Ni < 2 + >-doped broadband short-wave near-infrared fluorescent powder as well as preparation method and application thereof

Abstract

The invention relates to Ni < 2 + >-doped broadband short-wave near-infrared fluorescent powder as well as a preparation method and application thereof, and belongs to the technical field of fluorescent materials. The chemical general formula of the Ni < 2 + >-doped broadband short-wave near-infrared fluorescent powder is LiMg2Al9O16: xNi < 2 + >, wherein x is more than or equal to 0.01 and less than or equal to 0.05; the fluorescent powder substrate is of a spinel structure, the fluorescent powder emits short-wave near-infrared light with the peak value of 900-1600 nm under excitation of visible light with the wavelength of 250-750 nm, and the half-peak width of an emission spectrum is 200-250 nm. As the spinel structure of LiMg2Al9O16 contains about 3% of Mg 'Al and Al.Mg antisite defects, two octahedral lattice sites of [Mg-O] 6 and [Al-O] 6 are formed, and ultra-wideband Ni < 2 + > near-infrared emission with the central wavelength of 1,180 nm and the half-peak width of 210 nm can be generated under excitation of 370 nm. The fluorescent powder has the advantages of simplicity and convenience in synthesis, good thermal stability, low required energy consumption and the like, and can solve the problems of poor stability and complex synthesis conditions in the prior art.

Description

Technical Field

[0001] The present invention relates to a Ni 2+ The invention discloses a doped broadband short-wave near-infrared phosphor and a preparation method and application thereof, belonging to the technical field of fluorescent materials. Background Art

[0002] At present, the commonly used short-wave infrared (SWIR) light sources in the field of spectral analysis include incandescent halogen lamps, lasers and LEDs, but each of them has specific advantages and disadvantages. Halogen lamps can produce continuous spectrum radiation from visible light to infrared light, but their significant disadvantages include bulky size, short service life, low energy efficiency and high temperature safety hazards. In contrast, although laser diodes or fiber lasers have high radiation intensity, their highly coherent laser beams and narrow emission spectra limit their practicality in industrial applications. In addition, supercontinuum lasers are not suitable for widespread application due to their small divergence angle, high power consumption and relatively high cost. SWIR-LED chips have gradually become a new generation of NIR solid-state light sources due to their small size, high efficiency and long life. However, the relatively narrow spectral coverage (<50nm), low output power and high cost limit their application in the SWIR field. Summary of the invention

[0003] Aiming at the problems of relatively narrow spectral coverage (<50nm), low output power and high cost of existing SWIR-LED chips, the present invention proposes a Ni 2+ Doped broadband short-wave near-infrared phosphor and its preparation method and application, namely, constructing a spinel structure matrix LiMg2Al9O 16 , using Ni 2+ Doping results in the spinel structure containing about 3% Mg′ Al and Al Mg Anti-site defects form two octahedral lattices [Mg-O]6 and [Al-O]6. The oxidation state of nickel ions is very stable, and it exhibits excellent luminescence performance in octahedral coordination and a wide near-infrared emission bandwidth. Under 370nm excitation, it can produce an ultra-wideband Ni with a central wavelength of 1180nm and a half-peak width of 210nm. 2+ Near-infrared emission. The phosphor has the advantages of simple synthesis, good thermal stability, and low energy consumption, and can solve the problems of poor stability and complex synthesis conditions in the existing technology.

[0004] A Ni 2+ Doped broadband short-wave near-infrared phosphor, the general chemical formula is: LiMg2Al9O 16 :xNi 2+, wherein 0.01≤x≤0.05; the phosphor matrix has a spinel structure, and the phosphor emits short-wave near-infrared light with a peak value of 900-1600nm under the excitation of visible light with a wavelength of 250-750nm, and the half-peak width of the emission spectrum is 200-250nm.

[0005] The Ni 2+ The preparation method of the doped broadband short-wave near-infrared phosphor comprises the following specific steps:

[0006] (1) weighing raw materials Li2CO3, Mg(OH)2, Al2O3 and Ni(CH3COO)2 according to a stoichiometric ratio and mixing and grinding to obtain a mixed material;

[0007] (2) In an air atmosphere, the mixture is heated to a temperature of 1200-1400°C and sintered for 6-8 hours, cooled to room temperature, and ground to obtain Ni 2+ Doped broadband short-wave near-infrared phosphor LiMg2Al9O 16 :xNi 2+ .

