Wide-band excited near-infrared light-emitting metal halide with red light excitation response and preparation method and application thereof

Abstract

The invention relates to a wide-band excited near-infrared light-emitting metal halide with red light excitation response as well as preparation and application of the wide-band excited near-infrared light-emitting metal halide. The chemical composition formula of the metal halide is Rb < 2-x > CsxHf < 1-y > MoyCl6, and x is greater than or equal to 0 and less than or equal to 2; 0 < y < = 1. The emission spectrum of the near-infrared metal halide is 800-1400 nm, and the central wavelength of an emission peak is about 925 nm; an excitation peak covers a red light area, and the quantum dot has excellent wide-band excitation response capability and relatively high quantum yield. The preparation method is simple in process, large-scale preparation and technical popularization are easy to realize, and the preparation method is of great significance to development of efficient near-infrared fluorescent powder with wide-band excitation response. The near-infrared photoelectric device prepared from the metal halide shows potential application prospects in the fields of near-infrared night vision, biological imaging and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of near-infrared light-emitting materials, in particular to a near-infrared light-emitting metal halide with red light excitation response and wide-band excitation and a preparation method thereof and application of the metal halide in a near-infrared light source display device. BACKGROUND

[0002] A near-infrared light source has the characteristics of low loss and strong penetration, especially the near-infrared light with a light-emitting band of 700-1100 nm, which has a high coincidence with the characteristic absorption peak of organic functional groups (C-H, O-H and N-H), and has been widely used in medical diagnosis, night vision and food analysis in recent years. At present, the research on lead-free near-infrared light-emitting metal halides mainly focuses on two systems: one is narrow-band near-infrared light emission based on the characteristic 4f-4f transition of rare earth ions; the other is wide-band near-infrared light emission generated when trivalent chromium ions (Cr 3+ ) occupy six coordination positions in a weak octahedral crystal field. However, there are still some problems such as low quantum efficiency (usually less than 50%) and significant thermal quenching effect at high temperature, which seriously limit its practical application. Therefore, developing new near-infrared light-emitting materials has become one of the current research hotspots.

[0003] In recent years, zero-dimensional metal halides have become an important research direction in the field of light-emitting materials due to their structural designability and light-emitting wavelength tunability, and have shown broad application potential in the field of near-infrared light emission. However, the number of zero-dimensional metal halides with wide-band near-infrared emission reported at present is limited. The existing materials usually need high-energy photons such as ultraviolet light or blue light for excitation, and are accompanied by a large Stokes shift, resulting in significant energy loss and generally low light-emitting efficiency. In addition, compared with blue or red chips, ultraviolet chips have high cost and poor stability. Therefore, exploring near-infrared light-emitting materials with wide-band excitation response characteristics (i.e. can be effectively excited by longer wavelength visible light) has important research value and practical significance for promoting the practical application of near-infrared light sources. SUMMARY

[0004] In view of the deficiencies of the prior art, one of the purposes of the present application is to provide a near-infrared light-emitting metal halide with red light excitation response and wide-band excitation response. The synthesis method of the material is simple, and the prepared material has high photoluminescence quantum yield. The excitation peak covers the red light region, and the emission peak covers the near-infrared light region, which solves the key problem of the lack of low-energy light-excited zero-dimensional metal halide near-infrared light materials at present.

[0005] The second purpose of the present application is to provide a preparation method of a near-infrared light-emitting metal halide with red light excitation response and wide-band excitation. The preparation method is simple, easy to operate, low in equipment cost and pollution-free.

[0006] A third objective of this invention is to provide the application of the aforementioned broadband-excited near-infrared light-emitting metal halide with red light excitation response in near-infrared light source display devices.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] A broadband-excited near-infrared luminescent metal halide with a red light excitation response, the chemical formula of the metal halide being Rb. 2-x Cs x Hf 1-y Mo y Cl6, where 0≤x≤2; 0<y≤1.

[0009] This metal halide can be considered as Mo doped at the B site within an A2BX6 type vacancy-ordered double perovskite Rb2HfCl6 matrix. 4+ Ions, and the introduction of alkali metal Cs at the A site. + Mo 4+ The dd transition imparts near-infrared luminescence properties to this metal halide, while Cs + The introduction of this technology allows for the formation of Rb at site A. + -Cs + Binary alloys effectively improve the photoluminescence quantum efficiency (PLQY) of materials.

