Mn 4+ Surface treatment method of activated fluoride phosphor, modified phosphor and application

Abstract

The application belongs to the technical field of red fluorescent powder materials for display, and particularly relates to Mn 4+ A surface treatment method of activated fluoride fluorescent powder, modified fluorescent powder and application. The method is to mix the activated fluoride fluorescent powder with an aqueous solution of aminotri (methylenephosphonic acid), stir and react, centrifugally collect the precipitate, wash with boiling water, dry to obtain a fluoride fluorescent powder precursor product; mix the precursor product with ethanol, stir, centrifugally collect the precipitate, wash and dry to obtain the surface-treated fluoride fluorescent powder. 4+ The activated fluoride fluorescent powder is mixed with an aqueous solution of aminotri (methylenephosphonic acid), stirred and reacted, centrifugally collected, washed with boiling water, dried to obtain a fluoride fluorescent powder precursor product; the precursor product is mixed with ethanol, stirred, centrifugally collected, washed and dried to obtain the surface-treated fluoride fluorescent powder. 4+ The activated fluoride fluorescent powder is mixed with an aqueous solution of aminotri (methylenephosphonic acid), stirred and reacted, centrifugally collected, washed with boiling water, dried to obtain a fluoride fluorescent powder precursor product; the precursor product is mixed with ethanol, stirred, centrifugally collected, washed and dried to obtain the surface-treated fluoride fluorescent powder. 2+ The activated fluoride fluorescent powder is mixed with an aqueous solution of aminotri (methylenephosphonic acid), stirred and reacted, centrifugally collected, washed with boiling water, dried to obtain a fluoride fluorescent powder precursor product; the precursor product is mixed with ethanol, stirred, centrifugally collected, washed and dried to obtain the surface-treated fluoride fluorescent powder. The KSFM fluorescent powder prepared in the application has good water resistance and light emitting characteristics, and has a wide application prospect.

Description

Technical Field

[0001] This invention belongs to the technical field of red phosphor materials for high color gamut backlight displays, specifically relating to a Mn 4+ Surface treatment methods for activated fluoride phosphors, modified phosphors and their applications. Background Technology

[0002] Mn 4+ Activated fluoride phosphors (such as A2MF6:Mn) 4+ Where A represents elements such as potassium, sodium, lithium, cesium, and rubidium, and M represents elements such as silicon, germanium, and titanium, due to the specific properties of Mn 4+ The intra-configurational transition properties of these phosphors have attracted considerable attention. These phosphors exhibit a broad absorption band in the blue light band and a narrow emission band in the red light band, with a stable emission peak wavelength around 630 nm. Fluoride phosphors are often used in combination with nitride green phosphors in backlight displays requiring high NTSC (NTSC ≥ 85%). Furthermore, these phosphors possess numerous advantages: low cost, simple room-temperature wet synthesis, excellent thermal stability, and superior luminescent performance including high luminous efficiency, high quantum efficiency, and high color purity. These characteristics make Mn... 4+ Activated fluoride phosphors have become an ideal choice for red phosphors in lighting and display applications. However, their practical application faces a key challenge—when exposed to humid environments, Mn... 4+ The ions undergo severe hydrolysis, resulting in poor water resistance. This defect must be addressed to truly unlock the potential of these materials in practical applications.

[0003] To improve Mn 4+ To improve the water resistance of activated fluoride phosphors, researchers have proposed various strategies. For example, inorganic coatings such as SiO2, Al2O3, and TiO2 are used to physically isolate the phosphor matrix from the humid environment. Meanwhile, organic compounds are also considered as candidate materials for constructing protective shells to improve moisture resistance. In existing technologies, reducing organic reagents such as organic acids are used to treat the fluoride surface; through their reducing power, adsorbed Mn can be removed from the surface. 4+ Ions, forming Mn-free or low-Mn groups on the phosphor surface 4+ The passivation layer forms a protective layer for the phosphor matrix. However, these reducing organic acids do not adsorb onto the phosphor surface, and the resulting passivation layer is usually thin and easily consumed during subsequent use, leading to a decrease in moisture resistance over time.

