Study of the correlation between sensing performance and surface morphology of inkjet-printed aqueous graphene-based chemiresistors for NO₂ detection

• F. Villani,
• C. Schiattarella,
• T. Polichetti,
• R. Di Capua,
• F. Loffredo,
• B. Alfano,
• M. L. Miglietta,
• E. Massera,
• L. Verdoliva and
• G. Di Francia

Beilstein J. Nanotechnol. 2017, 8, 1023–1031, doi:10.3762/bjnano.8.103

• 15 min for removing the residual solvent. Sensing analysis Tests for sensing measurements upon NO2 have been performed in the gas sensor characterization system (GSCS, Kenosistec equipment) equipped with a stainless steel chamber placed in a thermostatic box, keeping constant the temperature (T = 22

CVD transfer-free graphene for sensing applications

• Chiara Schiattarella,
• Sten Vollebregt,
• Tiziana Polichetti,
• Brigida Alfano,
• Ettore Massera,
• Maria Lucia Miglietta,
• Girolamo Di Francia and
• Pasqualina Maria Sarro

Beilstein J. Nanotechnol. 2017, 8, 1015–1022, doi:10.3762/bjnano.8.102

• number of publications dedicated to graphene-based sensors [2]. The gas sensor devices presented in literature are mostly based on pristine graphene, graphene oxide (GO) and reduced graphene oxide (rGO). Many approaches for the fabrication of such materials, including CVD, mechanical, chemical and

• different points of the sensing strips by means of Renishaw InVia Reflex spectrometer, at λ = 514 nm and 20 mW incident laser power, in backscattering configuration. The chemiresistors have been tested in a Gas Sensor Characterization System (GSCS, Kenosistec equipment) consisting of a stainless steel

Synthesis of graphene–transition metal oxide hybrid nanoparticles and their application in various fields

• Arpita Jana,
• Elke Scheer and
• Sebastian Polarz

Beilstein J. Nanotechnol. 2017, 8, 688–714, doi:10.3762/bjnano.8.74

• –graphene hybrids, was used as a high-performance NO2 gas sensor (Figure 8). Copper oxide (CuO) is also a p-type semiconductor. CuO–graphene composites have also been used as anode material for LIBs [211][215]. Mathesh et al. prepared GO hybrid materials consisting of Cu ions complexed with GO, where Cu2

Gas sensing properties of MWCNT layers electrochemically decorated with Au and Pd nanoparticles

• Elena Dilonardo,
• Michele Penza,
• Marco Alvisi,
• Riccardo Rossi,
• Gennaro Cassano,
• Cinzia Di Franco,
• Francesco Palmisano,
• Luisa Torsi and
• Nicola Cioffi

Beilstein J. Nanotechnol. 2017, 8, 592–603, doi:10.3762/bjnano.8.64

• with the highest Pd loading showed the highest sensitivity when operated at 100 °C. Finally, considering the reported gas sensing results, sensing mechanisms have been proposed, correlating the chemical composition and gas sensing responses. Keywords: Au nanoparticle; chemiresistive gas sensor

• standards established by Kyoto and Paris climate agreements [2][3]. Besides the expensive and time-consuming analytical instrumentation (e.g., gas chromatography) commonly used to control the concentration of released gases, some progress has been made in gas sensor technologies as a valid alternative in

• gas detection. Indeed, gas sensor systems have unique properties such as, easy and low-cost production, low operating temperature, electronic and thermal stability, good sensitivity but poor selectivity in gas detection [4]. In this context, the development of nanostructured materials has contributed

Graphene functionalised by laser-ablated V₂O₅ for a highly sensitive NH₃ sensor

• Margus Kodu,
• Artjom Berholts,
• Tauno Kahro,
• Mati Kook,
• Peeter Ritslaid,
• Helina Seemen,
• Tea Avarmaa,
• Harry Alles and
• Raivo Jaaniso

Beilstein J. Nanotechnol. 2017, 8, 571–578, doi:10.3762/bjnano.8.61

• between deposited V2O5 and graphene. Keywords: ammonia; electric conductivity; gas sensor; graphene; pulsed laser deposition; UV light activation; vanadium(V) oxide; Introduction Graphene, being a thin (semi)conducting material, is a promising gas sensing system. Highly sensitive response, down to

