Perylene diimide compound, perovskite battery and preparation method thereof

Abstract

The invention belongs to the technical field of photovoltaic cells, and discloses a perylene diimide compound, a perovskite cell and a preparation method of the perylene diimide compound, and the chemical general formula of the perylene diimide compound is shown as a formula (i). According to the perylene diimide compound provided by the invention, an R1 group is an aromatic group containing amino, and ammonium ions and halogen ions can be formed after the R1 group is protonized. The perylene diimide compound interface passivation layer is introduced into the perovskite solar cell, so that the interface recombination of perovskite and an electron transport layer can be greatly reduced, the open-circuit voltage loss is remarkably reduced, and the device efficiency is remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application generally relates to the technical field of photovoltaic cells. More particularly, the present application relates to a perylene diimide compound, a perovskite cell and a preparation method thereof. BACKGROUND

[0002] The perovskite solar cell material has the advantages of high efficiency, low cost, simple manufacturing process, wide spectral absorption range, etc., and can maintain photoelectric conversion rate even under weak light conditions.

[0003] At present, the conversion efficiency (PCEs) of perovskite cells is low, and a large part of non-radiative recombination loss is derived from the perovskite / electron transport layer interface. At present, most of the electron transport layer materials use fullerene compounds, among which C 60 and [6,6]-phenyl-C61-butyric acid isomethyl ester (PCBM) prepared by solution method are mainly used. However, fullerene materials are expensive and are not conducive to industrialized low-cost production.

[0004] Perylene diimide compounds are widely studied and are one of the important materials in the field of organic electronics due to their excellent chemical and photophysical stability, electron acceptor performance and easy derivatization, and the price is relatively low compared with fullerene materials. In the reported literature (J. Mater. Chem. A, 2022, 10, 11046), perylene diimide compounds are used as electron transport layers in perovskite solar cells, achieving a conversion efficiency of 16.8%, which is very close to the efficiency of the battery based on the commonly used PCBM as the electron transport layer (17.2%) under the same conditions.

[0005] However, based on perylene diimide compounds, the transport performance of perylene diimide is mainly improved by changing the modification group, but there is no research on the non-radiative recombination loss of the perovskite / electron transport layer interface (i.e. the electron transport layer based on perylene diimide compounds). In order to improve the efficiency of the battery, it is crucial to inhibit this part of non-radiative recombination. In addition, the LUMO level of perylene diimide compounds is in the range of -3.6 to -3.8 eV (NATURE COMMUNICATIONS (2020) 11:2726), which does not match the energy level of commonly used perovskite materials.

[0006] Therefore, there is an urgent need for improved technical solutions for perylene diimide compounds to solve the problem of mismatching with the energy level of commonly used perovskite materials. SUMMARY

[0007] To solve at least one or more technical problems as mentioned above, provided in embodiments of the present application is a perylene diimide compound, a chemical formula of which is shown as formula (i):

[0008]

[0009] wherein R1 is selected from 3-aminophenyl, 4-aminophenyl;

[0010] wherein R2 is selected from alkyl with a chain length of C1-C12, C5-C12 aromatic group;

[0011] wherein X is selected from chlorine, bromine, iodine.

[0012] According to one embodiment of the present application, a chemical formula of the perylene diimide compound is shown as formula (ii):

[0013]

[0014] According to one embodiment of the present application, X in the perylene diimide compound is iodine.

[0015] According to another aspect of the present application, the aforementioned perylene diimide compound is applied as an interface passivation agent of a perovskite cell.

[0016] According to another aspect of the present application, a perovskite cell is provided, which comprises a first electrode layer, a hole transport layer, a perovskite light-absorbing layer, an interface passivation layer, an electron transport layer and a second electrode layer stacked in sequence, and the interface passivation layer comprises the aforementioned perylene diimide compound.

[0017] According to one embodiment of the present application, the first electrode layer comprises a metal electrode or a transparent oxide electrode; and the second electrode layer comprises a metal electrode or a transparent oxide electrode.

[0018] According to one embodiment of the present application, the hole transport layer comprises one or more of NiO x , PTAA, 2-PACz, Me-4PACz.

[0019] According to one embodiment of the present application, the electron transport layer comprises the aforementioned perylene diimide compound.

[0020] According to one embodiment of the present application, a structure formula of the perovskite in the perovskite light-absorbing layer is ABX3, wherein: A is selected from one or more of CH3NH3 + (MA + ), CH2(NH3)2 (FA + ), Cs + ; and B is selected from Pb 2+ , Sn2+ One or a mixture of two of them; X is selected from I - ,Br - Cl - A mixture of one or more of them.

