A preparation method and application of a perovskite film

Abstract

A preparation method and application of a perovskite film, which are used to solve the technical problem of how to have good stability while having good photoelectric conversion efficiency for the existing perovskite film. An inorganic halide salt containing bismuth, an N,N-dimethylformamide solution, hydroiodic acid and raw materials are used to prepare an intermediate material containing bismuth. Using this intermediate material as a raw material, together with an inorganic halide salt containing lead, cesium iodide and an N,N-dimethylformamide solution as raw materials, a precursor solution is prepared. The perovskite film prepared from this precursor solution has a perovskite crystal structure of ABX3. In the perovskite film of the present invention, the A site is occupied by CS and DMA, and the B site is occupied by Pb and Bi. The perovskite film in the present invention has good stability, and at the same time, the photoelectric conversion rate can exceed 10%. At the same time, a black perovskite thin film can be obtained at a temperature of 80 to 150 °C or below. The present invention is mainly used in the technical field of optoelectronic functional materials and devices.

Description

Technical Field

[0001] The present invention relates to the technical field of optoelectronic functional materials and devices, and particularly relates to a preparation method and application of a perovskite film. Background Art

[0002] With the continuous development of technology, environmental pollution and energy crisis are intensifying day by day. Solar cells using solar energy as the energy source have attracted much attention due to their outstanding advantages such as cleanness, high efficiency, and sustainability. As the leader of the third-generation solar cells

[0003] - the development of organic / inorganic hybrid perovskite solar cells is the most rapid; as an optoelectronic material, perovskite has a large spectral absorption intensity and a wide spectral absorption range, and can efficiently absorb most of the energy in solar energy.

[0004] The photoelectric conversion efficiency of existing solar cells made of α-CsxDMF1-XPbIz1Brz2Cl3-z1-z2 films prepared with lead-containing inorganic halides exceeds 16%. The lead-containing inorganic halides are mainly lead iodide, lead bromide, and lead chloride. By adjusting the proportions of the three elements Cl, Br, and I in the lead-containing inorganic halide in the perovskite material, the absorption intensity and absorption range of the material for sunlight can be well adjusted. The existing technology reveals that α-CsxDMF prepared by adjusting the binary blend of Cl, Br, and I 1-X PbI z1 Br z2 Cl 3-z1-z2 films also have a high photoelectric conversion efficiency, but their stability is poor, and they are very easy to transform into CsxDMF without photovoltaic activity at room temperature 1-X PbI z1 Br z2 Cl 3-z1-z2 films, and a black perovskite film can only be formed under conditions above 200 °C.

[0005] Regarding the perovskite photovoltaic cell of the ternary blend system, the patent with the publication number "CN104332560B" discloses that by synthesizing methylammonium iodide and methylammonium bromide, adjusting the molar ratio with PbCl 2 , PbBr 2 , PbI 2 and then dissolving them in N,N-dimethylformamide, and then using them as the light absorption layer material to prepare a photovoltaic cell. This MAPbBr y I 1-x-y Cl x cell relative to MAPbI 1-x Cl xThe battery has a certain increase in its open - circuit voltage by introducing Br, but both the short - circuit current and the conversion efficiency are greatly reduced. The highest efficiency of its ternary blend thin - film battery is 3.9%. Summary of the Invention

[0006] The object of the present invention is to address the deficiencies of the prior art and introduce a preparation method and application of a perovskite film to solve the technical problem of how to achieve good photoelectric conversion efficiency and good stability for existing perovskite films at the same time.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A preparation method of a perovskite film, comprising the following steps:

[0009] (1) Dissolve the bismuth - containing inorganic halide in an N,N - dimethylformamide solution;

[0010] (2) After the dissolution of the bismuth - containing inorganic halide in step (1) is completed, dropwise add hydroiodic acid and stir to obtain a pale - yellow precipitate;

[0011] (3) Vacuum - filter the pale - yellow precipitate in step (2) and transfer it to a container for washing with anhydrous ether;

[0012] (4) Transfer the washed pale - yellow precipitate in step (3) back to the container and place it in a vacuum drying oven at 60 °C for 12 hours to obtain an intermediate material;

