A Ni 2+ Doped broadband short-wave near-infrared fluorescent powder, preparation method and application thereof

Abstract

The application relates to a Ni 2+ The application relates to a kind of doped broadband short wave near infrared fluorescent powder and its preparation method and application, belong to fluorescent material technical field.The Ni 2+ The chemical general formula of the doped broadband short wave near infrared fluorescent powder is: LiMg2Al9O 16 :xNi 2+ , wherein 0.01<=x<=0.05;The fluorescent powder matrix has spinel structure, the fluorescent powder emits peak value in 900-1600nm short wave near infrared light under the excitation of 250-750nm visible light, and the half peak width of emission spectrum is 200-250nm.Due to the spinel structure of LiMg2Al9O 16 , about 3% Mg' Al And Al· Mg Anti-position defect is contained, forms [Mg-O]6 and [Al-O]6 two octahedral sites, can produce the super wide band Ni 2+ Near infrared emission with center wavelength 1180nm and half peak width 210nm under the excitation of 370nm.The fluorescent powder has the advantages of simple synthesis, good thermal stability, low energy consumption, etc., and can solve the problems of poor stability and complex synthesis conditions in the prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of Ni 2+ The application discloses a doped broadband short-wave near-infrared fluorescent powder, a preparation method and application thereof, and belongs to the technical field of fluorescent materials. BACKGROUND

[0002] At present, the short-wave infrared (SWIR) light sources commonly used in the field of spectral analysis include incandescent halogen lamps, lasers and LEDs, however, each of them has specific advantages and disadvantages. The halogen lamp can produce continuous spectral radiation from visible light to infrared light, but its significant disadvantages include large size, short service life, low energy efficiency and high-temperature safety hazards. In contrast, the laser diode or fiber laser has high radiation intensity, but its high-coherence laser beam and narrow emission spectrum limit its practicability in industrial applications. In addition, the supercontinuum laser is not suitable for wide application due to its small divergence angle, high power consumption and relatively high cost. The SWIR-LED chip gradually becomes a new generation of NIR solid-state light source due to its small size, high efficiency and long service life. However, the relatively narrow spectral coverage (<50 nm), low output power and high cost limit its application in the SWIR field. SUMMARY

[0003] In view of the problems of the existing SWIR-LED chip, such as relatively narrow spectral coverage (<50 nm), low output power and high cost, the present application provides a kind of Ni 2+ The application discloses a doped broadband short-wave near-infrared fluorescent powder, a preparation method and application thereof, and belongs to the technical field of fluorescent materials. 16 The application discloses a doped broadband short-wave near-infrared fluorescent powder, a preparation method and application thereof, and belongs to the technical field of fluorescent materials. 2+ The doping of Ni Al and Al· Mg anti-site defects in the spinel structure forms two octahedral sites of [Mg-O]6 and [Al-O]6, and the oxidation state of nickel ions is very stable, which exhibits excellent luminescent performance in octahedral coordination and a wide near-infrared emission band. 2+ The fluorescent powder 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 prior art.

[0004] The application discloses a doped broadband short-wave near-infrared fluorescent powder, a preparation method and application thereof, and belongs to the technical field of fluorescent materials. 2+ The application discloses a doped broadband short-wave near-infrared fluorescent powder, a preparation method and application thereof, and belongs to the technical field of fluorescent materials. 16 The application discloses a doped broadband short-wave near-infrared fluorescent powder, a preparation method and application thereof, and belongs to the technical field of fluorescent materials. 2+Where 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 when excited by visible light with a wavelength of 250-750nm, and the half-width of the emission spectrum is 200-250nm.

[0005] The Ni 2+ The preparation method of doped broadband short-wavelength near-infrared phosphors includes the following specific steps:

[0006] (1) Weigh and grind the raw materials Li2CO3, Mg(OH)2, Al2O3 and Ni(CH3COO)2 according to the stoichiometric ratio to obtain a mixture;

[0007] (2) Under air atmosphere, the mixture is heated to 1200-1400℃ and sintered for 6-8 hours, then cooled to room temperature and ground to obtain Ni. 2+ Doped broadband short-wavelength near-infrared phosphor LiMg2Al9O 16 :xNi 2+ .