[0021] According to another aspect of the present invention, a method for preparing a perovskite solar cell is provided, comprising: preparing a first electrode layer; forming a hole transport layer on the first electrode layer; forming a perovskite light-absorbing layer on the hole transport layer; forming an interface passivation layer and an electron transport layer on the perovskite light-absorbing layer, the interface passivation layer and the electron transport layer comprising the aforementioned perylene diimide compound; and forming a second electrode layer on the electron transport layer.

[0022] According to another aspect of the present invention, a method for preparing a perovskite solar cell is provided, comprising: preparing a first electrode layer; forming a hole transport layer on the first electrode layer; forming a perovskite light-absorbing layer on the hole transport layer; forming an interface passivation layer on the perovskite light-absorbing layer, the interface passivation layer comprising the aforementioned perylene diimide compound; forming an electron transport layer on the interface passivation layer; and forming a second electrode layer on the electron transport layer.

[0023] According to another aspect of the present invention, a method for preparing a perovskite solar cell is provided, comprising: cleaning ITO conductive glass to obtain a first electrode layer; depositing nickel oxide on the first electrode layer to form a hole transport layer; depositing perovskite on the hole transport layer to form a perovskite light-absorbing layer; dissolving the aforementioned perylene diimide compound in a polar solvent and spin-coating it onto the surface of the perovskite light-absorbing layer to form an interface passivation layer and an electron transport layer; and depositing a metal electrode on the electron transport layer to form a second electrode layer. Preferably, the concentration of the perylene diimide compound is 5–20 mg / mL. Preferably, the thickness of the interface passivation layer and the electron transport layer is 10–45 nm.

[0024] According to another aspect of the present invention, a method for preparing a perovskite solar cell is provided, comprising: cleaning an ITO conductive glass to obtain a first electrode layer; depositing nickel oxide on the first electrode layer to form a hole transport layer; depositing perovskite on the hole transport layer to form a perovskite light-absorbing layer; dissolving the aforementioned perylene diimide compound in a polar solvent at a concentration of 0.1–5 mg / mL and spin-coating it onto the surface of the perovskite light-absorbing layer to form an interface passivation layer; preparing an electron transport layer on the interface passivation layer; and depositing a metal electrode on the electron transport layer to form a second electrode layer.

[0025] The R1 group of the perylene diimide compound provided above is an aromatic group containing an amino group, which forms an ammonium ion and a halogen ion after protonation. By introducing the perylene diimide compound interface passivation layer in the perovskite solar cell, the interface recombination of perovskite and electron transport layer can be greatly reduced, thereby significantly reducing the open-circuit voltage loss and significantly improving the device efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0026] The above and other objects, features and advantages of the present application exemplary embodiments will be more apparent from the following detailed description read in conjunction with the accompanying drawings, in which several embodiments of the present application are shown by way of example, and wherein the same or corresponding elements refer to the same or corresponding parts wherein:

[0027] Figure 1 A structural schematic diagram of a perovskite cell containing an interface passivation layer is shown.

[0028] Figure 2 A step schematic diagram of a preparation method of a perovskite cell is shown.

[0029] Figure 3 A step schematic diagram of another preparation method of a perovskite cell is shown.

[0030] Figure 4 A PLQY value distribution diagram of a perovskite thin film, a perovskite / interface passivation layer / C 60 thin film is shown. 60 DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of, rather than all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0032] It should be understood that the terms "include" and "contain" used in the specification and claims of the present application indicate the presence of the described features, whole, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, whole, steps, operations, elements, components and / or sets thereof.

[0033] ​It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. As used in this specification and the appended claims, the singular forms "a," "an" and "the" include plural referents unless the context clearly dictates otherwise. It is further to be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items, and that the term "at least one of" as used herein means one or more.

[0034] As used in this specification and claims, the terms "if' and "when" can each be interpreted to mean "upon determination" or "in response to a determination" or "upon detection" or "in response to a detection" depending on the context. Similarly, the phrase "if determined" or "if detected [the described condition or event]" can be interpreted to mean "upon determination" or "in response to a determination" or "upon detection" or "in response to a detection" depending on the context.

[0035] The specific embodiments of the present application will now be described in detail with reference to the following figures.

[0036] In the embodiments of the present application, an improved direction of changing the transport properties of perylene diimides by changing the modification group is provided, and specifically, a perylene diimide compound with an aromatic group containing an amino group as the main modification group is provided, which can be represented by the general formula (i):

[0037]

[0038] wherein R1 is selected from 3-aminophenyl and 4-aminophenyl; R2 is selected from alkyl with a chain length of C1-C12 and C5-C12 aromatic group; and X is selected from chlorine, bromine and iodine. The R1 group will form an ammonium ion and a halogen ion after protonation, which can passivate the interface defects and prevent interface recombination. The halogen can passivate the dangling bonds on the surface of the perovskite.

