Preparation and application of undoped or ion-doped all-inorganic non-lead two-center metal halide materials

Abstract

The application discloses undoped and ion-doped all-inorganic non-lead double-center metal halide materials and preparation and application thereof. The all-inorganic non-lead double-center metal halide materials are synthesized by a solution method in one step, stirring and mixing, and temperature reduction and crystallization, and finally colorless flaky transparent crystals are obtained, and the structural composition of the crystals is A5BB'X8:M, wherein A is an alkali metal ion, B is a divalent metal cation, B' is a monovalent metal cation, X is a halogen ion, A and B' cannot be the same, and M is a doping ion. The preparation method is simple, the metal halide crystal material obtained is environment-friendly, non-toxic, stable, and has high-efficiency visible light wide-spectrum luminescence performance, and has great development potential in the fields of illumination, display, photoelectric detection, solar cells, lasers, sensors, photoelectric catalysis and the like. The application solves the toxicity problem of lead-based perovskite, improves the stability of the new all-inorganic non-lead double-center metal halide through doping, and simultaneously improves the fluorescence performance, and has good application prospect in various fields.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of inorganic solid materials, and particularly relates to synthesis and application scenarios of a novel photoelectric material. BACKGROUND

[0002] Lead-based halide perovskite materials have good photoelectric properties and have been used to prepare light-emitting diodes, solar cells, photoelectric detectors and other devices. However, their toxicity and instability seriously restrict their large-scale application. All-inorganic non-lead metal halides have great potential in the fields of solar cells, photoelectric detection, photocatalysis, light-emitting display and the like due to their non-toxic and environmentally friendly properties, excellent photoelectric performance and good stability, and have been widely studied in recent years.

[0003] Therefore, in order to be environmentally friendly and sustainable, it is an inevitable trend for metal halide materials to replace lead with non-toxic or low-toxic non-lead elements. In non-lead metal halides, the following problems are faced: the excitation light range is in a deep ultraviolet band, resulting in a high turn-on voltage value required for LED devices; as an emission layer, the emission spectrum peak is narrow, making it difficult to achieve wide-band white light emission with a single material. At the same time, due to the limitation of its structure, non-lead metal halides have few achievements in the fields of photoelectric detection, photoelectric catalysis and encryption storage. Therefore, designing and developing a material with a new structure, low energy excitation, suitable band gap and novel structure is the key to achieving major breakthroughs in various fields of metal halide materials, thereby realizing large-scale commercial application. SUMMARY

[0004] The present application aims to provide an undoped and ion-doped all-inorganic non-lead double-center metal halide material and a preparation method thereof. The material can be prepared as a single crystal, microcrystal, nanocrystal, powder and thin film, etc. The material is simple to prepare, environmentally friendly and non-toxic, has excellent photoelectric performance, and is expected to be used in photoelectric devices, lighting, lasers, solar cells, sensors and as a catalyst.

[0005] The present application successfully obtains an undoped or ion-doped all-inorganic non-lead double-center metal halide material by adjusting the relative content of A + , B 2+ , B’ + The undoped all-inorganic non-lead double-center metal halide material has a chemical formula of A5BB’X8, wherein A is one or more of Cs + , Rb + , K + , Na + and the like, B is one or more of Zn 2+ , Mn 2+ and the like, and B’ is one or more of Cu + , Ag + , K+ Na + X is one or more of the monovalent metal cations, X is one or more of the halide ions such as Cl, Br, and I, and A and B' cannot be the same;

[0006] The ion-doped all-inorganic lead-free dual-center metal halide material has the chemical formula A5BB'X8:M, where A is Cs. + 、Rb + K + Na + One or more of the following metal cations, where B is Zn 2+ Mn 2+ Cd 2+ One or more of the divalent metal cations, where B' is Cu + Ag + K + Na + The cations are monovalent metal cations, where X is one or more of the halide ions, A and B' cannot be the same, and M is a dopant ion, which is one or more of the transition metal ions and rare earth ions of elements such as Mn, Bi, Sb, and In.

