Na2SiF6:Mn with a rod-like structure 4+ Red phosphor, preparation method thereof, and application

Abstract

The present application discloses a rod-shaped Na2SiF6:Mn 4+ red phosphor and its preparation method and application. The diameter of the rod-shaped Na2SiF6:Mn 4+ red phosphor is 0.1 μm to 50 μm, and its aspect ratio is (1 to 10):1. This rod-shaped Na2SiF6:Mn 4+ red phosphor combines the characteristics of high brightness and short afterglow compared with the conventional amorphous Na2SiF6:Mn 4+ red phosphor, and the shortest afterglow lifetime can be reduced to 3.6 ms.

Description

Technical Field

[0001] This application relates to the technical field of phosphor materials, and in particular to a rod-shaped Na2SiF6:Mn 4+ red phosphor, its preparation method and application. Background Art

[0002] The fluoride red fluorescent material first reported by Paulusz of Osram in Germany in 1973 has a unique narrow-band emission near a wavelength of 630 nm. Therefore, it has extremely high color purity and a wide color gamut in backlight displays. In particular, the combination of narrow-band fluoride and narrow-band green phosphor β-SiAlON has been widely used in backlight display packaging devices. The known literature reports that the afterglow lifetime of fluoride narrow-band red phosphors is about 8 ms (such as K2SiF6:Mn developed by General Electric GE in the United States 4+ with a lifetime of 8.2 ms), which will cause a display ghosting phenomenon, and this has also become a defect in the use of narrow-band fluoride red phosphors in backlight devices. Summary of the Invention

[0003] This application provides a rod-shaped Na2SiF6:Mn 4+ red phosphor, its preparation method and application. The rod-shaped Na2SiF6:Mn 4+ red phosphor can improve the problem of long afterglow lifetime of current fluoride narrow-band red phosphors and has better luminous efficiency of the product.

[0004] In a first aspect, this application provides a rod-shaped Na2SiF6:Mn 4+ red phosphor. The diameter of the rod-shaped Na2SiF6:Mn 4+ red phosphor is from 0.1 μm to 50 μm, and its aspect ratio is (1-10):1. Preferably, the diameter of the rod-shaped Na2SiF6:Mn 4+ red phosphor is from 10 μm to 40 μm, and its aspect ratio is (1.5-3):1. More preferably, the diameter of the rod-shaped Na2SiF6:Mn 4+ red phosphor is from 15 μm to 30 μm, and its aspect ratio is (2-3):1. The rod-shaped Na2SiF6:Mn 4+ red phosphor described in this application, due to its regular rod-shaped particle morphology, and both the diameter and aspect ratio are also within the scope of this application. Thus, it is beneficial to reduce scattering and improve the luminous efficiency of the product. More importantly, compared with the conventional amorphous Na2SiF6:Mn 4+ red phosphor, it also has the characteristic of short afterglow, and its shortest afterglow lifetime can be reduced to 3.6 ms. Therefore, this application regulates Na2SiF6:Mn 4+The particle morphology of the red phosphor is rod-shaped, and its diameter length and aspect ratio are also within the scope of this application, which is conducive to achieving both short afterglow and high luminous efficiency.

[0005] In this application, the "length" in the "aspect ratio" refers to the length of the rod-shaped structure Na2SiF6:Mn 4+ of the red phosphor. Exemplarily, as Figure 8 shown, the "length" is the distance L between the two ends along the extension direction of the rod-shaped structure, the "longest diameter length" is the maximum diameter D1 measured in the plane of the longitudinal section perpendicular to the length direction, and the "shortest diameter length" is the minimum diameter D2 measured in the plane of the longitudinal section perpendicular to the length direction. Figure 8 The case of a prismatic rod is listed. In the actual synthesis process, due to the friction with the synthesizer and the polishing of the stirring action, the crystal edges and corners of the phosphor particles will become relatively smooth, showing a prismatic rod-like or cylindrical rod-like morphology, but the cross-sectional shape does not affect the performance indicators of the final powder. In some embodiments, the longitudinal section of the rod-shaped structure Na2SiF6:Mn 4+ of the red phosphor has a longest diameter length of D1 and a shortest diameter length of D2, where 0.3 ≤ D2 / D1 ≤ 1, preferably 0.5 ≤ D2 / D1 ≤ 0.8. The plane of the longitudinal section is perpendicular to the length direction of the rod-shaped structure Na2SiF6:Mn 4+ of the red phosphor. Thus, the luminous efficiency of the rod-shaped structure Na2SiF6:Mn 4+ of the red phosphor in this application is better, and the effect of shortening the afterglow lifetime is more obvious. Specifically, the rod-shaped structure Na2SiF6:Mn 4+ of the red phosphor in this application has a peak wavelength of 627.1 nm, a peak intensity of 1820 - 1870 under 455 nm excitation, shows narrow-band emission, the full width at half maximum of the emission peak is below 8 nm, and the afterglow lifetime is 3.6 ms to 5.5 ms.

