CN111073645B

CN111073645B - Broadband fluorescent powder, preparation method thereof, application of broadband fluorescent powder and light-emitting device

Info

Publication number: CN111073645B
Application number: CN201911384034.4A
Authority: CN
Inventors: 张亮亮; 孙大帅; 张家骅; 杨霖; 张霞; 潘国徽; 吴昊; 武华君
Original assignee: Changchun Institute of Optics Fine Mechanics and Physics of CAS
Current assignee: Changchun Institute of Optics Fine Mechanics and Physics of CAS
Priority date: 2019-12-28
Filing date: 2019-12-28
Publication date: 2021-03-19
Anticipated expiration: 2039-12-28
Also published as: CN111073645A

Abstract

The chemical formula of the broadband fluorescent powder provided by the invention is as follows: r_6‑a‑ _bCe_aPr_bSi₁₂N_22‑4eC_3eWherein R is selected from Lu³⁺And Y³⁺One or two of the above, Ce is Ce³⁺Pr is Pr³⁺Si is Si⁴⁺N is N^3‑C is C^4‑A, b and e are mole fractions, a is more than or equal to 0 and less than or equal to 0.6 in the value range of a, b is more than or equal to 0.0006 and less than or equal to 0.12 in the value range of b, and e is more than or equal to 0 and less than or equal to 1 in the value range of e³⁺After being excited, the ions can realize broadband blue-green light and red light emission, and the full width at half maximum is respectively as high as about 25nm and 37 nm. Codoped Pr³⁺And Ce³⁺After ions are ionized, continuous adjustable emission from 490nm to 650nm can be realized, the full width at half maximum reaches about 155nm, and the red fluorescent material is used as an independent luminous center, namely Pr³⁺And Ce³⁺The reabsorption between the two is weak, which is beneficial to the spectral broadening and the color rendering property improvement, and because of Lu³⁺Has an ionic radius of less than Y³⁺The ion radius of Lu can be changed according to the requirement³⁺And Y³⁺The ratio of the light source to the light source is adjusted, and the light source has great application potential in the fields of white light illumination and the like.

Description

Broadband fluorescent powder, preparation method thereof, application of broadband fluorescent powder and light-emitting device

Technical Field

The invention relates to the technical field of fluorescent materials, in particular to broadband fluorescent powder, a preparation method thereof and application thereof to a light-emitting device.

Background

In recent years, semiconductor lighting and laser lighting have attracted great attention as a new generation of light source, and compared with traditional incandescent lamps and fluorescent lamps, the two lighting sources have the advantages of durability, no pollution, stable performance, high efficiency and the like. The mainstream scheme of white light illumination at present adopts a fluorescent powder conversion technology, and the most mature approach is that an InGaN blue Light Emitting Diode (LED) chip and a garnet structure (YAG: Ce)³⁺) The yellow fluorescent powder forms a white light LED, the fluorescent powder is a key factor for determining the performances of the white light LED such as color rendering index, color temperature and the like, but the white light LED has low color rendering index (Ra) due to lack of blue-green light and red light<80) High color temperature (CCT)>5000K) The application field of white light LEDs is limited. The luminous intensity of the blue light spectrum of the InGaN blue light chip is increased faster than that of yellow light under high current, so that the problems of color drift and color temperature change of the white light LED are caused, and meanwhile, the high-intensity blue light can stimulate eyes of people and cause certain harm to the eyes of the people.

In addition, the other white light illumination scheme is fluorescent powder effectively excited by the ultraviolet chip and the ultraviolet chip, and because human eyes are not sensitive to ultraviolet light, white light obtained by the scheme is only related to the light emission of the fluorescent powder, so that the white light illumination scheme has the advantages of stable color, strong reproducibility and the like, and is the development direction of white light illumination.

With the rise of the domestic culture industry in recent years, the market demand in the field of high-end illumination is further expanded, and higher requirements are put forward on the quality of light sources in high-grade hotels, museums, hospitals, schools and the like. Therefore, the search for the fluorescent powder capable of emitting blue-green light and red light in a broadband under the excitation of ultraviolet light is greatly beneficial to seizing the high-end lighting market.