[0007] The material has a symmetrical tetragonal crystal structure, wherein B 2+ and B' + Layered and staggered, occupying different sites, B 2+ With X - The structural unit is [BX6]. 4- , with B 2+ Centered on X - The ligands have a six-coordinate octahedral structure, with the octahedra connected by a common vertex X. - They extend and connect sequentially along the horizontal plane to form a 2D planar layer, B' + With X - The structural unit is [B'X4]. 3- , with B' + Centered on X - The ligands have a tetrahedral structure with independent tetrahedra, forming an 0D structure. The 2D planar layer is separated from the 0D structure by A. + Completely separated, forming a sandwich structure with 2D planar layers and 0D structures interspersed.

[0008] The doped ion M replaces the position of the B ion or B' ion, or is located in the interstitial space of the crystal lattice;

[0009] The doping amount of M ions is greater than 0% and less than 80% relative to B or B', preferably greater than 0% and less than 50%.

[0010] The preparation method of the undoped all-inorganic non-lead double-center metal halide material is performed according to the following steps:

[0011] (1) one or more of the salt or oxide of metal A, one or more of the salt or oxide of metal B, and one or more of the salt or oxide of metal B' are added into a mixed solution of hydrohalic acid (HX) and hypophosphorous acid (H2PO2), and heating and stirring are performed until the raw materials are completely dissolved in an air environment to obtain a solution;

[0012] The salt of metal A is one or more of a halide metal salt (AX), an acetate salt (CH3COOA), and a carbonate salt (A2CO3), and the oxide is an alkali metal oxide (A2O);

[0013] The salt of metal B is one or more of a halide metal salt (BX2), an acetate salt ((CH3COO)2B), and a carbonate salt (BCO3), and the oxide is BO;

[0014] The salt of metal B' is one or more of a halide metal salt (B'X), an acetate salt ((CH3COO)B'), and a carbonate salt (B'2CO3), and the oxide is B'2O;

[0015] (2) after the reaction is completed, the solution obtained in step (1) is cooled to room temperature, and the product is crystallized and separated out from the solution during the cooling process to obtain flaky crystals; then solid-liquid separation (preferably suction filtration) is performed, and the obtained product is dried to obtain the final A5BB'X8 material.

[0016] The preparation method of the ion-doped all-inorganic non-lead double-center metal halide material is performed according to the following steps:

[0017] (1) one or more of the salt or oxide of metal A, one or more of the salt or oxide of metal B, one or more of the salt or oxide of metal B', and one or more of the salt or oxide of the doping metal M are added into a mixed solution of hydrohalic acid (HX) and hypophosphorous acid (H2PO2) in an air environment, and heating and stirring are performed until the raw materials are completely dissolved to obtain a solution;

[0018] The salt of metal A is one or more of a halide metal salt (AX), an acetate salt (CH3COOA), or a carbonate salt (A2CO3), and the oxide is an alkali metal oxide (A2O);

[0019] The salt of metal B is one or more of a halide metal salt (BX2), an acetate salt ((CH3COO)2B), and a carbonate salt (BCO3), and the oxide is BO;

[0020] The metal B' salt is one or more of halide metal salt (B'X), acetate salt ((CH3COO)B') and carbonate salt (B'2CO3), and the oxide is B'2O;

[0021] The doped metal M salt is one or more of halide metal salt (MXz), acetate salt ((CH3COO) z M) and carbonate salt (M 2 / z CO3) (wherein z is a positive integer and 1≤z≤4); 2 / z

[0022] (2) After the reaction is completed, the solution obtained in step (1) is cooled to room temperature, and the product is crystallized out of the solution during the cooling process to obtain flaky crystals; then, filtration is performed, and the obtained product is dried to obtain the final A5BB'X8:M material.

[0023] The method for synthesizing the material, characterized in that:

[0024] In step (1), the molar ratio of A:B:B' in the salt or oxide of metal A, the salt or oxide of metal B, and the salt or oxide of metal B' is 1-5:1:1, preferably 2:1:1; the molar ratio of A:B:B':M in the salt or oxide of metal A, the salt or oxide of metal B, the salt or oxide of metal B', and the doped metal M salt or oxide is 1-5:1:1:0-0.8, preferably 2:1:1:0.5;

[0025] In step (1), the hydrohalic acid is a 48wt.% hydrohalic acid aqueous solution, 2-5 mL of the hypophosphorous acid is used per mmol of the salt or oxide of metal B, and the volume ratio of the two is 5-15:1, preferably 9-11:1;

[0026] In step (1), the heating temperature is 80-120°C, preferably 90-110°C, and most preferably 100°C; and the heating time is 30-100 minutes, preferably 50-70 minutes;

[0027] In step (2), the cooling rate is a certain cooling rate that can control the size of the crystal growth size within a certain range, and the cooling rate is preferably 5°C / hour;

[0028] In step (2), the vacuum drying temperature is 60-80°C, preferably 65-75°C; and the drying time is 12-24 hours, preferably 20-24 hours.