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

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

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

[0011] The spinel structure matrix of this invention is LiMg2Al9O 16 Ni has high chemical, thermal and optical stability. 2+ Belongs to 3D 8 Electronic structure, coordinating with oxygen to form octahedral and tetrahedral structures, in spinel matrix, Ni 2+ and B 3+ With similar ionic radii, Ni 2+ It is easy to replace B 3+Enter the octahedral site, so as to realize the required SWIR emission; Single cation Ni 2+ Substitution to adjust the crystal field strength, reduce the non-radiative transition probability, thereby improving the luminous efficiency and thermal stability.

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

[0013] (1) The broadband short-wave near-infrared fluorescent powder of the present application is an oxide with spinel structure, multiple lattice sites, and large spectral coverage range, and has stable physical and chemical properties, simple preparation method, and short reaction time.

[0014] (2) The near-infrared fluorescent powder of the present application can produce a broadband near-infrared emission peak under 370nm excitation, with the emission peak located in the wavelength range of 900-1600nm, and the half-width of 210nm, and the strongest emission peak located at 1180nm, having the advantages of wide excitation range and wide emission peak spectrum.

[0015] (3) The excellent photoelectric performance of the near-infrared fluorescent powder of the present application makes the prepared pc-NIR LED show good penetration and night vision imaging, and can be used for vein imaging or night vision imaging. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 LiMg2Al9O 16 : 0.01Ni 2+ Excitation and emission spectra of the fluorescent powder;

[0017] Figure 2 LiMg2Al9O 16 : 0.02Ni 2+ Excitation and emission spectra of the fluorescent powder;

[0018] Figure 3 LiMg2Al9O 16 : 0.03Ni 2+ Excitation and emission spectra of the fluorescent powder;

[0019] Figure 4 LiMg2Al9O 16 : 0.04Ni 2+ XRD pattern and standard card of the fluorescent powder;

[0020] Figure 5 LiMg2Al9O 16 : 0.04Ni 2+ Excitation spectrum in the fluorescent powder;

[0021] Figure 6 LiMg2Al9O16 : 0.04Ni 2+ emission spectrum diagram;

[0022] Figure 7 LiMg2Al9O 16 : 0.04Ni 2+ decay curve under 370nm excitation;

[0023] Figure 8 LiMg2Al9O 16 : 0.04Ni 2+ application results in intravenous imaging;

[0024] Figure 9 LiMg2Al9O 16 : 0.04Ni 2+ application results in night vision imaging; DETAILED DESCRIPTION

[0025] The application will be further described in conjunction with the specific embodiments, but the scope of protection of the application is not limited to the described content.

[0026] Example 1: In this example, Ni 2+ doped broadband short-wave near-infrared fluorescent powder, chemical formula: LiMg2Al9O 16 : 0.01Ni 2+ , the fluorescent powder matrix LiMg2Al9O 16 has a spinel structure;

[0027] A preparation method of Ni 2+ doped broadband short-wave near-infrared fluorescent powder, the specific steps are as follows:

[0028] (1) The raw materials Li2CO3, Mg(OH)2, Al2O3 and Ni(CH3COO)2 are weighed and mixed and ground for 30min to obtain a mixture;

[0029] (2) Under an air atmosphere, the mixture is placed in a tube furnace and heated to a temperature of 1200℃ for sintering for 8h, cooled to room temperature, and ground to obtain Ni 2+ doped broadband short-wave near-infrared fluorescent powder LiMg2Al9O 16 : 0.01Ni 2+ ;

[0030] In this example, Ni 2+ doped broadband short-wave near-infrared fluorescent powder has an excitation and emission spectrum as shown in Figure 1The emission spectrum is mainly composed of excitation bands at 370nm and 590nm, mainly originating from Ni 2+ 3 A2(F)- 3 T1(P) and 3 A2(F)- 3 T1(F) energy level transition; the half-peak width of the phosphor of the embodiment is 209nm;

