Double-ligand lanthanide series metal-organic framework material and preparation method thereof

Abstract

The invention discloses a double-ligand lanthanide series metal-organic framework material and a preparation method thereof. The double-ligand lanthanide series metal-organic framework material is applied to emission of red light, green light and white light. The preparation method comprises the following steps: dissolving lanthanide metal ion salt, 5-(4-carboxyl-phenoxy) isophthalic acid and 1, 10-phenanthroline in a proper amount of deionized water, dropwise adding dilute nitric acid to adjust the pH value, transferring the mixed solution into a closed hydrothermal reaction kettle, and putting the hydrothermal reaction kettle into a constant-temperature blast drying oven for hydrothermal reaction; and centrifuging, washing and drying the collected product to finally obtain the Ln-MOFs luminescent material. The prepared emission material capable of emitting red light and green light has high quantum efficiency, and the white light emission material realizes white light emission under excitation of the wavelength of 365 nm; the fluorescent powder prepared from the material and organic silica gel are combined and coated on an LED chip of 365 nm, and white light with high color rendering index and low color temperature can be obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of phosphor preparation, and in particular relates to a dual-ligand lanthanide metal-organic framework material (Ln-MOFs) material and a preparation method thereof. Background Art

[0002] Lanthanide metal organic frameworks (Ln-MOFs) are the main research objects in luminescent MOFs materials (LMOFs). Since Ln ions have 4f orbital structures that are not filled with electrons, these 4f electrons can undergo ff or fd configuration transitions, presenting extremely rich energy level transitions. Ln-MOFs exhibit unique optical properties including high color purity, large Stokes shift values, visible colors, and relatively long luminescence lifetime and unique monochromaticity generated by ff transitions through antenna effects, and are widely used in white light emitting diode (WLED) materials.

[0003] Although white light emitting materials can be prepared by doping with phosphors in traditional technology, such methods generally require the phosphors to have a very high quenching temperature, uniform particle size, easy coating and the ability to be excited by light sources, which makes them unable to meet the requirements of modern technology for white light materials. The luminescent rare earth metal organic framework materials that emit white light prepared by doping with rare earth ions have the advantages of strong color tunability, high quantum yield and long luminescence lifetime, and therefore show attractive application prospects in the field of white light emitting materials.

[0004] Using MOFs as the matrix, we selected blue-light-emitting organic ligands and doped them with green-emitting Tb 3+ ions and red luminescent Eu 3+ ions, using antenna effect (ligand → Ln 3+ The method of using the synthesized Ln-MOFs material to prepare WLED has the following advantages: 1) single-phase material, no need to mix multiple phosphors, and easy preparation; 2) red light emission, which can improve the color rendering index of WLED and reduce the color temperature. Therefore, Ln-MOFs is expected to become the focus of future WLED research. Summary of the invention

[0005] The present invention proposes a method for preparing a Ln-MOFs white luminescent material and its WLED application on a near-ultraviolet chip. A second ligand 1,10-phenanthroline is added to a first ligand 5-(4-carboxyl-phenoxy)isophthalic acid, and then different lanthanide metal ion ratios are adjusted. A closed stainless steel polytetrafluoroethylene-lined hydrothermal reactor is used to perform a hydrothermal reaction in a constant temperature blast drying oven. The obtained powder is centrifugally cleaned and dried to finally obtain a white Ln-MOFs luminescent material powder.

[0006] The technical solution steps adopted by the present invention are as follows:

[0007] 1. A high quantum yield green and red light Ln-MOFs luminescent material

[0008] The preparation formula of green light Ln-MOFs luminescent material is Ln(cpioa)phen(Ln:Tb)

[0009] The preparation formula of red light Ln-MOFs luminescent material is Ln(cpioa)phen(Ln:Eu)

[0010] The luminescent material covers the visible light range of green light and red light respectively, and can emit bright green light and red light under ultraviolet light excitation. It is a white powder with good crystallinity and uniform particles.

[0011] The dual-ligand Ln(cpiao)phen with red and green light emission has higher fluorescence intensity and quantum efficiency than the single-ligand Ln(cpiao).

