Interface modification material, perovskite solar cell and preparation method thereof

Abstract

The application discloses an interface modification substance, an interface modifier, a perovskite thin film layer and a solar cell, wherein the interface modification substance has a structure as shown in formula 1: formula 1: wherein A1, A2 and A3 are each independently selected from alkyl with less than 6 carbon atoms, T is selected from F, Cl, Br, I, HSO4, and R contains a structure as shown in formula 2; formula 2: The interface modification substance of the application is used for interface modification of a perovskite solar cell, and improves the certified power conversion efficiency of the perovskite solar cell.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of perovskite solar cells, and in particular to an interface modification substance, a perovskite solar cell and a preparation method thereof. BACKGROUND

[0002] Perovskite materials have high absorption coefficient and charge carrier mobility, long carrier diffusion distance and adjustable band gap, and perovskite solar cells based on the materials have made great progress in power conversion efficiency compared with ordinary solar cells. Perovskite solar cells can achieve high certified power conversion efficiency.

[0003] However, perovskite solar cells also have stability problems such as ion migration, non-radiative recombination and decomposition of perovskite body. The hole transport layer in the perovskite solar cell mostly needs to be doped with an exogenous dopant with hygroscopic and volatile properties. In the doping process, there are problems such as limited repeatability and degradation of the perovskite layer during device operation, which affect the stability of the perovskite solar cell. Therefore, the application of undoped perovskite solar cells has gradually attracted attention. Although the stability of the undoped perovskite solar cell is better than that of the doped perovskite solar cell, the certified power conversion efficiency of the undoped perovskite solar cell is lower than that of the doped perovskite solar cell.

[0004] Moreover, the existing way of passivating the perovskite layer and the hole transport layer by using a straight-chain alkylammonium salt to improve the certified power conversion efficiency of the perovskite solar cell still has a significant gap compared with the certified power conversion efficiency of the doped perovskite solar cell. SUMMARY

[0005] The purpose of the present application is to provide an interface modification substance for a perovskite solar cell, which is used for interface modification of the perovskite solar cell and improves the certified power conversion efficiency of the perovskite solar cell.

[0006] The present application also provides a perovskite solar cell for improving the certified power conversion efficiency of the perovskite solar cell.

[0007] The purpose of the present application is achieved by the following technical solutions:

[0008] An interface modification substance for a perovskite solar cell, the interface modification substance has a structure as shown in Formula 1:

[0009] Formula 1: ,

[0010] wherein A1, A2 and A3 are each independently selected from an alkyl group with a carbon atom number less than 6, T is selected from F, Cl, Br, I and HSO4, R comprises a structure as shown in Formula 2, and the wavy line in Formula 2 is a bonding position.

[0011] Formula 2: .

[0012] In other words, the substance of the structure shown in Formula 1 can be used as an interface modification substance for perovskite solar cells, i.e. its use is as an interface modification substance for perovskite solar cells.

[0013] Preferably, A1, A2 and A3 are each independently selected from methyl, ethyl, propyl, isopropyl, A1, A2 and A3 being the same or different; and / or, the number of carbon atoms of R is less than 10, for example less than 8, less than 6 or less than 4.

[0014] Preferably, R is selected from one of the following groups:

[0015]

[0016] Preferably, the interface modification substance is selected from one of (2-methoxyethoxymethyl)trimethylammonium chloride, (2-methoxyethoxymethyl)triethylammonium chloride, ethyl[2-(2-methoxyethoxy)ethyl]-dimethylammonium chloride, ethyl[2-(2-ethoxyethoxy)ethyl]-dimethylammonium chloride.

[0017] The structural formula of (2-methoxyethoxymethyl)trimethylammonium chloride is: .

[0018] The structural formula of (2-methoxyethoxymethyl)triethylammonium chloride is: .

[0019] The structural formula of ethyl[2-(2-methoxyethoxy)ethyl]-dimethylammonium chloride is: .

[0020] The structural formula of ethyl[2-(2-ethoxyethoxy)ethyl]-dimethylammonium chloride is: .