[0031] The Ni 2+ doped broadband short-wave near-infrared fluorescent powder is applied in the preparation of a SWIR-LED device; specifically, the Ni 2+ doped broadband short-wave near-infrared fluorescent powder LiMg2Al9O 16 :0.01Ni 2+ is mixed with silica gel to obtain a fluorescent powder-silica gel mixed solution (the content of the Ni 2+ doped broadband short-wave near-infrared fluorescent powder LiMg2Al9O 16 :xNi 2+ is 45wt.%), then the fluorescent powder-silica gel mixed solution is dropped onto a 365nm semiconductor chip, and the SWIR-LED device is obtained after drying at a temperature of 100℃.

[0032] The Ni 2+ doped broadband short-wave near-infrared fluorescent powder of the embodiment has a chemical formula of LiMg2Al9O 16 :0.02Ni 2+ ; the fluorescent powder matrix LiMg2Al9O 16 has a spinel structure;

[0033] A method for preparing a Ni 2+ doped broadband short-wave near-infrared fluorescent powder, and the specific steps are as follows:

[0034] (1) raw materials Li2CO3, Mg(OH)2, Al2O3 and Ni(CH3COO)2 are weighed and mixed and ground for 35min to obtain a mixture;

[0035] (2) the mixture is placed in a tube furnace under an air atmosphere, heated to a temperature of 1250℃ and sintered for 7h, cooled to room temperature, and ground to obtain a Ni 2+ doped broadband short-wave near-infrared fluorescent powder LiMg2Al9O 16 :0.02Ni 2+ ;

[0036] The Ni 2+ ​Excitation and emission spectra of doped broadband short-wavelength near-infrared phosphors, such as Figure 2 As shown, under 370 nm ultraviolet light excitation, the main emission is at 1180 nm; at the emission monitoring wavelength of 1180 nm, the excitation spectrum consists of excitation bands located at 370 nm and 590 nm, mainly originating from Ni. 2+ of 3 A2(F)- 3 T1(P) and 3 A2(F)- 3 T1(F) energy level transition; the full width at half maximum (FWHM) of the phosphor in this embodiment is 209 nm;

[0037] The Ni 2+ Application of doped broadband short-wavelength near-infrared phosphors in the fabrication of SWIR-LED devices; specifically, Ni 2+ Doped broadband short-wavelength near-infrared phosphor LiMg2Al9O 16 0.02Ni 2+ The phosphor-silica mixture is thoroughly mixed with silica gel to obtain a phosphor-silica gel solution (Ni in the phosphor-silica gel solution) 2+ Doped broadband short-wavelength near-infrared phosphor LiMg2Al9O 16 0.02Ni 2+ The phosphor-silica mixture is prepared by dropping the phosphor-silica mixture onto a 365nm semiconductor chip and drying it at 100°C to obtain the SWIR-LED device.

[0038] Example 3: In this example, Ni 2+ Doped broadband short-wave near-infrared phosphor, with the chemical formula: LiMg2Al9O 16 0.03Ni 2+ The phosphor matrix LiMg2Al9O 16 It has a spinel structure;

[0039] A Ni 2+ The preparation method of doped broadband short-wavelength near-infrared phosphors includes the following specific steps:

[0040] (1) Weigh the raw materials Li2CO3, Mg(OH)2, Al2O3 and Ni(CH3COO)2 according to the stoichiometric ratio and mix and grind them for 35 min to obtain a mixture;

[0041] (2) Under air atmosphere, the mixture was placed in a tube furnace, heated to 1300℃ and sintered for 6 hours, cooled to room temperature, and then ground to obtain Ni. 2+ Doped broadband short-wavelength near-infrared phosphor LiMg2Al9O 16 0.03Ni 2+ ;

[0042] The Ni 2+ doped broadband short-wave near-infrared fluorescent powder of the embodiment Figure 3 exhibits mainly 1180nm emission under 370nm ultraviolet excitation; under 1180nm emission monitoring wavelength, the excitation spectrum is composed of excitation bands at 370nm and 590nm, mainly originating from Ni 2+ doped broadband short-wave near-infrared fluorescent powder 3 A2(F)- 3 T1(P) and 3 A2(F)- 3 T1(F) energy level transitions; the Ni 2+ doped broadband short-wave near-infrared fluorescent powder of the embodiment has a stronger luminescence intensity than that of embodiments 1 and 2, and has a half-peak width of 210nm;