[0012] 2. A Ln-MOFs white light luminescent material:

[0013] The preparation formula of the luminescent material is LaTbEu(cpioa)phen(La 3+ :Tb 3+ :Eu 3+ =0.9740:0.0255:0.0005), the luminescent material covers the entire visible light range of blue light, green light and red light, and can emit bright white light under the excitation of ultraviolet light with a wavelength of 365nm. It is a white powder with good crystallinity and uniform particles. It is combined with organic silica gel and coated on a 365nm LED chip to encapsulate into a light-emitting device, and bright white lighting is achieved at a voltage of 3.0 to 3.4V.

[0014] Large proportion La 3+ The introduction of not only retains and enhances the blue light emission of the ligand, but also dilutes Tb 3+ and Eu 3+ The strong red and green light emission makes it possible to regulate white light.

[0015] There are two different forms of energy transfer in MOFs: (1) energy transfer between two organic ligands and (2) energy transfer between Tb 3 + 、Eu 3+ The energy transfer between them.

[0016] 2. A method for preparing Ln-MOFs luminescent materials, the steps of the method are as follows:

[0017] 1) 5-(4-carboxyl-phenoxy)isophthalic acid (H3cpioa), 1,10-phenanthroline (1,10-phen), lanthanide metal ion salts (La(NO3)3·6H2O, Tb(NO3)3·6H2O and Eu(NO3)3·6H2O) are placed in a reactor, and dilute nitric acid is added dropwise to adjust the pH value;

[0018] 2) Stir the mixed solution at room temperature for 30 minutes;

[0019] 3) The above solution was transferred to a stainless steel reactor lined with polytetrafluoroethylene and placed in a constant temperature forced air drying oven for hydrothermal reaction. The reaction temperature was controlled at 120° C. and the reaction time was controlled at 72 hours.

[0020] 4) The reacted powder was centrifugally washed with deionized water and anhydrous ethanol, and dried at 60° C. for 24 hours to obtain a single-phase Ln-MOFs material;

[0021] The inner wall of the hydrothermal reactor is made of polytetrafluoroethylene or PPL material, and the outer wall is made of stainless steel. The pressure in the reactor is controlled by the amount of solution added, and the reaction is carried out under high temperature and high pressure.

[0022] The obtained white powder particles emit green light, red light and white light under excitation of 322 nm, 325 nm and 365 nm, respectively.

[0023] 3. Application of single-phase Ln-MOFs luminescent materials in white light LEDs

[0024] The white powder has fine and uniform particles, good dispersibility and high crystallinity, and has a broad blue emission peak, a narrow green emission peak and a sharp red light emission spectrum within the range of 400 to 650 nm.

[0025] The light-emitting device obtained by combining Ln-MOFs luminescent material with organic silica gel and coating it on a 365nm LED chip package can emit white light (color rendering index: 85.4, color temperature: 4415K) at a voltage of 3.0 to 3.4V.

[0026] The method for preparing the WLED device comprises the following steps:

[0027] 1) Place the organic silica gel on a clean glass plate;

[0028] 2) weighing Ln-MOFs phosphor using an analytical balance, and uniformly mixing the weighed phosphor with organic silica gel;

[0029] 3) coating the mixed colloid substance on a 365nm LED chip;

[0030] 4) Place the coated LED in an oven at 120°C for two hours to cure.

[0031] The beneficial effects of the present invention are:

[0032] 1) The present invention prepares a new type of mixed Ln-MOFs material powder with white light emission through a simple hydrothermal synthesis method. The powder material has fine and uniform particles and good crystallinity. It emits an emission spectrum in the visible light range including blue light, green light and red light. Under the excitation of ultraviolet light with a wavelength of 365nm, the material can emit bright white light.

