Infrared imaging detector based on thermoelectric effect of perovskite material and preparation method thereof

Abstract

The invention belongs to the technical field of detectors, and relates to an infrared imaging detector based on the thermoelectric effect of a perovskite material and a preparation method thereof, and the preparation method comprises the steps: carrying out the spin coating or blade coating of a carbon paste electrode layer on one surface of the perovskite material, and carrying out the evaporation of a metal electrode layer on the other surface of the perovskite material, enabling the metal electrode layer to be connected with an electrode on the corresponding TFT circuit or CMOS circuit; and connecting the TFT circuit or the CMOS circuit with an external display to obtain the infrared imaging detector. The photo-thermal electric detector prepared by the invention has no transverse charge migration, reduces signal crosstalk, and improves the imaging quality.

Description

Technical Field

[0001] This application belongs to the technical field of detectors, and more specifically, relates to an infrared imaging detector based on the thermoelectric effect of perovskite materials and a preparation method thereof. Background Art

[0002] Infrared thermal imaging detectors can be applied not only in fields such as satellite navigation and autonomous driving, but also in directions such as food safety detection and drug component analysis. Therefore, developing low-cost, high-quality, and stable-performance infrared thermal imaging detectors is one of the important current directions. At present, the infrared detectors mainly prepared from III-V group materials such as InGaAs on the market not only have complex preparation processes and high costs, but also the detection accuracy is easily affected by factors such as noise and signal crosstalk, resulting in low image quality of the detection. In recent years, the emerging perovskite materials are a new type of semiconductor material with excellent optoelectronic properties. Moreover, due to the high resistivity exhibited by perovskite materials, such as the resistance of MAPbI3 thin films reaching about 100 MΩ, and low thermal conductivity, a very large Seebeck coefficient and thermoelectric voltage can be generated. Therefore, it is necessary to explore a method for preparing an infrared imaging detector with high imaging quality using this new semiconductor material. Summary of the Invention

[0003] Aiming at the defects of the prior art, the purpose of this application is to provide an infrared imaging detector based on the thermoelectric effect of perovskite materials and a preparation method thereof, aiming to solve problems such as insufficient detection accuracy, high noise, and large lateral carrier crosstalk of existing infrared detection devices.

[0004] To achieve the above purpose, in the first aspect, this application provides a preparation method of an infrared imaging detector based on the thermoelectric effect of perovskite materials, and the preparation method includes: S1 Evaporating a metal electrode layer on one surface of a cuboid-shaped perovskite crystal; S2 Spin-coating or blade-coating a carbon paste electrode layer on the side of the perovskite crystal facing away from the metal electrode layer; S3 Connecting the metal electrode layer to the electrode on the TFT circuit; S4 Connecting the TFT circuit to an external display to obtain an infrared imaging detector.

[0005] Further, in step S1, the long side of the perovskite crystal is 1 cm to 2 cm.

[0006] Further, in step S2, the material of the metal electrode layer is gold, silver, copper, or indium tin oxide, and the thickness of the metal electrode layer is 50 nm to 80 nm.

[0007] Further, the material of the carbon paste electrode layer is aminated carbon; and / or, the thickness of the carbon paste electrode layer is 1 μm to 2 μm; and / or, the TFT circuit is a voltage-type signal access circuit.

[0008] In one aspect, the present application provides a method for preparing an infrared imaging detector based on the thermoelectric effect of perovskite materials, and the preparation method includes: S1 Prepare a carbon paste electrode layer, and prepare a layer of perovskite film on the carbon paste electrode layer; S2 Evaporate a metal electrode layer on the perovskite film; S3 Connect the metal electrode layer to the electrode on the CMOS circuit; S4 Connect the CMOS circuit to an external display to obtain an infrared imaging detector.

[0009] Further, the thickness of the perovskite film is 1 μm to 5 μm.

[0010] Further, in step S3, the CMOS circuit is a voltage-type signal access circuit.

