Perovskite cell and preparation method thereof

Abstract

The invention discloses a perovskite battery and a preparation method, and relates to the technical field of perovskite battery preparation. The perovskite cell comprises an electron transport layer and a perovskite light absorption layer, the electron transport layer comprises a first modifier, and functional groups in the first modifier comprise at least two of guanidyl, phenyl and cyano. The perovskite light absorption layer of the perovskite cell comprises a second modifier, and functional groups in the second modifier comprise at least two of carboxyl, phenyl and potassium ions. According to the invention, a mechanism of double modifiers is innovatively introduced, so that the energy conversion efficiency of the perovskite cell is remarkably improved; in addition, the addition of the modifier can effectively inhibit the degradation of the perovskite material, thereby improving the long-term stability and service life of the perovskite battery. The preparation method of the perovskite cell is simple and easy to implement, facilitates reduction of the production cost, and has a good industrial application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of perovskite battery preparation, and in particular to a perovskite battery and a preparation method thereof. Background Art

[0002] Perovskite solar cells have attracted widespread attention due to their many advantages, such as high absorption coefficient, adjustable band gap, low exciton binding energy, long carrier diffusion radius, and solution processing. Perovskite materials play the main role in photoelectric conversion in perovskite solar cells. Therefore, existing perovskite solar cells mainly improve their energy conversion efficiency by optimizing the composition and structure of perovskite materials. The complexity of interface problems limits the ability of perovskite solar cells to further approach the theoretical limit efficiency, and also affects the stability of perovskite solar cells; perovskite materials are easy to decompose or deteriorate at high temperature and high humidity, resulting in the need to improve the long-term stability and service life of perovskite cells; the existing technology has insufficient research on the interface optimization of the electron transport layer and perovskite layer of perovskite cells; the existing technology mainly focuses on the electronic structure and crystal quality of perovskite materials, while the passivation of defects at the boundaries of perovskite grains is insufficient.

[0003] Therefore, it is necessary to conduct research specifically on the interface modification of perovskite cells and seek a technical solution that can significantly improve the long-term stability of perovskite cells while achieving good interface modification. Summary of the invention

[0004] The main purpose of the present invention is to develop a perovskite battery that can effectively solve the interface problem between the perovskite layer and the electron transport layer, the serious non-radiative recombination problem caused by internal defects of the perovskite material, and the long-term stability problem of the perovskite battery, thereby effectively improving the photoelectric conversion efficiency of the perovskite battery.

[0005] To achieve the above objectives, the present invention proposes a perovskite cell, which includes an electron transport layer and a perovskite light absorbing layer, wherein the electron transport layer includes a first modifier, and the functional groups in the first modifier include at least two of guanidine, phenyl and cyano.

[0006] In one embodiment, in the electron transport layer, the first modifier includes p-guanidinobenzonitrile hydrochloride.

[0007] In one embodiment, the electron transport layer further includes a metal oxide, and the metal oxide includes at least one of SnO2, TiO2, ZnO, BaSnO3, and CeO2.

[0008] In one embodiment, the perovskite light absorbing layer includes a halide, and the halide includes at least one of CsI, CsBr, CsCl, KI, KBr, KCl, RbI, RbBr, RbCl, MAI, MABr, MACl, FABr, and FACl.

[0009] In one embodiment, the perovskite light absorbing layer includes a second modifier, and the functional groups in the second modifier include at least two of a carboxyl group, a phenyl group, and a potassium ion.

[0010] In one embodiment, the second modifier includes a carboxyl potassium salt, and the carboxyl potassium salt includes at least one of potassium cinnamate, potassium oxalate, and potassium pyromellitic acid.

[0011] The present invention also provides a method for preparing the perovskite battery, which comprises the following steps:

[0012] S1, dissolving the first modifier in an organic solvent to obtain an electron transport layer precursor solution, and subjecting the electron transport layer precursor solution to a deposition process to obtain the electron transport layer;

[0013] S2. Preparing the perovskite light-absorbing layer on the surface of the electron transport layer prepared in step S1 to prepare the perovskite cell.

[0014] In one embodiment, in step S1, the concentration of the first modifier in the solution is 0.25-2.0 mg / mL.

[0015] In one embodiment, in step S2, the perovskite light absorbing layer is prepared by depositing a perovskite precursor solution on the surface of the electron transport layer, wherein the concentration of the second modifier in the perovskite precursor solution is 5 to 10 mg / mL.

