Preparation method of electron transport layer and perovskite cell

Abstract

The invention relates to the technical field of photovoltaic cells, and provides a preparation method of an electron transport layer and a perovskite cell, and the preparation method of the electron transport layer comprises the following steps: preparing an electron transport layer solution, and preparing an electron transport material and a solvent into a mixed solution; coating the top surface of a perovskite layer with the mixed solution, and performing film forming treatment and annealing treatment to obtain an electron transport layer; the electron transmission layer can transmit electrons and passivate surface defects of the perovskite layer; the electron transport material comprises amino-modified fullerene or a derivative thereof. By using the method, the problem that the perovskite cell has relatively large open voltage loss due to severe non-radiative recombination between the perovskite layer and the electron transport layer interface when the current common electron transport material is used as the electron transport layer of the broadband gap perovskite solar cell can be solved.

Description

Technical Field

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

[0002] Inverse perovskite solar cells (IPSCs) have attracted widespread attention in recent years due to their advantages, including simple fabrication, low-temperature film formation, low hysteresis, and suitability for combining with conventional solar cells to create stacked devices. In inverse perovskite solar cells, fullerenes are widely used as electron transport materials (ETMs) due to their unique electrical properties and high chemical capacitance.

[0003] In inverse perovskite cells, fullerene is used as the electron transport layer material, and its performance has an important impact on the overall efficiency and stability of the cell. Commonly used fullerene materials are C 60 and PC 61 BM, however, since the conduction band minimum of perovskite is close to C 60 The small energy level shift between the lowest unoccupied molecular orbital (LUMO) energy level or the charge transfer state at the interface, C 60 Due to the lack of functionalization, PC cannot react with perovskite to passivate, which restricts the further improvement of perovskite battery efficiency. 61 BM has great potential in electron mobility, complexity of forming high-quality thin films, and in perovskite / PC 61 There are limitations in the non-radiative recombination at the BM interface. These limitations lead to lower efficiencies of inverse perovskite solar cells compared to cells with regular structures.

[0004] C 60 and PC 61 When BM is used as an electron transport layer, there are interface non-radiative recombination defects. To overcome these defects, researchers are constantly exploring new interface layer materials and improvement strategies to improve the performance and stability of perovskite solar cells. Summary of the Invention

[0005] The purpose of the present invention is to solve the problem that when currently common electron transport materials are used as the electron transport layer of a wide-bandgap perovskite solar cell, serious non-radiative recombination occurs at the interface between the perovskite layer and the electron transport layer, resulting in a large open-circuit voltage loss in the perovskite cell. A method for preparing an electron transport layer and a perovskite cell are provided. An amino-modified fullerene derivative is used. Compared with an electron transport layer made directly from fullerene, the N atom in the amino functional group contains a lone pair of electrons and exhibits Lewis basicity. It can combine with uncoordinated lead cations at the interface of the perovskite layer to form a complex, thereby reducing interface defects, reducing non-radiative recombination losses, and improving the open-circuit voltage of the perovskite cell.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A method for preparing an electron transport layer comprises the following steps: preparing an electron transport layer solution, configuring an electron transport material and a solvent into a mixed solution; applying the mixed solution on the top surface of a perovskite layer, and then obtaining an electron transport layer through film formation and annealing; the electron transport layer is capable of transporting electrons and passivating surface defects of the perovskite layer; the electron transport material comprises an amino-modified fullerene or a derivative thereof.

[0008] As a preparation method of an electron transport layer provided by the present invention, the electron transport layer currently made of fullerene has serious non-radiative recombination defects at the interface between the perovskite layer and the electron transport layer; the electron transport layer prepared by the preparation method provided by the present invention uses an amino-modified fullerene derivative. Compared with the electron transport layer directly made of fullerene, the N atom in the amino functional group contains a lone pair of electrons and exhibits Lewis basicity, which can combine with the uncoordinated lead cations at the interface of the perovskite layer to form a complex, thereby reducing interface defects and reducing non-radiative recombination losses.

