Reflection type ultrafast scintillation vacuum ultraviolet light imaging detection system and method thereof

Abstract

The invention relates to the field of electronic detectors, and discloses a reflective ultrafast scintillation vacuum ultraviolet light imaging detection system and a method thereof.The reflective ultrafast scintillation vacuum ultraviolet light imaging detection system comprises a light path system, a detection and recording component and a structure supporting component, and the light path system is in reflective light path configuration and comprises a primary mirror, a secondary mirror, a correction lens, an integrated filter and a vacuum ultraviolet scintillator; and the vacuum ultraviolet scintillator is made of a PEA2PbBr4 crystal or a BA2PbBr4 crystal. According to the invention, by constructing reflective optical path configuration, the capability of the device in vacuum ultraviolet (VUV) scintillation imaging is successfully shown. The invention not only provides a new solution for reducing the influence of the self-absorption effect in the perovskite scintillator, but also establishes a bridge between the perovskite scintillator and the perovskite scintillator actually applied to ultrafast VUV detection, and opens up a new way for the application of the perovskite material in the field of VUV imaging.

Description

Technical Field

[0001] The present invention relates to the field of electronic detectors, and in particular to a reflective ultrafast scintillation vacuum ultraviolet light imaging detection system and a method thereof. Background Art

[0002] Vacuum ultraviolet (VUV) light detection technology, with a wavelength range of 10 to 200 nm, plays a crucial role in space science and radiation monitoring, providing indispensable support for space exploration missions, space physics research, and applications of synchrotron radiation sources and free-electron lasers. By accurately capturing VUV radiation emitted by various astronomical objects, this technology provides invaluable data for cutting-edge scientific research, such as space weather forecasting and exploration of the origin and evolution of the universe. With the growing demand for VUV light detection, research on photodetectors based on wide-bandgap semiconductor materials such as diamond, aluminum nitride (AlN), and gallium oxide (Ga2O3) has become increasingly critical. To accurately capture the motion details of targets in VUV radiation environments, ideal detectors should possess a fast response time in the picosecond range. However, these high-performance detectors face numerous challenges in practical application, including high manufacturing costs, complex integration processes, and difficulty achieving the desired fast response time. Therefore, developing a VUV light detection method that combines simple synthesis with fast response characteristics has become a major technical challenge that needs to be addressed.

[0003] As an alternative research path, researchers are actively exploring the application potential of high-performance scintillating materials, which can effectively convert vacuum ultraviolet (VUV) light into visible light and accurately capture VUV light imaging information while achieving rapid scintillation. Specifically, organic scintillators have been successfully used in the detection of VUV light imaging information. Han et al. developed a real-time monitoring system for VUV radiation based on sodium salicylate and compared the photon intensity in different wavelength ranges using various filters. However, it is worth noting that the hygroscopicity and aging of sodium salicylate scintillators may have an adverse effect on their long-term working performance, which is mainly attributed to the system's susceptibility to environmental pollutants (such as vacuum pump oil), ultraviolet radiation, and water vapor. Therefore, although organic scintillators have shown good performance in certain specific application scenarios, they may not be the best choice in terms of long-term stability. Summary of the Invention

[0004] To address the shortcomings of the existing technology, the present invention provides a reflective ultrafast scintillation vacuum ultraviolet light imaging detection system and method. The imaging detection system of the present invention has a response time approximately 2.6 times faster than that of traditional transmission systems, providing a new technical path for ultrafast detection in the vacuum ultraviolet (VUV) band.

[0005] To achieve the above object, the present invention is implemented through the following technical solutions:

[0006] In a first aspect of the present invention, a reflective ultrafast scintillation vacuum ultraviolet imaging detection system is provided, comprising an optical path system, a detection and recording component, and a structural support component. The optical path system is a reflective optical path configuration, and a secondary mirror, a primary mirror, an integrated filter, and a vacuum ultraviolet scintillator are sequentially arranged in front and behind the optical path system; wherein,

[0007] The optical path system is further provided with a correction lens, the diameter of the correction lens is larger than the diameter of the secondary mirror, and the correction lens is sleeve-connected to the secondary mirror or located at the front end of the optical path system;

[0008] The structure of the primary mirror is a concave lens, and the structure of the secondary mirror is a convex lens;

[0009] The material of the vacuum ultraviolet scintillator is PEA2PbBr4 crystal or BA2PbBr4 crystal.

[0010] Furthermore, a hollow sleeve is inserted into the middle of the primary mirror, and the integrated filter is installed at the rear end of the hollow sleeve.

[0011] Furthermore, the integrated filter is composed of an outer protective layer, a metal reflective layer, a multilayer interference film, an absorption layer and a VUV transmission substrate.

