Ytterbium-doped perovskite quantum dot material and preparation method and application thereof

Abstract

The invention belongs to the technical field of luminescent materials, and particularly relates to an ytterbium-doped perovskite quantum dot material and a preparation method and application thereof. According to the ytterbium-doped perovskite quantum dot material provided by the invention, Al ions are trivalent, the radius of the Al ions is much smaller than that of Pb ions, the capacity of occupying a Pb site is relatively weak, and an obvious competitive relationship is not formed when the Al ions are co-doped with Yb because the radius of the Al ions is relatively small, so that the Al ions cannot stably occupy the Pb vacancy, and a new Pb vacancy is easily generated under separation in a high-temperature environment; according to the Al / Yb doped CsPbCl3 quantum dot, the probability that Yb enters a Pb site again is increased, the actual doping concentration of Yb is improved, a band gap influencing transmission of a host to Yb energy level electrons is not introduced, the near-infrared light emitting efficiency of the Al / Yb doped CsPbCl3 quantum dot is improved, and meanwhile, the storage stability of the product can be improved through auxiliary doping of Al.

Description

Technical Field

[0001] The present invention belongs to the technical field of luminescent materials, and particularly relates to a ytterbium-doped perovskite quantum dot material, a preparation method thereof, and an application thereof. Background Art

[0002] In recent years, the research investment in the field of solar photovoltaic power generation in China has increased significantly. In order to improve the photoelectric conversion efficiency, researchers have applied light conversion materials to battery components, so as to convert the light band with low utilization rate of the battery components to the band with high utilization rate.

[0003] Due to the quantum dot tailoring effect, ytterbium (Yb)-doped lead halide perovskite quantum dots can theoretically achieve a near-infrared luminescence efficiency of more than 100%, and are ideal materials for photovoltaic gain. However, due to the valence mismatch between trivalent Yb ions and divalent Pb ions in the octahedron, the actual doping concentration of Yb is low, the near-infrared luminescence efficiency is low, and the storage stability of the sample is poor, which greatly affects the further application prospects of quantum-tailored near-infrared luminescent materials in the field of photovoltaic power generation. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defects in the prior art, such as low Yb ion concentration, low near-infrared luminescence efficiency, and poor storage stability of the sample in Yb-doped CsPbCl3 quantum dots, so as to provide a ytterbium-doped perovskite quantum dot material, a preparation method thereof, and an application thereof.

[0005] For this purpose, the present invention provides the following technical solutions:

[0006] The present invention provides a ytterbium-doped perovskite quantum dot material, and the structural formula composition is: CsAl m Yb n Pb (1-m-n) Cl x Br (3-x) , where the value range of x is 0.8 to 3, 0 < m ≤ 0.1, and 0 < n ≤ 0.1.

[0007] Optionally, the value range of x is 2 to 3, the value range of m is 0.001 to 0.05, and the value range of n is 0.005 to 0.1.

[0008] The present invention also provides a preparation method of the above-mentioned ytterbium-doped perovskite quantum dot material, including the following steps:

[0009] S1, obtaining a lead source, a cesium source, a halogen source, an aluminum source, and a ytterbium source required for synthesizing perovskite quantum dots;

[0010] S2, using the solution obtained in step S1 as a raw material, and preparing the ytterbium-doped perovskite quantum dot material by a hot injection method.

[0011] Optionally, in step S2, the thermal injection method includes at least one of a halogen thermal injection method or a cesium thermal injection method.

[0012] Optionally, the halogen thermal injection method includes the following steps: mixing a lead source, a ytterbium source, an aluminum source, a cesium source, oleic acid, an amine of C8-C 20 and an olefin of C 12 -C 24 , heating to 100-130°C and keeping warm under vacuum for 30-60 minutes, continuously heating to 220-280°C under a protective atmosphere, preferably heating to 240-270°C; injecting a halogen source, reacting for 10 seconds to 10 minutes, and then cooling. The protective atmosphere may refer to a gas atmosphere that does not chemically react with the reactants in the system, and can protect the reactants in the system from reacting with oxygen, water vapor, etc. in the air. Generally, the protective atmosphere may be a nitrogen atmosphere or an inert gas atmosphere.

[0013] Optionally, the cesium thermal injection method includes the following steps: mixing a lead source, a ytterbium source, an aluminum source, a halogen source, oleic acid, an amine of C8-C 20 and an olefin of C 12 -C 24 , heating to 100-130°C and keeping warm under vacuum for 30-60 minutes, continuously heating to 220-280°C under a protective atmosphere, preferably heating to 240-270°C; injecting a cesium source, reacting for 10 seconds to 10 minutes, and then cooling.

[0014] In the present invention, the vacuum degree during the vacuum heat preservation process is not specifically limited, as long as it can ensure that the reaction system is heat-preserved in a vacuum environment.

[0015] Optionally, in terms of elements, the molar ratio of aluminum: ytterbium: lead: cesium: halogen is (0.5-4):(0.1-4):(1-2):(1-2):(3-15);

[0016] and / or, the volume ratio of the halogen source: oleic acid: amine of C8-C 20 : olefin of C 12 -C 24 is (0.5-2.4):(0.5-2):(0.5-2):(5-10).

