Light emitting material with blue light excitation broadband near-infrared emission and preparation method thereof

Abstract

This invention relates to the field of luminescent materials technology, and particularly to a luminescent material that emits broadband near-infrared light upon blue light excitation and its preparation method. The chemical formula of the above-mentioned luminescent material is: Li 1‑x Al 1‑ y SiO4: x%Ni, y%Cr, where x and y are the molar percentages of Ni and Cr, respectively. The preparation method includes weighing the raw materials, mixing them evenly, calcining them, naturally cooling to room temperature, and then grinding to obtain the aforementioned luminescent material. The luminescent material obtained by this invention uses LiAlSiO4 as a matrix, giving it excellent chemical and thermal stability; Cr / Ni doping can achieve 400nm photoexcitation, with the emission position located in the near-infrared II region; the obtained luminescent material is easily combined with blue LEDs to fabricate devices that emit broadband near-infrared light with blue light excitation, possessing potential applications in biology, chemistry, medicine, and other fields.

Description

Technical Field

[0001] This invention relates to the field of luminescent materials technology, and in particular to a luminescent material that emits broadband near-infrared light excited by blue light and its preparation method. Background Technology

[0002] In synthetic chemistry and related industries, the accurate determination of trace amounts of secondary components in solvents is crucial. While traditional methods such as chromatography can measure these trace components relatively accurately, they lack in-situ, non-invasive, and real-time monitoring capabilities. In recent years, near-infrared spectroscopy has proven to provide non-destructive and immediate detection results, leading to significant interest in this technology. Near-infrared light sources are the core components of near-infrared spectroscopy testing equipment. Among all near-infrared light sources, miniature near-infrared PC LEDs excited by LED chips are considered one of the best choices for future near-infrared light sources.

[0003] Near-infrared PC LEDs typically generate blue light using a blue LED chip, which then excites near-infrared phosphors to produce the desired near-infrared emission. Therefore, the performance of the near-infrared phosphor material is crucial in determining the performance of near-infrared PC LEDs, including emission peak value, full width at half maximum (FWHM), and luminous intensity. Since blue LED chip technology is already mature, current research primarily focuses on the development of high-performance near-infrared phosphors.

[0004] Near-infrared spectroscopy is generally divided into near-infrared I (700–1000 nm) and near-infrared II (1000–1700 nm). In the near-infrared I region, current methods primarily utilize Cr... 3+ Eu 2+ Mn 2+ and Fe 3+ Realization of doped luminescent systems, such as phosphors LiScP2O7:Cr 3 + The emission is located at 880 nm, with a full width at half maximum (FWHM) of 170 nm (Chem. Mater. 2020, 32, 2430). Correspondingly, researchers also found that Ni... 2+ Cr 4+ Low-valence Bi ions can achieve near-infrared II emission; however, experiments have shown that phosphors doped with these ions exhibiting near-infrared II emission have relatively low luminescence efficiency. Meanwhile, Ni... 2+ The fact that the ion excitation site is located in the ultraviolet region is also one of the reasons for its low efficiency.

[0005] In recent years, researchers have attempted to address the aforementioned issues by using methods such as Cr / Ni co-doping to solve the problems of excitation sites located in the ultraviolet region and low quantum efficiency. For example, in the Mg2SnO4:Cr / Ni fluorescent system, a broad-spectrum near-infrared emission was generated under 455nm light excitation, which can be applied to the detection of various organic materials (Adv. Mater. Technol. 2022, 2201181). Currently, there are relatively few systems that achieve efficient near-infrared emission through Cr / Ni co-doping, and the performance of the materials and the corresponding processes still need to be optimized. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies and propose a luminescent material that emits broadband near-infrared light with blue light excitation and its preparation method. Using LiAlSiO4 as a matrix, the luminescent material has excellent chemical and thermal stability, and 400nm photoexcitation is achieved through Cr / Ni doping.

[0007] To achieve the above objectives, the present invention adopts the following specific technical solution:

[0008] The luminescent material for blue light-excited broadband near-infrared emission provided by this invention has the chemical formula: Li 1-x Al 1-y SiO4: x%Ni, y%Cr, where x and y are the molar percentages of Ni and Cr, respectively, and their values ​​range from 0 < x ≤ 1 to 0 < y ≤ 7.