[0012] Furthermore, the outer protective layer material of the integrated filter is ultra-thin Si3N4; the material of the metal reflective layer is aluminum film; the multilayer interference film is Si / Mo alternating layers; the absorption layer material is carbon film; and the VUV transmission substrate is a LiF window.

[0013] Furthermore, the thickness of the ultra-thin Si3N4 is less than 10nm; the thickness of the aluminum film is 40-60nm; the total thickness of the Si / Mo alternating layer is 400-600nm; the thickness of the carbon film is 15-25nm; and the thickness of the LiF window is 1-2mm.

[0014] Furthermore, the detection and recording component is a charge coupled device, and the structural support component is a lens barrel.

[0015] Furthermore, the preparation method of the vacuum ultraviolet scintillator material PEA2PbBr4 or BA2PbBr4 crystal comprises the following steps:

[0016] Step S1, dissolving phenylethylamine hydrobromide or butylammonium bromide: lead bromide in a stoichiometric ratio of 2:1 in N,N-dimethylformamide solvent, stirring, heating, and then filtering to obtain a polycrystalline material and a transparent saturated precursor solution 1;

[0017] Step S2, dissolving the polycrystalline material in N,N-dimethylformamide to obtain a new saturated precursor solution 2, and evaporating and crystallizing the precursor solution 1 at room temperature to obtain transparent PEA2PbBr4 or BA2PbBr4 seed crystals;

[0018] Step S3: adding seed crystals to the precursor solution 2 and slowly evaporating and further growing to obtain PEA2PbBr4 or BA2PbBr4 crystals.

[0019] Furthermore, in step S1 of the method for preparing PEA2PbBr4 or BA2PbBr4 crystals, after stirring and heating at a temperature of 50 to 80°C for 20 to 30 hours, the polycrystalline material and the transparent saturated precursor solution 1 are obtained by filtration.

[0020] Furthermore, in step S3 of the method for preparing PEA2PbBr4 or BA2PbBr4 crystals, slow evaporation is performed at a temperature of 20 to 40°C for 60 to 84 hours to further grow PEA2PbBr4 or BA2PbBr4 crystals.

[0021] The second aspect of the present invention provides a detection method for the above-mentioned reflective ultrafast scintillation vacuum ultraviolet imaging detection system, in which the light is processed by the reflective optical path configuration of the optical path system, including the following steps: after the light is corrected by the correction lens, it is reflected by the concave lens of the primary mirror, and then the optical path is adjusted by the converging effect of the convex lens of the secondary mirror, and then the vacuum ultraviolet light with a wavelength range of 10 to 200 nm is filtered by the integrated filter, and the vacuum ultraviolet light that has been filtered is finally clearly imaged on the vacuum ultraviolet scintillator; the optical signal processed by the optical path system is converted into an electrical signal by the detection and recording component and stored and transmitted.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. By optimizing the optical path system, the present invention enables the imaging detection system to effectively avoid self-absorption and utilize surface excitons to achieve efficient light utilization and rapid scintillation. Through the coordinated operation of various components, the imaging system of the present invention can achieve high-quality imaging of specific targets and within specific spectral ranges, with potential applications in astronomical observation, spectral analysis, and other fields.

[0024] 2. The PEA2PbBr4 crystal or BA2PbBr4 crystal prepared by the present invention exhibits extremely high transparency and can clearly transmit the text underneath, which provides a solid foundation for its application in the field of imaging applications.

[0025] 3. The PEA2PbBr4 crystal of the present invention has a fast decay time, can provide higher time resolution, and can be used to accurately capture and analyze transient events; in addition, the PEA2PbBr4 crystal of the present invention performs well in terms of luminous efficiency, providing strong support for its application in high-performance detection systems.

[0026] 4. By constructing a reflective optical imaging system for VUV light, this invention can quickly and clearly capture imaging details, thereby achieving clear imaging, with performance far exceeding that of traditional scintillators. Therefore, it fully demonstrates its huge potential in the field of scintillation imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the structure and optical path of the reflective ultrafast scintillation vacuum ultraviolet imaging detection system of Example 1 of the present invention.

[0028] Figure 2 a is an optical photograph of the PEA2PbBr4 crystal of Example 2 of the present invention under white light; Figure 2 b and Figure 2 c are the SEM images of the (001) top view and (010) cross section of the PEA2PbBr4 single crystal of Test Example 1; Figure 2 d is the powder XRD pattern of PEA2PbBr4 single crystal and theoretical calculation.

[0029] Figure 3 This is an optical photograph of the BA2PbBr4 crystal of Example 2 of the present invention under white light.