[0009] As a preferred embodiment of the present invention, the electron transport material comprises 3-diethylaminopropylamine fullerene, N,N-diethylethylenediamine fullerene, N,N-diethyl-1,4-phenylenediamine fullerene, 3-dimethylaminopropylamine fullerene or N,N-dimethylethylenediamine fullerene.

[0010] As a preferred embodiment of the present invention, the molar ratio of the electron transport material to the solvent is.

[0011] As a preferred embodiment of the present invention, the concentration of the electron transport material in the mixed solution is 1 to 40 mg / mL, preferably 10 to 25 mg / mL.

[0012] As a preferred embodiment of the present invention, the solvent comprises chlorobenzene, isopropyl alcohol or anisole.

[0013] As a preferred embodiment of the present invention, the film forming process comprises blade coating, spin coating or slit coating.

[0014] As a preferred embodiment of the present invention, the annealing temperature of the annealing treatment is 50-120° C., and the annealing time is 5-20 minutes.

[0015] A perovskite battery comprises a substrate, a hole transport layer, a perovskite layer, an electron transport layer prepared by the above-mentioned electron transport preparation method, and a metal electrode stacked in sequence.

[0016] The present invention adopts a perovskite cell, which uses an amino-modified fullerene derivative to reduce interface defects and non-radiative recombination losses between the electron transport layer and the perovskite layer, thereby improving the photoelectric conversion efficiency of the perovskite cell.

[0017] As a preferred embodiment of the present invention, the invention further comprises a hole blocking layer, wherein the material of the hole blocking layer is 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), and the thickness of the hole blocking layer is 2 to 20 nm.

[0018] As a preferred embodiment of the present invention, the perovskite layer comprises a two-dimensional perovskite layer or a three-dimensional perovskite layer.

[0019] As a preferred embodiment of the present invention, the hole transport layer comprises nickel oxide (NiO x ), 3-hexylthiophene (P3HT), cuprous thiocyanate (CuSCN), [2-(9h-carbazole-9-yl)ethyl]phosphonic acid (2PACz), [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (MeO-2PACz), [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (Me-4PACz) and [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid (MeO-4PACz).

[0020] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0021] A method for preparing an electron transport layer uses an amino-modified fullerene derivative. Compared with an electron transport layer made directly from fullerene, the nitrogen atom in the amino functional group contains a lone pair of electrons, exhibits Lewis basicity, and can combine with uncoordinated lead cations at the interface of the perovskite layer to form a complex, thereby reducing interface defects and minimizing non-radiative recombination losses.

[0022] A perovskite cell uses an amino-modified fullerene derivative to reduce interface defects and non-radiative recombination losses between the electron transport layer and the perovskite layer, thereby improving the photoelectric conversion efficiency of the perovskite cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is the JV curve diagram of battery A and battery B;

[0024] Figure 2 These are the PL test diagrams of battery A and battery B. DETAILED DESCRIPTION

[0025] The present invention will be described in detail below with reference to the accompanying drawings.

[0026] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. 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.

[0027] Example 1

[0028] The present invention provides a method for preparing an electron transport layer, comprising the following steps: preparing an electron transport layer solution, preparing an electron transport material and a solvent into a mixed solution; applying the mixed solution on the top surface of a perovskite layer, and then obtaining an electron transport layer through film formation and annealing; the electron transport layer is capable of transporting electrons and passivating surface defects of the perovskite layer; the electron transport material comprises an amino-modified fullerene or a derivative thereof.

[0029] Furthermore, the electron transport material comprises 3-diethylaminopropylamine fullerene, N,N-diethylethylenediamine fullerene, N,N-diethyl-1,4-phenylenediamine fullerene, 3-dimethylaminopropylamine fullerene or N,N-dimethylethylenediamine fullerene.

