A high-quality organic-inorganic hybrid perovskite material and its preparation method

Abstract

This invention belongs to the field of semiconductor materials technology and discloses a high-quality organic-inorganic hybrid perovskite material and its preparation method. This invention involves simultaneously doping Co into a CH3NH3PbX3 (where X is Cl, Br, or I) perovskite material. 2+ and H2NCHNH2 + Ions, of which Co 2+ Ions occupying B lattice sites in perovskite enhance the perovskite lattice and reduce intrinsic and grain boundary defects in perovskite materials; H2NCHNH2 + Ions occupying the A lattice sites of perovskite suppress Co doping. 2+ The lattice distortion caused by this reduces Co 2+ Ion defects. Therefore, (CH3NH3) 1‑a (H2NCHNH2) a Pb 1‑b Co b X3(0

Description

Technical Field

[0001] This invention belongs to the field of semiconductor materials technology, specifically relating to a high-quality organic-inorganic hybrid perovskite material and its preparation method. Background Technology

[0002] Organic-inorganic hybrid perovskite (abbreviated as perovskite, its molecular formula is ABX3, where A is CH3NH3) + H2NCHNH2 + Cs + Etc., B is Pb 2+ Sn 2+ Etc., X is Cl - ,Br - I - ( ) is a direct bandgap semiconductor material, which has a high optical absorption coefficient (>10). 4 cm -1 Perovskite materials, with their long carrier lifetime (>1.0 μs), long carrier diffusion length (>1.0 μm), and ability to be prepared at low temperatures, are crucial semiconductor materials for fabricating low-cost and high-performance optoelectronic devices such as solar cells, photodetectors, and light-emitting diodes. However, the poor stability of perovskite optoelectronic devices severely hinders their commercial application. Essentially, the easy decomposition and ion migration of perovskite materials under conditions such as water vapor, oxygen, ultraviolet light, and high temperatures are the main reasons for the poor stability of perovskite optoelectronic devices. Physical isolation and heat dissipation techniques can reduce the influence of water vapor, oxygen, and high temperatures, while photoinduced decomposition and ion migration are inherent properties of perovskite materials, closely related to intrinsic defects and grain boundary defects. It is generally believed that only by fabricating high-quality, low-defect perovskite materials can the problem of poor stability in perovskite materials and devices be fundamentally solved. Therefore, designing and fabricating high-quality perovskite materials is of great significance for the development and promotion of the commercial application of perovskite optoelectronic devices. Summary of the Invention

[0003] To address some shortcomings of existing perovskite materials, this invention provides a high-quality organic-inorganic hybrid perovskite material and its preparation method.

[0004] The molecular formula of the high-quality organic-inorganic hybrid perovskite material is (CH3NH3). 1-a (H2NCHNH2) a Pb 1- b Co b X3, where X is one or more combinations of Cl, Br or I, and a and b are both positive numbers less than 1.

[0005] The preparation method of the high-quality organic-inorganic hybrid perovskite material includes the following steps:

[0006] Step 1: Prepare CH3NH3X / PbX2 precursor solution:

[0007] CH3NH3X and PbX2 materials were mixed and dissolved in a mixed solution of dimethylformamide and dimethyl sulfoxide, and stirred thoroughly to form a CH3NH3X / PbX2 precursor solution;

[0008] Step 2, Configure Co 2+ Salt precursor solution:

[0009] A certain amount of one or more of CoX2, ZIF-67, or cobalt acetate is dissolved in the CH3NH3X / PbX2 precursor solution obtained in step 1, and the mixture is stirred and allowed to stand sequentially to form Co. 2+ Co ions with a concentration of 0.01–0.10 mol / L 2+ Salt precursor solution;

[0010] Step 3: Prepare the perovskite spin coating solution:

[0011] A certain amount of H2NCHNH2X material was dissolved in the Co obtained in step 2. 2+ In the salt precursor solution, stir thoroughly and let stand to form a perovskite spin-coating solution with a H2NCHNH2X concentration of 0.02–0.20 mol / L;

