Glass-ceramic material for broadband solar-blind ultraviolet photodetector and preparation method thereof

Abstract

This invention relates to the field of solar-blind ultraviolet photodetector technology, specifically to a glass-ceramic material and its preparation method for a broadband solar-blind ultraviolet photodetector. The glass-ceramic material is prepared by externally doping TbF3 into a fluorine-oxygen microcrystalline glass matrix. The matrix glass contains 60-80% SiO2, 10-20% KF, and 10-25% ZnF2 by molar percentage. The TbF3 doping amount is 0.5-10% of the total molar amount of each raw material in the matrix glass. When used as a solar-blind ultraviolet photodetector, this material exhibits a significant photoelectric response in the 188-400 nm ultraviolet range, possessing a broadband response range, high sensitivity, high luminous intensity, high quantum efficiency, high stability, and high signal-to-noise ratio.

Description

Technical Field

[0001] This invention relates to the field of solar blind ultraviolet photodetector technology, specifically to a glass-ceramic material and its preparation method for a broadband solar blind ultraviolet photodetector. Background Technology

[0002] Ultraviolet (UV) radiation is the strongest form of radiation found in nature, with a wavelength range of 200nm to 400nm. Based on wavelength, it can be divided into three bands: UVA (400nm-320nm), UVB (320nm-290nm), and UVC (280nm-200nm). The solar-blind UV band is the 200nm-280nm band. In this band, sunlight is strongly absorbed by the ozone layer as it passes through the Earth's atmosphere, essentially preventing it from reaching the ground. Therefore, within a certain altitude range from the Earth's surface, the UV band is generally absent. However, in practical applications, UV light is emitted in certain situations, such as during the operation of missiles, aircraft, ships, and vehicles. These vehicles themselves generate sources of radiation such as flames, electric arcs, and UV beacons. Alternatively, when a target object has a UV light source, a detector can accurately detect this UV light, enabling precise location and real-time tracking of the signal source.

[0003] Currently, the detection of infrared and ultraviolet (UV) wavelengths beyond the visible light spectrum has become a focus of increasing research. Compared to infrared detection, UV detection avoids interference from natural light and has the advantages of small size and light weight, which greatly improves the cost and performance of UV detection systems. Furthermore, the low sensitivity of a range of detectors to visible and infrared light ensures powerful measurement capabilities even with minimal UV background. Solar-blind ultraviolet light, namely far-ultraviolet and vacuum ultraviolet light with wavelengths less than 0.28 μm, is strongly absorbed by atmospheric ozone and water vapor and cannot penetrate the atmosphere to reach the Earth's surface. This band has low background noise and is almost unaffected by solar radiation in near-Earth space. Therefore, photodetectors operating in this spectral range have advantages such as low noise, anti-interference, and high sensitivity, and have wide application value in military, communications, and civilian fields such as flame sensing, ultraviolet communication, ozone detection, and missile attack early warning. Therefore, following infrared detection technology, ultraviolet detection, especially solar-blind ultraviolet detection technology, is a dual-use detection technology for both military and civilian applications and is also a very useful detection technology for near-Earth space research.

[0004] In existing research, solar-blind ultraviolet detection devices mainly include photomultiplier tubes, wide-bandgap semiconductors, and infinitesimal perovskite quantum dots. However, each of these three techniques has its own obvious shortcomings.

[0005] Detectors containing photomultiplier tubes are traditionally used detectors, offering high sensitivity, but they are large, consume a lot of energy, and have low quantum efficiency. Detectors containing wide-bandgap semiconductors are currently the most widely used, offering good thermal conductivity, high electron drift saturation velocity, and chemical stability, but their fabrication process is complex and requires advanced technology. Quantum dot-based detectors have strong absorption capabilities for ultraviolet light, but current solar-blind ultraviolet detectors based on quantum dots often use toxic elements as raw materials, posing safety risks.

[0006] The current shortcomings of solar-blind ultraviolet detectors include small detection range, low quantum efficiency, toxic raw materials, and complex manufacturing process. These are mainly due to problems with the materials used. Therefore, it is necessary to make corresponding improvements to address the shortcomings of current detectors and develop a new material to meet the needs of solar-blind ultraviolet detectors. Summary of the Invention

[0007] The purpose of this invention is to solve the technical problems existing in different types of solar-blind ultraviolet detectors, and to provide a glass-ceramic material for a broadband solar-blind ultraviolet photodetector, along with a corresponding preparation method.

