Graphene-enhanced metal oxide gas sensors at room temperature: a review

• Dongjin Sun,
• Yifan Luo,
• Marc Debliquy and
• Chao Zhang

Beilstein J. Nanotechnol. 2018, 9, 2832–2844, doi:10.3762/bjnano.9.264

• . The improved experimental schemes are raised and the critical research directions of graphene/metal-oxide sensors in the future are proposed. Keywords: gas sensor; graphene; metal oxide; nitrogen dioxide (NO2); room temperature; Review Introduction Since the discovery by Novoselov and Geim [1

• , thus converting it to a semiconductor. Choi et al. [11] prepared GO room-temperature gas sensors by a modified Hummers method. The group found that the sensitivity and repeatability of the sensor depended on the amount of oxygen functional groups on the surface of GO. Moreover, hydroxy groups were the

• ]. The oxygen functional groups that locate on the surface of rGO lead to an electron transfer from rGO to oxygen functional groups, and holes become the main charge carriers, indicating that rGO acts as a p-type semiconductor [14][15][16]. Zhang et al. [17] prepared rGO room-temperature gas sensor with

Accurate control of the covalent functionalization of single-walled carbon nanotubes for the electro-enzymatically controlled oxidation of biomolecules

• Naoual Allali,
• Veronika Urbanova,
• Mathieu Etienne,
• Xavier Devaux,
• Martine Mallet,
• Brigitte Vigolo,
• Jean-Joseph Adjizian,
• Chris P. Ewels,
• Sven Oberg,
• Alexander V. Soldatov,
• Edward McRae,
• Yves Fort,
• Manuel Dossot and
• Victor Mamane

Beilstein J. Nanotechnol. 2018, 9, 2750–2762, doi:10.3762/bjnano.9.257

• arising from the non-covalent interaction between CNTs and the electron mediator is that the latter may diffuse inside the analyzed medium, resulting in a progressive decrease of the sensor efficiency. A good alternative is therefore to covalently graft an electron mediator onto the CNT sidewalls. While

Au–Si plasmonic platforms: synthesis, structure and FDTD simulations

• Anna Gapska,
• Marcin Łapiński,
• Paweł Syty,
• Wojciech Sadowski,
• Józef E. Sienkiewicz and
• Barbara Kościelska

Beilstein J. Nanotechnol. 2018, 9, 2599–2608, doi:10.3762/bjnano.9.241

• on the sample. The time envelope of the pulse was set to be rectangular. It provided the single wavelength of 395 nm (which is the off-resonant transition for Si) for exactly 10 fs. The sensor was placed in the zx-plane, 10 nm above the Si substrate. The second simulation, by using FDTD and discrete

• . The sensor was placed in the zx-plane, between the light source and the nanoparticle layer, to allow for recording both incident and reflected fluxes. In both cases the pulse propagated along the y-axis, perpendicular to the sample surface, and was of a collimated phase front with a power of 1 W; the

Effective sensor properties and sensitivity considerations of a dynamic co-resonantly coupled cantilever sensor

• Julia Körner

Beilstein J. Nanotechnol. 2018, 9, 2546–2560, doi:10.3762/bjnano.9.237

• nanocantilever alters the oscillatory state of the coupled system as a whole and can be detected at the microcantilever. The amplitude response curve of the microcantilever exhibits two resonance peaks and their response to an interaction applied to the sensor depends on the properties of the individual beams

• behaviour it is crucial to derive a description for these effective sensor properties. Results: By modeling the co-resonantly coupled system as a coupled harmonic oscillator and using electromechanical analogies, analytical expressions for the effective sensor properties have been derived and discussed. To

• illustrate the findings, numerical values for an exemplary system based on experimental sensor realizations have been employed. The results give insight into the complex interplay between the individual subsystem’s properties and the frequency matching, leading to a rather large parameter space for the co

ZnO-nanostructure-based electrochemical sensor: Effect of nanostructure morphology on the sensing of heavy metal ions

• Marina Krasovska,
• Vjaceslavs Gerbreders,
• Irena Mihailova,
• Andrejs Ogurcovs,
• Eriks Sledevskis,
• Andrejs Gerbreders and
• Pavels Sarajevs

