A pixelated scintillation screen based on a silicon-silicon dioxide array (SOA) template and a method of making the same
By introducing Cs5Cu3Cl6I2 single crystals onto a silicon-silica array template, the resolution and crosstalk problems of traditional scintillation films are solved, achieving high-resolution, low-dose X-ray imaging and possessing the potential for large-scale production.
Patent Information
- Application Number
- CN202610319601.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-03-16
- Publication Date
- 2026-06-02
Smart Images
Figure CN122138493A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of X-ray imaging materials technology, specifically to a pixelated scintillator screen with a waveguide structure, its large-scale fabrication method, and an X-ray imaging detector containing the scintillator screen. Background Technology
[0002] X-ray imaging technology, as a non-destructive testing method, has been widely used in medical diagnosis, industrial inspection, and safety screening. Indirect X-ray detectors have become the mainstream application solution due to their lower cost and excellent operational stability. Their core component is a scintillator screen, which converts incident X-rays into visible light, and then converts them into electrical signals through a photodetector.
[0003] Traditional indirect X-ray detectors often employ polycrystalline thick-film scintillators, such as CsI:Tl films or halide nanocrystal-polymer composite films. However, these scintillator films have significant drawbacks: the grain boundaries of polycrystalline domains lead to severe internal light scattering, causing photon lateral diffusion and optical crosstalk, significantly reducing imaging resolution; simultaneously, scattering results in low photon transmission efficiency, limiting the detection capability of low-dose X-rays. To address these issues, researchers have developed structured scintillator arrays, such as 3D-printed plastic scintillator arrays and anodic aluminum oxide (AAO) template-based scintillator arrays. However, the former suffers from high polymer template transmittance and insufficient optical crosstalk suppression, while the latter has excessively thin pore walls (<100 nm), making it prone to evanescent wave penetration, both failing to meet the requirements for high-resolution imaging. Furthermore, the existing structured scintillator fabrication processes are complex, and material compatibility is poor, making it difficult to balance performance, cost, and large-scale production.
[0004] Therefore, developing a novel scintillator structure that combines high spatial resolution, low dose detection sensitivity, excellent stability, and potential for large-scale fabrication is of great significance for promoting the development of X-ray imaging technology. Summary of the Invention
[0005] To overcome the shortcomings of traditional scintillating films in the prior art, such as limited spatial resolution and severe optical crosstalk, the present invention aims to provide a pixelated scintillating screen based on a silicon-silicon dioxide array (SOA) template and its fabrication method. This method can achieve total internal reflection (TIR) for vertical photon transmission, effectively reduce optical crosstalk, suppress lateral scattering and enhance vertical photon transmission, and the fabrication process has high scalability, which can flexibly construct scintillator arrays with customized pixel sizes and layouts.
[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0007] This invention proposes a silicon-silicon dioxide array (SOA) structure that combines scalability and material compatibility, and can integrate multiple scintillators. High-quality Cs5Cu3Cl6I2 single crystals are introduced into the pores covered by SiO2 through a vacuum-assisted infiltration process, achieving excellent crystallinity and high filling density.
[0008] The synthesis of the Cs5Cu3Cl6I2 single crystal is specifically as follows: under a nitrogen atmosphere, CsCl, CuI and CuCl are dissolved in a mixed solution of 1.5 mL DMSO and 0.75 mL HCOOH in a ratio of 1:0.4:0.2.
[0009] Preferably, the dissolution temperature is 130°C; the solution is cooled to 70°C at a rate of 20°C every 3 hours, and then held at 70°C for an additional 8 hours to promote crystal growth.
[0010] Preferably, the crystals are washed with isopropanol, dried under vacuum, and then collected.
[0011] The Cs5Cu3Cl6I2 thin film was prepared by dissolving 0.4g of polymethyl methacrylate (PMMA) in 1mL of toluene.
[0012] Preferably, the mixture is continuously stirred at 100°C until completely dissolved, then cooled and maintained at 60°C.
[0013] Meanwhile, the Cs5Cu3Cl6I2 single crystal was thoroughly ground in a quartz mortar for about 20 minutes to obtain a uniform fine powder material.
