- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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[Polymers and Polymeric Composites: A Reference Series] Functional Polymers || Conducting Polymer Nanocomposites as Gas Sensors
摘要： The great concerns regarding environmental and living beings protection together with the widespread requirements for highly accurate process monitoring have highlighted the need for the development of new and sensitive sensors. Conducting polymers and their nanocomposites have been used widely as sensing materials owing to their special redox chemistry. The electrical properties can be controlled easily by doping and undoping processes resulting into the generation of conducting and nonconducting states, respectively. The electrical conductivity also depends on the type and amount of filler (nanosize filler in some cases) used which produces the positive or negative carriers responsible for the conduction. Any type of interaction of these polymers that affects the number and movement of charge carriers affects the conductivity and is the main principle behind the gas sensing characteristics. Advances in nanotechnology allows for the fabrication of various conducting polymer nanocomposites using different techniques. Conducting polymer nanocomposites have high surface area, small dimension, and show enhanced properties, making them suitable for various sensor devices. This chapter presents the different types of gas sensors based on the conducting polymer (polyaniline, polypyrrole, and polythiophene)-based nanocomposites, their progress, and future scope of ongoing research in this research area. The factors that affect the performance of the gas sensors and the chemistry of the sensing process are also addressed.
关键词： Conducting polymers,Undoping,Doping,Polythiophene,Environmental conditions,Polypyrrole,Surface area,Nanocomposites,Polyaniline,Gas sensors
更新于2025-09-10 09:29:36
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Cerium Oxide-Tungsten Oxide Core-Shell Nanowire-Based Microsensors Sensitive to Acetone
摘要： Gas sensitive cerium oxide-tungsten oxide core-shell nanowires are synthesized and integrated directly into micromachined platforms via aerosol assisted chemical vapor deposition. Tests to various volatile organic compounds (acetone, ethanol, and toluene) involved in early disease diagnosis demonstrate enhanced sensitivity to acetone for the core-shell structures in contrast to the non-modified materials (i.e., only tungsten oxide or cerium oxide). This is attributed to the high density of oxygen vacancy defects at the shell, as well as the formation of heterojunctions at the core-shell interface, which provide the modified nanowires with ‘extra’ chemical and electronic sensitization as compared to the non-modified materials.
关键词： metal oxides,acetone,gas sensors,heterojunctions,volatile organic compounds (VOCs)
更新于2025-09-10 09:29:36
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Sensing of Acetone by Al-doped ZnO
摘要： The development of chemoresistive gas sensors for environmental and industrial air monitoring as well as medical breath analysis is investigated. Flame-made ZnO nanoparticles (NPs) doped with 1 at% Aluminum exhibited higher sensing performance (response 245, response time ~ 3 s, and sensitivity 23 ppm-1) than pure ZnO and those made by a hydrothermal method (HT) (56, ~ 12 s, and 4 ppm-1) for detection of 10 ppm acetone. Furthermore, their sensing response of ~10 to 0.1 ppm of acetone at 90% RH is superior to other metal oxide sensors and they feature good acetone selectivity to other compounds (including NH3, isoprene and CO). Characterization by N2 adsorption, X-ray photoelectron and UV-vis spectroscopies reveals that the improved sensing performance of flame-made Al-doped ZnO NPs is associated primarily to a higher density of oxygen vacancies than pure ZnO and all HT-made NPs. This leads to a greater number of adsorbed oxygen ions on the surfaces of Al-doped ZnO NPs, which can react with acetone molecules.
关键词： nanoparticles,flame spray pyrolysis,Al-doped ZnO,acetone,gas sensors
更新于2025-09-10 09:29:36
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Gallium Oxide || Ga2O3-based gas sensors
摘要： β-Ga2O3 has recently gained a lot of interest for applications in solar-blind deep ultraviolet (UV) detectors and high-power electronics at elevated temperatures. The interest stems from its intrinsic material properties, such as wide-bandgap nature (4.9 eV) and high breakdown electric field. β-Ga2O3 can also serve as a reactive oxide layer, sensitive to a wide variety of gases, especially at high temperatures in harsh environments. Many β-Ga2O3-based gas sensors have been reported recently [1–20]. In this chapter, the gas sensing mechanism and the sensing characteristics of β-Ga2O3 are reviewed. First, the material properties of β-Ga2O3 are reviewed for a clear understanding of surface reactions at oxide surfaces with various gas molecules. The crystal structure of β-Ga2O3 and the surface atomic configurations of 201 and (010)-oriented β-Ga2O3 are investigated. The wet and dry etching characteristics and the metal contact properties of 201 and (010) β-Ga2O3 single crystals are discussed for a broad range of device applications. Recent reports of β-Ga2O3-based hydrogen sensors are discussed, and the hydrogen sensing properties of 201 and (010) β-Ga2O3 single crystals are compared for enhanced hydrogen detection.
