A double quantum dot blending composite film environment sensor and a preparation method thereof

Abstract

The application discloses a kind of double quantum dot blending composite film environmental sensor and preparation method, a kind of double quantum dot blending composite film environmental sensor includes two groups of parallel interval arrangement substrate layer, two groups of the substrate layer between configuration has S type gas guide groove, the substrate layer is close to the side of S type gas guide groove interval and is equipped with several surface electrodes, the substrate layer between several surface electrodes is equipped with double quantum dot composite film, the beneficial effects of the present application are that the present environmental sensor uses amphoteric ion coordination group to improve the stability of inorganic perovskite quantum dot synthesis, to promote inorganic perovskite quantum dot and IV-VI group quantum dot blending structure growth, it is fast, high sensitivity, can simultaneously measure multiple gas and humidity parameters, response time is less than 20s, wide range of application, it can obtain required environmental sensor using one-step film preparation technology, preparation method is simple, fast and efficient, low in cost, suitable for large-scale production.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of thin film material preparation and sensor technology, and in particular to a double quantum dot blending composite film environmental sensor and a preparation method. BACKGROUND

[0002] In the prior art, semiconductor type gas / humidity environmental sensors have many advantages such as a large environmental adaptation range, anti-interference, high precision, small size, light weight, and low power consumption. The market demand for environmental sensors covers various aspects such as industry, environmental protection, agriculture, disease monitoring, home life, safety detection, and chemical analysis. Various devices based on traditional semiconductor material manufacturing technology are increasingly difficult to meet the requirements of today's social development, so the development of new materials has become the most fundamental solution. Quantum dot thin films provide a relatively inexpensive solution for the preparation of semiconductor devices due to their liquid phase process (such as spin coating, drop coating, pull-up coating, and spray printing, etc.). These properties can make quantum dot thin films an ideal material for the preparation of large-area devices and flexible devices. Therefore, the development of new nanostructures based on new quantum dots can provide new choices for the development of environmental devices.

[0003] Traditional group IV-VI materials (SnO2, SnS, PbS, etc.) as gas sensors have been successfully applied in industrial production due to their high stability and good system compatibility, but they also have disadvantages such as low response rate (>100s), high working temperature (100-300℃), and narrow detection range (only responding to specific gases). IV-VI quantum dot materials can effectively reduce the working temperature and improve the response rate due to their high film-forming property, large specific surface area, and high surface energy. Unlike IV-VI quantum dots, inorganic perovskite quantum dots have a high tolerance to material defects and surface states. The surface state, carrier concentration, and conductivity type of the material are extremely sensitive to temperature, humidity, atmosphere, and even light in the environment. Inorganic perovskite quantum dots can be obtained at low temperature and in an atmospheric environment using industrial-grade reagents. Despite the high concentration of point defects in the perovskite film, it still maintains a high quantum yield, which naturally fits the preparation of environmental sensors. However, inorganic perovskite quantum dots are highly dynamic adsorption of ligands and surface ions of nanocrystals, which can easily cause the desorption of surface ligands, leading to the agglomeration of perovskite nanocrystals, the decrease of film stability and film quality, and the reduction of photoelectric performance, resulting in high device operating voltage, large energy loss, and slow switching speed. Therefore, it is still difficult and challenging to apply quantum dot thin films to the preparation of high-performance devices. Therefore, how to organically combine the advantages of the two types of quantum dots has become a new research direction.

[0004] At present, the research on quantum dot-based detection devices is focused on the stability of single quantum dot films. This method requires high quality and stability of quantum dot films, making it difficult to obtain good performance parameters.

[0005] A Chinese invention patent with application number 201911149230.3 discloses a modified colloidal quantum dot film surface acoustic wave gas sensor and its preparation method. The method includes the following steps: A, providing a surface acoustic wave delay line, coating a colloidal quantum dot solution on the delay area of the surface acoustic wave delay line to form a colloidal quantum dot film; B, irradiating the colloidal quantum dot film with an ion beam or plasma to obtain a modified colloidal quantum dot film surface acoustic wave gas sensor. However, this kind of modified colloidal quantum dot film surface acoustic wave gas sensor only responds to specific environmental factors, has narrow selectivity, leads to small application range and high working temperature, it cannot measure multiple gases and humidity parameters at the same time, and its preparation method is low in efficiency and not suitable for large-scale production. SUMMARY

[0006] The purpose of the present application is to provide a double quantum dot blending composite film environmental sensor and a preparation method.