[0004] To further improve the moisture resistance of phosphors, some researchers have proposed adsorbing certain organic compounds onto the matrix surface to form a protective layer. For example, OAm (O-aminobenzoic acid) and PA (phthalic acid) can be adsorbed onto the matrix surface through their polar head groups (such as amino groups, NH3 groups, etc.). + or carboxylate, COO -Hydrogen bonds are formed between the organic coating and the fluorine-terminated groups of KSFM (potassium fluoride) phosphor, resulting in a strong adsorption onto the surface. However, promoting the formation of such hydrogen bonds usually requires pretreatment steps (such as ultraviolet irradiation or complex ethanol thermo-high pressure reaction treatment) to establish chemical bonding sites between the organic coating and the phosphor, which increases the complexity of the surface treatment process.

[0005] The inventor's previous patent CN120005607A disclosed a double-shell narrowband red phosphor, its preparation method, and its application. The surface of the double-shell narrowband red phosphor is free of Mn. 4+ The phosphor features a double-shell structure consisting of a potassium fluorosilicate inner shell and a hydrophobic cysteine ​​outer shell. This structure, covering the surface of the core narrowband red phosphor, significantly enhances its water resistance and luminescence properties. However, because the outermost shell is composed of organic matter, the organic coating is prone to aging under prolonged exposure to blue and ultraviolet light, affecting the stability of luminescence. Furthermore, under prolonged laser irradiation, when the local temperature exceeds 200°C, the organic matter on the phosphor surface decomposes, significantly reducing the phosphor's lifespan.

[0006] Therefore, developing new surface treatment methods remains crucial for improving the surface finish of Mn. 4+ The key to the luminescence stability of activated fluoride phosphors under extreme conditions. Summary of the Invention

[0007] To address the aforementioned problems, one objective of this invention is to provide a Mn 4+ A surface treatment method for activated fluoride phosphors is proposed to address the problems of poor stability and rapid decay of luminous efficiency of phosphors in high temperature and high humidity environments, thereby improving their application performance.

[0008] The technical solution adopted in this invention is as follows:

[0009] A type of Mn 4+ A surface treatment method for activated fluoride phosphors includes the following steps:

[0010] S1. Mix the fluoride phosphor to be treated with an aqueous solution of aminotrimethylenephosphonic acid. After the first stirring reaction, collect the precipitate by centrifugation.

[0011] S2. The collected precipitate was washed with boiling deionized water and dried to obtain the fluoride phosphor precursor product;

[0012] S3. The fluoride phosphor precursor product is mixed with ethanol, and after a second stirring reaction, the precipitate is collected by centrifugation, washed with deionized water, and dried to obtain the surface-treated fluoride phosphor.

[0013] Preferably, the Mn 4+The activated fluoride phosphor is A2MF6:Mn 4+ .

[0014] Preferably, the A2MF6:Mn 4+ In this context, A is an alkali metal cation selected from any one of K, Na, Li, Cs, and Rb, and M is a tetravalent metal cation selected from any one of Si, Ge, Ti, etc.

[0015] Preferably, the concentration of the aminotrimethylenephosphonic acid aqueous solution is 0.01~0.1wt%, and the molar ratio of the fluoride phosphor to be treated to aminotrimethylenephosphonic acid is 1:(10~100).

[0016] Preferably, the first stirring reaction is carried out in a sealed environment, and the stirring time is 2 hours.

[0017] Preferably, the second stirring reaction takes 30 minutes.

[0018] Preferably, in steps S2 and S3, the drying conditions are both 70°C for 2 hours.

[0019] Aminotrimethylenephosphonic acid (ATMP), a typical organophosphorus compound, is widely used as a chelating agent. The principle behind the ATMP modification in this application is that the ATMP molecule contains three phosphonic acid groups, giving it unique chemical reactivity: in oxidizing environments (such as those containing strong oxidizing agents like Mn), it reacts with these groups. 4+ When the CP bond in ATMP undergoes reductive cleavage, it triggers the reduction of the oxidant. This mechanism facilitates the formation of Mn-free phosphors on the KSFM phosphor surface. 4+ The passivation layer.

[0020] ;

[0021] Furthermore, hydrogen atoms in phosphonic acid groups can be replaced by transition metal ions through coordination, resulting in partial deprotonation. The transition metal ions act as bridging atoms, enabling the protonated phosphonic acid groups to assemble into a stable and dense network structure. This process facilitates the construction of dense organic-inorganic hybrid coatings on KSFM substrates.

