A chiral quasi-two-dimensional formamidinium-based perovskite solar cell and its preparation method and application

Abstract

The present invention discloses a chiral quasi-two-dimensional formamidinium-based perovskite solar cell, its preparation method, and application, belonging to the field of optoelectronic materials and device technology. It solves the technical problem that formamidinium-based two-dimensional perovskite films easily transform into a yellow non-perovskite phase, reducing the stability of the film and the efficiency of the device. The preparation method disclosed in the present invention utilizes an asymmetric chiral organic amine as a spacer cation in the quasi-two-dimensional perovskite solar cell to form a one-dimensional perovskite, stabilizes the α-phase formamidinium perovskite, and passivates the perovskite in situ, thereby achieving a high-efficiency and high-stability quasi-two-dimensional perovskite solar cell. This method taps into the enormous potential of chiral organic amine molecules in the perovskite field. The prepared chiral quasi-two-dimensional formamidinium-based perovskite solar cell has a light-to-electricity conversion efficiency greater than 20%, further improving efficiency while maintaining stability, and significantly advancing the commercialization of perovskite solar cells.

Description

Technical Field

[0001] The present invention belongs to the technical field of optoelectronic materials and devices, and particularly relates to a chiral quasi-two-dimensional formamidinium perovskite solar cell, its preparation method and application. Background Art

[0002] Metal halide perovskites have shown great application prospects due to their excellent photovoltaic performance and low manufacturing cost. The photoelectric conversion efficiency of organic-inorganic hybrid three-dimensional (3D) perovskite solar cells has exceeded 25%, which can be comparable to commercial crystalline silicon solar cells. However, the inherent instability of the materials and the sensitivity to environmental factors such as water, heat, oxygen, and ultraviolet light are still the main bottlenecks restricting their commercial applications. In contrast, quasi-two-dimensional (2D) perovskites with natural quantum well structures have received increasing attention due to their excellent environmental stability and crystallinity.

[0003] Quasi-2D perovskite materials can be regarded as cutting the three-dimensional perovskite along the <110> direction by introducing organic amine ions with larger ionic radii. The single-layer (two-dimensional n = 1) or multi-layer (quasi-two-dimensional 1 < n < ∞) inorganic parts are wrapped by organic amine ions with larger ionic radii, forming a structure similar to Ruddlesden–Popper. Its general structural formula is generally R2A n- 1M n X 3n+1 , where R is an organic amine ion with a larger ionic radius, A is Cs + , methylammonium ion (MA + ), or formamidinium ion (FA + ) and other smaller ions, M is Pb 2+ or Sn 2+ , and X is a halogen ion (Cl - , Br - , and I - ). In recent years, the performance of quasi-2D perovskite solar cells has been continuously improved, and the photoelectric conversion efficiency has rapidly developed from 4.73% to more than 20%. However, the efficiency of quasi-2D perovskite cells is still much lower than that of the corresponding 3D perovskites. Therefore, further improving the efficiency while maintaining stability is the key issue facing the research of quasi-2D perovskite solar cells.

[0004] Among 3D perovskites, the formamidinium-based perovskite FAPbI3 has a smaller band gap and higher thermal stability than the methylamine-based perovskite MAPbI3. Therefore, replacing the methylamine group in the quasi-2D perovskite material with a formamidinium group is expected to reduce the band gap of the 2D perovskite, further increase the photocurrent, and thus obtain a higher photoelectric conversion efficiency. However, FAPbI3 will transform from the photoactive black phase (α phase) to the non-photoactive yellow phase (δ phase) at room temperature, which will cause material degradation and battery performance attenuation. Therefore, the acquisition of a stable α-phase formamidinium-based two-dimensional perovskite is the key to preparing efficient quasi-two-dimensional perovskites. The organic macromolecules currently used are mostly organic amines with symmetrical structures. The quasi-two-dimensional perovskite films prepared based on this have mostly unoriented growth crystals, and the α phase is unstable and easily transformed into a yellow phase, which reduces the stability of the film and the efficiency of the device. Summary of the Invention

[0005] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a chiral quasi-two-dimensional formamidinium-based perovskite solar cell and its preparation method and application, so as to solve the technical problem that formamidinium-based two-dimensional perovskite films are easily converted into yellow non-perovskite phases, resulting in reduced film stability and device efficiency.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention discloses a method for preparing a chiral quasi-two-dimensional formamidinium-based perovskite solar cell, comprising the following steps:

[0008] S1: Mixing fatty acids and chiral amine molecules and subjecting them to a one-step acid-base reaction to obtain a chiral pseudohalogenamine salt; dissolving the chiral pseudohalogenamine salt, lead iodide, and formamidine iodide and cesium iodide in an N,N-dimethylacetamide solution and stirring to obtain a perovskite precursor solution;

[0009] S2: Coating a hole transport material on the surface of a conductive glass to obtain a conductive glass having a hole transport layer; coating a perovskite precursor solution on the surface of the conductive glass having a hole transport layer, followed by heat treatment to obtain a conductive glass having an active layer; coating an electron transport layer, a modification layer and a metal electrode in sequence on the surface of the conductive glass having an active layer to obtain a chiral quasi-two-dimensional formamidinium-based perovskite solar cell.

[0010] Furthermore, in S1, the fatty acid is any one of formic acid, acetic acid, propionic acid and acrylic acid; the chiral amine molecule is any one of S-1-phenylethylamine, R-1-phenylethylamine, R-1-(4-fluorophenyl)ethylamine or S-1-(4-fluorophenyl)ethylamine;

[0011] The preparation method of the chiral pseudohalogenamine salt is as follows: a chiral amine molecule and a fatty acid are mixed in a molar ratio of (1:1) to (1:1.2), stirred in an ice-water bath for 2 hours, and then subjected to a one-step acid-base reaction to obtain the chiral pseudohalogenamine salt.