[0014] Subsequently, 0.1 g of the obtained Cs5Cu3Cl6I2 crystalline powder was added to the PMMA solution, and stirring was continued for 30 minutes to ensure uniform dispersion.
[0015] Finally, the resulting mixture was poured into a circular mold (diameter: 2cm), and the solvent was allowed to evaporate naturally in air at room temperature for 12 hours.
[0016] The preparation of the silicon-silicon dioxide array (SOA) template specifically involves spin-coating AZ4620 photoresist onto a cleaned silicon wafer and then pre-baking it.
[0017] Subsequently, ultraviolet exposure technology (MA6 / BA6) was used to expose the template and transfer the array pattern onto a double-sided polished p-type (100) silicon substrate with a resistivity of about 1~20 Ω・cm.
[0018] The photoresist in the exposed areas is removed using AZ400K developer, followed by a sufficient post-baking time to form a photoresist mask with an array pattern.
[0019] Next, the silicon substrate is etched using an inductively coupled plasma (ICP) etching process with a balanced mixture of SF6 and Ar gases.
[0020] After etching, the silicon wafer is ultrasonically cleaned with acetone and deionized water, and then dried to finally obtain a silicon template with an array pattern.
[0021] Preferably, the silicon template is placed in a tube furnace at a temperature of 1100°C for 12 hours to ensure that a sufficiently thick SiO2 total internal reflection layer is grown on the surface of the micropores; after the furnace temperature is cooled to room temperature, the silicon template is removed to obtain a silicon array template with a total internal reflection layer.
[0022] The Cs5Cu3Cl6I2-SOA screen was prepared using a vacuum-assisted permeation method, specifically by uniformly placing Cs5Cu3Cl6I2 powder on an SOA template and then placing it in an open quartz boat.
[0023] The quartz boat is placed in a tube furnace and heated under vacuum at 350°C for 10 minutes to ensure that the crystals are completely melted.
[0024] Argon gas is introduced, and the molten material is forced into the array holes by the pressure difference.
[0025] After naturally cooling to room temperature, the sample was removed from the tube furnace and polished to obtain a Cs5Cu3Cl6I2-SOA screen.
[0026] Compared with the prior art, the beneficial effects of the present invention are:
[0027] This invention realizes a pixelated scintillator screen of Cs5Cu3Cl6I2 based on a silicon-silicon dioxide array (SOA) template, solving the spatial resolution limitations and severe optical crosstalk problems commonly found in traditional scintillator films. Through a negative pressure infiltration method, Cs5Cu3Cl6I2 is uniformly filled and recrystallized within the template microchannels to form a high-quality crystalline structure. The low-refractive-index SiO2 layer achieves total internal reflection, while the Si matrix absorbs unguided photons, together forming a pixelated structure with waveguide capabilities. This architecture effectively constrains the lateral diffusion of scintillator photons while enhancing longitudinal photon transmission. The Cs5Cu3Cl6I2-SOA screen synthesized in this invention achieves a spatial resolution of (20.10 lp·mm²). -1 ), photoresponse and ultra-low dose detection capability (as low as 35 nGy·s) -1 In terms of both intrinsic luminescence and optical guidance properties of the optimized array structure, this invention outperforms traditional thin-film counterparts. Attached Figure Description
[0028] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0029] Figure 1 Schematic diagram of SOA flickering screen photon transmission mechanism Figure 2 Spatial resolution compared to traditional Cs5Cu3Cl6I2 thin films and Cs5Cu3Cl6I2-SOA screens Figure 3 Chip Imaging Comparison Detailed Implementation
[0030] 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.
[0031] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.
[0032] Example 1: Synthesis of Cs5Cu3Cl6I2 single crystal (1) Raw material preparation Weigh CsCl, CuI, and CuCl precisely in a molar ratio of 1:0.4:0.2, where CsCl is 1 mmol (168.4 mg), CuI is 0.4 mmol (76.18 mg), and CuCl is 0.2 mmol (19.8 mg). Measure 1.5 mL of dimethyl sulfoxide (DMSO) and 0.75 mL of formic acid (HCOOH) and mix them thoroughly as the reaction solvent.
