A near-infrared luminescent material responding to light and force stimulation, and a preparation and application method thereof

Abstract

This invention discloses a near-infrared luminescent material responsive to light and force stimuli, and its preparation and application methods. The chemical formula of the near-infrared luminescent material is Mg. 13.7‑a M 1 a Ga 4.6‑b‑x M 2 b Ge 1.7‑ c M 3 c O 24 :xCr 3+ , of which M 1 The element is a combination of one or more of Ca and Sr; M 2 The element is a combination of one or more of Sc and In; M 3 The elements are one or more combinations of Si, Sn, and Ti; 0 < x ≤ 0.9; 0 ≤ a ≤ 1; 0 ≤ b ≤ 0.5; 0 ≤ c ≤ 0.4. This invention's material is a multifunctional near-infrared luminescent material integrating photo- and mechanical stimulation responses, simultaneously possessing photoinduced steady-state near-infrared luminescence, near-infrared long-afterglow luminescence, and near-infrared stress luminescence properties. Under blue and red light excitation, this material exhibits broadband near-infrared luminescence with an emission wavelength range of 600-1200 nm; after ultraviolet irradiation, it exhibits near-infrared long-afterglow luminescence; and under mechanical stimulation, it exhibits broadband near-infrared stress luminescence.

Description

Technical Field

[0001] This invention relates to the field of near-infrared luminescent materials technology, and particularly to a near-infrared luminescent material that responds to light and force stimuli, as well as its preparation and application methods. Background Technology

[0002] Near-infrared (NIR) light, with wavelengths in the 700-2500 nm range, has wide applications in non-destructive quality analysis of agricultural products and non-invasive detection of human physiological states. Because substances such as water, sugars, and fats have different absorption coefficients for NIR light, irradiating biological organisms with NIR light can achieve non-invasive food detection, such as rapidly identifying food freshness and distinguishing between food and additives. Furthermore, given the high overlap between the biological optical windows (first window 650-950 nm, second window 1000-1350 nm, third window 1500-1800 nm) and the NIR band, the strong tissue penetration ability of NIR light can be utilized for non-invasive detection of blood oxygen content and in vivo imaging, among other medical applications. Therefore, high-efficiency broadband NIR luminescent materials have significant research value and broad application prospects.

[0003] With 3D 3 Electronically configured transition metal Cr 3+ Ions are the most ideal activators for achieving broadband near-infrared luminescence. In recent years, Cr... 3+ Doped near-infrared luminescent materials have gradually become one of the research hotspots in the field of inorganic luminescent materials. Researchers have developed many high-performance Cr-doped materials with the main emission peak located in the 700-1120 nm range. 3+ Doped with near-infrared phosphors, such as LaMgGa 11 O 19 :Cr 3+ NaScGe2O6:Cr 3+ LiInSi2O6:Cr 3+ ScBO3:Cr 3+ Ca2LuZr2Al3O 12 :Cr 3+ etc. However, most Cr 3+ Doped near-infrared phosphors can only exhibit steady-state near-infrared luminescence under a single excitation mode, such as photoexcitation, which limits the application of luminescent materials. Long-afterglow luminescence refers to the material's ability to emit light for an extended period after photoexcitation has ceased; stress luminescence is a force-excited luminescence mode, meaning the material can emit light under different mechanical stimuli such as friction, tension, and compression. To further broaden the application fields of luminescent materials, it is crucial to develop multifunctional near-infrared luminescent materials that respond to both light and force stimuli. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing near-infrared luminescent materials with a single stimulus response mode, and to disclose a near-infrared luminescent material that responds to light and force stimuli, as well as its preparation and application methods.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] This invention discloses a near-infrared luminescent material that responds to light and force stimuli, characterized in that it has the general chemical formula Mg. 13.7-a M 1 a Ga 4.6-b-x M 2 b Ge 1.7-c M 3 c O 24 :xCr 3+ , of which M 1 The element is a combination of one or more of Ca and Sr; M 2 The element is a combination of one or more of Sc and In; M 3 The elements are one or more combinations of Si, Sn, and Ti; 0 < x ≤ 0.9; 0 ≤ a ≤ 1; 0 ≤ b ≤ 0.5; 0 ≤ c ≤ 0.4; its crystal structure belongs to the orthorhombic crystal system and the space group is Cmmm.

