A scintillator ink, a scintillator film and their applications

Abstract

The present invention belongs to the technical field of X-ray excitation imaging, and specifically relates to a scintillator ink, a scintillator film and their applications. The scintillator ink is obtained by uniformly dispersing a material Eu-TiOCs, which has good solution dispersibility and high X-ray excitation luminescence performance, in methanol and then doping it into polyvinyl alcohol (PVA) to obtain a scintillator ink with a certain viscosity. After the scintillator ink is coated on a substrate and dried, a flexible scintillator film can be obtained. This scintillator film exhibits good flexibility, transparency and uniformity, can be prepared in large areas, and can achieve high-resolution X-ray imaging of planar and non-planar objects, with a spatial resolution of up to about 13 lp / mm.

Description

Technical Field

[0001] The present invention belongs to the technical field of X-ray excitation imaging, and particularly relates to a scintillator ink, a scintillator film and their applications. Background Art

[0002] In recent decades, the development of scintillators with high efficiency in converting X-ray energy into visible light has been an urgent need in many fields such as industrial non-destructive testing, security inspection, and medical diagnosis. Traditional single-crystal scintillators such as CsI:Tl, Gd2O2S:Ce, Bi4Ge3O 12 , PbWO4 and YAlO3:Ce have severely hindered their further applications due to limitations such as their inherent brittleness, demanding growth conditions, sensitivity to moisture, and complex preparation processes. Therefore, the development of new scintillators has become a research hotspot in recent years, such as metal halide perovskite nanocrystals, lanthanide organic scintillators, lanthanide-doped nanocrystals, cuprous halide complexes, organic scintillators, etc. However, these scintillator materials have problems such as element toxicity, poor environmental stability, or low luminescence efficiency. Achieving a common improvement in the light yield, stability, environmental friendliness of the scintillator, and the uniformity and flexibility of the scintillator screen is an important challenge faced by this research field.

[0003] Referring to the published literature Kang Z, Zhang Y, Menkara H, et al. CdTe quantum dots and polymer nanocomposites for x-ray scintillation and imaging[J]. Applied Physics Letters, 2011, 98(18): 620. DOI: 10.1063 / 1.3589366., a nanoscale scintillator CdTe quantum dot with a smaller particle size is disclosed, which can reduce the scattering of visible light and thus improve the spatial resolution. Its resolution can reach 5 lp / mm, nearly twice that of the traditional scintillator screen such as Gd2O2S:Tb with a resolution of 2.8 lp / mm. However, there is still a large room for improvement for X imaging applications with higher resolution requirements, such as the X-ray imaging needs of chips. Moreover, the low luminescence efficiency of CdTe quantum dots under X-ray irradiation, their toxicity to organisms, and the demanding synthesis conditions limit the application of CdTe quantum dots in the fabrication of scintillator films.

[0004] Rare-earth-titanium-oxygen clusters (Ln-TiOCs) are a class of complex cage-like molecular structures composed of lanthanide ions and polyoxotitanic acid units. The rigid cage-like titanium-oxygen cluster framework can effectively weaken the non-radiative OH- stretching vibration. The organic ligands provide appropriate energy levels to receive secondary electrons generated by X-ray irradiated heavy elements and sensitize rare-earth ions to achieve efficient X-ray excited luminescence. Therefore, rare-earth-titanium-oxygen clusters have great potential as very promising X-ray scintillators.

[0005] However, there is no research report on the design and synthesis of rare-earth-titanium-oxygen clusters with excellent X-ray excited luminescence and structural stability. The main reasons are as follows: The alcohol or carboxylic acid ligands commonly used in the synthesis of rare-earth-titanium-oxygen clusters usually have low X-ray absorption coefficients. The binding of lanthanide(III) ions to the clusters usually involves coordination with small molecules such as water and alcohol molecules, resulting in fluorescence quenching caused by non-radiative OH- stretching vibration. In addition, it has been found that due to the presence of hydrolyzable alkoxy bridges in rare-earth-titanium-oxygen clusters, the structure of rare-earth-titanium-oxygen clusters is sensitive to temperature and humidity. Therefore, the controllable synthesis of stable rare-earth-titanium-oxygen clusters and the precise regulation of the energy transfer efficiency between the X-ray absorption center and the luminescence center are of great significance for the development of rare-earth-titanium-oxygen cluster scintillators with excellent X-ray scintillation performance and their flexible scintillation films for the further development of high-resolution X-ray imaging technology.

