Perovskite solar cell based on controlling perovskite thin film crystallization and preparation method thereof

Abstract

This invention discloses a perovskite solar cell based on controlled perovskite thin film crystallization and its fabrication method. A hole transport layer is spin-coated onto conductive glass. A perovskite precursor solution is prepared by custom-synthesizing small organic molecules with different functional groups using Michael addition reaction as perovskite precursor additives. A perovskite thin film is then prepared on indium tin oxide transparent conductive glass with deposited hole transport material using an anti-solvent method. After annealing, the film surface is smooth and dense, with large grain size, low defect state density, and crystal orientation perpendicular to the substrate. A passivation layer precursor solution is then spin-coated to form a passivation layer. An electron transport layer material is then vacuum-deposited onto the passivation layer. Finally, a barrier layer material and a metal electrode are sequentially thermally deposited onto the electron transport layer material to obtain the perovskite solar cell. The prepared inverted perovskite solar cell exhibits excellent photoelectric conversion efficiency and outstanding device stability.

Description

Technical Field

[0001] This invention belongs to the field of optoelectronic materials and devices technology, and specifically relates to a method for synthesizing organic multifunctional molecules to control perovskite crystallization kinetics for use in high-efficiency and stable solar cells. Background Technology

[0002] Perovskite solar cells, characterized by low cost, tunable bandgap, and high theoretical limit photoelectric conversion efficiency, are currently one of the hottest research topics. Inverted-structure perovskite solar cells have seen rapid development in photoelectric conversion efficiency, reaching a record-breaking certified value of 26.14%, thanks to the development of novel hole transport materials and the use of control strategies such as additive engineering and interface engineering, demonstrating their strong commercial investment and application potential. The preparation of high-quality perovskite thin films is crucial for obtaining devices with excellent photoelectric performance and stability. However, during the preparation of perovskite thin films, surface and grain boundary defects that dominate non-radiative recombination are easily formed. Therefore, controlling the growth and crystallization process of perovskite thin films to reduce perovskite surface or grain boundary defects is an effective strategy to improve the performance of perovskite solar cells.

[0003] Currently, various types of materials (inorganic salts, organic halide salts, small organic molecules, and polymers) have been used as precursor additives to regulate the crystallization and growth process of perovskite thin films, inhibit the formation of defects, or reduce defect density. Organic halide salts and inorganic salts are widely studied due to their effective passivation properties. It has been reported that long-chain alkyl ammonium halides readily convert the top three-dimensional perovskite layer into a two-dimensional perovskite layer, hindering interfacial carrier transport. Small-radius halide anions readily bind to the perovskite lattice, leading to octahedral distortion. Therefore, the use of organic halide salts and inorganic salts as precursor additives carries certain risks. Small organic molecules, with their more flexible structures and designable functional groups, can avoid these effects and may be more effective in passivating perovskite film defects. Theory and practice have shown that specific functional groups such as hydroxyl, carboxyl, and amino groups can regulate the growth, crystallization, and surface defect passivation of perovskite thin films to varying degrees. Therefore, developing novel organic small molecule precursor additives with multiple functional groups and optimal spatial structures is crucial for obtaining high-quality perovskite thin films and high-performance perovskite solar cell devices.

[0004] Additive engineering plays a crucial role in achieving high-performance and stable high-quality light-absorbing layers for perovskite solar cells. Various functional groups in additives exert different regulatory effects on the perovskite layer. However, few additive molecules can synergistically achieve the dual functions of regulating crystallization and passivating defects. Summary of the Invention

[0005] To address the aforementioned deficiencies in the existing technology, the present invention aims to provide a perovskite solar cell with controlled perovskite thin film crystallization and its preparation method. This method utilizes Michael addition reaction to synthesize 2-ureido-4-pyrimidinone (UPy) organic small molecules with different functional groups as perovskite precursor additives to prepare perovskite precursor solutions, thereby obtaining perovskite thin films with smooth and dense surfaces, large grain sizes, low defect state density, and crystal orientation perpendicular to the substrate, thus preparing high photoelectric conversion efficiency and stable inverse perovskite solar cells.

[0006] The present invention is achieved through the following technical solution.

