1
|
Pereira N, Rezende N, Cunha THR, Barboza APM, Silva GG, Lippross D, Neves BRA, Chacham H, Ferlauto AS, Lacerda RG. Aerosol-Printed MoS 2 Ink as a High Sensitivity Humidity Sensor. ACS OMEGA 2022; 7:9388-9396. [PMID: 35356695 PMCID: PMC8945157 DOI: 10.1021/acsomega.1c06525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 03/01/2022] [Indexed: 05/13/2023]
Abstract
Molybdenum disulfide (MoS2) is attractive for use in next-generation nanoelectronic devices and exhibits great potential for humidity sensing applications. Herein, MoS2 ink was successfully prepared via a simple exfoliation method by sonication. The structural and surface morphology of a deposited ink film was analyzed by scanning electron microscopy (SEM), Raman spectroscopy, and atomic force microscopy (AFM). The aerosol-printed MoS2 ink sensor has high sensitivity, with a conductivity increase by 6 orders of magnitude upon relative humidity increase from 10 to 95% at room temperature. The sensor also has fast response/recovery times and excellent repeatability. Possible mechanisms for the water-induced conductivity increase are discussed. An analytical model that encompasses two ionic conduction regimes, with a percolation transition to an insulating state below a low humidity threshold, describes the sensor response successfully. In conclusion, our work provides a low-cost and straightforward strategy for fabricating a high-performance humidity sensor and fundamental insights into the sensing mechanism.
Collapse
Affiliation(s)
- Neuma
M. Pereira
- Departamento
de Física, Universidade Federal de
Minas Gerais, Belo Horizonte, Minas Gerais 31270-90, Brazil
- Departamento
de Química, Universidade Federal
de Minas Gerais, Belo Horizonte, Minas Gerais 31270-90, Brazil
- Centro
de Tecnologia em Nanomateriais e Grafeno/UFMG, Universidade Federal de Minas Gerais, BHtec, Belo Horizonte, Minas Gerais 31310-260, Brazil
| | - Natália
P. Rezende
- Departamento
de Física, Universidade Federal de
Minas Gerais, Belo Horizonte, Minas Gerais 31270-90, Brazil
- Centro
de Tecnologia em Nanomateriais e Grafeno/UFMG, Universidade Federal de Minas Gerais, BHtec, Belo Horizonte, Minas Gerais 31310-260, Brazil
| | - Thiago H. R. Cunha
- Departamento
de Física, Universidade Federal de
Minas Gerais, Belo Horizonte, Minas Gerais 31270-90, Brazil
- Centro
de Tecnologia em Nanomateriais e Grafeno/UFMG, Universidade Federal de Minas Gerais, BHtec, Belo Horizonte, Minas Gerais 31310-260, Brazil
| | - Ana P. M. Barboza
- Departamento
de Física, Universidade Federal de
Ouro Preto, Ouro Preto, Minas Gerais 35400-000, Brazil
| | - Glaura G. Silva
- Departamento
de Química, Universidade Federal
de Minas Gerais, Belo Horizonte, Minas Gerais 31270-90, Brazil
- Centro
de Tecnologia em Nanomateriais e Grafeno/UFMG, Universidade Federal de Minas Gerais, BHtec, Belo Horizonte, Minas Gerais 31310-260, Brazil
| | - Daniel Lippross
- Departamento
de Química, Universidade Federal
de Minas Gerais, Belo Horizonte, Minas Gerais 31270-90, Brazil
| | - Bernardo R. A. Neves
- Departamento
de Física, Universidade Federal de
Minas Gerais, Belo Horizonte, Minas Gerais 31270-90, Brazil
| | - Hélio Chacham
- Departamento
de Física, Universidade Federal de
Minas Gerais, Belo Horizonte, Minas Gerais 31270-90, Brazil
| | - Andre S. Ferlauto
- Centro
de Tecnologia em Nanomateriais e Grafeno/UFMG, Universidade Federal de Minas Gerais, BHtec, Belo Horizonte, Minas Gerais 31310-260, Brazil
- Centro
de Engenharia, Modelagem e Ciências Sociais Aplicadas, Universidade Federal do ABC, Santo André, São
Paulo 09210-580, Brazil
| | - Rodrigo G. Lacerda
- Departamento
de Física, Universidade Federal de
Minas Gerais, Belo Horizonte, Minas Gerais 31270-90, Brazil
- Centro
de Tecnologia em Nanomateriais e Grafeno/UFMG, Universidade Federal de Minas Gerais, BHtec, Belo Horizonte, Minas Gerais 31310-260, Brazil
| |
Collapse
|
2
|
Chopra V, Chudak M, Hensel R, Darhuber AA, Arzt E. Enhancing Dry Adhesion of Polymeric Micropatterns by Electric Fields. ACS APPLIED MATERIALS & INTERFACES 2020; 12:27708-27716. [PMID: 32436689 DOI: 10.1021/acsami.0c05077] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Micropatterned dry adhesives rely mainly on van der Waals interactions. In this paper, we explore the adhesion strength increase that can be achieved by superimposing an electrostatic field through interdigitated subsurface electrodes. Micropatterns were produced by replica molding in silicone. The adhesion forces were characterized systematically by means of experiments and numerical modeling. The force increased with the square of the applied voltage for electric fields up to 800 V. For larger fields, a less-than-quadratic scaling was observed, which is likely due to the small, field-dependent electrical conductivity of the materials involved. The additional adhesion force was found to be up to twice of the field-free adhesion. The results suggest an alternative method for the controlled handling of fragile or miniaturized objects.
