An organic-inorganic hybrid luminescent halide material and its preparation method and application

Abstract

The present invention discloses an organic-inorganic hybrid luminescent halide material, its preparation method, and application, belonging to the technical field of luminescent materials. The organic-inorganic hybrid luminescent halide material has the general chemical formula AL6ACl6, where A is a lanthanide ion and L is N,N'-dimethylurea or N,N'-diethylurea. The present invention also discloses a preparation method and application of the organic-inorganic hybrid luminescent halide material. The organic-inorganic hybrid luminescent halide material of the present invention can be stably present in an atmospheric environment with a relative humidity of less than 65%, solving the problem of poor air and humidity stability of existing lanthanide-based organic-inorganic hybrid halides and having broad application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of luminescent materials, and in particular relates to an organic-inorganic hybrid luminescent halide material and a preparation method and application thereof. Background Art

[0002] In recent years, zero-dimensional (0D) halide perovskites have become a research hotspot for luminescent materials due to their superior optoelectronic properties. Unlike three-dimensional (3D) perovskites, 0D halide perovskites are composed of isolated metal halide octahedra (PbX6 3- 、SbX6 3- 、SnX6 3- 0D halide perovskites are composed of ions (e.g., X = Cl, Br, I), separated by organic or inorganic cations. This unique structure hinders exciton migration, reduces non-radiative transitions, and achieves a high photoluminescence quantum yield (PLQY). Importantly, the introduction of 0D halide perovskites effectively improves the structural and photoluminescence stability of the material; due to the lack of a continuous metal halide framework, 0D halide perovskites exhibit better wet, optical, and thermal structural stability than 3D halide perovskites. Furthermore, organic cations play an important role in 0D halide perovskites, not only enabling structural size modulation but also enhancing structural stability through abundant hydrogen bonding and van der Waals effects. These properties make 0D halide perovskites attractive candidates for lighting, sensing, display, blinking, and anti-counterfeiting applications.

[0003] Lanthanide elements are widely used in optoelectronic fields such as solid-state lighting, display devices, bioimaging, and anti-counterfeiting labels due to their unique 4f–4f transition mechanism, narrowband emission characteristics, and long-lived excited states. Lanthanide ions play an irreplaceable role in the design of novel functional materials, especially in the construction of high-color-purity and high-quantum-efficiency luminescent materials. Recent studies have found that 0D lanthanide halide perovskites (Cs3TbCl6, Rb3TbCl6, and Cs3CeBr6) have been developed for use in LEDs and scintillators, exhibiting ultra-high PLQY. In addition, by incorporating organic cations into lanthanide ions, lanthanide-based organic-inorganic hybrid halides have achieved high PLQY and good mechanical processing properties. However, similar to 0D lanthanide halide perovskites, lanthanide-based organic-inorganic hybrid halides also suffer from severe air / humidity instability, especially [LnCl6] 3- (Ln = lanthanide ion) The structural unit is easily hydrolyzed and undergoes structural collapse after exposure to air, which leads to a sharp decay of luminescence performance, severely limiting its application in devices in open environments.

[0004] To isolate the structure from moisture, early lanthanide-based organic-inorganic hybrid halide materials were typically synthesized in a moisture-free environment. In recent years, preparation methods such as temperature-assisted solution volatilization and temperature-assisted inverse crystallization have also been developed for lanthanide-based organic-inorganic hybrid halide materials. However, these methods often have complex reaction conditions and are highly equipment-dependent, making them difficult to achieve large-scale, green synthesis.

[0005] Therefore, there is an urgent need to develop a molecular-scale waterproofing strategy that is structurally clear, mechanistically controllable, operationally simple, and universal, so that rare earth halide-based luminescent materials can achieve long-term, efficient, and stable luminescence in air without sacrificing their excellent optical properties. Furthermore, this strategy should be scalable and applicable to different types of rare earth ions and crystal coordination environments to meet the diverse needs of practical device applications. Summary of the Invention

[0006] The problem to be solved by the present invention is to provide an organic-inorganic hybrid luminescent halide material and its preparation method and application, so as to solve the problem of poor air stability and humidity stability of existing lanthanide-based organic-inorganic hybrid halides.