[0007] Furthermore, the material of the present invention has three excitation peaks located at 250-350nm, 350-540nm and 540-750nm respectively; it can exhibit broadband near-infrared emission under blue and red light excitation, with an emission wavelength range of 600-1200nm, while covering the first (650-950nm) and second windows (1000-1350nm) of bio-optics; the main emission peak range is located at 780-950nm.

[0008] Furthermore, the material of the present invention can exhibit near-infrared long afterglow emission after ultraviolet irradiation, with an afterglow time of more than 30 minutes and an afterglow emission spectrum range of 600-1200 nm.

[0009] Furthermore, the material of the present invention exhibits broadband near-infrared stress luminescence before and after ultraviolet irradiation, and under mechanical stimulation. The stress luminescence spectrum ranges from 600 to 1200 nm, and the luminescence intensity is proportional to the pressure.

[0010] This invention discloses a method for preparing near-infrared luminescent materials that respond to light and force stimuli as described above, characterized by comprising the following steps:

[0011] (1) Weighing materials: Prepare materials according to the stoichiometric ratio of elements, and weigh the materials containing M respectively. 1 carbonates, containing M 2 oxides, containing M3 The oxides, Mg-containing carbonates or oxides, Ga2O3, GeO2, Cr2O3 and appropriate amount of flux are added, and an appropriate amount of anhydrous ethanol is added. After thorough grinding, a mixed powder is obtained.

[0012] (2) Place the mixed powder obtained in step (1) in an alumina crucible and calcine it in a high-temperature box furnace at 1300-1600℃ for 2-6 hours with a heating rate of 2-10℃ / minute. After cooling to room temperature with the furnace, grind the sintered body into powder to obtain a near-infrared luminescent material that responds to light and force stimulation.

[0013] (3) The near-infrared luminescent material that responds to light and force stimulation obtained in step (2) is subjected to a post-processing process to remove impurities.

[0014] Further, in step (1), the flux is at least one of H3BO3, B2O3, alkaline earth metal halide, and alkali metal halide; the content of the flux is 2-7 wt% of the total mass of the raw materials.

[0015] Furthermore, in step (3), the impurity removal process includes acid washing, alkali washing, or water washing.

[0016] This invention also provides the application of the near-infrared luminescent material that responds to light and force stimuli, wherein the application is performed in any one of the following two ways:

[0017] (1) Fabrication of light-emitting device: The light-emitting device is composed of the near-infrared light-emitting material that responds to light and force stimulation, and a blue or red LED chip;

[0018] (2) Preparation of luminescent functional composite material: The luminescent functional composite material is composed of the near-infrared luminescent material that responds to light and force stimulation, and any one of the following base materials: coatings, inks, plastics, fibers, paper, glass, ceramics, concrete, and organic polymer materials; the luminescent functional composite material includes any one of luminescent coatings, luminescent inks, luminescent plastics, luminescent fibers, luminescent paper, luminescent glass, luminescent ceramics, luminescent concrete, and flexible luminescent films. Further, the luminescent device and the luminescent functional composite material are applied in any one of the following scenarios: night vision, non-destructive quality analysis of agricultural products, non-invasive detection of human physiological states, bio-stress imaging, disease monitoring, structural health diagnosis, and anti-counterfeiting encryption.

[0019] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0020] The material of this invention is a multifunctional near-infrared luminescent material that integrates light and force stimulation response, and simultaneously possesses photoinduced steady-state near-infrared luminescence, near-infrared long afterglow luminescence, and near-infrared stress luminescence properties.

[0021] The photoluminescence, long-afterglow luminescence, and stress luminescence properties of the material of this invention are renewable and can be reused.

[0022] The material of this invention has a wide excitation spectrum coverage, with three excitation peaks located at 250-350nm, 350-540nm, and 540-750nm, respectively.