[0013] (5) Weigh the intermediate material in step (4), weigh the lead - containing inorganic halide and cesium iodide, and then dissolve all the raw materials in an N,N - dimethylformamide solution to obtain a precursor solution;

[0014] (6) Deposit the precursor solution in step (5) on a substrate;

[0015] (7) Perform thermal annealing on the substrate in step (6) to form a black perovskite film;

[0016] Among them, the bismuth - containing inorganic halide is one or more mixtures of bismuth iodide, bismuth chloride, and bismuth bromide;

[0017] The lead - containing inorganic halide is lead iodide or a mixture of one or more of lead iodide, lead chloride, and lead bromide, and one of the mixtures is lead iodide;

[0018] The general formula of the intermediate material is: DMABiI z1 Br z2 Cl 3-z1-z2 ;

[0019] The general formula of the precursor solution is: CsxDMA 1-x Bi y Pb 1-y I z1 Br z2 Cl 3-z1-z2 , (x≠0, x≠1; y≠0, y≠1; z1≠0, z2≠0).

[0020] Furthermore, the bismuth-containing inorganic halide is bismuth bromide, and the lead-containing inorganic halide is lead iodide.

[0021] Furthermore, the thermal annealing treatment temperature in step (7) is 80 °C to 150 °C, and the annealing time is 5 min.

[0022] Furthermore, the mass ratio of the intermediate material, the lead-containing inorganic halide, and cesium iodide in step (5) is (1.5 - 2.5):(2 - 2.5):(0.5 - 1).

[0023] Furthermore, the mass of lead iodide in the mixture of lead-containing inorganic halides in step (1) is 80% to 90% of the total mass of the mixture.

[0024] Furthermore, in step (6), a spin coater is used to deposit the precursor solution on the substrate, and the rotation speed of the spin coater is 4000 revolutions per second, and the rotation time is 30 s.

[0025] Furthermore, the substrate is a conductive glass deposited with titanium oxide.

[0026] Furthermore, the vacuum drying gas in step (4) is one or a mixture of argon, nitrogen, and oxygen.

[0027] The perovskite film prepared by the method for preparing a perovskite film is applied to the preparation of solar cells, light-emitting diodes, photodiodes, lasers, thin-film transistors, photodetectors, or microsensor devices.

[0028] The beneficial effects of the present invention are:

[0029] A method for preparing a perovskite film and its application designed by the present invention uses a bismuth-containing inorganic halide, an N,N-dimethylformamide solution, hydroiodic acid, and a raw material to prepare a general formula: DMABiI z1 Br z2 Cl 3-z1-z2The intermediate material, and using this intermediate material as a raw material, together with an inorganic lead halide, cesium iodide, and an N,N-dimethylformamide solution, a precursor solution is prepared. The inorganic lead halide can be pure lead iodide, or a binary or ternary blend of lead iodide, lead chloride, and lead bromide. One of the blends is lead iodide. The general formula of the perovskite film prepared from this precursor solution is: CsxDMA 1-x BiyPb 1-y I z1 Br z2 Cl 3-z1-z2 , (x≠0, x≠1; y≠0, y≠1; z1≠0, z2≠0). The structure of the perovskite crystal is ABX 3 . In the perovskite film of the present invention, the A-site is occupied by CS and DMA, the B-site is occupied by Pb and Bi, and there are three cases for the X-site. The X-site is occupied by I and Br, or by I and Cl, or by I, Br, and Cl. The stability of the above perovskite film is tested, and its stability is good, and at the same time, the photoelectric conversion rate can exceed 10%. At the same time, a black perovskite thin film can be obtained at a temperature below 80-150°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a flow block diagram for the preparation of the perovskite film in the present invention;

[0031] Figure 2 is a stability test chart of the perovskite films prepared in Example 1 and Comparative Example 1. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] The following further illustrates the technical solutions in the present invention in conjunction with the attached Figure 1-2 drawings and embodiments.

