Upconversion detector, preparation method and infrared visible upconversion imaging system

Abstract

The invention discloses an up-conversion detector, a preparation method and an infrared visible up-conversion imaging system, and belongs to the technical field of semiconductor devices. The up-conversion detector provided by the invention comprises a substrate, an anode layer, a hole injection layer, a first light-emitting layer, an electron transport layer, an infrared absorption layer, a hole transport layer, a second light-emitting layer, an electron injection layer and a cathode layer which are stacked in sequence, the first light-emitting layer and the second light-emitting layer are made of at least one of CdSe quantum dots, CdS quantum dots, InAlAs / AlGaAs quantum dots and InP quantum dots, the first light-emitting layer is used for utilizing electrons generated by the infrared absorption layer, and the second light-emitting layer is used for utilizing holes generated by the infrared absorption layer. According to the up-conversion detector, the infrared absorption layer receives near-infrared light irradiation, generated electrons are utilized by the first light-emitting layer, generated holes are utilized by the second light-emitting layer, the utilization rate of photon-generated carriers is improved, and the up-conversion detector has higher visible light brightness.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor devices, and in particular to an up-conversion detector, a preparation method and an infrared-visible up-conversion imaging system. Background Art

[0002] Infrared (IR) upconversion devices are a type of optoelectronic devices that work in the infrared band and have the ability to convert incident infrared radiation into visible light or other detectable radiation. This conversion technology has broad application prospects in medical imaging, optical communications, infrared sensing and bioanalysis.

[0003] In recent years, quantum dot materials, as a unique semiconductor nanomaterial, have been widely used in the field of optoelectronics. In the development of infrared up-conversion devices, near-infrared up-conversion devices with quantum dot materials as absorption layers or emission layers have significantly improved their performance and application range, and have the ability to precisely control the energy band structure, enabling them to efficiently absorb incident near-infrared radiation and achieve energy up-conversion in the optical process.

[0004] However, this type of infrared up-conversion device still has problems such as low utilization of photogenerated carriers, low conversion efficiency and low luminous brightness, which leads to poor performance of the up-conversion device. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a double-sided luminous upconversion detector, which can effectively improve the utilization rate and conversion efficiency of photogenerated carriers and improve the luminous intensity of the upconversion detector.

[0006] The present invention also provides a method for preparing the up-conversion detector.

[0007] The present invention also provides a visible up-conversion imaging system comprising the above up-conversion detector.

[0008] In a first aspect, an embodiment of the present invention provides an up-conversion detector, wherein the up-conversion detectors are stacked in sequence:

[0009] A substrate, an anode layer, a hole injection layer, a first light emitting layer, an electron transport layer, an infrared absorption layer, a hole transport layer, a second light emitting layer, an electron injection layer and a cathode layer;

[0010] The materials of the first light-emitting layer and the second light-emitting layer respectively include at least one of CdSe quantum dots, CdS quantum dots, InAlAs / AlGaAs quantum dots and InP quantum dots, and the first light-emitting layer is used to utilize the electrons generated by the infrared absorption layer, and the second light-emitting layer is used to utilize the holes generated by the infrared absorption layer.

[0011] The upconversion detector of the embodiment of the present invention adopts a double-luminescent layer design. After the infrared absorption layer receives near-infrared light irradiation, the generated electrons can be utilized by the first luminescent layer, and the generated holes can be utilized by the second luminescent layer, which greatly improves the utilization rate of photogenerated carriers, improves the PP conversion efficiency, and achieves more efficient photoelectron energy conversion. Different from traditional infrared upconversion devices, the present invention can achieve higher visible light brightness under the same intensity of near-infrared light irradiation, further improving contrast and sensitivity.

[0012] According to some embodiments of the present invention, the hole injection layer includes a first hole injection layer and a second hole injection layer which are sequentially stacked, and the first hole injection layer and the second hole injection layer are made of different materials.

[0013] According to some embodiments of the present invention, the materials of the first hole injection layer and the second hole injection layer include at least one of PEDOT, TFB, P3HT, TPDPTAA, and PCBM, respectively, and / or the thicknesses of the first hole injection layer and the second hole injection layer are independently selected from any value between 30 and 100 nm.

