Mn < 4 + >-activated dark red light emitting fluorescent powder for plant growth and preparation method and application thereof

Abstract

The invention discloses Mn < 4 + > activated dark red light emitting fluorescent powder for plant growth as well as a preparation method and application thereof, and belongs to the technical field of solid luminescent materials. The chemical formula of the fluorescent powder is La2-2x-zA2xMg (Al1 / 2-x-zWz, Ta1 / 2 + x) O6: yMn < 4 + >, A is one or a combination of more of Ca, Sr and Ba, and x is more than or equal to 0 and less than or equal to 1 / 2; y is more than 0 and less than or equal to 0.3; z is more than or equal to 0 and less than or equal to 1 / 2; x + z < = 1 / 2. The fluorescent powder synthesized by the invention can effectively convert ultraviolet light and part of visible light in sunlight into far-red light, has the characteristics of high quantum efficiency, good water stability and good overlap between an emission spectrum and an absorption band of plant phytochrome, and is applied to a light conversion film to supplement light for stem and leaf plants and melon and fruit plants; the photosynthesis efficiency can be effectively enhanced, the growth cycle is shortened, the plant yield and the fruit quality are improved, and good application prospects are achieved in the field of plant cultivation.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid luminescent materials and particularly relates to a Mn 4+ Activated deep red light emitting phosphor for plant growth and preparation method and application thereof. Background Art

[0002] Light is one of the key factors affecting plant growth, and plays a vital role in regulating plant growth, development and morphological construction. Light is the main source of energy for plant growth, but plants do not absorb light in the entire wavelength range but selectively. The wavelength of sunlight incident vertically on the ground is 280-3000nm, and only about 5% of the solar radiation spectrum has a significant effect on photosynthesis. The basic requirements of plant growth and development for light are distributed in the blue light (400-500nm), red light (600-690nm) and far-red light (720-740nm) regions. These three regions are mainly responsible for phototropic processes, photosynthesis, photoperiodic response and photomorphogenesis. Studies have shown that the absorption spectrum of chlorophyll a / b in plants is mainly concentrated in the blue light band of 400-460nm, while the photosensitive pigment P r / P fr The absorption peak is located in the red / far-red band of 600-750nm, and the light in other bands is rarely absorbed, and the contribution to photosynthesis is low. In plant cultivation, if the sunlight energy that is not effectively used by plants (ultraviolet light and most of the yellow-green light that is reflected and cannot be absorbed) can be converted into blue light and red / far-red light that can be effectively used by photosynthesis, the photosynthesis of plants can be enhanced, the growth cycle of plants can be shortened, and the yield and quality of plants can be improved.

[0003] There are three main ways to achieve plant supplementary lighting: 1. Traditional light sources such as incandescent lamps, fluorescent lamps and high-pressure sodium lamps; 2. LED plant lamps; 3. Light conversion films for plant growth. Among them, traditional plant light sources have disadvantages such as high energy consumption, low light efficiency, short life, unadjustable spectrum, and mismatch with plant absorption spectrum; new LED supplementary lights have certain application potential, but the spectrum continuity is poor, and the device module structure assembly and the consumption of electrical energy during plant lighting indirectly increase the planting cost, which needs further development and improvement. Light conversion films for plant growth have become another option for plant supplementary lighting. It can convert ultraviolet light and part of visible light in sunlight into blue light and red light, thereby effectively improving the light quality of plants, improving the comprehensive utilization rate of light energy, and promoting plant growth.

