Near ultraviolet excited red fluorescent powder for LED (light-emitting diode) as well as preparation method and application of near ultraviolet excited red fluorescent powder

Abstract

According to the near-ultraviolet excited red fluorescent powder for the LED and the preparation method, the precursor is obtained through coprecipitation, then the solid-phase reaction is carried out, and the near-ultraviolet excited red fluorescent powder for the LED is obtained, and the fluorescent powder prepared through the method is uniform in component and high in crystalline phase purity, luminescence quenching concentration and luminescence efficiency. The method is simple in process, conditions are easy to control, and special and expensive equipment is not needed; the preparation method has the advantages that the preparation process is simple, the yield is high, the repeatability is good, the pure-phase Zr < 1-2x > Nb < x > Eu < x > TiO4 micron-sized powder with higher luminance can be obtained, and the obtained Zr < 1-2x > Nb < x > Eu < x > TiO4 fluorescent powder can meet various application requirements, so that the Zr < 1-2x > Nb < x > Eu < x > TiO4 fluorescent powder can be widely applied to the fields of illumination, display, biomedicine and the like.

Description

Technical Field

[0001] The present application relates to the technical field of preparation and application of luminescent materials, and in particular to a red phosphor for near-ultraviolet excited LEDs, a preparation method and an application thereof. Background Art

[0002] White light LED has many advantages such as small size, low power consumption, long life, energy saving and environmental protection. It is a new generation of "green" light source and has important applications in lighting, display and other fields. Single-chip white light LED converted by fluorescent materials is the mainstream technical solution for achieving white light, including blue light chip technology (blue light chip + multi-color emitting phosphor) and ultraviolet / near-ultraviolet chip (ultraviolet / near-ultraviolet chip + multi-color emitting phosphor) technology. Fluorescent conversion material is one of the core materials of the device. Compared with blue light, ultraviolet / near-ultraviolet light can more effectively excite multi-color phosphors, and the matching of three primary color phosphors can more easily achieve high color rendering. It is of great significance to carry out research on near-ultraviolet excited phosphors. At present, high-performance red LED phosphors are still scarce and are one of the current research and development hotspots.

[0003] The earliest research and development of red phosphors was based on the white light LEDs formed by combining blue light LEDs and yellow YAG phosphors, which lacked red spectral components. However, due to various shortcomings of early red phosphors, as the efficiency of ultraviolet / near-ultraviolet LED chips increased, a large number of red phosphors were developed. Among them, there is Eu 2+ Ion-doped silicates, nitrides, sulfides, etc.; based on Eu 2+ -Mn 2+ Ion-doped phosphates, borates, halophosphates and silicates; based on Mn 4+ Doped fluoride, etc.; based on Eu 3+ Doped tungstates, molybdates, tungstates and molybdates and zirconium oxide, etc.

[0004] Eu 3+ is an important "traditional" red light emission center. In many matrices, the forced electric dipole transition within the 4f configuration ( 5 D0→ 7 F2) can produce a narrow band of intense red light in the range of 610-650nm; and in the near-purple region ( 5 D3, 5 L6, 5 D4, 5 G2← 7 F0 (360-410nm)) or blue light region also has characteristic absorption. 3+ The exploration of narrow-band red LED phosphors has never stopped.

[0005] ZrTiO4 has an α-PbO2 structure, exhibits excellent dielectric properties, high corrosion resistance and excellent temperature stability, and has good application prospects in microwave communications (as capacitors, dielectric resonators and oscillators in filters), optical devices, storage devices, photocatalysis and structural ceramics. ZrTiO4 is a suitable 3+ Activator-doped luminescent matrix; for example: Chinese patent (CN 202210325547.3), discloses a Zr-like 1-2x Nb x Eu x TiO4 red phosphor and preparation method, using ZrTiO4 as matrix, in realizing Eu 3+ The ion doping concentration is high while maintaining a relatively pure orthorhombic phase, which has bright Eu under near-ultraviolet light excitation (360-400nm) 3+ High color purity narrow band red light emission, suitable for near ultraviolet excitation LED. The invention discloses Zr prepared by high temperature solid phase method. 1-2x Nb x Eu x TiO4 phosphor is made by mixing some commercial oxide precursor powder raw materials (ZrO2, TiO2, Nb2O5, Eu2O3, etc.), and then calcining at high temperature. The high temperature drives the precursor raw material particles to diffuse and migrate, and then a chemical reaction occurs to generate the target Zr 1-2x Nb x Eu x TiO4 phosphor. Obviously, in the high-temperature solid-phase reaction method, the precursor particles are mixed at a scale of microns or above, and the reaction is difficult to proceed evenly, which can easily cause uneven distribution of activator concentration in the product grains and local enrichment of ions. This will induce phase separation, produce secondary phase impurities, and reduce the effective doping concentration. In addition, the enrichment of activators in the grains will enhance the energy transfer and migration between ions, reduce the luminescence quenching concentration, and ultimately reduce the luminescence intensity and efficiency. Therefore, it is urgent to study a method for preparing Zr 1-2x Tb x Eu x The co-precipitation wet chemical preparation method of O4 high-performance narrow-band red phosphor can maintain a relatively pure crystalline phase while achieving high doping concentration. Summary of the invention

[0006] In view of this, the present application provides a near-ultraviolet excited red phosphor for LED, a preparation method and an application thereof, in order to solve the existing high temperature solid phase method for preparing Zr 1-2x Nb x Eu x TiO4 phosphor has technical problems such as uneven distribution of powder components, large particle size and severe agglomeration.