[0014] According to some embodiments of the present invention, the thicknesses of the first light-emitting layer and the second light-emitting layer are independently selected from any value within the range of 20 to 50 nm.

[0015] According to some embodiments of the present invention, the material of the infrared absorption layer includes PbS quantum dots, and / or the thickness of the infrared absorption layer is 200-500 nm.

[0016] According to some embodiments of the present invention, the material of the electron transport layer includes at least one of ZnO, TiO2 and Alq3; and / or the thickness of the electron transport layer is 30 to 100 nm.

[0017] According to some embodiments of the present invention, the material of the hole transport layer includes at least one of TFB, P3HT and TPD; and / or the thickness of the hole transport layer is 30-100 nm.

[0018] According to some embodiments of the present invention, the material of the electron injection layer includes at least one of ZnO, TiO2 and Alq3; and / or the thickness of the electron injection layer is 30 to 100 nm.

[0019] In a second aspect, a method for preparing an upconversion detector is provided, comprising the following steps:

[0020] Carving out an anode on a substrate;

[0021] An anode layer, a first hole injection layer, a second hole injection layer, a first light-emitting layer, an electron transport layer, a hole transport layer, a second light-emitting layer, and an electron injection layer are sequentially coated on the cathode;

[0022] Vapor-depositing a cathode layer on the electron injection layer and then encapsulating it;

[0023] The materials of the first light-emitting layer and the second light-emitting layer include at least one of CdSe quantum dots, CdS quantum dots, InAlAs / AlGaAs quantum dots and InP quantum dots.

[0024] In a third aspect, an infrared-visible up-conversion imaging system is provided, wherein the infrared-visible up-conversion imaging system comprises the up-conversion detector in any of the above-mentioned embodiments, and the infrared-visible up-conversion imaging system further comprises an arrayed chip, wherein the arrayed chip has electrodes, and the electrodes are bonded to the cathode layer.

[0025] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention is further described below with reference to the accompanying drawings and embodiments, wherein:

[0027] Figure 1 A schematic diagram of the structure of an up-conversion detector according to an embodiment of the present invention;

[0028] Figure 2 for Figure 1 Schematic diagram of the structure of the mid-up conversion detector under no illumination;

[0029] Figure 3 for Figure 1 Schematic diagram of the structure of the up-conversion detector under illumination;

[0030] Figure 4 A system flow chart of a method for preparing an up-conversion detector according to an embodiment of the present invention;

[0031] Figure 5 This is a schematic diagram of the structure of an infrared visible up-conversion imaging system according to an embodiment of the present invention;

[0032] Figure 6 for Figure 1 Schematic diagram of the specific structure of the mid-infrared visible upconversion imaging system.

[0033] Reference numerals:

[0034] 1000. Infrared visible upconversion imaging system;

[0035] 100. Up-conversion detector;

[0036] 10. substrate; 20. anode layer; 30. hole injection layer; 31. first hole injection layer; 41. second hole injection layer; 50. first light-emitting layer; 60. electron transport layer; 70. infrared absorption layer; 80. hole transport layer; 90. second light-emitting layer; 110. electron injection layer; 120. cathode layer;

[0037] 200. Arrayed chip. DETAILED DESCRIPTION

[0038] The following will be combined with the embodiments to clearly and completely describe the concept of the present invention and the technical effects produced, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0039] In the description of the present invention, it should be understood that descriptions involving orientation, such as orientation or positional relationship indicated as up, down, etc., are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0040] In the description of the present invention, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0041] In the description of the present invention, "a plurality" means more than two. If there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0042] As mentioned in the background technology, quantum dot materials, as a unique semiconductor nanomaterial, have been widely used in the field of optoelectronics. In the development of infrared up-conversion devices, the latest infrared up-converters use quantum dot materials as absorption or emission layers, which significantly improves the performance and application range, and has the ability to accurately regulate the band structure, enabling them to efficiently absorb incident near-infrared radiation and achieve energy up-conversion in the optical process. This unique property based on quantum dot materials enables infrared light to be converted into visible light or other radiation that is easier to detect and analyze. In addition, these quantum dot materials also have high radiation stability, allowing infrared up-conversion devices to maintain high performance during long-term use.