Beilstein J. Nanotechnol. 2018, 9, 2421–2431, doi:10.3762/bjnano.9.227

• most harmful heavy metals. Its presence is hazardous to the environment, it is toxic and carcinogenic, and it tends to accumulate in living organisms, where it replaces other elements in bones and tissues, and causes long-term poisoning [3][4][5]. That is why the creation of a sensor that could detect

• chemicals even at very low concentrations [12][13][14]. Furthermore, combined with a sensor platform based on nanomaterials and nanostructures, these electrochemical methods contribute to the improvement of sensor performance in terms of sensitivity and specificity, primarily as a result of the large

• electrochemical sensor of heavy metal ions. In this work, using the hydrothermal method, nanostructures of ZnO were synthesized in four different morphologies: nanorods (NRs), nanoneedles (NNs), nanotubes (NTs) and nanoplates (NPs). The samples described in this article were obtained using a preparation protocol

Dumbbell gold nanoparticle dimer antennas with advanced optical properties

• Janning F. Herrmann and
• Christiane Höppener

Beilstein J. Nanotechnol. 2018, 9, 2188–2197, doi:10.3762/bjnano.9.205

• maintained with sub-nanometer accuracy to 2–4 nm by means of a force feedback loop regulating on the frequency shift of the force sensor, which is excited at its resonance frequency. The fluorescence emission rate as a function of the antenna–sample distance is recorded with the feedback loop switched off

• sensor. Inset: SEM image of the CB[n] mediated dimer antenna attached to the pointed end of the glass tip. Scale bar: 100 nm. Antenna-enhanced fluorescence images of randomly distributed high-QY emitters on a glass surface imaged with dimer antennas with a gap size of 1.5 nm (A) and 1 nm (B), and a

Electrospun one-dimensional nanostructures: a new horizon for gas sensing materials

• Muhammad Imran,
• Nunzio Motta and
• Mahnaz Shafiei

Beilstein J. Nanotechnol. 2018, 9, 2128–2170, doi:10.3762/bjnano.9.202

• important active materials for gas sensing applications. Such highly sensitive and selective elements can be embedded in sensor nodes for internet-of-things applications or in mobile systems for continuous monitoring of air pollutants and greenhouse gases as well as for monitoring the well-being and health

• followed by death. Gas sensors are the primary devices used for the detection and monitoring of these pollutants. Employing nanotechnology in sensor applications has significantly improved the performance of such devices, providing enhanced sensitivity, selectivity, low power consumption and high

• sensors have found widespread commercial applications [91][92] due to their simplicity and enhanced gas sensing performance (high sensitivity, fast response/recovery and low operating temperature) and low cost. A typical conductometric gas sensor consists of an active sensing layer in which conductivity

Synthesis of hafnium nanoparticles and hafnium nanoparticle films by gas condensation and energetic deposition

• Irini Michelakaki,
• Nikos Boukos,
• Dimitrios A. Dragatogiannis,
• Spyros Stathopoulos,
• Costas A. Charitidis and
• Dimitris Tsoukalas

Beilstein J. Nanotechnol. 2018, 9, 1868–1880, doi:10.3762/bjnano.9.179

• demonstrate high catalytic activity during hydrogenation of levulinic acid [17], nickel NPs, which find application as electrochemical sensor [18], and cobalt NPs, which exhibit high magnetic anisotropy [19]. Recently, we have reported that hcp hafnium nanoparticles fabricated by inert-gas condensation, when

Quantitative comparison of wideband low-latency phase-locked loop circuit designs for high-speed frequency modulation atomic force microscopy

• Kazuki Miyata and
• Takeshi Fukuma

Beilstein J. Nanotechnol. 2018, 9, 1844–1855, doi:10.3762/bjnano.9.176

• improvements in bandwidth or resonance frequency of all of the components constituting the tip–sample distance regulation loop, such as the cantilever, cantilever excitation unit, cantilever deflection sensor, scanner, feedback controller, and phase-locked loop (PLL) circuit. In particular, the PLL circuit is

• excited and detected using a highly stable custom-built photothermal excitation system and low-noise optical beam deflection sensor, respectively [27][28][29][30]. The noise spectra shown below in Figure 8 were obtained using the commercially available AFM controller (ARC2, Asylum Research). Sample