[0033] Example 1

[0034] (1) Dissolve 2 g of bismuth bromide in 5 ml of N,N-dimethylformamide solution;

[0035] (2) After the bismuth bromide in step (1) is completely dissolved, gradually add 3 ml of hydroiodic acid dropwise and stir to obtain a uniform pale yellow precipitate;

[0036] (3) Vacuum filter the pale yellow precipitate in step (2) and transfer it to a container, and wash it with anhydrous ether to remove excess hydroiodic acid and N,N-dimethylformamide solution;

[0037] (4) Transfer the washed pale yellow precipitate in step (3) to a container again and place it in a vacuum drying oven filled with argon at 60°C for 12 hours to obtain the intermediate material;

[0038] At this time, the general formula of the intermediate material is: DMABiBr 3 ;

[0039] (5) Weigh 0.4 g of the intermediate material in step (4), and also weigh 0.32 g of lead iodide and 0.2 g of cesium iodide. Then dissolve the three raw materials in 1 ml of N,N-dimethylformamide solution to obtain a precursor solution;

[0040] At this time, the general formula of the precursor solution is: Cs 0.7 DMA 0.3 Bi 0.3 Pb 0.7 I 2.1 Br 0.9 ;

[0041] (6) Coat the precursor solution in step (5) on the conductive glass deposited with titanium oxide, and then place the substrate in a spin coater. The spin coater rotates at a speed of 4000 revolutions per second for 30 s;

[0042] (7) Place the substrate in step (6) on a hot plate at 80 °C for 5 min of thermal annealing treatment to form a black perovskite film.

[0043] Example 2

[0044] (1) Dissolve 1 g of bismuth bromide and 1 g of bismuth iodide in 5 ml of N,N-dimethylformamide solution;

[0045] (2) After the dissolution of bismuth bromide and bismuth iodide in step (1) is completed, add 3 ml of hydroiodic acid dropwise and stir to obtain a uniform pale yellow precipitate;

[0046] (3) Vacuum filter the pale yellow precipitate in step (2) and transfer it to a container for washing with anhydrous ether to remove excess hydroiodic acid and N,N-dimethylformamide solution;

[0047] (4) Transfer the washed pale yellow precipitate in step (3) to a container again and place it in a vacuum drying oven filled with oxygen at 60 °C for 12 hours to obtain an intermediate material;

[0048] At this time, the general formula of the intermediate material is: DMABiI 2.4 Br 0.6 ;

[0049] (6) Weigh 0.3 g of the intermediate material in step (4), and also weigh 0.37 g of lead iodide and 0.2 g of cesium iodide. Then dissolve the three raw materials in 1 ml of N,N-dimethylformamide solution to obtain a precursor solution;

[0050] At this time, the general formula of the precursor solution is: Cs0.8 DMA 0.2 Bi 0.2 Pb 0.8 I 2.4 Br 0.6 ;

[0051] (6) Coating the precursor solution in step (5) on the conductive glass deposited with titanium oxide, and then placing the substrate in a spin coater. The spin coater rotates at a speed of 4000 revolutions per second for 30 s;

[0052] (7) Placing the substrate in step (6) on a hot plate at 100 °C for 5 min of thermal annealing treatment to form a black perovskite film.

[0053] Example 3

[0054] (1) Dissolving 1 g of bismuth chloride and 1 g of bismuth iodide in 8 ml of N,N-dimethylformamide solution;

[0055] (2) After the bismuth bromide and bismuth iodide in step (1) are completely dissolved, adding 5 ml of hydroiodic acid dropwise and stirring to obtain a uniform pale yellow precipitate;

[0056] (3) Vacuum filtering the pale yellow precipitate in step (2) and transferring it to a container for washing with anhydrous ether to remove excess hydroiodic acid and N,N-dimethylformamide solution;

[0057] (4) Transferring the washed pale yellow precipitate in step (3) again to a container and drying it in a vacuum drying oven filled with argon, nitrogen and oxygen at 60 °C for 12 hours to obtain an intermediate material;

[0058] At this time, the general formula of the intermediate material is DMABiI 2.9 Cl 0.1 ;