[0043] However, this type of up-conversion device still has problems including low utilization of photogenerated carriers and equipment performance that needs to be optimized. For example, the conversion efficiency of infrared to visible light of pure electronic devices in the up-conversion device decreases with the increase of near-infrared light power density at the same voltage, and the stable value is only 0.42%, which greatly limits the performance of the device.

[0044] In addition, in single-carrier devices using quantum dot materials as absorption layers, since the electrons in the electron-hole pairs generated after the quantum dots receive near-infrared light are blocked by the blocking layer, the radiative recombination of the device only uses the holes generated by the quantum dot material absorbing infrared light, and the electrons generated by absorbing near-infrared light are not used. The maximum utilization rate of photogenerated carriers is only 50%. Therefore, how to solve the problems that up-conversion devices prepared using quantum dot materials cannot fully utilize photogenerated carriers and the performance needs to be optimized is one of the pain points of current up-conversion devices.

[0045] Based on this, the present application provides a double-sided luminous up-conversion detector 100, see Figure 1 The upconversion detector 100 includes a substrate 10, an anode layer 20, a hole injection layer 30, a first light-emitting layer 50, an electron transport layer 60, an infrared absorption layer 70, a hole transport layer 80, a second light-emitting layer 90, an electron injection layer 110 and a cathode layer 120 which are stacked in sequence. The materials of the first light-emitting layer 50 and the second light-emitting layer 90 include at least one of CdSe quantum dots, CdS quantum dots, InAlAs / AlGaAs quantum dots and InP quantum dots, respectively, and the first light-emitting layer 50 is used to utilize the electrons generated by the infrared absorption layer 70, and the second light-emitting layer 90 is used to utilize the holes generated by the infrared absorption layer 70.

[0046] The present invention uses quantum dot materials as the first light-emitting layer 50 and the second light-emitting layer 90. Since the diffusion length of the quantum dot material is only 100-200nm, theoretically, high-resolution imaging with a pixel interval of only 200nm can be achieved, which greatly exceeds the limitations of traditional technology and realizes the high resolution of the upconversion detector 100.

[0047] Specifically, when CdSe quantum dots are selected as the material of the first light-emitting layer 50 or the second light-emitting layer 90, a wider display color gamut and a longer display life can be obtained due to its high color conversion efficiency (>90%), high stability, and narrow light-emitting spectrum. The use of quantum dot materials not only enhances the radiation stability of the up-conversion detector 100, but also ensures high performance in long-term use, meeting the requirements of long-term operation.

[0048] At the same time, thanks to the flexible characteristics of quantum dot materials, the upconversion detector 100 provided by the present invention can be applied to a wider range of scenarios, including application fields that require flexible materials. Compared with traditional rare earth materials or their quantum dots, the quantum dot materials used in the first light-emitting layer 50 and the second light-emitting layer 90 of the present invention have lower costs and simpler preparation processes, and most importantly, have better luminescence performance and contrast. For example, CdSe quantum dot materials have high color conversion efficiency (>90%), high stability, and narrow luminescence spectrum, which can obtain a wider display color gamut and a longer display life.

[0049] The working mechanism of the upconversion detector 100 is as follows: after the quantum dot infrared absorption layer 70 absorbs infrared rays, holes and electrons are generated; the holes pass through the hole transport layer 80, and a hole-electron recombination reaction occurs with the material in the second light-emitting layer 90 to generate visible light, and the electrons pass through the electron transport layer 60, and an electron-hole recombination reaction occurs with the material in the first light-emitting layer 50 to generate visible light.

[0050] Therefore, since the present application adopts a double-light-emitting layer design, after the infrared absorption layer 70 receives near-infrared light irradiation, the generated electrons can be utilized by the first light-emitting layer 50, and the generated holes can be utilized by the second light-emitting layer 90, which greatly improves the utilization rate of photogenerated carriers, improves the PP conversion efficiency, and achieves more efficient photoelectron energy conversion. Different from traditional infrared up-conversion devices, the present invention can improve the utilization efficiency of light under the same intensity of near-infrared light irradiation, more infrared light energy can be captured and utilized, and has a higher visible light brightness, further enhancing the sensitivity and efficiency of the up-conversion detector 100.

[0051] In one embodiment, see Figure 1 The hole injection layer 30 includes a first hole injection layer 31 and a second hole injection layer 41 which are stacked in sequence to form a double-layer hole injection layer 30 , and the first hole injection layer 31 and the second hole injection layer 41 are made of different materials.

