Infrared focal plane detector, infrared focal plane detection system, and preparation method

Abstract

The present disclosure relates to an infrared focal plane detector, an infrared focal plane detection system, and a preparation method. The infrared focal plane detector comprises a flexible curved substrate and a quantum dot detection structure, wherein the quantum dot detection structure is located on the side of a light-incident surface of the flexible curved substrate, and is configured to respond to an external infrared ambient light signal and output to the flexible curved substrate an electrical signal to a readout circuit of the flexible curved substrate. In this way, by means of disposing the quantum dot detection structure on the side of the light-incident surface of the flexible curved substrate, effective coupling between the quantum dot detection structure and the flexible curved substrate is ensured, thereby helping to realize large-scale preparation and application of the infrared focal plane detector.

Description

Infrared focal plane detector, system and fabrication method

[0001] Cross-references to related applications

[0002] This disclosure claims priority to Chinese Patent Application No. 202411003370.0, filed on July 25, 2024, entitled "Infrared Focal Plane Detector, System and Preparation Method", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to the field of infrared detection technology, and in particular to an infrared focal plane detector, system, and preparation method. Background Technology

[0004] In the field of infrared imaging, infrared detectors have evolved from single units to multi-unit units, and then from multi-unit units to focal plane arrays, resulting in various types of infrared detectors, such as infrared detectors that integrate flexible curved substrates with traditional flexible sensing functional units. These detectors offer significant potential and development space for the arraying of sensors on flexible curved substrates, and have become a focus of attention in the field of infrared imaging.

[0005] However, the crystal epitaxial materials used in current infrared detectors are usually rigid materials that are not easy to bend or compress, and their lattice does not match the flexible curved substrate. Therefore, it is difficult to grow them on the flexible curved substrate, which limits the large-scale fabrication and application of flexible infrared focal plane detectors. Summary of the Invention

[0006] To solve the above-mentioned technical problems, or at least partially solve them, this disclosure provides an infrared focal plane detector, system, and preparation method.

[0007] This disclosure provides an infrared focal plane detector, comprising: a flexible curved substrate and a quantum dot detection structure; the quantum dot detection structure is located on the light-incident surface side of the flexible curved substrate; the quantum dot detection structure is used to output an electrical signal to the readout circuit of the flexible curved substrate in response to an external infrared ambient light signal.

[0008] In some embodiments, the quantum dot detection structure includes: a plurality of first electrodes, wherein the plurality of first electrodes are spaced apart in the plane of the flexible curved substrate, and the first electrodes are electrically connected to the readout circuit; a quantum dot infrared absorption layer is located on the side of the first electrodes away from the flexible curved substrate, and fills the gap between the first electrodes; and a second electrode is disposed on the side of the quantum dot infrared absorption layer away from the flexible curved substrate.

[0009] In some embodiments, the quantum dot detection structure includes: a plurality of first electrodes, wherein the plurality of first electrodes are spaced apart in the plane of the flexible curved substrate, and the first electrodes are electrically connected to the readout circuit; an N-type quantum dot layer located on the side of the first electrodes away from the flexible curved substrate, and filling the gaps between the first electrodes; a quantum dot infrared absorption layer located on the side of the N-type quantum dot layer away from the first electrodes; a P-type quantum dot layer located on the side of the quantum dot infrared absorption layer away from the N-type quantum dot layer; and a second electrode located on the side of the P-type quantum dot layer away from the quantum dot infrared absorption layer.

[0010] In some embodiments, the thickness of the N-type quantum dot layer is 5 nm to 10 nm; the thickness of the quantum dot infrared absorption layer is 200 to 1000 nm; and the thickness of the P-type quantum dot layer is 5 nm to 10 nm.

[0011] In some embodiments, the N-type quantum dot layer comprises at least one of bismuth selenide, bismuth sulfide, bismuth telluride, zinc oxide, and cadmium selenide; the P-type quantum dot layer comprises at least one of poly(3-hexylthiophene), poly(3,4-ethylenedioxythiophene)polystyrene sulfonate, 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene, and polytriarylamine.