[0017] Optionally, the preparation method of the halogen source includes mixing an olefin of C 12 -C 24 , trimethylchlorosilane, and trimethylbromosilane in a volume ratio of (0.5-2):(0.08-4):(0-0.32);

[0018] and / or, the preparation method of the lead source includes mixing a lead-containing compound, oleic acid, an amine of C8-C 20The amine is mixed in a ratio of 1-4 mmol: 1-4 mL: 10-40 mL and heated to clarity;

[0019] And / or, the preparation method of the ytterbium source includes mixing a ytterbium-containing compound, oleic acid, and C8-C 20 The amine is mixed in a ratio of 1-4 mmol: 1-4 mL: 10-40 mL and heated to clarity;

[0020] And / or, the preparation method of the aluminum source includes mixing an aluminum-containing compound, oleic acid, and C8-C 20 The amine is mixed in a ratio of 1-4 mmol: 1-4 mL: 10-40 mL and heated to clarity;

[0021] And / or, the preparation method of the cesium source includes mixing an alcohol solvent and a cesium-containing compound in a ratio of 1-10 mL: 1-10 mmol.

[0022] Optionally, the lead-containing compound includes at least one of lead acetate, lead oxide, basic lead acetate, lead carbonate, and basic lead carbonate;

[0023] And / or, the ytterbium-containing compound includes at least one of ytterbium acetate, ytterbium nitrate, ytterbium isopropoxide, ytterbium carbonate, and ytterbium oxide;

[0024] And / or, the aluminum-containing compound includes at least one of aluminum acetate, aluminum isopropoxide, aluminum sec-butoxide, aluminum nitrate, trimethylaluminum, triethylaluminum, and aluminum n-butoxide;

[0025] And / or, the cesium-containing compound includes at least one of cesium acetate and cesium carbonate;

[0026] And / or, the alcohol solvent includes at least one of ethanol, isopropanol, n-octanol, and methanol;

[0027] And / or, the C8-C 20 The amine includes at least one of oleylamine, octadecylamine, hexadecylamine, n-pentadecylamine, tetradecylamine, dodecylamine, decylamine, and octylamine;

[0028] And / or, the C 12 -C 24 The olefin includes at least one of octadecene, 1-dodecene, 1-tetradecene, and 1-eicosene.

[0029] The present invention also provides an application of the ytterbium-doped perovskite quantum dot material as described above or the ytterbium-doped perovskite quantum dot material prepared by the preparation method as described above in the fields of medical imaging, night vision, food analysis, or solar cells.

[0030] Specifically, the technical solution of the present invention will be fully described below by taking the preparation of Al (aluminum) and Yb co-doped CsPbCl3 as an example. When the halogen injection thermal injection method is used for preparation, the specific operation steps and parameters are as follows:

[0031] Prepare the halogen source solution: 0.5 - 2 ml of octadecene, 0.08 - 0.4 ml of trimethylchlorosilane (TMS-Cl).

[0032] Prepare the lead oleate solution: 1 - 4 mmol of lead acetate, 1 - 4 ml of oleic acid and 10 - 40 ml of octadecene are added to a three-necked flask and mixed. Heat to 100 - 130 °C, evacuate and maintain for 1 - 2 hours, then pass nitrogen and continue to heat up to 150 - 180 °C and maintain for 10 - 20 minutes until the solution is completely clear and transparent, then cool below 100 °C, take out, seal and store in the dark.

[0033] Prepare the ytterbium oleate solution: 1 - 4 mmol of ytterbium acetate, 1 - 4 mmol of oleic acid and 10 - 40 ml of octadecene are added to a three-necked flask and mixed. Heat to 100 - 130 °C, evacuate and maintain for 1 - 2 hours, then pass nitrogen and continue to heat up to 150 - 180 °C and maintain for 10 - 20 minutes until the solution is completely clear and transparent, then cool below 100 °C, take out, seal and store in the dark.

[0034] Prepare the aluminum oleate solution: 1 - 4 mmol of aluminum acetate, 1 - 4 mmol of oleic acid and 10 - 40 ml of octadecene are added to a three-necked flask and mixed. Heat to 100 - 130 °C, evacuate and maintain for 1 - 2 hours, then pass nitrogen and continue to heat up to 150 - 180 °C and maintain for 10 - 20 minutes until the solution is completely clear and transparent, then cool below 100 °C, take out, seal and store in the dark.

[0035] Prepare the cesium acetate ethanol solution: 1 - 10 ml of absolute ethanol and 1 - 10 mmol of cesium acetate are mixed and ultrasonically stirred in an ultrasonic machine until the cesium acetate particles are completely dissolved and the solution is clear and transparent. The solution is sealed and stored in the dark.

