An antimony-doped bismuth-based chlorine compound, preparation and application thereof

Abstract

The present invention discloses an antimony-doped bismuth-based chlorine compound, its preparation and application. The chemical formula of the bismuth-based chlorine compound is: Rb2CsBi (1‑x) Sb x Cl6, where x is the molar fraction, and its value range is 0

Description

Technical Field

[0001] The present invention relates to the technical field of luminescent materials, and more specifically to an antimony-doped bismuth-based chloride compound, its preparation and application. Background Art

[0002] Metal halide materials have good photoelectric properties and can be used to prepare devices such as light-emitting diodes, solar cells and photodetectors. 2 PbI 4 Tin dopants induce exciton self-trapping, resulting in significant red-near infrared light emission (Advanced Materials, 2019, 31, 7: 1806385). However, the toxicity of lead limits its large-scale use. On the basis of environmental friendliness and sustainable development, the use of non-toxic or low-toxic inorganic metal ions to replace lead is the development trend of metal halide materials. Therefore, high-efficiency non-lead inorganic metal halide luminescent materials have attracted the attention of researchers around the world. However, the reported Cs 3 BiCl 6 (Journal of Solid State Chemistry,1986,65,13-26), CsK 2 BiCl 6 (Journal of Solid State Chemistry(1986),65,13-26), Cs 3 Bi 2 Cl 9 (Zeitschrift fuer Anorganische und Allgemeine Chemie (1980), 468, 185-192) and other compounds have very weak luminescence properties.

[0003] So far, commercial metal halides with excellent luminescence properties have not appeared. On this basis, the exploration of new, non-toxic or low-toxic metal halide materials with excellent luminescence properties has attracted the attention of researchers. Summary of the invention

[0004] Based on the above defects, the first object of the present invention is to provide an antimony-doped bismuth-based chloride compound. The antimony-doped bismuth-based chloride compound provided by the present invention induces the occurrence of exciton self-trapping by replacing part of the bismuth ions with antimony ions, thereby producing efficient broadband yellow light emission, and can emit broadband strong yellow fluorescence with a wavelength of 400-800nm ​​under the excitation of ultraviolet light with a wavelength of 200-400nm, with a room temperature quantum yield of up to 45%, and the fluorescence effect is stronger at a low temperature of 237K after testing.

[0005] The second object of the present invention is to provide a method for preparing the above-mentioned antimony-doped bismuth-based chloride compound. The synthesis process of the present invention is simple, the reaction conditions are mild, the raw materials are rich in sources and low in price, the problems of lead toxicity and instability in lead-based halide crystals are solved, and it is expected to be widely used in the fields of optoelectronics and lighting.

[0006] The third object of the present invention is to provide an application of the above-mentioned antimony-doped bismuth-based chloride compound in the field of luminescent materials.

[0007] To achieve the above first object, the present invention adopts the following technical solutions:

[0008] The present invention discloses an antimony-doped bismuth-based chloride compound, and the chemical general formula of the bismuth-based chloride compound is: Rb 2 CsBi (1-x) Sb x Cl 6 , where x is the molar fraction, and its value range is 0 < x < 1; the bismuth-based chloride compound belongs to the orthorhombic crystal system, and the space group is Pbcm.

[0009] In the prior art, there are problems of lead toxicity and instability in the two-dimensional perovskite crystal PEA 2 PbI 4 , and the synthesis temperature of the Lu 3 Al 5 O 12 :Ce 3+ yellow phosphor is relatively high (greater than 1000 °C), and SrSi 2 O 2 N 2 :Eu requires inert gas protection, which all limit its large-scale use. Aiming at the problems of lead toxicity and instability in lead-based halide crystals in the prior art, as well as the problems of high synthesis temperature and easy oxidation under natural conditions of commercial yellow phosphors, the inventors designed an antimony-doped bismuth-based chloride compound, which can effectively solve the above problems. Colorless flake single crystals of bismuth-based chloride can be rapidly synthesized by hydrothermal reaction, the reaction conditions are mild, and under the doping of antimony, part of bismuth can be replaced, inducing the occurrence of exciton self-trapping, which is beneficial to the generation of efficient broadband yellow light emission. It has been found through research that this bismuth-based chloride compound can emit broadband strong yellow fluorescence with an emission wavelength in the range of 400 - 800 nm under ultraviolet light excitation with a wavelength of 200 - 400 nm, and the room temperature quantum yield is up to 45% at most. In addition, the decomposition temperature of this bismuth-based chloride compound is relatively high, and it shows good thermal stability below 600 °C. Therefore, it is expected to be widely used in the fields of optoelectronics and lighting.

