A multifunctional device and its fabrication method

Abstract

The present invention provides a multifunctional device, including a substrate, a thin film electrode, quantum dot colloidal particles, and a metal electrode. The present invention obtains a multifunctional device by disconnecting a strip-shaped two-dimensional material film on a substrate, and reconnecting the disconnected film with colloidal quantum dots under the action of an external driving voltage, and finally forms a special planar structure of two-dimensional material film / quantum dots / two-dimensional material film. The multifunctional device provided by the present invention has functions similar to traditional photodiodes, and has good rectification characteristics and photoelectric detection performance. The difference between the multifunctional device provided by the present invention and traditional semiconductor photodiodes is that its performance is less affected by temperature and has a very high photoelectric response. At the same time, the preparation method of the multifunctional device provided by the present invention is simple in process, has no selection of substrates, and has a wide range of raw materials for two-dimensional material films and quantum dots, is easy to prepare, has low cost, is environmentally friendly, and is suitable for industrial production.

Description

Technical Field

[0001] The present invention relates to the field of photoelectric detection technology, and in particular to a multifunctional device and a preparation method thereof. Background Art

[0002] Basic electronic devices such as diodes and photodetectors are common and indispensable electronic devices in people's lives. Electronic devices based on traditional semiconductors can no longer meet people's growing needs, and low-dimensional materials and devices are becoming the cutting-edge field in today's scientific community. Among them, low-dimensional materials such as graphene, monolayer molybdenum disulfide, few-layer black phosphorus, fullerene, carbon nanotubes, carbon quantum dots (CQDs) have been widely studied due to their excellent physical properties and chemical stability. Many composite structures are realized by physical stacking methods and have been widely studied and made into prototype electronic devices. For example, Grzybowski et al. (Nature nanotechnology, 2016, 11 (7): 603-608.) used functionalized metal nanoparticles with charged organic ligands to manufacture chemical electronic circuits. By adhering two layers of different charged metal nanoparticles, a diode without a semiconductor was created with an on / off ratio of 6. Chen et al. (Nano Letters, 2017, 17(7): 4122-4129.) doped the upper surface of half of black phosphorus with potassium ions, making that half doped with P-type and the other half intrinsically N-type, achieving an ideal factor of 1.007 and an on / off ratio of 10 4 pn homojunction diode.

[0003] However, the prior art electronic devices with multifunctional excellent structures have complicated preparation processes, complex raw material components, and unsatisfactory performance. There is a wide demand for photodetectors with high on / off ratio and high photoelectric response signal. Summary of the invention

[0004] In view of this, an object of the present invention is to provide a multifunctional device, wherein the multifunctional device provided by the present invention has a higher switching ratio and photoelectric response signal.

[0005] The present invention provides a multifunctional device, comprising:

[0006] substrate;

[0007] A first thin film electrode disposed on the surface of the substrate;

[0008] A second thin film electrode disposed on the surface of the substrate;

[0009] The first thin film electrode and the second thin film electrode are connected via quantum dot colloidal particles;

[0010] A portion of the first metal electrode is disposed on the surface of the first thin film electrode, and another portion of the first metal electrode is disposed on the surface of the substrate;

[0011] A portion of the second metal electrode is disposed on the surface of the second thin film electrode, and another portion of the second metal electrode is disposed on the surface of the substrate.

[0012] The present invention has no special restrictions on the type and source of the substrate, and a substrate familiar to those skilled in the art may be used, such as a silicon substrate, a glass substrate or a plastic substrate. The silicon substrate may be made of silicon or silicon dioxide; the glass substrate may be made of quartz glass; the plastic substrate is preferably a flexible organic plastic substrate; the plastic substrate may be made of polyimide, polyethylene naphthalate or polyethylene terephthalate.

[0013] In the present invention, the first thin film electrode and the second thin film electrode are both arranged on the surface of the substrate. The present invention has no special restrictions on the shape and size of the first thin film electrode and the second thin film electrode. Those skilled in the art can select the first thin film electrode and the second thin film electrode of suitable shape and size according to actual needs. In the present invention, the shape of the first thin film electrode and the second thin film electrode is preferably rectangular, the first thin film electrode and the second thin film electrode are arranged on the surface of the substrate at intervals, and the first thin film electrode and the second thin film electrode are preferably symmetrically distributed on the surface of the substrate. In the present invention, the shortest distance between the first thin film electrode and the second thin film electrode is preferably 5 to 30 microns, more preferably 10 to 25 microns, and most preferably 15 to 20 microns.

