A Cs2AgInCl6:xFe 3+ Infrared luminescent materials, their preparation methods and applications

Abstract

This invention discloses a Cs2AgInCl6:xFe 3+ Infrared luminescent materials, their preparation methods, and applications. Among them, Cs₂AgInCl₆:xFe 3+ Infrared luminescent materials possess unique properties such as high chemical stability and the ability to be effectively excited by 250–650 nm light to produce ultra-wide near-infrared emission, making them applicable in near-infrared fluorescence imaging, fiber optic communication, and anti-counterfeiting. They utilize ion-doped Fe... 3+ The luminescent center is used instead of the self-trapped exciton. Doped Fe 3+ The ion has a half-filled electronic structure (3d). 5 Therefore, it can present 4 T1( 4 G)→ 6 A1( 6 The S-transition emits near-infrared light. The preparation method provided by this invention does not employ harsh synthesis conditions of high pressure and reducing agents. Instead, it utilizes a solvothermal method and Cs₂AgInCl₆:xFe under normal pressure and an oxidizing atmosphere. 3+ The required chemical raw materials can be used to synthesize luminescent materials. The preparation conditions are simple and can be mass-produced industrially.

Description

Technical Field

[0001] This invention belongs to the field of near-infrared luminescent materials technology, specifically relating to a Cs2AgInCl6:xFe 3+ Infrared luminescent materials, their preparation methods, and applications. Background Technology

[0002] With the rapid advancement of technology, the demand for near-infrared emitting materials adapted to the ever-evolving portable devices is increasing, making the development and optimization of near-infrared luminescent materials a key research focus in the field of luminescent materials. The luminescence of ion-doped near-infrared luminescent materials is typically based on the electronic transitions of ions. When these materials are excited, electrons transition from the ground state to an excited state, then return to a lower excited state through non-radiative relaxation, releasing photons in the process. The doped ions act as sensitizers and activators. Different materials and ion-doped systems offer a wide range of luminescent properties, enabling applications such as biomedical imaging and photoelectric detection. In current research, Cr... 3+ Doped phosphors are often chosen as the primary materials for near-infrared emission. Cr 3+ A broad emission band in the 650–1200 nm range can be generated in a relatively weak octahedral crystal field. However, its limitation lies in the fact that, firstly, during the phosphor preparation process, Cr… 3+ It may be oxidized to Cr 4+ Cr 5+ or Cr 6+ The inevitable energy transfer between ions leads to non-radiative energy loss, ultimately reducing luminescence efficiency and limiting its use in certain fields. Secondly, the use of chromium may increase the risk of biological poisoning, especially in cases requiring long-term in vivo use.

[0003] Therefore, it is urgent to research and develop chromium-free, environmentally friendly near-infrared luminescent materials that are safe both in vitro and in vivo. Summary of the Invention

[0004] The purpose of this invention is to provide a Cs2AgInCl6:xFe 3+ Infrared luminescent materials, their preparation methods, and applications. Among them, Cs₂AgInCl₆:xFe 3+ Infrared luminescent materials exhibit high chemical stability and an ultra-wide near-infrared emission band. Furthermore, the preparation method provided by this invention requires mature and simple equipment, facilitating mass production.

[0005] The technical solution of the present invention is as follows:

[0006] A Cs2AgInCl6:xFe 3+Infrared luminescent materials have the general chemical formula Cs₂AgInCl₆:xFe 3+ , 0≤x≤1.

[0007] In some preferred embodiments, Cs2AgInCl6:xFe 3+ The crystal structure of the infrared luminescent material is cubic with space group Fm-3m.

[0008] In some preferred embodiments, Cs2AgInCl6:xFe 3+ The infrared luminescent material is obtained by a solvothermal reaction of cesium-containing compounds, silver-containing compounds, indium-containing compounds, chlorine-containing compounds and iron-containing compounds in an oxidizing atmosphere. The temperature of the solvothermal reaction is 150-200℃ and the holding time of the solvothermal reaction is 5-18 hours.

[0009] In some preferred embodiments, the cesium-containing compound is at least one of cesium carbonate, cesium acetate, and cesium chloride; the silver-containing compound is at least one of silver carbonate, silver chloride, and silver iodide; the indium-containing compound is at least one of indium trichloride tetrahydrate, indium iodide, and indium acetate; the iron-containing compound is at least one of ferric chloride, ferric phosphate, ferric oxide, and ferric citrate; and the chlorine-containing compound is hydrochloric acid and / or dichloroacetic acid.