[0012] In some embodiments, the quantum dot infrared absorption layer comprises colloidal quantum dots, which include at least one of lead sulfide, lead selenide, mercuric telluride, mercuric selenide, cadmium sulfide, cadmium telluride, cadmium selenide, silver sulfide, silver telluride, silver selenide, and mercuric cadmium telluride.

[0013] In some embodiments, the radius of curvature of the flexible curved substrate is greater than or equal to 3 mm.

[0014] This disclosure also provides an infrared focal plane detector system, including an imaging lens and any of the above-mentioned infrared focal plane detectors; wherein the imaging lens is located on the light-incident surface side of the infrared focal plane detector.

[0015] This disclosure also provides a method for fabricating an infrared focal plane detector, the method comprising: providing a flexible curved substrate; forming a quantum dot detection structure on one side of the light-incident surface of the flexible curved substrate; wherein the quantum dot detection structure is used to output an electrical signal to the readout circuit of the flexible curved substrate in response to an external infrared ambient light signal.

[0016] In some embodiments, forming a quantum dot detection structure on the light-incident surface side of the flexible curved substrate includes: stacking a quantum dot infrared absorption layer of the quantum dot detection structure on the light-incident surface side of the flexible curved substrate using any one of spin coating, spray coating, and drop coating.

[0017] The technical solution provided in this disclosure has the following advantages compared with the prior art:

[0018] The infrared focal plane detector provided in this embodiment ensures effective coupling between the quantum dot detection structure and the flexible curved substrate by placing the quantum dot detection structure on the light-incident surface of the flexible curved substrate, thereby facilitating the large-scale fabrication and application of the infrared focal plane detector. Attached Figure Description

[0019] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0020] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 is a schematic diagram of the structure of an infrared focal plane detector provided in an embodiment of this disclosure;

[0022] Figure 2 is a schematic diagram of another infrared focal plane detector provided in an embodiment of this disclosure;

[0023] Figure 3 is a schematic diagram of the structure of another infrared focal plane detector provided in an embodiment of this disclosure;

[0024] Figure 4 is a schematic diagram of the spectral absorption of an infrared focal plane detector provided in an embodiment of this disclosure;

[0025] Figure 5 is a schematic diagram of an infrared focal plane detection system provided in an embodiment of this disclosure;

[0026] Figure 6 is a schematic flowchart of a method for fabricating an infrared focal plane detector according to an embodiment of this disclosure.

[0027] Among them, 100 is an infrared focal plane detector; 110 is a flexible curved substrate; 120 is a quantum dot detection structure; 121 is a first electrode; 122 is a quantum dot infrared absorption layer; 123 is a second electrode; 124 is an N-type quantum dot layer; 125 is a P-type quantum dot layer; and 130 is an imaging lens. Detailed Implementation

[0028] To better understand the above-mentioned objectives, features, and advantages of this disclosure, the solutions disclosed herein will be further described below. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0029] Numerous specific details are set forth in the following description in order to provide a full understanding of this disclosure, but this disclosure may also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only some, and not all, of the embodiments of this disclosure.

[0030] In the field of infrared detection technology, infrared detectors are used to convert external infrared ambient light signals (also known as infrared radiation signals) into electrical signal outputs. They have evolved from single-element to multi-element, and then from multi-element to focal plane, realizing a leap from point source detection to target thermal imaging. This has led to the formation of a wide variety of infrared detectors, providing ample choice for the system applications of infrared detectors.

[0031] In infrared detectors achieve high-resolution imaging through multi-lens systems to correct optical aberrations and flatten the projected image on a plane, significantly increasing system complexity, size, and cost. Attempting to cover the real image with a single lens results in significant spatial mismatch in focal point due to spherical aberration. In contrast, the human eye, despite having only a simple single-lens imaging system, provides high-resolution imaging with adjustable zoom capabilities. This superior performance stems from the curved retina, which corrects spherical aberration by matching the curvature of the lens's focal plane. Therefore, inspired by the unique advantages of the biological eye—its Petzval-matched curvature, wide field of view, and simplified lens system—electronic eye systems have received increasing attention and research. However, directly fabricating infrared detectors on flexible surfaces is complex, expensive, and limited in available instruments.

