Yellow fluorescent powder, scintillator preparation method and white light LED device

Abstract

The invention relates to the technical field of luminescent materials, in particular to yellow fluorescent powder, a scintillator preparation method and a white light LED device, and the structural formula of the yellow fluorescent powder is Ma (A) bCucId.Xe.fH2O, wherein M comprises one or more of Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba and Zn, A is C10H20O5, X comprises one or more of CH3OH, H3PO2, C3H7NO, C3H8O, C3H6O and CH3CN, a, b, c, d, e and f are molar coefficients, a is greater than or equal to 1 and less than or equal to 3, b is greater than or equal to 1 and less than or equal to 2, c is greater than or equal to 1 and less than or equal to 6, d is greater than or equal to 2 and less than or equal to 8, e is greater than or equal to 0 and less than or equal to 3, and f is greater than or equal to 1 and less than or equal to 6. The yellow fluorescent powder can emit white light without adding other fluorescent powder, is rich in raw material source, low in production cost and high in commercial use value, and can be applied to the fields of illumination, X-ray flat panel detectors, CT detectors and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of luminescent materials, and in particular to a yellow phosphor, a scintillator preparation method and a white light LED device. Background Art

[0002] White LEDs can be obtained by coating a blue LED chip with a highly efficient phosphor that can be effectively excited by blue light and emits yellow light. X-ray scintillators are a type of material that can convert high-energy X-rays into low-energy visible light (ultraviolet, visible or infrared).

[0003] Currently, significant progress has been made in the research of white LED light sources, with significant improvements in luminous efficiency and color purity. Research on similar X-ray scintillators has also made considerable progress, but most commercial phosphors currently rely heavily on rare earth elements. Furthermore, due to the hazardous nature of X-ray scintillators and the urgent need for their applications in medical and security inspections, the development of high-performance scintillators remains a pressing need. Currently, the commercial inorganic scintillator CsI:Tl has a spatial resolution of 10 lp / mm. While it offers a high light yield (54,000 photons / MeV), its low spatial resolution and inherent toxicity limit its application in X-ray imaging. The development of scintillator materials with lower detection limits, non-toxicity, or low toxicity, and higher resolution and light yield remains urgent. Developing materials that combine both illumination and scintillation properties offers broad application potential, but few researchers are currently developing these dual-functional materials. Furthermore, traditional scintillators and phosphors present several challenges, such as the stringent preparation conditions, high toxicity, hygroscopicity, and fragility. Summary of the Invention

[0004] The purpose of the present invention is to provide a yellow phosphor, a scintillator preparation method and a white light LED device, aiming to solve the problems of commercial phosphors being overly dependent on rare earth elements, requiring strict preparation conditions, being highly toxic, hygroscopic and fragile, and not being able to have both white light and X-ray scintillation functions.

[0005] To achieve the above objectives, in a first aspect, the present invention provides a yellow phosphor having a structural formula of M a (A) b Cu c I d ·X e fH2O; wherein M includes one or more of Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba and Zn, and A is C 10 H 20O5, X includes one or more of CH3OH, H3PO2, C3H7NO, C3H8O, C3H6O and CH3CN, a, b, c, d, e and f are molar coefficients, and range from 1≤a≤3, 1≤b≤2, 1≤c≤6, 2≤d≤8, 0≤e≤3, 1≤f≤6.

[0006] In a second aspect, the present invention further provides a method for preparing a blue light-excited yellow phosphor, which is used to prepare the blue light-excited yellow phosphor as described in the first aspect, comprising the following steps:

[0007] Obtain raw materials in proportion based on the phosphor structure formula, dissolve the raw materials into a solvent, and stir to obtain a suspension or a transparent solution;

[0008] Filtering the suspension through a filtering device to obtain a crude powder particle product;

[0009] placing the transparent solution in a fume hood and evaporating it at room temperature to obtain pure composite material crystals;

[0010] The crude powder particles and the composite material crystals are washed with a detergent, dried, crushed, and sieved to obtain yellow phosphor.