[0007] One aspect of the present invention provides a method for fabricating a perovskite solar cell based on controlled perovskite thin film crystallization, comprising the following steps:

[0008] (1) Clean the indium tin oxide transparent conductive glass substrate and treat it with ultraviolet ozone.

[0009] (2) Dissolve the hole transport layer material in an ethanol solution to prepare a hole transport layer precursor solution;

[0010] (3) Cesium iodide, methylamine hydroiodate, formamidinium hydroiodate, lead iodide and methylamine lead trichloromonocyanate single crystals were dissolved in an organic solvent in a molar ratio of (0.03~0.05):(0.03~0.05):(0.70~0.90):(0.95~1.05):(0.04~0.06) to obtain a mixed solution. Additives were added at a mass ratio of 1~5mg per 1mL of the mixed solution to prepare a perovskite precursor solution.

[0011] (4) Dissolve the passivation layer material in isopropanol solution to prepare a passivation layer precursor solution;

[0012] (5) A hole transport layer precursor liquid is spin-coated onto a cleaned and treated transparent conductive glass, and then annealed to obtain a hole transport layer.

[0013] (6) A perovskite thin film is obtained by spin-coating a perovskite precursor solution onto a transparent conductive glass with a hole transport layer using an anti-solvent method and then annealing.

[0014] (7) A passivation layer precursor solution is spin-coated onto a transparent conductive glass on which a perovskite thin film has been deposited to form a passivation layer;

[0015] (8) Electron transport layer material is vacuum thermally deposited onto the passivation layer;

[0016] (9) A barrier layer material and a metal electrode are sequentially thermally deposited on the electron transport layer material to obtain a perovskite solar cell.

[0017] Preferably, the hole transport layer material is one of (2-(4-(bis(4-methoxyphenyl)amino)phenyl)-1-cyanovinyl)phosphonic acid, ethyl 2-[(2-chlorophenyl)(phenyl)amino]benzoate, or (4-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid.

[0018] Preferably, the additive is prepared according to the following method:

[0019] Guanidine carbonate and 2-acetylbutyrolactone were mixed with anhydrous ethanol at a mass ratio of (5-15):(2-10):(40-80). The mixture was then refluxed overnight in (10-20) parts of triethylamine. The pH was adjusted to neutral, and the mixture was filtered to obtain a white solid powder. The powder was washed and dried to obtain the additive.

[0020] Preferably, the hole transport layer precursor liquid is spin-coated onto a glass / indium tin oxide substrate at a speed of 3000-6000 rpm for 30-60 seconds, and then annealed on a hot plate at 90-120°C for 10-20 minutes.

[0021] Preferably, the perovskite precursor solution is spin-coated using an anti-solvent method, with a concentration of 1.3–1.8 mol / L. -1 The perovskite precursor solution was spin-coated at 4000–6000 rpm for 40–80 s, and 110–200 μL of organic solvent was added dropwise in the last 7–10 seconds. The perovskite film was then annealed at 60–120 °C for 5–20 minutes to obtain the perovskite film.

[0022] Preferably, the organic solvent is chlorobenzene, ethyl acetate, or anisole.

[0023] Preferably, the passivation layer material is one of 2-phenylethylamine hydrochloride, phenylethylamine iodide, phenylethylamine iodide, or ethylenediamine hydroiodide.

[0024] As a preferred option, the passivation layer is spin-coated and annealed at 80–120°C for 3–15 min.

[0025] As a preferred option, the electron transport layer material is C 60 The thickness is 15-30 nm;

[0026] The barrier layer material is copper bath resin, and the thickness of the hot-dip evaporation coating is 3-8 nm;

[0027] The metal electrode is one of silver, gold or copper, and the thickness of the metal electrode is 80-120 nm.

[0028] In another aspect, the present invention provides a perovskite solar cell based on controlled crystallization of a perovskite thin film prepared by the above method.

