Infrared hyperspectral imaging detector and preparation method and imaging method thereof

Abstract

The invention relates to an infrared hyperspectral imaging detector and a preparation method and an imaging method thereof, and belongs to the field of infrared detection. The infrared hyperspectral imaging detector comprises a reading circuit, a colloidal quantum dot infrared detection unit and a random optical filter array, wherein the reading circuit is provided with pixel circuits which are arranged in an array; the colloidal quantum dot infrared detection unit is coupled to one side of the reading circuit; the colloidal quantum dot infrared detection units are arranged on one side of the reading circuit in an array mode. The random optical filter array is coupled to one side, deviating from the reading circuit, of the colloidal quantum dot infrared detection unit; the random optical filter array comprises optical filters arranged in an array mode, the different optical filters have different light-transmitting wavebands, and the light-transmitting wavebands of the optical filters are within the detection wavelength ranges of the corresponding colloidal quantum dot infrared detection units. Therefore, the random filter array is directly coupled with the area array reading circuit coupled with the colloidal quantum dot infrared detection unit, the structure is simplified, real-time imaging can be realized, and the spatial resolution is improved.

Description

Technical Field

[0001] The present disclosure relates to the field of photoelectric detection technology, and in particular to an infrared hyperspectral imaging detector and a preparation method and imaging method thereof. Background Art

[0002] In the field of photoelectric sensors and photoelectric detection, hyperspectral infrared imagers / detectors are a key application in photoelectric sensors. Hyperspectral infrared imagers can capture spectral information across different wavelengths, including important information such as the energy distribution of photons within these wavelengths. Therefore, they play a crucial role in fields such as biomedicine, chemical and physical property analysis, and thermal and temperature distribution analysis. Unlike conventional three-channel visible light sensors (red, green, and blue) or wide-band infrared detectors, which lose information across a significant range of wavelengths, hyperspectral infrared detectors utilize narrower channels to capture hyperspectral information across various wavelengths within the infrared range. Hyperspectral infrared detectors are able to capture spectral information across a continuous narrowband of a target object. Compared to the minute spectral differences that traditional detectors cannot discern, hyperspectral sensors can capture continuous and detailed spectral information. By matching spectral features, they can identify specific materials. Furthermore, through algorithmic fusion, hyperspectral imaging can be achieved to analyze the proportions of various components. These detectors have important applications in industrial inspection, agriculture, environmental monitoring, and the military.

[0003] The hyperspectral detectors in the related art have the following problems: First, the hyperspectral array detectors in the related art are generally photoelectric detectors based on silicon materials, which are usually used in the visible light band and cannot detect the infrared band. The detectors extended to the infrared band are usually single-point imaging systems, which rely on scanning imaging or coded imaging to achieve hyperspectral imaging, with long imaging time and low resolution; second, infrared bulk materials with different response bands are difficult to integrate into the same readout circuit substrate, and traditional bulk materials that achieve infrared response are limited by the flip-chip bonding process and cannot be directly coupled with the filter. A front optical system is usually required for spectrometry, which increases the complexity of the optical system; third, hyperspectral imaging detectors based on spectrometry need to acquire data through spatial or spectral scanning, with low frame rate and slow speed, and cannot achieve real-time imaging; fourth, although hyperspectral infrared detectors based on pixel-level filter method can achieve real-time imaging, it will lead to a serious decrease in spatial resolution. Summary of the Invention

[0004] In order to solve the above technical problems or at least partially solve the above technical problems, the present disclosure provides an infrared hyperspectral imaging detector, a preparation method thereof, and an imaging method.

[0005] The present disclosure provides an infrared hyperspectral imaging detector, comprising: A readout circuit having pixel circuits arranged in an array; A colloidal quantum dot infrared detection unit is coupled to one side of the readout circuit; the colloidal quantum dot infrared detection units are arranged in an array on one side of the readout circuit; A random filter array is coupled to the side of the colloidal quantum dot infrared detection unit away from the readout circuit; the random filter array includes filters arranged in an array, different filters have different light transmission bands, and the light transmission bands of the filters are within the detection wavelength range of the corresponding colloidal quantum dot infrared detection unit.

[0006] Optionally, the optical filter includes a first type of optical filter and a second type of optical filter; Along the direction of the readout circuit pointing to the random filter array, the first type of filter includes two distributed Bragg reflectors arranged opposite to each other and an optical cavity located between the two distributed Bragg reflectors, and the second type of filter includes one distributed Bragg reflector and an optical cavity; The thickness of the optical cavity of different first-type filters is different, and the thickness of the optical cavity of different second-type filters is different.

[0007] Optionally, the size of the optical cavity is consistent with the size of the corresponding coupled pixel circuit.

[0008] Optionally, the number of the first type of filters is the same as the number of the second type of filters.

[0009] Optionally, the colloidal quantum dot infrared detection unit includes a first electrode, a second electrode and a colloidal quantum dot layer, the first electrode and the second electrode are arranged relative to each other in a plane parallel to the readout circuit, and the colloidal quantum dot layer is located on the side of the first electrode and the second electrode away from the readout circuit, and is filled between the first electrode and the second electrode.

