X-ray detector and functional unit and method of manufacturing thereof
By modifying the surface of the circuit substrate to reduce the nucleation barrier, heterogeneous nucleation and growth of perovskite on the circuit substrate are achieved, solving the problems of expensive equipment and non-uniform conductivity in existing technologies, and realizing the direct growth and uniform attachment of perovskite crystals.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- EZHOU INST OF IND TECH HUAZHONG UNIV OF SCI & TECH
- Filing Date
- 2022-12-30
- Publication Date
- 2026-05-12
AI Technical Summary
Existing technologies for fabricating X-ray detectors using single-crystal materials require expensive bonding machines and ACF adhesives, which result in problems such as uneven distribution of conductive metal particles and inconsistent interfacial conductivity.
By modifying the surface of the circuit substrate, the nucleation barrier of perovskite on the substrate surface is reduced to be smaller than that of the three-dimensional nucleation barrier in solution, thereby enabling heterogeneous nucleation and growth of perovskite on the circuit substrate and avoiding the use of bonding processes.
This method enables the direct growth of perovskite crystals on circuit substrates, avoiding the use of expensive bonding machines and ACF adhesive, and solving the problems of uneven conductivity and dead pixels.
Smart Images
Figure CN115988936B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of semiconductor photodetector technology, and in particular to an X-ray detector, its functional unit, and its fabrication method. Background Technology
[0002] Current X-ray imaging technology can be divided into two types: indirect imaging and direct imaging. Indirect detection imaging utilizes a scintillator that emits randomly emitted visible light after being irradiated by X-rays, which is then detected and imaged using a photodetector. Direct detection imaging, on the other hand, utilizes semiconductor materials that absorb high-energy X-rays, generating electron-hole pairs. Under the influence of an applied electric field, these pairs move directionally and are collected by an external circuit to achieve signal detection. Direct detection imaging does not have the problem of light scattering between different pixels, and theoretically has a significant advantage in resolution.
[0003] Currently, the materials used in direct imaging detectors fall into three categories: single-crystal materials, polycrystalline materials, and amorphous materials. When fabricating direct imaging detectors using single-crystal materials, perovskite crystals are typically prepared first using solution or melt methods, and then bonded to the circuit substrate. The bonding process requires expensive bonding machines and ACF adhesive. The conductive metal particles within the ACF adhesive may be unevenly distributed, posing a risk of dead pixels and inconsistent conductivity at the interface between different pixels and the crystal. Summary of the Invention
[0004] This application provides an X-ray detector, its functional unit, and a fabrication method, offering a novel approach to attaching perovskite crystals onto a circuit substrate, thereby avoiding the use of bonding processes.
[0005] In a first aspect, this application provides a method for preparing a functional unit, the method comprising:
[0006] The surface of the circuit substrate is modified so that the nucleation barrier of perovskite on the surface of the circuit substrate is less than the three-dimensional nucleation barrier of perovskite in solution, thus obtaining a modified circuit substrate.
[0007] Perovskite crystals are grown on the surface of the modified circuit substrate to obtain functional units.
[0008] As an optional implementation, the surface of the circuit substrate is modified so that the nucleation barrier of perovskite on the circuit substrate surface is less than the three-dimensional nucleation barrier of perovskite in solution, thereby obtaining a modified circuit substrate. Specifically, this includes:
[0009] A modified layer is formed on the surface of the circuit substrate to make the nucleation barrier of perovskite on the circuit substrate surface smaller than the three-dimensional nucleation barrier of perovskite in solution, thereby obtaining a modified circuit substrate.
[0010] As an optional implementation, the method of forming the modified layer includes: coating the surface of the circuit substrate with a modified material, followed by annealing; and / or
[0011] The method of forming the modified layer includes: immersing the circuit substrate in the modified material; and / or
[0012] The modified material is hydrophobic; and / or
[0013] The modified material has the ability to coordinate with perovskite.
[0014] As an optional implementation, the modified material includes at least one of PTAA and APTES.
[0015] As an optional implementation, the annealing temperature is 90-110°C; and / or
[0016] The annealing time is 5-15 minutes.