[0029] The present invention, by adopting the above technical solution, has the following beneficial effects:

[0030] (1) High-quality perovskite thin film: In this invention, an appropriate amount of additive molecules are added to the perovskite precursor solution, and the -OH groups in the additive fix the uncoordinated Pb 2+ Significant effects were observed in ionization, passivation of lead iodine antisite defects, mitigation of magnetic hysteresis, and reduction of nonradiative recombination. Furthermore, the C=O and -NH2 groups interacted with formamidinium cations via hydrogen bonds, thereby reducing residual strain and adjusting crystal orientation. Consequently, the obtained perovskite films exhibited fewer surface defects, larger average grain size, and higher flatness.

[0031] (2) High stability: The high water and oxygen barrier capacity of the high-quality perovskite thin film obtained by optimizing and controlling crystallization results in higher stability of the perovskite solar cell device.

[0032] (3) Reduced current hysteresis: Thanks to the optimized additive scheme, the perovskite thin film with low defect density and high carrier concentration has reduced the current hysteresis of the prepared perovskite solar cell.

[0033] (4) High JV performance: By using an additive strategy to passivate defects and control crystallization of perovskite thin films, the perovskite solar cell devices fabricated exhibit higher open-circuit voltage (1.20V), fill factor (84%) and photoelectric conversion efficiency (25.75%). Attached Figure Description

[0034] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, do not constitute an undue limitation of the invention. In the drawings:

[0035] Figure 1 These are SEM images of the perovskite film prepared in a nitrogen atmosphere according to the present invention and the perovskite film prepared by conventional methods.

[0036] Figure 2 This is a grazing incidence wide-angle X-ray scattering pattern of the perovskite film prepared in a nitrogen atmosphere according to the present invention and the perovskite film prepared by conventional methods.

[0037] Figure 3 This is a structural diagram of the perovskite solar cell device prepared in a nitrogen atmosphere according to the present invention;

[0038] Figure 4 This is a JV curve diagram of the perovskite solar cell prepared in a nitrogen atmosphere according to the present invention and the perovskite solar cell prepared by conventional methods.

[0039] Figure 5The graphs show the changes in photoelectric conversion efficiency over time of the perovskite solar cells prepared in nitrogen atmosphere according to the present invention and those prepared in a conventional manner.

[0040] Figure 6 This is a dark current curve of the perovskite solar cell prepared in a nitrogen atmosphere according to the present invention and the perovskite solar cell prepared in a conventional manner. Detailed Implementation

[0041] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The illustrative embodiments and descriptions of the present invention are used to explain the present invention, but are not intended to limit the present invention.

[0042] The present invention provides a method for controlling perovskite crystallization kinetics to prepare high-efficiency and stable solar cells, comprising the following steps:

[0043] Step 1: Clean the glass / indium tin oxide substrate sequentially with soapy water, deionized water, and ethanol, and sonicate it for 20 minutes in each solution. Then, treat the cleaned substrate with ultraviolet ozone for 15 minutes before use.

[0044] Step 2: Dissolve the hole transport layer material in an ethanol solution to prepare a 1.0 mg / mL solution. -1 Concentration of hole transport layer precursor solution.

[0045] The hole transport layer material is (2-(4-(bis(4-methoxyphenyl)amino)phenyl)-1-cyanovinyl)phosphonic acid, ethyl 2-[(2-chlorophenyl)(phenyl)amino]benzoate, or (4-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid.

[0046] Step 3: Cesium iodide, methylamine hydroiodate, formamidinium hydroiodate, lead iodide, and methylamine lead trichloroisocyanuric acid single crystals are dissolved in an organic solvent in a molar ratio of (0.03-0.05):(0.03-0.05):(0.70-0.90):(0.95-1.05):(0.04-0.06) to obtain a mixed solution. Additives are added at a mass ratio of 1-5 mg per 1 mL of the mixed solution to prepare a perovskite precursor solution.

[0047] The additive was prepared as follows: guanidine carbonate and 2-acetylbutyrolactone were mixed and stirred in anhydrous ethanol at a mass ratio of (5–15):(2–10):(40–80). The mixture was then placed in (10–20) parts of triethylamine and refluxed overnight at 40–60°C. The suspension turned yellow and turbid. After cooling, the pH was adjusted to 6–7 using hydrochloric acid solution. The mixture was filtered to obtain a white solid powder, washed three times with ethanol, and dried to obtain the additive.

