Ion migration inhibitor and trans-perovskite cell

Abstract

The invention relates to the technical field of photovoltaic cells, and provides an ion migration inhibitor and a trans-perovskite cell, the ion migration inhibitor comprises 4, 4 '-difluoro-2, 2'-dipyridyl, 4, 4 '-dichloro-2, 2'-dipyridyl, 4, 4 '-dibromo-2, 2'-dipyridyl or 4, 4 '-diiodo-2, 2'-dipyridyl, and the trans-perovskite cell is prepared from the trans-perovskite cell, the trans-perovskite cell and the 4, 4 '-difluoro-2, 2'-dipyridyl, the 4, 4 '-dichloro-2, 2'-dipyridyl or the 4, 4 '-diiodo-2, 2'-dipyridyl. The ion migration inhibitor is added into a hole blocking layer of a trans-perovskite battery, and the ion migration inhibitor is used for inhibiting migration and combination of metal cations and halogen anions. By using the ion migration inhibitor, the problems that non-conductive metal halide is formed by ion migration and combination of metal cations and halogen anions in an existing perovskite cell, a large number of defects are generated inside and on an interface of a perovskite film, so that non-radiation electron-hole recombination is accelerated, photogenerated charge loss is caused, and the efficiency of the perovskite cell is improved can be solved. And the stability of the device is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of photovoltaic cells, in particular to an ion migration inhibitor and an inverse perovskite cell. Background Art

[0002] Although the efficiency of perovskite solar cells is increasing year by year, their poor stability limits their commercial application. Under external environmental stimulation, the ion migration and chemical reaction between the metal electrode and the perovskite photosensitive layer in perovskite solar cells are one of the main reasons for the performance degradation of perovskite cells. The halogen anions in the perovskite layer will diffuse to the metal electrode, causing corrosion of the metal electrode and the loss of halides in the perovskite layer. Metals will also diffuse into the perovskite layer under photothermal conditions, forming non-conductive metal halides with halogen anions, and forming a large number of defect sites inside and at the interface of the perovskite film. These defects will accelerate non-radiative electron-hole recombination, resulting in photogenerated charge loss and reducing the photoelectric conversion efficiency and stability of the device. Summary of the invention

[0003] The purpose of the present invention is to solve the problem that the ion migration of metal cations and halogen anions in existing perovskite cells will combine to form non-conductive metal halides, generate a large number of defects inside and on the interface of the perovskite film, thereby accelerating non-radiative electron-hole recombination, leading to photogenerated charge loss, and reducing the stability of the device. An ion migration inhibitor and a trans-perovskite cell are provided.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] An ion migration inhibitor comprises 4,4'-difluoro-2,2'-bipyridine, 4,4'-dichloro-2,2'-bipyridine, 4,4'-dibromo-2,2'-bipyridine or 4,4'-diiodo-2,2'-bipyridine. The ion migration inhibitor is added to the hole blocking layer of an inverse perovskite battery and is used to inhibit the migration and combination of metal cations and halogen anions.

[0006] The present invention provides an ion migration inhibitor, which is added to the hole blocking layer of an inverse perovskite battery and contacts the metal electrode. The bipyridine heterocyclic structure in the ion migration inhibitor has a nitrogen atom coordination site, is Lewis basic, can combine with the metal cation to form a complex, and slows down the trend of the metal cation continuing to diffuse toward the perovskite layer. The halogen atoms on the ion migration inhibitor contain lone pairs of electrons that can repel halogen anions that diffuse toward the metal electrode, thereby reducing the mutual diffusion of metal cations and halogen anions, preventing the metal cations from combining with the halogen anions to form non-conductive metal halides, avoiding the formation of defect sites inside and on the surface of the perovskite film, reducing the non-radiative recombination of carriers, and thus improving the long-term stability of the perovskite battery.

[0007] An inverse perovskite cell comprises a substrate, a hole transport layer, a perovskite layer, an electron transport layer, a hole blocking layer and a metal electrode which are prepared in sequence, wherein the hole blocking layer comprises a hole blocking layer component and an ion migration inhibitor as described above.

[0008] The present invention provides a trans-perovskite battery, in which the ion migration inhibitor is added to the hole blocking layer, so as to inhibit the mutual diffusion of metal cations and halogen anions, slow down the corrosion of the metal electrode, avoid the formation of non-conductive metal halides, and improve the stability of the trans-perovskite battery.

[0009] As a preferred embodiment of the present invention, the hole blocking layer component comprises 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), and the thickness of the hole blocking layer is 5 to 10 nm.

[0010] As a preferred embodiment of the present invention, the mass ratio of the hole blocking layer component to the ion migration inhibitor is 10:1.

[0011] As a preferred embodiment of the present invention, the solvent of the ion migration inhibitor and the hole blocking layer component is isopropanol or ethanol.

[0012] As a preferred embodiment of the present invention, the component of the perovskite layer is FA 0.95 Cs 0.05 PbI 3 , the thickness of the perovskite layer is 500 to 900 nm.

[0013] As a preferred embodiment of the present invention, the hole transport layer comprises nickel oxide (NiO x), [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) or [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid (MeO-4PACZ).