[0007] To solve the above problems, this application adopts the following technical solutions:

[0008] One of the purposes of the present application is to provide a method for preparing a near-ultraviolet excited LED red phosphor, wherein the chemical formula of the near-ultraviolet excited LED red phosphor is Zr 1-2x Nb x Eu x TiO4; wherein 0.01≤x≤0.24, comprising the following steps:

[0009] Adding Zr source, Ti source, Eu source and Nb source in deionized water in stoichiometric ratio to form a transparent solution;

[0010] Adding ammonia water precipitant dropwise to the transparent solution until a suspension of milky white precipitate is generated;

[0011] subjecting the suspension to an aging treatment;

[0012] The aged suspension is subjected to solid-liquid separation, washed, and dried to obtain a precursor;

[0013] The near-ultraviolet excited red phosphor for LED is obtained by high-temperature treatment of the precursor.

[0014] In some of the embodiments, in the step of sequentially adding a Zr source, a Ti source, a Eu source and a Nb source to deionized water to form a transparent solution, the Zr source is at least one or more of Zr(SO4)2, Zr(NO3)4 or ZrOCl2 or their hydrates; the Ti source is Ti(SO4)2 or its hydrate; the Eu source is at least one or more of Eu(NO3)3, EuCl3 or their hydrates; and the Nb source is at least one or two of ammonium niobate oxalate hydrate and hydrated niobium oxalate.

[0015] In some embodiments, Ti in the transparent solution 4+ The molar concentration is 0.2~1.0mol / L.

[0016] In some embodiments, in the step of titrating an ammonia precipitant into the transparent solution until a suspension of a milky white precipitate is generated, the molar ratio of NH3 to the red phosphor for LED in the ammonia precipitant is about 2.1 to 8.1.

[0017] In some embodiments, in the step of adding ammonia water precipitant to the transparent solution until a suspension of milky white precipitate is generated, the titration rate is 1-8 mL / min.

[0018] In some embodiments, in the step of aging the suspension, the aging time is 8 to 12 hours.

[0019] In some of the embodiments, in the step of obtaining the near-ultraviolet excited LED red phosphor after high-temperature treatment of the precursor, the high-temperature treatment is high-temperature calcination, the calcination temperature is 1200-1400° C., and the calcination time is 4-6 hours.

[0020] The second purpose of the present application is to provide a red phosphor for near-ultraviolet excited LED, which is prepared by the preparation method of the red phosphor for near-ultraviolet excited LED.

[0021] The third purpose of the present application is to provide an application of the near-ultraviolet excited LED red phosphor in a light-emitting device.

[0022] This application adopts the above technical solution, and its beneficial effects are as follows:

[0023] The present application provides a near-ultraviolet excited LED red phosphor and a preparation method, wherein a precursor is obtained by coprecipitation, and then a solid phase reaction is performed to obtain the near-ultraviolet excited LED red phosphor. The phosphor prepared by the present application using the method has uniform components, high crystal phase purity, high luminescence quenching concentration and high luminescence efficiency. The method has a simple process, easy control of conditions, and does not require special expensive equipment; it has a high yield and good repeatability, and can obtain pure phase Zr with high luminescence brightness. 1-2x Nb x Eu x TiO4 micron powder, obtained Zr 1-2x Nb x Eu x TiO4 phosphor can meet a variety of application requirements, making it widely used in lighting, display, biomedicine and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 A flow chart of the steps of a method for preparing red phosphor for near-ultraviolet excited LEDs provided in an embodiment of the present application.

[0026] Figure 2 is Zr in Example 1 0.56 Nb 0.22 Eu 0.22 TiO4, Zr in Example 2 0.96 Nb 0.02 Eu0.02 TiO4, Zr in Example 3 0.88 Nb 0.06 Eu 0.06 TiO4, Zr in Example 5 0.72 Nb 0.14 Eu 0.14 TiO4, Zr in Example 7 0.60 Nb 0.20 Eu 0.20 TiO4, Zr in Example 8 0.52 Nb 0.24 Eu 0.24 XRD diffraction pattern of TiO4 and standard card pattern of orthorhombic phase ZrTiO4 (PDF#74-1504).

[0027] Figure 3 is Zr in Example 1 0.56 Nb 0.22 Eu 0.22 TiO4, Zr in Example 2 0.96 Nb 0.02 Eu 0.02 TiO4, Zr in Example 3 0.88 Nb 0.06 Eu 0.06 TiO4, Zr in Example 5 0.72 Nb 0.14 Eu 0.14 TiO4, Zr in Example 6 0.64 Nb 0.18 Eu 0.18 TiO4, Zr in Example 8 0.52 Nb 0.24 Eu 0.24 SEM image of TiO4.

[0028] Figure 4 is Zr in Example 1 0.56 Nb 0.22 Eu 0.22 TiO4, Zr in Example 2 0.96 Nb 0.02 Eu 0.02 TiO4, Zr in Example 3 0.88 Nb 0.06 Eu 0.06 TiO4, Zr in Example 4 0.80 Nb 0.10 Eu 0.10 TiO4, Zr in Example 5 0.72 Nb 0.14 Eu 0.14 TiO4, Zr in Example 6 0.64 Nb 0.18Eu 0.18 TiO4, Zr in Example 8 0.52 Nb 0.24 Eu 0.24 Excitation spectrum of TiO4, monitoring emission wavelength is 613nm.