[0012] Furthermore, in S1, the stoichiometric ratio of the chiral pseudohalogenamine salt, lead iodide, and formamidine iodine is according to the general structural formula R2(FA): n-1 Pb n X 3n+1 Select, wherein R represents a chiral amine molecule, n=3, 4 or 5; the mass concentration of the perovskite precursor solution is 200mL~300mg / mL.

[0013] Furthermore, in S1, the amount of cesium iodide used is 3 mg to 7 mg.

[0014] Furthermore, in S2, the type of the conductive glass is ITO conductive glass or FTO conductive glass; the hole transport material is PEDOT:PSS; the method of coating the hole transport material is spin coating, and the spin coating parameters are: spin coating speed of 5000 rad / min, time of 50s; after coating the hole transport material on the surface of the ITO conductive glass or FTO conductive glass, it is annealed at 150°C for 20 minutes.

[0015] Furthermore, in S2, the method of coating the perovskite precursor solution is heated spin coating, and the temperature of heated spin coating is 100°C to 150°C; the method of heat treatment is annealing, and the temperature of annealing is 110°C to 150°C, and the time is 4min to 10min.

[0016] Furthermore, in S2, the electron transport layer is PCBM; the specific steps of coating the electron transport layer are: dissolving PCBM in chlorobenzene, stirring at room temperature for 10 hours to obtain a mixed solution, and coating the mixed solution on the surface of the conductive glass having the active layer by spin coating, and the spin coating conditions are first spinning at a speed of 1000 rad / min for 50 seconds; then, spinning at a speed of 3000 rad / min for 5 seconds.

[0017] Furthermore, in S2, the modification layer is BCP, and the metal electrode is Ag; the thickness of the modification layer is 6 nm, and the thickness of the metal electrode is 120 nm; and the coating method of the modification layer and the metal electrode is evaporation.

[0018] The present invention also discloses a chiral quasi-two-dimensional formamidinium-based perovskite solar cell prepared by the above preparation method.

[0019] The present invention also discloses the application of the chiral quasi-two-dimensional formamidinium-based perovskite solar cell in the optoelectronic field.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention discloses a method for preparing a chiral quasi-two-dimensional formamidinium-based perovskite solar cell. The method utilizes an asymmetric chiral organic amine as a spacer cation of the quasi-two-dimensional perovskite solar cell to form a one-dimensional perovskite, stabilizes the α-phase formamidinium perovskite, and passivates the perovskite in situ, thereby realizing a high-efficiency and high-stability quasi-two-dimensional perovskite solar cell and tapping into the great potential of chiral organic amine molecules in the perovskite field. Furthermore, the one-dimensional perovskite phase is formed in situ, thereby enhancing the absorption of the perovskite cell in the ultraviolet region and improving the photoelectric conversion efficiency. The preparation method disclosed by the present invention has simple steps, does not require an anti-solvent, can be completed in air, has strong repeatability, and has broad application prospects.

[0022] The present invention also discloses a chiral quasi-two-dimensional formamidinium-based perovskite solar cell prepared by the above-mentioned preparation method. Based on the chiral amine molecules, a high-efficiency and high-stability quasi-two-dimensional perovskite solar cell is obtained, which enhances the absorption of the perovskite cell in the ultraviolet region and improves the photoelectric conversion efficiency. The ultraviolet light stability of the perovskite cell is also greatly improved, and it has a good application prospect.

[0023] The present invention also discloses the application of the above-mentioned chiral quasi-two-dimensional formamidinium-based perovskite solar cell. After the process parameters are optimized, in the absence of other additives, relevant experimental results show that the prepared formamidinium-based two-dimensional perovskite solar cell device has a photoelectric conversion efficiency of >20%, further improving the efficiency while maintaining stability, greatly promoting the commercialization process of perovskite solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is an SEM image of the chiral quasi-two-dimensional formamidinium-based perovskite film prepared in the present invention;

[0025] Figure 2 The UV-visible absorption spectra of chiral quasi-two-dimensional formamidinium-based perovskite films with different n values ​​(n=3, 4, 5) prepared by the present invention;

[0026] Figure 3 This is a structural diagram of the chiral quasi-two-dimensional formamidinium-based perovskite solar cell prepared by the present invention;

[0027] Figure 4 This is a forward and reverse scan JV curve diagram of the chiral quasi-two-dimensional formamidinium-based perovskite solar cell (n=4) prepared by the present invention. DETAILED DESCRIPTION

[0028] To facilitate understanding of the features and effects of the present invention by those skilled in the art, the following provides a general description and definition of the terms and expressions used in the specification and claims. Unless otherwise indicated, all technical and scientific terms used herein have the ordinary meanings as understood by those skilled in the art regarding the present invention. In the event of conflict, the definitions in this specification shall prevail.

[0029] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0030] Herein, all features such as values, amounts, amounts, and concentrations defined in numerical ranges or percentage ranges are for brevity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to include and specifically disclose all possible subranges and individual values ​​within the range (including integers and fractions).

[0031] In this document, unless otherwise specified, “include,” “including,” “contains,” “has” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0032] In this document, for the sake of brevity, not all possible combinations of the various technical features in each embodiment or example are described. Therefore, as long as there are no contradictions in the combination of these technical features, the various technical features in each embodiment or example can be combined in any way, and all possible combinations should be considered to be within the scope of this specification.

[0033] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0034] The following examples were prepared using conventional instruments and equipment in the art. Experimental methods in the following examples, where specific conditions are not specified, were generally performed under conventional conditions or according to the conditions recommended by the manufacturer. The various raw materials used in the following examples, unless otherwise specified, were conventional commercially available products, with specifications conventional in the art. In the present specification and the following examples, unless otherwise specified, "%" indicates percentage by weight, "part" indicates parts by weight, and "ratio" indicates weight ratio.