[0010] Optionally, the colloidal quantum dot infrared detection unit includes a third electrode, a first type doped layer, a colloidal quantum dot layer, a second type doped layer and a fourth electrode stacked along the direction of the readout circuit pointing to the random filter array, and the first type doped layer and the second type doped layer are respectively one of an N-type doped layer and a P-type doped layer, and the two are different.

[0011] Optionally, the material of the colloidal quantum dot layer includes one of lead sulfide, lead selenide, lead telluride, cadmium sulfide, cadmium selenide, mercury telluride, mercury selenide, mercury sulfide, silver telluride, silver sulfide and silver selenide; The first electrode and the second electrode are metal electrodes, the third electrode is a metal electrode or a transparent electrode, and the fourth electrode is a transparent electrode; wherein the material of the metal electrode includes one of platinum, gold, silver, copper, aluminum, and chromium, and the material of the transparent electrode includes one of indium tin oxide and fluorine-doped tin dioxide; The material of the N-type doping layer includes one of bismuth selenide, bismuth sulfide, bismuth telluride, zinc oxide, cadmium selenide, titanium dioxide, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, methyl butyrate, and N-type quantum dots that are the same as the colloidal quantum dot layer material; The material of the P-type doping layer includes silver telluride, poly (3,4-ethylenedioxythiophene) polystyrene sulfonate, poly 3-hexylthiophene, 2,2',7,7'-tetrakis [N,N-bis (4-methoxyphenyl) amino] -9,9'-spirobifluorene, polytriarylamine, nickel oxide, zinc telluride, C 60 and one of the P-type quantum dots that are the same material as the colloidal quantum dot layer.

[0012] The present disclosure also provides a method for preparing an infrared hyperspectral imaging detector, which is used to form any of the above-mentioned infrared hyperspectral imaging detectors; the method for preparing the infrared hyperspectral imaging detector comprises: Providing and cleaning a readout circuit; the readout circuit has pixel circuits arranged in an array; A colloidal quantum dot infrared detection unit is prepared on one side of the readout circuit; the colloidal quantum dot infrared detection unit is arranged in an array on one side of the readout circuit; A random filter array is coupled to the side of the colloidal quantum dot infrared detection unit facing away from the readout circuit; the random filter array includes filters arranged in an array, different filters have different light transmission bands, and the light transmission bands of the filters are within the detection wavelength range of the corresponding colloidal quantum dot infrared detection unit.

[0013] Optionally, the preparation of the colloidal quantum dot infrared detection unit includes: forming a preset electrode layer on one side of the readout circuit; performing patterning on the preset electrode layer to form a first electrode and a second electrode, wherein the first electrode and the second electrode are arranged opposite to each other in a plane parallel to the plane where the readout circuit is located; forming a colloidal quantum dot layer on a side of the first electrode and the second electrode facing away from the readout circuit by spin coating, drop coating, spray coating, blade coating or evaporation, wherein the colloidal quantum dot layer is also filled between the first electrode and the second electrode; or, The method for preparing a colloidal quantum dot infrared detection unit comprises: forming a third electrode on one side of the readout circuit; forming a first type doping layer on a side of the third electrode facing away from the readout circuit by using a film forming method such as drop coating, spin coating, spray coating, blade coating or evaporation; forming a colloidal quantum dot layer on a side of the first type doped layer facing away from the third electrode by spin coating, drop coating, spray coating, blade coating or evaporation; On a side of the colloidal quantum dot layer facing away from the first type doping layer, forming a second type doping layer by using a film forming method such as drop coating, spin coating, spray coating, blade coating or evaporation; On the side of the second-type doping layer away from the colloidal quantum dot layer, a fourth electrode is formed by using a film forming method such as thermal evaporation, magnetron sputtering, or atomic layer deposition.

[0014] Optionally, the coupled random filter array includes: The random filter arrays are coupled by glue curing or welding.

[0015] The present disclosure also provides an imaging method of an infrared hyperspectral imaging detector, which is performed based on any of the above-mentioned infrared hyperspectral imaging detectors.

