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

• morphology of In(NO3)3/PVP, In2O3/PANI composite nanofibers and pure PANI were investigated by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and current–voltage (I–V) measurements. The gas sensing properties

• of these materials towards NH3 vapor (100 to 1000 ppm) were measured at room temperature. The results revealed that the gas sensing abilities of In2O3/PANI composite nanofibers were better than pure PANI. In addition, the mass ratio of In2O3 to aniline and the p–n heterostructure between In2O3 and

• to aniline (0, 1:1, 1:2 and 1:4) were prepared. Correspondingly, the four sensors were denoted as PANI sensor, In2O3/PANI-1 nanofibers sensor, In2O3/PANI-2 nanofibers sensor and In2O3/PANI-3 nanofibers sensor. Structural characterization and gas sensing test The crystal structure of In2O3 nanofibers

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

• Li-Yang Hong Heh-Nan Lin Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan 10.3762/bjnano.7.97 Abstract In this work, the fabrication of single titanium oxide nanodot (ND) resistive sensors for NO gas sensing at room temperature is reported. Two

• atomic force microscopy nanolithography methods, nanomachining and nano-oxidation, are employed. A single titanium nanowire (NW) is created first along with contact electrodes and a single titanium oxide ND is subsequently produced in the NW. Gas sensing is realized by the photo-activation and the photo

• 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

Bacteriorhodopsin–ZnO hybrid as a potential sensing element for low-temperature detection of ethanol vapour

• Saurav Kumar,
• Sudeshna Bagchi,
• Senthil Prasad,
• Anupma Sharma,
• Ritesh Kumar,
• Rishemjit Kaur,
• Jagvir Singh and
• Amol P. Bhondekar

Beilstein J. Nanotechnol. 2016, 7, 501–510, doi:10.3762/bjnano.7.44

• , nanomaterial–biomolecule hybrid gas sensors. Keywords: amphipol; bacteriorhodopsin; bio-hybrid; gas sensing; ITO; ZnO nanostructure; Introduction Nanomaterial–biomolecule conjugates have emerged into one of the most rapidly developing and sought after areas in modern biomolecular device fabrication and

• , SiO2) and polymers (e.g., PVA, gelatine) have been explored for photo–energy conversion, energy storage devices and gas sensing based on photo-conductive activity [12][14][20][21][22]. In parallel, ZnO and its hybrids have evolved as promising structures for sensing and semiconductor applications [23

• sensing material [28]. Further, the advancement in concepts and techniques in nanotechnology resulted in the demonstration of the gas sensing capabilities of ZnO-based nanostructures [29][30]. Recently, researchers have explored innovative hybrid nanostructures based on the interaction of organic and

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

• , respectively. The pristine ZnO and Au@ZnO nanocomposites are proposed as active layer in chemiresistive gas sensors for low-cost processing. Gas-sensing measurements towards NO2 were collected at 300 °C, evaluating not only the Au-doping effect, but also the influence of the different ZnO nanostructures on the

• 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

• active layer in low-cost chemiresistive gas sensors, due to their high sensitivity to gaseous analytes and easy production. The gas-sensing mechanism of MOS-based gas sensors is based on receptor and transducer functions [3]. Specifically, the first regards the recognition of a gaseous analyte by an

Nanostructures for sensors, electronics, energy and environment II

• Nunzio Motta

Beilstein J. Nanotechnol. 2015, 6, 1937–1938, doi:10.3762/bjnano.6.197

• be exploited in room temperature gas sensing devices. The plasmonic effect, generated by the inclusion of metallic nanoparticles, can be used to overcome certain limitations of the carbon materials, especially in organic solar cells [5]. The optical properties of nanomaterials can also be exploited

Atomic scale interface design and characterisation

• Carla Bittencourt,
• Chris Ewels and
• Arkady V. Krasheninnikov

Beilstein J. Nanotechnol. 2015, 6, 1708–1711, doi:10.3762/bjnano.6.174

• their properties [16][17]. Besides dealing with fundamental questions, contributions emphasize possible applications of the remarkable physical and chemical properties of this class of materials such as thermoelectrics [18], plasmonics [19] and gas sensing [20]. In the future, spatial control of doping

Radiation losses in the microwave K_u band in magneto-electric nanocomposites

• Talwinder Kaur,
• Sachin Kumar,
• Jyoti Sharma and
• A. K. Srivastava

Beilstein J. Nanotechnol. 2015, 6, 1700–1707, doi:10.3762/bjnano.6.173

• interesting material with variable properties and a large anisotropy field having a magnetic resonance in the range of 2–52 GHz. Also, at the nano-scale, its optical properties [19], magnetic properties [20][21], piezo-electric properties [22], photocatalytic properties [23], gas-sensing properties [24

