Small organic molecule doped perovskite solar cell containing carbonyl and nitrogen and preparation method thereof

Abstract

The invention discloses a carbonyl and nitrogen-containing small organic molecule doped perovskite solar cell and a preparation method thereof. The perovskite-doped solar cell sequentially comprises a cathode substrate, an electron transport layer, a carbonyl and nitrogen-containing small organic molecule-doped perovskite light absorption layer, a hole transport layer and an anode electrode from bottom to top, the small organic molecule containing the carbonyl group and the nitrogen is N, N-methylene dicarboxamide. The preparation method comprises the following steps: sequentially spin-coating the electron transport layer, the organic micromolecule perovskite light absorption layer containing carbonyl and nitrogen and the hole transport layer on the cathode substrate, and evaporating the anode electrode. The doped small organic molecules containing carbonyl and nitrogen can effectively passivate non-coordinated lead ions in the perovskite thin film, the crystallization of perovskite is improved, the residue of lead iodide is reduced, the service life of a carrier is prolonged, meanwhile, the carrier recombination phenomenon is reduced, and finally the photoelectric conversion efficiency of the perovskite-doped solar cell is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of perovskite solar cells, and in particular to a carbonyl- and nitrogen-containing organic small molecule doped perovskite solar cell and a preparation method thereof. Background Art

[0002] Perovskite solar cells have become a promising competitor for photovoltaic devices due to their excellent optoelectronic properties and low-cost solution processing. However, the nitrogen conditions required for most high-efficiency perovskite solar cells complicate the device manufacturing process, increase costs, and pose a huge challenge to the fabrication of perovskite films. Therefore, open-air manufacturing has become the trend for the commercialization of perovskite photovoltaics due to its low cost.

[0003] The two-step sequential solution deposition method is a common strategy for preparing perovskite films with excellent photovoltaic performance. In this method, lead iodide (PbI2) crystals pre-deposited on the substrate react with subsequently deposited organic amine salts to form a perovskite phase. However, the dense PbI2 film in this method hinders the intercalation reaction between PbI2 and organic cations to a certain extent, and also leads to a large amount of PbI2 remaining at the bottom of the perovskite film. Residual PbI2 is considered to be a double-edged sword in perovskite films. A small amount of PbI2 is beneficial to photovoltaic performance, but an excessive amount will lead to a decrease in photovoltaic performance and stability. Under light, PbI2 decomposes into metallic lead (Pb 0 ) and I2. Pb 0 It also acts as a recombination center for charge carriers, leading to increased non-radiative recombination and reduced stability. Therefore, removing residual PbI2 is necessary to reduce internal defects and thus produce high-quality perovskite films and high-performance perovskite solar cells, which has the potential to accelerate the commercialization of perovskite solar cells. Summary of the invention

[0004] In order to overcome the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a carbonyl- and nitrogen-containing organic small molecule doped perovskite solar cell and a preparation method thereof.

[0005] The invention prepares a doped perovskite solar cell with high photoelectric conversion efficiency and high stability by adding an organic small molecule containing carbonyl and nitrogen into a perovskite light-absorbing layer.

[0006] The purpose of the present invention is achieved by at least one of the following technical solutions.

[0007] The present invention provides a carbonyl- and nitrogen-containing organic small molecule doped perovskite solar cell, which comprises, from bottom to top, a cathode substrate, an electron transport layer, a carbonyl- and nitrogen-containing organic small molecule doped perovskite light absorption layer, a hole transport layer and an anode electrode.

[0008] The organic small molecules containing carbonyl and nitrogen doped perovskite light absorbing layer is formed by doping perovskite with organic small molecules containing carbonyl and nitrogen.

[0009] Furthermore, the organic small molecule containing carbonyl and nitrogen is N,N-methylenediformamide.

[0010] Furthermore, the organic small molecule doped perovskite light absorbing layer containing carbonyl and nitrogen is a perovskite material doped with an organic small molecule containing carbonyl and nitrogen, and the perovskite material is a material having ABX m Y 3-m A perovskite material with a structure, wherein A is at least one of CH3NH3 and C4H9NH3, B is at least one of Pb and Sn, X and Y are independently Cl, Br or I, and m is 1, 2 or 3; the mass ratio of the organic small molecule containing carbonyl and nitrogen to the B-position element is 0.3%-3.5%;

[0011] Further preferably, the perovskite material is FA 0.98 MA 0.02 PbI3.