[0029] Figure 5 is Zr in Example 1 0.56 Nb 0.22 Eu 0.22 TiO4, Zr in Example 2 0.96 Nb 0.02 Eu 0.02 TiO4, Zr in Example 3 0.88 Nb 0.06 Eu 0.06 TiO4, Zr in Example 4 0.80 Nb 0.10 Eu 0.10 TiO4, Zr in Example 5 0.72 Nb 0.14 Eu 0.14 TiO4, Zr in Example 6 0.64 Nb 0.18 Eu 0.18 TiO4, Zr in Example 8 0.52 Nb 0.24 Eu 0.24 The emission spectrum of TiO4 has an excitation wavelength of 393nm.

[0030] Figure 6 In order to utilize Zr in Example 1 of the present invention 0.56 Nb 0.22 Eu 0.22 TiO4, blue phosphor Sr5(PO4)3Cl:Eu 2+ and green phosphor (Ba,Sr)SiO4:Eu 2+ The electroluminescence spectrum of the white light emitting LED packaged with a near-ultraviolet chip (395-400nm) (working current 20mA) and the luminescence photo of the LED working in a dark environment.

[0031] Figure 7 In order to utilize Zr in Example 4 of the present invention 0.80 Nb 0.10 Eu 0.10 XRD diffraction patterns of TiO4, the product in Comparative Example 1 and the product in Comparative Example 2, and the standard card pattern of orthorhombic phase ZrTiO4 (PDF#74-1504).

[0032] Figure 8 In order to utilize Zr in Example 4 of the present invention 0.80 Nb 0.10 Eu0.10 The emission spectra of TiO4, the product in Comparative Example 1 and the product in Comparative Example 2 have an excitation wavelength of 393 nm. DETAILED DESCRIPTION

[0033] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0034] In the description of the present application, it should be understood that the terms "upper", "lower", "horizontal", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0035] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0036] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0037] See also Figure 1 , is a flow chart of the steps of the method for preparing the near-ultraviolet excited LED red phosphor provided in the embodiment of the present application. The chemical formula of the near-ultraviolet excited LED red phosphor prepared in the present application is Zr 1-2x Nb x Eu x TiO4; wherein, 0.01≤x≤0.24, the amounts of related substances in the following steps are provided according to the above chemical formula, specifically including the following steps S110 to S150, and the implementation method of each step is described in detail below.

[0038] Step S110: adding a Zr source, a Ti source, a Eu source and a Nb source in sequence according to a stoichiometric ratio into deionized water to form a transparent solution.

[0039] In this embodiment, a Zr source is added to deionized water and stirred to obtain a first solution; a Ti source is added to the first solution and stirred to obtain a second solution; a Eu source is added to the second solution and stirred to obtain a third solution; a Nb source is added to the third solution and stirred to obtain a fourth solution, and the above-mentioned solutions can be obtained.

[0040] Furthermore, in the above solution, Ti 4+ The molar concentration is 0.2~1.0mol / L.

[0041] In this embodiment, the Zr source is at least one or more of Zr(SO4)2, Zr(NO3)4 or ZrOCl2 or their hydrates; the Ti source is Ti(SO4)2 or its hydrates; the Eu source is at least one or more of Eu(NO3)3, EuCl3 or their hydrates; the Nb source is at least one or two of ammonium niobate oxalate hydrate and hydrated niobium oxalate.

[0042] Step S120: adding ammonia water precipitant to the solution until a suspension of milky white precipitate is generated.

[0043] In this embodiment, in the ammonia precipitation agent, the molar ratio of NH3 to the red phosphor to be prepared for LED is about 2.1-8.1, and the titration rate is 1-8 mL / min.

[0044] Step S130: subjecting the suspension of the milky white precipitate to aging treatment.

[0045] Furthermore, the aging time is 8 to 12 hours.

[0046] Step S140: washing and drying the aged milky white precipitate suspension to obtain a precursor.

[0047] In this embodiment, the step of performing solid-liquid separation, washing and drying the aged milky white precipitate suspension to obtain a precursor specifically includes the following steps: washing the aged milky white precipitate suspension once with deionized water, then washing twice with ethanol, and then drying the washed precipitate at a temperature of 60 to 100°C to obtain a precursor.

[0048] In this example, orthorhombic Zr was prepared by coprecipitation method. 1-2x Nb x Eu xTiO4 precursor, adding a precipitant to the mixed metal salt solution to precipitate one or more cations contained in the solution together to generate a precipitation mixture or a solid solution precursor, and then filtering, washing, and thermally decomposing to obtain a composite oxide method, which is characterized in that the precursor raw materials used are dissolved in the solution, and uniform mixing at the ion / molecular level can be achieved. Through various chemical reactions in the solution, a solid solution is formed between the components, so that the dispersion and uniformity of the material are significantly improved, and then a powder material with uniform chemical composition is obtained, which can make the dispersion and uniformity of the prepared material better, which is one of its biggest advantages over solid phase mixing methods, etc.; This embodiment uses the coprecipitation method to prepare orthorhombic Zr 1-2x Nb x Eu x TiO4 precursor, based on the characteristics of co-precipitation method, can be used to prepare Zr 1-2x Nb x Eu x The metal ions required for the TiO4 precursor are uniformly mixed at the ion level in the solution, which overcomes the problem that in the high-temperature solid-phase reaction method, the precursor particles are mixed at a scale of microns or above, the reaction is difficult to proceed uniformly, and it is easy to cause uneven distribution of activator concentration in the product grains and local ion enrichment and aggregation. In addition, the coprecipitation method in this embodiment prepares the orthorhombic Zr 1-2x Nb x Eu x TiO4 precursor, with the help of various chemical reactions in the solution, can obtain precursor powder materials with uniform chemical composition, which is beneficial to high temperature calcination of Zr 1-2x Nb x Eu x The formation of high-purity TiO4 crystal phase reduces the solid phase reaction temperature and time.