[0048] Step 4: Dissolve the passivation layer material 2-phenylethylamine hydrochloride, phenylethylamine iodide, phenylethylamine iodide or ethylenediamine hydroiodide in isopropanol solution to prepare a passivation layer precursor solution.

[0049] Step 5: Spin-coat the hole transport layer precursor liquid onto the cleaned and treated transparent conductive glass at a speed of 3000-6000 rpm onto the glass / indium tin oxide substrate for 30-60 seconds, and anneal on a hot plate at 90-120°C for 10-20 minutes to obtain the hole transport layer.

[0050] Step 6: On the transparent conductive glass with a hole transport layer, spin-coat a solution with a concentration of 1.3–1.8 mol / L using an anti-solvent method. -1 The perovskite precursor solution was spin-coated at 4000–6000 rpm for 40–80 s, and 110–200 μL of organic solvent chlorobenzene, ethyl acetate, or anisole was added dropwise in the last 7–10 seconds. The mixture was then annealed at 60–120 °C for 5–20 minutes to obtain a perovskite film. Figure 1 The images show SEM images of the perovskite film prepared in a nitrogen atmosphere according to the present invention and the perovskite film prepared by conventional methods. The images show that the perovskite film prepared by the present invention has a low defect state density and a smooth and dense surface.

[0051] Figure 2 The images show grazing incidence wide-angle X-ray scattering (XRS) patterns of the perovskite films prepared in a nitrogen atmosphere according to the present invention and those prepared conventionally. The images show that the films prepared according to the present invention have a stronger crystal orientation.

[0052] Step 7: Spin-coat the passivation layer precursor solution onto the transparent conductive glass on which the perovskite film is deposited, and anneal at 80-120°C for 3-15 minutes to obtain the passivation layer.

[0053] The passivation layer material is one of 2-phenylethylamine hydrochloride, phenylethylamine iodide, phenylethylamine iodide, or ethylenediamine hydroiodide.

[0054] Step 8: Vacuum thermally deposit an electron transport layer material C with a thickness of 15–30 nm onto the passivation layer. 60 .

[0055] Step 9: Sequentially thermally deposit a barrier layer material of 3-8 nm thickness, copper bath, and a metal electrode of 80-120 nm thickness onto the electron transport layer material to obtain a perovskite solar cell.

[0056] Figure 3 This is a structural diagram of the perovskite solar cell device prepared in a nitrogen atmosphere according to the present invention.

[0057] The present invention will be further illustrated below through different embodiments.

[0058] Example 1

[0059] Step 1) Clean the glass / indium tin oxide substrate sequentially with soapy water, deionized water and ethanol, sonicate in each solution for 20 minutes, and then treat the cleaned substrate with ultraviolet ozone for 15 minutes before use.

[0060] Step 2) Dissolve the hole transport layer material (2-(4-(bis(4-methoxyphenyl)amino)phenyl)-1-cyanovinyl)phosphonic acid in an ethanol solution to prepare a 0.5 mg / mL solution. -1 Concentration of hole transport layer precursor solution.

[0061] Step 3) Cesium iodide, methylamine hydroiodate, formamidinium hydroiodate, lead iodide and methylamine lead trichloromonocyanate single crystals were dissolved in the organic solvent chlorobenzene in a molar ratio of 0.03:0.05:0.70:1.05:0.05 to obtain a mixed solution. Additives were added at a mass ratio of 5 mg per 1 mL of the mixed solution to prepare a perovskite precursor solution.

[0062] The additive was prepared as follows: guanidine carbonate and 2-acetylbutyrolactone were mixed in anhydrous ethanol at a mass ratio of 10:7:80 and stirred. The mixture was then placed in 15 parts of triethylamine and refluxed overnight at 60°C. The suspension turned yellow and turbid. After cooling, the pH was adjusted to 6-7 using hydrochloric acid solution. A white solid powder was obtained by filtration, washed three times with ethanol, and dried to obtain the additive.

[0063] Step 4) Dissolve the passivation layer material 2-phenylethylamine hydrochloride in isopropanol solution to prepare a passivation layer precursor solution.