[0033] 2) The white phosphor produced by the method of the present invention can be applied to an LED chip excited by 365nm ultraviolet light to produce a white light LED with a high color rendering index (85.4) and a low color temperature (4415K). BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a schematic diagram of the structure of a hydrothermal reactor: 1-fixing screws, 2-upper end cover, 3-reactor body, 4-sealing gasket, 5-lower end cover, 6-lining cover, 7-lining;

[0035] Figure 2 The XRD spectra of the products La(cpioa)phen, Tb(cpioa)phen, Eu(cpioa)phen and LaTbEu(cpioa)phen obtained in Example 1 are shown;

[0036] Figure 3 It is the simulated structure of Ln(cpioa)phen-MOFs;

[0037] Figure 4 The infrared spectra of the products La(cpioa)phen, Tb(cpioa)phen, Eu(cpioa)phen and LaTbEu(cpioa)phen obtained in Example 1 are shown in FIG.

[0038] Figure 5 The X-ray photoelectron spectrum of the product LaTbEu(cpioa)phen obtained in Example 1: (a) full spectrum, (b) La 3d, (c) Tb 3d, and (d) Eu 3d;

[0039] Figure 6 is the X-ray photoelectron spectrum of the product LaTbEu(cpioa)phen obtained in Example 1: C1s, O1s and N1s;

[0040] Figure 7are thermogravimetric analysis graphs of the products obtained in Example 1, (a) La(cpioa)phen, (b) Tb(cpioa)phen, (c) Eu(cpioa)phen and (d) LaTbEu(cpioa)phen;

[0041] Figure 8 The fluorescence spectra of the products Tb(cpioa) and Tb(cpioa)phen, Eu(cpioa) and Eu(cpioa)phen obtained in Example 1 and the corresponding CIE spectra;

[0042] Fig. 9 is the CIE spectrum of the product obtained in Example 1, La(cpioa)phen, Tb(cpioa)phen, Eu(cpioa)phen;

[0043] Fig.10 is the energy transfer model of the product obtained in Example 1;

[0044] Fig.11 is the luminescence spectrum of the product LaTbEu(cpioa)phen obtained in Example 1;

[0045] Fig.12 is the CIE spectrum corresponding to the product obtained in Example 1;

[0046] Fig.13 This is the WLED photoelectric parameter luminescence spectrum of the product obtained in Example 1. Specific implementation methods

[0048] like Figure 1 The stainless steel reactor for hydrothermal reaction of the present invention is shown, the inner lining 7 of the reactor body 3 is made of polytetrafluoroethylene or PPL material, the upper end surface of the inner lining 7 is provided with an inner lining cover 6, the lower end cover 5 and the upper end cover 2 installed by the fixing screw 1 are provided above the inner lining cover 6, and the lower end cover 5 and the reactor body 3 are sealed by a sealing gasket 4. The present invention transfers the prepared reaction solution to the hydrothermal reactor, and the solute molecules react under high temperature and high pressure to finally generate MOFs powder. The preparation formula of the luminescent powder is LaTbEu(cpioa)phen, and the powder material emits bright white light under the excitation of 365nm ultraviolet light. It is packaged into a light-emitting device with an LED chip, and bright white lighting is achieved at a voltage of 3.0 to 3.4V.

[0049] Embodiment 1:

[0050] Preparation of Ln-MOFs luminescent materials:

[0051] Take 8.6602g La(NO3)3·6H2O and dissolve it in 100mL deionized water to make a La solution with a molar concentration of 0.2mol / L. 3+Then, 9.0606g and 2.7182g of Tb(NO3)3·6H2O were dissolved in 100mL of deionized water to prepare Tb solutions with molar concentrations of 0.2mol / L and 0.06mol / L, respectively. 3+ Finally, 8.9200 g and 4.46 mg of Eu(NO3)3·6H2O were dissolved in 100 mL of deionized water to prepare La solutions with molar concentrations of 0.2 mol / L and 0.0001 mol / L, respectively. 3+ Solution. Dissolve 6.62 mL of concentrated nitric acid in 100 mL of deionized water to prepare a dilute nitric acid solution with a molar concentration of 1 mol / L.

[0052] 1) Preparation of La(cpioa)phen: Take 0.6mmol of 0.2mol / L La 3+ The solution was prepared in 3 mL, and 0.3 mmol of 5-(4-carboxy-phenoxy)isophthalic acid (0.0901 g) and 1,10-phenanthroline (0.0541 g) were weighed respectively.