[0049] Step S150: subjecting the precursor to high-temperature treatment to obtain the near-ultraviolet excited LED red phosphor.

[0050] In this embodiment, in the step of obtaining the near-ultraviolet excited LED red phosphor after high-temperature treatment of the precursor, the high-temperature treatment is high-temperature calcination, the calcination temperature is 1200-1400° C., and the calcination time is 4-6 hours.

[0051] It can be understood that the coprecipitation-solid phase method used in this embodiment can inhibit the aggregation of doped ions and make the prepared Zr 1-2x Nb x Eu x The matrix components and doping ions of TiO4 phosphor are evenly distributed, which improves Eu 3+ The prepared phosphor has small particle size, narrow size distribution, high crystallinity and high luminescence brightness.

[0052] The present application provides a near-ultraviolet excited LED red phosphor and a preparation method, wherein a precursor is obtained by coprecipitation, and then a solid phase reaction is performed to obtain the near-ultraviolet excited LED red phosphor. The phosphor prepared by the present application using the method has uniform components, high crystal phase purity, high luminescence quenching concentration and high luminescence efficiency. The method has a simple process, easy control of conditions, and does not require special expensive equipment; it has a high yield and good repeatability, and can obtain pure phase Zr with high luminescence brightness. 1-2x Nb x Eu x TiO4 micron powder, obtained Zr 1-2x Nb x Eu x TiO4 phosphor can meet a variety of application requirements, making it widely used in lighting, display, biomedicine and other fields.

[0053] The following further describes the luminescent nanocrystalline material of the present application and its preparation method and application with specific examples. This section further describes the content of the present invention in conjunction with specific examples, but should not be construed as limiting the present invention. Unless otherwise specified, the technical means adopted in the embodiments are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0054] Example 1

[0055] This embodiment provides a chemical formula of Zr 0.56 Nb 0.22 Eu 0.22 The method for preparing a red phosphor material of TiO4 comprises the following steps:

[0056] S1, according to the chemical formula Zr 0.56 Nb 0.22 Eu 0.22 TiO4, weigh 1.9902g Zr(SO4)2·6H2O, dissolve in 30ml deionized water under magnetic stirring, continue magnetic stirring for 10min, and obtain the first solution;

[0057] S2, according to the chemical formula Zr 0.56 Nb 0.22 Eu 0.22 TiO4, weigh 2.3999g Ti(SO4)2, dissolve it in the first solution under magnetic stirring, continue magnetic stirring for 10 minutes to obtain a second solution;

[0058] S3, according to the chemical formula Zr 0.56 Nb 0.22 Eu 0.22TiO4, weigh 0.9813g Eu(NO3)3·6H2O, dissolve in the second solution under magnetic stirring, continue magnetic stirring for 10min, and obtain the third solution;

[0059] S4, according to the chemical formula Zr 0.56 Nb 0.22 Eu 0.22 TiO4, weigh 0.6665 g of ammonium niobate oxalate hydrate (C4H4NNbO9·xH2O), dissolve in the third solution under magnetic stirring, and continue magnetic stirring for 10 minutes to obtain a fourth solution;

[0060] S5. Under magnetic stirring conditions, dissolve 10 mL of aqueous ammonia (NH3 concentration is 25-28%) in 90 mL of deionized water, stir, and continue magnetic stirring for 10 min to obtain a fifth solution;

[0061] S6. Under magnetic stirring conditions, slowly titrate the fourth solution into the fifth solution, stirring continuously during titration, causing a coprecipitation reaction to occur, generating a milky white precipitate, and aging for 10 hours after the titration is completed;

[0062] S7, centrifugally separating the aged precipitate suspension and washing it with deionized water to obtain a white precipitate precursor;

[0063] S8, washing the obtained white precipitate once with deionized water and then centrifuging, then washing twice with ethanol and then centrifuging, and drying at 60° C. for 12 h to obtain a dry precursor;

[0064] S9. Place the above precursor into a high-purity corundum crucible and keep it at 1300° C. for 4 hours in air to obtain a red phosphor material.

[0065] Example 2

[0066] Example 2 provides a chemical formula of Zr 0.96 Nb 0.02 Eu 0.02 The preparation method of TiO4 red phosphor comprises: measuring a certain mass of Zr(SO4)2, Ti(SO4)2, Eu(NO3)3·6H2O, and ammonium niobate oxalate hydrate (C4H4NNbO9·xH2O) according to a stoichiometric ratio to satisfy the stoichiometric ratio; other preparation process control conditions such as magnetic stirring time, raw material addition sequence, aging time, drying temperature and time, washing method, etc. are the same as those in Example 1.

