Cs2AgInCl6: xFe < 3 + > infrared luminescent material as well as preparation method and application thereof

Abstract

The invention discloses a Cs2AgInCl6: xFe < 3 + > infrared luminescent material as well as a preparation method and application thereof. The Cs2AgInCl6: xFe < 3 + > infrared luminescent material has the unique characteristics of high chemical stability and capability of being effectively excited by 250-650 nanometer light to generate ultra-wide near-infrared luminescence, and can be applied to the fields of near-infrared fluorescence imaging, optical fiber communication or anti-counterfeiting and the like. Ion-doped Fe < 3 + > is adopted as a light-emitting center, and self-trapping excitons are not adopted as the light-emitting center. The doped Fe < 3 + > ions have a semi-filled electronic structure (3d5), so that transition from 4T1 (4G) to 6A1 (6S) can be presented to emit near-infrared light. According to the preparation method provided by the invention, harsh synthesis conditions of high pressure and reducibility are not adopted, the luminescent material can be synthesized by adopting a solvothermal method and chemical raw materials required by Cs2AgInCl6: xFe < 3 + > under the atmosphere of normal pressure and oxidizing property, the preparation conditions are simple, and batch industrial production can be realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of near-infrared luminescent materials, and specifically relates to a Cs2AgInCl6:xFe 3+ Infrared luminescent material, preparation method and application thereof. Background Art

[0002] With the rapid advancement of science and technology, there is an increasing demand for near-infrared emitting materials that are compatible with the evolving portable devices. The development and optimization of near-infrared luminescent materials has become one of the research focuses in the field of luminescent materials. The luminescence of ion-doped near-infrared luminescent materials is usually based on the electronic transition of ions. When these materials are excited, electrons transition from the ground state to the excited state, and then return to the lower excited state through radiationless relaxation, releasing photons in the process. The doped ions act as sensitizers and activators. Different materials and ion doping systems provide a wide range of luminescent properties, which can be used in different applications such as biomedical imaging and photoelectric detection. In the current study, Cr 3+ Doped phosphors are often selected as the main materials for near-infrared luminescence. 3+ In a weak octahedral crystal field, a wide emission band in the range of 650 to 1200 nanometers can be produced. However, its limitations are that, firstly, in the process of phosphor preparation, Cr 3+ May be oxidized to Cr 4+ Cr 5+ or Cr 6+ , which leads to the inevitable non-radiative energy loss caused by energy transfer between ions, and ultimately leads to a decrease in luminescence efficiency, which limits its use in some fields. Secondly, the use of chromium may increase the risk of biological poisoning, especially when long-term in vivo use is required.

[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 object of the present invention is to provide a Cs2AgInCl6:xFe 3+ Infrared luminescent material, preparation method and application thereof. Among them, Cs2AgInCl6:xFe 3+ The infrared luminescent material has high chemical stability and an ultra-wide near-infrared emission band. In addition, the equipment required for the synthesis of the preparation method provided by the present invention is mature and simple, which is convenient for mass production.

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

[0006] A Cs2AgInCl6:xFe 3+Infrared luminescent material, its chemical formula is Cs2AgInCl6:xFe 3+ , 0≤x≤1.

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

[0008] In some preferred embodiments, Cs2AgInCl6:xFe 3+ The infrared luminescent material is obtained by solvent thermal reaction of cesium-containing compounds, silver-containing compounds, indium-containing compounds, chlorine-containing compounds and iron-containing compounds in an oxidizing atmosphere, wherein the temperature of the solvent thermal reaction is 150-200° C. and the insulation time of the solvent thermal 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 kind of Cs2AgInCl6:xFe 3+ The method for preparing an infrared luminescent material comprises the following steps:

[0011] Weigh 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. For 1 mmol of the silver-containing compound, 1 mmol of the indium-containing compound and x mol of the iron-containing compound (Fe 3+ ) compound, add 5mL of 12mol / L concentrated hydrochloric acid. Silver-containing compounds, indium-containing compounds, iron-containing compounds (Fe 3+ ) The compound and 5mL of concentrated hydrochloric acid are placed in a 20mL glass bottle and stirred at room temperature for 2 hours. Relative to 2mmol of the cesium-containing compound, 5mL of 12mol / L concentrated hydrochloric acid is added. The cesium-containing compound and 5mL of 12mol / L concentrated hydrochloric acid are placed in a 20mL glass bottle and shaken for 5 minutes to mix evenly. The two evenly mixed solutions are finally transferred to a polytetrafluoroethylene liner. Finally, a solvothermal reaction is carried out at a temperature of 150-200°C in an oxidizing atmosphere, kept warm for 5-18 hours, cooled to room temperature, the crystals are rinsed with anhydrous ethanol and dried to obtain the Cs2AgInCl6:xFe 3+ Infrared luminescent material.

