Application of non-fullerene receptor in perovskite solar cell

Abstract

The invention provides an application of a non-fullerene receptor in a perovskite solar cell. The perovskite solar cell comprises a transparent conductive substrate, a hole transport layer, a perovskite active layer, an electron transport layer and a metal electrode layer which are sequentially stacked, a functional layer is further arranged between the perovskite active layer and the electron transport layer, the material of the functional layer is a non-fullerene receptor, and the non-fullerene receptor has a structure shown in a formula (I). The non-fullerene acceptor with the specific structure is used as the functional layer to be applied to the perovskite solar cell, so that halogen ions in a perovskite active material can be anchored, interface defects can be effectively passivated, and meanwhile, the functional layer can form stepped arrangement with the energy levels of the perovskite active layer and the electron transport layer; the interface charge transfer between the perovskite active layer and the electron transfer layer can be effectively improved, so that the photoelectric conversion efficiency and the stability of the perovskite solar cell can be improved. # imgabs0 #

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to an application of a non-fullerene acceptor in a perovskite solar cell. Background Art

[0002] As a type of renewable energy, perovskite solar cells are expected to help achieve my country's carbon neutrality goals. Continuously improving the efficiency of perovskite cells is the technical basis for their commercialization. Among them, the interface modification of perovskite films can effectively reduce interface defects and change the hydrophobicity of the interface, thereby improving battery efficiency and stability. For example, small molecules such as 1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4), imidazole iodide (ImI), and tetrabutylammonium hexafluorophosphate (TBAPF6) are introduced between the perovskite and the charge transfer layer to passivate the interface of the perovskite active layer and adjust the energy level, but the passivation effect is limited and the absorption range cannot be increased.

[0003] In order to solve the above problems, some researchers applied the non-fullerene acceptor Y6 molecule to organic solar energy (OSC). However, there are few reports on the application of non-fullerene acceptor materials in perovskite solar cells.

[0004] Since the non-fullerene small molecule Y6 has good light absorption and electron affinity, some researchers have applied Y6 to perovskite solar cells, replacing all the electron transport materials PCBM in the trans-structured perovskite solar cells with Y6 to achieve interface passivation and improve stability. However, the electron mobility of Y6 is lower than that of PCBM, and the interface charge transfer capacity is poor, which is not conducive to further improving the battery performance; in addition, replacing all the electron transport materials PCBM with Y6 will lead to excessive use of Y6, and Y6 is expensive, resulting in high battery costs, which is not conducive to its commercial application.

[0005] Therefore, studying and developing a non-fullerene acceptor that can passivate interface defects and enhance interfacial charge extraction is of great significance for improving the photoelectric conversion efficiency and stability of perovskite solar cells. Summary of the invention

[0006] The main purpose of the present invention is to provide an application of a non-fullerene acceptor in a perovskite solar cell, so as to solve the problems in the prior art of using small molecules to passivate the interface of the perovskite active layer in the perovskite solar cell, such as poor passivation effect and insignificant improvement in interface charge transfer performance, which makes it difficult to significantly improve the photoelectric conversion efficiency and stability of the perovskite solar cell. At the same time, the non-fullerene small molecules in the prior art are high in cost, and when all of them replace electron transport materials, the battery preparation cost will be too high.

[0007] In order to achieve the above-mentioned object, the present invention provides a perovskite solar cell on one hand, which comprises a transparent conductive substrate, a hole transport layer, a perovskite active layer, an electron transport layer and a metal electrode layer stacked in sequence, characterized in that a functional layer is further arranged between the perovskite active layer and the electron transport layer, and the material of the functional layer is a non-fullerene receptor, and the non-fullerene receptor has a structure shown in formula (I):

[0008]

[0009] Wherein, R1 is selected from C4~C 16 An alkyl group, R2 is selected from C5~C 13 An alkyl group, R3 has a structure shown in formula (II),

[0010]

[0011] Wherein, X is a halogen atom.