[0010] A Cs2AgInCl6:xFe 3+ The preparation method of infrared luminescent materials includes the following steps:

[0011] Weigh out cesium-containing compounds, silver-containing compounds, indium-containing compounds, and iron-containing compounds in a molar ratio of 2:1:1:x. Relative to 1 mmol of the silver-containing compound, 1 mmol of the indium-containing compound and x mol of the iron (Fe) compound... 3+ Add 5 mL of concentrated hydrochloric acid (12 mol / L) to the compound. (The compound contains silver, indium, and iron.) 3+ The cesium-containing compound and 5 mL of concentrated hydrochloric acid were placed in a 20 mL glass bottle and stirred at room temperature for 2 hours. 5 mL of 12 mol / L concentrated hydrochloric acid was added relative to 2 mmol of the cesium-containing compound. The cesium-containing compound and 5 mL of 12 mol / L concentrated hydrochloric acid were placed in a 20 mL glass bottle and shaken for 5 minutes to mix thoroughly. Both solutions were then transferred to a polytetrafluoroethylene (PTFE) liner. Finally, a solvothermal reaction was carried out at 150–200 °C under an oxidizing atmosphere for 5–18 hours. After cooling to room temperature, the crystals were washed with anhydrous ethanol and dried to obtain the Cs₂AgInCl₆:xFe 3+ Infrared luminescent materials.

[0012] In some preferred embodiments, the heating rate of the solvothermal reaction is 2.5–5 °C / min, and the cooling rate to room temperature is 3 °C / h.

[0013] In some preferred embodiments, the oxidizing atmosphere is an oxygen atmosphere or an air atmosphere.

[0014] In some preferred embodiments, the cesium-containing compound is at least one of cesium carbonate, cesium acetate, and cesium chloride; the silver-containing compound is at least one of silver carbonate, silver chloride, and silver iodide; the indium-containing compound is at least one of indium trichloride tetrahydrate, indium iodide, and indium acetate; the iron-containing compound is at least one of ferric chloride, ferric phosphate, ferric oxide, and ferric citrate; and the chlorine-containing compound is hydrochloric acid and / or dichloroacetic acid.

[0015] The above Cs2AgInCl6:xFe 3+ Application of infrared luminescent materials in near-infrared fluorescence imaging.

[0016] The above Cs2AgInCl6:xFe 3+ Application of infrared luminescent materials in optical fiber communication.

[0017] The present invention has at least the following beneficial effects:

[0018] (1) The Cs2AgInCl6:xFe provided by this invention 3+ Infrared luminescent materials possess unique properties such as high chemical stability and the ability to be effectively excited by 250–650 nm light to produce ultra-wide near-infrared emission, making them applicable in near-infrared fluorescence imaging, fiber optic communication, and anti-counterfeiting. They utilize ion-doped Fe... 3+ The luminescent center is used instead of the self-trapped exciton. Doped Fe 3+ The ion has a half-filled electronic structure (3d). 5 Therefore, it can present 4 T1( 4 G)→ 6 A1( 6 The S transition emits near-infrared light.

[0019] (2) The preparation method provided by this invention does not employ harsh synthesis conditions of high pressure and reducing properties. Instead, it uses a solvothermal method and Cs2AgInCl6:xFe under normal pressure and an oxidizing atmosphere. 3+ The required chemical raw materials can be used to synthesize luminescent materials. The preparation conditions are simple and it can be mass-produced industrially. Attached Figure Description

[0020] Figure 1 The Cs2AgInCl6:xFe prepared in Example 1 3+X-ray diffraction patterns of infrared luminescent materials (x = 0.2, 0.4, 0.6, 0.8, 1);

[0021] Figure 2 The Cs2AgInCl6:xFe prepared in Example 1 3+ Diffuse reflectance spectra of infrared luminescent materials (x = 0.2, 0.4, 0.6, 0.8, 1);

[0022] Figure 3 The Cs2AgInCl6:xFe prepared in Example 1 3+ Excitation spectra of infrared luminescent materials (x = 0.2, 0.4, 0.6, 0.8, 1);

[0023] Figure 4 The Cs2AgInCl6:xFe prepared in Example 1 3+ Emission spectra of infrared luminescent materials (x = 0.2, 0.4, 0.6, 0.8, 1). Detailed Implementation

[0024] The technical solution of the present invention will be further explained and described below through specific embodiments.

