CN102081069B - Carbon nanotube film three-electrode sensor and method for detecting concentration of single gas by using same - Google Patents

Abstract

The invention discloses a carbon nanotube film three-electrode sensor and a method for detecting single gas concentration, wherein the sensor comprises a first electrode, a second electrode and a third electrode which are sequentially distributed, the first electrode is provided with air holes, and the inner surface of the first electrode is bonded with a substrate distributed with a carbon nanotube film; the center of the second electrode is provided with a lead-out hole; a blind hole is formed in the surface of the third electrode; the three electrodes are isolated from each other. The method comprises the following steps: 1) three sensors with different inter-polar distances are arranged to respectively detect the gas concentration, the temperature and the humidity; 2) applying a voltage across the electrodes; 3) measuring ion flow values of the sensors; 4) the measured value and the single gas concentration, temperature and humidity calibration value form a sample, and the sample and the interpolation sample construct a gas concentration measurement database; 5) constructing a data fusion instrument and establishing a single gas concentration measurement model; 6) the actual measurement value of the sensor is input into the measurement model to obtain the accurate measurement value of the concentration of the single gas. The sensor has the advantages of high gas detection sensitivity, good linearity and high accuracy.

Description

Carbon nanotube film three-electrode sensor and method for detecting single gas concentration

technical field

The invention relates to the field of gas sensing, in particular to a three-electrode sensor based on carbon nanotube film and gas discharge principle and a method for detecting single gas concentration.

Background technique

With the urgent need of gas detection in all walks of life and the development of nanotechnology, nanosensors have made great progress. Especially with the discovery of carbon nanotubes at the end of the 20th century, carbon nanotubes have shown attractive application prospects in the fields of gas, temperature and humidity detection. The carbon nanotube film two-electrode sensor among carbon nanotube gas, temperature and humidity sensors has become a research hotspot in the field of gas, temperature and humidity detection due to its advantages of high detection sensitivity, wide detection gas range and fast response. Carbon nanotube film two-electrode gas sensor is based on the principle of gas discharge, which overcomes the shortcomings of other types of carbon nanotube gas sensors that are saturated and poisoned in the measured gas, and has a wider gas concentration measurement range and a wider range of gas types to be measured. Gas-sensitive, temperature-sensitive, and humidity-sensitive sensors made of carbon nanotubes as sensitive materials have irreplaceable advantages of conventional sensors: First, carbon nanotubes have a large specific surface area, which can greatly improve the overall size of the sensor when the overall size of the sensor is small. The area of the electrode; the second is based on the nanoscale tip curvature radius of the carbon nanotubes, which greatly reduces the operating voltage of the sensor, and obtains a very strong electric field strength near the tip of the carbon nanotubes, ionizing the measured gas at a low voltage; The size of the sensor is greatly reduced, and the dynamic response is fast. Therefore, it has broad development prospects in biology, chemistry, machinery, aviation, military affairs, and anti-terrorism.

Existing carbon nanotube film two-electrode sensors include carbon nanotube film two-electrode sensors disclosed by professors Liu Junhua, Zhang Yong, Li Xin, Zhu Changchun, etc. of Xi'an Jiaotong University at the 14th IVMC International Vacuum Microelectronics International Conference in 2001. Electrode gas sensor (shown in Figure 1). After the sensor works, because the space charge is difficult to diffuse after the discharge between the electrodes, the sensor is difficult to return to the initial state, and the sensor breakdown voltage, breakdown current and gas concentration show a multi-valued relationship (Figure 2, Figure 3), and the gas concentration cannot be determined. Concentration is measured. Professor Nikhil Koratkar and Pulickel M Ajayan of Rensselaer Polytechnic Institute in the United States developed a carbon nanotube film anode two-electrode gas sensor. The breakdown voltage of the sensor shows a nonlinear relationship with the gas concentration, and the linear error between the breakdown discharge current and the gas concentration is large; the discharge voltage and discharge current are large; and the carbon nanotube thin film anode cannot measure a single gas. Professor Hui Guohua and Professor Chen Yuquan from the School of Biomedical Engineering and Instrument Science of Zhejiang University developed a carbon nanotube film cathode two-electrode gas sensor under the condition of 120 micron electrode spacing, and studied the discharge characteristics of the sensor in three single gases , due to low sensitivity, does not constitute a gas sensor for measuring concentration.

