A lead-free bimetallic halide single crystal luminescent material with variable excitation, preparation method and application thereof

Abstract

The present invention belongs to the technical field of luminescent materials, and specifically relates to a variable excitation lead-free bimetallic halide single crystal luminescent material and a preparation method and application thereof. The chemical formula of the single crystal luminescent material is A4BB'X9, including [B'X5] 2‑ and [BX4] 2‑ Two luminous centers, [BX4] 2‑ is a tetrahedral configuration, [B'X5] 2‑ It is a pentahedral configuration; wherein A is an organic cation group; B is a divalent metal, B' is a trivalent metal; and X is one or more halogen anions. The variable excitation lead-free bimetallic halide single crystal luminescent material provided by the present invention has variable multiple excitation, excellent luminescent performance, high fluorescence quantum yield, and high stability, and has great promotion value in the fields of scintillation imaging and white light LED for lighting.

Description

Technical Field

[0001] The invention belongs to the technical field of luminescent materials, and in particular relates to a variable-excitation lead-free bimetallic halide single crystal luminescent material and a preparation method and application thereof. Background Art

[0002] In recent years, halide perovskite materials have been widely used in solar cells, LEDs, lasers, etc. due to their excellent optical properties. However, with the further deepening of research, many problems that restrict their development and application have also come one after another. First, the application of halide perovskite materials is hindered by the toxicity and poor stability of lead elements; secondly, the efficient luminescence of perovskites is mainly concentrated in quantum dot luminescence, which has the advantages of high fluorescence quantum yield, narrow fluorescence peak, and adjustable fluorescence color. However, the fluorescence of perovskite bulk materials is often extremely weak, and the fluorescence color is single, which seriously hinders the application of such materials in LEDs and scintillators. Therefore, it is of far-reaching significance to optimize the process and design and prepare lead-free bimetallic halide single crystal materials with efficient luminescence and variable excitation. Summary of the invention

[0003] In view of the problems that the existing halide perovskite materials exhibit weak bulk material fluorescence and a single fluorescence color, the present invention proposes a lead-free bimetallic halide single crystal luminescent material with variable excitation, a preparation method and application thereof, and a bimetallic mixing method is used to concentrate multiple luminescent sites in the same material, thereby realizing the preparation of lead-free bimetallic halide single crystal luminescent material with variable excitation; a single crystal luminescent material with a chemical formula of A4BB'X9 is prepared for the first time, and the single crystal luminescent material has multiple luminescent centers, variable laser and high fluorescence yield.

[0004] The technical solution of the present invention is:

[0005] A lead-free bimetallic halide single crystal luminescent material with variable excitation, the chemical formula of the single crystal luminescent material is A4BB'X9, including [B'X5] 2- and [BX4] 2- Two luminescent centers, among which [BX4] 2- is a tetrahedral configuration, [B'X5] 2- It is a pentahedral configuration.

[0006] In the above chemical formula, A is an organic cationic group, preferably, A is a cationic group of one or more compounds selected from tetramethylamine, tetraethylamine, tetrapropylamine, tetrabutylamine, and tetraphenylphosphine;

[0007] B is a divalent metal, preferably, B is one or more of Mn, Zn, and Cu;

[0008] B' is a trivalent metal, preferably, B' is one or more of Sb, Bi, In and trivalent rare earth elements, wherein the trivalent rare earth metals include La, Ce, Sm, etc.;

[0009] X is one or more halogen anions, preferably, X is Cl - ,Br - , I - One or more of .

[0010] Furthermore, the single crystal material provided by the present invention has a specific structure, the selected metal valence state is B divalent, B' trivalent, and is easy to form a zero-dimensional perovskite structure, thereby forming [BX4] 2- Tetrahedral configuration and [B'X5] 2- Pentahedral configuration, the structure of the single crystal is [B'X5] 2- Pentahedron and [BX4] 2- The tetrahedra are arranged at intervals, and the organic A cations are dispersed in the gaps.

[0011] Furthermore, the scale of the single crystal luminescent material is 1×10 -3 mm~40mm; the single crystal luminescent material has multiple luminescent centers, which are variable excitation, and its luminescence is regulated according to the element content and type of B and B', the excitation wavelength is 250nm~500nm, and the emission wavelength is 480nm~750nm.