[0010] Preferred, best Mo 4+ The doping ratio is 15%, in 15% Mo 4+ Cs based on doping + The optimal alloying ratio is 50%, at which point x = 1 and y = 0.15, meaning the optimal crystal chemical composition is RbCsHf. 0.85 Mo 0.15 Cl6 exhibits good crystallinity and high luminescence efficiency.

[0011] The present invention also provides a method for preparing the above-mentioned near-infrared luminescent metal halide, comprising the following steps:

[0012] (1) Mix tetravalent hafnium compound and pentavalent molybdenum compound with hydrogen chloride solution and heat to dissolve, to obtain green transparent solution A;

[0013] (2) Mix the monovalent rubidium compound and the monovalent cesium compound with hydrogen chloride solution and heat to dissolve them to obtain a colorless and transparent solution B;

[0014] (3) Slowly add solution B to solution A, heat and stir, and wait for precipitate to form;

[0015] (4) The precipitate precipitated in step (3) is washed and dried with an organic solvent to obtain the broadband excited near-infrared luminescent metal halide with red light excitation response.

[0016] Preferably, in step (1), the tetravalent hafnium compound is selected from at least one of HfCl4, HfO2, Hf(OH)4, and the pentavalent molybdenum compound is selected from MoCl5.

[0017] Preferably, in step (2), the monovalent rubidium compound is selected from at least one of RbCl, Rb2O, Rb2CO3, RbOH, and the monovalent cesium compound is selected from at least one of CsCl, Cs2O, Cs2CO3, CsHCO3 and CsOH.

[0018] Preferably, the concentration of the hydrogen chloride solution in steps (1) and (2) is ≥ 37wt%.

[0019] Preferably, the molar ratio of the monovalent rubidium compound, the monovalent cesium compound, the tetravalent hafnium compound, the pentavalent molybdenum compound and the hydrogen chloride solution is 2-x: x: 1-y: y: 6; wherein the monovalent rubidium compound is counted in terms of rubidium atoms, the monovalent cesium compound is counted in terms of cesium atoms, the tetravalent hafnium compound is counted in terms of hafnium atoms, the pentavalent molybdenum compound is counted in terms of molybdenum atoms, and the hydrogen chloride is counted in terms of chlorine atoms, 0≤x≤2, 0

[0020] Preferably, in step (4), the heating temperature is 50-70℃.

[0021] Preferably, in step (4), the organic solvent is at least one of isopropyl alcohol and anhydrous ethanol.

[0022] Preferably, in step (4), oven drying is used, the temperature is 50-70℃, and the drying time is 6-10h.

[0023] The application also provides a near-infrared luminescent metal halide with red light excitation response and wide spectral band excitation of the above structure, and the application of the near-infrared luminescent metal halide prepared by the above preparation method in near-infrared light source display devices.

[0024] Compared with the prior art, the application has the following beneficial effects:

[0025] (1) The application uses transition metal ions Mo 4+ The near-infrared luminescent metal halide doped with hafnium-based vacancy ordered double perovskite Rb2HfCl6 has no toxicity relative to traditional lead-based halide perovskite, and has good crystallinity and uniformity;

[0026] (2) The application uses a simple solution co-precipitation method, which has a simple synthesis process, can be prepared in batches, and can be industrialized;

[0027] (3) The near-infrared metal halide of the present application has a wide-band near-infrared light of 800-1400 nm with an emission center at 925 nm, and has a wide-band excitation response, and can be excited by ultraviolet-blue-red light, so that the fluorescent conversion type light emitting diode prepared by packaging the near-infrared metal halide of the present application has a wide application prospect in many fields such as night vision lighting, biological medical imaging, etc. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 X-ray diffraction patterns of metal halides of Examples 1-11;

[0029] Figure 2 Comparison chart of luminescence intensity of metal halides of Examples 1-6 and relative PLQY of metal halides of Examples 7-11;

[0030] Figure 3 X-ray photoelectron spectroscopy of metal halides of Example 3 and Example 9;

[0031] Figure 4 High-resolution X-ray photoelectron spectroscopy of Mo 3d of Example 9;

[0032] Figure 5 Comparison of excitation and emission spectra of metal halides of Example 3 and Example 9;

[0033] Figure 6 Photoluminescence quantum yield result chart of metal halides of Example 3 and Example 9;

[0034] Figure 7 Device schematic diagram for biological imaging using the material of Example 9 of the present application;

[0035] Figure 8 is Figure 7 Experimental result chart for biological imaging device application. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be described below in conjunction with the embodiments and the drawings, but do not constitute a limitation on the protection scope of the present application.