• other components in the cantilever excitation loop such as the ADC/DAC, cantilever, cantilever excitation unit, and cantilever deflection sensor. The demodulated signal is output from the DAC and analyzed by an external frequency response analyzer. We used f0 values of 150 kHz and 3 MHz, which are

Tunable fractional Fourier transform implementation of electronic wave functions in atomically thin materials

• Daniela Dragoman

Beilstein J. Nanotechnol. 2018, 9, 1828–1833, doi:10.3762/bjnano.9.174

• currents/signals from waveguide or sensor arrays [29][30][31] (to mention only a few references). Indeed, the inverse scattering problem has extensive applications in everyday life, so that retrieval algorithms exist or can be adapted for virtually any situation. Conclusion In conclusion, a parabolic

Direct AFM-based nanoscale mapping and tomography of open-circuit voltages for photovoltaics

• Katherine Atamanuk,
• Justin Luria and
• Bryan D. Huey

Beilstein J. Nanotechnol. 2018, 9, 1802–1808, doi:10.3762/bjnano.9.171

• including many sensor and solar cell designs. For thin film solar cells such as CdTe, the open-circuit voltage and short-circuit current are especially critical performance indicators, often varying between and even within individual grains. A new method for directly mapping the open-circuit voltage

Free-radical gases on two-dimensional transition-metal disulfides (XS₂, X = Mo/W): robust half-metallicity for efficient nitrogen oxide sensors

• Chunmei Zhang,
• Yalong Jiao,
• Fengxian Ma,
• Sri Kasi Matta,
• Steven Bottle and
• Aijun Du

Beilstein J. Nanotechnol. 2018, 9, 1641–1646, doi:10.3762/bjnano.9.156

• the gas molecules remains unclear. In addition to MoS2, 2D WS2 is expected to be a more promising material as gas sensor because of its higher thermal stability and wider temperature range of operation [18]. Synthesized FETs layered with WS2 are also reported as attractive electronic devices [27

• , GaSe, SnS, SnSe, WSe and Bi2Se3 (Figure S1, Supporting Information File 1). To the best of our knowledge, our work is the first to propose a NO sensor by detecting spin transmission, which may probe a new prospect for gas sensing. Computational Methods The spin-polarized calculations for NO, NO2, and

• NOx onto MoS2, indicating highly thermal stability.” Conclusion We have presented monolayer XS2 (X = Mo, W) as NO sensor based on first principles studies. The adsorption sites and energy for NO and NO2 molecules on MoS2 or WS2 layers have been studied. The calculations were carried out with different

Photoluminescence of CdSe/ZnS quantum dots in nematic liquid crystals in electric fields

• Margarita A. Kurochkina,
• Elena A. Konshina and
• Daria Khmelevskaia

Beilstein J. Nanotechnol. 2018, 9, 1544–1549, doi:10.3762/bjnano.9.145

• demonstrate unique properties such as high quantum yield, narrow symmetric luminescence peak and high photostability, which are used in optical molecular sensor systems [1], bioanalysis [2], solar cells [3][4], and light-emitting devices [5]. The application of external electric fields to semiconductor NPs

Surface characterization of nanoparticles using near-field light scattering

• Eunsoo Yoo,
• Yizhong Liu,
• Chukwuazam A. Nwasike,
• Sebastian R. Freeman,
• Brian C. DiPaolo,
• Bernardo Cordovez and
• Amber L. Doiron

Beilstein J. Nanotechnol. 2018, 9, 1228–1238, doi:10.3762/bjnano.9.114

• was restricted to 10 μL/min range using a proportional integral derivative (PID) controller and an in-line flow rate sensor. Nanoparticles that flow closer to the waveguide are usually trapped within the evanescent field and are pushed along the waveguide by laser radiation pressure. NLS custom

Electrodeposition of reduced graphene oxide with chitosan based on the coordination deposition method

• Mingyang Liu,
• Yanjun Chen,
• Chaoran Qin,
• Zheng Zhang,
• Shuai Ma,
• Xiuru Cai,
• Xueqian Li and
• Yifeng Wang

Beilstein J. Nanotechnol. 2018, 9, 1200–1210, doi:10.3762/bjnano.9.111

• both reveal that the electrodeposition method in this work provides a controllable means to fabricate the rGO nanocomposite films in different shapes. Electrodeposited HACC-rGO/CS films for electrochemical detection Graphene has drawn extensive interest in sensor applications due to its favorable