Therefore, the current research on carbon nanotube thin film electrode sensors sensitive to various single gases and methods for detecting the concentration of single gases has become a technical problem to be solved urgently.

Contents of the invention

One of the purposes of the present invention is to provide a carbon nanotube film three-electrode sensor, which divides the output current of the traditional carbon nanotube film two-electrode sensor into electron flow and ion flow, and establishes the ion flow collected by the collector electrode of the three-electrode sensor of the present invention. The single-value corresponding relationship between flow and single gas concentration, temperature and humidity overcomes the multi-value non-linear problem of gas-sensing characteristics and humidity-sensing characteristics of carbon nanotube film two-electrode sensor. The sensor has the advantages of simple structure, low cost and high gas detection sensitivity.

Another object of the present invention is to provide a method for detecting the concentration of a single gas based on a carbon nanotube thin film three-electrode sensor. The sensor array is composed of carbon nanotube thin film three-electrode sensors with different electrode spacings to measure the single gas concentration and gas temperature to be measured respectively. and humidity; the concentration measurement method requires a simple hardware structure, can measure any single gas, and adopts a data fusion algorithm to detect gas with high accuracy.

The purpose of the present invention is achieved through the following technical solutions.

The carbon nanotube film three-electrode sensor is characterized in that it includes three first electrodes, second electrodes and third electrodes distributed sequentially from top to bottom, and the first electrode is bonded with carbon nanotubes distributed on the inner surface. The substrate of the film is composed of electrodes with air holes; the second electrode is composed of a lead-out plate with a lead-out hole in the center; the third electrode is composed of a collector with a blind hole on the plate surface; the three electrodes are respectively insulated The struts are isolated from each other.

Structural feature of the present invention is also in:

The electrode distance between two adjacent electrodes among the three electrodes is 30-250 μm;

The facing area of the first electrode and the second electrode plate is 0.01-17mm ² , and the facing area of the second electrode and the third electrode plate is 0.01-190mm ² .

The electrode surface of the first electrode has 1 to 4 air holes, and a carbon nanotube film is attached to the carbon nanotube film substrate bonded to the inner surface of the electrode;

There are 1 to 4 ventilation holes in the center of the lead-out pole of the second electrode;

The collector blind hole of the third electrode corresponds to the lead-out hole of the second electrode, and the number of blind holes is 1-4.

The present invention also provides a method for detecting a single gas concentration based on a carbon nanotube film three-electrode sensor, the method comprising the following steps:

(1) Choose a carbon nanotube film three-electrode sensor with the electrode spacing of two adjacent electrodes set at 30-250 μm among the three electrodes;

(2) Place three carbon nanotube film three-electrode sensors with different electrode spacings as the carbon nanotube film three-electrode single gas sensor, carbon nanotube film three-electrode temperature sensor and carbon nanotube film three-electrode humidity sensor respectively. In an atmosphere containing a single gas to be measured;

(3) The first electrode of the three carbon nanotube film three-electrode single gas sensor, the carbon nanotube film three-electrode temperature sensor and the carbon nanotube film three-electrode humidity sensor are loaded with a voltage of 0V, and the second electrode is loaded with a voltage of 2 ~200V, the loading voltage of the third electrode is 1~180V;

(4) Within the measurement range of single gas concentration, temperature and humidity to be measured, corresponding to different concentration, temperature and humidity calibration values, respectively measure the gas discharge ion current values output by all sensors in step (2);

(5) Combine all the sensor output ion current values measured in the concentration, temperature and humidity measurement ranges in step (4) with the corresponding single gas concentration, temperature and humidity calibration values to form different experimental calibration samples, and then use Segmented interpolation technology interpolates the experimental calibration samples, obtains interpolation data, obtains interpolation samples, and builds a single gas concentration measurement database based on all samples including experimental calibration samples and interpolation samples;