[0037] In the description of the present application, unless otherwise explicitly limited, the words of heating, cleaning, weighing, etc. should be understood in a broad sense, and the skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical solutions.

[0038] In the description of the application, the description of the terms "some embodiments", "examples", and the like means that the specific methods, materials described in connection with the embodiments or examples are included in at least one embodiment or example of the application. In this specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific methods, materials described can be combined in any appropriate manner in any one or more embodiments or examples.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0040] The test methods used in the embodiments of the application are conventional methods unless otherwise specified; the materials, reagents, etc. used are commercially available reagents and materials unless otherwise specified.

[0041] The application provides a near-infrared luminescent metal halide with a wide spectral band excitation of red light excitation response, and the chemical composition formula of the metal halide is Rb 2-x Cs x Hf 1-y Mo y Cl6, wherein 0≤x≤2; 0 4+ The ion is doped in the B site and the alkali metal Cs + is introduced in the A site in the A2BX6 type vacancy-ordered double perovskite Rb2HfCl6 matrix. 4+ The d-d transition of the Mo + ion endows the metal halide with near-infrared luminescent properties, and the introduction of Cs + forms a Rb + -Cs 0.85 binary alloy in the A site, effectively improving the photoluminescence quantum efficiency (PLQY) of the material.

[0042] Preferably, the optimal doping ratio is x=1, y=0.15, that is, the optimal crystal chemical composition formula is RbCsHf 0.15 Mo 0.85 Cl6, at which the luminescence quantum efficiency is best.

[0043] The application also provides a preparation method of the above-mentioned near-infrared luminescent metal halide, comprising the following steps:

[0044] (1) mixing and heating a tetravalent hafnium compound and a pentavalent molybdenum compound with a hydrogen chloride solution to dissolve, to obtain a green transparent solution A; wherein the tetravalent hafnium compound can be at least one of HfCl4, HfO2, Hf(OH)4, and the pentavalent molybdenum compound can be MoCl5.

[0045] (2) mixing and heating a monovalent rubidium compound and a monovalent cesium compound with a hydrogen chloride solution to dissolve, to obtain a colorless transparent solution B; wherein the monovalent rubidium compound can be at least one of RbCl, Rb2O, Rb2CO3, RbOH, and the monovalent cesium compound can be at least one of CsCl, Cs2O, Cs2CO3, CsHCO3 and CsOH.

[0046] The concentration of the hydrogen chloride solution used in steps (1) and (2) is ≥ 37wt%, and a higher concentration is used to facilitate the reduction of Mo 5+ to Mo 4+ .

[0047] (3) slowly dropping solution B into solution A, heating and stirring, and waiting for the precipitation to be precipitated, which can be microcrystalline or powder according to the temperature and the ratio. Preferably, the heating temperature is 50-70℃, which facilitates the precipitation of microcrystalline products. Preferably, the molar ratio of the monovalent rubidium compound, the monovalent cesium compound, the tetravalent hafnium compound, the pentavalent molybdenum compound and the hydrogen halide is 2-x: x: 1-y: y: 6; wherein the monovalent rubidium compound is counted in rubidium atoms, the monovalent cesium compound is counted in cesium atoms, the tetravalent hafnium compound is counted in hafnium atoms, the pentavalent molybdenum compound is counted in molybdenum atoms, and the hydrogen chloride is counted in chlorine atoms, 0≤x≤2, 0

[0048] (4) washing and drying the precipitate precipitated in step (3) with an organic solvent to obtain the near-infrared luminescent metal halide with red excitation response and wide-spectrum band excitation. The organic solvent that can be used is isopropyl alcohol or anhydrous ethanol, etc. Preferably, drying is carried out in an oven, the temperature is 50-70℃, and the drying time is 6-10h to avoid damaging the morphology of the product and maintaining good luminescent properties.

[0049] The following will be described with specific examples.