[0012] Furthermore, the thickness of the functional layer is 2-20 nm; and / or the functional layer is prepared by spin coating or evaporation.

[0013] Furthermore, the thickness of the perovskite active layer is 300 to 1000 nm, and the material of the perovskite active layer is preferably selected from ABX3, wherein A is CH3NH3 + NH=CHNH3 + , Cs + or Rb + , B is Pb 2+ Sn 2+ Or Ge 2+ , X is a chlorine atom, Br, I, SCN - or COO - ; and / or, the thickness of the electron transport layer is 10 to 40 nm, and the material of the electron transport layer is preferably selected from PCB 61 M, C60, PCB 71 One or more of M and ICBA.

[0014] Furthermore, when the material of the perovskite active layer is MAPbI3, FAPbI3 or CsPbI3, R1 in the non-fullerene acceptor is selected from C8 to C 16 A straight or branched alkyl group, R2 is selected from C7~C 13 A straight chain or branched alkyl group, X is a fluorine atom, and the thickness of the functional layer is 2 to 20 nm; when the material of the perovskite active layer is MA 0.9 FA 0.1 PbI 3-x Cl x , Cs 0.1 FA 0.9PbI3 or MAPbI 3- x Cl x , wherein x is 0.1 to 0.6, and R1 in the non-fullerene acceptor is selected from C8 to C 12 A straight or branched alkyl group, R2 is selected from C9~C 11 A straight chain or branched alkyl group, X is a chlorine atom, and the thickness of the functional layer is 2 to 20 nm.

[0015] Furthermore, the non-fullerene acceptor is selected from any one or more of the following compounds:

[0016]

[0017]

[0018] Furthermore, the thickness of the hole transport layer is 10-40 nm; preferably, the material of the hole transport layer is selected from NiO x , Spiro-OMeTAD and PTAA.

[0019] Furthermore, the sheet resistance of the conductive surface of the transparent conductive substrate is 5-20Ω / sq, and the transparent conductive substrate is preferably selected from ITO conductive glass, FTO conductive glass or AZO conductive glass.

[0020] Furthermore, the thickness of the metal electrode layer is 50-200 nm; preferably, the material of the metal electrode layer is selected from one or more of Ag, Au, Cu and Al.

[0021] Furthermore, the perovskite solar cell also includes an interface modification layer, which is arranged between the electron transport layer and the metal electrode layer.

[0022] Furthermore, the thickness of the interface modification layer is 1-10 nm; preferably, the material of the interface modification layer is selected from one or more of BCP, MgO and LiF.

[0023] By applying the technical solution of the present invention, the present application applies the non-fullerene acceptor of the above-mentioned specific structure as a functional layer in perovskite solar cells. Compared with traditional small molecules such as 1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4), imidazolium iodide (ImI), tetrabutylammonium hexafluorophosphate (TBAPF6), etc., the non-fullerene acceptor of the above-mentioned specific structure has a longer alkyl side chain, a condensed ring structure, and contains a carbonyl group and a N atom, which can effectively transmit charges and form coordination bonds with lead ions in the perovskite active material, thereby anchoring the halogen ions in the perovskite active material, and can effectively passivate interface defects, thereby improving the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0024] Compared with directly using the above-mentioned non-fullerene acceptors for electron transport materials, setting a functional layer between the perovskite active layer and the electron transport layer can reduce the amount of the non-fullerene acceptors used. At the same time, the functional layer can form a stepped arrangement with the energy levels of the perovskite active layer and the electron transport layer, effectively improving the interfacial charge transfer between the perovskite active layer and the electron transport layer, thereby improving the photoelectric conversion efficiency of the perovskite solar cell and reducing the preparation cost of the perovskite solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0026] Figure 1 A schematic structural diagram of a perovskite solar cell prepared in Example 1 is shown;

[0027] Figure 2 A schematic structural diagram of the perovskite solar cell prepared in Comparative Example 1 is shown.

