CN114791445B - Noble metal modified composite gas sensor - Google Patents
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- CN114791445B CN114791445B CN202210463275.3A CN202210463275A CN114791445B CN 114791445 B CN114791445 B CN 114791445B CN 202210463275 A CN202210463275 A CN 202210463275A CN 114791445 B CN114791445 B CN 114791445B
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- 229910000510 noble metal Inorganic materials 0.000 title claims abstract description 39
- 239000002131 composite material Substances 0.000 title claims abstract description 16
- 239000004065 semiconductor Substances 0.000 claims abstract description 161
- 229910044991 metal oxide Inorganic materials 0.000 claims abstract description 155
- 150000004706 metal oxides Chemical class 0.000 claims abstract description 155
- 229910021389 graphene Inorganic materials 0.000 claims abstract description 23
- 239000002082 metal nanoparticle Substances 0.000 claims abstract description 23
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 22
- 239000000758 substrate Substances 0.000 claims abstract description 11
- 230000004044 response Effects 0.000 claims abstract description 10
- 239000000463 material Substances 0.000 claims description 11
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 9
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical group O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims description 4
- 229910052697 platinum Inorganic materials 0.000 claims description 4
- 239000010931 gold Substances 0.000 claims description 3
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims description 2
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 claims description 2
- 229910052737 gold Inorganic materials 0.000 claims description 2
- 239000002105 nanoparticle Substances 0.000 claims description 2
- 229910052709 silver Inorganic materials 0.000 claims description 2
- 239000004332 silver Substances 0.000 claims description 2
- 239000010970 precious metal Substances 0.000 claims 2
- 230000000737 periodic effect Effects 0.000 claims 1
- 239000010408 film Substances 0.000 description 108
- 239000007789 gas Substances 0.000 description 88
- 239000001301 oxygen Substances 0.000 description 33
- 229910052760 oxygen Inorganic materials 0.000 description 33
- -1 oxygen anions Chemical class 0.000 description 18
- 230000035945 sensitivity Effects 0.000 description 17
- 239000010409 thin film Substances 0.000 description 17
- 230000008859 change Effects 0.000 description 16
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 15
- 238000006722 reduction reaction Methods 0.000 description 12
- 238000001514 detection method Methods 0.000 description 10
- 230000005684 electric field Effects 0.000 description 9
- 238000000034 method Methods 0.000 description 8
- 238000007254 oxidation reaction Methods 0.000 description 7
- 238000006479 redox reaction Methods 0.000 description 7
- 238000006243 chemical reaction Methods 0.000 description 6
- 239000002784 hot electron Substances 0.000 description 6
- 239000002086 nanomaterial Substances 0.000 description 6
- 230000009471 action Effects 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 230000008569 process Effects 0.000 description 5
- 238000001179 sorption measurement Methods 0.000 description 5
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 4
- 238000005286 illumination Methods 0.000 description 4
- 238000002360 preparation method Methods 0.000 description 4
- 238000002198 surface plasmon resonance spectroscopy Methods 0.000 description 4
- 230000005284 excitation Effects 0.000 description 3
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000003487 electrochemical reaction Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 230000000007 visual effect Effects 0.000 description 2
- 239000011787 zinc oxide Substances 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 1
- QPLDLSVMHZLSFG-UHFFFAOYSA-N Copper oxide Chemical compound [Cu]=O QPLDLSVMHZLSFG-UHFFFAOYSA-N 0.000 description 1
- 239000005751 Copper oxide Substances 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- FSAJRXGMUISOIW-UHFFFAOYSA-N bismuth sodium Chemical compound [Na].[Bi] FSAJRXGMUISOIW-UHFFFAOYSA-N 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 229910000431 copper oxide Inorganic materials 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- MEFBJEMVZONFCJ-UHFFFAOYSA-N molybdate Chemical compound [O-][Mo]([O-])(=O)=O MEFBJEMVZONFCJ-UHFFFAOYSA-N 0.000 description 1
- 239000002114 nanocomposite Substances 0.000 description 1
- 239000002073 nanorod Substances 0.000 description 1
- 239000002135 nanosheet Substances 0.000 description 1
- 239000002077 nanosphere Substances 0.000 description 1
- 239000002070 nanowire Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000011946 reduction process Methods 0.000 description 1
- 238000007650 screen-printing Methods 0.000 description 1
- 238000004528 spin coating Methods 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 description 1
- 229910001887 tin oxide Inorganic materials 0.000 description 1
- 239000004408 titanium dioxide Substances 0.000 description 1
- 238000010023 transfer printing Methods 0.000 description 1
- ITRNXVSDJBHYNJ-UHFFFAOYSA-N tungsten disulfide Chemical compound S=[W]=S ITRNXVSDJBHYNJ-UHFFFAOYSA-N 0.000 description 1
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
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Nanotechnology (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