[0007] The technical solution adopted to solve the technical problem is an organic-inorganic hybrid luminescent halide material. The chemical formula of the organic-inorganic hybrid luminescent halide material is AL6ACl6, where A is a lanthanide ion and L is N,N'-dimethylurea or N,N'-diethylurea.

[0008] The beneficial effects of the above technical solution of the present invention are as follows: the organic-inorganic hybrid luminescent halide material of the present invention has good air stability and humidity stability. Its mechanism of action is mainly that: the organic ligand L in the chemical formula has a highly symmetrical molecular structure, and two different functional groups (urea and amino) are located on the upper and lower sides of the alkane chain; the urea functional group is negatively charged and forms [AL6] with some isolated lanthanide ions (A ions). 3+ cations, while the other part of the A ions and chloride ions form a negatively charged [ACl6] 3- The octahedron balances the charge and is attracted to the positively charged amino groups to form hydrogen bonds; [AL6] 3+ with [ACl6] 3- The octahedra are arranged alternately to form a zero-dimensional perovskite-like structure. Furthermore, the organic ligand L constructs two pseudo-molecular cage structures to form two pseudo-molecular cage structures for isolated A ions and [ACl6] 3- The octahedron provides spatial separation and protection; at the same time, the abundant hydrogen bonding between the organic ligands L prevents the erosion of water molecules in the air. When L is N,N'-diethylurea, the extended alkane chain makes this organic-inorganic hybrid lanthanide luminescent halide material more air-stable.

[0009] Preferably, the lanthanide ion is Tb 3+ 、Eu 3+ or Ce 3+ .

[0010] Preferably, the organic-inorganic hybrid luminescent halide material has a pseudo-molecular cage structure.

[0011] The present invention also provides a method for preparing the above-mentioned organic-inorganic hybrid luminescent halide material, which uses L and the compound ACl3·xH2O as raw materials and adopts a solution volatilization method or a mechanical grinding method for preparation.

[0012] Preferably, the compound ACl3·xH2O is TbCl3·6H2O, EuCl3·6H2O or CeCl3·7H2O.

[0013] Preferably, the solution volatilization method comprises the following steps:

[0014] L and compound ACl3·xH2O are used as raw materials, a solvent is added and mixed, and then the mixture is allowed to stand for the solvent to evaporate, thereby obtaining a crystal of an organic-inorganic hybrid luminescent halide material.

[0015] More preferably, the molar ratio of ACl3·xH2O and L is 1:3; the solvent is methanol, ethanol or acetone; and the ratio of the solvent volume to the total mass of ACl3·xH2O and L is 10-20 mL:1 g.

[0016] Preferably, the mechanical grinding method comprises the following steps:

[0017] L and compound ACl3·xH2O are used as raw materials, a solvent is added dropwise and then ground to obtain polycrystalline powder of an organic-inorganic hybrid luminescent halide material.

[0018] More preferably, the molar ratio of ACl3·xH2O and L is 1:3; the solvent is methanol, ethanol or acetone; the ratio of the solvent volume to the total mass of ACl3·xH2O and L is 0.05~0.2mL:1g; and the grinding time is 8~12min.

[0019] The present invention also provides applications of the organic-inorganic hybrid luminescent halide material in the preparation, display and anti-counterfeiting of optoelectronic devices.