(6) Using data fusion technology, build a data fusion instrument, establish a measurement model of a carbon nanotube film three-electrode single gas sensor, a carbon nanotube film three-electrode temperature sensor and a carbon nanotube film three-electrode humidity sensor; measure with a single gas concentration The data in the database is used as the input sample and the expected output sample of the data fusion instrument, and different data within the range are used as the training sample and the test sample of the data fusion instrument for training and testing. When the test results meet the requirements of the measured error, the data fusion The instrument outputs a single gas sensor concentration accurate measurement model;

(7) Input the ion current value output by the carbon nanotube film three-electrode single gas sensor, temperature sensor and humidity sensor into the accurate measurement model of single gas concentration obtained in step (6), and the model outputs the accurate measurement value of single gas concentration .

The inventive method is also characterized in that:

In the carbon nanotube film three-electrode sensor, the potential of the second electrode is higher than the potential of the first electrode, and the potential of the third electrode is lower than the potential of the second electrode and higher than the potential of the first electrode.

The establishment of a single gas concentration measurement database is to form a database with experimental calibration data and interpolation data, use the ion current value output by each sensor and its interpolation data as an input sample, and use a single gas concentration, temperature and humidity calibration value and its interpolation data as an input sample. Expected output sample.

Based on the measurement method of single gas concentration detected by carbon nanotube film three-electrode sensor, the sensor array is composed of carbon nanotube film three-electrode sensors with different electrode spacing to measure the single gas concentration, temperature and humidity respectively; powered by sensor voltage source; powered by pA The output of the sensor is detected by the level current measurement system; the electrode spacing is adjusted, the electrode voltage is adjusted, and the sensor calibration experiment is carried out in the temperature and humidity environment in the single gas to be tested; the experimental calibration data is interpolated based on the segmental interpolation technology to obtain the interpolation data ;Compose all the data including the experimental calibration data and interpolation data into a single gas concentration measurement database, and obtain the single-value gas-sensing characteristics, single-value temperature-sensing characteristics and single-value humidity-sensing characteristics of the single gas to be measured; according to the single-gas concentration measurement database Based on the data fusion technology, the influence of temperature and humidity is eliminated, and an accurate measurement model of the concentration of a single gas sensor is established; the output of the sensor array during actual measurement is input into the single gas concentration measurement model in real time, and the actual measurement of the concentration of a single gas can be obtained result. The single gas concentration measurement method overcomes the multi-valued non-linear problem of the carbon nanotube film two-electrode sensor's gas-sensing characteristics and humidity-sensing characteristics. It has high accuracy and is suitable for popularization.

The single gas concentration detection method of the present invention can realize the concentration measurement of a single gas with an accuracy of 1%. Compared with the concentration detection method of the traditional three-electrode detector used in the existing ionization detector chromatograph, the new concentration detection method uses the carbon nanotube film as the electrode, and the sensor is sensitive to all single gases including flammable and explosive Toxic gases have high sensitivity and 1% concentration measurement accuracy, so the measurement process overcomes the problem that the chromatograph needs to replace different types of detectors for different gases. Moreover, the carbon nanotube three-electrode sensor can reduce the working voltage of the sensor from the high voltage of 600 volts of the ionization detector to a safe and practical range below 200 volts with the nanoscale tip curvature radius of the carbon nanotubes. The new single gas concentration measurement method of the present invention integrates sensor array technology with different pole spacing, pA level current measurement technology, segmental interpolation technology and data fusion technology, can eliminate the influence of temperature and humidity, and can realize the single gas concentration. Measure accurately.

Description of drawings

Fig. 1 is a schematic diagram of the structure of a carbon nanotube film cathode two-electrode sensor.

Fig. 2 shows the multi-valued nonlinear gas sensing characteristics of the breakdown voltage and gas concentration of the carbon nanotube film two-electrode gas sensor in the prior art.

Fig. 3 is the non-linear multi-valued gas sensing characteristics of the breakdown current and gas concentration of the carbon nanotube film two-electrode gas sensor in the prior art.

Fig. 4 is a schematic diagram of the structure of the carbon nanotube film three-electrode sensor of the present invention.