Abstract
The application relates to the field of semiconductor gas sensors, and particularly provides a noble metal modified composite gas sensor which comprises a substrate layer, an electrode layer, a metal oxide semiconductor film layer and a response layer, wherein the electrode layer comprises a positive electrode and two negative electrodes, the metal oxide semiconductor film layer comprises a first metal oxide semiconductor film and two second metal oxide semiconductor films, and the response layer comprises a graphene film and noble metal nano particles. The positive electrode is positioned at the middle position of the basal layer, the negative electrodes are arranged at two sides of the basal layer, the first metal oxide semiconductor film is covered above the positive electrodes, and the second metal oxide semiconductor film is covered above the two negative electrodes. A graphene film is fixedly arranged above the first metal oxide semiconductor film, and noble metal nano particles are fixedly arranged above the two second metal oxide semiconductor films.
Description
Technical Field
The application relates to the field of semiconductor gas sensors, in particular to a noble metal modified composite gas sensor.
Background
A gas sensor is a sensor device capable of converting information about the type, concentration, composition and the like of gas into visual electric signals for output, and a specific conversion process utilizes various chemical reactions, various physical mechanisms and the like.
The working principle of the gas sensor is that the change of the microstructure in the gas sensor is converted into a visual electric signal when reacting with the gas to be detected. Because gases are very classified into various types and different gases generally have unique properties, even the same type of gases may have slight differences, and thus gas sensors having a gas-to-electric conversion function are also classified into semiconductor gas sensors and non-semiconductor gas sensors according to structural materials. The traditional gas sensor disclosed in the publication of journal "Journal of Alloys and Compounds", the publication of "Room-temperature ammonia gas sensor based on reduced graphene oxide nanocomposites decorated by Ag,Au and Pt nanoparticles", the publication of journal "Sensors and Actuators A: physical", the publication of "Room temperature conductive TYPE METAL oxide semiconductor gas sensors for NO 2 detection", and the publication of journal "ACS APPLIED MATERIALS & Interfaces", the publication of "Low voltage driven sensors based on ZnO nanowires for room temperature detection of NO2and CO gases", all require high temperature thermal excitation to ensure gas sensitivity, and the general operating temperature is 250-450 ℃, which not only consumes much power, but also reduces the stability and life of the gas sensor due to the change of crystal phase of the material and the agglomeration growth of crystal grains, and limits the application of the gas sensor in the flammable and explosive gas detection field. Therefore, the existing gas sensor has low sensitivity, especially in a low temperature environment.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provide a noble metal modified composite gas sensor so as to solve the problems of the noble metal modified composite gas sensor in the prior art.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
The application provides a noble metal modified composite gas sensor, which comprises a basal layer, an electrode layer, a metal oxide semiconductor film layer and a response layer, wherein the electrode layer comprises a positive electrode and two negative electrodes, the metal oxide semiconductor film layer comprises a first metal oxide semiconductor film and two second metal oxide semiconductor films, and the response layer comprises a graphene film and noble metal nano particles. The base layer is made of aluminum oxide, and plays a role in supporting and protecting the sensor, three electrodes are fixedly arranged on the base layer, wherein the positive electrode is located at the middle position, the negative electrodes are arranged on two sides, a first metal oxide semiconductor film is covered above the positive electrodes, a second metal oxide semiconductor film is covered above the two negative electrodes, and the two second metal oxide semiconductor films are communicated through the first metal oxide semiconductor film. The material of the first metal oxide semiconductor film is a first metal oxide semiconductor, the material of the second metal oxide semiconductor film is a second metal oxide semiconductor, the materials of the first metal oxide semiconductor and the second metal oxide semiconductor are different, and specifically, the fermi level of the first metal oxide semiconductor is lower than that of the second metal oxide semiconductor. The graphene film is fixedly arranged above the first metal oxide semiconductor film, is of a porous structure and has high adsorption capacity, and can adsorb air and gas to be detected on the surface of the first metal oxide semiconductor film so that the air and the gas to be detected participate in oxidation-reduction reaction. Noble metal nano particles are fixedly arranged above the two second metal oxide semiconductor films and used for generating a plasmon effect under the action of illumination.