[0036] Mix the lead oleate solution, ytterbium oleate solution, aluminum oleate solution, cesium acetate ethanol solution, oleic acid, oleylamine and octadecene into a three-necked flask. By element, heat up to 100 - 130 °C and keep under vacuum for 30 - 60 minutes, then continue to heat up to 240 - 280 °C in a nitrogen environment, inject the halogen source solution, react for 10 seconds - 10 minutes and quickly cool.

[0037] In the present invention, the specific application method of the ytterbium-doped perovskite quantum dot material provided is conventional in the field and will not be specifically limited herein.

[0038] The technical solution of the present invention has the following advantages:

[0039] The ytterbium-doped perovskite quantum dot material provided by the present invention has a structural formula composition of: CsAl m Yb n Pb (1-m-n) Cl x Br (3-x) , where the value range of x is 0.8 - 3, 0 < m ≤ 0.1, and 0 < n ≤ 0.1. In the actual research process, the inventors found that general co-doping elements would inhibit the actual doping amount of Yb, unable to achieve the effect of assisting Yb doping, and even lead to the situation where Yb cannot emit light. In addition, after the auxiliary doping, it may also lead to the deterioration of the storage stability of Yb-doped perovskite quantum dots, affecting the use. The present invention effectively solves the above problems through the limitation of the composition of the ytterbium-doped perovskite quantum dot material, especially the selection of the auxiliary doping element. Among them, the Al ion has a trivalent valence and a much smaller ionic radius than the Pb ion, and has a weak ability to occupy the Pb site. When co-doped with Yb, it will not form an obvious competitive relationship. This is because the Al ion radius is small and it cannot stably occupy the Pb vacancy. Under high-temperature conditions, it is easy to break away to generate new Pb vacancies, increasing the chance of Yb re-entering the Pb site, improving the actual doping concentration of Yb, not introducing a band gap that affects the electron transfer from the host to the Yb energy level, improving the near-infrared luminescence efficiency of Al / Yb-doped CsPbCl3 quantum dots. At the same time, the auxiliary doping of Al can also improve the storage stability of the product.

[0040] The preparation method of the ytterbium-doped perovskite quantum dot material provided by the present invention can be completed by the hot injection method, and the steps are simple. In addition, the added Al source is prone to hydrolysis reaction in a high-temperature reaction environment. The large amount of energy released by hydrolysis will overcome the activation energy for Yb to participate in the reaction, promoting Yb to enter the quantum dot lattice to occupy the Pb site, improving the actual doping concentration of Yb. The method is simple and effective. At the same time, the Al source added during the synthesis generates an oxide and hydroxide self-passivation layer on the surface of the quantum dot after high-temperature hydrolysis, passivating defects and reducing non-radiative recombination, thereby improving the near-infrared luminescence efficiency and storage stability of Al / Yb-doped CsPbCl3 quantum dots, saving complex post-treatment processes. Description of the Drawings

[0041] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0042] Figure 1 It is a comparison diagram of the storage stability of the samples provided in Example 8 and Comparative Example 2 of the present invention;

[0043] Figure 2 It is a comparison chart of the luminescence intensities of the samples provided in Example 8 and Comparative Example 2 of the present invention. Detailed implementation mode

[0044] The following embodiments are provided to better further understand the present invention. They are not limited to the best implementation mode, and do not constitute a limitation to the content and protection scope of the present invention. Any product that is the same as or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior art features falls within the protection scope of the present invention.

[0045] For those embodiments where specific experimental steps or conditions are not indicated, the operations or conditions of the conventional experimental steps described in the literature in this field can be followed. For reagents or instruments whose manufacturers are not indicated, they are all conventional reagent products that can be obtained through commercial purchase.

[0046] Example 1

[0047] This example provides an Al- and Yb-codoped CsPbCl3, which is prepared by the halogen injection thermal injection method. The specific operation steps and parameters are as follows:

[0048] Prepare the halogen source solution: Mix 1 ml of octadecene and 0.2 ml of trimethylchlorosilane (TMS-Cl) for standby.

[0049] Prepare the lead oleate solution: Add 2 mmol of lead acetate, 2 ml of oleic acid, and 18 ml of octadecene to a three-necked flask and mix. Heat to 120 °C, evacuate and maintain for 1 hour, then pass nitrogen and continue to heat up to 150 °C and maintain for 10 minutes until the solution is completely clear and transparent. Then cool to below 100 °C, take out, seal, and store in the dark.

[0050] Prepare the ytterbium oleate solution: Add 2 mmol of ytterbium acetate, 2 mmol of oleic acid, and 18 ml of octadecene to a three-necked flask and mix. Heat to 120 °C, evacuate and maintain for 1 hour, then pass nitrogen and continue to heat up to 180 °C and maintain for 10 minutes until the solution is completely clear and transparent. Then cool to below 100 °C, take out, seal, and store in the dark.

[0051] Prepare the aluminum oleate solution: Add 2 mmol of aluminum acetate, 2 mmol of oleic acid, and 18 ml of octadecene to a three-necked flask and mix. Heat to 120 °C, evacuate and maintain for 1 hour, then pass nitrogen and continue to heat up to 150 °C and maintain for 10 minutes until the solution is completely clear and transparent. Then cool to below 100 °C, take out, seal, and store in the dark.