[0028] The above drawings include the following reference numerals:

[0029] 10. Transparent conductive substrate; 20. Hole transport layer; 30. Perovskite active layer; 40. Electron transport layer; 50. Metal electrode layer; 60. Functional layer; 70. Interface modification layer. DETAILED DESCRIPTION

[0030] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below in conjunction with the embodiments.

[0031] As described in the background technology, the existing small molecule passivation of the interface of the perovskite active layer in the perovskite solar cell has the problems of poor passivation effect and insignificant improvement in the interface charge transfer performance, which makes it difficult to significantly improve the photoelectric conversion efficiency and stability of the perovskite solar cell. At the same time, the cost of non-fullerene small molecules in the prior art is high, and when all of them replace the electron transport material, the battery preparation cost will be too high. In order to solve the above technical problems, the present application provides a perovskite solar cell, such as Figure 1 As shown, the perovskite solar cell includes a transparent conductive substrate 10, a hole transport layer 20, a perovskite active layer 30, an electron transport layer 40 and a metal electrode layer 50 which are stacked in sequence. A functional layer 60 is further provided between the perovskite active layer 30 and the electron transport layer 40. The material of the functional layer 60 is a non-fullerene acceptor, and the non-fullerene acceptor has a structure shown in formula (I):

[0032]

[0033] Wherein, R1 is selected from C4~C 16 An alkyl group, R2 is selected from C5~C 13 An alkyl group, R3 has a structure shown in formula (II),

[0034]

[0035] Wherein, X is a halogen atom.

[0036] The present application applies the above-mentioned non-fullerene acceptor with a specific structure as a functional layer 60 in a perovskite solar cell. Compared with traditional small molecules such as 1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4), imidazolium iodide (ImI), tetrabutylammonium hexafluorophosphate (TBAPF6), etc., the non-fullerene acceptor with a specific structure has a longer alkyl side chain, a condensed ring structure, and contains a carbonyl group and a N atom. It can effectively transmit charges and form coordination bonds with lead ions in perovskite active materials, thereby anchoring halogen ions in perovskite active materials, and can effectively passivate interface defects, thereby improving the photoelectric conversion efficiency and stability of perovskite solar cells.

[0037] Compared with directly using the above-mentioned non-fullerene acceptor as electron transport material, setting a functional layer 60 between the perovskite active layer 30 and the electron transport layer 40 can reduce the amount of the non-fullerene acceptor used. At the same time, the functional layer 60 can form a stepped arrangement with the energy levels of the perovskite active layer 30 and the electron transport layer 40, effectively improving the interfacial charge transfer between the perovskite active layer 30 and the electron transport layer 40, thereby improving the photoelectric conversion efficiency of the perovskite solar cell and reducing the preparation cost of the perovskite solar cell.

[0038] In a preferred embodiment, the thickness of the functional layer 60 is 2 to 20 nm. The thickness of the functional layer 60 includes but is not limited to the above range, and limiting it within the above range is beneficial to improving the passivation effect, and is also beneficial to reducing the interface charge transfer barrier between the two phases, thereby improving the photoelectric conversion efficiency of the perovskite solar cell.

[0039] In a preferred embodiment, the functional layer 60 is prepared by spin coating or evaporation. The above method is simple to operate and low in cost, and is suitable for preparing the functional layer 60.

[0040] In a preferred embodiment, the process of preparing the functional layer 60 by evaporation is as follows:

[0041] The transparent conductive substrate 10 prepared with the perovskite active layer 30 is placed in the evaporation chamber, and the non-fullerene acceptor represented by formula (I) is used as an evaporation source. -3 ~10 -6Pa vacuum degree, The functional layer 60 is obtained by evaporating the perovskite active layer 30 on the surface of the side away from the transparent conductive substrate 10 at a deposition rate of .