[0053] 2) Preparation of Tb(cpioa)phen: Take 0.6mmol of 0.2mol / L Tb 3+ The solution was prepared in 3 mL, and 0.3 mmol of 5-(4-carboxy-phenoxy)isophthalic acid (0.0901 g) and 1,10-phenanthroline (0.0541 g) were weighed respectively.

[0054] 3) Preparation of Eu(cpioa)phen: Take 0.6mmol of 0.2mol / L Eu 3+ The solution was prepared in 3 mL, and 0.3 mmol of 5-(4-carboxy-phenoxy)isophthalic acid (0.0901 g) and 1,10-phenanthroline (0.0541 g) were weighed respectively.

[0055] 4) Preparation of LaTbEu(cpioa)phen: Take 0.5844mmol of 0.2mol / L La 3+ Solution 2.922mL, take 0.0153mmol 0.06mol / L Tb 3+ 0.26 mL of solution, take 0.0003 mmol of 0.0001 mol / L La 3+ Solution 3mL, and then weigh 0.3mmol of 5-(4-carboxy-phenoxy)isophthalic acid 0.0901g and 1,10-phenanthroline 0.0541g respectively.

[0056] Dissolve the four groups of samples in a beaker filled with 50mL of deionized water and stir. During the stirring process, add about 1mol / L of dilute nitric acid solution to adjust the pH of the mixed solution to 6.0 and stir for about 30min. After stirring, transfer the mixed solution to a 100mL stainless steel reactor lined with polytetrafluoroethylene, with a filling degree of about 60%. Place the three reactors in a constant temperature blast drying oven, set the reaction time to 72 hours, and the reaction temperature to 120°C for hydrothermal reaction. After the reaction is completed, centrifuge and wash three times with deionized water, place the centrifuged product in a constant temperature drying oven, and dry it at 60°C for 24 hours. Finally, four white crystalline materials with uniform particle size are obtained, La(cpioa)phen, Tb(cpioa)phen, Eu(cpioa)phen and LaTbEu(cpioa)phen.

[0057] Figure 2 The product obtained in this example is Ln(cpioa)phen(Ln:La 3+ ,Tb 3+ and Eu 3+ ) and LaTbEu(cpioa)phen. The XRD patterns of the prepared samples are consistent with the simulated patterns. Adding the auxiliary ligand 1,10-phen can improve the crystallinity of a given sample. The reason for this may be that during the coordination process between Ln(cpioa) and 1,10-phen, the N atom in 1,10-phen may replace the N atom in the coordination process with Ln(cpioa). 3+ Ions coordinate water molecules, thereby expanding the conjugated system of MOFs and improving crystallinity.

[0058] Figure 3 The simulated structure of Ln(cpioa)phen-MOFs based on XRD pattern analysis is shown.

[0059] like Figure 4 As shown, 3070cm -1 The peaks near are attributed to the CH stretching vibrations on the ligand benzene ring. In Ln(cpioa)phen, the peaks at 1723 cm -1 There is no absorption peak at , indicating that H3cpioa is completely deprotonated to cpioa 3+ , and with Ln 3+ Coordination. 1,10-phen at 1421cm -1 The C=N stretching vibration peak at 1,10-phen disappears, which may be due to the nitrogen atom in 1,10-phen and Ln 3 + Ion coordination. 3+ After ion coordination, the asymmetry of -COOH (ν as ) and symmetry (ν s) stretching vibration peaks from 1280cm -1 Move to 1387cm -1 and 1423cm -1 Up to 1536cm -1 Therefore, it can be concluded that Ln ions successfully coordinated with O and N atoms in the Ln(cpio)phen-MOFs framework.

[0060] Figure 5 , Figure 6 This is the X-ray photoelectron spectrum of the MOFs powder. From the XPS results, it can be concluded that H3cpioa binds to La in both ionic and covalent ways. 3+ , Tb 3+ and Eu 3+ There is no redox reaction in the coordination process. At the same time, the C1s, O1s and N1s spectra show that La 3+ , Tb 3+ and Eu 3+ Bonds to the O and N atoms on -COO- and C=N in the ligand.

