A chromium-doped ultra-wideband near-infrared fluorescent material and a preparation method thereof
By preparing chromium-doped ultrawideband near-infrared fluorescent materials, the problems of narrow spectrum and high cost in existing technologies have been solved, and broadband near-infrared emission has been achieved, which is suitable for near-infrared phosphor conversion LEDs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- JIANGSU UNIV OF SCI & TECH
- Filing Date
- 2024-03-04
- Publication Date
- 2026-06-26
AI Technical Summary
Existing near-infrared light sources suffer from narrow spectra, poor tunability, high costs, and significant technological barriers, making it difficult to meet the application requirements of broadband near-infrared spectral emission. Furthermore, the variety of near-infrared phosphor materials is limited, making it difficult to achieve effective NIR-II band emission.
Using chromium-doped ultrawideband near-infrared fluorescent materials, a solid-state reaction method was employed to prepare the material. By combining activation ion doping and cation solid solution substitution strategies, the crystal field intensity of the phosphor was controlled to achieve broadband near-infrared luminescence performance. The material emitted NIR-I and NIR-II region spectra under blue light excitation.
Broadband emission under blue light excitation was achieved, with the emission spectrum covering the NIR-I and NIR-II regions. The spectrum is tunable, the preparation method is simple and highly reproducible, and it is suitable for near-infrared phosphor conversion LEDs.
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Figure CN118206991B_ABST
Abstract
Description
Technical Field
[0001] This invention pertains to fluorescent materials and their preparation methods, specifically a chromium-doped ultrawideband near-infrared fluorescent material and its preparation method. Background Technology
[0002] Near-infrared (NIR) light sources play a crucial role in NIR spectroscopy technology. Their ability to rapidly and non-destructively penetrate biological tissues makes them applicable to fields such as night vision, food inspection, water quality testing, biomedical imaging, fiber optic communication, environmental monitoring, and machine vision. In recent years, they have attracted significant attention from researchers and become a focus of international research. However, current NIR semiconductor chips on the market suffer from problems such as narrow spectral width (FWHM < 40nm), poor tunability, high cost, and technological barriers, making it difficult to meet the needs of applications requiring broadband NIR emission. Composite packaging of multiple NIR chips with different emission bands presents challenges such as high technical implementation difficulty, complex and uncontrollable processes, high costs, and poor performance stability, limiting the application and widespread adoption of NIR light sources.
[0003] Near-infrared phosphor-converted LEDs are a novel type of near-infrared light source. They can be pumped using mature blue / visible light chips and possess a series of advantages, including simple manufacturing processes, low cost, low power consumption, small size, portability, and tunable broadband emission, thus attracting widespread attention in the industry. Near-infrared phosphors are one of the key materials for this type of LED device, directly determining its luminous efficiency, spectral continuity, and application scenarios. Currently, research on near-infrared phosphors is still in its early stages, with a shortage of material types and narrow emission spectra (typically within the range of 80–240 nm), while broadband near-infrared phosphor materials are severely lacking. Since the autofluorescence emitted by biological tissues is mainly concentrated in the visible light region and the shorter wavelength range of NIR-I (760–900 nm), and the background interference caused by autofluorescence in biological tissues decreases significantly with increasing wavelength, the in vivo near-infrared II (1000–1700 nm) fluorescence bioimaging effect is excellent, making it an ideal band for applications such as food detection, water quality detection, and biomedical imaging. However, developing near-infrared phosphors that can be effectively excited by commercial ultraviolet or blue light chips and can continuously cover the NIR-II band or even wider emission remains a challenge. Summary of the Invention
[0004] Purpose of the invention: In order to overcome the shortcomings of the prior art, the purpose of this invention is to provide a method for preparing chromium-doped ultrawideband near-infrared fluorescent materials with an emission bandwidth including the NIR-I and NIR-II regions, which can be effectively excited by commercial blue LED chips and has adjustable bandwidth. Another purpose of this invention is to provide a simple, convenient, highly reproducible method for preparing chromium-doped ultrawideband near-infrared fluorescent materials with stable product quality.
[0005] Technical solution: The present invention relates to a chromium-doped ultrawideband near-infrared fluorescent material with the general chemical formula: Sc 2- x A x Si2O7:yCr M Where A is one or more of the elements Y, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Ga, 0 ≤ x ≤ 0.5, 0.001 ≤ y ≤ 0.3, and M is one or more of 3+ and 4+.