[0008] To achieve the above objectives, the present invention specifically adopts the following technical solution:

[0009] A glass-ceramic material for a broadband solar-blind ultraviolet photodetector is disclosed. The glass-ceramic material is prepared by incorporating TbF3 into the matrix glass as an external doping agent. The matrix glass contains 60-80% SiO2, 10-20% KF, and 10-25% ZnF2 by molar percentage. The amount of TbF3 incorporated is 0.5-10% of the total molar amount of each raw material in the matrix glass.

[0010] Furthermore, the SiO2 content is 65-70%.

[0011] Furthermore, the KF content is 14-16%.

[0012] Furthermore, the ZnF2 content is 14-17%.

[0013] Furthermore, the substrate glass contains 70% SiO2, 15% KF and 15% ZnF2.

[0014] Furthermore, the amount of TbF3 incorporated is 5% of the total molar amount of all raw materials in the matrix glass, expressed as a molar percentage.

[0015] The above-mentioned method for preparing glass-ceramic materials specifically includes the following steps:

[0016] (1) First, weigh SiO2, ZnF2 and KF according to the molar ratio of the matrix glass. The molar ratios of SiO2, ZnF2 and KF are 60-80% SiO2, 10-20% KF and 10-25% ZnF2, respectively. Then, weigh TbF3 according to the total molar amount of these three, with TbF3 being 0.5-10% of the total molar amount of the first three.

[0017] (2) Put the raw materials in step (1) into a porcelain mortar and mix them thoroughly to form a uniform mixture. Then put it into a covered alumina crucible and melt it in a muffle furnace at a temperature of 1550-X℃ and keep it warm for 30 minutes. Stir slowly (10 revolutions per minute) for 30 minutes, keep it warm for 1 hour, and then cool it down to 1250℃ to discharge the material.

[0018] (3) Pour the melt obtained in step (2) onto a cold brass plate mold and press it with another brass sheet to prepare the precursor glass;

[0019] (4) Finally, the precursor glass prepared in step (3) is annealed to obtain the final product glass-ceramic material.

[0020] Furthermore, the annealing process in step (4) specifically involves heat-treating the precursor glass at 540-560°C for 10 hours.

[0021] Glass-ceramic materials are used in broadband solar blind ultraviolet photodetectors.

[0022] A solar-blind ultraviolet photodetector was fabricated using the aforementioned glass-ceramic material as the down-conversion optics.

[0023] Addressing the current limitations of solar-blindness detection devices, such as small detection range, low quantum efficiency, toxic raw materials, and complex fabrication processes, this invention utilizes rare-earth ion-doped microcrystalline glass as a downconversion material to effectively improve these issues. The aim is to fill gaps and improve upon existing materials to develop a more efficient solar-blindness detection device. Based on the abundant energy levels and stable physicochemical properties of rare-earth ions, rare-earth ion-doped downconversion materials are a novel type of photoelectric detector and converter developed in recent years. The rare-earth ion-doped downconversion layer is mainly achieved by combining it with ordinary semiconductors and modulating broadband solar-blind ultraviolet light, thereby enabling ordinary semiconductors to respond to broadband solar-blind ultraviolet light.

[0024] Selecting efficient detector core materials is crucial for developing solar-blind ultraviolet detector applications. Fluoride-coated transparent glass-ceramics (GC), as a type of inorganic material, have become promising candidates for laser and detection applications in the ultraviolet (UV) and vacuum ultraviolet (VUV) wavelength ranges due to their unique characteristics of low phonon energy, high transmittance, and high RE ion density. They also retain the advantages of high mechanical strength, chemical durability, and thermal stability found in oxide glasses.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] This invention uses a melt-quenching method to prepare a glass-ceramic material for a broadband solar-blind ultraviolet photodetector. When used as a solar-blind ultraviolet photodetector, this material exhibits a significant photoelectric response in the ultraviolet light range of 188-400 nm, and has a broadband response range, high sensitivity, high luminous intensity, high quantum efficiency, high stability and high signal-to-noise ratio.