[0059] (7) Weighing 0.5 g of the intermediate material in step (4), and weighing 0.27 g of lead iodide, 0.03 g of lead chloride, and 0.2 g of cesium iodide, and then dissolving the three raw materials in 1 ml of N,N-dimethylformamide solution to obtain a precursor solution;

[0060] At this time, the general formula of the precursor solution is: Cs 0.8 DMA 0.2 Bi 0.4 Pb 0.6 I 2.9 Cl 0.1 ;

[0061] (6) Coating the precursor solution in step (5) on the conductive glass deposited with titanium oxide, then placing the substrate in a spin coater, and the spin coater rotates at a speed of 4000 revolutions per second for 30 s;

[0062] (7) Placing the substrate in step (6) on a hot plate at 120 °C for 5 min of thermal annealing treatment to form a black perovskite film.

[0063] Example 4

[0064] (1) Dissolving 2 g of bismuth bromide, 1 g of bismuth chloride and 1 g of bismuth iodide in 10 ml of N,N-dimethylformamide solution;

[0065] (2) After the dissolution of bismuth bromide and bismuth iodide in step (1) is completed, adding 6 ml of hydroiodic acid dropwise and stirring to obtain a uniform pale yellow precipitate;

[0066] (3) Vacuum filtering the pale yellow precipitate in step (2) and transferring it to a container for washing with anhydrous ether to remove the excess hydroiodic acid and N,N-dimethylformamide solution;

[0067] (4) Transferring the washed pale yellow precipitate in step (3) again to a container and placing it in a vacuum drying oven filled with argon at 60 °C for 12 hours to obtain an intermediate material;

[0068] At this time, the general formula of the intermediate material is: DMABiI 1.2 Br 0.9 Cl 0.9 ;

[0069] (8) Weighing 0.8 g of the intermediate material in step (4), and weighing 0.8 g of lead iodide, 0.1 g of lead chloride, 0.1 g of lead bromide, 0.2 g of cesium iodide, and then dissolving the three raw materials in 2 ml of N,N-dimethylformamide solution to obtain a precursor solution;

[0070] At this time, the general formula of the precursor solution is: Cs 0.8 DMA 0.2 Bi 0.6 Pb 0.4 I 1.2 Br 0.9 Cl 0.9 ;

[0071] (6) Coating the precursor solution in step (5) on the conductive glass deposited with titanium oxide, then placing the substrate in a spin coater, and the spin coater rotates at a speed of 4000 revolutions per second for 30 s;

[0072] (7) Place the substrate in step (6) on a hot stage at 150 °C for 5 min of thermal annealing treatment to form a black perovskite film.

[0073] Comparative Example 1

[0074] (1) Dissolve 2 g of lead iodide in 5 ml of N,N-dimethylformamide solution;

[0075] (2) After the lead iodide in step (1) is completely dissolved, add 3 ml of hydroiodic acid dropwise and stir to obtain a uniform pale yellow precipitate;

[0076] (3) Vacuum filter the pale yellow precipitate in step (2) and transfer it to a container for washing with anhydrous ether to remove excess hydroiodic acid and N,N-dimethylformamide solution;

[0077] (4) Transfer the washed pale yellow precipitate in step (3) to a container again and place it in a vacuum drying oven filled with argon at 60 °C for 12 hours to obtain an intermediate material;

[0078] At this time, the general formula of the intermediate material is: DMAPbI 3 ;

[0079] (9) Weigh 0.4 g of the intermediate material in step (4), and weigh 0.2 g of cesium iodide, and then dissolve the three raw materials in 1 ml of N,N-dimethylformamide solution to obtain a precursor solution;

[0080] At this time, the general formula of the precursor solution is: Cs 0.8 DMA 0.2 PbI 3 ;

[0081] (6) Coat the precursor solution in step (5) on the conductive glass deposited with titanium oxide, and then place the substrate in a spin coater. The spin coater rotates at a speed of 4000 revolutions per second for 30 s;

[0082] (7) Place the substrate in step (6) on a hot stage at 200 °C for 5 min of thermal annealing treatment to form a black perovskite film;

[0083] This perovskite film can be applied to solar cells, light-emitting diodes, photodiodes, lasers, thin-film transistors, photodetectors or microsensor devices.