[0004] At present, the main red phosphors used for plant growth are: Eu 2+ Activated alkaline earth metal sulfides (such as (Sr,Ca)S:Eu 2 + ), sulfide phosphors have poor chemical stability, are easy to deliquesce and produce harmful gases such as H2S, and are not friendly to the surrounding environment; while Eu 2+ Activated nitride (such as Sr2Si5N8:Eu 2+ ,CaAlSiN3:Eu 2+ ) The synthesis conditions of red phosphor are harsh, requiring high-purity nitride raw materials, and are achieved under high temperature and high pressure (1600°C, above 10 atmospheres) and protective atmosphere. It is difficult to obtain a single phase, the preparation cost is high, and the water resistance stability / humidity resistance is poor; Eu 3+ 、Sm 3+ and Pr 3+ The narrow-band red phosphor activated by trivalent rare earth ions represented by Cr has a characteristic ff transition as a forbidden transition. The phosphor is mainly excited by ultraviolet light, has weak absorption in the blue light region, and its emission spectrum has a poor match with the plant absorption spectrum. 3+ The activated near-infrared phosphor has low absorption efficiency and Cr 3+ The valence state is unstable, and some Cr 3+ Easily reduced to Cr 4+ , the luminous efficiency needs to be further improved, the probability of non-radiative transition is high at high temperature, and the thermal stability is poor. In summary, several types of red phosphors have many problems, which limit their application in plant growth.

[0005] Therefore, there is an urgent need to develop a red phosphor material that can be effectively excited by near-ultraviolet light or visible light, has a good match between the emission spectrum and the plant absorption spectrum, and has high luminous efficiency and excellent physical and chemical stability. Summary of the invention

[0006] The object of the present invention is to provide a Mn 4+ Activated deep red light emitting phosphor for plant growth and preparation method and application thereof. The luminescent material has high luminous efficiency and good water stability, can effectively absorb near-ultraviolet or blue-green light and convert it into deep red light, thereby promoting plant growth.

[0007] The Mn provided by the present invention 4+ The activated deep red light emitting phosphor for plant growth has a double perovskite structure, a monoclinic crystal system, and a space group of P21 / n. It has broadband excitation in the range of 200-550nm, emitting red and deep red light at 600-750nm, which is similar to the plant photosensitive pigment P r and P fr The absorption spectra overlap well.

[0008] To achieve the above object, the present invention adopts the following technical solution:

[0009] A Mn 4+ Activated deep red light emitting plant growth phosphor, its chemical formula is La 2-2x-z A 2x Mg(Al 1 / 2-x- z W z ,Ta 1 / 2+x )O6:yMn 4+ , wherein A is one or more combinations of Ca, Sr, and Ba, the value range of x is 0≤x≤1 / 2; the value range of y is 0<y≤0.3; preferably y=0.005-0.15; the value range of z is 0≤z≤1 / 2, preferably z=0.25; and x+z≤1 / 2.

[0010] The phosphor can be excited by near-ultraviolet and blue light at the same time, the excitation spectrum covers 200-600nm, and the main emission peak is between 600-800nm.

[0011] The Mn 4+ The method for preparing an activated deep red light emitting phosphor comprises the following steps:

[0012] 1) According to the chemical formula La 2-2x-z A 2x Mg(Al 1 / 2-x-z W z ,Ta 1 / 2+x )O6:yMn 4+ According to the stoichiometric ratio of each element in the mixture, the raw materials and flux are accurately weighed, and they are fully ground and mixed to obtain a mixture;

[0013] 2) placing the mixture obtained in step 1 in an alumina crucible, sintering it through two steps of pre-sintering and calcining, cooling it to room temperature with the furnace, grinding the product into powder, and preparing a deep red light emitting phosphor for plant growth with a double perovskite structure.

[0014] Preferably, in step 1), the raw material is one or more of oxides, hydroxides, fluorides, chlorides, carbonates, nitrates, phosphates, ammonium salts, acetates or oxalates of lanthanum, calcium, strontium, barium, magnesium, aluminum, tungsten, tantalum and manganese.

[0015] Preferably, in step 1), the flux is at least one of NH4Cl, Li2CO3, and H3BO3, and the amount of the flux added is 1 to 10 wt%.

[0016] Preferably, in step 1), the grinding time is 10-60 min.

[0017] Preferably, in step 2), the sintering atmosphere is air, and the heating rate is 5°C / min.

[0018] Preferably, in step 2), the pre-sintering temperature is 850-900°C, and the holding time is 3-6 hours. The calcining temperature is 1450-1600°C, and the holding time is 6-8 hours.