[0006] Second, this application provides a preparation method of the red phosphor with the rod-shaped structure Na2SiF6:Mn 4+ as described in any one of the first aspects above, including the following steps:

[0007] (1) Weigh Na2SiF6 solid powder and Na2MnF6 solid powder according to the stoichiometric ratio, dissolve the Na2SiF6 solid powder and the Na2MnF6 solid powder in a hydrofluoric acid solution, heat to 55°C to 65°C, and stir to obtain a first solution.

[0008] (2) Weigh NaF solid powder, dissolve the NaF solid powder in a hydrofluoric acid solution, heat to 55°C to 65°C, and stir to obtain a second solution.

[0009] Among them, in (1) and (2), the mass concentration of the hydrofluoric acid solution is 45 wt% to 55 wt%. Preferably, the mass concentration of the hydrofluoric acid solution is 50 wt%.

[0010] (3) Mix the first solution and the second solution respectively at a jet flow rate of 10 g / min to 100 g / min, and carry out a tubular flow reaction under a low-temperature environment. After crystallization, stir and let stand.

[0011] (4) Pour off the supernatant, wash the precipitate, and dry it to obtain the Na2SiF6:Mn 4 + red phosphor of the present application with a rod-like structure.

[0012] The present application adopts a wet synthesis method with a high supersaturation degree (reacting under a low-temperature environment, at this time the concentration c* that the system can accommodate will be very limited, creating a high supersaturation environment), and obtains a Na2SiF6:Mn 4+ narrow-band fluoride red phosphor with a rod-like morphology. Due to the use of a tubular flow reaction with a high supersaturation degree during the preparation process, a large number of non-radiative transitions are introduced when the phosphor particles are excited. Therefore, the Na2SiF6:Mn 4+ red phosphor of the present application with a rod-like structure has a lower afterglow lifetime. Moreover, because its regular (appropriate diameter length and aspect ratio) rod-like structure reduces the brightness loss caused by scattering in the encapsulation device compared with the amorphous structure of the prior art, it shows a higher luminous efficiency in the encapsulation device. Supersaturation = (c - c*) / c*, where c* is the concentration at which dissolution equilibrium is reached in the system, and c is the actual concentration of the substance in the system. Its physical meaning represents the degree to which the solution system exceeds the saturated concentration.

[0013] In some embodiments, the sum of the masses of the Na2SiF6 solid powder and the Na2MnF6 solid powder is W1, the mass of the hydrofluoric acid solution is W2, and the mass of the NaF solid powder is W3, satisfying at least one of the following conditions: (1) 0.023 ≤ W1 / W2 ≤ 0.025; (2) 0.072 ≤ W3 / W2 ≤ 0.08.

[0014] In some embodiments, in step (3), at least one of the following conditions is satisfied: (1) The jet velocity of the first solution is V1, and the jet velocity of the second solution is V2, where 0.1 ≤ V1 / V2 ≤ 2. (2) The ambient temperature of the tubular flow reaction is below 0°C, and the length of its tubular channel is not less than 10 m. (3) The stirring speed is 30 rpm to 100 rpm, and the stirring time is 1.5 h to 2 h. By regulating the relative velocity of the first solution and the second solution within the above range, and at the same time, synergistically regulating the ambient temperature of the tubular reaction to be below 0°C, a reaction environment with high supersaturation is created, which is conducive to growing rod-shaped Na2SiF6:Mn 4+ red phosphor, so as to generate more non-radiative transitions in the crystal structure, thereby shortening the afterglow lifetime and improving the light efficiency. At the same time, further regulating the stirring speed after crystallization within the above range is conducive to obtaining a rod-shaped Na2SiF6:Mn with a suitable aspect ratio (D2 / D1) 4+ red phosphor, and the effect of improving the light efficiency and shortening the afterglow lifetime is better.