[0006] Furthermore, the range of x is 0 ≤ x ≤ 0.3, and the range of y is 0.005 ≤ y ≤ 0.3. Preferably, 0.005 ≤ y ≤ 0.15.
[0007] Furthermore, the emission spectrum of near-infrared fluorescent materials has a full width at half maximum (FWHM) greater than 330 nm, reaching 333–562 nm.
[0008] Furthermore, the products exhibit a single emission peak around 1260 nm when y ≥ 0.03, and the samples all contain Cr. 4+ Cr was found in samples with y = 0.001 to 0.01. 3+ And the higher the concentration, the less.
[0009] The preparation method of the above-mentioned chromium-doped ultrawideband near-infrared fluorescent material includes the following steps:
[0010] Step 1: Weigh the raw materials according to the stoichiometric ratio. The raw materials include scandium-containing compounds, A-containing compounds, silicon-containing compounds, and chromium-containing compounds. Grind them to make them evenly mixed.
[0011] Step 2: Pre-calcine the raw materials from Step 1 at 600-1200℃ in air atmosphere, and grind them evenly again after cooling.
[0012] Step 3: Calcine the material obtained in Step 2 at 1200–1600℃ in a vacuum, air, nitrogen, inert gas, or reducing atmosphere, keep warm, and slowly cool to room temperature to obtain chromium-doped ultrawideband near-infrared fluorescent material.
[0013] Furthermore, in step one, the scandium-containing compound is scandium nitrate or scandium oxide, the A-containing compound is an A-containing nitrate or an A-containing oxide, the silicon-containing compound is silicon dioxide, and the chromium-containing compound is chromium nitrate or chromium oxide.
[0014] Furthermore, in step two, the pre-calcination time is 1 to 10 hours. Considering the optimization of the synthesis process for high-purity products and energy conservation, preferably, the pre-calcination temperature is 800 to 1000°C, and the pre-calcination time is 4 to 6 hours.
[0015] Furthermore, in step three, the calcination time is 1–10 hours. Preferably, the calcination temperature is 1300–1500℃, and the calcination time is 4–8 hours, resulting in higher product purity. Preferably, the calcination atmosphere is air or nitrogen, adjusting the ratio of +3 and +4 valent chromium ions in the product.
[0016] Preparation principle: Based on the mature solid-state reaction preparation process, a dual strategy of optimizing the doping concentration of activating ions (chromium ions) and cation solid solution substitution of the matrix material is adopted. By controlling the doping of A ions with different ionic radii and adjusting their doping concentration, the crystal field intensity of the phosphor matrix is changed, and the spectral performance of the fluorescent material is modulated, so as to realize the synthesis of ultra-wideband near-infrared phosphors, ultra-wideband near-infrared luminescence performance and spectral control.
[0017] Beneficial effects: Compared with the prior art, the present invention has the following significant features:
[0018] 1. The phosphor exhibits broadband emission under blue light excitation, and its emission spectrum can simultaneously cover the near-infrared light in the NIR-I and NIR-II regions. Furthermore, the peak position and full width at half maximum (FWHM) of the phosphor emission spectrum can be controlled by adjusting the chromium ion doping concentration.
[0019] 2. When the emission spectrum of the phosphor is in NIR-II, the substitution of Sc by A ions can be adjusted. 3+ The emission bandwidth of the phosphor is adjusted by the concentration of chromium ions and the concentration of chromium ions.
[0020] 3. The phosphor is prepared by solid-phase reaction, which is simple, highly reproducible, and yields stable product quality.
[0021] 4. It has broad application prospects in the field of near-infrared phosphor conversion light-emitting diodes and can be applied to fields such as non-destructive testing, biological imaging and machine vision. Attached Figure Description
[0022] Figure 1 These are the X-ray diffraction patterns of the phosphors obtained in Examples 1-7 of this invention;
[0023] Figure 2 This is the excitation and emission spectrum of the phosphor obtained in Example 1 of the present invention;
[0024] Figure 3 This is the excitation and emission spectrum of the phosphor obtained in Example 2 of the present invention;
[0025] Figure 4 This is the excitation and emission spectrum of the phosphor obtained in Example 3 of the present invention;
[0026] Figure 5 These are the emission spectra of the phosphors obtained in Examples 1 to 7 of this invention;
[0027] Figure 6 These are the X-ray diffraction patterns of the phosphors obtained in Examples 5, 8-15 of this invention;
[0028] Figure 7 These are the normalized emission spectra of the phosphors obtained in Examples 5, 8-15 of this invention;
[0029] Figure 8 These are the X-ray diffraction patterns of the phosphors obtained in Examples 16-23 of this invention;
[0030] Figure 9 These are the emission spectra of the phosphors obtained in Examples 12, 16, 17, 20 and 23 of this invention. Detailed Implementation
[0031] In the following embodiments, the XRD patterns of the samples were tested using a D2-PHASER X-ray diffractometer (Bruker GmbH, Germany), and the excitation and emission spectra of the phosphors were tested using a FLS1000 steady-state / transient fluorescence spectrometer (Edinburgh Instruments Ltd., UK).