[0019] Furthermore, the present invention also provides the use of the deep red light emitting phosphor in a light conversion film for promoting plant growth.

[0020] The light conversion film for plant growth is prepared by mixing deep red light emitting fluorescent powder and polymer in a certain proportion.

[0021] Preferably, the polymer is at least one of epoxy resin (AB glue), polydimethylsiloxane (PDMS), polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), polyvinyl acetate (PVAc), polyvinyl alcohol (PVA), ethylene-vinyl acetate (EVA), polycarbonate (PC), polystyrene (PS), polyethylene terephthalate (PET), and polymethacrylate (PMMA), and the mixing ratio of the phosphor to the polymer is 1:2-100.

[0022] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0023] 1. Mn provided by the present invention 4+ The activated double perovskite structure phosphor has an emission spectrum covering the range of 600-800nm ​​under near-ultraviolet or visible light excitation, with the strongest emission peak at 706nm, which is similar to the plant photosensitive pigment P r / P fr The absorption spectra overlap well, which can effectively improve the photosynthesis rate of plants. In addition, it has excellent quantum efficiency and water stability, can be used for a long time in the humid environment required for plant growth and basically maintain the original luminous intensity, and has good application prospects in the field of plant lighting.

[0024] 2. The light conversion film provided by the present invention can use sunlight to supplement the light of stem, leaf and fruit plants, which can effectively reduce the energy consumption in the plant cultivation process, enhance the efficiency of plant photosynthesis, shorten the growth cycle, increase the yield and fruit quality, and help improve economic benefits.

[0025] 3. Mn provided by the present invention 4+ The method for preparing the activated deep red light emitting phosphor has the advantages of simple process, no need for protective atmosphere, easy synthesis, environmentally friendly production process and conducive to mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1is a comparison chart of the X-ray diffraction patterns of the phosphors synthesized in Examples 1-8 and the standard data card;

[0027] Figure 2 1 is the excitation spectrum and emission spectrum of the phosphor synthesized in Example 2;

[0028] Figure 3 The emission spectrum of the phosphor obtained in Example 3 is similar to that of the photosensitive pigment P r and P fr and a comparison of the absorption spectra of chlorophyll a / b;

[0029] Figure 4 The water stability test results of the phosphor synthesized in Example 4 under the conditions of 85°C / 85%H;

[0030] Figure 5 This is a graph of the quantum efficiency of the phosphor synthesized in Example 5;

[0031] Figure 6 is the sunlight reflection spectrum of the PP film in Example 12;

[0032] Figure 7 is the solar reflection spectrum of the PDMS film in Example 13;

[0033] Figure 8 The experimental diagram of the light conversion film promoting the growth of lettuce in Example 12 and the standard error diagram and significance analysis of dry and fresh weight;

[0034] Fig. 9 It is the experimental diagram of the light conversion film in Example 12 promoting the growth of cherry tomatoes and the standard error diagram and significance analysis of dry and fresh weight. DETAILED DESCRIPTION

[0035] The technical scheme of the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. Obviously, the embodiments are only part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by ordinary technicians in this field without creative work are within the protection scope of the present invention.

[0036] Example 1

[0037] This embodiment provides a La2Mg(Al 0.5 Ta 0.5 )O6:0.005Mn 4+The phosphor powder is prepared by the following steps: 0.6516 g of La2O3, 0.0806 g of MgO, 0.0510 g of Al2O3, 0.2209 g of Ta2O5 and 0.0011 g of MnCO3 are weighed according to the stoichiometric ratio of each element, all the raw materials and 0.03 g of NH4Cl are fully ground and mixed, and then put into an alumina crucible, and then placed in a high-temperature furnace, heated to 850°C at a heating rate of 5°C / min in an air atmosphere, pre-fired for 6 hours, and then heated to 1550°C at the same heating rate and calcined for 8 hours, and then cooled to room temperature with the furnace, and then ground to obtain La2Mg(Al2O3). 0.5 Ta 0.5 )O6:0.005Mn 4+ Phosphor.