[0084] Comparative Example 2

[0085] (1) Dissolve 1.8 g of lead iodide and 0.2 g of lead chloride in 5 ml of N,N-dimethylformamide solution;

[0086] (2) After the lead iodide in step (1) is completely dissolved, add 3 ml of hydroiodic acid dropwise and stir to obtain a uniform pale yellow precipitate;

[0087] (3) Vacuum filter the pale yellow precipitate in step (2) and transfer it to a container, then wash it with anhydrous ether to remove the excess hydroiodic acid and N,N-dimethylformamide solution;

[0088] (4) Transfer the washed pale yellow precipitate in step (3) to a container again and place it in a vacuum drying oven filled with argon at 60 °C for drying for 12 hours to obtain an intermediate material;

[0089] At this time, the general formula of the intermediate material is: DMAPbI 2.3 Cl 0.7 ;

[0090] (10) Weigh 0.4 g of the intermediate material in step (4), and weigh 0.2 g of cesium iodide, then dissolve the three raw materials in 1 ml of N,N-dimethylformamide solution to obtain a precursor solution;

[0091] At this time, the general formula of the precursor solution is: Cs 0.8 DMA 0.2 PbI 2.3 Cl 0.7 ;

[0092] (6) Coat the precursor solution in step (5) on the conductive glass deposited with titanium oxide, then place the substrate in a spin coater, and the spin coater rotates at a speed of 4000 revolutions per second for 30 s;

[0093] (7) Place the substrate in step (6) on a hot plate at 200 °C for a thermal annealing treatment for 5 min to form a black perovskite film;

[0094] This perovskite film can be applied to solar cells, light-emitting diodes, photodiodes, lasers, thin-film transistors, photodetectors or microsensor devices.

[0095] Comparative Example 3

[0096] (1) Dissolve 1.6 g of lead iodide, 0.2 g of lead chloride, and 0.2 g of lead bromide in 5 ml of N,N-dimethylformamide solution;

[0097] (2) After the lead iodide in step (1) is completely dissolved, add 3 ml of hydroiodic acid dropwise and stir to obtain a uniform pale yellow precipitate;

[0098] (3) Vacuum filter the pale yellow precipitate in step (2) and transfer it to a container, then wash it with anhydrous ether to remove the excess hydroiodic acid and N,N-dimethylformamide solution;

[0099] (4) Transfer the washed pale yellow precipitate in step (3) to a container again and dry it in a vacuum drying oven filled with argon at 60 °C for 12 hours to obtain the intermediate material;

[0100] At this time, the general formula of the intermediate material is: DMAPbI 0.8 Br 1.5 Cl 0.7 ;

[0101] (11) Weigh 0.4 g of the intermediate material in step (4), and weigh 0.2 g of cesium iodide, and then dissolve the three raw materials in 1 ml of N,N-dimethylformamide solution to obtain the precursor solution;

[0102] At this time, the chemical formula of the precursor solution is: Cs 0.8 DMA 0.2 PbI 0.8 Br 1.5 Cl 0.7 ;

[0103] (6) Coat the precursor solution in step (5) on the conductive glass deposited with titanium oxide, and then place the substrate in a spin coater. The spin coater rotates at a speed of 4000 revolutions per second for 30 s;

[0104] (7) Place the substrate in step (6) on a hot stage at 200 °C for 5 min of thermal annealing treatment to form a black perovskite film;

[0105] The perovskite films prepared in the above Examples 1, 2, 3, and 4 can be applied to solar cells, light-emitting diodes, photodiodes, lasers, thin-film transistors, photodetectors, or microsensor devices, and the photoelectric conversion efficiency of all exceeds 10%. The light conversion rates in Comparative Examples 1 and 2 are both greater than 10% but the stability is poor. The light conversion rate in Comparative Example 3 is 6%, and the stability is also very poor.