Rare earth Pr³⁺Can emit blue-green light and red light after being excited, but most of researches and reports on Pr³⁺The emission is narrow, and the narrow emission band does not greatly contribute to the color rendering index and the color temperature of the white light LED, for example, in 2017, the inventor of rare earth new materials and the national rare earth new materials company have jointly disclosed a nitride luminescent material (application publication No. CN 107974252A), the chemical formula of which is M_mA_bX_yD_zAnd La₃Si₆N₁₁Has the same crystal structure and belongs to a tetragonal system, Pr³ ⁺The matrix emits narrow-band light, and has a full width at half maximum of an emission peak in a blue-green region of only about 7nm and a full width at half maximum of an emission peak in a red region of only about 10nm, which is not favorable for white light illumination.

Disclosure of Invention

Therefore, it is necessary to provide a broadband phosphor capable of solving the problem of lacking broadband blue-green light and red light in ultraviolet LED illumination, aiming at the defects existing in the prior art.

In order to achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the present invention provides a broadband phosphor, wherein the phosphor has a chemical formula: r_6-a- _bCe_aPr_bSi₁₂N_22-4eC_3eWherein R is selected from Lu³⁺And Y³⁺One or two of the above, Ce is Ce³⁺Pr is Pr³⁺Si is Si⁴⁺N is N^3-C is C^4-A, b and e are mole fractions, a is more than or equal to 0 and less than or equal to 0.6 in the value range of a, b is more than or equal to 0.0006 and less than or equal to 0.12 in the value range of b, and e is more than or equal to 0 and less than or equal to 1 in the value range of e.

The broadband phosphor material belongs to a monoclinic system space group P2₁C, and Ho₂Si₄N₆C has the same crystal structure consisting of [ SiN ]₄]Or [ SiCN ]₃]Tetrahedral and built with angle-angle links, with [ N (SiN) present in the structure₃)₄]Or [ C (SiN)₃)₄]Star-like structure enabling Pr³⁺The 4f energy level of the optical fiber is severely split, so that broadband emission is realized.

When a is 0, the broadband is singly doped with Pr³⁺When in use, the peak wavelength of the excitation spectrum of the broadband fluorescent powder is positioned in the area of 280 nm-380 nm, the emission bands are positioned in the areas of 490nm-520nm and 610nm-650nm, the full widths at half maximum are respectively as high as about 25nm and 37nm, namely Pr³⁺After the ions are excited, broadband blue-green light and red light emission can be realized.

Broadband when 0<When a is less than or equal to 0.6, the Pr is codoped³⁺And Ce³⁺After ion, continuous adjustable emission can be realized from 490nm to 650nm, the full width at half maximum reaches about 155nm, and the red fluorescent material is used as an independent luminescent center, namely Pr³⁺And Ce³⁺The reabsorption between the two is weak, which is beneficial to the spectral broadening and the color rendering property improvement, and because of Lu³⁺Has an ionic radius of less than Y³⁺The ion radius of Lu can be changed according to the requirement³⁺And Y³⁺The ratio of the light source to the light source is adjusted, and the light source has great application potential in the fields of white light illumination and the like.

It can be understood that the broadband fluorescent powder provided by the invention has the characteristic that the luminescent center is Pr³⁺When in ion, the broadband emission in the 490-520 nm and 610-650 nm regions can be realized, and the luminescence center Ce is further introduced³⁺Ion through Pr³⁺And Ce³⁺The co-doping can realize continuous adjustable emission from 490nm to 650nm, and is an excellent broadband luminescent material.

In a second aspect, the present invention further provides a method for preparing a broadband phosphor, comprising the following steps:

step S110: according to the formula R_6-a-bCe_aPr_bSi₁₂N_22-4eC_3eThe stoichiometric ratio of each element in the composition is measured to contain Y³⁺Compound of (1) and composition containing Lu³⁺Compound of (2) and containing Ce³⁺Compound of (1), containing Pr³⁺Compound of (1), containing Si⁴⁺Grinding and uniformly mixing the compound (A) and the carbon simple substance or the organic substance containing the carbon element to obtain a mixture;

step S120: and heating the mixture in a nitrogen atmosphere to a sintering temperature of 1500-1700 ℃, wherein the sintering time is 4-10 h, taking out a sample after the furnace body is cooled, and grinding, washing, sieving and drying the sample to obtain the broadband fluorescent powder.