[0012] Furthermore, the thickness of the carbonyl- and nitrogen-containing organic small molecule doped perovskite light-absorbing layer is 400-800 nm.

[0013] Furthermore, the cathode substrate is selected from indium tin oxide glass (ITO glass) or fluorine-doped tin oxide glass (FTO glass).

[0014] Furthermore, the electron transport layer is a TiO2 or SnO2 thin film; the thickness of the electron transport layer is 30 to 50 nm;

[0015] Further, the hole transport layer is at least one of NiO, CuO, CuSCN, CuI, tungsten trioxide, molybdenum trioxide, vanadium pentoxide, Spiro-OMeTAD, P3HT, PTAA, NPB, and TPD; the thickness of the hole transport layer is 30 to 100 nm;

[0016] Further preferably, the hole transport layer is Spiro-OMeTAD.

[0017] Furthermore, the anode electrode is Au with a thickness of

[0018] Further preferably, the anode electrode is gold with a thickness of

[0019] The method for preparing the above-mentioned carbonyl- and nitrogen-containing organic small molecule doped perovskite solar cell provided by the present invention comprises the following steps:

[0020] (1) cleaning a cathode substrate, and then performing a surface treatment on the cathode substrate to obtain a surface-treated cathode surface;

[0021] (2) sequentially spin coating an electron transport layer, a carbonyl- and nitrogen-containing organic small molecule doped perovskite light absorption layer, and a hole transport layer on the surface of the cathode after the surface treatment in step (1);

[0022] (3) vapor-depositing an anode electrode on the surface of the hole transport layer in step (2) to obtain the organic small molecule doped perovskite solar cell containing carbonyl and nitrogen.

[0023] Furthermore, in step (1), the cathode substrate treatment includes: first, ultrasonic cleaning with detergent, deionized water, acetone, anhydrous ethanol, and isopropanol for 15 to 20 minutes each; then drying in a vacuum drying oven at 70 to 90°C; and finally, subjecting the cleaned and dried cathode substrate surface to plasma surface treatment for 10 to 20 minutes.

[0024] Furthermore, the preparation of the electron transport layer in step (2) includes: spin coating the SnO2 aqueous solution on the surface of the surface-treated cathode substrate at 1000-5000 rpm for 30-50 seconds; then, annealing at 150-180°C for 30-90 minutes to form an electron transport layer on the surface of the cathode substrate.

[0025] Further preferably, the mass fraction of the SnO2 aqueous solution is 1% to 4%.

[0026] Furthermore, the preparation of the carbonyl- and nitrogen-containing organic small molecule doped perovskite light absorbing layer in step (2) comprises:

[0027] (a) dissolving an organic small molecule containing carbonyl and nitrogen and a metal halide in a solvent to generate a metal halide precursor solution, wherein the organic small molecule containing carbonyl and nitrogen is N,N-methylenediformamide; the metal halide comprises at least one of lead iodide, lead bromide, lead chloride, stannous iodide, stannous bromide and stannous chloride; and the solvent is a mixed solvent of dimethylformamide and dimethyl sulfoxide;

[0028] (b) spin coating the metal halide precursor solution on the surface of the electron transport layer at 1000-3000 rpm for 30-40 seconds; then, annealing at 50-100° C. for 30-120 seconds;

[0029] (c) dissolving an organic solute in a solvent, wherein the organic solute comprises at least one of methylamine iodide, methylamine bromide, methylamine chloride, methylamine iodide, methylamine bromide and methylamine chloride, and the solvent is isopropanol; then spin coating the solution on the film prepared in step (b) at 2000-5000 rpm for 30-40 seconds; subsequently, annealing at 150-180° C. for 10-60 minutes to obtain the organic small molecule doped perovskite light absorbing layer containing carbonyl and nitrogen.

[0030] Further preferably, in step (a), the concentration of organic small molecules containing carbonyl and nitrogen in the metal halide precursor solution is 1-10 mg / mL, and the concentration of metal halide is 1-1.6 mol / L; and the volume ratio of DMF and DMSO is 4:1-9:1.

[0031] Further preferably, the metal halide in step (a) is lead iodide.

[0032] Further preferably, in step (a), p-toluenesulfonic acid is also added to the metal halide precursor solution, and the concentration of p-toluenesulfonic acid is 0.5-3 mg / mL.