[0021] An interface modifier, comprising:

[0022] The interface modification substance of any one of the above;

[0023] A solvent.

[0024] Preferably, the solvent is selected from anhydrous chloroform;

[0025] The molar concentration of the interface modification substance is 1.0-2.0 mmol / L.

[0026] A perovskite thin film layer, a surface of the perovskite thin film layer for facing a hole transport layer is modified using an interface modifier, the interface modifier being an interface modifier of any one of the above.

[0027] Preferably, the modification using the interface modifier comprises:

[0028] applying the interface modifier to a surface of the perovskite thin film layer for facing the hole transport layer;

[0029] annealing the perovskite thin film layer to obtain a modified perovskite thin film layer.

[0030] Preferably, the annealing temperature is 100-150℃, and the annealing time is 30-60s.

[0031] Preferably, the interface modifier is applied to the surface of the perovskite thin film layer for facing the hole transport layer by spin coating method, the spin coating speed is 1000-5000rpm, and the spin coating time is 10-30s.

[0032] A perovskite solar cell comprising the perovskite thin film layer of any one of the above.

[0033] Preferably, the perovskite solar cell further comprises:

[0034] a substrate;

[0035] an electron transport layer on the substrate, the perovskite thin film layer on the electron transport layer;

[0036] a hole transport layer on the perovskite thin film layer;

[0037] an electrode layer on the hole transport layer.

[0038] Preferably, the substrate is an FTO glass substrate.

[0039] Preferably, the material of the perovskite thin film layer comprises ABX3, wherein A is selected from at least one of CH3NH3 + , HC(NH2)2 + , Cs + and Rb + ; B is selected from Pb 2+ ; X is or a halogen ion mixture containing at least ; and / or,

[0040] the material of the hole transport layer is selected from any one of Spiro-OMeTAD, PEDOT:PSS, PTB7, PTAA or NiO.

[0041] Preferably, the material of the electron transport layer is selected from any one of SnO2, TiO2and a mixture of SnO2, Nb2O5, PC60BM and a mixture of TiO2and mesoporous TiO2.

[0042] Preferably, the material of the electrode layer is selected from a metal electrode, a carbon-based electrode or other conductive electrode.

[0043] A method for preparing any of the above perovskite solar cells, comprising:

[0044] providing a substrate;

[0045] forming an electron transport layer on the substrate;

[0046] forming a perovskite thin film layer on the electron transport layer;

[0047] forming a hole transport layer on the perovskite thin film layer;

[0048] forming an electrode layer on the hole transport layer.

[0049] Compared with the prior art, the beneficial effects of the present application at least include:

[0050] By using the interface modifier composed of the interface modification material of the present application to modify the surface of the perovskite thin film layer towards the hole transport layer, the ammonium salt containing the structure of formula 2 in the interface modifier can be used as a surface passivation agent to achieve the modification of the interface between the perovskite layer and the hole transport layer, optimize the effective charge extraction in the perovskite solar cell and inhibit the interface recombination, and improve the certified power conversion efficiency of the perovskite solar cell; wherein the lone pair of electrons of the oxygen in the structure of formula 2 in the interface modifier can also produce additional passivation effect, further improving the certified power conversion efficiency of the perovskite solar cell. BRIEF DESCRIPTION OF DRAWINGS

[0051] Figure 1 is a structural schematic diagram of a perovskite solar cell of an embodiment of the present application.

[0052] In the figure: 1, substrate; 2, electron transport layer; 3, perovskite thin film layer; 4, interface modifier; 5, hole transport layer; 6, electrode layer. DETAILED DESCRIPTION

[0053] Example implementations will now be described more fully with reference to the accompanying drawings. Example implementations, however, can be implemented in many different forms and should not be construed as limited to the implementations set forth herein; rather, these implementations are provided so that this disclosure will be thorough and complete, and fully convey the inventive aspects to those skilled in the art. Like reference numerals can be used to refer to like elements throughout.

[0054] The interface modification materials in the examples and comparative examples are prepared by known methods, and octyltrimethylammonium chloride (CAS: 10108-86-8) can be commercially available, and the known methods include the methods in the following patents or literatures:

[0055] JP4790255B2, CN107072913A, CN106715407A.

