A luminescent material for plant lighting and its preparation method

Abstract

This invention claims protection for a luminescent material for plant lighting and its preparation method. The chemical formula of the luminescent material is BaY. 2(1‑x) Al2Ga3O 12 :xBi 3+ ,yK + Where 0.005≤x≤0.03, 0.01≤y≤0.03. This luminescent material was synthesized via a high-temperature solid-state method with a sintering temperature of 1350℃-1450℃. This method is simple and easy to industrialize. The luminescent material, doped with Bi₂O₃, exhibits both blue and red light emission under ultraviolet wavelength excitation. The emission wavelengths of this luminescent material cover the absorption spectra of chlorophyll a, chlorophyll b, carotenoids, and phytochrome Pr, and its ability to simultaneously provide red and blue light emission has significant application value in plant growth lighting.

Description

Technical Field

[0001] This invention belongs to the field of luminescent materials technology, specifically relating to a photoluminescent material for plant lighting and its preparation method. Background Technology

[0002] With advancements in technology and agricultural planting techniques, indoor scientific planting has become widespread. Compared to traditional lighting fixtures, LED lights offer energy savings of over 80% for plant lighting, resulting in significant energy benefits. LED lights also boast advantages such as long lifespan, environmental friendliness, safety, and adjustable color temperature to meet the light requirements of plant growth. Simultaneously, research and development of luminescent materials for plant lighting contributes to the advancement of LED lighting fixtures for plant applications.

[0003] Light is essential for plant growth; plants generally require a certain amount of light at each growth stage to maintain normal life activities, promote photosynthesis, and accelerate chlorophyll synthesis in chloroplasts. Providing adequate light ensures fuller, more robust leaf growth. Plants primarily absorb blue light in the 400-500nm range and red light in the 600-700nm range. Blue light irradiation promotes thicker stems and inhibits leaf growth; red light irradiation prevents chlorophyll decomposition, allowing plants to convert light energy into more chemical energy for stronger growth. Furthermore, red light irradiation is also necessary for normal flowering and fruiting. Therefore, both blue and red light are indispensable for plant lighting. Developing a color-tunable luminescent material that emits both blue light in the 400-500nm range and red light in the 600-700nm range holds great promise for plant lighting applications.

[0004] Patent CN 114752380 B discloses a blue light-emitting device for plant lighting, a lighting apparatus, and its application. This invention provides a luminescent material with the chemical formula (M... 3-a-x A a )Mg(Si 2-b D b )O 8-a E a :xEu 2+ (0.001≤a≤0.3;0≤b≤0.3;0.001≤x≤0.4), where M is at least one of Sr, Ca, and Ba; A is at least one of Na and K; D is Ge; and E is at least one of Cl and F. This invention broadens the blue light emission peak, promoting the absorption of carotenoids; however, it still lacks absorption in the red light band. The red light band is also essential for plant growth, flowering, and fruiting, and is very important for the phytochrome Pr.

[0005] The patent publication number CN116769476A was also retrieved, which discloses a near-infrared phosphor for plant lighting and its preparation method. The near-infrared phosphor of this invention has the chemical formula Al-m-lBlCnAlx-y-nGa11-xO17.5-m:yCr3+, where A is one or more of divalent Ca, Sr, and Ba; B is one or more of trivalent La, Sc, Lu, and Y; and C is one or more of divalent Zn, Mg, and Mn, wherein 0≤m<1, 0≤l<1, 0≤n<1, 0≤x≤11, and 0≤y≤0.5. The phosphor is prepared by a high-temperature solid-state method, which is simple in process. The near-infrared phosphor of this invention can emit broadband near-infrared light of 600-1100nm under visible light excitation at wavelengths of 350-700nm. The emission spectrum of this phosphor matches well with the absorption spectrum of plant pigments, and it has important application value in plant growth.

[0006] Patent CN 116769476 A discloses a near-infrared phosphor for plant lighting and its preparation method. The chemical formula of the near-infrared phosphor in this invention is A. 1-m-l B l C n Al x-y-n Ga 11-x O 17.5-m :yCr 3+ A is one or more of divalent Ca, Sr, and Ba; B is one or more of trivalent La, Sc, Lu, and Y; and C is one or more of divalent Zn, Mg, and Mn, wherein 0 ≤ m < 1, 0 ≤ l < 1, 0 ≤ n < 1, 0 ≤ x ≤ 11, and 0 ≤ y ≤ 0.5. The invented near-infrared phosphor can emit broadband near-infrared light in the 600-1100 nm range, providing the deep red emission of 650-750 nm wavelength required by the phytochrome. The emission spectrum of this phosphor is similar to that of the plant phytochrome P. FR The absorption spectrum is matched. However, it lacks the broadband absorption between 400-500 nm for chlorophyll required for plant photosynthesis and carotenoid-β required for growth, and cannot simultaneously provide the blue and red light required for plant growth. This invention utilizes Bi 2+ and Bi 3+ The coexistence of luminescent materials can simultaneously provide the absorption of blue and red light bands required by plants. Summary of the Invention