[0020] The present invention has the following beneficial effects:

[0021] (1) The organic-inorganic hybrid luminescent halide material of the present invention can exist stably in an atmospheric environment with a relative humidity of less than 65%, and its pseudo-molecular cage structure has a significant effect on improving the structural stability of the material; the pseudo-molecular cage structure formed by the organic ligands in the structure has a significant effect on the stability of isolated lanthanide ions and [ACl6] 3-The octahedron forms a good coating, which greatly improves the air stability of the material and solves the problem of poor air stability of lanthanide-based organic-inorganic hybrid luminescent halide materials.

[0022] (2) The organic-inorganic hybrid luminescent halide material of the present invention can be directly prepared into crystals and polycrystalline powders by solution volatilization and mechanical grinding in an atmospheric atmosphere, breaking through the limitation that traditional lanthanide organic-inorganic hybrid halide materials need to be prepared at high temperatures; the preparation method is simple and can meet the diverse needs in actual device applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a diagram of the mechanical grinding preparation process of [Tb(DEU)6]TbCl6 in Example 2;

[0024] Figure 2 Figures are bonding analysis diagrams; (a) is the electrostatic potential distribution diagram of N,N'-dimethylurea molecules and N,N'-diethylurea molecules; (b) is the specific bonding diagram of N,N'-diethylurea molecules in [Tb(DEU)6]TbCl6 in Example 1;

[0025] Figure 3 The crystal structure of [Tb(DMU)6]TbCl6 of Example 3;

[0026] Figure 4 The crystal structure of [Tb(DEU)6]TbCl6 of Example 1;

[0027] Figure 5 Figures 1 and 2 show the structures of two pseudo-molecular cages in the [Tb(DEU)6]TbCl6 crystal of Example 1; (a) shows the structure of cage 1; (b) shows the structure of cage 2.

[0028] Figure 6 % volume calculation diagram; wherein, (a) is the percentage volume calculation diagram of [Tb(DMU)6]TbCl6 of Example 3; (b) is the percentage volume calculation diagram of [Tb(DEU)6]TbCl6 of Example 1;

[0029] Figure 7 The Hirshfeld surface analysis diagram and two-dimensional fingerprint diagram of [Tb(DEU)6]TbCl6 of Example 1; wherein, (a) is a schematic diagram of the molecular structure; (b) is a total distance distribution diagram; (c) is a H···H distribution diagram; (d) is a H···Cl distribution diagram;

[0030] Figure 8The Hirshfeld surface analysis diagram and two-dimensional fingerprint diagram of [Tb(DMU)6]TbCl6 of Example 3; wherein, (a) is a schematic diagram of the molecular structure; (b) is a total distance distribution diagram; (c) is a H···H distribution diagram; (d) is a H···Cl distribution diagram;

[0031] Figure 9 XRD diffraction data diagram; wherein, (a) is [Tb(DEU)6]TbCl6 of Example 1; (b) is [Tb(DMU)6]TbCl6 of Example 3; (c) is (DMA)4TbCl7 of Comparative Example 1;

[0032] Figure 10 This is a graph showing the change in photoluminescence quantum yield of [Tb(DEU)6]TbCl6 in Example 1. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. That is, the embodiments described are only part of the embodiments of the present invention, rather than all embodiments.

[0034] Example 1

[0035] An organic-inorganic hybrid luminescent halide material with the general chemical formula [Tb(DEU)6]TbCl6, where DEU is C5H 12 N2O.

[0036] This embodiment also includes a method for preparing the above-mentioned organic-inorganic hybrid luminescent halide material, comprising the following steps:

[0037] (1) Weigh 0.174 g of N,N'-diethylurea and 0.187 g of TbCl3·6H2O, add 5 mL of methanol and mix well to obtain a clear mixed solution;

[0038] (2) The mixed solution is placed in a fume hood to evaporate the methanol for 5 hours, and a transparent organic-inorganic hybrid luminescent halide material crystal is obtained, namely [Tb(DEU)6]TbCl6 crystal.

[0039] Example 2

[0040] An organic-inorganic hybrid luminescent halide material with the general chemical formula [Tb(DEU)6]TbCl6, where DEU is C5H 12 N2O.