Transformations of PTCDA structures on rutile TiO₂ induced by thermal annealing and intermolecular forces

• Szymon Godlewski,
• Jakub S. Prauzner-Bechcicki,
• Thilo Glatzel,
• Ernst Meyer and
• Marek Szymoński

Beilstein J. Nanotechnol. 2015, 6, 1498–1507, doi:10.3762/bjnano.6.155

• example, titanium dioxide surfaces are exceptionally useful in various applications, including the catalysis, solar energy conversion, gas sensing and others [8][9][10][11][12][13][14][15]. Merging two classes of materials, i.e., metal oxide surfaces with organic molecules, seems to be one of the most

Pt- and Pd-decorated MWCNTs for vapour and gas detection at room temperature

• Hamdi Baccar,
• Atef Thamri,
• Pierrick Clément,
• Eduard Llobet and
• Adnane Abdelghani

Beilstein J. Nanotechnol. 2015, 6, 919–927, doi:10.3762/bjnano.6.95

• Nanomatériaux (UR11ES30), Faculté des Sciences de Bizerte, Jarzouna, 7021, Tunisia MINOS-EMaS, Universitat Rovira i Virgili, Avda. Països Catalans 26, 43007 Tarragona, Spain 10.3762/bjnano.6.95 Abstract Here we report on the gas sensing properties of multiwalled carbon nanotubes decorated with sputtered Pt or

• /vapour response of carbon nanotubes, selectivity remains an important challenge that is still far from being achieved. In the quest to improve selectivity, in this paper, we report on the gas sensing properties of carbon nanotubes decorated with sputtered Pt or Pd nanoparticles. Sputtering is an

• used as reported in [40]. Gas sensing measurements The electrical characterisation under gas or vapour environment was performed employing an HP 4192A impedance analyzer [17]. Since all devices showed a resistive behavior at frequencies below 100 kHz, the resistance of the metal-decorated carbon

In situ scanning tunneling microscopy study of Ca-modified rutile TiO₂(110) in bulk water

• Giulia Serrano,
• Beatrice Bonanni,
• Tomasz Kosmala,
• Marco Di Giovannantonio,
• Ulrike Diebold,
• Klaus Wandelt and
• Claudio Goletti

Beilstein J. Nanotechnol. 2015, 6, 438–443, doi:10.3762/bjnano.6.44

• applications ranging from nanotechnology [7] to gas sensing [8], as well as catalysis [9] and biomedicine [10][11]. In particular, the high corrosion resistance of titanium to biological environments has stimulated the study of this metal and its oxide for in vivo or in vitro calcium phosphate ceramic growth

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

• Prague, Czech Republic 10.3762/bjnano.5.243 Abstract This study describes an integrated NH3 sensor based on a hydrogenated nanocrystalline diamond (NCD)-sensitive layer coated on an interdigitated electrode structure. The gas sensing properties of the sensor structure were examined using a reducing gas

• several hours up to several days. Only thermal annealing of the sensor reduces the sensor recovery speed [1][2]. Recently, much attention has been given to solid-state integrating-type (i.e., accumulating- or dosimeter-type) gas sensing devices, which are able to overcome the aforementioned drawbacks [3

• ) and a visible development of diamond nanocrystal faceting. Moreover, the NCD primarily grew on the IDEs as was previously found [9]. The gas-sensing properties of the hydrogenated NCD sensor with a sparse electrode arrangement of 200 µm were tested against a sequence of NH3 pulses (Figure 1b). These

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

• and forests have been shown to be effective for gas sensing, and can be fabricated efficiently on a large scale at low cost. However, the sensing behavior of nanotube networks is very complex due to the large variety of available adsorption sites, the presence of grooves and junctions between

• 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

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

• Department of Nano-Optical Engineering, Korea Polytechnic University, 2121 Jeongwang-dong, Shiheung city, Gyeonggi-do, 429-793, Republic of Korea 10.3762/bjnano.5.194 Abstract Reports of the gas sensing properties of ZnSe are few, presumably because of the decomposition and oxidation of ZnSe at high

• diodes [5] and UV photodetectors [6]. On the other hand, there are almost no reports on the gas sensing properties of ZnSe. This might be due to the decomposition and oxidation of ZnSe at temperatures above 200 °C [7] and a lack of good sensing performance at room temperature. In recent years, one