[0011] The raw materials include NaI, KI, RbI, CsI, BaI2, CaI2, SrI2, MgI2, ZnI2, CuI and H3PO2.

[0012] Wherein, the solvent is N,N-dimethylformamide or acetonitrile, and the detergent includes acetone, methanol, ethanol or acetonitrile.

[0013] In a third aspect, the present invention further provides a method for preparing a yellow phosphor scintillator, which is applied to the method for preparing the blue light-excited yellow phosphor described in the second aspect, comprising the following steps:

[0014] The transparent solution is placed in a larger open flat-bottomed container, and the pre-cut substrate material is placed in the container to completely soak it;

[0015] The soaked base material is taken out, suspended on a support, and placed flat to wait for the solvent to evaporate. The phosphor is then evenly precipitated on the base material and adhered to the surface;

[0016] After the base material is completely dried, a suitable transparent tape is used to film-encapsulate the base material scintillator to isolate it from air.

[0017] In a fourth aspect, the present invention also provides a white light LED device, which is applied to the yellow phosphor excited by blue light as described in the first aspect above, including a blue light-emitting chip and a yellow phosphor. The yellow phosphor can be placed directly on the blue light-emitting chip, and can also be mixed with UV glue or PDMS colloid and then encapsulated on the blue light-emitting chip.

[0018] The yellow phosphor of the present invention has the structural formula M a (A) b Cu c I d ·X e fH2O; wherein M includes one or more of Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba and Zn, and A is C 10 H 20 O5, X includes one or more of CH3OH, H3PO2, C3H7NO, C3H8O, C3H6O and CH3CN, a, b, c, d, e and f are molar coefficients in the range of 1≤a≤3, 1≤b≤2, 1≤c≤6, 2≤d≤8, 0≤e≤3, and 1≤f≤6. By replacing or adjusting the ratio of the elements, a blue-light-excited yellow phosphor for white LEDs with a wide excitation range (250-500nm) and a wide emission range (450-800nm) can be obtained. The yellow phosphor can emit white light without the addition of other phosphors. The raw materials of the yellow phosphor are abundant, the production cost is low, and the commercial value is high. The yellow phosphor can be applied to fields such as lighting, X-ray flat panel detectors and CT detectors. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 This is the XRD pattern of Ca(15-crown-5)2(C3H7NO)2Cu4I6·H2O phosphor.

[0021] Figure 2 This is the emission spectrum of Ca(15-crown-5)2(C3H7NO)2Cu4I6·H2O excited at 450nm and the excitation spectrum monitored at 540nm.

[0022] Figure 3It is the fluorescent pink coordinates of Ca(15-crown-5)2(C3H7NO)2Cu4I6·H2O (x=0.42, y=0.54).

[0023] Figure 4 This is the emission spectrum of a white light LED device based on Ca(15-crown-5)2(C3H7NO)2Cu4I6·H2O phosphor.

[0024] Figure 5 It is an X-ray scintillation luminescence spectrum based on the Ca(15-crown-5)2(C3H7NO)2Cu4I6·H2O composite material.

[0025] Figure 6 This is the minimum detection limit diagram of X-ray dose detection based on Ca(15-crown-5)2(C3H7NO)2Cu4I6·H2O composite material.

[0026] Figure 7 This is a single crystal image of a scintillator based on a Ca(15-crown-5)2(C3H7NO)2Cu4I6·H2O composite material.

[0027] Figure 8 This is a paper-based scintillator film based on Ca(15-crown-5)2(C3H7NO)2Cu4I6·H2O composite material.

[0028] Figure 9 It is a flexible X-ray scintillator film based on Ca(15-crown-5)2(C3H7NO)2Cu4I6·H2O composite material paper.

[0029] Figure 10 This is an imaging diagram of a flexible X-ray scintillator film based on Ca(15-crown-5)2(C3H7NO)2Cu4I6·H2O composite material paper.

[0030] Figure 11 The present invention provides a flow chart of a method for preparing yellow phosphor.