[0033] Furthermore, the preparation of the hole transport layer in step (2) includes: dissolving the hole transport layer material powder in chlorobenzene, adding 4-tert-butylpyridine and bis(trifluoromethylsulfonyl)imide lithium salt thereto, and stirring and mixing evenly (stirring overnight), and then spin coating at 4000-5000 rpm for 30-40s on the carbonyl- and nitrogen-containing organic small molecule doped perovskite light absorbing layer, and oxidizing it in an atmospheric environment for 8-24h to obtain the hole transport layer.

[0034] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0035] (1) The method for preparing a perovskite solar cell doped with an organic small molecule containing carbonyl and nitrogen provided by the present invention comprises adding an organic small molecule containing carbonyl and nitrogen to a perovskite precursor solution, adjusting the morphology and crystallization of the PbI2 film, and growing the PbI2 into a high-quality film with uniformly distributed pores. This provides more ion transfer pathways, provides sufficient space for the subsequent growth of the PVK film, and is conducive to the formation of a high-quality perovskite film. The addition of organic small molecules containing carbonyl and nitrogen effectively improves the crystallinity of the perovskite, passivates the uncoordinated lead ions in the perovskite film, reduces the residual lead iodide, prolongs the carrier lifetime, and reduces the carrier recombination phenomenon, and finally improves the photoelectric conversion efficiency of the doped perovskite solar cell; after adding p-toluenesulfonic acid, the photoelectric conversion efficiency of the doped perovskite solar cell is further improved.

[0036] (2) The present invention can be prepared in the air, is low-cost, environmentally friendly, and can be directly mass-produced, thus having a good application prospect.

[0037] (3) The organic small molecule doped perovskite solar cell containing carbonyl and nitrogen prepared by the present invention has high short-circuit current density, high open-circuit voltage, high fill factor and high photoelectric conversion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic structural diagram of a perovskite solar cell doped with organic small molecules containing carbonyl and nitrogen according to the present invention.

[0039] Figure 2 The present invention is a flow chart of the method for preparing a carbonyl- and nitrogen-containing organic small molecule doped perovskite solar cell device.

[0040] Figure 3 1 is a graph showing the relationship between current density and voltage of the solar cell devices in Example 1 and Comparative Example 1. DETAILED DESCRIPTION

[0041] The specific implementation of the present invention is further described below in conjunction with examples, but the implementation and protection of the present invention are not limited thereto. It should be noted that if there are processes that are not particularly described in detail below, they can be implemented or understood by those skilled in the art with reference to the prior art. If the manufacturer of the reagents or instruments used is not indicated, they are deemed to be conventional products that can be purchased commercially.

[0042] The embodiment of the present invention provides a carbonyl- and nitrogen-containing organic small molecule doped perovskite solar cell, such as Figure 1 It is shown to include a cathode substrate, an electron transport layer, a perovskite light-absorbing layer doped with organic small molecules containing carbonyl and nitrogen, a hole transport layer and an anode electrode.

[0043] The preparation process of the above-mentioned organic small molecules doped with carbonyl and nitrogen perovskite solar cells is as follows Figure 2 As shown, the following steps are included:

[0044] Step 1: The cathode substrate is ultrasonically cleaned with detergent, deionized water, acetone, anhydrous ethanol and isopropanol for 15-20 minutes respectively; thereafter, it is dried in a vacuum drying oven at 70-90°C.

[0045] Step 2: subjecting the cleaned and dried cathode substrate (ITO) to surface plasma treatment for 10-20 minutes. This treatment method utilizes the strong oxidizing property of ozone generated under microwaves to clean residual organic matter on the ITO surface, and at the same time can increase the oxygen vacancies on the ITO surface and improve the work function of the ITO surface.

[0046] Step 3: Spin-coat the SnO2 solution on the ITO surface treated in step 2 at 1000-5000 rpm for 30-50 seconds; then, anneal at 150-180° C. for 30-90 minutes to form an electron transport layer on the surface of the cathode substrate.

[0047] Step 4: Spin-coat a metal halide precursor solution on the surface of the electron transport layer; the metal halide precursor solution is doped with lead iodide and organic small molecules containing carbonyl and nitrogen. Spin-coat the precursor solution on the surface of the electron transport layer at 1000-3000 rpm for 30-40 seconds; then, anneal at 50-100°C for 30-120 seconds.

[0048] Step 5, dissolving the organic solute in a solvent, and spin coating the solution on the film prepared in step 4 at 2000-5000 rpm for 30-40 seconds; then, annealing at 150-180° C. for 10-60 minutes to obtain the organic small molecule doped perovskite light absorbing layer containing carbonyl and nitrogen.