[0061] Figure 7 This is the thermogravimetric analysis (TG) diagram of the Ln-MOFs powder. As shown in the figure, all given samples experienced a similar weight loss process: the first weight loss step (weight loss of 12.57%) occurred between 25 and 112°C, which may correspond to the removal of surface water molecules. The second weight loss step (weight loss of 13.43%) occurred between 112 and 439°C, which may correspond to the removal of structural water molecules within the framework. The third step of weight loss (weight loss of 45.74%) occurred between 439 and 517°C, and the weight loss may be due to framework collapse (weight loss of 47.72%). The TG results show that the prepared Ln-MOFs have good enough thermal stability and are suitable for WLED applications.

[0062] Figure 8 The fluorescence spectra of Tb(cpioa) and Tb(cpioa)phen, Eu(cpioa) and Eu(cpioa)phen and the corresponding CIE spectra are shown in Table 1 below. The fluorescence intensity and quantum efficiency of Tb(cpioa) and Tb(cpioa)phen, Eu(cpioa) and Eu(cpioa)phen are shown in Table 1 below.

[0063] Table 1

[0064]

[0065] As can be seen from the table above, the dual-ligand Ln-MOF has a higher emission intensity than the single-ligand Ln-MOF. The emission intensity and quantum efficiency of Tb(cpioa)phen are about 21 times and 5 times higher than those of Tb(cpioa), respectively. The emission intensity and quantum efficiency of Eu(cpioa)phen are about 34 times and 36 times higher than those of Eu(cpioa), respectively. The inset shows that the brightness of the dual-ligand Ln(cpioa)phen is much higher than that of the single-ligand Ln(cpioa).

[0066] Weigh 0.06g of the obtained LaTbEu(cpioa)phen phosphor with weighing paper for later use. Then weigh 0.5g of organic silica gel on a glass plate and pour the weighed LaTbEu(cpioa)phen on the organic silica gel. Use a glass rod to evenly stir and mix the phosphor and organic silica gel. Apply the mixed adhesive material on a 365nm LED chip, put it in a 120℃ constant temperature drying oven and dry it for two hours. After it solidifies, a WLED is obtained.

[0067] Fig. 9 The CIE chromaticity diagram of La(cpioa)phen, Tb(cpioa)phen, and Eu(cpioa)phen shows that the three fall in the blue, green, and red regions, respectively. 3+ , Tb 3+ and Eu 3+ ratio, white light emission can be achieved.

[0068] Fig.10 is a model for simulating energy transfer in LaTbEu(cpioa)phen. For the organic ligands in LaTbEu(cpioa)phen, there are two pathways for energy transfer: (i) through the energy transfer process, energy is transferred from the lowest singlet state (S1) of H3cpioa to the S1 of 1,10-phen, then from the S1 of 1,10-phen to the lowest triplet state (T1) of 1,10-phen, and finally to Ln 3+ (ii) Through the ISC process, energy is transferred from S1 of H3cpioa to T1 of H3cpioa, then from T1 of H3cpioa to T1 of 1,10-phen, and finally to Ln 3+ For the organic ligands and metal ions in LaTbEu(cpioa)phen, part of the energy absorbed by the organic ligands is directly transferred to Tb 3+ and Eu 3+ Ion, Tb 3+ Then transfer part of the energy to Eu 3+ ions, so only a small amount of Eu3+ White light can be modulated.

[0069] Depend on Fig.11 It can be seen that the luminescent material prepared by the present invention can emit characteristic peaks of Tb and Eu;

[0070] Fig.12 The CIE chromaticity diagram of LaTbEu(cpioa)phen shows that the coordinates are (0.323, 0.343), which is very close to pure white light (0.333, 0.333). This proves that the Ln-MOFs white phosphor was successfully synthesized.

[0071] Fig.13 This is the photoelectric parameter performance diagram of the WLED. It can be seen that the WLED made with this phosphor and near-ultraviolet LED chip has a high color rendering index of 85.4 and a relatively low color temperature of 4415K.