[0052] It can be understood that the energy level difference between the anode layer 20 and the first light-emitting layer 50 is relatively large. Through the first hole injection layer 31 and the second hole injection layer 41 made of different materials, a double-stage climb is formed, which reduces the barrier gradient between different semiconductor materials, significantly improves the carrier injection efficiency, and improves the conversion efficiency. Under the irradiation of near-infrared light of the same intensity, the up-conversion detector 100 provided by the present invention has higher visible light brightness, further improving the contrast and sensitivity.

[0053] In one embodiment, the thickness of the first light-emitting layer 50 and / or the second light-emitting layer 90 is independently selected from any value in the range of 20 nm to 50 nm, for example, 25 to 40 nm, and more specifically, about 30 nm or about 35 nm, to ensure the light-emitting effect.

[0054] According to some embodiments of the present invention, the materials of the first hole injection layer 31 and the second hole injection layer 41 are independently selected from at least one of PEDOT (poly (3,4-ethylenedioxythiophene), CAS: 155090-83-8), TFB (boron trifluoride, CAS: 220797-16-0), P3HT (CAS No.: 104934-50-1), PTAA (CAS: 1333317-99-9), TPD (CAS: 65181-78-4) and PCBM (CAS: 160848-22-6). And / or, the thickness of the first hole injection layer 31 and the second hole injection layer 41 is independently selected from any value in the range of 30 to 100 nm. For example, it can be 40 to 60 nm. Further specifically, it can be about 45 nm, 50 nm, 55 nm, 60 nm or about 65 nm.

[0055] In one embodiment, the material of the infrared absorption layer 70 includes PbS quantum dots, and / or the thickness of the infrared absorption layer 70 is 200nm to 500nm, for example, specifically 300 to 450nm. More specifically, it can be about 350nm or about 400nm. The quantum dot infrared absorption layer 70 with infrared absorption characteristics can enable the up-conversion detector 100 to have infrared spectrum detection capability, expand the application range of the imaging system, especially the imaging capability in low illumination or dark environment.

[0056] In one embodiment, the substrate 10 is selected from a flexible material or a rigid material. When a flexible material is selected, the upconversion detector 100 is used in a scene requiring flexibility, such as a wearable device, and the flexible material may include at least one of an organic polymer or ultra-thin glass. When a rigid material is selected, the rigid material includes at least one of a glass sheet, a quartz sheet, and a silicon sheet.

[0057] According to some embodiments of the present invention, the material of the anode layer 20 includes at least one of In2O5Sn (indium tin oxide, referred to as ITO), IGZO, aluminum tin oxide and aluminum zinc oxide, and / or the thickness of the anode layer 20 is 100 to 300 nm. For example, it can be 110 to 180 nm. More specifically, it can be about 120 nm, 130 nm, 150 nm or about 160 nm.

[0058] According to some embodiments of the present invention, the anode layer 20 has both transparency and conductivity to ensure the absorption effect of the infrared absorption layer 70 .

[0059] In one embodiment, the material of the electron transport layer 60 includes at least one of ZnO, TiO2 and Alq3, and / or the thickness of the electron transport layer 60 is 30 to 100 nm, for example, 50 to 90 nm, and more specifically, about 60 nm, 75 nm or about 80 nm.

[0060] In one embodiment, the material of the hole transport layer 80 includes at least one of TFB, P3HT and TPD, and / or the thickness of the hole transport layer 80 is 30 to 100 nm, for example, 50 to 90 nm, and more specifically, about 60 nm, 65 nm, 70 nm, 80 nm or about 85 nm.

[0061] In one embodiment, the material of the electron injection layer 110 includes at least one of ZnO, TiO2 and Alq3, and / or the thickness of the electron injection layer 110 is 30 to 100 nm, for example, 50 to 90 nm, and more specifically, about 70 nm, 75 nm, 80 nm or about 85 nm.

[0062] According to some embodiments of the present invention, the material of the cathode layer 120 includes at least one of Au, Ag, Cu and Al, and / or the thickness of the cathode layer 120 is 100-300 nm, for example, about 150 nm, 200 nm or about 250 nm.