[0016] In one embodiment, in the step S1, the electron transport layer precursor solution further includes a metal oxide, and the mass fraction of the metal oxide in the solution is 3-5 wt%.

[0017] In one embodiment, in step S2, the concentration of the halide in the perovskite precursor solution is 1-3M.

[0018] In one embodiment, in the step S1, the electron transport layer is prepared by spin coating, wherein during the spin coating process, the rotation speed is 2500 rpm to 5000 rpm, and the time is 25s to 50s.

[0019] In one embodiment, in step S2, the perovskite light absorbing layer is prepared by spin coating, wherein the spin coating is firstly carried out at a rotation speed of 800 to 1500 rpm for 10 to 20 s, and then at a rotation speed of 2500 to 4000 rpm for 20 to 50 s.

[0020] In one embodiment, in the step S1, the first modifier and the metal oxide are dispersed in an organic solvent and stirred evenly to obtain the electron transport layer precursor solution, the electron transport layer precursor solution is transferred to the surface of the conductive glass, and annealed at 120 to 170° C. for 25 to 40 minutes to obtain the electron transport layer.

[0021] In one embodiment, in the step S2, the halide of the second modifier is dispersed in an organic solvent and stirred evenly to obtain the perovskite precursor solution, and the perovskite precursor solution is transferred to the surface of the electron transport layer prepared in the step S1, and annealed at 100° C. for 10 to 20 minutes to obtain the perovskite light absorbing layer.

[0022] The technical solution of the present invention designs a perovskite battery. Compared with the prior art, the present invention uses guanidine benzonitrile hydrochloride to modify the buried interface of the electron transport layer and the perovskite light absorption layer, and passivates the surface defects of the electron transport layer by coordination. At the same time, the present invention also introduces potassium cinnamate into the perovskite light absorption layer, which can in situ passivate the defects at the boundary of the perovskite grains and inhibit non-radiative recombination. The two mechanisms synergistically enhance the energy conversion efficiency of the perovskite battery. This design innovatively introduces the mechanism of dual modifiers, achieving a significant improvement in the energy conversion efficiency of the perovskite battery. In addition, the addition of modifiers can also effectively inhibit the degradation of perovskite materials, thereby improving the long-term stability and service life of the perovskite battery. Although the technical solution of the present invention uses two modifiers, the raw material cost is low, the preparation method is simple, and it is easy to implement, which is conducive to reducing production costs and has good industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0024] Figure 1 The current density-voltage curves of the perovskite cells prepared in Example 1 and Comparative Example 1;

[0025] Figure 2The current density-voltage curve comparison diagram of the perovskite battery prepared in Example 1 and Comparative Example 1 before and after storage for 7 days;

[0026] Figure 3 The current density-voltage curves of the perovskite cells prepared in Example 2 and Comparative Example 2;

[0027] Figure 4 The current density-voltage curve comparison diagram of the perovskite battery prepared in Example 2 and Comparative Example 2 before and after storage for 7 days;

[0028] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0031] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0032] The technical problems solved by the present application are: the complexity of interface problems limits the ability of perovskite solar cells to further approach the theoretical limit efficiency, while affecting the stability of perovskite solar cells; perovskite materials are easily decomposed or deteriorated at high temperature and high humidity, resulting in the need to improve the long-term stability and service life of perovskite cells; the prior art has insufficient research on the interface optimization of the electron transport layer and the perovskite layer of perovskite cells; the prior art mainly studies the electronic structure and crystal quality of perovskite materials, but insufficient research on the passivation of defects at the boundaries of perovskite grains.

[0033] In order to solve the above technical problems, a perovskite cell is designed that can effectively solve the interface problem between the perovskite layer and the electron transport layer, the serious problem of non-radiative recombination caused by internal defects of the perovskite material, and the long-term stability problem of the perovskite cell, thereby effectively improving the photoelectric conversion efficiency of the perovskite cell.

[0034] The present invention provides a perovskite battery, which includes an electron transport layer and a perovskite light absorption layer. The electron transport layer includes a first modifier, and the functional groups in the first modifier include at least two of guanidine, phenyl and cyanide.

