Non-sulfur red long afterglow fluorescent powder, and preparation method and application thereof

Abstract

The application provides a non-sulfur red long-afterglow fluorescent powder, a preparation method and application thereof. 1‑y Ti 1‑x O3: xPr 4+ , yTm 3+ , wherein M is any one of Ba, Sr, Ca or Mg, x and y represent molar fractions, wherein 0.0005 <= x <= 0.003, 0.01 <= y <= 0.2. Carbonates or oxides of M, oxides of Ti, Pr and Tm are mixed according to the stoichiometry of the chemical formula of the red long-afterglow fluorescent powder, a fluxing agent is added for sintering, the sintered product is crushed and then ball milled, and the non-sulfur red long-afterglow fluorescent powder is obtained. The red long-afterglow fluorescent powder has stronger water resistance and longer afterglow duration. Raw materials are easy to obtain and have a low price, the system can be prepared by using a traditional high-temperature solid-phase method, and no sulfidation agent or sulfur element is needed in the preparation process, so that commercialization cost is low, safety is higher, and risk treatment cost is low.

Description

Technical Field

[0001] This application belongs to the field of inorganic luminescent materials technology, and in particular relates to a non-sulfur red long afterglow phosphor, its preparation method and application. Background Technology

[0002] Long-afterglow phosphors can store excitation energy by absorbing ultraviolet or visible light. After the excitation source is removed, the energy is gradually released by emitting visible light at room temperature, ranging from a few seconds to several hours. This phenomenon, caused by the migration and recombination of charge carriers (electrons and / or holes), has attracted considerable attention in recent years. These phosphors are widely used as night vision materials in various important fields, such as security signs, emergency route signs, traffic signs, decoration, displays, energy, and live bio-imaging.

[0003] To date, relatively mature tri-color long-afterglow phosphors generally include: green phosphor SrAl2O4:Eu 2+ ,Dy 3+ Blue phosphor CaAl2O4:Eu 2+ ,Nd 3+ And red fluorescent powder Y2O2S:Eu 3+ Mg 2+ Ti 4+ Compared to green and blue long-afterglow phosphors, the red long-afterglow phosphor Y₂O₂S:Eu 3+ Ti 4+ Mg 2+ There are two main problems: First, the duration of visible light is short (<5h); second, the main component Y2O2S is unstable and particularly sensitive to moisture, and the use of sulfiding agents or elemental sulfur in the material preparation process poses a significant hazard to workers and the surrounding environment, and addressing this risk requires high costs.

[0004] For red long-afterglow phosphors, universities, research institutes, and phosphor manufacturers have successively developed non-sulfur-based red long-afterglow phosphor materials such as germanates, borates, and titanates, for example, Ca4LaO(BO3)3:Eu 3+ SrGa2O4:Cu 2 + NaCa2GeO4F:Mn 2+ ,Yb 3+ Ca2Zn4Ti 16 O 38 :Pr 3+However, these long-afterglow phosphors still have the following problems: 1. The preparation of borates requires a co-precipitation method, which raises waste liquid treatment issues; 2. Germanates require germanium oxide as a raw material, which is expensive and results in high raw material costs; 3. Gallate and titanate systems have low afterglow brightness; 4. Samples sintered using traditional high-temperature solid-state methods are not uniform. These problems hinder their commercial production. Summary of the Invention

[0005] This application provides a non-sulfur red long-afterglow phosphor, its preparation method, and its application to solve the problems existing in related technologies. The technical solution is as follows: In one aspect, embodiments of this application provide a non-sulfur red long-afterglow phosphor, the chemical formula of which is M. 1-y Ti 1-x O3: xPr 4+ yTm 3+ , where M is any one of Ba, Sr, Ca or Mg, and x and y represent mole fractions, where 0.0005≤x≤0.003 and 0.01≤y≤0.2.