[0049] Step 6: spin-coat a hole transport layer on the surface of the above-mentioned organic small molecule doped perovskite light-absorbing layer containing carbonyl and nitrogen.

[0050] Step 7: Vapor-deposit anode electrode gold (Au) on the surface of the hole transport layer with a thickness of 60-100 nm.

[0051] After the above steps are completed, an organic small molecule doped perovskite solar cell containing carbonyl and nitrogen is obtained.

[0052] The following is a further detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings.

[0053] Example 1

[0054] The structure of the perovskite solar cell device doped with organic small molecules containing carbonyl and nitrogen in Example 1 is: ITO / SnO2 / FA 0.98 MA 0.02 PbI3:C3H6N2O2 / Spiro-OMeTAD / Au.

[0055] The preparation process of the above-mentioned perovskite solar cell is as follows:

[0056] Step 1, the cathode substrate is ultrasonically cleaned with detergent, deionized water, acetone, anhydrous ethanol, and isopropanol for 20 minutes each; then dried in a drying oven at 80°C;

[0057] Step 2, subjecting the cleaned and dried cathode substrate (ITO) surface to a surface plasma treatment for 20 minutes, wherein the treatment method utilizes the strong oxidizing property of ozone generated under microwaves to clean residual organic matter on the ITO surface, and at the same time, can increase oxygen vacancies on the ITO surface and improve the work function of the ITO surface;

[0058] Step 3, spin coating the ITO surface treated in step 2 with a SnO2 aqueous solution (SnO2 mass fraction of 2.67%) at a speed of 4000 rpm for 30 seconds, and annealing at 150° C. for 60 minutes to form an electron transport layer;

[0059] Step 4: Spin-coating a perovskite active layer on the surface of the substrate treated as above:

[0060] (1) Preparation of metal halide precursor solution: Prepare a 1.5 mol / L PbI2 solution, wherein the solvent is a mixed solvent of DMF and DMSO (the volume ratio of DMF to DMSO is 9:1), stir at room temperature until completely dissolved, and then add 2 mg N,N-methylenediformamide and 0.5 mg p-toluenesulfonic acid to 1 mL of the solution.

[0061] (2) The metal halide precursor solution was spin-coated on the surface of the electron transport layer at 1500 rpm for 30 seconds; then, annealed at 70° C. for 60 seconds.

[0062] (3) dissolving an organic solute in a solvent, and spin coating the solution on the lead iodide film at 2000 rpm for 30 seconds; then, annealing at 150° C. for 10 minutes to obtain the organic small molecule doped perovskite light absorbing layer containing carbonyl and nitrogen. The solution is 90 mg FAI, 9 mg MACl and 6.39 mg MAI dissolved in 1 mL of isopropanol.

[0063] Step 5: Spin-coat the hole transport layer solution on the surface of the above-mentioned organic small molecule doped perovskite light-absorbing layer containing carbonyl and nitrogen at a speed of 4000 rpm for 30 seconds, and then oxidize overnight in an atmospheric environment. The hole transport layer solution is a mixed solution of 72.3 mg of Spiro-OMeTAD powder dissolved in 1 mL of chlorobenzene, to which 29 microliters of 4-tert-butylpyridine and 17.5 μL of bistrifluoromethylsulfonyl imide lithium salt (520 mg / mL in acetonitrile) are added.

[0064] Step 6: Vapor-deposit anode electrode gold on the surface of the hole transport layer to a thickness of 60 nm.

[0065] After the above steps are completed, an organic small molecule doped perovskite solar cell device containing carbonyl and nitrogen is obtained.

[0066] Comparative Example 1

[0067] The steps of Comparative Example 1 are basically the same as those of Example 1, with the only difference being that in Step 4, no organic small molecules containing carbonyl and nitrogen and p-toluenesulfonic acid are added for doping, and the remaining parameters are the same as those of Example 1. The comparative example obtains a perovskite solar cell that is not doped with organic small molecules containing carbonyl and nitrogen.