[0022] ;

[0023] In this method, the reducing properties of the phosphonic acid groups in ATMP promote the formation of a potassium fluorosilicate (K2SiF6, or KSF) shell and the metastable intermediate degradation product IDMP. As the reduction process of KSFM progresses, IDMP-Mn is formed. 2+ In surface-bridging complexes, hydrogen atoms in phosphonic acid groups are coordinated with transition metal ions Mn through coordination. 2+The substitution process ultimately constructs a dense and transparent organic-inorganic hybrid outer shell. Meanwhile, unlike organic compounds such as cysteine ​​which only form hydrogen bonds with the internal F atoms, the organic-inorganic hybrid coating contains NH functional groups, which can form intermolecular hydrogen bonds with the internal KSF shell. Furthermore, the transition metal ions in the organic-inorganic hybrid coating can also form coordination bonds with KSF, further enhancing structural stability.

[0024] A second objective of this invention is to provide a modified phosphor, prepared using the surface treatment method described above, wherein the modified phosphor comprises Mn 4+ Activated fluoride phosphor and the Mn 4+ The outer shell of the activated fluoride phosphor; the shell is a double-layered shell, including a potassium fluorosilicate inner shell and an organic-inorganic hybrid Mn. 2+ Surface bridging composite shell layer Mn[HN(CH2PO3H)3].

[0025] Preferably, the inner shell layer has a thickness of 10-50 nm, the outer shell layer has a thickness of 5-20 nm, and the inner and outer shell layers are bonded together by hydrogen bonds and Mn. 2+ The coordinate bond is connected to the F coordinate bond in potassium fluorosilicate.

[0026] The third objective of this invention is to provide an application of the modified phosphor described above in the preparation of optoelectronic devices.

[0027] Preferably, the optoelectronic device includes a light-emitting diode lighting device and a laser lighting device, and the related devices can be used as backlight sources for novel high-brightness, high-color-gamut displays.

[0028] The fourth objective of this invention is to provide a light source product comprising the modified phosphor as described above.

[0029] The beneficial effects of this invention are as follows:

[0030] This application provides a surface treatment strategy based on ATMP, which is simple yet efficient. It enhances Mn doping by using the functional organic compound aminotris(methylphosphonic acid) (ATMP). 4+ The moisture resistance of potassium fluorosilicate (KSFM) phosphor was assessed. A specific chemical reaction occurred between ATMP and KSFM powder. Under this reaction, the CP bonds in ATMP underwent reduction and cleavage, promoting the formation of Mn-containing compounds on the KSFM surface. 4+ The defective K2SiF6 (KSF) inner shell, while the phosphonic acid groups in ATMP are transmitted through the transition metal ion Mn. 2+Coordination bridging was used to construct a dense and transparent organic-inorganic hybrid outer layer structure in the visible light range. Experiments showed that this hybrid outer layer structure has both good optical transparency and water barrier properties.

[0031] The phosphor prepared in this application has a double-shell structure on its surface—an inner shell containing K2SiF6 (KSF) and an outer dense organic-inorganic hybrid shell, which covers the surface of the core KSFM phosphor. This treatment significantly improves the water resistance and luminescence properties of the KSFM phosphor.

[0032] In existing technologies, many surface modification methods rely on simple physical adsorption to form coatings. However, the adhesion between the coating and the powder surface is weak, and the coating is easily detached under solvent immersion or external force, leading to a decrease in moisture resistance. For example, organic coatings prepared using OAM and pyruvic acid (PA) are directly adsorbed onto the phosphor surface, and the adsorption is of organic matter.