[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 communications.

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

[0018] (1) Cs2AgInCl6:xFe 3+ Infrared luminescent materials have the unique characteristics of high chemical stability and can be effectively excited by 250-650 nanometer light to produce ultra-wide near-infrared luminescence. They can be used in near-infrared fluorescence imaging, optical fiber communication or anti-counterfeiting. 3+ As the luminescence center, the self-trapped exciton is not used as the luminescence center. 3+ The ion has a half-filled electronic structure (3d 5 ), so it can be presented 4 T1( 4 G) → 6 A1( 6 S) transition and emits near-infrared light.

[0019] (2) The preparation method provided by the present invention does not use high pressure and reductive harsh synthesis conditions, but adopts a solvothermal method and Cs2AgInCl6:xFe under normal pressure and oxidative atmosphere to prepare the 3+ The required chemical raw materials can be used to synthesize the luminescent materials. The preparation conditions are simple and can be mass-produced industrially. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 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 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 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 Cs2AgInCl6:xFe prepared in Example 1 3+ Emission spectra of infrared luminescent materials (x=0.2, 0.4, 0.6, 0.8, 1). DETAILED DESCRIPTION

[0024] The technical solution of the present invention is further illustrated and described below through specific implementation methods.

[0025] In the following examples, 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 examples are conventional detection methods; the reagents in the following examples are purchased from commercial channels unless otherwise specified.

[0026] Example 1

[0027] This embodiment provides a Cs2AgInCl6:xFe 3+ Infrared luminescent material and preparation method thereof, wherein x=0.2, 0.4, 0.6, 0.8, 1. In each compound raw material, 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] The preparation method thereof comprises the following steps:

[0029] Weigh 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. For 1 mmol of the silver-containing compound, 1 mmol of the indium-containing compound and x mol of the iron-containing compound (Fe 3+ ) compound, add 5mL of 12mol / L concentrated hydrochloric acid. Silver-containing compounds, indium-containing compounds, iron-containing compounds (Fe 3+) The compound and 5mL of concentrated hydrochloric acid were placed in a 20mL glass bottle and stirred at room temperature for 2 hours. For 2mmol of the cesium-containing compound, 5mL of 12mol / L concentrated hydrochloric acid was added. The cesium-containing compound and 5mL of 12mol / L concentrated hydrochloric acid were placed in a 20mL glass bottle and shaken for 5 minutes to mix evenly. The two evenly mixed solutions were finally transferred to a polytetrafluoroethylene liner. The reactor was placed in an oven, and in an air atmosphere, the temperature was increased from 25°C to 180°C at a heating rate of 3°C per minute, and maintained at 180°C for 12 hours. The sample was then cooled to room temperature at a cooling rate of 3°C per hour. Cs2AgInCl6:xFe was obtained by repeated washing with anhydrous ethanol and drying. 3+ Crystalline compound infrared luminescent material.

[0030] Figure 1 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). The spectra were collected using a Japanese Rigaku Smar / SmartLa X-ray diffractometer. During the spectrum collection, 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 Cs2AgInCl6 crystal structure (ICSD#1926611). Fe 3+ The doping does not introduce any impurities.

[0031] Figure 2 Cs2AgInCl6:xFe prepared in Example 1 3+ Diffuse reflectance spectra of infrared luminescent materials (x = 0.2, 0.4, 0.6, 0.8, 1). As can be seen from the figure, as Fe 3+ As the concentration increases, the sample's light absorption range increases, and the increase gradually decreases. Figure 2 It can be seen that Cs2AgInCl6:xFe 3+ The absorption range of infrared luminescent materials (x = 0.2, 0.4, 0.6, 0.8, 1) is 200-650 nanometers. This indicates that Fe 3+ It can exhibit excitable properties covering almost the entire visible light region in the Cs2AgInCl6 matrix.

