HgTe quantum dot detector and preparation method thereof
By combining centrifugation with modification solution treatment, the interfacial contact between the electron transport layer, quantum dot active layer, and hole transport layer of the quantum dot detector was optimized, solving the problems of uneven film thickness and high stress, and achieving higher photoelectric performance and stability.
Patent Information
- Application Number
- CN202511139537.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-14
- Publication Date
- 2025-11-14
AI Technical Summary
Existing methods for fabricating quantum dot detectors suffer from problems such as uneven film thickness, numerous defects, and high stress, leading to poor performance.
Centrifugation combined with modification solution treatment was used to modify the Bi2Se3 electron transport layer, HgTe quantum dot active layer and Ag2Te hole transport layer respectively. An acetonitrile solution of ethylenedithiol, triethylamine, dodecylthiol, sodium iodide and polyvinylcarbazole was used for interface modification to optimize the interfacial contact performance.
It reduces thin film stress, minimizes wrinkles and microcracks, improves carrier extraction and transport paths, and enhances the photoelectric performance and stability of the detector.
Smart Images
Figure CN120957580A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of quantum dot detector technology, specifically relating to an HgTe quantum dot detector and its preparation method. Background Technology
[0002] Quantum dots, as low-dimensional semiconductor materials, range in size from a few nanometers to tens of nanometers and possess excellent photoelectric properties, finding wide applications in light-emitting devices, solar cells, and photodetectors. Quantum dots can be synthesized using simple, low-cost chemical methods with high process controllability and repeatability, and are compatible with various substrate materials. Unlike traditional bulk semiconductor materials, quantum dots, due to the quantum size effect, allow for continuous tunability of their bandgap through precise control of their size range, making them promising candidates for applications in light-emitting displays and micro-spectroscopy.
[0003] Among colloidal quantum dot materials, mercury telluride (HgTe) is a negative bandgap material. Compared with other semiconductor quantum dots, HgTe has an exciton radius of 39 nm, making it easy to obtain a strong quantum confinement effect. By adjusting the size of HgTe colloidal quantum dots, the absorption band edge of HgTe colloidal quantum dots can be tuned in the short-wave infrared, mid-wave infrared, long-wave infrared, and terahertz ranges, making it an excellent infrared detection material.
[0004] Traditional methods for fabricating quantum dot detectors include spin coating and inkjet printing. Spin coating utilizes the centrifugal force of a spin coater to rapidly spread the solution into a film, offering advantages such as high efficiency, low cost, and ease of operation. However, it suffers from low solution utilization, high defect rates in the film, and a radially gradient thickness distribution, resulting in poor thickness uniformity. Inkjet printing involves spraying ink through a micron-sized nozzle onto a substrate surface to form a film. It boasts high solution utilization but is highly dependent on ink quality, has low efficiency, and exhibits a high degree of defect rate in the thin film. Furthermore, the coffee ring effect leads to poor film thickness uniformity. With the development of flexible substrates, the substrate can be fixed inside a centrifuge tube. A solution containing the thin film material is added to the centrifuge tube to immerse the substrate, and centrifugation forms a thin film layer on the substrate. Detector films fabricated using centrifugation exhibit tight particle adhesion and fewer defects. However, the excessively tight particle bonding in the active layer results in high internal stress, making the film surface prone to wrinkles or cracks. Summary of the Invention
[0005] Therefore, the purpose of this invention is to provide an HgTe quantum dot detector and a method for its fabrication.
[0006] In a first aspect, the present invention provides a method for fabricating an HgTe quantum dot detector, comprising the following steps: 1) Fix the flexible substrate on the inner wall of the centrifuge tube, add Bi2Se3NCs solution to the centrifuge tube to immerse the flexible substrate, and centrifuge to prepare a Bi2Se3 film on the flexible substrate; 2) Remove the Bi2Se3NCs solution from the centrifuge tube after step 1), and add an electron transport layer modification solution to immerse the Bi2Se3NCs film for modification. After modification, remove the electron transport layer modification solution, add a cleaning solution for treatment, and obtain the Bi2Se3 electron transport layer. The electron transport layer modification solution is an acetonitrile solution containing ethylenedithiol and triethylamine. 3) Add HgTe quantum dot solution to the centrifuge tube treated in step 2) to immerse the Bi2Se3 electron transport layer, centrifuge, and prepare a layer of HgTe quantum dot film on the Bi2Se3 electron transport layer; 4) Remove the HgTe quantum dot solution from the centrifuge tube after step 3), and add quantum dot modification solution to immerse the HgTe quantum dot film for modification. After modification, remove the quantum dot active layer modification solution, add cleaning solution for treatment, and obtain the HgTe quantum dot active layer. The quantum dot modification solution is an acetonitrile solution containing dodecyl mercaptan and sodium iodide. 5) Add Ag2Te quantum dot solution to the centrifuge tube after step 4) to immerse the HgTe quantum dot active layer, centrifuge, and prepare an Ag2Te thin film on the HgTe quantum dot active layer; 6) Remove the Ag2Te quantum dot solution from the centrifuge tube after step 5), and add a hole transport layer modification solution to immerse the Ag2Te film for modification. After modification, remove the hole transport layer modification solution, add a cleaning solution for treatment, and obtain a device containing a flexible substrate, a Bi2Se3 electron transport layer, an HgTe quantum dot active layer, and an Ag2Te hole transport layer; wherein: the hole transport layer modification solution contains an acetonitrile solution of ethylenedithiol and polyvinylcarbazole; 7) Remove the device obtained in step 6) from the centrifuge tube, and prepare a metal electrode layer on the Ag2Te hole transport layer of the device to obtain the HgTe quantum dot detector.
