Long-wavelength garnet near-infrared luminescent material, preparation method and application thereof

Abstract

The application belongs to the technical field of luminescent materials, and discloses a long-wavelength garnet near-infrared luminescent material and a preparation method and application thereof. x Ca 3‑2x M 1 x M 2 2‑ y Cr y Ge3O 12 ; M 1 is at least one selected from La, Gd, Y or Lu; M 2 is at least one selected from In or Sc; 0

Description

Technical Field

[0001] This invention belongs to the field of luminescent materials technology, and more specifically, relates to a long-wavelength garnet near-infrared luminescent material, its preparation method, and its application. Background Technology

[0002] In recent years, near-infrared light sources and spectral analysis detection technologies based on fluorescent conversion light-emitting diodes (LEDs) have been widely applied in modern agriculture, biomedicine, security monitoring, facial recognition, food quality inspection, photovoltaics, and other fields. Their specific applications depend on the emission wavelength of the light source device. The output spectrum and efficiency of the light source device, in turn, depend on the near-infrared emitting material. Therefore, developing high-efficiency near-infrared emitting materials in different wavelength bands to meet the application needs of various fields has significant research value and broad application prospects.

[0003] Among numerous near-infrared luminescent materials, Cr 3+ Garnet-doped near-infrared materials often attract attention due to their excellent luminescence efficiency, such as the Ca3Sc2Si3O developed by Liu Yongfu's team at the Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences. 12 :Cr 3+ With an internal quantum efficiency as high as 92.3% (Light Sci. Appl. 2020, 9(1), 86), it has great commercial potential. However, due to the dense atomic packing of garnet compounds, the crystal field strength is too strong, resulting in the emission peak wavelength of most garnet materials being less than 830 nm, which greatly limits the application of such materials in the long-wavelength band. Therefore, developing garnet materials with peak wavelengths greater than 830 nm has important practical significance. Summary of the Invention

[0004] To address the shortcomings and drawbacks of the existing technology, the primary objective of this invention is to provide a long-wavelength garnet near-infrared luminescent material. This material emits near-infrared light with a tunable peak wavelength of 831–916 nm when excited by 460 nm blue light, and can be used as a luminescent material for near-infrared PC-LEDs based on fluorescence conversion.

[0005] Another object of the present invention is to provide a method for preparing the above-mentioned long-wavelength garnet near-infrared luminescent material.

[0006] Another object of the present invention is to provide applications of the above-mentioned long-wavelength garnet near-infrared luminescent material.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] A long-wavelength garnet near-infrared luminescent material, wherein the chemical formula of the luminescent material is Na. x Ca 3-2x M 1x M 2 2- y Cr y Ge3O 12 ;M 1 at least one selected from La, Gd, Y or Lu; M 2 at least one selected from In or Sc; 0 < x < 1.5, and 0 < y < 0.2.

[0009] Preferably, the luminescent material is Na 1.5 Gd 1.5 In 1.94 Cr 0.06 Ge3O 12 , Na 1.5 Gd 1.5 Sc 1.94 Cr 0.06 Ge3O 12 , Na 0.3 Ca 2.4 Gd 0.3 In 1.94 Cr 0.06 Ge3O 12 , Na 0.6 Ca 1.8 Gd 0.6 In 1.94 Cr 0.06 Ge3O 12 , Na 0.9 Ca 1.2 Gd 0.9 In 1.94 Cr 0.06 Ge3O 12 , Na 1.2 Ca 0.6 Gd 1.2 In 1.94 Cr 0.06 Ge3O 12 .

[0010] The preparation method of the long-wavelength garnet near-infrared luminescent material comprises the following specific steps:

[0011] S1. finely mixing and uniformly mixing M 1 compound, M 2 compound, Na compound, Ge compound, Cr compound and / or Ca compound to obtain a mixture;

[0012] S2. sintering the mixture at 1200-1400℃ in air, and crushing and finely processing the product to obtain the long-wavelength garnet near-infrared luminescent material.