[0042] In a preferred embodiment, the thickness of the perovskite active layer 30 is 300-1000 nm. Compared with other ranges, limiting the thickness of the perovskite active layer 30 to the above range is conducive to improving light absorption rate, improving carrier transmission efficiency, and thus improving the photoelectric conversion efficiency of the perovskite solar cell.

[0043] In a preferred embodiment, the material of the perovskite active layer 30 includes but is not limited to ABX3, wherein A is CH3NH3 + NH=CHNH3 + , Cs + , or Rb + , B is Pb 2+ Sn 2+ Or Ge 2+ , X is a chlorine atom, Br, I, SCN - or COO - Compared with other types, the above perovskite active materials have smaller exciton binding energy, and when excited by external light, they easily generate free electron-hole pairs, have narrow band gaps and wide absorption spectrum, which is conducive to improving the photoelectric conversion efficiency of perovskite solar cells.

[0044] The electron transport material should be able to effectively transport electrons and block holes. In a preferred embodiment, the thickness of the electron transport layer 40 is 10 to 40 nm, and the material of the electron transport layer 40 preferably includes but is not limited to PCB. 61 M, C60, PCB 71 M and ICBA (1',1',4',4'-tetrahydro-di[1,4]methanenaphthalene [1,2:2',3',56,60:2',3'][5,6]fullerene-C60) or more. Compared with other ranges, limiting the thickness and composition of the electron transport layer 40 within the above range is conducive to suppressing electron recombination and increasing the electron transport rate, thereby facilitating the improvement of the photoelectric conversion efficiency of the perovskite solar cell; moreover, the electron mobility of the above-mentioned types of electron transport materials is significantly higher than that of non-fullerene acceptors. Compared with the battery structure in which the functional layer 60 is directly used as the electron transport layer 40, the above-mentioned battery structure provided by the present application is conducive to improving the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0045] In a preferred embodiment, when the material of the perovskite active layer 30 is MAPbI3, FAPbI3 or CsPbI3, R1 in the non-fullerene acceptor includes but is not limited to C8 to C16 A straight or branched alkyl group, R2 includes but is not limited to C7~C 13 A straight chain or branched alkyl group, X is a fluorine atom, and the thickness of the functional layer 60 is 2 to 20 nm. For a specific type of perovskite active layer 30 material, the use of the above-mentioned types of R1, R2 and R3 is beneficial to improving the passivation effect of the non-fullerene acceptor and improving the interface charge extraction efficiency, and is also beneficial to improving the solubility of the non-fullerene acceptor, facilitating its application in perovskite solar cells, thereby helping to improve the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0046] In a preferred embodiment, when the material of the perovskite active layer 30 is MA 0.9 FA 0.1 PbI 3-x Cl x , Cs 0.1 FA 0.9 PbI3 or MAPbI 3-x Cl x When x is 0.1 to 0.6, R1 in the non-fullerene acceptor includes but is not limited to C8 to C 12 A straight or branched alkyl group, R2 includes but is not limited to C9~C 11 A straight chain or branched alkyl group, X is a chlorine atom, and the thickness of the functional layer 60 is 2 to 20 nm. For a specific type of perovskite active layer 30 material, the use of the above types of R1, R2 and R3 is beneficial to improving the passivation effect of the non-fullerene acceptor and improving the interface charge extraction efficiency, and is also beneficial to improving the solubility of the non-fullerene acceptor, facilitating its application in perovskite solar cells, thereby helping to improve the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0047] In a preferred embodiment, the non-fullerene acceptor includes but is not limited to any one or more of the following compounds:

[0048]

[0049]

[0050] The use of the above-mentioned specific types of non-fullerene acceptors and their application in perovskite solar cells is beneficial to further improve the passivation effect and solubility of the non-fullerene acceptors, thereby further improving their processability, facilitating their application in perovskite solar cells, and further improving the photoelectric conversion efficiency and stability of perovskite solar cells.