[0006] Secondly, embodiments of this application provide a method for preparing the aforementioned non-sulfur red long-afterglow phosphor, characterized by comprising the following steps: Mix the carbonate or oxide of M, and the oxides of Ti, Pr and Tm according to the stoichiometry of the chemical formula of the red long afterglow phosphor. A flux was added and sintering was carried out; the sintered product was crushed and then ball-milled to obtain the non-sulfur red long afterglow phosphor.

[0007] In one embodiment, the carbonate or oxide of M is BaCO3, SrCO3, CaCO3, or MgO; and the oxides of Ti, Pr, and Tm are TiO2, Pr6O, etc. 11 And Tm2O3.

[0008] In one embodiment, the flux is a mixture of AlF3 and H3BO3; the amount of flux added is 8-16% of the weight of the raw materials.

[0009] In one embodiment, the ratio of AlF3 to H3BO3 is 1:(5-15).

[0010] In one embodiment, the particle size of AlF3 is 180–220 mesh; the particle size of H3BO3 is 80–110 mesh.

[0011] In one embodiment, sintering is divided into staged sintering. The first sintering is carried out at 350-450°C in an oxygen atmosphere for 1-3 hours; the second sintering is carried out at 1200-1400°C in an oxygen atmosphere for 3-5 hours.

[0012] In one implementation, the ball mill uses water as the medium; During the ball milling process, the mass ratio of phosphor, water and milling balls is 1:(1.5~1.9):(2~2.5); the ball milling time is 2~5h.

[0013] In one embodiment, the ball-milled slurry is sieved, separated from its solids, and dried to obtain the non-sulfur red long afterglow phosphor.

[0014] In one embodiment, the sieve is a 200-mesh sieve; the solid-liquid separation is carried out by vacuum filtration; the drying temperature is 100-130°C, and the drying time is 8-24 hours.

[0015] In one embodiment, after the raw materials are mixed, they are dispersed by sieving and then mixed again until uniform.

[0016] Thirdly, embodiments of this application provide an application of a non-sulfur red long-afterglow phosphor in light-emitting or lighting devices.

[0017] The advantages or beneficial effects of the above technical solutions include at least the following: The red long-afterglow phosphor in this application is M. 1-y Ti 1-x O3: xPr 4+ yTm 3+ M is any one of Ba, Sr, Ca, or Mg; the red long-afterglow phosphor of this application has stronger water resistance and a longer afterglow duration. The matrix raw materials used are oxides or carbonates of barium (or strontium, calcium, magnesium) and oxides of titanium, and the activator raw material is praseodymium oxide. The raw materials are readily available and inexpensive, and the system can be prepared using the traditional high-temperature solid-state method, resulting in low commercialization costs. Moreover, no sulfiding agent or elemental sulfur is required during the preparation process, leading to higher safety and lower risk management costs.

[0018] The above overview is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features of this application will become readily apparent from the accompanying drawings and the following detailed description. Attached Figure Description

[0019] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the various drawings denote the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings depict only some embodiments disclosed in this application and should not be construed as limiting the scope of this application.

[0020] Figure 1 SEM image of the non-sulfur red long-afterglow phosphor prepared in Example 3; Figure 2 The emission spectrum of the non-sulfur red long-afterglow phosphor prepared in Example 3 is shown. Detailed Implementation

[0021] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of this application. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0022] Currently, the most commercially viable red phosphor is Y₂O₂S:Eu. 3+ Red long-afterglow phosphors suffer from poor stability, and their preparation process involves the use of sulfiding agents or elemental sulfur, posing significant safety risks. Non-sulfur-based red long-afterglow phosphors, on the other hand, suffer from low afterglow brightness, uneven sample formation during traditional high-temperature solid-state sintering, and high raw material costs. Therefore, this application provides a non-sulfur-based red long-afterglow phosphor, its preparation method, and its applications.

[0023] A non-sulfur red long-afterglow phosphor, the chemical formula of which is M 1-y Ti 1-x O3: xPr 4+ yTm 3+ , where M is any one of Ba, Sr, Ca or Mg, and x and y represent mole fractions, where 0.0005≤x≤0.003 and 0.01≤y≤0.2.