[0014] Since its discovery, two-dimensional materials have been one of the cutting-edge materials in scientific research. Taking graphene as an example, graphene has many unique properties, such as ultra-high carrier mobility, extremely low carrier concentration, large Young's modulus, good transmittance, large specific surface area, and easy assembly with other chemical groups. Since the advent of the method of growing single-layer graphene by chemical vapor deposition, the research on graphene has become more extensive, which has also enabled graphene to be closer to applications. In the present invention, the first thin film electrode and the second thin film electrode are preferably strip-shaped two-dimensional material thin film electrodes; the present invention has no special restrictions on the type of the two-dimensional material, and those skilled in the art can select different two-dimensional materials according to the performance of the required multifunctional device. The two-dimensional material thin film electrode is preferably a thin film electrode with a single-layer structure; the two-dimensional material is preferably graphene or a single-layer molybdenum disulfide.

[0015] Quantum dot colloidal particles are a very good fluorescent material, and are environmentally friendly and easy to prepare. In the present invention, the first thin film electrode and the second thin film electrode are separated by quantum dot colloidal particles, or in other words, connected by quantum dot colloidal particles. In the present invention, the quantum dot colloidal particles are preferably charged quantum dot colloidal particles. The present invention has no special restrictions on the type of the quantum dot colloidal particles, and those skilled in the art can select different quantum dot colloidal particles according to the performance of the desired multifunctional device; the quantum dot colloidal particles are preferably carbon quantum dot colloidal particles or gold quantum dot colloidal particles.

[0016] The multifunctional device provided by the present invention has a unique structure, and a two-dimensional material film is assembled with another quantum dot material to obtain a new multifunctional device with excellent performance.

[0017] In the present invention, part of the first metal electrode is arranged on the surface of the first thin film electrode, and the other part is arranged on the surface of the substrate, and the first thin film electrode is located between the substrate and the first metal electrode; part of the second metal electrode is arranged on the surface of the second thin film electrode, and the other part is arranged on the surface of the substrate, and the second thin film electrode is located between the substrate and the second metal electrode; the first metal electrode, the first thin film electrode and the substrate are all in contact; the second metal electrode, the second thin film electrode and the substrate are all in contact; part of the bottom surface of the first thin film electrode is in contact with the substrate, part of the surface of the first thin film electrode is in contact with part of the bottom surface of the first metal electrode, and another part of the bottom surface of the first metal electrode is in contact with the substrate; part of the bottom surface of the second thin film electrode is in contact with the substrate, part of the surface of the second thin film electrode is in contact with part of the bottom surface of the second metal electrode, and another part of the bottom surface of the second metal electrode is in contact with the substrate. The present invention has no special restrictions on the size and shape of the first metal electrode and the second metal electrode. Those skilled in the art can select the first metal electrode and the second metal electrode of appropriate shape and size according to actual needs. The first metal electrode and the second metal electrode are preferably rectangular. The first metal electrode is preferably arranged at the edge of the surface of the first thin film electrode, and the portion of the first metal electrode exceeding the surface of the first thin film electrode is in contact with the surface of the substrate; the second metal electrode is preferably arranged at the edge of the surface of the second thin film electrode, and the portion of the second metal electrode exceeding the surface of the second thin film electrode is in contact with the surface of the substrate.

[0018] In the present invention, the thickness of the first metal electrode and the second metal electrode is preferably 80 to 120 nm, more preferably 90 to 110 nm, and most preferably 100 nm.

[0019] The present invention has no special limitation on the materials of the first metal electrode and the second metal electrode, and metal electrodes well known to those skilled in the art may be used, such as a gold electrode, a silver electrode or a copper electrode.

[0020] The structural schematic diagram of the multifunctional device provided by the embodiment of the present invention is as follows Figure 1 As shown, Figure 1 (a) is a side view, (b) is a top view, including:

[0021] Substrate (1);

[0022] Two two-dimensional material thin film electrodes (3) are chemically vapor deposited on the left and right sides of the surface of the substrate (1);

[0023] A portion of the metal electrode (2) is arranged on the surface of two two-dimensional material thin film electrodes, and another portion of the metal electrode (2) is arranged on the surface of the substrate (1);

[0024] Quantum dot colloidal particles (4) are arranged between two two-dimensional material thin film electrodes.

[0025] In the present invention, a plurality of components including two two-dimensional thin film electrodes (3), a metal electrode (2) and quantum dot colloidal particles (4) can be arranged on the substrate, and these components can be arranged in parallel, such as Figure 1 As shown in b.