[0016] The technical solution provided by the present disclosure has the following advantages compared with the existing technology: The infrared hyperspectral imaging detector provided by the present invention includes a readout circuit, a colloidal quantum dot infrared detection unit and a random filter array, wherein the readout circuit has an array-arranged pixel circuit; the colloidal quantum dot infrared detection unit is coupled to one side of the readout circuit; the colloidal quantum dot infrared detection unit is arranged in an array on one side of the readout circuit; the random filter array is coupled to the side of the colloidal quantum dot infrared detection unit away from the readout circuit; the random filter array includes filters arranged in an array, different filters have different transmittance bands, and the transmittance bands of the filters are within the detection wavelength range of the corresponding colloidal quantum dot infrared detection unit. Thus, the colloidal quantum dot infrared detection unit can be directly coupled with the area array readout circuit to realize area array infrared imaging, thereby eliminating the need for scanning or encoding, achieving real-time imaging, high imaging efficiency, and high image resolution; at the same time, by setting the detection unit as a colloidal quantum dot detection unit, the integration of colloidal quantum dot detection units with different response bands can be realized, and the colloidal quantum dots can be directly coupled to the readout circuit without the need for a flip-chip bonding coupling method, which is low in cost; and there is no flip-chip solder base above the colloidal quantum dot infrared detection unit, so it can be directly coupled with the filter to achieve hyperspectral detection; at the same time, by directly coupling the filter with the readout circuit coated with colloidal quantum dots, the filter can be selectively transparent, eliminating the need for spectroscopic scanning, simplifying the structure of the optical system and the imaging detector, and the hyperspectral image can be directly output, with a fast imaging speed and real-time imaging; in addition, a random filter array composed of Fabry-Perot (FP) filters is used as an encoding mask, and efficient information compression is achieved through random spatial-spectral encoding, thereby achieving real-time and high-resolution hyperspectral imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0018] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0019] Figure 1 A schematic structural diagram of an infrared hyperspectral imaging detector provided in an embodiment of the present disclosure; Figure 2 A schematic diagram of the working principle of a filter in an infrared hyperspectral imaging detector provided by an embodiment of the present disclosure; Figure 3A schematic structural diagram of a random filter array in an infrared hyperspectral imaging detector provided by an embodiment of the present disclosure; Figure 4 A schematic diagram of the structure of a single pixel in an infrared hyperspectral imaging detector provided in an embodiment of the present disclosure; Figure 5 A schematic diagram of another single-pixel structure in an infrared hyperspectral imaging detector provided in an embodiment of the present disclosure; Figure 6 A schematic diagram of the transmittance of a random filter array in an infrared hyperspectral imaging detector provided by an embodiment of the present disclosure; Figure 7 A schematic diagram of the imaging principle of the infrared hyperspectral imaging detector provided in an embodiment of the present disclosure; Figure 8 A schematic flow chart of a method for preparing an infrared hyperspectral imaging detector provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0020] In order to more clearly understand the above-mentioned objectives, features and advantages of the present disclosure, the scheme of the present disclosure will be further described below. It should be noted that the embodiments of the present disclosure and the features therein can be combined with each other in the absence of conflict.

[0021] In the following description, many specific details are set forth to facilitate a full understanding of the present disclosure, but the present disclosure may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present disclosure, rather than all of the embodiments.

[0022] The infrared hyperspectral imaging detector provided by the disclosed embodiments is based on infrared colloidal quantum dots. The CQD infrared detection unit formed from these infrared colloidal quantum dots can be directly coupled to a silicon-based readout circuit. A Fabry-Perot filter (FP filter) array can also be directly coupled above the CQD infrared detection unit (i.e., on the light-incoming side facing away from the readout circuit) to achieve pixel-level filtering. By setting different transmittance bands for different filters in the random filter array—for example, by designing a first type of FP filter with top and bottom distributed Bragg reflectors (DBRs) and a second type of FP filter with only a bottom DBR—combined with a differentiated optical cavity thickness design, spectral diversity can be achieved. By randomly arranging the FP filters and obtaining the transmittance of the FP filters for each pixel in the random filter array, the compressed information detected by the infrared hyperspectral detector is decompressed into hyperspectral information through random spatial-spectral encoding. The disclosed embodiments overcome the limitations of traditional infrared materials and traditional pixel-level filter methods, achieving high-resolution, real-time hyperspectral imaging.

[0023] For example, Figure 1 This is a schematic diagram of the structure of an infrared hyperspectral imaging detector provided by an embodiment of the present disclosure. Figure 1 , the infrared hyperspectral imaging detector 10 includes: a readout circuit 11, a colloidal quantum dot infrared detection unit and a random filter array 13. Among them, the readout circuit 11 has an array-arranged pixel circuit, that is, the readout circuit 11 is a planar array readout circuit. The colloidal quantum dot infrared detection unit is coupled to one side of the readout circuit 11; the colloidal quantum dot infrared detection unit is arranged in an array on one side of the readout circuit 11, forming an array 12 of colloidal quantum dot infrared detection units corresponding to the planar array readout circuit. The random filter array 13 is coupled to the side of the array 12 of the colloidal quantum dot infrared detection unit away from the readout circuit 11; the random filter array 13 includes filters arranged in an array (refer to Figure 3 or Figure 7 ), different filters have different light transmission bands, and the light transmission bands of the filters are within the detection wavelength range of the corresponding colloidal quantum dot infrared detection unit.

[0024] For example, Figure 7 A structure of a random filter array shown in FIG, wherein the random filter array includes a plurality of filters with different light transmission bands, Figure 7 A grid of a certain color represents a filter. Different filters have different light transmission bands. In other implementations, the filters in the random filter array may be arranged in other ways, which are not limited here.