[0032] With the development of semiconductor manufacturing technology, a set of miniature photodetectors separated by electrically interconnected metal traces can be fabricated based on mature semiconductor manufacturing techniques. Initially, these detectors were fabricated on a flexible substrate with a planar structure, and then the planar array was bent or folded to shape a hemispherical structure. Leveraging the manufacturing advantages of flexible arrays, the hemispherical flexible substrate can be integrated with traditional flexible sensing functional units, thereby improving the sensitivity and dimensionality of the infrared detector. This flexible substrate-based sensing technology offers significant development potential and room for improvement in realizing the arraying of sensing functional units on flexible substrates.

[0033] However, infrared detectors are primarily grown from epitaxial materials on planar substrates. These planar substrates can be rigid and brittle crystalline materials, such as cadmium zinc telluride (CdZeTe), gallium arsenide (GaAs), indium arsenide (InAs), and indium phosphide (InP), which lack bending properties. Commonly used epitaxial materials include rigid gallium arsenide (InGaAs), indium antimony (InSb), and mercury cadmium telluride (MCT). Typically, epitaxial materials require a lattice-matched substrate for growth. Because epitaxial materials are not easily bent or compressed, and their lattices do not match flexible curved substrates, they are difficult to grow on flexible curved substrates.

[0034] Currently, existing flexible infrared focal plane detectors use flip-chip bonding to bond crystal epitaxial materials to flexible curved substrates. This method has a long preparation cycle, slow production rate, high material processing cost, and low bonding success rate. In fact, incomplete soldering may occur during the welding process, which reduces the detection efficiency of the infrared detector and limits the large-scale preparation and application of flexible infrared focal plane detectors.

[0035] To address at least one of the aforementioned problems, this disclosure provides an infrared focal plane detector, system, and fabrication method. Specifically, for the infrared focal plane detector, since colloidal quantum dots (CQDs) are infrared materials with scalable synthesis, mechanical flexibility, and broad-spectrum tunability, by placing the quantum dot detection structure on the light-incident side of a flexible curved substrate, effective coupling between the quantum dot detection structure and the flexible curved substrate can be ensured without welding. This facilitates the large-scale fabrication and application of infrared focal plane detectors, such as in chemical detection, wafer inspection, object monitoring, and national defense security.

[0036] The infrared focal plane detector, system, and preparation method provided in the embodiments of this disclosure will be described exemplarily below with reference to the accompanying drawings.

[0037] Figure 1 is a schematic diagram of an infrared focal plane detector provided in an embodiment of this disclosure. Referring to Figure 1, the infrared focal plane detector includes: a flexible curved substrate 110 and a quantum dot detection structure 120; the quantum dot detection structure 120 is located on the light-incident surface side of the flexible curved substrate 110; the quantum dot detection structure 120 is used to output an electrical signal to the readout circuit of the flexible curved substrate 110 in response to an external infrared ambient light signal.

[0038] In some embodiments, the flexible curved substrate 110 is a silicon-based readout circuit substrate for carrying the quantum dot detection structure 120. Exemplarily, the flexible curved substrate 110 may be made of polydimethylsiloxane, polyimide, or other materials, which are not limited herein.

[0039] In some embodiments, the quantum dot detection structure 120 is composed of quantum dot materials. Specifically, due to the advantages of quantum dot materials such as scalable synthesis, mechanical flexibility, and broad-spectrum tunability, the quantum dot detection structure 120 can be directly coupled to the flexible curved substrate 110, overcoming the problem that crystal epitaxial materials are difficult to grow on the flexible curved substrate 110. Moreover, it eliminates the need for the flip-chip bonding method required in the fabrication of existing infrared detectors, thereby reducing the fabrication cost of flexible infrared focal plane detectors and improving the yield, which is conducive to the large-scale fabrication and application of flexible infrared focal plane detectors.

[0040] Specifically, when ambient infrared light is incident on the infrared focal plane detector, the quantum dot detection structure 120 will perform a photoelectric response based on the ambient infrared light signal, that is, convert the ambient infrared light signal into an electrical signal. The electrical signal is then transmitted to the flexible curved substrate 110, and the (signal) readout circuit in the flexible curved substrate 110 converts the electrical signal into a digital signal and reads it out, so that other related circuits can process the digital signal for infrared imaging.