Said compound containing Y³⁺The compound of (A) is a compound containing Y³⁺One or more of oxides, nitrides and nitrates of ions; the content of Lu³⁺The compound of (A) is Lu-containing³⁺One or more of oxides, nitrides and nitrates of (a);said containing Ce³ ⁺The compound of (A) is Ce-containing³⁺One or more of oxides, nitrides and nitrates of (a); the component containing Pr³⁺The compound of (A) is a compound containing Pr³⁺One or more of oxides, nitrides, nitrates and fluorides of (a); said Si-containing compound⁴⁺The compound of (A) is Si-containing⁴⁺One or more of oxides, nitrides and carbides of (a).

The broadband phosphor material belongs to a monoclinic system space group P2₁C, and Ho₂Si₄N₆C has a similar crystal structure consisting of [ SiN ]₄]Or [ SiCN ]₃]Tetrahedral and built with angle-angle links, with [ N (SiN) present in the structure₃)₄]Or [ C (SiN)₃)₄]Star-like structure enabling Pr³⁺The 4f energy level of the optical fiber is severely split, so that broadband emission is realized.

In a third aspect, the invention further provides an application of the broadband fluorescent powder, and the broadband fluorescent powder is used as a light conversion material and applied to a light-emitting device.

In a fourth aspect, the present invention also provides a method for manufacturing a light emitting device, including the steps of:

step S110: mixing the broadband fluorescent powder with a binder to obtain slurry;

step S120: coating the slurry on an excitation light source chip, and curing to obtain the light-emitting device;

the chemical formula of the fluorescent powder is as follows: r_6-a-bCe_aPr_bSi₁₂N_22-4eC_3eWherein R is selected from Lu³⁺And Y³⁺One or two of the above, Ce is Ce³⁺Pr is Pr³⁺Si is Si⁴⁺N is N^3-C is C^4-A, b and e are mole fractions, a is more than or equal to 0 and less than or equal to 0.6 in the value range of a, b is more than or equal to 0.0006 and less than or equal to 0.12 in the value range of b, and e is more than or equal to 0 and less than or equal to 1 in the value range of e.

The adhesive is generally an epoxy resin or a silica gel material, generally classified as A, B glue, A, B glue is mixed according to a certain proportion to be used as an adhesive for packaging, and the curing modes of the adhesive include but are not limited to different curing modes such as normal temperature curing, high temperature curing, photocuring and the like.

The exciting light source chip is a 280 nm-380 nm ultraviolet LED light source chip or a laser light source chip.

The invention adopts the technical scheme that the method has the advantages that:

the chemical formula of the broadband fluorescent powder provided by the invention is as follows: r_6-a-bCe_aPr_bSi₁₂N_22-4eC_3eWherein R is selected from Lu³⁺And Y³⁺One or two of the above, Ce is Ce³⁺Pr is Pr³⁺Si is Si⁴⁺N is N^3-C is C^4-A, b and e are mole fractions, a is more than or equal to 0 and less than or equal to 0.6 in the value range of a, b is more than or equal to 0.0006 and less than or equal to 0.12 in the value range of b, and e is more than or equal to 0 and less than or equal to 1 in the value range of e³⁺The ions can realize broadband blue-green light and red light emission after being excited, the full width at half maximum is respectively up to about 25nm and 37nm, and the ions are codoped with Pr³⁺And Ce³⁺After ions are ionized, continuous adjustable emission from 490nm to 650nm can be realized, the full width at half maximum reaches about 155nm, and the red fluorescent material is used as an independent luminous center, namely Pr³⁺And Ce³⁺The reabsorption between the two is weak, which is beneficial to the spectral broadening and the color rendering property improvement, and because of Lu³⁺Has an ionic radius of less than Y³⁺The ion radius of Lu can be changed according to the requirement³⁺And Y³⁺The ratio of the light source to the light source is adjusted, and the light source has great application potential in the fields of white light illumination and the like.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 shows the broad band phosphor of the present invention, examples 1 and 7XRD spectrum and Ho₂Si₄N₆C Standard cards ICSD #162420 and La₃Si₆N₁₁PDF # 48-4805.