[0012] The present invention also provides a method for preparing a lead-free bimetallic halide single crystal luminescent material with variable excitation, comprising the following steps:

[0013] Weigh appropriate amounts of BX2, B'X3 and AX according to a molar ratio of 1:1:4, mix them and dissolve them in an appropriate amount of DMF solution or a mixed solution of DMF and acetonitrile; heat and dissolve them at a temperature of 60 to 120°C; after they are completely dissolved, cool them naturally or slowly at a rate of 0.5 to 1°C / h to room temperature to obtain the target material; wash the target material to obtain a single crystal luminescent material.

[0014] Further, BX2 includes MnCl2, ZnCl2, CuCl2, MnBr2, ZnBr2, CuBr2, MnI2, ZnI2, and CuI2; in the preparation step, the weighed BX2 is any one of MnCl2 or ZnCl2 or CuCl2 or MnBr2 or ZnBr2 or CuBr2 or MnI2 or ZnI2 or CuI2, and can also be a combination of any two of MnCl2, ZnCl2, CuCl2, MnBr2, ZnBr2, CuBr2, MnI2, ZnI2, and CuI2, or a mixture of any three or more thereof;

[0015] B'X3 includes SbCl3, BiCl3, InCl3, LaCl3, CeCl3, SbBr3, BiBr3, InBr3, SbI3, BiI3, InI3; in the specific preparation process, the selected B'X3 is any one of SbCl3 or BiCl3 or InCl3 or LaCl3 or CeCl3 or SbBr3 or BiBr3 or InBr3 or SbI3 or BiI3 or InI3, and can also be a combination of any two of SbCl3, BiCl3, InCl3, LaCl3, CeCl3, SbBr3, BiBr3, InBr3, SbI3, BiI3, InI3, or a mixture of any three or more;

[0016] AX includes tetramethylammonium chloride, tetraethylammonium chloride, tetrapropylammonium chloride, tetrabutylammonium chloride, tetraphenylphosphonium chloride, tetramethylammonium bromide, tetramethylammonium iodide, tetraethylammonium bromide, tetraethylammonium iodide, tetrapropylammonium bromide, tetrapropylammonium iodide, tetrabutylammonium bromide, tetrabutylammonium iodide, tetraphenylphosphonium bromide, and tetraphenylphosphonium iodide; specifically, AX selects any one of tetramethylammonium chloride, tetraethylammonium chloride, tetrapropylammonium chloride, tetrabutylammonium chloride, tetraphenylphosphonium chloride, tetramethylammonium bromide, tetramethylammonium iodide, tetraethylammonium bromide, tetraethylammonium iodide, tetrapropylammonium bromide, tetrapropylammonium iodide, tetrabutylammonium bromide, tetrabutylammonium iodide, tetraphenylphosphonium bromide, and tetraphenylphosphonium iodide, or a combination of any two or more thereof.

[0017] The invention also protects the application of the single crystal luminescent material in LED.

[0018] Furthermore, there are two methods for its application in LEDs. One is to obtain two single crystal materials by adjusting the element types and contents of B and B', which emit bright orange light and blue-green light respectively, and mix the two luminescent materials in a ratio of 1:1 to 10 to tune and obtain white light;

[0019] The second is to grind the single crystal material into uniform fine powder, mix it with matching commercial phosphors according to the principle of three primary colors, and obtain efficient white light LEDs under the excitation of blue LED chips.

[0020] The present invention also protects the use of single crystal luminescent materials in X-ray scintillator imaging.

[0021] Furthermore, the single crystal luminescent material is ground into uniform fine powder, mixed with sucrose octaacetate melt in a mass ratio of 3:7, then melted at 140-180°C, and evenly coated on a glass sheet to obtain a scintillator screen with uniform thickness, which is then applied to X-ray imaging.

[0022] The above melting temperatures include 140°C, 150°C, 155°C, 160°C, 165°C, 170°C, 180°C and the like.

[0023] Beneficial effects of the present invention:

[0024] The variable excitation lead-free bimetallic halide single crystal luminescent material provided by the present invention has variable multiple excitation, excellent luminescent performance, high fluorescence quantum yield, and high stability, and has great promotion value in the fields of scintillation imaging and white light LED for lighting. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is an appearance morphology diagram of the TTA4MnSbCl9 single crystal prepared in Example 1 of the present invention;

[0026] Figure 2 This is a structural photograph of the TTA4MnSbCl9 single crystal prepared in Example 1 of the present invention;

[0027] Figure 3 This is a fluorescence photograph of the TTA4MnSbCl9 single crystal prepared in Example 1 of the present invention under ultraviolet light excitation;

[0028] Figure 4 The excitation spectrum and emission spectrum of TTA4MnSbCl9 prepared in Example 1 of the present invention are shown in the figure. In the figure, (a) is the excitation spectrum at an emission wavelength of 600nm, (b) is the emission spectrum at an excitation wavelength of 397nm, (c) is the excitation spectrum at an emission wavelength of 521nm, and (d) is the emission spectrum at an excitation wavelength of 450nm.