[0035] It should be noted that the first modifier containing a guanidine group is added to the electron transport layer. The guanidine group in the first modifier is a multidentate ligand. The imine group of the guanidine group can coordinate with the insufficiently coordinated metal ions in the electron transport layer, passivate the defects inside the electron transport layer, and improve the electron transport efficiency; the phenyl group is a planar structure, and the conjugated system (large π bond) of the benzene ring itself has a high electron transport ability, which can passivate the defects inside the electron transport layer and at the interface between the electron transport layer and the perovskite layer, reduce non-radiative recombination, and contribute to the effective transmission of electrons; the cyanide group has a strong electron affinity and can form a strong chemical coordination with the metal ions in the electron transport layer, effectively passivate the defects, and form non-radiative recombination. In addition, the cyanide group is also easy to coordinate with the lead ions in the perovskite layer, promote the growth of perovskite grains, thereby passivating and modifying the interface; the cyanide group can also inhibit the oxidation and decomposition of the metal ions in the electron transport layer, which is beneficial to improve the long-term stability and service life of the perovskite battery.

[0036] In one embodiment, in the electron transport layer, the first modifier includes p-guanidinobenzonitrile hydrochloride.

[0037] It should be noted that p-guanidine benzonitrile hydrochloride is the hydrochloride form of p-guanidine benzonitrile. The first modifier is in the form of hydrochloride because in the preparation process of a conventional electron transport layer, a metal oxide dispersion is generally dispersed in water and then deposited. Therefore, using the hydrochloride form is beneficial to fully mix the first modifier with the metal oxide, thereby better performing the modification. p-guanidine benzonitrile hydrochloride contains guanidine, phenyl, cyano and chloride ions at the same time, wherein the guanidine and cyano groups are respectively located in the para position of the phenyl group, and the conjugated π bond of the benzene ring, the carbon-nitrogen double bond of the guanidine group and the carbon-nitrogen triple bond of the cyano group produce overlapping electron clouds that are easy to form a large conjugated structure, which is beneficial to passivating interface defects and reducing non-radiative recombination on the one hand; on the other hand, it makes the first modifier have better planarity, which is beneficial to the orderly arrangement of the first modifier in the electron transport layer and the interface, reducing defects and promoting the orderly growth and vertical crystal orientation of the perovskite material, thereby improving the performance of the perovskite battery.

[0038] In one embodiment, the electron transport layer also includes a metal oxide, and the metal oxide includes at least one of SnO2, TiO2, ZnO, BaSnO3, and CeO2; preferably, in one embodiment, the metal oxide includes SnO2; it should be noted that the conventional method for preparing the electron transport layer is to disperse the above-mentioned metal oxide in deionized water to form an electron transport precursor solution and then perform a deposition treatment, but there is a large interface energy barrier between the above-mentioned material and the perovskite material, which is not conducive to the efficient extraction and transmission of carriers. Therefore, the above-mentioned first modifier, especially p-guanidine benzonitrile hydrochloride, can solve this technical problem well. Its conjugated spatial structure, its own high electron transport ability, and the para-guanidine and cyanide groups provide active sites. These factors all give it a good bridging effect, which can effectively reduce the interface energy barrier and promote the transmission of carriers between the electron transport layer and the perovskite layer.

[0039] In one embodiment, the perovskite light absorbing layer includes a halide, and the halide includes at least one of CsI, CsBr, CsCl, KI, KBr, KCl, RbI, RbBr, RbCl, MAI, MABr, MACl, FABr, and FACl.

[0040] In one embodiment, the perovskite light absorbing layer includes a second modifier, and the functional groups in the second modifier include at least two of a carboxyl group, a phenyl group, and a potassium ion.

[0041] In one embodiment, the second modifier includes a carboxyl potassium salt, and the carboxyl potassium salt includes at least one of potassium cinnamate, potassium oxalate, and potassium pyromellitic acid.

[0042] It should be noted that the present invention uses a second modifier to modify and passivate the perovskite layer. The second modifier is preferably a carboxyl potassium salt, including polycarboxyl potassium salts and monocarboxyl potassium salts. Preferably, the carboxyl potassium salt includes potassium cinnamate, which is the potassium salt form of cinnamic acid and has phenyl, alkenyl, carboxyl and potassium ions. Compared with p-guanidinobenzonitrile hydrochloride, potassium cinnamate also has a conjugated system. Potassium cinnamate also has a good bridging effect and can perform molecular coordination to form "KI X Structure", "-COO-Pb structure" and the coordination effect of the carboxyl group with the metal ions in the electron transport layer at the interface, through the above-mentioned bridging effect, enhance the interface stability, which can improve the stability and photoelectric conversion efficiency of the perovskite battery.

