A gallate-based blue light-emitting material, a preparation method and application thereof

Abstract

The application discloses a gallate-based blue light-emitting material applicable to a plant light supplement lamp, a preparation method and application of the gallate-based blue light-emitting material, and a chemical general formula of the light-emitting material is Ca 1‑x Ga4O7:xCd 2+ , wherein x is 0.003-0.007. The gallate-based blue light-emitting material takes CaGa4O7 as a matrix, Cd 2+ is a doping ion, Cd 2+ cannot form a new light-emitting center in CaGa4O7, and only plays a role in enhancing blue light emission of the matrix. The light-emitting material produces a wide peak with a peak value of 445 nm under ultraviolet excitation, generates blue-white emission, and the emission band is highly coincident with a band required by plant growth, so that chlorophyll synthesis can be promoted, stem and leaf growth of plants is beneficial, the plant light supplement demand can be met, and the optimal afterglow duration can reach nearly 2 hours. The light supplement can still be carried out after stopping excitation, and energy consumption is reduced.

Description

Technical Field

[0001] This invention relates to the field of luminescent materials, and more particularly to a gallium-based blue luminescent material, its preparation method, and its applications. Background Technology

[0002] With economic development and improved living standards, greenhouse cultivation of off-season fruits, vegetables, and flowers has gained popularity among consumers. However, sunlight is crucial for plant growth. Insufficient sunlight intensity and duration during winter and spring severely limit crop growth, even leading to fruit drop and crop wilting, significantly impacting farmland yield and causing economic losses. Therefore, supplemental lighting for plants is essential.

[0003] Plant supplemental lighting primarily utilizes blue and red light. Currently, common plant supplemental lighting lamps include high-pressure sodium lamps, LED lamps, and fluorescent lamps. Among these, fluorescent lamps are a key research focus. Commonly used supplemental lighting fluorescent materials require continuous ultraviolet excitation to emit blue light, while long-afterglow fluorescent materials can continue to emit light even after excitation ceases. Utilizing this characteristic can save resources and reduce energy consumption. However, currently available blue long-afterglow phosphors for supplemental lighting are mainly aluminate-doped lanthanide ions, and mostly Eu... 2+ The primary doping method requires the synthesis of materials under a reducing atmosphere, resulting in stringent preparation conditions and high production costs. Therefore, it is essential to find an alternative to lanthanide-doped blue long-afterglow fluorescent materials that do not require a reducing atmosphere. Summary of the Invention

[0004] The main objective of this invention is to provide a gallium-based blue luminescent material applicable to plant supplemental lighting, its preparation method, and its application.

[0005] To achieve the above objectives, the present invention provides a gallium-based blue luminescent material with the general chemical formula Ca. 1- x Ga4O7:xCd 2+ , where x is 0.003 to 0.007.

[0006] Furthermore, the luminescent material uses the compound CaGa4O7 as a matrix and Cd ions as the luminescent material. 2+ It is a dopant.

[0007] The present invention also provides the application of the above-mentioned gallium-based blue luminescent material in the preparation of plant supplemental lighting.

[0008] This invention also provides a method for preparing the above-mentioned gallium-based blue luminescent material, comprising the following steps:

[0009] (1) Weigh the calcium source, gallium source and cadmium source according to the molar ratio of the chemical formula of the luminescent materials, grind them evenly to obtain a mixture;

[0010] (2) The mixture is transferred to an alumina crucible for high-temperature sintering, cooled to room temperature, and then ground evenly to obtain the gallium-based blue luminescent material.

[0011] Furthermore, in step (1), the calcium source is calcium carbonate, the gallium source is gallium oxide, and the cadmium source is cadmium oxide.

[0012] Furthermore, in step (2), the specific process of high-temperature sintering is as follows: the temperature is raised to 1300℃ at a heating rate of 5℃ / min, and sintered at 1300℃ for 5 hours.

[0013] The beneficial effects of this invention are reflected in:

[0014] (1) The gallium-based blue luminescent material of this invention uses CaGa4O7 as the matrix and Cd 2+ Cd is a doped ion. 2+ No new luminescent centers are formed in CaGa4O7; the luminescent material only enhances the blue light emission of the matrix. Under ultraviolet excitation, the luminescent material of this invention produces a broad peak at 445nm, generating blue-white emission. Compared with CaGa4O7 as the matrix, the luminescence intensity is greatly improved. This emission band highly overlaps with the band required for plant growth, which can promote chlorophyll synthesis, benefit the growth of plant stems and leaves, and meet the supplemental lighting needs of plants.