[0013] Preferably, the M 1 The compound is one or more of lanthanum oxide, lanthanum hydroxide, lanthanum chloride, gadolinium oxide, gadolinium hydroxide, gadolinium chloride, yttrium oxide, yttrium hydroxide, yttrium chloride, lutetium oxide, lutetium hydroxide or lutetium chloride; the M 2 The compound is indium oxide or / and scandium oxide; the Na compound is one or more of sodium carbonate, sodium oxide or sodium hydroxide; the Ca compound is one or more of calcium carbonate, calcium oxide or calcium hydroxide; the Ge compound is germanium dioxide; the Cr compound is chromium oxide or / and chromium nitrate.

[0014] Preferably, the sintering time in step S2 is 4-48h.

[0015] Application of the long-wavelength garnet near-infrared luminescent material in a light conversion device.

[0016] Preferably, the light conversion device is a near-infrared LED device.

[0017] The long-wavelength garnet near-infrared luminescent material of the present application belongs to a new component compound in a classical garnet structure, and is a garnet material with an excitation peak wavelength of 460-480nm and an emission peak wavelength of 831-916nm, which is obtained by doping optical active element Cr 3+ dissolved in Ca 3-2x Na x M 1 x M 2 2Ge3O 12 (M 1 =La,Gd,Y,Lu;M 2 =Sc,In) solid solution, and exhibits excellent comprehensive performance, with a relative luminescent intensity of 60% or more, and has potential application value.

[0018] The present application obtains near-infrared materials with a large range of adjustable emission wavelengths by designing different proportions of [Na + -La 3+ ], [Na + -Gd 3+ ], [Na + -Y 3+ ] and [Na + -Lu 3+ ] equivalent substitution of [Ca 2+ -Ca 2+ ], which mainly benefits from the introduction of different degrees of Jahn-Teller distortion, so that the energy level splitting degree can be adjusted. This method is different from the traditional realization method of changing the crystal field strength, and is conducive to maintaining the blue light excitation of the material. In addition, the present application preferably contains Gd 3+The main reason is that the ionic radius of Gd 3+ + The ionic radius of Gd 2+ The ionic radius of Gd 1.5 1.5 1.94 0.06 12 1.5 1.5 1.94 0.06 12 1.5 1.5 1.94 0.06 12 1.5 1.5 1.94 0.06 The main reason is that the ionic radius of Gd

[0019] Compared with the prior art, the present application has the following beneficial effects:

[0020] 1. The garnet near-infrared luminescent material provided by the present application can be effectively excited by blue light and red light in the range of 450-550 nm and 600-750 nm, and the excitation peak wavelength is located in the range of 460-480 nm, which can be applied to commercial blue LED chips, and has strong practicability.

[0021] 2. The garnet near-infrared luminescent material provided by the present application emits near-infrared light with a peak wavelength of 831-916 nm tunable under 460 nm blue light excitation, and the peak wavelength of the luminescence breaks through 900 nm for the first time in the garnet system, which can be used as a luminescent material for fluorescent conversion near-infrared pc-LED.

[0022] 3. The synthesis temperature of the garnet near-infrared luminescent material provided by the present application is lower than that of most garnet materials, the preparation process is simple, special reaction equipment is not required, and industrial production is convenient. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The X-ray powder diffraction pattern of Na 1.5 Gd 1.5 In 1.94 Cr 0.06 Ge3O 12 in Example 1.

[0024] Figure 2 The excitation spectrum of Na 1.5 Gd 1.5 In 1.94 Cr 0.06 Ge3O 12 in Example 1.

[0025] Figure 3 The emission spectrum of Na 1.5 Gd 1.5 In 1.94 Cr 0.06 Ge3O 12 in Example 1.

[0026] Figure 4 The X-ray powder diffraction pattern of Na 1.5 Gd 1.5 Sc 1.94 Cr 0.06 Ge3O12 X-ray powder diffraction pattern.

[0027] Figure 5 Na in Example 2 1.5 Gd 1.5 Sc 1.94 Cr 0.06 Ge3O 12 The excitation spectrum.

[0028] Figure 6 Na in Example 2 1.5 Gd 1.5 Sc 1.94 Cr 0.06 Ge3O 12 The emission spectrum.