[0012] Step 4: Pre-treat the substrate;

[0013] Step 5: Using an anti-solvent crystallization one-step spin-coating method, spin-coat the perovskite spin coating solution from Step 3 onto the substrate pretreated in Step 4; after spin-coating, perform thermal annealing: first anneal at 70–85°C for 1–10 minutes, then anneal at 90–180°C for 9–30 minutes; to obtain (CH3NH3). 1-a (H2NCHNH2) a Pb 1-b Co b X3, where X is one or more combinations of Cl, Br or I, a is the molar percentage of H2NCHNH2 in the total amount of CH3NH3 and H2NCHNH2 in the perovskite spin coating solution, and b is the molar percentage of Co in the total amount of Co and Pb in the perovskite spin coating solution.

[0014] Preferably, in step 1, the molar ratio of CH3NH3X to PbX2 is 0.9:1 to 1.1:1, and the concentrations of CH3NH3X and PbX2 are both 0.2 to 1.4 mol / L.

[0015] Preferably, in step 1, the volume ratio of dimethylformamide to dimethyl sulfoxide is 4:1 to 9:1.

[0016] Preferably, in step 4, the substrate is ITO glass or FTO glass.

[0017] Preferably, in step 4, the pretreatment steps of the substrate include:

[0018] Step A1: Sequentially use acetone, ethanol, and deionized water to ultrasonically clean the substrate for 4 - 15 minutes to remove impurities and oil stains on the surface of the substrate;

[0019] Step A2: Blow dry the water droplets on the surface of the substrate with nitrogen;

[0020] Step A3: Place the substrate in an oven to further dry the remaining water droplets on the surface of the substrate;

[0021] Step A4: Place the substrate in an oxygen plasma machine or an ozone cleaning machine and clean for 10 - 20 minutes to enhance the hydrophilicity of the substrate surface.

[0022] Preferably, in step 5, the anti - solvent is one or a combination of ethyl acetate, toluene, and chlorobenzene.

[0023] The use of the organic - inorganic hybrid perovskite material prepared by the present invention for preparing perovskite optoelectronic devices.

[0024] The beneficial effects of the present invention are:

[0025] In the perovskite CH3NH3PbX3 material of the present invention, Co 2+ and H2NCHNH2 + ions are doped to form a high - quality (CH3NH3) 1-a (H2NCHNH2) a Pb 1-b Co b X3 (0 < a < 1, 0 < b < 1) perovskite material. In this material, Co 2+ ions occupy the B lattice site of the perovskite structure to enhance the perovskite lattice, effectively reducing the intrinsic defects and grain boundary defects of Pb vacancies and X vacancies in the perovskite material; H2NCHNH2 + ions occupy the A lattice site of the perovskite structure to inhibit the lattice distortion caused by the doped Co 2+ ions, effectively reducing the formation of Co 2+ ion interstitial defects. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is (CH3NH3) 1-a (H2NCHNH2) a Pb1-b Co b Schematic diagram of the preparation process of X3 perovskite material (where DMF and DMSO are dimethylformamide and dimethyl sulfoxide, respectively); a-Preparation process of perovskite spin coating solution, b-Perovskite (CH3NH3) 1-a (H2NCHNH2) a Pb 1-b Co b The spin coating process of X3 thin film;

[0027] Figure 2 It is (CH3NH3) 1-a (H2NCHNH2) a Pb 1-b Co b Schematic diagram of the structure of X3 perovskite material;

[0028] Figure 3 It is (CH3NH3) 0.98 (H2NCHNH2) 0.02 Pb 0.99 Co 0.01 Photographs of I3 perovskite material;

[0029] Figure 4 It is (CH3NH3) 0.98 (H2NCHNH2) 0.02 Pb 0.99 Co 0.01 SEM images of I3 perovskite material; a-surface, b-section;