[0030] Figure 4 This is a summary diagram and schematic diagram of the decay time of PEA2PbBr4 crystal under different excitation sources in Test Example 2 of the present invention.

[0031] Figure 5 a is a graph showing the absorption coefficient and penetration depth of the PEA2PbBr4 single crystal obtained in Example 2 of the present invention; Figure 5 b is a schematic diagram of the penetration depth of vacuum ultraviolet light, ultraviolet light and X-ray in PEA2PbBr4 single crystal.

[0032] Figure 6 This is the UV-visible transmission spectrum of the PEA2PbBr4 single crystal of Test Example 3 of the present invention.

[0033] Figure 7 a and Figure 7 b are the photoluminescence spectra of the PEA2PbBr4 crystal of Test Example 3 of the present invention measured in reflection and transmission modes under 193nm excitation.

[0034] Figure 8The time-resolved fluorescence spectrum of PEA2PbBr4 of Test Example 3 of the present invention with emission peaks at 409nm and 435nm under 213nm excitation is shown.

[0035] Figure 9 a is a histogram of the decay time of the PEA2PbBr4 crystal of Test Example 4 of the present invention and common scintillators; Figure 9 b is a three-dimensional comparison diagram of PLQY, decay time, and emission peak of the PEA2PbBr4 crystal of test example 4 of the present invention and common commercial scintillators sodium salicylate and YAG:Ce.

[0036] Figure 10 a is a temperature-dependent TRPL-Mapping diagram of Test Example 5 of the present invention at 409 nm; Figure 10 b is the decay time variation of the 409 nm emission peak with temperature; Figure 10 c is an imaging photograph of the reflective ultrafast scintillation vacuum ultraviolet imaging detection system based on Example 1 in Test Example 5 of the present invention.

[0037] In the picture:

[0038] 1- Primary mirror (concave lens); 2- Secondary mirror (convex lens); 3- Correction lens; 4- Integrated filter; 5- Vacuum ultraviolet scintillator; 6- Detection and recording components (charge-coupled device); 7- Structural support components (lens barrel). DETAILED DESCRIPTION

[0039] Below in conjunction with the accompanying drawings in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is clearly and completely described, it is obvious that described embodiment is only a part of embodiment of the present invention, rather than whole embodiments. Based on the embodiment in the present invention, those of ordinary skill in the art, without making the every other embodiment obtained under the creative work premise, all fall within the scope of protection of the present invention. Unless otherwise stated, the reagent, method and equipment adopted in the present invention are conventional reagents, methods and equipment in the art.

[0040] Example 1: Reflective Ultrafast Scintillation Vacuum Ultraviolet Light Imaging Detection System and Method

[0041] This embodiment is used to provide the reflective ultrafast scintillation vacuum ultraviolet imaging detection system and method of the present invention. Figure 1 The structure and optical path diagram of the reflective ultrafast scintillation vacuum ultraviolet imaging detection system of the present invention is shown in FIG. Figure 1As shown in the structural schematic diagram, a reflective ultrafast scintillation vacuum ultraviolet imaging detection system is composed of three parts: an optical path system, a detection and recording component, and a structural support component. The optical path system of the imaging detection system is sequentially provided with a secondary mirror 2, a primary mirror 1, an integrated filter 4, and a vacuum ultraviolet scintillator 5 in front and back; the optical path system is also provided with a correction lens 3, the diameter of the correction lens 3 is larger than the diameter of the secondary mirror 2, and the correction lens 3 is connected to the secondary mirror 2 or is located at the front end of the optical path system; as a specific embodiment, a hollow sleeve is inserted in the middle of the primary mirror 1, and the integrated filter 4 is installed at the rear end of the hollow sleeve.

[0042] In the present invention, the structural support component may be a lens barrel 7, and the detection and recording component may be a charge coupled device 6.

[0043] The primary mirror 1 is a concave lens, which is used as a core component to collect and initially converge light from the target. It uses the reflection characteristics of the concave mirror to propagate the light in a specific direction.