[0051] In addition, it should be noted that the above-mentioned non-fullerene acceptors have good solubility in chloroform. When the functional layer 60 is prepared by spin coating, the non-fullerene acceptor can be mixed with chloroform to prepare a spin coating solution, preferably a spin coating solution with a mass concentration of 1 to 8 mg / mL.

[0052] In a preferred embodiment, the thickness of the hole transport layer 20 is 10 to 40 nm. The thickness of the hole transport layer 20 includes but is not limited to the above range, and limiting it within the above range is conducive to modifying the interface between the perovskite active layer 30 and the metal electrode layer 50, and is conducive to improving the hole transport rate without significantly affecting the absorption of light, thereby helping to improve the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0053] In a preferred embodiment, the material of the hole transport layer 20 is but not limited to NiO x , Spiro-OMeTAD (2,2',7,7'-tetrakis(N,N-di(4-methoxyphenyl)amino)-9,9'-spirobifluorene) and PTAA (poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine]). Among them, nickel oxide NiO x It has a high hole mobility (about 0.141cm 2 V -1 s -1 ), which has a wider band gap, is beneficial to suppress charge recombination and improve hole extraction efficiency as the material of the hole transport layer 20.

[0054] In a preferred embodiment, the sheet resistance of the conductive surface of the transparent conductive substrate 10 is 5 to 20Ω / sq. The sheet resistance includes but is not limited to the above range, and limiting it within the above range is conducive to improving the carrier transmission efficiency, thereby facilitating the improvement of the photoelectric conversion efficiency of the perovskite solar cell.

[0055] The present application has no particular limitation on the transparent conductive substrate 10, as long as it has high light transmittance, good conductivity and is easy to coat, and can be a conductive glass coated with a conductive film commonly used in the art. In a preferred embodiment, the transparent conductive substrate 10 includes but is not limited to ITO conductive glass, FTO conductive glass or AZO conductive glass.

[0056] The metal electrode layer 50 may be made of metal materials commonly used in the art. In a preferred embodiment, the thickness of the metal electrode layer 50 is 50-200 nm, and the material of the metal electrode layer 50 preferably includes but is not limited to one or more of Ag, Au, Cu, and Al.

[0057] In a preferred embodiment, the perovskite solar cell further comprises an interface modification layer 70, and the interface modification layer 70 is disposed between the electron transport layer 40 and the metal electrode layer 50. The provision of the interface modification layer 70 is beneficial to adjusting the energy level arrangement of the cathode interface, improving the electron extraction efficiency and blocking the hole transmission, thereby improving the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0058] In a preferred embodiment, the thickness of the interface modification layer 70 is 1 to 10 nm. The thickness of the interface modification layer 70 includes but is not limited to the above range, and limiting it within the above range is conducive to further adjusting the energy level arrangement of the cathode interface, further improving the electron extraction efficiency and blocking hole transmission, thereby further improving the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0059] In order to further improve the photoelectric conversion efficiency and stability of the perovskite solar cell, preferably, the material of the interface modification layer 70 includes but is not limited to one or more of BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), MgO and LiF.

[0060] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0061] Example 1

[0062] A method for preparing a perovskite solar cell, comprising:

[0063] (1) Preparation of transparent conductive substrate 10: ITO conductive glass (square resistance of 15Ω / sq) was ultrasonically cleaned with detergent water, deionized water, acetone, and isopropanol solution for 15 minutes, and dried with a nitrogen gun for later use; then, the ITO conductive glass was treated with ultraviolet ozone for 20 minutes, and transferred to a glove box for cooling and later use.

[0064] (2) Preparation of hole transport layer 20: 1 mmol Ni(Ac)2·4H2O was dissolved in 10 mL ethanol, 60 μL of ethanolamine solution with a molar ratio of 1:1 was added, wherein the molar ratio of Ni(Ac)2·4H2O to ethanolamine was 1:1, and then stirred at 70°C for 4 h to obtain NiO x Precursor: Take 90 μL of prepared NiO x The precursor solution was spin-coated on the conductive surface of the ITO conductive glass at a rotation speed of 4000 rpm for 30 seconds to obtain a hole transport layer 20 with a thickness of 25 nm.