[0024] The MTiO3:Pr,Tm (M=Ba,Sr,Ca,Mg) non-sulfur red long-afterglow phosphor of the present invention has stronger water resistance and longer afterglow time. Moreover, the preparation of this material does not require the use of sulfiding agents or elemental sulfur, which makes it safer and reduces the risk management cost.

[0025] This application provides a method for preparing the aforementioned non-sulfur red long-afterglow phosphor, characterized by comprising the following steps: Mix the carbonate or oxide of M, and the oxides of Ti, Pr and Tm according to the stoichiometry of the chemical formula of the red long afterglow phosphor. A flux was added and sintering was carried out; the sintered product was crushed and then ball-milled to obtain the non-sulfur red long afterglow phosphor.

[0026] In one embodiment, the carbonate or oxide of M is BaCO3, SrCO3, CaCO3, or MgO; and the oxides of Ti, Pr, and Tm are TiO2, Pr6O, etc. 11 And Tm2O3.

[0027] This application develops a titanate-based red long-afterglow phosphor, MTiO3:Pr. 4+ ,Tm3+ (M = Ba, Sr, Ca, Mg) The matrix raw materials used in this system are oxides or carbonates of barium, strontium, calcium, and magnesium, and oxides of titanium. The activator raw material is praseodymium oxide. The raw materials are readily available and inexpensive. This system can be prepared using a traditional high-temperature solid-state method, resulting in low commercialization costs. The preparation process does not require the use of sulfiding agents or elemental sulfur, thus enhancing safety and reducing risk management costs.

[0028] In one embodiment, the flux is a mixture of AlF3 and H3BO3; the amount of flux added is 8-16% of the weight of the raw materials.

[0029] In one implementation method, the ratio of AlF3 to H3BO3 is 1:(5-15).

[0030] In one implementation method, the particle size of AlF3 is 180–220 mesh; the particle size of H3BO3 is 80–110 mesh. This invention develops a composite flux system using aluminum fluoride (200 mesh sieve) and boric acid (100 mesh sieve) as fluxes. This composite flux system with differentiated particle sizes increases the contact area between the flux and the raw materials, increases the frequency of collisions and the uniformity of dispersion between different raw materials during the high-temperature solid-state reaction, and avoids the agglomeration and clumping of raw materials, especially praseodymium oxide, during sintering, thus improving the integrity of the MTiO3 crystal structure. Simultaneously, aluminum fluoride and boric acid have oxidizing properties, which can promote the formation of Pr 3+ More complete oxidation, improving Pr 4+ Red light intensity.

[0031] As one implementation method, sintering is divided into staged sintering. The first sintering is carried out at 350-450℃ for 1-3 hours in an oxygen atmosphere; the second sintering is carried out at 1200-1400℃ for 3-5 hours in an oxygen atmosphere.

[0032] This application introduces an oxidizing atmosphere during the preparation of long-afterglow phosphors in the Pr system, making Pr 3+ Sufficient oxidation was achieved, successfully realizing red long afterglow MTiO3:Pr 4+ ,Tm 3+ The brightness of (M=Ba, Sr, Ca, Mg) phosphors is significantly enhanced. Previous reports on the luminescence of praseodymium ions with long red afterglow were primarily in the +3 valence state. This application found that the stronger the oxidizing power of the sintering atmosphere, the higher the afterglow brightness of the red long-afterglow phosphor, indicating that in the MTiO3 matrix system, Pr... 4+ It has higher red light luminous efficiency, and its principle may be similar to Pr 4+ The outer electrons are 4f 1 This outer electron distribution is related to Ce, which has high luminescence efficiency. 3+Similarly, electronic transitions are more frequent and light conversion efficiency is higher in the MTiO3 (M=Ba, Sr, Ca, Mg) matrix system. The use of an oxygen atmosphere plays an important role in the preparation of high-efficiency MTiO3:Pr red long-afterglow phosphors.

[0033] As one implementation method, ball milling uses water as a medium; During the ball milling process, the mass ratio of phosphor, water and milling balls is 1:(1.5~1.9):(2~2.5); the ball milling time is 2~5h.