[0011] Further, the material of the carbon paste electrode layer is aminated carbon, and the thickness of the carbon paste electrode layer is 1 μm to 2 μm.

[0012] Further, in step S2, the material of the metal electrode layer is gold, silver, copper or indium tin oxide, and the thickness of the metal electrode layer is 50 nm to 80 nm.

[0013] In a third aspect, an infrared imaging detector prepared by using the preparation method as described above is disclosed. The infrared imaging detector includes a metal electrode layer, a perovskite material layer and a carbon paste electrode layer which are sequentially stacked, and further includes a signal access circuit connected to the metal electrode layer, and an external display connected to the electrode of the signal access circuit.

[0014] It can be understood that the beneficial effects of the above second aspect can be referred to the relevant descriptions in the above first aspect, and will not be repeated here.

[0015] Generally speaking, compared with the prior art by the above technical solutions conceived by the present application, the following beneficial effects are obtained: (1) In this application, different perovskite materials are selected as thermoelectric materials, and the electrode structure is optimized by preparing a carbon paste electrode layer. The preparation cost is lower and the preparation process is simpler, which is especially suitable for the preparation of large-area devices. In addition, the integration compatibility between perovskite crystals and TFT circuits (Thin Film Transistor, TFT) is higher, and they have the properties of high carrier mobility and low defect density, which is more conducive to improving the sensitivity and response speed performance of photodetectors. The integration of perovskite thin film technology and CMOS circuits (Complementary Metal-Oxide-Semiconductor, CMOS) can prepare devices with higher spatial resolution and imaging quality, and clearer detection images can be obtained.

[0016] (2) The photodetector prepared in this application has small energy loss and more accurate detection. In optothermal imaging detection, the internal quantum conversion efficiency in the optothermal energy conversion process of this application can be as high as 100%. There is no lateral charge migration, reducing signal crosstalk. All light energy is absorbed and then converted into electrical energy through heat energy, which can greatly improve the detection accuracy.

[0017] (3) The preparation method of this application is simpler and more efficient than the traditional method of manufacturing detectors using Micro-Electro-Mechanical Systems (MEMS). The response of the prepared infrared detector is also higher than that of existing optothermal detectors with graphene thin film structures under the same test environment. Description of the Drawings

[0018] Figure 1 is one of the schematic flowcharts of the preparation method of the infrared imaging detector based on the thermoelectric effect of perovskite materials provided by this application; Figure 2 is another schematic flowchart of the preparation method of the infrared imaging detector based on the thermoelectric effect of perovskite materials provided by this application; Figure 3 is the schematic structural diagram of the infrared imaging detector based on the thermoelectric effect of perovskite materials provided by this application; Figure 4 is the schematic diagram of the measurement results of the infrared imaging detector prepared by the preparation method provided in Example 1 of this application; Figure 5 is the schematic diagram of the response values of the infrared imaging detector provided in Example 1 of this application to 980 nm, 1300 nm, and 2200 nm infrared lasers; Figure 6 is the schematic diagram of the measurement results of the infrared imaging detector prepared by the preparation method provided in Example 2 of this application. Detailed Description of the Embodiments

[0019] To make the objectives, technical solutions and advantages of this application more clear and understandable, the following further details this application in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit this application.

[0020] The term "and / or" in this document describes the association relationship of associated objects and indicates that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. The symbol " / " in this document indicates that the associated objects are in an "or" relationship. For example, A / B represents A or B.

[0021] The terms "first", "second", etc. in the description and claims of this application are used to distinguish different objects, rather than to describe a specific order of the objects. For example, the first response message and the second response message are used to distinguish different response messages, rather than to describe the specific order of the response messages.

[0022] In the embodiments of this application, words such as "exemplary" or "for example" are used to give examples, illustrations or explanations. Any embodiment or design solution described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or having more advantages than other embodiments or design solutions. Rather, the use of words such as "exemplary" or "for example" is intended to present relevant concepts in a specific manner.

