Preparation method of stable ABX3 type perovskite semiconductor material

Abstract

The invention discloses a preparation method of a stable ABX3 type perovskite semiconductor material. According to the invention, the EDTA-yM is introduced into the ABX3 type perovskite crystal to regulate and control crystal lattices, so that the perovskite thin film material is stabilized, and the obtained ultrahigh-stability perovskite thin film is compact and flat in surface. According to the method for introducing the EDTA-yM into the perovskite crystal material, the EDTA-yM can be directly introduced into the precursor, the EDTA-yM can enter perovskite crystal lattices in the solvent removal process, the EDTA-yM can also be directly introduced into a perovskite thin film in a solid diffusion or gasification mode, and the requirement for production facilities is lowered. The ABX3 type perovskite with high quality and ultrahigh stability can be widely applied to the photoelectric fields of batteries, luminescence, detectors and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor photoelectric materials, and in particular to a stable ABX 3 Preparation method of perovskite semiconductor material. Background Art

[0002] In recent years, ABX 3 Halide perovskites are widely used in optoelectronic fields such as solar cells, luminescence, and detectors due to their long carrier diffusion length, high light absorption efficiency, and adjustable band gap. However, the poor stability of these perovskite materials has become the main bottleneck for the industrialization of perovskite optoelectronic devices.

[0003] Early methylamine lead iodide (MAPbI 3 ) The volatile methylamine cation (MA) in the perovskite + ) makes its chemical stability poor (J.Am.Chem.Soc., 2009, 131, 6050).

[0004] Replacement MA + The chemically stable formamidinium lead iodide / cesium lead iodide (FAPbI 3 / CsPbI 3 ) perovskite, which solves the problem of poor chemical stability of halide perovskite materials (Chem. Rev., 2019, 119, 3036).

[0005] Compared with MAPbI 3 ,FAPB 3 (1.49eV) is an ideal light-absorbing layer material for single-junction solar cells; CsPbI 3 (~1.7eV) has shown great application prospects in silicon-based perovskite photovoltaics and X-ray detection. However, this type of perovskite has poor phase stability due to the metastable lattice, that is, it is easy to transform from a black phase with octahedrons sharing vertices with photoelectric activity to a yellow phase with octahedrons sharing faces / edges and no photoelectric activity.

[0006] Solving the key scientific problem of poor perovskite stability caused by the metastable state of the perovskite lattice is crucial to promoting the industrial development of perovskite-based optoelectronic devices (photovoltaic cells, photodetectors, and light-emitting diodes, etc.). Summary of the invention

[0007] In view of the above-mentioned deficiencies in the prior art, the present invention provides a preparation method by introducing a certain amount of ethylenediaminetetraacetic acid alkali metal compound (EDTA-yM, where M = Na, K, Cs, and y represents the number of atoms of M in each molecule) into the perovskite crystal to regulate the metastable perovskite lattice, thereby obtaining a highly stable and high-quality perovskite thin film material.

[0008] A stable ABX 3 A method for preparing a type perovskite semiconductor material comprises the following steps:

[0009] (1) The halide salt AX and the halide metal BX 2 Mixing with an organic salt and dissolving in a solvent to obtain a precursor solution;

[0010] (2) mixing an ethylenediaminetetraacetic acid alkali metal compound with a precursor solution, heating the mixture for reaction, coating the resulting solution on a substrate after the reaction, and removing the solvent to obtain a perovskite thin film material, namely the stable ABX 3 Type perovskite semiconductor materials,

[0011] Alternatively, the precursor solutions are first mixed, heated for reaction, the resulting solution is coated on a substrate after the reaction, the solvent is removed to obtain a perovskite film, and then the ethylenediaminetetraacetic acid alkali metal compound is introduced into the perovskite film by solid-state diffusion or vapor diffusion to obtain the stable ABX 3 Type perovskite semiconductor materials,

[0012] Wherein, X represents a halogen element, which is at least one of the following: iodine, bromine;

[0013] A is at least one of the following: cesium, methylamine, formamidine;

[0014] B is at least one of the following: lead, tin;

[0015] The organic salt is at least one of the following: dimethylamine hydroiodide, potassium chloride and ammonia.

[0016] Preferably, in step (1), the halide salt AX, the halide metal BX 2 The molar ratio of the organic salt to the halogenated salt AX is 1:1:x, wherein 0<x≤2. Most preferably, in step (1), the halogenated salt AX and the metal halide BX 2 The molar ratio of the organic salt is 1:1:1.

[0017] Preferably, the solvent is at least one of N,N-dimethylformamide or dimethyl sulfoxide.

[0018] Preferably, in step (2), the molar ratio of the ethylenediaminetetraacetic acid alkali metal compound to the halide salt AX in the precursor solution is z:1, wherein 0.01≤z≤0.02.