[0063] Thus, the present invention uses a double-layer luminescent layer (a first luminescent layer 50 and a second luminescent layer 90) and combines other layers with suitable materials and designs, so that the upconversion detector 100 can generate a high-brightness light source during the luminescence process, thereby helping to improve image clarity and visibility.

[0064] According to the above analysis, in the up-conversion detector 100 provided by the present invention, there are many choices of materials for each layer. The different quantum dots and other layer material combinations of the first light-emitting layer 50 and the second light-emitting layer 90 can provide optimized spectral characteristics and luminous efficiency for specific applications, thereby achieving higher equipment performance and application flexibility.

[0065] According to some embodiments of the present invention, the up-conversion detector 100 is an infrared-visible up-conversion detector 100, which can realize the conversion of infrared light into visible light.

[0066] See also Figure 2 and Figure 3 , which are distribution diagrams of electrons and holes under no light conditions and light conditions, respectively, wherein solid circles represent holes and hollow circles represent electrons. Under light conditions, the infrared absorption layer 70 absorbs external near-infrared rays, the first light-emitting layer 50 uses electrons to generate visible light, and the second light-emitting layer 90 uses holes to generate visible light.

[0067] According to another aspect of the present application, a method for preparing an up-conversion detector is also provided, which is used to prepare the up-conversion detector 100 in the above embodiment. Figure 4 The preparation method specifically comprises the following steps:

[0068] S100, carving an anode on the substrate 10;

[0069] S200, sequentially coating on the cathode to form an anode layer 20, a first hole injection layer 31, a second hole injection layer 41, a first light-emitting layer 50, an electron transport layer 60, a hole transport layer 80, a second light-emitting layer 90, and an electron injection layer 110;

[0070] S300, evaporating a cathode layer 120 on the electron injection layer 110 and then encapsulating;

[0071] The materials of the first light-emitting layer 50 and the second light-emitting layer 90 include at least one of CdSe quantum dots, CdS quantum dots, InAlAs / AlGaAs quantum dots and InP quantum dots.

[0072] Regarding the materials and thicknesses of the anode layer 20 , the first hole injection layer 31 , the second hole injection layer 41 , the electron transport layer 60 , the hole transport layer 80 , and the electron injection layer 110 , please refer to the above and will not be described in detail here.

[0073] Specifically, the anode can be engraved on the substrate 10 by laser marking or photolithography, and then magnetron sputtering or other applicable preparation methods can be used, such as coating the substrate 10 with a conductive material (ln2O5Sn, IGZO, aluminum tin oxide or aluminum zinc oxide, etc.) to form a conductive film layer to prepare the anode layer 20, so as to ensure the conductivity and transparency of the anode layer 20.

[0074] Specifically, at least one of materials such as PEDOT, TFB, P3HT, PTAA, TPD, PCBM, etc. can be selected by spin coating or inkjet printing, for example, a poly (3,4-ethylenedioxythiophene) (PEDOT) film can be coated on the anode layer 20 to form the first hole injection layer 31.

[0075] Specifically, the boron trifluoride (TFB) material may be coated on the first hole injection layer 31 by a solution method such as spin coating or inkjet printing to form the second hole injection layer 41 .

[0076] Specifically, suitable materials can be selected from CdSe quantum dots, CdS quantum dots, InAlAs / AlGaAs quantum dots and InP quantum dots, and the first light-emitting layer 50 can be prepared by inkjet printing, spin coating, atomic layer deposition, etc., which generates electron-hole pairs after absorbing near-infrared light. For example, the CdSe quantum dots (QDs) material is uniformly dispersed in a suitable solvent using a solution method, and then coated on the second hole injection layer 41 to form the first light-emitting layer 50.

[0077] The appropriate solvent includes but is not limited to toluene solvent, etc. For example, InP quantum dots can be dissolved in toluene to form a slurry solution with a concentration of 5 mg / mL, which is then spin-coated on the second hole injection layer 41 .

[0078] Specifically, materials such as ZnO, TiO2, Alq3 can be selected, and methods such as evaporation, atomic layer deposition, and magnetron sputtering can be used to prepare the electron transport layer 60, which helps the transport of electrons. For example, a zinc oxide (ZnO) film is deposited on the first light-emitting layer 50 by magnetron sputtering and other processes to serve as the electron transport layer 60.