Fig. 5 is a side view of the stereoscopic structure of the carbon nanotube film three-electrode sensor of the present invention.

Fig. 6 is the single-value relationship between the gas discharge ion current and the gas concentration output by the carbon nanotube thin film three-electrode sensor in the single gas hydrogen of the present invention.

Fig. 7 is the single-value relationship between the gas discharge ion current and the gas concentration output by the carbon nanotube thin film three-electrode sensor of the present invention in a single gas acetylene.

Fig. 8 is the single-value relationship between the gas discharge ion current and the gas concentration output by the carbon nanotube film three-electrode sensor in the single gas nitric oxide of the present invention.

In the figure: 1, the first electrode; 2, the second electrode; 3, the third electrode; 4, the electrode provided with air holes; 5, the carbon nanotube film substrate; 6, the carbon nanotube film; 7, the insulating support.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

Example 1

As shown in Figure 4 and Figure 5, the carbon nanotube thin film three-electrode sensor consists of three electrodes that are stacked from top to bottom in sequence, and the three stacked electrodes are respectively the first electrode 1 and the second electrode 2 and the third electrode 3, the first electrode 1 is composed of a substrate 5 with a carbon nanotube film 6 distributed on the inner surface and an electrode 4 with air holes; The third electrode 3 is composed of a collector with blind holes on the surface of the electrode plate; the three electrodes are separated from each other by insulating pillars 7 .

In the carbon nanotube thin film three-electrode sensor embodiment shown in Fig. 4, there are 2 vent holes on the electrode surface of the first electrode 1, and the vent holes are circular; The tube film substrate 5 is distributed with a carbon nanotube film 6, and the carbon nanotube tube mouth is downward. A lead-out hole is provided in the center of the second electrode 2, and the lead-out hole is circular. The collector blind hole of the third electrode 3 corresponds to the lead-out hole of the second electrode. Fig. 4 and Fig. 5 show an embodiment in which a blind hole is provided and the blind hole is a cylindrical structure. The insulating pillars 7 are respectively arranged between the carbon nanotube film substrate 5 and the second electrode 2, and between the second electrode 2 and the third electrode 3, that is, the insulating pillars 7 are distributed on the carbon surface of the second electrode 2 facing the first electrode 1. The two sides of the surface of both ends of the nanotube film substrate and the two sides of the inner surface of the third electrode 3 .

The present invention is provided with the plate surface of the electrode 4 with air holes and the carbon nanotube film base 5 all adopts silicon chip material to make; The carbon nanotube film 6 is grown on top of the carbon nanotube film 6, or the carbon nanotube film 6 is screen-printed. Both the second electrode 2 and the third electrode 3 are made of silicon wafers. Metal films are provided on the inner surfaces of the electrode 4 and the third electrode 3 provided with air holes, and on both sides of the second electrode 2 .

There are 2 air holes on the electrode in the first electrode 1 of the present invention, which is convenient for the gas to be detected to enter the electrode gap; the silicon chip base of the carbon nanotube film has conductivity, and is firmly bonded to the inner surface of the first electrode; The extraction hole of the electrode 2 and the collector of the third electrode 3 can collect the positive ion flow generated by gas ionization. Between the first electrode 1 and the second electrode 3, between the second electrode 2 and the third electrode 3 are isolated from each other by insulating pillars 7; the gas to be measured enters the gap between two adjacent electrodes of the sensor through the gap between the peripheral electrodes of the sensor .

When the carbon nanotube film three-electrode sensor with the above structure measures the concentration of a single gas, the potential of the second electrode is higher than that of the first electrode, and the potential of the third electrode is lower than the potential of the second electrode and higher than that of the first electrode. The second electrode forms an electron flow loop with the first electrode, and the third electrode forms an ion flow loop with the first electrode, so as to separate the electron flow from the ion flow. The relationship between the ion flow output by the carbon nanotube thin film three-electrode sensor and the concentration of a single gas, gas temperature and humidity, based on a certain voltage applied to the second electrode, presents a single value relationship (Figure 6~Figure 8). Through segmental interpolation and data fusion technology, the measurement accuracy of single gas concentration is 1%. The carbon nanotube film three-electrode sensor array technology with different pole spacing, pA level current measurement technology, segmental interpolation technology and data fusion technology are the characteristics of the concentration measurement method of the present invention.

