scholarly journals Facile Fabrication of Hybrid Carbon Nanotube Sensors by Laser Direct Transfer

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2604
Author(s):  
Anca F. Bonciu ◽  
Mihaela Filipescu ◽  
Stefan I. Voicu ◽  
Thomas Lippert ◽  
Alexandra Palla-Papavlu
Keyword(s):  
Room Temperature ◽  
Limit Of Detection ◽  
Theoretical Limit ◽  
Accurate Identification ◽  
Forward Transfer ◽  
Facile Fabrication ◽  
Multiple Cycles ◽  
Tin Oxide Nanoparticles ◽  
Walled Carbon Nanotubes ◽  
Hybrid Carbon

Ammonia is one of the most frequently produced chemicals in the world, and thus, reliable measurements of different NH3 concentrations are critical for a variety of industries, among which are the agricultural and healthcare sectors. The currently available technologies for the detection of NH3 provide accurate identification; however, they are limited by size, portability, and fabrication cost. Therefore, in this work, we report the laser-induced forward transfer (LIFT) of single-walled carbon nanotubes (SWCNTs) decorated with tin oxide nanoparticles (SnO2 NPs), which act as sensitive materials in chemiresistive NH3 sensors. We demonstrate that the LIFT-fabricated sensors can detect NH3 at room temperature and have a response time of 13 s (for 25 ppm NH3). In addition, the laser-fabricated sensors are fully reversible when exposed to multiple cycles of NH3 and have an excellent theoretical limit of detection of 24 ppt.

scholarly journals Facile Fabrication of Hybrid Carbon Nanotube Sensors by Laser Direct Transfer

2021 ◽  
Author(s):  
Anca Bonciu ◽  
Mihaela Filipescu ◽  
Stefan Voicu ◽  
Thomas Lippert ◽  
Alexandra Palla-Papavlu
Keyword(s):  
Room Temperature ◽  
Hybrid Nanocomposites ◽  
Great Promise ◽  
Direct Transfer ◽  
Future Developments ◽  
Facile Fabrication ◽  
Tin Oxide Nanoparticles ◽  
Walled Carbon Nanotubes ◽  
Gas Response ◽  
Hybrid Carbon

Abstract This paper describes a rapid, solvent-free laser based procedure for the fabrication of reproducible sensitive sensors based on hybrid nanocomposites, i.e. single walled carbon nanotubes (SWCNTs) decorated with tin oxide nanoparticles (SnO2 NP) that overcomes challenges associated with solvent-assisted chemical functionalization and integration of these materials into devices. The gas response of the LIFT-ed SWCNT: SnO2 sensors has been evaluated at room temperature and an enhanced 2 fold response to ammonia as compared to the SWCNT sensors is demonstrated. Spontaneous and full recovery of the hybrid nanocomposite signal after exposure to NH3 is achieved without any post treatment. The theoretical detection limit of the LIFT-ed SWCNT: SnO2 sensors at room temperature is calculated to be 0.59 ppb. These results indicate that LIFT is an excellent technique which shows great promise towards advancing future developments in the field of chemical sensors.

scholarly journals Selective and self-validating breath-level detection of hydrogen sulfide in humid air by gold nanoparticle-functionalized nanotube arrays

Nano Research ◽  
2021 ◽  
Author(s):  
Luis Antonio Panes-Ruiz ◽  
Leif Riemenschneider ◽  
Mohamad Moner Al Chawa ◽  
Markus Löffler ◽  
Bernd Rellinghaus ◽  
...  
Keyword(s):  
Hydrogen Sulfide ◽  
Room Temperature ◽  
Sensor Array ◽  
High Selectivity ◽  
Electrochemical Sensors ◽  
Gas Sensing ◽  
Limit Of Detection ◽  
Electrical Characteristics ◽  
Sensor Fabrication ◽  
Walled Carbon Nanotubes

AbstractWe demonstrate the selective detection of hydrogen sulfide at breath concentration levels under humid airflow, using a self-validating 64-channel sensor array based on semiconducting single-walled carbon nanotubes (sc-SWCNTs). The reproducible sensor fabrication process is based on a multiplexed and controlled dielectrophoretic deposition of sc-SWCNTs. The sensing area is functionalized with gold nanoparticles to address the detection at room temperature by exploiting the affinity between gold and sulfur atoms of the gas. Sensing devices functionalized with an optimized distribution of nanoparticles show a sensitivity of 0.122%/part per billion (ppb) and a calculated limit of detection (LOD) of 3 ppb. Beyond the self-validation, our sensors show increased stability and higher response levels compared to some commercially available electrochemical sensors. The cross-sensitivity to breath gases NH3 and NO is addressed demonstrating the high selectivity to H2S. Finally, mathematical models of sensors’ electrical characteristics and sensing responses are developed to enhance the differentiation capabilities of the platform to be used in breath analysis applications.