When the method is applied, under the action of illumination, surface plasmon resonance is generated on the surfaces of the noble metal nano particles, electric field energy is concentrated on the surfaces of the noble metal nano particles, hot electrons are generated by excitation of a strong electric field, and as the fermi level of the first metal oxide semiconductor is lower than that of the second metal oxide semiconductor, the hot electrons flow to the first metal oxide semiconductor film in the middle from the second metal oxide semiconductor films at two sides, so that the electron concentration in the first metal oxide semiconductor film is higher, and thus oxygen molecules in the air can capture electrons in the first metal oxide semiconductor film, oxidation reaction is generated between the oxygen molecules and the electrons, and oxygen anions are generated, so that the electron concentration in the first metal oxide semiconductor film is reduced, and the resistance is greatly increased; then, the gas to be detected is contacted with the sensor, and molecules of the gas to be detected are adsorbed on the surface of the first metal oxide semiconductor film under the adsorption action of the graphene film and generate reduction reaction with oxygen anions, the oxygen anions are reduced into oxygen and simultaneously release electrons, and the released electrons return to the inside of the first metal oxide semiconductor film again, so that the concentration of electrons in the first metal oxide semiconductor film is increased drastically, and the resistance value is reduced. The change of the resistance is monitored through the electrode so as to realize the detection of the gas to be detected.
Compared with the prior art, the application has the beneficial effects that: the application provides a noble metal modified composite gas sensor. According to the application, the graphene film is adopted to adsorb air and gas to be detected, so that oxygen molecules in the air and the gas molecules to be detected are fully contacted with the surface of the first metal oxide semiconductor film, and the oxidation-reduction reaction is fully carried out. The metal oxide film is formed by stacking nano materials, the specific surface area of the nano materials is large, and oxygen molecules and gas molecules to be detected are in more sufficient contact with the surface of the first metal oxide semiconductor film, so that the oxidation-reduction reaction is more sufficient. The noble metal nano particles generate surface plasmon resonance under illumination, hot electrons excited by a strong electric field on the surfaces of the noble metal nano particles flow to the final first metal oxide semiconductor film through the second metal oxide semiconductor film, so that the electron concentration in the first metal oxide semiconductor film is higher, the oxidation reaction intensity generated with oxygen molecules in the air is higher, more oxygen anions are generated, and finally the reduction reaction intensity of the oxygen anions and the gas molecules to be detected is higher. The intensity of the oxidation-reduction reaction is higher, so that more electrons are released when oxygen anions react with molecules of the gas to be detected in a reduction way, and the resistance of the sensor is reduced more, and therefore, the gas sensor has higher sensitivity.
Drawings
Fig. 1 is a schematic diagram of a noble metal modified composite gas sensor provided by the invention.
Fig. 2 is a schematic diagram of a top view of an electrode layer of a noble metal modified composite gas sensor according to the present invention.
Icon: 1-a substrate layer; 2-electrode layers; 3-a second metal oxide semiconductor thin film; 4-a first metal oxide semiconductor thin film; a 5-graphene film; 6-noble metal nanoparticles.
Detailed Description
In order to make the implementation of the present invention more clear, the following detailed description will be given with reference to the accompanying drawings.