[0010] To achieve the above second object, the present invention adopts the following technical solutions:

[0011] The present invention discloses a method for preparing the antimony-doped bismuth-based chloride compound as described above, comprising the following steps:

[0012] According to the chemical formula Rb 2 Cb (1-x) Sb x Cl 6 The stoichiometric ratio of each element in the mixture is adjusted, and a cesium-containing compound, a bismuth-containing compound, an antimony-containing compound and a rubidium-containing compound are weighed respectively, and a hydrogen chloride solution is added, and the mixture is placed in a hydrothermal reactor containing a polytetrafluoroethylene liner, and heated to 80-230° C., and kept warm for 0-30 hours for hydrothermal reaction, and then naturally cooled to room temperature, filtered, washed, and dried to obtain an antimony-doped bismuth-based chloride compound.

[0013] Furthermore, the hydrothermal reaction conditions are preferably 120°C for 2 hours. Under this condition, Rb 2 Cb (1-x) Sb x Cl 6 It can produce colorless flaky single crystals, reduce energy consumption and improve the safety of the preparation process.

[0014] Further, the rubidium-containing compound is one or more of an oxide, hydroxide, and chloride containing the corresponding ions, for example, it can be a combination of an oxide and a chloride, an oxide and a hydroxide, or a hydroxide and a chloride; the cesium-containing compound is one or more of an oxide, hydroxide, and chloride containing the corresponding ions, for example, it can be a combination of an oxide and a chloride, an oxide and a hydroxide, or a hydroxide and a chloride; the bismuth-containing compound is one or more of an oxide and a chloride containing the corresponding ions, for example, it can be a combination of an oxide and a chloride, an oxide and a hydroxide, or a hydroxide and a chloride. The antimony-containing compound is one of oxides and chlorides containing corresponding ions, or a combination thereof, such as a combination of oxides and chlorides, a combination of oxides and hydroxides, or a combination of hydroxides and chlorides; preferably, the rubidium-containing compound includes but is not limited to one or more of rubidium oxide, rubidium hydroxide or rubidium chloride, the cesium-containing compound includes but is not limited to one or more of cesium oxide, cesium hydroxide or cesium chloride, the bismuth-containing compound includes but is not limited to one or more of bismuth oxide, bismuth hydroxide or bismuth chloride, and the antimony-containing compound includes but is not limited to one or more of antimony oxide, antimony hydroxide or antimony chloride.

[0015] In a specific embodiment, in the hydrothermal reaction system, the molar ratio of the antimony-containing compound to the bismuth-containing compound should not be too large. When the molar ratio of the antimony-containing compound to the bismuth-containing compound exceeds 3:7, the crystal form of the final compound is affected, making it difficult to maintain the original Rb 2 CsBiCl6 The crystal structure will transform into other crystal phase structures and will no longer produce fluorescence effect.

[0016] Furthermore, the mass concentration of the hydrogen chloride solution is 20-38%.

[0017] Furthermore, the drying temperature is 30-50° C., and the drying time is 2-24 hours.

[0018] In order to achieve the third object, the present invention adopts the following technical solutions:

[0019] The present invention discloses an application of the antimony-doped bismuth-based chloride compound in the field of luminescent materials. The bismuth-based chloride compound is used as an electroluminescent material in a light-emitting diode or directly used as a phosphor.