[0032] Figure 3 Cs2AgInCl6:xFe prepared in Example 1 3+Excitation spectrum of infrared luminescent materials (x = 0.2, 0.4, 0.6, 0.8, 1). Monitoring the infrared wavelength of 1450 nanometers, the excitation spectrum of the sample covers from 250nm to about 700nm. In the excitation spectrum, the maximum excitation peaks are located at about 300nm and 400nm, respectively, which are attributed to the characteristic excitation of the Cs2AgInCl6 matrix and the characteristic excitation transition of the iron ion. When Fe 3+ When the amount of ion doping is small, the excitation of the matrix (300 nanometers) is dominant. 3+ As the ion doping content increases, the peak at 370 nm increases. 3+ When the concentration of ions is 0.4, the excitation intensity of the sample is the largest, indicating that Cs2AgInCl6:0.4Fe 3+ The sample has the best performance.

[0033] Figure 4 Cs2AgInCl6:xFe prepared in Example 1 3+ Photoemission spectra of infrared luminescent materials (x = 0.2, 0.4, 0.6, 0.8, 1). Figure 4 It can be seen that under 370 nm light excitation, Cs2AgInCl6:xFe 3+ The crystals with (x=0.2, 0.4, 0.6, 0.8, 1) can emit an ultra-wide emission band with a wavelength ranging from 800 nanometers to about 1600 nanometers. The emission spectrum is split into two peaks, with the maximum values ​​located near 1360 nanometers and 1420 nanometers, corresponding to different orbital electron transitions of iron ions. With the change of iron ion concentration, the emission peak intensity is slightly different. When the iron ion doping concentration is x=0.4, Cs2AgInCl6:0.4Fe 3+ The infrared emission of Cs2AgInCl6:0.4Fe 3+ Crystal has the best infrared luminescence performance.

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

Claims

1. A Cs2AgInCl6:xFe 3+ Infrared luminescent material, characterized in that Its general chemical formula is Cs2AgInCl6:xFe 3+ , 0≤x≤1.

2. Cs2AgInCl6:xFe according to claim 1 3+ Infrared luminescent material, characterized in that Its crystal structure is cubic and its space group is Fm-3m.

3. Cs2AgInCl6:xFe according to claim 1 or 2 3+ Infrared luminescent material, characterized in that The product is obtained by subjecting a cesium-containing compound, a silver-containing compound, an indium-containing compound, a chlorine-containing compound and an iron-containing compound to a solvent thermal reaction in an oxidizing atmosphere, wherein the temperature of the solvent thermal reaction is 150 to 200° C. and the insulation time of the solvent thermal reaction is 5 to 18 hours.

4. Cs2AgInCl6:xFe according to claim 3 3+ Infrared luminescent material, 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, 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.

5. Cs2AgInCl6:xFe according to any one of claims 1 to 4 3+ A method for preparing an infrared luminescent material, characterized in that: The following steps are involved: Weigh 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. For 1 mmol of the silver-containing compound, 1 mmol of the indium-containing compound and x mol of the iron-containing compound (Fe 3+ ) compound, add 5mL of 12mol / L concentrated hydrochloric acid. Silver compounds, indium compounds, iron (Fe 3+ ) The compound and 5mL of concentrated hydrochloric acid are placed in a 20mL glass bottle and stirred at room temperature for 2 hours. Relative to 2mmol of the cesium-containing compound, 5mL of 12mol / L concentrated hydrochloric acid is added. The cesium-containing compound and 5mL of 12mol / L concentrated hydrochloric acid are placed in a 20mL glass bottle and shaken for 5 minutes to mix evenly. The two evenly mixed solutions are finally transferred to a polytetrafluoroethylene liner. Finally, a solvothermal reaction is carried out at a temperature of 150-200°C in an oxidizing atmosphere, kept warm for 5-18 hours, cooled to room temperature, the crystals are rinsed with anhydrous ethanol and dried to obtain the Cs2AgInCl6:xFe 3+ Infrared luminescent material.

6. Cs2AgInCl6:xFe according to claim 5 3+ A method for preparing a luminescent material, characterized in that: The heating rate of the solvent thermal reaction is 2.5-5°C / min, and the cooling rate to room temperature is 3°C / h.

7. Cs2AgInCl6:xFe according to claim 5 3+ A method for preparing an infrared luminescent material, characterized in that: The oxidizing atmosphere is an oxygen atmosphere or an air atmosphere.

8. Cs2AgInCl6:xFe according to claim 5 3+ A method for preparing an infrared luminescent material, 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, 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.

9. Cs2AgInCl6:xFe according to any one of claims 1 to 4 3+ Application of infrared luminescent materials in near-infrared fluorescence imaging.

10. Cs2AgInCl6:xFe according to any one of claims 1 to 4 3+ Application of infrared luminescent materials in optical fiber communications.

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