[0007] To achieve the above-mentioned purpose, the technical solution provided by the present application is as follows:

[0008] A double quantum dot blending composite film environmental sensor, comprising two groups of parallel and spaced substrate layers, an S-shaped gas guide groove is arranged between the two groups of substrate layers, a plurality of surface electrodes are arranged on one side of the substrate layer close to the S-shaped gas guide groove, and a double quantum dot composite film is arranged on the substrate layer between the plurality of surface electrodes.

[0009] The substrate layer is any one of a doped silicon wafer with silicon oxide, a sodium calcium silicon glass, a quartz glass, an organic glass, and an organic flexible substrate.

[0010] The surface electrode is any one or a composite electrode composed of several of a tin dioxide electrode, an indium tin oxide electrode, a gold electrode, a silver electrode, an aluminum electrode, a titanium electrode, and a copper electrode.

[0011] The material of the gas guide groove is epoxy resin or various sealing rubbers.

[0012] A preparation method of a double quantum dot blending composite film environmental sensor, comprising the following steps:

[0013] 1) Take a substrate, cover the position of the reserved gas guide groove partition with high-temperature adhesive tape, and make surface electrodes separated from each other on the substrate layer at the groove position;

[0014] 2) Uniformly cover a double quantum dot blending solution on the surface with electrodes to obtain a composite structure film layer.

[0015] 3) Take ligand, add different polar solvents, get mixed solution, the ratio of ligand to solvent is 0.1-0.25 mol / L, add ligand solvent in the mixed solution, prepare ligand solution, the volume ratio of mixed solution to ligand solvent is 1:30-150;

[0016] 4) Take ligand solution, smear on the surface of the film, stand for 30-120 s, repeat 2-3 times, clean, heat treatment at 75-85℃ for 3-5 min;

[0017] 5) Tear off the high-temperature adhesive tape, place the separation material at the position of the reserved air guide groove partition to form an S-shaped air guide groove;

[0018] 6) Place the same structure film / substrate layer prepared by steps 1)-4) on the S-shaped air guide groove and seal to obtain an environmental sensor.

[0019] In step 1), the thickness of the surface electrode is 30-50 nm.

[0020] In step 2), the film covering method is to use the pulling method, take quantum dots, add toluene or normal temperature liquid n-alkane to prepare a 50-200 mg / ml solution, place the substrate in the solution and pull up at a speed of 20-200 mm / min.

[0021] In steps 3) and 4), necessary cleaning and ligand exchange steps must be taken when preparing the film after the two materials are compounded;

[0022] The ligand is any one or several of benzene alkyl ammonium halide, hexadecyl to docosyl trimethyl ammonium halide, and tetra-n-butyl ammonium halide;

[0023] The ligand solvent is any one or several of methanol, ethanol, dimethylformamide, and acetonitrile;

[0024] The ligand solution is prepared by the pulling method, and the pulling speed is 20-200 mm / min.

[0025] The preparation process of the double quantum dot blending solution is as follows:

[0026] S1: Use a hot injection method to synthesize monodisperse inorganic perovskite quantum dots of different compositions, use cesium oleate to obtain a cesium precursor, use an amphoteric ion coordination ligand as a stabilizer, use octadecene as a solvent to dissolve lead halide as a lead halide precursor, and inject the cesium precursor to synthesize inorganic perovskite quantum dots;

[0027] S2: Group IV-VI quantum dots are added to the above solution, a certain amount of the above solution is injected into methylbenzene under high-speed stirring, and the growth of the double quantum dot blending material is carried out at a certain temperature, and then the temperature is rapidly reduced to stop the reaction;

[0028] S3: Add acetone to the solution in S2 and centrifuge at a high speed of 1500 r / min for 10-15 min, and then discard the supernatant, and then add a certain amount of methylbenzene for sufficient dissolution, and the step is repeated 2-3 times to obtain a double quantum dot blending solution.

[0029] In S1, an amphoteric ion coordination group is added as a stabilizer during the synthesis of inorganic perovskite quantum dots;

[0030] The surface ligand as the stabilizer is sulfobetaine or choline phosphate or gamma-amino acid.