[0039] Preferably, the chemical formula of the perylene diimide compound is shown in formula (ii):

[0040]

[0041]

[0042] In an embodiment of the present application, the use of the aforementioned perylene diimide compound as an interface passivation agent for perovskite solar cells is also provided. The interface passivation agent can form an interface passivation layer through a spin coating process or the like, which is attached to the surface of the perovskite light-absorbing layer to prevent interface recombination.

[0043] Figure 1A schematic diagram of a perovskite solar cell including an interface passivation layer is shown.

[0044] like Figure 1 As shown, in one embodiment of the present invention, a perovskite solar cell is provided, comprising a first electrode layer 101, a hole transport layer 102, a perovskite light-absorbing layer 103, an interface passivation layer 104, an electron transport layer 105, and a second electrode layer 106 stacked sequentially. The interface passivation layer 104 comprises the aforementioned perylene diimide compound, exhibiting good photoelectric conversion efficiency. The perovskite in the perovskite light-absorbing layer 103 comprises halogen. Other layers can be prepared using existing or future invented materials and methods, and are not limited in this embodiment of the present invention.

[0045] According to one embodiment of the present invention, the first electrode layer of the perovskite solar cell includes a metal electrode or a transparent oxide electrode, and the second electrode layer includes a metal electrode or a transparent oxide electrode, which can be arbitrarily combined.

[0046] According to one embodiment of the present invention, the hole transport layer comprises nickel oxide (NiO). x One or a combination of several of the following: poly(4-phenyl)(2,4,6-trimethylphenyl)amine (PTAA), [2-(9H-carbazole-9-yl)ethyl]phosphonic acid (2-PACz), and [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (Me-4PACz).

[0047] According to one embodiment of the present invention, the electron transport layer comprises the aforementioned perylene diimide compound, that is, both the electron transport layer and the interface passivation layer comprise the aforementioned perylene diimide compound, or the electron transport layer and the interface passivation layer are prepared using the same material comprising the aforementioned perylene diimide compound.

[0048] According to one embodiment of the present invention, the perovskite structure in the perovskite light-absorbing layer is ABX3, wherein: A is selected from CH3NH3. + (MA + ), CH2(NH3)2(FA + ), Cs + A mixture of one or more of the following; B is selected from Pb. 2+ Sn 2+ One or a mixture of two of them; X is selected from I - ,Br - Cl - A mixture of one or more of them.

[0049] Figure 2 A schematic diagram of the steps involved in the fabrication of a perovskite solar cell is shown.

[0050] like Figure 2As shown, the preparation method 200 of perovskite cell includes: a first step S201 of preparing a first electrode layer: cleaning a conductive substrate, taking ITO conductive glass as a device substrate and as a first electrode layer at the same time; a second step S202 of forming a hole transport layer on the first electrode layer: preparing nickel oxide on the ITO conductive glass as a hole transport layer, which can be prepared by a solution method or a magnetron sputtering method; a third step S203 of forming a perovskite light-absorbing layer on the hole transport layer: preparing a perovskite light-absorbing layer on the hole transport layer, which is prepared by a solution method; a fourth step S204 of forming an interface passivation layer and an electron transport layer on the perovskite light-absorbing layer: dissolving an interface passivation agent (the aforementioned perylene diimide compound) in a polar solvent such as isopropyl alcohol to form a solution with a concentration of 5-20 mg / mL, and then spin coating it on the surface of the perovskite light-absorbing layer; and a fifth step S205 of forming a second electrode layer on the electron transport layer: depositing a metal electrode on the electron transport layer by a vacuum evaporation method. In the above preparation method, the electron transport layer and the interface passivation layer are prepared by using the same material. Preferably, the concentration of the perylene diimide compound in the solution is 5-20 mg / mL, including 5 mg / mL, 6 mg / mL, 7 mg / mL, 8 mg / mL, 9 mg / mL, 10 mg / mL, 11 mg / mL, 12 mg / mL, 13 mg / mL, 14 mg / mL, 15 mg / mL, 16 mg / mL, 17 mg / mL, 18 mg / mL, 19 mg / mL, 20 mg / mL, preferably, the thickness of the interface passivation layer and the electron transport layer is 10-45 nm, and more preferably, the thickness is 15-35 nm. For example: 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm.

[0051] Figure 3 A step schematic diagram of another preparation method of perovskite cell is shown.