[0023] In the description of the embodiments of this application, unless otherwise specified, the meaning of "a plurality of" refers to two or more. For example, a plurality of processing units refers to two or more processing units, etc.; a plurality of elements refers to two or more elements, etc.

[0024] In the preparation method of the infrared imaging detector based on the thermoelectric effect of perovskite materials provided by this application, methods such as saturated temperature-drop crystallization method and inverse-temperature growth crystallization method are used to prepare perovskite crystals, and methods such as spin coating or screen printing are used to prepare perovskite films. The molecular formula of perovskite is of the ABX3 structure, where A is methylamine (MA), formamidine (FA), etc., B is lead, tin, etc., and X is iodine, chlorine, bromine, etc. For example: MAPbI3, FAPbI3, MA X FA 1-X PbI3, FA X Cs 1-X PbI3, etc.

[0025] Such as Figure 1As shown, if a perovskite crystal is selected as the photothermal material, the perovskite crystal is in the shape of a cuboid, and its longest side length is 1 cm to 2 cm, that is, the length of the cuboid is 1 cm to 2 cm. During the preparation process, a metal electrode layer needs to be evaporated on the upper surface of the perovskite crystal first. The material of the metal electrode layer is gold, silver, copper or indium tin oxide, and the thickness of the metal electrode layer is 50 nm to 80 nm, such as 50 nm, 60 nm, 70 nm or 80 nm, or any thickness between any two of the above thickness values. Then, a carbon paste electrode layer is spin-coated or scrape-coated on the lower surface of the perovskite crystal. The material of the carbon paste electrode layer is amino-functionalized carbon; the thickness of the carbon paste electrode layer is 1 μm to 2 μm, such as 1 μm, 1.5 μm or 2 μm, so as to assemble a device structure in which a three-layer structure of carbon, MAPbI3, and metal is stacked from bottom to top. Then, a plurality of such device structures are arranged in an array form, and the metal electrode layer is connected to the electrode on the TFT circuit by means of flip-chip bonding. Finally, the TFT circuit is connected to an external display to obtain a photothermal detector.

[0026] such as Figure 2 As shown, if a perovskite film is selected as the photothermal material, a perovskite film layer needs to be prepared on a glass substrate with a carbon paste electrode layer first. The carbon paste electrode layer is an amino-functionalized carbon electrode, and the thickness of the carbon paste electrode layer is 1 μm to 2 μm, such as 1 μm, 1.5 μm or 2 μm, or any thickness between any two of the above thicknesses. Then, a metal electrode layer is evaporated on the side of the perovskite film layer away from the glass substrate. Among them, the material of the metal electrode layer is gold, silver, copper or indium tin oxide, and the thickness of the metal electrode layer is 50 nm to 80 nm, such as 50 nm, 60 nm, 70 nm or 80 nm, or any thickness between any two of the above thickness values. The thickness of the aforementioned perovskite film is 1 μm to 5 μm, such as 1 μm, 2 μm, 3 μm, 4 μm or 5 μm, or any thickness value between any two of the above thickness values. A device structure including carbon, MAPbI3, and metal in sequence from bottom to top is prepared in the above manner. Then, the electrodes on the perovskite film are prepared into the same size as the electrodes on the CMOS (Complementary Metal-Oxide-Semiconductor) circuit by means of laser scribing and etching. Then, the metal electrode layer is connected to the electrode on the CMOS circuit by means of bonding. Finally, the CMOS circuit is connected to an external display to obtain a photothermal imaging detector.

[0027] The above two preparation methods prepare such as Figure 3The detector structure shown successively includes a carbon electrode layer, a MAPbI3 single crystal layer or a MAPbI3 thick film layer, and a metal electrode layer (i.e., a metal electrode layer or a metal electrode layer). The detector structure has a high sensitivity of 0.58 V / W and good infrared image resolution. The overall preparation method is simpler than that of traditional detectors manufactured by microelectromechanical systems (MEMS), and the response of the detector is also higher than that of the thin film structure photothermal-electric detector.