[0007] Preferably, in step 1), the flexible substrate is a flexible conductive film, specifically one of flexible ITO conductive film, flexible FTO conductive film, flexible graphene conductive film, PET film, and PEN film.
[0008] Preferably, in step 1), the solvent of the Bi2Se3NCs solution is chlorobenzene with a concentration of 0.5~2μg / mL.
[0009] Preferably, in step 1), the centrifugation speed is 5000~7000 rpm and the centrifugation time is 8~12 min.
[0010] Preferably, in step 1), the thickness of the Bi2Se3 film is 40~200nm.
[0011] Preferably, in step 2), the volume concentrations of ethylenedithiol and triethylamine in the electron transport layer modification solution are 4-6% and 0.4-0.6%, respectively.
[0012] Preferably, in step 3), the solvent of the HgTe quantum dot solution is n-octane with a concentration of 40~60 μg / mL.
[0013] Preferably, in step 3), the centrifugation speed is 7000~9000 rpm and the centrifugation time is 8~12 min.
[0014] Preferably, in step 3), the thickness of the HgTe quantum dot film is 400~600nm.
[0015] Preferably, in step 4), the volume concentration of ethylenedithiol in the quantum dot modification solution is 4-6%, and the mass concentration of sodium iodide is 0.4-0.6 wt%.
[0016] Preferably, in step 5), the solvent of the Ag2Te quantum dot solution is n-hexane and n-octane in a volume ratio of (8~10):1, and the concentration is 0.5~2μg / mL.
[0017] Preferably, in step 5), the centrifugation speed is 5000~7000 rpm and the centrifugation time is 8~12 min.
[0018] Preferably, in step 5), the thickness of the Ag2Te film is 40~200nm.
[0019] Preferably, in step 6), the volume concentration of ethylenedithiol in the hole transport layer modification solution is 4-6%, and the concentration of polyvinylcarbazole is 0.4-0.6 wt%.
[0020] Preferably, in steps 2), 4), and 6), the modification is performed by immersion modification, and the immersion modification time is 20~40s.
[0021] Preferably, in steps 2), 4), and 6), the washing and drying process involves adding a cleaning solution as follows: Add a cleaning solution composed of ethanol and ethyl acetate in a volume ratio of (8-10):1 to the centrifuge tube, centrifuge at 400-600 rpm for 2-4 minutes, and repeat the centrifugation washing 2-3 times; then add ethanol solvent as a secondary cleaning solution, centrifuge at 1400-1600 rpm for 2-4 minutes, and repeat the second centrifugation washing 2-3 times; finally, dry at 30-40°C after washing.
[0022] Preferably, in step 7), a metal electrode layer is prepared by vacuum evaporation.
[0023] Secondly, the present invention provides an HgTe quantum dot detector, which is prepared using the aforementioned preparation method.
[0024] Compared with the prior art, one or more of the above technical solutions can achieve at least one of the following beneficial effects: 1) In this invention, the electron transport layer, quantum dot active layer and hole transport layer of HgTe quantum dot detector are prepared by centrifugation. In order to reduce the stress of each thin film, a corresponding modification liquid is designed for each layer material to modify each layer, thereby avoiding the problem of cracks or wrinkles in the thin films of electron transport layer, quantum dot active layer and hole transport layer, and thus improving the overall performance of detector.
[0025] 2) In this invention, the defects in each layer of the electron transport layer, quantum dot active layer and hole transport layer are reduced after modification, and the interfacial contact performance between each layer is further improved. Therefore, the carrier extraction and transport path can be optimized, carrier recombination can be suppressed, and the HgTe quantum dot detector can have higher photoelectric performance and stability. Attached Figure Description
[0026] Figure 1 This is a schematic diagram of the fabrication process of the HgTe quantum dot detector prepared by centrifugation according to the present invention. Detailed Implementation
[0027] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments. Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.