[0032] Example 1
[0033] A method for preparing a chromium-doped ultrawideband near-infrared fluorescent material includes the following steps:
[0034] (1) High-purity powders of Sc2O3, SiO2, and Cr2O3 are used as raw materials, according to the general formula Sc 2-x A x Si2O7:yCr 3+ Calculate the stoichiometric ratio of (x=0,y=0.001) and weigh the raw materials. Place them in an agate mortar and grind for about 30 minutes to ensure that the raw materials are fully mixed.
[0035] (2) Then put the mixture into a corundum crucible and place it in a muffle furnace for pre-calcination at 900°C in air atmosphere for 4 hours.
[0036] (3) After thoroughly grinding the pre-calcined powder, it was transferred to a high-temperature atmosphere reactor and synthesized at 1400℃ for 5 hours in air atmosphere to obtain a chromium-doped ultrawideband near-infrared fluorescent material with the chemical formula Sc2Si2O7:0.001Cr. 3+ .
[0037] The phosphor obtained in this embodiment was analyzed, such as... Figure 1 The X-ray diffraction pattern shows that the phosphor obtained in Example 1 is a pure phase. Figure 2 The images show the emission spectrum obtained by excitation of the phosphor at a wavelength of 466 nm and the excitation spectrum obtained by monitoring at a wavelength of 930 nm, respectively. Figure 2 The excitation spectrum shows that the phosphor obtained in Example 1 exhibits obvious excitation peaks at 250–400 nm, 400–600 nm, and 600–800 nm, respectively, indicating that the phosphor in this example can be effectively excited by blue light. Figure 2 The emission spectrum in the sample shows a distinct emission peak at 930 nm, indicating that the phosphor in this embodiment can emit NIR-I near-infrared light.
[0038] Example 2
[0039] A method for preparing a chromium-doped ultrawideband near-infrared fluorescent material includes the following steps:
[0040] (1) High-purity powders of Sc2O3, SiO2, and Cr2O3 are used as raw materials, according to the general formula Sc 2-x A x Si2O7:yCr 3+ / 4+ Calculate the stoichiometric ratio of (x=0,y=0.005) and weigh the raw materials. Place them in an agate mortar and grind for about 30 minutes to ensure that the raw materials are fully mixed.
[0041] (2) Then put the mixture into a corundum crucible and place it in a muffle furnace for pre-calcination at 900°C in air atmosphere for 4 hours.
[0042] (3) After thoroughly grinding the pre-calcined powder, it was transferred to a high-temperature atmosphere reactor and synthesized at 1400℃ for 5 hours in air atmosphere to obtain a chromium-doped ultrawideband near-infrared fluorescent material with the chemical formula Sc2Si2O7:0.005Cr. 3+ / 4+ .
[0043] The phosphor obtained in this embodiment was analyzed, such as... Figure 1 The X-ray diffraction pattern shows that the phosphor obtained in Example 2 is a pure phase. Figure 3 The images show the emission spectrum obtained by excitation of the phosphor at a wavelength of 466 nm and the excitation spectrum obtained by monitoring at a wavelength of 1275 nm, respectively. Figure 3The excitation spectrum shows that the phosphor obtained in Example 2 exhibits obvious excitation peaks at 250–400 nm, 400–600 nm, and 600–800 nm, respectively. In particular, the excitation intensity is best in the 400–600 nm band, with a peak value of 466 nm, indicating that the phosphor of this example can be effectively excited by blue light. Figure 3 The emission spectrum of the phosphor shows obvious emission peaks at 930 nm and 1275 nm, and the emission peak at 930 nm is stronger than that at 1275 nm, indicating that the phosphor can emit both NIR-I and NIR-II near-infrared light as the concentration of chromium ions increases.