[0068] Figure 3 1 is a graph showing the relationship between current density and voltage of the perovskite solar cell doped with organic small molecules containing carbonyl and nitrogen in Example 1 and the undoped perovskite solar cell in Comparative Example 1; wherein the dotted line is the perovskite solar cell (structure: ITO / SnO2 / FA) not doped with organic small molecules containing carbonyl and nitrogen in Comparative Example 1 0.98 MA 0.02 The solid line is the current density and voltage curve of the organic solar cell doped with small organic molecules containing carbonyl and nitrogen in Example 1 (structure: ITO / SnO2 / FA 0.98 MA 0.02 PbI3:C3H6N2O2 / Spiro-OMeTAD / Au) current density and voltage curve; from Figure 3 It can be seen that the open circuit voltage (V oc ) is 1.05V, the short-circuit current density (J sc ) is 24.02 mA / cm 2 , the fill factor (FF) is 0.6956; the open circuit voltage (V oc ) is 1.13V, the short-circuit current density (J sc ) is 25.45mA / cm 2 , the filling factor (FF) is 0.7853. It can be seen that after doping with organic small molecules containing carbonyl and nitrogen, the short-circuit current density, open-circuit voltage and filling factor of perovskite solar cell devices have been significantly improved, indicating that the addition of organic small molecules containing carbonyl and nitrogen can effectively improve the carrier separation and transmission efficiency and reduce the internal defect state density of perovskite.

[0069] Comparative Example 2

[0070] The steps of Comparative Example 2 are basically the same as those of Example 1, with the only difference being that no organic small molecules containing carbonyl and nitrogen are added for doping in Step 4, and the remaining parameters are the same as those of Example 1. Comparative Example 2 produces a perovskite solar cell that is not doped with organic small molecules containing carbonyl and nitrogen.

[0071] Example 2

[0072] The structure of the perovskite solar cell device doped with organic small molecules containing carbonyl and nitrogen in Example 2: ITO / SnO2 / FA0.98 MA 0.02 PbI3:C3H6N2O2 / Spiro-OMeTAD / Au.

[0073] The preparation process of the above-mentioned perovskite solar cell is as follows:

[0074] Step 1, the cathode substrate is ultrasonically cleaned with detergent, deionized water, acetone, anhydrous ethanol, and isopropanol for 20 minutes each; then dried in a drying oven at 80°C;

[0075] Step 2, subjecting the cleaned and dried cathode substrate (ITO) surface to a surface plasma treatment for 20 minutes, wherein the treatment method utilizes the strong oxidizing property of ozone generated under microwaves to clean residual organic matter on the ITO surface, and at the same time, can increase oxygen vacancies on the ITO surface and improve the work function of the ITO surface;

[0076] Step 3, spin coating the ITO surface treated in step 2 with a SnO2 aqueous solution (SnO2 mass fraction of 2.67%) at a speed of 4000 rpm for 30 seconds, and annealing at 150° C. for 60 minutes to form an electron transport layer;

[0077] Step 4: Spin-coating a perovskite active layer on the surface of the substrate treated as above:

[0078] (1) Preparation of metal halide precursor solution: Prepare a 1.5 mol / L PbI2 solution, wherein the solvent is a mixed solvent of DMF and DMSO (the volume ratio of DMF to DMSO is 9:1), stir at room temperature until completely dissolved, and then add 1 mg N,N-methylenediformamide and 0.5 mg p-toluenesulfonic acid to 1 mL of the solution.

[0079] (2) The metal halide precursor solution was spin-coated on the surface of the electron transport layer at 1500 rpm for 30 seconds; then, annealed at 70° C. for 60 seconds.

[0080] (3) dissolving an organic solute in a solvent, and spin coating the solution on the lead iodide film at 2000 rpm for 30 seconds; then, annealing at 150° C. for 10 minutes to obtain the organic small molecule doped perovskite light absorbing layer containing carbonyl and nitrogen. The solution is 90 mg FAI, 9 mg MACl and 6.39 mg MAI dissolved in 1 mL of isopropanol.

[0081] Step 5: Spin-coat the hole transport layer solution on the surface of the above-mentioned perovskite-containing carbonyl and nitrogen-containing organic small molecule doped mineral light absorption layer at a speed of 4000 rpm for 30 seconds; then oxidize overnight in an atmospheric environment. The hole transport layer solution is a mixed solution of 72.3 mg of Spiro-OMeTAD powder dissolved in 1 mL of chlorobenzene, to which 29 microliters of 4-tert-butylpyridine and 17.5 μL of bistrifluoromethylsulfonyl imide lithium salt (520 mg / mL in acetonitrile) are added.

[0082] Step 6: Vapor-deposit anode electrode gold on the surface of the hole transport layer to a thickness of 60 nm.

[0083] After the above steps are completed, an organic small molecule doped perovskite solar cell device containing carbonyl and nitrogen is obtained.