[0015] (2) The gallium-based blue luminescent material of the present invention exhibits excellent afterglow brightness and duration after being fully excited by a 254nm ultraviolet lamp. The optimal afterglow duration can reach nearly 2 hours. It can still provide supplemental light after the excitation stops, thus reducing energy consumption.

[0016] (2) The gallium-based blue luminescent material of the present invention uses the transition metal ion Cd 2+ This invention replaces rare-earth ion doping, achieving high-efficiency emission at a lower cost. The luminescent material is prepared using a high-temperature solid-state method, which can be synthesized in an air atmosphere, resulting in a simple process with low requirements for production equipment. Attached Figure Description

[0017] Figure 1 The Ca prepared in Examples 1 to 5 and Comparative Example 1 of this invention 1-x Ga4O7:xCd 2+ XRD patterns of luminescent materials and CaGa4O7 standard cards;

[0018] Figure 2 The excitation and emission spectra of the gallium-based blue luminescent materials prepared in Examples 1 to 5 and Comparative Example 1 of this invention, which can be applied to plant supplemental lighting;

[0019] Figure 3The afterglow decay curves of the gallate-based blue luminescent materials prepared in Examples 1 to 5 of this invention, which can be applied to plant supplemental lighting. Detailed Implementation

[0020] To enable those skilled in the art to more clearly understand the technical solutions described in this invention, the following embodiments are provided for illustration. It should be noted that the following embodiments do not constitute a limitation on the scope of protection claimed by this invention.

[0021] Unless otherwise specified, the raw materials, reagents or devices used in the following examples are available from conventional commercial sources or can be obtained by existing known methods.

[0022] Example 1

[0023] Preparation of gallium-based blue luminescent materials

[0024] The chemical formula of the gallium-based blue luminescent material prepared in this embodiment is: Ca 0.997 Ga4O7:0.003Cd 2+ The specific preparation process is as follows:

[0025] Weigh out CaCO3, Ga2O3, and CdO raw materials according to a molar ratio of 0.997:2:0.003, place them in an agate mortar, add ethanol (the amount of ethanol added is just enough to wet the raw materials, the same below), and grind for 30 minutes to obtain a uniformly mixed powder. Transfer the mixture to an alumina crucible, and heat it to 1300℃ in a muffle furnace under air atmosphere at a heating rate of 5℃ / min, and sinter it at 1300℃ for 5 hours. After the system cools to room temperature, grind the obtained product into powder to obtain CaCO3. 0.997 Ga4O7:0.003Cd 2+ Luminescent materials.

[0026] Depend on Figure 1 The XRD patterns shown indicate that the Ca prepared in this example... 0.997 Ga4O7:0.003Cd 2+ The luminescent material showed good compatibility with the standard card, and no impurity peaks were observed, indicating that the obtained luminescent material was a pure phase.

[0027] Depend on Figure 2 As shown in the excitation and emission spectra, the luminescent material prepared in this example produces a broad emission peak of 320nm-650nm after being excited by 261nm ultraviolet light, with the peak value located at 445nm.

[0028] Depend on Figure 3 As shown in the afterglow decay curve, the afterglow brightness of the luminescent material prepared in this example is 87.79 mcd / m² after 10 seconds. 2The lowest luminance perceptible to the human eye is 0.32 mcd / m². 2 The afterglow intensity of the luminescent material remained at 0.32 mcd / m 2 The above duration is 1 hour and 4 minutes.

[0029] Example 2

[0030] Preparation of gallium-based blue luminescent materials

[0031] The chemical formula of the gallium-based blue luminescent material prepared in this embodiment is: Ca 0.996 Ga4O7:0.004Cd 2+ The specific preparation process is as follows:

[0032] CaCO3, Ga2O3, and CdO raw materials were weighed according to a molar ratio of 0.996:2:0.004, placed in an agate mortar, and ground with ethanol for 30 minutes to obtain a uniformly mixed powder. The mixture was transferred to an alumina crucible and heated to 1300℃ in a muffle furnace under air atmosphere at a heating rate of 5℃ / min, and sintered at 1300℃ for 5 hours. After the system cooled to room temperature, the resulting product was ground into powder to obtain CaCO3. 0.996 Ga4O7:0.004Cd 2+ Luminescent materials.

[0033] Depend on Figure 1 The XRD patterns shown indicate that the Ca prepared in this example... 0.996 Ga4O7:0.004Cd 2+ The luminescent material showed good compatibility with the standard card, and no impurity peaks were observed, indicating that the obtained luminescent material was a pure phase.

[0034] Depend on Figure 2 As shown in the excitation and emission spectra, the luminescent material prepared in this example produces a broad emission peak of 320nm-650nm after being excited by 261nm ultraviolet light, with the peak value located at 445nm.