The application provides a noble metal modified composite gas sensor which sequentially comprises a substrate layer 1, an electrode layer 2, a metal oxide semiconductor film layer and a response layer from bottom to top, wherein the metal oxide semiconductor film layer comprises a first metal oxide semiconductor film 4 and a second metal oxide semiconductor film 3, and the response layer comprises a graphene film 5 and noble metal nano particles 6, as shown in figure 1. The thickness of the base layer 1 varies depending on the specific application environment, and specifically, the thickness of the base layer 1 is 0.5mm to 1.0mm, and the thickness of the base layer 1 in this embodiment is 0.625mm. The top view shape of the substrate layer 1 along the vertical direction can be any shape, the size can support other layer structures, and preferably, the top view shape of the substrate layer 1 along the vertical direction is rectangular, so that the preparation is convenient; the dimensions of the gas sensor of the present application are dependent on the application requirements, in particular the dimensions of the gas sensor are in the order of centimeters or millimeters. The base layer 1 is made of aluminum oxide, and the aluminum oxide is hard and resistant to high temperature, so that the base layer can play a role in supporting and protecting other parts, and meanwhile, the gas sensor is aged at high temperature due to the high temperature resistance so as to enhance the stability of the gas sensor; in addition, the electrode layer 2 is conveniently prepared on the substrate layer 1 by etching, specifically, the surface of the electrode layer is plated with electrode materials, and then the corresponding electrode structure is etched, and the electrode structure can be directly inlaid on the substrate layer 2 during preparation.
The electrode layer 2 comprises three electrodes which are of a double-negative electrode structure, are respectively and fixedly arranged at two sides and the middle position of the substrate layer 1, are mutually parallel and are not in contact with each other, one end of the external circuit is connected with the substrate layer 1 in a protruding way, the protruding distance is 0.1-0.5cm, the external circuit is convenient to connect with the external circuit, and the rest electrodes are all arranged on the substrate layer 1. As shown in fig. 1, the electrodes at the middle position are anodes, the two electrodes at the two sides are cathodes, and are fixedly arranged at the two sides of the electrode layer 2, the distance between the two cathodes and the anode at the middle position needs to be determined according to the size of the gas sensor, specifically, the distance between the two cathodes and the anode at the middle position is 0.5cm-1.0cm, the distances between the two cathodes and the anode at the middle position can be equal or unequal, preferably, the distances between the two cathodes and the anode at the middle position are equal, more preferably, the distances between the two cathodes and the anode at the middle position are 0.5cm, so that the symmetry of the sensor is better, the electrochemical reactions at the two cathodes tend to be consistent, and then the resistance change conditions are consistent, so that the detected resistance change comes from the influence of the gas to be detected, and the sensor is beneficial to improving the sensitivity, accuracy and stability. The three electrodes are made of noble metal platinum (Pt) and are all interdigital electrodes, and the interdigital electrodes can rapidly and sensitively capture weak resistance change of the metal oxide semiconductor film. As shown in FIG. 2, the interdigital electrode of the application consists of the finger electrodes which are arranged periodically, specifically, the thickness of the interdigital electrode is 5 μm-10 μm, preferably, the thickness of the interdigital electrode is 5 μm, and the interdigital width is 30nm-150nm, so that the interdigital electrode is in full contact with the metal oxide semiconductor film layer, the contact resistance between the interdigital electrode and the metal oxide semiconductor film layer is reduced, and the resistance change detected by an external circuit connected with the interdigital electrode is all from the response of gas, thereby improving the accuracy of gas sensing.
The metal oxide semiconductor thin film layer includes a first metal oxide semiconductor thin film 4 and a second metal oxide semiconductor thin film 3. The first metal oxide semiconductor thin film 4 is disposed over the positive electrode of the electrode layer 2 while completely covering the middle positive electrode and being in close contact with the positive electrode, thus reducing contact resistance and making the detection sensitivity higher. The two second metal oxide semiconductor films 3 are respectively arranged above the two cathodes of the electrode layer 2, and simultaneously, the cathodes right below the two second metal oxide semiconductor films are completely covered and are in close contact with the cathode electrodes, so that the contact resistance can be reduced, and the detection sensitivity is higher; the thickness and the size of the two second metal oxide semiconductor films 3 can be the same or different, preferably, the thickness and the size of the two second metal oxide semiconductor films 3 arranged right above the two cathodes are the same, and the electrode structure of the two cathodes is combined, so that the electrochemical reaction degree in the two second metal oxide semiconductor films 3 is the same, the resistance change of the two second metal oxide semiconductor films 3 is the same, and the sensing accuracy and the accuracy of the sensor are higher due to the same resistance change; the two second metal oxide semiconductor thin films 3 are also made to coincide with the positive and negative electrode order of the first metal oxide semiconductor thin film 4. Preferably, the positive electrode is arranged right below the geometric center of the first metal oxide semiconductor film 4, and the two negative electrodes are respectively arranged right below the geometric center of the second metal oxide semiconductor film 3, so that the sensor has higher stability and longer service life due to better symmetry.
