A metal-doped A2BX5 crystal, its preparation method, thin film, and photodetector

Abstract

This application belongs to the field of photodetector technology, and relates to a method for preparing a metal-doped A2BX5 crystal, a thin film thereof, and a photodetector. The method for preparing the metal-doped A2BX5 crystal includes providing a first mixed solution comprising AX, BX2, CX2, and a first solvent; subjecting the first mixed solution to a first heat treatment to obtain a second mixed solution; adding a metal chelating agent to the second mixed solution to obtain a third mixed solution; adding a second solvent to the third mixed solution and performing a second heat treatment to obtain a metal-doped A2BX5 crystal, wherein C is doped in the A2BX5 crystal. The metal chelating agent can bind with B ions in the third mixed solution to form a dynamic supramolecular coordination structure, thereby limiting the nucleation rate of B ions and improving the stability of the metal-doped A2BX5 crystal.

Description

Technical Field

[0001] This application relates to the field of photodetector technology, and more specifically, to a metal-doped A2BX5 crystal, its preparation method, thin film, and photodetector. Background Technology

[0002] Existing technologies prepare metal-doped A2BX5 crystals through organic ligand exchange. However, the two-dimensional perovskite materials prepared by this method exhibit low stability and low luminescence activity. Summary of the Invention

[0003] To address the aforementioned technical problems, this application provides a method for preparing metal-doped A2BX5 crystals, the method employing the following technical solution:

[0004] A method for preparing a metal-doped A2BX5 crystal, the method comprising:

[0005] A first mixture is provided, the first mixture comprising AX, BX2, CX2 and a first solvent;

[0006] The first mixture is subjected to a first heating treatment to obtain a second mixture solution;

[0007] A metal chelating agent is added to the second mixed solution to obtain a third mixed solution;

[0008] A second solvent is added to the third mixed solution, and a second heat treatment is performed to obtain a metal-doped A2BX5 crystal, wherein C is doped in the A2BX5 crystal;

[0009] Wherein, A is selected from at least one of cesium ion, formamidinium ion, methylammonium ion, n-octylammonium ion, phenylethylammonium ion, benzylammonium ion, and tert-butylammonium ion; B is selected from at least one of lead ion and tin ion; C is selected from at least one of manganese, iron, nickel, copper, zinc, aluminum, and molybdenum; X is selected from at least one of iodide ion, bromide ion, and chloride ion; and the metal chelating agent includes at least one of carboxylic acid chelating agents and organic polyphosphonic acid chelating agents.

[0010] Accordingly, this application also provides a metal-doped A2BX5 crystal, which is prepared by any of the methods described in the above embodiments.

[0011] Accordingly, this application also provides a thin film containing a metal-doped A2BX5 crystal, wherein the metal-doped A2BX5 crystal is the metal-doped A2BX5 crystal described in the above embodiments, or is prepared by any of the methods described in the above embodiments.

[0012] Accordingly, this application also provides a photodetector, which includes an anode, a functional layer and a cathode stacked sequentially, wherein the functional layer is the thin film described in the above embodiments.

[0013] Compared with the prior art, the embodiments of this application have the following beneficial effects:

[0014] Metal chelating agents can bind with B ions in the third mixed solution to form a dynamic supramolecular coordination structure, thereby limiting the nucleation rate of B ions and improving the stability of metal-doped A2BX5 crystals. Attached Figure Description

[0015] To more clearly illustrate the solutions in this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 This is a flowchart of a method for preparing a metal-doped A2BX5 crystal according to an embodiment of this application;

[0017] Figure 2a This is a schematic diagram of the fluorescence intensity of the metal-doped A2BX5 crystal under ultraviolet light irradiation in Embodiment 1 of this application;

[0018] Figure 2b This is a schematic diagram of the fluorescence intensity of the metal-doped A2BX5 crystal under ultraviolet light irradiation in Comparative Example 1 of this application.