[0072] Embodiment 2:

[0073] Preparation of Ln-MOFs luminescent materials:

[0074] Take 8.6602g La(NO3)3·6H2O and dissolve it in 100mL deionized water to make a La solution with a molar concentration of 0.2mol / L. 3+ Then, 9.0606g and 2.7182g of Tb(NO3)3·6H2O were dissolved in 100mL of deionized water to prepare Tb solutions with molar concentrations of 0.2mol / L and 0.06mol / L, respectively. 3+ Finally, 8.9200 g and 4.46 mg of Eu(NO3)3·6H2O were dissolved in 100 mL of deionized water to prepare La solutions with molar concentrations of 0.2 mol / L and 0.0001 mol / L, respectively. 3+ Solution. Dissolve 6.62 mL of concentrated nitric acid in 100 mL of deionized water to prepare a dilute nitric acid solution with a molar concentration of 1 mol / L.

[0075] 1) Preparation of La(cpioa)phen: Take 0.6mmol of 0.2mol / L La 3+ The solution was prepared in 3 mL, and 0.3 mmol of 5-(4-carboxy-phenoxy)isophthalic acid (0.0901 g) and 1,10-phenanthroline (0.0541 g) were weighed respectively.

[0076] 2) Preparation of Tb(cpioa)phen: Take 0.6mmol of 0.2mol / L Tb 3+ 3 mL of the solution was added, and then 0.3 mmol of 5-(4-carboxyl-phenoxy)isophthalic acid (0.0901 g) and 1,10-phenanthroline (0.0541 g) were weighed respectively.

[0077] 3) Preparation of Eu(cpioa)phen: Take 0.6mmol of 0.2mol / L Eu 3+ The solution was prepared in 3 mL, and 0.3 mmol of 5-(4-carboxy-phenoxy)isophthalic acid (0.0901 g) and 1,10-phenanthroline (0.0541 g) were weighed respectively.

[0078] 4) Preparation of LaTbEu(cpioa)phen: Take 0.5844mmol of 0.2mol / L La 3+ Solution 2.922mL, take 0.0153mmol 0.06mol / L Tb 3+ 0.26 mL of solution, take 0.0003 mmol of 0.0001 mol / L La 3+ Solution 3mL, and then weigh 0.3mmol of 5-(4-carboxy-phenoxy)isophthalic acid 0.0901g and 1,10-phenanthroline 0.0541g respectively.

[0079] Dissolve the four groups of samples in a beaker filled with 35mL of deionized water and stir. During the stirring process, add about 1mol / L of dilute nitric acid solution to adjust the pH of the mixed solution to 6.0 and stir for about 30min. After stirring, transfer the mixed solution to a 100mL stainless steel reactor lined with polytetrafluoroethylene, with a filling degree of about 50%. Place the three reactors in a constant temperature blast drying oven, set the reaction time to 72 hours, and the reaction temperature to 120°C for hydrothermal reaction. After the reaction is completed, centrifuge and wash three times with deionized water, place the centrifuged product in a constant temperature drying oven, and dry it at 60°C for 24 hours. Finally, four portions of white crystalline materials with uniform particle size, La(cpioa)phen, Tb(cpioa)phen, Eu(cpioa)phen and LaTbEu(cpioa)phen, are obtained.

[0080] Embodiment 3:

[0081] Preparation of Ln-MOFs luminescent materials:

[0082] Take 8.6602g La(NO3)3·6H2O and dissolve it in 100mL deionized water to make a La solution with a molar concentration of 0.2mol / L. 3+ Then, 9.0606g and 2.7182g of Tb(NO3)3·6H2O were dissolved in 100mL of deionized water to prepare Tb solutions with molar concentrations of 0.2mol / L and 0.06mol / L, respectively. 3+ Finally, 8.9200 g and 4.46 mg of Eu(NO3)3·6H2O were dissolved in 100 mL of deionized water to prepare La solutions with molar concentrations of 0.2 mol / L and 0.0001 mol / L, respectively.3+ Solution. Dissolve 6.62 mL of concentrated nitric acid in 100 mL of deionized water to prepare a dilute nitric acid solution with a molar concentration of 1 mol / L.