FIG. 2 shows the emission spectrum of example 1 of the broad band phosphor of the present invention.

FIG. 3 shows the emission spectrum of example 7 of the broad band phosphor of the present invention.

Fig. 4 is a graph of the electroluminescence spectrum of an encapsulated LED of comparative example 2.

Fig. 5 is a graph of the electroluminescence spectrum of an encapsulated LED of example 7 of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The preparation method of the broadband fluorescent powder provided by the invention is a high-temperature solid phase method. However, the synthesis method of the phosphor is not limited thereto. Wherein, the fluorescent powder can be synthesized by wet chemical methods such as a sol-gel method, a combustion method, an emulsion method and the like.

Comparative example 1

La_2.91Si₆N₁₁:Pr_0.09The preparation of (1) LaN, CeN, Si are respectively weighed according to the stoichiometric ratio₃N₄And uniformly mixing the PrN powder in a mortar, and carrying out heat preservation for 3 hours at 1600 ℃ in a reducing atmosphere, crushing, washing with water to remove impurities, sieving and drying the obtained product to obtain the fluorescent powder of the comparative example 1. XRD spectra of the sample of comparative example 1 and La in FIG. 1₃Si₆N₁₁The standard card PDF #48-4805 is the same.

Comparative example 2

Lu_2.88Y_2.88Ce_0.24Si₁₂N₂₀C_1.5The preparation method comprises the steps of weighing raw materials according to the stoichiometric ratio, grinding the raw materials uniformly in an agate mortar, and then filling the raw materials into a cruciblePlacing the crucible in a tube furnace, roasting at 1700 ℃ for 6 hours at the heating rate of 3 ℃/min in the nitrogen atmosphere, taking out a sample after the furnace body is cooled, and grinding, washing, sieving and drying to obtain the fluorescent powder of the comparative example 2. The fluorescent powder of the comparative example 2 is used for preparing an LED luminescent device according to the following steps, firstly, epoxy resin A, B glue is added according to the volume ratio of 1: 1, then mixing the fluorescent powder of the comparative example 2 with the mixed epoxy resin adhesive according to the mass ratio of 1: 1, uniformly mixing to obtain slurry, finally coating the uniformly mixed slurry on a 310nm ultraviolet LED chip, and curing at 120 ℃ for 20 minutes to obtain the light-emitting device, wherein a packaged LED electroluminescence spectrogram of the comparative example 2 is shown in a figure 4.

Example 1

Lu_2.976Y_2.976Pr_0.048Si₁₂N₂₀C_1.5The preparation of the fluorescent powder comprises the steps of weighing raw materials according to a stoichiometric ratio, uniformly grinding the raw materials in an agate mortar, putting the raw materials into a crucible, putting the crucible into a tube furnace, roasting the crucible for 6 hours at 1700 ℃ at the heating rate of 3 ℃/min in the nitrogen atmosphere, taking out a sample after the furnace body is cooled, and grinding, washing, sieving and drying the sample to obtain the fluorescent powder in the embodiment 1.

The XRD pattern of the sample prepared in example 1 is shown in FIG. 1, while Ho₂Si₄N₆C and La₃Si₆N₁₁By comparison, the phosphor provided by the invention can be found to be the same as Ho₂Si₄N₆C is in agreement with La₃Si₆N₁₁Different. The emission spectrum of this example 1 is shown in FIG. 2, and it can be seen that the phosphor Pr of the comparative example 1 is different from that which has been reported previously³⁺In La₃Si₆N₁₁The phosphor of this example 1 has very broad emission in the 490nm to 520nm and 610nm to 650nm regions.