• Raman spectrum from graphene placed between the electrodes of the gas sensor structure (see Experimental section). The G and 2D bands peak at ≈1590 cm−1 and ≈2690 cm−1, and have full-widths at half-maximum of 11 cm−1 and 29 cm−1, respectively. These characteristics, together with the ratio of G to 2D

• after (solid line) PLD functionalisation, measured under UV illumination at the room temperature. The grey bars indicate the duration of gas exposure for the given concentration. Photograph of a gas sensor device based on PLD-functionalised CVD graphene. The gap between the electrodes is 1 × 4 mm2. The

Impact of air exposure and annealing on the chemical and electronic properties of the surface of SnO₂ nanolayers deposited by rheotaxial growth and vacuum oxidation

• Monika Kwoka and
• Maciej Krzywiecki

Beilstein J. Nanotechnol. 2017, 8, 514–521, doi:10.3762/bjnano.8.55

• lower than moderate. This is of significant importance for the potential application as gas sensor material [16][19], because it shows that even after air exposure the layers kept their high purity and the available adsorption sites are not occupied mainly by carbonaceous species. After subsequent UHV

Colorimetric gas detection by the varying thickness of a thin film of ultrasmall PTSA-coated TiO₂ nanoparticles on a Si substrate

• Urmas Joost,
• Andris Šutka,
• Meeri Visnapuu,
• Aile Tamm,
• Meeri Lembinen,
• Mikk Antsov,
• Kathriin Utt,
• Krisjanis Smits,
• Ergo Nõmmiste and
• Vambola Kisand

Beilstein J. Nanotechnol. 2017, 8, 229–236, doi:10.3762/bjnano.8.25

• ultrasmall TiO2 nanoparticles (NPs) for a colorimetric gas sensor. The functional thin film is extremely simple, consisting of TiO2 NPs and the elastic binding agent p-toluenesulfonic acid (PTSA) on a Si substrate. It is not necessary to use particles with narrow size distributions of diameters in well

• from the film/substrate interface, as schematically demonstrated in Figure 2. The functional thin film is extremely simple, consisting of TiO2 NPs (the mean size of 3 nm was measured by TEM and DLS, Figure 3a and Figure 3e) and the binding agent PTSA on a Si substrate. It is a colorimetric gas sensor

Nanocrystalline TiO₂/SnO₂ heterostructures for gas sensing

• Barbara Lyson-Sypien,
• Anna Kusior,
• Mieczylaw Rekas,
• Jan Zukrowski,
• Marta Gajewska,
• Katarzyna Michalow-Mauke,
• Thomas Graule,
• Marta Radecka and
• Katarzyna Zakrzewska

Beilstein J. Nanotechnol. 2017, 8, 108–122, doi:10.3762/bjnano.8.12

• ) while changes of the morphological and the electronic structure dominate in the case of B) and D). Surface phenomena determine the gas-sensor response in the case of decorated nano-heterostructures, D). As shown in [6], electron transfer over n–n-type heterojunctions can account for sensor sensitization

• the response of the gas sensor. In fact, the sensitization comes to an effect in the first step of reducing gas detection, namely the preadsorption of oxygen at the grain surface (in our case it is assumed to be in the form of O− as shown in Figure 1b). The efficiency of the O− adsorption process is

• as core–shell particles. Table 1 presents some of the examples of the latest papers dealing with TiO2–SnO2 materials for the detection of different gases. The performance of a resistive-type gas sensor is inherently related to the form and number of oxygen species adsorbed at the surface of the

Sensitive detection of hydrocarbon gases using electrochemically Pd-modified ZnO chemiresistors

• Elena Dilonardo,
• Michele Penza,
• Marco Alvisi,
• Gennaro Cassano,
• Cinzia Di Franco,
• Francesco Palmisano,
• Luisa Torsi and
• Nicola Cioffi

Beilstein J. Nanotechnol. 2017, 8, 82–90, doi:10.3762/bjnano.8.9

• chemical analyses, using scanning electron microscopy and X-ray photoelectron spectroscopy, respectively. The effect of the Pd catalyst on the performance of the ZnO-based gas sensor was evaluated by comparing the sensing results with those of pristine ZnO NRs, at an operating temperature of 300 °C and for