[0015] In a third aspect, the present application provides any one of the above-mentioned first aspects of the rod-shaped Na2SiF6:Mn 4+ red phosphor or the rod-shaped Na2SiF6:Mn 4+ red phosphor prepared by the preparation method of any one of the above-mentioned second aspects in the application of an LED backlight.

[0016] In a fourth aspect, the present application provides an LED backlight, the LED backlight includes an excitation chip and a phosphor coated on the excitation chip, and the phosphor includes any one of the above-mentioned first aspects of the rod-shaped Na2SiF6:Mn 4+ red phosphor; or, the phosphor is a rod-shaped Na2SiF6:Mn 4+ red phosphor prepared by the preparation method of any one of the above-mentioned second aspects.

[0017] In some embodiments, the median particle size D50 of the phosphor is greater than 0.1 μm and less than 50 μm. Preferably, the median particle size D50 of the phosphor is greater than 5 μm and less than 30 μm. In this way, the afterglow lifetime of the product is shorter and the light efficiency is better.

[0018] In some embodiments, based on the total mass of the phosphor, the mass percentage content of the rod-shaped Na2SiF6:Mn 4+ red phosphor is higher than 30 wt%. Preferably, the rod-shaped Na2SiF6:Mn 4+The mass percentage content of the red phosphor is higher than 50 wt%. In this way, the product has a shorter afterglow lifetime and higher luminous efficiency.

[0019] Compared with the prior art, the present application has the following beneficial effects:

[0020] The present application adopts a wet synthesis method with high supersaturation to obtain a rod-shaped Na2SiF6:Mn 4 + narrow-band fluoride red phosphor. By regulating the particle parameters of the rod-shaped structure Na2SiF6:Mn 4+ red phosphor within the scope of the present application, its luminous efficiency is better and the afterglow lifetime is shorter compared with the conventional amorphous Na2SiF6:Mn 4+ red phosphor, and the shortest afterglow lifetime can be reduced to 3.6 ms. Description of the Drawings

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required to be used in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present application. For those skilled in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 SEM image of the Na2SiF6:Mn 4+ red phosphor prepared in Comparative Example 2 of the present application;

[0023] Figure 2 SEM image of the Na2SiF6:Mn 4+ red phosphor prepared in Example 1 of the present application;

[0024] Figure 3 SEM image of the Na2SiF6:Mn 4+ red phosphor prepared in Example 3 of the present application;

[0025] Figure 4 SEM image of the Na2SiF6:Mn 4+ red phosphor obtained in Example 5 of the present application;

[0026] Figure 5 XRD pattern of the rod-shaped Na2SiF6:Mn 4+ red phosphor prepared in Example 5 of the present application;

[0027] Figure 6 XRD pattern of the rod-shaped Na2SiF6:Mn4+ Emission spectrum of the red phosphor under 455 nm excitation;

[0028] Figure 7 The rod-shaped structure Na2SiF6:Mn prepared in Example 5 of this application 4+ Afterglow lifetime test chart of the red phosphor;

[0029] Figure 8 Schematic diagram of the structure of the multi-prismatic rod-shaped phosphor particles. Detailed implementation manners

[0030] In order to make the objectives, technical solutions and advantages of this application clearer, the following further elaborates on this application in combination with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit this application.

[0031] With the in-depth research, Na2SiF6:Mn 4+ Because it has a shorter peak wavelength than KSF (K2SiF6:Mn 4+ ) and has higher brightness (the wavelength is closer to the sensitive area of the human eye), and its shorter afterglow than KSF has once again become a research hotspot for fluoride phosphors. The known literature reports that the afterglow lifetime of fluoride narrow-band red phosphors is about 8 ms, resulting in a ghosting phenomenon on display devices, which also becomes a defect in the use of fluoride red phosphors in backlight devices. The purpose of this application is to obtain a high-brightness, short-afterglow fluoride red phosphor to solve the above technical problems.