[0038] Example 2

[0039] This embodiment provides a La 1.75 Ba 0.25 Mg(Al 0.375 Ta 0.625 )O6:0.005Mn 4+ The phosphor powder is prepared by the following steps: 0.5702 g of La2O3, 0.0987 g of BaCO3, 0.0806 g of MgO, 0.0382 g of Al2O3, 0.2762 g of Ta2O5 and 0.0011 g of MnCO3 are weighed according to the stoichiometric ratio of each element, all the raw materials and 0.03 g of NH4Cl are fully ground and mixed, and then put into an alumina crucible, and then placed in a high-temperature furnace, heated to 850°C at a heating rate of 5°C / min in an air atmosphere, pre-fired for 6 hours, and then heated to 1550°C at the same heating rate and calcined for 8 hours, and then cooled to room temperature with the furnace, and then ground to obtain La2O3. 1.75 Ba 0.25 Mg(Al 0.375 Ta 0.625 )O6:0.005Mn 4+ Phosphor.

[0040] Example 3

[0041] This embodiment provides a La 1.5 Ba 0.5 Mg(Al 0.25 Ta 0.75 )O6:0.005Mn 4+The phosphor powder is prepared by the following steps: 0.4887 g of La2O3, 0.1973 g of BaCO3, 0.0806 g of MgO, 0.0255 g of Al2O3, 0.3314 g of Ta2O5 and 0.0011 g of MnCO3 are weighed according to the stoichiometric ratio of each element, all the raw materials and 0.03 g of NH4Cl are fully ground and mixed, and then put into an alumina crucible, and then placed in a high-temperature furnace, heated to 850°C at a heating rate of 5°C / min in an air atmosphere, pre-fired for 6 hours, and then heated to 1550°C at the same heating rate and calcined for 8 hours, and then cooled to room temperature with the furnace, and then ground to obtain La2O3. 1.5 Ba 0.5 Mg(Al 0.25 Ta 0.75 )O6:0.005Mn 4+ Phosphor.

[0042] Example 4

[0043] This embodiment provides a La 1.5 Ba 0.5 Mg(W 0.25 Ta 0.75 )O6:0.005Mn 4+ The phosphor powder is prepared by the following steps: 0.4887 g of La2O3, 0.1973 g of BaCO3, 0.0806 g of MgO, 0.1249 g of H2WO4, 0.3314 g of Ta2O5 and 0.0011 g of MnCO3 are weighed according to the stoichiometric ratio of each element, all the raw materials and 0.03 g of NH4Cl are fully ground and mixed, and then put into an alumina crucible, and then placed in a high-temperature furnace, heated to 850°C at a heating rate of 5°C / min in an air atmosphere, pre-fired for 6 hours, and then heated to 1550°C at the same heating rate and calcined for 8 hours, and then cooled to room temperature with the furnace, and then ground to obtain La2O3. 1.5 Ba 0.5 Mg(W 0.25 Ta 0.75 )O6:0.005Mn 4+ Phosphor.

[0044] Example 5

[0045] This embodiment provides a La 1.25 Ba 0.5 Mg(W 0.25 Ta 0.75 )O6:0.005Mn 4+The phosphor powder is prepared by the following steps: 0.4073 g of La2O3, 0.1973 g of BaCO3, 0.0806 g of MgO, 0.1249 g of H2WO4, 0.3314 g of Ta2O5 and 0.0011 g of MnCO3 are weighed according to the stoichiometric ratio of each element, all the raw materials and 0.03 g of NH4Cl are fully ground and mixed, and then put into an alumina crucible, and then placed in a high-temperature furnace, heated to 850°C at a heating rate of 5°C / min in an air atmosphere, pre-fired for 6 hours, and then heated to 1550°C at the same heating rate and calcined for 8 hours, and then cooled to room temperature with the furnace, and then ground to obtain La2O3. 1.25 Ba 0.5 Mg(W 0.25 Ta 0.75 )O6:0.005Mn 4+ Phosphor.