[0052] As Figure 3As shown, the preparation method 300 of the perovskite cell comprises: step one S301, preparing a first electrode layer: cleaning a conductive substrate, taking ITO conductive glass as a device substrate and as a first electrode layer; step two S302, forming a hole transport layer on the first electrode layer: preparing nickel oxide on the ITO conductive glass as a hole transport layer, which can be prepared by a solution method or a magnetron sputtering method; step three S303, forming a perovskite light-absorbing layer on the hole transport layer: preparing a perovskite light-absorbing layer on the hole transport layer, which can be prepared by a solution method; step four S304, forming an interface passivation layer on the perovskite light-absorbing layer: dissolving an interface passivation agent (the aforementioned perylene diimide compound) in a polar solvent such as isopropanol, etc., to form a solution with a concentration of 0.1-5 mg / mL, including 0.1 mg / mL, 0.5 mg / mL, 1 mg / mL, 1.5 mg / mL, 2 mg / mL, 2.5 mg / mL, 3 mg / mL, 3.5 mg / mL, 4 mg / mL, 4.5 mg / mL, 5 mg / mL, and then spin coating it on the surface of the perovskite light-absorbing layer; step five S305, forming an electron transport layer on the interface passivation layer: preparing an electron transport layer on the perovskite light-absorbing layer by a vacuum evaporation method; step six S306, forming a second electrode layer on the electron transport layer: depositing a metal electrode on the surface of the electron transport layer by a vacuum evaporation method. In the above preparation method, the electron transport layer and the interface passivation layer are prepared by selecting different materials.

[0053] Through the above effects, the introduction of the perylene diimide compound interface passivation layer in the perovskite cell can greatly reduce the interface recombination of the perovskite and the electron transport layer, thereby significantly reducing the open-circuit voltage loss and significantly improving the device efficiency.

[0054] Example 1.

[0055] The perylene diimide compound is prepared as shown below:

[0056] The raw materials include compound 1 and compound 2, both of which are commercially available compounds, wherein:

[0057] Compound 1 is 3,4,9,10-perylenetetracarboxylic dianhydride (CAS: 128-69-8).

[0058] Compound 2 is 3-aminopentane (CAS: 616-24-0).

[0059]

[0060] The steps include:

[0061] i) Take 10 mmol of compound 1 and 20 mmol of compound 2 into a 200 mL three-necked flask, add 100 mL of pyridine as a reaction solvent, take zinc acetate as a catalyst, reflux at room temperature for 8 hours, purify to obtain 5.2 mmol of compound 3, and the yield is 52%.

[0062] ii) Take 2 mmol of compound 3, 0.06 mmol of methoxy (cyclooctadiene) iridium dimer, 0.24 mol of tris (pentafluorophenyl) and 16 mmol of bis (pinacol) diboron into a reaction flask, replace the water and oxygen in the reaction flask by nitrogen gas for 3 times, inject 40 mL of anhydrous 1, 4-dioxane as a solvent under nitrogen protection. React at 110 degrees Celsius for 72 hours. After the reaction is completed, remove the solvent by a rotary evaporator, purify to obtain 1.4 mmol of compound 4, and the yield is 70%.

[0063] iii) Take 0.1 mmol of compound 4, 0.4 mmol of 4-bromoaniline, 2 mmol of potassium carbonate, 0.004 mmol of tris (dibenzylideneacetone) dipalladium and 0.01 mmol of 2-biscyclohexylphosphine-2', 6'-dimethoxy-1, 1'-biphenyl into a 100 mL reaction flask, replace the oxygen in the reaction flask by nitrogen gas for 3 times, add 50 mL of toluene and 5 mL of deionized water, and react at 100 degrees Celsius for 72 hours. After the reaction is completed, separate the organic phase, dry the organic phase with sodium sulfate. Remove the solvent by a rotary evaporator, purify to obtain 0.012 mmol of compound 5.

[0064] vi) Take 0.012 mmol of compound 5, add 50 mL of deionized water, and add 0.6 mmol of hydroiodic acid (as a 57% mass fraction of hydroiodic acid aqueous solution). Slowly drop during the dropping process to prevent the reaction from being too violent, react at room temperature for 6 hours, and separate to obtain 0.011 mmol of compound 6, which is a perylene diimide compound.

[0065] Example 2.

[0066] Prepare a perovskite solar cell containing a perylene diimide compound in the interface passivation layer, as follows:

[0067] Step 1), clean the electrode-coated conductive substrate: after ultrasonic cleaning of ITO conductive glass with glass cleaning solution, deionized water, ethanol, isopropanol, drying at 200 degrees, blowing dry with nitrogen flow, and ultraviolet ozone cleaning for 15 min, obtain clean ITO conductive glass as a substrate.