[0084] Example 3

[0085] The structure of the perovskite solar cell device doped with organic small molecules containing carbonyl and nitrogen in Example 3: ITO / SnO2 / FA 0.98 MA 0.02 PbI3:C3H6N2O2 / Spiro-OMeTAD / Au.

[0086] The preparation process of the above-mentioned perovskite solar cell is as follows:

[0087] Step 1, the cathode substrate is ultrasonically cleaned with detergent, deionized water, acetone, anhydrous ethanol, and isopropanol for 20 minutes each; then dried in a drying oven at 80°C;

[0088] Step 2, subjecting the cleaned and dried cathode substrate (ITO) surface to a surface plasma treatment for 20 minutes, wherein the treatment method utilizes the strong oxidizing property of ozone generated under microwaves to clean residual organic matter on the ITO surface, and at the same time, can increase oxygen vacancies on the ITO surface and improve the work function of the ITO surface;

[0089] Step 3, spin coating the ITO surface treated in step 2 with a SnO2 aqueous solution (SnO2 mass fraction of 2.67%) at a speed of 4000 rpm for 30 seconds, and annealing at 150° C. for 60 minutes to form an electron transport layer;

[0090] Step 4: Spin-coating a perovskite active layer on the surface of the substrate treated as above:

[0091] (1) Preparation of metal halide precursor solution: Prepare a 1.5 mol / L PbI2 solution, wherein the solvent is a mixed solvent of DMF and DMSO (the volume ratio of DMF to DMSO is 9:1), stir at room temperature until completely dissolved, and then add 3 mg N,N-methylenediformamide and 0.5 mg p-toluenesulfonic acid to 1 mL of the solution.

[0092] (2) The metal halide precursor solution was spin-coated on the surface of the electron transport layer at 1500 rpm for 30 seconds; then, annealed at 70° C. for 60 seconds.

[0093] (3) dissolving an organic solute in a solvent, and spin coating the solution on the lead iodide film at 2000 rpm for 30 seconds; then, annealing at 150° C. for 10 minutes to obtain the organic small molecule doped perovskite light absorbing layer containing carbonyl and nitrogen. The solution is 90 mg FAI, 9 mg MACl and 6.39 mg MAI dissolved in 1 mL of isopropanol.

[0094] Step 5: Spin-coat the hole transport layer solution on the surface of the above-mentioned organic small molecule doped perovskite light-absorbing layer containing carbonyl and nitrogen at a speed of 4000 rpm for 30 seconds, and then oxidize overnight in an atmospheric environment. The hole transport layer solution is a mixed solution of 72.3 mg of Spiro-OMeTAD powder dissolved in 1 mL of chlorobenzene, to which 29 microliters of 4-tert-butylpyridine and 17.5 μL of bistrifluoromethylsulfonyl imide lithium salt (520 mg / mL in acetonitrile) are added.

[0095] Step 6: Vapor-deposit anode electrode gold on the surface of the hole transport layer to a thickness of 60 nm.

[0096] After the above steps are completed, an organic small molecule doped perovskite solar cell device containing carbonyl and nitrogen is obtained.

[0097] Example 4

[0098] The structure of the perovskite solar cell device doped with organic small molecules containing carbonyl and nitrogen in Example 4: ITO / SnO2 / FA 0.98 MA 0.02 PbI3:C3H6N2O2 / Spiro-OMeTAD / Au.

[0099] The preparation process of the above-mentioned perovskite solar cell is as follows:

[0100] Step 1, the cathode substrate is ultrasonically cleaned with detergent, deionized water, acetone, anhydrous ethanol, and isopropanol for 20 minutes each; then dried in a drying oven at 80°C;

[0101] Step 2, subjecting the cleaned and dried cathode substrate (ITO) surface to a surface plasma treatment for 20 minutes, wherein the treatment method utilizes the strong oxidizing property of ozone generated under microwaves to clean residual organic matter on the ITO surface, and at the same time, can increase oxygen vacancies on the ITO surface and improve the work function of the ITO surface;

[0102] Step 3, spin coating the ITO surface treated in step 2 with a SnO2 aqueous solution (SnO2 mass fraction of 2.67%) at a speed of 4000 rpm for 30 seconds, and annealing at 150° C. for 60 minutes to form an electron transport layer;

[0103] Step 4: Spin-coating a perovskite active layer on the surface of the substrate treated as above:

[0104] (1) Preparation of metal halide precursor solution: Prepare a 1.5 mol / L PbI2 solution, wherein the solvent is a mixed solvent of DMF and DMSO (the volume ratio of DMF to DMSO is 9:1), stir at room temperature until completely dissolved, and then add 5 mg N,N-methylenediformamide and 0.5 mg p-toluenesulfonic acid to 1 mL of the solution.