[0029] Figure 5 The application of TTA4MnSbCl9 prepared in Example 1 of the present invention in white light LED;

[0030] Figure 6 Application of TTA4MnSbCl9 prepared in Example 1 of the present invention in X-ray scintillator imaging;

[0031] Figure 7 This is a photograph of the appearance of the TTA4MnBiCl9 single crystal prepared in Example 2 of the present invention. DETAILED DESCRIPTION

[0032] In order to further understand the present invention, the present invention will be further described below in conjunction with the accompanying drawings and embodiments, and the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] The present invention provides a variable excitation lead-free bimetallic halide single crystal luminescent material, the single crystal luminescent material comprises [B'X5] 2- and [BX4] 2- Two luminous centers, [BX4] 2- is a tetrahedral configuration, [B'X5] 2- It is a pentahedral configuration; the structure of the single crystal is [B'X5] 2- Pentahedron and [BX4] 2- The tetrahedrons are arranged at intervals, and the A cations are dispersed in the gaps.

[0034] The method for preparing the single crystal luminescent material comprises the following steps:

[0035] Weigh appropriate amounts of salts BX2, B'X3 and AX according to a molar ratio of 1:1:4, and mix them; add an appropriate amount of DMF solution or a mixed solution of DMF and acetonitrile to the mixed salt, and heat to dissolve at any temperature in the temperature range of 60 to 120°C; after the mixed salt is completely dissolved, cool naturally or slowly at a rate of 0.5 to 1°C / h to obtain the target product, wash the product, and obtain a lead-free bimetallic halide single crystal luminescent material with variable excitation.

[0036] The application of the single crystal luminescent material includes the following two methods:

[0037] (1) When the B element is determined, by adjusting the element type and content of B', two single crystal materials are obtained, which emit bright orange light and blue-green light respectively. The two luminescent materials are mixed in a ratio of 1:1 to 10 and tuned to obtain white light LEDs.

[0038] Another method is to grind the single crystal material into uniform fine powder, mix it with matching commercial phosphors according to the principle of three primary colors, and obtain efficient white light LEDs under the excitation of blue LED chips.

[0039] (2) The single crystal material is ground into uniform fine powder, mixed with sucrose octaacetate melt in a mass ratio of 3:7, melted at any temperature in the range of 140 to 180°C, and evenly coated on a glass sheet. The powder is further extruded with the same glass sheet interlayer to form a scintillator screen with uniform thickness, which is then used for X-ray imaging.

[0040] Example 1

[0041] Preparation of TTA4MnSbCl9 single crystal, the preparation method comprises the following steps:

[0042] Weigh 1mmol MnCl2, 1mmol SbCl3 and 4mmol tetraethylammonium chloride respectively, mix the weighed salts, add an appropriate amount of DMF solution, heat to dissolve at 100℃, and slowly cool at a rate of 1℃ / h to room temperature after it is completely dissolved, wash, and obtain large-sized TTA4MnSbCl9 single crystals. Figure 1 As shown in FIG. 1 , a photograph of the appearance of the single crystal luminescent material is shown. Figure 2 Shown is the corresponding single crystal structure.

[0043] The TTA4MnSbCl9 single crystal in this example belongs to the Tetragonal system and the P4 / n space group. The structure shows [SbCl5] 2- Pentahedron and [MnCl4] 2- Tetrahedrons are arranged at intervals, and organic A cations are dispersed in the gaps. Figure 3 As shown, under 365nm excitation, the single crystal exhibits bright orange light; the corresponding excitation and emission spectra are shown in Figure 4 As shown in the figure, it can be seen that the single crystal luminescent material has a variable excitation and emission spectrum. Under different excitation conditions, a fluorescence quantum yield higher than 90% can be obtained.

[0044] Application of TTA4MnSbCl9 single crystal in LED:

[0045] The TTA4MnSbCl9 single crystal material is ground into uniform fine powder, mixed with matching commercial phosphors according to the principle of three primary colors, and an efficient warm white LED is obtained under the excitation of a blue LED chip, such as Figure 5 shown.