Collapse
Affiliation(s)
- Vaishali Chopra
- INM-Leibniz Institute for New Materials, 66123 Saarbrücken, Germany
- Department of Materials Science and Engineering, Saarland University, 66123 Saarbrücken, Germany
| | - Maciej Chudak
- Department of Applied Physics, Eindhoven University of Technology, 5600 MB Eindhoven, Netherlands
| | - René Hensel
- INM-Leibniz Institute for New Materials, 66123 Saarbrücken, Germany
| | - Anton A Darhuber
- Department of Applied Physics, Eindhoven University of Technology, 5600 MB Eindhoven, Netherlands
| | - Eduard Arzt
- INM-Leibniz Institute for New Materials, 66123 Saarbrücken, Germany
- Department of Materials Science and Engineering, Saarland University, 66123 Saarbrücken, Germany
| |
Collapse
|
5
|
Abstract
The conductivity of DNA in molecular junctions is often probed experimentally under dry conditions, but it is unclear how much of the solvent remains attached to the DNA and how this impacts its structure, electronic states, and conductivity. Classical MD simulations show that DNA is unstable if the solvent is removed completely, while a micro-hydrated system with few water molecules shows similar charge transport properties as fully solvated DNA does. This surprising effect is analyzed in detail by mapping the density functional theory-based electronic structure to a tight-binding Hamiltonian, allowing for an estimate of conductivity of various DNA sequences with snapshot-averaged Landauer's approach. The characteristics of DNA charge transport turn out to be determined by the nearest hydration shell(s), and the removal of bulk solvent has little effect on the transport.
Collapse
Affiliation(s)
- Mario Wolter
- Institute of Physical Chemistry, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | | | | |
Collapse
|
6
|
Haspel H, Bugris V, Kukovecz Á. Water-induced changes in the charge-transport dynamics of titanate nanowires. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:1977-1984. [PMID: 24494714 DOI: 10.1021/la4048374] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The temperature dependence of dielectric processes in humid titanate nanowires was investigated via broadband dielectric spectroscopy under quasi-isosteric conditions in the temperature range of 150-350 K. It was found that the dynamic parameters obtained from low-temperature measurements cannot describe the dielectric behavior of the system above 273 K, implying changes in the dynamics of the corresponding dielectric processes. The calculated activation energies and pre-exponential factors counterintuitively increase linearly with the amount of adsorbed water, and a compensation effect was also found to apply to all contributions in the TiONW spectra.
Collapse
Affiliation(s)
- Henrik Haspel
- Department of Applied and Environmental Chemistry, University of Szeged , Rerrich Béla tér 1, H-6720 Szeged, Hungary
| | | | | |
Collapse
|
9
|
Warshavsky VB, Podguzova TS, Tatyanenko DV, Shchekin AK. Vapor nucleation on a wettable nanoparticle carrying a non-central discrete electric charge. J Chem Phys 2013; 138:194708. [PMID: 23697431 DOI: 10.1063/1.4804655] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
We have studied thermodynamics of vapor nucleation on a spherical wettable dielectric nanoparticle carrying a discrete electric charge located at a certain distance from the particle center. New general equations for the chemical potential of a condensate molecule in the droplet around the particle, the work of the droplet formation and the droplet shape as functions of the effective radius of condensate film, and the value of an electric charge and its location with respect to the particle center have been derived analytically. These equations take into account both the effects of the non-central electric field and the disjoining pressure in the thin liquid film forming the droplet. Under the assumption of small distortion of the droplet shape in the axisymmetric electric field of non-central discrete charge from the spherical one, these equations have been simultaneously solved analytically. The obtained explicit formulas for the condensate chemical potential, the work of droplet formation, and the droplet shape have been numerically investigated for the case of the charge adsorbed below and above the surface of the particle. It has been shown that the effect of the electric field of non-central charge reveals itself in decreasing the maximum value of the condensate chemical potential in the droplet and shifting it away from the particle surface. As a result, the threshold value of the vapor supersaturation for barrierless nucleation and the activation barrier for barrier nucleation on the charged nanosized nuclei diminish in comparison with nucleation on nuclei with central charge. The effect is larger for smaller nuclei. It decreases with increase in the dielectric constant of the nuclei in the case of charge location below the particle surface.
Collapse
Affiliation(s)
- V B Warshavsky
- Department of Statistical Physics, Faculty of Physics, St. Petersburg State University, Ulyanovskaya 1, Petrodvoretz, St. Petersburg 198504, Russian Federation
| | | | | | | |
Collapse
|