Preparation method of electron transport layer of perovskite cell, perovskite cell and electron transport material

Abstract

The invention discloses a preparation method of an electron transport layer of a perovskite battery, the perovskite battery and an electron transport material, and belongs to the technical field of perovskite batteries. According to the invention, the small organic molecule transport material is applied to the preparation of the electron transport layer, so that the contact between the lower interface of the perovskite active layer and the transparent conductive oxide coated glass can be well improved, and the charge recombination at the lower interface of the perovskite active layer is reduced, thereby improving the energy conversion efficiency and stability of the perovskite cell.

Description

Technical Field

[0001] The present invention relates to the technical field of perovskite cells, and in particular to a method for preparing an electron transport layer of a perovskite cell, a perovskite cell, and an electron transport material. Background Art

[0002] Tin oxide nanoparticles are widely used in perovskite cells due to their ease of film formation. However, inherent defects and agglomeration of tin oxide nanoparticles, as well as limited tunability and instability in post-processing processes, have hindered the further development of orthogonal perovskite cells. Furthermore, the lengthy synthesis and purification steps required for conventional organic electron transport materials also hinder the commercialization of orthogonal perovskite cells. Therefore, developing an alternative preparation method for electron transport layers is of great significance and could fill the gap in perovskite cell electron transport layers. Summary of the Invention

[0003] Based on the background technology, the main purpose of the present invention is to provide a method for preparing an electron transport layer of a perovskite battery, a perovskite battery and an electron transport material.

[0004] To achieve the above object, the present invention provides a method for preparing an electron transport layer of a perovskite battery, comprising the following steps:

[0005] dispersing an electron transport material in an organic solvent to obtain an electron transport layer precursor solution;

[0006] The electron transport layer precursor solution is applied to the surface of the substrate to form the electron transport layer;

[0007] The electron transport material includes an organic small molecule transport material, and the organic small molecule transport material includes the following structural formula:

[0008]

[0009] In some embodiments of the present invention, the method for preparing the organic small molecule transport material comprises the following steps:

[0010] Compound A, 2,5-bis(trimethylstannyl)thiophene, 2Pd2(dba)3 and P(o-Tol)3 are mixed and added to toluene, oxygen is removed, and the mixture is heated under reflux to react to obtain a reactant, the reactant is washed, extracted, and dried to obtain a crude product, and the crude product is purified to obtain the organic small molecule transport material;

[0011] The compound A has the following structural formula:

[0012]

[0013] In some embodiments of the present invention, the molar ratio of compound A, 2,5-bis(trimethylstannyl)thiophene, 2Pd2(dba)3 and P(o-Tol)3 is (1.5-3.5):1:(0.028-0.048):(0.35-0.4);

[0014] And / or, the reaction temperature of the heating reflux reaction is 100° C. to 115° C.;

[0015] And / or, the reaction time of the heating reflux reaction is 22h to 25h;

[0016] and / or, the washing step comprises a detergent, wherein the detergent comprises water;

[0017] and / or, the extraction step comprises an extractant comprising dichloromethane;

[0018] and / or, in the drying step, the reactant is dried using a desiccant;

[0019] And / or, the drying method comprises rotary evaporation;

[0020] and / or, the purification method comprises column chromatography;

[0021] And / or, the purification comprises an eluent, and the eluent comprises n-hexane and dichloromethane.

[0022] In some embodiments of the present invention, the organic solvent includes isopropyl alcohol.

[0023] In some embodiments of the present invention, the amount of the organic small molecule transport material added is (0.3-5) mg / ml;

[0024] And / or, the thickness of the electron transport layer is 5 nm to 30 nm;

[0025] And / or, after the electron transport layer precursor solution is coated on the surface of the substrate, an annealing treatment is performed to obtain the electron transport layer.

[0026] In some embodiments of the present invention, the substrate includes transparent conductive oxide-coated glass, and the electron transport layer is prepared on the surface of the transparent conductive oxide-coated glass.

[0027] The present invention also provides a perovskite battery, which includes an electron transport layer prepared by the above-mentioned method for preparing the electron transport layer of the perovskite battery.

[0028] In some embodiments of the present invention, the perovskite cell further includes a transparent conductive oxide layer and a perovskite active layer, the electron transport layer is disposed on the surface of the transparent conductive oxide layer, and the perovskite active layer is disposed on the surface of the electron transport layer.