[0083] 1) Preparation of La(cpioa)phen: Take 0.6mmol of 0.2mol / L La 3+ The solution was prepared in 3 mL, and 0.3 mmol of 5-(4-carboxy-phenoxy)isophthalic acid (0.0901 g) and 1,10-phenanthroline (0.0541 g) were weighed respectively.

[0084] 2) Preparation of Tb(cpioa)phen: Take 0.6mmol of 0.2mol / L Tb 3+ 3 mL of the solution was added, and then 0.3 mmol of 5-(4-carboxyl-phenoxy)isophthalic acid (0.0901 g) and 1,10-phenanthroline (0.0541 g) were weighed respectively.

[0085] 3) Preparation of Eu(cpioa)phen: Take 0.6mmol of 0.2mol / L Eu 3+ The solution was prepared in 3 mL, and 0.3 mmol of 5-(4-carboxy-phenoxy)isophthalic acid (0.0901 g) and 1,10-phenanthroline (0.0541 g) were weighed respectively.

[0086] 4) Preparation of LaTbEu(cpioa)phen: Take 0.5844mmol of 0.2mol / L La 3+ Solution 2.922mL, take 0.0153mmol 0.06mol / L Tb 3+ 0.26 mL of solution, take 0.0003 mmol of 0.0001 mol / L La 3+ Solution 3mL, and then weigh 0.3mmol of 5-(4-carboxy-phenoxy)isophthalic acid 0.0901g and 1,10-phenanthroline 0.0541g respectively.

[0087] Dissolve the four groups of samples in a beaker filled with 50mL of deionized water and stir. During the stirring process, add about 1mol / L of dilute nitric acid solution to adjust the pH of the mixed solution to 6.0 and stir for about 30min. After stirring, transfer the mixed solution to a 100mL stainless steel reactor lined with polytetrafluoroethylene, with a filling degree of about 60%. Place the three reactors in a constant temperature blast drying oven, set the reaction time to 72 hours, and the reaction temperature to 130°C for hydrothermal reaction. After the reaction is completed, centrifuge and wash three times with deionized water, place the centrifuged product in a constant temperature drying oven, and dry it at 60°C for 24 hours. Finally, four white crystalline materials with uniform particle size are obtained, La(cpioa)phen, Tb(cpioa)phen, Eu(cpioa)phen and LaTbEu(cpioa)phen.

[0088] The specific test results of the prepared Ln-MOFs are similar to the test results of Example 1.

Claims

1. A dual-ligand lanthanide metal-organic framework material with green, red and white light emission, characterized in that: The dual ligand lanthanide metal-organic framework material is Ln(cpiao)phen, wherein the dual ligand Ln(cpiao)phen that emits red light is Eu(cpioa)phen, the dual ligand Ln(cpiao)phen that emits green light is Tb(cpioa)phen, and the dual ligand Ln(cpiao)phen that emits white light is LaTbEu(cpioa)phen; The first ligand and the second ligand in the dual ligand are 5-(4-carboxyl-phenoxy)isophthalic acid and 1,10-phenanthroline respectively.

2. The dual-ligand lanthanide metal-organic framework material having green light, red light and white light emission according to claim 1, characterized in that: By adjusting La 3+ , Tb 3+ and Eu 3+ The luminescence color of the material can be controlled by adjusting the ratio of ions. La in the dual-ligand lanthanide metal-organic framework material with white light emission 3+ , Tb 3+ and Eu 3+ The molar ratio of the ions is 0.9740:0.0255:0.0005; LaTbEu(cpioa)phen has white light emission under excitation at a wavelength of 365nm.

3. The dual-ligand lanthanide metal-organic framework material having green light, red light and white light emission according to claim 1, characterized in that: The fluorescence intensity of Tb(cpioa)phen emitting green light is 5.3×10 5 The quantum efficiency reached 15.43%, and the fluorescence intensity of the red-light-emitting Eu(cpioa)phen was 9.4ⅹ10 5 , quantum efficiency reaches 36.37%.