[0029] ​The A5BB'X8 material structure is characterized and verified by single crystal X-ray diffraction (SCXRD) and powder X-ray diffraction (PXRD), respectively, and the experimental process is as follows:

[0030] The single crystal X-ray diffractometer is used to test the crystal structure of the material. 2+ And B' + The layers occupy different sites, B 2+ And X - Form a structural unit

BX6

B'X4

[0031] The powder X-ray diffractometer is used to test and analyze the material phase, and the material has an XRD diffraction pattern as shown in Figure 2 .

[0032] The A5BB'X8:Mn material emits green light at room temperature and emits white light with multiple peaks at low temperature, and the human eye is sensitive to green light and white light, so it can be used as a direct visual temperature sensor. The fluorescence spectrum is characterized, and the experimental process is as follows:

[0033] The fluorescence spectrometer (Edinburgh FLS1000, England) is used to collect the fluorescence emission spectrum under 290nm ultraviolet light excitation, which shows green light; the fluorescence excitation spectrum is tested under the 520nm emission peak, and the excitation and emission spectra as shown in Figure 3 can be obtained, the material can be excited in the range of 240nm-370nm, the emission peak is located at 520nm in the excitable range, and the multi-peak emission is realized at low temperature, the light emission range penetrates the entire visible light region (400-800nm), and bright white light is exhibited.

[0034] The physical and chemical properties of A5BB'X8 and A5BB'X8:M materials are stable.

[0035] The application also provides the application of the above-mentioned A5BB'X8 and A5BB'X8:M materials in the fields of lighting, display, etc., which can be applied to the emission layer of a light emitting diode.

[0036] The application also provides a photoelectric device containing the above-mentioned A5BB'X8 and A5BB'X8:M materials, such as a photoelectric detector, an X-ray detector, etc.

[0037] The application also provides a sensor containing the A5BB'X8 and A5BB'X8:M materials, such as a visual temperature sensor / humidity / water sensor, etc.

[0038] The application also provides an application of the A5BB'X8 and A5BB'X8:M materials in the catalysis field, such as a photocatalysis, electrocatalysis field as a catalyst.

[0039] The beneficial effects of the application are as follows:

[0040] The application prepares a new environment-friendly undoped and ion-doped all-inorganic non-lead double-center metal halide A5BB'X8 and A5BB'X8:M material, the obtained product has adjustable size, high stability and excellent luminescent performance, the material can realize multi-size preparation from single crystal, microcrystal, nanocrystal, powder and thin film; meanwhile, the preparation method of the material is simple, convenient and has good reproducibility, which is conducive to large-scale industrialized preparation. The application has the advantages of novel material structure and high luminescent performance, and can be applied in the fields of luminescent lighting, display, etc., and has great development potential and commercialization prospect in the fields of laser, temperature / humidity / water sensing, photocatalysis or photoelectric catalysis, photoelectric detector and solar cell.

[0041] In order to better understand and implement, the application is described in detail below in combination with the drawings and specific preferred examples. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 A unit cell structure diagram obtained by XRD analysis of an undoped all-inorganic non-lead double-center metal halide Rb5ZnCuBr8 single crystal;

[0043] Figure 2 A comparison diagram of powder XRD spectra and single crystal simulation XRD spectra of the undoped and manganese-doped all-inorganic non-lead double-center metal halide single crystal materials Rb5ZnCuBr8 and Rb5ZnCuBr8:Mn in the example;

[0044] Figure 3 An ultraviolet-visible absorption spectrum and a room temperature steady-state fluorescence spectrum of the manganese-doped all-inorganic non-lead double-center metal halide single crystal material Rb5ZnCuBr8:Mn;

[0045] Figure 4 A low-temperature steady-state fluorescence spectrum of the manganese-doped all-inorganic non-lead double-center metal halide single crystal material Rb5ZnCuBr8:Mn. DETAILED DESCRIPTION

[0046] The application is further described below in combination with the drawings and specific implementation examples:

[0047] Example 1

[0048] Weigh 0.3307 g (2 mmol) of rubidium bromide, 0.1434 g (1 mmol) of cuprous bromide, and 0.2140 g (1 mmol) of zinc bromide into a 20 mL glass vial containing 5 mL of hydrobromic acid (48 wt.%) as solvent and 0.5 mL of hypophosphoric acid (50 wt.%) to prevent oxidation of cuprous ions. Place the vial in an oil bath on a heating plate (equipped with a temperature sensor or thermocouple for temperature monitoring) and heat and stir at 100 °C for 1 h. After the reaction is complete, turn off the stirring unit and cool to room temperature at a rate of 5 °C per hour. Filter quickly and place the resulting crystals in a vacuum drying oven at 70 °C for 24 h to obtain colorless, transparent, flaky crystals, which is Rb5ZnCuBr8 material.

[0049] like Figure 1 The figure shows the cell structure obtained by single-crystal XRD analysis of Rb5ZnCuBr8 material. The chemical formula of the material was confirmed as Rb5ZnCuBr8 using a Bruker APEX-II CCD diffractometer and the ShelXT method (the instrument and method used in the following examples). Its structure is a sandwich structure with alternating 2D planar layers and 0D structures, belonging to the tetragonal crystal system.

[0050] like Figure 2 The image shows a comparison between the powder XRD pattern and the simulated XRD pattern of the Rb5ZnCuBr8 material. The powder XRD pattern could not be matched with a suitable inorganic phase in the ICDD-PDF-4+ database, indicating a novel inorganic material that has not been previously discovered. Furthermore, the XRD diffraction peaks correspond well with those simulated by the single-crystal XRD pattern, confirming the correctness of the unit cell structure. In addition, the high intensity and narrow peak width of each diffraction peak in the XRD pattern indicate that the prepared Rb5ZnCuBr8 material has high crystallinity.

[0051] Example 2

[0052] Take 0.462 g (2 mmol) of rubidium carbonate, 0.187 g (1 mmol) of cuprous carbonate, 0.125 g (1 mmol) of zinc carbonate into a 20 mL glass vial containing 5 mL of hydrobromic acid (48 wt. %) as a solvent and to provide halogen ions and 0.5 mL of hypophosphorous acid (50 wt. %) to prevent oxidation of cuprous ions. Put it into an oil bath on a heating plate (which is equipped with a temperature sensor or thermocouple to monitor the temperature), heat and stir at 100 ℃ for 1 h. After the reaction is completed, turn off the stirring unit, cool to room temperature at a rate of 5 ℃ per hour, quickly filter, and put the obtained crystals into a vacuum drying oven at 70 ℃ for 24 h to obtain colorless transparent flaky crystal material. The chemical formula of the material is confirmed to be Rb5ZnCuBr8, which has a sandwich structure of 2D planar layers and 0D structures staggered, and belongs to the tetragonal system. Compared with Example 1, it shows that the hydrohalic acid has a dual role, which can not only act as a solvent, but also act as a halogen source when halogen is deficient.

[0053] Example 3

[0054] Take 0.2730 g (2 mmol) of rubidium acetate, 0.1145 g (1 mmol) of cuprous acetate, 0.232 g (1 mmol) of zinc acetate into a 20 mL glass vial containing 5 mL of hydrobromic acid (48 wt. %) as a solvent and to provide halogen ions and 0.5 mL of hypophosphorous acid (50 wt. %) to prevent oxidation of cuprous ions. Put it into an oil bath on a heating plate (which is equipped with a temperature sensor or thermocouple to monitor the temperature), heat and stir at 100 ℃ for 1 h. After the reaction is completed, turn off the stirring unit, cool to room temperature at a rate of 5 ℃ per hour, quickly filter, and put the obtained crystals into a vacuum drying oven at 70 ℃ for 24 h to obtain colorless transparent flaky crystal material. The chemical formula of the material is confirmed to be Rb5ZnCuBr8, which has a sandwich structure of 2D planar layers and 0D structures staggered, and belongs to the tetragonal system. Compared with Example 1, it shows that the hydrohalic acid has a dual role, which can not only act as a solvent, but also act as a halogen source when halogen is deficient.