[0050] Example 1

[0051] This example provides a near-infrared luminescent material with a chemical composition formula of Rb2Hf 0.95 Mo 0.05 Cl6, and the preparation method of the material is as follows:

[0052] Take 0.95 mmol hafnium tetrachloride and 0.05 mmol molybdenum pentachloride to be dissolved in 3 mL 37wt% hydrogen chloride solution, heated and stirred (300 rpm) at 60°C to obtain green transparent solution A; then take 2 mmol rubidium chloride to be dissolved in 3 mL 37wt% hydrogen chloride solution, heated and stirred (300 rpm) at 60°C to obtain colorless transparent solution B; then slowly drop solution B into solution A, heated and stirred (300 rpm) at 60°C for 2h to make the raw materials fully react, and precipitate is separated out; finally, the precipitate is filtered and washed with isopropyl alcohol for three times, and dried in a 60°C oven for 6h to obtain Rb2Hf 0.95 Mo 0.05 Cl6microcrystals.

[0053] Example 2

[0054] This example provides a near-infrared luminescent material with a chemical composition of Rb2Hf 0.9 Mo 0.1 Cl6, and the preparation method of the material is as follows:

[0055] Take 0.9 mmol hafnium tetrachloride and 0.1 mmol molybdenum pentachloride to be dissolved in 3 mL 37wt% hydrogen chloride solution, heated and stirred (300 rpm) at 60°C to obtain green transparent solution A; then take 2 mmol rubidium chloride to be dissolved in 3 mL 37wt% hydrogen chloride solution, heated and stirred (300 rpm) at 60°C to obtain colorless transparent solution B; then slowly drop solution B into solution A, heated and stirred (300 rpm) at 60°C for 2h to make the raw materials fully react, and precipitate is separated out; finally, the precipitate is filtered and washed with isopropyl alcohol for three times, and dried in a 60°C oven for 6h to obtain Rb2Hf 0.9 Mo 0.1 Cl6microcrystals.

[0056] Example 3

[0057] This example provides a near-infrared luminescent material with a chemical composition of Rb2Hf 0.85 Mo 0.15 Cl6, and the preparation method of the material is as follows:

[0058] Take 0.85 mmol hafnium tetrachloride and 0.15 mmol molybdenum pentachloride to be dissolved in 3 mL of 37 wt% hydrogen chloride solution, heated and stirred (300 rpm) at 60°C to obtain green transparent solution A; then take 2 mmol rubidium chloride to be dissolved in 3 mL of 37 wt% hydrogen chloride solution, heated and stirred (300 rpm) at 60°C to obtain colorless transparent solution B; then slowly drop solution B into solution A, heated and stirred (300 rpm) at 60°C for 2 h to make the raw materials fully react, and precipitate is separated out; finally, the precipitate is filtered, washed with isopropyl alcohol three times, and dried in a 60°C oven for 6 h to obtain Rb2Hf 0.85 Mo 0.15 Cl6microcrystals.

[0059] Example 4

[0060] This example provides a near-infrared luminescent material with a chemical composition of Rb2Hf 0.8 Mo 0.2 Cl6, and the preparation method of the material is as follows:

[0061] Take 0.8 mmol hafnium tetrachloride and 0.2 mmol molybdenum pentachloride to be dissolved in 3 mL of 37 wt% hydrogen chloride solution, heated and stirred (300 rpm) at 60°C to obtain green transparent solution A; then take 2 mmol rubidium chloride to be dissolved in 3 mL of 37 wt% hydrogen chloride solution, heated and stirred (300 rpm) at 60°C to obtain colorless transparent solution B; then slowly drop solution B into solution A, heated and stirred (300 rpm) at 60°C for 2 h to make the raw materials fully react, and precipitate is separated out; finally, the precipitate is filtered, washed with isopropyl alcohol three times, and dried in a 60°C oven for 6 h to obtain Rb2Hf 0.8 Mo 0.2 Cl6microcrystals.

