Highly Conjugated Three-Dimensional van der Waals Heterostructures Based Nanocomposite Films for Ultrahigh-Responsivity TEA Gas Sensors at Room Temperature

2022 ◽  
Author(s):  
Shaofeng Shao ◽  
Chunyu Xie ◽  
Yuxuan Xia ◽  
Lei Zhang ◽  
Jun Zhang ◽  
...  
Keyword(s):  
Gas Sensors ◽  
Room Temperature ◽  
Gas Sensing ◽  
Van Der Waals ◽  
Three Dimensional ◽  
Nanocomposite Films ◽  
Covalent Organic Frameworks ◽  
Next Generation ◽  
Van Der Waals Heterostructures ◽  
Topological Structures

Covalent organic frameworks (COFs) have emerged as next-generation materials with predesigned π-electronic skeletons and highly ordered topological structures, which are promising for rapid gas sensing detection. COFs combined with carbon...

scholarly journals Three-dimensional platinum nanoparticle-based bridges for ammonia gas sensing

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nishchay A. Isaac ◽  
Johannes Reiprich ◽  
Leslie Schlag ◽  
Pedro H. O. Moreira ◽  
Mostafa Baloochi ◽  
...  
Keyword(s):  
Room Temperature ◽  
Gas Sensing ◽  
Response Times ◽  
High Surface ◽  
Three Dimensional ◽  
Performance Testing ◽  
Volume Ratio ◽  
Platinum Nanoparticle ◽  
Ammonia Gas ◽  
Lift Off

AbstractThis study demonstrates the fabrication of self-aligning three-dimensional (3D) platinum bridges for ammonia gas sensing using gas-phase electrodeposition. This deposition scheme can guide charged nanoparticles to predetermined locations on a surface with sub-micrometer resolution. A shutter-free deposition is possible, preventing the use of additional steps for lift-off and improving material yield. This method uses a spark discharge-based platinum nanoparticle source in combination with sequentially biased surface electrodes and charged photoresist patterns on a glass substrate. In this way, the parallel growth of multiple sensing nodes, in this case 3D self-aligning nanoparticle-based bridges, is accomplished. An array containing 360 locally grown bridges made out of 5 nm platinum nanoparticles is fabricated. The high surface-to-volume ratio of the 3D bridge morphology enables fast response and room temperature operated sensing capabilities. The bridges are preconditioned for ~ 24 h in nitrogen gas before being used for performance testing, ensuring drift-free sensor performance. In this study, platinum bridges are demonstrated to detect ammonia (NH3) with concentrations between 1400 and 100 ppm. The sensing mechanism, response times, cross-sensitivity, selectivity, and sensor stability are discussed. The device showed a sensor response of ~ 4% at 100 ppm NH3 with a 70% response time of 8 min at room temperature.

scholarly journals Silver Enhances Hematite Nanoparticles Based Ethanol Sensor Response and Selectivity at Room Temperature

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 440
Author(s):  
Daniel Garcia-Osorio ◽  
Pilar Hidalgo-Falla ◽  
Henrique E. M. Peres ◽  
Josue M. Gonçalves ◽  
Koiti Araki ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Gas Sensors ◽  
Room Temperature ◽  
Gas Sensing ◽  
Ethanol Vapor ◽  
Oxide Semiconductor ◽  
Charge Carrier Density ◽  
Ethanol Sensor ◽  
Volatile Organic

Gas sensors are fundamental for continuous online monitoring of volatile organic compounds. Gas sensors based on semiconductor materials have demonstrated to be highly competitive, but are generally made of expensive materials and operate at high temperatures, which are drawbacks of these technologies. Herein is described a novel ethanol sensor for room temperature (25 °C) measurements based on hematite (α‑Fe2O3)/silver nanoparticles. The AgNPs were shown to increase the oxide semiconductor charge carrier density, but especially to enhance the ethanol adsorption rate boosting the selectivity and sensitivity, thus allowing quantification of ethanol vapor in 2–35 mg L−1 range with an excellent linear relationship. In addition, the α-Fe2O3/Ag 3.0 wt% nanocomposite is cheap, and easy to make and process, imparting high perspectives for real applications in breath analyzers and/or sensors in food and beverage industries. This work contributes to the advance of gas sensing at ambient temperature as a competitive alternative for quantification of conventional volatile organic compounds.

scholarly journals Transformation Between 2D and 3D Covalent Organic Frameworks via Reversible [2+2] Cycloaddition

2020 ◽  
Author(s):  
Thaksen Jadhav ◽  
Yuan Fang ◽  
Cheng-Hao Liu ◽  
Afshin Dadvand ◽  
Ehsan Hamzehpoor ◽  
...  
Keyword(s):  
Band Structure ◽  
Absorption Edge ◽  
Room Temperature ◽  
Three Dimensional ◽  
Cross Linking ◽  
Two Dimensional ◽  
Covalent Organic Frameworks ◽  
Doping Behavior ◽  
2D Polymers ◽  
2D And 3D

