A lead-free zero-dimensional organic-inorganic hybrid metal halide single crystal material, preparation method and application thereof

Abstract

The present invention relates to a lead-free zero-dimensional organic-inorganic hybrid metal halide single crystal material, a preparation method and its application, and belongs to the technical field of luminescent materials. The chemical formula of the material is (C4H 12 N2O)(C4H 11 N2O)BiCl6 or (C4H 12 N2O)(C4H 11 N2O)BiBr6;BiCl6 3‑ or BiBr6 3‑ The inorganic octahedron is octahedralized by the organic cation N-acetylethylenediamine (C4H 12 N2O) 2+ With (C4H 11 N2O) + The single crystal material is prepared by an anti-solvent method. The single crystal material has high stability and excellent pressure-induced luminescence performance.

Description

Technical Field

[0001] The present invention relates to a lead-free zero-dimensional organic-inorganic hybrid metal halide single crystal material, a preparation method and application thereof, and belongs to the technical field of luminescent materials. Background Art

[0002] Pressure-induced emission (PIE) refers to the process of manipulating the luminescence of materials through pressure, enabling materials that exhibit no luminescence at normal pressure to exhibit fluorescence from scratch. High-quality luminescence can be achieved under extreme high-pressure conditions. Low-dimensional organic-inorganic hybrid metal halides, due to their reduced electronic and structural dimensionality, exhibit strong quantum confinement, making excitons more easily trapped. Furthermore, their low-dimensional, twisted structures lead to strong electroacoustic coupling, which converts bound excitons into self-trapped states. The unique broadband emission from these self-trapped states opens the possibility of fabricating single-component white light-emitting diodes. However, under normal pressure, some structures exhibit low structural distortion, resulting in weak electroacoustic coupling and low exciton binding energy. Self-trapped excitons easily return to their bound states, making efficient self-trapped luminescence difficult to achieve. High pressure, as an important fundamental thermodynamic parameter, can effectively modulate the crystal and electronic structures of these functional materials, thereby altering their physicochemical properties and inducing new phenomena that can be exploited under extreme environmental conditions. In particular, the novel phenomenon of non-luminescent materials emitting light under high pressure, without changing their composition, has attracted widespread attention and has potential applications in pressure sensing, pressure switches, and anti-counterfeiting. Therefore, the development of new low-dimensional organic-inorganic hybrid metal halide materials with pressure-induced luminescence is of great significance.

[0003] Among low-dimensional organic-inorganic hybrid metal halides, zero-dimensional metal halides have emerged as a star material in the field of pressure-induced luminescence (PIL) in recent years. In their zero-dimensional structure, inorganic metal halide units are surrounded by large organic cations and completely isolated from each other, allowing them to have more compression space under high pressure compared to other two-dimensional or one-dimensional metal halides, allowing them to still exhibit their inherent luminescence properties under even greater pressures. However, current research on zero-dimensional metal halides with PIL properties is limited, and most use the toxic lead (Pb) as the metal element. This limited material selection and the toxicity of Pb hinder further exploration and application of zero-dimensional metal halides in the field of PIL. Therefore, developing new lead-free zero-dimensional metal halide materials with PIL properties is urgent. Summary of the Invention

[0004] In view of this, the object of the present invention is to provide a lead-free zero-dimensional organic-inorganic hybrid metal halide single crystal material, a preparation method and applications thereof.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] A lead-free zero-dimensional organic-inorganic hybrid metal halide single crystal material, the chemical formula of the material is (C4H 12 N2O)(C4H 11 N2O)BiCl6((N-AD)2BiCl6) or (C4H 12 N2O)(C4H 11 N2O)BiBr6((N-AD)2BiBr6);BiCl6 3- or BiBr6 3- The inorganic octahedron is octahedralized by the organic cation N-acetylethylenediamine (C4H 12 N2O) 2+ With (C4H 11 N2O) + Separated into independent island structures; the unit cell parameters of the single crystal material are shown in Table 1 below:

[0007] Table 1

[0008]

[0009]

[0010] A method for preparing the lead-free zero-dimensional organic-inorganic hybrid metal halide single crystal material of the present invention comprises the following steps:

[0011] N-acetylethylenediamine (C4H 10 N2O, N-Acetylethylenediamine, abbreviated as N-AD) and B-site metal oxide or B-site metal halide are added to a halogen acid solution, and an anti-solvent method is used to prepare a zero-dimensional organic-inorganic hybrid metal halide single crystal material;

[0012] Wherein, the B-site metal oxide is Bi2O3;

[0013] The B-site metal halide is BiCl3 or BiBr3;

[0014] The halogen acid is hydrochloric acid or hydrobromic acid.

