Bismuth-strontium-manganese co-doped broadband blue-red two-color fluorescent material as well as preparation method and application thereof

Abstract

The invention discloses a bismuth-strontium-manganese co-doped blue-red two-color fluorescent material, which is prepared by doping Bi < 3 + > and Sr < 2 + > ions into a La lattice site of a LaScO3 matrix, doping Mn < 4 + > ions into a Sc lattice site of the LaScO3 matrix, and doping amounts of the Mn < 4 + > ions and the Sr < 2 + > ions are the same, so that the single-phase blue-red two-color fluorescent material (La1-p-qBipSrq) (Sc1-qMnq) O3 is obtained, plt; 0.01, 0.0001 lt, 0.01, 0.0001 lt; qlt; and 0.01%. The composite material disclosed by the invention can be used as a light source for promoting plant growth in a greenhouse environment, and ultraviolet light with the wavelength ranging from 270 nm to 400 nm is adopted to excite the blue-red double-color fluorescent material (La1-p-qBipSrq) (Sc1-qMnq) O3, and meanwhile, the blue-red double-color fluorescent material efficiently emits broadband blue light with the wavelength covering 350 nm to 550 nm and broadband red light with the wavelength covering 600 nm to 750 nm.

Description

Technical Field

[0001] The present invention relates to the field of luminescent materials, and particularly to a fluorescent material that can efficiently emit broadband blue light and broadband far red light that can promote plant growth under near-ultraviolet light excitation, especially a bismuth-strontium-manganese co-doped blue-red dual-color fluorescent material, a preparation method thereof, and an application thereof. Background Art

[0002] Light is a necessary condition for plant growth. Under the action of light, plants convert light energy into bioenergy through complex physiological processes to achieve energy conversion and storage. Since plants have the characteristics of selective absorption and utilization of photons of different wavelengths, therefore, using an artificial light source that completely matches the absorption spectrum of plants to provide light energy for plant cultivation can promote plant growth and achieve high-quality and high-yield crops, which is also an important way for efficient energy utilization. For example: the industrial production of cash crops such as vegetables and flowers, and the tissue culture of plants require supplementary lighting of artificial light sources; similarly, in late autumn or winter and spring seasons, as well as on rainy, foggy, and snowy days, due to the short sunlight time, greenhouse greenhouses are severely lacking in light, and crop growth requires more artificial light source for supplementary lighting. In such scenarios, the improvement of the luminous efficiency of artificial plant light sources can achieve energy conservation and emission reduction, which is an important way to reduce the cost of plant cultivation.

[0003] Photosynthetic pigments in plant leaves are important components for photosynthesis, playing the role of absorbing, transferring, and converting light energy. Chlorophyll a, b, and carotenoids all belong to photosynthetic pigments, and their absorption spectra are mainly located in the 400-500nm broadband blue light region and the 600-750nm broadband red light region. Therefore, the most suitable light source for plant growth must be able to stably and efficiently emit blue and red dual-color light at the same time. And since plants absorb more red light than blue light, artificial light sources with a higher proportion of red light in the emission spectrum are more important for plant growth.

[0004] Currently, the widely used plant growth lamps are mainly made by two methods: the LED multi-chip combination method and the light conversion method of LED chips plus light conversion fluorescent powder. The principle of the multi-chip combination method is to assemble multiple blue and red single-color chips together to make a plant lighting light source. Although this method is simple and easy to implement, the emission spectrum of LED chips is relatively narrow, which does not match the wide absorption spectrum of plants, and the connection of multiple chips results in a complex circuit, poor heat dissipation effect, and high manufacturing cost. Another commonly used solution is to coat red fluorescent powder on blue LED chips to make plant lights, which can greatly reduce the cost of plant lighting. However, since the most important part of this plant growth lamp is the fluorescent powder that emits far red light, most of these materials use Eu 3+ 、Sm 3+Fluorescent materials doped with rare earth ions such as

[0005] Therefore, to fabricate high-performance plant growth lamps, it is necessary to design and prepare fluorescent materials with an emission spectrum that precisely matches the absorption spectrum of plants and has high luminous efficiency, that is, a luminescent material that can efficiently emit broadband fluorescence in both the 400 - 500 nm blue light region and the 600 - 750 nm red light region simultaneously.