[0031] In S2, the group IV-VI quantum dots are inorganic compound quantum dot materials formed by the fourth main group elements Ge, Sn, Pb and the sixth main group elements O, S, As and Te;

[0032] The group IV-VI quantum dots are PbS, SnS and SnO2 quantum dots;

[0033] In S2, the temperature is 75-85 DEG C to ensure that the blending structure is fully grown.

[0034] During the preparation of the double quantum dot composite film, the group IV-VI quantum dots and the inorganic perovskite quantum dots grow and combine to form double quantum dot blending composite materials with different densities and structures, and the group IV-VI quantum dot material is added for compounding before the inorganic perovskite quantum dots are synthesized and washed.

[0035] The beneficial effects of the present application are:

[0036] The environmental sensor utilizes the amphoteric ion coordination group to improve the stability of the inorganic perovskite quantum dot synthesis, so as to promote the growth of the inorganic perovskite quantum dot and the group IV-VI quantum dot blending structure, has fast response speed and high sensitivity, can simultaneously measure multiple gases and humidity parameters, has a response time of less than 20 s, has wide application range, and can obtain the required environmental sensor by using one-step film preparation technology, has simple preparation method, fast and efficient, low cost, and is suitable for large-scale production. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 is a schematic diagram of the three-dimensional structure of the environmental sensor of the present application;

[0038] Figure 2 is a schematic diagram of the substrate layer and the S-shaped gas guide groove of the present application;

[0039] Figure 3It is an electron microscope image of the double quantum dot film in the channel of the environmental sensor of the present application;

[0040] Figure 4 It is a humidity response graph of the environmental sensor of the present application in a standard cycle;

[0041] Figure 5 It is a hydrogen sulfide gas response graph of the environmental sensor of the present application in a standard cycle.

[0042] In the figure: 1, substrate layer; 2, S-shaped gas guide groove; 3, surface electrode; 4, double quantum dot composite film. DETAILED DESCRIPTION

[0043] The present application will be further described in detail below with reference to the accompanying drawings,

[0044] A double quantum dot blending composite film environmental sensor, comprising two groups of parallel and spaced substrate layers 1, an S-shaped gas guide groove 2 is arranged between the two groups of substrate layers 1, a plurality of surface electrodes 3 are arranged on one side of the substrate layer 1 close to the S-shaped gas guide groove 2, and a double quantum dot composite film 4 is arranged on the substrate layer 1 between the plurality of surface electrodes 3, and a three-dimensional structural schematic diagram of the environmental sensor of the present application is shown in Figure 1 .

[0045] The substrate layer 1 is any one of a doped silicon wafer with silicon oxide, soda-lime-silica glass, quartz glass, organic glass, and an organic flexible substrate;

[0046] The surface electrode 3 is any one or a composite electrode composed of several of a tin dioxide electrode, an indium tin oxide electrode, a gold electrode, a silver electrode, an aluminum electrode, a titanium electrode, and a copper electrode;

[0047] The material of the gas guide groove is epoxy resin or various sealing rubbers, and the gas guide groove is composed of groove partitions, and a cooperation schematic diagram of the substrate layer 1 and the S-shaped gas guide groove 2 of the present application is shown in Figure 2 .

[0048] A preparation method of a double quantum dot blending composite film environmental sensor, comprising the following steps:

[0049] 1) Take a substrate, cover the position where the gas guide groove partition is reserved with high-temperature adhesive tape, and make surface electrodes 3 separated from each other on the substrate layer 1 at the groove position;

[0050] 2) Uniformly cover the double quantum dot blending solution on the surface with the electrodes engraved, to obtain a composite structure film layer;

[0051] 3) Take ligand, add different polar solvents, get mixed solution, the ratio of ligand to solvent is 0.1-0.25 mol / L, add ligand solvent in the mixed solution, prepare ligand solution, the volume ratio of mixed solution to ligand solvent is 1:30-150;

[0052] 4) Take ligand solution, smear on the surface of the film, stand for 30-120 s, repeat 2-3 times, wash, heat treatment at 75-85℃ for 3-5 min;

[0053] 5) Tear off the high-temperature adhesive tape, place the separation material at the position of the reserved air guide groove partition to form an S-shaped air guide groove 2;

[0054] 6) Place the same structure film / substrate layer 1 prepared by steps 1)-4) on the S-shaped air guide groove 2 and seal to obtain an environmental sensor.