[0033] In this application, ATMP is not attached through physical adsorption, but rather serves solely as a reactant. It forms a dense organic-inorganic hybrid coating through a dual process of CP bond cleavage and reduction, and coordination bridging. This coating chemically bonds with KSFM powder to form a novel hybrid structure—an organic-inorganic hybrid outer layer (Mn[HN(CH2PO3H)3]). This hybrid outer layer exhibits excellent optical transparency in the visible light range (ensuring luminescence performance), is insoluble in water, and possesses extremely strong structural stability, remaining undecomposed at around 280℃. Furthermore, the molecular hydrogen bonds and coordination bonds formed between the hybrid outer layer and the inner shell further enhance the overall structure's resistance to detachment. This allows the ATMP-treated sample to maintain stable luminescence intensity even under extreme conditions such as boiling water immersion. Experimental and theoretical results indicate that the organic-inorganic hybrid outer layer (Mn[HN(CH2PO3H)3]) formed by the coating reaction simultaneously contains NH- and Mn-. 2+ Intermolecular hydrogen bonds are formed between the NH organic functional group and the inner KSF shell, while Mn 2+ Coordinate bonds can be formed with F atoms in the inner shell. These chemical bonds result in higher adsorption energy in the hybrid outer layer, which can more firmly and completely wrap around the surface of the inner KSF shell, while avoiding damage to the luminescent center of the inner KSFM. This gives KSFM phosphors significant resistance to damp heat and high luminescence efficiency. Attached Figure Description

[0034] Figure 1 XRD spectra of the prepared KSFM and KSFM-I powders.

[0035] Figure 2 The image shows the morphology of the prepared KSFM-I sample under a transmission electron microscope.

[0036] Figure 3 Fourier transform infrared (FTIR) spectral analysis of KSFM, KSFM-I, ATMP and IDMP samples.

[0037] Figure 4 XPS spectra of KSFM and KSFM-I samples.

[0038] Figure 5 The PLE and PL spectra of the prepared KSFM and KSFM-I are shown.

[0039] Figure 6 The moisture resistance of KSFM and KSFM-I after immersion in deionized water for different times was measured.

[0040] Figure 7 The luminous efficiency test results of KSFM and KSFM-I after being packaged into WLED1 (Figure (a)) and WLED2 (Figure (b)) materials.

[0041] Figure 8 This represents the offset of the color coordinates of WLED1 (Figure (a)) and WLED2 (Figure (b)) during the aging process.

[0042] Figure 9 This is a schematic diagram of the structure of the KSFM-YAG-sapphire composite film.

[0043] Figure 10 The changes in luminous flux of composite films prepared for KSFM and KSFM-I under laser excitation.

[0044] Figure 11 Color temperature changes of composite films prepared for KSFM and KSFM-I under laser excitation. Detailed Implementation

[0045] Unless otherwise stated, the terms used herein have the meanings commonly understood by those skilled in the art.

[0046] The technical solution of the present invention will be described in more detail below with reference to experiments:

[0047] 1. Chemicals and materials

[0048] Potassium permanganate (99.5%), potassium hydrofluoric acid (KHF2, 99%), hydrofluoric acid (HF, 49%), methanol (99.5%), ethanol (99%), nitrosotris(methylphosphonic acid) (ATMP, 50% aqueous solution), hydrogen peroxide (30%), and hexafluorosilicic acid (H2SiF6, 30-32%) were all purchased from McLean Chemical Reagent Co., Ltd. Deionized water was prepared in the laboratory.

[0049] K2MnF6 was synthesized using the Bode method.

[0050] In this experiment, Mn 4+ Activated fluoride phosphors were prepared using KSFM via a two-step precipitation method: 40 mmol of H₂SiF₆ was added to 30 ml of HF, and after the solution was thoroughly mixed, 0.5 g of K₂MnF₆ was added. After stirring for 30 minutes, a mixture of 8 g of KHF₂ and 30 ml of HF was added dropwise to the solution. After standing for half an hour, a yellow precipitate was separated by centrifugation, washed three times with ethanol, and dried at 70°C for 2 hours to obtain KSFM phosphor (0.05 MnF₆). 4+ ).

[0051] Prepare a methylphosphonic acid (ATMP) solution by dissolving 1 g of ATMP powder in 10-100 ml of deionized water.

[0052] 2. Mn 4+ Surface treatment method for activated fluoride phosphors

[0053] S1. Mix KSFM phosphor with 50% aminotrimethylenephosphonic acid aqueous solution at a molar ratio between 1:10 and 1:100, seal and stir for 2 hours, then centrifuge to collect the precipitate;

[0054] S2. The collected precipitate was washed with boiling deionized water and dried at 70°C for 2 hours to obtain the fluoride phosphor precursor product KSFM-I (0.05 Mn). 4+ ).