[0043] The Ni 2+ doped broadband short-wave near-infrared fluorescent powder is applied in the preparation of a SWIR-LED device; specifically, the Ni 2+ doped broadband short-wave near-infrared fluorescent powder LiMg2Al9O 16 :0.03Ni 2+ is mixed with silica gel to obtain a fluorescent powder-silica gel mixture (the content of the Ni 2+ doped broadband short-wave near-infrared fluorescent powder LiMg2Al9O 16 :0.03Ni 2+ is 55wt.%), then the fluorescent powder-silica gel mixture is dropped onto a 365nm semiconductor chip, and dried at a temperature of 100℃ to obtain a SWIR-LED device.

[0044] The Ni 2+ doped broadband short-wave near-infrared fluorescent powder of the embodiment has a chemical formula of LiMg2Al9O 16 :0.04Ni 2+ , and the fluorescent powder matrix LiMg2Al9O 16 has a spinel structure;

[0045] A preparation method of a Ni 2+ doped broadband short-wave near-infrared fluorescent powder, and the specific steps are as follows:

[0046] (1) raw materials Li2CO3, Mg(OH)2, Al2O3 and Ni(CH3COO)2 are weighed and mixed and ground for 40min to obtain a mixture;

[0047] (2) under an air atmosphere, the mixture is placed in a tube furnace, heated to a temperature of 1400℃ and sintered for 8h, cooled to room temperature, and ground to obtain a Ni 2+Doped broadband short-wavelength near-infrared phosphor LiMg2Al9O 16 0.04Ni 2+ ;

[0048] For LiMg2Al9O 16 0.04Ni 2+ The phosphor was analyzed by XRD, and the results are as follows: Figure 4 As shown in the figure, LiMg2Al9O 16 0.04Ni 2+ The phase of the phosphor can be matched with the standard card;

[0049] LiMg2Al9O was measured using an FLS-1000 fluorescence spectrophotometer. 16 0.04Ni 2+ The excitation spectrum of the phosphor detected at 1180 nm emission test is as follows: Figure 5 As shown in the figure, the main excitation bands are located in the ultraviolet region (~370 nm) and the orange-red region (~590 nm), indicating that the phosphor can be excited by both ultraviolet and orange-red light bands simultaneously; with Ni 2+ With increasing doping concentration, the transition intensity at 370 nm ( 3 A2(F)- 3 T1(P) gradually increases, while the transition intensity at 590 nm ( 3 A2(F)- 3 Although T1(F) also gradually increases, the increase is not significant, indicating that more electrons tend to fill the space. 3 At the T1(P) excited state, rather than 3 T1(F);

[0050] LiMg2Al9O was measured using an FLS-1000 fluorescence spectrophotometer. 16 0.04Ni 2+ The phosphor, when excited at 370 nm, showed the following results: Figure 6 As shown in the figure, the phosphor exhibits asymmetric broadband SWIR emission, with the strongest emission peak located at 1180 nm.

[0051] LiMg2Al9O was measured using an FLS-1000 fluorescence spectrophotometer. 16 0.04Ni 2+ Phosphor, LiMg2Al9O 16 0.04Ni 2+ The attenuation curve under 370nm excitation is shown below. Figure 7 As can be seen from the figure, the curve shows a monotonically decreasing trend, and the fluorescence lifetime is 0.67 ns;