[0031] Figure 12 The present invention provides a yellow phosphor, a scintillator preparation method and a white light LED device. DETAILED DESCRIPTION

[0032] The following describes embodiments of the present invention in detail, examples of which 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 invention, and are not to be construed as limiting the present invention.

[0033] See also Figures 1 to 10 In the first aspect, the present invention provides a yellow phosphor having a structural formula of M a (A) b Cu c I d ·X e fH2O; wherein M includes one or more of Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba and Zn, and A is C 10 H 20 O5, X includes one or more of CH3OH, H3PO2, C3H7NO, C3H8O, C3H6O and CH3CN, a, b, c, d, e and f are molar coefficients, and range from 1≤a≤3, 1≤b≤2, 1≤c≤6, 2≤d≤8, 0≤e≤3, 1≤f≤6.

[0034] In the embodiment of the present invention, the yellow phosphor structural formula is M a (A) b Cu c I d ·X e fH2O; wherein M includes one or more of Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba and Zn, and A is C 10 H 20 O5, X includes one or more of CH3OH, H3PO2, C3H7NO, C3H8O, C3H6O and CH3CN, a, b, c, d, e and f are molar coefficients in the range of 1≤a≤3, 1≤b≤2, 1≤c≤6, 2≤d≤8, 0≤e≤3, and 1≤f≤6. By replacing or adjusting the ratio of the elements, a blue-light-excited yellow phosphor for white LEDs with a wide excitation range (250-500nm) and a wide emission range (450-800nm) can be obtained. The yellow phosphor can emit white light without the addition of other phosphors. The raw materials of the yellow phosphor are abundant, the production cost is low, and the commercial value is high. The yellow phosphor can be applied to fields such as lighting, X-ray flat panel detectors and CT detectors.

[0035] See also Figure 11 In a second aspect, the present invention further provides a method for preparing a blue light-excited yellow phosphor, which is used to prepare the blue light-excited yellow phosphor as described in the first aspect, comprising the following steps:

[0036] S1 obtains raw materials in proportion based on the phosphor structure formula, dissolves the raw materials into a solvent, and stirs to obtain a suspension or a transparent solution;

[0037] In the embodiment of the present invention, according to the chemical formula M a (A) b Cuc I d ·X e ·fH2O The raw materials of each element are weighed in proportion, and then directly dissolved into a solvent N,N-dimethylformamide or acetonitrile, and stirred or ultrasonically reacted to obtain a suspension or a transparent solution. The raw materials include NaI, KI, RbI, CsI, BaI2, CaI2, SrI2, MgI2, ZnI2, CuI and H3PO2.

[0038] S2: filtering the suspension through a filtering device to obtain a crude powder particle product;

[0039] S3: placing the transparent solution in a fume hood and evaporating it at room temperature to obtain pure composite material crystals;

[0040] S4: washing the crude powder particles and the composite material crystals with a detergent, drying, crushing, and sieving to obtain yellow phosphor.

[0041] In an embodiment of the present invention, the crude powder particles and the composite material crystals are washed with acetone, methanol, ethanol or acetonitrile, dried, crushed and sieved to obtain the final product.

[0042] In the third aspect, the present invention also provides a white light LED device, which is applied to the yellow phosphor excited by blue light as described in the first aspect above, including a blue light-emitting chip and a yellow phosphor. The yellow phosphor can be placed directly on the blue light-emitting chip, and can also be mixed with UV glue or PDMS colloid and then encapsulated on the blue light-emitting chip.

[0043] See also Figure 12 In a fourth aspect, the present invention further provides a method for preparing a yellow phosphor scintillator, which is used to prepare the blue light-excited yellow phosphor preparation method as described in the second aspect above, comprising the following steps:

[0044] S01: placing the transparent solution in a larger open flat-bottomed container, and placing the pre-cut substrate material in the container to completely soak it;

[0045] In an embodiment of the present invention, the transparent solution is placed in a larger open flat-bottomed container, such as a 20*20 cm culture dish, and a pre-cut substrate material (such as weighing paper, filter paper, etc.) is placed in the container to completely soak it and allowed to stand for 5-10 minutes.