[0006] Since the quality of the scintillator film will seriously affect its X-ray imaging effect, and because the rigid scintillator film can only perform planar imaging on physical objects and is easy to bend and damage, while the flexible scintillator film can perform three-dimensional X-ray imaging on physical objects with irregular shapes and has a wider application range. Therefore, the selection of polymer and the method for realizing large-area film preparation is crucial, and it is equally important to find a solution with good dispersibility for the scintillator. For example, Eu-TiOCs crystals can be evenly dispersed in methanol after slight grinding, which has a great impact on the uniformity of the scintillator ink. Summary of the Invention

[0007] The present invention first proposes using Eu-TiOCs as a scintillator material with excellent X-ray scintillation performance, which has a high light yield and good solution dispersibility, can be uniformly dispersed in methanol solution. Based on this, the present invention provides a scintillator ink based on Eu-TiOCs. By doping rare earth-titanium oxide clusters into a polyvinyl alcohol polymer, a uniform dispersion effect is achieved, and by adjusting the viscosity of the scintillator ink, it is suitable for the scraping function of a microelectronic printer, and thus the ink is coated on a glass substrate to form a scintillator coating. The present invention also pays attention to the post-treatment process of the scintillator coating to facilitate obtaining a film without bubbles, flat and without warping edges. The scintillator film exhibits excellent X-ray imaging effects. The present invention provides a flexible, transparent, large-area, uniform, flat, controllable, and high-resolution scintillator film based on the scintillator ink to meet the needs of high-quality X-ray imaging in many fields.

[0008] The technical solution adopted by the present invention is as follows:

[0009] In the first aspect, the present invention provides a scintillator ink, which is prepared by first completely dispersing Eu-TiOCs crystals in methanol after slight grinding and then mixing and stirring with an aqueous solution of polyvinyl alcohol. The chemical structure of Eu-TiOCs is Eu2Ti4(μ2-O)2(μ3-O)4(phen)2(tbza) 10 ·4CH3CN, named 1,Eu2Ti4-phen-tbza, phen = 1,10-phenanthroline, Htbza = 4-tert-butylbenzoic acid, and the structural formula is C 134 H 146 Eu2N4O 26 Ti4, and in the prepared scintillator ink, the morphology of Eu-TiOCs is a solid spherical shape, with a size between 60 and 100 nm, the concentration of Eu-TiOCs is 10 - 30 mg / mL, the concentration of polyvinyl alcohol is 100 - 130 mg / mL and more preferably 130 mg / mL, and the volume concentration of methanol is 10%.

[0010] Among them, the viscosity of the scintillator ink is adjusted by the addition amount of polyvinyl alcohol. Within the above concentration range, the more the addition amount, the greater the viscosity. If it exceeds the above concentration range, due to the large viscosity, it is difficult to perform magnetic stirring, which will cause uneven dispersion of the scintillator. The scintillator ink of the present invention needs to be prepared strictly in the above-mentioned configuration sequence. If the ground Eu-TiOCs powder particles are directly added to the polyvinyl alcohol aqueous solution, since the polyvinyl alcohol aqueous solution has a large viscosity, it takes at least 4 hours of ultrasonic stirring to disperse it, and small particles will inevitably appear in the ink, and powder particle deposition will occur if the ink stands for a slightly longer time. Therefore, the role of methanol is crucial. Experiments have verified that Eu-TiOCs has good dispersibility in methanol. First, the Eu-TiOCs powder is dispersed in methanol, and then added to the polyvinyl alcohol aqueous solution in the form of a dispersion suspension to avoid direct contact between the powder particles and the polyvinyl alcohol aqueous solution, which is more conducive to the uniform dispersion of the scintillator material in the polymer, and has a direct impact on the uniformity of the subsequent scintillator film and the imaging effect under X-rays.