[0068] Step 2), prepare a hole transport layer: prepare NiO x Take 10 mg / mLNiO as a hole transport layerx The nanoparticle aqueous solution was mixed with isopropanol at a volume ratio of 3:1, and then dropped onto the surface of an ITO conductive glass substrate. A spin coater was used for spin coating at a speed of 3000 rpm for 30 s. The sample was quickly transferred to a nitrogen atmosphere. A 0.03 mg / mL Me-4PACz ethanol solution was spin coated on the surface of the NiO x

[0069] Step 3), preparation of a perovskite light-absorbing layer: a perovskite light-absorbing layer was prepared on the hole transport layer formed in step 2). CsI, FAI, PbI2, and PbBr2 were mixed at a molar ratio of 2:8:4:6 to form a solution with a concentration of 1.2 M, and DMF and DMSO were used as solvents at a volume ratio of 4:1. The solution was stirred for 2 hours to ensure complete dissolution, and a clear solution was obtained as a perovskite precursor solution containing FA 0.8 Cs 0.2 Pb(I 0.6 Br 0.4 )3. 100 μl of the perovskite precursor solution was dropped onto the surface of the nickel oxide coated with the self-assembled monolayer Me-4PACz (hole transport layer) at a speed of 4000 rpm for 32 s, and 100 ul of chlorobenzene was added as an anti-solvent at the 24th second. Annealing was performed at a temperature of 100°C for 10 minutes to form a perovskite light-absorbing layer.

[0070] Step 4), preparation of an interface passivation layer: the "compound 6" molecule prepared in Example 1 was dissolved in isopropanol at a concentration of 0.5 mg / mL, and spin coated on the surface of the perovskite light-absorbing layer at a speed of 2000 rpm for 20 s. Annealing was then performed at a temperature of 100°C for 10 minutes to form an interface passivation layer.

[0071] Step 5), preparation of an electron transport layer: an electron transport layer was prepared on the interface passivation layer. Fullerene (C 60 ) and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) were deposited by vacuum evaporation at a rate of about 0.1 nm / s to form an electron transport layer.

[0072] Step 6), deposition of a metal electrode on the electron transport layer by vacuum evaporation at a thickness of 100 nm and a rate of about 0.2 nm / s to form a metal electrode.

[0073] ​Thus, a perovskite solar cell containing compound 6 in the interface passivation layer is obtained.

[0074] Example 3.

[0075] A perovskite solar cell containing a perylene diimide compound in the interface passivation layer is prepared as follows:

[0076] The preparation process is basically the same as that of Example 2, except that the concentration of the "compound 6" molecule in step 4) is 0.1 mg / mL.

[0077] Example 4.

[0078] A perovskite solar cell containing a perylene diimide compound in the interface passivation layer is prepared as follows:

[0079] The preparation process is basically the same as that of Example 2, except that the concentration of the "compound 6" molecule in step 4) is 1 mg / mL.

[0080] Example 5.

[0081] A perovskite solar cell containing a perylene diimide compound in the interface passivation layer is prepared as follows:

[0082] The preparation process is basically the same as that of Example 2, except that the concentration of the "compound 6" molecule in step 4) is 5 mg / mL.

[0083] Example 6.

[0084] A perovskite solar cell containing a perylene diimide compound in the interface passivation layer and the electron transport layer is prepared as follows:

[0085] Step a, cleaning the electrode-coated conductive substrate: the ITO conductive glass is ultrasonically cleaned with glass cleaning solution, deionized water, ethanol, isopropanol, dried at 200 degrees Celsius, blown dry with nitrogen flow, and then ultraviolet ozone cleaned for 15 minutes to obtain clean ITO conductive glass as the device substrate.

[0086] Step b, preparing NiO x as a hole transport layer: 10 mg / mL NiO xThe nanoparticle aqueous solution was mixed with isopropanol at a volume ratio of 3:1, and was added dropwise to the upper surface of an ITO conductive glass substrate, and spin coating was performed using a spin coater at a rotation speed of 3000 rpm for 30 s. The spin-coated ITO conductive glass substrate was quickly transferred to a nitrogen atmosphere, and an ethanol solution of 0.03 mg / mL Me-4PACz was spin-coated on the surface of the NiOx layer using a spin coater at a rotation speed of 3000 rpm for 30 s. The spin-coated ITO conductive glass substrate was placed on a heating stage for annealing at a temperature of 100°C for 10 min, thereby forming a hole transport layer.