[0052] Prepare the cesium acetate ethanol solution: Mix 10 ml of absolute ethanol and 10 mmol of cesium acetate, and ultrasonically stir in an ultrasonic machine until the cesium acetate particles are completely dissolved and the solution is clear and transparent. The solution is sealed and stored in the dark.

[0053] Synthesis steps: Mix the lead oleate solution, ytterbium oleate solution, aluminum oleate solution, cesium ethanol acetate solution, oleic acid, oleylamine, and octadecene into a three-necked flask. Among them, in terms of elements, the molar ratio of aluminum: ytterbium: lead: cesium: halogen is 4:4:1:1:7.5, and the volume ratio of the halogen source solution: oleic acid: oleylamine: octadecene is 1.2:1:0.5:5; heat up to 120 °C and keep it under vacuum for 30 minutes, then continue to heat up to 260 °C under a nitrogen environment, inject the halogen source solution, react for 10 seconds, and quickly cool to obtain a crude liquid sample.

[0054] Near-infrared luminescence efficiency test: Centrifuge the obtained crude liquid sample in a centrifuge at 5000 revolutions per minute for 3 minutes, pour out the upper-layer solution, and redisperse the precipitate with n-hexane for performance testing. Use a spectrometer to test the sample of this example, with the test spectral range of 700 - 1100 nm and the excitation light of 365 nm. Add n-hexane to the test cuvette and put it into the spectrometer to correct the baseline, then add the quantum dot solution to the cuvette to test the luminescence spectrum and QY (QY represents the quantum luminescence efficiency); store the sample in the dark and sealed at room temperature for 30 days, and repeat the above test. The specific test results are shown in the following table.

[0055] Examples 2 - 15

[0056] This example provides Al and Yb co-doped CsPbCl3, which is prepared by the hot injection method of injecting halogen. Compared with Example 1, the difference is only that the element molar ratio of aluminum: ytterbium: lead: cesium: halogen in the synthesis steps is different, as shown in the following table specifically.

[0057] Comparative Examples 1 - 3

[0058] This comparative example provides Yb-doped CsPbCl3, which is prepared by the hot injection method of injecting halogen. Compared with Example 1, the difference is only that no aluminum source is added during the synthesis process, and the element molar ratio of aluminum: ytterbium: lead: cesium: halogen is specifically shown in the following table:

[0059] Table 1

[0060]

[0061]

[0062] As can be seen from the data in the above table, the addition of the Al source can effectively promote the luminescence efficiency of Yb under different Yb doping amounts. Since the radius of trivalent Al ions is relatively small, which is quite different from that of Pb ions, it is unstable to occupy the octahedral Pb site under high-temperature conditions. During the detachment process, vacancies are formed, increasing the chance for Yb to re-enter the lattice and occupy the octahedral position, and it will not form a competitive relationship with Yb. Therefore, the luminescence efficiency of Yb is greatly increased. From Examples 1 to 5 in Table 1, it can be seen that while keeping the molar ratio of Yb to Pb unchanged, as the feeding amount of Al increases, the luminescence efficiency of Yb increases significantly. Since the quantum dots mainly emit light from Yb, this indicates that the addition of Al can effectively promote Yb to enter the lattice and increase the actual doping concentration of Yb. The near-infrared luminescence efficiency of the Al-doped sample solution hardly decreases within 30 days, greatly improving the storage stability of the sample. However, the near-infrared luminescence efficiency of the sample solution without Al doping decreases significantly after 30 days of storage and is almost 0, which may be related to the growth of the surface alumina and aluminum hydroxide shell layers. Figure 1 Figure 2 is a comparison chart of the storage stability of the samples provided in Example 8 and Comparative Example 2 of the present invention. The change trends of other examples are similar to those of Example 8, and the change trends of other comparative examples are similar to those of Comparative Example 2. They will not be shown one by one here; from Figure 2 it can be seen that by doping with the Al element, it is found that the luminescence intensity of Example 8 is significantly enhanced compared to Comparative Example 2, and the luminescence peak position is 980 nm.

[0063] Examples 16 - 20

[0064] This example provides an Al- and Yb-codoped CsPbCl3, which is prepared by the halogen injection thermal injection method. Compared with Example 13, the only difference is the heating temperature before injecting the halogen source solution (i.e., the reaction after injecting the halogen source solution), as shown in the following table.

[0065] Examples 21 - 25

[0066] This example provides an Al- and Yb-codoped CsPbCl3, which is prepared by the halogen injection thermal injection method. Compared with Example 8, the only difference is the heating temperature before injecting the halogen source solution (i.e., the reaction after injecting the halogen source solution), as shown in the following table.

[0067] Table 2

[0068]

[0069] As can be seen from the data in the above table, different reaction temperatures have a certain impact on the near-infrared luminescence efficiency. The preferred reaction temperature range is 240°C to 270°C, and among them, the optimal reaction temperature is 260°C.