[0007] This invention aims to solve the problems of the prior art mentioned above. It proposes a luminescent material for plant lighting and its preparation method. The technical solution of this invention is as follows:

[0008] A luminescent material for plant lighting, the chemical formula of which is BaY 2(1-x)Al2Ga3O 12 :xBi 3+ ,yK + Where 0.005≤x≤0.03, K + For co-solvent ions, 0.01≤y≤0.03.

[0009] A method for preparing a luminescent material for plant lighting includes the following steps:

[0010] (1) Based on the chemical formula of the luminescent material BaY 2(1-x) Al2Ga3O 12 :xBi 3+ ,yK + The raw materials were weighed in the following stoichiometric ratios: 1:2(1-x):2:3:x:y, and the raw materials were BaCO3, Y2O3, Ga2O3, Al2O3, Bi2O3, and K2CO3.

[0011] (2) Place all the raw materials weighed in step (1) into an agate mortar and grind them thoroughly;

[0012] (3) The precursor ground in step (2) is placed into a corundum crucible, placed in a box-type muffle furnace for high-temperature sintering, and then the sample is naturally cooled to room temperature and taken out.

[0013] (4) The powder sample obtained in step (3) is ground thoroughly in an agate mortar to obtain the final luminescent material for plant lighting.

[0014] Furthermore, in step (1), the raw material K2CO3 is a co-solvent.

[0015] Furthermore, in step (1), the amount of co-solvent added is 1-3% of the molar mass ratio of the raw materials.

[0016] Furthermore, the grinding time in step (2) is 30-40 minutes.

[0017] Furthermore, in step (3), the sintering temperature is 1350℃-1450℃, the sintering holding time is 4h, and sintering is carried out in an air atmosphere.

[0018] Furthermore, in step (4), the grinding time of the sintered sample is 10-20 min.

[0019] The advantages and beneficial effects of this invention are as follows:

[0020] 1. This invention can simultaneously emit blue light and red light, and can be effectively excited by ultraviolet and yellow LED chips to achieve adjustable light color. The emission spectrum is well matched with the absorption of plant chlorophyll a, chlorophyll b, carotenoids- and phytochrome Pr, and has excellent application prospects for plant growth lighting.

[0021] 2. This invention employs a conventional high-temperature solid-state method, requiring no additional gaseous atmosphere conditions. The synthesis method is simple, efficient, and easily industrialized for large-scale production of finished products. Furthermore, it utilizes the inherent redox properties of the raw material Bi₂O₃ to... 2+ and Bi 3+ The light coexists with luminescent materials, providing broadband blue light emission of 400-500nm and red light emission of 600-700nm required for plant growth. Attached Figure Description

[0022] Figure 1 The present invention provides excitation and emission spectra of preferred embodiment 1.

[0023] Figure 2 The emission spectrum of Example 1 excited at 286 nm is shown.

[0024] Figure 3 The emission spectrum of Example 1 excited at 571 nm is shown.

[0025] Figure 4 This is a comparison of the emission spectrum of Example 1 and the relative absorption of pigments during photosynthesis.

[0026] Figure 5 The following is a comparison of the emission spectra of Examples 1, 3, and 4 excited at 286 nm. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and thoroughly described below with reference to the accompanying drawings. The described embodiments are merely some embodiments of the present invention.

[0028] The technical solution of the present invention to solve the above-mentioned technical problems is:

[0029] The purpose of this invention is to provide a luminescent material that simultaneously emits blue and red light, addressing the current limitations of single-emission LED plant lighting. The chemical formula of the luminescent material is BaY. 2(1-x) Al2Ga3O 12 :xBi 3+ ,yK + The material exhibits simultaneous blue light emission of 400-500nm and red light emission of 600-700nm under 284nm excitation, red light emission of 600-700nm under 571nm excitation, and blue light emission of 400-500nm under 375nm excitation. It also demonstrates good structural stability and high emission intensity. The emission peak wavelength of the luminescent material matches well with the absorption of chlorophyll a, chlorophyll b, carotenoids, and phytochrome Pr in plants, showing promising application prospects in plant growth lighting.