[0043] It should also be noted that the present invention simultaneously uses p-guanidinobenzonitrile hydrochloride and potassium cinnamate, two modifiers with conjugated spatial structures, higher electron transport capabilities and more active sites, to modify and passivate the electron transport layer, perovskite layer and the interface between the two of the perovskite battery, respectively. In terms of coordination, it can passivate defect sites, change internal defects and inhibit non-radiative recombination, and in terms of spatial structure, it can promote orderly growth of grains and reduce defect generation. In terms of internal structure, it can improve the density and peeling resistance of the electron transport layer, perovskite layer and the interface between the two, thereby achieving a significant improvement in the stability of the perovskite battery and the photoelectric conversion efficiency. It should also be noted that the present invention simultaneously uses p-guanidinobenzonitrile hydrochloride and potassium cinnamate, two modifiers, which are reasonably matched to promote each other, and the two will not produce mutual inhibition, and have good synergy.

[0044] It should also be noted that the present invention simultaneously uses guanidine benzonitrile hydrochloride and potassium cinnamate to modify the electron transport layer and the perovskite layer respectively. Both of them contain benzene rings in their structures, which have large steric hindrance. They are filled between the grains of the electron transport layer and the perovskite layer to effectively block the invasion of water molecules, thereby preventing the perovskite material from reacting with water to deteriorate or decompose, effectively inhibiting the degradation of the perovskite material, and thus improving the stability and service life of the perovskite battery.

[0045] The present invention also provides a method for preparing the perovskite battery, which comprises the following steps:

[0046] S1, dissolving the first modifier in an organic solvent to obtain an electron transport layer precursor solution, and subjecting the electron transport layer precursor solution to a deposition process to obtain the electron transport layer;

[0047] S2. Preparing the perovskite light-absorbing layer on the surface of the electron transport layer prepared in step S1 to prepare the perovskite cell.

[0048] It is understandable that the preparation of the above-mentioned electron transport layer, buried interface modification layer and perovskite light absorption layer is only part of the process steps in the preparation of perovskite cells of the present invention, and may also include the preparation of other functional layers to prepare a complete perovskite cell device, and the above-mentioned other functional layers include but are not limited to a conductive substrate, a hole transport layer, a back electrode and some modification layers such as a passivation layer, which can be prepared by methods familiar to those skilled in the art. For example, in some embodiments, the method for preparing a perovskite solar cell also includes the following steps: cleaning the conductive substrate; preparing a hole transport layer; preparing a back electrode.

[0049] In one embodiment, in the step S1, the concentration of the first modifier in the electron transport layer precursor solution is 0.25-2.0 mg / mL.

[0050] Preferably, in one embodiment, in the step S1, the concentration of guanidine benzonitrile hydrochloride in the electron transport layer precursor solution is 0.25-2.0 mg / mL; in the step S1, the concentration of guanidine benzonitrile hydrochloride in the electron transport layer precursor solution can be any value of 0.25 mg / mL, 0.26 mg / mL, 0.3 mg / mL, 0.35 mg / mL, 0.5 mg / mL, 1.0 mg / mL, 1.5 mg / mL, and 2.0 mg / mL, including but not limited to the above values, as long as the concentration value is within the range, under the conditions of the above concentration range, guanidine benzonitrile hydrochloride can effectively modify and passivate the metal ions of the electron transport layer, can effectively passivate the oxygen vacancy defects in the electron transport layer, and can passivate a large number of uncoordinated Pb, Pb-I antisite defects and the like in the perovskite surface interface.

[0051] In one embodiment, in step S2, the perovskite light absorbing layer is prepared by depositing a perovskite precursor solution on the surface of the electron transport layer, wherein the concentration of the second modifier in the perovskite precursor solution is 5 to 10 mg / mL.

[0052] Preferably, in one embodiment, in the step S2, the perovskite light absorbing layer is prepared by depositing a perovskite precursor solution on the surface of the electron transport layer, wherein the concentration of potassium cinnamate in the perovskite precursor solution is 5-10 mg / mL.

[0053] It can be understood that the perovskite precursor solution in this embodiment includes a halide and a second modifier; when the second modifier is potassium cinnamate, the modification effect on the perovskite layer is better; the concentration of potassium cinnamate in the perovskite precursor solution can be any value of 5 mg / mL, 5.1 mg / mL, 5.5 mg / mL, 6 mg / mL, 6.8 mg / mL, 7 mg / mL, 8.5 mg / mL, and 10 mg / mL, including but not limited to the above values, as long as the concentration value is within the range, under the conditions of the above concentration range, potassium cinnamate can provide more coordination sites, can provide more bridging effects, enhance the interface stability of the electron transport layer and the perovskite layer, and improve the stability and photoelectric conversion efficiency of the perovskite battery.