[0011] Preferably, in the step of fully dispersing the slightly ground Eu-TiOCs crystals in methanol, the way of full dispersion is ultrasonic treatment for at least 10 minutes;

[0012] Preferably, in the step of mixing and stirring with the polyvinyl alcohol aqueous solution, the way of mixing and stirring is magnetic stirring treatment for at least 30 minutes.

[0013] Preferably, the preparation method of the Eu-TiOCs crystals includes the steps of: putting 4-tert-butylbenzoic acid, Eu(Ac)3·6H2O and anhydrous 1,10-phenanthroline into a glass bottle, adding acetonitrile as a reaction solvent, and then adding titanium isopropoxide. After ultrasonic and magnetic stirring, it is placed in an oven at 80°C for 48 hours and then cooled to obtain Eu-TiOCs crystals. Further preferably, the molar mass ratio of the raw material configuration of 4-tert-butylbenzoic acid, Eu(Ac)3·6H2O, and anhydrous 1,10-phenanthroline is 36:5:10, and the molar mass ratio of anhydrous 1,10-phenanthroline to titanium isopropoxide Ti(OiPr)4 is 10:6; further preferably, the specific operation of ultrasonic and magnetic stirring is: after encapsulation, ultrasonic for 30 minutes and magnetic stirring for 1 hour at room temperature, and place in an oven at 80°C for 48 hours; further preferably, the specific operation of the cooling treatment is: programmatic cooling at a rate of -2°C / h for 24 hours and then collect Eu-TiOCs crystals with good crystallinity.

[0014] Second aspect, the present invention provides a scintillator film, which is obtained by coating the above-mentioned scintillator ink on a substrate to form a scintillator coating and then drying it. The thickness range of the scintillator film is 0.08 mm to 0.2 mm; the substrate is selected from a glass substrate or a PET substrate, and the coating method is drop coating, spin coating or microelectronic printing. Drop coating is difficult to achieve large-area film preparation and is slow in operation; spin coating will cause waste of materials; due to the edge effect of the groove in the mold method, the edge part is thicker and the middle part is thinner after film formation, and it is difficult to obtain a large-area uniform film. Therefore, as a preferred embodiment of the present invention, the coating method adopted is preferably scraping with a microelectronic printer. Inject the scintillator ink into the syringe. After installing the syringe and the scraper, set the pressure to 30-50 kPa, the scraping speed to 6-10 mm / s, and the height of the scraper to 29.93-29.98 mm. The pressure is related to the viscosity of the scintillator ink. If the viscosity is large, a relatively higher pressure is required. The scraping speed affects the amount of glue discharged. The height of the scraper, that is, the distance between the scraper and the substrate, can control the thickness of the required scintillator film. The method of scraping with a microelectronic printer is beneficial to quickly coat a uniform scintillator coating, and the viscosity of the scintillator ink used for coating should be relatively large so as to obtain a high-quality scintillator film after rapid drying subsequently.

[0015] The post-treatment process of the scintillator coating will also affect the quality of the film and the imaging effect. In the present invention, the specific steps of the post-treatment process, that is, the drying process, are as follows: Let the scintillator coating stand at room temperature for air drying for 1 day, that is, 24 hours. After being basically dry, place the glass substrate on a heating table at 80°C and heat it for 5-10 minutes to make it further completely dry. Then gently remove the film from the glass substrate with tweezers to obtain a flat, non-warped and large-area flexible transparent film. If the scintillator coating is not placed on the heating table for heating and is only air-dried naturally, it will take at least 2 days, that is, a longer time to dry, and most of the obtained films will be uneven and the edges will be warped; if the scintillator coating is not air-dried naturally and is directly placed on the heating table for heating after coating, the evaporation rate of the solvent will be faster, and a coffee ring phenomenon will occur, making the finally obtained film uneven and seriously affecting its X-ray imaging effect.