[0015] Preferably, the molar ratio of the N-acetylethylenediamine to the B-site metal oxide is 1:2 to 1:3; the molar ratio of the N-acetylethylenediamine to the B-site metal halide is 1:2 to 1:3.

[0016] Preferably, the molar ratio of the B-site metal oxide to the halogen acid is 1:1 to 3:1; the molar ratio of the B-site metal halide to the halogen acid is 1:1 to 3:1.

[0017] Preferably, the anti-solvent is methanol or diethyl ether.

[0018] Preferably, the volume ratio of the halogen acid to the anti-solvent is 3:5 to 5:5.

[0019] An application of the zero-dimensional organic-inorganic hybrid metal halide single crystal material of the present invention, wherein the material is used as a pressure-induced luminescence material.

[0020] Preferably, the (C4H 12 N2O)(C4H 11 N2O)BiCl6 is used as a pressure-induced violet light emitting material, and the pressure is 2 to 30 GPa. More preferably, the pressure is 12 to 18 GPa.

[0021] Preferably, the (C4H 12 N2O)(C4H 11 N2O)BiBr6 is used as a pressure-induced blue light emitting material, and the pressure is 2 to 20 GPa. More preferably, the pressure is 7 to 12 GPa.

[0022] Beneficial effects

[0023] The material of the present invention is a lead-free zero-dimensional organic-inorganic hybrid metal halide single crystal material, wherein the single crystal material A is an organic cation of N-acetylethylenediamine, and B is a metal ion Bi 3+ , X is a halogen ion Cl - or Br - ; The single crystal material has high stability and excellent pressure-induced luminescence performance.

[0024] The present invention provides a method for preparing a lead-free zero-dimensional organic-inorganic hybrid metal halide single crystal material, which can be prepared by an anti-solvent method. Compared with the high-temperature volatilization method and the programmed cooling method, the anti-solvent method described in the present invention has simpler experimental conditions and a simpler experimental method. The obtained rod-shaped crystals are transparent and are near-perfect single crystal materials with fewer defects.

[0025] This invention provides an application for a lead-free, zero-dimensional, organic-inorganic hybrid metal halide single crystal material. By utilizing high pressure, a crucial thermodynamic parameter and extreme conditions, the material achieves fluorescence from scratch, achieving high-quality luminescence under high pressure. Furthermore, (N-AD)2BiCl6 emits bright violet light at 2-30 GPa, and (N-AD)2BiBr6 exhibits bright blue light at 2-20 GPa. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is the single crystal diffraction structure diagram of the material described in Example 1.

[0027] Figure 2 The following is the powder X-ray diffraction (PXRD) pattern of the material described in Example 1.

[0028] Figure 3 These are morphology images of the material described in Example 1 under different applied pressures.

[0029] Figure 4 This is the pressure-dependent absorption spectrum of the material described in Example 1.

[0030] Figure 5 This is the luminescence phenomenon of the material described in Example 1 under different applied pressures.

[0031] Figure 6 This is a graph of the fluorescence emission spectrum (PL) of the material described in Example 1 that is related to pressure.

[0032] Figure 7 This is the chromaticity (CIE) diagram of the material described in Example 1.

[0033] Figure 8 This is a thermogravimetric (TG) diagram showing how the mass of the material described in Example 1 changes with temperature.

[0034] Figure 9 This is the single crystal diffraction structure diagram of the material described in Example 2.

[0035] Figure 10 This is the powder X-ray diffraction (PXRD) pattern of the material described in Example 2.

[0036] Figure 11 These are morphology images of the material described in Example 2 under different applied pressures.

[0037] Figure 12 This is the pressure-dependent absorption spectrum of the material described in Example 2.

[0038] Figure 13 This is the luminescence phenomenon of the material described in Example 2 under different applied pressures.