[0020] Furthermore, the bismuth-based chloride compound has an emission wavelength of 400-800 nm under the excitation of ultraviolet light with a wavelength of 200-400 nm.

[0021] Furthermore, the bismuth-based chloride compound has a maximum quantum yield of 45% at room temperature, and further testing shows that the fluorescence effect is even stronger at a low temperature of 237K.

[0022] The beneficial effects of the present invention are as follows:

[0023] The present invention discloses an antimony-doped bismuth-based chlorine compound, which can effectively solve the problems of lead toxicity and instability in lead-based halide crystals in the prior art, as well as the high synthesis temperature of commercial yellow phosphors and easy oxidation under natural conditions. By doping with antimony, not only can the original Rb 2 CsBiCl 6 The crystal structure can also induce the occurrence of exciton self-trapping, resulting in efficient broadband yellow light emission. Under the excitation of ultraviolet light with a wavelength of 200-400nm, the emission wavelength is located at 400-800nm. The room temperature quantum yield is up to 45%. After further testing, the fluorescence effect is stronger at a low temperature of 237K. In addition, the antimony-doped bismuth-based chloride compound has good thermal stability below 600℃, indicating that it has excellent thermal stability and can be used as a luminescent material for electroluminescence in light-emitting diodes or directly used as a phosphor. In addition, the synthesis process provided by the present invention is simple, easy to operate, mild reaction conditions, abundant raw materials and low price, and is expected to achieve large-scale production and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings.

[0025] Figure 1 The bismuth-based chloride Rb prepared in Example 1 of the present invention is shown2 CsBiCl 6 , X-ray diffraction test patterns of antimony-doped bismuth-based chlorides prepared in Examples 2-7.

[0026] Figure 2 The bismuth-based chloride Rb prepared in Example 1 of the present invention is shown 2 CsBiCl 6 Thermogravimetric analysis results.

[0027] Figure 3 The bismuth-based chloride Rb prepared in Example 7 of the present invention is shown 2 Cb 0.965 Sb 0.035 Cl 6 Thermogravimetric analysis results.

[0028] Figure 4 The bismuth-based chloride Rb prepared in Example 1 of the present invention is shown 2 CsBiCl 6 , Antimony-doped bismuth-based chloride Rb prepared in Example 7 2 Cb 0.965 Sb 0.035 Cl 6 Fluorescence excitation spectrum at ultraviolet wavelength of 200-400nm.

[0029] Figure 5 The bismuth-based chloride Rb prepared in Example 1 of the present invention is shown 2 CsBiCl 6 , Fluorescence emission spectrum of antimony-doped bismuth-based chloride prepared in Example 2-7 at an ultraviolet wavelength of 378 nm.

[0030] Figure 6 The CIE chromaticity coordinate diagram obtained by calculating the emission spectrum of Example 7 of the present invention is shown.

[0031] Figure 7 The X-ray diffraction test spectrum of the sample prepared in Comparative Example 1 of the present invention is shown.

[0032] Figure 8 The fluorescence temperature-varying spectrum diagram of Example 7 of the present invention is shown. DETAILED DESCRIPTION

[0033] In order to more clearly illustrate the present invention, the present invention is further described below in conjunction with preferred embodiments and accompanying drawings. Similar components in the accompanying drawings are represented by the same reference numerals. It should be understood by those skilled in the art that the content specifically described below is illustrative rather than restrictive, and should not be used to limit the scope of protection of the present invention.

[0034] Example 1

[0035] 0.2418g of rubidium chloride, 0.1684g of cesium chloride, 0.2330g of bismuth trioxide, and 16ml of 38% aqueous hydrogen chloride solution were placed in a 50ml hydrothermal reactor lined with polytetrafluoroethylene, heated to 120°C, kept warm for 2h, cooled naturally to room temperature, filtered, washed, and dried in an oven at 30°C for 6h to obtain colorless flaky crystals of bismuth-based chloride with the chemical formula Rb 2 CsBiCl 6 .