[0019] Preferably, in step (2), the heating temperature of the heating reaction is 30 to 210° C., and the time is 1 to 60 min. Most preferably, in step (2), the heating temperature of the heating reaction is 100° C., and the time is 20 min.

[0020] Preferably, the ethylenediaminetetraacetic acid alkali metal compound is at least one of the following or has a similar structure: disodium ethylenediaminetetraacetate, dipotassium ethylenediaminetetraacetate, tripotassium ethylenediaminetetraacetate.

[0021] Preferably, in step (2), the coating method is at least one of the following: spin coating, spraying, pulling, and dipping.

[0022] Preferably, in step (2), the solvent is removed by heating for volatilization at a temperature of 210° C. for 5 min.

[0023] The present invention also provides a stable ABX prepared by the preparation method 3 Type perovskite semiconductor materials.

[0024] The present invention also provides the stable ABX 3 Application of perovskite semiconductor materials in the preparation of optoelectronic devices such as solar cells, light-emitting diodes or photodetectors.

[0025] The present invention is provided by ABX 3 EDTA-yM is introduced into the perovskite crystal to regulate the lattice, thereby stabilizing the perovskite film material. The ultra-high stable perovskite film obtained is dense and has a smooth surface. The principle is that EDTA-yM can pass CO, C=O and M + The ions act on the perovskite lattice at the same time and regulate the lattice, ultimately stabilizing ABX 3 Perovskite crystal material.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The present invention only introduces a very small amount of low-cost EDTA-yM into the perovskite material to achieve an order of magnitude improvement in the stability of the perovskite material. The preparation method is simple and easy to control, and is convenient for industrial production.

[0028] 2. The method of introducing EDTA-yM into perovskite crystal materials of the present invention can be carried out by directly introducing EDTA-yM into the precursor, allowing EDTA-yM to enter the perovskite lattice during the solvent removal process, or by directly introducing EDTA-yM into the perovskite film by solid-state diffusion or vaporization diffusion, thereby reducing the requirements for production facilities.

[0029] 3. ABX with high quality and ultra-high stability produced by the method of the present invention 3 Type perovskite can be widely used in optoelectronic fields such as batteries, luminescence, and detectors. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is the X-ray diffraction pattern of the material obtained in Example 1.

[0031] Figure 2 This is the UV-visible spectroscopic spectrum of the material obtained in Example 1.

[0032] Figure 3 This is the surface morphology of the material obtained in Example 1.

[0033] Figure 4 This is the X-ray diffraction pattern of the material obtained in Example 1 after aging at 100°C for 100 hours.

[0034] Figure 5 This is the X-ray diffraction pattern of the material obtained in Comparative Example 1.

[0035] Figure 6 This is the X-ray diffraction pattern of the material obtained in Comparative Example 1 after aging at 100°C for 100 hours.

[0036] Figure 7 This is the X-ray diffraction pattern of the material obtained in Example 2 after aging at 100°C for 100 hours.

[0037] Figure 8 This is the X-ray diffraction pattern of the material obtained in Example 3 after aging at 100°C for 100 hours. DETAILED DESCRIPTION

[0038] Example 1

[0039] This embodiment relates to a method of introducing EDTA-2Na (ethylenediaminetetraacetic acid disodium) into CsPbI 3 Crystal material, thus obtaining CsPbI with ultra-high stability 3 Perovskite materials:

[0040] 1) 0.324g of lead iodide, 0.182g of cesium iodide and 0.121g of dimethylamine hydroiodide (molecular formula C 2 H 7 N·HI) was dissolved in 1 mL of DMF to obtain a precursor solution A; the molar ratio of the lead iodide, cesium iodide and dimethylamine hydroiodide was 1:1:1.

[0041] 2) Add 0.0029 g EDTA-2Na, i.e. CsI:PbI to the precursor solution A obtained in step 1) 2 The molar ratio of EATA-2Na was 1:1:0.012, and the solution was heated at 100°C for 20 min to obtain solution B.

[0042] 3) The solution B obtained in step 2) is spin-coated onto the FTO substrate at 3000 rpm for 30 seconds, and the spin-coated substrate is annealed at 210° C. for 5 minutes to obtain a perovskite film with ultra-high stability.

[0043] The final product prepared in this example was tested.

[0044] Figure 1 is the X-ray diffraction pattern of Example 1, from which it can be concluded that the lattice-controlled CsPbI obtained in Example 1 3 The perovskite film has good crystallinity.

[0045] Figure 2 This is the UV-visible light spectroscopic spectrum of Example 1, from which it can be seen that the perovskite film obtained in Example 1 has obvious characteristic absorption, and the absorption edge is 737nm.

[0046] Figure 3 The scanning electron microscope photo of Example 1 shows that the lattice-controlled CsPbI 3 The surface of the perovskite film is dense and has high coverage.