[0079] Specifically, PbS quantum dots can be selected to form an infrared absorption layer 70 with infrared absorption characteristics through solution processes such as spin coating, spraying, inkjet printing, and doctor blade coating. For example, lead sulfide (PbS) quantum dots (QDs) material is uniformly dispersed in a suitable solvent using a solution method, and then coated on the electron transport layer 60 to form the infrared absorption layer 70.

[0080] The solvent for forming the infrared absorption layer 70 includes but is not limited to n-octane solvent, etc. For example, lead sulfide (PbS) quantum dots (QDs) material can be uniformly dispersed in n-octane solvent to form an infrared absorption layer 70 slurry with a concentration of 50 mg / mL.

[0081] Specifically, materials such as TFB, P3HT, TPD, etc. can be used to prepare the hole transport layer 80 by spin coating, etc., which is helpful for hole transport. For example, the TFB material is coated on the quantum dot infrared absorption layer 70 by solution method to form the hole transport layer 80.

[0082] Specifically, the preparation process of the first light-emitting layer 50 is the same as that of the first light-emitting layer 50. Suitable materials are selected from CdSe quantum dots, CdS quantum dots, InAlAs / AlGaAs quantum dots and InP quantum dots, and the second light-emitting layer 90 is prepared by inkjet printing, spin coating, atomic layer deposition, etc., which generates electron-hole pairs after absorbing near-infrared light. For example, the CdSe quantum dots (QDs) material is uniformly dispersed in a suitable solvent by a solution method, and then spin-coated on the hole transport layer 80 to form the second light-emitting layer 90.

[0083] Specifically, ZnO, TiO2, Alq3 materials can be selected, and the electron injection layer 110 can be prepared by evaporation, atomic layer deposition, magnetron sputtering and other methods to facilitate the injection of electrons. For example, a zinc oxide (ZnO) film is deposited on the second light-emitting layer 90 by magnetron sputtering process to serve as the electron injection layer 110.

[0084] Specifically, Au, Ag, Cu, Al and other metals may be selected to prepare a cathode layer 120 having good conductivity by evaporation or the like, and then encapsulated to obtain an up-conversion detector 100 with a double-sided light-emitting structure.

[0085] For ease of explanation, two embodiments of a method for preparing a double-layer luminescent upconversion detector are provided below:

[0086] First embodiment:

[0087] S1. Use ultra-thin glass (0.2 mm) made of flexible material as the substrate 10, remove impurities on the surface of the ultra-thin glass through processes such as grinding and polishing, and obtain a smooth surface of the substrate 10.

[0088] S2. A 150 nm thick conductive indium tin oxide (ITO) thin film is deposited on the substrate 10 obtained in step S1 by magnetron sputtering to form an anode layer 20 having both conductivity and transparency.

[0089] S3. Using a solution method (i.e., spin coating), a poly(3,4-ethylenedioxythiophene) (PEDOT) film is coated on the ITO anode layer 20 to form a 50 nm thick first hole injection layer 31; wherein the solvent of the solution used is water with a concentration of 10 mg / mL; and then heat treated at 110°C for 10 min.

[0090] S4. Using a solution method, a boron trifluoride (TFB) material is coated (spin-coated) on the first hole injection layer 31 to form a second hole injection layer 41 with a thickness of 50 nm. The solvent of the solution used is toluene with a concentration of 20 mg / mL. Then, heat treatment is performed at 150° C. for 10 min.

[0091] S5. Using a solution method, CdSe quantum dots (QDs) material is uniformly mixed in toluene solvent to form a first light-emitting layer 50 slurry with a concentration of 5 mg / mL, and the slurry is used as a raw material to coat (spin coat) the second hole injection layer 41 to form a 35 nm first light-emitting layer 50. Then, heat treatment is performed at 90° C. for 5 min.

[0092] S6. Using a process such as magnetron sputtering, a 75 nm thick zinc oxide (ZnO) thin film is deposited on the first light-emitting layer 50 to serve as the electron transport layer 60 .

[0093] S7. Using a solution method, the lead sulfide (PbS) quantum dot (QDs) material is uniformly dispersed in an n-octane solvent to form an infrared absorption layer 70 slurry with a concentration of 50 mg / mL, and the slurry is used as a raw material to coat the electron transport layer 60 to form a 350 nm thick quantum dot infrared absorption layer 70.