[0035] Example 1

[0036] A method for preparing a chiral quasi-two-dimensional formamidinium-based perovskite solar cell (n=4) comprises the following steps:

[0037] Step 1: Place 1.85 ml of R-1-phenylethylamine in a round-bottom flask in an ice-water bath, and slowly add 1.1 ml of acrylic acid dropwise thereto. Stir in the ice-water bath for 2 hours, then rotary evaporate at 55°C until no liquid drops. Place in a refrigerator for freezing and crystallization, then wash with ether, and then vacuum dry at 25°C to obtain a chiral pseudohalogenamine salt (R-PEAAA); according to the structural formula R2(FA) n- 1Pb n I 3n+1 (R, chiral amine molecule, n = 4) Weigh 130.91 mg of lead iodide, 61 mg of formamidinium iodide, 27.78 mg of R-PEAAA salt, and 3 mg of cesium iodide, dissolve them in 0.9 ml of DMAC (N,N-dimethylacetamide) organic solvent, and stir at 60°C for 6 hours until completely dissolved to obtain a perovskite precursor solution with a concentration of 220 mg / ml;

[0038] Step 2: Clean the ITO conductive glass by ultrasonicating it in ethanol, detergent, ultrapure water, acetone, and ethanol for 15 minutes each, then blow it dry with nitrogen, place it in an oven at 100°C for 30 minutes, and then treat it in a UV ozone environment for 15 minutes to obtain the treated ITO conductive glass; take the hole transport material PEDOT:PSS 45μL was dropped onto the treated ITO conductive glass, and a spin coater was used to form a film, and the speed was 5000rad / min for 50s; then the ITO coated with PEDOT:PSS was annealed at 150℃ for 20min to obtain an ITO conductive glass with a hole transport layer; the ITO conductive glass with a hole transport layer was placed on a heated spin coater and preheated for 3min, 25μL of the perovskite precursor solution was dropped onto the preheated ITO substrate, and a film was formed by spin coating at a spin coating temperature of 135℃, and then annealed at 135℃ for 8min to obtain an ITO conductive glass with an active layer; spin-coated perovskite The precursor solution was spin-coated at a rotation speed of 4000 rad / min for 20 seconds; 18 mg of PCBM was weighed and completely dissolved in 1 ml of chlorobenzene solvent, and stirred at 25°C for 10 hours to obtain a mixed solution, which was spin-coated on the surface of the ITO conductive glass with an active layer. When spin-coating PCBM, a rotation speed of 1000 rad / min was used for 50 seconds, and then 3000 rad / min was used for 5 seconds to form an electron transport layer. Subsequently, a vacuum evaporation technology was used to evaporate 6 nm of BCP on the electron transport layer, and then a 120 nm metal electrode Ag was evaporated to obtain a chiral quasi-two-dimensional formamidinium-based perovskite solar cell.

[0039] Under standard test conditions (AM1.5G illumination), the performance parameters of the quasi-two-dimensional perovskite solar cell device based on chiral organic amine prepared in this example are: energy conversion efficiency of 20.68%, open circuit voltage of 1.11V, and short circuit current of 23.67mA / cm 2 , the filling factor is 78.23%.

[0040] Example 2

[0041] A method for preparing a chiral quasi-two-dimensional formamidinium-based perovskite solar cell (n=4) comprises the following steps:

[0042] Step 1: Place 1.85 ml of S-1-phenylethylamine in a round-bottom flask in an ice-water bath, and slowly add 1.1 ml of acrylic acid dropwise thereto. Stir in the ice-water bath for 2 hours, then rotary evaporate at 55°C until no liquid drops. Place in a refrigerator for freezing and crystallization, then wash with ether, and then vacuum dry at 25°C to obtain chiral pseudohalogenamine salt (S-PEAAA); according to the structural formula R2(FA) n- 1Pb n I 3n+1 (R, chiral amine molecule, n = 4) Weigh 130.91 mg of lead iodide, 61 mg of formamidinium iodide, 27.78 mg of S-PEAAA salt, and 3 mg of cesium iodide, dissolve them in 0.9 ml of DMAC (N,N-dimethylacetamide) organic solvent, and stir at 60°C for 6 hours until completely dissolved to obtain a perovskite precursor solution with a concentration of 220 mg / ml;

[0043] Step 2: Clean the ITO conductive glass by ultrasonicating it in ethanol, detergent, ultrapure water, acetone, and ethanol for 15 minutes each, then blow it dry with nitrogen, place it in an oven at 100°C for 30 minutes, and then treat it in a UV ozone environment for 15 minutes to obtain the treated ITO conductive glass; take the hole transport material PEDOT:PSS 45 μL was dropped onto the treated ITO conductive glass, and a spin coater was used to form a film, and the speed was 6000 rad / min for 60 seconds; the ITO coated with PEDOT:PSS was annealed at 150 ° C for 20 minutes to obtain an ITO conductive glass with a hole transport layer; the ITO conductive glass with a hole transport layer was placed on a heated spin coater and preheated for 3 minutes, 25 μL of the perovskite precursor solution was dropped onto the preheated ITO substrate, and a film was formed by spin coating at a spin coating temperature of 135 ° C, and then annealed at 135 ° C for 8 minutes to obtain an ITO conductive glass with an active layer; the perovskite precursor was spin-coated The driving solution was spin-coated at a rotation speed of 4000 rad / min for 20 seconds; 18 mg of PCBM was weighed and completely dissolved in 1 ml of chlorobenzene solvent, and stirred at 25°C for 10 hours to obtain a mixed solution, which was spin-coated on the surface of the ITO conductive glass with an active layer. When spin-coating PCBM, a rotation speed of 1000 rad / min was used for 50 seconds, and then 3000 rad / min was used for 5 seconds to form an electron transport layer. Subsequently, a vacuum evaporation technology was used to evaporate 6 nm of BCP on the electron transport layer, and then a 120 nm metal electrode Ag was evaporated to obtain a chiral quasi-two-dimensional formamidinium-based perovskite solar cell.