[0039] Figure 14 This is a graph of the fluorescence emission spectrum (PL) of the material described in Example 2 that is related to pressure.

[0040] Figure 15 This is the chromaticity (CIE) diagram of the material described in Example 2.

[0041] Figure 16 This is a thermogravimetric (TG) diagram showing the change in mass of the material described in Example 2 with temperature. DETAILED DESCRIPTION

[0042] The present invention will be further described in detail below with reference to specific embodiments.

[0043] In the following embodiments:

[0044] (1) Single crystal structure analysis: SHELXS-97 was used to collect single crystal structure data, and VESTA software was used for refinement and modification.

[0045] (2) PXRD test: D8 ADVANCE X-ray diffractometer, using a copper X-ray tube (standard) radiation with a voltage of 40 kV and a current of 40 mA, and scanning diffraction in the range of 5-60° at a step size of 10° / min at room temperature.

[0046] (3) In-situ high-pressure test: In-situ high-pressure experiments were carried out in a symmetrical diamond top hammer unit. The T301 steel gasket was first pre-pressed to a thickness of 45 μm, and then a hole with an aperture of 150 μm was laser-drilled in the center of the gasket to serve as the sample chamber. The actual pressure was measured using standard ruby ​​fluorescence technology. Microscopic images and fluorescence images of the sample under high pressure were obtained using a camera (Canon Eos 5Dmark II) equipped with a microscope (Ecilipse TI-U, Nikon). We used a deuterium halogen lamp as the excitation light source and collected the absorption spectrum and PL spectrum of the material under high-pressure evolution using a modified fiber optic spectrometer (Ocean Optics, QE65000). At the same time, a high-resolution camera (Canon, Eos 5D Mark) was connected to the microscope to record the changes in the sample in the sample chamber.

[0047] (4) Thermogravimetric analysis: STA449F5 thermogravimetric analyzer.

[0048] Example 1

[0049] Solid Bi2O3 (0.1 mol / L, 140 mg) and N-acetylethylenediamine (0.1 mol / L, 30 mg) were mixed with 3 mL of 37% hydrochloric acid in a 5 mL beaker and dissolved by stirring at 25°C to obtain a mixed solution. 5 mL of methanol was then poured into a 20 mL beaker, and the 5 mL small beaker containing the mixed solution was placed into a 20 mL large beaker containing the methanol solution. The large beaker was sealed and allowed to stand for 3 days. A white block-like single crystal material (C4H 12 N2O)(C4H 11 N2O)BiCl6, recorded as (N-AD)2BiCl6.

[0050] Depend on Figure 1 From the single crystal diffraction pattern, we can see that the crystal structure of (N-AD)2BiCl6 is a zero-dimensional perovskite configuration. 3- The inorganic octahedron is octahedralized by the organic cation N-acetylethylenediamine (C4H 12 N2O) 2+ With (C4H11 N2O) + Separated into independent island structures. Specific unit cell parameters are shown in Table 2.

[0051] like Figure 2 As shown, the PXRD pattern of (N-AD)2BiCl6 after ball milling is consistent with the PXRD pattern of single crystal simulation, further confirming the structure of (N-AD)2BiCl6.

[0052] like Figure 3 As shown, the (N-AD)2BiCl6 bulk crystals are colorless and transparent. Under the conditions of applying a pressure of 0 to 23.05 GPa, the crystal morphology does not change significantly, and after the pressure is released, the crystal morphology does not change significantly (in the figure, R represents the released pressure).

[0053] according to Figure 4 The pressure-dependent absorption spectrum of (N-AD)2BiCl6 shows that the absorption edge of (N-AD)2BiCl6 expands with increasing applied pressure, specifically from 362nm to 384nm, and the calculated band gap decreases from 3.43eV to 3.23eV. After complete release of pressure, the absorption edge essentially returns to its initial state (368nm).

[0054] like Figure 5 As shown, (N-AD)2BiCl6 exhibits no noticeable luminescence at normal pressure. As the applied pressure gradually increases, (N-AD)2BiCl6 exhibits violet light emission that initially becomes strong and then weakens. The luminescence intensity reaches its peak at 13.48 GPa, and as the applied pressure continues to increase, the intensity gradually weakens. When the applied pressure reaches 28.63 GPa, the violet light emission disappears. Furthermore, there is no noticeable luminescence during the pressure release process.