[0041] The infrared focal plane detector provided in this embodiment includes: a flexible curved substrate 110 and a quantum dot detection structure 120; the quantum dot detection structure 120 is located on the light-incident surface side of the flexible curved substrate 110; the quantum dot detection structure 120 is used to output an electrical signal to the readout circuit of the flexible curved substrate 110 in response to an external infrared ambient light signal. Thus, by placing the quantum dot detection structure 120 on the light-incident surface side of the flexible curved substrate 110, effective coupling between the quantum dot detection structure 120 and the flexible curved substrate 110 is ensured, thereby facilitating the large-scale fabrication and application of the infrared focal plane detector.

[0042] In some embodiments, FIG2 is a schematic diagram of another infrared focal plane detector provided in this disclosure. Based on FIG1 and referring to FIG2, the quantum dot detection structure 120 includes: a plurality of first electrodes 121, which are spaced apart in the plane of the flexible curved substrate 110 and are electrically connected to the readout circuit; a quantum dot infrared absorption layer 122, located on the side of the first electrodes 121 away from the flexible curved substrate 110, and filling the gap between the first electrodes 121; and a second electrode 123, disposed on the side of the quantum dot infrared absorption layer 122 away from the flexible curved substrate 110.

[0043] For example, taking the orientation and structure shown in Figure 2 as an example, on the side of the flexible curved substrate 110 that bends upward, a plurality of first electrodes 121 are spaced apart in the upper plane of the flexible curved substrate 110. A quantum dot infrared absorption layer 122 fills the gaps between the first electrodes 121 and covers the plurality of first electrodes 121. A second electrode 123 is located above the quantum dot infrared absorption layer 122. In this way, a light-guiding infrared focal plane detector is formed as a whole, which has a simple structure and reduces the fabrication complexity of the infrared focal plane detector.

[0044] In some embodiments, the first electrode 121 is the bottom electrode of the quantum dot detection structure 120, used to collect electrical signals (commonly known as electrons) generated by photoelectric response. Exemplarily, the first electrode 121 may be one or more of indium tin oxide (ITO), fluorine-doped zinc oxide (FTO), gold, silver, copper, aluminum, and chromium. In some embodiments, the first electrode 121 may be stacked to a predetermined thickness using physical vapor deposition (PVD) methods such as thermal evaporation and magnetron sputtering, or it may be stacked to a predetermined thickness using chemical vapor deposition (CVD). In some embodiments, patterned, arrayed first electrodes 121 may be fabricated using photolithography masking processes, such as photolithography followed by etching, or photolithography followed by stripping. In some embodiments, other electrode materials known to those skilled in the art may also be used to fabricate the first electrode 121, and are not limited thereto.

[0045] In some embodiments, the second electrode 123 is the top electrode of the quantum dot detector structure 120, used to collect holes generated by photoelectric response. Exemplarily, the second electrode 123 can be any one of gold, silver, copper, and aluminum. The second electrode 123 can be prepared by physical vapor deposition (PVD) such as thermal evaporation, electron beam evaporation, or magnetron sputtering, or by chemical vapor deposition (CVD). As long as the material used to prepare the top electrode does not affect its light transmittance and allows for the transmission of ambient infrared light, the material used to prepare the top electrode is not limited.

[0046] For example, the thickness of the first electrode 121 can be 5 nm to 200 nm, and the thickness of the second electrode 123 can be 5 nm to 50 nm, which is not limited here.

[0047] In some embodiments, the quantum dot infrared absorption layer 122 is a quantum dot layer for photoelectric response, i.e., an intrinsic quantum dot layer. Specifically, after ambient infrared light passes through the second electrode 123, the quantum dot infrared absorption layer 122 can generate photogenerated electron-hole pairs; then, the electrons are transported to the first electrode 121, and the holes are transported to the second electrode 123. Since the first electrode 121 is electrically connected to the readout circuit of the flexible curved substrate 110, the electrons can be transported to the readout circuit via the first electrode 121, and the readout circuit performs related processing on the electrons (i.e., electrical signals).