[0029] Figure 7 Na in Example 3 0.3 Ca 2.4 Gd 0.3 In 1.94 Cr 0.06 Ge3O 12 The emission spectrum.

[0030] Figure 8 Na in Example 4 0.6 Ca 1.8 Gd 0.6 In 1.94 Cr 0.06 Ge3O 12 The emission spectrum.

[0031] Figure 9 Na in Example 5 0.9 Ca 1.2 Gd 0.9 In 1.94 Cr 0.06 Ge3O 12 The emission spectrum.

[0032] Figure 10 Na in Example 6 1.2 Ca 0.6 Gd 1.2 In 1.94 Cr 0.06 Ge3O 12 The emission spectrum. Detailed Implementation

[0033] The present invention will be further described below with reference to specific embodiments, but these should not be construed as limiting the invention. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in this technical field.

[0034] Example 1

[0035] According to the chemical formula of the luminescent material Na 1.5 Gd 1.5 In 1.94 Cr 0.06 Ge3O 12 0.1575 mol NaHCO3, 0.075 mol Gd2O3, 0.097 mol In2O3, 0.3 mol GeO2, and 0.003 mol Cr2O3 of analytical grade were weighed and mixed. The mixture was then thoroughly ground in an agate mortar for 30 minutes until homogeneous. The mixture was then placed in an alumina crucible and calcined at 1300℃ for 6 hours. After cooling to room temperature, the product was crushed, ground, washed, and dried to obtain Na. 1.5 Gd 1.5 In 1.94 Cr 0.06 Ge3O 12 Luminescent materials. Figure 1 Na, as in Example 1 1.5 Gd 1.5 In 1.94 Cr 0.06 Ge3O 12 X-ray powder diffraction pattern (Cu target, λ = 0.15406 nm). From Figure 1 It is known that the material has a garnet structure. Figure 2 Na in Example 1 1.5 Gd 1.5 In 1.94 Cr 0.06 Ge3O 12 The excitation spectrum. (From) Figure 2 It can be seen that, under 916nm monitoring, the luminescent material can be effectively excited by blue and red light in the range of 350–750nm, with the main excitation peak located at 480nm. Figure 3 Na, as in Example 1 1.5 Gd 1.5 In 1.94 Cr 0.06 Ge3O 12 The emission spectrum covers 700–1400 nm, with the main emission peak at 916 nm. Under excitation with 460 nm blue light, the relative luminescence intensity is 64% (see Table 1).

[0036] Example 2

[0037] According to the chemical formula of the luminescent material Na 1.5 Gd 1.5 Sc 1.94 Cr 0.06 Ge3O 120.1575 mol NaHCO3, 0.075 mol Gd2O3, 0.097 mol Sc2O3, 0.3 mol GeO2, and 0.003 mol Cr2O3 of analytical grade were weighed and mixed. The mixture was then thoroughly ground in an agate mortar for 30 minutes until homogeneous. The mixture was then placed in an alumina crucible and calcined at 1300℃ for 8 hours. After cooling to room temperature, the product was crushed, ground, washed, and dried to obtain Na. 1.5 Gd 1.5 Sc 1.94 Cr 0.06 Ge3O 12 Luminescent materials. Figure 4 Na in Example 2 1.5 Gd 1.5 Sc 1.94 Cr 0.06 Ge3O 12 X-ray powder diffraction pattern (Cu target, λ = 0.15406 nm). Figure 5 The excitation spectrum in Example 2 is derived from... Figure 5 It can be seen that the excitation spectrum is at 864nNa 1.5 Gd 1.5 Sc 1.94 Cr 0.06 Ge3O 12 Under m monitoring, the luminescent material can be effectively excited by blue and red light in the range of 350–750 nm, with the main excitation peak located at 467 nm. Figure 6 Na in Example 2 1.5 Gd 1.5 Sc 1.94 Cr 0.06 Ge3O 12 The emission spectrum of the device covers the range of 700-1400 nm, with the main emission peak located at 864 nm (see Table 1).