• molecule. Finally, the evaluation of the selectivity revealed that the presence or the absence of metal nanoparticles on ZnO NRs improves the selectivity in the detection of specific HCs gaseous molecules. Keywords: chemiresistive gas sensor; electrosynthesis; hydrocarbon gas sensor; Pd-modified ZnO; ZnO

• -like ZnO-based chemiresistive gas sensor. After the annealing at 550 °C, pristine and Pd-modified ZnO were redispersed in ACN and drop-cast on alumina substrates to obtain sensing layers between gold contacts. These assemblies were subsequently thermally stabilized at 300 °C for 2 h. The description of

Nanostructured SnO₂–ZnO composite gas sensors for selective detection of carbon monoxide

• Paul Chesler,
• Cristian Hornoiu,
• Susana Mihaiu,
• Cristina Vladut,
• Jose Maria Calderon Moreno,
• Mihai Anastasescu,
• Carmen Moldovan,
• Bogdan Firtat,
• Costin Brasoveanu,
• George Muscalu,
• Ion Stan and
• Mariuca Gartner

Beilstein J. Nanotechnol. 2016, 7, 2045–2056, doi:10.3762/bjnano.7.195

• test gas [3]. This may be regarded as a simplified view of the sensing mechanism for this type of gas sensor. As an example, for typical n-type semiconductors, the overall sensor resistance increases after exposure to oxidizing gases or decreases after the sensor is exposed to reducing gases. For p

• the simulations. Based on these results, the fifth version (see Figure 3) was selected for the deposition of the sensitive layer in order to obtain the final version of the gas sensor. Transducer fabrication using mask technology/photolithography The fabrication of the transducer was carried out using

• platform (which is also the sample holder), necessary to reach the working temperature of the sensor (from room temperature to 300 °C, see Figure 6). In the sensing chamber a thermocouple was inserted to give a precise measurement of the working temperature in the atmosphere in which the gas sensor is

Surface-enhanced infrared absorption studies towards a new optical biosensor

• Lothar Leidner,
• Julia Stäb,
• Jennifer T. Adam and
• Günter Gauglitz

Beilstein J. Nanotechnol. 2016, 7, 1736–1742, doi:10.3762/bjnano.7.166

• such a combination (reported previously) is a gas sensor, which combines RIfS and MIR fingerprints as sensing principles. Gas molecules diffuse into a polymer film and cause a thickness change of the film. The thin film interference spectrum is used for determination of gas concentration

Nanostructured TiO₂-based gas sensors with enhanced sensitivity to reducing gases

• Wojciech Maziarz,
• Anna Kusior and
• Anita Trenczek-Zajac

Beilstein J. Nanotechnol. 2016, 7, 1718–1726, doi:10.3762/bjnano.7.164

• influencing the sensitivity of a gas sensor. In comparison with spherical materials or thin layers, 3D structures exhibit much more active sites, and a complex network of canals enables gaseous reagents to penetrate inside the structure. The smaller the grains, the higher the surface-to-volume ratio for a gas

• , hierarchical flower-like nanostructures obtained during the chemical oxidation process were applied in the field of gas sensor technology. The obtained sensors were analyzed as a detector of oxidizing and reducing gases. The selectivity of the nanostructures was demonstrated by a sensitivity investigation in

• . Schematic view of gas sensor measuring system. XRD patterns of TiO2-based sensors: a) T30 – TiO2 thin layer, flower-like TiO2 (NS0) and TiO2/SnO2 (NS1) nanostructures b) the most intense diffraction peaks of TiO2 (anatase, rutile) and SnO2 (cassiterite). Top-views (a,c–g) and side-views (b,h) of flower-like

Enhanced detection of nitrogen dioxide via combined heating and pulsed UV operation of indium oxide nano-octahedra

• Oriol Gonzalez,
• Sergio Roso,
• Xavier Vilanova and
• Eduard Llobet

Beilstein J. Nanotechnol. 2016, 7, 1507–1518, doi:10.3762/bjnano.7.144

• and, thus, in a decrease in the DC resistance of the gas sensor [18][19]. Furthermore, the partial removal of oxygen adsorbates may trigger the diffusion of bulk oxygen towards the surface, especially when the UV irradiated metal oxide sensor is operated at temperatures well above room temperature [20