[0048] Thus, by arranging multiple first electrodes 121 at intervals within the plane of the flexible curved substrate, the effective contact area between the quantum dot infrared absorption layer 122 and the flexible curved substrate 110 is increased, thereby ensuring good coupling between the quantum dot infrared absorption layer 122 and the flexible curved substrate 110. Simultaneously, the first electrodes 121 can also be connected one-to-one with the pixel electrodes in the flexible curved substrate 110, facilitating the acquisition of multiple independent electrical signals by the flexible curved substrate 110. The spacing between adjacent first electrodes 121 can be set according to the fabrication requirements of the infrared focal plane detector, and is not limited thereto.

[0049] In some embodiments, FIG3 is a schematic diagram of another infrared focal plane detector provided in this disclosure. Based on FIG1 and referring to FIG3, the quantum dot detection structure 120 includes: a plurality of first electrodes 121, which are spaced apart in the plane of the flexible curved substrate 110 and are electrically connected to the readout circuit; an N-type quantum dot layer 124, located on the side of the first electrodes 121 away from the flexible curved substrate 110, and filling the gaps between the first electrodes 121; a quantum dot infrared absorption layer 122, located on the side of the N-type quantum dot layer 124 away from the first electrodes 121; a P-type quantum dot layer 125, located on the side of the quantum dot infrared absorption layer 122 away from the N-type quantum dot layer 124; and a second electrode 123, located on the side of the P-type quantum dot layer 125 away from the quantum dot infrared absorption layer 122.

[0050] For example, taking the orientation and structure shown in Figure 3 as an example, on the side of the flexible curved substrate 110 that bends upward, a plurality of first electrodes 121 are spaced apart in the upper plane of the flexible curved substrate 110. An N-type quantum dot layer 124 fills the gaps between the first electrodes 121 and covers the plurality of first electrodes 121. A quantum dot infrared absorption layer 122, a P-type quantum dot layer 125, and a second electrode 123 are sequentially stacked on top of the N-type quantum dot layer 124. In this way, a photovoltaic infrared focal plane detector is formed as a whole.

[0051] Specifically, since the N-type quantum dot layer 124 and the P-type quantum dot layer 125 are located on opposite sides of the quantum dot infrared absorption layer 122, a PN junction can be formed between them. Based on this, when ambient infrared light passes through the second electrode 123, the electrons and holes generated in the quantum dot infrared absorption layer 122 diffuse unevenly, thus creating a built-in potential inside the photovoltaic infrared focal plane detector. Under the influence of this built-in potential, electron-hole pairs can dissociate into free electrons and holes. Holes are transported to the second electrode 123 via the P-type quantum dot layer 125, and electrons are transported to the first electrode 121 via the N-type quantum dot layer 124.

[0052] In some embodiments, based on Figures 2 and 3, the infrared focal plane detector further includes an external power supply (not shown in the figures). The external power supply is connected to the second electrode 123 and the first electrode 121, respectively, and is used to apply an operating voltage to the infrared focal plane detector. It should be noted that by applying operating voltages to the photoconductive infrared focal plane detector and the photovoltaic infrared focal plane detector, respectively, the electrical signals (i.e., electrons) generated by the photoelectric response can be driven to move rapidly to the flexible curved substrate 110, forming a directional current, so that the electrical signals in the current can be collected and processed in a timely manner.

[0053] In addition, when an external power source applies a working voltage to the photovoltaic infrared focal plane detector, its built-in potential can be further enhanced, which increases the speed at which electron-hole pairs dissociate into free electrons and holes, as well as the transmission efficiency of electrons and holes. This leads to an increase in current saturation. Compared with the photoconductive infrared focal plane detector, the photovoltaic infrared focal plane detector has a better signal-to-noise ratio, ensuring good detection performance.

[0054] In some embodiments, based on Figures 2 and 3, the thickness of the N-type quantum dot layer 124 is 5 nm to 10 nm; the thickness of the quantum dot infrared absorption layer 122 is 200 to 1000 nm; and the thickness of the P-type quantum dot layer 125 is 5 nm to 10 nm.