[0006] Based on the energy level structure and luminescence characteristics of Bi 3+ ,Mn 4+ ions, when Bi 3+ ,Mn 4+ are co-doped into the same matrix and the appropriate crystal field environment is regulated, it is possible to achieve a material that simultaneously emits broadband blue light with a wavelength covering 400 - 500 nm and broadband red light with a wavelength covering 600 - 750 nm, realizing a high degree of matching between the emission spectrum and the plant absorption spectrum, providing a new idea for the development of plant growth light sources. For example, the co-doped fluorescent material CaYAlO4:Bi 3+ ,Mn 4+ can simultaneously emit blue and red dual-color light with wavelengths covering 400 - 500 nm and 600 - 700 nm under 290 nm ultraviolet light excitation (Fang Y.Y., Zhang Y.Y., Zhang Y.P., Zhang T.P., Su X., Hu J.X., Bi 3+ ,Mn 4+ / Mn 3+ co-activated phosphors for indoor plant growth and temperature sensing, Journal of Alloys and Compound, 2023, 934:168049.). Although co-doping Bi 4+ ,Mn 3+ into the CaYAlO4 matrix can excite Bi 4+ ,Mn 3+ ,Mn 4+ ions to emit light simultaneously and the emission spectrum matches well with the plant light absorption spectrum, the relatively low luminous efficiency still cannot meet the requirements for application in plant light sources. Therefore, to achieve a fluorescent material with efficient blue and red dual-color light that can be widely applied, new material development schemes need to be explored. Summary of the Invention

[0007] The object of the present invention is to overcome the deficiencies in the prior art and provide a bismuth-strontium-manganese co-doped fluorescent material capable of efficiently emitting broadband blue and red double-color light under near-ultraviolet light excitation and a preparation method thereof. The fluorescent material uses LaScO3 with a perovskite structure of ABO3 as the matrix, Bi 3+ , Mn 4+ ions as activators, and simultaneously incorporates Sr 2+ to enhance the luminescence efficiency of the material and prepare a highly luminescent fluorescent material. Near-ultraviolet light is used to simultaneously excite Bi 3+ , Mn 4+ ions to efficiently emit broadband blue and red double-color fluorescence.

[0008] The present invention is realized by the following technical solutions:

[0009] Dope Bi 3+ and Sr 2+ ions into the La lattice site of the LaScO3 matrix. At the same time, dope Mn 4+ ions into the Sc lattice site of the LaScO3 matrix to prepare a single-phase fluorescent material (La 1-p-q Bi p Sr q )(Sc 1-q Mn q )O3, and the doping amounts of Mn 4+ ions and Sr 2+ ions are the same, where 0.001 < p < 0.01 and 0.0001 < q < 0.01. Use ultraviolet light with a wavelength in the range of 270 nm - 400 nm to excite the fluorescent material (La 1-p-q Bi p Sr q )(Sc 1-q Mn q )O3. The material can simultaneously and efficiently emit broadband blue light with a wavelength covering 350 - 550 nm and broadband red light with a wavelength covering 600 - 750 nm. The emission spectrum precisely matches the absorption spectrum of plant photosynthetic pigments. Using this fluorescent material to make an LED lamp and using it as a light source for plant growth in a greenhouse environment can promote plant growth.

[0010] The material design principle for realizing the efficient emission of broadband blue and red double-color fluorescence in the 350 - 550 nm blue light region and the 600 - 750 nm red light region of the fluorescent material is as follows:

[0011] Bi 3+ ions have a ground state electron configuration of 6s 2 , and the excited state energy level is 6s 1 6p 1 . The luminescence range is generally in the green and blue light bands. The excitation wavelength of Bi 3+ ions is in the ultraviolet region and generally comes from1 S0→ 3 P1 or 1 S0→ 1 The transition of P1, Bi 3+ The blue light emitted by ions usually comes from 3 P1 to 1 The relaxation radiation of S0. Its emission spectrum is related to the crystal field environment it is in. The strength of the crystal field will cause different degrees of energy level splitting, and then the energy difference between the excited state and the ground state will be different. Therefore, the emission wavelength of Bi 3+ ions can be adjusted to be in the range of 350 - 550 nm blue-violet light by adjusting the matrix structure. On the other hand, Mn 4+ ions can stably exist in the octahedral lattice of six coordination, and are also easily affected by the surrounding crystal field environment. When Mn 4+ is in a weak crystal field environment, due to 2 T 2g → 4 A 2g transition will produce broadband emission. When Mn 4+ ions are in a strong crystal field environment, due to the spin-forbidden 2 E g → 4 A 2g transition, Mn 4+ ions will have a relatively sharp emission. In most cases, the emission spectrum of Mn 4+ is narrowband emission, and the emission spectrum can have a high degree of matching with the plant absorption spectrum. Therefore, when Bi 3+ , Mn 4+ ions enter different lattice sites of the same matrix at the same time, by regulating the appropriate crystal field environment, a material can be realized to emit blue and red dual-color light with wavelength coverage of 350 - 500 nm and wavelength coverage of 600 - 750 nm at the same time, and the emission spectrum highly matches the plant absorption spectrum, and then it can be applied to the field of plant growth light sources.