[0029] In some embodiments of the present invention, the perovskite cell includes the transparent conductive oxide layer, the electron transport layer, the perovskite active layer, the hole transport layer and the back electrode layer stacked in sequence.

[0030] The present invention also provides an electron transport material for use in preparing an electron transport layer of a perovskite battery. The electron transport material comprises an organic small molecule transport material, and the organic small molecule transport material comprises the following structural formula:

[0031]

[0032] The beneficial effects that can be achieved by the present invention are:

[0033] The present invention adds an A1-A2-D-A2-A1 type non-fullerene organic small molecule transport material when preparing the electron transport layer of the perovskite battery. The electron transport layer prepared in this way can not only promote electron transport, but also effectively improve the contact between the lower interface of the perovskite active layer and the transparent conductive oxide-coated glass (ITO), reduce charge recombination at the lower interface of the perovskite active layer, and thus improve the energy conversion efficiency and stability of the perovskite battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 any creative work.

[0035] Figure 1 Schematic diagram of a process for preparing an organic small molecule transport material according to an embodiment of the present invention.

[0036] Figure 2 2 is a current density-voltage curve diagram of the perovskite cells prepared in Examples 1 to 5 and Comparative Examples 1 to 3 of the present invention.

[0037] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0038] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0039] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0040] In the present invention, descriptions such as "first" and "second" are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly indicating the number of the technical features indicated. Therefore, features defined as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions of various embodiments may be combined with each other, but this must be based on the fact that they can be implemented by a person of ordinary skill in the art. If the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0041] The present invention provides a method for preparing an electron transport layer of a perovskite battery, comprising the following steps: dispersing an electron transport material in an organic solvent to obtain an electron transport layer precursor solution; and coating the electron transport layer precursor solution on the surface of a substrate to form an electron transport layer.

[0042] Electron transport materials include organic small molecule transport materials, and organic small molecule transport materials include the following structural formulas:

[0043]

[0044] The above-mentioned organic small molecule transport material has an A1-A2-D-A2-A1 structure and belongs to a class of non-fullerene electron transport materials. The electron transport layer prepared therefrom can not only promote electron transport, but also better improve the contact between the lower interface of the perovskite active layer and the transparent conductive oxide-coated glass (ITO), reduce the charge recombination at the lower interface of the perovskite active layer, and thus improve the energy conversion efficiency and stability of the perovskite battery.

[0045] In some embodiments, the method for preparing the organic small molecule transport material of the present invention comprises the following steps:

[0046] Compound A, 2,5-bis(trimethylstannyl)thiophene, 2Pd2(dba)3 and P(o-Tol)3 are mixed and added to toluene, oxygen is removed, and the mixture is heated under reflux to obtain a reactant, the reactant is washed, extracted and dried to obtain a crude product, and the crude product is purified to obtain an organic small molecule transport material;

[0047] Compound A has the following structural formula:

[0048]

[0049] Compound A of the present invention can be obtained from commercial sources or prepared by preparation methods known in the art.

[0050] The Chinese name of 2Pd2(dba)3 is tris(dibenzylideneacetone)dipalladium, and the Chinese name of P(o-Tol)3 is tris(o-methylphenyl)phosphine. It is used as a catalyst in the preparation of electron transport materials and can promote the reaction of compound A and 2,5-bis(trimethylstannyl)thiophene to generate electron transport materials.

[0051] In some embodiments, the molar ratio of Compound A, 2,5-bis(trimethylstannyl)thiophene, 2Pd2(dba)3 and P(o-Tol)3 is (1.5-3.5):1:(0.028-0.048):(0.35-0.4).

[0052] In some embodiments, the molar ratio of Compound A, 2,5-bis(trimethylstannyl)thiophene, 2Pd2(dba)3, and P(o-Tol)3 is 0.195:0.078:0.003:0.03.

[0053] In some embodiments, the reaction temperature of the heating reflux reaction is 100° C. to 115° C., and may be 110° C., which can promote the reaction of compound A and 2,5-bis(trimethylstannyl)thiophene to obtain an organic small molecule transport material.

[0054] In some embodiments, the heating reflux reaction time is 22 hours to 25 hours, and can be 24 hours, which can promote the complete reaction of compound A and 2,5-bis(trimethylstannyl)thiophene and increase the yield of the organic small molecule transport material.