The method for detecting the concentration of a single gas by the carbon nanotube thin film three-electrode sensor of the present invention will be further described through a specific example.

Using a carbon nanotube film three-electrode sensor with a fixed electrode spacing, the single-valued gas-sensing characteristics of a single gas hydrogen (as shown in Figure 6) were experimentally obtained. The ion current data output by the sensor was input into the single-gas concentration measurement model established by data fusion, and obtained A single gas hydrogen concentration measurement with an accuracy of less than 1% was achieved.

In the example of detecting the concentration of hydrogen in a single gas by the carbon nanotube film three-electrode sensor shown in Figure 6, the experimental environment conditions are temperature 27.0°C, relative humidity 22.6%RH, and atmospheric pressure 93.3KPa. The distance between the first electrode 1 and the second electrode 2 of the single gas sensor, and the distance between the second electrode 2 and the third electrode 3 are all 100 μm; the distance between the adjacent electrodes of the carbon nanotube film three-electrode sensor for temperature monitoring is 170 μm ; The carbon nanotube thin film three-electrode sensor used for monitoring the humidity has an electrode spacing of 200 μm and 100 μm respectively between adjacent electrodes. In the three carbon nanotube film three-electrode sensors, the facing area of the first electrode 1 and the second electrode 2 is 17 mm ² , and the facing area of the second electrode 2 and the third electrode 3 is 190 mm ² . The cathode voltage of the first electrode 1 of the single gas sensor is 0V, the loading voltage of the second electrode 2 is 80V, and the loading voltage of the third electrode 3 is 10V; the voltages of the first, second, and third electrodes of the temperature sensor are 0V, 70V, 10V; the voltages of the first, second and third electrodes of the humidity sensor are 0V, 90V and 10V respectively. As the hydrogen concentration increases, the ion flow collected by the collector of the single gas sensor decreases, and the relationship between the ion flow and the hydrogen concentration shows a single-valued decrease; the sensitivity characteristics of the temperature and humidity sensors are similar to those of the single gas sensor. In the range of 0-400ppm hydrogen concentration, 11 sets of experimental calibration data were obtained. The ion current values of the three sensors are used as input samples, and the hydrogen concentration calibration value is used as the expected output sample data. Use linear interpolation to interpolate the data of 11 sets of experimental calibration samples, and interpolate at equal intervals at 10ppm within the hydrogen concentration range of 0~400ppm, obtain 39 sets of interpolation data, and form a database with 11 sets of experimental calibration data; select 39 sets of interpolation data A total of 41 sets of data and 2 sets of experimental calibration data were used as training samples, and 9 sets of experimental calibration data different from the training samples were selected as test samples, input into the data fusion instrument, and the concentration measurement model of single gas hydrogen was obtained through training and testing. The linearity of the single gas hydrogen concentration measurement model is 0.31%, and the maximum quoted error of the test results of the 9 groups of test samples is 0.37%, reaching a single gas hydrogen concentration measurement accuracy of 1%.

Example 2

The basic structure of the sensor of this embodiment is the same as that of Embodiment 1, the difference is:

Among the three electrodes of the carbon nanotube film three-electrode acetylene sensor, the electrode spacing between two adjacent electrodes is fixed at 200 μm, the first electrode 1 has two air holes, the second electrode 2 has one lead-out hole, and the third electrode 3 is 1 blind hole.

Using the carbon nanotube thin film three-electrode acetylene sensor with a fixed electrode spacing, the single-valued gas-sensing characteristics of a single gas acetylene were experimentally obtained (as shown in Figure 7). A single gas acetylene concentration measurement with an accuracy of less than 1% was obtained.