[0055] In step 1), the thickness of the surface electrode 3 is 30-50 nm.

[0056] In step 2), the film covering method is to take quantum dots, add toluene or normal temperature liquid n-alkane to prepare a 50-200 mg / ml solution, place the substrate in the solution and pull up, the pulling speed is 20-200 mm / min.

[0057] In steps 3) and 4), necessary washing and ligand exchange steps must be taken after the two materials are compounded to prepare the film;

[0058] The ligand is any one or several of benzene alkyl ammonium halide, hexadecyl to docosyl trimethyl ammonium halide, and tetra-n-butyl ammonium halide;

[0059] The ligand solvent is any one or several of methanol, ethanol, dimethylformamide, and acetonitrile;

[0060] The ligand solution is prepared by the pulling method, and the pulling speed is 20-200 mm / min.

[0061] The preparation process of the double quantum dot blended solution is as follows:

[0062] S1: Single dispersed inorganic perovskite quantum dots of different compositions are synthesized by a hot injection method, cesium oleate is used to obtain a cesium precursor, an amphoteric ion coordination ligand is used as a stabilizer, octadecene is used as a solvent to dissolve lead halide as a lead halide precursor, and the inorganic perovskite quantum dots are synthesized by injecting the cesium precursor;

[0063] S2: Group IV-VI quantum dots are added to the above solution, a certain amount of the above solution is injected into methylbenzene under high-speed stirring to grow double quantum dot blended materials at a certain temperature, and then the temperature is rapidly reduced to stop the reaction;

[0064] S3: add acetone to the solution in S2 and discard the supernatant after centrifugation at high speed of 1500r / min for 10-15min, then add a certain amount of toluene for sufficient dissolution, repeat this step 2-3 times to obtain a double quantum dot blended solution.

[0065] In S1, an amphoteric ion coordination group is added as a stabilizer during the synthesis of inorganic perovskite quantum dots;

[0066] Preferably, the surface ligand as a stabilizer is sulfobetaine or choline phosphate or γ-amino acid.

[0067] In S2, the group IV-VI quantum dots are inorganic compound quantum dot materials formed by the fourth main group elements Ge, Sn, Pb and the sixth main group elements O, S, As, Te;

[0068] Preferably, the group IV-VI quantum dots are PbS, SnS, SnO2 quantum dots;

[0069] The temperature in S2 is 75-85°C to ensure that the blended structure grows fully.

[0070] During the preparation of the double quantum dot composite film 4, the group IV-VI quantum dots and the inorganic perovskite quantum dots grow and combine to form double quantum dot blended composite materials with different densities and structures. The group IV-VI quantum dot material is added for compounding after the synthesis of the inorganic perovskite quantum dots and before washing.

[0071] Example 1:

[0072] A preparation method of a double quantum dot blended composite film environmental sensor, comprising the following steps:

[0073] 1) Single dispersed inorganic perovskite quantum dots with different compositions are synthesized by a hot injection method, an amphoteric ion coordination group is used as a stabilizer, octadecene is used as a solvent, and lead halide is used as a lead halide precursor to dissolve;

[0074] 2) Then inject cesium precursor to synthesize inorganic perovskite quantum dots, and the molar ratio of lead halide precursor to cesium precursor is 2:1;

[0075] 3) Add group IV-VI quantum dots to the above solution, take a certain amount of the above solution and inject it into toluene under high-speed stirring at a certain temperature to grow double quantum dot blended materials, then quickly reduce the temperature to stop the reaction, the mass ratio of group IV-VI quantum dots to the solution is 1:150-1500, take a certain amount of the above solution and inject it into toluene under high-speed stirring at 1500r / min, control the temperature at 75-85°C until the toluene solution changes color, then reduce the temperature to stop the reaction;

[0076] 4) Add acetone to the solution in 3) and discard the supernatant after centrifugation at a high speed of 1500 r / min for 10-15 min, then add a certain amount of toluene for sufficient dissolution, and repeat this step 2-3 times to obtain a concentrated double quantum dot blended material solution;