[0055] according to Figure 6 The pressure-dependent PL spectrum of (N-AD)2BiCl6 shows that the (N-AD)2BiCl6 crystal shows obvious emission at 394 nm under applied pressure, and the intensity is the largest at 13.48 GPa.

[0056] like Figure 7 As shown in the CIE chromaticity diagram, the emission light of (N-AD)2BiCl6 is violet light.

[0057] like Figure 8 Thermogravimetric analysis shows that (N-AD)2BiCl6 has good thermal stability and does not decompose at around 350℃.

[0058] Example 2

[0059] Solid Bi2O3 (0.1 mol / L, 140 mg) and N-acetylethylenediamine (0.1 mol / L, 30 mg) were mixed with 3 mL of 48% hydrobromic acid in a 5 mL beaker and dissolved by stirring at 25°C to obtain a mixed solution. 5 mL of methanol was then poured into a 20 mL beaker, and the 5 mL small beaker containing the mixed solution was placed into a 20 mL large beaker containing the methanol solution. The large beaker was sealed and allowed to stand for 3 days. A white block-like single crystal material (C4H 12 N2O)(C4H 11 N2O)BiBr6, recorded as (N-AD)2BiBr6.

[0060] Depend on Figure 9 From the single crystal diffraction pattern, we can see that the crystal structure of (N-AD)2BiBr6 is a zero-dimensional perovskite configuration. 3- The inorganic octahedron is octahedralized by the organic cation N-acetylethylenediamine (C4H 12 N2O) 2+ With (C4H 11 N2O) + Separated into independent island structures. Specific unit cell parameters are shown in Table 2.

[0061] like Figure 10 As shown in Figure 3, the PXRD pattern of (N-AD)2BiBr6 after ball milling is consistent with the PXRD pattern of single crystal simulation, further confirming the structure of (N-AD)2BiBr6.

[0062] like Figure 11 As shown, the (N-AD)2BiBr6 bulk crystals are colorless and transparent. Under the conditions of applying a pressure of 0 to 19.15 GPa, the crystal morphology does not change significantly, and after the pressure is released, the crystal morphology does not change significantly (in the figure, R represents the released pressure).

[0063] according to Figure 12 The pressure-dependent absorption spectrum of (N-AD)2BiBr6 shows that the absorption edge of (N-AD)2BiBr6 expands with increasing applied pressure, specifically from 418nm to 480nm, and the calculated band gap decreases from 2.97eV to 2.58eV. After complete release of pressure, the absorption edge essentially returns to its initial state (429nm).

[0064] like Figure 13As shown, (N-AD)2BiBr6 exhibits no noticeable luminescence at normal pressure. As the applied pressure gradually increases, (N-AD)2BiBr6 exhibits blue light emission that initially becomes strong and then weakens. The luminescence intensity reaches its peak at 9.56 GPa, and as the applied pressure continues to increase, the intensity gradually weakens. When the applied pressure reaches 19.15 GPa, the violet light emission of (N-AD)2BiBr6 essentially disappears. Furthermore, the luminescence becomes weak during the pressure release process.

[0065] according to Figure 14 The pressure-dependent PL spectrum of (N-AD)2BiBr6 shows that the (N-AD)2BiBr6 crystal shows obvious emission at 447 nm under applied pressure, and the intensity is the largest at 9.56 GPa.

[0066] like Figure 15 As shown in the CIE chromaticity diagram, the emission light of (N-AD)2BiBr6 is blue light.

[0067] like Figure 16 Thermogravimetric analysis shows that (N-AD)2BiBr6 has good thermal stability and does not decompose at around 350°C.

[0068] Table 2 Unit cell parameters of (N-AD)2BiCl6 and (N-AD)2BiBr6

[0069]

[0070]

[0071] Comparative Example 1

[0072] Solid Bi2O3 (0.1mol / L, 140mg) and N-acetylethylenediamine (0.1mol / L, 30mg) were mixed with 3mL of 47% hydroiodic acid in a 5mL beaker and stirred to dissolve at 25℃. Then, 5mL of ether was poured into a 20mL beaker. The 5mL small beaker containing the hydrobromic acid mixture was placed into a 20mL large beaker containing ether solution. The large beaker was sealed and allowed to stand for 3 days. A rose-red needle-shaped single crystal material (C4H 12 N2O)(C4H 11 N2O)BiI6, recorded as (N-AD)2BiI6.