[0034] As one implementation method, the ball-milled slurry is sieved, separated from solids and liquids, and dried to obtain the non-sulfur red long afterglow phosphor.

[0035] In one implementation method, the sieve is a 200-mesh sieve; the solid-liquid separation is carried out by vacuum filtration; the drying temperature is 100-130℃, and the drying time is 8-24 hours.

[0036] As one implementation method, after the raw materials are mixed, they are dispersed by sieving and then mixed evenly again.

[0037] Pr doped ions 4+ Tm 3+ During the formation of MTiO3 materials, Pr 4+ Tm 3+ The oxides are hygroscopic and have high powder viscosity. When mixed with other raw materials in a mixer, they are prone to agglomeration and clumping. After sintering, Pr 4+ Tm 3+ The inability to disperse uniformly in the MTiO3 matrix results in low afterglow brightness of the red long-afterglow phosphor. To address the issue of low afterglow brightness caused by unevenness in the high-temperature solid-state calcined titanate blocks, this application provides a simplified raw material pretreatment process. After initial mixing of the raw materials, they are sieved and dispersed to further improve the uniformity of the mixture. The pre-dispersion of the raw materials is combined with a composite fluxing system, avoiding localized agglomeration and incomplete reaction. The calcined non-sulfur red long-afterglow blocks have a uniform color. The pretreatment process and the composite fluxing system improve the afterglow brightness of the obtained powder by approximately 74% and 39%, respectively.

[0038] This application also provides an application of a non-sulfur red long-afterglow phosphor in light-emitting or lighting devices.

[0039] The following is a further explanation using specific embodiments.

[0040] Example 1 (1) The chemical formula of the red long-afterglow phosphor is Ba. 0.9 Ti 0.998 O3:0.002Pr4+ 0.1Tm 3+ Weigh out BaCO3, TiO2, and Pr6O according to their chemical formula molar ratio. 11 The main raw material is Tm2O3, with the addition of fluxes AlF3 (180 mesh sieve) and H3BO3 (80 mesh sieve), which are mixed evenly in a mixer. The total content of flux accounts for 11% of the total weight of the main raw materials, and the ratio of AlF3 to H3BO3 is 1:10.

[0041] (2) Take out the mixed material from the mixer, sieve it through a 100-mesh screen to disperse it, then put it back into the mixer and mix for 30 minutes. Take it out and fill it into an alumina crucible. Make holes in the powder to ensure that the powder is in full contact with the atmosphere inside the furnace. Cover it with a slotted cover and put it into a 400℃ sintering furnace for a first sintering for 2 hours in an oxygen atmosphere. Cool it to room temperature and continue to put it into a 1300℃ sintering furnace for a second sintering for 4 hours in an oxygen atmosphere.

[0042] (3) After cooling to room temperature, the sintered block is taken out from the crucible and initially crushed by a jaw crusher roller device. It is ball-milled for 4 hours according to the ratio of powder:water:φ5 grinding ball=1:1.7:2.2. The slurry is passed through a 200-mesh sieve, filtered, and dried at 120℃ for 12 hours to obtain non-sulfur red long afterglow phosphor.

[0043] Example 2 (1) The chemical formula of the red long-afterglow phosphor is Sr 0.99 Ti 0.9995 O3:0.0005Pr 4+ 0.01Tm 3+ Weigh out SrCO3, TiO2, and Pr6O according to their chemical formula molar ratio. 11 The main raw material is Tm2O3, with the addition of fluxes AlF3 (220 mesh sieve) and H3BO3 (100 mesh sieve), which are mixed evenly in a mixer. The total content of flux accounts for 8% of the total weight of the main raw materials, and the ratio of AlF3 to H3BO3 is 1:10.

[0044] (2) Take out the mixed material from the mixer, sieve it through a 100-mesh screen to disperse it, then put it back into the mixer and mix for 30 minutes. Take it out and fill it into an alumina crucible. Make holes in the powder to ensure that the powder is in full contact with the atmosphere inside the furnace. Cover it with a slotted cover and put it into a 400℃ sintering furnace for a first sintering for 2 hours in an oxygen atmosphere. Cool it to room temperature and continue to put it into a 1300℃ sintering furnace for a second sintering for 4 hours in an oxygen atmosphere.