[0030] Figure 5 It is (CH3NH3)Pb 0.99 Co 0.01 I3 and (CH3NH3) 0.98 (H2NCHNH2) 0.02 Pb 0.99 Co 0.01 XRD results of I3 perovskite material. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0032] (CH3NH3) 1-a (H2NCHNH2) a Pb 1-b Co b The preparation process of X3 perovskite material is as follows: Figure 1 As shown, the structure is as follows Figure 2 As shown;

[0033] Example 1:

[0034] (1) Pretreatment of ITO glass substrate;

[0035] Take ITO glass with dimensions of 15mm × 15mm;

[0036] The ITO glass was ultrasonically cleaned for 5 minutes in sequence with acetone, ethanol and deionized water to remove impurities and oil stains from the surface of the ITO glass.

[0037] Use a nitrogen gun to dry the water droplets on the ITO glass surface;

[0038] Dry the residual water droplets on the ITO glass surface using an oven (temperature 60℃);

[0039] Clean the ITO glass with an oxygen plasma machine for 15 minutes to increase the hydrophilicity of the ITO glass surface;

[0040] (2) Preparation of CH3NH3I / PbI2 precursor solution. CH3NH3I and PbI2 materials were mixed at a molar ratio of 1:1 and dissolved in a mixed solution of dimethylformamide and dimethyl sulfoxide (volume ratio of the two is 4:1). The mixture was stirred to obtain a 1.3 mol / L CH3NH3I / PbI2 precursor solution.

[0041] (3) The ZIF-67 material was dissolved in the CH3NH3I / PbI2 precursor solution, stirred at room temperature for 12 hours, and then allowed to stand at room temperature for 6 hours to obtain a ZIF-67 concentration of 3.0 mg / mL. 2+ Salt precursor solution;

[0042] (4) Dissolve H2NCHNH2I material in Co 2+ In the salt precursor solution, the mixture was stirred at room temperature and allowed to stand to obtain a perovskite spin-coating solution with an H2NCHNH2I concentration of 4.6 mg / mL.

[0043] (5) Take 80 μL of perovskite spin coating liquid and uniformly drop it onto the pretreated ITO substrate for spin coating. The spin coating parameters are: rotation speed of 5000 r / min, spin coating time of 30 s, and add 400 μL of ethyl acetate at the 8th second of spin coating to obtain perovskite liquid film.

[0044] (6) The perovskite liquid film was placed on a hot plate and annealed at 70°C for 1 minute and 100°C for 10 minutes in sequence to obtain (CH3NH3). 0.98 (H2NCHNH2) 0.02 Pb 0.99 Co 0.01 I3 perovskite thin film materials;

[0045] Figure 2 It shows (CH3NH3).0.98 (H2NCHNH2) 0.02 Pb 0.99 Co 0.01 The structural diagram of I3 perovskite material shows that Co occupies the Pb lattice sites and H2NCHNH2 occupies the center position of the perovskite cube.

[0046] Figure 3 It shows (CH3NH3). 0.98 (H2NCHNH2) 0.02 Pb 0.99 Co 0.01 The photo of the I3 perovskite thin film shows that it is dark black, uniform in color, and has high light absorption.

[0047] Figure 4 It shows (CH3NH3). 0.98 (H2NCHNH2) 0.02 Pb 0.99 Co 0.01 SEM images of the surface and cross-section of the I3 perovskite thin film material show that its surface is dense, without pores, with large grain size and uniform thickness.

[0048] Figure 5 It shows (CH3NH3)Pb 0.99 Co 0.01 I3 and (CH3NH3) 0.98 (H2NCHNH2) 0.02 Pb 0.99 Co 0.01 The XRD curve of the I3 perovskite thin film material shows that H2NCHNH2 was incorporated. + The ions did not alter the crystal structure of the perovskite material, while mitigating the effects of Co doping. 2+ Compressive strain caused by ions.

[0049] Example 2:

[0050] (1) Pretreatment of ITO glass substrate;

[0051] Take ITO glass with dimensions of 15mm × 15mm;

[0052] The ITO glass was ultrasonically cleaned for 5 minutes in sequence with acetone, ethanol and deionized water to remove impurities and oil stains from the surface of the ITO glass.