[0056] A new general method for protection of the hydroxyl function, E. J. Corey , Jean-Louis Gras, Peter Ulrich, Tetrahedron Letters, Volume 17, Issue 11, March 1976, Pages 809-812. Example 1

[0057] Reference Figure 1 A perovskite solar cell is prepared by the following method:

[0058] Preparation of perovskite precursor solution: PbI2, FAI (formamidinium iodide), MABr (methylammonium bromide), PbBr2 are dissolved in DMF (N,N-Dimethylformamide) and DMSO (Dimethyl sulfoxide) in a molar ratio of 0.992:0.992:0.008:0.008, and heated at 70°C for 1 hour under continuous stirring to make it completely dissolved, to obtain a (FA 0.992 MA 0.008 Pb(I 0.992 Br 0.008 )3) perovskite precursor solution with a concentration of 1.0 mol / L.

[0059] Substrate 1 treatment: the FTO glass (fluorine-doped SnO2 conductive glass) substrate 1 is ultrasonically cleaned with acetone and isopropyl alcohol (IPA); a 0.1 mol / L SnCl2•2H2O solution dissolved in deionized water is coated on the FTO glass substrate 1 at a spin rate of 3000 rpm for 30 s to form a SnO2 electron transport layer 2 (ETLs) on the FTO glass substrate 1, and the FTO glass substrate 1 and the SnO2 electron transport layer 2 together form a cell substrate; then the cell substrate is annealed at 100°C for 10 minutes in an air atmosphere, and after the temperature drops to room temperature, the cell substrate is transferred to a glove box, and the cell substrate is treated with a UV ozone surface cleaning agent for 15 minutes.

[0060] Preparation of perovskite thin film layer 3: (FA 0.992 MA 0.008 Pb(I 0.992 Br0.008 )3) The perovskite precursor solution is spin-coated on the above-mentioned cell substrate, the spin-coating speed is 500 rpm, the spin-coating time is 5 s, then the spin-coating speed is 1200 rpm for 3 s, and finally the spin-coating speed is 5000 rpm for 12 s; during the last step of coating, 1 ml of diethyl ether is dripped onto the rotating film formed on the surface of the cell substrate during the spin-coating process, and then the product is annealed at 100°C for 1 hour to form the perovskite thin film layer 3.

[0061] Interface modification of the perovskite thin film layer 3: (2-methoxyethoxymethyl) trimethylammonium chloride is used as the interface modifier. The (2-ethoxyethoxymethyl) trimethylammonium chloride is dissolved in anhydrous chloroform to prepare a 1 mmol / L interface modifier solution, which is interface modifier 4. The interface modifier 4 is spin-coated on the surface of the perovskite thin film layer 3 facing the hole transport layer 5 by spin-coating, the spin-coating speed is 5000 rpm, and the spin-coating time is 10 s; after the spin-coating is completed, the product is annealed at a temperature of 150°C for 30 s to complete the interface modification of the perovskite thin film layer 3.

[0062] Preparation of the hole transport layer 5 solution: 100 mg of Spiro-OMeTAD (2,2',7,7'-Tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene, 2,2',7,7'-tetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene) is added to a mixed solvent of chlorobenzene and diphenyl ether, and mixed uniformly to prepare a Spiro-OMeTAD solution with a concentration of 100 mg / ml. Among them, the volume ratio of chlorobenzene to diphenyl ether in the mixed solvent of chlorobenzene and diphenyl ether is 97:3.

[0063] Preparation of the hole transport layer 5: the Spiro-OMeTAD solution is spin-coated on the surface of the perovskite thin film layer 3 which has been interface modified, the spin-coating speed of the Spiro-OMeTAD solution is 2000 rpm, the spin-coating time is 30 s, and after the spin-coating is completed, the product is annealed at 100°C for 5 min to form the hole transport layer 5.