[0012] LaScO3 is a new matrix material with a perovskite structure of ABO3 type. This structure presents two different cation sites, where La 3+ ions occupy the 8-coordination site, and Sc 3+ ions occupy the 6-coordination site to form ScO6 3- octahedron. In the LaScO3 lattice, the crystal field of the 8-coordination site can induce Bi 3+ to efficiently emit blue light, while the strong crystal field environment where the 6-coordination lattice site is located is conducive to Mn 4+ ions to emit far-red light through 2 E g → 4 A 2g electronic transition. Therefore, if Bi 3+, Mn 4+ Doped into the La site and Sc site of the LaScO3 matrix respectively to prepare the fluorescent material LaScO3:Bi 3+ , Mn 4+ , through crystal field regulation, a material can simultaneously emit blue and red dual-color light efficiently in the ranges of 350 - 550 nm and 600 - 750 nm.

[0013] Furthermore, equimolar Sr 2+ and Mn 4+ ions are simultaneously doped into the LaScO3 matrix, which can compensate for the charge imbalance caused by the hetero-valent ion doping of Mn 4+ ions replacing Sc 3+ ions, reduce lattice defects. At the same time, Sr 2+ ions can also adjust the crystal field environment where Mn 4+ ions are located, and improve the light conversion efficiency of Mn 4+ emitting far-red light. And the energy transfer between Bi 3+ , Mn 4+ ions is beneficial to the increase of the luminescence efficiency of Mn 4+ , which also provides an important solution for developing highly efficient light-emitting light sources for plant growth.

[0014] The process steps for preparing the above broadband blue and red dual-color fluorescent material with the chemical formula (La 1-p-q Bi p Sr q )(Sc 1-q Mn q )O3 (where 0.001 < p < 0.01, 0.0001 < q < 0.01) are as follows:

[0015] Weigh appropriate raw material reagents La2O3, Bi2O3, SrCO3, Sc2O3 and MnO2 according to stoichiometry. After fully grinding and mixing evenly, react at 850 - 950 °C for 4 - 6 hours. After natural cooling to room temperature, ball mill for 12 hours; then place it in a muffle furnace and react at a high temperature of 1400 - 1600 °C for 5 - 7 hours. After cooling to room temperature and grinding, the blue and red dual-color fluorescent material with the chemical formula (La 1-p- q Bi p Sr q )(Sc 1-q Mn q )O3 is prepared.

[0016] The blue and red dual-color fluorescent material (La 1-p-q Bi p Sr q )(Sc 1-q Mn q)O3 is dispersed in the liquid UV glue and then coated on the surface of the ultraviolet light chip with a wavelength in the range of 270 - 400 nm. The mass ratio of the UV glue to the fluorescent material is 1:1.0 - 2.0, and the coating thickness is 130 - 200 μm. After the coating is cured, a light-converting plant growth lamp is made.

[0017] The fluorescent material (La 1-p-q Bi p Sr q )(Sc 1-q Mn q )O3 is excited by ultraviolet light with a wavelength in the range of 270 nm - 400 nm, and can efficiently emit broadband blue light covering a wavelength range of 350 - 550 nm and broadband red light covering a wavelength range of 600 - 750 nm simultaneously, serving as a light source for promoting plant growth in the greenhouse environment.