[0030] Furthermore, the structural formulas of 3-diethylaminopropylamine fullerene, N,N-diethylethylenediamine fullerene, N,N-diethyl-1,4-phenylenediamine fullerene, 3-dimethylaminopropylamine fullerene and N,N-dimethylethylenediamine fullerene are shown in Formula 1), Formula 2), Formula 3), Formula 4) and Formula 5), ​​respectively:

[0031]

[0032] Furthermore, the concentration of the electron transport material in the mixed solution is 1 to 40 mg / mL, preferably 10 to 25 mg / mL.

[0033] Furthermore, the solvent comprises chlorobenzene, isopropyl alcohol or anisole.

[0034] Furthermore, the film forming process includes blade coating, spin coating or slit coating.

[0035] Furthermore, the annealing temperature of the annealing treatment is 50-120° C., and the annealing time is 5-20 minutes.

[0036] Compared with the electron transport layer made directly from fullerene, the electron transport layer made from amino-modified fullerene or its derivatives as the electron transport material has a nitrogen atom in the amino functional group containing a lone pair of electrons, exhibiting Lewis basicity, and can combine with uncoordinated lead cations at the interface of the perovskite layer to form a complex, thereby reducing interface defects and reducing non-radiative recombination losses.

[0037] In this embodiment, the mixed solution was first prepared by dissolving 20 mg of 3-diethylaminopropylamine fullerene in 2 ml of chlorobenzene. The solution was placed on a stirring table, the stirring speed of the stirring table was adjusted to 600 rpm / s, and the mixture was stirred at room temperature for 6 hours to obtain the mixed solution.

[0038] The mixed solution is coated using a spin coating process. The substrate covered with the perovskite layer is transferred to a spin coater. Then, a pipette is used to drop the prepared mixed solution onto the perovskite layer. The solution is spin-coated at a speed of 2000 to 4000 rpm for 30 seconds, and finally annealed at 80°C for 10 minutes to obtain the electron transport layer.

[0039] Example 2

[0040] A perovskite cell used in the present invention comprises a substrate, a hole transport layer, a perovskite layer, an electron transport layer prepared by the electron transport preparation method described in Example 1, and a metal electrode stacked in sequence.

[0041] Furthermore, the invention further comprises a hole blocking layer, wherein the material of the hole blocking layer is 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), and the thickness of the hole blocking layer is 2 to 20 nm.

[0042] Furthermore, the perovskite layer includes a two-dimensional perovskite layer or a three-dimensional perovskite layer.

[0043] Furthermore, the hole transport layer comprises nickel oxide (NiO x ), 3-hexylthiophene (P3HT), cuprous thiocyanate (CuSCN), [2-(9h-carbazole-9-yl)ethyl]phosphonic acid (2PACz), [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (MeO-2PACz), [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (Me-4PACz) and [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid (MeO-4PACz).

[0044] The use of amino-modified fullerene derivatives reduces the interface defects and non-radiative recombination losses between the electron transport layer and the perovskite layer, thereby improving the photoelectric conversion efficiency of perovskite cells.

[0045] In this example, an inverse perovskite cell is used as an example. The specific preparation method is as follows: Preparation of the substrate: In this example, the substrate is indium tin oxide conductive glass (ITO). The substrate is ultrasonically cleaned with anhydrous ethanol, fully dried, and then subjected to UV-ozone treatment for 20 minutes.

[0046] Prepare the hole transport layer: weigh 2 mg of [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphoric acid (MeO-4PACz) and dissolve it in 4 ml of anhydrous ethanol. Stir until [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphoric acid (MeO-4PACz) is dissolved, and prepare a hole transport layer on the top surface of the substrate by spin coating.

[0047] Preparation of the perovskite photosensitive layer: Preparation of perovskite precursor solution. In this embodiment, a certain amount of FAI, PbI2, PbCl2, MABr, CsI, PbBr2 and MACl were weighed and dissolved in a mixed solvent of dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) to prepare a CsI solution with a concentration of 1.4 mol / L. 0.05 MA 0.18 FA 0.77 Pb(Br 0.2 I 0.8 )3+5% MAPbCl3 perovskite precursor solution. The annealing temperature of the perovskite photosensitive layer is 100° C., and the annealing time is 20 min. The thickness of the prepared perovskite photosensitive layer is 450 nm.