[0030] A method for preparing a luminescent material for plant lighting, characterized by comprising the following steps:

[0031] (1) Based on the chemical formula of the luminescent material BaY 2(1-x) Al2Ga3O 12 :xBi 3+ ,yK + The raw materials were weighed in the following stoichiometric ratios: 1:2(1-x):2:3:x:y, and the raw materials were BaCO3 (AR Chengdu Kelong Chemical Reagent Factory), Y2O3 (4N Hunan Rare Earth Research Institute), Ga2O3 (4N Hunan Rare Earth Research Institute), Al2O3 (4N Tianjin Guangfu Fine Chemical Research Institute), Bi2O3 (4N Chengdu Kelong Chemical Reagent Factory), and K2CO3 (AR Chengdu Kelong Chemical Reagent Factory).

[0032] (2) Place all the raw materials weighed in step (1) into an agate mortar and grind them thoroughly;

[0033] (3) The precursor ground in step (2) is placed in a corundum crucible, placed in a box-type muffle furnace for high-temperature sintering, and then the sample is naturally cooled to room temperature and taken out.

[0034] (4) The powder sample obtained in step (3) is ground thoroughly in an agate mortar to obtain the final luminescent material for plant lighting.

[0035] Example 1

[0036] In this embodiment, the photoluminescent material used for plant lighting has the chemical formula BaY. 1.98 Al2Ga3O 12 0.01Bi 3+ 0.03K +Weigh 0.7894g BaCO3, 0.8942g Y2O3, 1.1246g Ga2O3, 0.4078g Al2O3, 0.0186g Bi2O3, and 0.0083g K2CO3 according to the stoichiometric ratio. Place all raw materials into an agate mortar and grind them thoroughly for 30-40 minutes. Then, put them into a corundum crucible and finally place them in a box-type muffle furnace for high-temperature sintering in an air atmosphere. The first stage involves heating within the temperature range of 25℃-400℃ for 2 hours; the second stage involves heating within the temperature range of 400℃-600℃ for 2 hours; the third stage involves heating within the temperature range of 600℃-900℃ for 2 hours; the fourth stage involves heating within the temperature range of 900℃-1100℃ for 3 hours; the fifth stage involves heating within the temperature range of 1100℃-1200℃ for 2 hours; the sixth stage involves heating within the temperature range of 1200℃-1300℃ for 3 hours; the seventh stage involves heating within the temperature range of 1300℃-1350℃ for 2 hours; the eighth stage involves sintering at 1350℃ for 4 hours; and the ninth stage involves cooling from 1350℃ to 500℃ for 4 hours, followed by natural cooling to room temperature. The sample is then removed and thoroughly ground in an agate mortar to obtain the luminescent material for plant lighting in Example 1. The grinding time is 10-20 minutes.

[0037] Figure 1 The excitation and emission spectra of Example 1 show that it exhibits efficient narrow-band blue light emission under optimal excitation at 375 nm near-ultraviolet light. The emission peak is mainly located between 400-450 nm, attributed to Bi. 3+ ion 3 P1→ 1 The transition between the S0 energy levels is the most efficient for chlorophyll a in this wavelength range. Figure 2 and Figure 3 These are the emission spectra of Example 1 under excitation at 286 nm and 571 nm, respectively. The emission peak between 400-500 nm is attributed to Bi. 3+ ion 3 P1→ 1 The transition between S0 levels, with the emission peak located between 600-700 nm, is attributed to Bi. 2+ ion 2 P 3 / 2 → 2 P 1 / 2 Transitions between energy levels. Figure 4 As shown, Example 1 can simultaneously achieve broadband blue and red light emission, which closely matches the absorption spectra of chlorophyll a, chlorophyll b, carotenoids- and phytochrome Pr, and has important application value in plant growth lighting.

[0038] Example 2

[0039] In this embodiment, the photoluminescent material used for plant lighting has the chemical formula BaY. 1.98 Al2Ga3O 12 0.01Bi 3+ 0.02K + According to the stoichiometric ratio, 0.7894g BaCO3, 0.8942g Y2O3, 1.1246g Ga2O3, 0.4078g Al2O3, 0.0186g Bi2O3, and 0.0055g K2CO3 were weighed and thoroughly ground in an agate mortar for 30-40 minutes. The mixture was then placed in a corundum crucible and finally sintered at high temperature in a box-type muffle furnace at 1350℃ under air atmosphere. Compared to Example 1, the flux content was changed. The heating, holding, and cooling times at each stage of sintering in this example were the same as in Example 1. After sintering, the sample was removed and thoroughly ground in an agate mortar to obtain the luminescent material for plant lighting in Example 2, with a grinding time of 10-20 minutes.

