Studies on tin oxide-intercalated polyaniline nanocomposite for ammonia gas sensing applications
TL;DR: In this article, a tin oxide-intercalated polyaniline (PANI) nanocomposite has been deposited at room temperature, through solution route technique, and the as-grown films were studied for some of the useful physicochemical properties.
Abstract: Thin films of tin oxide-intercalated polyaniline nanocomposite have been deposited at room temperature, through solution route technique. The as-grown films were studied for some of the useful physicochemical properties, making use of XRD, FTIR, SEM, etc. and optical methods. XRD studies showed peak broadening and the peak positions shift from standard values, indicating presence of tin oxide in nanoparticles form in the polyaniline (PANI) matrix. FTIR study shows presence of the Sn–O–Sn vibrational peak and characteristic vibrational peaks of PANI. Study of SEM micrograph revealed that the composite particles have irregular shape and size with micellar templates of PANI around them. AFM images show topographical features of the nanocomposite similar to SEM images but at higher resolution. Optical absorbance studies show shifting of the characteristics peaks for PANI, which may be due to presence of tin oxide in PANI matrix. On exposure to ammonia gas (100–500 ppm in air) at room temperature, it was found that the PANI film resistance increases, while that of the nanocomposite (PANI + SnO2) film decreases from the respective unexposed value. These changes on removal of ammonia gas are reversible in nature, and the composite films showed good sensitivity with relatively faster response/recovery time. © 2009 Elsevier B.V. All rights reserved.
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TL;DR: In this paper, a detailed study of semiconductor metal oxide (SMO) gas sensors is provided for a detailed comparison of SMO gas sensors with other gas sensors, especially for ammonia gas sensing.
Abstract: This review paper encompasses a detailed study of semiconductor metal oxide (SMO) gas sensors. It provides for a detailed comparison of SMO gas sensors with other gas sensors, especially for ammonia gas sensing. Different parameters which affect the performance (sensitivity, selectivity and stability) of SMO gas sensors are discussed here under. This paper also gives an insight about the dopant or impurity induced variations in the SMO materials used for gas sensing. It is concluded that dopants enhance the properties of SMOs for gas sensing applications by changing their microstructure and morphology, activation energy, electronic structure or band gap of the metal oxides. In some cases, dopants create defects in SMOs by generating oxygen vacancy or by forming solid solutions. These defects enhance the gas sensing properties. Different nanostructures (nanowires, nanotubes, heterojunctions), other than nanopowders have also been studied in this review. At the end, examples of SMOs are given to illustrate the potential use of different SMO materials for gas sensing.
1,296 citations
TL;DR: The most important advances with regard to fundamental research, sensing mechanisms, and application of nanostructured materials for room-temperature conductometric sensor devices are reviewed here and particular emphasis is given to the relation between the nanostructure and sensor properties in an attempt to address structure-property correlations.
Abstract: Sensor technology has an important effect on many aspects in our society, and has gained much progress, propelled by the development of nanoscience and nanotechnology. Current research efforts are directed toward developing high-performance gas sensors with low operating temperature at low fabrication costs. A gas sensor working at room temperature is very appealing as it provides very low power consumption and does not require a heater for high-temperature operation, and hence simplifies the fabrication of sensor devices and reduces the operating cost. Nanostructured materials are at the core of the development of any room-temperature sensing platform. The most important advances with regard to fundamental research, sensing mechanisms, and application of nanostructured materials for room-temperature conductometric sensor devices are reviewed here. Particular emphasis is given to the relation between the nanostructure and sensor properties in an attempt to address structure-property correlations. Finally, some future research perspectives and new challenges that the field of room-temperature sensors will have to address are also discussed.
1,096 citations
TL;DR: In this paper, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscope (SEM), thermogravimetric analysis (TGA), and UV-vis spectrography and electrical conductivity of PANI-ZnO composites were analyzed.
364 citations
Cites background from "Studies on tin oxide-intercalated p..."
...conductive polymer because of the presence of the reactive – NH– groups in polymer chain [1–3], and used in broad applications such as batteries [4], sensors [5,6], electronic devices [7], supercapacitors [8] and corrosion protection in organic coatings [9–11] due to its physical and chemical properties, good electrical conductivity (p-type), high environmental stability, low cost [12,13], light weight, flexibility, facile fabrication and possibility of both chemical and electrochemical syntheses [14–16]....
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TL;DR: In this paper, an epoxy coating with an organic-inorganic hybrid nanocomposite as a corrosion inhibiting pigment applied over carbon steel grade ST37 was applied as a protective coating on carbon steel plates.
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TL;DR: In this article, a comprehensive review of the organic/inorganic hybrid sensors is provided, where several suggestions related to future development of organic and inorganic hybrid sensing materials are also made.