[0032] The rod-shaped structure Na2SiF6:Mn 4+ Red phosphor:

[0033] The rod-shaped structure Na2SiF6:Mn 4+ The diameter length of the rod-shaped structure Na2SiF6:Mn red phosphor is from 0.1 μm to 50 μm, and the length-diameter ratio is (1-10):1. In some embodiments, its diameter length is from 10 μm to 40 μm, and its length-diameter ratio is (1.5-3):1. In some embodiments, its diameter length is from 15 μm to 30 μm, and its length-diameter ratio is (2-3):1. The rod-shaped structure Na2SiF6:Mn red phosphor described in this application 4+ Due to its regular particle morphology (both the diameter length and the length-diameter ratio are within the above ranges), the red phosphor can reduce scattering and improve the light efficiency of the product. Moreover, compared with the conventional amorphous morphology Na2SiF6:Mn 4+ Red phosphor also has the characteristic of short afterglow, and its shortest afterglow lifetime can be reduced to 3.6 ms. Therefore, the core technical concept of this application is to regulate Na2SiF6:Mn 4+The particle morphology of the red phosphor is rod-shaped, and its diameter length and aspect ratio are within the above ranges, which is beneficial to achieving both short afterglow and high luminous efficiency. In some examples, the rod-shaped structure Na2SiF6:Mn 4+ The diameter length of the red phosphor can be 0.1μm, 1μm, 5μm, 8μm, 10μm, 13μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 48μm, 50μm or a value within the range composed of any two of these values. In some examples, the value of the aspect ratio can be 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 5:1, 6:1, 8:1, 9:1, 10:1 or a value within the range composed of any two of these values.

[0034] In some embodiments, the rod-shaped structure Na2SiF6:Mn 4+ For the red phosphor, the longest diameter length of the longitudinal section is D1, the shortest diameter length is D2, and 0.3 ≤ D2 / D1 ≤ 1. The plane where the longitudinal section is located is perpendicular to the length direction of the rod-shaped structure Na2SiF6:Mn 4+ red phosphor. In some embodiments, 0.5 ≤ D2 / D1 ≤ 0.8. By regulating the ratio of the shortest diameter length to the longest diameter length of the rod-shaped structure Na2SiF6:Mn 4+ red phosphor within the above range, the luminous efficiency of the product can be further improved and the afterglow lifetime can be shortened. Exemplarily, the value of D2 / D1 can be 0.3, 0.35, 0.39, 0.41, 0.48, 0.5, 0.62, 0.63, 0.7, 0.74, 0.8, 0.88, 0.90, 0.98, 1 or a value within the range composed of any two of these values.

[0035] In some embodiments, the rod-shaped structure Na2SiF6:Mn 4+ red phosphor has a peak wavelength of 627.1nm and a peak intensity of 1820 - 1870 under 455nm excitation, and shows narrow-band emission, and the full width at half maximum of the emission peak is below 8nm. Specifically, the full width at half maximum of the emission peak is 7.7nm.

[0036] In some embodiments, the rod-shaped structure Na2SiF6:Mn 4+ red phosphor has an afterglow lifetime of 3.6ms to 5.5ms.

[0037] Preparation method of the rod-shaped structure Na2SiF6:Mn 4+ red phosphor:

[0038] Step 1: Weigh Na2SiF6 solid powder and Na2MnF6 solid powder according to the stoichiometric ratio. Dissolve the Na2SiF6 solid powder and the Na2MnF6 solid powder in a hydrofluoric acid solution, heat to 55°C to 65°C, and stir to obtain a first solution.

[0039] Step 2: Weigh NaF solid powder. Dissolve the NaF solid powder in a hydrofluoric acid solution, heat to 55°C to 65°C, and stir to obtain a second solution.

[0040] Step 3: Mix the first solution and the second solution at a jet velocity of 10 g / min to 100 g / min respectively, and carry out a tubular flow reaction under a low-temperature environment. After crystallization, stir and let stand.

[0041] Step 4: Pour off the supernatant, wash the precipitate, and dry it to obtain the rod-shaped structure Na2SiF6:Mn 4+ red phosphor.

[0042] Among them, the preparation order of Step 1 and Step 2 can be adjusted as long as the weighing is carried out according to the stoichiometric ratio, and this application does not make any restrictions.

[0043] In some embodiments, the mass concentration of the hydrofluoric acid solution is 45 wt% to 55 wt%. Preferably, the mass concentration of the hydrofluoric acid solution is 50 wt%.