[0027] The glass-ceramic material involved in this invention uses readily available and non-toxic raw materials, requires minimal equipment, and has a simple and time-saving preparation process. Attached Figure Description

[0028] Figure 1 This is a flowchart of the preparation process of the present invention.

[0029] Figure 2 It is 5% Tb in Example 6 3+ A schematic diagram of a broadband solar blind ultraviolet detector made of doped microcrystalline glass.

[0030] Figure 3 Specifically:

[0031] (A) 5% Tb in Example 6 3+ XRD image of doped glass-ceramics;

[0032] (B) 5% Tb in Example 6 3+ EDS image of doped glass-ceramics;

[0033] (C) 5% Tb in Example 6 3+ EDS mapping mode of doped microcrystalline glass;

[0034] (D) Transmission electron microscope image;

[0035] (E) High-resolution transmission electron microscopy image; 5% Tb in Example 6 3+ SAED image of doped glass-ceramics;

[0036] (F) is the DSC curve of the glass-ceramic sample at a heating rate of 1℃ / min;

[0037] (G) Raman spectroscopy analysis was performed on the glass sample.

[0038] Figure 4 Specifically:

[0039] (A) 5% Tb in Example 6 3+ Excitation spectrum of doped glass-ceramics;

[0040] (BD) Emission spectrum under 371 nm excitation;

[0041] (E) shows 5% Tb in Example 6. 3+ Absorption spectrum of doped glass-ceramics;

[0042] (F) shows 5% Tb in Example 6. 3+ Transmission spectrum of doped microcrystalline glass.

[0043] Figure 5 Specifically, it refers to: (A)-(I) 5% Tb in Example 6 3+ Photoluminescence spectra of doped glass-ceramic samples at different excitation wavelengths.

[0044] Figure 6 Specifically: (A)-(F) are based on 5% Tb in Example 6. 3+ IV characteristics of photon trapping devices based on doped glass-ceramic samples.

[0045] Figure 7 Specifically:

[0046] (AG) Example 6: Photoelectric response under 188-200nm pulsed ultraviolet light irradiation;

[0047] (HI) 5% Tb 3+ Photoelectric response of ion-doped glass before and after heat treatment and under 230 nm and 259 nm ultraviolet light in the dark;

[0048] (JR) Example 6: Photoelectric response under 200-280nm pulsed ultraviolet light irradiation.

[0049] Figure 8 Contains different Tb 3+ Transmission spectra of glass-ceramics at different concentrations are shown in the attached images, which are photographs of the corresponding glass-ceramic samples.

[0050] Figure 9 It is 5.0Tb in Example 6 3+ Comparison of emission spectra of doped microcrystalline glass after heat treatment at 540℃ for different times.

[0051] Figure 10 Example 6 compares the transmission spectra of microcrystalline glass and glass materials at different temperatures.

[0052] Figure 11 The KTb2F7 microcrystalline glass in Example 6 and the Tb in Comparative Example 5 3+ Comparison of emission spectra of NaYF4-doped microcrystalline glass.

[0053] Figure 12 It is the KTb2F7 microcrystalline glass in Example 6 and the Tb in Comparative Example 5 3+ Tb in NaYF4 microcrystalline glass 3+ Comparison of quantum yield values ​​for emission.

[0054] Figure 13 It is the KTb2F7 microcrystalline glass in Example 6 and the Tb in Comparative Example 5. 3+ Comparison of transmission spectra of NaYF4-doped glass-ceramics. The attached figure shows photographs of glass-ceramics (left: KTb2F7 glass-ceramics, right: NaYF4 glass-ceramics).

[0055] Figure 14 This is a schematic diagram of the crystallization mechanism of KTb2F7 microcrystalline glass and traditional microcrystalline glass in Example 6. Implementation

[0056] The representative embodiments shown in the accompanying drawings will now be further refined. It should be understood that the following description is not intended to limit the embodiments to a single preferred embodiment. Rather, it is intended to cover alternatives, modifications, and equivalents that may be included within the substance and scope of the embodiments defined by the appended claims.

[0057] Example 1: In view of the shortcomings of current materials for preparing solar-blind ultraviolet photodetectors, the inventors prepared a glass-ceramic material for broadband solar-blind ultraviolet photodetectors.