[0064] Step 5) Spin-coat the hole transport layer precursor liquid onto the cleaned and treated transparent conductive glass at a speed of 4000 rpm on the glass / indium tin oxide substrate for 50 seconds, and anneal on a hot plate at 110°C for 18 minutes to obtain the hole transport layer.

[0065] Step 6) On a transparent conductive glass with a hole transport layer, spin-coat a 1.5 mol / L solution using an anti-solvent method. -1 The perovskite precursor solution was spin-coated at 5000 rpm for 60 seconds, and 110 μL of organic solvent chlorobenzene was added dropwise in the last 10 seconds. The mixture was then annealed at 100 °C for 10 minutes to obtain a perovskite film.

[0066] Step 7) Spin-coat the passivation layer precursor solution onto the transparent conductive glass on which the perovskite film is deposited, and anneal at 80°C for 15 min to obtain the passivation layer.

[0067] Step 8) Vacuum thermally deposit an electron transport layer material C with a thickness of 20 nm onto the passivation layer. 60 .

[0068] Step 9) A 5nm thick barrier layer material, copper bath, and a 100nm thick metal electrode, gold are sequentially thermally vapor-deposited onto the electron transport layer material to obtain a perovskite solar cell.

[0069] Under standard test conditions (AM1.5G illumination), the solar cell device fabricated in this example exhibits a photoelectric conversion efficiency of 25.75%, an open-circuit voltage of 1.20V, and a short-circuit current of 25.53mA / cm². 2 The fill factor is 84.04%.

[0070] Example 2

[0071] Step 1) Clean the glass / indium tin oxide substrate sequentially with soapy water, deionized water and ethanol, sonicate in each solution for 20 minutes, and then treat the cleaned substrate with ultraviolet ozone for 15 minutes before use.

[0072] Step 2) Dissolve ethyl 2-[(2-chlorophenyl)(phenyl)amino]benzoate, the hole transport layer material, in an ethanol solution to prepare a solution of 0.8 mg / mL. -1 Concentration of hole transport layer precursor solution.

[0073] Step 3) Cesium iodide, methylamine hydroiodate, formamidinium hydroiodate, lead iodide and methylamine lead trichloromonocyanate single crystals were dissolved in ethyl acetate in an organic solvent at a molar ratio of 0.05:0.04:0.80:0.95:0.06 to obtain a mixed solution. Additives were added at a mass ratio of 1 mg per 1 mL of the mixed solution to prepare a perovskite precursor solution.

[0074] The additive was prepared as follows: guanidine carbonate and 2-acetylbutyrolactone were mixed in anhydrous ethanol at a mass ratio of 15:2:60 and stirred. The mixture was then placed in 20 parts of triethylamine and refluxed overnight at 50°C. The suspension turned yellow and turbid. After cooling, the pH was adjusted to 6-7 using hydrochloric acid solution. A white solid powder was obtained by filtration, washed three times with ethanol, and dried to obtain the additive.

[0075] Step 4) Dissolve the passivation layer material phenylethyl iodide in isopropanol solution to prepare a passivation layer precursor solution.

[0076] Step 5) Spin-coat the hole transport layer precursor liquid onto the cleaned and treated transparent conductive glass at a speed of 3000 rpm on the glass / indium tin oxide substrate for 60 seconds, and anneal on a hot plate at 120°C for 10 minutes to obtain the hole transport layer.

[0077] Step 6) On a transparent conductive glass with a hole transport layer, spin-coat a 1.6 mol / L solution using an anti-solvent method. -1The perovskite precursor solution was spin-coated at 6000 rpm for 40 seconds, and 150 μL of ethyl acetate organic solvent was added dropwise in the last 8 seconds. The mixture was then annealed at 120 °C for 5 minutes to obtain a perovskite film.

[0078] Step 7) Spin-coat the passivation layer precursor solution onto the transparent conductive glass on which the perovskite film is deposited, and anneal at 100°C for 8 min to obtain the passivation layer.

[0079] Step 8) Vacuum thermally deposit an electron transport layer material C with a thickness of 15 nm onto the passivation layer. 60 .

