Water-resistant organic-inorganic hybrid cuprous halide luminescent material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of new materials, and particularly relates to an organic-inorganic hybrid cuprous halide luminescent material and a preparation method and application thereof. Through a solvothermal method, triphenylphosphine and copper-containing halide are dissolved in a mixed solvent at a high temperature, and the organic-inorganic hybrid cuprous halide luminescent material is obtained through natural cooling to room temperature and recrystallization crystallization. The luminescent material is a needle-like micron-sized crystal, the chemical formula is (C18H15P) 3Cu2Br2, the luminescent material has good luminescence performance, high temperature sensitivity and excellent water stability, the temperature sensing relative sensitivity of the luminescent material can reach 12.8% K <-1 >, and the luminescent material is expected to serve as a new-generation optical temperature sensing material and is applied to real life with high humidity.

Description

Technical Field

[0001] The present invention specifically relates to a water-resistant organic-inorganic hybrid cuprous halide luminescent material, a preparation method thereof and an application thereof, belonging to the technical field of nano-luminescent materials. Background Art

[0002] Temperature is one of the most important physical parameters in natural processes, and accurate temperature measurement is of great significance. Traditional contact thermometers are limited by technology and difficult to measure the temperature of nano- and sub-micron-sized objects or fast-moving objects. Among various temperature measurement methods, optical temperature sensing realizes temperature monitoring by monitoring the response relationship between optical parameters (such as fluorescence intensity, fluorescence intensity ratio, emission full width at half maximum, peak position and fluorescence lifetime) and temperature changes, and has advantages such as non-invasiveness, fast response, high accuracy and anti-electromagnetic interference, which has attracted wide attention in the academic and industrial fields. Among them, the development of optical temperature measurement materials is the top priority of optical temperature sensing.

[0003] In recent years, metal halides have stood out from many optical temperature measurement materials due to their diverse temperature-dependent luminescence characteristics. On the one hand, metal halides can achieve temperature sensing based on their nanosecond-level fluorescence lifetime by doping ns 2 configuration ions with temperature sensitivity. On the other hand, metal halides can also form organic-inorganic hybrid metal halides by hybridizing with organic components, and then have significant structural temperature sensitivity. At high temperatures, the thermal motion of organic molecules intensifies, causing the unit cell to expand sharply, breaking the regular lattice structure and inducing the formation of crystal defects. These defects affect the luminescence characteristics of self-trapped excitons, making their fluorescence lifetime sensitive to temperature changes and becoming a temperature response parameter, thereby realizing the sensing and monitoring of temperature. Chinese Patent CN119331613A discloses a temperature sensing material based on dual-mode thermoresponsive upconversion luminescence, a preparation method thereof and an application thereof. The chemical formula of the material is Bi 4y Ti 0.5 M 0.5 O8X:RE y ; wherein, M is W or Mo, X is Cl or Br, RE is Er or Yb / Er, and a hydrothermal molten salt method serial synthesis strategy is adopted for preparation; different from traditional thermal quenching materials, the temperature sensing material Bi4Ti 0.5 M 0.5For O8X, as the temperature increases, the visible light weakens while the near-infrared emission at 800 nm also enhances. It has a high optical temperature sensitivity in both fluorescence intensity mode and fluorescence lifetime mode, and is an optical temperature sensing material with a wide temperature measurement range that can be used for high-temperature environment detection, showing great application potential in the field of optical temperature sensing. Chinese Patent CN109943329A discloses a two-dimensional mixed-metal halide luminescent semiconductor with the molecular formula [(Me)2DABCO]Ag2PbBr6, belonging to the monoclinic system and the P21 space group. This mixed-metal halide can emit red light with a wavelength of 711 nm under the excitation of ultraviolet light with a wavelength of 316 nm, and the luminescence intensity shows a linear relationship with temperature within 80 - 200 K, making it a fluorescent temperature sensing material for the low-temperature region.