[0026] The present invention provides a method for preparing the multifunctional device described in the above technical solution, comprising:

[0027] Prepare a first thin film electrode and a second thin film electrode which are not in contact with each other on the surface of the substrate;

[0028] Using an external electric field to connect the first thin film electrode to the second thin film electrode through the quantum dot colloidal particle solution;

[0029] Disposing a first metal electrode on the first film electrode and the surface of the substrate;

[0030] A second metal electrode is disposed on the second film electrode and the surface of the substrate.

[0031] In the present invention, the materials and structures of the substrate, the first thin film electrode, the second thin film electrode, the quantum dot colloidal particles, the first metal electrode and the second metal electrode are consistent with the materials and structures of the substrate, the first thin film electrode, the second thin film electrode, the quantum dot colloidal particles, the first metal electrode and the second metal electrode described in the above technical scheme, and are not repeated here.

[0032] The present invention has no special restrictions on the preparation method of the first thin film electrode and the second thin film electrode. They can be prepared by a two-dimensional material preparation method familiar to those skilled in the art, such as low-pressure chemical vapor deposition, mechanical exfoliation, and high-temperature pyrolysis of silicon carbide to prepare graphene, and then etching the graphene into the desired electrode shape; or a two-temperature zone chemical vapor deposition method can be used to prepare a molybdenum disulfide film.

[0033] The present invention preferably uses wet transfer to transfer the first thin film electrode and the second thin film electrode to the substrate surface.

[0034] In the present invention, the quantum dot colloidal particle solution is disposed between the first thin film electrode and the second thin film electrode, and an electric field is applied to the quantum dot colloidal particle solution to realize the assembly of quantum dot colloidal particles between adjacent strip-shaped two-dimensional material thin film electrodes (the first thin film electrode and the second thin film electrode). In the present invention, by applying an electric field to the quantum dot colloidal particle solution, the quantum dot colloidal particles present a concentration gradient between the first thin film electrode and the second thin film electrode. In the present invention, it is preferred to apply a constant current stable voltage between the first metal electrode and the second metal electrode, and remove the voltage after the solvent in the quantum dot colloidal particle solution is completely evaporated.

[0035] In the present invention, the externally applied electric field is preferably a constant current field, and the intensity of the externally applied electric field is preferably 1 to 3 V / cm, more preferably 1.5 to 2.5 V / cm, and most preferably 2 V / cm. In the present invention, the quantum dot colloidal particle solution is preferably an aqueous solution of quantum dot colloidal particles. The present invention has no special restrictions on the preparation method of the quantum dot colloidal particle solution, and the preparation technical scheme of the quantum dot colloidal particle solution well known to those skilled in the art can be adopted. In the present invention, the quantum dot colloidal particle solution is preferably a carbon quantum dot colloidal particle solution or a gold quantum dot colloidal particle solution; the preparation method of the carbon quantum dot colloidal particle solution is preferably:

[0036] Graphite rods were placed in deionized water as two electrodes;

[0037] A DC constant voltage power supply is applied to the two electrodes to electrolyze the graphite rod to obtain a solution;

[0038] The solution is centrifuged to obtain a precipitate;

[0039] The precipitate is dispersed in deionized water to obtain a carbon quantum dot colloidal particle solution.

[0040] In the present invention, the graphite rod is preferably a high-purity graphite rod; and the resistivity of the deionized water is preferably greater than 18.2 megohms / cm.

[0041] In the present invention, the preparation method of the gold quantum dot colloidal particle solution is preferably a hydrothermal method, such as using trisodium citrate as a reducing agent, heating in a water bath, adding chloroauric acid thereto and stirring vigorously to obtain a gold quantum dot colloidal particle solution.

[0042] The present invention applies the external electric field drive method to the preparation of multifunctional devices (photodetectors) for the first time, and proposes a new preparation method. The preparation method provided by the present invention is simple in process, low in cost, and has no selectivity for substrates. A mature Si-based substrate or a transparent flexible substrate can be selected, which expands the application range of the multifunctional devices provided by the present invention. In addition, the two-dimensional material film and quantum dot material used in the present invention are low-dimensional materials, and the raw materials are widely available, easy to prepare, environmentally friendly, and suitable for industrial production.