[0044] In some embodiments, the sum of the masses of the Na2SiF6 solid powder and the Na2MnF6 solid powder is W1, the mass of the hydrofluoric acid solution is W2, and the mass of the NaF solid powder is W3, satisfying at least one of the following conditions: (1) 0.023 ≤ W1 / W2 ≤ 0.025; (2) 0.072 ≤ W3 / W2 ≤ 0.08.

[0045] In some embodiments, in step (3), at least one of the following conditions is satisfied: (1) The jet velocity of the first solution is V1, the jet velocity of the second solution is V2, and 0.1 ≤ V1 / V2 ≤ 2. (2) The ambient temperature of the tubular flow reaction is below 0°C, and the length of its tubular channel is not less than 10 m. (3) The stirring speed is 30 rpm to 100 rpm, and the stirring time is 1.5 h to 2 h. In this way, the effect of improving the product luminous efficiency and shortening the afterglow life is better.

[0046] To further illustrate the present invention, through some implementation cases, the remarkable features of the invention are further elaborated, but the scope of the invention is not limited. Those skilled in the art will understand that the preparation methods described in this application are only examples, and any other suitable preparation methods are within the scope of this application. Various tests and evaluations are carried out according to the following methods. In addition, unless otherwise specified, "parts" and "%" are based on mass.

[0047] Test method: Use a fluorescence lifetime analyzer and a spectral radiance analyzer to perform afterglow lifetime and spectral tests on the synthesized powder. For specific operations, reference can be made to the conventional steps of the prior art.

[0048] Comparative Example 1

[0049] Commercially available K2SiF6:Mn 4+ (Potassium fluorosilicate activated by tetravalent manganese)

[0050] Comparative Example 2

[0051] Weigh 15 g of solid powder of Na2MnF6 and dissolve it in 500 g of commercially available 10%-15% fluorosilicic acid (H2SiF6) to prepare the first solution. Separately, dissolve 36 g of solid powder of NaF in 500 g of 50% hydrofluoric acid (electronic grade) to obtain the second solution. Inject the first solution into the second solution at a rate of 10 g / min with mechanical stirring, and the stirring temperature is 40 °C. After the reaction solution is stirred for 2 h, pour out the supernatant, add HF (5%) and stir for washing for 2 h, wash twice with ethanol, and dry to obtain Na2SiF6:Mn 4+ Red phosphor. The SEM diagram of the Na2SiF6:Mn 4+ Red phosphor obtained in Comparative Example 2 is as shown in Figure 1 In the figure, the Na2SiF6:Mn 4+ Red phosphor obtained in Comparative Example 2 are all amorphous particles.

[0052] Comparative Example 3

[0053] Step 1: Take 10 g of sodium fluorosilicate (Na2SiF6) and 1.5 g of sodium fluoromanganate (Na2MnF6) solid powder, and dissolve them in 500 g of commercially available 50% hydrofluoric acid (electronic grade), and heat to 60 °C and stir evenly to obtain the first solution.

[0054] Step 2: Take 36 g of solid powder of NaF, and similarly dissolve it in 500 g of commercially available 50% hydrofluoric acid (electronic grade), and heat to 60 °C and stir evenly to obtain the second solution.

[0055] Step 3: Inject the first solution and the second solution into a 1000 ml Teflon cavity at jet velocities of 50 g / min (V1) and 10 g / min (V2) (V1 / V2 = 5) respectively for mixing, and then quickly flow into a tubular flow reaction channel at a temperature of 25°C. The length of the tubular channel is 10 m. After crystallization in the tubular flow channel, stir at 60 rpm for 2 h and then let it stand.

[0056] Step 4: Pour out the supernatant, add HF (5%) and stir for washing for 2 h, wash twice with ethanol, and then dry.

[0057] Example 1

[0058] Step 1: Take 10 g of solid powder of sodium hexafluorosilicate (Na2SiF6) and 1.5 g of solid powder of sodium hexafluoromanganate (Na2MnF6), dissolve them in 500 g of commercially available 50% hydrofluoric acid (electronic grade), and heat to 60°C and stir evenly to obtain the first solution.

[0059] Step 2: Take 36 g of solid powder of sodium fluoride (NaF), and similarly dissolve it in 500 g of commercially available 50% hydrofluoric acid (electronic grade), heat to 60°C and stir evenly to obtain the second solution.