[0028] In a first aspect, the present invention provides a method for fabricating an HgTe quantum dot detector, comprising the following steps: 1) Fix the flexible substrate on the inner wall of the centrifuge tube, add Bi2Se3NCs solution to the centrifuge tube to immerse the flexible substrate, and centrifuge to prepare a Bi2Se3 film on the flexible substrate; 2) Remove the Bi2Se3NCs solution from the centrifuge tube after step 1), and add an electron transport layer modification solution to immerse the Bi2Se3NCs film for modification. After modification, remove the electron transport layer modification solution, add a cleaning solution for treatment, and obtain the Bi2Se3 electron transport layer. The electron transport layer modification solution is an acetonitrile solution containing ethylenedithiol and triethylamine. 3) Add HgTe quantum dot solution to the centrifuge tube treated in step 2) to immerse the Bi2Se3 electron transport layer, centrifuge, and prepare a layer of HgTe quantum dot film on the Bi2Se3 electron transport layer; 4) Remove the HgTe quantum dot solution from the centrifuge tube after step 3), and add quantum dot modification solution to immerse the HgTe quantum dot film for modification. After modification, remove the quantum dot active layer modification solution, add cleaning solution for treatment, and obtain the HgTe quantum dot active layer. The quantum dot modification solution is an acetonitrile solution containing dodecyl mercaptan and sodium iodide. 5) Add Ag2Te quantum dot solution to the centrifuge tube after step 4) to immerse the HgTe quantum dot active layer, centrifuge, and prepare an Ag2Te thin film on the HgTe quantum dot active layer; 6) Remove the Ag2Te quantum dot solution from the centrifuge tube after step 5), and add a hole transport layer modification solution to immerse the Ag2Te film for modification. After modification, remove the hole transport layer modification solution, add a cleaning solution for treatment, and obtain a device containing a flexible substrate, a Bi2Se3 electron transport layer, an HgTe quantum dot active layer, and an Ag2Te hole transport layer; wherein: the hole transport layer modification solution contains an acetonitrile solution of ethylenedithiol and polyvinylcarbazole; 7) Remove the device obtained in step 6) from the centrifuge tube, and prepare a metal electrode layer on the Ag2Te hole transport layer of the device to obtain the HgTe quantum dot detector.
[0029] In the preparation method of the present invention, after modifying the Bi2Se3 electron transport layer with an acetonitrile solution containing ethylenedithiol and triethylamine, the film quality was found to be significantly improved. This may be because the modification solution treatment improved the interfacial contact performance between Bi2Se3 nanocrystals and between the nanocrystals and the flexible conductive film, thereby effectively reducing the overall stress and reducing the generation of wrinkles and microcracks.
[0030] In the preparation method of the present invention, after treating the HgTe quantum dot active layer with an acetonitrile solution containing dodecyl mercaptan and sodium iodide, it was found that the film quality and the contact effect between functional layers were significantly improved. This may be because the treatment with the modification solution improved the interfacial contact performance between HgTe quantum dots and between quantum dots and Bi2Se3 nanocrystals, thereby effectively reducing the overall stress of the functional layer and reducing the generation of wrinkles and microcracks.
[0031] In the preparation method of this invention, after modifying the Ag2Te hole transport layer with an acetonitrile solution containing ethylenedithiol and polyvinylcarbazole, it was found that the film quality and the contact effect between functional layers were significantly improved. This may be because the modification treatment improved the interfacial contact performance between Ag2Te quantum dots and between quantum dots and HgTe quantum dots, thereby effectively reducing the overall stress of the device and reducing the generation of wrinkles and microcracks.
[0032] Research has shown that the Bi2Se3 electron transport layer, HgTe quantum dot active layer, and Ag2Te hole transport layer in this invention can reduce defects in the active layer through the modification of the modification liquid. In addition, the interfacial contact performance of each active layer is greatly improved after the modification liquid treatment, thereby optimizing the carrier extraction and transport path, suppressing carrier recombination, and making the HgTe quantum dot detector have higher photoelectric performance and long-term working stability.
[0033] Preferably, in step 1), the flexible substrate is a flexible conductive film, specifically one of flexible ITO conductive film, flexible FTO conductive film, flexible graphene conductive film, PET film, and PEN film.
[0034] Preferably, in step 1), the solvent of the Bi2Se3NCs solution is chlorobenzene with a concentration of 0.5~2μg / mL.
[0035] Preferably, in step 1), the centrifugation speed is 5000~7000 rpm and the time is 8~12 min.
[0036] Preferably, in step 1), the thickness of the Bi2Se3 film is 40~200nm.
[0037] Preferably, in step 2), the volume concentrations of ethylenedithiol and triethylamine in the electron transport layer modification solution are 4-6% and 0.4-0.6%, respectively.
[0038] Preferably, in step 3), the solvent of the HgTe quantum dot solution is n-octane with a concentration of 40~60 μg / mL.
[0039] Preferably, in step 3), the centrifugation speed is 7000~9000 rpm and the centrifugation time is 8~12 min.