[0070] Example 26

[0071] This embodiment provides an Al- and Yb-codoped CsPbCl3, which is prepared by the halogen injection thermal injection method. The specific operation steps and parameters are as follows:

[0072] Prepare the halogen source solution: Mix 0.5 ml of octadecene and 0.08 ml of trimethylchlorosilane (TMS-Cl).

[0073] Prepare the lead oleate solution: Add 1 mmol of lead acetate, 1 ml of oleic acid, and 10 ml of octadecene to a three-necked flask and mix. Heat to 120 °C, evacuate and maintain for 1 hour, then pass nitrogen and continue to heat to 150 °C and maintain for 10 minutes until the solution is completely clear and transparent. Then cool to below 100 °C, take out, seal, and store in the dark.

[0074] Prepare the ytterbium oleate solution: Add 1 mmol of ytterbium acetate, 1 mmol of oleic acid, and 10 ml of octadecene to a three-necked flask and mix. Heat to 120 °C, evacuate and maintain for 1 hour, then pass nitrogen and continue to heat to 150 °C and maintain for 10 minutes until the solution is completely clear and transparent. Then cool to below 100 °C, take out, seal, and store in the dark.

[0075] Prepare the aluminum oleate solution: Add 1 mmol of aluminum acetate, 1 mmol of oleic acid, and 10 ml of octadecene to a three-necked flask and mix. Heat to 120 °C, evacuate and maintain for 1 hour, then pass nitrogen and continue to heat to 150 °C and maintain for 10 minutes until the solution is completely clear and transparent. Then cool to below 100 °C, take out, seal, and store in the dark.

[0076] Prepare the cesium acetate ethanol solution: Mix 1 ml of absolute ethanol and 1 mmol of cesium acetate, and ultrasonically stir in an ultrasonic machine until the cesium acetate particles are completely dissolved and the solution is clear and transparent. Seal and store the solution in the dark.

[0077] Synthesis steps: Mix the lead oleate solution, ytterbium oleate solution, aluminum oleate solution, cesium acetate ethanol solution, oleic acid, oleylamine, and octadecene into a three-necked flask. Among them, in terms of elements, the molar ratio of aluminum: ytterbium: lead: cesium: halogen is 4:4:1:1:3, and the volume ratio of the halogen source solution: oleic acid: oleylamine: octadecene is 0.58:1:0.5:5. Heat to 120 °C and keep it under vacuum for 30 minutes, then continue to heat to 260 °C under a nitrogen environment, inject the halogen source solution, react for 10 seconds, and quickly cool. The performance test method is the same as that in Example 1.

[0078] Example 27

[0079] This embodiment provides an Al- and Yb-codoped CsPbCl3, which is prepared by the halogen injection thermal injection method. The specific operation steps and parameters are as follows:

[0080] Prepare a halogen source solution: 2 ml of octadecene, 0.4 ml of trimethylchlorosilane (TMS-Cl).

[0081] Prepare a lead oleate solution: 4 mmol of lead acetate, 4 ml of oleic acid and 40 ml of octadecene are added to a three-necked flask and mixed. Heat to 120 °C, evacuate and maintain for 1 hour, then pass nitrogen and continue to heat up to 180 °C and maintain for 20 minutes until the solution is completely clear and transparent. Then cool to below 100 °C, take out, seal and store in the dark.

[0082] Prepare a ytterbium oleate solution: 4 mmol of ytterbium acetate, 4 mmol of oleic acid and 40 ml of octadecene are added to a three-necked flask and mixed. Heat to 120 °C, evacuate and maintain for 1 hour, then pass nitrogen and continue to heat up to 180 °C and maintain for 20 minutes until the solution is completely clear and transparent. Then cool to below 100 °C, take out, seal and store in the dark.

[0083] Prepare an aluminum oleate solution: 4 mmol of aluminum acetate, 4 mmol of oleic acid and 40 ml of octadecene are added to a three-necked flask and mixed. Heat to 120 °C, evacuate and maintain for 1 hour, then pass nitrogen and continue to heat up to 180 °C and maintain for 20 minutes until the solution is completely clear and transparent. Then cool to below 100 °C, take out, seal and store in the dark.

[0084] Prepare a cesium acetate ethanol solution: 10 ml of absolute ethanol and 10 mmol of cesium acetate are mixed and ultrasonically stirred in an ultrasonic machine until the cesium acetate particles are completely dissolved and the solution is clear and transparent. The solution is sealed and stored in the dark.

[0085] Synthesis steps: Mix the lead oleate solution, ytterbium oleate solution, aluminum oleate solution, cesium acetate ethanol solution, oleic acid, oleylamine and octadecene into a three-necked flask. Among them, in terms of elements, the molar ratio of aluminum: ytterbium: lead: cesium: halogen is 4:4:1:1:15, and the volume ratio of the halogen source solution: oleic acid: oleylamine: octadecene is 2.4:1:0.5:5; Heat up to 120 °C and keep it under vacuum for 60 minutes, then continue to heat up to 260 °C in a nitrogen environment, inject the halogen source solution, react for 10 seconds and quickly cool. The performance test method is the same as that in Example 1.