Scanning speed phenomenon in contact-resonance atomic force microscopy

• Christopher C. Glover,
• Jason P. Killgore and
• Ryan C. Tung

Beilstein J. Nanotechnol. 2018, 9, 945–952, doi:10.3762/bjnano.9.87

• cyanoacrylate. A razor blade was then used to cleave the sample, leaving behind a pristine sample surface. The sample was placed in a closed AFM flow-cell with an integrated relative humidity sensor. A cantilever with spring constant kL = 1.7 ± 0.2 N/m and first free resonance = 61.85 ± 0.1 kHz was mounted to

Facile chemical routes to mesoporous silver substrates for SERS analysis

• Elina A. Tastekova,
• Alexander Y. Polyakov,
• Anastasia E. Goldt,
• Alexander V. Sidorov,
• Alexandra A. Oshmyanskaya,
• Irina V. Sukhorukova,
• Dmitry V. Shtansky,
• Wolgang Grünert and
• Anastasia V. Grigorieva

Beilstein J. Nanotechnol. 2018, 9, 880–889, doi:10.3762/bjnano.9.82

• long time in air. Mesoporous noble metals are mostly used as catalysts for high surface energy, gas sensor components, cell imaging mediators, etc. [5]. The most popular methods for mesoporous metal processing include acidic etching of bimetallic molts [6], electrochemical dealloying [7

Perfusion double-channel micropipette probes for oxygen flux mapping with single-cell resolution

• Yang Gao,
• Bin Li,
• Riju Singhal,
• Adam Fontecchio,
• Ben Pelleg,
• Zulfiya Orynbayeva,
• Yury Gogotsi and
• Gary Friedman

Beilstein J. Nanotechnol. 2018, 9, 850–860, doi:10.3762/bjnano.9.79

• to employ a system where linear oxygen gradients are measured by moving a sensor along a small tube with the embryo (a group of cells) at one end [34]. This technique demonstrated the ability to measure respiration rates of around 0.7 fmol/s, which is 100–1000 times faster than typical oxygen

• increased pipette diameter One influence of the pipette is the confinement of oxygen diffusion within it. Oxygen can diffuse freely along the pipette axis (z-axis as in Figure 3a), but remains confined by the pipette walls. To demonstrate the effect of this confined diffusion, consider a small oxygen sensor

• solution in water at room temperature and the oxygen concentration at the specific point under investigation) obtained by the sensor positioned at the tip of the pipette has around 1.5 times greater signal than the same size sensor placed at the same distance away from the cell, but without the pipette

Surface-plasmon-enhanced ultraviolet emission of Au-decorated ZnO structures for gas sensing and photocatalytic devices

• T. Anh Thu Do,
• Truong Giang Ho,
• Thu Hoai Bui,
• Quang Ngan Pham,
• Hong Thai Giang,
• Thi Thu Do,
• Duc Van Nguyen and
• Dai Lam Tran

Beilstein J. Nanotechnol. 2018, 9, 771–779, doi:10.3762/bjnano.9.70

• . Keywords: Au-decorated ZnO; carrier dynamics; gas sensors; photocatalyst; SPR effect; Introduction Inorganic transition metal oxide sensor devices have attracted attention in particular for improving gas sensing, energy conversion, electronics, photocatalysis and optoelectronic devices [1][2][3][4]. Among

• quantity of active electrons involved in the surface response plays a key role for the sensor performance. The incorporation of noble metal nanostructures such as gold (Au) into ZnO surfaces is considered as an effective way to enhance the gas sensing response and to reduce the operation temperature and

• and reasonably fast response/recovery time were reported for a gas sensor based on Au-decorated ZnO structures. The highest selectivity towards NO2 was compared to other combustion gases such as CO, and C3H8. In addition, the photocatalytic decomposition of organic dyes under sunlight using PL

The effect of atmospheric doping on pressure-dependent Raman scattering in supported graphene

• Egor A. Kolesov,
• Mikhail S. Tivanov,
• Olga V. Korolik,
• Olesya O. Kapitanova,
• Xiao Fu,
• Hak Dong Cho,
• Tae Won Kang and
• Gennady N Panin