[0047] The perovskite film obtained in this example was aged at 100°C for 100 hours and then subjected to X-ray diffraction testing. The results are as follows: Figure 4 As shown, it can be seen that the perovskite film still maintains a high-purity perovskite crystal phase after 100 hours of aging.

[0048] Comparative Example 1

[0049] The method is the same as in Example 1, except that EDTA-2Na is not introduced in step 1), and the obtained film ( Figure 5 ) At 100℃, after 48 hours, the film undergoes a phase change ( Figure 6 ).

[0050] Figure 5 The original X-ray diffraction pattern of the perovskite film before aging in Comparative Example 1, from which it can be concluded that the CsPbI 3 The perovskite film has good crystallinity; Figure 6 This is the X-ray diffraction pattern of the perovskite film after aging at 100°C for 100 hours. At this time, the perovskite phase has completely transformed into a non-perovskite yellow phase.

[0051] Example 2

[0052] The method is the same as that in Example 1, except that the EDTA-2Na used in step 2) is adjusted to EDTA-2K (ethylenediaminetetraacetic acid dipotassium), and the addition molar ratio is the same as that in Example 1. A high-quality and ultra-high stability perovskite thin film material is still obtained, and the material still maintains a high-purity crystal phase characteristic for more than 100 hours at 100°C ( Figure 7 ).

[0053] Figure 7This is the X-ray spectrum of the aged perovskite film obtained in Example 2, from which it can be concluded that the aged perovskite film still maintains a high-purity perovskite crystal phase.

[0054] Example 3

[0055] The method is the same as in Example 1, except that the mass of EDTA-2Na used in step 2) is 0.0059 g, i.e., CsI:PbI 2 ∶EDTA-2Na molar ratio is 1:1:0.025, and high-quality and ultra-high stability perovskite thin film materials are still obtained ( Figure 8 ).

[0056] Figure 8 This is the X-ray spectrum of the aged perovskite film obtained in Example 3, from which it can be concluded that the aged perovskite film still maintains a high-purity perovskite crystal phase.

Claims

1. A method for preparing a stable ABX3 type perovskite semiconductor material, characterized in that: The following steps are involved: (1) mixing a halide salt AX, a halide metal BX2 and an organic salt, and dissolving them in a solvent to obtain a precursor solution; (2) mixing an ethylenediaminetetraacetic acid alkali metal compound with a precursor solution, heating the mixture for reaction, coating the resulting solution on a substrate after the reaction, and removing the solvent to obtain a perovskite film material, namely the stable ABX3-type perovskite semiconductor material. Alternatively, the precursor solutions are first mixed, heated for reaction, the resulting solution is coated on a substrate after the reaction, the solvent is removed to obtain a perovskite film, and then the ethylenediaminetetraacetic acid alkali metal compound is introduced into the perovskite film by solid-state diffusion or vapor diffusion to obtain the stable ABX3-type perovskite semiconductor material. Wherein, X represents a halogen element, which is at least one of the following: iodine, bromine; A is at least one of the following: cesium, methylamine, formamidine; B is at least one of the following: lead, tin; The organic salt is at least one of the following: dimethylamine hydroiodide, potassium chloride and ammonia.

2. The preparation method according to claim 1, characterized in that: In step (1), the molar ratio of the halide salt AX, the halide metal BX2 and the organic salt is 1:1:x, wherein 0<x≤2.

3. The preparation method according to claim 1, characterized in that: The solvent is at least one of N,N-dimethylformamide and dimethyl sulfoxide.

4. The preparation method according to claim 1, characterized in that: In step (2), the molar ratio of the ethylenediaminetetraacetic acid alkali metal compound to the halide salt AX in the precursor solution is z:1, wherein 0.01≤z≤0.

02.

5. The preparation method according to claim 1, characterized in that: In step (2), the heating temperature of the heating reaction is 30 to 210° C. and the time is 1 to 60 minutes.

6. The preparation method according to claim 1, characterized in that: The ethylenediaminetetraacetic acid alkali metal compound is at least one of the following or has a similar structure: disodium ethylenediaminetetraacetate, dipotassium ethylenediaminetetraacetate, tripotassium ethylenediaminetetraacetate.

7. The preparation method according to claim 1, characterized in that: In step (2), the coating method is at least one of the following: spin coating, spraying, pulling, and dipping.

8. The preparation method according to claim 1, characterized in that: In step (2), the solvent is removed by heating for volatilization at a temperature of 210° C. for a time of 5 to 7 minutes.

9. A stable ABX3 type perovskite semiconductor material prepared by the preparation method according to any one of claims 1 to 8.

10. The stable ABX3-type perovskite semiconductor material according to claim 9 is used in various types of optoelectronic devices.

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