In the embodiment of the carbon nanotube film three-electrode sensor detecting the concentration of a single gas acetylene shown in FIG. 7 , the experimental environment conditions are temperature 26.5°C, relative humidity 23.0%RH, and atmospheric pressure 93.7KPa. The distance between the first electrode and the second electrode of the sensor, and the distance between the second electrode and the third electrode are all 200 μm; the distance between the adjacent electrodes of the carbon nanotube film three-electrode sensor for monitoring temperature is 170 μm; The distance between adjacent electrodes of the nanotube film three-electrode sensor is 200 μm and 100 μm, respectively. In the three carbon nanotube film three-electrode sensors, the facing area of the first electrode 1 and the second electrode 2 is 17 mm ² , and the facing area of the second electrode 2 and the third electrode 3 is 190 mm ² . The cathode voltage of the first electrode of the single gas sensor is 0V, the loading voltage of the second electrode lead-out electrode is 80V, and the loading voltage of the third electrode collector is 10V; the voltage of the first, second, and third electrodes of the temperature sensor are 0V, 70V, and 10V respectively; humidity The voltages of the first, second and third electrodes of the sensor are 0V, 90V and 10V respectively. As the concentration of acetylene increases, the ion flow collected by the collector decreases, and the relationship between the ion flow and the concentration of acetylene shows a single value decrease; the sensitivity characteristics of temperature and humidity sensors are similar to those of single gas sensors. In the concentration range of 0-30ppm acetylene, 13 sets of experimental calibration data were obtained. The ion current values of the three sensors are used as input samples, and the calibration value of acetylene concentration is used as the expected output sample data. Using linear interpolation to interpolate the data of 13 sets of experimental calibration samples, interpolating with a step size of 0.2ppm in the range of 0~30ppm acetylene concentration, obtaining 151 sets of interpolation data, and forming a database with 13 sets of experimental calibration data; selecting 151 sets of interpolation data A total of 152 sets of data and 1 set of experimental calibration data are used as training samples, 12 sets of experimental calibration data different from training samples and 1 set of experimental calibration data that have been used as training samples, a total of 13 sets of experimental calibration data are used as test samples, and input data fusion instrument , through training and testing, a single gas acetylene concentration measurement model is obtained. The linearity of the single-gas acetylene concentration measurement model is 0.09%, and the maximum quoted error of the test results of the 13 groups of test samples is 0.25%, reaching a single-gas acetylene concentration measurement accuracy of 1%.

Example 3

The basic structure of the sensor of this embodiment is the same as that of Embodiment 1, the difference is:

Among the three electrodes of the carbon nanotube thin-film three-electrode nitric oxide sensor, the electrode spacing between two adjacent electrodes is fixed at 200 μm and 100 μm respectively, the first electrode 1 has 2 air holes, and the second electrode 2 has 1 lead-out hole. and one blind hole for the third electrode 3.

Using the carbon nanotube thin-film three-electrode nitric oxide sensor with a fixed electrode spacing, the single-valued gas-sensing characteristics of a single gas nitric oxide were experimentally obtained (as shown in Figure 8). The nitric oxide concentration measurement model obtained a single gas nitric oxide concentration measurement with an accuracy of less than 1%.

In the embodiment of the carbon nanotube film three-electrode sensor detecting the concentration of nitric oxide in a single gas shown in Fig. 8, the experimental environment conditions are temperature 24.5°C, relative humidity 24.5%RH, and atmospheric pressure 93.4KPa. The distance between the first electrode and the second electrode of the sensor is 200 μm, and the distance between the second electrode and the third electrode is 100 μm; the distance between adjacent electrodes of the carbon nanotube film three-electrode sensor for temperature monitoring is 170 μm; The distance between adjacent electrodes of the carbon nanotube film three-electrode sensor is 200 μm and 100 m, respectively. In the three carbon nanotube film three-electrode sensors, the facing area of the first electrode 1 and the second electrode 2 is 17 mm ² , and the facing area of the second electrode 2 and the third electrode 3 is 190 mm ² . The cathode voltage of the first electrode of the single gas sensor is 0V, the loading voltage of the second electrode lead-out electrode is 130V, and the loading voltage of the third electrode collector is 10V; the voltages of the first, second, and third electrodes of the temperature sensor are 0V, 70V, and 10V respectively; humidity The voltages of the first, second and third electrodes of the sensor are 0V, 90V and 10V respectively. As the nitric oxide concentration increases, the ion current collected by the collector decreases, and there is a single-value decreasing relationship between the ion current and the nitric oxide concentration; the sensitivity characteristics of temperature and humidity sensors are similar to those of single gas sensors. In the range of 0~1208.998ppm nitric oxide concentration, 12 sets of experimental calibration data were obtained. The ion current values of the three sensors are used as input samples, and the calibration value of nitric oxide concentration is used as the expected output sample data. Linear interpolation is used to interpolate the data of 12 groups of experimental calibration samples. Within the concentration range of 0~1208.998ppm, the concentration range of 489.570ppm~828.778ppm is interpolated at 5ppm intervals, and the other intervals are interpolated at equal intervals at 15ppm intervals to obtain 127 sets of interpolation values. Data, and form a database with 12 sets of experimental calibration data; select 118 sets of interpolation data as training samples, and 12 sets of experimental calibration data as test samples, input the data fusion instrument, and obtain a single gas nitric oxide concentration measurement model through training and testing. The linearity of the concentration measurement model was 0.1%, and the maximum quoted error of the test results of the 12 groups of test samples was 0.46%, reaching a concentration measurement accuracy of 1%.