[0044] Example 3
[0045] A method for preparing a chromium-doped ultrawideband near-infrared fluorescent material includes the following steps:
[0046] (1) High-purity powders of Sc2O3, SiO2, and Cr2O3 are used as raw materials, according to the general formula Sc 2-x A x Si2O7:yCr 3+ / 4+ Calculate the stoichiometric ratio of (x=0,y=0.01) and weigh the raw materials. Place them in an agate mortar and grind for about 30 minutes to ensure that the raw materials are fully mixed.
[0047] (2) Then put the mixture into a corundum crucible and place it in a muffle furnace for pre-calcination at 900°C in air atmosphere for 4 hours.
[0048] (3) After thoroughly grinding the pre-calcined powder, it was transferred to a high-temperature atmosphere reactor and synthesized at 1400℃ for 5 hours in air atmosphere to obtain a chromium-doped ultrawideband near-infrared fluorescent material with the chemical formula Sc2Si2O7:0.01Cr. 3+ / 4+ .
[0049] The phosphor obtained in this embodiment was analyzed, such as... Figure 1 The X-ray diffraction pattern shows that the phosphor obtained in Example 3 is a pure phase. Figure 4 The images show the emission spectrum obtained by excitation of the phosphor at a wavelength of 466 nm and the excitation spectrum obtained by monitoring at a wavelength of 1275 nm, respectively. Figure 4 The excitation spectrum shows that the phosphor obtained in Example 3 exhibits obvious excitation peaks at 250–400 nm, 400–600 nm, and 600–800 nm, respectively. In particular, the excitation intensity is best in the 400–600 nm band, with a peak value of 466 nm, indicating that the phosphor of this example can be effectively excited by blue light. Figure 4The emission spectrum of the phosphor shows obvious emission peaks at 930 nm and 1275 nm, and the emission peak at 1275 nm is stronger than that at 930 nm, indicating that as the concentration of chromium ions increases, the range of emitted infrared light changes from the NIR-I region to the NIR-II region.
[0050] Example 4
[0051] The remaining steps in this embodiment are the same as in Embodiment 1, except that the general formula of the chromium-doped ultrawideband near-infrared fluorescent material is Sc2Si2O7:0.03Cr. 4+ (x = 0, y = 0.03).
[0052] Example 5
[0053] The remaining steps in this embodiment are the same as in Embodiment 1, except that the general formula of the chromium-doped ultrawideband near-infrared fluorescent material is Sc2Si2O7:0.07Cr. 4+ (x = 0, y = 0.07).
[0054] Example 6
[0055] The remaining steps in this embodiment are the same as in Embodiment 1, except that the general formula of the chromium-doped ultrawideband near-infrared fluorescent material is Sc2Si2O7:0.1Cr. 4+ (x = 0, y = 0.1).
[0056] Example 7
[0057] The remaining steps in this embodiment are the same as in Embodiment 1, except that the general formula of the chromium-doped ultrawideband near-infrared fluorescent material is Sc2Si2O7:0.15Cr. 4+ (x = 0, y = 0.15).
[0058] like Figure 1 The phosphors obtained in Examples 4-7 were pure phases. Figure 5 The emission spectra of the phosphors obtained in Examples 1-7 showed a clear emission peak at 1275 nm, and the emission peak at 930 nm almost disappeared, indicating that the phosphor emission was influenced by Cr. 3+ As the doping concentration increases, the emitted infrared light range shifts from the NIR-I region to the NIR-II region. When the concentration reaches 0.03, the phosphor emits NIR-II near-infrared light.
[0059] Table 1 summarizes the relevant performance parameters of the near-infrared phosphors from Examples 1 to 7. It can be seen that the phosphors exhibit broadband emission under blue light excitation, and their emission spectra simultaneously cover the near-infrared regions of NIR-I and NIR-II. Furthermore, the peak position, intensity, and full width at half maximum (FWHM) of the emission peaks in the spectrum can be adjusted by regulating the chromium ion doping concentration. Specifically, when the chromium ion doping concentration is low (y = 0.001), the emission peak near 930 nm (with the luminescence center being Cr) is... 3+ The intensity of ) is the highest, while the emission peak near 1260 nm (the luminescent center is Cr) is the highest. 4+ The emission is very weak, exhibiting a single-peak pattern with a small full width at half maximum (FWHM) of 209 nm. When the chromium ion doping concentration (y) is between 0.005 and 0.15, Cr... 3+ The emission peak of Cr gradually decreases and undergoes a redshift, while Cr 4+ The emission peak gradually rises and undergoes a blue shift, and the entire emission spectrum gradually changes from a bimodal shape to a single peak shape at around 1260 nm; due to Cr 3+ / Cr 4+ Changes in ion luminescence intensity and Cr 4+ The emission peak broadens with increasing concentration, and the full width at half maximum (FWHM) of the overall emission spectrum shows a trend of first increasing, then decreasing, and then increasing again.