[0041] This embodiment also includes a method for preparing the above-mentioned organic-inorganic hybrid luminescent halide material, comprising the following steps:

[0042] 0.174 g of N,N'-diethylurea and 0.187 g of TbCl3·6H2O were weighed and placed in a mortar. 0.05 mL of methanol was then dropped into the mortar and ground for 10 min to obtain a polycrystalline powder of an organic-inorganic hybrid luminescent halide material, namely, a polycrystalline powder of [Tb(DEU)6]TbCl6.

[0043] Mechanical grinding preparation process Figure 1 As shown, this material can be quickly ground and synthesized in atmospheric atmosphere at room temperature.

[0044] Example 3

[0045] An organic-inorganic hybrid luminescent halide material has a general chemical formula of [Tb(DMU)6]TbCl6, where DMU is C3H8N2O.

[0046] This embodiment also includes a method for preparing the above-mentioned organic-inorganic hybrid luminescent halide material, comprising the following steps:

[0047] (1) Weigh 0.132 g of N,N'-dimethylurea and 0.187 g of TbCl3·6H2O, add 5 mL of methanol and mix well to obtain a clear mixed solution;

[0048] (2) The mixed solution was placed in a fume hood to evaporate the methanol for 5 h, and transparent [Tb(C3H8N2O)6]TbCl6 crystals were obtained, which were recorded as [Tb(DMU)6]TbCl6 crystals.

[0049] Example 4

[0050] An organic-inorganic hybrid luminescent halide material has a general chemical formula of [Tb(DMU)6]TbCl6, where DMU is C3H8N2O.

[0051] This embodiment also includes a method for preparing the above-mentioned organic-inorganic hybrid luminescent halide material, comprising the following steps:

[0052] 0.132 g of N,N'-dimethylurea and 0.187 g of TbCl3·6H2O were weighed and placed in a mortar, and 0.05 mL of methanol was added thereto. The mixture was ground for 10 min to obtain a polycrystalline powder of an organic-inorganic hybrid luminescent halide material, namely, a polycrystalline powder of [Tb(DMU)6]TbCl6.

[0053] Example 5

[0054] An organic-inorganic hybrid luminescent halide material with the general chemical formula [Eu(DEU)6]EuCl6, where DEU is C5H 12 N2O.

[0055] This embodiment also includes a method for preparing the above-mentioned organic-inorganic hybrid luminescent halide material, comprising the following steps:

[0056] (1) Weigh 0.174 g of N,N'-diethylurea and 0.183 g of EuCl3·6H2O, add 5 mL of methanol and mix well to obtain a clear mixed solution;

[0057] (2) The mixed solution is placed in a fume hood to evaporate the methanol for 5 hours, and a transparent organic-inorganic hybrid luminescent halide material crystal is obtained, namely [Eu(DEU)6]EuCl6 crystal.

[0058] Example 6

[0059] An organic-inorganic hybrid luminescent halide material has a general chemical formula of [Eu(DMU)6]EuCl6, where DMU is C3H8N2O.

[0060] This embodiment also includes a method for preparing the above-mentioned organic-inorganic hybrid luminescent halide material, comprising the following steps:

[0061] (1) Weigh 0.132 g of N,N'-dimethylurea and 0.183 g of EuCl3·6H2O, add 5 mL of methanol and mix well to obtain a clear mixed solution;

[0062] (2) The mixed solution is placed in a fume hood to evaporate the methanol for 5 hours, and a transparent organic-inorganic hybrid luminescent halide material crystal is obtained, namely, [Eu(DMU)6]EuCl6 crystal.

[0063] Example 7

[0064] An organic-inorganic hybrid luminescent halide material with the general chemical formula [Ce(DEU)6]CeCl6, where DEU is C5H 12 N2O.