[0060] Step 3: Inject the first solution and the second solution into a 1000 ml Teflon cavity at jet velocities of 30 g / min (V1) and 10 g / min (V2) (V1 / V2 = 3) respectively for mixing, and then quickly flow into a tubular flow reaction channel at a temperature of 5°C. The length of the tubular channel is 10 m. After crystallization in the tubular flow channel, stir at 60 rpm for 2 h and then let it stand.

[0061] Step 4: Pour out the supernatant, add HF (5%) and stir for washing for 2 h, wash twice with ethanol, and then dry to obtain Na2SiF6:Mn 4 + Red phosphor. D2 / D1 is 0.7, and other test parameters are shown in Table 1.

[0062] Figure 2 SEM image of the Na2SiF6:Mn red phosphor prepared in Example 1. It can be seen that the Na2SiF6:Mn red phosphor obtained in Example 1 4+ has a rod-like morphology. 4+ Red phosphor is in a rod-like morphology.

[0063] Figure 5 XRD pattern of the Na2SiF6:Mn red phosphor prepared in Example 1. Its X-ray diffraction peaks are consistent with the standard card of Na2SiF6 (PDF#33-1280), and it has high crystallinity and no other impurities. 4+ The X-ray diffraction peaks are consistent with the standard card of Na2SiF6 (PDF#33-1280), and it has high crystallinity and no other impurities.

[0064] Figure 6Na2SiF6:Mn prepared in Example 1 4+ Emission spectrum of the red phosphor under 455 nm excitation, with a narrow-band red spectral emission having a peak wavelength near 627 nm and a full width at half maximum of 7.7 nm.

[0065] Example 2

[0066] Step 1: Take 10 g of sodium hexafluorosilicate (Na2SiF6) and 0.5 g of sodium manganese hexafluoride (Na2MnF6) solid powder, dissolve them in 500 g of commercially available 50% hydrofluoric acid (electronic grade), and heat to 60 °C and stir evenly to obtain the first solution.

[0067] Step 2: Take 36 g of sodium fluoride (NaF) solid powder, also dissolve it in 500 g of commercially available 50% hydrofluoric acid (electronic grade), and heat to 60 °C and stir evenly to obtain the second solution.

[0068] Step 3: Inject the first solution and the second solution into a 1000 ml Teflon cavity at jet velocities of 30 g / min (V1) and 12 g / min (V2) (V1 / V2 = 2.5) respectively for mixing, and quickly flow into a tubular flow reaction channel at 0 °C. The length of the tubular channel is 10 m. After crystallization in the tubular flow channel, stir at 60 rpm for 2 h and then let it stand.

[0069] Step 4: Pour off the supernatant, add HF (5%) and stir and wash for 2 h, wash twice with ethanol, and dry to obtain Na2SiF6:Mn 4 + Red phosphor. D2 / D1 is 0.7, and other test parameters are shown in Table 1.

[0070] Example 3

[0071] Step 1: Take 10 g of sodium hexafluorosilicate (Na2SiF6) and 1.5 g of sodium manganese hexafluoride (Na2MnF6) solid powder, dissolve them in 500 g of commercially available 50% hydrofluoric acid (electronic grade), and heat to 60 °C and stir evenly to obtain the first solution.

[0072] Step 2: Take 36 g of sodium fluoride (NaF) solid powder, also dissolve it in 500 g of commercially available 50% hydrofluoric acid (electronic grade), and heat to 60 °C and stir evenly to obtain the second solution.

[0073] Step 3: Inject the first solution and the second solution into a 1000 ml Teflon cavity at jet velocities of 40 g / min (V1) and 20 g / min (V2) (V1 / V2 = 2) respectively for mixing, and quickly flow into a tubular flow reaction channel at 0 °C. The length of the tubular channel is 10 m. After sufficient crystallization in the tubular flow channel, stir at 60 rpm for 2 h and then let it stand.

[0074] Step 4: Pour off the supernatant, add HF (5%) and stir for washing for 2 h, wash twice with ethanol, and dry to obtain Na2SiF6:Mn 4 + Red phosphor. D2 / D1 is 0.7, and other test parameters are shown in Table 1.

[0075] Figure 3 It is the Na2SiF6:Mn red phosphor prepared in Example 3 4+ SEM image of the Na2SiF6:Mn red phosphor prepared in Example 3, the Na2SiF6:Mn red phosphor prepared in Example 3 4+ Red phosphor has a rod-like morphology.