[0040] Preferably, in step 3), the thickness of the HgTe quantum dot film is 400~600nm.
[0041] Preferably, in step 4), the volume concentration of ethylenedithiol in the quantum dot modification solution is 4-6%, and the mass concentration of sodium iodide is 0.4-0.6 wt%.
[0042] Preferably, in step 5), the solvent of the Ag2Te quantum dot solution is n-hexane and n-octane in a volume ratio of (8~10):1, and the concentration is 0.5~2μg / mL.
[0043] Preferably, in step 5), the centrifugation speed is 5000~7000 rpm and the centrifugation time is 8~12 min.
[0044] Preferably, in step 5), the thickness of the Ag2Te film is 40~200nm.
[0045] Preferably, in step 6), the volume concentration of ethylenedithiol in the hole transport layer modification solution is 4-6%, and the concentration of polyvinylcarbazole is 0.4-0.6 wt%.
[0046] Preferably, in steps 2), 4), and 6), the modification is performed by immersion modification, and the immersion modification time is 20~40s.
[0047] Preferably, in steps 2), 4), and 6), the washing and drying process involves adding a cleaning solution as follows: Add a cleaning solution composed of ethanol and ethyl acetate in a volume ratio of (8-10):1 to the centrifuge tube, centrifuge at 400-600 rpm for 2-4 minutes, and repeat the centrifugation washing 2-3 times; then add ethanol solvent as a secondary cleaning solution, centrifuge at 1400-1600 rpm for 2-4 minutes, and repeat the second centrifugation washing 2-3 times; finally, dry at 30-40°C after washing.
[0048] In this invention, centrifugal washing is used to evenly spread ethanol / ethyl acetate and gently clean the surface. Then, high-speed centrifugation is used to thoroughly remove residual modification solution and cleaning agent, avoiding the damage that traditional soaking cleaning may cause to the film.
[0049] Preferably, in step 7), a metal electrode layer is prepared by vacuum evaporation.
[0050] Secondly, the present invention provides an HgTe quantum dot detector, which is prepared using the aforementioned preparation method.
[0051] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.
[0052] Figure 1 This is a schematic diagram of the preparation process of the HgTe quantum dot detector by centrifugation according to the present invention. The specific method can be found in the embodiments.
[0053] Example 1 The HgTe quantum dot detector in this embodiment comprises, from bottom to top: a flexible ITO conductive thin film substrate, a Bi₂Se₃ electron transport layer, an HgTe quantum dot active layer, an Ag₂Te hole transport layer, and an Au electrode layer. The specific fabrication method is as follows: 1) Solution preparation: Bi2Se3NCs were dispersed in chlorobenzene to prepare a Bi2Se3NCs solution with a concentration of 1 μg / mL.
[0054] HgTe quantum dots were dispersed in n-octane to prepare a HgTe quantum dot solution with a concentration of 50 μg / mL.
[0055] Ag2Te quantum dots were dispersed in a mixed solvent of n-hexane and n-octane with a volume ratio of 9:1 to prepare an Ag2Te quantum dot solution with a concentration of 1 μg / mL.
[0056] Ethylene dithiol, triethylamine, and acetonitrile were mixed in a volume ratio of 5:0.5:94.5 to obtain an electron transport layer modified solution.
[0057] Dodecyl mercaptan and acetonitrile were mixed at a volume ratio of 5:95 to obtain a mixed solution. Then, sodium iodide was added to the mixed solution at a mass concentration of 0.5 wt% to obtain a quantum dot modified solution.
[0058] Ethylene dithiol and acetonitrile were mixed at a volume ratio of 5:95 to obtain a mixed solution. Then, polyvinylcarbazole was added to the mixed solution at a mass concentration of 0.5 wt% to obtain a hole transport layer modified solution.
[0059] 2) Fix the flexible ITO conductive film substrate on the inner wall of the centrifuge tube, add Bi2Se3NCs solution to the centrifuge tube to immerse the flexible substrate, and then place it in a centrifuge and centrifuge at 6000 rpm for 10 min to prepare a Bi2Se3 film with a thickness of about 120 nm on the flexible substrate.
[0060] 3) Remove the excess Bi2Se3NCs solution from the centrifuge tube after the treatment in step 2), and add electron transport layer modification solution to the centrifuge tube to immerse the Bi2Se3NCs film. After soaking for 30 seconds, remove the excess electron transport layer modification solution, add cleaning solution for washing and drying to obtain the Bi2Se3 electron transport layer.
[0061] 4) Add HgTe quantum dot solution to the centrifuge tube after step 3) to immerse the Bi2Se3 electron transport layer, and then centrifuge at 8000 rpm for 10 min to prepare an HgTe quantum dot film with a thickness of about 500 nm on the Bi2Se3 electron transport layer.