[0086] Example 28

[0087] This example provides an Al and Yb co-doped CsPbCl 2.25 Br 0.75 , which is prepared by the hot injection method of injecting halogen. The specific operation steps and parameters are as follows:

[0088] Prepare a halogen source solution: Mix 1 ml of octadecene, 0.15 ml of trimethylchlorosilane (TMS-Cl) and 0.05 ml of trimethylbromosilane (TMS-Br) for standby.

[0089] All other steps are the same as those in Example 1.

[0090] Example 29

[0091] This example provides Al- and Yb-codoped CsPbCl3, which is prepared by the hot injection method with halogen injection. The specific operation steps and parameters are as follows:

[0092] Prepare the halogen source solution: 1 ml of octadecene and 0.2 ml of trimethylchlorosilane (TMS-Cl).

[0093] Prepare the lead oleate solution: 2 mmol of lead acetate, 2 ml of oleic acid, and 18 ml of octadecene are added to a three-necked flask and mixed. Heat to 120 °C, evacuate and maintain for 1 hour, then pass nitrogen and continue to heat to 150 °C and maintain for 10 minutes until the solution is completely clear and transparent. Then cool to below 100 °C, take out, seal, and store in the dark.

[0094] Prepare the ytterbium oleate solution: 2 mmol of ytterbium nitrate, 2 mmol of oleic acid, and 18 ml of octadecene are added to a three-necked flask and mixed. Heat to 120 °C, evacuate and maintain for 1 hour, then pass nitrogen and continue to heat to 180 °C and maintain for 10 minutes until the solution is completely clear and transparent. Then cool to below 100 °C, take out, seal, and store in the dark.

[0095] Prepare the aluminum oleate solution: 2 mmol of aluminum isopropoxide, 2 mmol of oleic acid, and 18 ml of octadecene are added to a three-necked flask and mixed. Heat to 120 °C, evacuate and maintain for 1 hour, then pass nitrogen and continue to heat to 150 °C and maintain for 10 minutes until the solution is completely clear and transparent. Then cool to below 100 °C, take out, seal, and store in the dark.

[0096] Prepare the cesium acetate ethanol solution: 10 ml of absolute ethanol and 10 mmol of cesium acetate are mixed and ultrasonically stirred in an ultrasonic machine until the cesium acetate particles are completely dissolved and the solution is clear and transparent. The solution is sealed and stored in the dark.

[0097] Synthesis step: Mix the lead oleate solution, ytterbium oleate solution, aluminum oleate solution, cesium acetate ethanol solution, oleic acid, oleylamine, and octadecene in a three-necked flask. Among them, in terms of elements, the molar ratio of aluminum: ytterbium: lead: cesium: halogen is 4:4:1:1:7.5. The volume ratio of the halogen source solution: oleic acid: oleylamine: octadecene is 1.2:1:0.5:5. Heat to 120 °C and keep under vacuum for 30 minutes, then continue to heat to 260 °C under a nitrogen atmosphere, inject the halogen source solution, react for 10 seconds, and quickly cool. The performance testing method is the same as that in Example 1.

[0098] Example 30

[0099] This embodiment provides an Al- and Yb-codoped CsPbCl3, which is prepared by a halogen injection thermal injection method. The specific operation steps and parameters are as follows:

[0100] Prepare a halogen source solution: 1 ml of octadecene and 0.2 ml of trimethylchlorosilane (TMS-Cl).

[0101] Prepare a lead oleate solution: 2 mmol of lead oxide, 2 ml of oleic acid and 18 ml of octadecene are added to a three-necked flask and mixed. Heat to 120 °C, evacuate and maintain for 1 hour, then pass nitrogen and continue to heat up to 150 °C and maintain for 10 minutes until the solution is completely clear and transparent. Then cool to below 100 °C, take out, seal and store in the dark.

[0102] Prepare a ytterbium oleate solution: 2 mmol of ytterbium isopropoxide, 2 mmol of oleic acid and 18 ml of octadecene are added to a three-necked flask and mixed. Heat to 120 °C, evacuate and maintain for 1 hour, then pass nitrogen and continue to heat up to 180 °C and maintain for 10 minutes until the solution is completely clear and transparent. Then cool to below 100 °C, take out, seal and store in the dark.

[0103] Prepare an aluminum oleate solution: 2 mmol of aluminum sec-butoxide, 2 mmol of oleic acid and 18 ml of octadecene are added to a three-necked flask and mixed. Heat to 120 °C, evacuate and maintain for 1 hour, then pass nitrogen and continue to heat up to 150 °C and maintain for 10 minutes until the solution is completely clear and transparent. Then cool to below 100 °C, take out, seal and store in the dark.

[0104] Prepare a cesium acetate ethanol solution: 10 ml of absolute ethanol and 10 mmol of cesium acetate are mixed and ultrasonically stirred in an ultrasonic machine until the cesium acetate particles are completely dissolved and the solution is clear and transparent. The solution is sealed and stored in the dark.