[0054] In one embodiment, in step S1, the electron transport layer precursor solution further includes a metal oxide, and the mass fraction of the metal oxide in the solution is 3-5wt%. It should be noted that in the electron transport layer precursor solution, the mass fraction of the metal oxide can be any one of 3wt%, 3.1wt%, 3.4wt%, 3.5wt% and 5wt%, including but not limited to the above values, as long as the concentration value is within the range, under the conditions of the above concentration range, the first modifier, especially p-guanidinobenzonitrile hydrochloride, can have a better modification effect, the electron transport layer has fewer defects, and is conducive to electron transport.

[0055] In one embodiment, in the step S2, in the perovskite precursor solution, the concentration of the halide is 1 to 3 M. It should be noted that in the perovskite precursor solution, the concentration of the halide can be any one of 1M, 1.1M, 1.5M, 2M, 2.5M, and 3M; including but not limited to the above values, as long as the concentration value is within the range, under the conditions of the above concentration range, the modification effect of the second modifier, especially potassium cinnamate, can be better, the defects inside the perovskite layer can be reduced, and the interface energy barrier between the electron transport layer and the perovskite layer can be closer, which is more conducive to electron transport.

[0056] Optionally, in one embodiment, in step S1, the electron transport layer precursor solution further includes a metal oxide, and the mass fraction of the metal oxide in the solution is 3-5wt%; in step S2, in the perovskite precursor solution, the concentration of the halide is 1-3M. It should be noted that controlling the concentrations of the two precursor solutions simultaneously can make the synergistic modification of guanidinobenzonitrile hydrochloride and potassium cinnamate more effective, make the interface energy barrier between the electron transport layer and the perovskite layer closer, make the defects inside and at the interface of the electron transport layer and the perovskite layer less, and be more conducive to electron transport.

[0057] In one embodiment, in the step S1, the electron transport layer is prepared by spin coating, wherein during the spin coating process, the rotation speed is 2500 rpm to 5000 rpm, and the time is 25 s to 50 s.

[0058] In one embodiment, in the step S2, the perovskite light absorbing layer is prepared by spin coating, wherein the spin coating is firstly carried out at a rotation speed of 800 to 1500 rpm for 10 to 20 s, and then at a rotation speed of 2500 to 4000 rpm for 20 to 50 s.

[0059] In one embodiment, in the step S1, the first modifier and the metal oxide are dispersed in an organic solvent and stirred evenly to obtain the electron transport layer precursor solution, the electron transport layer precursor solution is transferred to the surface of the conductive glass, and annealed at 120 to 170° C. for 25 to 40 minutes to obtain the electron transport layer.

[0060] In one embodiment, the electron transport layer that has completed annealing is cleaned; the cleaning method includes ultraviolet ozone irradiation treatment or plasma plasma treatment, etc., to remove residues and impurities on the surface of the electron transport layer, thereby strengthening the contact and bonding between the electron transport layer and the perovskite light absorbing layer, which is beneficial to reducing the energy barrier between the interfaces and reducing the defects between the interfaces, and is more conducive to electron transport.

[0061] In one embodiment, in the step S2, the second modifier and the halide are dispersed in an organic solvent and stirred evenly to obtain the perovskite precursor solution, the perovskite precursor solution is transferred to the surface of the electron transport layer prepared in the step S1, and annealed at 100° C. for 10 to 20 minutes to obtain the perovskite light absorbing layer.

[0062] The present invention is further described below by means of specific embodiments:

[0063] The raw materials used in the embodiments of the present invention are all commercially available, and the present invention does not impose any restrictions on the sources of the raw materials.

[0064] Example 1

[0065] The perovskite cell in Example 1 includes: a FTO glass substrate, an electron transport layer, a perovskite light absorption layer, a passivation layer, a hole transport layer and a metal back electrode.

[0066] The method for preparing the perovskite battery in Example 1 comprises the following steps:

[0067] S1. The FTO glass was cleaned by ultrasonic for 15 min in anionic surfactant solution, deionized water, ethanol and isopropanol respectively, and dried to obtain a FTO glass substrate.

