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WO1999019719A1 - Detecteur nanocristallin et son procede de fabrication - Google Patents

Detecteur nanocristallin et son procede de fabrication Download PDF

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Publication number
WO1999019719A1
WO1999019719A1 PCT/EP1998/006439 EP9806439W WO9919719A1 WO 1999019719 A1 WO1999019719 A1 WO 1999019719A1 EP 9806439 W EP9806439 W EP 9806439W WO 9919719 A1 WO9919719 A1 WO 9919719A1
Authority
WO
WIPO (PCT)
Prior art keywords
sensor
nanoparticles
metal oxide
sensors
substrate
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/EP1998/006439
Other languages
German (de)
English (en)
Inventor
Patrick Keller
Jörg-Uwe MEYER
Hans Ferkel
Werner Riehemann
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung eV
Original Assignee
Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung eV
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung eV filed Critical Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung eV
Publication of WO1999019719A1 publication Critical patent/WO1999019719A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
    • G01N27/12—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid, for detecting components in the fluid
    • G01N27/125—Composition of the body, e.g. the composition of its sensitive layer
    • G01N27/127—Composition of the body, e.g. the composition of its sensitive layer comprising nanoparticles
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/0004—Gaseous mixtures, e.g. polluted air
    • G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
    • G01N33/0027—General constructional details of gas analysers, e.g. portable test equipment concerning the detector
    • G01N33/0036—General constructional details of gas analysers, e.g. portable test equipment concerning the detector specially adapted to detect a particular component
    • G01N33/004—CO or CO2

Definitions

  • the invention relates to a sensor, which is preferably intended for gas analysis and in particular for detecting carbon dioxide, with a layer containing at least one sensitive metal oxide, and to a method based on laser ablation.
  • sensors are developed and used for a wide variety of purposes. For example, there are currently pressure sensors, acceleration sensors, heat sensors and gas sensors. Gas sensors are used to determine and monitor the concentration of certain gases in the air. The carbon dioxide content of the room air is particularly important for the control of air conditioning and ventilation systems. The use of CO 2 sensors is also a prerequisite for the continuous control of biological and chemical processes in bio- and environmental technology as well as for climate monitoring in greenhouses, in order to influence the composition of the atmosphere to be monitored with additional devices. Further areas of application can be expected, for example, in the investigation of the combustion of fossil fuels, in occupational safety and health and in agriculture.
  • Solid state sensors detect the concentration of gases by their adsorption through sensitive layers, which usually consist of semiconducting materials, in particular metal oxides.
  • sensitive layers which usually consist of semiconducting materials, in particular metal oxides.
  • the adsorption of gas molecules on the sensor surface increases or decreases the number of free charge carriers and therefore results in a changed resistance or a changed conductivity of the sensitive layer.
  • Dipole moments of the adsorbed gas molecules also change the dielectric constant and thus also the capacitance of the sensor layer. Based on the known measurement of these changes, conclusions can be drawn about the amount of gas adsorbed and thus about the corresponding gas concentration of the surrounding room air.
  • conductivity and dielectric constant of the sensitive layer are measured at AC voltage.
  • the layer itself is usually located on a substrate surface covered with two electrodes, the electrodes usually being arranged in the form of two interdigitated comb structures, the so-called interdigital structure.
  • the conventional metal oxide sensors are very robust and therefore in demand for use even under rough conditions, but they have a disadvantageously low sensitivity.
  • they are provided with a heating device on the back of the substrate and operated at local temperatures of several hundred degrees Celsius. This results in a high energy consumption of the sensors, which is all the more serious as such sensors are to be used for continuous continuous monitoring.
  • the low sensitivity of the metal oxide must be compensated for by a correspondingly large sensor area in order to obtain evaluable and reliable measurement results. So far, this has stood in the way of a miniaturization of such solid-state sensors that is desirable per se.
  • the achievement of this object is specified for a sensor in claim 1 and for the manufacturing method in claim 5. Further developments of the invention are the subject of the dependent claims.
  • the object is achieved for a sensor in that the metal oxide consists of nanoparticles with typical grain sizes between preferably 3 and 30 nanometers.
  • the active surface of the sensor is increased considerably compared to conventional sensors, which results in a significantly higher sensitivity. This makes it possible to reduce the sensor area; in addition, the sensor according to the invention can also be operated at substantially lower operating temperatures of below 300 ° C. and thus more cost-effectively.
  • a first embodiment provides that the nanoparticles essentially contain barium titanate (BaTi0 3 ), and a further embodiment that the nanoparticles also contain at least one of the additives CuO, La 2 0 3 and CaC0 3 .
  • This system is particularly suitable for the detection of C0 2 .
  • the nanoparticles are embedded in an organic matrix.
  • An organic binder can be used if the sensitive material is not applied directly to the sensor substrate in the manner described below, but instead is applied using one of the common thick-film processes, such as the screen printing process.
  • the object is achieved according to the invention in that nanoparticles are produced and evaporated in situ on a substrate or the like.
  • the use of laser ablation according to the invention is directed to the nanoparticles produced thereby.
  • the composition of the nanoparticles can be influenced by the targeted control of the process parameters and by the composition of the starting materials.
  • Evaporation in situ ie during laser ablation, offers the advantage of direct application of the sensitive material from the substrate without first having to separate a powder, as in the case of the screen printing process, then mixing it with a binder and then applying it in a further step.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Immunology (AREA)
  • General Physics & Mathematics (AREA)
  • Pathology (AREA)
  • Physics & Mathematics (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Nanotechnology (AREA)
  • Electrochemistry (AREA)
  • Combustion & Propulsion (AREA)
  • Food Science & Technology (AREA)
  • Medicinal Chemistry (AREA)
  • Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)