[0055] By setting the thicknesses of the N-type quantum dot layer 124, the quantum dot infrared absorption layer 122, and the P-type quantum dot layer 125 to the ranges described above, electrons and holes can move in the corresponding directions, ensuring the transmission efficiency of electrons and holes. This results in a good detection effect for the infrared focal plane detector. The specific values ​​of the thicknesses of the N-type quantum dot layer 124, the quantum dot infrared absorption layer 122, and the P-type quantum dot layer 125 can be set according to the transmission requirements of electrons and holes, and are not limited here.

[0056] In some embodiments, based on FIG3, the N-type quantum dot layer 124 includes at least one of bismuth selenide, bismuth sulfide, bismuth telluride, zinc oxide, and cadmium selenide; the P-type quantum dot layer 125 includes at least one of poly(3-hexylthiophene), poly(3,4-ethylenedioxythiophene)polystyrene sulfonate, 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene, and polytriarylamine.

[0057] In addition, the N-type quantum dot layer 124 can also be one or more of the N-type quantum dot films of intrinsic quantum dot layers, and the P-type quantum dot layer 125 can also be one or more of the P-type quantum dot films of intrinsic quantum dot layers.

[0058] The N-type quantum dot layer 124 and P-type quantum dot layer 125 in this embodiment are composed of the above-mentioned materials, which facilitates direct coupling with the flexible curved substrate 110, thereby reducing the fabrication difficulty in the infrared focal plane detector fabrication process and improving the fabrication efficiency and yield of the infrared focal plane detector.

[0059] In some embodiments, based on Figures 2 and 3, the quantum dot infrared absorption layer 122 includes colloidal quantum dots, which include at least one of lead sulfide, lead selenide, mercuric telluride, mercuric selenide, cadmium sulfide, cadmium telluride, cadmium selenide, silver sulfide, silver telluride, silver selenide, and mercuric cadmium telluride.

[0060] In some embodiments, the colloidal quantum dots included in the quantum dot infrared absorption layer 122 are intrinsic (colloidal) quantum dots, and their absorption wavelength is related to the reaction time and temperature during the synthesis of intrinsic quantum dots. Specifically, during the synthesis of intrinsic colloidal quantum dots, the absorption wavelength and particle size of the intrinsic colloidal quantum dots can be precisely controlled by precisely adjusting the reaction time and temperature; for example, the longer the reaction time and the higher the reaction temperature, the longer the absorption wavelength and the larger the particle size of the intrinsic colloidal quantum dots. Thus, the quantum dot infrared absorption layer 122 in this embodiment can cover any one of short-wave infrared, mid-wave infrared, and long-wave infrared, thereby forming a monochromatic infrared focal plane detector. No limitation is made on the absorption wavelength and particle size of the intrinsic colloidal quantum dots.

[0061] For example, Figure 4 is a schematic diagram of the spectral absorption of an infrared focal plane detector provided in an embodiment of this disclosure. Referring to Figure 4, the horizontal axis X1 represents the wavenumber (i.e., the reciprocal of the wavelength), with units of cm⁻¹; the vertical axis Y1 represents the absorbance, which is a dimensionless unit and can be represented by au (abbreviation of arbitrary units); L31, L32, L33, L34, and L35 represent the spectral absorption curves of quantum dots with wavelengths of 1.7 μm, 2 μm, 2.5 μm, 3 μm, and 3.7 μm, respectively, indicating that quantum dots of different wavelengths can be synthesized when preparing an infrared focal plane detector, and an infrared focal plane detector with a spectral detection range of 1.7 μm to 3.7 μm can be realized.

[0062] In some embodiments, based on Figures 2 and 3, the infrared focal plane detector further includes: a data analysis and imaging circuit (not shown in the figures), and the flexible curved substrate 110 is electrically connected to the data analysis and imaging circuit.