[0067] Example 3

[0068] Example 3 provides a chemical formula of Zr 0.88 Nb 0.06 Eu 0.06The preparation method of TiO4 red phosphor comprises: measuring a certain mass of Zr(SO4)2, Ti(SO4)2, Eu(NO3)3·6H2O, and ammonium niobate oxalate hydrate (C4H4NNbO9·xH2O) according to a stoichiometric ratio to satisfy the stoichiometric ratio; other preparation process control conditions such as magnetic stirring time, raw material addition sequence, aging time, drying temperature and time, washing method, etc. are the same as those in Example 1.

[0069] Example 4

[0070] Example 4 provides a chemical formula of Zr 0.80 Nb 0.10 Eu 0.10 The preparation method of TiO4 red phosphor comprises: measuring a certain mass of Zr(SO4)2, Ti(SO4)2, Eu(NO3)3·6H2O, and ammonium niobate oxalate hydrate (C4H4NNbO9·xH2O) according to a stoichiometric ratio to satisfy the stoichiometric ratio; other preparation process control conditions such as magnetic stirring time, raw material addition sequence, aging time, drying temperature and time, washing method, etc. are the same as those in Example 1.

[0071] Example 5

[0072] Example 5 provides a chemical formula of Zr 0.72 Nb 0.14 Eu 0.14 The preparation method of TiO4 red phosphor comprises: measuring a certain mass of Zr(SO4)2, Ti(SO4)2, Eu(NO3)3·6H2O, and ammonium niobate oxalate hydrate (C4H4NNbO9·xH2O) according to a stoichiometric ratio to satisfy the stoichiometric ratio; other preparation process control conditions such as magnetic stirring time, raw material addition sequence, aging time, drying temperature and time, washing method, etc. are the same as those in Example 1.

[0073] Example 6

[0074] Example 6 provides a chemical formula of Zr 0.64 Nb 0.18 Eu 0.18 The preparation method of TiO4 red phosphor comprises: measuring a certain mass of Zr(SO4)2, Ti(SO4)2, Eu(NO3)3·6H2O, and ammonium niobate oxalate hydrate (C4H4NNbO9·xH2O) according to a stoichiometric ratio to satisfy the stoichiometric ratio; other preparation process control conditions such as magnetic stirring time, raw material addition sequence, aging time, drying temperature and time, washing method, etc. are the same as those in Example 1.

[0075] Example 7

[0076] Example 7 provides a chemical formula of Zr0.60 Nb 0.20 Eu 0.20 The preparation method of TiO4 red phosphor comprises: measuring a certain mass of Zr(SO4)2, Ti(SO4)2, Eu(NO3)3·6H2O, and ammonium niobate oxalate hydrate (C4H4NNbO9·xH2O) according to a stoichiometric ratio to satisfy the stoichiometric ratio; other preparation process control conditions such as magnetic stirring time, raw material addition sequence, aging time, drying temperature and time, washing method, etc. are the same as those in Example 1.

[0077] Example 8

[0078] Example 8 provides a chemical formula of Zr 0.52 Nb 0.24 Eu 0.24 The preparation method of TiO4 red phosphor comprises: measuring a certain mass of Zr(SO4)2, Ti(SO4)2, Eu(NO3)3·6H2O, and ammonium niobate oxalate hydrate (C4H4NNbO9·xH2O) according to a stoichiometric ratio to satisfy the stoichiometric ratio; other preparation process control conditions such as magnetic stirring time, raw material addition sequence, aging time, drying temperature and time, washing method, etc. are the same as those in Example 1.

[0079] Example 9

[0080] Example 9 provides a chemical formula of Zr 0.80 Nb 0.10 Eu 0.10 The preparation method of TiO4 red phosphor comprises: measuring a certain mass of Zr(NO3)4, Ti(SO4)2, Eu(NO3)3·6H2O, and ammonium niobate oxalate hydrate (C4H4NNbO9·xH2O) according to a stoichiometric ratio to satisfy the stoichiometric ratio; other preparation process control conditions such as magnetic stirring time, raw material addition sequence, aging time, drying temperature and time, washing method, etc. are the same as those in Example 1.

[0081] Example 10

[0082] Example 10 provides a chemical formula of Zr 0.80 Nb 0.10 Eu 0.10 The preparation method of TiO4 red phosphor comprises: measuring a certain mass of ZrOCl2, Ti(SO4)2, Eu(NO3)3·6H2O, and ammonium niobate oxalate hydrate (C4H4NNbO9·xH2O) according to a stoichiometric ratio to satisfy the stoichiometric ratio; other preparation process control conditions such as magnetic stirring time, raw material addition sequence, aging time, drying temperature and time, washing method, etc. are the same as those in Example 1.

[0083] Embodiment 11

[0084] Example 11 provides a chemical formula of Zr 0.80 Nb 0.10 Eu 0.10 The preparation method of TiO4 red phosphor comprises: taking a certain mass of Zr(SO4)2, Ti(SO4)2, EuCl3·6H2O, hydrated niobium oxalate (C 10 H5B 20 ·xH2O) to satisfy the stoichiometric ratio; other preparation process control conditions such as magnetic stirring time, raw material addition sequence, aging time, drying temperature and time, washing method, etc. are the same as those in Example 1.

[0085] Comparative Example 1

[0086] Comparative Example 1 provides a method for preparing a red phosphor, comprising: measuring a certain mass of Zr(SO4)2, Ti(SO4)2, Eu(NO3)3·6H2O, and ammonium niobate oxalate hydrate (C4H4NNbO9·xH2O) in a stoichiometric ratio to satisfy the stoichiometric ratio; in step S5 of the preparation process of comparative column 1, weighing 11.859g NH4HCO3 in 100mL deionized water, stirring, and adding 150ml ethanol after it becomes clear and transparent, and continuing magnetic stirring for 10min to obtain a fifth solution. Except for step S5, other preparation process controls such as magnetic stirring time, raw material addition order, aging time, drying temperature and time, washing method and other conditions are the same as those in Example 1.

