Humidity-dependent electrical performance of CuO nanowire networks studied by electrochemical impedance spectroscopy

• Jelena Kosmaca,
• Juris Katkevics,
• Jana Andzane,
• Raitis Sondors,
• Liga Jasulaneca,
• Raimonds Meija,
• Kiryl Niherysh,
• Yelyzaveta Rublova and
• Donats Erts

Beilstein J. Nanotechnol. 2023, 14, 683–691, doi:10.3762/bjnano.14.54

• contribution from resistance, capacitance, constant phase element, and Warburg element to the total impedance at various RH. Physical models describing the impact of chemisorption and physisorption processes are proposed to clarify the observed changes in the impedance spectra, discuss gas sensing mechanisms

A mid-infrared focusing grating coupler with a single circular arc element based on germanium on silicon

• Xiaojun Zhu,
• Shuai Li,
• Ang Sun,
• Yongquan Pan,
• Wen Liu,
• Yue Wu,
• Guoan Zhang and
• Yuechun Shi

Beilstein J. Nanotechnol. 2023, 14, 478–484, doi:10.3762/bjnano.14.38

• sensors is of great significance. In 2015, Bai et al. reported a flexible healable transparent chemical gas sensing device that exhibited robust flexibility, good transparency, and reliable water-enabled healability of the gas sensing performance at room temperature [15]. Wang proposed a flexible

Enhanced electronic transport properties of Te roll-like nanostructures

• E. R. Viana,
• N. Cifuentes and
• J. C. González

Beilstein J. Nanotechnol. 2022, 13, 1284–1291, doi:10.3762/bjnano.13.106

• Earth’s crust and a well-known p-type and narrow-bandgap (≈0.35 eV at room temperature) semiconductor material. Tellurium is widely used in thermoelectric devices, piezoelectric devices, photoconductive devices, gas sensing, nonlinear optical devices, solar cells, photonic crystals, holographic recording

• ) = 881 cm2/V·s) in these nanostructures. Thermoelectric devices, piezoelectric devices, photoconductive devices, gas sensing, solar cells, and field-effect transistors would have better performance if the mobility of charge carriers in the active region of the devices was greater. In addition, the low

Modeling a multiple-chain emeraldine gas sensor for NH₃ and NO₂ detection

• Hana Sustkova and
• Jan Voves

Beilstein J. Nanotechnol. 2022, 13, 721–729, doi:10.3762/bjnano.13.64

• Hana Sustkova Jan Voves Faculty of Electrical Engineering, Czech Technical University in Prague, Technicka 2, Prague 6, Czech Republic 10.3762/bjnano.13.64 Abstract This paper describes atomistic device models of a multiple-chain polyaniline (PANI) gas sensing component, utilizing the non

• it shows a resistance change when gas molecules are in the vicinity of the chain. Interesting for this application could be the detection of NH3 or NO2 [5]. Mechanism of Gas Sensing When gas molecules interact with the PANI chain, the resistance of the bulk material changes. For example, ammonia gas

A chemiresistive sensor array based on polyaniline nanocomposites and machine learning classification

• Jiri Kroutil,
• Alexandr Laposa,
• Ali Ahmad,
• Jan Voves,
• Vojtech Povolny,
• Ladislav Klimsa,
• Marina Davydova and
• Miroslav Husak

Beilstein J. Nanotechnol. 2022, 13, 411–423, doi:10.3762/bjnano.13.34

• powerful tool to address the abovementioned drawbacks is the implementation of a multisensor array combined with appropriate pattern recognition and classification tools [6]. Recently, classification in gas sensing applications has been carried out by principal component analysis to identify the difference

• been used for the classification of gas sensor data using a 10-fold cross-validation to reach the highest classification rate. Results and Discussion The sensors layers were investigated by scanning electron microcopy (SEM), Raman spectroscopy, current–voltage and temperature analysis, and gas sensing

• coefficient. The resistivity of these nanocomposites depends on the p–n depletion layer width on the interface between the n-type nanoparticles and the surrounding p-type PANi molecules. Gas sensing analysis The gas sensing characterizations of sensitive layers were performed using a custom-built apparatus

Tin dioxide nanomaterial-based photocatalysts for nitrogen oxide oxidation: a review