[0017] As an optional implementation, the step of growing perovskite crystals on the surface of the modified circuit substrate to obtain functional units specifically includes:
[0018] The modified circuit substrate is immersed in a perovskite crystal growth solution to grow perovskite crystals on the surface of the modified circuit substrate, thereby obtaining a functional unit.
[0019] As an optional implementation, the perovskite crystal growth solution comprises at least one type of perovskite; the chemical formula of the perovskite is ABX3, where A is Cs. + MA + or FA + B is Pb 2+ or Sn 2+ X is Cl - ,Br - Or I - .
[0020] As an optional implementation, the temperature of the perovskite crystal growth solution in the perovskite crystal growth process is 45-55°C; and / or
[0021] The heating rate of the perovskite crystal growth solution in the perovskite crystal growth process is 0.5-1.5℃ / h.
[0022] Secondly, this application provides a functional unit, which is prepared using the method described in the first aspect.
[0023] Thirdly, this application provides an X-ray detector, which includes the functional units described in the second aspect.
[0024] The technical solutions provided in this application have the following advantages compared with the prior art:
[0025] The method provided in this application provides a new approach for attaching perovskite crystals to a circuit substrate. By reducing the nucleation barrier of perovskite on the surface of the circuit substrate and making it smaller than the three-dimensional nucleation barrier of perovskite in solution, heterogeneous nucleation and growth of perovskite on the circuit substrate are achieved. Furthermore, by directly growing perovskite crystals in situ on the circuit substrate, the bonding process for attaching perovskite crystals is avoided, thus avoiding the use of expensive bonding machines and ACF adhesive. This overcomes the problems of uneven distribution of conductive metal particles inside the ACF adhesive, which can lead to defects and uneven conductivity at the interface between different pixels and crystals. Attached Figure Description
[0026] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.
[0027] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the 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.
[0028] Figure 1 A flowchart illustrating the method provided in an embodiment of this application. Detailed Implementation
[0029] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0030] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.
[0031] Currently, when fabricating direct imaging detectors using single-crystal materials, perovskite crystals are typically prepared first using solution or melt methods, and then bonded to a circuit substrate. The bonding process requires expensive bonding machines and ACF adhesive. The conductive metal particles within the ACF adhesive may be unevenly distributed, posing a risk of defective pixels and inconsistent conductivity at the interface between different pixels and the crystal.
[0032] The applicant intends to provide a novel approach to attach crystals to circuit substrates, avoiding the use of bonding processes to attach perovskite crystals, thereby avoiding the use of expensive bonding machines and ACF adhesives. This overcomes the problems of uneven distribution of conductive metal particles inside the ACF adhesive, which can lead to dead pixels and uneven conductivity at the interface between different pixels and crystals.
[0033] The applicant attempted to achieve perovskite crystal adhesion to a circuit substrate by directly growing perovskite crystals on the substrate. The applicant discovered that the key to achieving direct perovskite crystal growth on the circuit substrate lies in realizing heterogeneous nucleation and growth of perovskite on the circuit substrate. Heterogeneous nucleation involves disrupting the solvent-circuit interface to form a perovskite-circuit interface. The key to achieving heterogeneous nucleation and growth of perovskite on the circuit substrate is to lower the nucleation barrier of perovskite on the substrate surface to be lower than the three-dimensional nucleation barrier of perovskite in solution. Modifying the circuit surface can effectively reduce the nucleation barrier of perovskite on the substrate surface.
[0034] like Figure 1 As shown in the figure, this application provides a method for preparing a functional unit, the method comprising:
[0035] S1. Modify the surface of the circuit substrate so that the nucleation barrier of perovskite on the surface of the circuit substrate is less than the three-dimensional nucleation barrier of perovskite in solution, thereby obtaining a modified circuit substrate.
[0036] In some embodiments, the surface of the circuit substrate is modified so that the nucleation barrier of perovskite on the surface of the circuit substrate is less than the three-dimensional nucleation barrier of perovskite in solution, thereby obtaining a modified circuit substrate, specifically including:
[0037] A modified layer is formed on the surface of the circuit substrate to make the nucleation barrier of perovskite on the circuit substrate surface smaller than the three-dimensional nucleation barrier of perovskite in solution, thereby obtaining a modified circuit substrate.