[0087] Step c: A perovskite light-absorbing layer was prepared on the hole transport layer formed in step b. CsI, FAI, PbI2, and PbBr2 were mixed at a molar ratio of 2:8:4:6 to form a solution with a concentration of 1.2 M, and a solvent of DMF and DMSO at a volume ratio of 4:1. The solution was stirred for 2 h to ensure complete dissolution, and a clear solution of a perovskite precursor solution containing FA 0.8 Cs 0.2 Pb(I 0.6 Br 0.4 )3) was obtained by filtration. 100 μl of the perovskite precursor solution was added dropwise to the surface of the hole transport layer, and spin coating was performed using a spin coater at a rotation speed of 4000 rpm for 32 s. At the 24th second, 100 ul of chlorobenzene was added as an anti-solvent. Annealing was performed at a temperature of 100°C for 10 min, thereby forming a perovskite light-absorbing layer.

[0088] Step d: An interface passivation layer and an electron transport layer were prepared. The “compound 6” molecule prepared in Example 1 was dissolved in isopropanol to form a solution with a concentration of 20 mg / mL, which was spin-coated on the surface of the perovskite light-absorbing layer formed in the third step using a spin coater at a rotation speed of 2000 rpm for 20 s. Annealing was then performed at a temperature of 100°C for 10 min, thereby forming an interface passivation layer and an electron transport layer with a thickness of 25 nm.

[0089] Step e: A metal electrode was deposited on the electron transport layer by vacuum evaporation at a thickness of 100 nm, and at an evaporation rate of about 0.2 nm / s, thereby forming a metal electrode.

[0090] Thus, a perovskite solar cell containing a perylene diimide compound in an interface passivation layer and an electron transport layer was obtained.

[0091] Example 7.

[0092] A perovskite solar cell containing a perylene diimide compound in an interface passivation layer and an electron transport layer was prepared as follows:

[0093] The preparation process is basically the same as that of Example 6, except that the thickness of the interface passivation layer and the electron transport layer based on the "compound 6" molecule in step d is 15 nm.

[0094] Example 8.

[0095] A perovskite solar cell containing a perylene diimide compound in the interface passivation layer and the electron transport layer is prepared as follows:

[0096] The preparation process is basically the same as that of Example 6, except that the thickness of the interface passivation layer and the electron transport layer based on the "compound 6" molecule in step d is 35 nm.

[0097] Example 9.

[0098] A perovskite solar cell containing a perylene diimide compound in the interface passivation layer and the electron transport layer is prepared as follows:

[0099] The preparation process is basically the same as that of Example 6, except that the thickness of the interface passivation layer and the electron transport layer based on the "compound 6" molecule in step d is 45 nm.

[0100] Example 10.

[0101] A perovskite solar cell containing a perylene diimide compound in the interface passivation layer and the electron transport layer is prepared as follows:

[0102] The preparation process is basically the same as that of Example 6, except that the thickness of the interface passivation layer and the electron transport layer based on the "compound 6" molecule in step d is 10 nm.

[0103] Example 11.

[0104] Preparation of perovskite thin film.

[0105] Cleaning of quartz glass substrate: The quartz glass is ultrasonically cleaned with glass cleaning solution, deionized water, ethanol, isopropanol, then dried at 200 degrees Celsius, blown dry with nitrogen flow, and then subjected to ultraviolet ozone cleaning for 15 minutes to obtain clean quartz glass as the thin film substrate.

[0106] Preparation of perovskite thin film on quartz glass: CsI, FAI, PbI2, PbBr2 are configured into a solution in a molar ratio of 2:8:4:6, with a concentration of 1.2M, and a solvent of DMF and DMSO solution in a volume ratio of 4:1. After stirring for 2 hours to ensure complete dissolution, the clear solution is filtered to obtain a solution containing FA 0.8 Cs 0.2 Pb(I 0.6 Br 0.4)3) of the perovskite precursor solution. Take 100 μl of the perovskite precursor solution and drop it onto the surface of the quartz glass substrate, use a spin coater to spin, the rotation speed is 4000 rpm, the spin time is 32 s, add 100 ul of chlorobenzene as an anti-solvent at the 24th second, annealing treatment, annealing temperature is 100℃, annealing time is 10 min, to form a perovskite thin film.

[0107] Example 12.

[0108] Preparation of perovskite / C 60 thin film

[0109] On the basis of the perovskite thin film prepared in Example 11, an electron transport layer is prepared: 25 nm of fullerene (C 60 ) is deposited on the perovskite thin film by vacuum evaporation method, the evaporation rate is controlled at about 0.1 nm / s, to form an electron transport layer, to obtain a perovskite / C 60 thin film.

[0110] Example 13.