[0046] S02: taking out the soaked base material, suspending it with a support, and laying it flat to wait for the solvent to evaporate. The phosphor then precipitates evenly on the base material and adheres to the surface;

[0047] S03 After the base material is completely dried, a suitable transparent tape is used to film-encapsulate the base material scintillator to isolate it from air.

[0048] The present invention adopts the simplest and most direct solution synthesis method, which is easy to operate, does not involve complex processes and high-energy equipment, has strong repeatability, can be quickly mass-produced, and avoids the shortcomings of traditional phosphor preparation such as high temperature and high pressure. By replacing or adjusting the element ratio, a yellow phosphor for white LED excited by blue light with a wide excitation range (250-500nm) and a wide emission range (450-800nm) can be obtained, which does not need to add other phosphors to emit white light. A variety of technical solutions can be used to prepare X-ray scintillators, and flexible and non-flexible scintillators can be prepared at the same time. A flexible scintillator film can be quickly obtained according to the size of the paper base by a primer coating method. The present invention also provides several methods for preparing flexible scintillator films, which can be bent and folded at will, solving the fundamental problems of existing rigid scintillator screens; the present invention has abundant raw material sources, low production costs, high commercial value, and can be applied to lighting fields, X-ray flat panel detectors, CT detectors and other fields.

[0049] For a better understanding of the present technical solution, the following examples are provided for further explanation:

[0050] In the first embodiment, the present invention provides a blue light excited yellow phosphor, the chemical formula of which is Ca(15-crown-5)2(C3H7NO)2Cu4I6·H2O.

[0051] The XRD diffraction pattern shows that it has a monoclinic P21 / c structure.

[0052] The present invention also provides a method for preparing blue light excited yellow phosphor, comprising the following steps:

[0053] 1. Weigh the corresponding element compound raw materials according to the chemical formula, calcium iodide, cuprous iodide, 15-crown ether-5, and H3PO2, and place them in a reaction vessel (beaker or reactor, etc.);

[0054] 2. Adding a reaction solvent, N,N-dimethylformamide, methanol or acetonitrile, to the reaction vessel containing the raw materials and performing stirring or ultrasonic reaction to obtain a mixed solution after the reaction is completed;

[0055] 3. Filter the mixed solution to obtain a yellow powder solid;

[0056] Fourth, the powdered solid product is washed, dried, ground and sieved to obtain the blue light excited yellow phosphor.

[0057] The present invention further provides a method for preparing a paper-based X-ray scintillator film, comprising the following steps:

[0058] 1. Weigh the corresponding element compound raw materials and solvent according to the chemical formula, including calcium iodide, cuprous iodide, 15-crown ether-5, and H3PO2, and place them in a reaction vessel (beaker or reactor, etc.). Add solvent N,N-dimethylformamide or acetonitrile to dissolve them and make the solution clear.

[0059] 2. Place the clarified solution in a larger open flat-bottomed container, such as a 20*20 cm Petri dish;

[0060] 3. Place the filter paper in the Petri dish containing the solution, allow the "paper" to be completely soaked, and let it stand for 5-10 minutes;

[0061] 4. Then take out the soaked paper, use a support to suspend the paper, lay the paper flat and wait for the solvent to evaporate, and the composite material will then be evenly precipitated and attached to the inner and outer surfaces of the paper;

[0062] 5. After the paper is completely dry, use suitable transparent tape to seal the paper scintillator to isolate it from the air.

[0063] The present invention further provides a method for preparing a flexible X-ray scintillator film, comprising the following steps:

[0064] 1. Under normal temperature and pressure, the composite material powder is ground and sieved, and then added to DMF with PVDF, heated and stirred at high speed to mix evenly, to prepare a scintillator glue pre-dispersion liquid;

[0065] 2. Evenly drip the obtained scintillator glue pre-dispersion liquid into the plastic mold prepared in advance. When the ambient temperature is less than 20°C and the humidity is higher than 70%, place it in a vacuum drying oven to dry and solidify. When the ambient temperature is higher than 20°C and the humidity is lower than 70%, place it in an environment to dry and solidify.