[0016] Third aspect, the present invention also provides the application of the above-mentioned scintillator film in X-ray excited luminescence imaging. Specifically, the application method includes: The scintillator film and the substrate material are used as a scintillator screen and applied to an X-ray imaging system. Through the X-ray imaging system, X-ray imaging is performed on an object to obtain an internal structure image of the object. The object includes industrial products or fresh food.

[0017] Further, the above-mentioned scintillator film provided by the present invention is applicable to X-ray excited luminescence imaging of curved surfaces. The specific operation method is as follows: The above-mentioned scintillator film is attached to the lower side of the curved object to be imaged.

[0018] The present invention has the following advantages:

[0019] The present invention first proposes to use Eu-TiOCs as an X-ray scintillator. Eu-TiOCs uses isopropyl titanate as a precursor, and 4-tert-butylbenzoic acid with high coordination ability and a rigid conjugated planar molecule (1,10-phenanthroline) as ligands to construct a rare earth-titanium oxygen cluster compound with a cage structure with the rare earth europium element. Specifically, a rare earth-titanium oxygen cluster compound with the chemical structure C 134 H 146 Eu2N4O 26 Ti4 has good scintillation performance. The specific X-ray radiation luminescence mechanism is described as follows: First, under high-energy radiation, the rare earth-titanium oxygen cluster core Eu2O6Ti4 in the cluster compound absorbs X-rays and deposits energy through Compton scattering and the photoelectric effect. Further, secondary electrons and holes are generated and injected into the triplet energy levels of the organic ligands (4-tert-butylbenzoic acid and 1,10-phenanthroline) through collision ionization, accompanied by the generation and migration of energy. Finally, the ligand sensitizes Eu 3+ , exciting the luminescence center Eu 3+ to produce characteristic luminescence. The introduction of the second ligand 1,10-phenanthroline not only helps to effectively capture high-energy electrons, but also further satisfies the coordination number of Eu 3+ , reducing non-radiative transitions. At the same time, the triplet energy level of 1,10-phenanthroline 21189cm -1 is between the 24630cm of 4-tert-butylbenzoic acid -1 and the 3+ ion 5 D0 energy level 17200cm -1 of Eu 3+ ion 5 between, so it can play a bridging role and improve the energy transfer efficiency from the ligand to the D0 energy level of the Eu 3+ ion 5 . In addition to the above effective antenna sensitization, the rigid cage structure of the Eu-TiOCs core provides the smallest thermal vibration. In addition, the presence of hydrophobic groups around the cluster core effectively inhibits the coordination of water molecules, thereby reducing fluorescence quenching caused by O-H stretching vibration. As a result, the XEL performance of Eu-TiOCs is synergistically enhanced.

[0020] Beneficial effects:

[0021] 1. The scintillator ink formulation of the present invention is simple and feasible. Since Eu-TiOCs has good dispersibility in methanol, Eu-TiOCs is first dispersed in methanol, and then the dispersion is added to an aqueous solution of polyvinyl alcohol and stirred to mix evenly. This avoids the direct contact of Eu-TiOCs particles with the aqueous solution of polyvinyl alcohol, helps to uniformly dope the scintillator material into the polymer in a short time, and is not prone to sedimentation after standing, providing a scintillator ink formulation with uniform dispersion and no particle feeling.

[0022] 2. The scintillator ink provided by the present invention can be used to prepare a scintillator thin film by the scraping function of a microelectronic printer, which can meet the requirements of a large-area, controllable thickness, uniform, flexible and transparent thin film. The post-treatment process of natural air drying first and then heating for further drying of the scintillator coating is beneficial to obtaining a flat thin film without warping. The high-quality thin film obtained can reach a resolution of about 13 lp / mm under X-ray excitation, which is higher than the spatial resolution requirements of the existing commercial scintillator screens. And due to the fact that the small-sized scintillators provided by the present invention can be uniformly dispersed in the polymer matrix, the flexibility of the prepared scintillator thin film enables it to achieve the effect of curved surface imaging. Brief Description of the Drawings

[0023] Figure 1 It is a TEM electron microscope analysis diagram of Eu-TiOCs cluster dispersed into a methanol solution;

[0024] Figure 2 It is the radiation emission spectrum of Eu-TiOCs cluster;