[0009] Preferably, the values ​​of x and y are x = 0.1 and y = 0.5, respectively.

[0010] The method for preparing a blue light-excited broadband near-infrared luminescent material provided by the present invention includes the following steps:

[0011] S1. Weigh out Li-containing compounds, Al-containing compounds, Si-containing compounds, Ni-containing compounds, and Cr-containing compounds as raw materials according to the stoichiometric ratio of their chemical formulas;

[0012] S2. After the raw materials are mixed evenly, they are calcined, naturally cooled to room temperature, and then ground to obtain a luminescent material that emits broadband near-infrared light excited by blue light.

[0013] Preferably, the Li-containing compounds, Al-containing compounds, Si-containing compounds, Ni-containing compounds, and Cr-containing compounds are selected from oxides, carbonates, oxalates, acetates, or hydroxides.

[0014] Preferably, Li2CO3, Al2O3, SiO2, NiO and Cr2O3 are selected as raw materials.

[0015] Preferably, the raw materials are mixed evenly using mechanical ball milling or sol-gel method, with alcohol used as the solvent in mechanical ball milling.

[0016] Preferably, after the raw materials are mixed evenly, they are pre-fired and then calcined. The pre-fired temperature is 300℃~600℃, more preferably 500℃; the pre-fired time is 2h~30h, more preferably 6h.

[0017] Preferably, the containers used for pre-firing and calcining are ceramic boats or corundum boats.

[0018] Preferably, the calcination temperature is 800℃~1300℃, more preferably 1200℃; the calcination time is 2h~10h, more preferably 6h; and the calcination atmosphere is air or pure oxygen.

[0019] The present invention can achieve the following technical effects:

[0020] The luminescent material provided by this invention uses LiAlSiO4 as a matrix, which gives the luminescent material excellent chemical and thermal stability. Cr / Ni doping enables 400nm photoexcitation, with the luminescent position located in the near-infrared II region. The prepared luminescent material is easily combined with blue LEDs to fabricate devices that emit broadband near-infrared light with blue light excitation, possessing potential applications in biology, chemistry, medicine, and other fields. Attached Figure Description

[0021] Figure 1 The X-ray diffraction patterns are those of the blue light-excited broadband near-infrared luminescent materials prepared according to Examples 1-8 of the present invention.

[0022] Figure 2 The X-ray diffraction patterns are those of blue light-excited broadband near-infrared luminescent materials prepared according to Examples 3, 9 to 11 of the present invention.

[0023] Figure 3 This is a SEM image of a blue light-excited broadband near-infrared luminescent material prepared according to Example 3 of the present invention.

[0024] Figure 4 This is the excitation and emission spectrum of the blue light-excited broadband near-infrared luminescent material prepared according to Example 3 of the present invention.

[0025] Figure 5 The images show the emission spectra of the blue light-excited broadband near-infrared luminescent materials prepared according to Examples 1-8 of the present invention.

[0026] Figure 6 This is the emission spectrum of the blue light-excited broadband near-infrared luminescent material prepared according to Examples 3, 9 to 11 of the present invention. Detailed Implementation

[0027] In the following description, embodiments of the invention will be described with reference to the accompanying drawings. In the description below, the same modules are denoted by the same reference numerals. Where the same reference numerals are used, their names and functions are also the same. Therefore, their detailed description will not be repeated.

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not constitute a limitation thereof.

[0029] This invention provides a luminescent material that emits broadband near-infrared light upon blue light excitation. The chemical formula of this luminescent material is: Li 1-x Al 1-y SiO4: x%Ni, y%Cr, where x and y are the molar percentages of Ni and Cr, respectively, and their values ​​range from 0 < x ≤ 1 to 0 < y ≤ 7. Preferably, x = 0.1 and y = 0.5.

[0030] This invention also provides a method for preparing a blue light-excited broadband near-infrared luminescent material, comprising the following steps:

[0031] S1. Weigh out Li-containing compounds, Al-containing compounds, Si-containing compounds, Ni-containing compounds, and Cr-containing compounds as raw materials according to their chemical formula stoichiometry.