[0065] (3) Preparation of perovskite active layer 30: A perovskite precursor solution was prepared using FAI and PbI2 (the molar ratio was 1:1), and the perovskite precursor solution used a mixed solvent of DMF and DMSO (the volume ratio of DMF to DMSO was 8:1). The perovskite film was then prepared by spin coating at 2500 rpm for 30 seconds and then at 5000 rpm for 15 seconds. The film was then immediately transferred to a hot plate at 150°C for annealing for 10 minutes to obtain a perovskite active layer 30 with a thickness of 500 nm.

[0066] (4) Preparation of functional layer 60: Compound 1 (Y6) was dissolved in chlorobenzene to obtain a 5 mg / mL 6 dispersion, which was heated and stirred at 60° C. for 4 h. The prepared Y6 dispersion was spin-coated on the surface of the perovskite active layer 30 to obtain a functional layer 60 with a thickness of 10 nm.

[0067] (5) Preparation of the electron transport layer 40: PCBM was dissolved in a chlorobenzene solution with a concentration of 20 mg / mL, heated and stirred at 60°C for 4 h, and filtered after cooling to obtain a PCBM precursor solution; 30 μL of the PCBM precursor solution was taken and spin-coated on the surface of the Y6 functional layer 60 at a speed of 2000 rpm for 30 s to obtain a PCBM layer with a thickness of 15 nm.

[0068] (6) Preparation of interface modification layer 70: BCP was dissolved in anhydrous ethanol at a concentration of 0.5 mg / mL, heated and stirred at 60°C for 1 h, and the BCP dispersion was spin-coated on the surface of the PCBM layer at a rotation speed of 4500 rpm. After annealing at 75°C for 10 min, a BCP interface modification layer 70 with a thickness of 5 nm was obtained.

[0069] (7) Preparation of metal electrode layer 50: A 100 nm thick Ag electrode was deposited on the surface of BCP by evaporation.

[0070] The structural schematic diagram of the perovskite solar cell prepared in Example 1 is as follows Figure 1 As shown, it includes a transparent conductive substrate 10, a hole transport layer 20, a perovskite active layer 30, a functional layer 60, an electron transport layer 40, an interface modification layer 70, and a metal electrode layer 50 which are stacked.

[0071] Among them, the preparation method of compound 1 is prepared with reference to the existing literature (Jun, Yuan, et al. Single-Junction Organic Solar Cell with over 15% Efficiency Using Fused-Ring Acceptor with Electron-Deficient Core. 2019, 3, 1140-1151.), and its synthesis route is as follows:

[0072]

[0073] The synthetic raw materials BT-CHO and F-EG can be purchased from Solarmer Material Inc.

[0074] Example 2

[0075] The difference from Example 1 is that in step (4), Compound 1 is replaced by Compound 2, and the dispersion of Compound 2 is spin-coated on the surface of the perovskite active layer 30 to obtain a functional layer 60 with a thickness of 10 nm. The remaining steps are the same as in Example 1.

[0076] Among them, the preparation method of compound 2 was prepared with reference to the existing literature (Xiaoling, Ma, et al. Achieving 17.4% Efficiency of Ternary Organic Photovoltaics with Two Well-Compatible Nonfullerene Acceptors for Minimizing Energy Loss. Adv. Energy Mater. 2020, 10, 2001404).

[0077] Example 3

[0078] The difference from Example 1 is that in step (4), Compound 1 is replaced by Compound 3, and the dispersion of Compound 3 is spin-coated on the surface of the perovskite active layer 30 to obtain a functional layer 60 with a thickness of 8 nm. The remaining steps are the same as in Example 1.

[0079] Among them, the preparation method of compound 3 was prepared with reference to the existing literature (Yong, Cui. et al. Over 16% Efficiency Organic Photovoltaic Cells Enabled by a Chlorinated Acceptor With Increased Open-circuit Voltages. Nat. Commun. 2019, 10, 2515).