We report the first transformation between crystalline vinylene-linked two-dimensional (2D) polymers and crystalline cyclobutane-linked three-dimensional (3D) polymers. Specifically, absorption-edge irradiation of the 2D poly(arylenevinylene) covalent organic frameworks (COFs) results in topological [2+2] cycloaddition cross-linking the π-stacked layers in 3D COFs. The reaction is reversible and heating to 200°C leads to a cycloreversion while retaining the COF crystallinity. The resulting difference in connectivity is manifested in the change of mechanical and electronic properties, including exfoliation, blue-shifted UV-Vis absorption, altered luminescence, modified band structure and different acid-doping behavior. The Li-impregnated 2D and 3D COFs show a significant ion conductivity of 1.8×10<sup>−4</sup> S/cm and 3.5×10<sup>−5</sup> S/cm, respectively. Even higher room temperature proton conductivity of 1.7×10<sup>-2</sup> S/cm and 2.2×10<sup>-3</sup> S/cm was found for H<sub>2</sub>SO<sub>4</sub>-treated 2D and 3D COFs, respectively.

scholarly journals Indirect excitons in van der Waals heterostructures at room temperature

2018 ◽  
Vol 9 (1) ◽  
Author(s):  
E. V. Calman ◽  
M. M. Fogler ◽  
L. V. Butov ◽  
S. Hu ◽  
A. Mishchenko ◽  
...  
Keyword(s):  
Room Temperature ◽  
Van Der Waals ◽  
Van Der Waals Heterostructures ◽  
Indirect Excitons

scholarly journals Tunable room-temperature spin galvanic and spin Hall effects in van der Waals heterostructures

2020 ◽  
Vol 19 (2) ◽  
pp. 170-175 ◽  
Author(s):  
L. Antonio Benítez ◽  
Williams Savero Torres ◽  
Juan F. Sierra ◽  
Matias Timmermans ◽  
Jose H. Garcia ◽  
...  
Keyword(s):  
Room Temperature ◽  
Van Der Waals ◽  
Van Der Waals Heterostructures ◽  
Hall Effects ◽  
Spin Hall Effects

Tunable Negative Differential Resistance in van der Waals Heterostructures at Room Temperature by Tailoring the Interface

ACS Nano ◽  
2019 ◽  
Vol 13 (7) ◽  
pp. 8193-8201 ◽  
Author(s):  
Sidi Fan ◽  
Quoc An Vu ◽  
Sanghyub Lee ◽  
Thanh Luan Phan ◽  
Gyeongtak Han ◽  
...  
Keyword(s):  
Negative Differential Resistance ◽  
Room Temperature ◽  
Van Der Waals ◽  
Differential Resistance ◽  
Van Der Waals Heterostructures

Emerging 2D hybrid nanomaterials: towards enhanced sensitive and selective conductometric gas sensors at room temperature

2020 ◽  
Vol 8 (38) ◽  
pp. 13108-13126
Author(s):  
Hanie Hashtroudi ◽  
Ian D. R. Mackinnon ◽  
Mahnaz Shafiei
Keyword(s):  
Gas Sensors ◽  
Room Temperature ◽  
Gas Sensing ◽  
Hybrid Nanomaterials ◽  
Sensing Performance

Gas sensing performance of conductometric devices based on 2D hybrid nanomaterials operating at room temperature.

TWO-DIMENSIONAL NANOSHEETS-ASSEMBLED FLOWER-LIKE Co3O4 MICROSPHERES AND THEIR GAS SENSING PERFORMANCES

NANO ◽  
2014 ◽  
Vol 09 (07) ◽  
pp. 1450071 ◽  
Author(s):  
HONGWEI CHE ◽  
AIFENG LIU ◽  
XIAOLIANG ZHANG ◽  
JUNXIAN HOU ◽  
JINGBO MU ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Gas Sensor ◽  
Gas Sensors ◽  
Gas Sensing ◽  
Solvothermal Method ◽  
Three Dimensional ◽  
Hexadecyltrimethylammonium Bromide ◽  
Two Dimensional ◽  
2D Nanosheets ◽  
Co3o4 Microspheres

In this paper, three-dimensional (3D) Co 3 O 4 flower-like microspheres have been successfully synthesized via a facile ethylene glycol (EG)-mediated solvothermal method followed by calcination. The as-prepared flower-like precursors microspheres are formed from the assembly of 2D nanosheets in the presence of hexadecyltrimethylammonium bromide (CTAB). The flower-like architectures of the prepared precursors could be tailored by changing the amount of CTAB. Furthermore, when evaluated as a gas sensor, the obtained Co 3 O 4 flower-like microspheres exhibit a good response and sensitivity toward ethanol gas, suggesting their promising potential for gas sensors application.

ZnO-Based Gas Sensors Prepared by EPD and Hydrothermal Growth

2015 ◽  
Vol 654 ◽  
pp. 94-98 ◽  
Author(s):  
Roman Yatskiv ◽  
María Verde ◽  
Jan Grym
Keyword(s):  
Gas Sensors ◽  
Room Temperature ◽  
Gas Sensing ◽  
Low Cost ◽  
Zno Nanorods ◽  
Zno Films ◽  
Nanorod Arrays ◽  
Zno Nanorod Arrays ◽  
Current Voltage ◽  
Gas Sensing Properties

Arrays of vertically well aligned ZnO nanorods (NRs) were prepared on nanostructured ZnO films using a low temperature hydrothermal method. We propose the use of the low cost, environmentally friendly electrophoretic deposition technique (EPD) as seeding procedure, which allows the obtaining of homogeneous, well oriented nanostructured ZnO thin films. ZnO nanorod arrays were covered with graphite in order to prepare graphite/ZnO NRs junctions. These nanostructured junctions showed promising current-voltage rectifying characteristics and gas sensing properties at room temperature.

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