[0018] Advantages of the present invention:

[0019] The present invention provides a fluorescent material that can simultaneously emit broadband blue and red light under the excitation of ultraviolet light (wavelength in the range of 270 - 400 nm). The blue light region of the emission spectrum of the material covers 350 - 550 nm, and the red light region covers 600 - 750 nm, which matches well with the plant absorption spectrum. Moreover, the light conversion efficiency of the material can reach 42.30%. Using this material to make a plant growth lamp for supplementing light during crop growth can significantly promote the growth of crops and improve the quality and yield of crops. In addition, the broadband blue and red light fluorescent material of the present invention also has the advantage of simple preparation process. Therefore, it is suitable for large-scale production. Brief Description of the Drawings

[0020] Figure 1 : X-ray diffraction pattern of the blue and red light-emitting phosphor (La 0.993-q Bi 0.007 Sr q )(Sc 1-q Mn q )O3 (abbreviated as LSO:0.007Bi 3+ ,qSr 2+ ,qMn 4+ , q = 0, 0.0003, 0.0005, 0.001, 0.003, 0.005, 0.007).

[0021] Figure 2 : Schematic diagram of the crystal structure of the blue and red light-emitting fluorescent material (La 1-p-q Bi p Sr q )(Sc 1-q Mn q )O3.

[0022] Figure 3: The optical excitation spectrum of the phosphor (La 0.993-y Bi 0.007 Sr q )(Sc 1-q Mn q )O3 (abbreviated as LSO:0.007Bi 3+ ,qSr 2+ ,qMn 4+ , q = 0.0003, 0.0005, 0.001, 0.003, 0.005, 0.007) emitting far red light at 703 nm.

[0023] Figure 4 : The photoluminescence spectrum of the phosphor (La 0.993-q Bi 0.007 Sr q )(Sc 1-q Mn q )O3 (abbreviated as LSO:0.007Bi 3+ ,qSr 2+ ,qMn 4+ , q = 0.0003, 0.0005, 0.001, 0.003, 0.005, 0.007) excited by a 350 nm light source.

[0024] Figure 5 : The quantum yield (QY) of the phosphor (La 0.9925 Bi 0.007 Sr 0.0005 )(Sc 0.9995 Mn 0.0005 )O3 (abbreviated as LSO:0.007Bi 3+ ,0.0005Sr 2+ ,0.0005Mn 4+ ) emitting light, with the inset being a partial enlarged view in the wavelength range of 400 nm - 800 nm.

[0025] Figure 6 : The phosphor (La 0.9925 Bi 0.007 Sr 0.0005 )(Sc 0.9995 Mn 0.0005 )O3 (abbreviated as LSO:0.007Bi 3+ ,0.0005Sr 2+ ,0.0005Mn 4+ ) and (La 0.993 Bi 0.007 )(Sc 0.9995 Mn 0.0005 )O3 (abbreviated as LSO:0.007Bi 3+, 0.0005Mn 4+ ) The quantum yield (QY) of luminescence, and the inset is a partial enlarged view in the wavelength range of 380 nm - 780 nm. Detailed implementation mode

[0026] Example 1: Preparation of Sr 2+ , Bi 3+ , Mn 4+ co - doped red - blue dual - color phosphor (La 0.993- q Bi 0.007 Sr q )(Sc 1-q Mn q )O3 (abbreviated as LSO: 0.007Bi 3+ , qSr 3+ , qMn 4+ , q = 0, 0.0003, 0.0005, 0.001, 0.003, 0.005, 0.007)

[0027] Using La2O3, Bi2O3, SrCO3, Sc2O3, MnO2 as raw materials. First, pre - sinter the oxide raw materials at 600 °C for 2 hours. Then, weigh appropriate amounts of La2O3, Bi2O3, SrCO3, Sc2O3, MnO2 according to stoichiometry, fully grind and mix them evenly, react at 900 °C for 6 hours, naturally cool to room temperature, ball - mill for 12 hours, and then place them in a muffle furnace again to react at a high temperature of 1500 °C for 6 hours. After cooling to room temperature and grinding, the fluorescent material LSO: 0.007Bi 3+ , qSr 2+ , qMn 4+ , (q = 0, 0.0003, 0.0005, 0.001, 0.003, 0.005, 0.007) is prepared. Figure 1 Shown is the X - ray diffraction pattern of the fluorescent material LSO: 0.007Bi 3+ , qSr 2+ , qMn 4+ , (q = 0, 0.0003, 0.0005, 0.001, 0.003, 0.005, 0.007), which proves that this Sr 2+ , Bi 3+ , Mn 4+ co - doped fluorescent material has a perovskite - type crystal structure of ABO3 type (as Figure 2 shown), belonging to the orthorhombic system, and the space group is Pbnm.