[0028] The embodiments of the present application will be described below with reference to the accompanying drawings in the embodiments of the present application.

[0029] Example 1 MAPbI3 perovskite crystals were grown by the inverse temperature crystallization method. The long side of the perovskite crystal was 1 cm, the width was half of the length, i.e., 0.5 cm, and the height was approximately half of the width, i.e., 0.25 cm. An amino-functionalized carbon with a thickness of 1 μm was deposited on one side of the perovskite crystal as an electrode light-absorbing layer, and a gold electrode with a thickness of 50 nm was evaporated on the other end. As Figure 4 shown, the amino-functionalized carbon electrode can absorb infrared light and convert it into heat, generating a potential difference through photothermal-electric conversion. Then, the perovskite crystals were formed into a 3×3 array, and the metal electrodes on the lower layer of the perovskite crystal array were connected to the metal electrodes on the TFT circuit board by flip-chip bonding to form a photothermal-electric detector.

[0030] To avoid the photovoltaic effect, the infrared response needs to be measured under dark conditions. Infrared lasers with multiple different wavelengths within the range of 980 nm to 2200 nm were used as light sources, such as infrared lasers at 980 nm, 1300 nm, and 2200 nm. The photothermal-electric detector based on the carbon / MAPbI3 single crystal / metal structure showed a stable response in the range of 980 nm to 2200 nm. As Figure 4 shown in Figure (a) therein, the photothermal-electric detector generates a temperature difference on the upper and lower surfaces of the perovskite crystal by absorbing solar heat or thermal energy (absorbed by the carbon paste electrode layer). As Figure 4 shown in Figure (b) therein, according to the Seebeck effect, different temperature differences can generate potential differences. Different electrodes are different pixel points, which can generate different voltages and be collected by the TFT circuit, and then the detection signal can be displayed through an external display.

[0031] As Figure 5As shown in (a) - (c), the response values of the photothermal detector to 980 nm, 1300 nm, and 2200 nm infrared lasers are 0.58 V / W, 0.51 V / W, and 0.22 V / W, respectively. This different power - voltage response to different wavelengths of light can be input into the TFT circuit at the lower end and then connected to a display for image display. The infrared thermoelectric imaging device with this structure is much easier to fabricate than traditional detectors made of micro - electro - mechanical systems (MEMS). The response is also higher than that of photothermal detectors with thin - film structures such as graphene.

[0032] Example 2 Different from Example 1, in this example, cubic - shaped FAPbI3 perovskite crystals with a side length of 1.5 cm were grown by the inverse - temperature crystallization method. A carbon layer with a thickness of 2 μm was deposited on one end face of the FAPbI3 crystal as an electrode light - absorbing layer (i.e., a carbon - paste electrode layer), and a metal electrode layer with a thickness of 60 nm was evaporated on the other end. Then, the perovskite crystals were formed into a 3×3 array, and the metal electrodes under the perovskite crystals were connected to the metal electrodes on the TFT circuit board through flip - chip bonding to obtain a photothermal detector. The carbon - paste electrode layer absorbs infrared light and converts it into heat, generating a temperature difference through photothermal conversion. According to the Seebeck effect, as Figure 6 shown, different temperature differences can generate potential differences, and different electrodes are different pixel points, which can generate different voltages.

[0033] To avoid the photovoltaic effect, the infrared response was measured under dark conditions. Different - wavelength infrared lasers were used as light sources for measurement, and the wavelength range was from 980 nm to 2200 nm. It was found that the carbon / FAPbI3 single - crystal / metal - based multi - layer - structured photothermal detector showed a stable response in the range of 980 nm to 2200 nm. Specifically, the response values to 980 nm, 1300 nm, and 2200 nm infrared lasers are 0.72 V / W, 0.61 V / W, and 0.33 V / W, respectively (not shown in the figure). This different power - voltage response to different wavelengths of light can be input into the TFT circuit and then connected to a display for image display.