[0046] Application of TTA4MnSbCl9 single crystal in X-ray scintillator imaging:

[0047] The TTA4MnSbCl9 single crystal material is ground into uniform fine powder, mixed with sucrose octaacetate melt in a mass ratio of 3:7, then melted at 160°C, and evenly coated on a glass sheet to obtain a scintillator screen with uniform thickness, which is then used for X-ray scintillator imaging to obtain clear imaging photos, such as Figure 6 shown.

[0048] Example 2

[0049] Preparation of TTA4MnBiCl9 single crystal, the preparation method comprises the following steps:

[0050] 1mmol MnCl2, 1mmol BiCl3 and 4mmol tetraethylammonium chloride were mixed, and an appropriate amount of DMF / acetonitrile mixed solution was added. After dissolving at 100℃, the temperature was slowly lowered at a rate of 1℃ / h to obtain a large-sized TTA4MnBiCl9 single crystal, such as Figure 7 The figure shows the appearance of the single crystal luminescent material; its single crystal structure type is the same as that of Example 1.

[0051] Application of TTA4MnBiCl9 single crystal in LED:

[0052] The TTA4MnBiCl9 single crystal material is ground into uniform fine powder and mixed with matching commercial phosphors according to the principle of three primary colors to obtain efficient warm white light LEDs under the excitation of blue light LED chips.

[0053] Application of TTA4MnBiCl9 single crystal in X-ray scintillator imaging:

[0054] The TTA4MnBiCl9 single crystal material is ground into uniform fine powder, mixed with sucrose octaacetate melt in a mass ratio of 3:7, then melted at 160°C, and evenly coated on a glass sheet to obtain a scintillator screen with uniform thickness, which is then used for X-ray scintillator imaging to obtain clear imaging photos, such as Figure 6 shown.

[0055] Example 3

[0056] Preparation of TTA4ZnInCl9 single crystal, the preparation method comprises the following steps:

[0057] Weigh 1mmol ZnCl2, 1mmol InCl3 and 4mmol tetraethylammonium chloride respectively, mix them, add an appropriate amount of DMF solution, heat and dissolve them at 60°C, and after they are completely dissolved, naturally cool them at a rate of 0.5°C / h. After they cool to room temperature, wash them to obtain large-sized TTA4ZnInCl9 single crystals.

[0058] The application in this embodiment is the same as that in embodiment 1.

[0059] Example 4

[0060] TTA4Mn 0.5 Zn 0.5 Preparation of BiCl9 single crystal, the preparation method comprises the following steps:

[0061] Weigh 1mmol MnCl2, 1mmol ZnCl2, 2mmol SbCl3 and 8mmol tetraethylammonium chloride respectively, mix them, add an appropriate amount of DMF solution, heat and dissolve them at 90℃, and after they are completely dissolved, slowly cool them at a rate of 1℃ / h. After they are cooled to room temperature, wash them and obtain large-sized TTA4Mn 0.5 Zn 0.5 BiCl9 single crystal.

[0062] The application in this embodiment is the same as that in embodiment 1.

[0063] Example 5

[0064] TTA4MnSb 0.5 Bi 0.5 Preparation of Cl9 single crystal, the preparation method comprises the following steps:

[0065] Weigh 4mmol MnCl2, 2mmol SbCl3 and 2mmol BiCl3, and 16mmol tetraethylammonium chloride, respectively, and mix them. Add an appropriate amount of DMF / acetonitrile mixed solution, heat and dissolve them at 80℃. After they are completely dissolved, cool them naturally at a rate of 0.8℃ / h. After they are cooled to room temperature, wash them and obtain large-sized TTA4MnSb 0.5 Bi 0.5 Cl9 single crystal.

[0066] The application in this embodiment is the same as that in embodiment 1.

[0067] Example 6

[0068] Preparation of TTA4MnSbBr9 single crystal, the preparation method comprises the following steps:

[0069] Weigh 1mmol MnBr2, 1mmol SbBr3 and 4mmol tetraethylammonium bromide respectively, mix them, add an appropriate amount of DMF / acetonitrile mixed solution, heat and dissolve them at 110°C, and after they are completely dissolved, naturally cool them at a rate of 0.7°C / h. After cooling to room temperature, wash them to obtain large-sized TTA4MnSbBr9 single crystals.

[0070] The application in this embodiment is the same as that in embodiment 1.

[0071] Example 7

[0072] Preparation of TMP4MnSbCl9 single crystal, the preparation method comprises the following steps:

[0073] Weigh 1mmol MnCl2, 1mmol SbCl3 and 4mmol tetramethylammonium chloride respectively, mix them, add an appropriate amount of DMF solution, heat and dissolve them at 90°C, and after they are completely dissolved, slowly cool them at a rate of 0.9°C / h. After they cool to room temperature, wash them to obtain large-sized TMP4MnSbCl9 single crystals.