[0060] Table 1. Sc2Si2O7:yCr obtained in Examples 1-7 M+ Relevant performance parameters of near-infrared phosphor
[0061]
[0062] Of Examples 1-7, Example 5 exhibits the highest luminous intensity. However, the luminous intensity gradually decreases after y exceeds 0.07 due to the concentration quenching effect. Therefore, considering both luminous intensity and full width at half maximum (FWHM) of Examples 1-7, Example 5 is the optimal example.
[0063] Example 8
[0064] The remaining steps in this embodiment are the same as in Embodiment 5, the only difference being that: the general formula for chromium-doped ultrawideband near-infrared fluorescent materials is Sc. 1.97 Y 0.03 Si2O7:0.07Cr 4+ (x = 0.03, y = 0.07), the raw materials are Sc2O3, Y2O3, SiO2 and Cr2O3.
[0065] Example 9
[0066] The remaining steps in this embodiment are the same as in Embodiment 5, the only difference being that: the general formula for chromium-doped ultrawideband near-infrared fluorescent materials is Sc. 1.93 Y 0.07 Si2O7:0.07Cr4+ (x = 0.07, y = 0.07).
[0067] Example 10
[0068] The remaining steps in this embodiment are the same as in Embodiment 5, the only difference being that: the general formula for chromium-doped ultrawideband near-infrared fluorescent materials is Sc. 1.9 Y 0.1 Si2O7:0.07Cr 4+ (x = 0.1, y = 0.07).
[0069] Example 11
[0070] The remaining steps in this embodiment are the same as in Embodiment 5, the only difference being that: the general formula for chromium-doped ultrawideband near-infrared fluorescent materials is Sc. 1.87 Y 0.13 Si2O7:0.07Cr 4+ (x = 0.13, y = 0.07).
[0071] Example 12
[0072] The remaining steps in this embodiment are the same as in Embodiment 5, the only difference being that: the general formula for chromium-doped ultrawideband near-infrared fluorescent materials is Sc. 1.83 Y 0.17 Si2O7:0.07Cr 4+ (x = 0.17, y = 0.07).
[0073] Example 13
[0074] The remaining steps in this embodiment are the same as in Embodiment 5, the only difference being that: the general formula for chromium-doped ultrawideband near-infrared fluorescent materials is Sc. 1.8 Y 0.2 Si2O7:0.07Cr 4+ (x = 0.2, y = 0.07).
[0075] Example 14
[0076] The remaining steps in this embodiment are the same as in Embodiment 5, the only difference being that: the general formula for chromium-doped ultrawideband near-infrared fluorescent materials is Sc. 1.77 Y 0.23 Si2O7:0.07Cr 4+ (x = 0.23, y = 0.07).
[0077] Example 15
[0078] The remaining steps in this embodiment are the same as in Embodiment 5, the only difference being that: the general formula for chromium-doped ultrawideband near-infrared fluorescent materials is Sc. 1.7 Y 0.3Si2O7:0.07Cr 4+ (x = 0.3, y = 0.07).
[0079] Table 2. Sc as described in Examples 5, 8-15 2-x Y x Si2O7:0.07Cr 4+ Relevant performance parameters of near-infrared phosphor
[0080] <![CDATA[Y 3+ Doping concentration x value Emission peak (nm) Full width at half maximum (nm) Example 5 0 1272 348 Example 8 0.03 1269 352 Example 9 0.07 1258 389 Example 10 0.1 1248 394 Example 11 0.13 1248 386 Example 12 0.17 1225 440 Example 13 0.2 1222 434 Example 14 0.23 1191 439 Example 15 0.3 1180 434
[0081] like Figure 6 The X-ray diffraction pattern shows that the prepared near-infrared phosphor is a pure phase, and Y... 3+ When the doping concentration x is between 0 and 0.3, it has no effect on the phase structure. For example... Figure 7 The normalized emission spectrum shows that the NIR-II emission bandwidth of this phosphor can change with increasing x value. 3+ The doping concentration x and the corresponding full width at half maximum (FWHM) y can be approximated as linearly increasing. By linearly fitting the x value and the corresponding FWHM y, the following formula can be obtained: y = 355.352 + 339.703 * x. When x is 0.17, the maximum FWHM is 440 nm. The relevant performance parameters are shown in Table 2 above.