[0055] In the present invention, washing the reactants can remove impurities and improve the purity of the final product, the organic small molecule transport material. In some embodiments, washing is performed using a detergent, which includes water.

[0056] In the present invention, the target product can be extracted by extraction. In some embodiments, the extraction is performed using an extractant, which includes dichloromethane.

[0057] In some embodiments, in the drying step, the reactants are dried using a desiccant, and the desiccant comprises anhydrous sodium sulfate.

[0058] In some embodiments, the drying method includes rotary evaporation, which uses a rotary evaporator to accelerate the volatilization of the solvent in the reactants.

[0059] In some embodiments, the method of purification comprises column chromatography.

[0060] In some embodiments, the purification method comprises column chromatography, and the eluents used include n-hexane and dichloromethane.

[0061] In some embodiments, reference Figure 1 The synthesis path of the organic small molecule transport material is as follows: Compound A and 2,5-bis(trimethylstannyl)thiophene are reacted to obtain the organic small molecule transport material.

[0062] In some embodiments, the preparation method of the organic small molecule transport material comprises the following steps: Compound A, 2,5-bis(trimethylstannyl)thiophene, 2Pd2(dba)3 and P(o-Tol)3 are added to a 50 ml double-necked flask in a molar ratio of 0.195:0.078:0.003:0.03, and then toluene is added under nitrogen protection. After nitrogen is purged three times to remove oxygen, the mixture is heated to 100°C to 115°C and refluxed for 22h to 25h to obtain a reactant, and the reactant is cooled to room temperature. , washing the reactant with water, and extracting the reactant three times with dichloromethane, then using anhydrous Na2SO4 and a rotary evaporator to dry the reactant to obtain a crude product, and then using column chromatography to purify the crude product to obtain a pure product. The eluent used for column chromatography is n-hexane and dichloromethane in a volume ratio of 5:1. Finally, CH2Cl2 in the pure product is removed by rotary evaporation to obtain a solid product electron transport material organic small molecule transport material, which can be represented by RDN-BT-T-BT-RDN.

[0063] In some embodiments, in the step of preparing the electron transport layer precursor solution, the organic solvent for dissolving the organic small molecule transport material includes isopropyl alcohol.

[0064] In some embodiments, the amount of organic small molecule transport material added to the electron transport layer precursor solution is (0.3~5) mg / ml, for example, it can be 0.3 mg / ml, 0.4 mg / ml, 0.5 mg / ml, 0.8 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, etc.

[0065] In some embodiments, after the organic small molecule transport material is added to the organic solvent, it is further stirred and dispersed, which can accelerate the dissolution of the organic small molecule transport material and uniformly disperse it in the organic solvent.

[0066] In some embodiments, the thickness of the electron transport layer is 5 nm to 30 nm.

[0067] In some embodiments, the substrate includes transparent conductive oxide-coated glass, an electron transport layer is prepared on the surface of the transparent conductive oxide-coated glass, and then functional layers such as a perovskite active layer are sequentially prepared to obtain an upright perovskite cell. The electron transport layer containing an organic small molecule transport material can not only exert the electron transport layer's own function of promoting electron transport, but also effectively improve the contact between the lower interface of the perovskite active layer and the transparent conductive oxide-coated glass, reduce charge recombination at the lower interface of the perovskite active layer, and thus improve the energy conversion efficiency and stability of the perovskite cell.

[0068] In the present invention, the electron transport layer precursor solution can be coated on the surface of the substrate by referring to the commonly used methods in the art.

[0069] For example, the electron transport layer is coated onto the surface of the substrate by spin coating, the spin coating speed is 2800rpm~3200rpm, which can be 3000rpm, and the spin coating time is 25s~35s, which can be 26s, 28s, 30s, or 32s, which is conducive to obtaining an electron transport layer with appropriate and uniform thickness.

[0070] In some embodiments, after the electron transport layer precursor solution is coated on the surface of the substrate, annealing treatment is performed. The annealing temperature is 95°C to 105°C, and can be 100°C. The annealing time is 3 minutes to 6 minutes, and can be 5 minutes, to remove residual solvent.

[0071] In some embodiments, when the electron transport layer is prepared using the method of the present invention, the electron transport material, in addition to the organic small molecule transport material of the present invention, may also include other electron transport materials commonly used in ortho-perovskite cells, such as metal oxides tin dioxide, titanium dioxide, etc., as well as organic molecular materials.