[0008] The Ni 2+ Application of doped broadband short-wave near-infrared phosphor in the preparation of SWIR-LED devices; specifically, Ni 2+ Doped broadband short-wave near-infrared phosphor LiMg2Al9O 16 :xNi 2+ The phosphor-silica gel mixture is fully mixed with silica gel to obtain a phosphor-silica gel mixture, and then the phosphor-silica gel mixture is dropped onto a 365nm semiconductor chip and dried at a temperature of 100 to 120°C to obtain a SWIR-LED device.

[0009] Preferably, Ni in the phosphor-silica gel mixture 2+ Doped broadband short-wave near-infrared phosphor LiMg2Al9O 16 :xNi 2+ The content is 45-55wt.%.

[0010] The SWIR-LED device can be used for vein imaging or night vision imaging.

[0011] The spinel structure matrix LiMg2Al9O 16 With high chemical, thermal and optical stability, Ni 2+ Belong to 3D 8 Electronic structure, coordinated with oxygen to form octahedral and tetrahedral structures, in the spinel matrix, Ni 2+ and B 3+ With similar ionic radius, Ni 2+ It is easy to replace B 3+into the octahedral lattice, thereby achieving the desired SWIR emission; the single cation Ni 2+ Substitution is used to adjust the crystal field strength and reduce the probability of non-radiative transitions, thereby improving luminescence efficiency and thermal stability.

[0012] The beneficial effects of the present invention are:

[0013] (1) The broadband short-wave near-infrared phosphor of the present invention is an oxide with a spinel structure, multiple lattices, a wide spectral coverage, stable physical and chemical properties, a simple preparation method, and a short reaction time;

[0014] (2) The near-infrared phosphor of the present invention can generate a broadband near-infrared emission peak under 370nm excitation, the emission peak is located in the wavelength range of 900-1600nm, the half-peak width is 210nm, and the strongest emission peak is located at 1180nm, which has the advantages of a wide excitation range and a wide emission peak spectrum;

[0015] (3) The excellent photoelectric properties of the near-infrared phosphor of the present invention enable the prepared pc-NIR LED to show good penetration and night vision imaging, and can be used for venous imaging or night vision imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 LiMg2Al9O prepared in Example 1 16 :0.01Ni 2+ Excitation and emission spectra of phosphors;

[0017] Figure 2 LiMg2Al9O prepared in Example 2 16 :0.02Ni 2+ Excitation and emission spectra of phosphors;

[0018] Figure 3 LiMg2Al9O prepared in Example 3 16 :0.03Ni 2+ Excitation and emission spectra of phosphors;

[0019] Figure 4 LiMg2Al9O prepared in Example 4 16 :0.04Ni 2+ XRD spectrum and standard card of phosphor;

[0020] Figure 5 LiMg2Al9O prepared in Example 4 16 :0.04Ni 2+ The excitation spectrum in ;

[0021] Figure 6 LiMg2Al9O prepared in Example 416 :0.04Ni 2+ Emission spectrum of

[0022] Figure 7 LiMg2Al9O prepared in Example 4 16 :0.04Ni 2+ Attenuation curve under 370nm excitation;

[0023] Figure 8 LiMg2Al9O prepared in Example 4 16 :0.04Ni 2+ Application results in venous imaging;

[0024] Fig. 9 LiMg2Al9O prepared in Example 4 16 :0.04Ni 2+ Application results in night vision imaging; DETAILED DESCRIPTION

[0026] The present invention is further described in detail below in conjunction with specific implementation modes, but the protection scope of the present invention is not limited to the described contents.