[0062] 5) Remove the excess HgTe quantum dot solution from the centrifuge tube after step 4), and add quantum dot modification solution to the centrifuge tube to immerse the HgTe quantum dot film. After soaking for 30 seconds, remove the excess quantum dot active layer modification solution, add cleaning solution for washing, and obtain the HgTe quantum dot active layer.
[0063] 6) Add Ag2Te quantum dot solution to the centrifuge tube after step 5) to immerse the HgTe quantum dot active layer, then place it in a centrifuge and centrifuge at 6000 rpm for 10 min to prepare an Ag2Te film with a thickness of about 120 nm on the HgTe quantum dot active layer.
[0064] 7) Remove the excess Ag2Te quantum dot solution from the centrifuge tube after step 6), and add hole transport layer modification solution to the centrifuge tube to immerse the Ag2Te film. After soaking for 30 seconds, remove the excess hole transport layer modification solution, add cleaning solution for washing and drying to obtain an intermediate device. The intermediate device, from bottom to top, includes: a flexible substrate, a Bi2Se3 electron transport layer, an HgTe quantum dot active layer, and an Ag2Te hole transport layer.
[0065] 8) Remove the intermediate device from the centrifuge tube and prepare a metal electrode layer on the Ag2Te hole transport layer to obtain the HgTe quantum dot detector.
[0066] In this embodiment, the specific steps for washing and drying by adding cleaning solution in steps 3), 5), and 7) are as follows: Add a mixed solvent of ethanol and ethyl acetate at a volume ratio of 9:1 to the centrifuge tube, and then centrifuge at 500 rpm for 3 min for washing. Repeat the centrifugal washing twice (for a total of 3 times). Next, add ethanol solvent and centrifuge at 1500 rpm for 3 min for a second centrifugal washing. Repeat the second centrifugal washing twice (for a total of 3 times). After removing excess ethanol, dry at 35°C.
[0067] Comparative Example 1 The process is basically the same as in Example 1, except that the Bi2Se3 film, HgTe quantum dot film, and Ag2Te film are not modified, i.e., steps 3), 5), and 7 are not performed.
[0068] Comparative Example 2 This comparative example includes three parallel comparative examples.
[0069] Comparative Example 2-1: Basically the same as Example 1, except that the Bi2Se3 film is not modified, i.e., step 3 is not performed.
[0070] Comparative Example 2-2: Basically the same as Example 1, except that the HgTe quantum dot film is not modified, i.e., step 5 is not performed.
[0071] Comparative Examples 2-3: Basically the same as Example 1, except that the Ag2Te film is not modified, i.e., step 7 is not performed.
[0072] Comparative Example 3 This comparative example includes three parallel comparative examples.
[0073] Comparative Example 3-1: It is basically the same as Example 1, except that in step 1), ethylenedithiol and acetonitrile are mixed in a volume ratio of 5:95 to obtain an electron transport layer modified solution; that is, triethylamine is not added.
[0074] Comparative Example 3-2: Basically the same as Example 1, except that: dodecyl mercaptan and acetonitrile were mixed in a volume ratio of 5:95 to obtain a quantum dot modified solution, i.e., sodium iodide was not added.
[0075] Comparative Example 3-3: Basically the same as Example 1, except that: ethylenedithiol and acetonitrile were mixed at a volume ratio of 5:95 to obtain a hole transport layer modified solution, i.e., without the addition of polyvinylcarbazole.
[0076] Example 2 The HgTe quantum dot detector in this embodiment comprises, from bottom to top: a flexible PET film substrate layer, a Bi₂Se₃ electron transport layer, an HgTe quantum dot active layer, an Ag₂Te hole transport layer, and an Au electrode layer. The specific fabrication method is as follows: 2) Solution preparation: Bi2Se3NCs were dispersed in chlorobenzene to prepare a Bi2Se3NCs solution with a concentration of 0.5 μg / mL.
[0077] HgTe quantum dots were dispersed in n-octane to prepare an HgTe quantum dot solution with a concentration of 60 μg / mL.
[0078] Ag2Te quantum dots were dispersed in a mixed solvent of n-hexane and n-octane with a volume ratio of 10:1 to prepare an Ag2Te quantum dot solution with a concentration of 2 μg / mL.
[0079] Ethylene dithiol, triethylamine, and acetonitrile were mixed in a volume ratio of 4:0.6:95.4 to obtain an electron transport layer modified solution.
[0080] Dodecyl mercaptan and acetonitrile were mixed at a volume ratio of 4:96 to obtain a mixed solution. Then, sodium iodide was added to the mixed solution at a mass concentration of 0.4 wt% to obtain a quantum dot modified solution.
[0081] Ethylene dithiol and acetonitrile were mixed at a volume ratio of 4:96 to obtain a mixed solution. Then, polyvinylcarbazole was added to the mixed solution at a mass concentration of 0.4 wt% to obtain a hole transport layer modified solution.