[0043] Compared with the prior art, the multifunctional device provided by the present invention is a device that assembles a two-dimensional material film and another quantum dot material in an ingenious structure to prepare a rectifying behavior device with a high switching ratio and a high-response photodetector. The present invention utilizes the excellent electrical properties of the two-dimensional material film, makes the two-dimensional material into electrodes, and cleverly assembles quantum dots between the two-dimensional material film electrodes by driving an external electric field. The multifunctional device provided by the present invention has the advantages of high switching ratio and high photoelectric response, and the preparation and assembly method of the multifunctional device provided by the present invention can be extended to the assembly of different two-dimensional materials and colloidal particles to obtain multifunctional devices with different performances, which has far-reaching significance.

[0044] Compared with traditional semiconductor diodes, the multifunctional device provided by the present invention is insensitive to temperature and has a good switching ratio, which is superior to the existing known quantum dot-based rectifier devices and is insensitive to the external gate voltage. The multifunctional device provided by the present invention has a good photoelectric response to visible light, and the photoelectric sensitivity exceeds that of commercial photoelectric detectors on the market. It has a strong response to light of different wavelengths, which is consistent with the absorption spectrum of the quantum dots themselves, and has very good stability and can work continuously and stably. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0046] Figure 1 A schematic diagram of the structure of a multifunctional device provided by an embodiment of the present invention;

[0047] Figure 2 The Raman spectra of graphene and carbon quantum dots in Example 1 of the present invention;

[0048] Figure 3 This is a schematic diagram of the device structure change during the preparation of the multifunctional device in Example 1 of the present invention;

[0049] Figure 4 The rectification curve of the multifunctional device provided in Example 1 of the present invention;

[0050] Figure 5 The actual optical microscope photos of the graphene electrode in Example 2 of the present invention (at different distances);

[0051] Figure 6 A physical diagram of a multifunctional device provided in Example 3 of the present invention;

[0052] Figure 7 The current-voltage curve of the multifunctional device provided in Example 4 of the present invention during the cooling process;

[0053] Figure 8 The photoelectric response curve of the multifunctional device provided in Example 5 of the present invention to 405nm incident light;

[0054] Fig. 9 This is the current-voltage curve of the multifunctional device provided in Example 6 of the present invention to an incident light of 532 nm. DETAILED DESCRIPTION

[0055] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] Example 1

[0057] The structural schematic diagram of the multifunctional device provided in Example 1 of the present invention is as follows Figure 1 As shown, it comprises: a silicon oxide substrate (1), two graphene thin film electrodes (3) arranged on the left and right sides of the silicon oxide substrate surface with a distance of 10 microns, and carbon quantum dots (4) are arranged between the two graphene thin film electrodes; and parts of gold electrodes (2) are respectively arranged on the surfaces of the two graphene thin film electrodes, and the other parts of the gold electrodes are in contact with the substrate.

[0058] The schematic diagram of the structural change of the multifunctional device during the preparation process of Example 1 of the present invention is as follows Figure 3 As shown, the method for preparing the multifunctional device is as follows:

[0059] 1) The preparation of single-layer graphene adopts the chemical vapor deposition method:

[0060] The copper foil was soaked in an acetic acid aqueous solution with a mass ratio of acetic acid to water of 1:1 for 4 hours, and then the residue on the surface of the copper foil was cleaned with acetone and isopropanol. The copper foil was cut into a size of 10cm*10cm and placed in a quartz tube. The quartz tube cavity was evacuated. When the vacuum requirement was met in the cavity, the temperature was raised to 1000℃, annealed in a hydrogen atmosphere, a small amount of methane was introduced, reacted for a period of time, and then quickly cooled to room temperature. After the temperature dropped to room temperature, the grown graphene was taken out for use.

[0061] 2) Preparation of carbon quantum dot solution:

[0062] High-purity graphite rods are used as two electrodes and placed in deionized water (resistivity greater than 18.2 megohms / cm). A DC constant voltage power supply is applied to the two electrodes. After a long time, the graphite rods electrolyze themselves to form a solution. The solution is centrifuged and the resulting precipitate is dispersed in deionized water again to obtain a carbon quantum dot solution.

[0063] 3) The transfer method of single-layer graphene is wet transfer:

[0064] The copper-based graphene prepared above was flattened, and a layer of polymethyl methacrylate (PMMA) was spin-coated on the upper surface for protection at a speed of 4000 rpm for 1 minute. It was then floated in a corrosive solution (ferric chloride solution) for 12 hours to etch the copper foil cleanly, and the obtained graphene film was transferred to the surface of a silicon oxide substrate.