[0019] Figure 3 This is the emission spectrum of Example 1 of the metal-doped A2BX5 crystal of this application;

[0020] Figure 4 This is the emission spectrum of Example 2 of the metal-doped A2BX5 crystal of this application;

[0021] Figure 5 This is the emission spectrum of Example 3 of the metal-doped A2BX5 crystal of this application;

[0022] Figure 6 This is the emission spectrum of Example 4 of the metal-doped A2BX5 crystal of this application;

[0023] Figure 7 This is the emission spectrum of Example 5 of the metal-doped A2BX5 crystal of this application;

[0024] Figure 8This is the emission spectrum of Example 6 of the metal-doped A2BX5 crystal of this application;

[0025] Figure 9 This is the emission spectrum of Example 7 of the metal-doped A2BX5 crystal of this application;

[0026] Figure 10 This is the emission spectrum of Comparative Example 1, which is a metal-doped A2BX5 crystal according to an embodiment of this application.

[0027] Figure 11 This is the emission spectrum of Comparative Example 2, which is a metal-doped A2BX5 crystal according to an embodiment of this application.

[0028] Figure 12 This is the X-ray photoelectron spectrum of the metal-doped A2BX5 crystal in this application embodiment. Detailed Implementation

[0029] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Furthermore, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application.

[0030] In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in its actual use or operating state, specifically the orientation shown in the accompanying drawings; while "inner" and "outer" refer to the outline of the device. Furthermore, in the description of this application, the term "comprising" means "including but not limited to". The terms first, second, third, etc., are used merely as illustrative purposes and do not impose numerical requirements or establish a numerical order.

[0031] In this application, "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural.

[0032] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c," or "at least one of a, b, and c," can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0033] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0034] To address the above problems, this application provides a method for preparing metal-doped A2BX5 crystals, the method comprising:

[0035] S100, provides a first mixture, the first mixture comprising AX, BX2, CX2 and a first solvent;

[0036] S200, the first mixture is subjected to a first heating treatment to obtain a second mixture;

[0037] S300, a metal chelating agent is added to the second mixed solution to obtain a third mixed solution;

[0038] S400, add a second solvent to the third mixed solution and perform a second heat treatment to obtain a metal-doped A2BX5 crystal, with C doped into the A2BX5 crystal;

[0039] Wherein, A is selected from at least one of cesium ion, formamidinium ion, methylammonium ion, n-octylammonium ion, phenylethylammonium ion, benzylammonium ion, and tert-butylammonium ion; B is selected from at least one of lead ion and tin ion; C is selected from at least one of manganese, iron, nickel, copper, zinc, aluminum, and molybdenum; X is selected from at least one of iodide ion, bromide ion, and chloride ion; and the metal chelating agent includes at least one of carboxylic acid chelating agents and organic polyphosphonic acid chelating agents.

[0040] In this embodiment, firstly, the metal chelating agent has lone pairs of electrons in its molecular structure, thus enabling it to bind with B ions (lead and / or tin ions) through coordination bonds via chelation, forming a dynamic supramolecular coordination structure that restricts the movement and coordination of B ions. The principle behind this dynamic supramolecular coordination structure restricting B ion movement is as follows: the dynamic supramolecular coordination structure resembles a cage, within which the B ion resides. The metal chelating agent interacts with the B ion through chemical bonds, restricting its binding to other substances.

[0041] In the nucleation process of A2BX5 crystals, a certain saturation concentration of boron ions in the third mixed solution is required for crystal nuclei to form. Therefore, the dynamic supramolecular structure formed by the metal chelator and boron ions restricts the nucleation of calcium-doped A2BX5 crystals, thereby slowing down the nucleation rate and growth rate of metal-doped A2BX5 crystals. Consequently, the resulting metal-doped A2BX5 crystals exhibit a slower growth rate at room temperature, resulting in higher stability.

[0042] Secondly, existing technologies use ligand exchange to prepare amino-terminated metal-doped A2BX5 crystals. However, the surface of these crystals is covered by insulating ligands, resulting in low charge transfer efficiency and low luminescence intensity under ultraviolet light. Figure 2b As shown, its intensity is relatively low. However, the metal-doped A2BX5 crystal prepared in this embodiment was not prepared using ligand exchange; therefore, the metal-doped A2BX5 crystal avoids covering the insulating ligand, hence its luminescence intensity under ultraviolet light irradiation is as shown... Figure 2a As shown, its luminous intensity is relatively high.