[0058] (1) First, based on a total weight of 30g, weigh SiO2, ZnF2 and KF according to the molar ratio of the matrix glass. The molar ratios of SiO2, ZnF2 and KF are 70% SiO2, 15% KF and 15% ZnF2, respectively. Then, weigh TbF3 based on the total molar weight of these three components. The molar percentage of TbF3 is 0.1% of the total molar weight of the first three components.

[0059] (2) Put the raw materials in step (1) into a porcelain mortar and mix them thoroughly to form a uniform mixture. Then put it into a covered alumina crucible and melt it in a muffle furnace at 1550°C and keep it warm for 30 minutes. Stir slowly (10 revolutions per minute) for 30 minutes, keep it warm for 1 hour, and then cool it down to 1250°C to discharge the material.

[0060] (3) Pour the melt obtained in step (2) onto a cold brass plate mold and press it into shape with another brass sheet to prepare the precursor glass;

[0061] (4) Finally, the precursor glass prepared in step (3) is annealed at 540°C for 10 hours to obtain the final product glass-ceramic material.

[0062] Example 2:

[0063] Unlike Example 1, the molar percentage of TbF3 is 0.5% of the total molar amount of the first three components.

[0064] Example 3:

[0065] Unlike Example 1, TbF3 is 2.0% of the total molar percentage of the first three components.

[0066] Example 4:

[0067] Unlike Example 1, TbF3 is 3.0% of the total molar percentage of the first three components.

[0068] Example 5:

[0069] Unlike Example 1, TbF3 is 4.0% of the total molar percentage of the first three components.

[0070] Example 6:

[0071] Unlike Example 1, TbF3 is 5.0% of the total molar percentage of the first three components.

[0072] Example 7:

[0073] Unlike Example 1, TbF3 is 10% of the total molar percentage of the first three components.

[0074] Comparative Example 1:

[0075] Unlike implementation 1, it is undoped with TbF3.

[0076] Figure 8 As shown, Tb 3+ The diffraction peaks of doped glass-ceramics are wider than those of undoped glass-ceramics, indicating that Tb 3+ The crystal size of doped glass-ceramics is smaller than that of undoped glass-ceramics. The results show that Tb... 3+ The transmittance of doped microcrystalline glass is higher than that of undoped microcrystalline glass.

[0077] like Figure 4 (C) shows different Tb values. 3+The emission spectra of the doped samples under 371 nm excitation show that the 5 mol% glass sample has the strongest emission intensity.

[0078] like Figure 4 (D) shows different Tb values. 3+ The emission spectrum of the doped glass-ceramic sample under 371 nm excitation, 5% Tb 3+ The doped glass exhibits the strongest luminescence intensity before and after heat treatment. This confirms that the glass-ceramic sample is transparent and emits strong green light under ultraviolet excitation, capable of converting ultraviolet light into visible light, demonstrating strong spectral conversion capabilities.

[0079] Comparative Example 2:

[0080] The difference from Example 6 is that the annealing heat treatment time is different.

[0081] Figure 9 The results show that under 371 nm light excitation, the spectrum of the glass-ceramic exhibits a strong emission peak near 544 nm. With increasing heat treatment time from 5 to 10 h, emission is enhanced due to crystal precipitation within the glass-ceramic. When the heating time is further extended to 15 h, excessive crystal precipitation occurs, leading to insufficient ion spacing, resulting in concentration quenching of the luminescence and subsequent decrease in emission intensity.

[0082] Comparative Example 3: Unlike Example 6, the annealing heat treatment temperature was different.

[0083] Figure 10 The results show that the transmittance of the microcrystalline glass after heat treatment at 540℃ is as high as 90% at 544 nm. However, when the heat treatment temperature is increased to 550℃, the transmittance decreases significantly due to the increase in grain size, and scattering becomes severe.

[0084] Comparative Example 4:

[0085] Unlike Example 6, this one did not undergo annealing heat treatment.

[0086] Figure 3 The results of Example 6 show that the glass-ceramic sample only precipitates KTb2F7 nanocrystals. SAED mode reveals highly dispersed points and rings with varying brightness, indicating that the glass-ceramic possesses a polycrystalline structure, good thermal stability, and crystallization stability. Furthermore, the nanoparticles are uniformly distributed, with O, Tb, Si, Zn, K, and F elements evenly distributed.