[0062] Example 5

[0063] This example provides a near-infrared luminescent material with a chemical composition of Rb2Hf 0.75 Mo 0.25 Cl6, and the preparation method of the material is as follows:

[0064] Take 0.75 mmol hafnium tetrachloride and 0.25 mmol molybdenum pentachloride to be dissolved in 3 mL of 37 wt% hydrogen chloride solution, heated and stirred (300 rpm) at 60°C to obtain green transparent solution A; then take 2 mmol rubidium chloride to be dissolved in 3 mL of 37 wt% hydrogen chloride solution, heated and stirred (300 rpm) at 60°C to obtain colorless transparent solution B; then slowly drop solution B into solution A, heated and stirred (300 rpm) at 60°C for 2 h to make the raw materials fully react, and precipitate is separated out; finally, the precipitate is filtered, washed with isopropyl alcohol three times, and dried in a 60°C oven for 6 h to obtain Rb2Hf0.75 Mo 0.25 Cl6microcrystals.

[0065] Example 6

[0066] This example provides a near-infrared luminescent material with a chemical composition of Rb2Hf 0.7 Mo 0.3 Cl6, which is prepared as follows:

[0067] Take 0.7 mmol hafnium tetrachloride and 0.3 mmol molybdenum pentachloride and dissolve them in 3 mL of 37 wt% hydrogen chloride solution, heat and stir (300 rpm) at 60°C to obtain a green transparent solution A; then take 2 mmol rubidium chloride and dissolve it in 3 mL of 37 wt% hydrogen chloride solution, heat and stir (300 rpm) at 60°C to obtain a colorless transparent solution B; then slowly add solution B to solution A, heat and stir (300 rpm) at 60°C for 2 h to make the raw materials fully react, and precipitate is separated out; finally, filter the precipitate, wash it with isopropyl alcohol three times, and dry it in a 60°C oven for 6 h to obtain Rb2Hf 0.7 Mo 0.3 Cl6microcrystals.

[0068] Example 7

[0069] This example provides a near-infrared luminescent material with a chemical composition of Rb 1.8 Cs 0.2 Hf 0.85 Mo 0.15 Cl6, which is prepared as follows:

[0070] Take 0.85 mmol hafnium tetrachloride and 0.15 mmol molybdenum pentachloride and dissolve them in 3 mL of 37 wt% hydrogen chloride solution, heat and stir (300 rpm) at 60°C to obtain a green transparent solution A; then take 1.8 mmol rubidium chloride and 0.2 mmol cesium chloride and dissolve them in 3 mL of 37 wt% hydrogen chloride solution, heat and stir (300 rpm) at 60°C to obtain a colorless transparent solution B; then slowly add solution B to solution A, heat and stir (300 rpm) at 60°C for 2 h to make the raw materials fully react, and precipitate is separated out; finally, filter the precipitate, wash it with isopropyl alcohol three times, and dry it in a 60°C oven for 6 h to obtain Rb 1.8 Cs 0.2 Hf 0.85 Mo 0.15 Cl6microcrystals.

[0071] Example 8

[0072] This example provides a near-infrared luminescent material with a chemical composition of Rb 1.4 Cs 0.6 Hf 0.85 Mo0.15 The near-infrared luminescent material of Cl6 is prepared by the following method:

[0073] 0.85 mmol hafnium tetrachloride and 0.15 mmol molybdenum pentachloride were dissolved in 3 mL of 37 wt% hydrogen chloride solution and heated and stirred at 60 °C (300 rpm) to obtain a green transparent solution A. Then, 1.4 mmol rubidium chloride and 0.6 mmol cesium chloride were dissolved in 3 mL of 37 wt% hydrogen chloride solution and heated and stirred at 60 °C (300 rpm) to obtain a colorless transparent solution B. Solution B was then slowly added dropwise to solution A, and the mixture was heated and stirred at 60 °C (300 rpm) for 2 h to allow the reactants to react fully, resulting in a precipitate. Finally, the precipitate was filtered, washed three times with isopropanol, and dried in a 60 °C oven for 6 h to obtain Rb. 1.4 Cs 0.6 Hf 0.85 Mo 0.15 Cl6 microcrystals.

[0074] Example 9

[0075] This embodiment provides a chemical formula RbCsHf 0.85 Mo 0.15 The near-infrared luminescent material of Cl6 is prepared by the following method:

[0076] 0.85 mmol of hafnium tetrachloride and 0.15 mmol of molybdenum pentachloride were dissolved in 3 mL of 37 wt% hydrogen chloride solution and heated and stirred at 60 °C (300 rpm) to obtain a green transparent solution A. Then, 1 mmol of rubidium chloride and 1 mmol of cesium chloride were dissolved in 3 mL of 37 wt% hydrogen chloride solution and heated and stirred at 60 °C (300 rpm) to obtain a colorless transparent solution B. Solution B was then slowly added dropwise to solution A, and the mixture was heated and stirred at 60 °C (300 rpm) for 2 h to allow the reactants to react fully, resulting in a precipitate. Finally, the precipitate was filtered, washed three times with isopropanol, and dried in a 60 °C oven for 6 h to obtain RbCsHf. 0.85 Mo 0.15 Cl6 microcrystals.