[0080] Step 9) A barrier layer material with a thickness of 8 nm, copper bath, and a metal electrode silver with a thickness of 90 nm are sequentially thermally vapor-deposited onto the electron transport layer material to obtain a perovskite solar cell.

[0081] Under standard test conditions (AM1.5G illumination), the solar cell device fabricated in this example exhibits a photoelectric conversion efficiency of 25.18%, an open-circuit voltage of 1.19V, and a short-circuit current of 25.50mA / cm². 2 The fill factor is 83.63%.

[0082] Example 3

[0083] Step 1) Clean the glass / indium tin oxide substrate sequentially with soapy water, deionized water and ethanol, sonicate in each solution for 20 minutes, and then treat the cleaned substrate with ultraviolet ozone for 15 minutes before use.

[0084] Step 2) Dissolve the hole transport layer material (4-(3,6-dimethyl-9H-carbazole-9-yl)butylphosphonic acid) in an ethanol solution to prepare a 1.0 mg / mL solution. -1 Concentration of hole transport layer precursor solution.

[0085] Step 3) Cesium iodide, methylamine hydroiodate, formamidinium hydroiodate, lead iodide and methylamine lead trichloroisocyanuric acid single crystals were dissolved in anisole in a molar ratio of 0.04:0.03:0.90:0.10:0.04 to obtain a mixed solution. Additives were added at a mass ratio of 3 mg per 1 mL of the mixed solution to prepare a perovskite precursor solution.

[0086] The additive was prepared as follows: guanidine carbonate and 2-acetylbutyrolactone were mixed and stirred in anhydrous ethanol at a mass ratio of 5:10:40. The mixture was then placed in 10 parts of triethylamine and refluxed overnight at 40°C. The suspension turned yellow and turbid. After cooling, the pH was adjusted to 6-7 using hydrochloric acid solution. A white solid powder was obtained by filtration, washed three times with ethanol, and dried to obtain the additive.

[0087] Step 4) Dissolve the passivation layer material phenylethyl iodide in isopropanol solution to prepare a passivation layer precursor solution.

[0088] Step 5) Spin-coat the hole transport layer precursor liquid onto the cleaned and treated transparent conductive glass at a speed of 5000 rpm on the glass / indium tin oxide substrate for 40 seconds, and anneal on a hot plate at 90°C for 20 minutes to obtain the hole transport layer.

[0089] Step 6) On a transparent conductive glass with a hole transport layer, spin-coat a 1.3 mol / L solution using an anti-solvent method. -1 The perovskite precursor solution was spin-coated at 4500 rpm for 70 seconds, and 200 μL of anisole, an organic solvent, was added dropwise in the last 7 seconds. The mixture was then annealed at 80 °C for 12 minutes to obtain a perovskite film.

[0090] Step 7) Spin-coat the passivation layer precursor solution onto the transparent conductive glass on which the perovskite film is deposited, and anneal at 110°C for 5 min to obtain the passivation layer.

[0091] Step 8) Vacuum thermally deposit an electron transport layer material C with a thickness of 25 nm onto the passivation layer. 60 .

[0092] Step 9) A 3nm thick barrier layer material, copper bath, and an 80nm thick metal electrode are sequentially thermally deposited on the electron transport layer material to obtain a perovskite solar cell.

[0093] Under standard test conditions (AM1.5G illumination), the solar cell device fabricated in this example exhibits a photoelectric conversion efficiency of 25.42%, an open-circuit voltage of 1.20V, and a short-circuit current of 25.46mA / cm². 2 The fill factor is 83.37%.

[0094] Example 4

[0095] Step 1) Clean the glass / indium tin oxide substrate sequentially with soapy water, deionized water and ethanol, sonicate in each solution for 20 minutes, and then treat the cleaned substrate with ultraviolet ozone for 15 minutes before use.

[0096] Step 2) Dissolve ethyl 2-[(2-chlorophenyl)(phenyl)amino]benzoate, the hole transport layer material, in an ethanol solution to prepare a solution of 1.0 mg / mL. -1 Concentration of hole transport layer precursor solution.