[0087] like Figure 4 (B) shows the emission spectra of the samples of Example 6 and Comparative Example 2 under 371 nm excitation; the comparison shows that the microcrystalline glass has a stronger emission intensity than the precursor glass.

[0088] Figure 5This indicates that the microcrystalline glass sample of Example 6 reaches a fourth peak near 372 nm in the 360 ​​nm - 382 nm range. These trends are consistent with... Figure 4 (A) The excitation spectra of the fluorine-oxygen glass samples are consistent. There are four relatively obvious emission peaks in the range of 400-700 nm, corresponding to the transition of Tb3+ ions from the 5D4 state to the 7FJ (J = 6,5,4,3) state.

[0089] Figure 6 The results show that all IV characteristic curves of the glass-ceramic sample in Example 6 exhibit a perfect linear positive correlation, consistent with Ohm's law. The current signal is minimal in darkness, and the curves overlap in the 196-200 nm range, indicating that the current remains almost unchanged with increasing wavelength. The current reaches its maximum value around 372 nm. These results are consistent with the previous analysis of the sample's optical properties.

[0090] Figure 7 The results show that the microcrystalline glass sample in Example 6 exhibits a large photoelectric response under ultraviolet light irradiation, proving that the optical signal can be effectively converted into an electrical signal. The ultraviolet detector of this invention shows a significant photoelectric response starting from 188 nm, possessing characteristics of a wide response range, high sensitivity, high stability, and high signal-to-noise ratio. This indicates that the glass material we designed is a promising candidate material for solar-blind ultraviolet photodetectors.

[0091] The table below compares the detection ranges of different solar-blind ultraviolet detectors, showing that the detection range of this invention is higher than that of other detectors.

[0092] .

[0093] Comparative Example 5:

[0094] The difference from Example 6 is:

[0095] (1) First, based on a total of 30g, SiO2, Na2O, Al2O3 and NaF are weighed according to the molar ratio of the matrix glass. The molar ratios of SiO2, Na2O, Al2O3, NaF and YF3 are 40% SiO2, 18% Na2O, 25% Al2O3, 7% NaF and 10% YF3, respectively.

[0096] (2) Put the raw materials in step (1) into a porcelain mortar and mix them thoroughly to form a uniform mixture. Then put it into a covered alumina crucible and melt it in a muffle furnace at 1550°C and keep it warm for 30 minutes. Stir slowly (10 revolutions per minute) for 30 minutes, keep it warm for 1 hour, and then cool it down to 1250°C to discharge the material.

[0097] (3) Pour the melt obtained in step (2) onto a cold brass plate mold and press it into shape with another brass sheet to prepare the precursor glass;

[0098] (4) Finally, the precursor glass prepared in step (3) is annealed at 600°C for 10 hours to obtain the final product glass-ceramic material.

[0099] Since the NaYF4 microcrystalline glass prepared in Comparative Example 5 is a recognized excellent matrix, the high luminescence intensity, high quantum efficiency, high transmittance and controllable crystallization of the present invention are demonstrated by comparing it with the KTb2F7 microcrystalline glass of the present invention.

[0100] Figure 11 This indicates that Tb was observed in the microcrystalline glass spectrum under 371 nm light excitation. 3+ The emission intensity of KTb2F7 microcrystalline glass is higher than that of NaYF4 microcrystalline glass, which is due to the Tb... 3+ Controllable doping in fluoride crystals.

[0101] Figure 12 This indicates that Tb in KTb2F7 glass-ceramics 3+ The quantum yield is as high as 70.08%. And Tb 3+ The quantum yield of the NaYF4-doped glass-ceramic was 40.20%. These results indicate that the glass-ceramic we designed is a more efficient Tb-doped glass. 3+ Launching material.

[0102] Figure 13 This indicates that KTb2F7 glass-ceramics have high transmittance in the visible light region, far exceeding that of Tb. 3 Doped NaYF4 glass-ceramics. In traditional NaYF4 glass-ceramics, a large number of crystals are deposited in the GC, resulting in severe scattering and low transmittance. NaYF4 glass-ceramics are almost opaque. Therefore, our designed glass-ceramic is more transparent than traditional NaYF4GC.