[0077] Example 10

[0078] This embodiment provides a chemical formula Rb 0.6 Cs 1.4 Hf 0.85 Mo 0.15 The near-infrared luminescent material of Cl6 is prepared by the following method:

[0079] Take 0.85 mmol hafnium tetrachloride and 0.15 mmol molybdenum pentachloride to be dissolved in 3 mL 37 wt% hydrogen chloride solution, heated and stirred (300 rpm) at 60°C to obtain green transparent solution A; then take 0.6 mmol rubidium chloride and 1.4 mmol cesium chloride to be dissolved in 3 mL 37 wt% hydrogen chloride solution, heated and stirred (300 rpm) at 60°C to obtain colorless transparent solution B; then slowly drop solution B into solution A, heated and stirred (300 rpm) at 60°C for 2 h to make the raw materials fully react, and precipitate is separated out; finally, the precipitate is filtered, washed with isopropyl alcohol three times, and dried in a 60°C oven for 6 h to obtain Rb 0.6 Cs 1.4 Hf 0.85 Mo 0.15 Cl6microcrystal.

[0080] Example 11

[0081] This example provides a near-infrared luminescent material with chemical composition Rb 0.2 Cs 1.8 Hf 0.85 Mo 0.15 Cl6, and the preparation method of the material is as follows:

[0082] Take 0.85 mmol hafnium tetrachloride and 0.15 mmol molybdenum pentachloride to be dissolved in 3 mL 37 wt% hydrogen chloride solution, heated and stirred (300 rpm) at 60°C to obtain green transparent solution A; then take 0.2 mmol rubidium chloride and 1.8 mmol cesium chloride to be dissolved in 3 mL 37 wt% hydrogen chloride solution, heated and stirred (300 rpm) at 60°C to obtain colorless transparent solution B; then slowly drop solution B into solution A, heated and stirred (300 rpm) at 60°C for 2 h to make the raw materials fully react, and precipitate is separated out; finally, the precipitate is filtered, washed with isopropyl alcohol three times, and dried in a 60°C oven for 6 h to obtain Rb 0.2 Cs 1.8 Hf 0.85 Mo 0.15 Cl6microcrystal.

[0083] Table 1 below is a description of the chemical composition of the metal halide prepared in Examples 1-11.

[0084] Table 1 Metal halide chemical composition of Examples 1-11

[0085] x Cs + Alloying ratio (%)]]> y Mo 4+ Doping ratio (%)]]> Rb 2-x Cs x Hf 1-y Mo y Cl6]]> Example 1 0 0 0.05 5 [Rb2Hf 0.95 Mo 0.05 Cl6]]> Example 2 0 0 0.1 10 [Rb2Hf 0.9 Mo 0.1 Cl6]]> Example 3 0 0 0.15 15 [Rb2Hf 0.85 Mo 0.15 Cl6]]> Example 4 0 0 0.2 20 [Rb2Hf 0.8 Mo 0.2 Cl6]]> Example 5 0 0 0.25 25 [Rb2Hf 0.75 Mo 0.25 Cl6]]> Example 6 0 0 0.3 30 [Rb2Hf 0.7 Mo 0.3 Cl6]]> Example 7 0.2 10 0.15 15 Rb 1.8 Cs 0.2 Hf 0.85 Mo 0.15 Cl6]]> Example 8 0.6 30 0.15 15 Rb 1.4 Cs 0.6 Hf 0.85 Mo 0.15 Cl6]]> Example 9 1 50 0.15 15 [RbCsHf 0.85 Mo 0.15 Cl6]]> Example 10 1.4 70 0.15 15 Rb 0.6 Cs 1.4 Hf 0.85 Mo 0.15 Cl6]]> Example 11 1.8 90 0.15 15 Rb 0.2 Cs 1.8 Hf 0.85 Mo 0.15 Cl6]]>

[0086] Performance test:

[0087] (1) The prepared product is subjected to X-ray powder diffraction, X-ray photoelectron spectroscopy, excitation spectrum and emission spectrum, and photoluminescence quantum yield determination. The results are as follows:Figures 1-6 As shown.