[0045] (3) After cooling to room temperature, the sintered block is taken out from the crucible and initially crushed by a jaw crusher roller device. It is ball-milled for 5 hours at a ratio of powder:water:φ5 grinding ball=1:1.7:2.2. The slurry is passed through a 200-mesh sieve, filtered, and dried at 120℃ for 12 hours to obtain non-sulfur red long afterglow phosphor.

[0046] Example 3 (1) The chemical formula of the red long-afterglow phosphor is Ca 0.92 Ti 0.999 O3:0.001Pr 4+ 0.08Tm 3+ Weigh out CaCO3, TiO2, and Pr6O according to their chemical formula molar ratio. 11 The main raw material is Tm2O3, with the addition of AlF3 (200-mesh sieve) and H3BO3 (100-mesh sieve) as fluxes. The mixture is thoroughly mixed in a mixer. The total content of flux accounts for 16% of the total weight of the main raw materials, and the ratio of AlF3 to H3BO3 is 1:10.

[0047] (2) Take out the mixed material from the mixer, sieve it through a 100-mesh screen to disperse it, then put it back into the mixer and mix for 30 minutes. Take it out and fill it into an alumina crucible. Make holes in the powder to ensure that the powder is in full contact with the atmosphere inside the furnace. Cover it with a slotted cover and put it into a 400℃ sintering furnace for a first sintering for 2 hours in an oxygen atmosphere. Cool it to room temperature and continue to put it into a 1300℃ sintering furnace for a second sintering for 4 hours in an oxygen atmosphere.

[0048] (3) After cooling to room temperature, the sintered block is taken out from the crucible and initially crushed by a jaw crusher roller device. It is ball-milled for 2 hours at a ratio of powder:water:φ5 grinding ball=1:1.7:2.2. The slurry is passed through a 200-mesh sieve, filtered, and dried at 120℃ for 12 hours to obtain non-sulfur red long afterglow phosphor.

[0049] Example 4 (1) The chemical formula of the red long afterglow phosphor is Mg 0.8 Ti 0.997 O3:0.003Pr 4+ 0.2Tm 3+ Weigh out MgO, TiO2, and Pr6O according to their chemical formula molar ratio. 11 The main raw material is Tm2O3, with the addition of fluxes AlF3 (200-mesh sieve) and H3BO3 (110-mesh sieve), which are mixed evenly in a mixer. The total content of flux accounts for 16% of the total weight of the main raw materials, and the ratio of AlF3 to H3BO3 is 1:10.

[0050] (2) Take out the mixed material from the mixer, sieve it through a 100-mesh screen to disperse it, then put it back into the mixer and mix for 30 minutes. Take it out and fill it into an alumina crucible. Make holes in the powder to ensure that the powder is in full contact with the atmosphere inside the furnace. Cover it with a slotted cover and put it into a 400℃ sintering furnace for a first sintering for 2 hours in an oxygen atmosphere. Cool it to room temperature and continue to put it into a 1300℃ sintering furnace for a second sintering for 4 hours in an oxygen atmosphere.

[0051] (3) After cooling to room temperature, the sintered block is taken out from the crucible and initially crushed by a jaw crusher roller device. It is ball-milled for 3 hours at a ratio of powder:water:φ5 grinding ball=1:1.7:2.2. The slurry is passed through a 200-mesh sieve, filtered, and dried at 120℃ for 12 hours to obtain non-sulfur red long afterglow phosphor.

[0052] Comparative Example 1 A non-sulfur red long-afterglow phosphor Ca 0.92 Ti 0.999 O3:0.001Pr 4+ 0.08Tm 3+ The preparation process is basically the same as in Example 3, except that the sintering atmosphere in step (2) is modified from "oxygen atmosphere" to "hydrogen reducing atmosphere, with a hydrogen to nitrogen ratio of 5:95".

