Publication detail

Effect of analyte flow on the voltage fluctuations of gas chemiresistors

MÍVALT, F. SEDLÁKOVÁ, V. MAJZNER, J. KUBERSKÝ, P. SMULKO, J. SEDLÁK, P.

Original Title

Effect of analyte flow on the voltage fluctuations of gas chemiresistors

English Title

Effect of analyte flow on the voltage fluctuations of gas chemiresistors

Language

en

Original Abstract

Understanding of sensor mechanisms and their properties is tightly bounded with characterization of electric charge transport and its fluctuations at/in active electrochemical interfaces. Stochastic behavior becomes an increasingly dominant characteristic of electrochemical systems as we probe them on the smaller scales 1,2. This stochasticity is completely hidden from the observer due to massive averaging – so many charge carriers (electron, ions or molecules) are involved that only their mean behavior is observable and a probabilistic description is unnecessary. Nevertheless, the effect of randomness may show significance in some systems, especially very small ones in comparison to the macroscopic world but larger than microscopic scale of molecules, as the averaging of the random particle motion is not so effective 1,3,4. For example, the kinetics of many physico-chemical, electrochemical, and bioelectrochemical processes is known to be accompanied by noise generation, which virtually represents the dynamic fluctuations of electric potential or current2. Even though not every sensor system is considered as a small - mesoscopis, several authors showed that fluctuation analyses represent the approach of extracting more selective response from macroscopic chemical sensors, e.g. chemiresistors5–8, surface acoustic wave sensors, and resonant sensors9. In conductometric sensors the observed fluctuations give more information than a single DC resistance value and therefore obtained results lead to the reduction of the number of gas sensors necessary for the detection of different gas mixtures by sensor arrays 7,10. The high-order statistics enables the extraction of non-conventional features and leads to significant improvements in selectivity and sensitivity 7,8 of sensors. Another way to improve selectivity and sensitivity of conductometric sensors is targeted change of their operating conditions, such as temperature modulation8,11, light exposure of sensitive layer with various intensity12, sampling-and-hold method13, transient flow modulation14,15, etc. Our motivation aims on possibility of improved selectivity by modulation of analyte flow rate around conductometric sensors at equilibrium conditions by studying voltage fluctuations. By setting different flowrate, the concentration of analytes at the surface of sensors is modulated, and the specific response patterns, which are characteristic of the analytes present, develop. The method could be adapted to both static and dynamic headspace sampling strategies. However, this contribution aims to present how the flow rate of analyte affects the voltage fluctuation of the resistive gas sensor, which has not yet been sufficiently presented (PDF) Effect of analyte flow on the voltage fluctuations of gas chemiresistors.

English abstract

Understanding of sensor mechanisms and their properties is tightly bounded with characterization of electric charge transport and its fluctuations at/in active electrochemical interfaces. Stochastic behavior becomes an increasingly dominant characteristic of electrochemical systems as we probe them on the smaller scales 1,2. This stochasticity is completely hidden from the observer due to massive averaging – so many charge carriers (electron, ions or molecules) are involved that only their mean behavior is observable and a probabilistic description is unnecessary. Nevertheless, the effect of randomness may show significance in some systems, especially very small ones in comparison to the macroscopic world but larger than microscopic scale of molecules, as the averaging of the random particle motion is not so effective 1,3,4. For example, the kinetics of many physico-chemical, electrochemical, and bioelectrochemical processes is known to be accompanied by noise generation, which virtually represents the dynamic fluctuations of electric potential or current2. Even though not every sensor system is considered as a small - mesoscopis, several authors showed that fluctuation analyses represent the approach of extracting more selective response from macroscopic chemical sensors, e.g. chemiresistors5–8, surface acoustic wave sensors, and resonant sensors9. In conductometric sensors the observed fluctuations give more information than a single DC resistance value and therefore obtained results lead to the reduction of the number of gas sensors necessary for the detection of different gas mixtures by sensor arrays 7,10. The high-order statistics enables the extraction of non-conventional features and leads to significant improvements in selectivity and sensitivity 7,8 of sensors. Another way to improve selectivity and sensitivity of conductometric sensors is targeted change of their operating conditions, such as temperature modulation8,11, light exposure of sensitive layer with various intensity12, sampling-and-hold method13, transient flow modulation14,15, etc. Our motivation aims on possibility of improved selectivity by modulation of analyte flow rate around conductometric sensors at equilibrium conditions by studying voltage fluctuations. By setting different flowrate, the concentration of analytes at the surface of sensors is modulated, and the specific response patterns, which are characteristic of the analytes present, develop. The method could be adapted to both static and dynamic headspace sampling strategies. However, this contribution aims to present how the flow rate of analyte affects the voltage fluctuation of the resistive gas sensor, which has not yet been sufficiently presented (PDF) Effect of analyte flow on the voltage fluctuations of gas chemiresistors.