scholarly journals A Facile and Efficient Bromination of Multi-Walled Carbon Nanotubes

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3161
Author(s):  
Sandra Zarska ◽  
Damian Kulawik ◽  
Volodymyr Pavlyuk ◽  
Piotr Tomasik ◽  
Alicja Bachmatiuk ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Room Temperature ◽  
Covalent Attachment ◽  
Closed Vessel ◽  
Dangling Bonds ◽  
Magnetic Stirrer ◽  
Defect Sites ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Covalently Bound

The bromination of multi-walled carbon nanotubes (MWCNT) was performed with vapor bromine in a closed vessel, and they were subjected to intensive stirring with a magnetic stirrer for up to 14 days. The efficiency of bromination was compared depending upon duration. The structure and surface of the crude and purified products were characterized by detailed physicochemical analyses, such as SEM/EDS, TEM, XRD, TGA, Raman, and XPS spectroscopies. The studies confirmed the presence of bromine covalently bound with nanotubes as well as the formation of inclusion MWCNT–Br2 complexes. It was confirmed that Br2 molecules are absorbed on the surface of nanotubes (forming the CNT-Br2 complex), while they can dissociate close to dangling bonds at CNT defect sites with the formation of covalent C−Br bonds. Thus, any covalent attachment of bromine to the graphitic surface achieved around room temperature is likely related to the defects in the MWCNTs. The best results, i.e., the highest amount of attached Br2, were obtained for brominated nanotubes brominated for 10 days, with the content of covalently bound bromine being 0.68 at% (by XPS).

scholarly journals Electrochemical Detection of Endosulfan Using an AONP-PANI-SWCNT Modified Glassy Carbon Electrode

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 723
Author(s):  
Kgotla K. Masibi ◽  
Omolola E. Fayemi ◽  
Abolanle S. Adekunle ◽  
Amal M. Al-Mohaimeed ◽  
Asmaa M. Fahim ◽  
...  
Keyword(s):  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Limit Of Detection ◽  
Modified Electrodes ◽  
Antimony Oxide ◽  
Current Response ◽  
Carbon Electrode ◽  
Trace Detection ◽  
Limit Of Quantification ◽  
Walled Carbon Nanotubes

This report narrates the successful application of a fabricated novel sensor for the trace detection of endosulfan (EDS). The sensor was made by modifying a glassy-carbon electrode (GCE) with polyaniline (PANI), chemically synthesized antimony oxide nanoparticles (AONPs), acid-functionalized, single-walled carbon nanotubes (fSWCNTs), and finally, the AONP-PANI-SWCNT nanocomposite. The electrochemical properties of the modified electrodes regarding endosulfan detection were investigated via cyclic voltammetry (CV) and square-wave voltammetry. The current response of the electrodes to EDS followed the trend GCE-AONP-PANI-SWCNT (−510 µA) > GCE-PANI (−59 µA) > GCE-AONPs (−11.4 µA) > GCE (−5.52 µA) > GCE-fSWCNTs (−0.168 µA). The obtained results indicated that the current response obtained at the AONP-PANI-SWCNT/GCE was higher with relatively low overpotential compared to those from the other electrodes investigated. This demonstrated the superiority of the AONP-PANI-SWCNT-modified GCE. The AONP-PANI-SWCNT/GCE demonstrated good electrocatalytic activities for the electrochemical reduction of EDS. The results obtained in this study are comparable with those in other reports. The sensitivity, limit of detection (LoD), and limit of quantification (LoQ) of AONP-PANI-SWCNT/GCE towards EDS was estimated to be 0.0623 µA/µM, 6.8 µM, and 20.6 µM, respectively. Selectivity, as well as the practical application of the fabricated sensor, were explored, and the results indicated that the EDS-reduction current was reduced by only 2.0% when interfering species were present, whilst average recoveries of EDS in real samples were above 97%.

scholarly journals Low-energy room-temperature optical switching in mixed-dimensionality nanoscale perovskite heterojunctions

2021 ◽  
Vol 7 (18) ◽  
pp. eabf1959
Author(s):  
Ji Hao ◽  
Young-Hoon Kim ◽  
Severin N. Habisreutinger ◽  
Steven P. Harvey ◽  
Elisa M. Miller ◽  
...  
Keyword(s):  
Optical Switching ◽  
Room Temperature ◽  
Optical Memory ◽  
Low Energy ◽  
Optical Measurements ◽  
Ion Migration ◽  
Metal Halide Perovskite ◽  
Conductance Changes ◽  
Optical Domain ◽  
Walled Carbon Nanotubes