[0073] The PXRD results of the material show that it has a zero-dimensional perovskite structure.

[0074] The material has no obvious luminescence phenomenon under high pressure conditions, that is, no pressure-induced luminescence performance.

[0075] Comparative Example 2

[0076] Solid PbO (0.1 mol / L, 67 mg) and N-acetylethylenediamine (0.1 mol / L, 30 mg) were mixed with 3 mL of 47% hydroiodic acid in a 5 mL beaker and stirred to dissolve at 25 °C. Then, 5 mL of ether was poured into a 20 mL beaker. The 5 mL small beaker containing the hydroiodic acid mixture was placed into a 20 mL large beaker containing ether solution. The large beaker was sealed and allowed to stand for 3 days. A yellow rod-shaped single crystal material (C4H 12 N2O)2(C4H 11 N2O)2Pb3I 12 , recorded as (N-AD)4Pb3I 12 .

[0077] The PXRD results of the material show that it has a zero-dimensional perovskite structure.

[0078] The material has no obvious luminescence phenomenon under high pressure conditions, that is, no pressure-induced luminescence performance.

[0079] In summary, the invention includes but is not limited to the above embodiments. Any equivalent replacement or partial improvement made under the spirit and principle of the present invention shall be deemed to be within the scope of protection of the present invention.

Claims

1. A lead-free zero-dimensional organic-inorganic hybrid metal halide single crystal material, characterized by: The chemical formula of the material is (C4H 12 N2O)(C4H 11 N2O)BiCl6 or (C4H 12 N2O)(C4H 11 N2O)BiBr6;BiCl6 3- or BiBr6 3- The inorganic octahedron is octahedralized by the organic cation N-acetylethylenediamine (C4H 12 N2O) 2+ With (C4H 11 N2O) + Separated into independent island structures; the unit cell parameters of the single crystal material are shown in Table 1 below: Table 1 。 2. A method for preparing the lead-free zero-dimensional organic-inorganic hybrid metal halide single crystal material as claimed in claim 1, characterized in that: The method steps include: N-acetylethylenediamine and B-site metal oxide or B-site metal halide are added to a halogen acid solution, and an anti-solvent method is used to prepare a zero-dimensional organic-inorganic hybrid metal halide single crystal material; Wherein, the B-site metal oxide is Bi2O3; The B-site metal halide is BiCl3 or BiBr3; The halogen acid is hydrochloric acid or hydrobromic acid; The molar ratio of the N-acetylethylenediamine to the metal oxide at position B is 1:2 to 1:3; the molar ratio of the N-acetylethylenediamine to the metal halide at position B is 1:2 to 1:3; The molar ratio of the B-site metal oxide to the halogen acid is 1:1 to 3:1; the molar ratio of the B-site metal halide to the halogen acid is 1:1 to 3:1; The anti-solvent is methanol or ether; the volume ratio of the halogen acid to the anti-solvent is 3:5 to 5:

5.

3. An application of the zero-dimensional organic-inorganic hybrid metal halide single crystal material according to claim 1, characterized in that: The material is used as a pressure-induced luminescence material; The (C4H 12 N2O)(C4H 11 N2O)BiCl6 is used as a pressure-induced violet luminescent material at a pressure of 2~30GPa; The (C4H 12 N2O)(C4H 11 N2O)BiBr6 is used as a pressure-induced blue light emitting material at a pressure of 2~20GPa.

4. The use of a zero-dimensional organic-inorganic hybrid metal halide single crystal material as claimed in claim 3, characterized in that: The (C4H 12 N2O)(C4H 11 The pressure used for N2O)BiCl6 as a pressure-induced violet light emitting material is 12~18GPa.

5. The use of a zero-dimensional organic-inorganic hybrid metal halide single crystal material as claimed in claim 3, characterized in that: The (C4H 12 N2O)(C4H 11 N2O)BiBr6 is used as a pressure-induced blue light emitting material at a pressure of 7~12GPa.

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