[0082] 2) Fix the flexible PET film substrate on the inner wall of the centrifuge tube, add Bi2Se3NCs solution to the centrifuge tube to immerse the flexible substrate, and then place it in a centrifuge and centrifuge at 5000 rpm for 12 min to prepare a Bi2Se3 film with a thickness of about 80 nm on the flexible substrate.
[0083] 3) Remove the excess Bi2Se3NCs solution from the centrifuge tube after step 2), and add electron transport layer modification solution to the centrifuge tube to immerse the Bi2Se3NCs film. After soaking for 40 seconds, remove the excess electron transport layer modification solution, add cleaning solution for washing and drying to obtain the Bi2Se3 electron transport layer.
[0084] 4) Add HgTe quantum dot solution to the centrifuge tube after step 3) to immerse the Bi2Se3 electron transport layer, and then centrifuge at 9000 rpm for 12 min to prepare an HgTe quantum dot film with a thickness of about 600 nm on the Bi2Se3 electron transport layer.
[0085] 5) Remove the excess HgTe quantum dot solution from the centrifuge tube after step 4), and add quantum dot modification solution to the centrifuge tube to immerse the HgTe quantum dot film. After soaking for 40 seconds, remove the excess quantum dot active layer modification solution, add cleaning solution for washing, and obtain the HgTe quantum dot active layer.
[0086] 6) Add Ag2Te quantum dot solution to the centrifuge tube after step 5) to immerse the HgTe quantum dot active layer, then place it in a centrifuge and centrifuge at 5000 rpm for 12 min to prepare an Ag2Te film with a thickness of about 160 nm on the HgTe quantum dot active layer.
[0087] 7) Remove the excess Ag2Te quantum dot solution from the centrifuge tube after step 6), and add hole transport layer modification solution to the centrifuge tube to immerse the Ag2Te film. After soaking for 40 seconds, remove the excess hole transport layer modification solution, add cleaning solution for washing and drying to obtain an intermediate device. The intermediate device, from bottom to top, includes: a flexible substrate, a Bi2Se3 electron transport layer, an HgTe quantum dot active layer, and an Ag2Te hole transport layer.
[0088] 8) Remove the intermediate device from the centrifuge tube and prepare an Au electrode layer on the Ag2Te hole transport layer to obtain the HgTe quantum dot detector.
[0089] In this embodiment, the specific steps for washing and drying by adding cleaning solution in steps 3), 5), and 7) are as follows: Add a mixed solvent of ethanol and ethyl acetate at a volume ratio of 10:1 to the centrifuge tube, then centrifuge at 600 rpm for 2 min for washing, repeating the centrifugation washing twice (for a total of 3 times). Next, add ethanol solvent, centrifuge at 1400 rpm for 4 min for a second centrifugation washing, repeating the second centrifugation washing twice (for a total of 3 times). After removing excess ethanol, dry at 40°C.
[0090] Example 3 The HgTe quantum dot detector in this embodiment comprises, from bottom to top: a flexible PEN thin film substrate, a Bi₂Se₃ electron transport layer, an HgTe quantum dot active layer, an Ag₂Te hole transport layer, and an Au electrode layer. The specific fabrication method is as follows: 3) Solution preparation: Bi2Se3NCs were dispersed in chlorobenzene to prepare a Bi2Se3NCs solution with a concentration of 2 μg / mL.
[0091] HgTe quantum dots were dispersed in n-octane to prepare an HgTe quantum dot solution with a concentration of 40 μg / mL.
[0092] Ag2Te quantum dots were dispersed in a mixed solvent of n-hexane and n-octane with a volume ratio of 8:1 to prepare an Ag2Te quantum dot solution with a concentration of 0.5 μg / mL.
[0093] Ethylene dithiol, triethylamine, and acetonitrile were mixed in a volume ratio of 6:0.4:93.6 to obtain an electron transport layer modified solution.
[0094] Dodecyl mercaptan and acetonitrile were mixed at a volume ratio of 6:94 to obtain a mixed solution. Then, sodium iodide was added to the mixed solution at a mass concentration of 0.6 wt% to obtain a quantum dot modified solution.
[0095] Ethylene dithiol and acetonitrile were mixed at a volume ratio of 6:94 to obtain a mixed solution. Then, polyvinylcarbazole was added to the mixed solution at a mass concentration of 0.6 wt% to obtain a hole transport layer modified solution.
[0096] 2) Fix the flexible PEN film substrate on the inner wall of the centrifuge tube, add Bi2Se3NCs solution to the centrifuge tube to immerse the flexible substrate, and then place it in a centrifuge and centrifuge at 7000 rpm for 8 min to prepare a Bi2Se3 film with a thickness of about 160 nm on the flexible substrate.