[0074] The application in this embodiment is the same as that in embodiment 1.

[0075] Example 8

[0076] Preparation of TPA4MnSbCl9 single crystal, the preparation method comprises the following steps:

[0077] Weigh 1mmol MnCl2, 1mmol SbCl3 and 4mmol tetrapropylammonium chloride respectively, mix them, add an appropriate amount of DMF solution, heat and dissolve them at 100°C, and after they are completely dissolved, cool them naturally at a rate of 1°C / h. After they drop to room temperature, wash them to obtain large-sized TPA4MnSbCl9 single crystals.

[0078] The application in this embodiment is the same as that in embodiment 1.

[0079] Example 9

[0080] Preparation of TPP4MnSbCl9 single crystal, the preparation method comprises the following steps:

[0081] Weigh 1mmol MnCl2, 1mmol SbCl3 and 4mmol tetraphenylphosphonium chloride respectively, mix them, add an appropriate amount of DMF / acetonitrile mixed solution, heat and dissolve them at 100°C, and after they are completely dissolved, cool them naturally at a rate of 0.7°C / h. After cooling to room temperature, wash them to obtain large-sized TPP4MnSbCl9 single crystals.

[0082] The application in this embodiment is the same as that in embodiment 1.

[0083] Example 10

[0084] Preparation of TPP4MnSbBr9 single crystal, the preparation method comprises the following steps:

[0085] Weigh 1mmol MnBr2, 1mmol SbBr3 and 4mmol tetraphenylphosphonium bromide respectively, mix them, add an appropriate amount of DMF / acetonitrile mixed solution, heat and dissolve them at 110°C, and after they are completely dissolved, naturally cool them at a rate of 0.7°C / h. After they cool to room temperature, wash them to obtain large-sized TPP4MnSbBr9 single crystals.

[0086] The application in this embodiment is the same as that in embodiment 1.

[0087] The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can still modify the technical solutions described in the above embodiments, or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, modification, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A variable excitation lead-free bimetallic halide single crystal luminescent material, characterized in that: The chemical formula of the single crystal luminescent material is A4BB'X9, including [B'X5] 2- and [BX4] 2- Two luminous centers, [BX4] 2- is a tetrahedral configuration, [B'X5] 2- It is a pentahedral configuration; wherein A is a cationic group of one or more of tetramethylamine, tetraethylamine, tetrapropylamine, and tetrabutylamine; B is one or more of Mn, Zn, and Cu; B' is one or more of Sb, Bi, and In; X is Cl - ,Br - , I - One or more of; The scale of the single crystal luminescent material is 1×10 -3 mm~40mm; the single crystal luminescent material has multiple luminescent centers, and its luminescence is regulated according to the element content and type of B and B', the excitation wavelength is 250nm~500nm, and the emission wavelength is 480nm~750nm; The single crystal luminescent material is used in LED or X-ray scintillator imaging.

2. The single crystal luminescent material according to claim 1, characterized in that: The structure of the single crystal is [B'X5] 2- Pentahedron and [BX4] 2- The tetrahedrons are arranged at intervals, and the A cations are dispersed in the gaps.

3. The method for preparing a single crystal luminescent material according to any one of claims 1 or 2, characterized in that: The steps include: Weigh appropriate amounts of BX2, B'X3 and AX according to a molar ratio of 1:1:4, mix them and dissolve them in an appropriate amount of DMF solution or a mixed solution of DMF and acetonitrile; heat and dissolve them at a temperature of 60 to 120°C; after they are completely dissolved, cool them naturally or slowly at a rate of 0.5 to 1°C / h to room temperature to obtain the target material; The target material is washed to obtain a single crystal luminescent material.

4. The preparation method according to claim 3, characterized in that: BX2 includes MnCl2, ZnCl2, CuCl2, MnBr2, ZnBr2, CuBr2, MnI2, ZnI2, CuI2; B'X3 includes SbCl3, BiCl3, InCl3, SbBr3, BiBr3, InBr3, SbI3, BiI3, InI3; AX includes tetramethylammonium chloride, tetraethylammonium chloride, tetrapropylammonium chloride, tetrabutylammonium chloride, tetramethylammonium bromide, tetramethylammonium iodide, tetraethylammonium bromide, tetraethylammonium iodide, tetrapropylammonium bromide, tetrapropylammonium iodide, tetrabutylammonium bromide, and tetrabutylammonium iodide.

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