[0025] Figure 3 It is the PXRD powder X-ray diffraction characteristic peak pattern of the Eu-TiOCs cluster prepared in Example 1;

[0026] Figure 4a It is a schematic diagram of the flexibility of the scintillator thin film prepared in Example 2;

[0027] Figure 4b It is a schematic diagram of the transparency of the scintillator thin film prepared in Example 2;

[0028] Figure 5 It is an X-ray excitation diagram of the Eu-TiOCs scintillator thin film prepared in Example 2 covering an on-line pair card;

[0029] Figure 6 It is a chip and crab imaging picture of the scintillator thin film prepared in Example 2;

[0030] Figure 7a It is a schematic diagram of the transparency of the scintillator thin film prepared in Example 3;

[0031] Figure 7bThe imaging picture of the scintillator thin film wire pair card prepared in Example 3;

[0032] Figure 8a The wire pair card of the scintillator thin film prepared in Example 4;

[0033] Figure 8b The photo after X-ray imaging of the chip and the scintillator thin film prepared in Example 4;

[0034] Figure 9a The flexibility of the scintillator thin film prepared in Example 5;

[0035] Figure 9b The schematic diagram of the transparency of the scintillator thin film prepared in Example 5;

[0036] Figure 10a The wire pair card of the scintillator thin film prepared in Example 5;

[0037] Figure 10b The photo after X-ray imaging of the chip and the scintillator thin film prepared in Example 5;

[0038] Figure 11 The MTF curve of the scintillator thin film prepared in Example 5 measured by the hypotenuse method, and the inset in the upper right corner is the hypotenuse picture of the thin film;

[0039] Figure 12a The X-ray imaging effect when the scintillator thin film prepared in Example 5 is placed flat under the flexible cable;

[0040] Figure 12b The X-ray imaging effect when the scintillator thin film prepared in Example 5 is attached under the flexible cable. Detailed implementation manners

[0041] The technical solutions of the present invention will be further described below in conjunction with the accompanying drawings. All examples give detailed operation steps, but the protection scope of the present invention is not limited to the following examples.

[0042] All raw material reagents are directly purchased commercial reagents without further purification.

[0043] Europium(III) acetate hexahydrate: Shanghai Aladdin Biochemical Technology Co., Ltd.

[0044] 4-tert-Butylbenzoic acid: Shanghai Aladdin Biochemical Technology Co., Ltd.

[0045] 1,10-Phenanthroline (anhydrous): Shanghai Aladdin Biochemical Technology Co., Ltd.

[0046] Isopropyl titanate: Shanghai Macklin Biochemical Co., Ltd.

[0047] Acetonitrile: Sinopharm Chemical Reagent Co., Ltd.

[0048] Methanol: Sinopharm Chemical Reagent Co., Ltd.

[0049] Polyvinyl alcohol type 1799: Shanghai Macklin Biochemical Co., Ltd.

[0050] Equipment model and manufacturer:

[0051] X-ray tube system: Mini-X2, Amptek. Mini-X2 as the X-ray tube system includes an X-ray tube, a power supply, control electronics, and USB communication with a computer. Amptek is the company name.

[0052] Microelectronic printer: Powerway Technology PrtronicScientific3 microelectronic printer.

[0053] The following X-ray resolution and imaging tests were carried out using the above X-ray tube system. Specifically, by placing a spatial resolution standard test line pair card above the scintillator film and vertically aligning the X-ray tube with the film to excite luminescence, the spatial resolution of the scintillator film was obtained. The spatial resolution is also an important parameter for evaluating the imaging ability of the scintillator. The larger the spatial resolution, the higher the imaging ability of the scintillator and the clearer the image obtained. In addition, by attaching the flexible scintillator film under the flexible flat cable and using the same imaging operation as that of the above digital chip and crab, curved surface imaging can be performed.