Keywords

Gas sensor;Current fluctuations;Flow;Modulation;Amperometric;Signal-to-noise ratio

Released

09.07.2018

Location

Gdansk

Pages from

134

Pages to

135

Pages count

154

URL

Documents

BibTex


@inproceedings{BUT165370,
  author="Filip {Mívalt} and Vlasta {Sedláková} and Jiří {Majzner} and Petr {Kuberský} and Janusz {Smulko} and Petr {Sedlák}",
  title="Effect of analyte flow on the voltage fluctuations of gas chemiresistors",
  annote="Understanding  of  sensor  mechanisms  and  their  properties  is tightly  bounded  with  characterization  of  electric  charge  transport and its fluctuations at/in active electrochemical interfaces. Stochastic    behavior    becomes    an    increasingly    dominant characteristic of electrochemical systems as we probe them on the smaller scales 1,2.  This stochasticity is completely hidden from the observer  due  to  massive  averaging –  so  many  charge  carriers (electron,  ions  or  molecules)  are  involved  that  only  their  mean behavior    is    observable    and    a    probabilistic    description    is unnecessary.  Nevertheless,  the  effect  of  randomness  may  show significance   in   some   systems,   especially   very   small   ones   in comparison to the macroscopic world but larger than microscopic scale of molecules, as the averaging of the random particle motion is not so effective 1,3,4. For example, the kinetics of many physico-chemical,  electrochemical,  and  bioelectrochemical  processes  is known  to  be  accompanied  by  noise  generation,  which  virtually represents the dynamic fluctuations of electric potential or current2.  Even  though  not  every  sensor  system  is  considered  as  a  small  - mesoscopis,   several   authors   showed   that   fluctuation   analyses represent the approach of extracting more selective response from macroscopic   chemical   sensors,   e.g.   chemiresistors5–8,   surface acoustic  wave  sensors,  and  resonant  sensors9.    In  conductometric sensors  the  observed  fluctuations  give  more  information  than  a single DC resistance value and therefore obtained results lead to the reduction of the number of gas sensors necessary for the detection of  different  gas  mixtures  by  sensor  arrays 7,10.  The  high-order statistics  enables  the  extraction  of  non-conventional  features  and leads  to  significant  improvements  in  selectivity  and  sensitivity 7,8 of sensors. Another    way    to    improve    selectivity    and    sensitivity    of conductometric   sensors   is   targeted   change of   their   operating conditions,  such  as  temperature  modulation8,11,  light  exposure  of sensitive    layer    with    various    intensity12, sampling-and-hold method13, transient flow modulation14,15, etc. Our  motivation  aims  on  possibility  of  improved  selectivity  by modulation of  analyte flow rate around conductometric sensors at equilibrium conditions by studying voltage fluctuations. By setting different  flowrate,  the  concentration  of  analytes  at  the  surface  of sensors is modulated, and the specific response patterns, which are characteristic  of  the  analytes  present,  develop.  The  method  could be   adapted   to   both   static   and   dynamic   headspace   sampling strategies. However, this contribution aims to present how the flow rate  of  analyte  affects  the  voltage  fluctuation  of  the  resistive  gas sensor, which has not yet been sufficiently presented 

(PDF) Effect of analyte flow on the voltage fluctuations of gas chemiresistors.",
  booktitle="Book of Abstracts - 8th International Conference on Unsolved Problems on Noise",
  chapter="165370",
  howpublished="online",
  year="2018",
  month="july",
  pages="134--135"
}