[0055] Example 4

[0056] Take 0.1710 g (1 mmol) of rubidium oxide, 0.0715 g (0.5 mmol) of cuprous oxide, 0.0810 g (1 mmol) of zinc oxide into a 20 mL glass vial containing 5 mL of hydrobromic acid (48 wt. %) as a solvent to provide halogen and 0.5 mL of hypophosphorous acid (50 wt. %) to prevent oxidation of cuprous ions. Put it into an oil bath on a heating plate (with a temperature sensor or thermocouple to monitor the temperature), heat and stir at 100 ℃ for 1 h. After the reaction is completed, turn off the stirring unit, cool to room temperature at a rate of 5 ℃ per hour, quickly filter, and put the obtained crystals into a vacuum drying oven at 70 ℃ for 24 h to obtain colorless transparent flaky crystal material. The chemical formula of the material is confirmed to be Rb5ZnCuBr8, which has a sandwich structure with 2D planar layers and 0D structures staggered, and belongs to the tetragonal system. Compared with Example 1, it shows that the hydrohalic acid has a dual role, which can not only act as a solvent, but also as a halogen source when halogen is scarce.

[0057] Example 5

[0058] Take 0.3307 g (2 mmol) of rubidium bromide, 0.1878 g (1 mmol) of silver bromide, and 0.2140 g (1 mmol) of zinc bromide into a 20 mL glass vial containing 5 mL of hydrobromic acid (48 wt. %) as a solvent. Put it into an oil bath on a heating plate (with a temperature sensor or thermocouple to monitor the temperature), heat and stir at 100 ℃ for 1 h. After the reaction is completed, turn off the stirring unit, cool to room temperature at a rate of 5 ℃ per hour, quickly filter, and put the obtained crystals into a vacuum drying oven at 70 ℃ for 24 h to obtain colorless transparent flaky crystal Rb5ZnAgBr8 material. The obtained material is analyzed by single crystal XRD to obtain a unit cell structure diagram, and the chemical formula of the material is confirmed to be Rb5ZnAgBr8, which has a sandwich structure with 2D planar layers and 0D structures staggered, and belongs to the tetragonal system. Compared with Example 1, it shows that after replacing B', the original structure can still be maintained. At the same time, Ag + It is not easy to be oxidized in air, so it is not necessary to add hypophosphorous acid during the experiment, which proves that hypophosphorous acid only plays a role in preventing oxidation in the experiment.

[0059] Example 6

[0060] 0.3307 g (2 mmol) of rubidium bromide, 0.2132 g (1 mmol) of cesium bromide, and 0.2140 g (1 mmol) of zinc bromide were weighed and added to a 20 mL glass vial containing 5 mL of hydrobromic acid (48 wt.%) as solvent. The vial was placed in an oil bath on a heating plate (equipped with a temperature sensor or thermocouple for temperature monitoring) and heated and stirred at 100 °C for 1 h. After the reaction was complete, the stirring unit was turned off, and the temperature was lowered to room temperature at a rate of 5 °C per hour. The mixture was then rapidly filtered, and the resulting crystals were dried in a vacuum drying oven at 70 °C for 24 h. Unlike the expected colorless, transparent, flaky crystals of Rb5ZnCsBr8, the obtained material, obtained by single-crystal XRD analysis, showed a crystal structure diagram, proving that it was a mixture of Rb2ZnBr4 and Cs2ZnBr4, with a significantly different crystal structure. This demonstrates the necessity that A and B' cannot be the same.

[0061] Example 7

[0062] Weigh 0.3307 g (2 mmol) of rubidium bromide, 0.1434 g (1 mmol) of cuprous bromide, 0.2140 g (1 mmol) of zinc bromide, and 0.1072 g (0.5 mol) of manganese bromide into a 20 mL glass vial containing 5 mL of hydrobromic acid (48 wt.%) and 0.5 mL of hypophosphoric acid (50 wt.%). Place the vial in an oil bath on a heating plate (temperature monitored by a temperature sensor or thermocouple) and heat and stir at 100 °C for 1 h. After the reaction is complete, turn off the stirring unit and cool to room temperature at a rate of 5 °C per hour. Filter quickly and place the resulting crystals in a vacuum drying oven at 70 °C for 24 h to obtain colorless, transparent, flaky crystals, which is Rb5ZnCuBr8:Mn material.