[0055] 3. Material Characterization

[0056] See Figure 1 -Figure 4. Figure 1 A representative KSFM (0.05 Mn) was demonstrated. 4+ The results of Rietveld refinement analysis of the powder XRD spectrum were presented. All observed diffraction peaks were in high agreement with the reference data of cubic K2SiF6 (space group Fm3m(225)) in PDF #75-0694, and no impurity characteristic peaks were observed. This confirms the successful synthesis of the expected pure-phase KSFM phosphor, and the KSFM sample (KSFM-I) treated with ATMP also remained in an impurity-free state.

[0057] Figure 2 This is a transmission electron microscope (TEM) image of the KSFM-I sample. It can be observed that the phosphor surface contains two shells, with the inner shell being approximately 40 nm and the outer shell approximately 4 nm.

[0058] Figure 3Fourier transform infrared (FTIR) spectral analysis of KSFM, KSFM-I, ATMP, and IDMP samples is presented. As shown in the figure, the FTIR spectrum of the KSFM sample did not reveal any absorption bands from organic functional groups. In contrast, the spectrum of KSFM-I showed absorption bands from methylene (-methylene), hydroxyl (OH), carbon-nitrogen (CN), and phosphorus-oxygen (PO) single bonds. Specifically, the absorption bands at 3060–2940, 2300, 1220, and 1040–900 cm⁻¹ correspond to the stretching vibrations of (-methylene), (OH), (CN), and (PO), respectively. These are characteristic vibrational modes of organophosphorus compounds, indicating that the outer shell is composed of organophosphorus compounds and successfully coated onto the phosphor surface. This outer shell not only improves the dispersibility of the material but also effectively suppresses Mn. 4+ Hydrolysis and oxidation in humid environments enhance the stability of phosphors.

[0059] Figure 4 The XPS spectrum of the sample clearly shows the characteristic signals of F, K, Si, and Mn elements. Furthermore, even after 50 cycles of dilution water rinsing, the XPS spectrum of the KSFM-I sample still detects signals of P, C, and N elements, strongly demonstrating the excellent stability of this organic coating in aqueous media. Further XPS analysis of the KSFM-I sample shows that even after rinsing with distilled water, Mn elements remain on the surface, and the final stability values ​​of nickel / manganese and phosphorus / manganese are approximately 1.2 and 3.2, respectively, indicating that the sample shell is a dense organic-inorganic hybrid Mn [HN(CH2PO3H)3]. This hybrid shell is anchored to the phosphor surface through strong coordination, effectively preventing the erosion of external water molecules and oxygen, and significantly improving the long-term stability of the material in humid environments.

[0060] 4. Luminescence and moisture-proof performance testing

[0061] 1) PLE and PL spectral testing

[0062] PLE and PL spectra of KSFM and KSFM-I samples were performed at room temperature. The results are shown in [link to relevant documentation]. Figure 5 The excitation peaks at 354 nm and 455 nm in the figure correspond to spin-allowed transitions, respectively. 4 A 2g → 4 T 1g and 4 A 2g → 4 T 2g The sharp PL emission peak observed in the 580-680 nm range is attributed to Mn. 4+ Spin-forbidden transitions 2 E g →4 A 2g The luminescence intensity of KSFM-I was significantly higher than that of KSFM, indicating that ATMP treatment improved the luminescence efficiency of the phosphor. The absorption efficiency (AE) and internal quantum efficiency (IQE) of the KSFM phosphor are detailed in Table 1 (by changing the amount of K2MnF6 added, the Mn content was adjusted). 4+ Doping concentration).

[0063] Table 1. Internal quantum yield and absorption efficiency of KSFM and KSFM-I under different manganese doping concentrations.

[0064] ;

[0065] It can be seen that the AE of KSFM-I is slightly lower than that of KSFM. This is attributed to the surface Mn of the fluoride sample after ATMP treatment. 4+ The content decreased. When the molar concentration of Mn was 5.00%, the IQE increased from 82.79% in untreated KSFM to 94.65% in KSFM-I.

[0066] 2) Moisture-proof performance test

[0067] Moisture resistance was tested after immersion in deionized water for different times. The specific test procedure was as follows: 0.2 g of each of KSFM and KSFM-I samples were placed in two cuvettes containing 5 ml of deionized water. Fluorescence intensity was measured using a spectrometer every 1 hour, and the powder color was recorded by photograph. The results are shown in [link to results]. Figure 6 The KSFM phosphor (top row of images) rapidly changed from yellow to brown within one hour. In contrast, the KSFM-I sample (bottom row of images) maintained its bright yellow color even after 8 hours of immersion in water, showing no significant change. This indicates that the processing method in this application improves the moisture resistance of the phosphor.