[0052] The Ni2+ The application of the doped broadband short-wave near-infrared fluorescent powder in the preparation of a SWIR-LED device; specifically, Ni 2+ The application of the doped broadband short-wave near-infrared fluorescent powder LiMg2Al9O 16 :0.04Ni 2+ The fluorescent powder-silica gel mixture was obtained by fully mixing the fluorescent powder and the silica gel (the content of the fluorescent powder in the fluorescent powder-silica gel mixture was 50 wt.%), then, the fluorescent powder-silica gel mixture was dropped onto a 365 nm semiconductor chip, and the SWIR-LED device was obtained by drying at a temperature of 100℃; 2+ The application of the doped broadband short-wave near-infrared fluorescent powder LiMg2Al9O 16 :0.04Ni 2+ The content of the fluorescent powder in the fluorescent powder-silica gel mixture was 50 wt.%), then, the fluorescent powder-silica gel mixture was dropped onto a 365 nm semiconductor chip, and the SWIR-LED device was obtained by drying at a temperature of 100℃;

[0053] Imaging of veins: under natural light, the vein distribution of a human palm cannot be observed by naked eyes, but under the irradiation of the SWIR-LED light source, the vein distribution of the palm can be clearly observed due to the absorption of near-infrared light by hemoglobin in the human body (see Figure 8 );

[0054] The SWIR-LED device has excellent light-emitting characteristics such as small size, portability, and near-infrared coverage range, and can be used as a near-infrared light source for night vision imaging in dark conditions, Figure 9 respectively, a picture taken under natural light and a picture taken by using a near-infrared camera.

[0055] Example 5: In this example, Ni 2+ The application of the doped broadband short-wave near-infrared fluorescent powder, LiMg2Al9O 16 :0.05Ni 2+ The fluorescent powder matrix LiMg2Al9O 16 has a spinel structure;

[0056] A method for preparing a Ni 2+ doped broadband short-wave near-infrared fluorescent powder, and the specific steps are as follows:

[0057] (1) The raw materials Li2CO3, Mg(OH)2, Al2O3 and Ni(CH3COO)2 were weighed and mixed and ground for 40 min to obtain a mixture;

[0058] (2) The mixture was placed in a tube furnace under an air atmosphere, heated to a temperature of 1200℃, sintered for 8h, cooled to room temperature, and ground to obtain a Ni 2+ doped broadband short-wave near-infrared fluorescent powder LiMg2Al9O 16 :0.05Ni 2+ ;

[0059] The phosphor powder of the embodiment mainly shows emission at 1180 nm under the excitation of ultraviolet light at 370 nm. Under the monitoring wavelength of 1180 nm emission, the excitation spectrum is composed of excitation bands at 370 nm and 590 nm, mainly originating from Ni 2+ doped 3 A2(F)- 3 T1(P) and 3 A2(F)- 3 T1(F) energy level transition; the half-peak width of the phosphor powder of embodiment 5 is 213 nm;

[0060] The Ni 2+ doped broadband short-wave near-infrared phosphor powder is applied in the preparation of a SWIR-LED device. Specifically, the Ni 2+ doped broadband short-wave near-infrared phosphor powder LiMg2Al9O 16 :0.05Ni 2+ is mixed with silica gel to obtain a phosphor-silica gel mixture (the content of the Ni 2+ doped broadband short-wave near-infrared phosphor powder LiMg2Al9O 16 :0.05Ni 2+ is 50 wt.%, then the phosphor-silica gel mixture is dropped onto a 365 nm semiconductor chip, and dried at a temperature of 100℃ to obtain a SWIR-LED device.

[0061] The specific embodiments of the present application are described in detail above, but the present application is not limited to the above-described embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the spirit of the present application.

Claims

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

2. The Ni of claim 1 2+ The preparation method of the doped broadband short-wave near-infrared fluorescent powder is characterized by comprising the following steps: The specific steps are as follows: (1) the raw materials Li2CO3, Mg(OH)2, Al2O3 and Ni(CH3COO)2 are weighed and mixed and ground according to the stoichiometric ratio to obtain a mixture; (2) under air atmosphere, the mixture is heated to a temperature of 1200-1400℃ for sintering for 6-8h, cooled to room temperature, and grinded to obtain Ni 2+ Doped broadband short-wave near-infrared fluorescent powder LiMg2Al9O 16 : xNi 2+ .

3. The Ni of claim 1 2+ Use of doped broadband short-wave near-infrared fluorescent powder in the preparation of SWIR-LED devices.

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