[0097] 3) Remove the excess Bi2Se3NCs solution from the centrifuge tube after step 2), and add electron transport layer modification solution to the centrifuge tube to immerse the Bi2Se3NCs film. After soaking for 20 seconds, remove the excess electron transport layer modification solution, add cleaning solution for washing and drying to obtain the Bi2Se3 electron transport layer.
[0098] 4) Add HgTe quantum dot solution to the centrifuge tube after step 3) to immerse the Bi2Se3 electron transport layer, and then centrifuge at 7000 rpm for 8 min to prepare an HgTe quantum dot film with a thickness of about 400 nm on the Bi2Se3 electron transport layer.
[0099] 5) Remove the excess HgTe quantum dot solution from the centrifuge tube after step 4), and add quantum dot modification solution to the centrifuge tube to immerse the HgTe quantum dot film. After soaking for 20 seconds, remove the excess quantum dot active layer modification solution, add cleaning solution for washing, and obtain the HgTe quantum dot active layer.
[0100] 6) Add Ag2Te quantum dot solution to the centrifuge tube after step 5) to immerse the HgTe quantum dot active layer, then place it in a centrifuge and centrifuge at 7000 rpm for 8 min to prepare an Ag2Te film with a thickness of about 80 nm on the HgTe quantum dot active layer.
[0101] 7) Remove the excess Ag2Te quantum dot solution from the centrifuge tube after step 6), and add hole transport layer modification solution to the centrifuge tube to immerse the Ag2Te film. After soaking for 20 seconds, remove the excess hole transport layer modification solution, add cleaning solution for washing and drying to obtain an intermediate device. The intermediate device, from bottom to top, includes: a flexible substrate, a Bi2Se3 electron transport layer, an HgTe quantum dot active layer, and an Ag2Te hole transport layer.
[0102] 8) Remove the intermediate device from the centrifuge tube and prepare an Au electrode layer on the Ag2Te hole transport layer to obtain the HgTe quantum dot detector.
[0103] In this embodiment, the specific steps for washing and drying by adding cleaning solution in steps 3), 5), and 7) are as follows: Add a mixed solvent of ethanol and ethyl acetate at a volume ratio of 8:1 to the centrifuge tube, and then centrifuge at 400 rpm for 4 min for washing. Repeat the centrifugal washing twice (for a total of 3 times). Next, add ethanol solvent and centrifuge at 1600 rpm for 2 min for a second centrifugal washing. Repeat the second centrifugal washing twice (for a total of 3 times). After removing excess ethanol, dry at 30°C.
[0104] The response band, responsivity, response speed, and detectivity of the HgTe quantum dot detectors in Examples 1-3 and Comparative Examples 1-3 were studied, and the results are shown in Table 1.
[0105] Table 1 As can be seen from the data in Table 1, the HgTe quantum dot detector prepared by centrifugation in Comparative Example 1 has lower responsivity, response speed, and detectivity. This may be because the film stress of the Bi2Se3 electron transport layer, HgTe quantum dot active layer, and Ag2Te hole transport layer prepared by centrifugation is relatively high, leading to wrinkles or cracks in each layer, resulting in poor contact between the layers and thus poor detector performance. In Example 1, after preparing each layer of film, corresponding modification solutions were used for modification treatment, and the performance of the prepared HgTe quantum dot detector was significantly improved compared to Comparative Example 1. In Comparative Examples 2-1, 2-2, and 2-3, the Bi2Se3 electron transport layer, HgTe quantum dot active layer, and Ag2Te hole transport layer were not modified, respectively. Their overall performance was improved compared to Comparative Example 1, but significantly lower than that of Example 1. This may be because the electron transport layer, quantum dot active layer, and hole transport layer all have certain stress during the preparation of the film by centrifugation, and therefore, without modification treatment, the detector performance will decrease. In Comparative Examples 3-1, 3-2, and 3-3, the modification solutions for the Bi₂Se₃ electron transport layer, HgTe quantum dot active layer, and Ag₂Te hole transport layer, respectively, contained only thiols. The detectors prepared accordingly showed improved performance compared to Comparative Examples 1 and 2, but not as good as in Example 1. This may be because triethylamine, sodium iodide, and polyvinylcarbazole help to further release the stress in the electron transport layer, quantum dot active layer, and hole transport layer, respectively, thereby improving the overall performance of the device. In Examples 2 and 3, the process parameters were adjusted, resulting in some fluctuation in the overall performance of the prepared detectors, but both exhibited good overall performance.
[0106] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.