[0080] Example 4

[0081] The difference from Example 1 is that in step (4), Compound 1 is replaced by Compound 4, and the dispersion of Compound 4 is spin-coated on the surface of the perovskite active layer 30 to obtain a functional layer 60 with a thickness of 8 nm. The remaining steps are the same as in Example 1.

[0082] Among them, the preparation method of compound 4 was prepared with reference to the existing literature (Yong, Cui, et al. Single-Junction Organic Photovoltaic Cells with Approaching 18% Efficiency. Adv. Mater. 2020, 32, 1908205).

[0083] Example 5

[0084] The difference from Example 1 is that the raw material for preparing the perovskite precursor solution in step (3) is changed, and the material of the prepared perovskite active layer 30 is FA 0.95 MA 0.05 PbI3; and by adjusting the rotation speed to 8000 rpm, the thickness of the functional layer 60 is 2 nm. The remaining steps are the same as those in Example 1.

[0085] Example 6

[0086] The difference from Example 1 is that the raw material for preparing the perovskite precursor solution in step (3) is changed, and the material of the prepared perovskite active layer 30 is FA 0.95 Cs 0.05 PbI3; and by adjusting the rotation speed to 800 rpm, the thickness of the functional layer 60 is 20 nm. The remaining steps are the same as those in Example 1.

[0087] Example 7

[0088] The difference from Example 1 is that the raw material for preparing the perovskite precursor solution in step (3) is changed, and the material of the prepared perovskite active layer 30 is FAPbI3; at the same time, by adjusting the rotation speed to 500 rpm, the thickness of the prepared functional layer 60 is 25 nm. The remaining steps are the same as Example 1.

[0089] Comparative Example 1

[0090] The difference from Example 1 is that the preparation of the PCBM layer is omitted, the compound 1 is directly used as the material of the electron transport layer 40, and the thickness of the electron transport layer 40 is the same as that of Example 1. The remaining steps are the same as those of Example 1.

[0091] The structural schematic diagram of the perovskite solar cell prepared in Comparative Example 1 is as follows Figure 2 As shown, it includes a transparent conductive substrate 10, a hole transport layer 20, a perovskite active layer 30, an electron transport layer 40, an interface modification layer 70, and a metal electrode layer 50 which are stacked.

[0092] The perovskite solar cell prepared in the device embodiment and device comparison example of the present application is placed under 100 mW / cm 2 The photovoltaic performance was tested under illumination of , and the test results are summarized in Table 1.

[0093] Table 1

[0094] <![CDATA[V oc / V]]> <![CDATA[J sc / mA cm 2 ]]> FF / % PCE / % Example 1 1.132 23.55 79.23 21.12 Example 2 1.126 23.06 79.68 20.69 Example 3 1.121 22.86 78.33 20.07 Example 4 1.135 22.63 79.92 20.53 Example 5 1.153 23.69 79.25 21.65 Example 6 1.162 23.28 80.09 21.67 Example 7 1.118 22.78 78.82 20.07 Comparative Example 1 1.103 21.63 77.66 18.53

[0095] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0096] Comparing Examples 1 to 7 of the present application and Comparative Example 1, it can be seen that compared to directly using the above-mentioned non-fullerene acceptor for the material of the electron transport layer 40, the functional layer 60 is provided between the perovskite active layer 30 and the electron transport layer 40. The amount of the non-fullerene acceptor can be reduced, while also ensuring that the electron transport layer 40 has a high electron mobility, and improving the charge transfer efficiency between the perovskite active layer 30 and the electron transport layer 40, thereby improving the photoelectric conversion efficiency of the perovskite solar cell and reducing the preparation cost of the perovskite solar cell. In addition, arranging the functional layer 60 between the perovskite active layer 30 and the electron transport layer 40 is also beneficial to reducing the roughness, which is beneficial to the subsequent preparation of the electron transport layer 40 on the surface of the functional layer 60.