[0097] Step 3) Cesium iodide, methylamine hydroiodate, formamidinium hydroiodate, lead iodide, and methylamine lead trichloroisocyanurate single crystals were dissolved in the organic solvent chlorobenzene in a molar ratio of 0.035:0.05:0.85:1.05:0.05 to obtain a mixed solution. Additives were added at a mass ratio of 2 mg per 1 mL of the mixed solution to prepare a perovskite precursor solution.

[0098] The additive was prepared as follows: guanidine carbonate and 2-acetylbutyrolactone were mixed in anhydrous ethanol at a mass ratio of 8:7:50 and stirred. The mixture was then refluxed overnight at 45°C in 18 parts of triethylamine. The suspension turned yellow and turbid. After cooling, the pH was adjusted to 6-7 using hydrochloric acid solution. A white solid powder was obtained by filtration, washed three times with ethanol, and dried to obtain the additive.

[0099] Step 4) Dissolve the passivation layer material ethylenediamine hydroiodate in isopropanol solution to prepare a passivation layer precursor solution.

[0100] Step 5) Spin-coat the hole transport layer precursor liquid onto the cleaned and treated transparent conductive glass at a speed of 6000 rpm on the glass / indium tin oxide substrate for 30 seconds, and anneal on a hot plate at 100°C for 15 minutes to obtain the hole transport layer.

[0101] Step 6) On a transparent conductive glass with a hole transport layer, spin-coat a solution with a concentration of 1.8 mol / L using an anti-solvent method. -1 The perovskite precursor solution was spin-coated at 4000 rpm for 80 seconds, and 180 μL of organic solvent chlorobenzene was added dropwise in the last 9 seconds. The mixture was then annealed at 60 °C for 20 minutes to obtain a perovskite film.

[0102] Step 7) Spin-coat the passivation layer precursor solution onto the transparent conductive glass on which the perovskite film is deposited, and anneal at 120°C for 3 min to obtain the passivation layer.

[0103] Step 8) Vacuum thermally deposit an electron transport layer material C with a thickness of 30 nm onto the passivation layer. 60 .

[0104] Step 9) A 6 nm thick barrier layer material, copper bath, and a 120 nm thick copper metal electrode are sequentially thermally vapor-deposited onto the electron transport layer material to obtain a perovskite solar cell.

[0105] Under standard test conditions (AM1.5G illumination), the solar cell device fabricated in this example exhibits a photoelectric conversion efficiency of 25.62%, an open-circuit voltage of 1.20V, and a short-circuit current of 25.40mA / cm². 2 The fill factor is 83.05%.

[0106] Figure 4The JV curves of the perovskite solar cells prepared in a nitrogen atmosphere according to the present invention and those prepared in a conventional manner are shown. The perovskite solar cell devices prepared by the present invention have higher open-circuit voltage, fill factor and photoelectric conversion efficiency. Figure 5 The graphs show the photoelectric conversion efficiency of the perovskite solar cells prepared in nitrogen atmosphere according to the present invention and those prepared in a conventional manner, over time. The unencapsulated device prepared in the present invention has better storage stability. Figure 6 This is a dark current curve of the perovskite solar cell prepared in a nitrogen atmosphere according to the present invention and the perovskite solar cell prepared by conventional methods; the device prepared by the present invention has a lower dark current density.

[0107] As can be seen from the above embodiments, the perovskite solar cell prepared by the present invention has a photoelectric conversion efficiency of not less than 25.18%, an open-circuit voltage of 1.19V, and a short-circuit current of not more than 25.53mA / cm². 2 The fill factor is no less than 83.05%. By synthesizing small organic molecules with different functional groups as additives, the crystallinity and defects of the perovskite film are adjusted through Michael addition reactions, ultimately improving the quality of the perovskite film. Furthermore, the inverted perovskite solar cells prepared according to this strategy exhibit excellent photoelectric performance and stability.

[0108] This invention is not limited to the above embodiments. Based on the technical solutions disclosed in this invention, those skilled in the art can make some substitutions and modifications to some of the technical features without creative effort, and all such substitutions and modifications are within the protection scope of this invention.