Example 4

The basic structure of this embodiment is the same as that of Embodiment 1, the difference is that the electrode spacing between two adjacent electrodes among the three electrodes of the carbon nanotube film three-electrode sensor is 250 μm and 30 μm respectively, and the first electrode 1 and the second electrode 2 The polar plate facing area is 0.01mm ² , and the polar plate facing area of the second electrode 2 and the third electrode 3 is 0.01mm ² .

There is one vent hole on the electrode surface of the first electrode 1, and the vent hole is quadrilateral, pentagonal or hexagonal; the second electrode 2 has 4 center lead-out holes, and the lead-out holes are quadrilateral, pentagonal or hexagonal ; The number of blind holes in the third electrode 3 is 4, and the blind holes are 3-6 prisms or pyramids.

The detection method of the present embodiment is basically the same as embodiment 1, the difference is:

The cathode voltage of the first electrode of the sensor is 0V, the lead-out pole of the second electrode is loaded with a voltage of 2V, and the collector of the third electrode is loaded with a voltage of 1V.

Example 5

The basic structure of this embodiment is the same as that of Embodiment 1, except that the distance between two adjacent electrodes among the three electrodes is 250 μm and 30 μm respectively, and the facing area of the plates of the first electrode 1 and the second electrode 2 is 10 mm ² , the area of the plate facing the second electrode 2 and the third electrode 3 is 100 mm ² .

There are 4 vent holes on the electrode surface of the first electrode 1, and the vent holes are quadrilateral, pentagonal or hexagonal; the second electrode 2 has 2 central lead-out holes, and the lead-out holes are quadrilateral, pentagonal or hexagonal ; The number of blind holes in the third electrode 3 is 2, and the blind holes are 3-6 prisms or pyramids.

The detection method of the present embodiment is basically the same as embodiment 1, the difference is:

The cathode voltage of the first electrode of the sensor is 0V, the lead-out electrode of the second electrode is loaded with a voltage of 200V, and the collector of the third electrode is loaded with a voltage of 180V.

In the present invention, a sensor array composed of sensors with different pole spacing, a pA level current measurement system to detect sensor output, segmental interpolation and data fusion methods form a new type that can measure various single gases to be measured, has strong anti-interference ability and high accuracy Single gas concentration measurement method. The sensors with different pole spacing in the sensor array can detect the interference effect of temperature and humidity in real time, and directly detect the concentration of a single gas; the pA-level current measurement system can simultaneously detect the pA-level current output by each sensor corresponding to a single gas concentration, temperature and humidity; Segment interpolation and data fusion methods can eliminate temperature and humidity interference, and output a single gas concentration measurement value with high accuracy.

Although the present invention has been described in detail with the above preferred embodiments, the above embodiments are not intended to limit the present invention. Without departing from the technical features and structural scope provided by the technical solution of the present invention, any addition, deformation or replacement of the technical features with the same content in the field shall belong to the protection scope of the present invention.