[0044] Under standard test conditions (AM1.5G illumination), the performance parameters of the quasi-two-dimensional perovskite solar cell device based on chiral organic amine prepared in this example are: energy conversion efficiency of 20.33%, open circuit voltage of 1.10V, and short circuit current of 23.38mA / cm 2 , the filling factor is 78.61%.

[0045] Example 3

[0046] A method for preparing a chiral quasi-two-dimensional formamidinium-based perovskite solar cell (n=5) comprises the following steps:

[0047] Step 1: Place 1.85 ml of R-1-phenylethylamine in a round-bottom flask in an ice-water bath, and slowly add 1.1 ml of acrylic acid dropwise thereto. Stir in the ice-water bath for 2 hours, then rotary evaporate at 55°C until no liquid drops. Place in a refrigerator for freezing and crystallization, then wash with ether, and then vacuum dry at 25°C to obtain a chiral pseudohalogenamine salt (R-PEAAA); according to the structural formula R2(FA) n- 1Pb n I 3n+1(R, chiral amine molecule, n = 5) Weigh 134.45 mg of lead iodide, 61 mg of formamidinium iodide, 22.77 mg of R-PEAAA salt, and 6 mg of cesium iodide, dissolve them in 0.9 ml of DMAC (N,N-dimethylacetamide) organic solvent, and stir at 60°C for 6 hours until completely dissolved to obtain a perovskite precursor solution with a concentration of 230 mg / ml;

[0048] Step 2: Clean the ITO conductive glass by ultrasonicating it in ethanol, detergent, ultrapure water, acetone, and ethanol for 15 minutes each, then blow it dry with nitrogen, place it in an oven at 100°C for 30 minutes, and then treat it in a UV ozone environment for 15 minutes to obtain the treated ITO conductive glass; take the hole transport material PEDOT:PSS 45 μL was dropped onto the treated ITO conductive glass, and a spin coater was used to form a film, and the speed was 5000 rad / min for 50 seconds; the ITO coated with PEDOT:PSS was annealed at 150 ° C for 20 minutes to obtain an ITO conductive glass with a hole transport layer; the ITO conductive glass with a hole transport layer was placed on a heated spin coater and preheated for 3 minutes, 25 μL of the perovskite precursor solution was dropped onto the preheated ITO substrate, and a film was formed by spin coating at a spin coating temperature of 135 ° C, and then annealed at 135 ° C for 8 minutes to obtain an ITO conductive glass with an active layer; the perovskite precursor was spin-coated The driving solution was spin-coated at a rotation speed of 4000 rad / min for 20 seconds; 18 mg of PCBM was weighed and completely dissolved in 1 ml of chlorobenzene solvent, and stirred at 25°C for 10 hours to obtain a mixed solution, which was spin-coated on the surface of the ITO conductive glass with an active layer. When spin-coating PCBM, a rotation speed of 1000 rad / min was used for 50 seconds, and then 3000 rad / min was used for 5 seconds to form an electron transport layer. Subsequently, a vacuum evaporation technology was used to evaporate 6 nm of BCP on the electron transport layer, and then a 120 nm metal electrode Ag was evaporated to obtain a chiral quasi-two-dimensional formamidinium-based perovskite solar cell.

[0049] Under standard test conditions (AM1.5G illumination), the performance parameters of the quasi-two-dimensional perovskite solar cell device based on chiral organic amine prepared in this example are: energy conversion efficiency of 20.19%, open circuit voltage of 1.11V, and short circuit current of 23.15mA / cm 2 , the filling factor is 78.09%.

[0050] Example 4

[0051] A method for preparing a chiral quasi-two-dimensional formamidinium-based perovskite solar cell (n=5) comprises the following steps:

[0052] Step 1: Place 1.85 ml of S-1-phenylethylamine in a round-bottom flask in an ice-water bath, and slowly add 1.1 ml of acrylic acid dropwise thereto. Stir in the ice-water bath for 2 hours, then rotary evaporate at 55°C until no liquid drops. Place in a refrigerator for freezing and crystallization, then wash with ether, and then vacuum dry at 25°C to obtain a chiral pseudohalogenamine salt (R-PEAAA); according to the structural formula R2(FA) n- 1Pb n I 3n+1 (R, chiral amine molecule, n = 5) Weigh 134.45 mg of lead iodide, 61 mg of formamidinium iodide, 22.77 mg of R-PEAAA salt, and 6 mg of cesium iodide, dissolve them in 0.9 ml of DMAC (N,N-dimethylacetamide) organic solvent, and stir at 60°C for 6 hours until completely dissolved to obtain a perovskite precursor solution with a concentration of 230 mg / ml;