[0094] S8. Using a solution method, the TFB material is coated on the quantum dot infrared absorption layer 70 to form a 65 nm thick hole transport layer 80. The solvent used in the solution is toluene with a concentration of 20 mg / mL.

[0095] S9. Referring to the method of step S5, a second light-emitting layer 90 with a thickness of 35 nm is disposed on the surface of the hole transport layer 80.

[0096] S10. Using a magnetron sputtering process, a zinc oxide (ZnO) thin film is deposited on the second light-emitting layer 90 to serve as the electron injection layer 110 with a thickness of 75 nm.

[0097] S11. A metal material such as aluminum (Al) is deposited on the electron injection layer 110 by evaporation to form the uppermost cathode layer 120 with a thickness of 200 nm.

[0098] S12. Packaging.

[0099] Second embodiment:

[0100] S1. Use ultra-thin glass (0.2 mm) made of flexible material as substrate 10, clean and pre-treat it to ensure the surface is clean and smooth.

[0101] S2. On the clean ultra-thin glass substrate 10, a layer of transparent indium tin oxide (ln2O5Sn) is deposited by magnetron sputtering to form an anode layer 20 with a thickness of 120 nm.

[0102] S3. Spin coating the anode with PEDOT material to form a first hole injection layer 31 with a thickness of 60 nm, and perform appropriate heat treatment. The heat treatment condition is 110°C / 20min to optimize the conductivity and transparency of the PEDOT layer. The solvent of the solution used for spin coating is water, and the concentration is 10 mg / mL.

[0103] S4. Spin-coat the P3HT material on the first hole injection layer 31 to form a second hole injection layer 41 with a thickness of 60 nm, and perform heat treatment to optimize its performance. The heat treatment condition is 140°C / 15min to improve the structural stability of the second hole injection layer 41. The solvent of the solution used for spin coating is toluene, and the concentration is 20 mg / mL.

[0104] S5. InP quantum dots (purchased from Suzhou Xingshuo Nanotechnology Co., Ltd., model InP / ZnS-560-50) are coated on the second hole injection layer 41 by spin coating to form a 35nm thick first light-emitting layer 50, and then properly baked to improve its electron-hole recombination efficiency. The baking condition is 120℃ / 30min. The solvent of the slurry used for spin coating is toluene, and the slurry concentration is 5mg / mL.

[0105] S6. Form an electron transport layer 60 with a thickness of 90 nm on the first light emitting layer 50 by sputtering a ZnO material to improve the electron transport efficiency.

[0106] S7. Spin-coat the PbS quantum dot material on the electron transport layer 60 to form a 450 nm thick quantum dot infrared absorption layer 70 for efficiently absorbing infrared light. The solvent of the slurry used for spin coating is n-octane with a concentration of 50 mg / mL.

[0107] S8. Spin-coat the TFB material on the quantum dot infrared absorption layer 70 to form a hole transport layer 80 with a thickness of 80 nm to optimize the hole transport efficiency. The solvent of the slurry used for spin coating is toluene with a concentration of 20 mg / mL.

[0108] S9. CdS quantum dots are coated on the hole transport layer 80 by spin coating to form a 25 nm thick second light emitting layer 90 to achieve efficient light emission. The concentration of the slurry used for spin coating is 5 mg / mL, and the solvent is toluene. Then, heat treatment is performed at 90° C. for 5 min.

[0109] S10. Spin coating Alq3 material on the second light emitting layer 90 to form a 90 nm thick electron injection layer 110 to improve the electron injection efficiency. The concentration of the slurry used is 300 mg / mL, and the solvent used is chloroform. Then heat treatment is performed at 250° C. for 10 min.

[0110] S11. Aluminum (Al) material is deposited on the electron injection layer 110 by evaporation to form a 150 nm thick cathode;

[0111] S12. Packaging.

[0112] The upconversion detector 100 prepared by the preparation method of the upconversion detector of the present invention can simultaneously utilize two photogenerated carriers (electrons and holes) for radiative recombination luminescence, so the photon conversion efficiency is theoretically twice that of a single-sided light-emitting device. It should be noted that the embodiments of the present invention are only a few options within the scope provided by the present invention, and do not represent the optimal choice. For example, the quantum dot types of the first light-emitting layer 50 and the second light-emitting layer 90 and the quantum dot types of the infrared absorption layer 70 may be recombined to obtain an upconversion detector 100 with better performance.