[0111] Preparation of perovskite / interface passivation layer / C 60 thin film

[0112] On the basis of the perovskite thin film prepared in Example 11, an interface passivation layer is prepared: the "compound 6" molecule prepared in Example 1 is dissolved in isopropanol to form a solution with a concentration of 20 mg / mL, which is spin-coated on the surface of the perovskite light-absorbing layer formed in the third step, using a spin coater to spin, the rotation speed is 2000 rpm, the spin time is 20 s, annealing treatment, annealing temperature is 100℃, annealing time is 10 min, to form an interface passivation layer.

[0113] 25 nm of fullerene (C 60 ) is deposited on the interface passivation layer by vacuum evaporation method, the evaporation rate is controlled at about 0.1 nm / s, to form an electron transport layer, to obtain a perovskite / interface passivation layer / C 60 thin film.

[0114] Comparative Example 1.

[0115] Preparation of a perovskite solar cell without containing an interface passivation layer, as follows:

[0116] The preparation process is basically the same as that of Example 2, except that there is no step 4).

[0117] Examples 2 to 10 and Comparative Example 1 are tested.

[0118] The method for testing is as follows: the open-circuit voltage of the perovskite solar cell of the embodiment and the comparative example is tested, the short-circuit current is tested, the fill factor is tested, the conversion efficiency is tested, and the related parameter test is performed according to the group standard of China Photovoltaic Industry Association “Current-voltage (I-V) characteristic measurement method of perovskite photovoltaic cells and modules”. Specifically, the light source is selected as a G2VPico type light source, and the light source level is AAA. The current and voltage data are collected by a source table, and the fill factor and conversion efficiency are calculated according to the current-voltage curve. The test results are shown in Table 1:

[0119] Table 1.

[0120]

[0121] From Table 1, it can be seen that:

[0122] The test results of Examples 2 to 5 show that introducing a benzylamine group into perylene diimide can achieve the effect of inhibiting interface recombination. Within a certain range, as the concentration of “compound 6” increases, the thickness of the interface passivation layer increases, the open-circuit voltage is significantly improved, and finally the conversion efficiency is improved. Among them, the optimal Example 2 introduces a layer of “compound 6” molecules between the perovskite and the C 60 , and the open-circuit voltage is improved by 0.12V, and the final cell conversion efficiency is improved by 3.3%. By further increasing the concentration of “compound 6” molecules based on Example 2, it is found that the short-circuit current decreases, but the open-circuit voltage does not decrease significantly, indicating that the interface passivation layer can inhibit interface recombination, but the electron mobility is not as good as the traditional C 60 , resulting in a decrease in electron extraction.

[0123] The test results of Examples 6 to 10 show that the “compound 6” molecule can be directly used as an electron transport layer. Compared with the use of C 60 as the electron transport layer in Comparative Example 1, the open-circuit voltage of Examples 6 to 9 is higher than that of Comparative Example 1, indicating that using the “compound 6” molecule as the electron transport layer can effectively inhibit interface recombination and thus improve the open-circuit voltage.

[0124] The test results of Example 9 show that an excessively thick electron transport layer is not conducive to electron transport, and its current density is lower than that of Examples 6 to 8 and Comparative Example 1.

[0125] The test results of Example 10 show that an excessively thin electron transport layer can cause charge transport imbalance, and its efficiency is much lower than that of Examples 6 to 9 and Comparative Example 1.

[0126] The perovskite thin film, perovskite / C 60 thin film, perovskite / interface passivation layer / C 60Photoluminescence quantum yield (PLQY) of the thin film.

[0127] The method of testing is as follows: the blank quartz glass (as a blank group) is placed in an integrating sphere, the integrating sphere is connected with a 442 nm laser and a detector through an optical fiber. The luminescence spectrum and its intensity under the condition of the blank group are tested. Then the blank quartz glass is taken out, the quartz glass coated with the sample is placed in the integrating sphere, the laser power is unchanged, and the luminescence spectrum and its intensity under the condition of the experimental group are tested.

[0128] Wherein, the PLQY is calculated according to the following formula:

[0129] PLQY = (P 600-900nm test group - P 600-900 nm blank group) / (P 400-600nm test group - P 400-600nm blank group)

[0130] P 600-900 nm represents the sum of the number of photons in the 600-900 nm band, which can be obtained by integrating the luminescence spectrum.

[0131] The quasi-Fermi level splitting (QFLS) can be calculated from the PLQY, and the high and low of the QFLS can measure the non-radiative recombination loss of the thin film, and the calculation formula is as follows:

[0132] QFLS = kBTln(PLQY x S x JG / J 0,rad)

[0133] Wherein, kB is the Boltzmann constant, T is the temperature, S is the equivalent excitation intensity of sunlight, JG is the current density generated under 1 sun (obtained from the device JSC), and J0,rad is the radiative recombination current in the dark (obtained from the dark current value of the Shockley-Queisser limit).