[0064] Preparation of the electrode layer 6: a gold electrode layer 6 is evaporated on the hole transport layer 5 using a thermal evaporation method to prepare a perovskite solar cell, and the cell is named A.

[0065] The above preparation processes are all carried out in an atmosphere with a humidity of 10-15%, and in the prepared perovskite solar cell, the thickness of the electron transport layer 2 is 40 nm, the thickness of the perovskite thin film layer 3 is 400 nm, the thickness of the hole transport layer 5 is 100 nm, and the thickness of the gold electrode layer 6 is 80 nm. Example 2

[0066] Referring to Figure 1 A perovskite solar cell is prepared by the following method:

[0067] In the perovskite solar cell of the present embodiment, the substrate 1, the electron transport layer 2, the perovskite thin film layer 3, and the interface modification method of the perovskite thin film layer 3 are all the same as those of Embodiment 1, and thus are not described here.

[0068] The hole transport layer 5 and the electrode layer 6 are prepared by the following method:

[0069] 100 mg of Spiro-OMeTAD is added to chlorobenzene doped with 23 μL of Li-TFSI (Lithium Bis(trifluoromethanesulphonyl)imide), 10 μL of FK209 (Tris[4-(1,1-dimethylethyl)-2-(1H-pyrazol-1-yl)pyridine]cobalt salt with 1,1,1-trifluoro-N-[(trifluoromethyl)sulfonyl]methanesulfonamide (1:3)), and 39 μL of 4-tBP (4-tert-Butylpyridine), and is mixed uniformly to prepare a Spiro-OMeTAD solution with a concentration of 100 mg / mL. The volume of chlorobenzene is 1.1 ml.

[0070] The Spiro-OMeTAD solution is spin-coated on the surface of the perovskite thin film layer 3 which is modified, the spin-coating speed of the Spiro-OMeTAD solution is 2000 rpm, the spin-coating time is 30 s, and after the spin-coating is completed, the product is annealed at 100°C for 5 min to form the hole transport layer 5. The hole transport layer 5 is a doped hole transport layer.

[0071] The gold electrode layer 6 is evaporated on the hole transport layer 5 using a thermal evaporation method to prepare a doped perovskite solar cell, and the prepared cell is named as B.

[0072] The above preparation processes are all carried out in an atmosphere with a humidity of 10-15%. Embodiment 3

[0073] A perovskite solar cell is prepared by the following method:

[0074] The interface modification material in Example 1 is replaced by (2- methoxyethyloxyethyl)trimethylammonium chloride, and a battery is prepared and named as C. Example 4

[0075] Referring to Figure 1 A perovskite solar cell is prepared by the same method as in Example 1, except that:

[0076] The interface modification material in Example 1 is replaced by ethyl [2- (2- methoxyethyloxy) ethyl] -dimethylammonium chloride, and a battery is prepared and named as D. Example 5

[0077] Referring to Figure 1 A perovskite solar cell is prepared by the same method as in Example 1, except that:

[0078] The interface modification material in Example 1 is replaced by ethyl [2- (2- methoxyethyloxy) ethyl] -dimethylammonium chloride, and a battery is prepared and named as D. Comparative Example 1

[0079] A perovskite solar cell is prepared by the following method:

[0080] Preparation of perovskite precursor solution: same as in Example 1.

[0081] Treatment of substrate 1: same as in Example 1.

[0082] Preparation of perovskite thin film layer 3: same as in Example 1.

[0083] Preparation of hole transport layer 5 solution: same as in Example 1.

[0084] Preparation of hole transport layer 5: the Spiro-OMeTAD solution is spin-coated on the surface of the perovskite thin film which is not modified, the spin-coating speed of the Spiro-OMeTAD solution is 2000 rpm, the spin-coating time is 30 s, and after spin-coating, the product is annealed at 100°C for 5 min to form the hole transport layer 5.

[0085] Preparation of electrode layer 6: same as in Example 1, and a battery is prepared and named as F.

[0086] The above preparation processes are all carried out in an atmosphere with a humidity of 10-15%. Comparative Example 2

[0087] The perovskite solar cell of the present example is the same as Comparative Example 1 in the base 1, the electron transport layer 2, the perovskite thin film layer 3, and the electrode layer 6, and thus will not be repeated here.