[0053] Step 2: Clean the ITO conductive glass by ultrasonicating it in ethanol, detergent, ultrapure water, acetone, and ethanol for 15 minutes each, then blow it dry with nitrogen, place it in an oven at 100°C for 30 minutes, and then treat it in a UV ozone environment for 15 minutes to obtain the treated ITO conductive glass; take the hole transport material PEDOT:PSS 45 μL was dropped onto the treated ITO conductive glass, and a spin coater was used to form a film, and the speed was 5000 rad / min for 50 seconds; the ITO coated with PEDOT:PSS was annealed at 150 ° C for 20 minutes to obtain an ITO conductive glass with a hole transport layer; the ITO conductive glass with a hole transport layer was placed on a heated spin coater and preheated for 3 minutes, 25 μL of the perovskite precursor solution was dropped onto the preheated ITO substrate, and a film was formed by spin coating at a spin coating temperature of 135 ° C, and then annealed at 135 ° C for 8 minutes to obtain an ITO conductive glass with an active layer; the perovskite precursor was spin-coated The body solution was spin-coated at a rotation speed of 4000 rad / min for 20 seconds; 18 mg of PCBM was weighed and completely dissolved in 1 mL of chlorobenzene solvent, and stirred at 25°C for 10 hours to obtain a mixed solution. The mixed solution was spin-coated on the surface of the ITO conductive glass with an active layer. When spin-coating PCBM, a rotation speed of 1000 rad / min was used for 50 seconds, and then 3000 rad / min was used for 5 seconds to form an electron transport layer. Subsequently, a vacuum evaporation technology was used to evaporate 6 nm of BCP on the electron transport layer, and then a 120 nm metal electrode Ag was evaporated to obtain a chiral quasi-two-dimensional formamidinium-based perovskite solar cell.

[0054] Under standard test conditions (AM1.5G illumination), the performance parameters of the quasi-two-dimensional perovskite solar cell device based on chiral organic amine prepared in this example are: energy conversion efficiency of 20.21%, open circuit voltage of 1.10V, and short circuit current of 23.42mA / cm2 , the filling factor is 78.37%.

[0055] Example 5

[0056] A method for preparing a chiral quasi-two-dimensional formamidinium-based perovskite solar cell (n=4) comprises the following steps:

[0057] Step 1: Place 2.36 ml of S-1-(4-fluorophenyl)ethylamine in a round-bottom flask in an ice-water bath, and slowly add 1.1 ml of acetic acid dropwise thereto. After stirring in an ice-water bath for 2 hours, evaporate at 55°C until no liquid drops, freeze and crystallize in a refrigerator, then wash with ether, and then vacuum dry at 25°C to obtain a chiral pseudohalogenamine salt (S-FPEAAc); according to the structural formula R2(FA) n-1 Pb n I 3n+1 (R, chiral amine molecule, n = 4) Weigh 134 mg of lead iodide, 61 mg of formamidinium iodide, 29 mg of S-FPEAAc salt, and 5 mg of cesium iodide, dissolve them in 0.65 ml of DMAC (N,N-dimethylacetamide) organic solvent, and stir at 60°C for 6 hours until completely dissolved to obtain a perovskite precursor solution with a concentration of 300 mg / ml;

[0058] Step 2: Clean the ITO conductive glass by ultrasonicating it in ethanol, detergent, ultrapure water, acetone, and ethanol for 15 minutes each, then blow it dry with nitrogen, place it in an oven at 100°C for 30 minutes, and then treat it in a UV ozone environment for 15 minutes to obtain the treated ITO conductive glass; take the hole transport material PEDOT:PSS 45μL was dropped onto the treated ITO conductive glass, and a spin coater was used to form a film, and the speed was 5000rad / min for 50s; then the ITO coated with PEDOT:PSS was annealed at 150℃ for 20min to obtain an ITO conductive glass with a hole transport layer; the ITO conductive glass with a hole transport layer was placed on a heated spin coater and preheated for 3min, 25μL of the perovskite precursor solution was dropped onto the preheated ITO substrate, and a film was formed by spin coating at a spin coating temperature of 100℃, and then annealed at 140℃ for 10min to obtain an ITO conductive glass with an active layer; spin-coated perovskite The precursor solution was spin-coated at a rotation speed of 4000 rad / min for 20 seconds; 18 mg of PCBM was weighed and completely dissolved in 1 ml of chlorobenzene solvent, and stirred at 25°C for 10 hours to obtain a mixed solution, which was spin-coated on the surface of the ITO conductive glass with an active layer. When spin-coating PCBM, a rotation speed of 1000 rad / min was used for 50 seconds, and then 3000 rad / min was used for 5 seconds to form an electron transport layer. Subsequently, a vacuum evaporation technology was used to evaporate 6 nm of BCP on the electron transport layer, and then a 120 nm metal electrode Ag was evaporated to obtain a chiral quasi-two-dimensional formamidinium-based perovskite solar cell.

[0059] Under standard test conditions (AM1.5G illumination), the performance parameters of the quasi-two-dimensional perovskite solar cell device based on chiral organic amine prepared in this example are: energy conversion efficiency of 16.85%, open circuit voltage of 1.03V, and short circuit current of 20.34mA / cm 2 , the filling factor is 80.75%.

[0060] Example 6

[0061] A method for preparing a chiral quasi-two-dimensional formamidinium-based perovskite solar cell (n=4) comprises the following steps:

[0062] Step 1: Place 1.8 ml of R-1-(4-fluorophenyl)ethylamine in a round-bottom flask in an ice-water bath, and slowly add 1.1 ml of propionic acid thereto. Stir in the ice-water bath for 2 hours, then rotary evaporate at 55°C until no liquid drops. Place in a refrigerator to freeze and crystallize, then wash with ether, and then vacuum dry at 25°C to obtain a chiral pseudohalogenamine salt (R-FPEAPA); according to the structural formula R2(FA) n-1 Pb n I3 n+1(R, chiral amine molecule, n = 4) Weigh 134 mg of lead iodide, 61 mg of formamidinium iodide, 29 mg of R-FPEAPA salt, and 7 mg of cesium iodide, dissolve them in 1 ml of DMAC (N,N-dimethylacetamide) organic solvent, and stir at 60°C for 6 hours until completely dissolved to obtain a perovskite precursor solution with a concentration of 200 mg / ml;