[0065] This embodiment also includes a method for preparing the above-mentioned organic-inorganic hybrid luminescent halide material, comprising the following steps:

[0066] (1) Weigh 0.174 g of N,N'-diethylurea and 0.186 g of CeCl3·6H2O, add 5 mL of methanol and mix well to obtain a clear mixed solution;

[0067] (2) The mixed solution is placed in a fume hood to evaporate the methanol for 5 hours, and a transparent organic-inorganic hybrid luminescent halide material crystal is obtained, namely, [Ce(DEU)6]CeCl6 crystal.

[0068] Example 8

[0069] An organic-inorganic hybrid luminescent halide material has a general chemical formula of [Ce(DMU)6]CeCl6, where DMU is C3H8N2O.

[0070] This embodiment also includes a method for preparing the above-mentioned organic-inorganic hybrid luminescent halide material, comprising the following steps:

[0071] (1) Weigh 0.132 g of N,N'-dimethylurea and 0.187 g of CeCl3·6H2O, add 5 mL of methanol and mix well to obtain a clear mixed solution;

[0072] (2) The mixed solution was placed in a fume hood to evaporate the methanol for 5 hours, and a transparent organic-inorganic hybrid luminescent halide material crystal was obtained, namely [Ce(DMU)6]CeCl6 crystal.

[0073] Comparative Example 1

[0074] An organic-inorganic hybrid luminescent halide material has a general chemical formula of (DMA)4TbCl7, wherein DMA is a dimethylamine cation and has a chemical formula of CH3NH2CH3.

[0075] This comparative example also includes a method for preparing the above-mentioned organic-inorganic hybrid luminescent halide material, comprising the following steps:

[0076] Weigh 0.187 g of TbCl3·6H2O and place it in a mixed solution of 5 mL of hydrochloric acid and 310 μL of N,N-dimethylformamide. Heat the mixed solution to 180°C for 5 min and then cool it to room temperature to obtain (DMA)4TbCl7 crystals.

[0077] Experimental example

[0078] 1. Bonding analysis

[0079] The electrostatic potential distribution of N,N'-dimethylurea molecules and N,N'-diethylurea molecules and the specific bonding situation of N,N'-diethylurea molecules in the [Tb(DEU)6]TbCl6 crystal of Example 1 were analyzed. The results are as follows: Figure 2 shown.

[0080] from Figure 2 As can be seen from the figure, N,N'-dimethylurea and N,N'-diethylurea are both amphiphilic molecules with positively charged ends and negatively charged ends located on the upper and lower sides of the alkane chain, which are conducive to attracting positively charged isolated Tb 3+ ions and negatively charged [TbCl6] 3- Octahedron.

[0081] 2. Material structure analysis

[0082] The crystal structures of [Tb(DEU)6]TbCl6 of Example 1 and [Tb(DMU)6]TbCl6 of Example 3 were analyzed. Figures 3 to 8 shown.

[0083] from Figures 3 and 4 It can be seen that the materials obtained in Example 1 and Example 3 are both typical zero-dimensional crystal structures, with the center Tb 3+ They are surrounded by six organic ligands (N,N'-dimethylurea molecules or N,N'-diethylurea molecules) to form a six-coordinated positive ion cage; the organic ligands also form a pair of [TbCl6] 3- The hydrophobic wrapping structure forms a shield.

[0084] From the [Tb(DEU)6]TbCl6 structure of Example 1, it is clear that the pseudo-molecular cage structure is represented by cage 1 and cage 2. Figure 5 It can be seen that cage 1 and cage 2 are both composed of six N,N'-diethylurea molecules, but the N,N'-diethylurea molecules of the two pseudo-molecular cages have different orientations.

[0085] The percentage volume (%Vbur) of [Tb(DEU)6]TbCl6 of Example 1 and [Tb(DMU)6]TbCl6 of Example 3 are as follows: Figure 6 As shown; Hirshfeld surface analysis is as follows Figure 7 and Figure 8 shown.