[0038] The applicant discovered that hydrophobic molecules can lower the interfacial free energy between the solvent and the circuit, making it easier to break down. Molecules with coordination ability with perovskite can lower the perovskite-circuit interfacial free energy, making it easier to form. The combination of these two factors effectively reduces the nucleation barrier of perovskite on the substrate surface, making it lower than the three-dimensional nucleation barrier of perovskite in solution; furthermore, the modified material is hydrophobic; and the modified material has the ability to coordinate with perovskite.
[0039] In some embodiments, the modified layer may be formed by coating the surface of the circuit substrate with a modified material and then annealing it.
[0040] Furthermore, the modifying material can be selected from PTAA. PTAA stands for Poly[bis(4-phenyl)(2,4,6-triMethylphenyl)aMine]. It should be noted that the above is only an example of a modifying material that can make the nucleation barrier of perovskite on the circuit substrate surface lower than the three-dimensional nucleation barrier of perovskite in solution, and is not intended to limit the present solution. In other embodiments, those skilled in the art can select the modifying material according to actual needs, as long as it can reduce the nucleation barrier of perovskite on the substrate surface and make it lower than the three-dimensional nucleation barrier of perovskite in solution.
[0041] Furthermore, the annealing temperature is 90-110℃, including but not limited to 90℃, 95℃, 100℃, 105℃ and 110℃; the annealing time is 5-15min, including but not limited to 5min, 7min, 10min, 13min and 15min. Those skilled in the art can select the annealing temperature and annealing time according to actual needs.
[0042] In some embodiments, forming the modified layer includes immersing the circuit substrate in a modified material.
[0043] Furthermore, the modified material can be selected from APTES, which stands for aminosilane. It should be noted that the above is only an example of a modified material that can make the nucleation barrier of perovskite on the circuit substrate surface smaller than the three-dimensional nucleation barrier of perovskite in solution, and is not intended to limit the present solution. In other embodiments, those skilled in the art can select the modified material according to actual needs, as long as it can reduce the nucleation barrier of perovskite on the substrate surface and make it smaller than the three-dimensional nucleation barrier of perovskite in solution.
[0044] S2. Perovskite crystals are grown on the surface of the modified circuit substrate to obtain functional units.
[0045] In some embodiments, the growth of perovskite crystals on the surface of the modified circuit substrate to obtain a functional unit specifically includes:
[0046] The modified circuit substrate is immersed in a perovskite crystal growth solution to grow perovskite crystals on the surface of the modified circuit substrate, thereby obtaining a functional unit.
[0047] Furthermore, the perovskite crystal growth solution comprises at least one type of perovskite; the chemical formula of the perovskite is ABX3, where A is Cs. + MA + or FA + B is Pb 2+ or Sn 2+ X is Cl- ,Br - Or I - Examples include FAPbBr3 and MAPbI3, which will not be listed here.
[0048] In some embodiments, the temperature of the perovskite crystal growth solution in the perovskite crystal growth process is 45-55°C; the heating rate of the perovskite crystal growth solution in the perovskite crystal growth process is 0.5-1.5°C / h.
[0049] The above design provides a new approach for attaching perovskite crystals to circuit substrates. By lowering the nucleation barrier of perovskite on the circuit substrate surface to be less than the three-dimensional nucleation barrier of perovskite in solution, heterogeneous nucleation and growth of perovskite on the circuit substrate are achieved. This allows for direct in-situ growth of perovskite crystals on the circuit substrate, avoiding the use of bonding processes for perovskite crystal attachment. Consequently, it avoids the use of expensive bonding machines and ACF adhesives, and overcomes the problems of uneven distribution of conductive metal particles within the ACF adhesive, which can lead to defects and inconsistent conductivity at the interface between different pixels and crystals.
[0050] Based on a general inventive concept, embodiments of this application also provide functional units, which are prepared using the method described above.
[0051] This functional unit is implemented based on the above method. The specific steps of the method can be referred to the above embodiments. Since the functional unit adopts some or all of the technical solutions of the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated here.
[0052] Based on a general inventive concept, an X-ray detector is provided, which includes the functional units provided above.
[0053] The X-ray detector is implemented based on the above-mentioned functional unit. The specific limitations of the functional unit can be referred to the above embodiments. Since the X-ray detector adopts some or all of the technical solutions of the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated here.