[0072] The present invention also provides a perovskite battery, which includes an electron transport layer prepared by the above-mentioned preparation method of the electron transport layer of the perovskite battery, and at least has all the beneficial effects of the above-mentioned organic small molecule transport materials used in the preparation of the electron transport layer.

[0073] In some embodiments, the perovskite cell further includes a transparent conductive oxide layer and a perovskite active layer. The electron transport layer is disposed on the surface of the transparent conductive oxide layer, and the perovskite active layer is disposed on the surface of the electron transport layer. The electron transport layer contains an organic small molecule transport material. The electron transport layer can effectively improve the contact between the lower interface of the perovskite active layer and the transparent conductive oxide-coated glass, reduce the charge recombination at the lower interface of the perovskite active layer, and thus improve the energy conversion efficiency and stability of the perovskite cell.

[0074] In some embodiments, the perovskite cell includes a transparent conductive oxide layer, an electron transport layer, a perovskite active layer, a hole transport layer, and a back electrode stacked in sequence.

[0075] In some embodiments, the material for preparing the transparent conductive oxide layer includes transparent conductive oxide-coated glass, for example, including at least one of indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), fluorine-doped tin oxide (FTO) and antimony-doped tin oxide (ATO).

[0076] In some embodiments, other functional layers known in the art are further included between the perovskite active layer and the hole transport layer, and between the hole transport layer and the back electrode.

[0077] Illustratively, the perovskite cell of the present invention includes a transparent conductive oxide layer, an electron transport layer, a perovskite active layer, a hole transport layer, a hole blocking layer, and a back electrode stacked in sequence. A hole blocking layer is designed between the hole transport layer and the back electrode to prevent carrier recombination and improve the energy conversion efficiency of the perovskite cell.

[0078] The present invention also provides a method for preparing the above-mentioned perovskite battery, which includes the steps of preparing the electron transport layer of the perovskite battery as described above.

[0079] In some embodiments, the method for preparing a perovskite cell further includes the steps of: preparing a transparent conductive oxide layer; preparing an electron transport layer on the surface of the transparent conductive oxide layer using the above-mentioned preparation steps for preparing a perovskite electron transport layer; and preparing a perovskite active layer on the surface of the electron transport layer. In the step of preparing the transparent conductive oxide layer, the transparent conductive oxide layer includes transparent conductive oxide-coated glass, and the transparent conductive oxide-coated glass can be cleaned before use. In the step of preparing the perovskite active layer, a perovskite material well known in the art can be dissolved in a solvent to obtain a perovskite precursor solution, and the perovskite precursor solution is applied to the surface of the electron transport layer and annealed. In this embodiment, the electron transport layer is provided between the transparent conductive oxide layer and the perovskite active layer, which can better improve the contact between the lower interface of the perovskite active layer and the transparent conductive oxide-coated glass, reduce charge recombination at the lower interface of the perovskite active layer, and thus improve the energy conversion efficiency and stability of the perovskite cell.

[0080] In some embodiments, the preparation method of the perovskite battery also includes the preparation of functional layers such as a hole transport layer and a back electrode. For example, a hole transport layer is prepared on the surface of the perovskite active layer, and a back electrode is prepared on the surface of the hole transport layer. Both the hole transport layer and the back electrode can be prepared by referring to the preparation steps well known in the art.

[0081] The present invention also provides an electron transport material for use in preparing an electron transport layer of a perovskite battery. The electron transport material includes an organic small molecule transport material, and the organic small molecule transport material includes the following structural formula:

[0082]

[0083] The above-mentioned organic small molecule transport material is used to prepare the electron transport layer of the perovskite battery, which is arranged between the transparent conductive oxide layer and the perovskite active layer. It can better improve the contact between the lower interface of the perovskite and the transparent conductive oxide coated glass, reduce the charge recombination at the lower interface of the perovskite, and thus improve the energy conversion efficiency and stability of the perovskite battery.

[0084] The technical solutions of the present invention are further described in detail below in conjunction with specific embodiments. It should be understood that the following specific embodiments are only used to explain the present invention and are not used to limit the present invention.