[0053] Comparative Example 2 A non-sulfur red long-afterglow phosphor Ca 0.92 Ti 0.999 O3:0.001Pr 4+ 0.08Tm 3+ The preparation process is basically the same as in Example 3, except that the sintering atmosphere in step (2) is modified from "oxygen atmosphere" to "nitrogen atmosphere".

[0054] Comparative Example 3 A non-sulfur red long-afterglow phosphor Ca 0.92 Ti 0.999 O3:0.001Pr 4+ 0.08Tm 3+ Its preparation process is basically the same as that of Example 3, except that the sintering atmosphere in step (2) is modified from "oxygen atmosphere" to "air atmosphere".

[0055] Comparative Example 4 A non-sulfur red long-afterglow phosphor Ca 0.92 Ti 0.999 O3:0.001Pr 4+ 0.08Tm 3+ The preparation process is basically the same as that in Example 3, except that the sieving of the mixed materials in step (2) was modified and the "100-mesh sieve dispersion" operation was deleted.

[0056] Comparative Example 5 A non-sulfur red long-afterglow phosphor Ca 0.92 Ti 0.999 O3:0.001Pr 4+ 0.08Tm 3+The preparation process is basically the same as in Example 3, except that the flux in step (1) is modified. "H3BO3 with a 100-mesh sieve" is deleted, and only AlF3 with a 200-mesh sieve is used as the flux.

[0057] Comparative Example 6 A non-sulfur red long-afterglow phosphor Ca 0.92 Ti 0.999 O3:0.001Pr 4+ 0.08Tm 3+ The preparation process is basically the same as in Example 3, except that the flux in step (1) was modified. "AlF3 with a 200-mesh sieve" was deleted, and only H3BO3 with a 100-mesh sieve was used as the flux.

[0058] Comparative Example 7 A non-sulfur red long-afterglow phosphor Ca 0.92 Ti 0.999 O3:0.001Pr 4+ 0.08Tm 3+ The preparation process is basically the same as in Example 3, except that the flux in step (1) is modified. Instead of "adding AlF3 with a 200-mesh flux and H3BO3 with a 100-mesh flux", it is changed to "adding AlF3 with a 200-mesh flux and H3BO3 with a 200-mesh flux".

[0059] Comparative Example 8 A commercially available red long-afterglow Y₂O₂S:Eu,Ti,Mg was prepared according to the comparative example in authorized patent CN117801820B, "A Red Long-Afterglow Material and Its Preparation Method," with the specific steps as follows: (1) Weigh the raw materials according to the following proportions: Y2O3:1mol, S:1.54mol, TiO2:0.06mol, Eu2O3:0.024mol, MgO:0.04mol, and add 0.07mol Na2CO3 as a flux. Mix the weighed raw materials evenly and fill them into a corundum crucible. Make 6 holes, put carbon blocks in, and send it into a high-temperature furnace for sintering. The sintering temperature is 1300℃~1400℃, the holding time is 2~4h, N2 is purged as a protective atmosphere, and after cooling in the furnace, take it out and obtain powder by crushing and sieving.

[0060] (2) Place the Y2O2S powder obtained in step (1) in a hydrochloric acid solution with pH ≤ 2 and stir for 0.5 to 1 hour to remove excess S impurities. Wash with hot water several times to adjust the pH to neutral.

[0061] (3) Dehydrate, dry and finally sieve the powder after step (2) to obtain Y2O2S:0.024Eu:0.06Ti:0.04MgO red long afterglow.

[0062] Characterization and performance testing The particle size, afterglow brightness, and afterglow threshold of Examples 1-4 were tested; the particle size, afterglow brightness, and afterglow threshold of Examples 1-4 are shown in Table 1; the afterglow performance was tested using a PR-305 long afterglow tester from Hangzhou Zhejiang University Tricolor Instrument Co., Ltd., with an excitation illuminance of 990 lx and an excitation time of 15 min.