关键词： crystal structure,β-Ga2O3,high-temperature applications,wet and dry etching,Ohmic contact,gas sensors,hydrogen sensors
更新于2025-09-09 09:28:46
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A New Method to Prepare Few-Layers of Nanoclusters Decorated Graphene: Nb2O5/Graphene and Its Gas Sensing Properties
摘要： During the last decade, due to its excellent electrical, mechanical and thermal properties of chemically modified graphene has been extensively studied for many applications, such as polymer composites, energy-related materials, biomedical applications and sensors. The aim of this work is to evaluate the gas sensing performance of niobium oxide (Nb2O5) nanoclusters deposited onto few-layers graphene powder by magneton sputtering. Two different samples were prepared by changing electrical power of deposition. The materials were deeply morphologically, structurally and chemically characterized. Finally, they were deposited onto alumina substrates and their sensing properties were investigated vs. different gases, showing good sensing performance vs. ppm concentrations of NO2 at room temperature.
关键词： NO2 detection,room temperature,chemoresistive gas sensors,functionalized graphene
更新于2025-09-09 09:28:46
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CuO Thin Films Functionalized with Gold Nanoparticles for Conductometric Carbon Dioxide Gas Sensing
摘要： Metal oxides (MOx) are a well-established material for gas sensing. MOx-based gas sensors are sensitive to a wide variety of gases. Furthermore, these materials can be applied for the fabrication of low-cost and -power consumption devices in mass production. The market of carbon dioxide (CO2) gas sensors is mainly dominated by infra-red (IR)-based gas sensors. Only a few MOx materials show a sensitivity to CO2 and so far, none of these materials have been integrated on CMOS platforms suitable for mass production. In this work, we report a cupric oxide (CuO) thin film-based gas sensor functionalized with gold (Au) nanoparticles, which exhibits exceptional sensitivity to CO2. The CuO-based gas sensors are fabricated by electron beam lithography, thermal evaporation and lift-off process to form patterned copper (Cu) structures. These structures are thermally oxidized to form a continuous CuO film. Gold nanoparticles are drop-coated on the CuO thin films to enhance their sensitivity towards CO2. The CuO thin films fabricated by this method are already sensitive to CO2; however, the functionalization of the CuO film strongly increases the sensitivity of the base material. Compared to the pristine CuO thin film the Au functionalized CuO film shows at equal operation temperatures (300 ?C) an increase of sensitivity towards the same gas concentration (e.g., 2000 ppm CO2) by a factor of 13. The process flow used to fabricate Au functionalized CuO gas sensors can be applied on CMOS platforms in specific post processing steps.
关键词： metal oxides,CMOS integration,CO2,gas sensors,CuO
更新于2025-09-09 09:28:46
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[Energy, Environment, and Sustainability] Sensors for Automotive and Aerospace Applications || Leakage Monitoring in Inflatable Space Antennas: A Perspective to Sensitive Detection of Helium and Nitrogen Gases
摘要： In?atable space structures have become an important part of space explorations due to their lightweight, simpler design, low cost, and fewer parts. These structures include antennas, solar arrays, solar concentrators, re?ectors, etc. These structures are made of ?exible polymers which can be folded and easily carried with spacecraft due to their small volume and weight. Structures, when reaching their destination, are in?ated through internal pressurization to achieve desired structural integrity. In space, these structures are subjected to very harsh environment such as high radiation levels, structural vibrations, and micrometeoroid bombardments. The polymeric material used to fabricate these structures is susceptible to degradation under these harsh conditions. These structures are prone to lose their structural integrity over long-term degradation of the material. The most common problem associated with in?ated space antennas is leakage of in?ated gas. Hence, the health monitoring of these structures becomes crucial to avoid structural failure due to leakages which may cause loss of information, accuracy, and money. Gas sensors are used to detect leakages in these structures. A mixture of helium (He) and nitrogen (N2) is used as in?ating gas in space antennas. Helium is the lightest gas after hydrogen and has chemically inert, non?ammable nature which makes it an ideal in?ating gas. However, the detection of He leakages is very dif?cult because of its nonreactive behavior with chemical species. Metal oxide based semiconducting (MOSs) materials are widely used sensing element for detection of various gases. Although it is very dif?cult to ?nd out He gas leakages, vanadium pentoxide (V2O5) can detect even a small concentration of He through resistive changes. In this chapter, we will discuss the requirement of leakage monitoring system for in?atable space antennas and He gas sensing properties of V2O5 semiconducting material.