[0043] In summary, the metal-doped A2BX5 crystal prepared in the embodiments of this application has high luminescence intensity and strong stability.

[0044] Furthermore, the carboxylic acid chelating agent includes at least one selected from m-4-pyridinecarboxylic acid, phthalic acid, trimesolic acid, terephthalic acid, and pyridine 3,5-dicarboxylic acid; and / or,

[0045] At least one of the following organic polyphosphonic acid chelating agents: 1,1'-bis(diphenylphosphine)ferrocene, hydroxyethylidene diphosphonic acid, and bis(triphenylphosphine)palladium dichloride; and / or,

[0046] AX includes CsCl, CsBr, CsI, CH3NH3Br, CH3(CH2)7NH3Cl, CH3(CH2)7NH3Cl; and / or,

[0047] BX2 includes at least one of PbCl2, PbBr2, PbI2, SnCl2, SnBr2, and SnI2; and / or, CX2 includes at least one of NiBr2, NiI2, NiCl2, MoBr2, ZnBr2, and their hydrates.

[0048] In this embodiment, the carboxylic acid chelating agent and the organic polyphosphonic acid chelating agent can coordinate with the metal ions (B ions) at multiple sites. This strong interaction can better restrict the activity of the metal ions, thereby more precisely controlling the nucleation and growth process of the metal-doped A2BX5 crystal and further improving the stability of the material. The selection of AX, BX2, and CX2 will determine the luminescence intensity and other properties of the final A2BX5 crystal, ensuring that the A2BX5 crystal meets the requirements.

[0049] Further, the molar ratio of CX2, BX2, and AX is (2–6):(1–3):1; optionally, the molar ratio of CX2, BX2, and AX is (3–5):(1.5–2.5):1; and / or,

[0050] The molar ratio of BX2 to the metal chelating agent is (1-20):1.

[0051] In this embodiment, the molar ratio range of CX2, BX2, and AX enables a high efficiency and yield of the final metal-doped A2BX5 crystal. The molar ratio of PbBr2 to the metal chelating agent allows the metal chelating agent to fully coordinate with the B ions in BX2, thereby limiting the improvement of the stability of the A2BX5 crystal. The molar ratio of CX2, BX2, and AX can be any ratio among 2:1:1, 3:2:1, 4:2:1, 5:2:1, and 6:3:1. Optionally, when the molar ratio is (3-5):(1.5-2.5):1, the yield of the metal-doped A2BX5 crystal is higher. The molar ratio of BX2 to the metal chelating agent can be any value or a range formed by any two values ​​among 1:1, 2:1, 4:1, 6:1, 8:1, 1:1, 10:1, 12:1, 14:1, 16:1, 18:1, and 20:1.

[0052] Further, the first solvent includes at least one selected from dimethylformamide, dimethylformamide, γ-butyrolactone, dimethyl sulfoxide, and N,N-dimethylacetamide; and / or,

[0053] The second solvent includes at least one selected from toluene, n-hexane, diethyl ether, trifluorotoluene, iodobenzene, sec-butanol, anisole, ethyl acetate, and methyl acetate; and / or,

[0054] Metal-doped A2BX5 crystals include at least one of Cs2PbBr5, Cs2SnCl5, (CH(NH2)2)2SnI5, and Cs2SbBr5.

[0055] In this embodiment, the first solvent can fully dissolve the mixture formed by CX2, BX2, and AX to form a homogeneous first mixture. The second solvent enables the A2BX5 crystals to be fully extracted, thereby improving the production efficiency of A2BX5 crystals.

[0056] Furthermore, the temperature of the first heat treatment is 40℃~100℃; and / or,

[0057] The first heat treatment also involves stirring at a speed of 200 to 500 rpm.

[0058] Furthermore, the temperature of the second heat treatment is 100℃~160℃; and / or,

[0059] The second heat treatment also involves stirring at a speed of 100 rpm to 300 rpm; and / or,

[0060] The pressure for the second heat treatment is 12 MPa to 30 MPa; and / or,

[0061] The second heat treatment takes 30 minutes to 2 hours.