[0063] Table 1. Particle size, afterglow brightness, and afterglow threshold of samples from Examples 1-4 and Comparative Example 8

[0064] As shown in Table 1, the particle size D50 of the samples in Examples 1-4 is approximately 13.5 μm. The initial afterglow brightness of the non-sulfur red long-afterglow phosphor in the examples can reach 279 mcd / m². 2 All of the above have afterglow thresholds of 5 hours or more. Compared with Comparative Example 8 in the table, i.e., the commonly used commercially available Y2O2S:Eu,Ti,Mg red long afterglow phosphor, the non-sulfur red long afterglow phosphor of the present invention not only has the advantage of a longer afterglow time, but also has a brightness close to that of the sulfur-containing red long afterglow phosphor of Y2O2S:Eu,Ti,Mg.

[0065] SEM and emission spectra of the sample in Example 3 are as follows: Figure 1 , Figure 2 As shown, the appearance is 10~20μm granular blocky, and it emits red light at 613nm when excited at 380nm.

[0066] Table 2 shows a comparison of the afterglow performance of Example 3 with Comparative Examples 1-3.

[0067] Table 2. Particle size, afterglow brightness, and afterglow threshold of Example 3 and Comparative Examples 1-3

[0068] The main difference between Comparative Examples 1-3 and the four samples in Example 3 lies in the sintering atmosphere. Example 3 used an oxygen atmosphere, while Comparative Examples 1, 2, and 3 used a hydrogen / nitrogen mixed reducing atmosphere, a nitrogen atmosphere, and an air atmosphere, respectively. As shown in Table 2, the particle sizes of the four samples are similar, but their afterglow performance differs significantly, ranked from best to worst as follows: Example 3 > Comparative Example 3 > Comparative Example 2 > Comparative Example 1. The initial afterglow brightness of the Example 3 sample sintered in an oxygen atmosphere is approximately 9.7 times that of the Comparative Example 1 sample sintered in a reducing atmosphere, indicating that the oxidizing atmosphere has a crucial influence on the afterglow performance of the non-sulfur red long afterglow of CaTiO3:Pr,Tm. This invention uses an oxidizing atmosphere to... 3+ Pr was prepared by oxidation. 4+Doped MTiO3:Pr,Tm (M=Ba,Sr,Ca,Mg) non-sulfur red long-afterglow phosphor, possessing similar properties to Ce 3+ Pr with the same outer electron structure 4+ In the MTiO3 (M=Ba, Sr, Ca, Mg) matrix system, electronic transitions are more frequent, resulting in higher light conversion efficiency.

[0069] The comparison results of afterglow performance between Example 3 and Comparative Example 4 are shown in Table 3.

[0070] Table 3. Particle size, afterglow brightness, and afterglow threshold of Example 3 and Comparative Example 4

[0071] As can be seen from Table 3, the sample of Example 3, which was prepared after the raw materials were initially mixed and dispersed by sieving through a 100-mesh sieve, had an initial afterglow brightness that was about 74% higher than that of the sample of Comparative Example 4, and the afterglow threshold was also significantly increased.

[0072] The afterglow performance comparison results of Example 3 and Comparative Examples 5-7 are shown in Table 4.

[0073] Table 4. Particle size, afterglow brightness, and afterglow threshold of Example 3 and Comparative Examples 5-7

[0074] In Table 4, the afterglow brightness and afterglow threshold of the Example 3 sample and Comparative Example 7 sample, which used a composite of two fluxes, H3BO3 and AlF3, were superior to those of Comparative Examples 5 and 6, which used a single flux. Furthermore, compared to Comparative Example 7 sample, which used a composite of 200-mesh AlF3 and 200-mesh boric acid, the afterglow performance of the Example 3 sample, which used a composite of 200-mesh AlF3 and 100-mesh boric acid with differentiated particle sizes, was further improved. Compared to Comparative Examples 5 or 6, which used either H3BO3 or AlF3 alone, the initial afterglow brightness of the Example 3 sample was improved by approximately 39%.