The thickness of the first metal oxide semiconductor film 4 and the thickness of the second metal oxide semiconductor film 3 are the same and are 10 μm to 15 μm, and the two second metal oxide semiconductor films 3 are communicated through the first metal oxide semiconductor film 4, so that a space charge region can be formed in a contact region of the first metal oxide semiconductor film 4 and the second metal oxide semiconductor film 3 to increase the resistance change of the gas sensor, thereby improving the sensitivity of the gas sensor. The thicknesses of the first metal oxide semiconductor film 4 and the second metal oxide semiconductor film 3 are the same, and the lengths of the first metal oxide semiconductor film 4 and the second metal oxide semiconductor film 3 in the direction perpendicular to the paper surface are equal when the first metal oxide semiconductor film 4 and the second metal oxide semiconductor film 3 are rectangular in plan view, so that the first metal oxide semiconductor film 4 and the second metal oxide semiconductor film 3 are fully contacted, the contact boundary between the first metal oxide semiconductor film and the second metal oxide semiconductor film is long, the preparation is convenient, the space charge area formed at the contact boundary is large, and the sensitivity of the sensor is improved.
The materials of the first metal oxide semiconductor film 4 and the second metal oxide semiconductor film 3 are selected according to the gas to be measured, and specifically, may be simple metal oxides such as zinc oxide, tin oxide, iron oxide, copper oxide, or may be multi-element metal oxides such as iron molybdate and sodium bismuth molybdate. In the application, the materials of the first metal oxide semiconductor film 4 and the second metal oxide semiconductor film 3 are different metal oxide semiconductors, namely, the material of the first metal oxide semiconductor film 4 is a first metal oxide semiconductor, the material of the second metal oxide semiconductor film 3 is a second metal oxide semiconductor, wherein the fermi level of the second metal oxide semiconductor is higher than that of the first metal oxide semiconductor, so that electrons in the second metal oxide semiconductor can flow to the first metal oxide semiconductor; forming a space charge region at the contact boundary of the first metal oxide semiconductor film 4 and the second metal oxide semiconductor film 3, wherein the concentration of carriers in the space charge region is low due to the action of an electric field in the space charge region, and the conductivity is low, so that the sensor presents high resistance characteristics; meanwhile, the concentration of electrons in the first metal oxide semiconductor is larger, so that more oxygen molecules in the air participate in the reduction reaction, the change of the resistance of the gas sensor is increased, and finally the detection sensitivity is further improved. Specifically, the first metal oxide semiconductor in the present application may be tungsten disulfide, and the second metal oxide semiconductor may be titanium dioxide, which is suitable for detecting a reducing gas such as ethanol, acetone, or the like. The first metal oxide semiconductor thin film 4 and the second metal oxide semiconductor thin film 3 may be prepared by screen printing, spin coating, dipping, pulling, CVD, sputtering, transfer printing, or the like.
The response layer comprises a graphene film 5 and noble metal nano particles 6, and the gas sensor provided by the invention interacts with external gas to be detected, air and an optical field through the response layer. The graphene film 5 is fixedly arranged on one side, far away from the electrode layer 2, of the first metal oxide semiconductor film 4, and the fluffy porous structure of the graphene film 5 is favorable for adsorbing more air and gas molecules to participate in reaction, so that the resistance change of the gas sensor is increased, and the detection sensitivity is improved. The area and the size of the graphene film 5 are the same as those of the first metal oxide semiconductor film 4, when the size of the graphene film 5 is too small, a part of the first metal oxide semiconductor film 4 can be exposed in air and gas to be detected, and the first metal oxide semiconductor film 4 at the exposed part can not effectively participate in the sensing process due to the fact that the graphene film 5 has no adsorption effect on the air and the gas to be detected; when the size of the graphene film 5 is too large, due to strong absorption, part of the noble metal nano particles 6 on the second metal oxide semiconductor film 3 cannot be illuminated, so that a plasmon effect cannot be generated, and finally the detection sensitivity is reduced.