• mA. Furthermore, the LED was placed 2 cm away from the heated area of the sensor and kept inserted in a thermally insulating housing. Therefore, no saturation effect affected our experimental set-up. A picture of the sensor chamber and of a gas sensor is shown in Figure 14. Gas mixing and delivery to

• for the UV diodes. Picture of an indium oxide gas sensor (right). Comparison of sensor response intensity, response and recovery times for an indium oxide sensor under two different operating conditions. Comparison of response time, sensitivity to nitrogen dioxide and power consumption for an indium

A composite structure based on reduced graphene oxide and metal oxide nanomaterials for chemical sensors

• Vardan Galstyan,
• Elisabetta Comini,
• Iskandar Kholmanov,
• Andrea Ponzoni,
• Veronica Sberveglieri,
• Nicola Poli,
• Guido Faglia and
• Giorgio Sberveglieri

Beilstein J. Nanotechnol. 2016, 7, 1421–1427, doi:10.3762/bjnano.7.133

• and ZnO with a highly improved performance in sensing the VOCs ethanol and acetone. The highly improved sensing behavior of the obtained structures shows that our hybrid nanomaterial may be used to fabricate gas sensor devices for the detection of VOCs. Experimental The method used for fabricating the

Ammonia gas sensors based on In₂O₃/PANI hetero-nanofibers operating at room temperature

• Qingxin Nie,
• Zengyuan Pang,
• Hangyi Lu,
• Yibing Cai and
• Qufu Wei

Beilstein J. Nanotechnol. 2016, 7, 1312–1321, doi:10.3762/bjnano.7.122

• even death [5][6][7]. So, there is an urgent need to develop a kind of gas sensor with high sensitivity and selectivity to detect NH3 at room temperature. Metal oxide semiconductors can be applied as sensing materials for monitoring NH3. Ammonia sensors based on In2O3 [8], TiO2 [9], SnO2 [10], ZnO [11

• attributed to the p–n junction increases the sensitivity of composite nanofibers sensors. In addition, the sensitivity of the composite gas sensor materials is also connected to the mass ratio of In2O3 and aniline. Because of the smaller amount of polyaniline, which acts as active material in this composite

• system, the In2O3/PANI-1 gas sensor showed a lower sensitivity. However, for the In2O3/PANI-3 gas sensor, the external surface of In2O3 nanofibers was coated with excess polyaniline, yielding a gas sensing perfomance similar to that of pure PANI. Even the response of In2O3/PANI-3 to 100 ppm and 500 ppm

NO gas sensing at room temperature using single titanium oxide nanodot sensors created by atomic force microscopy nanolithography

• Li-Yang Hong and
• Heh-Nan Lin

Beilstein J. Nanotechnol. 2016, 7, 1044–1051, doi:10.3762/bjnano.7.97

• potential application of single metal oxide NDs for gas sensing with a performance that is comparable with that of metal oxide nanowire gas sensors. Keywords: atomic force microscopy nanolithography; photo-activation; photo-recovery; resistive NO gas sensor; titanium oxide nanodot sensor; Introduction In

• ND gas sensor is created. For gas sensing at room temperature, light-assisted approaches, namely the UV-activation and the UV-recovery modes, are utilized. Two ND sensors have been fabricated. For the smaller sensor with a ND size of 80 nm, a response of 31%, a response time of 91 s, and a recovery

• fabrication of a single titanium oxide ND gas sensor. (a) PMMA spin-coated and AFM nanomachining, (b) Ti deposition, (c) PMMA lift-off, (d) photoresist spin-coated, (e) exposure and development, (f) Au deposition, (g) photoresist lift-off, and (h) AFM nano-oxidation. (Adapted from [32]). (a,b) AFM topographic

Evaluation of gas-sensing properties of ZnO nanostructures electrochemically doped with Au nanophases

• Elena Dilonardo,
• Michele Penza,
• Marco Alvisi,
• Cinzia Di Franco,
• Francesco Palmisano,
• Luisa Torsi and
• Nicola Cioffi

Beilstein J. Nanotechnol. 2016, 7, 22–31, doi:10.3762/bjnano.7.3

• gas-sensing properties. Keywords: Au-doped ZnO; chemiresistive gas sensor; electrosynthesis; NO2 gas sensor; ZnO nanostructures; Introduction Today the use of low-cost portable gas sensors is essential to detect and to monitor toxic, polluting and combustible gases for the environmental protection