[0063] Powder XRD diffraction test results, such as Figure 2 As shown, the obtained novel manganese-doped all-inorganic lead-free dual-center metal halide material corresponds well with the XRD diffraction peaks simulated by single-crystal XRD, confirming the correctness of the unit cell structure. Its structure is a sandwich structure with alternating 2D planar layers and 0D structures, belonging to the tetragonal crystal system. Furthermore, the high intensity and narrow peak width of each diffraction peak in the XRD pattern indicate that the prepared Rb5ZnCuBr8:Mn material has high crystallinity.

[0064] Example 8

[0065] A 20 mL glass vial was charged with 0.3307 g (2 mmol) of rubidium bromide, 0.1434 g (1 mmol) of cuprous bromide, 0.2140 g (1 mmol) of zinc bromide, 0.2245 g (0.5 mol) of bismuth bromide, 5 mL of hydrobromic acid (48 wt.%), and 0.5 mL of hypophosphorous acid (50 wt.%). It was placed in an oil bath on a hot plate (temperature sensor or thermocouple to monitor temperature) and heated at 100 °C for 1 h with stirring. After the reaction was complete, the stirring unit was turned off and allowed to cool to room temperature at a rate of 5 °C per hour. The resulting crystals were quickly filtered and placed in a vacuum oven at 70 °C for 24 h to dry. Colorless transparent plate-like crystals were obtained. The unit cell structure of the obtained material was determined by single crystal XRD analysis, confirming that the chemical formula of the material was Rb5ZnCuBr8:Bi. The structure of the material was a sandwich structure with 2D planar layers and 0D structures staggered and distributed, belonging to the tetragonal system. The XRD of the material was consistent with Example 4, proving the diversity of doping ions M.

[0066] Example 9

[0067] A 20 mL glass vial was charged with 0.3307 g (2 mmol) of rubidium bromide, 0.1434 g (1 mmol) of cuprous bromide, 0.2140 g (1 mmol) of zinc bromide, 0.2245 g (0.5 mol) of bismuth bromide, 5 mL of hydrobromic acid (48 wt.%), and 0.5 mL of hypophosphorous acid (50 wt.%). It was placed in an oil bath on a hot plate (temperature sensor or thermocouple to monitor temperature) and heated at 100 °C for 1 h with stirring. After the reaction was complete, the stirring unit was turned off and allowed to cool to room temperature at a rate of 5 °C per hour. The resulting crystals were quickly filtered and placed in a vacuum oven at 70 °C for 24 h to dry. Colorless transparent plate-like crystals were obtained. The unit cell structure of the obtained material was determined by single crystal XRD analysis, confirming that the chemical formula of the material was Rb5ZnCuBr8:Bi. The structure of the material was a sandwich structure with 2D planar layers and 0D structures staggered and distributed, belonging to the tetragonal system. The XRD of the material was consistent with Example 4, proving the diversity of doping ions M.

[0068] Example 10

[0069] Take 0.3307 g (2 mmol) of rubidium bromide, 0.1434 g (1 mmol) of cuprous bromide, 0.2140 g (1 mmol) of zinc bromide into a 20 mL glass vial containing 5 mL of hydrobromic acid (48 wt.% mass concentration) as solvent and 0.5 mL of hypophosphorous acid (50 wt.% mass concentration) to prevent oxidation of cuprous ions. Put it into the oil bath on the heating plate (where the temperature sensor or thermocouple monitors the temperature), heat and stir at 100°C for 1 h. After the reaction is completed, turn off the stirring unit, cool to room temperature naturally, quickly filter, and put the obtained powder into a vacuum drying oven at 70°C for 24 h to obtain the Rb5ZnCuBr8 material. Compared with the crystal obtained in Example 1, the crystallinity of the powder is not good, and it is more prone to blackening and decomposition.

[0070] Example 11

[0071] Take 0.2381 g (2 mmol) of potassium bromide, 0.1434 g (1 mmol) of cuprous bromide, 0.2724 g (1 mmol) of cadmium bromide into a 20 mL glass vial containing 5 mL of hydrobromic acid (48 wt.% mass concentration) as solvent and 0.5 mL of hypophosphorous acid (50 wt.% mass concentration) to prevent oxidation of cuprous ions. Put it into the oil bath on the heating plate (where the temperature sensor or thermocouple monitors the temperature), heat and stir at 100°C for 1 h. After the reaction is completed, turn off the stirring unit, and cool to room temperature at a rate of 5°C per hour, quickly filter, and put the obtained crystal into a vacuum drying oven at 70°C for 24 h to obtain colorless transparent flaky crystals. The obtained material is analyzed by single crystal XRD to obtain the unit cell structure diagram, confirming that the chemical formula of the material is K5CdCuBr8, and by analysis, the structure is a sandwich structure with 2D planar layers and 0D structures staggered, and the material belongs to the tetragonal system.