[0054] Example 1

[0055] Preparation of Eu-TiOCs clusters: Add 0.36 mmol of 4-tert-butylbenzoic acid, 0.05 mmol of Eu(Ac)3·6H2O, 0.1 mmol of anhydrous 1,10-phenanthroline to a 4 mL vial, add 3 mL of acetonitrile, and then slowly dropwise add 0.06 mmol of titanium isopropoxide Ti(OiPr)4. After encapsulation, ultrasonicate for 30 min at room temperature, stir magnetically for 1 hour, place in an 80 °C oven and react for 48 h, then cool down programmatically for 24 h (2 °C / h). After 24 h, well-crystallized crystals were collected.

[0056] Disperse the Eu-TiOCs clusters into a methanol solution and ultrasonicate for 15 min. After the ultrasonication, carefully take out the copper grid with forceps with the film side facing up, drop an appropriate amount of the sample on the copper grid, let it stand and volatilize, and then perform TEM electron microscopy scanning analysis, as Figure 1As shown, the particles are solid spheres with a nanosize between 60 and 100 nm. Compared with the previously reported scintillators, their size is smaller and the light scattering is small. First, Eu-TiOCs was dispersed in methanol for TEM scanning electron microscopy analysis. It can be seen that its size is between 60 and 100 nm, indicating that the particle size of Eu-TiOCs dispersed in methanol is small. Secondly, according to the previously reported literature, the smaller the particle size of the scintillator, the smaller the scattering when converting X-rays into visible light, thereby improving the spatial resolution. From Figure 1 It can be seen that the Eu-TiOCs cluster material obtained has good dispersibility and uniform size distribution, and can also meet the requirements of biomedical imaging agents. Such as Figure 2 Shown is the radioluminescence spectrum of Eu-TiOCs clusters under X-rays. Under X-ray excitation, characteristic emission peaks of europium ions can be emitted, with strong sharp peaks at 590 nm, 614 nm, 622 nm, 652 nm, and 700 nm respectively. Such as Figure 3 Figure 6 is the PXRD powder X-ray diffraction characteristic peak pattern of the Eu-TiOCs clusters prepared in Example 1. The main peaks of the PXRD powder diffraction characteristics of the obtained Eu-TiOCs clusters all correspond to the simulation results of single crystal data, indicating that the phase purity of the synthesized Eu-TiOCs cluster single crystal is relatively high.

[0057] Example 2

[0058] Preparation of scintillator ink: Add 1300 mg of polyvinyl alcohol to 10 mL of deionized water, heat and stir in a sand bath for 5 h to completely dissolve it. The temperature of the sand bath is 90 °C. Let it stand for 10 h to eliminate bubbles. After slightly grinding 100 mg of Eu-TiOCs crystals, add 1 mL of methanol and ultrasonicate for 10 min to fully disperse it. Then add the dispersed suspension to the above polyvinyl alcohol aqueous solution and stir magnetically for 30 min to mix evenly to obtain the scintillator ink.

[0059] Preparation of scintillator film through the doctor blade function of a microelectronic printer: Inject the scintillator ink into a syringe. After installing the syringe and the doctor blade, set the doctor blade pressure to 30 kPa, the doctor blade speed to 6 mm / s, the doctor blade height to 29.95 mm, and the doctor blade area to 24 cm 2 , After doctor blading, let the scintillator coating air dry at room temperature for 1 d. After it is basically dry, place it on a heating table at 80 °C and heat for 5 - 10 min to obtain a flat scintillator film with a film thickness of 0.1 mm. Such as Figure 4a Shown is the flexibility schematic diagram of the scintillator film prepared in Example 2. Such as Figure 4b Shown is the transparency schematic diagram of the scintillator film prepared in Example 2.

[0060] X-ray resolution and imaging test: Spatial resolution is also an important parameter for evaluating the imaging ability of the scintillator. The larger the spatial resolution, the higher the imaging ability of the scintillator, and the clearer the image obtained. We placed the spatial resolution standard test line pair card above the scintillator film, and vertically aligned the X-ray tube to excite the film to emit light. Among them, the emission current of the X-ray source is 50 μA, the voltage is 70 kV, and the distance from the X-ray tube to the film is 2 - 3 cm. Finally, we obtained an imaging picture as shown in Figure 5 The resolution of which is 8 lp / mm. To further verify the X-ray imaging ability of Eu-TiOCs in actual scenarios, a digital chip and a pin crab were respectively selected as industrial and biological specimens as imaging objects, and the imaging effect was photographed with a camera, as shown in Figure 6 shown.