• enhance the sensing performance of ZnSe, 1D nanostructure-based sensors at room temperature. In this study, multiple-networked ZnSe nanowire sensors were fabricated and examined for their room-temperature, NO2-gas sensing properties under UV illumination. Unlike individual 1D nanostructure sensors

Experimental techniques for the characterization of carbon nanoparticles – a brief overview

• Wojciech Kempiński,
• Szymon Łoś,
• Mateusz Kempiński and
• Damian Markowski

Beilstein J. Nanotechnol. 2014, 5, 1760–1766, doi:10.3762/bjnano.5.186

• carrier transport within the systems of CNs by varying the temperature, adsorbed molecules and external electric field. Due to the significant changes in resistivity induced by the host–guest interactions, the systems of CNs might prove interesting in the fields of gas sensing, molecular electronics or

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

• the gas sensing response characteristics allows us to suggest that the dissociation of hydrogen takes place at PdZn-vacancies ([Pd 2+(4d9)]). The design of this sensor allows for a continuous monitoring in the range of 0–100% LEL H2 concentration with high sensitivity and selectivity. Keywords

• hydrogen sensing [1][2][3][4][5][6]. The key features and availability of ZnO nanocrystals in distributed discrete gas sensing devices crucially depend on the growth conditions. These conditions strongly influence their size, uniformity and defects. Optical properties and gas sensing characteristics in ZnO

• ], compatibility with other nanodevices, and are potentially the best gas sensors. Oxides cannot easily distinguish between different types of gases, but the addition of certain noble metals as dopants can promote the gas-sensing performance [9][10][11]. Noble metal dopants in ZnO can modify the optical and

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

• and environmental monitoring [12]. Theoretical [13][14] and experimental [15][16][17][18][19] studies have revealed that functionalization of graphene can improve significantly its gas sensing performance [20]. The presence of dopants or defects in the graphene lattice can increase the adsorption

• groups can be easily controlled [28][34][35][36][37][38] making this process a good candidate for graphene functionalization. The oxygen groups of the resulting GO lead to the disruption of the graphitic structure, thus making the material electrically too much insulating for resistive gas sensing

• applications. However, the partial removal of oxygen groups, leading to reduced GO can be achieved by chemical [38][39], thermal [40][41] or ultraviolet-assisted process [42]. The conductivity and gas sensing performance of the reduced GO is comparable or superior to that of the pristine graphene [43], due to

Gas sensing with gold-decorated vertically aligned carbon nanotubes

• Prasantha R. Mudimela,
• Mattia Scardamaglia,
• Oriol González-León,
• Nicolas Reckinger,
• Rony Snyders,
• Eduard Llobet,
• Carla Bittencourt and
• Jean-François Colomer

Beilstein J. Nanotechnol. 2014, 5, 910–918, doi:10.3762/bjnano.5.104

• , regardless of the nanotube length. Keywords: alignment; carbon nanotubes; decoration; gas sensors; metal nanoparticles; thermal CVD; Introduction The interest in gas sensing for reaching a widespread, continuous pollution detection and control has been growing steadily in the last decades due to the

• based on nanomaterials have been developed to fabricate small and inexpensive gas sensors with high sensitivity and able to work at room temperature [1]. Among the possible active materials in gas sensing devices, good candidates are carbon nanotubes (CNTs), thanks to their intrinsic properties such as

• room temperature), prompt response, short recovery time and reasonable reversibility and stability [2][3][4][6]. A further advance in the development of CNT gas sensing devices was the use of vertically aligned CNTs (VA-CNTs). In this case the sensing device benefits from the unidirectional electrical

In situ growth optimization in focused electron-beam induced deposition

• Paul M. Weirich,
• Marcel Winhold,
• Christian H. Schwalb and
• Michael Huth

Beilstein J. Nanotechnol. 2013, 4, 919–926, doi:10.3762/bjnano.4.103

• are used in highly miniaturized magnetic field [1][2], strain/force [3][4] and gas sensing [5] applications, as well as in micromagnetic studies on domain wall nucleation and propagation [6][7]. On the basis of the in situ, electron irradiation-induced tunability of metallic FEBID-structures

Plasmonics-based detection of H₂ and CO: discrimination between reducing gases facilitated by material control

• Gnanaprakash Dharmalingam,
• Nicholas A. Joy,
• Benjamin Grisafe and
• Michael A. Carpenter

Beilstein J. Nanotechnol. 2012, 3, 712–721, doi:10.3762/bjnano.3.81

• , and particularly for plasmonics-based gas sensing. The extremely high sensitivity of the plasmon resonance peak to changes in the free-electron density of gold nanoparticles or a change in the dielectric function of the metal-oxide host material due to adsorbate reactions on surfaces makes this a