[0072] Example 12

[0073] A 20 mL glass vial was charged with 0.2381 g (2 mmol) of potassium bromide, 0.1434 g (1 mmol) of cuprous bromide, 0.2724 g (1 mmol) of cadmium bromide and 1.1774 g (0.5 mmol) of indium bromide as solvent with 5 mL of hydrobromic acid (48 wt.% concentration) and 0.5 mL of hypophosphorous acid (50 wt.% concentration) to prevent oxidation of cuprous ions. It was placed in an oil bath on a heating plate (with a temperature sensor or thermocouple to monitor the temperature) and heated at 100 °C for 1 h with stirring. After the reaction was completed, the stirring unit was turned off, and it was cooled to room temperature at a rate of 5 °C per hour. The resulting crystals were quickly filtered and placed in a vacuum drying oven at 70 °C for 24 h to obtain colorless transparent flaky crystals. The obtained material was analyzed by single crystal XRD to obtain a crystal cell structure diagram, which confirmed that the chemical formula of the material was K5CdCuBr8:In, and by analysis, the structure was a sandwich structure with 2D planar layers and 0D structures staggered, and the material belonged to the tetragonal system.

[0074] Example 13

[0075] The materials synthesized in Examples 1-5, 7-9, 11-12 were stable for more than 1 month at 25 °C, 55% relative humidity and 0.6 sun (36,000 lx) illumination, indicating that the stability of these materials was excellent.

[0076] Example 14

[0077] The application of the new all-inorganic non-lead double-center metal halide material as a visual temperature detector used the Rb5ZnCuBr8:Mn material prepared in Example 7 as a raw material, which was mixed with an appropriate amount of PMMA, and the obtained colloid was spin-coated on a silicon wafer substrate to prepare a photoluminescent LED. Using a fluorescence spectrometer (Edinburgh FLS1000, England), the fluorescence emission spectrum was collected under 290 nm ultraviolet light excitation, which exhibited green light. The fluorescence excitation spectrum was tested under the 520 nm emission peak, and the excitation and emission spectra were obtained as shown in FIG. 6. Figure 3 The material can be excited in the range of 240 nm-370 nm, and the emission peak is located at 520 nm in the excitable range. Multi-peak emission is achieved at low temperatures, and the light emission range penetrates the entire visible light region (400-800 nm), exhibiting bright white light.

[0078] The above-described examples are only preferred schemes of the present application, which are used to illustrate the present application and not to limit the scope of the present application. Any technical scheme obtained by equivalent substitution or equivalent transformation falls within the protection scope of the present application.

Claims

1. Undoped or ion-doped all-inorganic non-lead double-center metal halide material, characterized in that, The undoped all-inorganic non-lead double-center metal halide material has a chemical formula of A5BB'X8, wherein A is Cs + , Rb + , K + , Na + , one or more of metal cations, B is Zn 2+ , Mn 2+ , Cd 2+ , one or more of divalent metal cations, B' is Cu + , Ag + , K + , Na + , one or more of monovalent metal cations, and X is one or more of halogen ions, and A and B' cannot be the same. Ion-doped all-inorganic non-lead double-center metal halide material has a chemical formula of A5BB'X8:M, wherein A is Cs + , Rb + , K + , Na + one or more of metal cations, B is Zn 2+ , Mn 2+ , Cd 2+ one or more of divalent metal cations, B' is Cu + , Ag + , K + , Na + one or more of monovalent metal cations, X is one or more of halogen ions, A and B' cannot be the same, and M is a doping ion, which is a transition metal ion of Mn element.

2. The material of claim 1, wherein, The material is a symmetrical tetragonal structure, wherein B 2+ and B’ + are arranged in different positions, B 2+ and X - form a structural unit BX6 4- , a six-coordinated octahedral structure with B 2+ at the center and X - as ligands, the octahedrons are arranged in sequence along the horizontal direction and connected by sharing vertices X - , forming a 2D plane layer, B’ + and X - form a structural unit B’X4 3- , a four-coordinated tetrahedral structure with B’ + at the center and X - as ligands, the tetrahedrons are independent of each other, forming a 0D structure, the 2D plane layer and the 0D structure are completely separated by A + , forming a sandwich structure with the 2D plane layer and the 0D structure arranged alternately.