[0036] According to single crystal diffraction test, bismuth-based chloride Rb 2 CsBiCl 6 It belongs to the orthorhombic system, the space group is Pbcm, and its structural parameters are shown in Table 1. The powder X-ray diffraction pattern is shown in Figure 1 , confirming that the bismuth-based chloride Rb 2 CsBiCl 6 single crystal form.

[0037] Thermogravimetric analysis Figure 2 Know that Rb 2 CsBiCl 6 It starts to decompose only when heated to 600℃, which proves that it has good thermal stability below 600℃ and has excellent thermal stability.

[0038] Table 1 Rb 2 CsBiCl 6 Structural parameters

[0039]

[0040] Example 2

[0041] 0.2418g of rubidium chloride, 0.1684g of cesium chloride, 0.2213g of bismuth trioxide, 0.0073g of antimony trioxide, and 16ml of 38% aqueous hydrogen chloride solution were placed in a 50ml hydrothermal reactor lined with polytetrafluoroethylene, heated to 120°C, kept warm for 2h, cooled naturally to room temperature, filtered, washed, and dried in an oven at 30°C for 6h to obtain antimony-doped bismuth-based chloride colorless flaky crystals. The chemical formula of the crystals was Rb as determined by SEM-EDX method. 2 Cb 0.997 Sb 0.003 Cl 6 .

[0042] After powder X-ray diffraction test, the X-ray diffraction pattern of the antimony-doped bismuth-based chloride prepared in Example 2 is as follows Figure 1 As shown, the crystal structure is consistent with that of Example 1, indicating that antimony doping does not affect its crystal structure.

[0043] Example 3

[0044] 0.2418g of rubidium chloride, 0.1684g of cesium chloride, 0.2097g of bismuth trioxide, 0.0146g of antimony trioxide, and 16ml of 38% aqueous hydrogen chloride solution were placed in a 50ml hydrothermal reactor lined with polytetrafluoroethylene, heated to 120°C, kept warm for 2h, cooled naturally to room temperature, filtered, washed, and dried in an oven at 30°C for 6h to obtain antimony-doped bismuth-based chloride colorless flaky crystals. The chemical formula tested by SEM-EDX method was Rb 2 Cb 0.99 Sb 0.01 Cl 6 .

[0045] After powder X-ray diffraction testing, the X-ray diffraction pattern of the antimony-doped bismuth-based chloride prepared in Example 3 is as follows: Figure 1 As shown, the crystal structure is consistent with that of Example 1, indicating that antimony doping does not affect its crystal structure.

[0046] Example 4

[0047] 0.2418g of rubidium chloride, 0.1684g of cesium chloride, 0.1980g of bismuth trioxide, 0.0219g of antimony trioxide, and 16ml of 38% aqueous hydrogen chloride solution were placed in a 50ml hydrothermal reactor lined with polytetrafluoroethylene, heated to 120°C, kept warm for 2h, cooled naturally to room temperature, filtered, washed, and dried in an oven at 30°C for 6h to obtain antimony-doped bismuth-based chloride colorless flaky crystals. The chemical formula tested by SEM-EDX method was Rb 2 Cb 0.984 Sb 0.016 Cl 6 .

[0048] After powder X-ray diffraction test, the X-ray diffraction pattern of the antimony-doped bismuth-based chloride prepared in Example 4 is as follows Figure 1 As shown, the crystal structure is consistent with that of Example 1, indicating that antimony doping does not affect its crystal structure.

[0049] Example 5

[0050] 0.2418g of rubidium chloride, 0.1684g of cesium chloride, 0.1864g of bismuth trioxide, 0.0292g of antimony trioxide, and 16ml of 38% aqueous hydrogen chloride solution were placed in a 50ml hydrothermal reactor lined with polytetrafluoroethylene, heated to 120°C, kept warm for 2h, cooled naturally to room temperature, filtered, washed, and dried in an oven at 30°C for 6h to obtain antimony-doped bismuth-based chloride colorless flaky crystals. The chemical formula tested by SEM-EDX method was Rb 2 Cb 0.981 Sb 0.019 Cl6 .