[0077] 5) Take the substrate, cover the reserved air channel partition position with high-temperature adhesive tape, and make surface electrodes 3 on the substrate layer 1 at the channel position, which are separated from each other, and the electrode thickness is 30-50 nm;

[0078] 6) Add toluene or normal-temperature liquid n-alkane to the double quantum dot blended solution to prepare a 50-200 mg / ml solution, and pull the film on the substrate in the solution at a pulling speed of 20-200 mm / min;

[0079] 7) Take the ligand, add different polar solvents to obtain a mixed solution, the ratio of the ligand to the solvent is 0.1-0.25 mol / L, add the ligand solvent to the mixed solution to prepare a ligand solution, and the volume ratio of the mixed solution to the ligand solvent is 1:30-150;

[0080] 8) Soak the film in 6) in the ligand solution for 30-120 s, then pull it at a speed of 20-200 mm / min, repeat 2-3 times, clean, and heat treat at 75-85°C for 3-5 min;

[0081] 9) Tear off the high-temperature adhesive tape, place the separation material at the reserved air channel partition position to form an S-shaped air channel 2.

[0082] 10) Place the same structure film / substrate layer 1 prepared by steps 5)-8) on the S-shaped air channel 2 and seal to obtain an environmental sensor.

[0083] Example Two:

[0084] A preparation method of a double quantum dot blended composite film environmental sensor, comprising the following steps:

[0085] 1) Take 0.25 g of γ-amino acid, 0.5 ml of oleic acid, 0.15 mmol of lead halide, and 5 ml of octadecene, mix them into a three-necked flask, vacuumize, heat and dissolve to obtain a lead halide precursor;

[0086] 2) Take 0.325 g of cesium carbonate, 1.5 ml of oleic acid, and 50 ml of isopropyl glycol dibutyl ether to prepare a cesium precursor, then take 2 ml of the cesium precursor and inject it into the lead halide precursor to synthesize inorganic perovskite quantum dots;

[0087] 3) Take 0.04 mg PbS quantum dots to add to the above solution to grow in-situ composite structure, take a certain amount of the above solution to inject into 80℃ methylbenzene with high speed stirring at 1500 r / min, until the methylbenzene solution changes color, then stop the reaction after cooling;

[0088] 4) Add acetone to the solution in 2) and centrifuge at high speed of 1500 r / min for 10-15 min, then discard the supernatant, then add a certain amount of methylbenzene to dissolve thoroughly, repeat this step 2-3 times to obtain a solution of double quantum dot material;

[0089] 5) Take organic glass substrate as substrate layer 1, cover the reserved gas channel partition position with high temperature adhesive tape, then put the substrate covered with electrode mask in the groove into the vacuum coating system to evaporate gold electrode, and the thickness of the evaporated electrode is 40 nm;

[0090] 6) Take the methylbenzene solution of double quantum dot material, configure the concentration to be 50 mg / mL, and put the substrate into the solution to perform pull-up film coating, the pull-up speed is 20 mm / min, and a thin film layer is obtained;

[0091] 7) Take 0.5 g of benzene alkyl ammonium bromide as a ligand, add 20 mL of methanol to obtain a mixed solution as a ligand solvent, uniformly stir, and prepare a clear ligand solution;

[0092] 8) Put the quantum dot thin film into the ligand solution for ligand exchange for 10 s, then pull up the thin film with a pull-up speed of 100 mm / min, and repeat 2 times;

[0093] 9) Drop methanol on the surface of the thin film obtained in step 8) to uniformly cover it, stand for 2 min, repeat this step 3 times, and heat treat at 80℃ for 5 min to obtain an environmental sensor.

[0094] Wherein, the environmental sensor obtained in the embodiment is placed under an electron microscope for magnification, and the electron microscope image of the double quantum dot thin film in the channel of the environmental sensor of the application is as shown in Figure 3 The Figure 3 It can be seen that the thin film material in the channel of the environmental sensor obtained by the application is uniform, dense and crack-free.

[0095] Wherein, the environmental sensor obtained in the embodiment is placed in a calibrated humidity to determine its response to humidity, and the humidity response graph of the environmental sensor of the application in a standard cycle is as shown in Figure 4 The Figure 4 It can be seen that the response time of the environmental sensor is less than 5 s.

