A Eu 3+ Doped boroaluminate red-orange luminescent material, process for its preparation and use

Abstract

This disclosure proposes an Eu 3+ This paper discusses doped boroaluminate red-orange luminescent materials, their preparation methods, and applications, belonging to the field of luminescent material technology. Specifically, Eu... 3+ The chemical formula of the doped boroaluminate red-orange luminescent material is Li4Al2B4O. 11 :4xEu 3+ , where x is Eu 3+ Li + The molar number of the material is such that 0.005 ≤ x ≤ 0.04. This material can be effectively excited by near-ultraviolet and blue light wavelengths and emits a sharp spectrum with a peak wavelength at 593 nm. The red-orange emission exhibits high chromaticity, high luminescence intensity, and good thermal stability. This Eu... 3+ Doped boroaluminate red-orange luminescent materials can be combined with near-ultraviolet or blue light semiconductor chips to prepare corresponding white LED lighting devices.

Description

TECHNICAL FIELD

[0001] The present disclosure belongs to the technical field of luminescent materials, and particularly relates to a Eu 3+ doped boroaluminate red-orange luminescent material, a preparation method and application thereof. BACKGROUND

[0002] Nowadays, white light LED solid-state lighting based on semiconductor chips is the most attractive green light source, and has a very broad application market. White light LED achieved by using InGaN semiconductor chips and three primary color phosphor packaging with near ultraviolet light (350-410 nm) has become one of the hotspots in the field of research and development, and is considered to be the dominant of the new generation of white light LED lighting. High-efficiency near-ultraviolet-excited fluorescent powder is also one of the hotspots in the research and development of luminescent materials. At present, InGaN-based light-emitting diodes with a wavelength of 350-470 nm are commonly used as excitation light sources for white light LEDs internationally, so the excitation spectrum of the fluorescent powder must also be in this wavelength range. In addition, high-quality fluorescent powder also needs to have the following characteristics: the emission peak should be concentrated in a specific wavelength range, the colorimetric value is high, it has high quantum efficiency, good excitation light absorption rate, excellent thermal stability, and small and uniform particles. Undoubtedly, among the luminescent materials that meet these conditions, rare earth ion-activated fluorescent powder is the most important candidate. Rare earth ion-activated fluorescent powder can emit light spectra of different wavelengths, producing colorful light effects, and plays an important role in the fields of light emission and display.

[0003] At present, traditional fluorescent powders such as Y2O2S:Eu 3+ , Y2O3:Eu 3+ , etc. have weak excitation light in the near-ultraviolet and blue light regions, poor high-temperature stability and luminescent efficiency. For example, the traditional red fluorescent powder Y2O3:Eu 3+ , YVO4:Eu 3+ has the problems of emission of toxic waste gas during preparation, high sintering temperature, etc. SUMMARY

[0004] The present disclosure aims to at least solve one of the technical problems existing in the prior art, and provide a Eu 3+ doped boroaluminate red-orange luminescent material, a preparation method and application thereof.

[0005] In one aspect of the present disclosure, a Eu 3+ doped boroaluminate red-orange luminescent material is provided, the chemical formula of the red-orange luminescent material is Li4Al2B4O 11 :4xEu 3+ , wherein x is the mole number of Eu 3+ replacing Li + , and 0.005≤x≤0.04.

[0006] Optionally, the red-orange light emitting material is capable of emitting orange-red light with a sharp characteristic peak at 593 nm under excitation of ultraviolet-blue light.

[0007] In another aspect of the present disclosure, a method for preparing the Eu 3+ The method for preparing the doped boro-aluminate red-orange light emitting material comprises:

[0008] The chemical formula of the doped boro-aluminate red-orange light emitting material is Li4Al2B4O 11 :4xEu 3+ The stoichiometric ratio of each element is 4:2:4:4:4x, wherein 0.005≤x≤0.04. The compound containing lithium ions, the compound containing aluminum ions, the compound containing boron ions, and the compound containing europium ions are weighed respectively, and 1wt% to 5wt% of the complexing agent is added to each of the above raw materials.

[0009] Each of the weighed reagents is dissolved in deionized water or nitric acid, and then 1-5wt% of the complexing agent is added to each of the reagents, and stirred for 1-2 hours to obtain a transparent precursor solution of each raw material.