Abstract

L'invention concerne un détecteur, de préférence pour analyser des gaz, et notamment pour détecter du dioxyde de carbone. Ce détecteur comporte au moins une couche contenant un métal sensible. L'invention concerne également un procédé fondé sur l'ablation par laser. L'oxyde métallique est constitué de nanoparticules présentant des granulométries typiques comprises de préférence entre 3 et 30 nanomètres en vue d'accroître la sensibilité du détecteur et sa plage de fonctionnement à une température inférieure à 300 DEG C et avec une surface de détection plus petite. En outre, le procédé décrit permet de produire des nanoparticules et de les métalliser sous vide in situ sur un substrat ou analogue.
PCT/EP1998/006439 1997-10-10 1998-10-12 Detecteur nanocristallin et son procede de fabrication Ceased WO1999019719A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19744857.7 1997-10-10
DE1997144857 DE19744857A1 (de) 1997-10-10 1997-10-10 Nanokristalliner Sensor und Herstellungsverfahren

Publications (1)

Publication Number Publication Date
WO1999019719A1 true WO1999019719A1 (fr) 1999-04-22

Family

ID=7845194

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP1998/006439 Ceased WO1999019719A1 (fr) 1997-10-10 1998-10-12 Detecteur nanocristallin et son procede de fabrication

Country Status (2)

Country Link
DE (1) DE19744857A1 (fr)
WO (1) WO1999019719A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000073534A1 (fr) * 1999-05-28 2000-12-07 Ultramet Procede de formation a basse temperature de revetements a base d'oxydes metalliques
WO2002036204A2 (fr) 2000-10-31 2002-05-10 Marat Vadimovich Evtukhov Systeme de survie integre

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6237397B1 (en) * 1999-10-06 2001-05-29 Iowa State University Research Foundation, Inc. Chemical sensor and coating for same
FR2816756B1 (fr) * 2000-11-15 2003-10-31 Univ Paris Curie Procede d'obtention d'une composition polymere dopee par des nanoparticules pour la realisation de materiaux composites polymeres, dispositif pour sa mise en oeuvre, composition et materiaux obtenus
JP3735686B2 (ja) 2001-10-30 2006-01-18 独立行政法人理化学研究所 金属酸化物強誘電体粒子結晶の製造方法
DE102004019639A1 (de) * 2004-04-22 2005-11-17 Siemens Ag FET-basierter Gassensor

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2208644A (en) * 1987-08-12 1989-04-12 Cabot Corp Doped BaTiO3 based compositions
US4863883A (en) * 1986-05-05 1989-09-05 Cabot Corporation Doped BaTiO3 based compositions
US5338430A (en) * 1992-12-23 1994-08-16 Minnesota Mining And Manufacturing Company Nanostructured electrode membranes
DE4325108A1 (de) * 1993-07-27 1995-02-02 Philips Patentverwaltung Verfahren zur Erzeugung ultrafeiner oxidischer Partikel

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4863883A (en) * 1986-05-05 1989-09-05 Cabot Corporation Doped BaTiO3 based compositions
GB2208644A (en) * 1987-08-12 1989-04-12 Cabot Corp Doped BaTiO3 based compositions
US5338430A (en) * 1992-12-23 1994-08-16 Minnesota Mining And Manufacturing Company Nanostructured electrode membranes
DE4325108A1 (de) * 1993-07-27 1995-02-02 Philips Patentverwaltung Verfahren zur Erzeugung ultrafeiner oxidischer Partikel

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
HAEUSLER A ET AL: "A novel thick film conductive type CO2 sensor", SENSORS AND ACTUATORS B, vol. 34, no. 1-3, August 1996 (1996-08-01), pages 388-395, XP004078011 *
TATSUMI ISHIHARA ET AL: "A NEW TYPE OF CO2 GAS SENSOR BASED ON CAPACITANCE CHANGES", SENSORS AND ACTUATORS B, vol. B05, no. 1 / 04, 1 August 1991 (1991-08-01), pages 97 - 102, XP000265943 *
TATSUMI ISHIHARA ET AL: "APPLICATION OF A MIXED OXIDE CAPACITOR TO THE SELECTIVE CARBON DIOXIDE SENSOR CO2 SENSING CHARACTERISTICS OF A CUO-BASED OXIDE CAPACITOR", JOURNAL OF THE ELECTROCHEMICAL SOCIETY, vol. 139, no. 10, 1 October 1992 (1992-10-01), pages 2881 - 2885, XP000358997 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000073534A1 (fr) * 1999-05-28 2000-12-07 Ultramet Procede de formation a basse temperature de revetements a base d'oxydes metalliques
WO2002036204A2 (fr) 2000-10-31 2002-05-10 Marat Vadimovich Evtukhov Systeme de survie integre

Also Published As

Publication number Publication date
DE19744857A1 (de) 1999-05-06

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