The two second metal oxide semiconductor films 3 are provided with noble metal nano particles 6 at the side far away from the electrode layer 2, the noble metal nano particles 6 are made of noble metal materials such as gold Au, silver Ag, platinum Pt and the like, and the particle size is 10nm-50nm, so that under the illumination condition, surface plasmon resonance is generated on the surfaces of the noble metal nano particles 6, a strong electric field is generated on the surfaces of the noble metal nano particles 6, hot electrons generated by strong local electric field excitation are transferred to the second metal oxide semiconductor films 3 from the surfaces of the noble metal nano particles 6, the thickness of a space charge region between the first metal oxide semiconductor and the second metal oxide semiconductor is increased, and the resistance change of the gas sensor is more severe, so that the sensitivity of the gas sensor is higher. In addition, the strong electric field on the surface of the noble metal nano-particles 6 can enable gas molecules to be more easily adsorbed on the surface of the first metal oxide semiconductor film 4 by the graphene film 5, so that the oxidation-reduction reaction intensity is higher, and the sensitivity of the gas sensor is improved. The graphene film 5 may be prepared by a chemical vapor deposition method, and the noble metal nanoparticles may be prepared by an in-situ reduction method.
When the gas sensor is applied, the surface of the gas sensor is irradiated by light, and two cathodes and one anode of the electrode layer 2 are respectively connected with the cathode and the anode of an external power supply. Since the fermi level of the second metal oxide semiconductor is higher than that of the first metal oxide semiconductor, the first metal oxide semiconductor thin film 4 corresponds to a p-type semiconductor, the second metal oxide semiconductor thin film 3 corresponds to an n-type semiconductor, the test current flows in from the positive electrode of the electrode layer 2, and flows out from the two negative electrodes, namely, the test current flows in from the first metal oxide semiconductor thin film 4, the second metal oxide semiconductor thin film 3 flows out, the space charge region widens with the increase of the externally applied bias voltage, the carrier concentration in the space charge region is very low, and the conductivity is very low, so that the sensor exhibits high resistance characteristics. Under the action of the externally applied bias voltage, more electrons flow into the first metal oxide semiconductor film 4 from the second metal oxide semiconductor film 3, so that the concentration of electrons in the first metal oxide semiconductor film 4 is larger, more oxygen in the air can participate in oxidation-reduction reaction, and meanwhile, the electron exchange degree between the gas to be detected and the first metal oxide semiconductor film 4 is stronger, so that the gas sensor has higher sensitivity.
The light irradiates the surface of the gas sensor, the surface of the noble metal nano-particle 6 generates surface plasmon resonance, a strong electric field is generated on the surface of the noble metal nano-particle 6, hot electrons excited by the strong electric field flow from the noble metal nano-particle 6 to the second metal oxide semiconductor film 3. Since the fermi level of the second metal oxide semiconductor is higher than that of the first metal oxide semiconductor, hot electrons flow from the second metal oxide semiconductor thin film 3 to the first metal oxide semiconductor thin film 4 through the space charge region at the contact, so that the concentration of electrons in the first metal oxide semiconductor thin film 4 is high, and in addition, electron holes are separated in the space charge region, so that the resistance monitored by the electrode is drastically changed. The electrons with higher concentration can generate sufficient oxidation reaction with oxygen in the air, so that more oxygen anions can be generated.
Firstly, the gas sensor is contacted with air, the graphene film 5 is of a porous structure and has strong adsorption effect, a large number of oxygen molecules are adsorbed on the surface of the first metal oxide semiconductor film 4, and the oxygen molecules capture electrons in the first metal oxide semiconductor film 4 to generate oxidation reaction so as to generate oxygen anions; the high concentration of electrons in the first metal oxide semiconductor film 4 enables more electrons to be captured by oxygen molecules, so that more oxygen in the air participates in oxidation-reduction reaction, and meanwhile, the intensity of the oxidation reaction is enhanced, more oxygen anions are generated, preparation is made for reduction reaction, and the more the generated oxygen anions are, the higher the detection sensitivity of the gas sensor is.