• Viet Van Pham,
• Hong-Huy Tran,
• Thao Kim Truong and
• Thi Minh Cao

Beilstein J. Nanotechnol. 2022, 13, 96–113, doi:10.3762/bjnano.13.7

• vacancy defects (OVs) [15][16]. Therefore, SnO2 is considered a potential material in various technological fields such as catalysis, optoelectronic devices, rechargeable lithium batteries, electrocatalysis, photocatalysis, solar energy conversion, and gas sensing [17][18][19][20][21][22][23][24]. In the

• photocatalysts and a cost-effective, environmentally benign way through heat treatment in different atmospheres [39]. Combining noble metals with SnO2, such as in Au/SnO2 [78] or Pd/SnO2 [79], is an advanced approach yielding an effective performance for gas sensing. However, There is only one report by Bui et

Morphology-driven gas sensing by fabricated fractals: A review

• Vishal Kamathe and
• Rupali Nagar

Beilstein J. Nanotechnol. 2021, 12, 1187–1208, doi:10.3762/bjnano.12.88

• to be possessing better gas sensing capabilities. Fab-fracs with these salient features will help in designing the commercial gas sensors with better performance. Keywords: adsorption sites; fabricated fractal; fractal dimension; gas sensor; morphology; pore network; recovery time; response time

• usage [5][6][7]. The objectives in gas sensing research are usually set to enhance the sensitivity (how the sensor responds to small changes when the gas environment around it changes), selectivity (if a sensor can still respond to a particular gas when many gases present), stability (how the sensor

• gas sensors exist [26][30][31]. Although there are numerous reviews on gas sensing [7][29][32][33][34][35][36][37][38], reviews on fabricated fractal (fab-frac)-based gas sensors have not been addressed to the best of our knowledge. In this review, diverse fractal structures used in gas sensing

A Au/CuNiCoS₄/p-Si photodiode: electrical and morphological characterization

• Adem Koçyiğit,
• Adem Sarılmaz,
• Teoman Öztürk,
• Faruk Ozel and
• Murat Yıldırım

Beilstein J. Nanotechnol. 2021, 12, 984–994, doi:10.3762/bjnano.12.74

• great attention due their unique electronic, magnetic, optical, and gas sensing properties. Spinel compounds can be employed in data storage applications, lithium-ion batteries, gas sensors, and medical diagnostics [1][2]. Spinels have a cubic crystal structure with the general chemical formula AB2X4

Simulation of gas sensing with a triboelectric nanogenerator

• Kaiqin Zhao,
• Hua Gan,
• Huan Li,
• Ziyu Liu and
• Zhiyuan Zhu

Beilstein J. Nanotechnol. 2021, 12, 507–516, doi:10.3762/bjnano.12.41

• applied for gas sensing without external power supply. In this paper, a two-dimensional model of a TENG was established, and a gas jet a rectangular cross section was added between two triboelectric materials. The TENG could generate distinguishable electrical signals according to the different types of

• gas and the different gas injection areas. This work contributes to the area of self-powered gas sensing. Keywords: gas; sensor; triboelectric nanogenerator (TENG); Introduction With economic development and social progress, there is an increasing demand for wearable [1][2][3][4], medical [5], and

Nickel nanoparticle-decorated reduced graphene oxide/WO₃ nanocomposite – a promising candidate for gas sensing

• Ilka Simon,
• Alexandr Savitsky,
• Rolf Mülhaupt,
• Vladimir Pankov and
• Christoph Janiak

Beilstein J. Nanotechnol. 2021, 12, 343–353, doi:10.3762/bjnano.12.28

• /WO3 composite and CO gas, a response time (Tres) of 7 min and a recovery time (Trec) of 2 min was determined. Keywords: gas sensing; magnetic measurements; nickel nanoparticles; reduced graphene oxide; tungsten oxide; Introduction Toxic gases as well as volatile organic compounds (VOC) are known air

• recovery rate. Also, it should work at low cost and with low power consumption [3]. In comparison to conventional gas sensors, nanostructure-based gas sensors are more sensitive because of their increased detection area [4]. The most common mode used in gas sensing is the resistance mode, where the change

• 200 to 400 °C, which means a high power consumption [4]. WO3 is a wide-bandgap [12][13] n-type semiconductor [14][15] with good sensitivity towards NO2 [16] and CO [17]. Known successful routes to improve the MOS gas sensing performance are doping with transition metals, decoration with noble metals

Selective detection of complex gas mixtures using point contacts: concept, method and tools