[0046] Example 6

[0047] This embodiment provides a La 1.25 Sr 0.5 Mg(W 0.25 Ta 0.75 )O6:0.005Mn 4+ The phosphor powder is prepared by the following steps: 0.4073 g of La2O3, 0.1476 g of SrCO3, 0.0806 g of MgO, 0.1249 g of H2WO4, 0.3314 g of Ta2O5 and 0.0011 g of MnCO3 are weighed according to the stoichiometric ratio of each element, all the raw materials and 0.03 g of NH4Cl are fully ground and mixed, and then put into an alumina crucible, and then placed in a high-temperature furnace, heated to 850°C at a heating rate of 5°C / min in an air atmosphere, pre-fired for 6 hours, and then heated to 1550°C at the same heating rate and calcined for 8 hours, and then cooled to room temperature with the furnace, and then ground to obtain La2O3. 1.25 Sr 0.5 Mg(W 0.25 Ta 0.75 )O6:0.005Mn 4+ Phosphor.

[0048] Example 7

[0049] This embodiment provides a La 1.25 Ca 0.5 Mg(W 0.25 Ta 0.75 )O6:0.005Mn 4+The phosphor powder is prepared by the following steps: 0.4073 g of La2O3, 0.1001 g of CaCO3, 0.0806 g of MgO, 0.1249 g of H2WO4, 0.3314 g of Ta2O5 and 0.0011 g of MnCO3 are weighed according to the stoichiometric ratio of each element, all the raw materials and 0.03 g of NH4Cl are fully ground and mixed, and then put into an alumina crucible, and then placed in a high-temperature furnace, heated to 850°C at a heating rate of 5°C / min in an air atmosphere, pre-fired for 6 hours, and then heated to 1550°C at the same heating rate and calcined for 8 hours, and then cooled to room temperature with the furnace, and then ground to obtain La2O3. 1.25 Ca 0.5 Mg(W 0.25 Ta 0.75 )O6:0.005Mn 4+ Phosphor.

[0050] Example 8

[0051] This embodiment provides a La 1.75 Mg(Al 0.25 W 0.25 Ta 0.5 )O6:0.005Mn 4+ The phosphor powder is prepared by the following steps: 0.5702 g of La2O3, 0.0806 g of MgO, 0.0255 g of Al2O3, 0.1249 g of H2WO4, 0.2209 g of Ta2O5 and 0.0011 g of MnCO3 are weighed according to the stoichiometric ratio of each element, all the raw materials and 0.03 g of NH4Cl are fully ground and mixed, and then put into an alumina crucible, and then placed in a high-temperature furnace, heated to 850°C at a heating rate of 5°C / min in an air atmosphere, pre-fired for 6 hours, and then heated to 1550°C at the same heating rate and calcined for 8 hours, and then cooled to room temperature with the furnace, and then ground to obtain La2O3. 1.75 Mg(Al 0.25 W 0.25 Ta 0.5 )O6:0.005Mn 4+ Phosphor.

[0052] Example 9

[0053] Ethylene-vinyl acetate was added to the toluene solution, and dissolved under constant temperature heating and stirring at 35°C until the whole solution became viscous, to obtain an ethylene-vinyl acetate solution. The phosphor of Example 3 was mixed with ethylene-vinyl acetate at a mass ratio of 1:100 (1wt%), and spin-coated at a speed of 10000 r / min to form a film, and demolded to obtain an EVA-based light conversion film.

[0054] Example 10

[0055] The phosphor in Example 3 was mixed with epoxy resin (wherein the mixing ratio of AB glue was 3:1) at a mass ratio of 1:20 (5wt%), degassed using a vacuum degassing machine, poured into a mold and placed in a drying oven at 60°C for 2h, and demolded to obtain a light-conversion film based on an epoxy resin matrix.

[0056] Embodiment 11

[0057] Add polyvinyl alcohol to deionized water, and dissolve it under constant temperature and stirring at 95°C until the whole solution becomes viscous to obtain a polyvinyl alcohol solution. Mix the phosphor of Example 3 with polyvinyl alcohol at a mass ratio of 1:10 (10wt%), degas with a vacuum degasser, pour into a mold to cast a film, let it stand for air drying and solidification, and demold to obtain a light conversion film based on polyvinyl alcohol (PVA).