[0096] The environmental sensor obtained in the embodiment is placed in 0.5ppm H2S gas to determine its response to hydrogen sulfide gas, and a standard cycle of hydrogen sulfide gas response graph of the environmental sensor of the application is shown in Fig. 1. Figure 5 As shown in Fig. 1. Figure 5 It can be seen that the response time of the environmental sensor is less than 15s.

[0097] In the embodiment, the detection capability of the environmental sensor obtained in the application to humidity and different gases is shown in Table 1.

[0098] Environmental factor Detection range (ppm) Response time τr / τf (s) Humidity Relative humidity 4.8 / 5.0 NH3 10-200 8.5 / 12 H2S 0.1-50 9 / 12.5 NO2 0.5-400 7.8 / 13.5

[0099] As shown in Table 1, the environmental sensor can simultaneously have sensitive detection capability to humidity and different gases.

[0100] Working principle:

[0101] First, the stability of the synthesis of inorganic perovskite quantum dots is improved by using amphoteric ion coordination groups to promote the growth of inorganic perovskite quantum dots and IV-VI quantum dots in a blended structure; then the required electrodes are made on the substrate layer 1, covering the double quantum dot film, adding different surfactants as ligands for ligand exchange on the film, then adding a gas guide groove and further packaging the double quantum dot structure film, thereby completing the preparation of the environmental sensor, that is, the environmental sensor has a double quantum dot composite film 4 on the substrate layer 1 between the surface electrodes 3, the surface of the quantum dot film is modified by inorganic ligands, an s-shaped gas guide groove is provided on the substrate layer 1, and finally a film / substrate layer 1 with the same structure is packaged on it, thereby completing the preparation of the environmental sensor; the inorganic perovskite quantum dots are blended and grown with IV-VI quantum dot materials during synthesis, which can make the interface have better bonding, improve film formation, promote the separation of photo-generated carriers and produce more effective carrier transport, thereby obtaining better environmental factor selectivity, wider working range and better performance. By blending and growing double quantum dots, the required environmental sensor can be obtained by only one step of film preparation technology, which greatly simplifies the device preparation operation steps and effectively reduces the cost. The blending and growing method effectively improves the performance of the device, and the gas guide groove and multiple electrodes can be used to simultaneously detect multiple gases and humidity. The prepared environmental sensor has fast response speed, high sensitivity, response time less than 20s, and wide application range, and can simultaneously detect humidity, ammonia, nitrogen oxides, sulfur oxides, hydrogen sulfide and other gases.

[0102] The application has the beneficial effect that the environment sensor utilizes the amphoteric ion coordination group to improve the stability of inorganic perovskite quantum dot synthesis, so as to promote the growth of inorganic perovskite quantum dot and IV-VI group quantum dot blending structure, has fast response speed, high sensitivity, can simultaneously measure multiple gas and humidity parameters, has a response time of less than 20s, has wide application range, and can obtain the required environment sensor by using one-step film preparation technology, has simple preparation method, fast and efficient, low cost, and is suitable for large-scale production.

[0103] The above describes one embodiment of the application in detail, but the content is only the preferred embodiment of the application and cannot be considered as limiting the scope of the application. Any equivalent changes and improvements made according to the scope of the application should still belong to the patent scope of the application.