[0032] Among them, Li-containing compounds, Al-containing compounds, Si-containing compounds, Ni-containing compounds, and Cr-containing compounds can be selected from oxides, carbonates, oxalates, acetates, or hydroxides containing the corresponding elements.

[0033] Specifically, Li2CO3, Al2O3, SiO2, NiO, and Cr2O3 are selected as raw materials.

[0034] S2. After the raw materials are mixed evenly, they are calcined, naturally cooled to room temperature, and then ground to obtain a luminescent material that emits broadband near-infrared light excited by blue light.

[0035] When mixing thoroughly, mechanical ball milling or sol-gel method is used, with alcohol as the solvent in mechanical ball milling.

[0036] Preferably, the raw materials are mixed evenly and then pre-fired before calcination. The pre-fired temperature is 300℃~600℃, preferably 500℃; the pre-fired time is 2h~30h, preferably 6h; and the containers used for pre-fired and calcined are ceramic boats or corundum boats.

[0037] The calcination temperature is 800℃~1300℃, preferably 1200℃; the calcination time is 2h~10h, preferably 6h; the calcination atmosphere is air or pure oxygen.

[0038] The luminescent material and preparation method provided by the present invention will be described below with reference to specific embodiments.

[0039] Example 1

[0040] According to Li 1-x Al 1-y The molar ratio of SiO4:0.1% Ni, 0.1% Cr was determined by weighing Li2CO3, Al2O3, SiO2, NiO, and Cr2O3. The mixture was ground 2-3 times with anhydrous ethanol until homogeneous. The ground sample was then dried in an oven at 80℃ for two hours. The powder was then placed in a corundum boat, and the boat containing the powder was placed in a high-temperature furnace and held at 400℃ in air for 6 hours, followed by natural cooling to room temperature. The sample was removed from the furnace, ground 2-3 times with alcohol, and then dried. The dried sample was placed in a corundum boat and placed in a high-temperature furnace. The furnace was slowly heated to 1350℃ in air and held for 6 hours, followed by natural cooling to room temperature before grinding to obtain Li. 1-x Al 1-y A luminescent material with blue light excitation and broadband near-infrared emission, consisting of SiO4: 0.1% Ni and 0.1% Cr.

[0041] Example 2

[0042] According to Li 1-x Al 1-y The molar ratio of SiO4:0.1% Ni, 0.3% Cr was used to weigh out Li2CO3, Al2O3, SiO2, NiO, and Cr2O3. The mixture was ground 2-3 times with anhydrous ethanol until homogeneous. The ground sample was dried in an oven at 80℃ for two hours. The powder was then placed in a corundum boat, and the boat containing the powder was placed in a high-temperature furnace and kept at 400℃ in air for 6 hours, followed by natural cooling to room temperature. The sample was removed from the furnace, ground 2-3 times with alcohol, and then dried. The dried sample was placed in a corundum boat and placed in a high-temperature furnace. The furnace was slowly heated to 1350℃ in air and held for 6 hours, followed by natural cooling to room temperature before grinding to obtain Li. 1-x Al 1-y A luminescent material with blue light excitation and broadband near-infrared emission, consisting of SiO4: 0.1% Ni and 0.3% Cr.

[0043] Example 3

[0044] According to Li 1-x Al 1-yThe molar ratio of SiO4:0.1% Ni, 0.5% Cr was used to weigh out Li2CO3, Al2O3, SiO2, NiO, and Cr2O3. The mixture was ground 2-3 times with anhydrous ethanol until homogeneous. The ground sample was dried in an oven at 80℃ for two hours. The powder was then placed in a corundum boat, and the boat containing the powder was placed in a high-temperature furnace and kept at 400℃ in air for 6 hours, followed by natural cooling to room temperature. The sample was removed from the furnace, ground 2-3 times with alcohol, and then dried. The dried sample was placed in a corundum boat and placed in a high-temperature furnace. The furnace was slowly heated to 1350℃ in air and kept at that temperature for 6 hours, followed by natural cooling to room temperature and grinding to obtain Li. 1-x Al 1-y SiO4: a luminescent material with blue light excitation and broadband near-infrared emission, consisting of 0.1% Ni and 0.5% Cr.