[0010] The transparent precursor solutions of the above raw materials are slowly mixed, stirred at a temperature of 40-95℃ for 1-5 hours, and then left to stand and dry to obtain a precursor powder.

[0011] The above precursor powder is placed in a muffle furnace and calcined at a temperature of 720-800℃ for 1-10 hours, and then naturally cooled to room temperature to obtain a Eu 3+ doped boro-aluminate red-orange light emitting material.

[0012] Optionally, the compound containing lithium ions is one or more of lithium oxide, lithium nitrate, lithium carbonate, and lithium hydroxide.

[0013] Optionally, the compound containing aluminum ions is one or more of aluminum oxide, aluminum nitrate, and aluminum hydroxide.

[0014] Optionally, the compound containing boron ions is one or more of diboron trioxide and boric acid.

[0015] Optionally, the compound containing europium ions is one or more of europium oxide and europium nitrate.

[0016] Optionally, the complexing agent is citric acid or oxalic acid.

[0017] In another aspect of the present disclosure, a method for preparing the Eu 3+ application of the doped boro-aluminate red-orange light emitting material, and the Eu 3+The doped boron aluminic acid red-orange luminescent material is applied to white light emitting LED based on near ultraviolet and blue light semiconductor chip excitation.

[0018] The present disclosure provides a Eu 3+ The present disclosure provides a doped boron aluminic acid red-orange luminescent material, a preparation method and application thereof. The chemical formula of the red-orange luminescent material is Li4Al2B4O 11 :4xEu 3+ , wherein x is the mole number of Eu 3+ replacing Li + , and 0.005≤x≤0.04. The material can be effectively excited by near ultraviolet and blue light, and emit sharp spectrum with wavelength peak at 593 nm. The red-orange luminescent material has high chroma purity, high luminescent intensity and good thermal stability. The Eu 3+ doped boron aluminic acid red-orange luminescent material can be combined with near ultraviolet or blue light semiconductor chip to prepare corresponding white light LED illuminating device. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The present disclosure provides a flow chart of the preparation method of the Eu 3+ doped boron aluminic acid red-orange luminescent material;

[0020] Figure 2 The present disclosure provides XRD diffraction pattern of the sample prepared in Example 1, 2, 3 and 4, and comparison with X-ray diffraction standard card PDF#28-0548;

[0021] Figure 3 The present disclosure provides SEM pattern of the sample prepared in Example 1;

[0022] Figure 4 The present disclosure provides excitation spectrum of the sample prepared in Example 1;

[0023] Figure 5 The present disclosure provides luminescent spectrum of the sample prepared in Example 1;

[0024] Figure 6 The present disclosure provides luminescent decay curve of the sample prepared in Example 1;

[0025] Figure 7 The present disclosure provides excitation spectrum of the sample prepared in Example 2;

[0026] Figure 8 The present disclosure provides luminescent spectrum of the sample prepared in Example 2;

[0027] Figure 9 The present disclosure provides luminescent decay curve of the sample prepared in Example 2;

[0028] Figure 10Excitation spectrum of the sample prepared for Example 3 of the present disclosure;

[0029] Figure 11 Luminescence spectrum of the sample prepared for Example 3 of the present disclosure;

[0030] Figure 12 Luminescence decay curve of the sample prepared for Example 3 of the present disclosure;

[0031] Figure 13 Excitation spectrum of the sample prepared for Example 4 of the present disclosure;

[0032] Figure 14 Luminescence spectrum of the sample prepared for Example 4 of the present disclosure;

[0033] Figure 15 Luminescence decay curve of the sample prepared for Example 4 of the present disclosure. DETAILED DESCRIPTION

[0034] In order to make the technical solution of the present disclosure better understood by those skilled in the art, the present disclosure will be described in further detail below in combination with the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present disclosure and are part of the embodiments of the present disclosure, but not all the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present disclosure.

[0035] In one aspect of the present disclosure, a Eu 3+ doped boron aluminic acid red-orange luminescent material, the chemical formula of the red-orange luminescent material is Li4Al2B4O 11 :4xEu 3+ , wherein x is the mole number of Eu 3+ replacing Li + , and 0.005≤x≤0.04.