[0086] from Figure 6 It can be seen that [Tb(DEU)6] 3+ and [Tb(DMU)6] 3+ The volume percentages of the organic ligands were as high as 93.4% and 94.5%, respectively, indicating that the organic ligands have a great influence on the isolated Tb 3+ Ions have high coverage. Figures 7 and 8 It can be seen that both [Tb(DEU)6]TbCl6 and [Tb(DMU)6]TbCl6 systems are dominated by hydrogen bond interactions, which enhances the crystal density; at the same time, [Tb(DEU)6]TbCl6 exhibits stronger H···H interactions than [Tb(DMU)6]TbCl6.

[0087] 3. XRD diffraction analysis

[0088] XRD diffraction analysis was performed on [Tb(DEU)6]TbCl6 of Example 1, [Tb(DMU)6]TbCl6 of Example 3 and (DMA)4TbCl7 of Comparative Example 1 using an X-ray diffractometer (Rigaku D / MAX-r, CuKα radiation source (λ = 1.54184Å), relative humidity 30-40%). The results are as follows: Figure 9 shown.

[0089] By comparing the XRD patterns under different storage times (storage environment: atmospheric atmosphere with relative humidity of 55-65%), the structural stability of different materials can be evaluated. Figure 9 It can be seen that the diffraction peak position of [Tb(DEU)6]TbCl6 in Example 1 can still remain stable after storage for 3 months, indicating that it has good structural stability; the diffraction peak of [Tb(DMU)6]TbCl6 in Example 3 changes after storage for 3 days, and its structural stability is slightly worse than that of [Tb(DEU)6]TbCl6; and the spectrum line of (DMA)4TbCl7 in Comparative Example 1 shifts and fluctuates a lot after storage for 2 hours, indicating poor stability.

[0090] 4. Photoluminescence quantum yield determination

[0091] The change of the photoluminescence quantum yield (PLQY) value of [Tb(DEU)6]TbCl6 in Example 1 was measured using a fluorescence spectrometer (Edinburgh FS-5, relative humidity 30-40%). The results are as follows: Figure 10 shown.

[0092] from Figure 10 It can be seen that [Tb(DEU)6]TbCl6 in Example 1 can stably exist for up to 3 months in an atmospheric atmosphere with a relative humidity of 55-65%, and has good air stability, which solves the problem that traditional lanthanide-based organic-inorganic hybrid luminescent halide materials cannot exist stably in the atmospheric environment.

[0093] The present invention has been described according to the above embodiments. It should be understood that the above embodiments do not limit the present invention in any form. Any technical solutions obtained by equivalent replacement or equivalent transformation fall within the scope of the present invention.

Claims

1. A method for preparing an organic-inorganic hybrid luminescent halide material, characterized in that: L and compound ACl3·xH2O were used as raw materials and prepared by solution evaporation method; The solution volatilization method comprises the following steps: L and compound ACl3·xH2O are used as raw materials, a solvent is added and mixed, and then the mixture is allowed to stand for the solvent to evaporate, thereby obtaining a crystal of an organic-inorganic hybrid luminescent halide material; The chemical formula of the organic-inorganic hybrid luminescent halide material is AL6ACl6, wherein A is a lanthanide ion, L is N,N'-diethylurea; the lanthanide ion is Tb 3+ ; The organic-inorganic hybrid luminescent halide material has a pseudo-molecular cage structure.

2. The method for preparing the organic-inorganic hybrid luminescent halide material according to claim 1, wherein: The compound ACl3·xH2O is TbCl3·6H2O.

3. The method for preparing the organic-inorganic hybrid luminescent halide material according to claim 1, wherein: The molar ratio of ACl3·xH2O and L is 1:3; the solvent is methanol, ethanol or acetone; the ratio of the solvent volume to the total mass of ACl3·xH2O and L is 10~20mL:1g.

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