[0035] Depend on Figure 3 As shown in the afterglow decay curve, the afterglow brightness of the luminescent material prepared in this example is 20.59 mcd / m² after 10 seconds. 2 The lowest luminance perceptible to the human eye is 0.32 mcd / m². 2 The afterglow intensity of the luminescent material remained at 0.32 mcd / m 2 The above duration is 1 hour and 52 minutes.

[0036] Example 3

[0037] Preparation of gallium-based blue luminescent materials

[0038] The chemical formula of the gallium-based blue luminescent material prepared in this embodiment is: Ca 0.995 Ga4O7:0.005Cd 2+ The specific preparation process is as follows:

[0039] CaCO3, Ga2O3, and CdO raw materials were weighed according to a molar ratio of 0.995:2:0.005, placed in an agate mortar, and ground with ethanol for 30 minutes to obtain a uniformly mixed powder. The mixture was transferred to an alumina crucible and heated to 1300℃ in a muffle furnace under air atmosphere at a heating rate of 5℃ / min, and sintered at 1300℃ for 5 hours. After the system cooled to room temperature, the resulting product was ground into powder to obtain CaCO3. 0.995 Ga4O7:0.005Cd 2+ Luminescent materials.

[0040] Depend on Figure 1 The XRD patterns shown indicate that the Ca prepared in this example... 0.995 Ga4O7:0.005Cd 2+ The luminescent material showed good compatibility with the standard card, and no impurity peaks were observed, indicating that the obtained luminescent material was a pure phase.

[0041] Depend on Figure 2 As shown in the excitation and emission spectra, the luminescent material prepared in this example produces a broad emission peak of 320nm-650nm after being excited by 261nm ultraviolet light, with the peak value located at 445nm.

[0042] Depend on Figure 3 As shown in the afterglow decay curve, the afterglow brightness of the luminescent material prepared in this example is 9.83 mcd / m² after 10 seconds. 2 The lowest luminance perceptible to the human eye is 0.32 mcd / m². 2 The afterglow intensity of the luminescent material remained at 0.32 mcd / m 2 The above duration is 38 minutes.

[0043] Example 4

[0044] Preparation of gallium-based blue luminescent materials

[0045] The chemical formula of the gallium-based blue luminescent material prepared in this embodiment is: Ca 0.994 Ga4O7:0.006Cd 2+ The specific preparation process is as follows:

[0046] CaCO3, Ga2O3, and CdO raw materials were weighed according to a molar ratio of 0.994:2:0.006, placed in an agate mortar, and ground with ethanol for 30 minutes to obtain a uniformly mixed powder. The mixture was transferred to an alumina crucible and heated to 1300℃ in a muffle furnace under air atmosphere at a heating rate of 5℃ / min, and sintered at 1300℃ for 5 hours. After the system cooled to room temperature, the resulting product was ground into powder to obtain CaCO3. 0.994 Ga4O7:0.006Cd 2+ Luminescent materials.

[0047] Depend on Figure 1 The XRD patterns shown indicate that the Ca prepared in this example... 0.994 Ga4O7:0.006Cd 2+ The luminescent material showed good compatibility with the standard card, and no impurity peaks were observed, indicating that the obtained luminescent material was a pure phase.

[0048] Depend on Figure 2 As shown in the excitation and emission spectra, the luminescent material prepared in this example produces a broad emission peak of 320nm-650nm after being excited by 261nm ultraviolet light, with the peak value located at 445nm.

[0049] Depend on Figure 3 As shown in the afterglow decay curve, the afterglow brightness of the luminescent material prepared in this example is 8.48 mcd / m² after 10 seconds. 2 The lowest luminance perceptible to the human eye is 0.32 mcd / m². 2 The afterglow intensity of the luminescent material remained at 0.32 mcd / m 2 The above duration is 33 minutes.

[0050] Example 5

[0051] Preparation of gallium-based blue luminescent materials

[0052] The chemical formula of the gallium-based blue luminescent material prepared in this embodiment is: Ca 0.993 Ga4O7:0.007Cd 2+ The specific preparation process is as follows:

[0053] CaCO3, Ga2O3, and CdO raw materials were weighed according to a molar ratio of 0.993:2:0.007, placed in an agate mortar, and ground with ethanol for 30 minutes to obtain a uniformly mixed powder. The mixture was transferred to an alumina crucible and heated to 1300℃ in a muffle furnace under air atmosphere at a heating rate of 5℃ / min, and sintered at 1300℃ for 5 hours. After the system cooled to room temperature, the resulting product was ground into powder to obtain CaCO3. 0.993Ga4O7:0.007Cd 2+ Luminescent materials.