Claims

1. A method for fabricating perovskite solar cells based on controlled perovskite thin film crystallization, characterized in that, Includes the following steps: (1) Clean the indium tin oxide transparent conductive glass substrate and treat it with ultraviolet ozone; (2) Dissolve the hole transport layer material in an ethanol solution to prepare a hole transport layer precursor solution; (3) Cesium iodide, methylamine hydroiodate, formamidinium hydroiodate, lead iodide and methylamine lead trichloromonocyanate single crystals were dissolved in an organic solvent in a molar ratio of (0.03~0.05):(0.03~0.05):(0.70~0.90):(0.95~1.05):(0.04~0.06) to obtain a mixed solution. 2-Ureido-4-pyrimidinone was added as an additive at a mass ratio of 1~5 mg per 1 mL of the mixed solution to prepare a perovskite precursor solution. (4) Dissolve the passivation layer material in isopropanol solution to prepare a passivation layer precursor solution; (5) A hole transport layer precursor liquid is spin-coated onto a cleaned and treated transparent conductive glass, and then annealed to obtain a hole transport layer. (6) A perovskite thin film is obtained by spin-coating a perovskite precursor solution onto a transparent conductive glass with a hole transport layer using an anti-solvent method and then annealing it. (7) A passivation layer precursor solution is spin-coated onto a transparent conductive glass on which a perovskite thin film has been deposited to form a passivation layer; (8) Vacuum thermal evaporation of electron transport layer material onto the passivation layer; (9) A barrier layer material and a metal electrode are sequentially thermally deposited on the electron transport layer material to obtain a perovskite solar cell; The hole transport layer material is one of (2-(4-(bis(4-methoxyphenyl)amino)phenyl)-1-cyanovinyl)phosphonic acid, ethyl 2-[(2-chlorophenyl)(phenyl)amino]benzoate, or (4-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid; The additive is prepared according to the following method: Guanidine carbonate and 2-acetylbutyrolactone were mixed with anhydrous ethanol at a mass ratio of (5~15):(2~10):(40~80). The mixture was refluxed overnight in (10~20) parts of triethylamine. The pH was adjusted to neutral. The mixture was filtered to obtain a white solid powder, washed, and dried to obtain the additive.

2. The method for preparing a perovskite solar cell based on controlled perovskite thin film crystallization according to claim 1, characterized in that, Spin-coat the hole transport layer precursor solution onto a glass / indium tin oxide substrate at a spin speed of 3000-6000 rpm for 30-60 seconds, and then anneal on a hot plate at 90-120 ℃ for 10-20 minutes.

3. The method for fabricating perovskite solar cells based on controlled perovskite thin film crystallization according to claim 1, characterized in that, The perovskite precursor solution was spin-coated using an anti-solvent method, with a concentration of 1.3–1.8 mol / L. -1 The perovskite precursor solution was spin-coated at 4000-6000 rpm for 40-80 seconds, and 110-200 µL of organic solvent was added dropwise in the last 7-10 seconds. The perovskite film was then annealed at 60-120 °C for 5-20 minutes to obtain the perovskite film.

4. The method for preparing a perovskite solar cell based on controlled perovskite thin film crystallization according to claim 3, characterized in that, The organic solvent is chlorobenzene, ethyl acetate, or anisole.

5. The method for fabricating a perovskite solar cell based on controlled perovskite thin film crystallization according to claim 1, characterized in that, The passivation layer material is one of 2-phenylethylamine hydrochloride, phenylethylamine iodide, phenylethylamine iodide, or ethylenediamine hydroiodide.

6. The method for fabricating a perovskite solar cell based on controlled perovskite thin film crystallization according to claim 1, characterized in that, Spin-coat the passivation layer and anneal at 80~120 ℃ for 3~15 min.

7. The method for fabricating a perovskite solar cell based on controlled perovskite thin film crystallization according to claim 1, characterized in that, The electron transport layer material is C 60 The thickness is 15~30nm; The barrier layer material is copper bath resin, and the thickness of the hot-dip evaporation is 3~8 nm; The metal electrode is one of silver, gold or copper, and the thickness of the metal electrode is 80~120 nm.

8. A perovskite solar cell based on controlled perovskite thin film crystallization prepared by the method described in any one of claims 1-7.

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