Claims
1. A method for fabricating an HgTe quantum dot detector, characterized in that, Includes the following steps: 1) Fix the flexible substrate on the inner wall of the centrifuge tube, add Bi2Se3 NCs solution to the centrifuge tube to immerse the flexible substrate, and centrifuge to prepare a Bi2Se3 film on the flexible substrate; 2) Remove the Bi2Se3 NCs solution from the centrifuge tube after step 1), and add an electron transport layer modification solution to immerse the Bi2Se3 NCs film for modification. After modification, remove the electron transport layer modification solution, add a cleaning solution for treatment, and obtain the Bi2Se3 electron transport layer. The electron transport layer modification solution is an acetonitrile solution containing ethylenedithiol and triethylamine. 3) Add HgTe quantum dot solution to the centrifuge tube treated in step 2) to immerse the Bi2Se3 electron transport layer, centrifuge, and prepare a layer of HgTe quantum dot film on the Bi2Se3 electron transport layer; 4) Remove the HgTe quantum dot solution from the centrifuge tube after step 3), and add quantum dot modification solution to immerse the HgTe quantum dot film for modification. After modification, remove the quantum dot active layer modification solution, add cleaning solution for treatment, and obtain the HgTe quantum dot active layer. The quantum dot modification solution is an acetonitrile solution containing dodecyl mercaptan and sodium iodide. 5) Add Ag2Te quantum dot solution to the centrifuge tube after step 4) to immerse the HgTe quantum dot active layer, centrifuge, and prepare an Ag2Te thin film on the HgTe quantum dot active layer; 6) Remove the Ag2Te quantum dot solution from the centrifuge tube after step 5), and add a hole transport layer modification solution to immerse the Ag2Te film for modification. After modification, remove the hole transport layer modification solution, add a cleaning solution for treatment, and obtain a device containing a flexible substrate, a Bi2Se3 electron transport layer, an HgTe quantum dot active layer, and an Ag2Te hole transport layer; wherein: the hole transport layer modification solution contains an acetonitrile solution of ethylenedithiol and polyvinylcarbazole; 7) Remove the device obtained in step 6) from the centrifuge tube, and prepare a metal electrode layer on the Ag2Te hole transport layer of the device to obtain the HgTe quantum dot detector.
2. The method for fabricating the HgTe quantum dot detector according to claim 1, characterized in that, In step 1), the flexible substrate is a flexible conductive film, specifically one of flexible ITO conductive film, flexible FTO conductive film, flexible graphene conductive film, PET film, and PEN film; The solvent for the Bi2Se3 NCs solution is chlorobenzene, with a concentration of 0.5~2μg / mL; The centrifugation speed is 5000~7000 rpm, and the centrifugation time is 8~12 min; The thickness of the Bi2Se3 thin film is 40~200nm.
3. The method for fabricating the HgTe quantum dot detector according to claim 1, characterized in that, In step 2), the volume concentrations of ethylenedithiol and triethylamine in the electron transport layer modification solution are 4-6% and 0.4-0.6%, respectively.
4. The method for fabricating the HgTe quantum dot detector according to claim 1, characterized in that, In step 3), the solvent for the HgTe quantum dot solution is n-octane, with a concentration of 40~60 μg / mL; The centrifugation speed is 7000~9000 rpm, and the centrifugation time is 8~12 min; The thickness of the HgTe quantum dot film is 400~600 nm.
5. The method for fabricating the HgTe quantum dot detector according to claim 1, characterized in that, In step 4), the volume concentration of dodecyl mercaptan in the quantum dot modification solution is 4-6%, and the mass concentration of sodium iodide is 0.4-0.6 wt%.
6. The method for fabricating the HgTe quantum dot detector according to claim 1, characterized in that, In step 5), the solvent of the Ag2Te quantum dot solution is n-hexane and n-octane in a volume ratio of (8~10):1, and the concentration is 0.5~2μg / mL; The centrifugation speed is 5000~7000 rpm, and the centrifugation time is 8~12 min; The thickness of the Ag2Te thin film is 40~200nm.
7. The method for fabricating the HgTe quantum dot detector according to claim 1, characterized in that, In step 6), the volume concentration of ethylenedithiol in the hole transport layer modification solution is 4-6%, and the concentration of polyvinylcarbazole is 0.4-0.6 wt%.
8. The method for fabricating the HgTe quantum dot detector according to claim 1, characterized in that, In steps 2), 4), and 6), the modification is performed by immersion modification, and the immersion modification time is 20~40s.
9. The method for fabricating the HgTe quantum dot detector according to claim 1, characterized in that, In steps 2), 4), and 6), the specific steps for adding the cleaning solution are as follows: Add a cleaning solution consisting of ethanol and ethyl acetate in a volume ratio of (8~10):1 to the centrifuge tube, centrifuge at 400~600 rpm for 2~4 min to perform centrifugal washing, and repeat the centrifugal washing 2~3 times; then add ethanol as a secondary cleaning solution, centrifuge at 1400~1600 rpm for 2~4 min to perform a second centrifugal washing, and repeat the second centrifugal washing 2~3 times; after washing, dry at 30~40℃.
10. An HgTe quantum dot detector, characterized in that, It is prepared by any of the preparation methods described in claims 1 to 9.