[0068] 3) Blue light-emitting diodes excite white LEDs

[0069] To evaluate the performance of LED packaged devices using KSFM phosphor after ATMP treatment, KSFM and KSFM-I phosphors were compared with commercial YAG:Ce 3+ White LEDs, denoted as WLED1 and WLED2, were fabricated by incorporating yellow phosphors onto a 455 nm blue light substrate.

[0070] To evaluate the stability of KSFM and KSFM-I phosphors, a 500-hour aging test was conducted under high temperature (85°C) and high humidity (85%) conditions.

[0071] The key optoelectronic parameters of the packaged white LED are summarized in Tables 2 and 3.

[0072] Table 2 Key photoelectric parameters of WLED1 during the aging process

[0073] ;

[0074] Table 3 Key photoelectric parameters of WLED2 during the aging process

[0075] ;

[0076] Figure 7 The luminous efficiency test results for WLED1 and WLED2 are shown. Figure 8 The color coordinate shift of WLED1 and WLED2 during the aging process is shown, with the shift amount located in the warm white light region.

[0077] See Figure 7 In (a), WLED1 (KSFM+YAG: Ce 3+ It exhibits a luminous efficacy of 121 lumens per watt at a drive current of 100 mA (correlated color temperature CCT = 3430 K, CRI = 84). For comparison, see [link to relevant documentation]. Figure 7 Middle (b), WLED2 (KSFM-I+ YAG: Ce 3+ It exhibits a high luminous efficiency of 130 lumens / watt (CCT = 3378 K, CRI = 86) under the same driving current.

[0078] See Figure 8 The color coordinates of WLED1 shifted significantly from (0.4084, 0.3904) to (0.3609, 0.3601), while WLED2 only showed a slight shift, with the color coordinates moving from (0.4108, 0.3904) to (0.3952, 0.3864).

[0079] Referring to Tables 2 and 3, during the aging process, the color coordinate of WLED1, using untreated KSFM red phosphor, continuously increased to 4475 K, while its luminous efficacy decreased from 121 lumens / watt to 102 lumens / watt. In contrast, WLED2, using KSFM-I phosphor, showed minimal fluctuations in color coordinate and luminous efficacy throughout the aging test. After 500 hours of aging, the CCT temperature rose to 3697 K, and the LE decreased from 130 to 124 lumens / watt. These small changes in CCT and LE of WLED2 indicate that ATMP treatment significantly improved the durability of KSFM phosphor under aging conditions.

[0080] 4) Fabrication and performance testing of white laser light-emitting diodes

[0081] 1. YAG slurry preparation:

[0082] Terpineol (solvent), ethyl 2-(2-butoxyethoxy)acetate (co-solvent), and ethyl cellulose (binder) were mixed in a ratio of 1:1:5 and stirred at 600 rpm for 24 hours at 80°C to prepare an organic carrier.

[0083] 2. Preparation of YAG-sapphire substrate

[0084] Commercial YAG:Ce:phosphor and low Tg glass powder were mixed in a 1:1 mass ratio, and an organic carrier (terpineol + ethyl cellulose) was added. The mixture was then ground into a homogeneous slurry. The YAG slurry was printed onto a CSA substrate (sapphire coated with an AR / BP layer) through a 250-mesh screen to form a YAG coating. The substrate was then sintered at 225°C for 10 minutes under a nitrogen atmosphere to obtain a YAG-sapphire substrate layer with a thickness of approximately 30 μm.

[0085] 3. KSFM Functional Layer Overlay

[0086] KSFM paste preparation: KSFM phosphor and glass powder are mixed at a ratio of 4:1 KtG (to optimize luminescence performance), and a high-viscosity printing paste is prepared using the same organic carrier as YAG paste.

[0087] Multi-layer printing: 1-5 layers of KSFM and KSFM-I paste are screen-printed on the YAG-sapphire substrate. Each layer is dried at room temperature for 10 minutes after printing, and the total thickness is controlled between 30 and 200 μm.