[0025] In the following embodiments, the water used can be one or more of distilled water, purified water, and drinking water; unless otherwise specified, the detection methods in the following embodiments are conventional detection methods; unless otherwise specified, the reagents in the following embodiments are all purchased from commercial channels.

[0026] Example 1

[0027] This embodiment provides a Cs2AgInCl6:xFe 3+ Infrared luminescent materials and their preparation methods, where x = 0.2, 0.4, 0.6, 0.8, 1. Among the various compound raw materials, the cesium-containing compound is cesium chloride (CsCl), the silver-containing compound is silver chloride (AgCl), the indium-containing compound is indium trichloride tetrahydrate (InCl3·4H2O), the iron-containing compound is ferric oxide (Fe2O3), and the chlorine-containing compound is concentrated hydrochloric acid (HCl).

[0028] Its preparation method includes the following steps:

[0029] Weigh out cesium-containing compounds, silver-containing compounds, indium-containing compounds, and iron-containing compounds in a molar ratio of 2:1:1:x. Relative to 1 mmol of the silver-containing compound, 1 mmol of the indium-containing compound and x mol of the iron (Fe) compound... 3+ Add 5 mL of concentrated hydrochloric acid (12 mol / L) to the compound. (The compound contains silver, indium, and iron.) 3+The cesium-containing compound and 5 mL of concentrated hydrochloric acid were placed in a 20 mL glass bottle and stirred at room temperature for 2 hours. 5 mL of 12 mol / L concentrated hydrochloric acid was added relative to 2 mmol of the cesium-containing compound. The cesium-containing compound and 5 mL of 12 mol / L concentrated hydrochloric acid were placed in a 20 mL glass bottle and shaken for 5 minutes to mix thoroughly. Both solutions were then transferred to a polytetrafluoroethylene (PTFE) liner. The reactor was placed in an oven and heated from 25 °C to 180 °C at a rate of 3 °C per minute under air, and maintained at 180 °C for 12 hours. The sample was then cooled to room temperature at a rate of 3 °C per hour. After repeated washing with anhydrous ethanol and drying, Cs₂AgInCl₆:xFe₂ was obtained. 3+ Crystalline compound infrared luminescent materials.

[0030] Figure 1 The Cs2AgInCl6:xFe prepared in Example 1 3+ X-ray diffraction patterns of infrared luminescent materials (x = 0.2, 0.4, 0.6, 0.8, 1). Spectra were acquired using a Rigaku Smar / SmartLa X-ray diffractometer (Japan). During spectral acquisition, the X-ray tube operating voltage was set to 40 kV and 30 mA. Figure 1 The X-ray diffraction pattern in Example 1 shows that Cs2AgInCl6:xFe 3+ (x = 0.2, 0.4, 0.6, 0.8, 1) has a Cs₂AgInCl₆ crystal structure (ICSD#1926611). Fe 3+ The doping did not introduce impurity phases.

[0031] Figure 2 The Cs2AgInCl6:xFe prepared in Example 1 3+ Diffuse reflectance spectra of infrared luminescent materials (x = 0.2, 0.4, 0.6, 0.8, 1). The figure shows that with the increase of Fe... 3+ As concentration increases, the sample's light absorption range increases, but the rate of increase gradually decreases. From Figure 2 It can be seen that Cs2AgInCl6:xFe 3+ The infrared luminescent material (x = 0.2, 0.4, 0.6, 0.8, 1) has an absorption range of 200–650 nm. This indicates that Fe… 3+ It can exhibit excitable properties covering almost the entire visible light region in the Cs2AgInCl6 matrix.