Examples 2 to 6 have a synthesis method similar to that of example 1, and the chemical formulae, synthesis temperature, firing time, and light-emitting region are shown in attached table 1. In examples 2-6, the emission spectra are similar to those of FIG. 2.

TABLE 1 attached chemical formulas, synthesis temperatures, firing times and light emitting areas of examples 2-6

Examples	Chemical formula (II)	Synthesis temperature	Time of calcination	Light emitting area
					2	Y_5.928Pr_0.072Si₁₂N₂₀C_1.5	1700℃	10h	490nm-520nm and 610nm-650nm
3	Lu_5.88Pr_0.12Si₁₂N₂₀C_1.5	1600℃	4h	490nm-520nm and 610nm-650nm
					4	Lu_1.976Y₄Pr_0.024Si₁₂N_19.2C_2.1	1700℃	8h	490nm-520nm and 610nm-650nm
5	Lu_2.9997Y_2.9997Pr_0.0006Si₁₂N₁₈C₃	1700℃	6h	490nm-520nm and 610nm-650nm
					6	Lu₄Y_1.988Pr_0.012Si₁₂N₂₂	1500℃	10h	490nm-520nm and 610nm-650nm

Example 7

Lu_2.856Y_2.856Pr_0.048Ce_0.24Si₁₂N₂₀C_1.5The preparation of (1) is that the raw materials are weighed according to the stoichiometric ratio, and are uniformly ground in an agate mortar, then the mixture is put into a crucible and put into a tube furnace, the temperature rise speed is 3 ℃/min in the nitrogen atmosphere, the mixture is roasted for 6 hours at 1700 ℃, after the furnace body is cooled, a sample is taken out, and then the sample is ground, washed, sieved and dried, thus obtaining the fluorescent powder of the example 7.

The XRD pattern of the sample prepared in this example 7 is shown in FIG. 1, while Ho₂Si₄N₆C and La₃Si₆N₁₁By comparison, the phosphor provided by the invention can be found to be the same as Ho₂Si₄N₆C is in agreement with La₃Si₆N₁₁Different. The emission spectrum of this example 7 is shown in fig. 3, and it can be seen that the phosphor of this example 7 realizes a broad-band emission from 490nm to 650nm, and this ultra-wide emission band is advantageous in the field of white light illumination.

An LED light emitting device was prepared by using the broadband phosphor of this example 7 according to the following steps, first, epoxy A, B glue was added in a volume ratio of 1: 1, then mixing the broadband phosphor of this embodiment 7 with the mixed epoxy resin glue according to a mass ratio of 1: 1, uniformly mixing to obtain slurry, finally coating the uniformly mixed slurry on a 310nm ultraviolet LED chip, and curing at 120 ℃ for 20 minutes to obtain the light-emitting device. The electroluminescence spectrum of the packaged LED of the example 7 is shown in FIG. 5, and compared with the phosphor-packaged LED of the comparative example 2, the color rendering index is obviously improved from 76.9 to 96.4, and the color temperature is also obviously reduced from 5663K to 4559K. The white light LED with high color rendering index and low color temperature is obtained.

Examples 8 to 12 have a synthesis method similar to that of example 7, and the chemical formulae, synthesis temperature, firing time, and light-emitting region are shown in attached Table 2. In examples 8 to 12, the emission spectra were similar to those of FIG. 3.

TABLE 2 attached chemical formulas, synthesis temperatures, firing times and light emitting areas of examples 8-12

Examples	Chemical formula (II)	Synthesis temperature	Time of calcination	Light emitting area
					8	Y_5.448Pr_0.072Ce_0.48Si₁₂N₂₀C_1.5	1700℃	10h	490nm-650nm
9	Lu_5.28Pr_0.12Ce_0.6Si₁₂N₂₀C_1.5	1600℃	4h	490nm-650nm
					10	Lu_1.916Y₄Pr_0.024Ce_0.06Si₁₂N_19.2C_2.1	1700℃	8h	490nm-650nm
11	Lu_2.8797Y_2.8797Pr_0.0006Ce_0.24Si₁₂N₁₈C₃	1700℃	6h	490nm-650nm
					12	Lu₄Y_1.628Pr_0.012Ce_0.36Si₁₂N₂₂	1500℃	10h	490nm-650nm

Of course, the broad band phosphor of the present invention can have various changes and modifications, and is not limited to the specific structure of the above embodiments. In conclusion, the scope of the present invention should include those changes or substitutions and modifications which are obvious to those of ordinary skill in the art.

