 KiB

Open AccessReview

Current Trends in Nanomaterials for Metal Oxide-Based Conductometric Gas Sensors: Advantages and Limitations—Part 2: Porous 2D Nanomaterials

by Ghenadii Korotcenkov and Valeri P. Tolstoy

Nanomaterials 2023, 13(2), 237; https://doi.org/10.3390/nano13020237 - 5 Jan 2023

Cited by 8 | Viewed by 1929

Abstract

This article discusses the features of the synthesis and application of porous two-dimensional nanomaterials in developing conductometric gas sensors based on metal oxides. It is concluded that using porous 2D nanomaterials and 3D structures based on them is a promising approach to improving [...] Read more.

This article discusses the features of the synthesis and application of porous two-dimensional nanomaterials in developing conductometric gas sensors based on metal oxides. It is concluded that using porous 2D nanomaterials and 3D structures based on them is a promising approach to improving the parameters of gas sensors, such as sensitivity and the rate of response. The limitations that may arise when using 2D structures in gas sensors intended for the sensor market are considered. Full article

(This article belongs to the Special Issue 2D Materials for Advanced Sensors: Fabrication and Applications)

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