[0087] Comparative Example 2

[0088] Comparative Example 2 provides a method for preparing a red phosphor, comprising: measuring a certain mass of Zr(SO4)2, Ti(SO4)2, Eu(NO3)3, and ammonium niobate oxalate hydrate (C4H4NNbO9·xH2O) in a stoichiometric ratio to satisfy the stoichiometric ratio; weighing 11.859 g of NH4HCO3 in 100 mL of deionized water in step S5 of the preparation process of Comparative Example 2, stirring, and adding 150 mL of ethanol after it becomes clear and transparent, and then adding 5 mL of ammonia water, and continuing magnetic stirring for 10 minutes to obtain a fifth solution. Except that the fifth solution in step S5 is different, other preparation process controls such as magnetic stirring time, raw material addition order, aging time, drying temperature and time, washing method and other conditions are the same as those in Example 1.

[0089] In Example 1, Zr 0.56 Nb 0.22 Eu 0.22 TiO4, Zr in Example 2 0.96 Nb 0.02 Eu 0.02TiO4, Zr in Example 3 0.88 Nb 0.06 Eu 0.06 TiO4, Zr in Example 4 0.80 Nb 0.10 Eu 0.10 TiO4, Zr in Example 5 0.72 Nb 0.14 Eu 0.14 TiO4, Zr in Example 6 0.64 Nb 0.18 Eu 0.18 TiO4, Zr in Example 7 0.60 Nb 0.20 Eu 0.20 TiO4, Zr in Example 8 0.52 Nb 0.24 Eu 0.24 TiO4, Zr in Example 9 0.80 Nb 0.10 Eu 0.10 TiO4, Zr in Example 10 0.80 Nb 0.10 Eu 0.10 TiO4, Zr in Example 11 0.80 Nb 0.10 Eu 0.10 The properties of TiO4, the product in Comparative Example 1 and the product in Comparative Example 2 are shown in the attached Figures 1 to 7 .

[0090] Performance Testing

[0091] Figure 2 is Zr in Example 1 0.56 Nb 0.22 Eu 0.22 TiO4, Zr in Example 2 0.96 Nb 0.02 Eu 0.02 TiO4, Zr in Example 3 0.88 Nb 0.06 Eu 0.06 TiO4, Zr in Example 5 0.72 Nb 0.14 Eu 0.14 TiO4, Zr in Example 7 0.60 Nb 0.20 Eu 0.20 TiO4, Zr in Example 8 0.52 Nb 0.24 Eu 0.24 XRD diffraction pattern of TiO4 and standard card pattern of orthorhombic phase ZrTiO4 (PDF#74-1504). Figure 1It can be seen that in the matrix lattice, Nb 5+ Replace Zr 4+ / Ti 4+ Produces local positive charge, and Eu 3+ Unequivalent substitution of Zr 4+ / Ti 4+ The local negative charge is generated, and the two compensate each other to achieve charge balance, realizing compensatory avalent substitution (i.e., 2Zr 4+ / Ti 4+ →Nb 5+ +Eu 3+ ), reducing the generation of defects such as oxygen vacancies. 3+ With Nb 5+ When the doping concentration is low, no obvious impurity peak is observed, such as Zr in Example 2. 0.96 Nb 0.02 Eu 0.02 The XRD diffraction peaks of TiO4 are almost consistent with the orthorhombic ZrTiO4 standard card (PDF#74-1504). When the doping concentration is high, some impurity peaks begin to appear, such as Zr in Example 5. 0.72 Nb 0.14 Eu 0.14 TiO4, initially believed to be trace amounts of Zr5Ti7O 24 In Example 4, Zr 0.80 Nb 0.10 Eu 0.10 TiO4, Zr in Example 6 0.64 Nb 0.18 Eu 0.18 TiO4, Zr in Example 9 0.80 Nb 0.10 Eu 0.10 TiO4, Zr in Example 10 0.80 Nb 0.10 Eu 0.10 TiO4 and Zr in Example 11 0.80 Nb 0.10 Eu 0.10 TiO4 and Zr in Example 4 0.80 Nb 0.10 Eu 0.10 The XRD diffraction pattern of TiO4 is similar. The main crystal phase of the material is orthorhombic zirconium titanate, and the space group is Pbcn. No further illustration is provided here for further explanation.

[0092] Figure 3 is Zr in Example 1 0.56 Nb 0.22 Eu 0.22 TiO4, Zr in Example 2 0.96 Nb 0.02 Eu 0.02TiO4, Zr in Example 3 0.88 Nb 0.06 Eu 0.06 TiO4, Zr in Example 5 0.72 Nb 0.14 Eu 0.14 TiO4, Zr in Example 6 0.64 Nb 0.18 Eu 0.18 TiO4 and Zr in Example 8 0.52 Nb 0.24 Eu 0.24 SEM image of TiO4. Figure 2 It can be seen that in Example 2, Zr 0.96 Nb 0.02 Eu 0.02 The particle morphology of TiO4 is irregular. 5+ / Eu 3+ With the increase of doping concentration, the size of individual particles does not change much, but the hinge agglomeration between particles increases. 0.80 Nb 0.10 Eu 0.10 TiO4, Zr in Example 7 0.60 Nb 0.20 Eu 0.20 TiO4, Zr in Example 9 0.80 Nb 0.10 Eu 0.10 TiO4, Zr in Example 10 0.80 Nb 0.10 Eu 0.10 TiO4 and Zr in Example 11 0.80 Tb 0.10 Eu 0.10 O4 and Zr in Example 1 0.80 Nb 0.10 Eu 0.10 The SEM image of TiO4 is similar and is not shown here for further explanation.