[0023] The photoluminescence, long-afterglow emission, and stress emission spectral range of the material of this invention are 600-1200 nm, and it also covers the first and second windows of biooptics.

[0024] The material of this invention can be applied to night vision, non-destructive quality analysis of agricultural products, non-invasive detection of human physiological states, bio-stress imaging, disease monitoring, structural health diagnosis, and anti-counterfeiting encryption. Attached Figure Description

[0025] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Some specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings in an exemplary and non-limiting manner. The same reference numerals in the drawings indicate the same or similar parts or components. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings:

[0026] Figure 1 This is a powder X-ray diffraction pattern of the sample in Example 1 of the present invention.

[0027] Figure 2 This is the excitation spectrum of the sample in Example 1 of the present invention.

[0028] Figure 3 This is the emission spectrum of the sample in Example 1 of the present invention.

[0029] Figure 4 This is a graph showing the afterglow decay curve of the sample in Example 1 of the present invention.

[0030] Figure 5 This is the stress emission spectrum of the sample in Example 1 of the present invention.

[0031] Figure 6 A photograph of a finger after being illuminated by the light-emitting device prepared for the sample of Example 1 of the present invention in a dark environment.

[0032] Figure 7 This is a photograph of the flexible luminescent film prepared for the sample in Example 1 of the present invention under mechanical tearing.

[0033] Figure 8 This is a powder X-ray diffraction pattern of the sample in Example 2 of the present invention.

[0034] Figure 9 This is the excitation spectrum of the sample in Example 2 of the present invention.

[0035] Figure 10 This is the emission spectrum of the sample in Example 2 of the present invention.

[0036] Figure 11 This is a graph showing the afterglow decay curve of the sample in Example 2 of the present invention.

[0037] Figure 12 This is the stress emission spectrum of the sample in Example 2 of the present invention.

[0038] Figure 13 This is a photograph of the light-emitting device prepared for the sample of Example 2 of the present invention after being illuminated by pliers in a dark environment.

[0039] Figure 14 This is a photograph of the flexible luminescent film prepared for the sample in Example 2 of the present invention under mechanical stretching. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0041] Example 1

[0042] The chemical composition of this embodiment is Mg. 13.7 Ga 4.57 Ge 1.7 O 24 0.03Cr 3+ The preparation method of near-infrared luminescent materials is as follows:

[0043] According to the chemical formula Mg 13.7 Ga 4.57 Ge 1.7 O 24 0.03Cr 3+ According to the stoichiometric ratio, high-purity powder raw materials of MgO, Ga2O3, GeO2, and Cr2O3 were weighed separately, and 5wt% H3BO3 was added as a flux. The mixed powder was placed in an agate mortar and an appropriate amount of anhydrous ethanol was added for grinding to ensure thorough and uniform mixing. The mixed raw materials were transferred to an alumina crucible and sintered in a high-temperature box furnace at 1400℃ for 4 hours. After the sample cooled to room temperature, it was removed, ground into powder again, and acid-washed to remove impurities, thus obtaining MgO. 13.7 Ga 4.57 Ge 1.7 O 24 0.03Cr 3+ Near-infrared luminescent materials.

[0044] The powder X-ray diffraction pattern of the near-infrared luminescent material prepared in this embodiment is as follows: Figure 1 As shown, the excitation spectrum is as follows Figure 2 As shown, the emission spectrum is as follows Figure 3 As shown, the afterglow decay curve is as follows: Figure 4 As shown, the stress emission spectrum is as follows Figure 5 As shown, the excitation spectrum exhibits three distinct excitation peaks, located at 250-350 nm, 350-540 nm, and 540-750 nm, respectively. Under 450 nm blue light excitation, it displays broadband near-infrared emission with an emission peak at 790 nm, covering an emission range of 600-1200 nm. After ultraviolet irradiation, it exhibits near-infrared long-afterglow emission with an afterglow time exceeding 30 minutes. Under a 20 N stress load, it displays broadband near-infrared stress emission. The slight difference in peak positions between photoinduced steady-state emission and stress emission is due to variations in the probes of different testing instruments. This material is thus a multifunctional near-infrared luminescent material responsive to both light and force stimuli. The photoinduced steady-state emission, long-afterglow emission, and stress emission properties of this material are renewable and reusable.