[0088] The X-ray diffraction (XRD) patterns of Examples 1-11 were measured using a Bruker D8 Advance Davinci X-ray diffractometer, with the XRD pattern of undoped hafnium-based vacancy-ordered double perovskite Rb₂HfCl₆ used as a reference for comparison. Figure 1 As shown, the XRD patterns of all embodiments exhibit the same diffraction peaks, which are consistent with the XRD pattern of Rb₂HfCl₆ with space group Fm-3m. No obvious impurity peaks were observed, with only minor shifts in diffraction angles due to differences in the radii of the dopant ions. These results demonstrate that well-crystallized near-infrared metal halides can be obtained using a simple solution co-precipitation method.

[0089] The near-infrared luminescence intensity of Examples 1-6 was measured using a Princeton HRS-500 fluorescence spectrometer (equipped with an integrating sphere). Figure 2 (As shown by the red curve), when Mo 4+ The near-infrared luminescence intensity is highest when the doping concentration is 15% (i.e., y = 0.15), and concentration quenching occurs when the doping concentration exceeds 15% (y > 0.15). Furthermore, when Mo is fixed... 4+ Based on a doping concentration of 15%, Cs was applied to the A site. + The alloyed samples from Examples 7-11 were subjected to PLQY testing. Figure 2 (Middle blue curve). The results show that when Cs + When the alloying ratio reaches 50% (i.e., x = 1), the relative PLQY of the sample reaches its peak. In summary, Example 3 (Rb2Hf) 0.85 Mo 0.15 Cl6) and Example 9 (RbCsHf) 0.85 Mo 0.15 Cl6) was identified as the optimal sample.

[0090] XPS spectra of Examples 3 and 9 were obtained by X-ray photoelectron spectroscopy using an AXIS SUPPAX X-ray photoelectron spectroscopy instrument. Figure 3 As shown, in the transition metal ion Mo 4+ and alkali metal ions Cs + After alloying, in addition to the characteristic Rb 3d, Hf 4f and Cl 2p signal peaks of the matrix Rb2HfCl6, characteristic signal peaks of Mo 3d and Cs 3d also appeared. Figure 4 The fine XPS spectrum of Mo 3d in Example 9 is shown, with peaks at 235 eV and 232 eV attributed to Mo 3d. 3 / 2 and Mo 3d 5 / 2 This confirms that Mo is in the +4 valence state in metal halides.

[0091] The excitation and emission spectra of Examples 3 and 9 were obtained using an Edinburgh FLS1000 analyzer. Figure 5 As shown, under 343 nm excitation, both Examples 3 and 9 exhibited broadband near-infrared emission spectra centered at 925 nm, ranging from 800 to 1400 nm. Further analysis of the excitation spectrum at 925 nm revealed four main excitation bands centered at 300, 385, 440, and 750 nm. The highest energy excitation peak can be attributed to charge transfer transitions; the remaining excitation peaks centered at 385, 440, and 750 nm are attributed to Mo doping. 4+ of 3 T 1g → 1 T 2g / 1 E g , 3 T 1g → 3 T 2g and 3 T 1g → 3 T 1g (P) transition. Unlike near-infrared luminescent materials that typically rely on high-energy excitation from ultraviolet or blue light, the metal halides of this invention benefit from their unique excitation spectral characteristics, exhibiting an effective red light excitation response and broad-band excitation properties, thus providing greater flexibility in practical applications of near-infrared light sources.

[0092] The PLQY of Examples 3 and 9 was determined using an integrating sphere on an Edinburgh FLS1000 system. Figure 6 As shown in (a) and (b), under excitation by a 298 nm xenon lamp source, Example 3 (Rb2Hf) 0.85 Mo 0.15 The PLQY of Cl6 was 70.66%, and that of Example 9 (RbCsHf) was 70.66%. 0.85 Mo 0.15 The PLQY of Cl6 was 82.89%, indicating that the alkali metal ion Cs + The introduction of [a specific technology / method] can effectively optimize luminous efficiency. Specifically, such as... Figure 6 As shown in (c), under excitation by a 763nm xenon lamp light source, Example 9 (RbCsHf0) 85 Mo 0.15 The PLQY of Cl6 is still as high as 77.64%, which further proves that the near-infrared metal halide prepared in this invention has a good red light excitation response.