[0058] Example 12

[0059] The phosphor in Example 4 was mixed with polypropylene at a mass ratio of 3:20 (15wt%), put into an internal mixer for refining and mixing evenly, crushed, pressed by a film press, and demolded to obtain a light conversion film based on polypropylene PP.

[0060] Example 13

[0061] The phosphor of Example 3 was mixed with a polysiloxane composition (polydimethylsiloxane and octamethylcyclotetrasiloxane were mixed in a mass ratio of 9:1) in a mass ratio of 1:5 (20wt%), degassed with a vacuum degassing machine, poured into a mold and placed in a drying oven at 80°C for 10 hours, and demolded to obtain a light-conversion film based on a polysiloxane PDMS matrix.

[0062] Figure 1 The X-ray diffraction diagram of the phosphor synthesized in Example 1-8 and the comparison diagram of the standard data card are shown in the figure. As shown in the figure, all the main diffraction peaks can correspond to the standard data card one by one, which indicates that a single phase is successfully synthesized.

[0063] Figure 2 The excitation spectrum and emission spectrum of the phosphor synthesized in Example 2 are shown in the figure. As can be seen from the figure, under the monitoring wavelength of 706nm, the excitation spectrum of the phosphor covers the range of 200-600nm, and can be effectively excited by near-ultraviolet and part of visible light. Under the excitation condition of 455nm, its emission spectrum is deep red light emission in the range of 600-800nm, and the best emission peak is located near 706nm.

[0064] Figure 3 The emission spectrum of the phosphor synthesized in Example 3 is similar to that of the photosensitive pigment P r and P frAnd the absorption spectrum comparison of chlorophyll a / b. It can be seen that its emission spectrum has obvious overlap with the absorption bands of chlorophyll and photosensitive pigments in plant photosynthesis.

[0065] Figure 4 The water stability test results of the phosphor synthesized in Example 4 under the conditions of 85°C / 85% H. After 1000h of the "double 85" test, the phosphor can still maintain 98.9% of its initial luminous integrated intensity, indicating that it has excellent water stability.

[0066] Figure 5 This is a diagram of the quantum efficiency of the phosphor synthesized in Example 5. Under 370nm excitation, the sample has an IQE of 85.2%, an Abs of 73.0%, and an EQE of 62.1%, which has ultra-high internal and external quantum efficiencies.

[0067] Figure 6 and Figure 7 The solar light reflection spectra are respectively the light conversion films based on polypropylene PP prepared in Example 12 and the light conversion films based on polysiloxane PDMS prepared in Example 13. It can be seen that the light conversion effect is obvious, and the ultraviolet light and part of the visible light in the sunlight can be effectively converted into deep red light, among which the red-to-blue ratio of the light conversion film based on polysiloxane PDMS is as high as 3.96.

[0068] Figure 8 The experimental diagram of the polypropylene PP matrix light conversion film in Example 12 promoting the growth of lettuce, the standard error diagram of dry and fresh weight, and the significance analysis are shown. After data comparison and analysis, in the lettuce growth experiment, both the fresh weight and dry weight of the experimental group (T) with a polypropylene PP matrix light conversion film laid around the lettuce were significantly improved compared with the blank group (CK). In the lettuce growth experiment, the fresh weight of a single plant increased by 79.22% compared with CK, and the dry weight increased by 61.41%.

[0069] Fig. 9 The experimental diagram of the polypropylene PP-based light conversion film promoting the growth of small tomatoes in Example 12, the standard error diagram of dry and fresh weight, and the significance analysis. After calculating and analyzing the data of each group, in the mini tomato growth experiment, both the dry weight and fresh weight of the experimental group (T) were significantly improved compared with the blank group (CK). In the mini tomato growth experiment, the fresh weight of a single plant T increased by 34.57% compared with CK, and the dry weight increased by 23.21%.