[0068] S2, dilute 15wt% of commercial SnO2 colloidal dispersion and deionized water in a volume ratio of 1:3, ultrasonically treat for 10min, obtain SnO2 solution, then add an appropriate amount of guanidine benzonitrile hydrochloride, and prepare an electron transport layer precursor solution (CG-SnO2), wherein the concentration of guanidine benzonitrile hydrochloride is 1.5mg / mL. The FTO glass substrate prepared in step S1 is treated with ozone for 20min, and then the electron transport layer is prepared by static spin coating in an air atmosphere, the spin coating speed is 3000rpm, the time is 30s, and the amount of the electron transport layer precursor solution is 100μL. After annealing at 150°C for 30min, an electron transport layer is obtained.

[0069] S3, accurately weigh 19.5 mg CsI, 146.8 mg FAI, 691.5 mg PbI2, dissolve them in 1 mL anhydrous organic solvent, and add 6 mg potassium cinnamate (PCA), wherein the anhydrous organic solvent includes DMF and DMSO in a volume ratio of 4:1; shake the vortex vibrating screen for 2 hours to obtain a perovskite precursor solution, wherein the components of the precursor solution are Cs 0.05 FA 0.95 PbI3, with a concentration of 1.5M; the electron transport layer prepared in step S2 was treated with ozone for 20 minutes, and 70 μL of the perovskite precursor solution was spin-coated in a nitrogen atmosphere, first at a rotation speed of 1000 rpm for 10 seconds, and then at a rotation speed of 3000 rpm for 30 seconds, and 150 μL of anhydrous chlorobenzene was quickly added dropwise at 15 seconds in the second process, and annealed at 100°C for 10 minutes after the spin coating to obtain the perovskite light absorbing layer.

[0070] S4. Accurately weigh 15 mg of phenethylammonium iodide (PEAI), dissolve it in 3 mL of anhydrous IPA, dissolve and mix the solution, and spin-coat 100 μL of the solution onto the surface of the perovskite light-absorbing layer prepared in step S3 under a nitrogen atmosphere. The spin-coating speed is 5000 rpm for 30 s. No annealing is required to obtain a passivation layer.

[0071] S5, accurately weigh 90 mg Spiro-OMeTAD, add 44 μL bis(trifluoromethane)sulfonyl imide lithium salt (LiTFSI) stock solution (260 mg Li-TFSI dissolved in 1 ml anhydrous acetonitrile), 37 μL tBP (4-tert-butylpyridine) and 1 mL anhydrous chlorobenzene, ultrasonically treat for 5 min, take 60 μL of the solution and spin-coat it on the surface of the passivation layer prepared in step S4 under a nitrogen atmosphere, the spin coating speed is 2000 rpm, the time is 30 s, no annealing is required, and a hole transport layer is obtained;

[0072] S6. A 100 nm thick Au electrode is evaporated on the surface of the device treated in step S5 to obtain a perovskite cell.

[0073] Example 2

[0074] The perovskite cell in Example 2 includes: a FTO glass substrate, an electron transport layer, a perovskite light absorption layer, a passivation layer, a hole transport layer and a metal back electrode.

[0075] Example 2 is based on Example 1, except that in Example 2, the components and proportions of the perovskite precursor solution in step S3 are different, as follows:

[0076] 19.5 mg CsI, 15.9 mg RbI, 8.4 mg MABr, 219.5 mg FAI, 656.9 mg PbI2 and 27.5 mg PbBr2 were accurately weighed and dissolved in 1 mL of anhydrous organic solvent, and 6 mg potassium cinnamate (PCA) was added. The anhydrous organic solvent included DMF and DMSO in a volume ratio of 4:1. The vortex vibrating screen was shaken for 2 h to obtain a perovskite precursor solution. The components of the precursor solution were Rb 0.05 Cs 0.05 MA 0.05 FA 0.85 Pb(I 0.95 Br 0.05 )3, the concentration is 1.5M.

[0077] Example 3

[0078] Example 3 is based on Example 1, with the difference that: in Example 3, in step S2, the concentration of guanidine benzonitrile hydrochloride in the electron transport layer precursor solution (CG-SnO2) is changed to 0.25 mg / mL; at the same time, in step S3, the concentration of potassium cinnamate in the perovskite precursor solution is changed to 5 mg / mL.