[0025] In the infrared hyperspectral imaging detector 10 provided by the embodiment of the present disclosure, the colloidal quantum dot infrared detection unit can be directly coupled with the area array readout circuit to realize area array infrared imaging, thereby eliminating the need for scanning or encoding, and can achieve real-time imaging with high imaging efficiency and high image resolution. At the same time, by setting the detection unit as a colloidal quantum dot detection unit, the colloidal quantum dots can be directly coupled with the readout circuit without the need for a flip-chip bonding coupling method, which is low in cost. Moreover, there is no flip-chip solder base above the colloidal quantum dot infrared detection unit, and it can be directly coupled with the filter to achieve hyperspectral detection. In addition, by directly coupling the filter with the readout circuit coated with colloidal quantum dots, the filter can be selectively transparent, eliminating the need for spectroscopic scanning, simplifying the structure of the optical system and the imaging detector, and the hyperspectral image can be directly output with a fast imaging speed, which can achieve real-time imaging. In addition, a random filter array composed of filters is used as a coding mask, and efficient information compression is achieved through random spatial-spectral encoding, thereby achieving real-time and high-resolution hyperspectral imaging.

[0026] In some embodiments, Figure 1 The readout circuit 11 in the embodiment can be CMOS, TFT or CCD.

[0027] In some embodiments, Figure 2 This is a schematic diagram of the working principle of a filter in an infrared hyperspectral imaging detector provided by an embodiment of the present disclosure. Figure 3 This is a schematic diagram of the structure of a random filter array in an infrared hyperspectral imaging detector provided by an embodiment of the present disclosure. Figure 1 Based on the reference Figure 2 and Figure 3 The filters 130 in the random filter array 13 may include a first type of filter 1301 and a second type of filter 1302; along the direction of the readout circuit 11 pointing to the random filter array 13 ( Figure 2 and Figure 3 (from bottom to top in the figure), the first type of filter 1301 includes two distributed Bragg reflectors arranged opposite to each other and an optical cavity 133 located between the two distributed Bragg reflectors. Figure 2 and Figure 3 , two distributed Bragg reflectors are shown as a first reflector 131 and a second reflector 132; the second type of filter 1302 includes a distributed Bragg reflector (i.e., the first reflector 131) and an optical cavity 133; wherein, the thickness of the optical cavity 133 of different first type filters 1301 is different, and the thickness of the optical cavity 133 of different second type filters 1302 is different.

[0028] Two distributed Bragg reflectors (DBRs) are positioned opposite each other, each with two parallel, highly reflective surfaces. Filter 130 is located between the two reflectors, forming a Fabry-Perot filter (FP filter). Incident light is reflected multiple times between the two reflectors, forming multi-beam interference. When the phase difference between each round trip within the cavity is an integer multiple of 2π (i.e., the resonance condition is met), constructive interference occurs, resulting in maximum transmittance. By adjusting the thickness of the optical cavity, the wavelength band of light with maximum transmittance can be changed.

[0029] Furthermore, by making the optical cavity thickness of different first-type filters in the entire random filter array gradually change, and the optical cavity thickness of different second-type filters gradually change, that is, the optical cavity thickness of the filters in the random filter array is gradually changed, and a part of the number of filters only contain the bottom DBR (refer to Figure 3 ), which can make the spectral transmittance of different filters in the random filter array different, thereby achieving spectral diversity (reference Figure 6 In the preparation method, FP filters with different optical cavity thicknesses and containing only the bottom DBR are formed into a random filter array by photolithography and etching, which will be described in detail later.

[0030] In some embodiments, the size of the optical cavity is consistent with the size of the corresponding coupled pixel circuit, that is, the size is the same within the allowable error range, thereby realizing pixel-level setting of the filter and further realizing pixel-level filtering based on the random filter array.

[0031] It can be understood that the same size can mean having the same two-dimensional size in a plane parallel to the readout circuit. For example, if both are rectangles, they can have the same length and width; or if both are circles, they can have the same diameter. This is not limited here.

[0032] In some embodiments, the number of filters of the first type and the number of filters of the second type are the same, whereby the optical cavity thickness of the filters in the random filter array is graded, and half of the number of filters contain only the bottom DBR (refer to Figure 3 ), which can make the spectral transmittance of different filters in the random filter array different, thereby achieving spectral diversity.

[0033] In some embodiments, the colloidal quantum dot infrared detection unit may be a photoconductive detection unit.

[0034] For example, Figure 4 A schematic diagram of the structure of a single pixel in an infrared hyperspectral imaging detector provided in an embodiment of the present disclosure. Figure 1 Based on the reference Figure 4 The single pixel structure of the infrared hyperspectral imaging detector 10 may include a pixel circuit 110, a colloidal quantum dot infrared detection unit 120 and a filter 130; wherein the colloidal quantum dot infrared detection unit 120 includes a first electrode 121, a second electrode 122 and a colloidal quantum dot layer 123, the first electrode 121 and the second electrode 122 are arranged relative to each other in a plane parallel to the readout circuit, and the colloidal quantum dot layer 123 is located on the side of the first electrode 121 and the second electrode 122 away from the readout circuit, and is filled between the first electrode 121 and the second electrode 122.