Abstract: Due to the synergetic or complementary effects between organic and inorganic components, which could result in improved properties or performances, the organic/inorganic hybrid materials have recently gained extensive interest in many fields. Up to date, many reports have been published based on the organic/inorganic hybrid materials for the sensor applications. The paper provided a comprehensive review about recent progress of the organic/inorganic hybrid sensors. The organic/inorganic hybrid sensing materials could be fabricated in several configuration types such as intercalating type, core–shell type, coating type and mixed type. The sensing form of the hybrid sensors could be presented in thin-film, thick-film or pellet form, and the sensing performances could by measured in the flowing or static-state system. The hybrid sensing materials have been applied in gas sensors, humidity sensors, ultraviolet sensors, strain sensors, electrochemical immunosensors and fluorescent chemosensors. Finally, several suggestions related to future development of organic/inorganic hybrid sensing materials were also made.
238 citations
References
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Journal Article•
TL;DR: In this paper, the authors look into the historical background, and present status and development prospects for photoelectrochemical cells, based on nanocrystalline materials and conducting polymer films.
Abstract: Until now, photovoltaics - the conversion of sunlight to electrical power - has been dominated by solid-state junction devices, often made of silicon. But this dominance is now being challenged by the emergence of a new generation of photovoltaic cells, based, for example, on nanocrystalline materials and conducting polymer films. These offer the prospect of cheap fabrication together with other attractive features, such as flexibility. The phenomenal recent progress in fabricating and characterizing nanocrystalline materials has opened up whole new vistas of opportunity. Contrary to expectation, some of the new devices have strikingly high conversion efficiencies, which compete with those of conventional devices. Here I look into the historical background, and present status and development prospects for this new generation of photoelectrochemical cells.
8,305 citations
TL;DR: Herein is described a novel, simple, and cheap method to prepare patterns of conducting polymers by a process which the authors term, "Line Patterning".
Abstract: Since the initial discovery in 1977, that polyacetylene (CH)(x), now commonly known as the prototype conducting polymer, could be p- or n-doped either chemically or electrochemically to the metallic state, the development of the field of conducting polymers has continued to accelerate at an unexpectedly rapid rate and a variety of other conducting polymers and their derivatives have been discovered. Other types of doping are also possible, such as "photo-doping" and "charge-injection doping" in which no counter dopant ion is involved. One exciting challenge is the development of low-cost disposable plastic/paper electronic devices. Conventional inorganic conductors, such as metals, and semiconductors, such as silicon, commonly require multiple etching and lithographic steps in fabricating them for use in electronic devices. The number of processing and etching steps involved limits the minimum price. On the other hand, conducting polymers combine many advantages of plastics, for example, flexibility and processing from solution, with the additional advantage of conductivity in the metallic or semiconducting regimes; however, the lack of simple methods to obtain inexpensive conductive polymer shapes/patterns limit many applications. Herein is described a novel, simple, and cheap method to prepare patterns of conducting polymers by a process which we term, "Line Patterning".
1,924 citations
Book•
01 Jan 1989
TL;DR: Silicon Based Chemical Sensors as mentioned in this paper : Gas Sensors based on Semiconductor Powders are used for solid state chemical sensor applications, and they have been shown to be useful in many applications.
Abstract: Introduction. Solid State Background. Solid/Gas Interfaces. Solid/Liquid Interfaces. Catalysis Background. Membrane Background. Biosensor Principles. Principles of Chemfet Operation. Silicon Based Chemical Sensors. Thin Film Gas Sensors. SolidElectrolytes-Devices. Gas Sensors Based on Semiconductor Powders. Application of Solid State Chemical Sensors.
953 citations
TL;DR: In this article, the effects of secondary doping on polyaniline and its derivatives are shown to be based primarily on a change in molecular conformation of the polymer from "compact coil" to "expanded coil".
823 citations
TL;DR: In this paper, a comparative vibrational analysis of leucoemeraldine, emeraldine, and pernigraniline bases is presented, where the authors determine the force constants, the potential energy distribution, and the Cartesian displacements for the three forms of polyaniline and associated model compounds.
Abstract: We present a comparative vibrational study of leucoemeraldine, emeraldine, and pernigraniline bases: fully reduced, half oxidized, and fully oxidized forms of polyaniline, respectively. By performing a general vibrational calculation based on the symmetrized dynamical matrix, we determine the force constants, the potential-energy distribution, and the Cartesian displacements for the three forms of polyaniline and associated model compounds. We discuss the assignment of the fundamental Raman and ir vibrational modes of the polymers. The modifications of the frequencies and consequently of the main force constants observed from one compound to the other are analyzed by considering the quinoid and aromatic characters along the chain. In this way, we determine a force field with physical significance which may be used to interpret the electronic modification between neutral and protonated as well as photoexcited emeraldine forms. This comparative analysis demonstrates the important changes of the electronic distribution around the nitrogen atom, which plays a major role in the conduction mechanism in this class of conducting polymers.
691 citations