[0134] The test results are as follows:

[0135] Figure 4 The PLQY values of the perovskite thin film, perovskite / C 60 thin film, perovskite / interface passivation layer / C 60 thin film are shown in the distribution diagram.

[0136] Table 2 shows the QFLS values of the perovskite thin film, perovskite / C 60 thin film, perovskite / interface passivation layer / C 60 thin film.

[0137] Table 2.

[0138] Test object QFLS value (in eV) Perovskite thin film 1.301 perovskite / c 60 thin film 1.224 perovskite / interface passivation layer / c 60 thin film 1.293

[0139] According to Figure 4 and Table 2, the PLQY of the perovskite film was measured to calculate the QFLS result, which shows that the C 60 will cause serious interface recombination, resulting in a decrease in QFLS. This is consistent with the results of existing reported documents. However, the addition of the interface passivation layer material provided in the embodiments of the present application at the interface between the perovskite and the C 60 The decrease in QFLS compared to the pure film is significantly reduced, and the decrease in QFLS is 1.301-1.224 without the interface passivation layer and 1.301-1.293 with the interface passivation layer. The change in QFLS can reflect the loss of open circuit voltage, indicating that after adding the interface passivation layer, most of the interface recombination is inhibited, and the loss of open circuit voltage is reduced.

[0140] Although several embodiments of the present application have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Many modifications, changes and substitutions can be made by those skilled in the art without departing from the spirit and scope of the present application. It should be understood that various alternatives to the embodiments of the present application described herein can be employed in practicing the present application. The appended claims are intended to define the scope of the present application and thus cover equivalents or alternatives within the scope of these claims.

[0141] The collection and acquisition of various data in this application comply with relevant legal regulations and are authorized by the data provider. Any organization or individual that needs to obtain external data should obtain authorization and ensure data security in accordance with the law, and shall not illegally collect, use, process, transmit, sell, provide or disclose unauthorized or unprotected data.

Claims

1. A perylene diimide compound, characterized in that, The general chemical formula of the perylene diimide compounds is shown in formula (i): R1 is selected from 3-aminophenyl and 4-aminophenyl; Wherein, R2 is selected from alkyl groups with chain lengths of C1-C12 and aromatic groups with chain lengths of C5-C12; X is selected from chlorine, bromine, and iodine.

2. The perylene diimide compound according to claim 1, characterized in that, The chemical formula of the perylene diimide compound is shown in formula (ii):

3. The use of the perylene diimide compound according to any one of claims 1 to 2 as an interface passivator for perovskite solar cells.

4. A perovskite battery, characterized in that, The perovskite solar cell comprises a first electrode layer, a hole transport layer, a perovskite light-absorbing layer, an interface passivation layer, an electron transport layer, and a second electrode layer, stacked sequentially. The interface passivation layer comprises a perylene diimide compound as described in any one of claims 1 to 2.

5. The perovskite solar cell according to claim 4, characterized in that, The first electrode layer includes a metal electrode or a transparent oxide electrode; The second electrode layer includes a metal electrode or a transparent oxide electrode.

6. The perovskite solar cell according to claim 4, characterized in that, The hole transport layer includes NiO. x One or more of PTAA, 2-PACz, and Me-4PACz.

7. The perovskite solar cell according to claim 4, characterized in that, The electron transport layer comprises a perylene diimide compound as described in any one of claims 1 to 3.

8. The perovskite solar cell according to claim 4, characterized in that, The perovskite in the perovskite light-absorbing layer has the structural formula ABX3. in: A is selected from CH3NH3 + (MA + ), CH2(NH3)2(FA + ), Cs + A mixture of one or more of them; B is selected from Pb 2+ Sn 2+ A mixture of one or two of them; X is selected from I - ,Br - Cl - A mixture of one or more of them.

9. A method for preparing a perovskite solar cell, characterized in that, Prepare the first electrode layer; A hole transport layer is formed on the first electrode layer; A perovskite light-absorbing layer is formed on the hole transport layer; An interface passivation layer and an electron transport layer are formed on the perovskite light-absorbing layer, wherein the interface passivation layer and the electron transport layer comprise a perylene diimide compound as described in any one of claims 1 to 2; A second electrode layer is formed on the electron transport layer.

10. A method for preparing a perovskite solar cell, characterized in that, Prepare the first electrode layer; A hole transport layer is formed on the first electrode layer; A perovskite light-absorbing layer is formed on the hole transport layer; An interface passivation layer is formed on the perovskite light-absorbing layer, the interface passivation layer comprising a perylene diimide compound as described in any one of claims 1 to 2; An electron transport layer is formed on the interface passivation layer; A second electrode layer is formed on the electron transport layer.

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