[0063] In some embodiments, the data analysis and imaging circuit includes a signal processor. Specifically, when an object or human body enters the detection range of the infrared focal plane detector, the infrared radiation emitted by it (i.e., ambient infrared light) is received by the quantum dot infrared absorption layer of the infrared focal plane detector and converted into an electrical signal. The electrical signal is then transmitted to the data analysis and imaging circuit via the flexible curved substrate 110. The signal processor of the data analysis and imaging circuit amplifies and filters the signal, and performs infrared imaging based on the processed signal to determine the presence, movement, temperature changes, etc. of the object or human body.

[0064] In some embodiments, based on Figures 2 and 3, the radius of curvature of the flexible curved substrate 110 is greater than or equal to 3 mm.

[0065] Specifically, by setting the radius of curvature of the flexible curved substrate 110 to be greater than or equal to 3 mm, the focal point of the incident external infrared ambient light will be on the curved focal plane of the infrared focal plane detector, thus avoiding image distortion and ensuring good imaging effect, that is, achieving clear imaging with a large field of view and high resolution.

[0066] The thickness of the flexible curved substrate 110 is less than or equal to 50 μm. With the radius of curvature of the flexible curved substrate 110 greater than or equal to 3 mm, setting its thickness to less than or equal to 50 μm helps to further improve the imaging effect of the infrared focal plane detector. This setting can be adjusted according to the imaging requirements of the infrared focal plane detector and is not limited here.

[0067] Based on the above embodiments, this disclosure also provides an infrared focal plane detector system. Figure 5 is a schematic diagram of the structure of an infrared focal plane detector system provided in this disclosure. Referring to Figure 5, the infrared focal plane detector system includes an imaging lens 130 and any of the infrared focal plane detectors 100 provided in the above embodiments.

[0068] The imaging lens 130 is located on the light-incident surface side of the infrared focal plane detector 100. Specifically, when ambient infrared light illuminates the infrared focal plane detector system, the imaging lens 130 can converge ambient infrared light from various incident directions to multiple back focal points located on the infrared focal plane detector 100, thereby forming a clear image at the multiple back focal points.

[0069] Thus, compared to the existing infrared detectors that use multiple imaging lenses for imaging, the embodiments of this disclosure can focus the external infrared ambient light onto the infrared focal plane detector 100 using only one imaging lens 130. This reduces the number of optical components required for imaging in the infrared focal plane detector system, thereby reducing the size and weight of the infrared focal plane detector system, saving manufacturing costs, and facilitating assembly and portability.

[0070] This disclosure also provides a method for preparing an infrared focal plane detector, which can be used to prepare any of the infrared focal plane detectors provided in the above embodiments.

[0071] In some embodiments, FIG6 is a schematic flowchart of a method for fabricating an infrared focal plane detector according to an embodiment of the present disclosure. Referring to FIG6, the method includes:

[0072] S210 provides a flexible curved surface substrate.

[0073] For example, acetone, isopropanol and deionized water can be used in sequence to clean the flexible curved substrate in preparation for subsequent use.

[0074] S220. A quantum dot detection structure is formed on one side of the light-incident surface of a flexible curved substrate.

[0075] Among them, the quantum dot detection structure is used to output an electrical signal to the flexible curved substrate in response to the external infrared ambient light signal, and then to the readout circuit of the flexible curved substrate.

[0076] In some embodiments, based on FIG6, S220 specifically includes the following steps:

[0077] A quantum dot infrared absorption layer for a quantum dot detection structure is formed by stacking on one side of the light-incident surface of a flexible curved substrate using any of the following methods: spin coating, spray coating, or drop coating.

[0078] Specifically, compared to the various defects caused by the existing technology of bonding crystal epitaxial materials to flexible curved substrates through flip-chip bonding, the embodiments of this disclosure prepare the quantum dot infrared absorption layer onto the flexible curved substrate by spin coating, spray coating or drop coating, which makes the preparation process of flexible infrared focal plane detector simpler, thereby effectively reducing the preparation cost of flexible infrared focal plane detector and reducing the design complexity of flexible infrared focal plane detector.

[0079] For example, the thickness of the quantum dot infrared absorption layer can be 200nm to 1000nm, such as 200nm, 400nm, 600nm or other thickness values. In other embodiments, the thickness of the quantum dot infrared absorption layer can also be other numerical ranges or values, which can be set according to the imaging requirements of the infrared focal plane detector, and are not limited here.