[0040] Example 3

[0041] This embodiment has the same chemical formula as Example 1, both being BaY. 1.98 Al2Ga3O 12 0.01Bi 3+ 0.03K + The initial weighing and grinding of raw materials were consistent with those in Example 1, but the sintering stage in the box-type muffle furnace differed. The sintering atmosphere is air, and the sintering temperature is 1400℃. The first stage involves heating for 2 hours within the temperature range of 25℃-400℃; the second stage involves heating for 2 hours within the temperature range of 400℃-600℃; the third stage involves heating for 2 hours within the temperature range of 600℃-900℃; the fourth stage involves heating for 3 hours within the temperature range of 900℃-1100℃; the fifth stage involves heating for 2 hours within the temperature range of 1100℃-1200℃; the sixth stage involves heating for 3 hours within the temperature range of 1200℃-1300℃; the seventh stage involves heating for 4 hours within the temperature range of 1300℃-1400℃; the eighth stage involves holding the sinter at 1400℃ for 4 hours; and the ninth stage involves cooling from 1400℃ to 500℃ for 5 hours, followed by natural cooling to room temperature. After taking out the sample and grinding it thoroughly in an agate mortar, the luminescent material for plant lighting in Example 1 was obtained. The grinding time was 10-20 minutes.

[0042] Example 4

[0043] This embodiment has the same chemical formula as Example 1, both being BaY. 1.98 Al2Ga3O12 0.01Bi 3+ 0.03K + The initial raw material weighing and grinding / mixing were consistent with Example 1, but the sintering stage in the box-type muffle furnace differed. The sintering atmosphere was air, and the sintering temperature was 1450℃. The heating time was as follows: first stage: 25℃-400℃, heating time 2 hours; second stage: 400℃-600℃, heating time 2 hours; third stage: 600℃-900℃, heating time 2 hours; fourth stage: 900℃-1100℃, heating time 3 hours; fifth stage: 1100℃-1200℃, heating time... The heating time was 2 hours. In the sixth stage, the heating time was 3 hours within the 1200℃-1300℃ temperature range. In the seventh stage, the heating time was 4 hours within the 1300℃-1400℃ temperature range. In the eighth stage, the heating time was 2 hours within the 1400℃-1450℃ temperature range. In the ninth stage, the temperature was held at 1450℃ for 4 hours. In the tenth stage, the temperature was lowered from 1450℃ to 500℃ for 5 hours, and then the furnace was allowed to cool naturally to room temperature. The sample was then removed and thoroughly ground in an agate mortar to obtain the luminescent material for plant lighting in Example 1. The grinding time was 10-20 minutes. Figure 5 A comparison of the emission spectra of Examples 1, 3, and 4 under 286nm excitation shows that the shape of the emission peak remains basically unchanged as the sintering temperature increases, with the highest emission intensity observed at 1400℃.

[0044] The systems, devices, modules, or units described in the above embodiments can be implemented by computer chips or entities, or by products with certain functions.

[0045] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0046] The above embodiments should be understood as illustrative only and not as limiting the scope of protection of the present invention. After reading the description of the present invention, those skilled in the art can make various alterations or modifications to the present invention, and these equivalent changes and modifications also fall within the scope defined by the claims of the present invention.

Claims

1. A method for preparing a luminescent material for plant lighting, characterized in that, Includes the following steps: (1) Based on the chemical formula of the luminescent material BaY 2(1-x) Al2Ga3O 12 :x(Bi 2+ Bi 3+ ), yK + The stoichiometric ratio of raw materials is 1:2(1-x):2:3:x:y, and the raw materials are BaCO3, Y2O3, Ga2O3, Al2O3, Bi2O3, and K2CO3; wherein 0.005≤x≤0.03, K + For flux ions, 0.01≤y≤0.03; (2) Place all the raw materials weighed in step (1) into an agate mortar and grind them thoroughly; (3) The precursor ground in step (2) is placed into a corundum crucible, placed in a box-type muffle furnace for high-temperature sintering, and then the sample is naturally cooled to room temperature and taken out. (4) The powder sample obtained in step (3) is ground thoroughly in an agate mortar to obtain the final luminescent material for plant lighting.

2. The preparation method according to claim 1, characterized in that, In step (1), the raw material K2CO3 is a flux.

3. The preparation method according to claim 1, characterized in that, In step (1), the amount of flux added is 1-3% of the molar mass ratio of the raw materials.

4. The preparation method according to claim 1, characterized in that, The grinding time in step (2) is 30-40 minutes.

5. The preparation method according to claim 1, characterized in that, In step (3), the sintering temperature is 1350℃-1450℃, the sintering holding time is 4h, and the sintering is carried out in an air atmosphere.

6. The preparation method according to claim 1, characterized in that, The grinding time of the sintered sample in step (4) is 10-20 minutes.

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