[0053] Use a nitrogen gun to dry the water droplets on the ITO glass surface;

[0054] Dry the residual water droplets on the ITO glass surface using an oven (temperature 60℃);

[0055] Clean the ITO glass with an oxygen plasma machine for 15 minutes to increase the hydrophilicity of the ITO glass surface;

[0056] (2) Preparation of CH3NH3I / PbI2 precursor solution. CH3NH3I and PbI2 materials were mixed at a molar ratio of 1:1 and dissolved in a mixed solution of dimethylformamide and dimethyl sulfoxide (volume ratio of the two is 4:1). The mixture was stirred to obtain a 1.3 mol / L CH3NH3I / PbI2 precursor solution.

[0057] (3) The ZIF-67 material was dissolved in the CH3NH3I / PbI2 precursor solution, stirred at room temperature for 12 hours, and then allowed to stand at room temperature for 6 hours to obtain a Co solution with a ZIF-67 concentration of 6.0 mg / mL. 2+ Salt precursor solution;

[0058] (4) Dissolve H2NCHNH2I material in Co 2+ In the salt precursor solution, the mixture was stirred at room temperature and allowed to stand to obtain a perovskite spin-coating solution with an H2NCHNH2I concentration of 9.2 mg / mL.

[0059] (5) Take 80 μL of perovskite spin coating liquid and uniformly drop it onto the pretreated ITO substrate for spin coating. The spin coating parameters are: rotation speed of 5000 r / min, spin coating time of 30 s, and add 400 μL of ethyl acetate at the 8th second of spin coating to obtain perovskite liquid film.

[0060] (6) The perovskite liquid film was placed on a hot plate and annealed at 70°C for 1 minute and 100°C for 10 minutes in sequence to obtain (CH3NH3). 0.96 (H2NCHNH2) 0.04 Pb 0.98 Co 0.02 I3 perovskite thin film materials;

[0061] Example 3:

[0062] (1) Pretreatment of ITO glass substrate;

[0063] Take ITO glass with dimensions of 15mm × 15mm;

[0064] The ITO glass was ultrasonically cleaned for 5 minutes in sequence with acetone, ethanol and deionized water to remove impurities and oil stains from the surface of the ITO glass.

[0065] Use a nitrogen gun to dry the water droplets on the ITO glass surface;

[0066] Dry the residual water droplets on the ITO glass surface using an oven (temperature 60℃);

[0067] Cleaning ITO glass with a UV ozone generator for 20 minutes increases the hydrophilicity of the ITO glass surface.

[0068] (2) Preparation of CH3NH3Br / PbBr2 precursor solution. CH3NH3Br and PbBr2 materials were mixed at a molar ratio of 1.05:1 and dissolved in a mixed solution of dimethylformamide and dimethyl sulfoxide (volume ratio of the two is 8:1). The mixture was stirred to obtain a 0.4 mol / L CH3NH3Br / PbBr2 precursor solution.

[0069] (3) ZIF-67 material was dissolved in CH3NH3Br / PbBr2 precursor solution, stirred at room temperature for 12 hours, and then allowed to stand at room temperature for 6 hours to obtain Co with a ZIF-67 concentration of 1.39 mg / mL. 2+ Salt precursor solution;

[0070] (4) Dissolve the H2NCHNH2Br material in Co 2+ In the salt precursor solution, the mixture was stirred thoroughly at room temperature and allowed to stand to obtain a perovskite spin-coating solution with a H2NCHNH2Br concentration of 1.5 mg / mL.

[0071] (5) 80 μL of perovskite spin-coating solution was dropped onto ITO to prepare a perovskite film by spin coating. The spin coating parameters were as follows: the first stage rotation speed was 500 r / min and the spin coating time was 5 s; the second stage rotation speed was 3000 r / min and the spin coating time was 20 s. 300 μL of toluene / ethyl acetate mixed solution (volume ratio of 1:2) was dropped into the second second of the second stage spin coating to obtain a perovskite liquid film.