[0063] Step 2: Clean the ITO conductive glass by ultrasonicating it in ethanol, detergent, ultrapure water, acetone, and ethanol for 15 minutes each, then blow it dry with nitrogen, place it in an oven at 100°C for 30 minutes, and then treat it in a UV ozone environment for 15 minutes to obtain the treated ITO conductive glass; take the hole transport material PEDOT:PSS 45μL was dropped onto the treated ITO conductive glass, and a spin coater was used to form a film, and the speed was 5000rad / min for 50s; then the ITO coated with PEDOT:PSS was annealed at 150℃ for 20min to obtain an ITO conductive glass with a hole transport layer; the ITO conductive glass with a hole transport layer was placed on a heated spin coater and preheated for 3min, 25μL of the perovskite precursor solution was dropped onto the preheated ITO substrate, and a film was formed by spin coating at a spin coating temperature of 150℃, and then annealed at 150℃ for 5min to obtain an ITO conductive glass with an active layer; spin-coated perovskite The precursor solution was spin-coated at a rotation speed of 4000 rad / min for 20 seconds; 18 mg of PCBM was weighed and completely dissolved in 1 ml of chlorobenzene solvent, and stirred at 25°C for 10 hours to obtain a mixed solution, which was spin-coated on the surface of the ITO conductive glass with an active layer. When spin-coating PCBM, a rotation speed of 1000 rad / min was used for 50 seconds, and then 3000 rad / min was used for 5 seconds to form an electron transport layer. Subsequently, a vacuum evaporation technology was used to evaporate 6 nm of BCP on the electron transport layer, and then a 120 nm metal electrode Ag was evaporated to obtain a chiral quasi-two-dimensional formamidinium-based perovskite solar cell.

[0064] Under standard test conditions (AM1.5G illumination), the performance parameters of the quasi-two-dimensional perovskite solar cell device based on chiral organic amine prepared in this example are: energy conversion efficiency of 17.2%, open circuit voltage of 1.04V, and short circuit current of 21.14mA / cm 2 , the filling factor is 78.68%.

[0065] Example 7

[0066] A method for preparing a chiral quasi-two-dimensional formamidinium-based perovskite solar cell (n=3) comprises the following steps:

[0067] Step 1: Place 1.85 ml of S-1-phenylethylamine in an ice-water bath in a round-bottom flask, and slowly add 1.1 ml of acrylic acid thereto. After stirring in an ice-water bath for 2 hours, evaporate at 55°C until no liquid drops, freeze and crystallize in a refrigerator, then wash with ether, and then vacuum dry at 25°C to obtain a chiral pseudohalogenamine salt (S-PEAAA); according to the structural formula R2(FA)n-1PbnI3n+1 (R, chiral amine molecule, n=4), weigh 125 mg of lead iodide, 61 mg of formamidine iodine, 33.8 mg of S-PEAAA salt, and 5 mg of cesium iodide, dissolve them in 1 ml of DMAC (N,N-dimethylacetamide) organic solvent, and stir at 60°C for 6 hours until completely dissolved to obtain a perovskite precursor solution with a concentration of 200 mg / ml;

[0068] Step 2: Clean the ITO conductive glass by ultrasonicating it in ethanol, detergent, ultrapure water, acetone, and ethanol for 15 minutes each, then blow it dry with nitrogen, place it in an oven at 100°C for 30 minutes, and then treat it in a UV ozone environment for 15 minutes to obtain the treated ITO conductive glass; take the hole transport material PEDOT:PSS 45μL was dropped onto the treated ITO conductive glass, and a spin coater was used to form a film, and the speed was 5000rad / min for 50s; then the ITO coated with PEDOT:PSS was annealed at 150℃ for 20min to obtain an ITO conductive glass with a hole transport layer; the ITO conductive glass with a hole transport layer was placed on a heated spin coater and preheated for 3min, 25μL of the perovskite precursor solution was dropped onto the preheated ITO substrate, and a film was formed by spin coating at a spin coating temperature of 100℃, and then annealed at 135℃ for 8min to obtain an ITO conductive glass with an active layer; spin-coated perovskite The precursor solution was spin-coated at a rotation speed of 4000 rad / min for 20 seconds; 18 mg of PCBM was weighed and completely dissolved in 1 ml of chlorobenzene solvent, and stirred at 25°C for 10 hours to obtain a mixed solution, which was spin-coated on the surface of the ITO conductive glass with an active layer. When spin-coating PCBM, a rotation speed of 1000 rad / min was used for 50 seconds, and then 3000 rad / min was used for 5 seconds to form an electron transport layer. Subsequently, a vacuum evaporation technology was used to evaporate 6 nm of BCP on the electron transport layer, and then a 120 nm metal electrode Ag was evaporated to obtain a chiral quasi-two-dimensional formamidinium-based perovskite solar cell.

[0069] Under standard test conditions (AM1.5G illumination), the performance parameters of the quasi-two-dimensional perovskite solar cell device based on chiral organic amine prepared in this example are: energy conversion efficiency of 14.45%, open circuit voltage of 1.04V, short circuit current of 18mA / cm 2 , the filling factor is 76.6%.

[0070] Comparative Example 1

[0071] The comparative example is a quasi-two-dimensional perovskite solar cell (n=4) prepared based on a symmetrical non-chiral organic amine, which mainly includes the following steps:

[0072] Step 1: 2.2 ml of phenylethylamine was placed in a round-bottom flask in an ice-water bath, and 1.1 ml of acrylic acid was slowly added dropwise thereto. After stirring in the ice-water bath for 2 hours, the mixture was evaporated at 55°C until no liquid droplets were left. The mixture was placed in a refrigerator for freezing and crystallization, and then washed with ether and dried in a vacuum oven at 25°C to obtain phenylethylamine acrylate (PEAAA) solid. According to the structural formula R2(FA) n-1 Pb n I 3n+1 (R, achiral amine molecule, n = 4) Weigh 130.91 mg of lead iodide, 61 mg of formamidinium iodide, 27.78 mg of PEAAA salt, and 3 mg of cesium iodide, dissolve them in 0.9 ml of DMAC organic solvent, and stir at 60°C for 6 hours until completely dissolved to prepare a perovskite precursor solution with a concentration of 220 mg / ml;