[0033] (2) Synthesis process Weighed CsCl, CuI, and CuCl were added to the above mixed solvent. Under nitrogen atmosphere protection, the system temperature was raised to 130°C and stirred until the raw materials were completely dissolved. Then, the temperature was slowly cooled to 70°C at a rate of 20°C every 3 hours and maintained at this temperature for 8 hours to promote crystal growth. After the crystal growth was completed, the product was washed with isopropanol to remove residual solvent and impurities. Then, the washed crystal was dried in a vacuum environment. After drying, Cs5Cu3Cl6I2 single crystals were collected.
[0034] Example 2: Preparation of Cs5Cu3Cl6I2 thin films (1) Preparation of PMMA solution Weigh 0.4 g of polymethyl methacrylate (PMMA), add it to 1 mL of toluene solvent, raise the temperature of the system to 100 °C, and continue stirring until the PMMA is completely dissolved. Then cool it to 60 °C and maintain that temperature.
[0035] (2) Preparation of Cs5Cu3Cl6I2 fine powder Take the Cs5Cu3Cl6I2 single crystal synthesized in Example 1, put it into a quartz mortar, and grind it thoroughly for 20 minutes to obtain uniformly dispersed Cs5Cu3Cl6I2 crystalline fine powder.
[0036] (3) Mixing and molding Weigh 0.1g of Cs5Cu3Cl6I2 fine powder and add it to the above-mentioned PMMA solution at 60℃. Continue stirring for 30 minutes to ensure that the Cs5Cu3Cl6I2 fine powder is uniformly dispersed in the PMMA solution. Cast the uniformly dispersed mixture into a circular mold with a diameter of 2cm. Place the mold in room temperature air and allow the toluene solvent to evaporate naturally for 12 hours to finally obtain a Cs5Cu3Cl6I2 film.
[0037] Example 3: Fabrication of a silicon-silicon dioxide array (SOA) template (1) Silicon wafer pretreatment Select double-sided polished p-type (100) silicon wafers with resistivity of 1~20Ω・cm, and ultrasonically clean the silicon wafers with acetone and deionized water in sequence to remove surface oil and impurities. After cleaning, dry them for later use.
[0038] (2) Photoresist coating and pre-baking After cleaning and drying, the silicon wafer is placed on a spin coater and AZ4620 photoresist is evenly spin-coated. After spin coating, a pre-baking process is performed to enhance the adhesion between the photoresist and the silicon wafer surface.
[0039] (3) Ultraviolet exposure and development Using MA6 / BA6 UV exposure technology, the preset array pattern is transferred onto a silicon wafer coated with photoresist. After exposure, the silicon wafer is immersed in AZ400K developer to remove the photoresist in the exposed areas, leaving the unexposed areas to form the photoresist mask for the array pattern. Then, sufficient post-baking is performed to cure the photoresist mask.
[0040] (4) ICP etching A silicon wafer with a photoresist mask is placed in an inductively coupled plasma (ICP) etching apparatus, and a balanced mixture of SF6 and Ar gases is introduced as the etching gas to etch the silicon substrate and form an array of microporous structures.
[0041] (5) Silicon template cleaning and thermal oxidation After etching, the silicon wafer is ultrasonically cleaned sequentially with acetone and deionized water to remove residual photoresist and etching products. After cleaning, it is dried to obtain a silicon template with an array pattern. The dried silicon template is placed in a tube furnace, and the furnace temperature is raised to 1100°C and maintained at this temperature for 12 hours for thermal oxidation treatment, so that a sufficiently thick SiO2 total internal reflection layer is grown on the surface of the micropores of the silicon template. After thermal oxidation, the temperature of the tube furnace is allowed to cool naturally to room temperature, and the silicon template is removed to obtain a silicon-silicon dioxide array (SOA) template with a total internal reflection layer.
[0042] Example 4: Preparation of Cs5Cu3Cl6I2-SOA screen (1) Raw material laying The Cs5Cu3Cl6I2 single crystal synthesized in Example 1 was ground into fine powder and then evenly spread on the surface of the SOA template prepared in Example 3. The SOA template with powder was then placed in an open quartz boat.