Claims

1. A bi-quantum dot blended composite thin film environmental sensor, characterized in that, The application relates to an environmental sensor, which comprises two groups of parallelly arranged substrate layers (1), S-shaped air guide grooves (2) are arranged between the two groups of substrate layers (1), a plurality of surface electrodes (3) are arranged on one side of the substrate layers (1) close to the S-shaped air guide grooves (2), and double-quantum-dot composite films (4) are arranged on the substrate layers (1) between the surface electrodes (3). The substrate layer (1) is any one of a doped silicon wafer with silicon oxide, soda-lime-silica glass, quartz glass, organic glass and an organic flexible substrate. The surface electrode (3) is any one or a composite electrode composed of several of tin dioxide electrodes, indium tin oxide electrodes, gold electrodes, silver electrodes, aluminum electrodes, titanium electrodes and copper electrodes. The material of the air guide groove is epoxy resin or various sealing rubbers. The preparation method of the double-quantum-dot blending composite film environmental sensor comprises the following steps: 1) taking a substrate, covering the positions of the air guide groove partitions with high-temperature adhesive tape, and manufacturing surface electrodes (3) separated from each other on the substrate layer (1) at the groove positions; 2) uniformly covering a double-quantum-dot blending solution on the surface with the electrodes, and obtaining a composite structure film layer; 3) taking a ligand, adding different polar solvents to obtain a mixed solution, the ratio of the ligand to the solvent being 0.1-0.25 mol / L, adding a ligand solvent in the mixed solution to prepare a ligand solution, and the volume ratio of the mixed solution to the ligand solvent being 1:30-150; 4) taking the ligand solution, smearing the surface of the film, standing for 30-120 s, repeating 2-3 times, cleaning, and heat treating at 75-85 DEG C for 3-5 min; 5) tearing off the high-temperature adhesive tape, placing a separation material at the positions of the air guide groove partitions to form S-shaped air guide grooves (2); 6) placing a substrate layer with the same structure prepared by steps 1)-4) on the S-shaped air guide grooves (2) and sealing to obtain an environmental sensor; The preparation process of the double-quantum-dot blending solution is as follows: S1: using a hot injection method to synthesize monodispersed inorganic perovskite quantum dots with different components, using cesium oleate to obtain a cesium precursor, using an amphoteric ion coordination ligand as a stabilizer, using octadecene as a solvent to dissolve lead halide as a lead halide precursor, and injecting the cesium precursor to synthesize the inorganic perovskite quantum dots; S2: adding group IV-VI quantum dots into the above solution, taking a certain amount of the above solution, injecting the solution into methylbenzene under high-speed stirring, and growing double-quantum-dot blending materials under a certain temperature, and then rapidly reducing the temperature to stop the reaction; S3: adding acetone into the solution in S2 and centrifuging at 1500 r / min for 10-15 min to discard the supernatant, and then adding a certain amount of methylbenzene to fully dissolve, and the step is repeated 2-3 times to obtain the double-quantum-dot blending solution.

2. A bi-quantum dot blended composite thin film environmental sensor as claimed in claim 1, wherein, In step 1), the thickness of the surface electrode (3) is 30-50 nm.

3. A bi-quantum dot blended composite thin film environmental sensor as claimed in claim 2, wherein, In step 2), the film covering method is a pulling method, quantum dots are taken, methylbenzene or normal-temperature liquid n-alkane is added to prepare a 50-200 mg / ml solution, the substrate is placed in the solution and pulled upwards, and the pulling speed is 20-200 mm / min.

4. A bi-quantum dot blended composite thin film environmental sensor as claimed in claim 3, wherein, In steps 3) and 4), the thin film must be washed and ligand-exchanged after the two materials are compounded; The ligand is any one or several of benzene alkyl ammonium halide, cetyl to docosyl trimethyl ammonium halide, and tetra-n-butyl ammonium halide; The ligand solvent is any one or several of methanol, ethanol, dimethylformamide, and acetonitrile; The method of applying the ligand solution to prepare the double quantum dot thin film is the pulling method, and the pulling speed is 20-200 mm / min.

5. A bi-quantum dot blended composite thin film environmental sensor as claimed in claim 4, wherein, In S1, an amphoteric ion ligand is added as a stabilizer when the inorganic perovskite quantum dot is synthesized. The surface ligand as the stabilizer is sulfobetaine or choline phosphate or γ-amino acid.

6. A bi-quantum dot blended composite thin film environmental sensor as claimed in claim 5, wherein, In S2, the group IV-VI quantum dot is an inorganic compound quantum dot material formed by any one of the fourth main group elements Ge, Sn, and Pb and any one of the sixth main group elements O, S, As, and Te. In S2, the temperature is 75-85℃ to ensure that the blended structure grows fully.

7. A bi-quantum dot blended composite thin film environmental sensor as claimed in claim 6, wherein, In the preparation process of the double quantum dot composite thin film (4), the group IV-VI quantum dot and the inorganic perovskite quantum dot grow and combine to form a double quantum dot blended composite material with different densities and structures. The group IV-VI quantum dot material is added to compound after the inorganic perovskite quantum dot is synthesized and before it is washed.

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