[0076] Example 4

[0077] Step 1: Take 10 g of Na2SiF6 sodium fluorosilicate and 1.5 g of Na2MnF6 sodium fluoromanganate solid powders, dissolve them in 500 g of commercially available 50% hydrofluoric acid (electronic grade), and heat to 60 °C and stir evenly to obtain the first solution.

[0078] Step 2: Take 36 g of NaF solid powder, also dissolve it in 500 g of commercially available 50% hydrofluoric acid (electronic grade), and heat to 60 °C and stir evenly to obtain the second solution.

[0079] Step 3: Spray the first solution and the second solution into a 1000 ml Teflon cavity at jet velocities of 40 g / min (V1) and 20 g / min (V2) respectively (V1 / V2 = 2) for mixing, and quickly flow into a tubular flow reaction channel with a temperature of 0 °C. The length of the tubular channel is 10 m. After sufficient crystallization in the tubular flow channel, stir at 150 rpm for 1.5 h and then let it stand.

[0080] Step 4: Pour off the supernatant, add HF (5%) and stir for washing for 2 h, wash twice with ethanol, and dry to obtain Na2SiF6:Mn 4 + Red phosphor. D2 / D1 is 0.3, and other test parameters are shown in Table 1.

[0081] Example 5

[0082] Step 1: Take 10 g of Na2SiF6 sodium fluorosilicate and 1.5 g of Na2MnF6 sodium fluoromanganate solid powders, dissolve them in 500 g of commercially available 50% hydrofluoric acid (electronic grade), and heat to 60 °C and stir evenly to obtain the first solution.

[0083] Step 2: Take 36 g of NaF solid powder, also dissolve it in 500 g of commercially available 50% hydrofluoric acid (electronic grade), and heat to 60 °C and stir evenly to obtain the second solution.

[0084] Step 3: Inject the first solution and the second solution into a 1000 ml Teflon cavity at jet velocities of 40 g / min (V1) and 20 g / min (V2) respectively (V1 / V2 = 2) for mixing, and then quickly flow into a -45°C tubular flow reaction channel with a length of 10 m. After sufficient crystallization in the tubular flow channel, stir at 60 rpm for 2 h and then let it stand.

[0085] Step 4: Pour off the supernatant, add HF (5%) and stir for washing for 2 h, wash with ethanol twice, and dry to obtain Na2SiF6:Mn 4 + Red phosphor. D2 / D1 is 0.7, and other test parameters are shown in Table 1.

[0086] Figure 4 The Na2SiF6:Mn red phosphor prepared in Example 5 4+ SEM image of the Na2SiF6:Mn red phosphor prepared in Example 4 4+ The Na2SiF6:Mn red phosphor has a rod-like morphology.

[0087] Figure 7 The rod-like structure Na2SiF6:Mn red phosphor prepared in Example 5 4+ Lifetime test chart data of the Na2SiF6:Mn red phosphor. As can be seen from the figure, the rod-like structure Na2SiF6:Mn 4+ red phosphor has the characteristic of short afterglow lifetime.

[0088] Table 1

[0089]

[0090] This application uses a wet chemical synthesis process to synthesize Na2SiF6:Mn 4+ red phosphor with a suitable rod-like morphology. Compared with the conventional spherical and hexagonal morphologies, this rod-like structure fluoride phosphor has the characteristics of high luminous efficiency and short afterglow, and the shortest afterglow lifetime can be reduced to 3.6 ms.

[0091] The above are only the preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent replacements, and improvements made within the spirit and principle of this application shall be included within the protection scope of this application.