[0004] It can be seen that metal halides have become an ideal choice for preparing optical temperature measurement materials. However, the intrinsic property of metal halides is that they are ionic crystals, and each component is combined through charge attraction and polyhedral coordination, which has the inherent problem of poor stability - especially poor water stability. Restricted by these problems, existing metal halides are difficult to be applied in high-humidity environments. Currently, in the field of developing metal halides with both high water stability and high optical temperature sensing performance, there is still a blank. Therefore, it is urgent to develop new metal halides with good water stability to meet the actual needs of existing temperature sensing. Summary of the Invention

[0005] Aiming at the existing problems, the present invention provides a water-resistant organic-inorganic hybrid cuprous halide luminescent material, its preparation method and application. This luminescent material has both good luminescence and high temperature sensitivity. The fluorescence lifetime and intensity are sensitive to temperature changes. By monitoring the fluorescence lifetime or intensity of this material, optical temperature sensing is expected to be achieved. In addition, this luminescent material also has excellent water stability, which enables it to be widely applied to various high-humidity production and living scenarios.

[0006] The technical solution of the present invention is as follows:

[0007] The present invention provides a water-resistant organic-inorganic hybrid cuprous halide luminescent material, and the chemical formula of the luminescent material is: (C 18 H 15 P)3Cu2Br2.

[0008] Furthermore, the luminescent material is needle-shaped micron-sized crystals.

[0009] Furthermore, the space group of the luminescent material is P21 / n, and its unit cell parameters are: α = 90°, β = 109.8°, γ = 90°.

[0010] The above-mentioned water-resistant organic-inorganic hybrid cuprous halide luminescent material provided by the present invention can emit green fluorescence in the visible light range of 420-700 nm under the excitation of light with a wavelength of 250-400 nm, the emission peak is between 500-600 nm, the fluorescence quantum yield is greater than 40%, and it has good luminescence performance. The lifetime and light intensity of the emitted fluorescence are sensitive to temperature changes.

[0011] The present invention also provides a preparation method of the above-mentioned water-resistant organic-inorganic hybrid cuprous halide luminescent material, which includes the following steps:

[0012] S1. Mix cuprous bromide and triphenylphosphonium bromide, and then fully disperse the obtained mixture in a solvent to obtain a mixture dispersion;

[0013] S2. Heat and stir the mixture dispersion obtained in step S1 until the mixture is completely dissolved and continue stirring for 0-60 min to obtain a clear and transparent solution;

[0014] S3. Stop heating the solution obtained in step S2, naturally cool it to room temperature, and recrystallize to precipitate crystals; the obtained crystals are washed with an organic solvent and dried to obtain the water-resistant organic-inorganic hybrid cuprous halide luminescent material.

[0015] Further, in step S1, the solvent is a mixed solvent of N,N-dimethylformamide and hypophosphorous acid with a volume ratio of (4-6):1.

[0016] Further, in step S1, the molar ratio of cuprous bromide to triphenylphosphonium bromide is 1:(0.25-2).

[0017] Further, in step S2, the temperature for heating and stirring the mixture dispersion is 80-120 °C.

[0018] Further, in step S3, the organic solvent for washing is ethanol or isopropanol; the drying temperature is 30-80 °C.

[0019] The water-resistant organic-inorganic hybrid cuprous halide luminescent material provided by the present invention can be applied to the field of optical temperature sensing.

[0020] Different from the prior art, the present invention has the following beneficial effects:

[0021] 1. The present invention provides a water-resistant organic-inorganic hybrid cuprous halide luminescent material, which is a needle-shaped micron-sized crystal, with both good luminescence and high temperature sensitivity. Under the excitation of light with a wavelength of 250-400 nm, it can emit green fluorescence in the visible light range of 420-700 nm. The lifetime and light intensity of the fluorescence are sensitive to temperature changes, and the relative sensitivity of its temperature sensing can reach up to 12.8% K -1, which is the highest value of non-doped luminescent metal halides. Therefore, it has broad application prospects in the field of optical temperature sensing.