[0088] The hole transport layer 5 is the same as that of Example 2.

[0089] The doped perovskite solar cell is prepared and named G.

[0090] The above preparation processes are all carried out in an atmosphere with a humidity of 10-15%. Comparative Example 3

[0091] The perovskite solar cell of the present example is the same as Comparative Example 1 in the base 1, the electron transport layer 2, the perovskite thin film layer 3, and the electrode layer 6, and thus will not be repeated here.

[0092] In addition, it further comprises the following steps:

[0093] Perovskite thin film layer 3 interface modification: octyltrimethylammonium chloride is used as the interface modification material, and the octyltrimethylammonium chloride is dissolved in anhydrous chloroform to prepare a 1 mmol / L interface modifier solution. The interface modifier solution is spin-coated on the surface of the perovskite thin film layer 3 facing the hole transport layer 5 by spin coating method, the spin coating time is 5000 rpm, and the spin coating time is 10 s; after spin coating, the product is annealed at a temperature of 150°C, and the annealing time is 30 s, so as to complete the interface modification of the perovskite thin film layer 3.

[0094] Preparation of hole transport layer 5 solution: same as Example 2.

[0095] Preparation of hole transport layer 5: same as Example 2.

[0096] Preparation of electrode layer 6: same as Example 2, and the prepared cell is named H.

[0097] The above preparation processes are all carried out in an atmosphere with a humidity of 10-15%.

[0098] The perovskite solar cells prepared in each of the above examples and comparative examples are measured under 1 sun light (100 mW / cm 2 , AM1.5G), and the Jsc, Voc, and FF values of the perovskite solar cells are measured in an air environment to obtain the following table data:

[0099]

[0100] PCE = Voc Jsc FF / Pin wherein PCE is the certified power conversion efficiency; PCEavg is the average of PCEs of the forward and reverse scans; Jsc is the operating current per unit light-receiving area of the solar cell under short-circuit conditions, i.e., short-circuit current density; Voc is the output voltage of the solar cell under open-circuit conditions, i.e., open-circuit voltage; and FF is the ratio of the maximum output power Pmax per unit light-receiving area to Jsc x Voc, also referred to as the fill factor. PCE can be calculated by the following formula: PCE = Voc Jsc FF / Pin. Pin is the incident power of sunlight, and under 1 sun light conditions, Pin is 100 mW / cm2 2 .

[0101] Example 1, 3, 4, 5 are perovskite solar cells with undoped hole transport layer 5, and the perovskite solar cells of Example 1, 3, 4, 5 are modified by the interface modifier 4 of the present application; Example 2 is a perovskite solar cell with a doped hole transport layer 5, and the perovskite solar cell of Example 2 is modified by the interface modifier 4 of the present application; Comparative Example 1 is a perovskite solar cell with an undoped hole transport layer 5, and Comparative Example 1 is not modified by the interface modifier 4 of the present application; Comparative Example 2 is a perovskite solar cell with a doped hole transport layer 5, and Comparative Example 2 is not modified by the interface modifier 4 of the present application. Comparative Example 3 is a perovskite solar cell with a doped hole transport layer 5, and Comparative Example 3 uses an interface modifier including a straight-chain alkyl ammonium salt to passivate the perovskite thin film layer 3 and the hole transport layer 5.