Then the gas sensor is contacted with the gas to be detected, through the adsorption of the graphene film 5 with a porous structure, the molecules of the gas to be detected and the oxygen anions on the surface of the first metal oxide semiconductor film 4 undergo a reduction reaction, the oxygen anions are reduced into oxygen to release electrons, and the released electrons return to the first metal oxide semiconductor film 4 again, so that the concentration of the electrons in the sensor is greatly increased, the resistance monitored by the electrode is greatly reduced, and the type and the concentration of the gas to be detected are judged. The degree of the reduction reaction of different types of gases to be detected and oxygen anions is different, the number and the speed of electrons released in the reduction process are different, and the resistance change is different; the reaction degree of the gas to be detected and the oxygen anions of the same type and different concentrations is different, the speed and the quantity of electrons released in the reaction process are different, and the change of the resistance is also different, so that the type and the concentration of the gas to be detected can be judged through the change of the resistance.
The gas sensor is firstly contacted with the air, so that oxygen molecules in the air and electrons of the first metal oxide semiconductor film 4 are subjected to oxidation reaction to generate a large amount of oxygen anions, and meanwhile, electrons in the first metal oxide semiconductor film 4 are consumed in the process, so that the resistance value of the sensor is increased; the gas sensor is contacted with the gas to be detected, so that reduction reaction is generated between molecules of the gas to be detected and a large amount of generated oxygen anions, the concentration of the oxygen anions is high, the reduction reaction is sufficient, electrons are released in the process, the concentration of electrons in the first metal oxide semiconductor film 4 is increased, the resistance value of the sensor is suddenly reduced, and the reduction reaction between the oxygen anions and the molecules of the gas to be detected is sufficient, so that the resistance value of the sensor is suddenly reduced, and the sensitivity of the gas sensor is high. Since the process does not require that the gas molecules to be measured have a high activity, the sensor of the application has a high sensitivity at low temperatures, of course, and in particular, the low temperature of the application refers to 25-100 ℃.
The first metal oxide semiconductor film 4 and the second metal oxide semiconductor film 3 in the present application are stacked by nano materials, wherein the nano materials comprise nano sheets, nano spheres, nano rods, etc., and the surfaces of the first metal oxide semiconductor film 4 in the present application are all the surfaces of the nano materials. The specific surface area of the nano material is higher, so that the air and the gas to be detected are in more sufficient contact with the first metal oxide semiconductor film 4, so that the oxidation reaction and the reduction reaction are more sufficient, the working temperature of the gas sensor can be reduced, and the gas sensor is more suitable for gas sensing at low temperature.
The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (5)
1. The noble metal modified composite gas sensor is characterized by comprising a basal layer, an electrode layer, a metal oxide semiconductor film layer and a response layer from bottom to top in sequence, wherein the electrode layer comprises three electrodes which are fixedly arranged on the basal layer and are not contacted with each other, the three electrodes are arranged in parallel in the middle and at two sides of the basal layer, the middle position is an anode, the two sides are two cathodes, the distances between the two cathodes and the middle anode are equal to 0.5cm, the metal oxide semiconductor film layer is fixedly arranged at one side of the electrode layer far away from the basal layer, the metal oxide semiconductor film layer comprises a first metal oxide semiconductor film and two second metal oxide semiconductor films, the first metal oxide semiconductor films completely cover the anode, the two second metal oxide semiconductor films completely cover the two cathodes, the first metal oxide semiconductor films can be lower than the second metal oxide semiconductor films, the second metal oxide semiconductor films have the same thickness, the second metal oxide semiconductor films are far away from the graphene oxide semiconductor films, the graphene oxide semiconductor films are the same in size, the graphene oxide semiconductor films are provided with the same side, and precious metal nano particles are fixedly arranged on one side of the two second metal oxide semiconductor films, which is far away from the electrode layer.
2. The noble metal modified composite gas sensor of claim 1, wherein each of the three electrodes is comprised of a periodic array of finger electrodes.
3. The noble metal modified composite gas sensor of claim 2, wherein the thickness of each of the three electrodes is 5 μm to 10 μm.
4. A precious metal modified composite gas sensor according to claim 3, wherein the substrate layer is aluminum oxide.
5. The noble metal-modified composite gas sensor of claim 4, wherein the noble metal nanoparticle material is gold or silver or platinum.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN111239207A (en) * | 2020-03-03 | 2020-06-05 | 电子科技大学中山学院 | Composite structure gas sensor composed of metal oxide porous film and holes |
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| CN111239207A (en) * | 2020-03-03 | 2020-06-05 | 电子科技大学中山学院 | Composite structure gas sensor composed of metal oxide porous film and holes |
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