[0093] (2) Take 10 mg of RbCsHf prepared in Example 9 0.85 Mo 0.15C16 microcrystal is mixed with epoxy resin uniformly and packaged on a 365nm emitting ultraviolet LED chip to prepare a fluorescent conversion type near-infrared light emitting diode. Subsequently, the prepared packaging material is applied to near-infrared imaging.

[0094] Figure 7 An experimental device for biological imaging using the prepared pc-LED is shown. In a dark environment, the pc-LED emits strong near-infrared light to irradiate a target object, a near-infrared camera is used to collect images in real time, and the images are displayed on a computer screen through data transmission.

[0095] Figure 8 To take a photo of a palm by using the above imaging device, due to the strong absorption of blood to near-infrared light and the weak absorption of surrounding skin, fat and other tissues to light, the details of blood vessels and veins can be clearly identified in the image, verifying the feasibility of the near-infrared metal halide based on the application in the application of near-infrared biological imaging.

[0096] The technical features of the above-described embodiments can be combined arbitrarily, and to make the description concise, all possible combinations of the technical features in the above-described embodiments are not described, however, as long as the combinations of the technical features do not exist contradictions, they should be considered as the scope of the present application.

[0097] The above-described embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the scope of the present application. Therefore, the scope of protection of the present application should be subject to the appended claims.

Claims

1. A broadband-excited near-infrared luminescent metal halide with a red light excitation response, characterized in that, The chemical formula of the metal halide is Rb 2-x Cs x Hf 1-y Mo y Cl6, where 0≤x≤2, 0<y≤1.

2. The method for preparing a broadband-excited near-infrared luminescent metal halide with red light excitation response as described in claim 1, characterized in that, Includes the following steps: (1) Mix tetravalent hafnium compound and pentavalent molybdenum compound with hydrogen chloride solution and heat to dissolve, to obtain green transparent solution A; (2) Mix the monovalent rubidium compound and the monovalent cesium compound with hydrogen chloride solution and heat to dissolve them to obtain a colorless and transparent solution B; (3) Slowly add solution B to solution A, heat and stir, and wait for precipitate to form. (4) The precipitate precipitated in step (3) is washed and dried with an organic solvent to obtain the broadband excited near-infrared luminescent metal halide with red light excitation response.

3. The preparation method according to claim 2, characterized in that, In step (1), The tetravalent hafnium compound is selected from at least one of HfCl4, HfO2, and Hf(OH)4. The pentavalent molybdenum compound is selected from MoCl5.

4. The preparation method according to claim 2, characterized in that, In step (2), The monovalent rubidium compound is selected from at least one of RbCl, Rb₂O, Rb₂CO₃, and RbOH. The monovalent cesium compound is selected from at least one of CsCl, Cs2O, Cs2CO3, CsHCO3, and CsOH.

5. The preparation method according to claim 2, characterized in that, The concentration of the hydrogen chloride solution is ≥37wt%.

6. The preparation method according to claim 2, characterized in that, The molar ratio of the monovalent rubidium compound, monovalent cesium compound, tetravalent hafnium compound, pentavalent molybdenum compound, and hydrogen chloride solution is 2-x:x:1-y:y:6; Wherein, the monovalent rubidium compound is calculated as rubidium atoms, the monovalent cesium compound as cesium atoms, the tetravalent hafnium compound as hafnium atoms, the pentavalent molybdenum compound as molybdenum atoms, the hydrogen chloride as chlorine atoms, 0≤x≤2, 0<y≤1.

7. The preparation method according to claim 2, characterized in that, In step (3), the heating temperature is 50-70℃.

8. The preparation method according to claim 2, characterized in that, In step (4), the organic solvent is at least one of isopropanol and anhydrous ethanol.

9. The preparation method according to claim 2, characterized in that, In step (4), an oven is used for drying at a temperature of 50-70℃ for 6-10 hours.

10. The application of the broadband excited near-infrared luminescent metal halide with red light excitation response as described in claim 1, or the broadband excited near-infrared luminescent metal halide with red light excitation response prepared by the preparation method of any one of claims 2-9, in near-infrared light source display devices.

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