[0073] Step 2: Clean the ITO conductive glass in the following order: ethanol, detergent, ultrapure water, and acetone. Ultrasonicate in ethanol for 15 minutes each, blow dry with nitrogen, and dry in a 100°C oven for 30 minutes. Then, treat the cleaned ITO substrate with UV ozone for 15 minutes, take 45μL of hole transport material PEDOT:PSS and drop it on the treated ITO substrate. Use a spin coater to spin-coat it into a film at a speed of 5000 revolutions per minute for 50 seconds. Then, anneal the ITO coated with PEDOT:PSS at 150°C for 20 minutes. Place the annealed ITO conductive substrate coated with a hole transport layer on a heated spin coater and preheat for 3 minutes. Take 25μL of the preheated perovskite precursor solution on the ITO substrate, spin-coat it into a film, and then anneal it to form a perovskite film. The speed of spin-coating the perovskite precursor solution is 4000 revolutions per minute for 20 seconds. , annealed at 135°C in air for 8 minutes to obtain a conductive glass with an active layer; then 18 mg of PCBM was weighed and completely dissolved in 1 ml of chlorobenzene solvent, stirred at 25°C for 10 hours to obtain a mixed solution, and the mixed solution was spin-coated onto the perovskite film. The PCBM was spin-coated at 1000 revolutions per minute for 50 seconds, and then at 3000 revolutions per minute for 5 seconds to form an electron transport layer. Using vacuum evaporation technology, 6 nm of BCP was evaporated on the electron transport layer, and then 120 nm of metal electrode Ag was evaporated to obtain a perovskite solar cell.

[0074] Under standard test conditions (AM1.5G illumination), the performance parameters of the quasi-two-dimensional perovskite solar cell device based on non-chiral organic amine prepared in this comparative example are: energy conversion efficiency of 15.96%, open circuit voltage of 1.02V, short circuit current of 20.87mA / cm 2 , the filling factor is 75.2%;

[0075] Comparative Example 2

[0076] The comparative example is a quasi-two-dimensional perovskite solar cell (n=5) prepared based on a symmetrical non-chiral organic amine, which mainly includes the following steps:

[0077] Step 1: Take 2.2 ml of phenylethylamine and place it in an ice-water bath in a round-bottom flask. Slowly add 1.1 ml of acrylic acid dropwise thereto. Stir in the ice-water bath for 2 hours. Rotary evaporate at 55°C until no liquid drops. Place in a refrigerator to freeze and crystallize. Wash with ether and dry in a vacuum oven at 25°C to obtain phenylethylamine acrylate (PEAAA) solid. According to the structural formula R2(FA) n-1 Pb n I 3n+1 (R, achiral amine molecule, n = 5) Weigh 134.45 mg of lead iodide, 61 mg of formamidinium iodide, 22.77 mg of achiral PEAAA salt, and 3 mg of cesium iodide, dissolve them in 0.9 ml of DMAC organic solvent, and stir at 60°C for 6 hours until completely dissolved to prepare a perovskite precursor solution with a concentration of 230 mg / ml;

[0078] Step 2: Clean the ITO conductive glass in the following order: ethanol, detergent, ultrapure water, and acetone. Ultrasonicate in ethanol for 15 minutes, blow dry with nitrogen, and dry in a 100°C oven for 30 minutes. Then, treat with UV ozone for 15 minutes to obtain the treated ITO conductive glass. Take 45 μL of the hole transport material PEDOT:PSS and drop it onto the treated ITO substrate. Use a spin coater to spin-coat the film at a speed of 5000 rpm for 50 seconds. Then, spin-coat the ITO with PEDOT:PSS. Anneal at 150°C for 20 minutes; place the annealed ITO conductive substrate with a hole transport layer on a heated spin coater and preheat for 3 minutes, then drop 25 μL of the perovskite precursor solution onto the preheated ITO substrate, spin-coat it into a film, and then anneal it to form a perovskite film; the spin-coating speed of the perovskite precursor solution is 4000 revolutions per minute for 20 seconds, and anneal it at 135°C in air for 8 minutes; then weigh 18 mg of PCBM, dissolve it completely in 1 ml of chlorobenzene solvent, stir it at 25°C for 10 hours to obtain a mixed solution, and spin-coat the prepared electron transport mixed solution onto the perovskite film, spin-coating PCBM at 1000 revolutions per minute for 50 seconds, and then spin-coating at 3000 revolutions per minute for 5 seconds to form an electron transport layer; using vacuum evaporation technology, evaporate 6 nm of BCP on the electron transport layer, and then evaporate 120 nm of metal electrode Ag to obtain a perovskite solar cell.

[0079] Under standard test conditions (AM1.5G illumination), the performance parameters of the quasi-two-dimensional perovskite solar cell device based on non-chiral organic amine prepared in this comparative example are: energy conversion efficiency of 15.97%, open circuit voltage of 1.02V, short circuit current of 22.3mA / cm 2 , the filling factor is 69.6%.

[0080] Table 1 shows the performance comparison data of the chiral quasi-two-dimensional formamidinium-based perovskite solar cell prepared by the present invention and the perovskite solar cell of the comparative example. It can be seen from Table 1 that the open circuit voltage, short circuit current, fill factor and energy conversion efficiency of the chiral quasi-two-dimensional perovskite solar cell prepared by the present invention based on chiral organic amine are significantly better than those of the quasi-two-dimensional perovskite solar cell prepared by the control group based on symmetrical structure non-chiral organic amine, and have more excellent battery performance.