• Alexander P. Pospelov,
• Victor I. Belan,
• Dmytro O. Harbuz,
• Volodymyr L. Vakula,
• Lyudmila V. Kamarchuk,
• Yuliya V. Volkova and
• Gennadii V. Kamarchuk

Beilstein J. Nanotechnol. 2020, 11, 1631–1643, doi:10.3762/bjnano.11.146

• the sensing element. A condensate film formed on the gas-sensing surface switches on the autonomous power supply of the sensing element, enabling the observation and measurement of the dynamics of resistance variation during the exposure and relaxation periods. This is due to the fact that, in the

• molecule, the molecule can be characterized by a certain energy of interaction with the gas-sensing matrix material (i.e., the adsorption energy). Any adsorption event in the Yanson point contact entails a redistribution of the electron density in the conduction channel of the point contact, the scattering

Gas-sensing features of nanostructured tellurium thin films

• Dumitru Tsiulyanu

Beilstein J. Nanotechnol. 2020, 11, 1010–1018, doi:10.3762/bjnano.11.85

• Dumitru Tsiulyanu CIMAN Research Centre of Department of Physics, Technical University, bul. Dacia 41, MD-2060 Chisinau, Moldova 10.3762/bjnano.11.85 Abstract Nanocrystalline and amorphous nanostructured tellurium (Te) thin films were grown and their gas-sensing properties were investigated at

• were interpreted in terms of an increase in disorder (amorphization), leading to an increase in the surface chemical activity of chalcogenides, as well as an increase in the active surface area due to substrate porosity. Keywords: gas-sensing properties; NO2; tellurium thin films; nanocrystalline

• development of thin films in chemical-sensing applications, especially for toxic gas sensing. Szaro [4] pioneered the studies regarding the effects of oxygen and nitrogen, diluted in either dry or wet air, on the electrical properties of Te films. The results showed an increase in the hole concentration

Formation of nanoripples on ZnO flat substrates and nanorods by gas cluster ion bombardment

• Xiaomei Zeng,
• Vasiliy Pelenovich,
• Bin Xing,
• Rakhim Rakhimov,
• Wenbin Zuo,
• Alexander Tolstogouzov,
• Chuansheng Liu,
• Dejun Fu and
• Xiangheng Xiao

Beilstein J. Nanotechnol. 2020, 11, 383–390, doi:10.3762/bjnano.11.29

• discussed. The results obtained in this study are of interest in the application of ZnO nanostructures for, e.g., gas sensing, solar cells, or field emitters, where controlled surface morphologies are required. Experimental We have grown ZnO nanorods on Si(100) substrates (HF-Kejing Materials Technology Co

Synthesis and acetone sensing properties of ZnFe₂O₄/rGO gas sensors

• Kaidi Wu,
• Yifan Luo,
• Ying Li and
• Chao Zhang

Beilstein J. Nanotechnol. 2019, 10, 2516–2526, doi:10.3762/bjnano.10.242

• about 600–1000 nm. The gas sensing test revealed that the introduction of rGO improved the performance of the sensing of acetone to low concentration, and the ZnFe2O4/rGO composite gas sensor containing 0.5 wt % of rGO exhibited a high sensitivity in sensing test using 0.8–100 ppm acetone at 200 °C. The

• amounts of acetone still need to be enhanced. As a dual metal oxide, AB2O4 spinel materials received much attention in the field of gas sensing [13][14]. With a unique spinel structure and a narrow bandgap width (≈1.94 eV), zinc ferrite (ZnFe2O4) has remarkable properties and shows good potential in the

• field of gas sensing. It was reported that small, well-dispersed ZnFe2O4 nanoparticles showed a good selectivity to acetone at 200 °C, but the detection limit was only 5 ppm [15]. Porous ZnFe2O4 double-shell microspheres showed a response to acetone at 206 °C, which is mainly ascribed to their unique

High-temperature resistive gas sensors based on ZnO/SiC nanocomposites

• Vadim B. Platonov,
• Marina N. Rumyantseva,
• Alexander S. Frolov,
• Alexey D. Yapryntsev and
• Alexander M. Gaskov

Beilstein J. Nanotechnol. 2019, 10, 1537–1547, doi:10.3762/bjnano.10.151

• (XPS). The electrophysical and gas sensing properties of the materials were investigated by in situ conductivity measurements in the presence of the reducing gases CO and NH3 (20 ppm), in dry conditions (relative humidity at 25 °C RH25 = 0) and in humid air (RH25 = 30%) in the temperature range 400–550