[0103] Figure 14 This indicates that in traditional fluorine-oxygen glass, adding a large amount of Ln(Ln=Y, Lu, Gd, La)F3 to the glass precipitates NaLn(Ln=Y, Lu, Gd)F4, LaF3, YF3 crystals, etc. [] Then rare earth (RE) ions pass through Y... 3+ Lu 3 + , Gd 3+ Or La 3+The ion substitution process enters the crystal structure of these fluorides. In fact, in traditional fluoride glasses, due to the severe mismatch in ionic radii between RE ions and substituted ions, the binding of RE ions in the crystal structure is uncontrollable. Large amounts of fluoride crystals are not accommodated by RE ions and precipitate. In our glass-ceramic, the crystallization of KTb₂F₇ is entirely controlled by a small amount of doped RE ions, which are an integral part of the crystal. During the crystallization process of the glass-ceramic, Tb… 3+ It spontaneously integrates into fluoride crystals without undergoing ion substitution. The number of crystals in glass-ceramics is very small, and the incorporation of RE ions into the crystal structure is controllable.

[0104] For ease of explanation, specific naming has been used in the above description to provide a thorough understanding of the described embodiments. However, it will be apparent to those skilled in the art that these specific details are not required to implement the above embodiments. Therefore, the above description of the specific embodiments described herein is presented for illustrative and descriptive purposes. Its purpose is not to exhaustively list or limit the embodiments to the specific, precise forms disclosed. It will be apparent to those skilled in the art that certain modifications, combinations, and variations can be made based on the above teachings.

Claims

1. A glass-ceramic material for broadband solar-blind UV photodetectors, characterized in that: The glass-ceramic material is prepared by incorporating TbF3 into the fluorine-oxygen microcrystalline glass as the matrix glass through external doping. The matrix glass contains 60-80% SiO2, 10-20% KF and 10-25% ZnF2 by molar percentage. The amount of TbF3 incorporated is 0.5-10% of the total molar amount of each raw material in the matrix glass by molar percentage.

2. The glass-ceramic material for broadband solar-blind UV photodetectors according to claim 1, characterized in that: The SiO2 content is 65-70%.

3. The glass-ceramic material for broadband solar blind ultraviolet photodetectors according to claim 1, characterized in that: The KF content is 14-16%.

4. The glass-ceramic material for broadband solar blind ultraviolet photodetectors according to claim 1, characterized in that: The ZnF2 content is 14-17%.

5. The glass-ceramic material for broadband solar-blind UV photodetectors according to claim 1 or 2 or 3 or 4, characterized in that: The substrate glass contains 70% SiO2, 15% KF and 15% ZnF2.

6. The glass-ceramic material for broadband solar-blind UV photodetectors according to claim 5, characterized in that: The amount of TbF3 incorporated is 5% of the total molar amount of all raw materials in the matrix glass, expressed as a molar percentage.

7. The method for preparing the glass-ceramic material according to any one of claims 1-5, characterized in that: Specifically, the following steps are included: (1) First, weigh SiO2, ZnF2 and KF according to the molar ratio of the matrix glass. The molar ratios of SiO2, ZnF2 and KF are 60-80% SiO2, 10-20% KF and 10-25% ZnF2, respectively. Then, weigh TbF3 according to the total molar amount of these three, with TbF3 being 0.5-10% of the total molar amount of the first three. (2) Put the raw materials in step (1) into a porcelain mortar and mix them thoroughly to form a uniform mixture. Then put it into a covered alumina crucible and melt it in a muffle furnace at a temperature of 1550-1560℃ and keep it warm for 30 minutes. Stir slowly for 30 minutes, keep it warm for 1 hour, and then cool it down to 1250℃ to discharge the material. (3) Pour the melt obtained in step (2) onto a cold brass plate mold and press it with another brass sheet to prepare the precursor glass; (4) Finally, the precursor glass prepared in step (3) is annealed to obtain the final product glass-ceramic material.

8. The method of claim 7, wherein: The annealing process in step (4) is as follows: heat-treat the precursor glass at 540-560℃ for more than 10 hours.

9. The application of the glass-ceramic material according to any one of claims 1-5 in broadband solar-blind ultraviolet photodetectors.

10. A solar-blind ultraviolet photodetector made of glass-ceramic material for a broadband solar-blind ultraviolet photodetector as described in any one of claims 1-6.

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