[0105] (2) The metal halide precursor solution was spin-coated on the surface of the electron transport layer at 1500 rpm for 30 seconds; then, annealed at 70° C. for 60 seconds.

[0106] (3) dissolving an organic solute in a solvent, and spin coating the solution on the lead iodide film at 2000 rpm for 30 seconds; then, annealing at 150° C. for 10 minutes to obtain the organic small molecule doped perovskite light absorbing layer containing carbonyl and nitrogen. The solution is 90 mg FAI, 9 mg MACl and 6.39 mg MAI dissolved in 1 mL of isopropanol.

[0107] Step 5: Spin-coat the hole transport layer solution on the surface of the above-mentioned organic small molecule doped perovskite light-absorbing layer containing carbonyl and nitrogen at a speed of 4000 rpm for 30 seconds, and then oxidize overnight in an atmospheric environment. The hole transport layer solution is a mixed solution of 72.3 mg of Spiro-OMeTAD powder dissolved in 1 mL of chlorobenzene, to which 29 microliters of 4-tert-butylpyridine and 17.5 μL of bistrifluoromethylsulfonyl imide lithium salt (520 mg / mL in acetonitrile) are added.

[0108] Step 6: Vapor-deposit anode electrode gold on the surface of the hole transport layer to a thickness of 60 nm.

[0109] After the above steps are completed, an organic small molecule doped perovskite solar cell device containing carbonyl and nitrogen is obtained.

[0110] Example 5

[0111] The steps of Example 5 are basically the same as those of Example 1, with the only difference being that p-toluenesulfonic acid is not added for doping in Step 4, and the remaining parameters are the same as those of Example 1. Example 5 produces a perovskite solar cell that is not doped with p-toluenesulfonic acid.

[0112] Table 1 compares various parameters of the perovskite solar cell devices prepared in Examples 1-5 and Comparative Examples 1-2.

[0113] Table 1 Comparison of parameters of Examples 1-5 and Comparative Examples 1-2

[0114]

[0115] It can be found from Table 1 that the short-circuit current density (J sc ) from 24.02mA / cm 2 Increased to 25.45mA / cm 2 , the fill factor (FF) increased from 0.6956 to 0.7853, and the open circuit voltage increased from 1.05V to 1.13V, which shows that the carrier separation and transmission efficiency of the perovskite solar cell doped with organic small molecules containing carbonyl and nitrogen are improved, and its internal defects are effectively suppressed. Its photoelectric conversion efficiency increased from 17.54% to 22.58%. At the same time, compared with the comparative example, the photoelectric conversion efficiency of the devices in Examples 2-5 has been improved to varying degrees.

[0116] The above-described embodiments only represent several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that for those skilled in the art, several changes, substitutions, and modifications may be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the attached claims.

Claims

1. A perovskite solar cell doped with an organic small molecule containing carbonyl and nitrogen, characterized in that: From bottom to top, it includes: a cathode substrate, an electron transport layer, a perovskite light-absorbing layer doped with organic small molecules containing carbonyl and nitrogen, a hole transport layer and an anode electrode.

2. The organic small molecule doped perovskite solar cell containing carbonyl and nitrogen according to claim 1, characterized in that: The organic small molecule containing carbonyl and nitrogen is N,N-methylenediformamide.

3. The organic small molecule doped perovskite solar cell containing carbonyl and nitrogen according to claim 1, characterized in that: The organic small molecule doped perovskite light absorbing layer containing carbonyl and nitrogen is a perovskite material doped with organic small molecules containing carbonyl and nitrogen. The perovskite material is a material having ABX m Y 3-m A perovskite material with a structure, wherein A is at least one of CH3NH3 and C4H9NH3, B is at least one of Pb and Sn, X and Y are independently Cl, Br or I, and m is 1, 2 or 3; the mass ratio of the organic small molecule containing carbonyl and nitrogen to the B-position element is 0.3%-3.5%; The thickness of the carbonyl- and nitrogen-containing organic small molecule doped perovskite light-absorbing layer is 400-800 nm.