[0027] Embodiment 1: This embodiment Ni 2+ Doped broadband short-wave near-infrared phosphor, chemical formula: LiMg2Al9O 16 :0.01Ni 2+ The phosphor matrix LiMg2Al9O 16 It has a spinel structure;

[0028] A Ni 2+ The preparation method of the doped broadband short-wave near-infrared phosphor comprises the following specific steps:

[0029] (1) weighing raw materials Li2CO3, Mg(OH)2, Al2O3 and Ni(CH3COO)2 according to a stoichiometric ratio and mixing and grinding for 30 minutes to obtain a mixed material;

[0030] (2) In an air atmosphere, the mixture was placed in a tube furnace, heated to 1200°C, sintered for 8 h, cooled to room temperature, and ground to obtain Ni 2+ Doped broadband short-wave near-infrared phosphor LiMg2Al9O 16 :0.01Ni 2+ ;

[0031] In this embodiment, Ni 2+ The excitation and emission spectra of the doped broadband short-wave near-infrared phosphors are shown in Figure 1As shown in the figure, under the ultraviolet light excitation of 370nm, the main emission is 1180nm; under the emission monitoring wavelength of 1180nm, the excitation spectrum is composed of excitation bands located at 370nm and 590nm, which are mainly derived from Ni 2+ of 3 A2(F)- 3 T1(P) and 3 A2(F)- 3 T1(F) energy level transition; the half-peak width of the phosphor in this embodiment is 209nm;

[0032] The Ni 2+ Application of doped broadband short-wave near-infrared phosphor in the preparation of SWIR-LED devices; specifically, Ni 2+ Doped broadband short-wave near-infrared phosphor LiMg2Al9O 16 :0.01Ni 2+ Mix with silica gel to obtain phosphor-silica gel mixed solution (Ni in phosphor-silica gel mixed solution) 2+ Doped broadband short-wave near-infrared phosphor LiMg2Al9O 16 :xNi 2+ Then, the phosphor-silica gel mixture is dropped onto a 365nm semiconductor chip and dried at 100°C to obtain a SWIR-LED device.

[0033] Embodiment 2: This embodiment Ni 2+ Doped broadband short-wave near-infrared phosphor, chemical formula: LiMg2Al9O 16 :0.02Ni 2+ The phosphor matrix LiMg2Al9O 16 It has a spinel structure;

[0034] A Ni 2+ The preparation method of the doped broadband short-wave near-infrared phosphor comprises the following specific steps:

[0035] (1) weighing raw materials Li2CO3, Mg(OH)2, Al2O3 and Ni(CH3COO)2 according to a stoichiometric ratio and mixing and grinding for 35 minutes to obtain a mixed material;

[0036] (2) In an air atmosphere, the mixture was placed in a tube furnace, heated to 1250°C, sintered for 7 h, cooled to room temperature, and ground to obtain Ni 2+ Doped broadband short-wave near-infrared phosphor LiMg2Al9O 16 :0.02Ni 2+ ;

[0037] In this embodiment, Ni 2+The excitation and emission spectra of the doped broadband short-wave near-infrared phosphors are shown in Figure 2 As shown in the figure, under the ultraviolet light excitation of 370nm, the main emission is 1180nm; under the emission monitoring wavelength of 1180nm, the excitation spectrum is composed of excitation bands located at 370nm and 590nm, which are mainly derived from Ni 2+ of 3 A2(F)- 3 T1(P) and 3 A2(F)- 3 T1(F) energy level transition; the half-peak width of the phosphor in this embodiment is 209nm;

[0038] The Ni 2+ Application of doped broadband short-wave near-infrared phosphor in the preparation of SWIR-LED devices; specifically, Ni 2+ Doped broadband short-wave near-infrared phosphor LiMg2Al9O 16 :0.02Ni 2+ Mix with silica gel to obtain phosphor-silica gel mixed solution (Ni in phosphor-silica gel mixed solution) 2+ Doped broadband short-wave near-infrared phosphor LiMg2Al9O 16 :0.02Ni 2+ Then, the phosphor-silica gel mixture is dropped onto a 365nm semiconductor chip and dried at 100°C to obtain a SWIR-LED device.

[0039] Embodiment 3: This embodiment Ni 2+ Doped broadband short-wave near-infrared phosphor, chemical formula: LiMg2Al9O 16 :0.03Ni 2+ The phosphor matrix LiMg2Al9O 16 It has a spinel structure;

[0040] A Ni 2+ The preparation method of the doped broadband short-wave near-infrared phosphor comprises the following specific steps:

[0041] (1) weighing raw materials Li2CO3, Mg(OH)2, Al2O3 and Ni(CH3COO)2 according to a stoichiometric ratio and mixing and grinding for 35 minutes to obtain a mixed material;

[0042] (2) In an air atmosphere, the mixture was placed in a tube furnace, heated to 1300°C, sintered for 6 h, cooled to room temperature, and ground to obtain Ni 2+ Doped broadband short-wave near-infrared phosphor LiMg2Al9O 16 :0.03Ni 2+ ;