[0062] In this embodiment, the rotation speed of the first heating treatment ensures that CX2, BX2, and AX are fully dissolved and uniformly mixed, while the temperature ensures that CX2, BX2, and AX do not undergo unexpected chemical reactions. The temperature of the second heating treatment ensures that no unexpected chemical reactions occur, the pressure maintains the concentration of the solution and the stability of the reaction system, and the rotation speed and time ensure that the metal chelating agent is fully coordinated with the B ions.

[0063] It should be understood that the temperature of the first heat treatment can be any value or a range formed by any two of the following: 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, and 100℃. The stirring speed of the first heat treatment can be any value or a range formed by any two of the following: 200 rpm, 220 rpm, 240 rpm, 260 rpm, 280 rpm, 300 rpm, 320 rpm, 340 rpm, 360 rpm, 380 rpm, 400 rpm, 420 rpm, 440 rpm, 460 rpm, 480 rpm, and 500 rpm. The temperature for the second heat treatment can be any value or a range formed by any two of the following: 100℃, 105℃, 110℃, 115℃, 120℃, 125℃, 130℃, 135℃, 140℃, 145℃, 150℃, 155℃, and 160℃. The stirring speed for the second heat treatment can be any value or a range formed by any two of the following: 100 rpm, 120 rpm, 140 rpm, 160 rpm, 180 rpm, 200 rpm, 220 rpm, 240 rpm, 260 rpm, 280 rpm, and 300 rpm. The pressure for the second heat treatment can be any value or a range formed by any two of the following: 12 MPa, 14 MPa, 16 MPa, 18 MPa, 20 MPa, 22 MPa, 24 MPa, 26 MPa, 28 MPa, and 30 MPa. The second heat treatment time can be any value or a range formed by any two of the following: 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, and 120 min.

[0064] Accordingly, this application also provides a metal-doped A2BX5 crystal, which is prepared by any of the methods described in the above embodiments.

[0065] In this embodiment, since the metal-doped A2BX5 crystal of this application is prepared by the above method, it has high stability, and compared with the ligand exchange method, the amine-terminated metal-doped A2BX5 crystal prepared has higher luminescence intensity.

[0066] Accordingly, this application also provides a thin film containing a metal-doped A2BX5 crystal, wherein the metal-doped A2BX5 crystal is the metal-doped A2BX5 crystal of the above embodiments, or is prepared by any of the methods in the above embodiments.

[0067] In this embodiment, because it contains the metal-doped A2BX5 crystal as described in the above embodiments, the thin film has a high lifespan and luminous intensity.

[0068] Accordingly, this application also provides a photodetector, which includes an anode, a functional layer and a cathode stacked sequentially, wherein the functional layer is a thin film as described in the above embodiments.

[0069] In this embodiment, because it contains the metal-doped A2BX5 crystal as described in the above embodiments, the photodetector has a high luminous intensity and a long service life.

[0070] Furthermore, the photodetector includes a first electrode, a hole functional layer, a functional layer, an electron functional layer, and a second electrode stacked sequentially.

[0071] Optionally, the average thickness of the first electrode is 30–40 nm; and / or, the average thickness of the hole functional layer is 20–80 nm; and / or, the average thickness of the electron functional layer is 20–80 nm; and / or, the average thickness of the second electrode is 30–40 nm.

[0072] In this embodiment, the average thickness of the first electrode can be any value or any two values ​​from 30nm, 31nm, 32nm, 33nm, 34nm, 35nm, 36nm, 37nm, 38nm, 39nm, and 40nm. The thickness of the hole functional layer can be any value or any two values ​​from 20nm, 22nm, 24nm, 26nm, 28nm, 30nm, 32nm, 34nm, 36nm, 38nm, 40nm, 42nm, 44nm, 46nm, 48nm, 50nm, 52nm, 54nm, 56nm, 58nm, 60nm, 62nm, 64nm, 66nm, 68nm, 70nm, 72nm, 74nm, 76nm, 78nm, and 80nm. The average thickness of the second electrode can be any value or any two values ​​from 30nm, 31nm, 32nm, 33nm, 34nm, 35nm, 36nm, 37nm, 38nm, 39nm, and 40nm. The average thickness of the electronic functional layer can be any value or any two values ​​from 20nm, 22nm, 24nm, 26nm, 28nm, 30nm, 32nm, 34nm, 36nm, 38nm, 40nm, 42nm, 44nm, 46nm, 48nm, 50nm, 52nm, 54nm, 56nm, 58nm, 60nm, 62nm, 64nm, 66nm, 68nm, 70nm, 72nm, 74nm, 76nm, 78nm, and 80nm.