关键词： Helium detection,Metal oxide semiconductors,Gas sensors,In?atable space structures
更新于2025-09-09 09:28:46
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Near-Room-Temperature Ethanol Gas Sensor Based on Mesoporous Ag/Zn-LaFeO <sub/>3</sub> Nanocomposite
摘要： The rational design of heterojunction between different metal oxides with mesoporous structures has attracted tremendous attention due to their special physicochemical properties and vital importance for practical applications. In this paper, mesoporous Ag/Zn–LaFeO3 nanocomposite is successfully synthesized through a facile nanocasting technique using KIT-6 as a hard template in sol–gel route and used as sensing materials to achieve an exceptionally sensitive and selective detection of trace ppm-level ethanol. The obtained composite possesses high surface area and exhibits excellent sensing response (64.2 for 100 ppm) to ethanol at near-room with relatively fast response/recovery time. When tested with the concentrations as low as 5 ppm, it also shows a remarkably high selectivity to the ethanol, but only minor responses to other interfering gases. These enhanced gas-sensing properties are attributed to the combination of mesoporous nanostructure and Ag/Zn–LaFeO3 heterogeneous composites.
关键词： mesoporous,ethanol,gas sensors,near-room temperature,Ag/Zn–LaFeO3 nanocomposite
更新于2025-09-09 09:28:46
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Gallium Oxide || Growth, properties, and applications of β-Ga2O3 nanostructures
摘要： This chapter provided a brief overview for β-Ga2O3 nanostructures from a growth aspect to device applications. The outstanding properties of β-Ga2O3 such as large bandgap, high breakdown field, thermal and chemical stability, along with advantageous properties due to its nanostructures morphology such as large surface-to-volume ratio, fewer defects, and less strain makes it a potential material for development of high-performance nanoscale devices. β-Ga2O3 nanostructures have shown great promise for nanoscale devices such as deep-UV photodetectors, gas sensors, and FETs. In addition, functional nanowires based on β-Ga2O3 nanostructures can also be utilized for establishing the nanoscale device platform.
关键词： device applications,photodetectors,FETs,β-Ga2O3 nanostructures,gas sensors,growth techniques
更新于2025-09-09 09:28:46
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Printable Fabrication of a Fully Integrated and Self-Powered Sensor System on Plastic Substrates
摘要： Wearable and portable devices with desirable flexibility, operational safety, and long cruising time, are in urgent demand for applications in wireless communications, multifunctional entertainments, personal healthcare monitoring, etc. Herein, a monolithically integrated self-powered smart sensor system with printed interconnects, printed gas sensor for ethanol and acetone detection, and printable supercapacitors and embedded solar cells as energy sources, is successfully demonstrated in a wearable wristband fashion by utilizing inkjet printing as a proof-of-concept. In such a “wearable wristband”, the harvested solar energy can either directly drive the sensor and power up a light-emitting diode as a warning signal, or can be stored in the supercapacitors in a standby mode, and the energy released from supercapacitors can compensate the intermittency of light illumination. To the best of our knowledge, the demonstration of such a self-powered sensor system integrated onto a single piece of flexible substrate in a printable and additive manner has not previously been reported. Particularly, the printable supercapacitors deliver an areal capacitance of 12.9 mF cm?2 and the printed SnO2 gas sensor shows remarkable detection sensitivity under room temperature. The printable strategies for device fabrication and system integration developed here show great potency for scalable and facile fabrication of a variety of wearable devices.
关键词： wearable and flexible devices,printable supercapacitors,printable gas sensors,monolithically integrated self-powered systems,inkjet printing
更新于2025-09-09 09:28:46