[0044] Secondary mirror 2 is a convex lens that further processes the light reflected from the primary mirror. The converging effect of the convex lens can adjust the light path, allowing the light to focus more accurately and improve the accuracy of imaging;

[0045] Correction lens 3 is used to correct aberrations, chromatic aberrations, and other problems generated during light propagation, making imaging clearer and more accurate, and reducing image distortion caused by the characteristics of the optical element itself; specifically, correction lens 3 can be a Schmidt correction lens;

[0046] The integrated filter 4 is specifically composed of an outer protective layer (ultra-thin silicon nitride, Si3N4, thickness <10nm, used to prevent oxidation and mechanical damage), a metal reflective layer (aluminum film, thickness approximately 50nm, used to reflect visible light / infrared), a multilayer interference film (Si / Mo alternating layers, total thickness approximately 500nm, used to enhance VUV transmission and secondary reflect stray light), an absorption layer (carbon film, thickness approximately 20nm, used to absorb the long-wave residual transmitted), and a VUV-transmitting substrate (LiF window, thickness 1-2mm, used to provide mechanical support and final VUV transmission). In the present invention, the integrated filter 4 is used to filter the passage of ultraviolet light in a specific wavelength range (wavelength 10-200nm) and block other interfering wavelengths.

[0047] The vacuum ultraviolet scintillator 5 can be made of a VUV scintillator, such as a PEA2PbBr4 crystal or a BA2PbBr4 crystal. When vacuum ultraviolet light is incident, the scintillator 5 can convert vacuum ultraviolet photons into visible light photons, thereby converting invisible vacuum ultraviolet light into visible light for subsequent detection.

[0048] The detection and recording component (charge-coupled device 6) is used to convert the optical signal processed by the optical path system into an electrical signal, and store and transmit it. It is a key component for converting optical images into electronic data for subsequent processing and display.

[0049] Structural support component (lens barrel 7): plays the role of supporting and protecting the internal optical components, ensuring the relative position of each component is accurate and maintaining the stability of the optical path.

[0050] In the present invention, a reflective ultrafast scintillation vacuum ultraviolet imaging detection method is provided, such as Figure 1 As shown in the optical path diagram of FIG, light passes through the reflective optical path configuration of the optical path system to process the optical signal, including the following steps:

[0051] After the light passes through the correction lens 3 to adjust the light path by correcting the light propagation, it is reflected by the concave lens of the primary mirror 1, and then adjusted by the converging effect of the convex lens of the secondary mirror 2. It then passes through the integrated filter 4, which can filter the vacuum ultraviolet light in a specific wavelength range (10 to 200 nm). The vacuum ultraviolet light filtered by the filter 4 is clearly imaged on the vacuum ultraviolet scintillator 5.

[0052] The optical signal processed by the optical system is converted into an electrical signal for storage and transmission by a detection and recording component, which is configured as a charge-coupled device 6. By optimizing the design of the optical system, the imaging detection system of the present invention effectively avoids self-absorption, thereby achieving efficient light utilization and rapid scintillation. Through the coordinated operation of various components, the imaging system of the present invention can achieve high-quality imaging of specific targets and within specific spectral ranges, and has potential applications in astronomical observation, spectral analysis, and other fields.

[0053] Example 2: Growth Method of Vacuum Ultraviolet Scintillator PEA2PbBr4 and BA2PbBr4 Single Crystals

[0054] This embodiment provides a method for growing PEA2PbBr4 crystals of the vacuum ultraviolet scintillator 5 in the imaging detection system of the present invention. In this embodiment, all experimental reagents and solvents were purchased commercially without further purification.

[0055] Traditional anti-solvent diffusion crystallization methods usually produce crystal particles with small size (mostly a few millimeters), uneven surface and low transparency. These characteristics limit its potential in practical applications such as imaging. Based on this, the present invention adopts a strategy of combining solvent evaporation with seed crystal induced growth to promote further crystal growth. The seed crystals are placed in a saturated N,N-dimethylformamide (DMF) solution and evaporated at room temperature to synthesize PEA2PbBr4 or BA2PbBr4 crystals. The synthetic growth method of PEA2PbBr4 or BA2PbBr4 crystals specifically includes the following steps:

[0056] Step S1, dissolving phenylethylamine hydrobromide (PEABr) or butylammonium bromide (BABr) and lead bromide (PbBr2) in a stoichiometric ratio of 2:1 in N,N-dimethylformamide (DMF) solvent, stirring and heating at 65°C for 24 hours, and filtering to obtain a PEA2PbBr4 or BA2PbBr4 polycrystalline material and a transparent saturated precursor solution 1;

[0057] Step S2, dissolving the polycrystalline material in DMF to obtain a new saturated precursor solution 2; evaporating and crystallizing the precursor solution 1 at room temperature to obtain transparent PEA2PbBr4 or BA2PbBr4 seed crystals;

[0058] Step S3: Finally, the seed crystal is added to the precursor solution 2 and slowly evaporated at 30°C for 72 hours to further grow to obtain PEA2PbBr4 crystals (20mm×12mm×2mm) or BA2PbBr4 crystals (30mm×7mm×1mm) with high transparency and larger size.