Claims (4)

1. carbon nano-tube film three electrode sensors, it is characterized in that: comprise three the first electrode, the second electrode and third electrodes that distribute successively from top to bottom, the electrode that described the first electrode is bonded with the substrate of the carbon nano-tube film that distributing by inside surface and is provided with bleeder vent consists of; The second electrode is made of the extraction pole pole plate that the center is provided with fairlead; Third electrode is made of the collector that the plate face is provided with blind hole; These three electrodes are isolated mutually by insulation column respectively;

The die opening of adjacent two electrodes is 100 ~ 200 μ m in described three electrodes; Described the first electrode and the second electrode pad are 0.01 ~ 17mm over against area ², the second electrode and third electrode pole plate are 0.01 ~ 190mm over against area ²

The bleeder vent of the electrode surface of described the first electrode is 2, and the substrate bonding at the electrode inner surface is attached with carbon nano-tube film;

Described the second electrode extraction pole center is provided with 1 fairlead;

Described third electrode collector blind hole is corresponding with the fairlead of the second electrode, and the quantity of blind hole is 1.

2. detect the method for pure gas concentration based on carbon nano-tube film three electrode sensors claimed in claim 1, it is characterized in that the method comprises the steps:

(1) select the die opening of adjacent two electrodes in three electrodes to be set as carbon nano-tube film three electrode sensors of 100 ~ 200 μ m;

Carbon nano-tube film three electrode sensors of three different poles spacings (2) will setting respectively are placed in the atmosphere that contains pure gas to be measured as carbon nano-tube film three electrode pure gas sensors, carbon nano-tube film three electrode temperature sensors and carbon nano-tube film three electrode humidity sensors;

(3) be 0V to the first electrode on-load voltage of three carbon nano-tube films, three electrode pure gas sensors, carbon nano-tube film three electrode temperature sensors and carbon nano-tube film three electrode humidity sensors respectively, the second electrode on-load voltage 2 ~ 200V, third electrode on-load voltage 1 ~ 180V;

(4) in pure gas concentration to be measured, temperature and humidity measurement range, corresponding different concentration, temperature and humidity calibration value, respectively the gas discharge ion flow valuve of all the sensors output in the measuring process (2);

(5) with all the sensors output ion flow valuve that in concentration, temperature and humidity measurement range, records in the step (4), with corresponding pure gas concentration, temperature and humidity calibration value, form different experimental calibration samples, then adopt the piecewise interpolation technology that the experimental calibration sample is carried out interpolation, obtain interpolated data, obtain interpolated sample, and set up pure gas concentration measurement data storehouse according to all samples that comprised experimental calibration sample and interpolated sample;

(6) adopt Data fusion technique, make up the data fusion instrument, set up the measurement model of carbon nano-tube film three electrode pure gas sensors, carbon nano-tube film three electrode temperature sensors and carbon nano-tube film three electrode humidity sensors; With input sample and the desired output sample of the data in the pure gas concentration measurement data storehouse as the data fusion instrument, and train and check as training sample and the test samples of data fusion instrument respectively with data different in the range ability, when assay satisfies the measurement error requirement, the concentration Measurement accuracy model of data fusion instrument output pure gas sensor;

The pure gas concentration Measurement accuracy model that the ion flow valuve input step (6) of output obtains during (7) with carbon nano-tube film three electrode pure gas sensors, temperature sensor and humidity sensor actual measurement, the Measurement accuracy value of this model output pure gas concentration.

3. the method that detects pure gas concentration based on carbon nano-tube film three electrode sensors according to claim 2, it is characterized in that: in described carbon nano-tube film three electrode sensors, the second electrode potential is higher than the first electrode potential, and the third electrode current potential is lower than the second electrode potential and is higher than the first electrode potential.

4. the method that detects pure gas concentration based on carbon nano-tube film three electrode sensors according to claim 2, it is characterized in that: the described pure gas concentration measurement data storehouse of setting up, that experimental calibration data and interpolated data are formed database, with each sensor output ion flow valuve and interpolated data thereof as the input sample, with pure gas concentration, temperature and humidity calibration value and interpolated data thereof as the desired output sample.

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