[0105] Synthesis steps: Mix the lead oleate solution, ytterbium oleate solution, aluminum oleate solution, cesium acetate ethanol solution, oleic acid, oleylamine and octadecene into a three-necked flask. Among them, in terms of elements, the molar ratio of aluminum: ytterbium: lead: cesium: halogen is 4:4:1:1:7.5. The volume ratio of the halogen source solution: oleic acid: oleylamine: octadecene is 1.2:1:0.5:5. Heat to 120 °C and keep it under vacuum for 30 minutes, then continue to heat up to 260 °C in a nitrogen environment, inject the halogen source solution, react for 10 seconds and quickly cool. The performance test method is the same as that in Example 1.

[0106] Example 31

[0107] This embodiment provides an Al- and Yb-codoped CsPbCl3, which is prepared by a cesium injection thermal injection method. The specific operation steps and parameters are as follows:

[0108] Prepare a halogen source solution, a lead oleate solution, a ytterbium oleate solution, an aluminum oleate solution, and a cesium acetate ethanol solution respectively, with the method the same as in Example 1.

[0109] Synthesis steps: Mix the lead oleate solution, the ytterbium oleate solution, the aluminum oleate solution, the halogen source solution, oleic acid, oleylamine, and octadecene into a three-necked flask. Among them, in terms of elements, the molar ratio of aluminum: ytterbium: lead: cesium: halogen is 4:4:1:1:7.5. The volume ratio of the halogen source solution: oleic acid: oleylamine: octadecene is 1.2:1:0.5:5. Heat up to 120 °C and keep it under vacuum for 30 minutes, then continue to heat up to 260 °C under a nitrogen environment, inject the cesium acetate ethanol solution, react for 10 seconds, and quickly cool. The performance test method is the same as in Example 1.

[0110] Example 32

[0111] This example provides an Al, Yb co-doped CsPbCl3, which is prepared by the hot injection method of injecting halogen. Compared with Example 1, the only difference is that cesium oleate is used instead of cesium acetate ethanol: The preparation method of the cesium oleate solution is: Mix 1 ml of oleic acid, 9 ml of octadecene, and 1 mmol of cesium acetate in a three-necked flask, heat up to 120 °C, evacuate for 1 h, and then take it out and store it sealed.

[0112] Table 3

[0113]

[0114]

[0115] Comparative Examples 4 - 17

[0116] This comparative example provides a divalent metal, Yb co-doped CsPbCl3, which is prepared by the hot injection method of injecting halogen. Compared with Example 1, the only difference is that a divalent metal source is used instead of an aluminum source for doping. The specific divalent metal source and raw material ratio are shown in the following table:

[0117] Table 4

[0118]

[0119]

[0120] As can be seen from the data in the above table, by doping divalent metal ions in different proportions, it is found that there is almost no improvement in the luminescence efficiency of Yb, and even the near-infrared QY is greatly inhibited. This is because the divalent ions have the same valence state as Pb ions and will preferentially replace Pb ions with Yb ions, thereby inhibiting the doping concentration and luminescence efficiency of Yb. In addition, the storage stability decreases significantly.

[0121] Comparative Examples 18 - 23

[0122] This comparative example provides a trivalent metal and Yb co-doped CsPbCl3, which is prepared by the halogen injection thermal injection method. Compared with Example 1, the difference is only that a trivalent metal source is used instead of an aluminum source for doping. The specific trivalent metal source and raw material ratio are shown in the following table:

[0123] Table 5

[0124]

[0125]

[0126] It can be seen from the data in the above table that the co-doping of different trivalent rare earth ions and Yb promotes Yb luminescence, but the effect is not as excellent as that of Al. This is because the rare earth ion radii are similar, and occupying the Pb position will form a competitive relationship, thus weakening the effect of double doping to promote Yb luminescence. In addition, the storage stability of the trivalent metal source doping is significantly reduced.

[0127] Comparative Example 24

[0128] This comparative example provides an Al and Yb co-doped CsPbBr3, which is prepared by the halogen injection thermal injection method. Compared with Example 1, the difference is only that the composition of the halogen source solution is different, and its preparation method is: 1 ml of ODE is mixed with 0.2 ml of trimethylbromosilane.

[0129] Table 6

[0130]

[0131] It can be seen from the data in the above table that the near-infrared luminescence efficiency of the Al and Yb co-doped CsPbBr3 sample is poor, which is related to the host band gap of CsPbBr3. When the band gap is close to 500 nm, the quantum cutting effect weakens because the luminescence energy of Yb at 980 nm depends on the exciton transition cutting transfer before the 490 nm band gap of the host.

[0132] Obviously, the above examples are only for clear illustration and not a limitation of the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A ytterbium-doped perovskite quantum dot material, characterized in that, The structural formula is: CsAl m Yb n Pb (1-m-n) Cl x Br (3-x) , where the value range of x is 0.8 to 3, 0 < m ≤ 0.1, 0 < n ≤ 0.

