Accumulating gas sensor principle – how to come from concentration integration to real amount measurements

Abstract. The aim of this article is to introduce the operation principles of conductometric solid-state dosimeter-type gas sensors, which have found increased attention in the past few years, and to give a literature overview on promising materials for this purpose. Contrary to common gas sensors, gas dosimeters are suitable for directly detecting the dose (also called amount or cumulated or integrated exposure of analyte gases) rather than the actual analyte concentration. Therefore, gas dosimeters are especially suited for low level applications with the main interest on mean values. The applied materials are able to change their electrical properties by selective accumulation of analyte molecules in the sensitive layer. The accumulating or dosimeter-type sensing principle is a promising method for reliable, fast, and long-term detection of low analyte levels. In contrast to common gas sensors, few devices relying on the accumulation principle are described in the literature. Most of the dosimeter-type devices are optical, mass sensitive (quartz microbalance/QMB, surface acoustic wave/SAW), or field-effect transistors. The prevalent focus of this article is, however, on solid-state gas dosimeters that allow a direct readout by measuring the conductance or the impedance, which are both based on materials that change (selectively in ideal materials) their conductivity or dielectric properties with gas loading. This overview also includes different operation modes for the accumulative sensing principle and its unique features.

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“…4, the setupdependent gas velocity across the sensitive material was found to affect the analyte sorption (Beulertz et al, 2011.…”

Section: Influencing Factorsmentioning

confidence: 97%

“…2.1). Beulertz et al (2011) investigated the influence of the flow rate on the sensor response of a carbonate-based NO x dosimeter. Figure 8a depicts the time course of the sensor response |SR| = |∆R| / R 0 of the NO x dosimeter in the planar sensor setup at various flow rates.…”

Section: Dosimeter Setup Configurationsmentioning

confidence: 99%

Overview on conductometric solid-state gas dosimeters

Marr

Groß²,

Moos

2014

J. Sens. Sens. Syst.

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“…Alternatively, accumulating gas sensors capable of measuring the lean analyte by detecting the total amount of the analyte passing the sensor over a given time interval are still under development. , Although this method has a notable advantage in detecting gases mixed with low concentration of toxic gases, the manufacturing process of these sensorslike other gas sensorsis complicated; moreover, the wired data acquisition system creates limitations in assembling and monitoring such numerous sensors simultaneously.…”

Section: Introductionmentioning

confidence: 99%

Nanoscale Ag/WO₃ Multilayered Fabry–Perot Cavities for Colorimetric NO₂ Sensing

Kim

Cho

Lee

et al. 2021

ACS Appl. Nano Mater.

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High-performance gas sensors with low operating temperatures are of emerging research interest. They do not require heaters, thus guaranteeing cost-effectiveness and low power consumption. This is a study to demonstrate the possibility of fabricating a high-performance sensor through a simplified mechanism based on the surface property changes of a Fabry–Perot cavity. Here, the upper metal reacts independently, allowing accurate analyses to be performed while minimizing errors due to external factors. The proposed sensor rapidly responds to corrosive gases; it shifts the absorption wavelength by over 45 nm, that is, from 552 to 597 nm within 15 min at room temperature, significantly changes the color from purple to blue, and can be fabricated in bulk using conventional electron-beam physical vapor deposition. NO2 gas experiments verify the sensor’s superior performance and productivity potential, demonstrating its applicability in urban areas and factories.

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“…The analyte flow rate influences the performance of every gas sensor; thus, most of these sensors usually contain a diffusion barrier (layer, cover or inlet) that may prevent the negative impact of a sudden change of direction and/or the rate of analyte flow, as well as various unwanted impacts from the surrounding environment [17]. Several authors described the effect of the flow rate on the signal and sensor properties of gas sensors [18][19][20][21]. Our previous paper [21] demonstrated on a fully-printed amperometric gas sensor that the direct current (DC) through the sensor exhibits changes within the range of one order for a non-zero flow rate, while the spectral density of current fluctuations significantly changes its shape and the level of current fluctuations in the power spectrum for the orders as the flow rate increases at a constant concentration of the detected gas.…”

Section: Introductionmentioning

confidence: 99%

The Effect of the Orientation Towards Analyte Flow on Electrochemical Sensor Performance and Current Fluctuations

Sedlák

Kuberský

2020

Sensors

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Analyte flow influences the performance of every gas sensor; thus, most of these sensors usually contain a diffusion barrier (layer, cover, inlet) that can prevent the negative impact of a sudden change of direction and/or the rate of analyte flow, as well as various unwanted impacts from the surrounding environment. However, several measurement techniques use the modulation of the flow rate to enhance sensor properties or to extract more information about the chemical processes that occur on a sensitive layer or a working electrode. The paper deals with the experimental study on how the analyte flow rate and the orientation of the electrochemical sensor towards the analyte flow direction influence sensor performance and current fluctuations. Experiments were carried out on a semi-planar, three-electrode topology that enabled a direct exposure of the working (sensing) electrode to the analyte without any artificial diffusion barrier. The sensor was tested within the flow rate range of 0.1-1 L/min and the orientation of the sensor towards the analyte flow direction was gradually set to the four angles 0 • , 45 • , 90 • and 270 • in the middle of the test chamber, while the sensor was also investigated in the standard position at the bottom of the chamber.

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Accumulating gas sensor principle – how to come from concentration integration to real amount measurements

Cited by 3 publications

References 3 publications

Overview on conductometric solid-state gas dosimeters

Overview on conductometric solid-state gas dosimeters

Nanoscale Ag/WO₃ Multilayered Fabry–Perot Cavities for Colorimetric NO₂ Sensing

The Effect of the Orientation Towards Analyte Flow on Electrochemical Sensor Performance and Current Fluctuations

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Accumulating gas sensor principle – how to come from concentration integration to real amount measurements

Cited by 3 publications

References 3 publications

Overview on conductometric solid-state gas dosimeters

Overview on conductometric solid-state gas dosimeters

Nanoscale Ag/WO3 Multilayered Fabry–Perot Cavities for Colorimetric NO2 Sensing

The Effect of the Orientation Towards Analyte Flow on Electrochemical Sensor Performance and Current Fluctuations

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Product

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Nanoscale Ag/WO₃ Multilayered Fabry–Perot Cavities for Colorimetric NO₂ Sensing