[0059] Using the above preparation method, this example successfully synthesized transparent and flat PEA2PbBr4 crystals and BA2PbBr4 crystals with sizes of 11mm×8mm and 30mm×7mm respectively. The optical photographs of PEA2PbBr4 crystals and BA2PbBr4 crystals under white light are shown as follows: Figure 2 a and Figure 3 As shown. Figure 2 a and Figure 3 It can be seen that the PEA2PbBr4 crystals and BA2PbBr4 crystals prepared in this embodiment exhibit extremely high transparency and can clearly transmit the text or pattern underneath, which provides a solid foundation for their application in the field of imaging applications.

[0060] Example 3. Test characterization methods and instruments

[0061] This embodiment is used to provide the test characterization methods and instrumentation used in the following test examples. In the following test examples, X-ray diffraction (XRD) was performed on a Panalytical X'Pert Pro X-ray diffractometer with a copper X-ray tube voltage of 45 kV and a current of 40 mA. The calculated XRD results were obtained based on Crystal Maker and Crystal Diffract software. Scanning electron microscope (SEM) images were obtained on a Hitachi SU5000 instrument at an accelerating voltage of 10 kV, with the top view and cross-section magnifications of 120 and 2500, respectively.

[0062] UV-visible spectra were measured using a Shimadzu UV-3600-Plus spectrophotometer. PL spectroscopy was performed using an EX5 / 250-478 excimer 193 nm (ArF) laser, a DPS-213-Pico diode-pumped all-solid-state 213 nm picosecond laser (pulse width: 44.37 ps), and a 365 nm LED. The optical signal was collected using an Ocean Optical QE65 Pro spectrometer. Transient photoluminescence (TRPL) spectroscopy was performed using a specially designed VUV Edikurgh FLS1000 transient photoluminescence spectrometer equipped with a 213 nm picosecond laser. The sample was kept in a cryostat maintained at low temperature with liquid nitrogen. The temperature was adjusted from 77 K to 300 K by an automatic thermostat, with recordings taken at every 10 K increment. Time-resolved radiation decay times were measured using time-correlated single photon counting (TSPC) using an Ammonium γ-ray source as the excitation source. The measurements were performed using a Hamamatsu R2083 PMT and a Lecroy oscilloscope with a 1 GHz bandwidth and a 10 GS / s sampling rate. All optical images were captured using a Nikon D850 optical camera.

[0063] All calculations were performed using first-principles simulations in the VASP program. The generalized gradient approximation with the Perdew-Burke-Ernzerhof (PBE) exchange-correlation energy was used to describe the electron exchange and correlation potentials, and the plane wave cutoff energy was set to 400 eV.

[0064] Test Example 1: Internal Structure Analysis of PEA2PbBr4 Single Crystal

[0065] In order to reveal the internal structure of the PEA2PbBr4 single crystal of the present invention, this test uses a scanning electron microscope (SEM) and an X-ray diffraction (XRD) instrument to perform structural analysis on the PEA2PbBr4 single crystal. The results are as follows: Figure 2 b~ Figure 2 d. Among them, Figure 2 b and Figure 2c are the (001) top view and (010) cross-sectional SEM images of PEA2PbBr4 single crystal, respectively; Figure 2 d is the powder XRD pattern of PEA2PbBr4 single crystal and theoretical calculation.

[0066] Scanning electron microscopy (SEM) was used to observe the cross-section and surface morphology of the sample, which is a powerful means to reveal its internal structure. It can be observed from the figure that the (010) cross section shows an obvious layered structure (see Figure 2 c), while the (001) surface is composed of irregular flakes (see Figure 2 b), which further confirms that the crystal growth process proceeds in a layer-by-layer manner, which is consistent with the unique layered structure of PEA2PbBr4 crystals formed by the interweaving of organic and inorganic layers.

[0067] Figure 2 The XRD pattern of d shows that the characteristic diffraction peaks (00l) (l = 2, 3, 4, 5, 6, 7) of PEA2PbBr4 crystals all show sharp and strong characteristics, and no impurity peaks are observed. This result fully proves the high crystallinity and high purity of PEA2PbBr4 single crystals. In addition, this test compares the XRD results of PEA2PbBr4 single crystals with the theoretically calculated powder XRD results, further proving the layered structural characteristics of PEA2PbBr4 single crystals (see Figure 2 d).