[0080] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0081] The above description is merely a specific embodiment of this disclosure, enabling those skilled in the art to understand or implement it. 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 this disclosure. Therefore, this disclosure is not to be limited to the embodiments described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An infrared focal plane detector, comprising: The infrared focal plane detector comprises: a flexible curved substrate and a quantum dot detection structure; the quantum dot detection structure is located on the light-incident side of the flexible curved substrate; the quantum dot detection structure is configured to output an electrical signal to a readout circuit of the flexible curved substrate in response to an external infrared ambient light signal.

2. The infrared focal plane detector of claim 1, wherein, The quantum dot detection structure comprises: a plurality of first electrodes, which are arranged at intervals in the plane of the flexible curved substrate and are electrically connected to the readout circuit; a quantum dot infrared absorption layer, which is located on the side of the first electrodes away from the flexible curved substrate and fills the gaps between the first electrodes; a second electrode, which is arranged on the side of the quantum dot infrared absorption layer away from the flexible curved substrate.

3. The infrared focal plane detector of claim 1, wherein, The quantum dot detection structure comprises: a plurality of first electrodes, which are arranged at intervals in the plane of the flexible curved substrate and are electrically connected to the readout circuit; an N-type quantum dot layer, which is located on the side of the first electrodes away from the flexible curved substrate and fills the gaps between the first electrodes; a quantum dot infrared absorption layer, which is located on the side of the N-type quantum dot layer away from the first electrodes; a P-type quantum dot layer, which is located on the side of the quantum dot infrared absorption layer away from the N-type quantum dot layer; a second electrode, which is located on the side of the P-type quantum dot layer away from the quantum dot infrared absorption layer.

4. The infrared focal plane detector according to claim 3, wherein: the thickness of the N-type quantum dot layer is 5-10 nm; the thickness of the quantum dot infrared absorption layer is 200-1000 nm; the thickness of the P-type quantum dot layer is 5-10 nm.

5. The infrared focal plane detector of claim 3, wherein, The N-type quantum dot layer comprises at least one of bismuth selenide, bismuth sulfide, bismuth telluride, zinc oxide and cadmium selenide; The P-type quantum dot layer comprises at least one of poly-3-hexylthiophene, poly(3,4-ethylenedioxythiophene) polystyrene sulfonate, 2,2',7,7'-tetrakis[N,N-bis(4-methoxyphenyl)amino]-9,9'-spirobifluorene and polytriarylamine.

6. The infrared focal plane detector according to claim 2 or 3, wherein: The quantum dot infrared absorption layer comprises colloidal quantum dots, and the colloidal quantum dots comprise at least one of lead sulfide, lead selenide, mercury telluride, mercury selenide, cadmium sulfide, cadmium telluride, cadmium selenide, silver sulfide, silver telluride, silver selenide and mercury cadmium telluride.

7. The infrared focal plane detector of claim 1, wherein, The flexible curved substrate has a radius of curvature greater than or equal to 3 mm.

8. An infrared focal plane array detection system, characterized in that, The infrared focal plane detector comprises an imaging lens and any one of claims 1-7. The imaging lens is located on the light-incident side of the infrared focal plane detector.

9. A method of fabricating an infrared focal plane detector, comprising: The method comprises: providing a flexible curved substrate; forming a quantum dot detection structure on the light-incident side of the flexible curved substrate; The quantum dot detection structure is configured to output an electrical signal to a readout circuit of the flexible curved substrate in response to an external infrared ambient light signal.

10. The method of claim 9, wherein the method further comprises: depositing a passivation layer on the infrared focal plane array. The method comprises: providing a flexible curved substrate; forming a quantum dot detection structure on the light-incident side of the flexible curved substrate; The quantum dot detection structure is configured to output an electrical signal to a readout circuit of the flexible curved substrate in response to an external infrared ambient light signal. The method comprises: The quantum dot infrared absorption layer of the quantum dot detection structure is stacked on the light-incident side of the flexible curved substrate by any one of spin coating, spraying and drop coating.

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