[0035] In some embodiments, the colloidal quantum dot infrared detection unit may be a photovoltaic detection unit.

[0036] For example, Figure 5 This is a schematic diagram of another single pixel structure in the infrared hyperspectral imaging detector provided by the embodiment of the present disclosure. Figure 1 Based on the reference Figure 5 The single pixel structure of the infrared hyperspectral imaging detector 10 may include a pixel circuit 110, a colloidal quantum dot infrared detection unit 120 and a filter 130; wherein the colloidal quantum dot infrared detection unit 120 includes a direction along the readout circuit 11 pointing to the random filter array 13 ( Figure 4The third electrode 124, the first-type doped layer 125, the colloidal quantum dot layer 123, the second-type doped layer 127, and the fourth electrode 128 are stacked (from bottom to top in the figure). The first-type doped layer 125 and the second-type doped layer 127 are respectively one of an N-type doped layer and a P-type doped layer, and the two are different. Exemplarily, the first-type doped layer 125 is an N-type doped layer and the second-type doped layer 127 is a P-type doped layer; alternatively, the first-type doped layer 125 is a P-type doped layer and the second-type doped layer 127 is an N-type doped layer, but this is not limited here.

[0037] Below Figure 4 and Figure 5 Based on this, the optional materials for each layer in the colloidal quantum dot infrared detection unit 120 are exemplarily described.

[0038] In some embodiments, the colloidal quantum dot layer (i.e. Figure 4 The colloidal quantum dot layer 123 is shown, or Figure 5 The colloidal quantum dot layer 123 shown includes infrared colloidal quantum dots, and the material of the infrared colloidal quantum dots is one of lead sulfide (PbS), lead selenide (PbSe), lead telluride (PbTe), cadmium sulfide (CdS), cadmium selenide (CdSe), mercury telluride (HgTe), mercury selenide (HgSe), mercury sulfide (HgS), silver telluride (Ag2Te), silver sulfide (Ag2S) and silver selenide (Ag2Se).

[0039] In some embodiments, Figure 4 In the embodiment, the first electrode 121 and the second electrode 122 may be metal electrodes; Figure 5 In the embodiment, the third electrode 124 is a metal electrode or a transparent electrode, and the fourth electrode 128 is a transparent electrode.

[0040] The material of the metal electrode may be one of platinum, gold, silver, copper, aluminum and chromium, and the material of the transparent electrode may be indium tin oxide (ITO) or fluorine-doped tin dioxide (FTO).

[0041] In some embodiments, Figure 5On the basis of the N-type doping layer, the materials of the N-type doping layer include bismuth selenide (Bi2Se3), bismuth sulfide (Bi2S3), bismuth telluride (Bi2Te3), zinc oxide (ZnO), cadmium selenide (CdSe), titanium dioxide (TiO2), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), methyl butyrate (PCBM) and one of the N-type quantum dots with the same material as the colloidal quantum dot layer; the materials of the P-type doping layer include silver telluride (Ag2Te), poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), poly 3-hexylthiophene (P3HT), 2,2',7,7'-tetrakis [N,N-di(4-methoxyphenyl)amino] -9,9'-spirobifluorene (spiro-OMeTAD), polytriarylamine (PTAA), nickel oxide (NiO x )、ZnTe)、C 60 and one of the P-type quantum dots that are the same material as the colloidal quantum dot layer.

[0042] In other embodiments, each layer in the colloidal quantum dot infrared detection unit 120 may also be made of other materials known to those skilled in the art, which is not limited here.

[0043] The imaging principle and effect of the infrared hyperspectral imaging detector provided by the embodiments of the present disclosure are exemplarily described below.

[0044] Specifically, the random filter array is directly coupled to the side of the array of colloidal quantum dot infrared detection units away from the array readout circuit, so that a filter with a specific light transmission band is directly integrated on each pixel. Figure 7 Different colors represent filters with different transmittance bands. After forming a randomly arranged FP filter array, before coupling the random filter array to the detector, the transmittance of each filter in the random filter array in each band is measured according to the response band of colloidal quantum dots detection.

[0045] For example, the response band of the detector is 1000nm~2500nm (actually, the response band varies from 800-15000nm depending on the type of colloidal quantum dots). For the interval ( can be 10-100nm), respectively measure the transmittance of the filter array , It represents the array scale of the readout circuit (e.g., 128×128, 320×256, 640×512, 1280×1024 pixel arrays). After measuring the transmittance, the random filter array is coupled to the area array readout circuit coupled with the colloidal quantum dot infrared detection unit by gluing or welding.

[0046] When the information of the imaged object is captured by the detector, the information of the imaged object contains spatial information and spectral information , spatial information and spectral information can be jointly represented as a three-dimensional data matrix (such as 640×512×20 band), since each pixel on the detector The spectral transmittance of the filter on are all different (reference Figure 6 ), so the light of different wavelengths in each pixel will be summed up, and finally form a monochrome compressed image , which can be specifically expressed as:

[0047] in, is the number of bands, which must be at least 4; then an iterative algorithm (such as gradient descent, Newton's method, conjugate gradient method, Jacobi iteration method, Gauss-Seidel iteration method, ISTA, FISTA, TwIST) is used to solve , to achieve hyperspectral imaging, the process diagram is shown in Figure 7 .