[0085] Example 1

[0086] 1. Synthesize organic small molecule transport materials

[0087] Compound A (75.33 mg, 0.195 mmol), 2,5-bis(trimethylstannyl)thiophene (32 mg, 0.078 mmol), 2Pd2(dba)3 (2.7 mg, 0.003 mmol) and P(o-Tol)3 (9.1 mg, 0.03 mmol) were added to a 50 ml double-necked flask, and then toluene was added under nitrogen protection. After nitrogen was purged three times to remove oxygen, the mixture was heated to 110 ° C for reflux reaction for 24 hours to obtain the reaction product. The reaction was cooled to room temperature, washed with water, and extracted three times with dichloromethane. The reactant was then dried using anhydrous Na2SO4 and a rotary evaporator to obtain a crude product, which was then purified by column chromatography to obtain a pure product. The eluent used for column chromatography was n-hexane and dichloromethane in a volume ratio of 5:1. The dichloromethane in the pure product was removed by rotary evaporation to obtain a solid product, an organic small molecule transport material (46.56 mg, yield 85.90%).

[0088] 2. Preparation of perovskite cells

[0089] Cleaning of ITO conductive glass

[0090] The protective film on the surface of the ITO conductive glass was removed, and the glass was ultrasonically cleaned with deionized water containing detergent, and then ultrasonically treated in deionized water, acetone, and isopropyl alcohol for 20 minutes in sequence.

[0091] Preparation of electron transport layer

[0092] A glass bottle was ultrasonically cleaned with deionized water, dichloroethane, and isopropyl alcohol in sequence, isopropyl alcohol and RDN-BT-T-BT-RDN were added to the glass bottle, and the solution was shaken for 30 minutes to uniformly disperse the RDN-BT-T-BT-RDN. The solution was then filtered to obtain a 2 mg / ml RDN-BT-T-BT-RDN solution.

[0093] Use a hot air gun to dry the cleaned ITO conductive glass and place it in a UV ozone treatment machine for ozone treatment for 20 minutes. Take it out and cool it to room temperature before placing it in a homogenizer. Use a pipette to drop 50 μl of RDN-BT-T-BT-RDN solution, and then start the spin coating program with a spin coating speed of 3000 rpm and a spin time of 30 seconds. After the spin coating is completed, place the ITO conductive glass coated with RDN-BT-T-BT-RDN on a hot plate at 100°C and anneal for 5 minutes to remove the solvent to obtain the RDN-BT-T-BT-RDN electron transport layer.

[0094] Preparation of perovskite active layer

[0095] 19.5 mg of CsI, 224.4 mg of FAI, and 661.2 mg of PbI2 were dissolved in 1 mL of a mixed solvent and stirred overnight at room temperature to fully dissolve them. The mixed solvent was anhydrous DMF and DMSO mixed in a volume ratio of 4:1 to obtain a component composition of CsI. 0.05 FA 0.95 The concentration of PbI3 is 1.5 mol·L -1 perovskite precursor solution.

[0096] The perovskite active layer was prepared by a one-step method: 50 μl of the perovskite precursor solution was transferred and spin-coated on the surface of the electron transport layer. The spin-coating procedure was 1000 rpm for 10 s and 5000 rpm for 30 s, and 100 μl of chlorobenzene was added within 20 to 25 s after the second spin-coating procedure was started. Then, the sample was annealed on a 100°C hot plate for 10 min to form a perovskite active layer.

[0097] Preparation of hole transport layer

[0098] In a glove box, 144.6 mg of Spiro-OMeTAD was weighed, and then 2 ml of ultra-dry chlorobenzene, 35 μl of Li-TFSI acetonitrile solution (concentration 520 mg mL) were added in sequence. -1), 56.8 μL of tributyl phosphate (tBP), sealed with parafilm, stirred at 60°C for 2 hours to fully dissolve, and then filtered to obtain a hole transport layer precursor solution for later use. The ITO conductive glass with the hole transport layer prepared was placed on a spin coater. 40 μL of the hole transport layer precursor solution was dropwise added to the surface of the perovskite active layer using a static spin coating method. The spin coating was performed at 4000 rpm for 30 seconds. Upon completion of the spin coating, the hole transport layer was obtained.

[0099] Preparation of metal electrodes

[0100] In a glove box, the ITO conductive glass containing the hole transport layer was placed in a metal vacuum evaporation chamber, and then a 100nm thick Ag electrode was evaporated on the surface of the hole transport layer to obtain a complete area of ​​0.06cm 2 perovskite battery devices.