[0036] In the present embodiment, the crystal lattice of the boron aluminic acid matrix Li4Al2B4O 11 is combined by strong covalent bonds of Al-O and B-O, and the smallest metal ion Li fills in the crystal lattice. The luminescent spectrum of the fluorescent powder is very sharp, the chroma of the red-orange luminescent is pure, and the luminescent efficiency and thermal stability of the luminescence are good. Compared with the traditional fluorescent powder such as Y2O2S:Eu 3+ , Y2O3:Eu 3+ , etc., the fluorescent powder of the present disclosure has strong excitation in the near ultraviolet (around 400 nm) and blue light region (around 450 nm), and is very matched with the luminescent wavelength of the commercial InGaN-based light emitting diode.

[0037] In some preferred embodiments, the red-orange light emitting material is capable of emitting orange-red light with a sharp characteristic peak at 593 nm under excitation of ultraviolet-blue light.

[0038] As shown in Figure 1 , in one aspect of the present disclosure, a method for preparing the Eu 3+ doped boron-aluminate red-orange light emitting material is provided, which comprises the following steps S110-S140:

[0039] S110, each element stoichiometric ratio in the chemical formula Li4Al2B4O 11 :4xEu 3+ is 0.005≤x≤0.04, and each of the lithium ion containing compound, the aluminum ion containing compound, the boron ion containing compound, and the europium ion containing compound is weighed, and 1wt%-5wt% of the complexing agent of each raw material is further weighed.

[0040] In some preferred embodiments, the lithium ion (Li + ) containing compound is one or a combination of lithium oxide, lithium nitrate, lithium carbonate, and lithium hydroxide.

[0041] In some other preferred embodiments, the aluminum ion (Al 3+ ) containing compound is one or a combination of aluminum oxide, aluminum nitrate, and aluminum hydroxide.

[0042] In some other preferred embodiments, the boron ion (B 3+ ) containing compound is one or a combination of diboron trioxide and boric acid.

[0043] In some other preferred embodiments, the (Eu 3+ ) containing compound is one or a combination of europium oxide and europium nitrate.

[0044] In some other preferred embodiments, the complexing agent is citric acid or oxalic acid.

[0045] S120, each of the weighed reagents is dissolved in deionized water or nitric acid, and then 1-5wt% of the complexing agent of each raw material is added to each reagent, and stirred for 1-2 hours to obtain a transparent precursor solution of each raw material.

[0046] It should be noted that in step S120, each of the weighed reagents is dissolved in deionized water or nitric acid, and the complexing agent is added to each reagent to form a transparent precursor solution, wherein the amount of the complexing agent added to each reagent is 1-5wt% of the mass of each raw material, for example, 1wt%, 2wt%, 3wt%, 4wt%, or 5wt%.

[0047] S130, slowly mix the transparent precursor solution of each raw material above, stir at a temperature of 40-95℃ for 1-5 hours, stand, dry to obtain a precursor powder.

[0048] In some preferred embodiments, the temperature is 40℃, 50℃, 60℃, 70℃, 80℃, 90℃, 95℃, and the stirring time is 1 hour, 2 hours, 3 hours, 4 hours, 5 hours.

[0049] S140, put the precursor powder above into a muffle furnace to calcine, the calcination temperature is 720-800℃, the calcination time is 1-10 hours, and a Eu 3+ doped boroaluminate red-orange luminescent material is obtained after natural cooling to room temperature.

[0050] In some preferred embodiments, the calcination temperature is 720℃, 750℃, 780℃, 800℃, etc., and the calcination time is 1 hour, 3 hours, 5 hours, 7 hours, 10 hours, etc.

[0051] Compared with traditional red luminescent powder Y2O3:Eu 3+ , YVO4:Eu 3+ , etc., the fluorescent powder powder is prepared by using a chemical sol-gel method in the embodiment, the preparation method is simple, the prepared material has a single phase, fine particle size, raw materials are easy to obtain, has good repeatability, no pollution, no waste gas and waste liquid emission, low sintering temperature, energy saving, and easy production.

[0052] In another aspect of the disclosure, an application of a Eu 3+ doped boroaluminate red-orange luminescent material is provided, and the Eu 3+ doped boroaluminate red-orange luminescent material is applied to a white light emitting LED based on near-ultraviolet and blue light semiconductor chip excitation.