[0048] The embodiments of the present disclosure also provide an imaging method for an infrared hyperspectral imaging detector. The imaging method is performed based on any one of the infrared hyperspectral imaging detectors provided in the above embodiments, and can perform real-time imaging with high resolution and richer imaging details.

[0049] The embodiments of the present disclosure also provide a method for preparing an infrared hyperspectral imaging detector, which is used to form any of the infrared hyperspectral imaging detectors provided in the above embodiments.

[0050] For example, Figure 8 A schematic diagram of a process for preparing an infrared hyperspectral imaging detector according to an embodiment of the present disclosure. Figure 8 The preparation method of the infrared hyperspectral imaging detector may include the following steps.

[0051] S21. Provide and clean a readout circuit.

[0052] Among them, the readout circuit has an array-arranged pixel circuit; the readout circuit can be cleaned with cleaning solutions such as acetone, isopropyl alcohol, alcohol, deionized water, etc. to remove dirt and impurities on the surface of the readout circuit, which is beneficial to improve the preparation quality of the colloidal quantum dot infrared detection unit, thereby improving the overall performance of the infrared hyperspectral imaging detector.

[0053] S22. Prepare a colloidal quantum dot infrared detection unit on one side of the readout circuit.

[0054] Among them, the colloidal quantum dot infrared detection units are arranged in an array on one side of the readout circuit.

[0055] In some embodiments, the colloidal quantum dot infrared detection unit is a photoconductive infrared detection unit. The preparation of the colloidal quantum dot infrared detection unit may specifically include: A preset electrode layer is formed on one side of the readout circuit, wherein the preset electrode layer is a whole layer of electrodes; Performing patterning on the preset electrode layer to form a first electrode and a second electrode, wherein the first electrode and the second electrode are arranged opposite to each other in a plane parallel to the plane where the readout circuit is located; On the side of the first electrode and the second electrode away from the readout circuit, a colloidal quantum dot layer is formed by spin coating, drop coating, spray coating, scraping or evaporation, and the colloidal quantum dot layer is also filled between the first electrode and the second electrode.

[0056] In some embodiments, the colloidal quantum dot infrared detection unit is a photovoltaic infrared detection unit. The preparation of the colloidal quantum dot infrared detection unit may specifically include: forming a third electrode on one side of the readout circuit; On a side of the third electrode facing away from the readout circuit, a first type doping layer is formed by a film forming method such as drop coating, spin coating, spray coating, blade coating or evaporation; forming a colloidal quantum dot layer on a side of the first type doped layer facing away from the third electrode by spin coating, drop coating, spray coating, blade coating or evaporation; On the side of the colloidal quantum dot layer facing away from the first type doping layer, a second type doping layer is formed by a film forming method such as drop coating, spin coating, spray coating, blade coating or evaporation; On the side of the second type doping layer away from the colloidal quantum dot layer, a fourth electrode is formed by adopting a film forming method such as thermal evaporation, magnetron sputtering, or atomic layer deposition.

[0057] The first electrode and the second electrode may be metal electrodes, the third electrode may be a metal electrode or a transparent electrode, and the fourth electrode may be a transparent electrode.

[0058] In some embodiments, preparing a metal electrode may specifically include: forming a whole layer of electrodes on one side of a readout circuit, and then modifying the whole layer of electrodes using a photolithography process selected from ultraviolet lithography, laser direct writing, and electron beam exposure (one of dry etching, wet etching, and stripping) to obtain a patterned electrode layer, wherein the thickness of the electrode is 5 nanometers to 100 nanometers.

[0059] For the photoconductive infrared detection unit, infrared colloidal quantum dots are prepared on the electrode layer by one of the following film-forming methods: spin coating, drop coating, spray coating, scraping coating and evaporation. The thickness of the infrared colloidal quantum dots after film formation is 100 nanometers to 1000 nanometers.

[0060] For the photovoltaic infrared detection unit, after the electrode layer is formed, the material of the N-type doping layer is formed on the electrode layer by one of the film-forming methods selected from drop coating, spin coating, spray coating, scraping and evaporation, and the thickness of the N-type doping layer is 50 nanometers to 200 nanometers; then, the infrared colloidal quantum dots (i.e., intrinsic colloidal quantum dots) are formed on the N-type doping layer by one of the film-forming methods selected from spin coating, drop coating, spray coating, scraping and evaporation, and the thickness of the colloidal quantum dot layer is 300 nanometers to 1000 nanometers; then, the material of the P-type doping layer is formed on the colloidal quantum dot layer by one of the film-forming methods selected from drop coating, spin coating, spray coating, scraping and evaporation, and the thickness of the P-type doping layer is 50 nanometers to 200 nanometers; then, the material of the fourth electrode (i.e., the transparent electrode) is formed on the P-type doping layer by thermal evaporation, magnetron sputtering or atomic layer deposition, and the thickness of the fourth electrode is 5 nanometers to 100 nanometers.