[0113] According to the third aspect of this application, refer to Figures 5 and 6 , an infrared visible upconversion imaging system 1000 is also provided, comprising an upconversion detector 100 and an arrayed chip 200 as in any of the above embodiments, wherein the arrayed chip 200 has electrodes, and the electrodes are bonded to a cathode layer 120 .

[0114] The infrared visible up-conversion imaging system 1000 adopts all the technical solutions of the up-conversion detector 100 of the above-mentioned embodiment, and thus has the beneficial effects brought by the technical solutions of any of the above-mentioned up-conversion detectors 100. In addition, by selecting an arrayed chip with a readout circuit as the substrate structure of the infrared visible up-conversion imaging system 1000 and combining the cathode layer 120 with the electrode of the arrayed chip 200, the infrared visible up-conversion imaging system 1000 can be realized.

[0115] The above is a detailed description of the embodiments of the present invention, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A double-sided luminescent upconversion detector, characterized in that: The up-conversion detector comprises: A substrate, an anode layer, a hole injection layer, a first light emitting layer, an electron transport layer, an infrared absorption layer, a hole transport layer, a second light emitting layer, an electron injection layer and a cathode layer; The materials of the first light-emitting layer and the second light-emitting layer respectively include at least one of CdSe quantum dots, CdS quantum dots, InAlAs / AlGaAs quantum dots and InP quantum dots, and the first light-emitting layer is used to utilize the electrons generated by the infrared absorption layer, and the second light-emitting layer is used to utilize the holes generated by the infrared absorption layer.

2. The up-conversion detector according to claim 1, characterized in that The hole injection layer includes a first hole injection layer and a second hole injection layer which are stacked in sequence, and the first hole injection layer and the second hole injection layer are made of different materials.

3. The up-conversion detector according to claim 2, characterized in that: The materials of the first hole injection layer and the second hole injection layer include at least one of PEDOT, TFB, P3HT, TPDPTAA, and PCBM, respectively, and / or the thicknesses of the first hole injection layer and the second hole injection layer are independently selected from any value in the range of 30 to 100 nm.

4. The up-conversion detector according to any one of claims 1 to 3, characterized in that: The thicknesses of the first light-emitting layer and the second light-emitting layer are independently selected from any value within the range of 20 to 50 nm.

5. The up-conversion detector according to any one of claims 1 to 3, characterized in that: The material of the infrared absorption layer includes PbS quantum dots, and / or the thickness of the infrared absorption layer is 200-500 nm.

6. The up-conversion detector according to any one of claims 1 to 3, characterized in that: The material of the electron transport layer includes at least one of ZnO, TiO2 and Alq3; and / or the thickness of the electron transport layer is 30 to 100 nm.

7. The up-conversion detector according to any one of claims 1 to 3, characterized in that: The material of the hole transport layer includes at least one of TFB, P3HT and TPD; and / or the thickness of the hole transport layer is 30-100 nm.

8. The up-conversion detector according to any one of claims 1 to 3, characterized in that: The material of the electron injection layer includes at least one of ZnO, TiO2 and Alq3; and / or the thickness of the electron injection layer is 30 to 100 nm.

9. A method for preparing an upconversion detector, characterized in that: The preparation method comprises the following steps: Carving out an anode on a substrate; An anode layer, a first hole injection layer, a second hole injection layer, a first light-emitting layer, an electron transport layer, a hole transport layer, a second light-emitting layer, and an electron injection layer are sequentially coated on the cathode; Vapor-depositing a cathode layer on the electron injection layer and then encapsulating it; The materials of the first light-emitting layer and the second light-emitting layer include at least one of CdSe quantum dots, CdS quantum dots, InAlAs / AlGaAs quantum dots and InP quantum dots.

10. An infrared visible upconversion imaging system, characterized in that: The infrared visible upconversion imaging system comprises the upconversion detector according to any one of claims 1 to 8; The infrared visible up-conversion imaging system further comprises an arrayed chip, on which there are electrodes, and the electrodes are bonded to the cathode layer.

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