[0043] In this embodiment, Ni 2+ The excitation and emission spectra of the doped broadband short-wave near-infrared phosphors are shown in Figure 3 As shown in the figure, under the ultraviolet light excitation of 370nm, the main emission is 1180nm; under the emission monitoring wavelength of 1180nm, the excitation spectrum is composed of excitation bands located at 370nm and 590nm, which are mainly derived from Ni 2+ of 3 A2(F)- 3 T1(P) and 3 A2(F)- 3 T1(F) energy level transition; in this embodiment Ni 2+ The luminescence intensity of the doped broadband short-wave near-infrared phosphor is stronger than that of Examples 1 and 2, and its half-peak width is 210nm;

[0044] The Ni 2+ Application of doped broadband short-wave near-infrared phosphor in the preparation of SWIR-LED devices; specifically, Ni 2+ Doped broadband short-wave near-infrared phosphor LiMg2Al9O 16 :0.03Ni 2+ Mix with silica gel to obtain phosphor-silica gel mixed solution (Ni in phosphor-silica gel mixed solution) 2+ Doped broadband short-wave near-infrared phosphor LiMg2Al9O 16 :0.03Ni 2+ Then, the phosphor-silica gel mixture is dropped onto a 365nm semiconductor chip and dried at a temperature of 100°C to obtain a SWIR-LED device.

[0045] Embodiment 4: This embodiment Ni 2+ Doped broadband short-wave near-infrared phosphor, chemical formula: LiMg2Al9O 16 :0.04Ni 2+ The phosphor matrix LiMg2Al9O 16 It has a spinel structure;

[0046] A Ni 2+ The preparation method of the doped broadband short-wave near-infrared phosphor comprises the following specific steps:

[0047] (1) weighing raw materials Li2CO3, Mg(OH)2, Al2O3 and Ni(CH3COO)2 according to a stoichiometric ratio and mixing and grinding for 40 minutes to obtain a mixed material;

[0048] (2) In an air atmosphere, the mixture was placed in a tube furnace, heated to 1400°C, sintered for 8 h, cooled to room temperature, and ground to obtain Ni 2+Doped broadband short-wave near-infrared phosphor LiMg2Al9O 16 :0.04Ni 2+ ;

[0049] For LiMg2Al9O 16 :0.04Ni 2+ The phosphor was tested and analyzed by XRD. The results are as follows: Figure 4 As shown in the figure, it can be seen that LiMg2Al9O 16 :0.04Ni 2+ The physical phase of the phosphor can match that of the standard card;

[0050] The FLS-1000 fluorescence spectrophotometer was used to measure the 16 :0.04Ni 2+ The excitation spectrum of the phosphor detected by the 1180nm emission test is as follows Figure 5 As shown in the figure, it can be seen that the main excitation bands are located in the ultraviolet light region (~370nm) and the orange-red light region (~590nm), which indicates that the phosphor can be excited by both ultraviolet light and orange-red light bands at the same time; 2+ With the increase of doping concentration, the transition intensity at 370nm ( 3 A2(F)- 3 T1(P)) gradually increases, while the transition intensity at 590nm ( 3 A2(F)- 3 Although T1(F)) also gradually increases, the increase is not large, indicating that more electrons tend to fill in 3 T1(P) excited state, instead of 3 T1(F);

[0051] The FLS-1000 fluorescence spectrophotometer was used to measure the 16 :0.04Ni 2+ The phosphor was detected under 370nm excitation. Figure 6 As shown in the figure, it can be seen that the phosphor exhibits asymmetric broadband SWIR emission, with the strongest emission peak located at 1180nm;

[0052] Measurement of LiMg2Al9O by FLS-1000 fluorescence spectrophotometer 16 :0.04Ni 2+ Phosphor, LiMg2Al9O 16 :0.04Ni 2+ The decay curve under 370nm excitation is shown in Figure 7 ,As can be seen from the figure, the curve shows a monotonic decay trend, and the fluorescence lifetime is 0.67ns;