[0065] 4) Use micro-nano processing methods to prepare electrodes from the transferred graphene. This is done in a clean room. Because it involves exposure, it is in the yellow light area:

[0066] First, a layer of photoresist (AZ6112) is spin-coated on the graphene surface, and a pattern is prepared on the graphene surface by ultraviolet lithography with an exposure time of 2s and a development time of 40s. Then, pre-baking is performed, and then plasma etching is performed with an oxygen flow rate of 50sccm, a power of 200W, and a time of 30s to etch the graphene into the required shape. Finally, the steps of coating, photolithography, and development are repeated to obtain a graphene thin film electrode.

[0067] The metal electrode was prepared by magnetron sputtering, with a titanium substrate of 10 nm and a gold coating of 100 nm. The metal-plated sample was placed in acetone for stripping to obtain a gold electrode.

[0068] 5) Preparation of multifunctional devices:

[0069] The prepared carbon quantum dot aqueous solution is dropped between two graphene electrodes, gold electrodes are covered on the surfaces of the two graphene electrodes, a constant current voltage of 2V / cm is applied across the two gold electrodes, and carbon quantum dot colloidal particles are assembled and arranged to obtain a multifunctional device.

[0070] The graphene and carbon quantum dot solution prepared in Example 1 of the present invention were subjected to Raman detection, and the detection results are as follows: Figure 2 As shown, according to Figure 2 The Raman spectrum of the carbon quantum dots shows that the characteristic peaks of carbon materials are well present.

[0071] The multifunctional device prepared in Example 1 of the present invention was tested using a Keithley 2410 ammeter. The test results are as follows: Figure 4 As shown, from Figure 4 It can be seen that the multifunctional device prepared in Example 1 of the present invention has a very good switching ratio, can tolerate a voltage of ±15V, and the reverse cutoff current is also very stable.

[0072] Example 2

[0073] According to the method of Example 1, a plurality of multifunctional devices with different graphene film electrode distances are prepared, and the distance between two graphene film electrodes is between 5 and 30 microns. Figure 5 shown.

[0074] Example 3

[0075] Two multifunctional devices were prepared according to the method described in Example 1. The difference from Example 1 is that different substrates were used. The substrate of one multifunctional device was polyethylene naphthalate (PEN). Figure 6 As shown in a), another multifunctional device has a substrate of polydimethylsiloxane (PDMS), such as Figure 6 As shown in b).

[0076] Example 4

[0077] A multifunctional device was prepared according to the method described in Example 1, which differs from Example 1 in that graphene was prepared by high-temperature pyrolysis of silicon carbide:

[0078] The silicon carbide whose surface has been oxidized or hydrogen-etched is heated to 1000°C by electron bombardment under ultra-high vacuum conditions to remove the oxide on its surface. The silicon carbide sample with the oxide removed is heated to 1450°C and kept at a constant temperature for 15 minutes to obtain graphene.

[0079] The voltage and current of the multifunctional device prepared in Example 4 of the present invention during the cooling process were tested using a comprehensive physical property measurement platform (PPMS). The test results are as follows: Figure 7 As shown, from Figure 7 It can be seen that the temperature has little effect on the multifunctional device prepared in the embodiment of the present invention.

[0080] Example 5

[0081] A multifunctional device was prepared according to the method described in Example 1. The difference from Example 1 is that gold particles were used instead of the carbon quantum dots in Example 1. The preparation method of the gold particles was a hydrothermal method:

[0082] Use trisodium citrate as a reducing agent, heat in a water bath, slowly drop chloroauric acid into the solution, stir vigorously, and after about 2 hours, a deep pink gold particle solution is obtained.

[0083] A high-frequency chopper was used to simulate a pulsed laser signal, and an oscilloscope was used to collect the photoelectric response signal. A reverse voltage of -15 V was applied to both ends (two metal electrodes) of the multifunctional device prepared in Example 5 of the present invention. The laser was incident perpendicular to the substrate direction of the device. The current-voltage curve of the multifunctional device prepared in Example 5 of the present invention to 405 nm incident light was tested. The test results are as follows: Figure 8 As shown by Figure 8 It can be seen that the multifunctional device prepared by the present invention is used as a photoelectric detector, and the photoelectric response signal is very strong, and the photoelectric response can reach up to 1500 (A / W). At present, the content index of commercial photodiodes is only about 1 (A / W). At the same time, the device provided by the present invention responds very quickly, and the response time is about 10ms.