[0053] The preparation method and performance of the Eu 3+ doped boroaluminate red-orange luminescent material will be further described below in combination with specific embodiments.

[0054] Embodiment 1:

[0055] According to the chemical formula Li 3.98 Eu 0.02 Al2B4O 11The stoichiometric ratio of each element is as follows: 13.72 g of lithium nitrate, 37.51 g of aluminum nitrate, 12.37 g of boric acid, and 0.446 g of europium nitrate. The weighed lithium nitrate is dissolved in ionized water, and 0.69 g of citric acid is added; the aluminum nitrate is dissolved in ionized water, and 1.88 g of citric acid is added; the boric acid is dissolved in ionized water, and 0.62 g of citric acid is added; the europium nitrate is dissolved in ionized water, and 0.03 g of citric acid is added; the above solutions are stirred for 1 hour to obtain transparent precursor solutions of the respective raw materials; the four precursor solutions are slowly mixed, stirred at 95°C for 1 hour, and left to stand and dry to obtain fluffy precursor powder; the precursor powder is placed in a muffle furnace and calcined at a temperature of 800°C for 1 hour, and then naturally cooled to room temperature to obtain a Eu 3+ The doped boron-aluminum acid red-orange luminescent material.

[0056] Referring to the attached Figure 2 is the X-ray powder diffraction pattern of the sample prepared according to Example 1, compared with the standard card PDF #28-0548, and the results show that the sample is a pure phase material.

[0057] Referring to the attached Figure 3 is the SEM image of the sample prepared according to Example 1, and the results show that the sample is a fine particle with uniform particle size, and the particle size is 100-300 nm.

[0058] Referring to the attached Figure 4 is the excitation spectrum of the sample prepared according to Example 1, and it can be seen that the sample exhibits good excitation in the ultraviolet-blue light range.

[0059] Referring to the attached Figure 5 is the luminescence spectrum of the sample prepared according to Example 1, and it can be seen that the strongest luminescence peak is located at 593 nm, and the luminescence peak is sharp, and the chroma of the red-orange luminescence is pure.

[0060] Referring to the attached Figure 6 is the luminescence decay curve of the sample prepared according to Example 1, and the luminescence lifetime is 1.47 ms, which is the characteristic luminescence decay of Eu 3+ ion. It can meet the needs of luminescent display without afterglow phenomenon.

[0061] Example 2

[0062] According to the chemical formula Li 3.96 Eu 0.04 Al2B4O 11The stoichiometric ratio of each element is as follows: 14.47 g of lithium nitrate, 39.76 g of aluminum nitrate, 13.11 g of boric acid, and 0.95 g of europium nitrate. The weighed lithium nitrate is dissolved in ionized water, and 0.58 g of citric acid is added; the aluminum nitrate is dissolved in ionized water, and 1.59 g of citric acid is added; the boric acid is dissolved in ionized water, and 0.53 g of citric acid is added; the europium nitrate is dissolved in ionized water, and 0.04 g of citric acid is added; the above solutions are stirred for 2 hours to obtain transparent precursor solutions of the respective raw materials; the four precursor solutions are slowly mixed, stirred at 40°C for 5 hours, and left to stand and dry to obtain fluffy precursor powder; the precursor powder is placed in a muffle furnace and calcined at a temperature of 720°C for 10 hours, and then naturally cooled to room temperature to obtain a Eu 3+ The doped boron-aluminum acid red-orange luminescent material.

[0063] See the attached Figure 2 is the X-ray powder diffraction pattern of the sample prepared according to Example 2, compared with the standard card PDF # 28-0548, and the results show that the sample is a pure phase material.

[0064] See the attached Figure 7 is the excitation spectrum of the sample prepared according to Example 2, and it can be seen that the sample exhibits good excitation in the ultraviolet-blue light range.

[0065] See the attached Figure 8 is the luminescence spectrum of the sample prepared according to Example 2, and it can be seen that the strongest luminescence peak is located at 593 nm, and the luminescence peak is sharp, and the chroma of the red-orange luminescence is pure.