[0045] The near-infrared luminescent material prepared in this embodiment can be combined with blue or red LED chips to prepare near-infrared luminescent devices; it can also be combined with coatings, inks, plastics, fibers, paper, glass, ceramics, concrete or organic polymer materials to prepare luminescent functional composite materials, including luminescent coatings, luminescent inks, luminescent plastics, luminescent fibers, luminescent paper, luminescent glass, luminescent ceramics, luminescent concrete and flexible luminescent films.

[0046] The aforementioned luminescent devices and luminescent functional composite materials can be applied to any of the following scenarios: night vision, non-destructive quality analysis of agricultural products, non-invasive detection of human physiological states, bio-stress imaging, disease monitoring, structural health diagnosis, and anti-counterfeiting encryption. Near-infrared light, due to its advantages such as being invisible to the human eye, exhibiting characteristic absorption by functional groups of organic molecules, and possessing strong penetrating power, has wide applications in night vision, non-destructive quality analysis of agricultural products, non-invasive detection of human physiological states, and anti-counterfeiting encryption. By illuminating objects, food, and biological organisms with the near-infrared light emitted by the prepared near-infrared luminescent devices, and using a near-infrared camera or based on the near-infrared transmission / absorption spectrum, applications such as night vision, non-destructive quality analysis of agricultural products, and non-invasive detection of human physiological states can be achieved. For the prepared luminescent functional composite materials, after ultraviolet light irradiation, by using a near-infrared camera, night vision device, or based on the near-infrared transmission / absorption spectrum, the emitted near-infrared long-afterglow luminescence can achieve applications such as night vision, non-destructive quality analysis of agricultural products, non-invasive detection of human physiological states, and anti-counterfeiting encryption. For the prepared luminescent functional composite materials, such as luminescent fibers and flexible luminescent films, various mechanical stimuli (such as tension, compression, bending, ultrasound, impact, etc.) can be applied to them. With the help of near-infrared cameras, night vision devices, or based on near-infrared transmission / absorption spectra, applications such as bio-stress imaging, disease monitoring, structural health diagnosis, and anti-counterfeiting encryption can be realized. Figure 6 The image obtained by illuminating a finger in a dark environment using the prepared light-emitting device and then taking a picture with a near-infrared camera further demonstrates its application in the field of non-invasive detection of human physiological state. Figure 7 The photo taken by the prepared flexible luminescent film under mechanical tearing using a night vision device can be used to realize applications such as anti-counterfeiting and encryption by utilizing the near-infrared light emitted by it.

[0047] Example 2

[0048] The chemical composition of this embodiment is Mg. 13.5 Ca 0.2 Ga 4.1 In 0.2 Ge 1.7 O 24 0.3Cr 3+ The preparation method of near-infrared luminescent materials is as follows:

[0049] According to the chemical formula Mg 13.5 Ca 0.2 Ga 4.1 In 0.2 Ge 1.7 O 24 0.3Cr 3+According to the stoichiometric ratio, high-purity powder raw materials of MgO, Ga2O3, GeO2, and Cr2O3 were weighed separately, and 3wt% H3BO3 was added as a flux. The mixed powder was placed in an agate mortar and ground with an appropriate amount of anhydrous ethanol to ensure thorough and uniform mixing. The mixed raw materials were transferred to an alumina crucible and sintered in a high-temperature box furnace at 1450℃ for 5 hours. After the sample cooled to room temperature, it was removed, ground again into powder, and acid-washed to remove impurities, thus obtaining MgO. 13.5 Ca 0.2 Ga 4.1 In 0.2 Ge 1.7 O 24 0.3Cr 3+ Near-infrared luminescent materials.