• strongly depends on MOS morphology and structure, and on the gaseous analyte [4]. The second function transduces the solid–gas interaction into the electrical resistance variation of the gas sensor, correlated to the adsorbed gas concentration to be detected; it is particularly influenced by the

• 120 kV and by a field emission Zeiss ΣIGMA SEM operated at 5–10 kV, 10 μm aperture. Chemiresistive sensor preparation and gas-sensing set-up A scheme of the used chemiresistive ZnO-based gas sensor is shown in Figure 1. After the thermal annealing at 300 or 550 °C for 2 h, pristine and Au-doped ZnO

A simple approach to the synthesis of Cu_1.8S dendrites with thiamine hydrochloride as a sulfur source and structure-directing agent

• Xiaoliang Yan,
• Sha Li,
• Yun-xiang Pan,
• Zhi Yang and
• Xuguang Liu

Beilstein J. Nanotechnol. 2015, 6, 881–885, doi:10.3762/bjnano.6.90

• attention due to its versatile applications in solar cell, electrochemistry, catalysis, and as a gas sensor [1][2][3][4][5]. Many strategies have been developed to prepare Cu1.8S. A solvent-mediated methodology was employed to synthesize highly crystalline Cu1.8S by element copper and sulfur at room

Gas sensing properties of nanocrystalline diamond at room temperature

• Marina Davydova,
• Pavel Kulha,
• Alexandr Laposa,
• Karel Hruska,
• Pavel Demo and
• Alexander Kromka

Beilstein J. Nanotechnol. 2014, 5, 2339–2345, doi:10.3762/bjnano.5.243

• , the three-dimensional model of the current density distribution of the hydrogenated NCD describes the transient flow of electrons between interdigitated electrodes and the hydrogenated NCD surface, that is, the formation of a closed current loop. Keywords: gas sensor; integrator; interdigitated

• sensor sensitivity was strongly dependent on the total surface area. In this study, we demonstrate a gas sensor based on hydrogen (H)-terminated NCD with an integrating measurement principle. The influence of the surface area (adjusted by nucleation time) and the electrode arrangement on the sensitivity

• evidence of the integrator property was observed. Overall, the hydrogenated diamond sensors exhibited a response to each sequence of NH3. These behaviors indicated that the H-terminated NCD sensors were able to accumulate NH3 gas in its water adsorbate layer, which confirms the integrator-type gas sensor

Advances in NO₂ sensing with individual single-walled carbon nanotube transistors

• Kiran Chikkadi,
• Matthias Muoth,
• Cosmin Roman,
• Miroslav Haluska and
• Christofer Hierold

Beilstein J. Nanotechnol. 2014, 5, 2179–2191, doi:10.3762/bjnano.5.227

• employed to evaluate the gas sensor response in SWNT network sensors. Furthermore, there is recent evidence that the electronic nature of the nanotubes (semiconducting or metallic) and the fabrication processes typically used to fabricate these devices play a substantial role in device performance [17] and

• the selectivity of SWNT sensors to NO2 must also be considered. Employing arrays of such individual SWNT sensors may be a viable option for enhancing the selectivity, sensitivity and robustness of SWNT gas sensor products. In this review, we will focus on individual nanotube gas sensors and collate

• individual single-walled carbon nanotubes for NO2 sensing. Review Individual-nanotube transistors for gas sensing The typical individual-SWNT gas sensor is a 3-terminal device, in which the nanotube is contacted by a source and a drain electrode and a current flowing through it is measured. Depending on the

Nanomanipulation and environmental nanotechnology

• Enrico Gnecco,
• Andre Schirmeisen,
• Carlos M. Pina and
• Udo Becker

Beilstein J. Nanotechnol. 2014, 5, 2079–2080, doi:10.3762/bjnano.5.216

• emphasis on their applicability, costs and up-scaling. A novel gas sensor based on ZnO nanoparticles doped with palladium is presented. An invaluable support comes from theory, which in combination with experimental techniques can decisively contribute to a better understanding of important nanoscale

Room temperature, ppb-level NO₂ gas sensing of multiple-networked ZnSe nanowire sensors under UV illumination

• Sunghoon Park,
• Soohyun Kim,
• Wan In Lee,
• Kyoung-Kook Kim and
• Chongmu Lee