[0066] See the attached Figure 9 is the luminescence decay curve of the sample prepared according to Example 2, and the luminescence lifetime is 1.32 ms, which is the characteristic luminescence decay of Eu 3+ ion. It can meet the needs of luminescent display without afterglow phenomenon.

[0067] Example 3

[0068] According to the chemical formula Li 3.88 Eu 0.12 Al2B4O 11The stoichiometric ratio of each element is as follows: 12.84 g of lithium nitrate, 36.01 g of aluminum nitrate, 11.87 g of boric acid, and 2.57 g of europium nitrate. The weighed lithium nitrate is dissolved in ionized water, and 0.26 g of citric acid is added; the weighed aluminum nitrate is dissolved in ionized water, and 0.72 g of citric acid is added; the weighed boric acid is dissolved in ionized water, and 0.24 g of citric acid is added; the weighed europium nitrate is dissolved in ionized water, and 0.05 g of citric acid is added; the above solutions are stirred for 2 hours to obtain transparent precursor solutions of the respective raw materials; the above four precursor solutions are slowly mixed, stirred at 60°C for 2 hours, and left to stand and dry to obtain fluffy precursor powder; the above precursor powder is placed in a muffle furnace and calcined at a temperature of 780°C for 5 hours, and then naturally cooled to room temperature to obtain a Eu 3+ The doped boron-aluminum acid red-orange luminescent material.

[0069] See the attached Figure 2 is the X-ray powder diffraction pattern of the sample prepared according to Example 3, compared with the standard card PDF # 28-0548, and the results show that the sample is a pure phase material.

[0070] See the attached Figure 10 is the excitation spectrum of the sample prepared according to Example 3, and it can be seen that the sample exhibits good excitation in the ultraviolet-blue light range.

[0071] See the attached Figure 11 is the luminescence spectrum of the sample prepared according to Example 3, and it can be seen that the strongest luminescence peak is located at 593 nm, and the luminescence peak is sharp, and the red-orange luminescence has high color purity.

[0072] See the attached Figure 12 is the luminescence decay curve of the sample prepared according to Example 3, and the luminescence lifetime is 1.25 ms, which is the characteristic luminescence decay of Eu 3+ ion. It can meet the needs of luminescent display without afterglow phenomenon.

[0073] Example 4

[0074] According to the chemical formula Li 3.84 Eu 0.16 Al2B4O 11The stoichiometric ratio of each element is as follows: 10.59 g of lithium nitrate, 30.01 g of aluminum nitrate, 9.89 g of boric acid, and 2.85 g of europium nitrate. The weighed lithium nitrate is dissolved in ionized water, and 0.53 g of oxalic acid is added; the aluminum nitrate is dissolved in ionized water, and 1.51 g of oxalic acid is added; the boric acid is dissolved in ionized water, and 0.49 g of oxalic acid is added; and the europium nitrate is dissolved in ionized water, and 0.14 g of oxalic acid is added. The above solutions are stirred for 2 hours to obtain transparent precursor solutions of the respective raw materials. The four precursor solutions are slowly mixed, stirred at 60°C for 2 hours, and left to stand and dry to obtain fluffy precursor powder. The precursor powder is placed in a muffle furnace and calcined at a temperature of 780°C for 5 hours. After natural cooling to room temperature, a Eu 3+ doped boroaluminate red-orange luminescent material is obtained.

[0075] See the attached Figure 2 Figure 2 is a comparison of the X-ray powder diffraction pattern of the sample prepared according to Example 4 with the standard card PDF #28-0548, which shows that the sample is a pure phase material.

[0076] See the attached Figure 13 Figure 3 is an excitation spectrum of the sample prepared according to Example 4, which shows that the sample exhibits good excitation in the ultraviolet-blue light range.

[0077] See the attached Figure 14 Figure 4 is an emission spectrum of the sample prepared according to Example 4, which shows that the strongest emission peak is located at 593 nm, and the emission peak is sharp, with a pure red-orange luminescent chroma.

[0078] See the attached Figure 15 Figure 5 is an emission decay curve of the sample prepared according to Example 4, which has a luminescent lifetime of 1.13 ms, characteristic of Eu 3+ ion luminescence decay. It can meet the needs of luminescent display without appearing afterglow.