[0043] (2) Vacuum heating and melting The quartz boat was placed in the tube furnace, the furnace door was closed and a vacuum was drawn to create a vacuum environment inside the furnace; then the furnace temperature was raised to 350°C and maintained for 10 minutes to ensure that the Cs5Cu3Cl6I2 powder was completely melted.
[0044] (3) Penetration filling and post-treatment Argon gas is introduced into the tube furnace, and the molten Cs5Cu3Cl6I2 is pressed into the array micropores of the SOA template by utilizing the pressure difference between the inside of the furnace and the outside. Heating is stopped, and the tube furnace is allowed to cool naturally to room temperature. After the sample has cooled, it is taken out of the furnace, and the surface of the sample is polished to remove excess material, finally obtaining the Cs5Cu3Cl6I2-SOA pixelated scintillation screen.
[0045] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0046] 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 pixelated flickering screen, characterized in that, The invention includes a silicon-silicon dioxide array template comprising a silicon substrate and a plurality of micropores formed on and defined thereon on the silicon substrate, wherein the inner surface of the micropores has a silicon dioxide total internal reflection layer; and a crystalline scintillator material filled within the micropores, wherein the scintillator material is Cs5Cu3Cl6I2.
2. The pixelated flickering screen according to claim 1, characterized in that, The silicon substrate is a double-sided polished p-type (100) silicon substrate with a resistivity of 1~20 Ω·cm.
3. The pixelated flickering screen according to claim 1 or 2, characterized in that, The scintillation screen has a spatial resolution of ≥20.10 lp·mm⁻¹ for X-rays and a minimum detectable dose of ≤35 nGy·s⁻¹.
4. A method for preparing a pixelated flickering screen as described in any one of claims 1-3, characterized in that, Includes the following steps: (1) Synthesis of Cs5Cu3Cl6I2 single crystal: Under nitrogen atmosphere, CsCl, CuI and CuCl were dissolved in a mixed solution of dimethyl sulfoxide and formic acid in a molar ratio of 1:0.4:0.2 and heated to 130℃ to dissolve completely; then the temperature was programmed to decrease to 70℃ at a rate of 20℃ every 3 hours and held for 8 hours to allow crystal precipitation; after separation, washing and drying, Cs5Cu3Cl6I2 single crystal was obtained; (2) Fabrication of silicon-silicon dioxide array template: a. Photoresist is spin-coated onto the cleaned silicon substrate, and after exposure and development, a photoresist mask with an array pattern is formed; b. Using the photoresist mask as a protective layer, an inductively coupled plasma etching process is used to etch the silicon substrate to form a micro-hole array; c. Remove residual photoresist, clean and dry to obtain a silicon template; d. The silicon template is placed in an oxidizing atmosphere and subjected to thermal oxidation treatment to grow a silicon dioxide total internal reflection layer on the inner wall of the micropores, thereby obtaining a silicon-silicon dioxide array template; (3) Fabrication of Cs5Cu3Cl6I2-silicon-silicon dioxide array scintillator: a. Grind the Cs5Cu3Cl6I2 single crystal obtained in step (1) into powder and place it on the upper surface of the silicon-silicon dioxide array template obtained in step (2); b. Place the template loaded with powder in a vacuum environment and heat it to 350℃ to melt Cs5Cu3Cl6I2; c. Release the vacuum, introduce inert gas, and use the gas pressure difference to force the molten Cs5Cu3Cl6I2 into the micropores; d. Allow to cool naturally to room temperature, allowing Cs5Cu3Cl6I2 to recrystallize within the micropores; e. Polish the template surface to remove excess material and obtain a Cs5Cu3Cl6I2-silicon-silicon dioxide array scintillator screen.
5. The preparation method according to claim 4, characterized in that, In step (1), the volume ratio of dimethyl sulfoxide to formic acid in the mixed solution of dimethyl sulfoxide and formic acid is 2:
1.
6. The preparation method according to claim 4, characterized in that, In step (2), step d, the temperature of the thermal oxidation treatment is 1100℃ and the time is 12 hours.
7. The preparation method according to claim 4, characterized in that, In step (3)b, the vacuum heating time is 10 minutes.