[0081] Table 1: Performance comparison of different titanium ore solar cells

[0082]

[0083] Figure 1 The figure shows an SEM image of the chiral quasi-two-dimensional formamidinium-based perovskite film prepared by the present invention. From the figure, it can be seen that the quasi-two-dimensional perovskite film prepared based on the chiral pseudohalogen salt has a large grain size; Figure 2Shown are the UV-visible absorption spectra of chiral quasi-two-dimensional formamidine-based perovskite films with different n values ​​(n=3, 4, 5) prepared by the present invention. From the figure, it can be seen that the quasi-two-dimensional chiral perovskite films prepared based on chiral pseudohalogen salts have a one-dimensional phase formation and have a high phase purity; Figure 3 The figure shows the structure of the chiral quasi-two-dimensional formamidine-based perovskite solar cell prepared by the present invention. It can be seen that the structure of the chiral quasi-two-dimensional formamidine-based perovskite solar cell prepared by the present invention is, from top to bottom, a metal electrode, a modification layer, an electron transport layer, a perovskite precursor solution, a hole transport layer, and an ITO conductive glass. Figure 4 Shown is the forward and reverse sweep JV curve of the chiral quasi-two-dimensional formamidinium-based perovskite solar cell (n=4) prepared by the present invention. From the figure, it can be seen that the quasi-two-dimensional chiral perovskite solar cell prepared based on chiral pseudohalogen salt has almost no hysteresis under forward and reverse sweeps.

[0084] The above content is only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a chiral quasi-two-dimensional formamidine-based perovskite solar cell, characterized in that: The following steps are involved: S1: Mixing fatty acids and chiral amine molecules and then subjecting them to a one-step acid-base reaction to obtain chiral pseudohalogenamine salts; Dissolving a chiral pseudohalogenamine salt, lead iodide, formamidine iodide, and cesium iodide in an N,N-dimethylacetamide solution and stirring to obtain a perovskite precursor solution; S2: coating a hole transport material on the surface of the conductive glass to obtain a conductive glass having a hole transport layer; A perovskite precursor solution is coated on the surface of the conductive glass having the hole transport layer, followed by heat treatment to obtain the conductive glass having the active layer; An electron transport layer, a modification layer, and a metal electrode are sequentially coated on the surface of a conductive glass having an active layer to obtain a chiral quasi-two-dimensional formamidinium-based perovskite solar cell. In S1, the chiral amine molecule is any one of S-1-phenylethylamine, R-1-phenylethylamine, R-1-(4-fluorophenyl)ethylamine or S-1-(4-fluorophenyl)ethylamine.

2. The method for preparing a chiral quasi-two-dimensional formamidinium-based perovskite solar cell according to claim 1, characterized in that: In S1, the fatty acid is any one of formic acid, acetic acid, propionic acid and acrylic acid; The preparation method of the chiral pseudohalogenamine salt is as follows: a chiral amine molecule and a fatty acid are mixed in a molar ratio of (1:1) to (1:1.2), stirred in an ice-water bath for 2 hours, and then subjected to a one-step acid-base reaction to obtain the chiral pseudohalogenamine salt.

3. The method for preparing a chiral quasi-two-dimensional formamidinium-based perovskite solar cell according to claim 1, characterized in that: In S1, the stoichiometric ratio of the chiral pseudohalogenamine salt, lead iodide, and formamidine iodine is according to the general structural formula R2(FA): n- 1Pb n X 3n+1 Select, wherein R represents a chiral amine molecule, n=3, 4 or 5; the mass concentration of the perovskite precursor solution is 200mL~300mg / mL.

4. The method for preparing a chiral quasi-two-dimensional formamidinium-based perovskite solar cell according to claim 1, characterized in that: In S1, the amount of cesium iodide used is 3 mg to 7 mg.

5. The method for preparing a chiral quasi-two-dimensional formamidinium-based perovskite solar cell according to claim 1, characterized in that: In S2, the type of the conductive glass is ITO conductive glass or FTO conductive glass; the hole transport material is PEDOT:PSS; the method of coating the hole transport material is spin coating, and the spin coating parameters are: spin coating speed of 5000 rad / min, time of 50s; after coating the hole transport material on the surface of the ITO conductive glass or FTO conductive glass, it is annealed at 150°C for 20 minutes.

6. The method for preparing a chiral quasi-two-dimensional formamidinium-based perovskite solar cell according to claim 1, characterized in that: In S2, the coating method of the perovskite precursor solution is heated spin coating, and the temperature of the heated spin coating is 100°C to 150°C; the heat treatment method is annealing, and the temperature of the annealing is 110°C to 150°C, and the time is 4 minutes to 10 minutes.

7. The method for preparing a chiral quasi-two-dimensional formamidinium-based perovskite solar cell according to claim 1, characterized in that: In S2, the electron transport layer is PCBM; the specific steps of coating the electron transport layer are: dissolving PCBM in chlorobenzene, stirring at room temperature for 10 hours to obtain a mixed solution, and coating the mixed solution on the surface of the conductive glass having the active layer by spin coating, and the spin coating conditions are first spinning at a speed of 1000 rad / min for 50 seconds; then, spinning at a speed of 3000 rad / min for 5 seconds.

8. The method for preparing a chiral quasi-two-dimensional formamidinium-based perovskite solar cell according to claim 1, characterized in that: In S2, the modification layer is BCP, and the metal electrode is Ag; the thickness of the modification layer is 6 nm, and the thickness of the metal electrode is 120 nm; and the coating method of the modification layer and the metal electrode is evaporation.

9. A chiral quasi-two-dimensional formamidinium-based perovskite solar cell prepared by the method for preparing a chiral quasi-two-dimensional formamidinium-based perovskite solar cell according to any one of claims 1 to 8.

10. Application of the chiral quasi-two-dimensional formamidinium-based perovskite solar cell according to claim 9 in the field of optoelectronics.

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