4. The organic small molecule doped perovskite solar cell containing carbonyl and nitrogen according to claim 1, characterized in that: The cathode substrate is selected from indium tin oxide glass or fluorine-doped tin oxide glass; The electron transport layer is a TiO2 or SnO2 thin film; the thickness of the electron transport layer is 30 to 50 nm; The hole transport layer is at least one of NiO, CuO, CuSCN, CuI, tungsten trioxide, molybdenum trioxide, vanadium pentoxide, Spiro-OMeTAD, P3HT, PTAA, NPB, and TPD; the thickness of the hole transport layer is 30 to 100 nm; The anode electrode is Au and has a thickness of 5. The method for preparing a perovskite solar cell doped with an organic small molecule containing carbonyl and nitrogen according to any one of claims 1 to 4, characterized in that: The steps include: (1) cleaning a cathode substrate, and then performing a surface treatment on the cathode substrate to obtain a surface-treated cathode surface; (2) sequentially spin coating an electron transport layer, a carbonyl- and nitrogen-containing organic small molecule doped perovskite light absorption layer, and a hole transport layer on the surface of the cathode after the surface treatment in step (1); (3) vapor-depositing an anode electrode on the surface of the hole transport layer in step (2) to obtain the organic small molecule doped perovskite solar cell containing carbonyl and nitrogen.

6. The method for preparing a perovskite solar cell doped with an organic small molecule containing carbonyl and nitrogen according to claim 5, characterized in that: In step (1), the cathode substrate treatment includes: first, ultrasonic cleaning with detergent, deionized water, acetone, anhydrous ethanol, and isopropanol for 15 to 20 minutes each; then drying in a vacuum drying oven at 70 to 90° C.; finally, plasma surface treatment is performed on the cleaned and dried cathode substrate surface for 10 to 20 minutes.

7. The method for preparing a perovskite solar cell doped with an organic small molecule containing carbonyl and nitrogen according to claim 5, characterized in that: The preparation of the electron transport layer in step (2) includes: spin coating the SnO2 aqueous solution on the surface of the surface-treated cathode substrate at 1000-5000 rpm for 30-50 seconds; then, annealing at 150-180°C for 30-90 minutes to form an electron transport layer on the surface of the cathode substrate.

8. The method for preparing a perovskite solar cell doped with an organic small molecule containing carbonyl and nitrogen according to claim 5, characterized in that: The preparation of the carbonyl- and nitrogen-containing organic small molecule doped perovskite light absorbing layer in step (2) comprises: (a) dissolving an organic small molecule containing carbonyl and nitrogen and a metal halide in a solvent to generate a metal halide precursor solution, wherein the organic small molecule containing carbonyl and nitrogen is N,N-methylenediformamide; the metal halide comprises at least one of lead iodide, lead bromide, lead chloride, stannous iodide, stannous bromide and stannous chloride; and the solvent is a mixed solvent of dimethylformamide and dimethyl sulfoxide; (b) spin coating the metal halide precursor solution on the surface of the electron transport layer at 1000-3000 rpm for 30-40 seconds; then, annealing at 50-100° C. for 30-120 seconds; (c) dissolving an organic solute in a solvent, wherein the organic solute comprises at least one of methylamine iodide, methylamine bromide, methylamine chloride, methylamine iodide, methylamine bromide and methylamine chloride, and the solvent is isopropanol; then spin coating the solution on the film prepared in step (b) at 2000-5000 rpm for 30-40 seconds; subsequently, annealing at 150-180° C. for 10-60 minutes to obtain the organic small molecule doped perovskite light absorbing layer containing carbonyl and nitrogen.

9. The method for preparing a perovskite solar cell doped with an organic small molecule containing carbonyl and nitrogen according to claim 8, characterized in that: In step (a), the concentration of the organic small molecules containing carbonyl and nitrogen in the metal halide precursor solution is 1 to 10 mg / mL, and the concentration of the metal halide is 1 to 1.6 mol / L; In step (a), p-toluenesulfonic acid is also added to the metal halide precursor solution, and the concentration of p-toluenesulfonic acid is 0.5-3 mg / mL.

10. The method for preparing a perovskite solar cell doped with an organic small molecule containing carbonyl and nitrogen according to claim 5, characterized in that: The preparation of the hole transport layer in step (2) comprises: dissolving the hole transport layer material powder in chlorobenzene, adding 4-tert-butylpyridine and bis(trifluoromethylsulfonyl)imide lithium salt thereto, stirring and mixing evenly, and then spin coating at 4000-5000 rpm for 30-40s on the carbonyl- and nitrogen-containing organic small molecule doped perovskite light absorbing layer, and oxidizing it in an atmospheric environment for 8-24h to obtain the hole transport layer.

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