[0073] Further, the first electrode and the second electrode independently include one or more of the following: a metal electrode, a silicon-carbon electrode, a doped or undoped metal oxide electrode, and a composite electrode; wherein, the material of the metal electrode is selected from at least one of Al, Ag, Cu, Mo, Au, Ba, Ca, and Mg; the material of the silicon-carbon electrode is selected from at least one of silicon, graphite, carbon nanotubes, graphene, and carbon fibers; the material of the doped or undoped metal oxide electrode is selected from at least one of ITO, FTO, ATO, AZO, GZO, IZO, MZO, and AMO; and the material of the composite electrode is selected from at least one of AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, TiO2 / Ag / TiO2, TiO2 / Al / TiO2, ZnS / Ag / ZnS, ZnS / Al / ZnS, TiO2 / Ag / TiO2, and TiO2 / Al / TiO2.

[0074] And / or, the electronic functional layer includes an electron transport layer and / or an electron injection layer, the materials of which are independently selected from zinc oxide, titanium dioxide, tin dioxide, aluminum oxide, calcium oxide, silicon dioxide, gallium oxide, zirconium oxide, nickel oxide, zirconium trioxide, and C. 60 C 70 At least one of Bphen, BCP, Alq3, and PCBM;

[0075] And / or, the hole functional layer includes a hole transport layer and / or a hole injection layer, wherein the materials of the hole transport layer and the hole injection layer are each independently selected from at least one of PEDOT:PSS, NPB, TCTA, TAPC, CBP, P3HT, spiro-OMeTAD, and MoO3.

[0076] In this embodiment, the selection of the electronic functional layer, the first electrode, the second electrode, and the hole functional layer ensures that the photodetector has high sensitivity and long service life.

[0077] The above solution will be further described below with reference to specific embodiments. The preferred embodiments of this application are detailed below:

[0078] The raw materials used in the embodiments of this application specification are sourced as follows: Cesium bromide (CsBr, 99%) is selected from Aladdin Company; Lead bromide (PbBr2, 99.9%) is selected from Aladdin Company; Dimethylformamide (DMF, analytical grade) is selected from Aladdin Company; Nickel bromide (NiBr2, 98%) is selected from Aladdin Company; Toluene (analytical grade) is selected from Chengdu Kelong Chemical Co., Ltd.

[0079] Example 1:

[0080] This application provides a method for preparing a metal-doped A2BX5 crystal, the method of which is as follows:

[0081] Step 1: Preparation of precursor solution. Add 0.1 mol CsBr powder to a beaker, followed by (0.2 mol) PbBr2 powder and (0.4 mol) NiBr2·5H2O powder. Then add 20 ml DMF solution to the beaker, heat to 60 °C and stir until completely dissolved to obtain the precursor solution.

[0082] Step 2: Prepare the mixed solution. Add 4-pyridinecarboxylic acid to the precursor solution and stir to obtain the mixed solution. The molar ratio of 4-pyridinecarboxylic acid to PbBr2 is 10:1 (optimal value).

[0083] Step 3: Prepare metal-doped A2BX5 crystals. Extract 10 ml of the mixed solution and transfer it to a magnetically stirred reactor, then add 20 ml of toluene. The reactor temperature is 120℃, the pressure is 18 MPa, the stirring speed is 200 rpm, and the stirring time is 1 hour. This allows the precursor solution to release a large amount of Ni at high temperature. 2+ Ions, causing free [PbBr6] in solution. 4- The reaction transforms into a cap-shaped triangular prism of Pb / NiBr8, forming a Cs(Pb / Ni)2Br5 structure. After the reaction is complete, Ni-doped CsPb2Br5 powder is obtained.