[0070] The above embodiments are only used to clearly illustrate the technical solutions of the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art in the field to which the present invention belongs, any modification, equivalent substitution, combination, simplification and improvement made on the basis and within the principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A Mn 4+ Activated deep red light emitting plant growth phosphor, characterized in that, Its chemical formula is La 2-2x-z A 2x Mg(Al 1 / 2-x-z W z ,Ta 1 / 2+x )O6:yMn 4+ , wherein A is one or more combinations of Ca, Sr, and Ba, the value range of x is 0≤x≤1 / 2; the value range of y is 0<y≤0.3; the value range of z is 0≤z≤1 / 2; x+z≤1 / 2.

2. A Mn according to claim 1 4+ Activated deep red light emitting plant growth phosphor, characterized in that, The phosphor can be excited by near-ultraviolet light and blue light at the same time, the excitation spectrum covers 200-600nm, and the main emission peak is located between 600-800nm.

3. A Mn as claimed in any one of claims 1 to 2 4+ A method for preparing activated deep red light emitting phosphor for plant growth, characterized in that: The following steps are involved: S1, according to the chemical formula La 2-2x-z A 2x Mg(Al 1 / 2-x-z W z ,Ta 1 / 2+x )O6:yMn 4+ According to the stoichiometric ratio of each element in the mixture, accurately weigh the lanthanum-containing compound, the calcium-containing compound, the strontium-containing compound, the barium-containing compound, the magnesium-containing compound, the aluminum-containing compound, the tungsten-containing compound, the tantalum-containing compound and the manganese-containing compound, and fully grind and mix the weighed raw materials with the flux to obtain a mixture; S2. Place the mixture obtained in step 1 in an alumina crucible, heat it to 850-900°C at a heating rate of 5°C / min in an air atmosphere, pre-sinter it for 3-6 hours, then heat it to 1450-1600°C and calcine it for 6-8 hours, cool it to room temperature with the furnace, grind the product into powder, and prepare a deep red light emitting phosphor for plant growth.

4. A Mn according to claim 3 4+ A method for preparing activated deep red light emitting phosphor for plant growth, characterized in that: In the step S1, The lanthanum-containing compound is one or more of La2O3, a lanthanum-containing hydroxide, a lanthanum-containing nitrate or a lanthanum-containing carbonate; The calcium-containing compound is one or more of CaCO3, calcium-containing hydroxide, calcium-containing fluoride or calcium-containing oxide; The strontium-containing compound is one or more of SrCO3, strontium-containing nitrate, strontium-containing chloride or strontium-containing fluoride; The barium-containing compound is one or more of BaCO3, barium-containing chloride, barium-containing phosphate or barium-containing nitrate; The magnesium-containing compound is one or more of MgO, a magnesium-containing hydroxide or a magnesium-containing carbonate; The aluminum-containing compound is one or more of Al2O3, aluminum-containing phosphate or aluminum-containing hydroxide; The tungsten-containing compound is one or more of H2WO4, tungsten-containing oxides or tungsten-containing ammonium salts; The tantalum-containing compound is one or both of Ta2O5 and tantalum-containing hydroxide; The manganese-containing compound is one or more of MnCO3, manganese-containing acetate, manganese-containing oxalate, manganese-containing hydroxide or manganese-containing oxide. The flux is one or more of NH4Cl, Li2CO3, and H3BO3, and the amount of the flux added is 1 to 10 wt%.

5. The Mn according to claim 1 4+ Application of activated deep red light emitting phosphor for plant growth, characterized in that, The fluorescent powder is mixed with a polymer to prepare a light conversion film, which can be used to supplement light for plants under sunlight to improve photosynthesis efficiency.

6. Mn according to claim 5 4+ Application of activated deep red light emitting phosphor for plant growth, characterized in that, The polymer is one or more of epoxy resin, polydimethylsiloxane, polypropylene, polyethylene, polyvinyl chloride, polyvinyl acetate, polyvinyl alcohol, ethylene-vinyl acetate, polycarbonate, polystyrene, polyethylene terephthalate and polymethacrylate, and the mass proportion of the phosphor in the light conversion film is 1%-50%.

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