[0068] Test Example 2: Study on the decay time and penetration depth of PEA2PbBr4 crystals under different excitation sources

[0069] This test example is used to study the decay time and penetration depth of PEA2PbBr4 crystals under different excitation sources (vacuum ultraviolet light, ultraviolet light and X-ray). The decay time summary table and schematic diagram of PEA2PbBr4 crystals under different excitation sources are shown in Table 1 and Table 2, respectively. Figure 4 As shown. Among them, Figure 4 a and Figure 4 b are the summary and curve diagrams of the decay time of PEA2PbBr4 crystals under different excitation sources, respectively. Where Ex represents the excitation wavelength, Em represents the emission peak, and τ represents the decay time.

[0070] Table 1 Summary of decay time of PEA2PbBr4 crystals under different excitation sources

[0071]

[0072] Table 1 and Figure 4Results show that the decay time of PEA2PbBr4 crystals in radioluminescence is approximately tens of nanoseconds, while in photoluminescence, the decay time is shortened to a few nanoseconds. Furthermore, the photoluminescence decay time shows a trend of decreasing with decreasing excitation wavelength. When excited with shorter wavelengths, carriers are more likely to be closer to the crystal surface, thereby increasing sensitivity to surface processes. Therefore, the present inventors speculate that this phenomenon is closely related to the penetration depth of the different wavelengths of excitation light.

[0073] To verify the above speculation, this test further calculated the absorption coefficient of PEA2PbBr4 crystal using VASP to determine the penetration depth of light in the crystal. The results are as follows: Figure 5 As shown. Among them, Figure 5 a is the result diagram of PEA2PbBr4 single crystal absorption coefficient and penetration depth; Figure 5 b is a schematic diagram of the penetration depth of vacuum ultraviolet light, ultraviolet light and X-ray in PEA2PbBr4 single crystal.

[0074] The results show that in the VUV band, the penetration depth of PEA2PbBr4 crystal is extremely small, about 10 to 30 nm from the crystal surface, which is significantly shorter than that of ultraviolet and visible light (such as Figure 5 In addition, since VUV light has a small penetration depth in the crystal, it has a significant effect on the surface of the crystal, while X-rays have high energy and a large penetration depth, so they can excite the interior of the crystal (such as Figure 5 b). Test Example 3: Optical Properties of PEA2PbBr4 Crystals

[0075] This test example is used to study the optical properties of the PEA2PbBr4 crystal of the present invention. Figure 6 The UV-visible transmission spectrum of PEA2PbBr4 single crystal is shown in Figure 2. Figure 6 As shown, the absorption edge of PEA2PbBr4 crystal is located at 425nm.

[0076] Furthermore, this test studies the photoluminescence (PL) spectra of PEA2PbBr4 crystals under different optical configurations. The photoluminescence (PL) spectra of PEA2PbBr4 crystals under 193nm excitation were measured using reflective and transmissive configurations. The results are as follows: Figure 7 As shown. Among them, Figure 7 a is the PL spectrum under 193nm excitation measured under reflective light path, Figure 7 b is the PL spectrum of 193 nm excitation measured under the transmission light path.

[0077] The results show that under reflection measurement, PEA2PbBr4 crystals exhibit a main emission peak at 409nm under 193nm excitation (such as Figure 7In the transmission measurement, the PEA2PbBr4 crystal only shows an emission peak at 435nm, and no emission peak at 409nm (as shown in Figure 7 (b) This is because, in transmission mode detection, the 409nm emission photons generated on the surface are strongly absorbed by the crystal due to self-absorption and cannot reach the detector, while the 435nm emission from the bulk (with energy below the absorption edge) can penetrate the crystal and be detected.

[0078] Figure 8 The results show that the emission peak at 409 nm has a short lifetime of 600 ps, ​​which is attributed to the surface exciton recombination process; while the emission peak at 435 nm has a long decay lifetime of 1.55 ns, which corresponds to the bulk exciton recombination process (see Figure 8 This is because the surface excitons are difficult to utilize due to the self-absorption effect of the PEA2PbBr4 crystal, while the reflective vacuum ultraviolet imaging detection system of the present invention can effectively utilize surface emission.

[0079] Test Example 4: Comparative Analysis of PEA2PbBr4 Crystals and Common Commercial Scintillators

[0080] This test example is used to compare and analyze the scintillator PEA2PbBr4 crystal of the present invention with common commercial scintillators. The results are as follows: Figure 9 As shown. Among them, Figure 9 a is the decay time histogram of PEA2PbBr4 crystal and common scintillators, where Ex represents the excitation wavelength, Em represents the emission peak, and τ represents the decay time; Figure 9 b is a three-dimensional comparison diagram of PLQY, decay time, and emission peak of PEA2PbBr4 crystal and common commercial scintillators sodium salicylate and YAG:Ce.