Beilstein J. Nanotechnol. 2018, 9, 704–710, doi:10.3762/bjnano.9.65

• counterbalance the excess charge carriers. In addition, it turned out that atmosphere-induced doping decreases charge carrier inhomogeneity in nitrogen-doped graphene. For the undoped graphene samples, the opposite effect occurs. The results of the present study are useful for graphene-based sensor design

Perovskite-structured CaTiO₃ coupled with g-C₃N₄ as a heterojunction photocatalyst for organic pollutant degradation

• Ashish Kumar,
• Christian Schuerings,
• Suneel Kumar,
• Ajay Kumar and
• Venkata Krishnan

Beilstein J. Nanotechnol. 2018, 9, 671–685, doi:10.3762/bjnano.9.62

• earth-abundant carbon and nitrogen elements and the low cost of the initial precursors promotes it as a promising photocatalytic material for diverse applications, such as energy generation [17][18][19], sensor [20], and fuel cell applications [21], as well as environmental remediation [22]. The band

Sensing behavior of flower-shaped MoS₂ nanoflakes: case study with methanol and xylene

• Maryam Barzegar,
• Masoud Berahman and
• Azam Iraji zad

Beilstein J. Nanotechnol. 2018, 9, 608–615, doi:10.3762/bjnano.9.57

• functional theory; gas sensor; hydrothermal method; methanol; MoS2 nanoflakes; xylene vapor; Introduction Recent efforts in exploring two-dimensional (2D) materials have led to the introduction of a new family of materials known as transition metal dichalcogenides (TMDs), which show remarkable electrical

• a good sensor to detect acetone with response to methanol [14]. There are also investigations that marked the high response of MoS2 toward methanol and ethanol [15]. Besides these experimental reports, there are numerous theoretical investigations which illustrate the potential of MoS2 for detecting

• various gas molecules [25][26]. Among these reports, the properties of flower-shaped MoS2 as a gas sensor is underestimated, hence in this paper, we demonstrate this potential. The flower-shaped MoS2 can easily be grown using the inexpensive hydrothermal technique with high quality and in large quantity

Colloidal solution of silver nanoparticles for label-free colorimetric sensing of ammonia in aqueous solutions

• Alessandro Buccolieri,
• Antonio Serra,
• Gabriele Giancane and
• Daniela Manno

Beilstein J. Nanotechnol. 2018, 9, 499–507, doi:10.3762/bjnano.9.48

• (NH3) in the concentration range from 10−2 to 103 ppm to develop an optical sensor for NH3 in aqueous solutions. Ammonia affects the features of the nanoparticles obtained in a concentration-dependent manner as determined by UV–vis absorption analysis and TEM observations. Structural and morphological

• analysis provides the basis for the production of a colorimetric label-free sensor for ammonia. Overall, surface plasmon resonance increases when ammonia concentration rises, although the functional trend is not the same over the entire investigated ammonia concentration range. Three different ranges have

• potentially useful for colorimetric measurements [16]. A colloidal solution of silver nanoparticles was developed for a colorimetric sensor for triethylamine [17]. So far, many authors reported the effect of ammonia on the synthesis of silver nanoparticles in colloidal solutions. In particular, it is possible

Electron interaction with copper(II) carboxylate compounds

• Michal Lacko,
• Peter Papp,
• Iwona B. Szymańska,
• Edward Szłyk and
• Štefan Matejčík

Beilstein J. Nanotechnol. 2018, 9, 384–398, doi:10.3762/bjnano.9.38

• -induced deformation, and electromigration resistance which is higher than for aluminum [24][25][26][27]. Copper nanostructures, especially nanowires, are applied in opto-electronic devices, solar cells, field-emission displays, catalysis, electronic skins, and sensor devices. Moreover, they can find

Liquid-crystalline nanoarchitectures for tissue engineering

• Baeckkyoung Sung and
• Min-Ho Kim

Beilstein J. Nanotechnol. 2018, 9, 205–215, doi:10.3762/bjnano.9.22

• an additional benefit for inventing sensor devices for biomedical applications. In spite of these advantages and functionalities, the application of LC nanoarchitectures in the field of tissue engineering still remains in its infancy, when compared to the advance in the applications to LC display