[0050] The powder X-ray diffraction pattern of the near-infrared luminescent material prepared in this embodiment is as follows: Figure 8 As shown, the excitation spectrum is as follows Figure 9 As shown, the emission spectrum is as follows Figure 10 As shown, the afterglow decay curve is as follows: Figure 11 As shown, the stress emission spectrum is as follows Figure 12 As shown, the excitation spectrum exhibits three distinct excitation peaks, located at 250-350 nm, 350-540 nm, and 540-750 nm, respectively. Under 450 nm blue light excitation, it displays broadband near-infrared emission with an emission peak at 890 nm, covering an emission range of 600-1200 nm. After ultraviolet irradiation, it exhibits near-infrared long-afterglow emission with an afterglow time exceeding 30 minutes. Under a 20 N stress load, it displays broadband near-infrared stress emission. The slight difference in peak positions between photoinduced steady-state emission and stress emission is due to variations in the probes of different testing instruments. This material is thus a multifunctional near-infrared luminescent material responsive to both light and force stimuli. The photoinduced steady-state emission, long-afterglow emission, and stress emission properties of this material are renewable and reusable.

[0051] The near-infrared luminescent material prepared in this embodiment can be combined with blue or red LED chips to prepare near-infrared luminescent devices; it can also be combined with coatings, inks, plastics, fibers, paper, glass, ceramics, concrete or organic polymer materials to prepare luminescent functional composite materials, including luminescent coatings, luminescent inks, luminescent plastics, luminescent fibers, luminescent paper, luminescent glass, luminescent ceramics, luminescent concrete and flexible luminescent films.

[0052] The aforementioned luminescent devices and luminescent functional composite materials can be applied to any of the following scenarios: night vision, non-destructive quality analysis of agricultural products, non-invasive detection of human physiological states, bio-stress imaging, disease monitoring, structural health diagnosis, and anti-counterfeiting encryption. Near-infrared light, due to its advantages such as being invisible to the human eye, exhibiting characteristic absorption by functional groups of organic molecules, and possessing strong penetrating power, has wide applications in night vision, non-destructive quality analysis of agricultural products, non-invasive detection of human physiological states, and anti-counterfeiting encryption. By illuminating objects, food, and biological organisms with the near-infrared light emitted by the prepared near-infrared luminescent devices, and using a near-infrared camera or based on the near-infrared transmission / absorption spectrum, applications such as night vision, non-destructive quality analysis of agricultural products, and non-invasive detection of human physiological states can be achieved. For the prepared luminescent functional composite materials, after ultraviolet light irradiation, by using a near-infrared camera, night vision device, or based on the near-infrared transmission / absorption spectrum, the emitted near-infrared long-afterglow luminescence can achieve applications such as night vision, non-destructive quality analysis of agricultural products, non-invasive detection of human physiological states, and anti-counterfeiting encryption. For the prepared luminescent functional composite materials, such as luminescent fibers and flexible luminescent films, various mechanical stimuli (such as tension, compression, bending, ultrasound, impact, etc.) can be applied to them. With the help of near-infrared cameras, night vision devices, or based on near-infrared transmission / absorption spectra, applications such as bio-stress imaging, disease monitoring, structural health diagnosis, and anti-counterfeiting encryption can be realized. Figure 13 The image obtained by illuminating pliers in a dark environment using the prepared light-emitting device and then taking a picture with a near-infrared camera further demonstrates its application in the field of night vision. Figure 14 The photos taken with a night vision device using the flexible luminescent film under mechanical stretching can be used to achieve applications in anti-counterfeiting and encryption by utilizing the emitted near-infrared light.

[0053] In Examples 3 to 10, the required raw materials were weighed according to the chemical composition formula and stoichiometric ratio in Table 1. The preparation method was the same as in Example 1. The chemical composition, sintering temperature, sintering time, photoluminescence steady-state emission and stress emission spectral peaks of the synthesized samples are listed in the table below.

[0054]

[0055] The above description is only a part of the specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the protection scope of the present invention.

Claims

1. A near-infrared luminescent material responsive to light and force stimuli, characterized in that, The chemical formula of the near-infrared luminescent material is Mg. 13.7-a M 1 a Ga 4.6-b-x M 2 b Ge 1.7-c M 3 c O 24 :xCr 3+ , of which M 1 The element is a combination of one or more of Ca and Sr; M 2 The element is a combination of one or more of Sc and In; M 3 The elements are one or more combinations of Si, Sn, and Ti; 0 < x ≤ 0.9; 0 ≤ a ≤ 1; 0 ≤ b ≤ 0.5; 0 ≤ c ≤ 0.4; its crystal structure belongs to the orthorhombic crystal system and the space group is Cmmm.