[0038] Example 3

[0039] According to the chemical formula of the luminescent material Na 0.3 Ca 2.4 Gd 0.3 In 1.94 Cr 0.06 Ge3O 12 0.0315 mol NaHCO3, 0.24 mol CaCO3, 0.015 mol Gd2O3, 0.097 mol In2O3, 0.3 mol GeO2, and 0.003 mol Cr2O3 of analytical grade were weighed and mixed. The mixture was then thoroughly ground in an agate mortar for 30 minutes until homogeneous. The mixture was then placed in an alumina crucible and calcined at 1300℃ for 6 hours. After cooling to room temperature, the product was crushed, ground, washed, and dried to obtain Na. 0.3Ca 2.4 Gd 0. 3In 1.94 Cr 0.06 Ge3O 12 luminescent material. Figure 7 Na 0.3 Ca 2.4 Gd 0.3 In 1.94 Cr 0.06 Ge3O 12 with emission spectrum covering 700-1300 nm and main emission peak at 831 nm. Under 460 nm excitation, the relative luminescent intensity is 86% (see Table 1).

[0040] Example 4

[0041] Na 0.6 Ca 1.8 Gd 0.6 In 1.94 Cr 0.06 Ge3O 12 , analytical pure 0.063 mol NaHCO3, 0.18 mol CaCO3, 0.03 mol Gd2O3, 0.097 mol In2O3, 0.3 mol GeO2 and 0.003 mol Cr2O3 were weighed and mixed, and then ground in an agate mortar for 30 min until well mixed. The mixture was then loaded into an alumina crucible and calcined at 1300°C for 6 h. After cooling to room temperature, the product was treated by crushing, grinding, washing and drying to obtain the luminescent material Na 0.6 Ca 1.8 Gd 0.6 In 1.94 Cr 0.06 Ge3O 12 . Figure 8 Na 0.6 Ca 1.8 Gd 0.6 In 1.94 Cr 0.06 Ge3O 12 with emission spectrum covering 700-1350 nm and main emission peak at 858 nm. Under 460 nm excitation, the relative luminescent intensity is 91% (see Table 1).

[0042] Example 5

[0043] Na 0.9 Ca 1.2 Gd 0.9 In 1.94 Cr 0.06 Ge3O12 0.0945 mol NaHCO3, 0.12 mol CaCO3, 0.045 mol Gd2O3, 0.097 mol In2O3, 0.3 mol GeO2, and 0.003 mol Cr2O3 of analytical grade were weighed and mixed. The mixture was then thoroughly ground in an agate mortar for 30 minutes until homogeneous. The mixture was then placed in an alumina crucible and calcined at 1300℃ for 6 hours. After cooling to room temperature, the product was crushed, ground, washed, and dried to obtain Na. 0.9 Ca 1.2 Gd 0.9 In 1.94 Cr 0.06 Ge3O 12 Luminescent materials. Figure 9 Na in Example 5 0.9 Ca 1.2 Gd 0.9 In 1.94 Cr 0.06 Ge3O 12 The emission spectrum of this material covers the range of 700–1400 nm, with the main emission peak located at 886 nm. Under 460 nm excitation, the relative luminescence intensity is 100% (see Table 1).

[0044] Example 6

[0045] According to the chemical formula of the luminescent material Na 1.2 Ca 0.6 Gd 1.2 In 1.94 Cr 0.06 Ge3O 12 0.126 mol NaHCO3, 0.06 mol CaCO3, 0.06 mol Gd2O3, 0.097 mol In2O3, 0.3 mol GeO2, and 0.003 mol Cr2O3 of analytical grade were weighed and mixed. The mixture was then thoroughly ground in an agate mortar for 30 minutes until homogeneous. The mixture was then placed in an alumina crucible and calcined at 1300℃ for 6 hours. After cooling to room temperature, the product was crushed, ground, washed, and dried to obtain Na. 1.2 Ca 0.6 Gd 1.2 In 1.94 Cr 0.06 Ge3O 12 Luminescent materials. Figure 10 Na in Example 6 1.2 Ca 0.6 Gd 1.2 In 1.94 Cr 0.06 Ge3O 12The emission spectrum of the luminescent material covers 750-1400 nm, and the main emission peak is at 901 nm. Under 460 nm excitation, the relative luminescent intensity is 75% (see Table 1).