[0084] Example 2

[0085] The difference from Example 1 is that in step 2, the molar ratio of PbBr2 to 4-pyridinecarboxylic acid is 1:1.

[0086] Example 3

[0087] It is basically the same as Example 1, except that in step 2, the molar ratio of PbBr2 to 4-pyridinecarboxylic acid is 20:1.

[0088] Example 4

[0089] It is basically the same as Example 1, except that in step 1, the molar ratio of NiBr2·5H2O, PbBr2 and CsBr is 6:2:1.

[0090] Example 5

[0091] It is basically the same as Example 1, except that in step 1, the molar ratio of NiBr2·5H2O, PbBr2 and CsBr is 2:1:1.

[0092] Example 6

[0093] It is basically the same as Example 1, except that in step 1, NiBr2·5H2O is replaced with MnBr2.

[0094] Example 7

[0095] It is basically the same as Example 1, except that in step 2, 4-pyridinecarboxylic acid is replaced with bis(diphenylphosphine)ferrocene.

[0096] Comparative Example 1

[0097] A Ni-doped CsPb2Br5 fluorescent powder is provided.

[0098] Step 1: Add 0.1 mol CsBr powder to a beaker, then add 0.2 mol PbBr2 powder and 0.4 mol NiBr2·5H2O powder in a molar ratio of 1:2 to 20 ml DMF solution, heat to 60 °C and stir to completely dissolve, to obtain a mixed precursor solution;

[0099] Step 2: Add 20 ml of toluene to 10 ml of the solution and heat directly to 120 °C with stirring. Centrifuge the precipitated crystals and filter out excess solvent. Place the crystals in a drying oven at 100 °C for 12 hours to obtain Ni-doped Cs2PbBr5 ternary composite perovskite fluorescent powder.

[0100] Comparative Example 2

[0101] Comparative Example 2 provides a method for preparing CsPb2Br5, specifically as follows: (1) Under nitrogen protection, 0.1 g of cesium carbonate (0.3 mmol), 0.35 mL of oleic acid (1.1 mmol) and 3.75 mL of octadecene are reacted and dissolved completely at 120 °C under an inert atmosphere to obtain solution I; (2) 69 mg of lead bromide (0.188 mmol), 10 mL of oleic acid and 0.5 mL of oleylamine are mixed and dissolved completely at 120 °C under an inert atmosphere to obtain solution II; (3) The temperature of solution II is raised to 160 °C, and 0.4 mL of solution I is injected into solution II (10.5 mL), and the reaction is continued with stirring; (4) After stirring the reaction continuously at the same temperature for 60 min, the reaction solution is obtained, and finally CsPb2Br5 is obtained by centrifugation, separation and washing.

[0102] The metal-doped A2BX5 crystals of Example 1 and Comparative Example 1 were placed under ultraviolet light irradiation to observe their brightness; then the metal-doped A2BX5 crystals of Examples 1-7 and Comparative Examples 1-2 were placed at 80°C and 85% for 100 hours, and the light intensity was tested.

[0103] The light intensity was tested using an Edinburgh Instruments FS5 fluorescence spectrometer (150W xenon lamp source) to characterize the fluorescence properties of the samples. PL spectra of the crystal powders prepared in Examples 1-7 and Comparative Examples 1-2 were obtained.

[0104] Depend on Figure 12 From the four figures (a), (b), (c), and (d), we can see that... Figure 12 In (a), two 3d peaks of Cs are shown, located at 737.3 eV and 723.2 eV, corresponding to the 3d³ / ² and 3d⁵ / ² orbitals, respectively. (b) shows the high-resolution X-ray photoelectron spectra of Pb⁴f and Br⁃d, with corresponding peak positions of 142.4 eV, 137.5 eV, and 68.3 eV, respectively. 69.4 eV corresponds to the 4f⁵ / ², 4f⁷ / ², and 3d³ / ², 3d⁵ / ² orbitals, respectively. Therefore, Pb does not form a zero-valence state. In (c), Br⁃d indicates the interaction between Pb and Br in the [PbBr₆]⁴⁻ octahedron. In (d), two 2p peaks of Ni are shown, located at 871 eV and 854 eV, corresponding to the 2p¹ / ² and 2p³ / ² orbitals, respectively. In summary, the metal-doped A₂BX₅ crystal produced in Example 1 is Ni-doped CsPb₂Br₅.