2. The near-infrared luminescent material responsive to light and force stimuli as described in claim 1, characterized in that, The luminescent material has three excitation peaks located at 250-350 nm, 350-540 nm, and 540-750 nm, respectively; it can exhibit broadband near-infrared emission under blue and red light excitation, with an emission wavelength range of 600-1200 nm; the main emission peak range is located at 780-950 nm.

3. The near-infrared luminescent material responding to light and force stimuli as described in claim 1, characterized in that, The luminescent material exhibits near-infrared long afterglow emission after ultraviolet irradiation, with an afterglow time greater than 30 minutes and an afterglow emission spectrum range of 600-1200 nm.

4. The near-infrared luminescent material responsive to light and force stimuli as described in claim 1, characterized in that, The luminescent material exhibits broadband near-infrared stress luminescence before and after ultraviolet irradiation, and under mechanical stimulation, with a stress luminescence spectrum range of 600-1200 nm.

5. The method for preparing a near-infrared luminescent material responsive to light and force stimuli as described in claim 1, characterized in that, Includes the following steps: (1) Weighing the material: according to the general chemical formula Mg 13.7-a M 1 a Ga 4.6-b-x M 2 b Ge 1.7-c M 3 c O 24 :xCr 3+ In the middle, Mg, M 1 Ga, M 2 Ge, M 3 The ingredients were prepared according to the stoichiometric ratio of Cr and M, and the amounts of M were weighed separately. 1 carbonates, containing M 2 oxides, containing M 3 The oxides, Mg-containing carbonates or oxides, Ga2O3, GeO2, Cr2O3 and appropriate amount of flux are added, and an appropriate amount of anhydrous ethanol is added. After thorough grinding, a mixed powder is obtained. (2) Place the mixed powder obtained in step (1) in an alumina crucible and calcine it in a high-temperature box furnace at 1300-1600℃ for 2-6 hours with a heating rate of 2-10℃ / minute. After cooling to room temperature with the furnace, a sintered body is obtained. The sintered body is then ground into powder to obtain a near-infrared luminescent material that responds to light and force stimulation. (3) The near-infrared luminescent material that responds to light and force stimulation obtained in step (2) is subjected to a post-processing process to remove impurities.

6. The method for preparing a near-infrared luminescent material responsive to light and force stimuli as described in claim 5, characterized in that, In step (1), the flux is one or more combinations of H3BO3, B2O3, alkaline earth metal halides and alkali metal halides; the content of the flux is 2-7 wt% of the total mass of the mixed powder.

7. The method for preparing a near-infrared luminescent material responsive to light and force stimuli as described in claim 5, characterized in that, In step (3), the impurity removal process includes acid washing, alkali washing or water washing.

8. The application of the near-infrared luminescent material responsive to light and force stimuli as described in any one of claims 1 to 4, characterized in that, Apply it in either of the following two: (1) Fabrication of light-emitting device: The light-emitting device is composed of the near-infrared light-emitting material that responds to light and force stimulation, and a blue or red LED chip; (2) Preparation of luminescent functional composite material: The luminescent functional composite material is composed of the near-infrared luminescent material that responds to light and force stimulation, and any one of the following base materials: coating, ink, plastic, fiber, paper, glass, ceramic, concrete, organic polymer; The luminescent functional composite material includes any one of luminescent coating, luminescent ink, luminescent plastic, luminescent fiber, luminescent paper, luminescent glass, luminescent ceramic, luminescent concrete, and flexible luminescent film.

9. The application of the near-infrared luminescent material responsive to light and force stimuli as described in claim 8, characterized in that, The light-emitting device and the light-emitting composite material can be applied to any of the following scenarios: night vision, non-destructive quality analysis of agricultural products, bio-stress imaging, and anti-counterfeiting encryption.

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