[0093] Figure 4 is Zr in Example 1 0.56 Nb 0.22 Eu 0.22 TiO4, Zr in Example 2 0.96 Nb 0.02 Eu 0.02 TiO4, Zr in Example 3 0.88 Nb 0.06 Eu 0.06 TiO4, Zr in Example 4 0.80 Nb 0.10 Eu 0.10 TiO4, Zr in Example 50.72 Nb 0.14 Eu 0.14 TiO4, Zr in Example 6 0.64 Nb 0.18 Eu 0.18 TiO4 and Zr in Example 8 0.52 Nb 0.24 Eu 0.24 The excitation spectrum of TiO4 was monitored at 613nm. Figure 4 It can be seen from the figure that the excitation spectrum in the embodiment contains two overlapping broad and strong bands and some sharp lines. The broad band excitation originates from the energy to Eu 3+ Energy transfer O 2- →Ti 4+ and O 2- →Nb 5+ Charge transfer excitation, spectrum covers ultraviolet to near ultraviolet region (~225-400nm). 2- →Nb 5+ The charge transfer broadband excitation peak is located at ~340nm, extending to the near-ultraviolet region, and further 3+ The 4f-4f sharp line ( 5 D4← 7 F0, 5 G2← 7 F0, 5 L6← 7 F0, 5 D3← 7 F0) excitation phase superposition. For isolated niobate, O 2- →Nb 5+ The charge transfer excitation broadband peak is usually located in the spectral range of ﹤300nm. Here, Nb 5+ The formation of clusters between the excited state electrons and the enhanced delocalization of the excited state electrons make O 2- →Nb 5+ The charge transfer excitation band is significantly red-shifted. 5+ -Eu 3+ The coupling between them forms heterogeneous ion clusters, which enhances the 5+ The 5d orbital of Eu 3+ The 4f electron wave function is disturbed, and the anti-parity state mixing relaxes the 4f-4f transition selection rule, increases the oscillator strength, and improves the excitation efficiency, resulting in stronger 4f-4f sharp line excitation. 0.60 Nb 0.20 Eu 0.20 TiO4, Zr in Example 9 0.80 Nb 0.10 Eu 0.10 TiO4, Zr in Example 10 0.80 Nb0.10 Eu 0.10 TiO4 and Zr in Example 11 0.80 Tb 0.10 Eu 0.10 O4 and Zr in Example 1 0.80 Nb 0.10 Eu 0.10 The excitation spectrum of TiO4 is similar and is not illustrated here.

[0094] Figure 5 is Zr in Example 1 0.56 Nb 0.22 Eu 0.22 TiO4, Zr in Example 2 0.96 Nb 0.02 Eu 0.02 TiO4, Zr in Example 3 0.88 Nb 0.06 Eu 0.06 TiO4, Zr in Example 4 0.80 Nb 0.10 Eu 0.10 TiO4, Zr in Example 5 0.72 Nb 0.14 Eu 0.14 TiO4, Zr in Example 6 0.64 Nb 0.18 Eu 0.18 TiO4 and Zr in Example 8 0.52 Nb 0.24 Eu 0.24 The emission spectrum of TiO4 has an excitation wavelength of 393nm. Figure 5 As can be seen from the figure, the embodiment emits a strong narrow-band high-color-purity red visible light, with a main peak at ~613nm and a half-height width of ~5nm, which is derived from Eu 3+ of 5 D0→ 7 F2 forced electric dipole transition. Similar narrow-band high-color-purity red luminescence can also be obtained by exciting with other wavelengths in the near-ultraviolet region. 5+ / Eu 3+ As the doping concentration increases, the luminescence intensity begins to increase. 0.56 Nb 0.22 Eu 0.22 TiO4 has the strongest emission strength. 0.60 Nb 0.20 Eu 0.20 TiO4, Zr in Example 9 0.80 Nb 0.10 Eu 0.10 TiO4, Zr in Example 10 0.80 Nb0.10 Eu 0.10 TiO4 and Zr in Example 11 0.80 Nb 0.10 Eu 0.10 TiO4 and Zr in Example 1 0.80 Nb 0.10 Eu 0.10 The emission spectrum distribution of TiO4 is similar to the result in Example 1, and no further illustration is provided here.

[0095] Figure 6 In order to utilize Zr in Example 1 of the present invention 0.56 Nb 0.22 Eu 0.22 TiO4, blue phosphor Sr5(PO4)3Cl:Eu 2+ and green phosphor (Ba,Sr)SiO4:Eu 2+ The electroluminescence spectrum of the white light emitting LED packaged with a near-ultraviolet chip (395-400nm) (working current 20mA) and the luminescence photo of the LED working in a dark environment. Figure 6 It can be seen that the electroluminescent color rendering index reaches R a ~90.4, the correlated color temperature is 5660K, the color coordinates are (0.328, 0.342), and it is a high-quality warm white light emission. 1-2x Nb x Eu x TiO4 phosphor has the potential to be used as a narrow-band red phosphor suitable for near-ultraviolet LED excitation.