Claims

1. A rod-shaped Na2SiF6:Mn 4+ red phosphor, characterized in that The rod-shaped structure Na2SiF6:Mn 4+ The red phosphor has a diameter length of 0.1 μm to 50 μm and an aspect ratio of (1 to 10):1; The described Na2SiF6:Mn with a rod-like structure 4+ The preparation method of the red phosphor includes the following steps: (1) Weigh the solid powders of Na2SiF6 and Na2MnF6 according to the stoichiometric ratio, dissolve the solid powders of Na2SiF6 and Na2MnF6 in a hydrofluoric acid solution, heat to 55 °C to 65 °C, and stir to obtain a first solution; (2) Weigh the solid powder of NaF, dissolve the solid powder of NaF in a hydrofluoric acid solution, heat to 55 °C to 65 °C, and stir to obtain a second solution; (3) Mix the first solution and the second solution respectively at a jet velocity of 10 g / min to 100 g / min, conduct a tube-flow reaction under a low-temperature environment, and after crystallization, stir and let stand; the ambient temperature of the tube-flow reaction is below 0 °C; (4) Decant the supernatant, wash the precipitate, and obtain the Na2SiF6:Mn red phosphor with a rod-like structure after drying. 4+ red phosphor.

2. The rod-shaped Na2SiF6:Mn red phosphor according to claim 1, characterized in that 4+ The rod-like structure Na2SiF6:Mn 4+ The red phosphor has a diameter length of 10 μm to 40 μm and an aspect ratio of (1.5-3):

1. ​ 3. The Na2SiF6:Mn red phosphor with a rod-like structure according to claim 2, characterized in that 4+ The rod-shaped structure Na2SiF6:Mn 4+ The red phosphor has a diameter length of 15 μm to 30 μm, and its aspect ratio is (2-3):

1. ​ 4. The rod-shaped Na2SiF6:Mn red phosphor according to any one of claims 1 to 3, characterized in that, 4+ The rod-shaped structure Na2SiF6:Mn 4+ The longest diameter of the longitudinal section of the red phosphor is D1, and the shortest diameter is D2, where 0.3 ≤ D2 / D1 ≤ 1; ​ Wherein, the plane where the longitudinal section is located is perpendicular to the length direction of the rod-shaped structure Na2SiF6:Mn 4+ red phosphor.

5. The Na2SiF6:Mn red phosphor with a rod-like structure according to claim 4, characterized in that 4+ 0.5 ≤ D2 / D1 ≤ 0.

8. ​ 6. The Na2SiF6:Mn red phosphor with a rod-like structure according to any one of claims 1 to 3, characterized in that 4+ The rod-shaped structure Na2SiF6:Mn 4+ red phosphor, with a peak wavelength of 627.1 nm under 455 nm excitation, and showing narrow-band emission with a full width at half maximum of the emission peak below 8 nm.

7. The rod-shaped Na2SiF6:Mn red phosphor according to claim 6, characterized in that 4+ , The rod-shaped structure Na2SiF6:Mn 4+ red phosphor, and its afterglow lifetime is from 3.6 ms to 5.5 ms.

8. The rod-shaped Na2SiF6:Mn red phosphor according to claim 1, characterized in that, 4+ The sum of the masses of the solid powders of Na2SiF6 and Na2MnF6 is W1, the mass of the hydrofluoric acid solution is W2, the mass of the solid powder of NaF is W3, the mass concentration of the hydrofluoric acid solution is 45 wt% to 55 wt%, and at least one of the following conditions is satisfied: ​ (1) 0.023 ≤ W1 / W2 ≤ 0.025; (2) 0.072 ≤ W3 / W2 ≤ 0.

08.

9. The rod-shaped Na2SiF6:Mn red phosphor according to claim 1, characterized in that 4+ In step (3), at least one of the following conditions is satisfied: ​ (1) The jet velocity of the first solution is V1, the jet velocity of the second solution is V2, 0.1 ≤ V1 / V2 ≤ 2; (2) The ambient temperature of the tube-flow reaction is below 0 °C, and the length of its tube channel is not less than 10 m; (3) The stirring speed is 30 rpm to 100 rpm, and the stirring time is 1.5 h to 2 h.

10. Application of the rod-shaped Na2SiF6:Mn red phosphor according to any one of claims 1 to 9 in an LED backlight source. 4+ ​ 11. An LED backlight source, characterized in that, The LED backlight includes an excitation chip and a phosphor coated on the excitation chip; The phosphor includes the rod-shaped Na2SiF6:Mn red phosphor according to any one of claims 1 to 9 4+ red phosphor 12. The LED backlight according to claim 11, wherein, At least one of the following conditions is satisfied: (1) The median particle size D50 of the phosphor is greater than 0.1 μm and less than 50 μm: (2) Based on the total mass of the phosphor, the mass percentage of the rod-shaped Na2SiF6:Mn 4+ red phosphor is higher than 30 wt%.

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