Claims

1. A broadband phosphor, characterized in that the phosphor has the chemical formula: r_6-a-bCe_aPr_bSi₁₂N_22-4eC_3eWherein R is selected from Lu³⁺And Y³⁺One or two of the above, Ce is Ce³⁺Pr is Pr³⁺Si is Si⁴⁺N is N^3-C is C^4-A, b and e are mole numbers, a is more than or equal to 0 and less than or equal to 0.6 in the value range of a, b is more than or equal to 0.0006 and less than or equal to 0.12 in the value range of b, and e is more than or equal to 0 and less than or equal to 1 in the value range of e;

the crystal structure of the phosphor belongs to a monoclinic system space group P2₁C, crystal structure of [ SiN ]₄]Or [ SiCN ]₃]Tetrahedral and built with angle-angle links, and [ N (SiN) present in the structure₃)₄]Or [ C (SiN)₃)₄]A star-like structure.

2. The broadband phosphor of claim 1, wherein when a is 0, the broadband phosphor has a peak wavelength of excitation spectrum in a range of 280nm to 380nm, and emission bands in a range of 490nm to 520nm and 610nm to 650 nm.

3. The broadband phosphor of claim 1, wherein when a is 0< a ≦ 0.6, the broadband phosphor has an excitation spectrum peak wavelength in a range of 280nm to 380nm and an emission band in a range of 490nm to 650 nm.

4. The method of preparing a broad band phosphor of claim 1, comprising the steps of:

according to the formula R_6-a-bCe_aPr_bSi₁₂N_22-4eC_3eThe stoichiometric ratio of each element in the composition is measured to contain Y³⁺Compound of (1) and composition containing Lu³⁺Compound of (2) and containing Ce³⁺Compound of (1), containing Pr³⁺A compound of (1), containingWith Si⁴⁺Grinding and uniformly mixing the compound (A) and the carbon simple substance or the organic substance containing the carbon element to obtain a mixture;

and heating the mixture in a nitrogen atmosphere to a sintering temperature of 1500-1700 ℃, wherein the sintering time is 4-10 h, taking out a sample after the furnace body is cooled, and grinding, washing, sieving and drying the sample to obtain the broadband fluorescent powder.

5. The method of claim 4, wherein said Y is included³⁺The compound of (A) is a compound containing Y³⁺One or more of oxides, nitrides and nitrates of ions; the content of Lu³⁺The compound of (A) is Lu-containing³⁺One or more of oxides, nitrides and nitrates of (a); said containing Ce³⁺The compound of (A) is Ce-containing³⁺One or more of oxides, nitrides and nitrates of (a); the component containing Pr³⁺The compound of (A) is a compound containing Pr³⁺One or more of oxides, nitrides, nitrates and fluorides of (a); said Si-containing compound⁴⁺The compound of (A) is Si-containing⁴⁺One or more of oxides, nitrides and carbides of (a).

6. A light emitting device characterized in that the broad band phosphor of any one of claims 1 to 3 is used as a light conversion material, or the broad band phosphor prepared by the method of claim 4 or 5 is used as a light conversion material.

7. A method for manufacturing a light-emitting device according to claim 6, comprising the steps of:

mixing the broadband fluorescent powder with a binder to obtain slurry;

and coating the slurry on an excitation light source chip, and curing to obtain the light-emitting device.

8. The method of manufacturing a light emitting device according to claim 7, wherein the adhesive is an epoxy resin or a silicone material.

9. The method for manufacturing a light-emitting device according to claim 7, wherein the excitation light source chip is a 280nm to 380nm ultraviolet LED light source chip or a laser light source chip.