[0079] The present disclosure proposes a Eu 3+ doped boroaluminate red-orange luminescent material, a preparation method and application thereof, which has the following beneficial effects relative to the prior art:

[0080] First, the boroaluminate matrix Li4Al2B4O 11 The crystal lattice is combined by strong covalent bonds of Al-O and B-O, and the smallest metal ion Li fills the crystal lattice. The luminescent spectrum of the fluorescent powder is very sharp, with a pure red-orange luminescent chroma, and the luminescent efficiency and thermal stability are good.

[0081] Second, compared with traditional fluorescent powders such as Y2O2S:Eu 3+ and Y2O3:Eu 3+Compared with the luminescent material, the fluorescent powder prepared by the technical scheme of the present application has strong excitation in the near ultraviolet (400nm) and blue light (450nm) region, and is very matched with the light emitting wavelength of the commercial InGaN-based light emitting diode;

[0082] Thirdly, the red fluorescent powder prepared by the technical scheme of the present application has strong high-temperature stability, has small quenching of light emission at high temperature, and the main peak of light emission at high temperature does not shift, keeping the stability of chromaticity, which is beneficial to realize the preparation of high-power LED.

[0083] Fourthly, compared with the traditional red luminescent powder Y2O3:Eu 3+ , YVO4:Eu 3+ , etc., the preparation method of the fluorescent powder provided by the present application is simple, the prepared material has fine granularity, has no pollution, has no waste gas and waste liquid emission, has low sintering temperature, saves energy consumption, and is easy to produce.

[0084] It can be understood that the above embodiments are only exemplary embodiments for illustrating the principles of the present disclosure, and the present disclosure is not limited thereto. Various modifications and improvements can be made by those skilled in the art without departing from the spirit and essence of the present disclosure, and these modifications and improvements are also considered as the protection scope of the present disclosure.

Claims

1. A Eu 3+ The doped boroaluminate red-orange luminescent material is characterized by, The chemical formula of the red-orange luminescent material is Li4Al2B4O 11 :4xEu 3+ , where x is Eu 3+ Li + The number of moles, and 0.005≤x≤0.

04.

2. The Eu according to claim 1 3+ The doped boroaluminate red-orange luminescent material is characterized by, The red-orange luminescent material can emit orange-red light with a sharp characteristic peak located at 593 nanometers when excited by ultraviolet-blue light.

3. A method for preparing Eu as described in claim 1 or 2 3+ A method for producing a doped boroaluminate red-orange luminescent material, characterized in that, The method includes: According to the chemical formula Li4Al2B4O 11 :4xEu 3+ The stoichiometric ratio of each element in the mixture is such that 0.005≤x≤0.

04. Weigh out compounds containing lithium ions, aluminum ions, boron ions, and europium ions respectively, and then weigh out 1wt% to 5wt% of the complexing agent for each of the above raw materials. Dissolve the weighed reagents in deionized water or nitric acid, and then add 1-5 wt% complexing agent to each reagent. Stir for 1-2 hours to obtain a transparent precursor solution of each raw material. Slowly mix the transparent precursor solutions of the above raw materials, stir for 1 to 5 hours at a temperature of 40 to 95°C, let stand, and dry to obtain precursor powder. The above precursor powders were placed in a muffle furnace and calcined at 720–800°C for 1–10 hours. After natural cooling to room temperature, an Eu was obtained. 3+ Doped borosilicate red-orange luminescent material.

4. The method according to claim 3, characterized in that, The lithium-ion-containing compound is one or more of lithium oxide, lithium nitrate, lithium carbonate, and lithium hydroxide.

5. The method according to claim 3, characterized in that, The aluminum-containing compound is one or more of aluminum oxide, aluminum nitrate, and aluminum hydroxide.

6. The method according to claim 3, characterized in that, The compound containing boron ions is one or more of boron trioxide and boric acid.

7. The method according to claim 3, characterized in that, The compound containing europium ions is one or more of europium oxide and europium nitrate.

8. The method according to claim 3, characterized in that, The complexing agent is citric acid or oxalic acid.

9. A Eu 3+ The application of doped boroaluminate red-orange luminescent materials is characterized by, Using the Eu as described in claim 1 or 2 3+ Doped boroaluminate red-orange luminescent materials are used in white LEDs excited by near-ultraviolet and blue light semiconductor chips.

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