[0061] Example 3

[0062] Preparation of scintillator ink: The same ink preparation process as in Example 2 was adopted.

[0063] Preparation of scintillator film by the scraping function of a microelectronic printer: The same film preparation process as in Example 2 was adopted, except that the pressure was changed to 50 kPa, the scraping speed was changed to 10 mm / s, and the height of the scraper was changed to 29.98 mm.

[0064] X-ray resolution and imaging test: The same resolution and imaging operation process as in Example 2 were adopted. As shown in Figure 7a is a schematic diagram of the transparency effect of the scintillator film prepared in Example 3, and Figure 7b is an imaging picture of the scintillator film prepared in Example 3 on the line pair card. It can be seen that its resolution is 9 lp / mm.

[0065] Example 4

[0066] Preparation of scintillator ink: 1300 mg of polyvinyl alcohol was added to 10 mL of deionized water, heated and stirred in a sand bath for 5 h to completely dissolve it. The temperature of the sand bath was 90 °C. After standing for 10 h to eliminate bubbles, 300 mg of Eu-TiOCs crystals were gently ground and then added to 1 mL of methanol, and ultrasonicated for 10 min to fully disperse it. Then the dispersed suspension was added to the above polyvinyl alcohol aqueous solution, and magnetically stirred for 30 min to mix evenly to obtain the scintillator ink.

[0067] Preparation of scintillator film by the scraping function of a microelectronic printer: The same film preparation process as in Example 2 was adopted, except that the height of the scraper was changed to 29.93 mm.

[0068] X-ray resolution and imaging test: The same resolution and imaging operation process as in Example 2 were adopted. As shown in Figure 8a is the line pair card of the scintillator film prepared in Example 4, as shown inFigure 8b The imaging picture of the scintillator film prepared in Example 4 for chip X-ray is shown. It can be seen that its resolution is 9 lp / mm.

[0069] Example 5

[0070] Preparation of scintillator ink: Add 1300 mg of polyvinyl alcohol to 10 mL of deionized water, heat and stir in a sand bath for 5 h until completely dissolved. The temperature of the sand bath is 90 °C. Let it stand for 10 h to remove bubbles. After slightly grinding 200 mg of Eu-TiOCs crystals, add them to 1 mL of methanol and ultrasonicate for 10 min to disperse them fully. Then add the dispersed suspension to the above polyvinyl alcohol aqueous solution and stir magnetically for 30 min to mix evenly to obtain the scintillator ink.

[0071] Preparation of scintillator film by the doctor blade function of a microelectronic printer: Use the same film preparation process as in Example 2, except that the height of the doctor blade is changed to 29.94 mm. As Figure 9a The flexibility of the scintillator film prepared in Example 5, as Figure 9b The transparency schematic diagram of the scintillator film prepared in Example 5.

[0072] X-ray resolution and imaging test: Use the same resolution and imaging operation process as in Example 2. As Figure 10a The line pair card of the scintillator film prepared in Example 5, Figure 10b The X-ray imaging picture of the scintillator film prepared in Example 5 for the chip is shown. It can be seen that its resolution is 13 lp / mm. To further accurately determine the resolution value, perform MTF calculation on the obtained Figure 10b to obtain the calculation result as shown in Figure 11 to obtain a high spatial resolution of 12.3 lp / mm -1 where the modulation transfer function (MTF) = 0.2, which matches the result obtained from the standard resolution test line pair card of about 13 lp / mm -1 and is higher than the spatial resolution requirement of the currently used commercial scintillator screen.