[0022] 2. Compared with the existing halide luminescent materials, the water-resistant organic-inorganic hybrid cuprous halide luminescent material provided by the present invention also has good water stability. The chemical formula of the luminescent material of the present invention is (C 18 H 15 P)3Cu2Br2. The presence of the triphenylphosphine structure in the chemical structure makes the luminescent material have strong hydrophobicity. At the same time, triphenylphosphine is also connected to Cu by a covalent bond, and the connection of the covalent bond further improves the water stability of the chemical structure of the luminescent material. Therefore, the above characteristics enable the luminescent material synthesized by the present invention to overcome the inherent defect of poor water stability of the existing halide luminescent materials, and can still maintain more than 87% of the luminescence intensity after being soaked in water for 30 days, and can be applied to temperature monitoring and sensing in various high-humidity environments.

[0023] 3. The present invention dissolves triphenylphosphine and cuprous halide in a mixed solvent at a relatively high temperature by a solvothermal method, and obtains the luminescent material by natural cooling to room temperature and recrystallization and crystallization. The reaction raw materials of this preparation method can be directly purchased from reagent companies without further purification, which can effectively reduce the preparation cost, the process is simple, the cost is low and the repeatability is extremely high, which is convenient for large-scale preparation and industrial application. Brief Description of the Drawings

[0024] Figure 1 It is the structural framework diagram of the product obtained in Example 1 of the present invention.

[0025] Figure 2 It is the powder X-ray diffraction spectrum of the product obtained in Example 1 of the present invention.

[0026] Figure 3 It is the relevant X-ray photoelectron spectroscopy (XPS) of the product obtained in Example 1 of the present invention.

[0027] Figure 4 It is the scanning electron microscope image and element distribution map of the product obtained in Example 1 of the present invention.

[0028] Figure 5 It is the excitation and emission spectrum of the product obtained in Example 1 of the present invention; solid line: emission spectrum (excitation wavelength is 355 nm); dotted line: excitation spectrum (emission wavelength is 524 nm).

[0029] Figure 6 It is the thermogravimetric spectrum of the product obtained in Example 1 of the present invention.

[0030] Figure 7 It is the variable-temperature spectrum of the product obtained in Example 1 of the present invention.

[0031] Figure 8 Powder X-ray diffraction patterns of the product obtained in Example 1 of the present invention after being placed in water for 0, 10, 20, and 30 days.

[0032] Figure 9 Variation of the luminescence intensity of the product obtained in Example 1 of the present invention after being placed in water for 0, 1, 2, 3, 5, 7, 10, 15, 20, 25, and 30 days.

[0033] Figure 10 Variable-temperature powder X-ray diffraction pattern of the product obtained in Example 1 of the present invention.

[0034] Figure 11 Graph of the fluorescence lifetime of the product obtained in Example 1 of the present invention varying with temperature.

[0035] Figure 12 Graph of the relative temperature sensing sensitivity of the product obtained in Example 1 of the present invention.

[0036] Figure 13 Graph of the change of the fluorescence lifetime of the product obtained in Example 1 of the present invention with the soaking time in hot water. Detailed implementation manners

[0037] The present invention will be further described below in conjunction with the accompanying drawings and preferred embodiments. The provided embodiments are only for clarifying the present invention and not for limiting the scope of the present invention.

[0038] The materials, reagents, etc. used in the following embodiments can be obtained from commercial channels without special instructions; the methods in the following embodiments are conventional methods without special instructions.

[0039] The present invention provides a water-resistant organic-inorganic hybrid cuprous halide luminescent material, and the chemical formula of the luminescent material is: (C 18 H 15 P)3Cu2Br2; the luminescent material is needle-shaped micron-sized crystals; the space group of the luminescent material is P21 / n, and its unit cell parameters are: α = 90°, β = 109.8°, γ = 90°.