[0034] Example 3 In this example, a 5 - μm - thick perovskite film layer was prepared on a glass substrate with a carbon - paste electrode by methods such as spin - coating (or screen - printing or evaporation), and then a metal electrode layer was evaporated on the perovskite film layer. The thickness of the carbon - paste electrode layer is 2 μm, and the material of the carbon - paste electrode layer is amino - functionalized carbon. The perovskite film layer structure is MAPbI 3。The metal electrode layer is silver, and the thickness of the metal electrode layer is 50 nm. Then, laser scribing etching is used to make the size of the metal electrode layer consistent with the electrode size on the CMOS circuit, and they are well connected by bonding. In this device, the carbon paste electrode layer at the upper end of the MAPbI3 thick film absorbs infrared light and converts it into heat, forming a temperature difference at both ends of the MAPbI3, and then generating a potential difference through the Seebeck effect.

[0035] To avoid the photovoltaic effect, in this embodiment, the infrared response is measured under dark conditions, and different wavelengths of infrared lasers are used as light sources for measurement, with the wavelength in the range of 980 nm to 2200 nm. The optoelectrothermal detector with a carbon / MAPbI3 thick film / metal substrate structure shows a stable response in the range of 980 nm to 2200 nm. Specifically, the response values of the optoelectrothermal detector to 980 nm, 1300 nm, and 2200 nm infrared lasers are 0.45 V / W, 0.32 V / W, and 0.16 V / W, respectively. This different power voltage reflected by different wavelengths of light can be input into the lower CMOS circuit and then connected to a display for image display.

[0036] Example 4 In this embodiment, a perovskite film layer is prepared on a glass substrate with a carbon paste electrode layer by methods such as spin coating (or screen printing or evaporation), and then a metal electrode layer is evaporated on the perovskite film layer. The carbon paste electrode layer is amino-functionalized carbon, the thickness of the carbon paste electrode layer is 1 μm, the thickness of the perovskite film layer is 3 μm, and the structure of the perovskite film layer is FA X Cs 1-X PbI3. The metal electrode layer is copper, and the thickness of the metal electrode layer is 70 nm. The laser scribing etching method is also used to make the size of the metal electrode layer consistent with the electrode size on the CMOS circuit, and then they are firmly connected by bonding. In the optoelectrothermal detector prepared in this embodiment, FA X Cs 1-X A carbon paste layer is coated on the upper end of the PbI3 thick film to absorb infrared light and convert it into heat, forming a temperature difference at both ends of FA X Cs 1-X PbI3, and then generating a potential difference through the Seebeck effect.

[0037] To avoid the photovoltaic effect, in this embodiment, the infrared response is measured under dark conditions, and different wavelengths of infrared lasers are used as light sources for measurement, with the wavelength in the range of 980 nm to 2200 nm. The structural layers are, in sequence, the light source carbon, FA X Cs 1- XThe PbI3 thick film and the metal-based structure photothermal detector exhibit stable responses, and the response values to 980 nm, 1300 nm, and 2200 nm infrared lasers are 0.98 V / W, 0.81 V / W, and 0.52 V / W respectively. This different power voltage reflected by light of different wavelengths can be input into the CMOS circuit and then the image can be displayed through an external display.

[0038] It should be understood that expressions such as "including" and "may include" that can be used in this application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In this application, terms such as "including" and / or "having" can be interpreted as indicating a specific characteristic, number, operation, constituent element, component, or a combination thereof, but cannot be interpreted as excluding the existence or possibility of addition of one or more other characteristics, numbers, operations, constituent elements, components, or a combination thereof.

[0039] In addition, in this application, the expression "and / or" includes any and all combinations of the associated listed words. For example, the expression "A and / or B" can include A, can include B, or can include both A and B.