[0061] S23. Couple a random filter array to a side of the colloidal quantum dot infrared detection unit that is away from the readout circuit.

[0062] The random filter array includes filters arranged in an array, and different filters have different light transmission bands, and the light transmission bands of the filters are within the detection wavelength range of the corresponding colloidal quantum dot infrared detection unit.

[0063] In some embodiments, coupling a random filter array comprises: The random filter array is coupled by glue curing or welding.

[0064] In some embodiments, the steps of preparing the random filter array may specifically include: In the first step, silicon (Si) and silicon dioxide (SiO2) are alternately deposited on a cleaned sapphire substrate by chemical vapor deposition (CVD), physical vapor deposition (PVD) or atomic layer deposition to form the first distributed Bragg reflector with a total thickness of 200 nanometers to 2000 nanometers.

[0065] In the second step, 1 to 2 microns of silicon dioxide (SiO2) are deposited as an optical cavity by chemical vapor deposition (CVD), physical vapor deposition (PVD), or atomic layer deposition (ALD). The thickness of the optical cavity on the entire surface is varied through grayscale masking or multiple exposures (including UV lithography, laser direct writing, and electron beam exposure) and etching processes (dry or wet etching), forming an array of multiple optical cavities with different thicknesses. The size of each optical cavity must be consistent with the pixel size of the corresponding coupled readout circuit (for example, if the pixel size in the coupled readout circuit is 15μm×15μm, the size of the corresponding single optical cavity should also be 15μm×15μm), thus achieving pixel-level filtering.

[0066] In the third step, silicon (Si) and silicon dioxide (SiO2) are alternately deposited on a portion (e.g., half) of the optical cavity array by chemical vapor deposition (CVD), physical vapor deposition (PVD), or atomic layer deposition (ALD) to form a second distributed Bragg reflector with a total thickness of 200 nm to 2000 nm.

[0067] The fourth step is to use photolithography (including ultraviolet lithography, laser direct writing and electron beam exposure) to make the size of the filter consistent with the pixel size of the corresponding coupled readout circuit (for example, if the pixel size of the coupled readout circuit is 15μm×15μm, the size of the corresponding single optical cavity should also be 15μm×15μm); to form an independent filter unit (the scale of the filter array should be consistent with the scale of the readout circuit to be coupled).

[0068] In the preparation method of the infrared hyperspectral imaging detector provided by the embodiment of the present disclosure, a colloidal quantum dot layer can be formed by a film-forming method selected from spin coating, drip coating, spray coating, scraping coating and evaporation, so that the array of colloidal quantum dot infrared detection units is directly coupled to the area array readout circuit, and the detected light signal is converted into an electrical signal and output. Among them, infrared colloidal quantum dots are used as photosensitive materials to prepare colloidal quantum dot infrared detection units. By changing the reaction temperature, reaction time, reaction material ratio and other parameters during the synthesis of infrared colloidal quantum dots, the wavelength range of the infrared colloidal quantum dots response can be accurately adjusted to widen the detection band of the detector. Exemplarily, the size of the infrared colloidal quantum dots can be 2 nanometers to 8 nanometers, corresponding to a wavelength response range of 1000 nanometers to 3000 nanometers. At the same time, the synthesis process of infrared colloidal quantum dots is simple, and the liquid material can be converted into a solid functional film through a low-cost liquid phase processing process, without the need for expensive flip-chip bonding, molecular beam epitaxy and other processes, which greatly reduces the material processing cost and reduces the detector cost.

[0069] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a..." does not exclude the presence of other identical elements in the process, method, article or device that includes the element.

[0070] The foregoing description is intended only to provide specific embodiments of the present disclosure, intended to enable those skilled in the art to understand and implement the present disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure is not intended to be limited to the embodiments described herein, but rather to be construed in the broadest manner consistent with the principles and novel features disclosed herein.

Claims

1. An infrared hyperspectral imaging detector, characterized in that: include: A readout circuit having pixel circuits arranged in an array; A colloidal quantum dot infrared detection unit is coupled to one side of the readout circuit; the colloidal quantum dot infrared detection units are arranged in an array on one side of the readout circuit; A random filter array is coupled to the side of the colloidal quantum dot infrared detection unit away from the readout circuit; the random filter array includes filters arranged in an array, different filters have different light transmission bands, and the light transmission bands of the filters are within the detection wavelength range of the corresponding colloidal quantum dot infrared detection unit.

2. The infrared hyperspectral imaging detector according to claim 1, characterized in that: The optical filters include a first type of optical filter and a second type of optical filter; Along the direction of the readout circuit pointing to the random filter array, the first type of filter includes two distributed Bragg reflectors arranged opposite to each other and an optical cavity located between the two distributed Bragg reflectors, and the second type of filter includes one distributed Bragg reflector and an optical cavity; The thickness of the optical cavity of different first-type filters is different, and the thickness of the optical cavity of different second-type filters is different.