3. The material according to claim 1, characterized in that, The doping ion M replaces the position of B ion or B' ion, or is in the interstitial of the crystal lattice; The doping amount of M ion is greater than 0% and less than 80% relative to B or B'.

4. The material according to claim 3, characterized in that, The doping amount of M ion is greater than 0% and less than 50% relative to B or B'.

5. A preparation method of the undoped all-inorganic non-lead double-center metal halide material according to claim 1 or 2, which is carried out according to the following steps: (1) one or more of the salt or oxide of metal A, one or more of the salt or oxide of metal B, one or more of the salt or oxide of metal B', are added into a mixed solution of hydrohalic acid and hypophosphorous acid, heated and stirred under air environment until the raw materials are completely dissolved to obtain a solution; The salt of metal A is one or more of halide metal salt, acetate and carbonate, and the oxide is alkali metal oxide; The salt of metal B is one or more of halide metal salt, acetate and carbonate, and the oxide is BO; The salt of metal B' is one or more of halide metal salt, acetate and carbonate, and the oxide is B'2O; (2) After the reaction is completed, the solution obtained in step (1) is cooled to room temperature, and the product is crystallized and separated out from the solution during the cooling process to obtain flaky crystals; then solid-liquid separation is carried out, and the obtained product is dried to obtain the final A5BB'X8 material.

6. A preparation method of the ion-doped all-inorganic non-lead double-center metal halide material according to claim 1 or 2, which is carried out according to the following steps: (1) one or more of the salt or oxide of metal A, one or more of the salt or oxide of metal B, one or more of the salt or oxide of metal B', one or more of the salt or oxide of doping metal M, are added into a mixed solution of hydrohalic acid and hypophosphorous acid, heated and stirred under air environment until the raw materials are completely dissolved to obtain a solution; The salt of metal A is one or more of halide metal salt, acetate or carbonate, and the oxide is alkali metal oxide; The salt of metal B is one or more of halide metal salt, acetate and carbonate, and the oxide is BO; The salt of metal B' is one or more of halide metal salt, acetate and carbonate, and the oxide is B'2O; The salt of doping metal M is one or more of halide metal salt, acetate and carbonate; (2) After the reaction is completed, the solution obtained in step (1) is cooled to room temperature, and the product is crystallized and separated out from the solution during the cooling process to obtain flaky crystals; then solid-liquid separation is carried out, and the obtained product is dried to obtain the final A5BB'X8:M material.

7. The preparation method of the material according to claim 5 or 6, characterized in that: In step (1), the molar ratio of A:B:B' in the salt or oxide of metal A, the salt or oxide of metal B, the salt or oxide of metal B' is 1-5:1:1; the molar ratio of A:B:B':M in the salt or oxide of metal A, the salt or oxide of metal B, the salt or oxide of metal B', the salt or oxide of doping metal M is 1-5:1:1:0-0.8; In step (1), the hydrogen halide acid is a 48wt.% hydrogen halide acid aqueous solution, 2-5 mL of the hydrogen halide acid aqueous solution is used per mmol of the salt or oxide of metal B, the hypophosphorous acid is a 50wt.% hypophosphorous acid aqueous solution, and the volume ratio of the two is 5-15:1; In step (1), the heating temperature is 80-120℃; the heating time is 30-100 minutes; In step (2), the cooling rate is 5℃ / hour; In step (2), the drying temperature is 60-80℃; the drying time is 12-24 hours.

8. The material preparation method according to claim 7, characterized in that: In step (1), the hydrogen halide acid is a 48wt.% hydrogen halide acid aqueous solution, 2-5 mL of the hydrogen halide acid aqueous solution is used per mmol of the salt or oxide of metal B, the hypophosphorous acid is a 50wt.% hypophosphorous acid aqueous solution, and the volume ratio of the two is 9-11:1; In step (1), the heating temperature is 90-110℃; the heating time is 50-70 minutes; In step (2), the drying temperature is 65-75℃; the drying time is 20-24 hours.

9. The material according to claim 1 or 2 is applied in the field of lighting and display, and is applied to the emitting layer of a light emitting diode.

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