Beilstein J. Nanotechnol. 2014, 5, 1836–1841, doi:10.3762/bjnano.5.194

• temperatures. In this study, ZnSe nanowires were synthesized by the thermal evaporation of ZnSe powders and the sensing performance of multiple-networked ZnSe nanowire sensors toward NO2 gas was examined. The results showed that ZnSe might be a promising gas sensor material if it is used at room temperature

• promising candidate as a NO2 gas sensor material. Conclusion ZnSe nanowires exhibited responses towards 50 ppb–5 ppm NO2 ranging from ≈101% to ≈102% and from ≈113% to ≈234% at room temperature in the dark and under UV (365 nm) illumination, respectively. These responses of ZnSe nanowires were stronger than

• the gas sensors fabricated from ZnSe nanowires to 50 ppb, 100 ppb, 500 ppb, 1 ppm and 5 ppm NO2 gas at room temperature (a) in the dark and (b) under UV (365 nm) illumination at 1.2 mW/cm2. (a) Response, (b) response times and (c) recovery times of the multiple-networked ZnSe nanowire gas sensor to

Effects of palladium on the optical and hydrogen sensing characteristics of Pd-doped ZnO nanoparticles

• Anh-Thu Thi Do,
• Hong Thai Giang,
• Thu Thi Do,
• Ngan Quang Pham and
• Giang Truong Ho

Beilstein J. Nanotechnol. 2014, 5, 1261–1267, doi:10.3762/bjnano.5.140

• ability of hydrogen sensors, typical sensors based on ZnO nanoparticles have been designed. The hydrogen gas sensor based on Pd-doped ZnO shows a relative fast response compared with the undoped sample. We also investigated the hydrogen sensing characteristics of these catalytic gas sensors in the

• controls the gas sensing characteristics, have been reported in ZnO films [23]. The sensitivity and selectivity characteristics of the gas sensor are associated with the deep hole-trap states and vacancies on the ZnO surface by the electron transfer mechanism [23][24]. The Pd metal nanoparticles modify the

• nanoscale particle size of 16.2 and 16.5 nm and with a large specific surface area of 37.5 and 34.32 m2/g, respectively, were prepared by wet chemical methods for gas sensor fabrication. The PL spectra at room temperature show that the carrier dynamics coincides with the buildup of the Pd-related green

Template-directed synthesis and characterization of microstructured ceramic Ce/ZrO₂@SiO₂ composite tubes

• Jörg J. Schneider and
• Meike Naumann

Beilstein J. Nanotechnol. 2014, 5, 1152–1159, doi:10.3762/bjnano.5.126

• acid–base and redox properties, which has led to numerous applications in catalysis, energy related studies (e.g., for solid fuel cells), in gas sensor technologies and in biochemistry [1][2][3]. Its high oxygen storage/release capacity is a result of the high reducibility of Ce4+ to Ce3+, which relies

Highly NO₂ sensitive caesium doped graphene oxide conductometric sensors

• Carlo Piloto,
• Marco Notarianni,
• Mahnaz Shafiei,
• Elena Taran,
• Dilini Galpaya,
• Cheng Yan and
• Nunzio Motta

Beilstein J. Nanotechnol. 2014, 5, 1073–1081, doi:10.3762/bjnano.5.120

• Institute for Bioengineering and Nanotechnology, Australian National Fabrication Facility - QLD Node, Brisbane, QLD 4072, Australia 10.3762/bjnano.5.120 Abstract Here we report on the synthesis of caesium doped graphene oxide (GO-Cs) and its application to the development of a novel NO2 gas sensor. The GO

• studied by varying the gas concentration. The developed GO-Cs sensor shows a higher response to NO2 than the pristine GO based sensor due to the oxygen functional groups. The detection limit measured with GO-Cs sensor is ≈90 ppb. Keywords: caesium; conductometric; doping; drop casting; gas sensor

• than 1 ppm; (b) GO-Cs based gas sensor after exposure to different concentrations of NO2 ranging from 0.091 to 1.44 ppm and (c) GO-Cs based sensor during 3 successive cycles of exposure to 0.732 ppm NO2 for 4 min and to dry air for 15 min. Comparison of the GO and GO-Cs response towards NO2 with