[0101] Example 2

[0102] Example 2 A perovskite cell device was prepared by referring to the method of Example 1, except that the concentration of the organic small molecule transport material in the electron transport layer precursor solution was 0.3 mg / ml.

[0103] Example 3

[0104] Example 3 A perovskite cell device was prepared by referring to the method of Example 1, except that the concentration of the organic small molecule transport material in the electron transport layer precursor solution was 1 mg / ml.

[0105] Example 4

[0106] Example 4 A perovskite cell device was prepared by referring to the method of Example 1, except that the concentration of the organic small molecule transport material in the electron transport layer precursor solution was 3 mg / ml.

[0107] Example 5

[0108] Example 5 A perovskite cell device was prepared by referring to the method of Example 1, except that the concentration of the organic small molecule transport material in the electron transport layer precursor solution was 5 mg / ml.

[0109] Example 6

[0110] Example 6: An organic small molecule transport material was synthesized by referring to the preparation method of Example 1, except that the molar ratio of compound A, 2,5-bis(trimethylstannyl)thiophene, 2Pd2(dba)3 and P(o-Tol)3 was 3.5:1:0.028:0.35, and a perovskite cell was prepared using the organic small molecule transport material prepared in Example 6 by referring to the method of Example 1.

[0111] Example 7

[0112] Example 7: An organic small molecule transport material was synthesized by referring to the preparation method of Example 1, except that the molar ratio of compound A, 2,5-bis(trimethylstannyl)thiophene, 2Pd2(dba)3 and P(o-Tol)3 was 1.5:1:0.048:0.4, and a perovskite cell was prepared using the organic small molecule transport material prepared in Example 7 by referring to the method of Example 1.

[0113] Example 8

[0114] Example 8 synthesizes an organic small molecule transport material by referring to the preparation method of Example 1, except that the molar ratio of compound A, 2,5-bis(trimethylstannyl)thiophene, 2Pd2(dba)3 and P(o-Tol)3 is 3.0:1:0.04:0.4, and the organic small molecule transport material prepared in Example 8 is used to prepare a perovskite cell by referring to the method of Example 1.

[0115] Example 9

[0116] In Example 9, an organic small molecule transport material was synthesized by referring to the preparation method of Example 1, except that the heating reflux reaction was carried out at 115°C, and a perovskite cell was prepared using the organic small molecule transport material prepared in Example 9 by referring to the method of Example 1.

[0117] Example 10

[0118] Example 10: An organic small molecule transport material was synthesized by referring to the preparation method of Example 1, except that the reaction time was 25 h. A perovskite cell was prepared using the organic small molecule transport material prepared in Example 10 by referring to the method of Example 1.

[0119] Comparative Example 1

[0120] Comparative Example 1 A perovskite cell device was prepared by referring to the method of Example 1, except that the electron transport layer in Comparative Example 1 was prepared using SnO2 as the electron transport material.

[0121] Comparative Example 2

[0122] Comparative Example 2: A perovskite cell device was prepared by referring to the method of Example 1, except that in Comparative Example 1, an organic electron transport material anthraquinone (AQ) was used to prepare the electron transport layer.

[0123] Comparative Example 3

[0124] Comparative Example 3: A perovskite cell device was prepared by referring to the method of Example 1, except that, in Comparative Example 3, the electron transport layer was prepared using naphthalene diimide (NDI), an organic electron transport material.

[0125] Performance Testing

[0126] Under standard sunlight (AM 1.5G), the perovskite solar cells prepared in Examples 1 to 10 and Comparative Example 1 were subjected to device performance tests. The current density-voltage curves of the perovskite solar cells obtained in Examples 1 to 5 and Comparative Examples 1 to 3 are shown in FIG. Figure 2 As shown, the data is recorded in Table 1.