[0051] After powder X-ray diffraction test, the X-ray diffraction pattern of the antimony-doped bismuth-based chloride prepared in Example 5 is as follows: Figure 1 As shown, the crystal structure is consistent with that of Example 1, indicating that antimony doping does not affect its crystal structure.

[0052] Example 6

[0053] 0.2418g of rubidium chloride, 0.1684g of cesium chloride, 0.1747g of bismuth trioxide, 0.0364g of antimony trioxide, and 16ml of 38% aqueous hydrogen chloride solution were placed in a 50ml hydrothermal reactor lined with polytetrafluoroethylene, heated to 120°C, kept warm for 2h, cooled naturally to room temperature, filtered, washed, and dried in an oven at 30°C for 6h to obtain antimony-doped bismuth-based chloride colorless flaky crystals. The chemical formula tested by SEM-EDX method was Rb 2 Cb 0.978 Sb 0.022 Cl 6 .

[0054] After powder X-ray diffraction testing, the X-ray diffraction pattern of the antimony-doped bismuth-based chloride prepared in Example 6 is as follows: Figure 1 As shown, the crystal structure is consistent with that of Example 1, indicating that antimony doping does not affect its crystal structure.

[0055] Example 7

[0056] 0.2418g of rubidium chloride, 0.1684g of cesium chloride, 0.1631g of bismuth trioxide, 0.0437g of antimony trioxide, and 16ml of 38% aqueous hydrogen chloride solution were placed in a 50ml hydrothermal reactor lined with polytetrafluoroethylene, heated to 120°C, kept warm for 2h, cooled naturally to room temperature, filtered, washed, and dried in an oven at 30°C for 6h to obtain antimony-doped bismuth-based chloride colorless flaky crystals. The chemical formula tested by SEM-EDX method was Rb 2 Cb 0.965 Sb 0.035 Cl 6 , with a room temperature quantum yield of 45%.

[0057] After powder X-ray diffraction testing, the X-ray diffraction pattern of the antimony-doped bismuth-based chloride prepared in Example 7 is as follows: Figure 1 As shown, the crystal structure is consistent with that of Example 1, indicating that antimony doping does not affect its crystal structure.

[0058] Thermogravimetric analysis Figure 3 Know that Rb 2 CsBiCl 6It starts to decompose only when heated to 600℃, which proves that it has good thermal stability below 600℃ and has excellent thermal stability.

[0059] Comparative Example 1

[0060] 0.2418g of rubidium chloride, 0.1684g of cesium chloride, 0.1165g of bismuth trioxide, 0.0729g of antimony trioxide, and 16ml of 38% aqueous hydrogen chloride solution were placed in a 50ml hydrothermal reactor lined with polytetrafluoroethylene, heated to 120°C, kept warm for 2h, cooled naturally to room temperature, filtered, washed, and dried in an oven at 30°C for 6h to obtain a comparative sample. The sample was tested by powder X-ray diffraction and found to have Figure 7 As shown, the diffraction peak position and intensity are similar to those of Rb 2 CsBiCl 6 The diffraction peaks of the standard card are inconsistent, indicating that the crystal structure of the sample in Comparative Example 1 has changed, and the fluorescence test found that there is no fluorescence effect.

[0061] Test Example 1

[0062] The samples of Example 1 and Example 7 were excited by ultraviolet light with a wavelength of 200-400 nm. The results are shown in Figure 4 , the fluorescence spectrum test analysis shows that the Rb prepared in Example 1 2 CsBiCl 6 The fluorescence is very weak, while the Rb prepared in Example 7 2 Cb 0.965 Sb 0.035 Cl 6 It exhibits strong yellow fluorescence, and its intensity is maximum at the ultraviolet wavelength of 378nm.