Selective gas detection using Mn₃O₄/WO₃ composites as a sensing layer

• Yongjiao Sun,
• Zhichao Yu,
• Wenda Wang,
• Pengwei Li,
• Gang Li,
• Wendong Zhang,
• Lin Chen,
• Serge Zhuivkov and
• Jie Hu

Beilstein J. Nanotechnol. 2019, 10, 1423–1433, doi:10.3762/bjnano.10.140

• Abstract Pure WO3 sensors and Mn3O4/WO3 composite sensors with different Mn concentrations (1 atom %, 3 atom % and 5 atom %) were successfully prepared through a facile hydrothermal method. As gas sensing materials, their sensing performance at different temperatures was systematically investigated for gas

• detection. The devices displayed different sensing responses toward different gases at specific temperatures. The gas sensing performance of Mn3O4/WO3 composites (especially at 3 atom % Mn) were far improved compared to sensors based on pure WO3, where the improvement is related to the heterojunction formed

• door for potential applications in gas recognition and detection. Keywords: Mn3O4/WO3 composites; heterojunctions; working temperature; gas sensing; selectivity; Introduction Tungsten oxide (WO3) is a highly stable, classical transition metal oxide. When synthesized, WO3 usually presents a yellowish

Gas sensing properties of individual SnO₂ nanowires and SnO₂ sol–gel nanocomposites

• Alexey V. Shaposhnik,
• Dmitry A. Shaposhnik,
• Sergey Yu. Turishchev,
• Olga A. Chuvenkova,
• Stanislav V. Ryabtsev,
• Alexey A. Vasiliev,
• Xavier Vilanova,
• Francisco Hernandez-Ramirez and
• Joan R. Morante

Beilstein J. Nanotechnol. 2019, 10, 1380–1390, doi:10.3762/bjnano.10.136

• selectivity to target gases. The aim of this work is the comparison of gas sensing properties of tin dioxide in the form of individual nanowires and nanopowders obtained by sol–gel synthesis. This comparison is necessary because the traditional synthesis procedures of small particle, metal oxide materials

• surface-to-volume ratio of gas sensing materials an important parameter in determining their gas sensitivity. Traditionally, quasi-0-dimensional (i.e., spherical) nano-objects have been used in order to create highly porous materials. In gas sensors, agglomerates of nanoparticles with a high specific area

• platinum, following a process described elsewhere (Figure 3) [29]. The electrical measurements were performed using a Keithley 2400 source meter unit (SMU). For gas sensing experiments, the devices were placed in a Linkam chamber with an integrated heater; the gas flow (≥99.999% purity) was regulated by

Hydrophilicity and carbon chain length effects on the gas sensing properties of chemoresistive, self-assembled monolayer carbon nanotube sensors

• Juan Casanova-Cháfer,
• Carla Bittencourt and
• Eduard Llobet

Beilstein J. Nanotechnol. 2019, 10, 565–577, doi:10.3762/bjnano.10.58

• chain and its hydrophilicity on the gas sensing properties of SAMs formed on carbon nanotubes are studied, and additionally, the gas sensing mechanisms are discussed. Four thiols differing in the length of the carbon chain and in the hydrophobic or hydrophilic nature of the head functional group are

• response and selectivity. This would make the detection of polar and nonpolar gas species employing low-power gas sensors easier, even under fluctuating ambient moisture conditions. Keywords: carbon length chain; gas sensing mechanism; hydrophilicity; hydrophobicity; multiwall carbon nanotubes (MWCNTs

• , pristine carbon nanotubes (CNTs) present some limitations for gas sensing. For example, carbon nanotube gas sensors often suffer from slow recovery, especially when operated at room temperature, which eventually results in baseline and response drift. For that reason, it is usually necessary to heat up the

Advanced scanning probe lithography using anatase-to-rutile transition to create localized TiO₂ nanorods

• Julian Kalb,
• Vanessa Knittel and
• Lukas Schmidt-Mende

Beilstein J. Nanotechnol. 2019, 10, 412–418, doi:10.3762/bjnano.10.40

• optoelectronic characteristics. The fabrication of nanostructured TiO2 is inexpensive and hence employed in many applications such as photodetectors [2], photovoltaics [3][4][5][6], photocatalysis [7][8][9][10][11], surficial disinfection [12], biosensing [13], gas sensing [14][15][16], dewetting [17][18][19

Sub-wavelength waveguide properties of 1D and surface-functionalized SnO₂ nanostructures of various morphologies