• through studies using infra-red spectroscopy [26]. A significant difference between this previous study and practical studies of emission-gas sensing is that the measurements were not done in the presence of background oxygen. However, if H2 were to react in the presence of an oxygen background, (such as

Zeolites as nanoporous, gas-sensitive materials for in situ monitoring of DeNO_x-SCR

• Thomas Simons and
• Ulrich Simon

Beilstein J. Nanotechnol. 2012, 3, 667–673, doi:10.3762/bjnano.3.76

• elementary catalytic process promoting a full description of the NH3-SCR reaction system. Keywords: DeNOx-SCR; gas sensing; in situ; impedance spectroscopy; zeolite; Introduction Zeolites are crystalline, nanoporous aluminosilicates composed of [TO4] tetrahedra (T = Si, Al). In H-form zeolites protons

• sensitivity and catalytic activity renders zeolites as interesting materials for the study of the correlation of gas-sensing and catalytic properties in situ. This is of fundamental academic and technological interest, as it will potentially afford knowledge about the elementary reaction mechanisms [27]. For

Distribution of functional groups in periodic mesoporous organosilica materials studied by small-angle neutron scattering with in situ adsorption of nitrogen

• Monir Sharifi,
• Dirk Wallacher and
• Michael Wark

Beilstein J. Nanotechnol. 2012, 3, 428–437, doi:10.3762/bjnano.3.49

• and hence a variety of reactions are possible for the further modification of the PMO with a large array of desired groups. This expands the range of applications in, for example, optical gas sensing, catalysis, chromatography, separation and nanotechnology [9]. As is typical for mesoporous materials

Conducting composite materials from the biopolymer kappa-carrageenan and carbon nanotubes

• Ali Aldalbahi,
• Jin Chu,
• Peter Feng and
• Marc in het Panhuis

Beilstein J. Nanotechnol. 2012, 3, 415–427, doi:10.3762/bjnano.3.48

• these CNTs. The electrical and mechanical characteristics of free-standing composite films prepared by evaporative casting and vacuum filtration were assessed, including the effect of incorporating the plasticizer glycerin. The gas-sensing ability of these composite films is demonstrated. Results and

Functionalised zinc oxide nanowire gas sensors: Enhanced NO₂ gas sensor response by chemical modification of nanowire surfaces

• Eric R. Waclawik,
• Jin Chang,
• Andrea Ponzoni,
• Isabella Concina,
• Dario Zappa,
• Elisabetta Comini,
• Nunzio Motta,
• Guido Faglia and
• Giorgio Sberveglieri

Beilstein J. Nanotechnol. 2012, 3, 368–377, doi:10.3762/bjnano.3.43

• innovations in the semiconductor gas-sensing field are still in demand [1][2][3]. Impedance-semiconductor gas sensors typically operate at temperatures greater than 200 °C [4][5]. High operating temperatures are generally required to maximise the sensor response to target gases, either to activate the

• nanostructured forms, such as nanowires, nanoribbons, nanobelts and as tetrapods [11], and their potential use in NO2 gas sensing in these forms is well known [12][13]. In this study we investigated the effects that two very different types of organic ligands imposed on the sensitivity and response of

• ultrahigh vacuum rather than in dry air. Taking the TG results into account, a sensor operating temperature of 190 °C was chosen for all gas-response tests. Gas sensing measurements for the various ZnO samples with different morphologies and compositions were performed for the gases ammonia, nitrous oxide

Investigation on structural, thermal, optical and sensing properties of meta-stable hexagonal MoO₃ nanocrystals of one dimensional structure

• Angamuthuraj Chithambararaj and
• Arumugam Chandra Bose

Beilstein J. Nanotechnol. 2011, 2, 585–592, doi:10.3762/bjnano.2.62

• counts/ppm for λmax = 684, 764 and 935 nm, respectively. From the plot, the maximum sensitivity is seen for λmax = 684 nm. Here, it is proposed that the gas sensing mechanism follows the changes in the refractive index and evanescent wave absorption. For h-MoO3, the oxygen vacancies and interstitial

• molybdenum atoms play a major role in gas sensing operation. The reaction between ethanol gas and the chemisorbed oxygen (O2−, O− and O2−) at the surface of the MoO3 material changes the refractive index of the clad structure. Due to this change, the light wave travelling through the removed and coated

• linearly as a function of ethanol concentration in the range of 0 to 500 ppm. In the present study, changes in the refractive index and the evanescent wave absorption phenomenon were proposed to explain the gas sensing mechanism. The reaction between ethanol gas and the chemisorbed oxygen (O2−, O− and O2