[0081] The results show that the decay time of most commercial scintillators is in the microsecond and nanosecond range, while picosecond scintillators are relatively rare. The decay time of PEA2PbBr4 is only 600ps, which is 5 orders of magnitude faster than Cs3Cu2I5 (1.92μs) and nearly 6 times faster than the currently promising CsPbBr3 (3.4ns) perovskite scintillator (e.g. Figure 9(a). Therefore, PEA2PbBr4 offers significant advantages over the decay times of commercial VUV scintillators sodium salicylate (10ns) and YAG:Ce (70ns). Because traditional scintillators typically have long decay times, often in the microsecond range, these scintillators are often accompanied by a significant "tailing" effect, extending the signal duration and thus affecting the resolution of subsequent events. The ultrafast decay time of PEA2PbBr4 provides higher temporal resolution, which is crucial for accurately capturing and analyzing transient events.

[0082] In addition, the PLQY values ​​of PEA2PbBr4, sodium salicylate and YAG:Ce are 32.1%, 40.2% and 50.7%, respectively (e.g. Figure 9 (b). Although the PLQY value of PEA2PbBr4 is slightly lower than that of commercial materials, its single crystal PLQY is higher than that of many perovskite single crystals, such as CsCu2I3 single crystal (PLQY = 15.7%). This shows that the PEA2PbBr4 crystal of the present invention exhibits excellent potential in terms of luminous efficiency and fast response time, providing strong support for its application in high-performance detection systems.

[0083] Test Example 5: Scintillation Performance and Imaging Test of Vacuum Ultraviolet Imaging Detector at Low Temperature

[0084] In actual vacuum ultraviolet detection missions, the space environment is extremely cold, with temperatures dropping to below -10°C or even lower. Therefore, the scintillator materials used for vacuum ultraviolet detection must have excellent low-temperature tolerance and low-temperature optical property stability to meet stringent detection requirements. To this end, this test conducted a time-resolved photoluminescence (TRPL) test on the PEA2PbBr4 crystal in the temperature range of 77K to 300K to verify its scintillation performance under low-temperature conditions. The results are as follows: Figure 10 shown.

[0085] in, Figure 10 a is the temperature-dependent TRPL-Mapping diagram at 409 nm; Figure 10 b is the decay time variation of the 409 nm emission peak with temperature; Figure 10 c is an image of an airplane, a puppy, flowers, and leaves under the reflective light path configuration of Example 1, and the illustration is a mask.

[0086] like Figure 10 a and Figure 10As shown in Figure 2b, the 409nm emission peak exhibited extremely fast decay times at different temperatures. By fitting an exponential decay function, the decay times corresponding to each temperature point were obtained in this test, and they were all very stable. This result shows that the PEA2PbBr4 crystal is less sensitive to temperature changes and exhibits excellent fluorescence stability. It can be seen that the PEA2PbBr4 crystal of the present invention has relatively consistent fluorescence behavior at different temperatures, showing great superiority in vacuum ultraviolet scintillator applications.

[0087] However, PEA2PbBr4 crystals still have a key problem - the self-absorption effect, which limits the effective use of surface excitons in actual VUV detection. Therefore, the present invention constructs the reflective optical path configuration of Example 1. This configuration can utilize the surface exciton recombination effect of PEA2PbBr4 crystals to effectively reduce the impact of self-absorption, thereby achieving ultrafast VUV scintillation imaging. Using this reflective optical path configuration, the present invention successfully captured clear images of airplanes, puppies, flowers and leaves (such as Figure 10 c). In a dark environment, these images clearly display the outlines and detailed features of each shape, fully demonstrating the prepared PEA2PbBr4 crystal's ability to identify complex targets and quickly restore the display. The image resolution is highly consistent with the object's shape, indicating the high fidelity of this imaging system and its potential application in vacuum ultraviolet imaging. Therefore, by constructing a reflective optical imaging system for VUV light, the present invention successfully achieves clear imaging with PEA2PbBr4 single crystal scintillator, fully demonstrating its great potential in the field of scintillation imaging.

[0088] In summary, the present invention cleverly exploits the rapid recombination of excitons on the surface of layered perovskite PEA2PbBr4 crystals to achieve ultrafast VUV reflective scintillation with a decay time of 600 ps. By constructing a reflective optical path configuration, the present invention successfully demonstrates its capabilities in VUV scintillation imaging. This invention not only provides a new solution for reducing the impact of self-absorption in perovskite scintillators but also bridges the gap between perovskite scintillators and practical applications in ultrafast VUV detection, paving a new path for the application of perovskite materials in VUV imaging.

[0089] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the application should be included in the scope of protection of the present application.