[0046] Example 7

[0047] The luminescent material is of the chemical formula Na 1.5 Y 1.5 Sc 1.94 Cr 0.06 Ge3O 12 The analytical pure 0.1575 mol NaHCO3, 0.075 mol Y2O3, 0.097 mol Sc2O3, 0.3 mol GeO2 and 0.003 mol Cr2O3 are weighed, mixed and ground in a agate mortar for 30 min until uniform, then loaded into an alumina crucible and calcined at 1250°C for 8 h. After cooling to room temperature, the product is broken, ground, washed and dried to obtain the luminescent material of the chemical formula Na 1.5 Y 1.5 Sc 1.94 Cr 0.06 Ge3O 12 The emission spectrum of the luminescent material covers 750-1200 nm, and the main emission peak is at 840 nm (see Table 1).

[0048] Table 1 The main emission peak position and relative luminescent intensity of the luminescent materials prepared in Examples 1-7 under 460 nm excitation

[0049]

[0050] The above examples are the preferred embodiments of the present application, but the embodiments of the present application are not limited by the above examples, and any changes, modifications, substitutions, combinations and simplifications made without departing from the spirit and principles of the present application shall be equivalent replacement modes, and all shall be included in the protection scope of the present application.

Claims

1. A long wavelength garnet near infrared luminescent material, characterized in that, The chemical formula of the luminescent material is Na x Ca 3- 2x M 1 x M 2 2-y Cr y Ge3O 12 ; M 1 at least one selected from Gd or Y; M 2 at least one selected from In or Sc; 0 x ≤1.5, and 0 y ≤0.2; the excitation peak wavelength of the luminescent material is 460-480 nm, and the emission peak wavelength is 831-916 nm.

2. The long wavelength garnet near infrared luminescent material of claim 1, wherein, The luminescent material is Na 1.5 Gd 1.5 In 1.94 Cr 0.06 Ge3O 12 , Na 1.5 Gd 1.5 Sc 1.94 Cr 0.06 Ge3O 12 , Na 0.3 Ca 2.4 Gd 0.3 In 1.94 Cr 0.06 Ge3O 12 , Na 0.6 Ca 1.8 Gd 0.6 In 1.94 Cr 0.06 Ge3O 12 , Na 0.9 Ca 1.2 Gd 0.9 In 1.94 Cr 0.06 Ge3O 12 , Na 1.2 Ca 0.6 Gd 1.2 In 1.94 Cr 0.06 Ge3O 12 .

3. The method for preparing long-wavelength garnet near-infrared luminescent material according to claim 1 or 2, characterized in that, The method comprises the following specific steps: S1. Mix M 1 compound, M 2 compound, Na compound, Ge compound, Cr compound and / or Ca compound are mixed uniformly to obtain a mixture; S2. Sintering the mixture at 1200-1400 DEG C in air, and crushing and grinding the product to obtain long-wavelength garnet near-infrared luminescent material.

4. The method of claim 3, wherein the long wavelength garnet near infrared luminescent material is prepared by the following steps of: The M 1 The compound is one or more of gadolinium oxide, gadolinium hydroxide, gadolinium chloride, yttrium oxide, yttrium hydroxide, or yttrium chloride; the M 2 The compound is indium oxide and / or scandium oxide; the Na compound is one or more of sodium carbonate, sodium oxide, or sodium hydroxide; the Ca compound is one or more of calcium carbonate, calcium oxide, or calcium hydroxide; the Ge compound is germanium dioxide; and the Cr compound is chromium oxide and / or chromium nitrate. ​ 5. The method of claim 3, wherein the long wavelength garnet near infrared luminescent material is prepared by the following steps of: The sintering time in step S2 is 4-48 h. ​ 6. Application of the long-wavelength garnet near-infrared luminescent material in claim 1 or 2 to a light conversion device.

7. Use according to claim 6, characterized in that, The light conversion device is a near-infrared LED device.

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