[0082] Example 16
[0083] The remaining steps in this embodiment are the same as in Embodiment 9, the only difference being that: the general formula for chromium-doped ultrawideband near-infrared fluorescent materials is Sc. 1.93 Eu 0.07 Si2O7:0.07Cr 4+ (x = 0.07, y = 0.07), the raw materials are Sc2O3, Eu2O3, SiO2 and Cr2O3.
[0084] Example 17
[0085] The remaining steps in this embodiment are the same as in Embodiment 9, the only difference being that: the general formula for chromium-doped ultrawideband near-infrared fluorescent materials is Sc. 1.93 Gd 0.07 Si2O7:0.07Cr 4+ (x = 0.07, y = 0.07), the raw materials are Sc2O3, Gd2O3, SiO2 and Cr2O3.
[0086] Example 18
[0087] The remaining steps in this embodiment are the same as in Embodiment 9, the only difference being that: the general formula for chromium-doped ultrawideband near-infrared fluorescent materials is Sc. 1.93 Tb 0.07 Si2O7:0.07Cr 4+(x = 0.07, y = 0.07), the raw materials are Sc2O3, Tb4O7, SiO2 and Cr2O3.
[0088] Example 19
[0089] The remaining steps in this embodiment are the same as in Embodiment 9, the only difference being that: the general formula for chromium-doped ultrawideband near-infrared fluorescent materials is Sc. 1.93 Dy 0.07 Si2O7:0.07Cr 4+ (x = 0.07, y = 0.07), the raw materials are Sc2O3, Dy2O3, SiO2 and Cr2O3.
[0090] Example 20
[0091] The remaining steps in this embodiment are the same as in Embodiment 9, the only difference being that: the general formula for chromium-doped ultrawideband near-infrared fluorescent materials is Sc. 1.93 Ho 0.07 Si2O7:0.07Cr 4+ (x = 0.07, y = 0.07), the raw materials are Sc2O3, Ho2O3, SiO2 and Cr2O3.
[0092] Example 21
[0093] The remaining steps in this embodiment are the same as in Embodiment 9, the only difference being that: the general formula for chromium-doped ultrawideband near-infrared fluorescent materials is Sc. 1.93 Er 0.07 Si2O7:0.07Cr 4+ (x = 0.07, y = 0.07), the raw materials are Sc2O3, Er2O3, SiO2 and Cr2O3.
[0094] Example 22
[0095] The remaining steps in this embodiment are the same as in Embodiment 9, the only difference being that: the general formula for chromium-doped ultrawideband near-infrared fluorescent materials is Sc. 1.93 Tm 0.07 Si2O7:0.07Cr 4+ (x = 0.07, y = 0.07), the raw materials are Sc2O3, Tm2O3, SiO2 and Cr2O3.
[0096] Example 23
[0097] The remaining steps in this embodiment are the same as in Embodiment 9, the only difference being that: the general formula for chromium-doped ultrawideband near-infrared fluorescent materials is Sc. 1.93 Yb 0.07 Si2O7:0.07Cr 4+(x=0.07,y=0.07)), the raw materials are Sc2O3, Yb2O3, SiO2 and Cr2O3.
[0098] like Figure 8 The near-infrared phosphors prepared in Examples 16-23 are all pure phases, and the phase structure of the obtained phosphors is not affected when A is Eu, Gd, Tb, Dy, Ho, Er, Tm, or Yb. Figure 9 The emission spectra show that when A is Eu or Gd, the full width at half maximum (FWHM) of the emission spectrum of the prepared phosphor is altered to some extent. When A is Ho or Yb, the shape of the emission spectrum of the prepared phosphor is partially changed, but all are broadband emission. Therefore, when A is one or more of the elements Y, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb, the prepared materials are all near-infrared fluorescent materials with broadband emission.
[0099] Example 24
[0100] The remaining steps in this embodiment are the same as in Embodiment 17, the only difference being that the general formula for chromium-doped ultrawideband near-infrared fluorescent materials is Sc. 1.7 Gd 0.3 Si2O7:0.07Cr 4+ (x = 0.3, y = 0.07).
[0101] The emission spectrum of the sample obtained in this embodiment ranges from 825 to 1620 nm, with a peak value of 1100 nm and a full width at half maximum (FWHM) of 480 nm.