• Venkataramana Bonu,
• Binaya Kumar Sahu,
• Arindam Das,
• Sankarakumar Amirthapandian,
• Sandip Dhara and
• Harish C. Barshilia

Beilstein J. Nanotechnol. 2019, 10, 379–388, doi:10.3762/bjnano.10.37

• nanoparticles [18] have been reported in our previous studies. We have also deciphered strong correlations of various defects in SnO2 NSs for chemical gas sensing [13] and wettability properties [19]. The growth of metal oxides with controllable dimensions is an important area for technological applications. In

Wet chemistry route for the decoration of carbon nanotubes with iron oxide nanoparticles for gas sensing

• Hussam M. Elnabawy,
• Juan Casanova-Chafer,
• Badawi Anis,
• Mostafa Fedawy,
• Mattia Scardamaglia,
• Carla Bittencourt,
• Ahmed S. G. Khalil,
• Eduard Llobet and
• Xavier Vilanova

Beilstein J. Nanotechnol. 2019, 10, 105–118, doi:10.3762/bjnano.10.10

• by selecting the appropriate ratio of carbon nanotubes/iron salt, while nanoparticle size can be modulated by controlling the calcination period. Pristine and iron-decorated carbon nanotubes were deposited on silicon substrates to investigate their gas sensing properties. It was found that loading

• with iron oxide nanoparticles substantially ameliorated the response towards nitrogen dioxide. Keywords: benzene detection; doping; gas sensor; metal nanoparticle decoration; multiwalled carbon nanotubes; NO2 detection; room temperature gas sensing; surface modification; Introduction Carbon nanotubes

• properties [2][3]. In particular, they have been extensively researched in gas sensing applications because of their high thermal and chemical stability, high adsorption capacity and suitability for being functionalized, which enables tailoring (to some extent) their sensitivity and selectivity to the

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

• semiconductors (MOS) are widely used as materials for gas sensing. Usually, MOS gas sensors have some common shortages, such as relatively poor selectivity and high operating temperature. Graphene has drawn much attention as a gas sensing material in recent years because it can even work at room temperature

• easily affected by the adsorption of gas molecules at room temperature. Thus, graphene has a promising future in the application in gas sensors. Schedin et al. [2] studied the gas sensing performance of graphene for the first time in 2007 and claimed that the adsorption of gas molecules caused a gradual

• of MOS gas sensors. Modifications of composition and surface, and light illumination of MOS are effective ways to improve their gas-sensing performance. MOS composites with graphene or its derivatives can reduce the operating temperature and yield outstanding sensing performance surpassing that of

Improved catalytic combustion of methane using CuO nanobelts with predominantly (001) surfaces

• Qingquan Kong,
• Yichun Yin,
• Bing Xue,
• Yonggang Jin,
• Wei Feng,
• Zhi-Gang Chen,
• Shi Su and
• Chenghua Sun

Beilstein J. Nanotechnol. 2018, 9, 2526–2532, doi:10.3762/bjnano.9.235

• shows high reactivity due to the high ratio of lowly coordinated oxygen – a feature that has been employed for gas sensing and Li-ion batteries [21]. Now we turn to the experimental validation, starting with the synthesis of CuO nanowires (NWs) and CuO nanobelts (NBs) comprised of predominantly (001

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

• , Hawthorn, VIC 3122, Australia 10.3762/bjnano.9.202 Abstract Electrospun one-dimensional (1D) nanostructures are rapidly emerging as key enabling components in gas sensing due to their unique electrical, optical, magnetic, thermal, mechanical and chemical properties. 1D nanostructures have found

• 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

• integration flexibility. To date, many different gas sensing technologies have been developed. The predominant approaches to utilization are based on changes in the electrical conductance, optical properties, electrochemical potential or resonant frequency of the device [12][13][14][15][16][17][18][19][20][21

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

• ]. Besides, the corresponding binding position and energy of NO adsorbed on single-layer MoS2 [23] and WS2 [28] were analyzed from a theoretical point of view. Even though the gas-sensing properties involving NO and NO2 are well studied, few studies [29] have been carried out to explore the difference in

• spin-polarized gas-sensing between NO and other gas molecules. A completely spin-polarized current flow can be achieved in a half-metallic material [30][31][32][33]. Half-metallic materials exhibit semiconducting behavior in one spin channel and metallic behavior in the opposite spin channel, which

• , 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