[0084] Example 6

[0085] A multifunctional device is prepared according to the method described in Example 1. The difference from Example 1 is that two-dimensional molybdenum disulfide is used to replace the graphene in Example 1. The preparation method of the two-dimensional material film molybdenum disulfide is:

[0086] Molybdenum disulfide is prepared by dual-temperature zone chemical vapor deposition. First, the tube body is cleaned with high-purity argon gas, high-purity sulfur powder is placed in the front low-temperature zone, and high-purity molybdenum oxide is placed in the rear high-temperature zone. The substrate for growing molybdenum disulfide is a single-sided polished silicon oxide / silicon wafer, which is cleaned and placed above the molybdenum oxide in the high-temperature zone. The two temperature zones are heated separately, and the required molybdenum disulfide film can be obtained in about half an hour.

[0087] A high-frequency chopper was used to simulate a pulsed laser signal, and an oscilloscope was used to collect the photoelectric response signal. A reverse voltage of -15 V was applied to both ends (two metal electrodes) of the multifunctional device prepared in Example 6 of the present invention. The laser was incident perpendicular to the substrate direction of the device. The current-voltage curve of the multifunctional device prepared in Example 6 of the present invention to 532 nm incident light was tested. The test results are as follows: Fig. 9 As shown by Fig. 9It can be seen that the multifunctional device prepared in the embodiment of the present invention is used as a photoelectric detector, the photoelectric response signal is very strong, the photoelectric response can reach up to 1600 (A / W), and the response is very fast.

[0088] It can be seen from the above embodiments that the present invention provides a multifunctional device, including a substrate, a thin film electrode, quantum dot colloidal particles, and a metal electrode. The present invention obtains a multifunctional device on a substrate by disconnecting a strip-shaped two-dimensional material film and reconnecting the disconnected film with colloidal quantum dots under the action of an external driving voltage, and finally forms a special planar structure of two-dimensional material film / quantum dots / two-dimensional material film. The multifunctional device provided by the present invention has functions similar to traditional photodiodes and has excellent rectification characteristics and photoelectric detection performance. The difference between the multifunctional device provided by the present invention and traditional semiconductor photodiodes is that its performance is less affected by temperature and has a very high photoelectric response. At the same time, the preparation method of the multifunctional device provided by the present invention is simple in process, has no selection of substrates, and has a wide range of raw materials for two-dimensional material films and quantum dots, is easy to prepare, has low cost, is environmentally friendly, and is suitable for industrial production.

[0089] The above embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention. At the same time, the description of the above embodiments is only used to help understand the method of the present invention and its core idea. For ordinary technicians in this field, according to the idea of ​​the present invention, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation of the present invention.

Claims

1. A multifunctional device comprising: substrate; A first thin film electrode disposed on the surface of the substrate; A second thin film electrode disposed on the surface of the substrate; The material of the first thin film electrode and the second thin film electrode is selected from graphene or monolayer molybdenum disulfide; The first thin film electrode and the second thin film electrode are arranged on the substrate surface at intervals and connected by quantum dot colloid particles; the quantum dot colloid particles are carbon quantum dot colloid particles or gold quantum dot colloid particles; the quantum dot colloid particles present a concentration gradient between the first thin film electrode and the second thin film electrode; A portion of the first metal electrode is disposed on the surface of the first thin film electrode, and another portion of the first metal electrode is disposed on the surface of the substrate; A portion of the second metal electrode is disposed on the surface of the second thin film electrode, and another portion of the second metal electrode is disposed on the surface of the substrate.

2. The multifunctional device according to claim 1, characterized in that The shortest distance between the first thin film electrode and the second thin film electrode is 5 to 30 micrometers.

3. The multifunctional device according to claim 1, characterized in that The material of the substrate is selected from silicon, silicon oxide, glass or plastic.

4. The multifunctional device according to claim 3, characterized in that The plastic component is selected from polyimide, polyethylene naphthalate or polyethylene terephthalate.

5. A method for preparing the multifunctional device according to claim 1, comprising: Prepare a first thin film electrode and a second thin film electrode which are not in contact with each other on the surface of the substrate; The quantum dot colloidal particle solution is disposed between the first thin film electrode and the second thin film electrode, and an electric field is applied to the quantum dot colloidal particle solution to realize the assembly of the quantum dot colloidal particles between the first thin film electrode and the second thin film electrode, so that the quantum dot colloidal particles present a concentration gradient between the first thin film electrode and the second thin film electrode and connect the first thin film electrode and the second thin film electrode; Disposing a first metal electrode on the first film electrode and the surface of the substrate; A second metal electrode is disposed on the second film electrode and the surface of the substrate.

6. The method according to claim 5, characterized in that The externally applied electric field is a constant voltage electric field.

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