[0073] Example 6

[0074] Operation of curved surface imaging: Place the scintillator film prepared in Example 2 flat under the flexible circuit and perform X-ray imaging (planar imaging) using the same imaging operation process as in Example 2. As Figure 12a The imaging picture when the scintillator film is placed flat under the flexible circuit; at the same time, attach the scintillator film to the bottom of the flexible circuit and perform the same imaging operation (curved surface imaging), as Figure 12bIt is an imaging picture when the scintillator film is attached under the flexible circuit board. It can be seen that the edge part of the planar imaging pattern is relatively blurred, while the edge part of the curved surface imaging pattern is clearer. This further provides an idea for the flexible scintillator film to perform clear X-ray imaging on curved surface objects.

Claims

1. A scintillator ink, characterized in that, The scintillator ink is prepared by first completely dispersing Eu-TiOCs crystals after slight grinding in methanol and then mixing and stirring with an aqueous solution of polyvinyl alcohol. The chemical structure of Eu-TiOCs is Eu2Ti4 (μ2 -O)2 (μ3 -O)4(phen)2(tbza) 10 ·4CH3CN. In the prepared scintillator ink, the morphology of Eu-TiOCs is solid spherical, with a size between 60 and 100 nm, the concentration of Eu-TiOCs is 10 to 30 mg / mL, the concentration of polyvinyl alcohol is 100 to 130 mg / mL, and the volume concentration of methanol is 10%.

2. A scintillator ink as claimed in claim 1, wherein, In the step of mixing and stirring with the aqueous solution of polyvinyl alcohol, the mixing and stirring method is magnetic stirring treatment for at least 30 min.

3. A scintillator ink as claimed in claim 1, characterized in that, The preparation method of the Eu-TiOCs crystal includes the steps of: placing 4-tert-butylbenzoic acid, Eu(Ac)3·6H2O and anhydrous 1,10-phenanthroline in a glass bottle, adding acetonitrile as a reaction solvent, and then adding isopropyl titanate. After ultrasonic and magnetic stirring, it is placed in an oven at 80 °C for reaction for 48 h, and then cooled to obtain Eu-TiOCs crystal.

4. A scintillator ink as claimed in claim 3, wherein The molar mass ratio of the raw material configurations of the 4-tert-butylbenzoic acid, Eu(Ac)3·6H2O, and anhydrous 1,10-phenanthroline is 36:5:10, and the molar mass ratio of the anhydrous 1,10-phenanthroline to the isopropyl titanate Ti(OiPr)4 is 10:

6.

5. A scintillator ink as claimed in claim 3, characterized in that, The specific operation of the ultrasonic and magnetic stirring is: after encapsulation, ultrasonic for 30 min and magnetic stir for 1 hour at room temperature, and then place it in an oven at 80 °C for reaction for 48 h.

6. A scintillator ink according to claim 3, characterized in that The specific operation of the cooling treatment is: programmatic cooling at a rate of -2 °C / h for 24 h, and then collect Eu-TiOCs crystals with good crystallinity.

7. A scintillator thin film, characterized in that, The scintillator film is obtained by coating the scintillator ink described in any one of claims 1 to 6 on a substrate to form a scintillator coating and then drying it. The thickness range of the scintillator film is 0.08 mm to 0.2 mm; The substrate is selected from a glass substrate or a PET substrate; The coating method is drop coating, spin coating or microelectronic printing; the drying treatment step includes: allowing the scintillator coating to stand and air dry at room temperature for 24 hours. After drying, place the glass substrate on a heating table at 80 °C and heat for 5-10 min to prepare the scintillator film.

8. A scintillator thin film according to claim 7, wherein The coating method is microelectronic printing and is the doctor blade coating method of microelectronic printing. The specific operation is: inject the scintillator ink into a syringe. After installing the syringe and the doctor blade, set the pressure to 30-50 kPa, the doctor blade speed to 6-10 mm / s, and the doctor blade height to 29.93-29.98 mm.

9. Application of the scintillator film according to claim 7 in X-ray excited luminescence imaging. The scintillator film and the substrate material are used as a scintillator screen, and X-ray imaging of an object is performed through an X-ray imaging system to obtain an internal structure image of the object.

10. The application according to claim 9, characterized in that, The scintillator film is used for X-ray excited luminescence imaging of a curved object. The specific operation method is: attach the above scintillator film below the curved object to be imaged.

Images