[0097] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those described herein, for example.

[0098] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A perovskite solar cell, comprising a transparent conductive substrate (10), a hole transport layer (20), a perovskite active layer (30), an electron transport layer (40) and a metal electrode layer (50) stacked in sequence, characterized in that: A functional layer (60) is further provided between the perovskite active layer (30) and the electron transport layer (40), and the material of the functional layer (60) is a non-fullerene acceptor, and the non-fullerene acceptor has a structure shown in formula (I): Wherein, R1 is selected from C4~C 16 An alkyl group, R2 is selected from C5~C 13 An alkyl group, R3 has a structure shown in formula (II), Wherein, X is a halogen atom.

2. The perovskite solar cell according to claim 1, characterized in that The thickness of the functional layer (60) is 2-20 nm; and / or the functional layer (60) is prepared by spin coating or evaporation.

3. The perovskite solar cell according to claim 1 or 2, characterized in that: The thickness of the perovskite active layer (30) is 300-1000 nm. Preferably, the material of the perovskite active layer (30) is selected from ABX3, wherein A is CH3NH3 + NH=CHNH3 + , Cs + or Rb + , B is Pb 2+ Sn 2+ Or Ge 2+ , X is a chlorine atom, Br, I, SCN - or COO - and / or, The thickness of the electron transport layer (40) is 10-40 nm, and the material of the electron transport layer (40) is preferably selected from PCB 61 M, C60, PCB 71 One or more of M and ICBA.

4. The perovskite solar cell according to claim 3, characterized in that: When the material of the perovskite active layer (30) is MAPbI3, FAPbI3 or CsPbI3, the R1 in the non-fullerene acceptor is selected from C8 to C 16 A straight or branched alkyl group, wherein R2 is selected from C7 to C 13 A straight chain or branched alkyl group, X is a fluorine atom, and the thickness of the functional layer (60) is 2 to 20 nm; When the material of the perovskite active layer (30) is MA 0.9 FA 0.1 PbI 3-x Cl x , Cs 0.1 FA 0.9 PbI3 or MAPbI 3-x Cl x , wherein x is 0.1 to 0.6, and the R1 in the non-fullerene acceptor is selected from C8 to C 12 A straight or branched alkyl group, wherein R2 is selected from C9 to C 11 A straight chain or branched alkyl group, X is a chlorine atom, and the thickness of the functional layer (60) is 2 to 20 nm.

5. The perovskite solar cell according to any one of claims 1 to 4, characterized in that The non-fullerene acceptor is selected from any one or more of the following compounds:

6. The perovskite solar cell according to any one of claims 1 to 4, characterized in that The hole transport layer (20) has a thickness of 10 to 40 nm; Preferably, the material of the hole transport layer (20) is selected from NiO x , Spiro-OMeTAD and PTAA.

7. The perovskite solar cell according to any one of claims 1 to 4, characterized in that The sheet resistance of the conductive surface of the transparent conductive substrate (10) is 5 to 20Ω / sq. Preferably, the transparent conductive substrate (10) is selected from ITO conductive glass, FTO conductive glass or AZO conductive glass.

8. The perovskite solar cell according to any one of claims 1 to 4, characterized in that The thickness of the metal electrode layer (50) is 50 to 200 nm; Preferably, the material of the metal electrode layer (50) is selected from one or more of Ag, Au, Cu and Al.

9. The perovskite solar cell according to any one of claims 1 to 4, characterized in that The perovskite solar cell further comprises an interface modification layer (70), wherein the interface modification layer (70) is arranged between the electron transport layer (40) and the metal electrode layer (50).

10. The perovskite solar cell according to claim 9, characterized in that: The thickness of the interface modification layer (70) is 1 to 10 nm; Preferably, the material of the interface modification layer (70) is selected from one or more of BCP, MgO and LiF.

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