Long-lived photon-stimulated conductance changes in solid-state materials can enable optical memory and brain-inspired neuromorphic information processing. It remains challenging to realize optical switching with low-energy consumption, and new mechanisms and design principles giving rise to persistent photoconductivity (PPC) can help overcome an important technological hurdle. Here, we demonstrate versatile heterojunctions between metal-halide perovskite nanocrystals and semiconducting single-walled carbon nanotubes that enable room-temperature, long-lived (thousands of seconds), writable, and erasable PPC. Optical switching and basic neuromorphic functions can be stimulated at low operating voltages with femto- to pico-joule energies per spiking event, and detailed analysis demonstrates that PPC in this nanoscale interface arises from field-assisted control of ion migration within the nanocrystal array. Contactless optical measurements also suggest these systems as potential candidates for photonic synapses that are stimulated and read in the optical domain. The tunability of PPC shown here holds promise for neuromorphic computing and other technologies that use optical memory.

scholarly journals A Unique Strategy for Polyethylene Glycol/Hybrid Carbon Foam Phase Change Materials: Morphologies, Thermal Properties, and Energy Storage Behavior

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2011 ◽  
Author(s):  
Xiaolong Su ◽  
Shikui Jia ◽  
Guowei Lv ◽  
Demei Yu
Keyword(s):  
Carbon Nanotubes ◽  
Polyethylene Glycol ◽  
Energy Storage ◽  
Phase Change ◽  
Thermal Energy ◽  
Phase Change Materials ◽  
Carbon Foam ◽  
Chemical Structures ◽  
Walled Carbon Nanotubes ◽  
Hybrid Carbon

Polyethylene glycol (PEG)/hybrid carbon foam (CF) phase change materials (PCMs) were prepared by integrating PEG into CF via dynamic-vacuum impregnation. The hybrid CF was first synthesized by mixtures of graphene oxide (GO) and carbon nanotubes (CNTs) with different volume ratios. The morphologies, chemical structures, thermal conductivities, shape-stabilization levels, and photo-thermal energy conversion levels of these composite PCMs were characterized systematically. The prepared composite PCMs exhibited good shape-stabilization levels and showed their original shapes without any PEG leakage. It was found that the polyethylene glycol/carbon foam with multi-walled carbon nanotubes (PEG/MCF) composite PCMs had a better shape-stable performance below the temperature of 250 °C, and the thermal conductivity of the PEG/MCF composite PCMs reached as high as 1.535 W/(mK), which was obviously higher than that of polyethylene glycol/carbon foam with single-walled carbon nanotubes (PEG/SCF, 1.159 W/(mK)). The results of the photo-thermal simulation tests showed that the composite PCMs had the ability to absorb light energy and then convert it to thermal energy, and the maximum thermal energy storage efficiency of the PEG/MCF composite PCMs and the PEG/SCF composite PCMs was 92.1% and 90.6%, respectively. It was considered that a valuable technique to produce high-performance composite PCMs was developed.

scholarly journals Diameter and Length Effect on Diffusive-Ballistic Phonon Transport in a Carbon Nanotube

2007 ◽  
Author(s):  
Junichiro Shiomi ◽  
Shigeo Maruyama
Keyword(s):  
Thermal Conductivity ◽  
Room Temperature ◽  
Single Walled Carbon Nanotubes ◽  
Phonon Transport ◽  
Boundary Resistance ◽  
Gradual Transition ◽  
Length Effect ◽  
Control Techniques ◽  
Non Equilibrium Molecular Dynamics ◽  
Walled Carbon Nanotubes

We report a non-equilibrium molecular dynamics (MD) study on heat conduction of finite-length single-walled carbon nanotubes (SWNTs). The length and diameter dependences of the thermal conductivity are quantified for a range of nanotube-lengths up to a micrometer at room temperature using two different temperature control techniques. A thorough investigation was carried out on the influence of intrinsic thermal boundary resistance between the temperature-controlled layers and the rest of the SWNT. The trend of length effect indicates a gradual transition from nearly pure ballistic phonon transport to diffusive-ballistic phonon transport. The nearly pure ballistic phonon transport was also confirmed by the minor diameter-dependence of thermal conductivity for short SWNTs. For longer SWNTs with stronger diffusive effect, the thermal conductivity is larger for SWNTs with smaller diameters.

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