[0102] It can be seen that, compared with the existing undoped perovskite solar cell, i.e. the hole transport layer 5 of the perovskite solar cell is an undoped hole transport layer, such as Comparative Example 1; the PETavg of the undoped perovskite solar cell which is interface modified by the interface modifier 4 of the present application is significantly improved; and, compared with the existing doped perovskite solar cell, i.e. the hole transport layer 5 of the perovskite solar cell is a doped hole transport layer, such as Comparative Example 2; the PETavg of the undoped perovskite solar cell which is interface modified by the interface modifier 4 of the present application is also similar to that of the doped perovskite solar cell, so that the undoped perovskite solar cell of the present application can have a certification power conversion efficiency similar to that of the doped perovskite solar cell, and can avoid the problems of limited repeatability and degradation of the perovskite layer during device operation when the doped hole transport layer 5 exists, i.e. can retain the high stability of the undoped perovskite solar cell compared with the doped perovskite solar cell. For the doped perovskite solar cell, compared with the perovskite solar cell using a straight-chain alkylammonium salt as an interface modifier, such as Comparative Example 3; the PCEavg of the perovskite solar cell which is interface modified by the interface modifier 4 of the present application is relatively superior, i.e. the perovskite solar cell which is interface modified by the interface modifier 4 of the present application has a higher certification power conversion efficiency compared with the perovskite solar cell using a straight-chain alkylammonium salt as an interface modifier.

[0103] Therefore, interface modification of the perovskite solar cell by the interface modifier 4 of the present application can effectively improve the certification power conversion efficiency of the perovskite solar cell; and the interface modifier 4 of the present application has a better effect on improving the certification power conversion efficiency of the perovskite solar cell compared with the interface modifier comprising a straight-chain alkylammonium salt.

[0104] Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting the present application, and those of ordinary skill in the art can make changes, modifications, replacements and variations to the above embodiments without departing from the principles and spirit of the present application within the scope of the present application, and all such changes should be within the protection scope of the claims of the present application.

Claims

1. An interfacial modifier characterized in that, The interface modification material and a solvent are included; the molar concentration of the interface modification material is 1.0-2.0 mmol / L; the interface modification material has a structure as shown in Formula 1: Formula 1: , wherein A1, A2 and A3 are each independently selected from an alkyl group with less than 6 carbon atoms, T is selected from F, Cl, Br, I, HSO4, and R is selected from one of the following groups: the solvent is selected from the group consisting of anhydrous chloroform.

2. The interface modifier of claim 1, wherein, A1, A2 and A3 are each independently selected from methyl, ethyl, propyl, isopropyl, and A1, A2 and A3 are the same or different.

3. The interface modifier of claim 1, wherein, The interface modification material is selected from one of (2-methoxyethoxymethyl)trimethylammonium chloride, (2-methoxyethoxymethyl)triethylammonium chloride, ethyl[2-(2-methoxyethoxy)ethyl]-dimethylammonium chloride, and ethyl[2-(2-ethoxyethoxy)ethyl]-dimethylammonium chloride.

4. A perovskite thin film layer, characterized by, The surface of the perovskite thin film layer for facing the hole transport layer is modified using an interface modifier, and the interface modifier is as described in any one of claims 1-3.

5. The perovskite thin film layer of claim 4, wherein The modification using the interface modifier includes: applying the interface modifier to the surface of the perovskite thin film layer for facing the hole transport layer; annealing the perovskite thin film layer to obtain a modified perovskite thin film layer.

6. The perovskite thin film layer of claim 5, wherein The annealing temperature is 100-150°C, and the annealing time is 30-60s.

7. A perovskite solar cell, characterized by, The perovskite thin film layer as described in any one of claims 4-6 is included.

8. The perovskite solar cell according to claim 7, characterized in that, Further included are: a substrate; an electron transport layer on the substrate, the perovskite thin film layer on the electron transport layer; a hole transport layer on the perovskite thin film layer; an electrode layer on the hole transport layer.

9. The perovskite solar cell according to claim 8, characterized in that, The material of the perovskite thin film layer comprises ABX3, wherein A is selected from at least one of CH3NH3 + , HC(NH2)2 + , Cs + , and Rb + ; B is selected from Pb 2+ ; X is or a halogen ion mixture containing at least ​ The material of the hole transport layer is selected from any one of Spiro-OMeTAD, PEDOT:PSS, PTB7, PTAA or NiO.

10. A method for preparing a perovskite solar cell as described in claim 8, characterized in that, The method includes: providing a substrate; forming an electron transport layer on the substrate; forming a perovskite thin film layer on the electron transport layer; forming a hole transport layer on the perovskite thin film layer; forming an electrode layer on the hole transport layer.

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