[0040] The present invention also provides a preparation method of the above-mentioned water-resistant organic-inorganic hybrid cuprous halide luminescent material, including the following steps:

[0041] S1. Mix cuprous bromide and triphenylphosphine bromide, and then fully disperse the obtained mixture in a solvent to obtain a mixture dispersion.

[0042] S2. Heat and stir the mixture dispersion obtained in step S1 until the mixture is completely dissolved and then continuously stir and react for 0 - 60 min to obtain a clear and transparent solution;

[0043] S3. Stop heating the solution obtained in step S2, naturally cool it to room temperature, and recrystallize to precipitate crystals; the obtained crystals are washed with an organic solvent and dried to obtain the water - resistant organic - inorganic hybrid cuprous halide luminescent material.

[0044] In some embodiments, in step S1, the solvent can be a mixed solvent of N,N - dimethylformamide and hypophosphorous acid with a volume ratio of (4 - 6):1.

[0045] In some embodiments, in step S1, the molar ratio of cuprous bromide to triphenylphosphine bromide can be 1:(0.25 - 2).

[0046] In some embodiments, in step S2, the temperature for heating and stirring the mixture dispersion is 80 - 120 °C, preferably 90 - 110 °C.

[0047] In some embodiments, in step S3, the organic solvent for washing can be ethanol or isopropanol, preferably isopropanol; the drying temperature is 30 - 80 °C, preferably 50 - 80 °C; the drying method can be conventional drying or vacuum drying, preferably vacuum drying.

[0048] The water - resistant organic - inorganic hybrid cuprous halide luminescent material provided by the present invention can be applied to the field of optical temperature sensing.

[0049] The following further illustrates the water - resistant organic - inorganic hybrid cuprous halide luminescent material, its preparation method and application of the present invention with specific examples:

[0050] The instrument model used for the powder X - ray diffraction test (XRD) involved in the following examples is MiniFlex600, the manufacturer is Rigaku, and the copper target radiation wavelength is λ = 0.154187 nm.

[0051] The instrument model used for the X - ray photoelectron spectroscopy (XPS) analysis carried out in the following examples is ESCALAB 250Xi, the manufacturer is Thermo Fisher.

[0052] The instrument model used for the emission spectrum characterization carried out in the following examples is FLS980, the manufacturer is Edinburgh, the excitation light source is a xenon lamp, the excitation wavelength is 355 nm, and the monitoring wavelength is 524 nm.

[0053] Example 1

[0054] This embodiment provides a method for preparing a water-resistant organic-inorganic hybrid cuprous halide luminescent material, which includes the following steps:

[0055] S1. Mix 2 mmol of cuprous bromide (CuBr) powder and 1 mmol of triphenylphosphine bromide (C 18 H 16 PBr) powder in a 50 mL single-necked flask, add a mixed solution composed of 4 mL of N,N-dimethylformamide and 1 mL of hypophosphorous acid thereto, and disperse the mixture evenly in the mixed solution to obtain a mixture dispersion;

[0056] S2. Heat and stir the mixture dispersion obtained in step S1 to 95 °C to completely dissolve the mixture, and then continuously stir and react at 95 °C for 15 min to obtain a clear and transparent solution;

[0057] S3. Stop heating the solution obtained in step S2, naturally cool it to room temperature, and recrystallize to precipitate crystals; the obtained crystals are washed with isopropanol and dried in vacuum at 60 °C to obtain the water-resistant organic-inorganic hybrid cuprous halide luminescent material.

[0058] The chemical formula of the water-resistant organic-inorganic hybrid cuprous halide luminescent material prepared by the above preparation method is: (C 18 H 15 P)3Cu2Br2, and its structural framework diagram is as Figure 1 shown; the luminescent material is needle-shaped micron-sized crystals; as Figure 2 shown, the space group of this luminescent material is P21 / n, and its unit cell parameters are: α = 90°, β = 109.8°, γ = 90°, and the diffraction peak positions and relative intensities are all consistent with the XRD diffraction pattern theoretically simulated according to its single crystal data( Figure 2 ), which confirms that the sample obtained in this embodiment is a pure phase. As Figure 3 shown, the XPS characterization results of this luminescent material show that elements C, P, Cu, and Br are distributed on the material surface. As Figure 4 shown, each element is evenly distributed on the needle-shaped surface of the material.