[0105] During storage, metal-doped A2BX5 crystals may undergo chemical reactions with moisture and oxygen in the air, leading to damage to their crystal structure and the generation of defects. These defects become recombination centers for charge carriers, making nonradiative recombination of photogenerated charge carriers more likely and reducing the probability of radiative recombination, thus lowering the PL peak.

[0106] From Example 1 and Comparative Examples 1-2, and Figure 3 and Figures 10-11 It can be seen that after being placed at room temperature for a period of time, Figure 10 and Figure 11 The peak value in comparison to Figure 1 The lower value indicates that the stability of Example 1 is higher than that of Comparative Examples 1 and 2. Meanwhile, as shown in Figure 2, the brightness of the metal-doped A2BX5 crystal in Example 1 under ultraviolet light is greater than that of Comparative Example 1. Therefore, compared to the amine-terminated metal-doped A2BX5 crystal prepared by ligand exchange, the metal-doped A2BX5 crystal of this example has a higher luminescence intensity.

[0107] Examples 1-3, Comparative Examples 1-2, and Figures 3-5 It is known that the molar ratio range of BX2 and metal chelating agent provided in this application can ensure the high stability of metal-doped A2BX5 crystals.

[0108] Examples 1, 4-5, and Comparative Examples 1-2, and Figure 3 , Figures 6-7 , Figure 11 It is known that the molar ratio of CX2, BX2 and AX provided in this application enables the production of metal-doped A2BX5 crystals with a high yield, and thus a high fluorescence intensity.

[0109] Examples 1, 6-7, and Comparative Examples 1-2, and Figures 8-9 It is understood that the metal chelating agent and the type of CX2 provided in this application can effectively improve the high stability of metal-doped A2BX5 crystals.

[0110] The photodetector and display device provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for preparing a metal-doped A2BX5 crystal, characterized in that, The method includes: A first mixture is provided, the first mixture comprising AX, BX2, CX2 and a first solvent; The first mixture is subjected to a first heating treatment to obtain a second mixed solution; A metal chelating agent is added to the second mixed solution to obtain a third mixed solution; A second solvent is added to the third mixed solution, and a second heat treatment is performed to obtain a metal-doped A2BX5 crystal, wherein C is doped in the A2BX5 crystal; Wherein, A is selected from at least one of cesium ion, formamidinium ion, methylammonium ion, n-octylammonium ion, phenylethylammonium ion, benzylammonium ion, and tert-butylammonium ion; B is selected from at least one of lead ion and tin ion; C is selected from at least one of manganese, iron, nickel, copper, zinc, aluminum, and molybdenum; X is selected from at least one of iodide ion, bromide ion, and chloride ion; and the metal chelating agent includes at least one of carboxylic acid chelating agents and organic polyphosphonic acid chelating agents.

2. The method for preparing metal-doped A2BX5 crystal according to claim 1, characterized in that, The carboxylic acid chelating agent includes at least one selected from m-4-pyridinecarboxylic acid, phthalic acid, trimesolic acid, terephthalic acid, and pyridine 3,5-dicarboxylic acid; and / or At least one of the organic polyphosphonic acid chelating agents 1,1'-bis(diphenylphosphine)ferrocene, hydroxyethylidene diphosphonic acid, and bis(triphenylphosphine)palladium dichloride; and / or, The AX includes CsCl, CsBr, CsI, CH3NH3Br, CH3(CH2)7NH3Cl, CH3(CH2)7NH3Cl; and / or, The BX2 includes at least one of PbCl2, PbBr2, PbI2, SnCl2, SnBr2, and SnI2; and / or, The CX2 includes at least one of NiBr2, NiI2, NiCl2, MoBr2, ZnBr2, and their hydrates.