[0088] Sintering: The printed substrate is placed in a tube furnace and sintered at 225°C for 10 minutes under a nitrogen atmosphere. This melts the glass powder and coats the KSFM and KSFM-I phosphor particles, while preventing the formation of Mn. 4+ It is oxidized.

[0089] Cooling and post-processing: The film was naturally cooled to room temperature to obtain a dense KSFM-YAG-sapphire composite film.

[0090] The composite membrane structure after preparation is as follows Figure 9 As shown.

[0091] Blue laser light (441 nm) from a helium-cadmium laser is transmitted to a collimator via optical fiber. The light passes through a KSFM-YAG-sapphire composite film, which sequentially excites the YAG layer (yellow) and the KSFM layer (red). The two types of light mix with the residual blue light to form white light. By changing the laser input current, the laser output power is changed, and the changes in factors such as luminous flux and color temperature (CCT) are observed.

[0092] See Figure 10 As can be seen for the KSFM sample, when the laser energy density is greater than 3 W / mm² 2At this point, the luminous flux begins to drop sharply, indicating that the saturation limit of the KSFM sample has been reached. However, for the KSFM-I sample, even with a laser power close to 3 W / mm², the luminous flux continues to decrease. 2 At that time, the light flux of the sample can reach 450 lm. Obviously, under the excitation of high-power laser, the KSFM-I sample has better luminescence stability and more stable luminescence.

[0093] See Figure 11 When the incident power is fixed at 3W / mm 2 Under continuous laser irradiation, the color temperature of the laser light-emitting diode (LED) prepared by the KSFM sample increased from 3512K to 4603K, showing a significant drift. In contrast, the color temperature of the LED prepared by KSFM-I only increased from 3508K to 3698K. Due to localized overheating within the phosphor under continuous laser irradiation, the KSFM-I sample exhibited more stable luminescence and better timeliness, based on the color temperature drift observed in both samples.

[0094] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. M The surface treatment method for activating fluoride phosphors is characterized by, Includes the following steps: S1. The M to be processed Activated fluoride phosphor was mixed with an aqueous solution of aminotrimethylenephosphonic acid. After the first stirring reaction, the precipitate was collected by centrifugation. The M... The activated fluoride phosphor is A2MF6:Mn 4+ The A2MF6:Mn 4+ In this context, A is any one of K, Na, Li, Cs, and Rb, and M is any one of Si, Ge, and Ti. S2. The collected precipitate was washed with boiling deionized water and dried to obtain the fluoride phosphor precursor product; S3. The fluoride phosphor precursor product is mixed with ethanol, and after a second stirring reaction, the precipitate is collected by centrifugation, washed with deionized water, and dried to obtain the surface-treated fluoride phosphor.

2. The M as described in claim 1 The surface treatment method for activating fluoride phosphors is characterized by, The concentration of the aminotrimethylenephosphonic acid aqueous solution is 0.01~0.1wt%, and the molar ratio of the fluoride phosphor to be treated to aminotrimethylenephosphonic acid is 1:(10~100).

3. M as described in claim 1 The surface treatment method for activating fluoride phosphors is characterized by, The first stirring reaction was carried out in a sealed environment for 2 hours, and the second stirring reaction was carried out for 30 minutes.

4. M as described in claim 1 The surface treatment method for activating fluoride phosphors is characterized by, In steps S2 and S3 shown, the drying conditions are both 70°C for 2 hours.

5. A modified phosphor, characterized in that, The modified phosphor is prepared by the surface treatment method according to any one of claims 1-4, and the modified phosphor includes M. Activated fluoride phosphor and encapsulated in M The outer shell of the activated fluoride phosphor; the shell is a double-layered shell, including a potassium fluorosilicate inner shell and an organic-inorganic hybrid Mn. Surface bridging composite shell layer Mn[HN(CH2PO3H)3].

6. The modified phosphor as described in claim 5, characterized in that, The inner shell layer has a thickness of 10–50 nm, and the outer shell layer has a thickness of 5–20 nm. The inner and outer shell layers are bonded together by hydrogen bonds and Mn. The coordinate bond is connected to the F coordinate bond in potassium fluorosilicate.

7. The application of a modified phosphor as described in claim 5 or 6 in the preparation of optoelectronic devices, wherein the optoelectronic devices include light-emitting diode lighting devices and laser lighting devices.

8. A light source product, characterized in that, It contains the modified phosphor as described in claim 5 or 6.

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