[0102] Example 25
[0103] The remaining steps in this embodiment are the same as in Embodiment 24, the only difference being that the general formula for chromium-doped ultrawideband near-infrared fluorescent materials is Sc. 1.7 Sm 0.3 Si2O7:0.07Cr 4+ (x = 0.3, y = 0.07), the raw materials are Sc2O3, Sm2O3, SiO2 and Cr2O3.
[0104] The emission spectrum of the sample obtained in this embodiment ranges from 850 to 1620 nm, with a peak value of 1132 nm and a full width at half maximum (FWHM) of 440 nm.
[0105] Example 26
[0106] The remaining steps in this embodiment are the same as in Embodiment 24, the only difference being that the general formula for chromium-doped ultrawideband near-infrared fluorescent materials is Sc. 1.7 Lu 0.3 Si2O7:0.07Cr 4+(x = 0.3, y = 0.07), the raw materials are Sc2O3, Tm2O3, SiO2 and Cr2O3.
[0107] The emission spectrum of the sample obtained in this embodiment ranges from 860 to 1620 nm, with a peak value of 1124 nm and a full width at half maximum (FWHM) of 423 nm.
[0108] Example 27
[0109] A method for preparing a chromium-doped ultrawideband near-infrared fluorescent material includes the following steps:
[0110] (1) High-purity powders of Sc2O3, Y2O3, SiO2, and Cr2O3 are used as raw materials, according to the general formula Sc 1.5 Y 0.5 Si2O7:0.3Cr 4+ Calculate the stoichiometric ratio and weigh the raw materials, then grind them in an agate mortar for about 30 minutes to ensure they are fully mixed.
[0111] (2) Then put the mixture into a corundum crucible and place it in a muffle furnace for pre-calcination at 600°C in air atmosphere for 1 hour.
[0112] (3) After thoroughly grinding the pre-calcined powder, it was transferred to a high-temperature atmosphere reactor and synthesized at 1200℃ for 1 hour under a reducing atmosphere of 5% H2 / 95% Ar to prepare a chromium-doped ultrawideband near-infrared fluorescent material with the chemical formula Sc. 1.5 Y 0.5 Si2O7:0.3Cr 4+ .
[0113] The emission spectrum of the sample obtained in this embodiment ranges from 840 to 1620 nm, with a peak value of 1260 nm and a full width at half maximum (FWHM) of 445 nm.
[0114] Example 28
[0115] A method for preparing a chromium-doped ultrawideband near-infrared fluorescent material includes the following steps:
[0116] (1) High-purity powders of Sc2O3, Y2O3, SiO2, and Cr2O3 are used as raw materials, according to the general formula Sc 1.5 Y 0.5 Si2O7:0.3Cr 4+ Calculate the stoichiometric ratio and weigh the raw materials, then grind them in an agate mortar for about 30 minutes to ensure they are fully mixed.
[0117] (2) Then put the mixture into a corundum crucible and place it in a muffle furnace for pre-calcination at 1200°C in air atmosphere for 10 hours.
[0118] (3) After thoroughly grinding the pre-calcined powder, it was transferred to a high-temperature atmosphere reactor and synthesized at 1600℃ for 1 hour under a nitrogen atmosphere to prepare a chromium-doped ultrawideband near-infrared fluorescent material with the chemical formula Sc. 1.5 Y 0.5 Si2O7:0.3Cr 4+ .
[0119] The emission spectrum of the sample obtained in this embodiment ranges from 840 to 1620 nm, with a peak value of 1262 nm and a full width at half maximum (FWHM) of 448 nm.
[0120] Example 29
[0121] A method for preparing a chromium-doped ultrawideband near-infrared fluorescent material includes the following steps:
[0122] (1) High-purity powders of Sc(NO3)3, Y(NO3)3, SiO2 and Cr(NO3)3 are used as raw materials, according to the general formula Sc 1.5 Y 0.5 Si2O7:0.3Cr 4+ Calculate the stoichiometric ratio and weigh the raw materials, then grind them in an agate mortar for about 30 minutes to ensure they are fully mixed.
[0123] (2) Then put the mixture into a corundum crucible and place it in a muffle furnace for pre-calcination at 800°C in air atmosphere for 6 hours.
[0124] (3) After thoroughly grinding the pre-calcined powder, it was transferred to a high-temperature atmosphere reactor and synthesized at 1300℃ for 4 hours under an argon atmosphere to obtain a chromium-doped ultrawideband near-infrared fluorescent material with the chemical formula Sc. 1.5 Y 0.5 Si2O7:0.3Cr 4+ .