3. The method for preparing metal-doped A2BX5 crystal according to claim 1, characterized in that, The molar ratio of CX2, BX2, and AX is (2-6):(1-3):1; optionally, the molar ratio of CX2, BX2, and AX is (3-5):(1.5-2.5):1; and / or, The molar ratio of BX2 to the metal chelating agent is (1-20):

1.

4. The method for preparing metal-doped A2BX5 crystal according to claim 1, characterized in that, The first solvent comprises at least one selected from dimethylformamide, γ-butyrolactone, dimethyl sulfoxide, and N,N-dimethylacetamide; and / or, The second solvent includes at least one selected from toluene, n-hexane, diethyl ether, trifluorotoluene, iodobenzene, sec-butanol, anisole, ethyl acetate, and methyl acetate; and / or, The metal-doped A2BX5 crystal includes at least one of Cs2PbBr5, Cs2SnCl5, (CH(NH2)2)2SnI5, and Cs2SbBr5.

5. The method for preparing metal-doped A2BX5 crystal according to claim 1, characterized in that, The temperature of the first heat treatment is 40℃~100℃; and / or, The first heat treatment also includes stirring at a speed of 200 rpm to 500 rpm; and / or, The temperature of the second heat treatment is 100℃~160℃; and / or, The second heat treatment also involves stirring at a speed of 100 rpm to 300 rpm; and / or, The pressure of the second heat treatment is 12 MPa to 30 MPa; and / or, The second heat treatment lasts for 30 minutes to 2 hours.

6. A metal-doped A2BX5 crystal, characterized in that, The metal-doped A2BX5 crystal is prepared by any one of the methods described in claims 1 to 5.

7. A thin film, characterized in that, The thin film contains a metal-doped A2BX5 crystal, which is the metal-doped A2BX5 crystal described in claim 6 above, or is prepared by any of the methods in claims 1 to 5 above.

8. A photodetector, characterized in that, The photodetector includes an anode, a functional layer, and a cathode stacked sequentially, wherein the functional layer is the thin film described in claim 7.

9. The metal-doped photodetector according to claim 8, characterized in that, The photodetector includes a first electrode, a hole functional layer, the functional layer, an electron functional layer, and a second electrode, which are stacked in sequence. Optionally, the average thickness of the first electrode is 30-40 nm; and / or, the average thickness of the hole functional layer is 20-80 nm; and / or, the average thickness of the electron functional layer is 20-80 nm; and / or, the average thickness of the second electrode is 30-40 nm.

10. The metal-doped photodetector according to claim 9, characterized in that, The first electrode and the second electrode independently comprise one or more of the following: a metal electrode, a silicon-carbon electrode, a doped or undoped metal oxide electrode, and a composite electrode; wherein, the material of the metal electrode is selected from at least one of Al, Ag, Cu, Mo, Au, Ba, Ca, and Mg; the material of the silicon-carbon electrode is selected from at least one of silicon, graphite, carbon nanotubes, graphene, and carbon fibers; the material of the doped or undoped metal oxide electrode is selected from at least one of ITO, FTO, ATO, AZO, GZO, IZO, MZO, and AMO; and the material of the composite electrode is selected from at least one of AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, TiO2 / Ag / TiO2, TiO2 / Al / TiO2, ZnS / Ag / ZnS, ZnS / Al / ZnS, TiO2 / Ag / TiO2, and TiO2 / Al / TiO2. And / or, the electronic functional layer includes an electron transport layer and / or an electron injection layer, wherein the materials of the electron transport layer and the electron injection layer are each independently selected from zinc oxide, titanium dioxide, tin dioxide, aluminum oxide, calcium oxide, silicon dioxide, gallium oxide, zirconium oxide, nickel oxide, zirconium trioxide, and C. 60 C 70 At least one of Bphen, BCP, Alq3, and PCBM; And / or, the hole functional layer includes a hole transport layer and / or a hole injection layer, wherein the materials of the hole transport layer and the hole injection layer are each independently selected from at least one of PEDOT:PSS, NPB, TCTA, TAPC, CBP, P3HT, spiro-OMeTAD, and MoO3.

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