[0072] (6) The perovskite liquid film was placed on a hot plate and annealed at 80°C for 1 minute and 120°C for 15 minutes in sequence to obtain (CH3NH3). 0.97 (H2NCHNH2) 0.03 Pb 0.985 Co 0.015 Br3 perovskite thin film material.

[0073] The embodiments described above are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A high-quality organic-inorganic hybrid perovskite material, characterized in that, The molecular formula is (CH3NH3). 1-a (H2NCHNH2) a Pb 1-b Co b X3, where X is one or more combinations of Cl, Br and I, and a and b are both positive numbers less than 1.

2. The method for preparing high-quality organic-inorganic hybrid perovskite material according to claim 1, characterized in that, Includes the following steps: Step 1: Prepare CH3NH3X / PbX2 precursor solution: CH3NH3X and PbX2 materials were mixed and dissolved in a mixed solution of dimethylformamide and dimethyl sulfoxide, and stirred thoroughly to form a CH3NH3X / PbX2 precursor solution; Step 2, Configure Co 2+ Salt precursor solution: One or more of CoX2, ZIF-67, or cobalt acetate are dissolved in the CH3NH3X / PbX2 precursor solution obtained in step 1, and the mixture is stirred and allowed to stand sequentially to form Co. 2+ Co ions with a concentration of 0.01–0.10 mol / L 2+ Salt precursor solution; Step 3: Prepare the perovskite spin coating solution: The H2NCHNH2X material was dissolved in the Co obtained in step 2. 2+ In the salt precursor solution, stir thoroughly and let stand to form a perovskite spin-coating solution with a H2NCHNH2X concentration of 0.02–0.20 mol / L; Step 4: Pre-treat the substrate; Step 5: Using an anti-solvent crystallization one-step spin-coating method, spin-coat the perovskite spin coating solution from Step 3 onto the substrate pretreated in Step 4; after spin-coating, perform thermal annealing: first anneal at 70–85°C for 1–10 minutes, then anneal at 90–180°C for 9–30 minutes; to obtain (CH3NH3). 1-a (H2NCHNH2) a Pb 1-b Co b X3, Where X is one or more combinations of Cl, Br or I, a is the molar percentage of H2NCHNH2 in the total amount of CH3NH3 and H2NCHNH2 in the perovskite spin coating solution, and b is the molar percentage of Co in the total amount of Co and Pb in the perovskite spin coating solution.

3. The preparation method according to claim 2, characterized in that, In step 1, the molar ratio of CH3NH3X to PbX2 is 0.9:1 to 1.1:1, and the concentrations of CH3NH3X and PbX2 are both 0.2 to 1.4 mol / L.

4. The preparation method according to claim 2, characterized in that, In step 1, the volume ratio of dimethylformamide to dimethyl sulfoxide is 4:1 to 9:

1.

5. The preparation method according to claim 2, characterized in that, In step 4, the substrate is ITO glass or FTO glass.

6. The preparation method according to claim 2, characterized in that, Step 4, the substrate pretreatment step includes the following steps: Step A1: Use acetone, ethanol and deionized water in sequence to perform ultrasonic cleaning on the substrate for 4-15 minutes to remove impurities and oil stains from the substrate surface. Step A2: Dry the water droplets on the substrate surface with nitrogen gas; Step A3: Place the substrate in an oven to further dry any remaining water droplets on the substrate surface; Step A4: Place the substrate in an oxygen plasma cleaner or ozone cleaner for 10-20 minutes to enhance the hydrophilicity of the substrate surface.

7. The preparation method according to claim 2, characterized in that, In step 5, the antisolvent is one or a combination of ethyl acetate, toluene, and chlorobenzene.

8. The use of the organic-inorganic hybrid perovskite material according to claim 1 in the preparation of perovskite optoelectronic devices.

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