[0106] In the present invention, bismuth element is introduced at the B site of the perovskite crystal structure, and at the same time, an inorganic halide salt containing bismuth is used as one of the raw materials to prepare an intermediate material with a general formula of DMABiI z1 Br z2 Cl 3-z1-z2 Then, using this intermediate material as one of the raw materials, other raw material salts such as inorganic halides containing lead are added to prepare a perovskite with a general formula of Cs x DMA 1-x Bi y Pb 1- y I z1 Br z2 Cl 3-z1-z2, a precursor solution where (x≠0, x≠1; y≠0, y≠1; z1≠0, z2≠0). Finally, the precursor solution is deposited on the conductive glass with titanium oxide attached by means of a spin coater, and heat annealing treatment is carried out at a temperature of 80 - 150 °C to finally obtain a perovskite film with a photoelectric conversion efficiency exceeding 8% and good stability. Both the A-site and B-site in the perovskite crystal structure are occupied by two kinds of ions, which improves the tolerance factor of the crystal, thereby making the perovskite film have good stability, and at the same time, the photoelectric conversion efficiency can also exceed 8%.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing a perovskite film, characterized in that, it comprises the following steps: (1) Dissolve an inorganic bismuth halide in an N,N-dimethylformamide solution; (2) After the inorganic bismuth halide in step (1) is completely dissolved, add hydroiodic acid dropwise and stir to obtain a pale yellow precipitate; (3) Vacuum filter the pale yellow precipitate in step (2) and transfer it to a container for washing with anhydrous ether; (4) Transfer the washed pale yellow precipitate in step (3) to a container again and place it in a vacuum drying oven at 60 °C for drying for 12 hours to obtain an intermediate material; (5) Weigh the intermediate material in step (4), and weigh an inorganic lead halide and cesium iodide, and then dissolve all the raw materials in an N,N-dimethylformamide solution to obtain a precursor solution; (6) Deposit the precursor solution in step (5) on a substrate; (7) Perform thermal annealing treatment on the substrate in step (6) to form a black perovskite film; wherein, the inorganic bismuth halide is one or more mixtures of bismuth iodide, bismuth chloride, and bismuth bromide; the inorganic lead halide is lead iodide or one or more mixtures of lead iodide, lead chloride, and lead bromide, and one of the mixtures is lead iodide; The general formula of the intermediate material is: DMABiI z1 Br z2 Cl 3-z1-z2 ; The general formula of the precursor solution is: Cs x DMA 1-x Bi y Pb 1-y I z1 Br z2 Cl 3-z1-z2 , where x≠0, x≠1; y≠0, y≠1; z1≠0, z2≠0.

2. The method for preparing a perovskite film according to claim 1, characterized in that, the inorganic bismuth halide is bismuth bromide, and the inorganic lead halide is lead iodide.

3. The method for preparing a perovskite film according to claim 1, characterized in that, the thermal annealing treatment temperature in step (7) is 80 °C to 150 °C, and the annealing time is 5 min.

4. The method for preparing a perovskite film according to claim 1, characterized in that, the mass ratio of the intermediate material, inorganic lead halide, and cesium iodide in step (5) is (1.5 - 2.5):(2 - 2.5):(0.5 - 1).

5. The method for preparing a perovskite film according to claim 1, characterized in that, the mass of lead iodide in the mixture of inorganic lead halides in step (1) is 80% - 90% of the total mass of the mixture.

6. The method for preparing a perovskite film according to claim 1, characterized in that, in step (6), a spin coater is used to deposit the precursor solution on the substrate, and the rotation speed of the spin coater is 4000 revolutions per second, and the rotation time is 30 s.

7. The method for preparing a perovskite film according to claim 1, characterized in that, the substrate is a conductive glass deposited with titanium oxide.

8. The method for preparing a perovskite film according to claim 1, characterized in that, the vacuum drying gas in step (4) is one or more mixtures of argon, nitrogen, and oxygen.

9. Apply the perovskite film prepared by using the method for preparing a perovskite film according to any one of claims 1 - 8 to the preparation of solar cells, light-emitting diodes, photodiodes, lasers, thin-film transistors, photodetectors, or microsensor devices.

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