3. The infrared hyperspectral imaging detector according to claim 2, characterized in that: The size of the optical cavity is consistent with the size of the corresponding coupled pixel circuit.

4. The infrared hyperspectral imaging detector according to claim 2, characterized in that: The number of the first type of filters is the same as the number of the second type of filters.

5. The infrared hyperspectral imaging detector according to claim 1, characterized in that: The colloidal quantum dot infrared detection unit includes a first electrode, a second electrode and a colloidal quantum dot layer, wherein the first electrode and the second electrode are arranged opposite to each other in a plane parallel to the readout circuit, and the colloidal quantum dot layer is located on a side of the first electrode and the second electrode away from the readout circuit, and is filled between the first electrode and the second electrode; or, The colloidal quantum dot infrared detection unit includes a third electrode, a first type doping layer, a colloidal quantum dot layer, a second type doping layer and a fourth electrode stacked along the direction of the readout circuit pointing to the random filter array, the first type doping layer and the second type doping layer are respectively one of an N-type doping layer and a P-type doping layer, and the two are different.

6. The infrared hyperspectral imaging detector according to claim 5, characterized in that: The material of the colloidal quantum dot layer includes one of lead sulfide, lead selenide, lead telluride, cadmium sulfide, cadmium selenide, mercury telluride, mercury selenide, mercury sulfide, silver telluride, silver sulfide and silver selenide; The first electrode and the second electrode are metal electrodes, the third electrode is a metal electrode or a transparent electrode, and the fourth electrode is a transparent electrode; wherein the material of the metal electrode includes one of platinum, gold, silver, copper, aluminum, and chromium, and the material of the transparent electrode includes one of indium tin oxide and fluorine-doped tin dioxide; The material of the N-type doping layer includes one of bismuth selenide, bismuth sulfide, bismuth telluride, zinc oxide, cadmium selenide, titanium dioxide, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, methyl butyrate, and N-type quantum dots that are the same as the colloidal quantum dot layer material; The material of the P-type doping layer includes silver telluride, poly (3,4-ethylenedioxythiophene) polystyrene sulfonate, poly 3-hexylthiophene, 2,2',7,7'-tetrakis [N,N-bis (4-methoxyphenyl) amino] -9,9'-spirobifluorene, polytriarylamine, nickel oxide, zinc telluride, C 60 and one of the P-type quantum dots that are the same material as the colloidal quantum dot layer.

7. A method for preparing an infrared hyperspectral imaging detector, characterized in that: Used to form the infrared hyperspectral imaging detector according to any one of claims 1 to 6; The preparation method of the infrared hyperspectral imaging detector comprises: Providing and cleaning a readout circuit; the readout circuit has pixel circuits arranged in an array; A colloidal quantum dot infrared detection unit is prepared on one side of the readout circuit; the colloidal quantum dot infrared detection unit is arranged in an array on one side of the readout circuit; A random filter array is coupled to the side of the colloidal quantum dot infrared detection unit facing away from the readout circuit; the random filter array includes filters arranged in an array, different filters have different light transmission bands, and the light transmission bands of the filters are within the detection wavelength range of the corresponding colloidal quantum dot infrared detection unit.

8. The method for preparing an infrared hyperspectral imaging detector according to claim 7, wherein: The method for preparing a colloidal quantum dot infrared detection unit comprises: forming a preset electrode layer on one side of the readout circuit; performing patterning on the preset electrode layer to form a first electrode and a second electrode, wherein the first electrode and the second electrode are arranged opposite to each other in a plane parallel to the plane where the readout circuit is located; forming a colloidal quantum dot layer on a side of the first electrode and the second electrode facing away from the readout circuit by spin coating, drop coating, spray coating, blade coating or evaporation, wherein the colloidal quantum dot layer is also filled between the first electrode and the second electrode; or, The method for preparing a colloidal quantum dot infrared detection unit comprises: forming a third electrode on one side of the readout circuit; forming a first type doping layer on a side of the third electrode facing away from the readout circuit by using a film forming method such as drop coating, spin coating, spray coating, blade coating or evaporation; forming a colloidal quantum dot layer on a side of the first type doped layer facing away from the third electrode by spin coating, drop coating, spray coating, blade coating or evaporation; On a side of the colloidal quantum dot layer facing away from the first type doping layer, forming a second type doping layer by using a film forming method such as drop coating, spin coating, spray coating, blade coating or evaporation; On the side of the second-type doping layer away from the colloidal quantum dot layer, a fourth electrode is formed by using a film forming method such as thermal evaporation, magnetron sputtering, or atomic layer deposition.

9. The method for preparing an infrared hyperspectral imaging detector according to claim 7, wherein: The random filter array is coupled to a side of the colloidal quantum dot infrared detection unit away from the readout circuit, comprising: The random filter array is coupled to a side of the colloidal quantum dot infrared detection unit that is away from the readout circuit by means of glue curing or welding.

10. An imaging method for an infrared hyperspectral imaging detector, characterized in that: Executed based on the infrared hyperspectral imaging detector according to any one of claims 1 to 6.

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