[0028] Figure 3It is shown that an excitation light source with a wavelength in the range of 250 - 450 nm can excite the material to emit far - red light with a wavelength of 703 nm. Moreover, when the wavelength of the excitation light is near 350 nm, the photo - excitation intensity reaches the maximum; the light wavelength corresponding to the maximum excitation intensity changes with the Sr 2+ doping amount, indicating that Sr 2+ doping, in addition to compensating for the charge imbalance caused by the substitution of Mn 4+ ions for Sc 3+ ions due to hetero - valent ion doping and reducing lattice defects, at the same time, Sr 2+ ions also regulate the crystal - field environment where Mn 4+ ions are located, and improve the light - conversion efficiency of Mn 4+ emitting far - red light. As Figure 4 shown, ultraviolet light with a wavelength of 350 nm can simultaneously excite Bi 3+ and Mn 4+ to emit broadband blue light with an emission wavelength covering 350 - 550 nm and broadband red light with an emission wavelength covering 600 - 750 nm respectively. Therefore, the emission spectrum of the fluorescent material LSO:0.007Bi 3+ ,qSr 3+ ,qMn 4+ , (q = 0.0003, 0.0005, 0.001, 0.003, 0.005, 0.007) precisely matches the absorption spectrum of plant photosynthetic pigments. Figure 5 It is shown that when the fluorescent material LSO:0.007Bi 3+ ,0.0005Sr 3+ ,0.0005Mn 4+ is excited by ultraviolet light with a wavelength of 350 nm, the light - conversion efficiency of emitting blue - red dual - color fluorescence can reach 42.30%, indicating that this highly efficient - emitting fluorescent material can be applied to plant light sources.

[0029] Example 2: Preparation of Sr 2+ , Bi 3+ , Mn 4+ co - doped red - blue dual - color fluorescent powder (La 0.9965 Bi 0.003 Sr 0.0005 )(Sc 0.9995 Mn 0.0005 )O3 (abbreviated as LSO:0.003Bi 3+ ,0.0005Sr 3+ ,0.0005Mn 4+ )

[0030] Using La2O3, Bi2O3, SrCO3, Sc2O3, and MnO2 as raw materials, first, the oxide raw materials are pre-fired at 600 °C for 2 hours. Then, appropriate amounts of La2O3, Bi2O3, SrCO3, Sc2O3, and MnO2 are weighed according to stoichiometry. After being thoroughly ground and mixed evenly, they are reacted at 900 °C for 6 hours. After natural cooling to room temperature, they are ball-milled for 12 hours, and then placed in a muffle furnace again to react at a high temperature of 1500 °C for 6 hours. After cooling to room temperature and grinding, the single-phase fluorescent material LSO:0.003Bi 3+ ,0.0005Sr 3+ ,0.0005Mn 4+ is obtained.

[0031] Example 3: Preparation and photoconversion efficiency of Bi 3+ , Mn 4+ co-doped red and blue double-color fluorescent powder (La 0.993 Bi 0.007 )(Sc 0.9995 Mn 0.0005 )O3 (abbreviated as LSO:0.007Bi 3+ ,0.0005Mn 4+ )

[0032] Using La2O3, Bi2O3, Sc2O3, and MnO2 as raw materials, first, the oxide raw materials are pre-fired at 600 °C for 2 hours. Then, appropriate amounts of La2O3, Bi2O3, Sc2O3, and MnO2 are weighed according to stoichiometry. After being thoroughly ground and mixed evenly, they are reacted at 900 °C for 6 hours. After natural cooling to room temperature, they are ball-milled for 12 hours, and then placed in a muffle furnace again to react at a high temperature of 1500 °C for 6 hours. After cooling to room temperature and grinding, the single-phase fluorescent material LSO:0.007Bi 3+ ,0.0005Mn 4+ is obtained.

[0033] Figure 6 It is shown that when the fluorescent material LSO:0.007Bi 3+ ,0.0005Mn 4+ is excited by ultraviolet light at 328 nm, it also emits broadband blue and red double-color light in two spectral regions of 350 - 550 nm and 600 - 750 nm. However, its photoconversion efficiency is much smaller than that of the Sr 2+ , Bi 3 + , Mn 4+ co-doped red and blue double-color fluorescent powder LSO:0.007Bi 3+ ,0.0005Sr 2+ ,0.0005Mn 4+ , indicating that Sr 2+The effect of doping on improving the luminescence efficiency of materials.