[0059] Example 2

[0060] This embodiment provides a method for preparing a water-resistant organic-inorganic hybrid cuprous halide luminescent material, which includes the following steps:

[0061] S1. Mix 4 mmol of cuprous bromide (CuBr) powder and 1 mmol of triphenylphosphine bromide (C 18 H 16The (C

[0062] S2. Heat and stir the mixture dispersion obtained in step S1 to 80 °C until the mixture is completely dissolved, and then continuously stir and react at 80 °C for 60 min to obtain a clear and transparent solution;

[0063] S3. Stop heating the solution obtained in step S2, naturally cool it to room temperature, and recrystallize to precipitate crystals; the obtained crystals are washed with ethanol and dried in vacuum at 30 °C to obtain the water-resistant organic-inorganic hybrid cuprous halide luminescent material.

[0064] The water-resistant organic-inorganic hybrid cuprous halide luminescent material prepared by the above preparation method has the chemical formula: (C 18 H 15 P)3Cu2Br2, which has the same needle-like morphology and crystal structure as in Example 1.

[0065] Example 3

[0066] This example provides a preparation method of a water-resistant organic-inorganic hybrid cuprous halide luminescent material, including the following steps:

[0067] S1. Mix 0.5 mmol of cuprous bromide (CuBr) powder and 1 mmol of triphenylphosphine bromide (C 18 H 16 PBr) powder in a 50 mL single-necked flask, add a mixed solution composed of 5 mL of N,N-dimethylformamide and 1 mL of hypophosphorous acid thereto, and disperse the mixture evenly in the mixed solution to obtain a mixture dispersion;

[0068] S2. Heat and stir the mixture dispersion obtained in step S1 to 120 °C until the mixture is completely dissolved to obtain a clear and transparent solution;

[0069] S3. Stop heating the solution obtained in step S2, naturally cool it to room temperature, and recrystallize to precipitate crystals; the obtained crystals are washed with ethanol and dried in vacuum at 80 °C to obtain the water-resistant organic-inorganic hybrid cuprous halide luminescent material.

[0070] The water-resistant organic-inorganic hybrid cuprous halide luminescent material prepared by the above preparation method has the chemical formula: (C 18 H 15 P)3Cu2Br2, which has the same needle-like morphology and crystal structure as in Example 1.

[0071] Performance Test

[0072] The samples prepared by the preparation method described in Example 1 above were selected for stability and optical temperature sensing performance tests:

[0073] As Figure 6 shown, thermogravimetric analysis was performed on the water-resistant organic-inorganic hybrid cuprous halide luminescent material of Example 1. The results showed that its initial decomposition temperature was 230 °C, indicating that it had high thermal stability.

[0074] Under ambient conditions, variable-temperature spectroscopy tests were performed on the samples, and the data obtained were as Figure 7 shown. The quenching phenomenon of the samples was obvious as the temperature increased, indicating that they had high temperature sensitivity performance.

[0075] As Figure 8 shown, no phase change occurred after the samples were soaked in water for 30 days, indicating that the samples had good structural water stability.

[0076] As Figure 9 shown, the samples could still maintain 87% of the luminescence intensity after being soaked in water for 30 days, indicating that the luminescence of the samples had excellent water stability.

[0077] As Figure 10 shown, in the temperature range from room temperature to 380 K, no phase change occurred in the samples, and the peak position significantly shifted to a small angle, which represented obvious expansion of the lattice, indicating that the samples had both excellent stability and the characteristics of a soft lattice and had the potential for temperature sensing.