[0054] Depend on Figure 1 The XRD patterns shown indicate that the Ca prepared in this example... 0.993 Ga4O7:0.007Cd 2+ The luminescent material showed good compatibility with the standard card, and no impurity peaks were observed, indicating that the obtained luminescent material was a pure phase.

[0055] Depend on Figure 2 As shown in the excitation and emission spectra, the luminescent material prepared in this example produces a broad emission peak of 320nm-650nm after being excited by 261nm ultraviolet light, with the peak value located at 445nm.

[0056] Depend on Figure 3 As shown in the afterglow decay curve, the afterglow brightness of the luminescent material prepared in this example is 7.01 mcd / m² after 10 seconds. 2 The lowest luminance perceptible to the human eye is 0.32 mcd / m². 2 The afterglow intensity of the luminescent material remained at 0.32 mcd / m 2 The duration of the above is 16 minutes.

[0057] Comparative Example 1

[0058] Preparation of CaGa4O7 luminescent materials

[0059] Based on Example 1, the doping of CdO is omitted, and only CaCO3 and Ga2O3 are weighed in a molar ratio of 1:2, while the other steps and conditions are the same.

[0060] Depend on Figure 1 The XRD pattern shown indicates that the CaGa4O7 luminescent material prepared in this comparative example has a good fit with the standard card, and no impurity peaks were observed, indicating that the obtained luminescent material is a pure phase.

[0061] Depend on Figure 2 The excitation and emission spectra shown indicate that the luminescent material prepared in this comparative example, when excited by 261nm ultraviolet light, produces a broad emission peak of 320nm-650nm, with the peak value located at 445nm. Compared with the aforementioned embodiments, it can be seen that the excitation and emission peaks do not show any change in peak shape, indicating that Cd doping does not act as a new luminescent center, but only enhances the blue light emission of the matrix, and can be applied to supplemental lighting for plants.

[0062] Depend on Figure 3 As shown in the afterglow decay curve, the afterglow brightness of the luminescent material prepared in this example is 1.39 mcd / m² after 10 seconds. 2 The lowest luminance perceptible to the human eye is 0.32 mcd / m². 2The afterglow intensity of the luminescent material remained at 0.32 mcd / m 2 The above duration is 6 minutes.

[0063] Results analysis:

[0064] Figure 1 The XRD patterns of Examples 1 to 5 and Comparative Example 1 are shown. It can be seen that Ca... 1-x Ga4O7:xCd 2+ The series of luminescent materials correspond well to the CaGa4O7 standard card, with no impurity peaks, indicating that the above preparation method can obtain Ca... 1-x Ga4O7:xCd 2+ Pure phase.

[0065] Figure 2 The excitation and emission spectra of Examples 1 to 5 and Comparative Example 1 are shown, and it can be seen that Ca 1-x Ga4O7:xCd 2+ The emission intensity of the luminescent material increases with the increase of Cd doping amount, reaching the maximum luminescence intensity when x = 0.006, and then the intensity decreases. Compared with the comparative example, the maximum intensity is increased by nearly 6 times.

[0066] Figure 3 The afterglow decay curves of Examples 1 to 5 and Comparative Example 1 are shown. It can be seen that Ca... 1-x Ga4O7:xCd 2+ The afterglow duration of the series of luminescent materials first increases and then decreases with the increase of Cd doping amount. The afterglow time is the longest when x = 0.004, reaching 1 hour and 52 minutes. Compared with the comparative example, the maximum afterglow time is increased by nearly 19 times.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A gallium-based blue luminescent material, characterized in that, Its general chemical formula is Ca 1-x Ga4O7:xCd 2+ Where x is 0.003 to 0.007; the luminescent material uses the compound CaGa4O7 as a matrix and Cd ions as the luminescent material. 2+ It is a dopant.

2. The application of the gallium-based blue luminescent material as described in claim 1 in the preparation of plant supplemental lighting.

3. The method for preparing gallium-based blue luminescent material as described in claim 1, characterized in that, Includes the following steps: (1) Weigh the calcium source, gallium source and cadmium source according to the molar ratio of the chemical formula of the luminescent materials, grind them evenly to obtain a mixture; (2) The mixture is transferred to an alumina crucible for high-temperature sintering, cooled to room temperature, and then ground evenly to obtain the gallium-based blue luminescent material.

4. The method for preparing the gallium-based blue luminescent material as described in claim 3, characterized in that, In step (1), the calcium source is calcium carbonate, the gallium source is gallium oxide, and the cadmium source is cadmium oxide.

5. The method for preparing the gallium-based blue luminescent material as described in claim 3, characterized in that, In step (2), the specific process of high-temperature sintering is as follows: the temperature is raised to 1300℃ at a heating rate of 5℃ / min, and sintered at 1300℃ for 5 h.

Images