[0096] Figure 7 In order to utilize Zr in Example 4 of the present invention 0.80 Nb 0.10 Eu 0.10 The XRD diffraction patterns of TiO4, the product in Comparative Example 1 and the product in Comparative Example 2, and the standard card pattern of orthorhombic ZrTiO4 (PDF#74-1504). NH4HCO3 is a precipitant commonly used in the coprecipitation method. Figure 7 It can be seen that when the product in Comparative Example 1 uses NH4HCO3 solution as the fifth solution (precipitant), some obvious peaks can be observed in the XRD diffraction peaks, especially the peaks between 26 and 28° are more obvious; when the product in Comparative Example 2 uses NH4HCO3 solution + ammonia solution as the fifth solution (precipitant), these peaks will also appear; in Example 4, Zr 0.80 Nb 0.10 Eu 0.10The XRD diffraction peaks of TiO4 are almost consistent with the orthorhombic ZrTiO4 standard card (PDF#74-1504), and no obvious impurity peaks are observed. This shows that using only ammonia water as a precipitant is more conducive to the pure phase Zr 1-2x Nb x Eu x Synthesis of TiO4 red phosphor.

[0097] Figure 8 In order to utilize Zr in Example 4 of the present invention 0.80 Nb 0.10 Eu 0.10 The emission spectra of TiO4, the product in Comparative Example 1 and the product in Comparative Example 2 have an excitation wavelength of 393 nm. Figure 8 It can be seen that in Example 4, Zr 0.80 Nb 0.10 Eu 0.10 When TiO4 is precipitated with ammonia water, the luminescence intensity of the sample is much higher than that of Zr 0.80 Nb 0.10 Eu 0.10 TiO4 and Zr in Comparative Example 2 0.80 Nb 0.10 Eu 0.10 The luminescence intensity of TiO4 shows that phase purity has a significant effect on luminescence intensity, and high phase purity phosphors show stronger luminescence.

[0098] The embodiments of the present application are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core idea of ​​the present application. At the same time, for general technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

[0099] The above are only preferred embodiments of the present application, and only specifically describe the technical principles of the present application. These descriptions are only for explaining the principles of the present application and cannot be interpreted as limiting the scope of protection of the present application in any way. Based on the explanation here, any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application, and other specific implementation methods of the present application that can be associated with the technicians in this field without creative work, should be included in the scope of protection of the present application.

Claims

1. A method for preparing a near-ultraviolet excited LED red phosphor, wherein the chemical formula of the near-ultraviolet excited LED red phosphor is Zr 1-2x Nb x Eu x TiO4; among them, 0.01≤x≤0.24, characterized in that it comprises the following steps: Adding Zr source, Ti source, Eu source and Nb source in deionized water in stoichiometric ratio to form a transparent solution; Adding ammonia water precipitant dropwise to the transparent solution until a suspension of milky white precipitate is generated; subjecting the suspension to an aging treatment; The aged suspension is subjected to solid-liquid separation, washed, and dried to obtain a precursor; The near-ultraviolet excited red phosphor for LED is obtained by high-temperature treatment of the precursor.

2. The method for preparing the red phosphor for near-ultraviolet excited LED according to claim 1, characterized in that: In the step of sequentially adding a Zr source, a Ti source, a Eu source and a Nb source into deionized water to form a transparent solution, the Zr source is at least one or more of Zr(SO4)2, Zr(NO3)4 or ZrOCl2 or their hydrates; the Ti source is Ti(SO4)2 or its hydrate; the Eu source is at least one or more of Eu(NO3)3, EuCl3 or their hydrates; and the Nb source is at least one or two of ammonium niobate oxalate hydrate and hydrated niobium oxalate.

3. The method for preparing the red phosphor for near-ultraviolet excited LED according to claim 1 or 2, characterized in that: Ti in transparent solution 4+ The molar concentration is 0.2~1.0mol / L.

4. The method for preparing the red phosphor for near-ultraviolet excited LED according to claim 1 or 2, characterized in that: In the step of titrating an ammonia precipitant into the solution until a suspension of a milky white precipitate is generated, the molar ratio of NH3 to the red phosphor for LED in the ammonia precipitant is 2.1 to 8.

1.

5. The method for preparing the red phosphor for near-ultraviolet excited LED according to claim 4, characterized in that: In the step of adding ammonia water precipitant to the transparent solution until a suspension of milky white precipitate is generated, the titration rate is 1 to 8 mL / min.

6. The method for preparing the red phosphor for near-ultraviolet excited LED according to claim 1, characterized in that: In the step of aging the suspension, the aging time is 8 to 12 hours.

7. The method for preparing the red phosphor for near-ultraviolet excited LED according to claim 1, characterized in that: In the step of obtaining the near-ultraviolet excited LED red phosphor after high-temperature treatment of the precursor, the high-temperature treatment is high-temperature calcination, the calcination temperature is 1200-1400° C., and the calcination time is 4-6 hours.

8. A red phosphor for near-ultraviolet excited LED, characterized in that: The near-ultraviolet excited LED red phosphor as claimed in claim 1 is prepared by the preparation method of the red phosphor.

9. Use of the near-ultraviolet excited LED red phosphor as claimed in claim 10 in a light emitting device.

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