[0125] The emission spectrum of the sample obtained in this embodiment ranges from 840 to 1620 nm, with a peak value of 1258 nm and a full width at half maximum (FWHM) of 450 nm.
[0126] Example 30
[0127] A method for preparing a chromium-doped ultrawideband near-infrared fluorescent material includes the following steps:
[0128] (1) High-purity powders of Sc(NO3)3, Ga2O3, SiO2, and Cr(NO3)3 were used as raw materials, according to the general formula Sc 1.5 Ga 0.5 Si2O7:0.3Cr 4+ Calculate the stoichiometric ratio and weigh the raw materials, then grind them in an agate mortar for about 30 minutes to ensure they are fully mixed.
[0129] (2) Then put the mixture into a corundum crucible and place it in a muffle furnace for pre-calcination at 1000°C in air atmosphere for 5 hours.
[0130] (3) After thoroughly grinding the pre-calcined powder, it was transferred to a high-temperature vacuum furnace and synthesized at 1500℃ for 8 hours under vacuum conditions to obtain a chromium-doped ultrawideband near-infrared fluorescent material with the chemical formula Sc. 1.5 Ga 0.5 Si2O7:0.3Cr 4+ .
[0131] The emission spectrum of the sample obtained in this embodiment ranges from 870 to 1620 nm, with a peak value of 1255 nm and a full width at half maximum (FWHM) of 432 nm.
[0132] Among the above embodiments, Embodiment 3 has a full width at half maximum (FWHM) of 562 nm, making it the optimal embodiment with the largest FWHM. Considering the luminous intensity, Embodiments 15 and 17 are the optimal embodiments.
Claims
1. A method for preparing a chromium-doped ultrawideband near-infrared fluorescent material, characterized in that, Includes the following steps: Step 1: Weigh the raw materials according to the stoichiometric ratio. The raw materials include scandium-containing compounds, A-containing compounds, silicon-containing compounds, and chromium-containing compounds. Grind them to make them evenly mixed. Step 2: Pre-calcine the raw materials from Step 1 at 600~1200℃ in air atmosphere, and grind them evenly again after cooling. Step 3: Calcine the product obtained in Step 2 at 1200~1600℃ in a vacuum, air, nitrogen, inert gas or reducing atmosphere, and slowly cool it to room temperature to obtain chromium-doped ultrawideband near-infrared fluorescent material. The general chemical formula of the chromium-doped ultrawideband near-infrared fluorescent material is: Sc 2-x A x Si2O7:yCr M Where A is one or more of the elements Y, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Ga, 0.03≤x≤0.5, 0.001≤y≤0.3, and M is one or more of 3+ and 4+.
2. The method for preparing a chromium-doped ultrawideband near-infrared fluorescent material according to claim 1, characterized in that: The value of x is in the range of 0.03 ≤ x ≤ 0.3, and the value of y is in the range of 0.005 ≤ y ≤ 0.
3.
3. The method for preparing a chromium-doped ultrawideband near-infrared fluorescent material according to claim 1, characterized in that: The emission spectrum of the near-infrared fluorescent material has a full width at half maximum (FWHM) greater than 330 nm.
4. The method for preparing a chromium-doped ultrawideband near-infrared fluorescent material according to claim 1, characterized in that: In step one, the scandium-containing compound is scandium nitrate or scandium oxide, the A-containing compound is A-containing nitrate or A-containing oxide, the silicon-containing compound is silicon dioxide, and the chromium-containing compound is chromium nitrate or chromium oxide.
5. The method for preparing a chromium-doped ultrawideband near-infrared fluorescent material according to claim 1, characterized in that: In step two, the pre-calcination time is 1 to 10 hours.
6. The method for preparing a chromium-doped ultrawideband near-infrared fluorescent material according to claim 1, characterized in that: In step two, the pre-calcination temperature is 800~1000℃ and the pre-calcination time is 4~6 hours.
7. The method for preparing a chromium-doped ultrawideband near-infrared fluorescent material according to claim 1, characterized in that: In step three, the calcination time is 1 to 10 hours.
8. The method for preparing a chromium-doped ultrawideband near-infrared fluorescent material according to claim 1, characterized in that: In step three, the calcination temperature is 1300~1500℃ and the calcination time is 4~8 hours.
9. The method for preparing a chromium-doped ultrawideband near-infrared fluorescent material according to claim 1, characterized in that: In step three, the calcination atmosphere is air or nitrogen.