[0034] Example 4: Fabricate an LED lamp based on the fluorescent material (La 0.9925 Bi 0.007 Sr 0.0005 )(Sc 0.9995 Mn 0.0005 )O3

[0035] Disperse the fluorescent material (La 0.9925 Bi 0.007 Sr 0.0005 )(Sc 0.9995 Mn 0.0005 )O3 prepared in Example 1 above in liquid UV glue to make a slurry. The mass ratio of UV glue to fluorescent material is 1:1.5. Directly coat the glue slurry on the surface of a 365 nm chip. The chip working voltage is 4 V, the power is 2 W, the coating thickness is 150 μm. After the coating is cured, a light-converting LED plant growth lamp is fabricated.

[0036] Example 5: Application of an LED lamp based on the photoluminescence of the material (La 0.9925 Bi 0.007 Sr 0.0005 )(Sc 0.9995 Mn 0.0005 )O3 for plant growth supplementary lighting

[0037] After driving the LED lamp fabricated in Example 2 with a 250 mA current and lighting it, irradiate hydroponic garlic at night and observe the growth of garlic seedlings. Divide the garlic into a lighting group and a control group, with 7 cloves in each group. The lighting group is supplemented with light for 8 hours every night using 15 lamp beads, and the control group is not supplemented with light and grows naturally. It can be observed that the garlic seedlings in the lighting group have well-developed root hairs and grow faster and better, indicating the promoting effect of LED plant growth lamp supplementary lighting on garlic growth.

Claims

1. A bismuth, strontium, and manganese co-doped blue and red dual-color fluorescent material, characterized in that, Dope Bi 3+ and Sr 2+ ions into the La lattice sites of the LaScO3 matrix. At the same time, dope Mn 4+ ions into the Sc lattice sites of the LaScO3 matrix, and the doping amounts of Mn 4+ ions and Sr 2+ ions are the same, to obtain a single-phase blue-red dual-color fluorescent material (La 1-p-q Bi p Sr q )(Sc 1-q Mn q )O3, where: 0.001 < p < 0.01, 0.0001 < q < 0.

01.

2. The blue and red dual-color fluorescent material according to claim 1, wherein: p = 0.003 and q = 0.0005.

3. A preparation method of a bismuth strontium manganese co-doped blue and red dual-color fluorescent material according to claim 1 or 2, characterized in that, It includes the following steps: (1) Weigh appropriate raw material reagents La2O3, Bi2O3, SrCO3, Sc2O3 and MnO2 according to stoichiometry. After fully grinding and mixing evenly, heat them until the reaction is complete, then cool to room temperature and perform ball milling. (2) After reacting at high temperature in a muffle furnace and then cooling to room temperature and grinding, a blue-red dual-color fluorescent material with the chemical formula (La 1-p-q Bi p Sr q )(Sc 1-q Mn q )O3 is prepared.

4. The preparation method according to claim 3, wherein: The full heating reaction means reacting at 850 - 950 °C for 4 - 6 hours.

5. The preparation method according to claim 3, wherein: The reaction at high temperature in the muffle furnace means reacting at 1400 - 1600 °C for 5 - 7 hours.

6. An LED plant growth lamp using the bismuth, strontium and manganese co-doped blue and red dual-color fluorescent material according to claim 1 or 2, wherein: Disperse the blue-red dual-color fluorescent material (La 1-p-q Bi p Sr q )(Sc 1-q Mn q )O3 in a liquid UV glue, and then coat it on the surface of an ultraviolet light chip with a wavelength in the range of 270 - 400 nm. The mass ratio of the UV glue to the fluorescent material is 1:1.0 - 2.0, the coating thickness is 130 - 200 μm, and a light-converting plant growth lamp is made after the coating is cured.

7. A light source using the bismuth, strontium and manganese co-doped blue and red dual-color fluorescent material according to claim 1 or 2 for promoting plant growth in a greenhouse environment, wherein: The ultraviolet light with a wavelength in the range of 270 nm - 400 nm is used to excite the fluorescent material (La 1-p-q Bi p Sr q )(Sc 1-q Mn q )O3, which can simultaneously emit broadband blue light with a wavelength covering 350 - 550 nm and broadband red light with a wavelength covering 600 - 750 nm efficiently.

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