Nanostructured TiO2 Layers for Photovoltaic and Gas Sensing Applications

Titanium dioxide (TiO2) has been an important material for decades, combining numerous attractive properties in terms of economy (low price, large availability) or ecology (non-toxic), as well as broad physical and chemical possibilities. In the last few years, the development of nanotechnologies offered new opportunities, not only in an academic perspective but also with a view to many applications with particular reference to the environment. This chapter focuses on the many ways that allow to tailor and organize TiO2 crystallites at the nanometre scale to make the most of this amazing material in the field of photovoltaics and gas sensing

Finding Hydrogen Leaks by Means of the Fiber Bragg Gratings Technology

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High-temperature NO sensing performance of WO3 deposited by spray coating

This work reports the fabrication of sensors by a facile deposition of water-based ink blended commercial WO3 powders via spray coating on sensor platforms fitted with Au-interdigitated electrodes (IDEs) and the characterization of their sensing performances under hot NO-containing air at temperatures exceeding 500 °C. After deposition and heat treatment of the sensing material on the substrate fitted with Au-IDE at 700 °C, the composition and morphology of the active material were analyzed and the presence of a single phase, fine particulates of WO3, has been confirmed by XRD and SEM, respectively. The investigation of the sensing properties revealed that, contrary to the previous reports, this WO3 sensor can detect NO with a good sensitivity (∼22% for 200 ppm NO) and selectivity at 700 °C under humidity

Use of experimental sensors for discrimination of artificial breath mixtures in a lung cancer screening context

peer reviewedThe Pathacov project [3] aims at creating an electronic nose to detect lung cancer in the population at risk. Metal oxide sensors are being developed within the project to better detect cancer biomarkers, which are identified within a large-scale clinical study in university hospitals in the north-east of France. Before long and costly clinical trials, the performance of the prototype electronic nose has to be evaluated. In order to do this, a novel approach has been implemented. Real breath samples from healthy and available volunteers are collected in Teflon FEP sampling bags. The results of the electronic nose are processed through a principal component analysis (PCA) in order to evaluate the contribution of each sensor to the separation of the group’s clusters (healthy and cancer). This enables the selection of the best performing sensors to be included in the final prototype.Pathaco

Past, present, and future trends in boar taint detection

peer reviewedBackground: Boar taint is an unpleasant smell found in the meat of some uncastrated male pigs. This taint is often prevented by surgical castration without anesthesia or analgesia. However, this practice is an animal welfare concern. Production of entire males and immunocastration were suggested as alternatives. Ensuring that meat is untainted remains a priority for slaughterhouses. This has initiated research about the development of new boar taint detection methods. Most focus on detecting skatole and androstenone, two major contributors to boar taint. Scope and approach: This review aims to describe past methods and recent advances made in rapid boar taint detection, and provide leads for future research. The main findings of past methods such as the use of insect behavior-based sensors, e-noses, and gas chromatography–mass spectrometry, are presented. Recently developed methods based on mass spectrometry, Raman spectroscopy, and sensors are also discussed. Finally, biosensors showing promising results and potential for boar taint detection are presented. The advantages and drawbacks of these techniques, cost analysis, and possible challenges encountered during their application to on-line detection are addressed. Key findings and conclusions: This review presents numerous techniques that were developed for boar taint detection. Some methods, such as laser diode thermal desorption combined with tandem mass spectrometry, proved their on-line/at-line efficiency as they are fast and accurate. However, initial investment and difficulty of implementation could lead to reluctance in applying these. Further research could focus on testing new sensor materials whereas sensory evaluation remains the most practical method used in slaughterhouses

Self-supported three-dimensionally interconnected polypyrrole nanotubes and nanowires for highly sensitive chemiresistive gas sensing

We developed a versatile template-based fabrication method for growing large arrays of threedimensionally interconnected polypyrrole nanotubes (or nanowires) with easily tunable geometrical dimensions and spatial arrangement. Such a macroscopic network made up of conducting polymer elongated nanostructures provides an extremely large active surface with increased electrical connectivity, as well as an enhanced structural integrity of the flexible network. The three-dimensional array of polypyrrole nanofibers exhibited an excellent sensitivity towards gaseous ammonia, providing reliable and accurate detection at gas concentrations as low as 1 ppm. The novel preparation approach offers a cost-effective alternative for large-scale production of easily integrable chemiresistive sensors for different applications

Reversible NO2 Optical Fiber Chemical Sensor Based on LuPc2 Using Simultaneous Transmission of UV and Visible Light

In this paper, an NO2 optical fiber sensor is presented for pollution monitoring in road traffic applications. This sensor exploits the simultaneous transmission of visible light, as a measurement signal, and UV light, for the recovery of the NO2 sensitive materials. The sensor is based on a multimode fiber tip coated with a thin film of lutetium bisphthalocyanine (LuPc2). The simultaneous injection of UV light through the fiber is an improvement on the previously developed NO2 sensors and allows the simplification of the sensor head, rendering the external UV illumination of the film unnecessary. Coatings of different thicknesses were deposited on the optical fiber tips and the best performance was obtained for a 15 nm deposited thickness, with a sensitivity of 5.02 mV/ppm and a resolution of 0.2 ppb in the range 0–5 ppm. The response and recovery times are not dependent on thickness, meaning that NO2 does not diffuse completely in the films

Electrochemical Detection of Penicillin G Using Molecularly Imprinted Conductive Co-Polymer Sensor

Antibiotics are increasingly used to treat certain bacteria that are harmful to humans. However, their inadequate or excessive use can lead to the proliferation of certain more resistant strains, which ultimately reduces their effectiveness. To counter this, it is essential to limit the amount of antibiotics ingested, particularly through animal food, if the animals themselves have received antibiotic treatment. In the case of milk, it is necessary to be able to detect quantities of antibiotics in the range of a few parts per billion. A sensor has therefore been developed for this purpose. The sensitive layer that we propose to use in this study, is based on a molecularly imprinted conductive polymer (MICP) that allows a very specific interaction and have been integrated into electrochemical detection approaches by polymerization on electrodes. The sensor is based on the measurement of the variation in conductivity of a sensitive layer deposited between two electrodes, which is influenced by the presence of the antibiotic. Although it seems possible to further improve the performance of these sensors, their use in this field seems very promising considering the obtained results

Electrochemical Detection of Penicillin G Using Molecularly Imprinted Conductive Co-Polymer Sensor

Antibiotics are increasingly used to treat certain bacteria that are harmful to humans. However, their inadequate or excessive use can lead to the proliferation of certain more resistant strains, which ultimately reduces their effectiveness. To counter this, it is essential to limit the amount of antibiotics ingested, particularly through animal food, if the animals themselves have received antibiotic treatment. In the case of milk, it is necessary to be able to detect quantities of antibiotics in the range of a few parts per billion. A sensor has therefore been developed for this purpose. The sensitive layer that we propose to use in this study, is based on a molecularly imprinted conductive polymer (MICP) that allows a very specific interaction and have been integrated into electrochemical detection approaches by polymerization on electrodes. The sensor is based on the measurement of the variation in conductivity of a sensitive layer deposited between two electrodes, which is influenced by the presence of the antibiotic. Although it seems possible to further improve the performance of these sensors, their use in this field seems very promising considering the obtained results