[0032] Figure 3 The Cs2AgInCl6:xFe prepared in Example 1 3+Excitation spectra of infrared luminescent materials (x = 0.2, 0.4, 0.6, 0.8, 1). Monitoring an infrared wavelength of 1450 nm, the excitation spectra of the samples covered approximately 250 nm to 700 nm. In the excitation spectra, the maximum excitation peaks were located around 300 nm and 400 nm, respectively, which are attributed to the characteristic excitation of the Cs₂AgInCl₆ matrix and the characteristic excitation transition of iron ions. When Fe… 3+ When the ion doping concentration is low, matrix excitation (300 nm) dominates. With Fe... 3+ Increased ion doping concentration enhances the peak at 370 nm. When Fe... 3+ The sample exhibits the highest excitation intensity at an ion concentration of 0.4, indicating that the Cs₂AgInCl₆:₀.₄Fe₂O₃ ion concentration is optimal. 3+ The sample performed best.

[0033] Figure 4 The Cs2AgInCl6:xFe prepared in Example 1 3+ Photoemission spectra of infrared luminescent materials (x = 0.2, 0.4, 0.6, 0.8, 1). From Figure 4 It can be seen that under 370 nm light excitation, Cs2AgInCl6:xFe 3+ Crystals with x = 0.2, 0.4, 0.6, 0.8, 1 can emit an ultra-broad emission band with wavelengths ranging from approximately 800 nm to 1600 nm. The emission spectrum splits into two peaks, with maximum values ​​around 1360 nm and 1420 nm, corresponding to different orbital electron transitions of iron ions. The emission peak intensities vary slightly with changes in iron ion concentration. When the iron ion doping concentration is x = 0.4, Cs₂AgInCl₆:₀.₄Fe 3+ The infrared emission is strongest. This corresponds to the photoexcitation spectrum, further confirming that Cs2AgInCl6:0.4Fe... 3+ Crystals have the best infrared luminescence performance.

[0034] The above embodiments are only used to further illustrate a Cs2AgInCl6:xFe of the present invention. 3+ Infrared luminescent materials and their preparation methods are described, but the present invention is not limited to the embodiments. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A Cs2AgInCl6:xFe 3+ The application of infrared luminescent materials in near-infrared fluorescence imaging is characterized by, The Cs2AgInCl6:xFe 3+ The general chemical formula of the infrared luminescent material is Cs2AgInCl6:xFe 3+ , 0 < x ≤ 1; the Cs2AgInCl6:xFe 3+ The preparation method of infrared luminescent materials includes the following steps: Weigh out a cesium-containing compound, a silver-containing compound, an indium-containing compound, and an iron-containing compound in a molar ratio of 2:1:1:x; add 5 mL of 12 mol / L concentrated hydrochloric acid to each of 1 mmol of the silver-containing compound, 1 mmol of the indium-containing compound, and x mmol of the iron-containing compound; place the silver-containing compound, indium-containing compound, iron-containing compound, and 5 mL of 12 mol / L concentrated hydrochloric acid in a 20 mL glass bottle and stir at room temperature for 2 hours; add 5 mL of 12 mol / L concentrated hydrochloric acid to each of 2 mmol of the cesium-containing compound; place the cesium-containing compound and 5 mL of 12 mol / L concentrated hydrochloric acid in a 20 mL glass bottle and shake for 5 minutes to mix thoroughly; finally, transfer both solutions to a polytetrafluoroethylene liner; and finally, in an oxidizing atmosphere at 150-200 °C. The solvothermal reaction was carried out at a temperature of ℃ and held for 5-18 hours. After cooling to room temperature, the crystals were washed with anhydrous ethanol and dried to obtain the Cs2AgInCl6:xFe. 3+ Infrared luminescent materials.

2. The application according to claim 1, characterized in that, The Cs2AgInCl6:xFe 3+ The crystal structure of the infrared luminescent material is cubic with space group Fm-3m.

3. The application according to claim 1, characterized in that, The cesium-containing compound is at least one of cesium carbonate, cesium acetate, and cesium chloride; the silver-containing compound is at least one of silver carbonate, silver chloride, and silver iodide; the indium-containing compound is at least one of indium trichloride tetrahydrate, indium iodide, and indium acetate; and the iron-containing compound is at least one of ferric chloride, ferric phosphate, ferric oxide, and ferric citrate.

4. The application according to claim 1, characterized in that, The heating rate of the solvothermal reaction is 2.5~5 °C / min, and the cooling rate to room temperature is 3 °C / h.

5. The application according to claim 1, characterized in that, The oxidizing atmosphere is an oxygen atmosphere or an air atmosphere.

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