[0078] As the temperature increased, due to the soft lattice characteristics of the material and the enhanced vibration of organic molecules with increasing temperature, fluorescence quenching was severe. As Figure 11 shown, its fluorescence lifetime decreased from 51.3 μs at 280 K to 0.97 μs at 380 K, only 1.9% of the initial value. Such a large change amplitude made it very suitable for non-contact fluorescence temperature sensing.

[0079] According to Figure 11 the results, the relative sensitivity curve of temperature sensing of the samples was obtained by fitting. As Figure 12 shown, the maximum value of the relative sensitivity was 12.8% at 380 K, indicating that the samples had excellent temperature sensing performance. The relative sensitivity was calculated by the following formula:

[0080]

[0081] In the formula, S r represents the relative sensitivity, T represents the temperature (K), and τ represents the fluorescence lifetime.

[0082] Figure 13It is a graph showing the change of the fluorescence lifetime of the sample with the immersion time in hot water. The results show that the sample can achieve temperature sensing in hot water, which further indicates that the sample can be applied to the vast majority of practical application scenarios and has outstanding practicality.

[0083] In summary, the water-resistant organic-inorganic hybrid cuprous halide luminescent material provided by the present invention has good luminescence, high temperature sensitivity, excellent thermal stability and water stability. The fluorescence lifetime and intensity of the material are sensitive to temperature changes. By monitoring the fluorescence lifetime or intensity of the material, it is expected to achieve optical temperature sensing, which can be widely applied to various production and living scenarios with high humidity.

[0084] The specific embodiments of the present invention have been exemplarily described above through examples. However, the protection scope of the present invention is not limited to the above exemplary embodiments. Any modifications, equivalent substitutions, improvements, etc. made by those skilled in the art within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. A water-resistant organic-inorganic hybrid cuprous halide luminescent material, characterized in that: The chemical formula of the luminescent material is: 18 H 15 P)3Cu2Br2.

2. The water-resistant organic-inorganic hybrid cuprous halide luminescent material according to claim 1, characterized in that: The luminescent material is a needle-shaped micron-sized crystal; the space group of the luminescent material is P21 / n, and its unit cell parameters are: α=90°, β=109.8°, γ=90°.

3. A method for preparing a water-resistant organic-inorganic hybrid cuprous halide luminescent material as claimed in claim 1 or 2, characterized in that: The steps include: S1, mixing cuprous bromide and triphenylphosphine bromide, and then fully dispersing the obtained mixture in a solvent to obtain a mixture dispersion; S2, heating and stirring the mixture dispersion obtained in step S1 until the mixture is completely dissolved and continuing to stir and react for 0 to 60 minutes to obtain a clear and transparent solution; S3, stopping heating the solution obtained in step S2, cooling it naturally to room temperature, and recrystallizing to precipitate crystals; washing the obtained crystals with an organic solvent and drying them to obtain the water-resistant organic-inorganic hybrid cuprous halide luminescent material.

4. The method for preparing the water-resistant organic-inorganic hybrid cuprous halide luminescent material according to claim 3, characterized in that: In step S1, the solvent is a mixed solvent of N,N-dimethylformamide and hypophosphorous acid in a volume ratio of (4-6):

1.

5. The method for preparing the water-resistant organic-inorganic hybrid cuprous halide luminescent material according to claim 3, characterized in that: In step S1, the molar ratio of cuprous bromide to triphenylphosphine bromide is 1:(0.25-2).

6. The method for preparing the water-resistant organic-inorganic hybrid cuprous halide luminescent material according to claim 3, characterized in that: In step S2, the temperature of heating and stirring the mixture dispersion is 80-120°C.

7. The preparation method according to claim 3, characterized in that: In step S3, the organic solvent used for washing is ethanol or isopropanol; and the drying temperature is 30-80°C.

8. Applying the water-resistant organic-inorganic hybrid cuprous halide luminescent material as claimed in claim 1 or 2 to the field of optical temperature sensing.

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