[0079] Example 4

[0080] Example 4 is based on Example 1, with the difference that: in Example 4, in step S2, the concentration of guanidine benzonitrile hydrochloride in the electron transport layer precursor solution (CG-SnO2) is changed to 2 mg / mL; at the same time, in step S3, the concentration of potassium cinnamate in the perovskite precursor solution is changed to 10 mg / mL.

[0081] Example 5

[0082] Example 5 is based on Example 2, with the difference that: in Example 5, in step S2, the concentration of guanidine benzonitrile hydrochloride in the electron transport layer precursor solution (CG-SnO2) is 0.25 mg / mL; at the same time, in step S3, the concentration of potassium cinnamate in the perovskite precursor solution is changed to 5 mg / mL.

[0083] Example 6

[0084] Example 6 is based on Example 2, with the difference that: in Example 6, in step S2, the concentration of guanidine benzonitrile hydrochloride in the electron transport layer precursor solution (CG-SnO2) is 2 mg / mL; at the same time, in step S3, the concentration of potassium cinnamate in the perovskite precursor solution is changed to 10 mg / mL.

[0085] Example 7

[0086] Example 7 is based on Example 1, with the difference that: in Example 7, in step S2, p-guanidinobenzonitrile hydrochloride is not added to the electron transport layer precursor solution, and in step S3, the concentration of potassium cinnamate in the perovskite precursor solution remains unchanged.

[0087] Comparative Example 1

[0088] Comparative Example 1 is based on Example 1, except that the perovskite cell in Comparative Example 1 is not modified by using guanidinobenzonitrile hydrochloride and potassium cinnamate during the preparation process.

[0089] Comparative Example 2

[0090] Comparative Example 2 is based on Example 1, except that the perovskite cell in Comparative Example 2 is not modified by using guanidinobenzonitrile hydrochloride and potassium cinnamate during the preparation process.

[0091] Comparative Example 3

[0092] Comparative Example 3 is based on Example 1, except that: in Comparative Example 3, in step S3, potassium cinnamate is not added to the perovskite precursor solution, and in step S2, the concentration of guanidine benzonitrile hydrochloride in the electron transport layer precursor solution remains unchanged.

[0093] Comparative Example 4

[0094] Comparative Example 4 is based on Example 1, except that: in Example 7, in step S2, the concentration of guanidine benzonitrile hydrochloride in the electron transport layer precursor solution is changed to 3 mg / mL, and in step S3, the concentration of potassium cinnamate in the perovskite precursor solution remains unchanged.

[0095] Comparative Example 5

[0096] Comparative Example 5 is based on Example 1, except that: in Comparative Example 5, in step S3, the concentration of potassium cinnamate in the perovskite precursor solution is changed to 13 mg / mL, and in step S2, the concentration of guanidine benzonitrile hydrochloride in the electron transport layer precursor solution remains unchanged.

[0097] Performance Testing

[0098] (1) The current density (J)-voltage (V) curves of the perovskite batteries prepared in Examples 1-2 and Comparative Examples 1-2 were measured respectively; the current density (J)-voltage (V) curves of the perovskite batteries prepared in Examples 1-2 and Comparative Examples 1-2 after being stored for 7 days at a temperature of 25° C. and a humidity of 40-50% were measured respectively. The measurement results are shown in FIG. Figures 1 to 4 ;

[0099] (2) The Voc open circuit voltage (V), Jsc short circuit current density (mA / cm2) and the Voc open circuit voltage (V) of the perovskite cells prepared in Examples 1 to 7 and Comparative Examples 1 to 5 were measured respectively. 2 ), FF filling factor (mA / cm 2 ) and PCE photoelectric conversion efficiency (%), the measurement results are shown in Table 1.

[0100] Table 1

[0101]

[0102] right Figures 1 to 4 To perform the analysis:

[0103] Figure 1 The photoelectric conversion efficiency of Example 1 is significantly higher than that of Comparative Example 1.

[0104] Figure 2 The curve on the left is a comparison of the JV curves of Comparative Example 1 before and after storage for 7 days. The efficiency of Comparative Example 1 is significantly reduced after storage for 7 days in a medium humidity environment. Figure 2 The curve in the middle right figure is Example 1. There is no obvious change in efficiency before and after 7 days of storage. Therefore, the stability of Example 1 is obviously better.

[0105] Figure 3 The photoelectric conversion efficiency of Example 2 is significantly higher than that of Comparative Example 2.