[0066] The present invention further provides a white light LED device, comprising a blue light-emitting chip and yellow phosphor arranged on the light-emitting chip; the yellow phosphor can be placed directly on the blue light-emitting chip, or it can be mixed with UV glue or PDMS and then encapsulated on the blue light-emitting chip. After encapsulation, a white light LED device that is excited to emit light and is not easily damaged can be obtained.

[0067] The blue light emitting chip may be an InGnN semiconductor LED chip with a light emitting wavelength of 460 nm.

[0068] The amount of the yellow phosphor used is not particularly limited and can be adjusted according to actual needs. The blue light-emitting chip is a GaN semiconductor chip, such as an InGnN semiconductor LED chip, with a peak emission wavelength of 460nm. The yellow phosphor has advantages such as a wide excitation range in the blue light region, high color purity, and good thermal and chemical stability. It is suitable for blue light chips and blue light-excited LED devices. The white light LED device provided by the present invention overcomes the shortcomings of traditional commercial white light LED devices due to the lack of directly assembled yellow phosphor.

[0069] The above disclosure is merely a preferred embodiment of a yellow phosphor, a scintillator preparation method, and a white light LED device of the present invention. It is certainly not intended to limit the scope of the present invention. A person skilled in the art will understand that implementing all or part of the processes of the above embodiments and making equivalent changes in accordance with the claims of the present invention still fall within the scope of the invention.

Claims

1. A blue light excited yellow phosphor, characterized in that; The yellow phosphor structural formula is M a (A) b Cu c I d ·X e fH2O; Wherein, M includes one or more of Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba and Zn, and A is C 10 H 20 O5, X includes one or more of CH3OH, H3PO2, C3H7NO, C3H8O, C3H6O and CH3CN, a, b, c, d, e and f are molar coefficients, and range from 1≤a≤3, 1≤b≤2, 1≤c≤6, 2≤d≤8, 0≤e≤3, 1≤f≤6.

2. A method for preparing a blue light excited yellow phosphor, for preparing the blue light excited yellow phosphor as claimed in claim 1, characterized in that: The following steps are involved: Obtain raw materials in proportion based on the phosphor structure formula, dissolve the raw materials into a solvent, and stir to obtain a suspension or a transparent solution; Filtering the suspension through a filtering device to obtain a crude powder particle product; placing the transparent solution in a fume hood and evaporating it at room temperature to obtain pure composite material crystals; The crude powder particles and the composite material crystals are washed with a detergent, dried, crushed, and sieved to obtain yellow phosphor.

3. The method for preparing a blue light excited yellow phosphor according to claim 2, wherein ； The raw materials include NaI, KI, RbI, CsI, BaI2, CaI2, SrI2, MgI2, ZnI2, CuI and H3PO2.

4. The method for preparing a blue light excited yellow phosphor according to claim 2, wherein ； The solvent is N,N-dimethylformamide or acetonitrile, and the detergent includes acetone, methanol, ethanol or acetonitrile.

5. A white light LED device, applied to the blue light excited yellow phosphor according to claim 1, characterized in that; It includes a blue light-emitting chip and yellow phosphor. The yellow phosphor can be directly placed on the blue light-emitting chip, or it can be mixed with UV glue or PDMS colloid and then packaged on the blue light-emitting chip.

6. A method for preparing a yellow phosphor scintillator, which is used to prepare the blue light excited yellow phosphor preparation method according to claim 2, characterized in that: The following steps are involved: The transparent solution is placed in a larger open flat-bottomed container, and the pre-cut substrate material is placed in the container to completely soak it; The soaked base material is taken out, suspended on a support, and placed flat to wait for the solvent to evaporate. The phosphor is then evenly precipitated on the base material and adhered to the surface; After the base material is completely dried, a suitable transparent tape is used to film-encapsulate the base material scintillator to isolate it from air.

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