[0063] Then, the samples prepared in Example 1-7 were subjected to fluorescence spectrum test, and the ultraviolet wavelength was 378nm. Figure 5 It can be seen that the samples prepared in Examples 2-7 exhibit yellow fluorescence of different intensities under the excitation of ultraviolet light with a wavelength of 378nm. The fluorescence intensity increases with the increase of antimony doping, and Figure 6 From the CIE chromaticity coordinate diagram, it is known that its color coordinates are (0.44, 0.51), that is, without changing the crystal structure, the excitation spectrum range and emission intensity of the sample are significantly improved by doping with antimony.

[0064] Test Example 2

[0065] The sample of Example 7 was subjected to a fluorescence temperature test, and the fluorescence was tested when the temperature dropped from 297K to 77K and when the temperature rose from 297K to 397K. The results are shown in Figure 8In the temperature range of 77K-397K, the sample has an inflection point at 237K, with the maximum fluorescence intensity, which is significantly higher than the fluorescence intensity at room temperature (297K).

[0066] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. An antimony-doped bismuth-based chloride compound, It is characterized in that The chemical general formula of the bismuth-based chloride compound is: Rb 2 CsBi (1-x) Sb x Cl 6 , where x is the mole fraction and its value range is 0 < x < 1; the bismuth-based chloride compound belongs to the orthorhombic crystal system and the space group is Pbcm.

2. A method for preparing the bismuth-based chloride compound as claimed in claim 1, It is characterized in that The steps include: According to the chemical formula Rb 2 Cb (1-x) Sb x Cl 6 The stoichiometric ratio of each element in the mixture is adjusted, and a cesium-containing compound, a bismuth-containing compound, an antimony-containing compound and a rubidium-containing compound are weighed respectively, and a hydrogen chloride solution is added, and the mixture is placed in a hydrothermal reactor containing a polytetrafluoroethylene liner, and heated to 80-230° C., and kept warm for 0-30 hours for hydrothermal reaction, and then naturally cooled to room temperature, filtered, washed, and dried to obtain an antimony-doped bismuth-based chloride compound.

3. The preparation method according to claim 2, It is characterized in that The hydrothermal reaction conditions are: a hydrothermal temperature of 120° C. and a heat preservation time of 2 h.

4. The preparation method according to claim 2, It is characterized in that The rubidium-containing compound is one or more of oxides, hydroxides, and chlorides containing corresponding ions; the cesium-containing compound is one or more of oxides, hydroxides, and chlorides containing corresponding ions; the bismuth-containing compound is one or more of oxides, hydroxides, and chlorides containing corresponding ions; and the antimony-containing compound is one or more of oxides, hydroxides, and chlorides containing corresponding ions.

5. The preparation method according to claim 4, It is characterized in that The rubidium-containing compound is selected from one or more of rubidium oxide, rubidium hydroxide or rubidium chloride, the cesium-containing compound is selected from one or more of cesium oxide, cesium hydroxide or cesium chloride, the bismuth-containing compound is selected from one or more of bismuth oxide, bismuth hydroxide or bismuth chloride, and the antimony-containing compound is selected from one or more of antimony oxide, antimony hydroxide or antimony chloride.

6. The preparation method according to claim 2, It is characterized in that The mass concentration of the hydrogen chloride solution is 20-38%.

7. The preparation method according to claim 2, It is characterized in that The drying temperature is 30-50℃ and the drying time is 2-24h.

8. Use of the bismuth-based chloride compound as claimed in claim 1 in the field of luminescent materials, It is characterized in that The bismuth-based chloride compound is used as an electroluminescent material in a light-emitting diode or directly as a phosphor.

9. The use according to claim 8, It is characterized in that The bismuth-based chloride compound has an emission wavelength of 400-800 nm under the excitation of ultraviolet light with a wavelength of 200-400 nm.

10. The use according to claim 8, It is characterized in that The bismuth-based chloride compound has a quantum yield of up to 45% at room temperature.

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