[0053] The Ni2+ Application of doped broadband short-wave near-infrared phosphor in the preparation of SWIR-LED devices; specifically, Ni 2+ Doped broadband short-wave near-infrared phosphor LiMg2Al9O 16 :0.04Ni 2+ Mix with silica gel to obtain phosphor-silica gel mixed solution (Ni in phosphor-silica gel mixed solution) 2+ Doped broadband short-wave near-infrared phosphor LiMg2Al9O 16 :0.04Ni 2+ Then, the phosphor-silica gel mixture is dropped onto a 365nm semiconductor chip and dried at 100°C to obtain a SWIR-LED device;

[0054] Venous imaging: Under natural light, humans cannot see the distribution of palm veins with the naked eye. Under the illumination of SWIR-LED light source, the distribution of palm veins can be clearly observed because the near-infrared light source is absorbed by the hemoglobin in the human body (see Figure 8 );

[0055] SWIR-LED devices have excellent luminous properties of small size, portability, and near-infrared coverage, and can be used as near-infrared light sources for night vision imaging under dark conditions. Fig. 9 These are pictures taken under natural light and using a near-infrared camera.

[0056] Embodiment 5: This embodiment Ni 2+ Doped broadband short-wave near-infrared phosphor, chemical formula: LiMg2Al9O 16 :0.05Ni 2+ The phosphor matrix LiMg2Al9O 16 It has a spinel structure;

[0057] A Ni 2+ The preparation method of the doped broadband short-wave near-infrared phosphor comprises the following specific steps:

[0058] (1) weighing raw materials Li2CO3, Mg(OH)2, Al2O3 and Ni(CH3COO)2 according to a stoichiometric ratio and mixing and grinding for 40 minutes to obtain a mixed material;

[0059] (2) In an air atmosphere, the mixture was placed in a tube furnace, heated to 1200°C, sintered for 8 h, cooled to room temperature, and ground to obtain Ni 2+ Doped broadband short-wave near-infrared phosphor LiMg2Al9O 16 :0.05Ni 2+ ;

[0060] In the excitation and emission spectra of the phosphor in the embodiment, the emission at 1180 nm is mainly shown under the ultraviolet light excitation of 370 nm. At the emission monitoring wavelength of 1180 nm, the excitation spectrum is composed of excitation bands at 370 nm and 590 nm, respectively, which are mainly derived from Ni 2+ of 3 A2(F)- 3 T1(P) and 3 A2(F)- 3 T1(F) energy level transition; the half-peak width of the phosphor of Example 5 is 213nm;

[0061] The Ni 2+ Application of doped broadband short-wave near-infrared phosphor in the preparation of SWIR-LED devices; specifically, Ni 2+ Doped broadband short-wave near-infrared phosphor LiMg2Al9O 16 :0.05Ni 2+ Mix with silica gel to obtain phosphor-silica gel mixed solution (Ni in phosphor-silica gel mixed solution) 2+ Doped broadband short-wave near-infrared phosphor LiMg2Al9O 16 :0.05Ni 2+ Then, the phosphor-silica gel mixture is dropped onto a 365nm semiconductor chip and dried at 100°C to obtain a SWIR-LED device.

[0062] The specific implementation modes of the present invention are described in detail above, but the present invention is not limited to the above implementation modes, and various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention.

Claims

1. A Ni 2+ Doped broadband short-wave near-infrared phosphor, characterized by: The general chemical formula is: LiMg2Al9O 16 :xNi 2 + , wherein 0.01≤x≤0.05; the phosphor matrix has a spinel structure, and the phosphor emits short-wave near-infrared light with a peak value of 900-1600nm under the excitation of visible light with a wavelength of 250-750nm, and the half-peak width of the emission spectrum is 200-250nm.

2. Ni according to claim 1 2+ The method for preparing a doped broadband short-wave near-infrared phosphor is characterized in that: The specific steps are as follows: (1) weighing raw materials Li2CO3, Mg(OH)2, Al2O3 and Ni(CH3COO)2 according to a stoichiometric ratio and mixing and grinding to obtain a mixed material; (2) In an air atmosphere, the mixture is heated to a temperature of 1200-1400°C and sintered for 6-8 hours, cooled to room temperature, and ground to obtain Ni 2+ Doped broadband short-wave near-infrared phosphor LiMg2Al9O 16 :xNi 2+ .

3. Ni according to claim 1 2+ Application of doped broadband short-wave near-infrared phosphors in the preparation of SWIR-LED devices.

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