[0048] The electron transport layer and the hole blocking layer are prepared. The electron transport layer is prepared by the preparation method in Example 1, and the thickness of the electron transport layer is 20 nm; the material of the hole blocking layer is 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), and the thickness of the hole blocking layer is 6 nm.

[0049] The metal electrode layer was prepared. In this embodiment, the metal electrode was made of silver and had a thickness of 200 nm. The prepared battery was designated as Battery B.

[0050] Comparative Example 1

[0051] A perovskite battery, which is basically the same as Example 2, except that the electron transport layer is C 60 , recorded as battery A.

[0052] like Figure 1 As shown, at a temperature of 25°C, 100mW / cm 2 Under the condition of strong light, the JV curves of battery A and battery B were tested. Compared with the control group device, the perovskite cell using amino-modified fullerene derivatives as the electron transport material improved the open circuit voltage and fill factor of the solar cell device, and significantly improved the photoelectric efficiency of the perovskite cell.

[0053] like Figure 2As shown, PL tests were performed on battery A and battery B. Compared with battery A, battery B had higher peak intensity and fewer interface defects, reduced non-radiative recombination of carriers, and reduced opening voltage loss. Therefore, the use of amino-modified fullerene derivatives as the electron transport material can reduce the internal defects of the perovskite cell and improve the photoelectric conversion efficiency of the perovskite cell.

[0054] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing an electron transport layer, characterized in that: The method comprises the following steps: preparing an electron transport layer solution, and preparing an electron transport material and a solvent into a mixed solution; The mixed solution is coated on the top surface of the perovskite layer, and then an electron transport layer is obtained through film formation and annealing treatment; the electron transport layer can transport electrons and passivate surface defects of the perovskite layer; the electron transport material contains an amino-modified fullerene derivative.

2. The method for preparing an electron transport layer according to claim 1, wherein: The electron transport material comprises 3-diethylaminopropylamine fullerene, N,N-diethylethylenediamine fullerene, N,N-diethyl-1,4-phenylenediamine fullerene, 3-dimethylaminopropylamine fullerene or N,N-dimethylethylenediamine fullerene.

3. The method for preparing an electron transport layer according to claim 1, wherein: The concentration of the electron transport material in the mixed solution is 1 to 40 mg / mL, preferably 10 to 25 mg / mL.

4. The method for preparing an electron transport layer according to claim 1, wherein: The solvent includes chlorobenzene, isopropyl alcohol or anisole.

5. The method for preparing an electron transport layer according to any one of claims 1 to 4, characterized in that: The film forming process includes blade coating, spin coating or slit coating.

6. The method for preparing an electron transport layer according to any one of claims 1 to 4, characterized in that: The annealing temperature of the annealing treatment is 50-120° C., and the annealing time is 5-20 minutes.

7. A perovskite battery, characterized in that: The invention comprises a substrate, a hole transport layer, a perovskite layer, an electron transport layer prepared by the electron transport preparation method according to any one of claims 1 to 6, and a metal electrode stacked in sequence.

8. The perovskite battery according to claim 7, characterized in that: The invention also comprises a hole blocking layer, wherein the material of the hole blocking layer is 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), and the thickness of the hole blocking layer is 2-20 nm.

9. The method according to claim 7, characterized in that: The perovskite layer includes a two-dimensional perovskite layer or a three-dimensional perovskite layer.

10. The method according to claim 7, characterized in that: The hole transport layer comprises nickel oxide (NiO x ), 3-hexylthiophene (P3HT), cuprous thiocyanate (CuSCN), [2-(9h-carbazole-9-yl)ethyl]phosphonic acid (2PACz), [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (MeO-2PACz), [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (Me-4PACz) and [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid (MeO-4PACz).

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