[0106] Figure 4 The curve on the left is a comparison of the JV curves of Comparative Example 2 before and after storage for 7 days. The efficiency of Comparative Example 2 is significantly reduced after storage for 7 days in a medium humidity environment. Figure 4 The curve in the middle right figure is Example 2. There is no obvious change in efficiency before and after 7 days of storage. Therefore, the stability of Example 2 is obviously better.

[0107] By analyzing Table 1, the performance of the embodiments is higher than that of the comparative examples in terms of open circuit voltage, short circuit current density, fill factor and photoelectric conversion efficiency.

[0108] Therefore, the present invention simultaneously uses p-guanidinobenzonitrile hydrochloride and potassium cinnamate to modify the electron transport layer and the perovskite layer respectively, which can improve the stability and photoelectric conversion efficiency of the perovskite battery.

[0109] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A perovskite battery, characterized in that: The perovskite cell comprises an electron transport layer and a perovskite light absorbing layer, the electron transport layer comprises a first modifier, and the functional groups in the first modifier comprise at least two of guanidine, phenyl and cyano.

2. The perovskite battery according to claim 1, characterized in that In the electron transport layer, the first modifier includes p-guanidinobenzonitrile hydrochloride.

3. The perovskite battery according to claim 1, characterized in that The electron transport layer further comprises a metal oxide, wherein the metal oxide comprises at least one of SnO2, TiO2, ZnO, BaSnO3, and CeO2; And / or, the perovskite light-absorbing layer includes a halide, and the halide includes at least one of CsI, CsBr, CsCl, KI, KBr, KCl, RbI, RbBr, RbCl, MAI, MABr, MACl, FABr, and FACl.

4. The perovskite battery according to claim 1, characterized in that The perovskite light-absorbing layer includes a second modifier, and the functional groups in the second modifier include at least two of a carboxyl group, a phenyl group, and a potassium ion.

5. The perovskite battery according to claim 4, characterized in that: The second modifier includes a carboxyl potassium salt, and the carboxyl potassium salt includes at least one of potassium cinnamate, potassium oxalate, and potassium pyromellitic acid.

6. A method for preparing a perovskite battery according to any one of claims 1 to 5, characterized in that: The method for preparing the perovskite battery comprises the following steps: S1, dissolving the first modifier in an organic solvent to obtain an electron transport layer precursor solution, and subjecting the electron transport layer precursor solution to a deposition process to obtain the electron transport layer; S2. Preparing the perovskite light-absorbing layer on the surface of the electron transport layer prepared in step S1 to prepare the perovskite cell.

7. The method for preparing a perovskite battery according to claim 6, characterized in that: In the step S1, the concentration of the first modifier in the electron transport layer precursor solution is 0.25 to 2.0 mg / mL; And / or, in step S2, the perovskite light absorbing layer is prepared by depositing a perovskite precursor solution on the surface of the electron transport layer, Wherein, in the perovskite precursor solution, the concentration of the second modifier is 5 to 10 mg / mL.

8. The method for preparing a perovskite battery according to claim 7, characterized in that: In the step S1, the electron transport layer precursor solution further includes a metal oxide, and the mass fraction of the metal oxide in the solution is 3-5wt%; And / or, in the step S2, the concentration of the halide in the perovskite precursor solution is 1-3M.

9. The method for preparing a perovskite battery according to claim 6, characterized in that: In the step S1, the electron transport layer is prepared by spin coating, wherein the rotation speed is 2500 rpm to 5000 rpm and the time is 25 s to 50 s during the spin coating process; And / or, in the step S2, the perovskite light absorbing layer is prepared by spin coating, wherein the spin coating is firstly carried out at a rotation speed of 800 to 1500 rpm for 10 to 20 s, and then at a rotation speed of 2500 to 4000 rpm for 20 to 50 s.

10. The method for preparing a perovskite battery according to claim 6, characterized in that: In the step S1, the first modifier and the metal oxide are dispersed in an organic solvent and stirred to obtain the electron transport layer precursor solution, the electron transport layer precursor solution is transferred to the surface of the conductive glass, and annealed at 120 to 170° C. for 25 to 40 minutes to obtain the electron transport layer; And / or, in the step S2, the second modifier and the halide are dispersed in an organic solvent and stirred evenly to obtain the perovskite precursor solution, the perovskite precursor solution is transferred to the surface of the electron transport layer obtained in the step S1, and annealed at 100° C. for 10 to 20 minutes to obtain the perovskite light absorbing layer.

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