[0127] Table 1

[0128] Experimental group <![CDATA[Jsc(mA / cm 2 )]]> Voc(V) FF(%) PCF (%) Example 1 26.73 1.111 24.77 83.38 Example 2 26.83 1.017 21.38 78.35 Example 3 26.21 1.071 23.39 83.34 Example 4 26.66 1.103 24.17 82.17 Example 5 26.28 1.093 23.18 80.69 Example 6 26.71 1.110 23.16 83.64 Example 7 26.70 1.109 23.81 83.22 Example 8 26.69 1.105 22.69 83.01 Example 9 26.82 1.103 23.24 84.11 Example 10 26.68 1.059 22.64 83.89 Comparative Example 1 24.51 1.050 21.17 82.29 Comparative Example 2 26.49 0.907 19.42 80.81 Comparative Example 3 24.24 1.046 20.87 82.28

[0129] Combined with Table 1 and Figure 2 It can be seen that the perovskite solar cells of Examples 1 to 10 all achieved high photoelectric conversion efficiency and excellent performance. It can be seen that the use of organic small molecule transport materials as electron transport materials to prepare the electron transport layer can not only play the function of promoting electron transport, but also better improve the contact between the lower interface of the perovskite active layer and the transparent conductive oxide coated glass, reduce the charge recombination at the lower interface of the perovskite active layer, thereby improving the energy conversion efficiency and stability of the perovskite cell. Therefore, organic small molecule transport materials have great application potential as electron transport materials in the preparation of the electron transport layer of the normal perovskite cell, and provide reference and thinking for the design and synthesis of organic electron transport materials.

[0130] The above are only preferred embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for preparing an electron transport layer of a perovskite battery, characterized in that: The following steps are involved: dispersing an electron transport material in an organic solvent to obtain an electron transport layer precursor solution; The electron transport layer precursor solution is applied to the surface of the substrate to form the electron transport layer; The electron transport material includes an organic small molecule transport material, and the organic small molecule transport material includes the following structural formula:

2. The method for preparing the electron transport layer of the perovskite battery according to claim 1, characterized in that: The preparation method of the organic small molecule transport material comprises the following steps: Compound A, 2,5-bis(trimethylstannyl)thiophene, 2Pd2(dba)3 and P(o-Tol)3 are mixed and added to toluene, oxygen is removed, and the mixture is heated under reflux to react to obtain a reactant, the reactant is washed, extracted, and dried to obtain a crude product, and the crude product is purified to obtain the organic small molecule transport material; The compound A has the following structural formula:

3. The method for preparing the electron transport layer of the perovskite battery according to claim 2, characterized in that: The molar ratio of compound A, 2,5-bis(trimethylstannyl)thiophene, 2Pd2(dba)3 and P(o-Tol)3 is (1.5-3.5):1:(0.028-0.048):(0.35-0.4); And / or, the reaction temperature of the heating reflux reaction is 100° C. to 115° C.; And / or, the reaction time of the heating reflux reaction is 22h to 25h; and / or, the washing step comprises a detergent, wherein the detergent comprises water; and / or, the extraction step comprises an extractant comprising dichloromethane; and / or, in the drying step, the reactant is dried using a desiccant; And / or, the drying method comprises rotary evaporation; and / or, the purification method comprises column chromatography; And / or, the purification comprises an eluent, and the eluent comprises n-hexane and dichloromethane.

4. The method for preparing the electron transport layer of the perovskite battery according to claim 1, characterized in that: The organic solvent includes isopropyl alcohol.

5. The method for preparing the electron transport layer of the perovskite battery according to claim 1, characterized in that: The addition amount of the organic small molecule transport material is (0.3-5) mg / ml; And / or, the thickness of the electron transport layer is 5 nm to 30 nm; And / or, after the electron transport layer precursor solution is coated on the surface of the substrate, an annealing treatment is performed to obtain the electron transport layer.

6. The method for preparing the electron transport layer of a perovskite battery according to claim 1, characterized in that: The substrate includes transparent conductive oxide-coated glass, and the electron transport layer is prepared on the surface of the transparent oxide-coated glass.

7. A perovskite battery, characterized in that: The perovskite battery comprises an electron transport layer prepared by the method for preparing an electron transport layer of a perovskite battery according to any one of claims 1 to 6.

8. The perovskite cell according to claim 7, characterized in that The perovskite cell further includes a transparent conductive oxide layer and a perovskite active layer. The electron transport layer is disposed on the surface of the transparent conductive oxide layer, and the perovskite active layer is disposed on the surface of the electron transport layer.

9. The perovskite cell according to claim 8, characterized in that The perovskite cell includes the transparent conductive oxide layer, the electron transport layer, the perovskite active layer, the hole transport layer and the back electrode layer stacked in sequence.

10. An electron transport material used to prepare an electron transport layer of a perovskite battery, characterized in that: The electron transport material includes an organic small molecule transport material, and the organic small molecule transport material includes the following structural formula:

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