Claims

1. A reflective ultrafast scintillation vacuum ultraviolet imaging detection system, characterized in that: The optical system comprises an optical path system, a detection and recording component, and a structural support component. The optical path system is a reflective optical path configuration. A secondary mirror (2), a primary mirror (1), an integrated filter (4), and a vacuum ultraviolet scintillator (5) are sequentially arranged in front and behind the optical path system. The optical path system is further provided with a correction lens (3), the diameter of the correction lens (3) being larger than the diameter of the secondary mirror (2), and the correction lens (3) being sleeve-connected to the secondary mirror (2) or being located at the front end of the optical path system; The primary mirror (1) is a concave lens, and the secondary mirror (2) is a convex lens. The material of the vacuum ultraviolet scintillator (5) is PEA2PbBr4 crystal or BA2PbBr4 crystal.

2. The reflective ultrafast scintillation vacuum ultraviolet imaging detection system according to claim 1, characterized in that: A hollow sleeve is inserted through the middle of the primary mirror (1), and the integrated filter (4) is installed at the rear end of the hollow sleeve.

3. The reflective ultrafast scintillation vacuum ultraviolet imaging detection system according to claim 1, characterized in that: The integrated filter (4) consists of an outer protective layer, a metal reflection layer, a multilayer interference film, an absorption layer and a VUV transmission substrate.

4. The reflective ultrafast scintillation vacuum ultraviolet imaging detection system according to claim 3, characterized in that: The outer protective layer material of the integrated filter (4) is ultra-thin Si3N4; the material of the metal reflection layer is aluminum thin film; the multilayer interference film is Si / Mo alternating layers; the material of the absorption layer is carbon thin film; and the VUV transmission substrate is a LiF window.

5. The reflective ultrafast scintillation vacuum ultraviolet imaging detection system according to claim 4, characterized in that: The thickness of the ultra-thin Si3N4 is less than 10nm; the thickness of the aluminum film is 40-60nm; the total thickness of the Si / Mo alternating layer is 400-600nm; the thickness of the carbon film is 15-25nm; and the thickness of the LiF window is 1-2mm.

6. The reflective ultrafast scintillation vacuum ultraviolet imaging detection system according to claim 1, characterized in that: The detection and recording component is a charge coupled device (6), and the structural support component is a lens barrel (7).

7. The reflective ultrafast scintillation vacuum ultraviolet imaging detection system according to claim 1, characterized in that: The preparation method of the PEA2PbBr4 or BA2PbBr4 crystal of the vacuum ultraviolet scintillator (5) comprises the following steps: Step S1, dissolving phenylethylamine hydrobromide or butylammonium bromide: lead bromide in a stoichiometric ratio of 2:1 in N,N-dimethylformamide solvent, stirring, heating, and then filtering to obtain a polycrystalline material and a transparent saturated precursor solution 1; Step S2, dissolving the polycrystalline material in N,N-dimethylformamide to obtain a new saturated precursor solution 2, and evaporating and crystallizing the precursor solution 1 at room temperature to obtain transparent PEA2PbBr4 or BA2PbBr4 seed crystals; Step S3: adding seed crystals to the precursor solution 2 and slowly evaporating and further growing to obtain PEA2PbBr4 or BA2PbBr4 crystals.

8. The reflective ultrafast scintillation vacuum ultraviolet imaging detection system according to claim 7, characterized in that: In step S1 of the method for preparing PEA2PbBr4 or BA2PbBr4 crystals, after stirring and heating at a temperature of 50 to 80°C for 20 to 30 hours, the polycrystalline material and the transparent saturated precursor solution 1 are obtained by filtration.

9. The reflective ultrafast scintillation vacuum ultraviolet imaging detection system according to claim 7, characterized in that: In step S3 of the method for preparing PEA2PbBr4 or BA2PbBr4 crystals, slow evaporation is performed at a temperature of 20 to 40° C. for 60 to 84 hours to further grow the PEA2PbBr4 or BA2PbBr4 crystals.

10. The detection method of the reflective ultrafast scintillation vacuum ultraviolet imaging detection system according to any one of claims 1 to 9, characterized in that: The light is processed by a reflective optical path configuration of an optical path system, comprising the following steps: after being corrected by a correction lens (3), the light is reflected by a concave lens of a primary mirror (1), and the optical path is adjusted by the converging action of a convex lens of a secondary mirror (2), and then vacuum ultraviolet light with a wavelength range of 10 to 200 nm is filtered by an integrated filter (4) to pass through, and the filtered vacuum ultraviolet light forms a clear image on a vacuum ultraviolet scintillator (5); the optical signal processed by the optical path system is converted into an electrical signal by a detection and recording component and stored and transmitted.

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