[0040] In the description of the embodiments of this application, it should be noted that unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. Among them, "fixed connection" means that they are connected to each other and the relative position relationship after connection remains unchanged. "Rotational connection" means that they are connected to each other and can rotate relative to each other after connection. "Sliding connection" means that they are connected to each other and can slide relative to each other after connection. The orientation terms mentioned in the embodiments of this application, such as "top", "bottom", "inside", "outside", "left", "right", etc., are only with reference to the direction of the drawings. Therefore, the orientation terms used are for better and clearer description and understanding of the embodiments of this application, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation on the embodiments of this application.

[0041] In addition, in the embodiments of the present application, mathematical concepts such as symmetry, equality, parallelism, and perpendicularity are mentioned. These definitions are all based on the current technological level, rather than the absolutely strict definitions in the mathematical sense. A small deviation is allowed, and being approximately symmetric, approximately equal, approximately parallel, approximately perpendicular, etc. are all acceptable. For example, if A is parallel to B, it means that A is parallel to B or approximately parallel to B, and the included angle between A and B can be between 0 degrees and 10 degrees. If A is perpendicular to B, it means that A is perpendicular to B or approximately perpendicular to B, and the included angle between A and B can be between 80 degrees and 100 degrees.

[0042] As described above, the foregoing is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should all be covered within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A method for preparing an infrared imaging detector based on the thermoelectric effect of perovskite materials, characterized in that The preparation method includes: S1 Evaporating a metal electrode layer on one surface of a perovskite crystal in the shape of a cuboid; S2 Spin-coating or blade-coating a carbon paste electrode layer on the surface of the perovskite crystal facing away from the metal electrode layer; S3 Connecting the metal electrode layer to the electrode on the TFT circuit; S4 Connecting the TFT circuit to an external display to obtain an infrared imaging detector.

2. The preparation method according to claim 1, characterized in that, In step S1, the long side of the perovskite crystal is 1 cm to 2 cm.

3. The preparation method according to claim 1, wherein In step S2, the material of the metal electrode layer is gold, silver, copper or indium tin oxide, and the thickness of the metal electrode layer is 50 nm to 80 nm.

4. The preparation method according to claim 1, wherein, The material of the carbon paste electrode layer is amino-carbon; and / or, the thickness of the carbon paste electrode layer is 1 μm to 2 μm; and / or, the TFT circuit is a voltage-type signal access circuit.

5. A method for preparing an infrared imaging detector based on the thermoelectric effect of perovskite materials, characterized in that, The preparation method includes: S1 Preparing a carbon paste electrode layer and preparing a perovskite film on the carbon paste electrode layer; S2 Evaporating a metal electrode layer on the perovskite film; S3 Connecting the metal electrode layer to the electrode on the CMOS circuit; S4 Connecting the CMOS circuit to an external display to obtain an infrared imaging detector.

6. The preparation method according to claim 5, characterized in that, In step S1, the thickness of the perovskite film is 1 μm to 5 μm.

7. The preparation method according to claim 5, characterized in that, In step S3, the CMOS circuit is a voltage-type signal access circuit.

8. The preparation method according to claim 5, characterized in that, The material of the carbon paste electrode layer is amino-carbon, and the thickness of the carbon paste electrode layer is 1 μm to 2 μm.

9. The preparation method according to claim 5, characterized in that, In step S2, the material of the metal electrode layer is gold, silver, copper or indium tin oxide, and the thickness of the metal electrode layer is 50 nm to 80 nm.

10. An infrared imaging detector prepared by the preparation method according to any one of claims 1-9, characterized in that, The infrared imaging detector includes a metal electrode layer, a perovskite material layer and a carbon paste electrode layer stacked in sequence, and further includes a signal access circuit connected to the metal electrode layer, and an external display connected to the electrode of the signal access circuit.

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