[0045] Examples 4-11

[0046] The preparation process is the same as in Examples 1-3, and the formulation of the luminescent materials in each example is shown in Table 1.

[0047] Table 1

[0048]

[0049] Figure 1 The X-ray diffraction patterns of the blue light-excited broadband near-infrared luminescent materials prepared in Examples 1-8 are shown. Figure 2 The X-ray diffraction patterns of the blue light-excited broadband near-infrared luminescent materials prepared in Examples 3, 9-11 are shown. Figure 1 and Figure 2 It can be seen that the X-ray diffraction pattern of the luminescent material prepared in the embodiments of the present invention is consistent with the standard diffraction pattern of LiAlSiO4, and the crystal structure did not change during the process of changing the raw material ratio. Figure 3 and Figure 4 The SEM images and excitation-emission spectra of the blue light-excited broadband near-infrared luminescent material prepared in Example 3 are shown respectively. It can be seen that the prepared luminescent material can be excited by 400nm light, and the luminescence position is located in the near-infrared II region. Figure 5 The emission spectra of the blue light-excited broadband near-infrared luminescent materials prepared in Examples 1-8 are shown. Figure 6 The emission spectra of the blue-light-excited broadband near-infrared luminescent materials prepared in Examples 3, 9-11 are shown. Figure 5 and Figure 6 A preferred embodiment of the luminescent material of the present invention can be obtained with x = 0.1 and y = 0.5, i.e., Li 1-x Al 1-y SiO4: 0.1% Ni, 0.5% Cr.

[0050] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0051] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

[0052] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A luminescent material that emits broadband near-infrared light upon blue light excitation, characterized in that, The chemical formula of the luminescent material is: Li 1-x Al 1-y SiO4: x%Ni, y%Cr, where x and y are the molar percentages of Ni and Cr, respectively, and their values ​​range from 0 to 1 and 0.5 to 7. The blue light-excited broadband near-infrared luminescent material can be excited by 400nm light, and the luminescent position is located in the near-infrared II region within the range of 1000 to 1700nm. The luminescent material that emits broadband near-infrared light excited by blue light is obtained by calcination at a temperature of 800℃ to 1200℃; a pre-calcination is performed before calcination at a temperature of 400℃.

2. The luminescent material for blue light-excited broadband near-infrared emission according to claim 1, characterized in that, The values ​​of x and y are x=0.1 and y=0.5, respectively.

3. A method for preparing a luminescent material that emits broadband near-infrared light excited by blue light as described in claim 1 or 2, characterized in that, Includes the following steps: S1. Weigh out Li-containing compounds, Al-containing compounds, Si-containing compounds, Ni-containing compounds, and Cr-containing compounds as raw materials according to the stoichiometric ratio of their chemical formulas; S2. After the raw materials are mixed evenly, they are calcined, naturally cooled to room temperature, and then ground to obtain a luminescent material that emits broadband near-infrared light excited by blue light.

4. The method for preparing a blue-light-excited broadband near-infrared luminescent material according to claim 3, characterized in that, The Li-containing compounds, Al-containing compounds, Si-containing compounds, Ni-containing compounds, and Cr-containing compounds are selected from oxides, carbonates, oxalates, acetates, or hydroxides.

5. The method for preparing a blue-light-excited broadband near-infrared luminescent material according to claim 3, characterized in that, Li2CO3, Al2O3, SiO2, NiO and Cr2O3 were selected as raw materials.

6. The method for preparing a blue-light-excited broadband near-infrared luminescent material according to claim 3, characterized in that, The raw materials are mixed evenly using mechanical ball milling or sol-gel method, with alcohol used as the solvent in the mechanical ball milling process.

7. The method for preparing a blue-light-excited broadband near-infrared luminescent material according to claim 3, characterized in that, After the raw materials are mixed evenly, they are first pre-fired and then calcined. The pre-fired time is 2h to 30h.

8. The method for preparing a luminescent material with blue light-excited broadband near-infrared emission according to claim 7, characterized in that, The containers used for pre-firing and calcination are ceramic boats or corundum boats.

9. The method for preparing a blue-light-excited broadband near-infrared luminescent material according to claim 3, characterized in that, The calcination time is 2h to 10h; the calcination atmosphere is air or pure oxygen.

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