4. A light-emitting device prepared using the dual-ligand lanthanide metal-organic framework material according to claim 1, characterized in that: The white light emitting phosphor LaTbEu(cpioa)phen is combined with organic silica gel and coated on a 365nm ultraviolet LED chip to encapsulate a light-emitting device. At a voltage of 3.0 to 3.4V, the light-emitting device emits bright white light with a color rendering index of 85.4 and a color temperature of 4415K.

5. The method for preparing the dual-ligand lanthanide metal-organic framework material with green light, red light and white light emission according to claim 1, characterized in that: The following steps are involved: Step 1: preparing a lanthanide ion solution: weighing an appropriate amount of lanthanide metal ion salt and dissolving it in deionized water, stirring to obtain a lanthanide ion solution; Step 2: dissolving the lanthanide ion solution prepared in step 1 and two organic small molecule ligands in deionized water respectively, stirring and mixing at room temperature, and adding 1 mol / L dilute nitric acid dropwise during stirring to adjust the pH of the mixed solution; Step 3: The mixed solution of step 2 is transferred to a stainless steel reactor lined with polytetrafluoroethylene, and placed in a constant temperature forced air drying oven for hydrothermal reaction; Step 4: The powder obtained after the reaction in step 3 is washed with deionized water, and then dried to obtain the Ln(cpiao)phen luminescent material.

6. The method for preparing a dual-ligand lanthanide metal-organic framework material according to claim 5, characterized in that: When preparing dual-ligand lanthanide metal-organic framework materials with green light emission: The preparation method of the lanthanide ion solution in step 1 is: weigh an appropriate amount of Tb(NO3)3·6H2O and dissolve it in deionized water, stir, and prepare 0.3 mol / L Tb 3+ ; When preparing dual-ligand lanthanide metal-organic framework materials with red light emission: The preparation method of the lanthanide ion solution in step 1 is: weigh an appropriate amount of Eu(NO3)3·6H2O and dissolve it in deionized water, stir it, and prepare it into 0.3 mol / L Tb 3+ ; In the step 2), the two organic small molecule ligands are 5-(4-carboxyl-phenoxy)isophthalic acid and 1,10-phenanthroline, 5-(4-carboxyl-phenoxy)isophthalic acid, and the molar ratio of 5-(4-carboxyl-phenoxy)isophthalic acid, 1,10-phenanthroline and the metal central ion is 1:1:

2.

7. The method for preparing a dual-ligand lanthanide metal-organic framework material according to claim 5, characterized in that: When preparing dual-ligand lanthanide metal-organic framework materials with white light emission: The preparation method of the lanthanide ion solution in step 1 is: weigh appropriate amounts of La(NO3)3·6H2O, Tb(NO3)3·6H2O and Eu(NO3)3·6H2O, dissolve them in deionized water, stir, and prepare them into 0.2 mol / L La 3+ 、0.06mol / L Tb 3+ and 0.0001mol / L Eu 3+ ; In the step 2), the two organic small molecule ligands are 5-(4-carboxyl-phenoxy)isophthalic acid and 1,10-phenanthroline, 5-(4-carboxyl-phenoxy)isophthalic acid, the molar ratio of 5-(4-carboxyl-phenoxy)isophthalic acid, 1,10-phenanthroline and the metal central ion is 1:1:2, and the metal central ion La 3+ , Tb 3+ and Eu 3+ The molar ratio is 0.9740:0.0255:0.0005.

8. The method for preparing a dual-ligand lanthanide metal-organic framework material according to claim 5, characterized in that: In the step 2), the pH of the mixed solution is adjusted to 5-6 with dilute nitric acid.

9. The method for preparing a dual-ligand lanthanide metal-organic framework material according to claim 5, characterized in that: In the step 3), the stainless steel reactor is lined with polytetrafluoroethylene or PPL material, the shell is made of stainless steel material, and the filling amount of the mixed solution accounts for 45% to 65% of the volume of the reactor lining; the reaction temperature of the hydrothermal reaction is controlled at 120° C., and the reaction time is controlled at 72 hours.

10. The method for preparing a dual-ligand lanthanide metal-organic framework material according to claim 5, characterized in that: In the step 4), the drying condition is drying at 60° C. for 24 hours.

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