[0054] The present application is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards. If there is no corresponding national standard, then general international standards, conventional conditions, or conditions recommended by the manufacturer are followed.
[0055] Example 1
[0056] A method for fabricating a functional unit, the method comprising:
[0057] Step 1: Prepare a 2 mg / ml PTAA chlorobenzene solution.
[0058] Step 2: Add the above solution to the circuit substrate until it is completely covered, and spin coat at a speed of 3000 rpm.
[0059] Step 3: Anneal the circuit after spin coating with PTAA at 100℃ for 10 minutes.
[0060] Step 4: Prepare a 1.27 mol / L FAPbBr3 solution using N,N-dimethylformamide and γ-butyrolactone in a 1:1 ratio as a mixed solvent.
[0061] Step 5: Immerse the circuit substrate obtained in step 3 in the solution obtained in step 4, and place it in a sealed container.
[0062] Step 6: Heat the container containing the FAPbBr3 solution and circuit board from step 5 from 38°C to 50°C at a rate of 1°C / h.
[0063] Step 7: Remove the circuit board with the crystal attached, which is the functional unit.
[0064] Example 2
[0065] A method for fabricating a functional unit, the method comprising:
[0066] Step 1: Prepare a chlorobenzene solution of APTES at a ratio of 1:20.
[0067] Step 2: Soak the circuit board in the above solution for 3 hours, then take out the circuit board and soak and clean it with ethanol.
[0068] Step 3: Prepare a 1.27 mol / L FAPbBr3 solution using N,N-dimethylformamide and γ-butyrolactone in a 1:1 ratio as a mixed solvent.
[0069] Step 4: Immerse the circuit substrate obtained in step 2 in the solution obtained in step 3, and place it in a sealed container.
[0070] Step 5: Heat the container containing the FAPbBr3 solution and circuit board from step 4 from 38°C to 50°C at a rate of 1°C / h.
[0071] Step 6: Remove the circuit board with the crystal attached, which is the functional unit.
[0072] As can be seen from the table above, the method provided in the embodiments of this application for preparing functional units can avoid the use of ACF adhesive, thereby improving the problem that the conductive metal particles inside the ACF adhesive may be unevenly distributed, resulting in bad pixels and uneven conductivity at the interface between different pixels and crystals.
[0073] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.
[0074] In this application, unless otherwise stated, directional terms such as "upper" and "lower" specifically refer to the drawing directions in the accompanying drawings. Furthermore, in the description of this application, terms such as "comprising" and "including" mean "including but not limited to." In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this document, "and / or" describes the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. In this document, "at least one" means one or more, and "more than one" means two or more. "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c" or "at least one of a, b, and c" can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be a single or multiple.
[0075] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. 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 application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.
Claims
1. A method for fabricating an X-ray detector, characterized in that, The method includes: A modified layer is formed on the surface of the circuit substrate so that the nucleation barrier of perovskite on the surface of the circuit substrate is less than the three-dimensional nucleation barrier of perovskite in solution, thereby obtaining a modified circuit substrate. The modified circuit substrate is immersed in a perovskite crystal growth solution to grow perovskite crystals on the surface of the modified circuit substrate, thereby obtaining an X-ray detector. The perovskite crystal growth solution is a 1.27 mol / L FAPbBr3 solution prepared with N,N-dimethylformamide and γ-butyrolactone in a 1:1 mixture as the solvent. The method of forming the modified layer includes: coating the surface of the circuit substrate with a modified material and then annealing it; The modified material includes at least one of PTAA and APTES; the annealing temperature is 90-110℃; the annealing time is 5-15 min; The temperature of the perovskite crystal growth solution in the perovskite crystal growth process is 45-55℃; the heating rate of the perovskite crystal growth solution in the perovskite crystal growth process is 0.5-1.5℃ / h. The method enables in-situ formation of perovskite crystals on a circuit substrate through heterogeneous nucleation and growth, without the need for subsequent bonding processes.
2. The method for preparing an X-ray detector according to claim 1, characterized in that, The method of forming the modified layer includes: immersing the circuit substrate in the modified material; and / or The modified material is hydrophobic; and / or The modified material has the ability to coordinate with perovskite.
3. An X-ray detector, characterized in that, The X-ray detector is prepared using the X-ray detector preparation method according to any one of claims 1 to 2.