1.

2. The ytterbium-doped perovskite quantum dot material according to claim 1, wherein The value range of x is 2 to 3, the value range of m is 0.001 to 0.05, and the value range of n is 0.005 to 0.

1.

3. A method for preparing the ytterbium-doped perovskite quantum dot material according to claim 1 or 2, characterized in that, It includes the following steps: S1. Obtain a lead source, a cesium source, a halogen source, an aluminum source, and a ytterbium source required for the synthesis of perovskite quantum dots; S2. Using the solution obtained in step S1 as a raw material, prepare a ytterbium-doped perovskite quantum dot material by a hot injection method.

4. The preparation method of the ytterbium-doped perovskite quantum dot material according to claim 3, wherein, In step S2, the hot injection method includes at least one of a halogen injection hot injection method or a cesium injection hot injection method.

5. The preparation method of the ytterbium-doped perovskite quantum dot material according to claim 4, wherein The halogen injection thermal injection method includes the following steps: mixing a lead source, a ytterbium source, an aluminum source, a cesium source, oleic acid, an amine with C8-C 20 and C 12 -C 24 alkenes, heating to 100-130°C and holding under vacuum for 30-60 minutes, then continuing to heat to 220-280°C under a protective atmosphere. Preferably, the temperature is raised to 240-270°C; injecting a halogen source, reacting for 10 seconds to 10 minutes, and then cooling.

6. The preparation method of the ytterbium-doped perovskite quantum dot material according to claim 4, characterized in that, The cesium injection thermal injection method includes the following steps: mixing a lead source, a ytterbium source, an aluminum source, a halogen source, oleic acid, an amine with C8-C 20 and an olefin with C 12 -C 24 , heating to 100-130 °C and holding under vacuum for 30-60 minutes, then continuing to heat to 220-280 °C under a protective atmosphere. Preferably, the temperature is raised to 240-270 °C; injecting a cesium source, reacting for 10 seconds to 10 minutes, and then cooling.

7. The preparation method of the ytterbium-doped perovskite quantum dot material according to claim 5 or 6, characterized in that, By element, the molar ratio of aluminum: ytterbium: lead: cesium: halogen is (0.5 to 4): (0.1 to 4): (1 to 2): (1 to 2): (3 to 15); and / or, the halogen source: oleic acid: C8-C 20 amine: C 12 -C 24 The volume ratio of the olefin is (0.5-2.4):(0.5-2):(0.5-2):(5-10).

8. The preparation method of the ytterbium-doped perovskite quantum dot material according to any one of claims 3 to 6, characterized in that, The preparation method of the halogen source includes mixing an olefin having C 12 to C 24 with trimethylchlorosilane and trimethylbromosilane in a volume ratio of (0.5 to 2):(0.08 to 4):(0 to 0.32); And / or, the preparation method of the lead source includes mixing a lead-containing compound, oleic acid, and an amine with C8-C 20 in a ratio of 1-4 mmol: 1-4 mL: 10-40 mL, and heating to clarity; And / or, the preparation method of the ytterbium source includes mixing a ytterbium-containing compound, oleic acid, and an amine having C8-C 20 in a ratio of 1-4 mmol: 1-4 mL: 10-40 mL, and heating to clarity; And / or, the preparation method of the aluminum source includes mixing an aluminum-containing compound, oleic acid, and an amine having C8-C 20 in a ratio of 1-4 mmol: 1-4 mL: 10-40 mL, and heating to clarity; And / or, the preparation method of the cesium source includes mixing an alcohol solvent and a cesium-containing compound in a ratio of 1 to 10 mL: 1 to 10 mmol.

9. The preparation method of the ytterbium-doped perovskite quantum dot material according to claim 8, characterized in that, The lead-containing compound includes at least one of lead acetate, lead oxide, basic lead acetate, lead carbonate, and basic lead carbonate; And / or, the ytterbium-containing compound includes at least one of ytterbium acetate, ytterbium nitrate, ytterbium isopropoxide, ytterbium carbonate, and ytterbium oxide; And / or, the aluminum-containing compound includes at least one of aluminum acetate, aluminum isopropoxide, aluminum sec-butoxide, aluminum nitrate, trimethylaluminum, triethylaluminum, and aluminum n-butoxide; And / or, the cesium-containing compound includes at least one of cesium acetate and cesium carbonate; And / or, the alcohol solvent includes at least one of ethanol, isopropanol, n-octanol, and methanol; and / or, the amine of C8-C 20 includes at least one of oleylamine, octadecylamine, cetylamine, n-pentadecylamine, tetradecylamine, dodecylamine, decylamine, and octylamine; and / or, said C 12 ~C 24 The olefins include at least one of octadecene, 1-dodecene, 1-tetradecene, and 1-eicosene.

10. Use of the ytterbium-doped perovskite quantum dot material according to claim 1 or 2 or the ytterbium-doped perovskite quantum dot material prepared by the preparation method according to any one of claims 3 to 9 in the fields of medical imaging, night vision, food analysis, or solar cells.

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