[0075] In summary, this application has developed a titanate-based red long-afterglow phosphor, MTiO3:Pr. 4+ ,Tm 3+ (M=Ba, Sr, Ca, Mg) The raw materials are readily available, and the phosphor has a longer afterglow time. In response to the problem of low afterglow brightness caused by uneven solid-state firing of titanates, a raw material pretreatment process and a composite fluxing system are proposed to avoid local agglomeration and incomplete reaction of the raw materials. The fired non-sulfur red long afterglow blocks have a uniform color. An oxidizing atmosphere is introduced to fully oxidize the activator, which significantly improves the afterglow brightness of the phosphor.

[0076] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of those different embodiments or examples.

[0077] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0078] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various variations or substitutions within the technical scope disclosed in this application, and these should all be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A non-sulfur red long-afterglow phosphor, characterized in that, The chemical formula of the non-sulfur red long-afterglow phosphor is M. 1-y Ti 1-x O3: xPr 4+ yTm 3+ Where M is any one of Ba, Sr, Ca or Mg, and x and y represent mole fractions, where 0.0005≤x≤0.003 and 0.01≤y≤0.2; The preparation method of the non-sulfur red long-afterglow phosphor includes the following steps: The carbonate or oxide of M, and oxides of Ti, Pr, and Tm are mixed according to the stoichiometry of the chemical formula of the non-sulfur red long afterglow phosphor; the oxides of Ti, Pr, and Tm are TiO2 and Pr6O. 11 and Tm2O3; A flux was added and sintering was carried out; the sintered product was crushed and then ball-milled to obtain the non-sulfur red long afterglow phosphor. The flux is a mixture of AlF3 and H3BO3; Sintering is divided into stage sintering. The first sintering is carried out at 350-450℃ for 1-3 hours in an oxygen atmosphere; the second sintering is carried out at 1200-1400℃ for 3-5 hours in an oxygen atmosphere.

2. The method for preparing the non-sulfur red long-afterglow phosphor according to claim 1, characterized in that, Includes the following steps: The carbonate or oxide of M, and oxides of Ti, Pr, and Tm are mixed according to the stoichiometry of the chemical formula of the non-sulfur red long afterglow phosphor; the oxides of Ti, Pr, and Tm are TiO2 and Pr6O. 11 and Tm2O3; A flux was added and sintering was carried out; the sintered product was crushed and then ball-milled to obtain the non-sulfur red long afterglow phosphor. The flux is a mixture of AlF3 and H3BO3; Sintering is divided into stage sintering. The first sintering is carried out at 350-450℃ for 1-3 hours in an oxygen atmosphere; the second sintering is carried out at 1200-1400℃ for 3-5 hours in an oxygen atmosphere.

3. The method for preparing the non-sulfur red long-afterglow phosphor according to claim 2, characterized in that, The carbonate or oxide of M is BaCO3, SrCO3, CaCO3, or MgO.

4. The method for preparing the non-sulfur red long-afterglow phosphor according to claim 2, characterized in that, The amount of flux added is 8-16% of the weight of the raw materials.

5. The method for preparing the non-sulfur red long-afterglow phosphor according to claim 4, characterized in that, The ratio of AlF3 to H3BO3 is 1:(5-15).

6. The method for preparing the non-sulfur red long-afterglow phosphor according to claim 2, characterized in that, The particle size of AlF3 is 180~220 mesh; the particle size of H3BO3 is 80~110 mesh.

7. The method for preparing the non-sulfur red long-afterglow phosphor according to claim 2, characterized in that, Ball mills use water as the medium; During the ball milling process, the mass ratio of phosphor, water and milling balls is 1:(1.5-1.9):(2-2.5); the ball milling time is 2-5 hours.

8. The method for preparing the non-sulfur red long-afterglow phosphor according to claim 2, characterized in that, The slurry after ball milling is sieved, separated from solids and liquids, and dried to obtain the non-sulfur red long afterglow phosphor.

9. The method for preparing the non-sulfur red long-afterglow phosphor according to claim 2, characterized in that, After the raw materials are mixed, they are dispersed by sieving and then mixed again until uniform.

10. The application of the non-sulfur red long afterglow phosphor of claim 1 in light-emitting or lighting devices.

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