[0014] As a preferred embodiment of the present invention, the electron transport layer comprises [6,6]-phenyl-C 71 -Methyl butyrate (PC 71 BM), the thickness of the electron transport layer is 25 to 50 nm.

[0015] As a preferred embodiment of the present invention, the material of the metal electrode is selected from one of silver, copper and aluminum, and the thickness of the metal electrode is 100 to 500 nm.

[0016] As a preferred embodiment of the present invention, the substrate comprises indium tin oxide (ITO) glass, fluorine-doped tin oxide (FTO) glass or aluminum-doped zinc oxide (AZO) glass.

[0017] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0018] 1. An ion migration inhibitor that can inhibit the mutual migration of metal cations and halogen anions, prevent the metal cations and halogen anions from combining to form non-conductive metal halides, avoid the formation of defect sites inside and on the surface of perovskite films, and reduce non-radiative recombination of carriers.

[0019] 2. In an inverse perovskite battery, an ion migration inhibitor is added to the hole blocking layer, which can inhibit the mutual diffusion of metal cations and halogen anions, slow down the corrosion of metal electrodes, avoid the formation of non-conductive metal halides, and improve the stability of the inverse perovskite battery. DETAILED DESCRIPTION

[0020] The present invention is described in detail below.

[0021] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail in the following examples. 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.

[0022] Example 1

[0023] An ion migration inhibitor used in the present invention comprises 4,4'-difluoro-2,2'-bipyridine, 4,4'-dichloro-2,2'-bipyridine, 4,4'-dibromo-2,2'-bipyridine or 4,4'-diiodo-2,2'-bipyridine. The ion migration inhibitor is added to the hole blocking layer of the inverse perovskite battery. The ion migration inhibitor is used to inhibit the migration and combination of metal cations and halogen anions.

[0024] The structural formulas of 4,4'-difluoro-2,2'-bipyridine, 4,4'-dichloro-2,2'-bipyridine, 4,4'-dibromo-2,2'-bipyridine and 4,4'-diiodo-2,2'-bipyridine are shown in Formula 1, Formula 2, Formula 3 and Formula 4 respectively:

[0025]

[0026] Example 2

[0027] An inverted perovskite cell used in the present invention comprises a substrate, a hole transport layer, a perovskite layer, an electron transport layer, a hole blocking layer and a metal electrode prepared in sequence, wherein the hole blocking layer comprises a hole blocking layer component and an ion migration inhibitor as described in Example 1.

[0028] Furthermore, the hole blocking layer component includes 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), and the thickness of the hole blocking layer is 5 to 10 nm.

[0029] Furthermore, the mass ratio of the hole blocking layer component to the ion migration inhibitor is 10:1.

[0030] Furthermore, the solvent of the ion migration inhibitor and the hole blocking layer component is isopropanol or ethanol.

[0031] Furthermore, the component of the perovskite layer is FA 0.95 Cs 0.05 PbI 3 , the thickness of the perovskite layer is 500 to 900 nm.

[0032] Furthermore, the hole transport layer comprises nickel oxide (NiO x ), [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) or [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid (MeO-4PACZ).

[0033] Furthermore, the electron transport layer comprises [6,6]-phenyl-C 71 -Methyl butyrate (PC 71 BM), the thickness of the electron transport layer is 25 to 50 nm.

[0034] Furthermore, the material of the metal electrode is selected from one of silver, copper and aluminum, and the thickness of the metal electrode is 100 to 500 nm.

[0035] Furthermore, the substrate comprises indium tin oxide (ITO) glass, fluorine-doped tin oxide (FTO) glass or aluminum-doped zinc oxide (AZO) glass.

[0036] In this embodiment, the substrate is made of fluorine-doped tin oxide (FTO) glass, and the substrate is ultrasonically cleaned with anhydrous ethanol for 20 minutes. After the substrate is fully dried in an oven, the substrate is treated with ultraviolet-ozone for 20 minutes; [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (Me-4PACZ) is spin-coated on the top surface of the substrate as the hole transport layer. A certain amount of FAI, PbI 2 , CsI, dissolved in a mixed solvent of dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) to prepare a perovskite precursor solution. The perovskite precursor solution was applied on the top surface of the hole transport layer by spin coating, and annealed at 100°C for 30 minutes to obtain the perovskite layer, the thickness of the perovskite layer being 600nm. The material of the electron transport layer in this embodiment is [6,6]-phenyl-C 71 -Methyl butyrate (PC 71 BM), the electron transport layer is prepared on the top surface of the perovskite layer by spin coating, and the thickness of the electron transport layer is 30nm. In this embodiment, 10mg of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) and 1mg of 4,4'-difluoro-2,2'-bipyridine are weighed and dissolved in 10ml of isopropanol solution, and stirred evenly to obtain a hole blocking layer solution.

[0037] Use a pipette to take 50 μl of the hole blocking layer solution and drop it onto the top surface of the electron transport layer. Set the spin coater to rotate at 2000-4000 rpm for 30 seconds. After the spin coating is completed, anneal at 80° C. for 10 minutes to obtain the hole blocking layer. In this embodiment, the material of the metal electrode is silver, which is prepared on the top surface of the hole blocking layer by vacuum evaporation. The prepared inverse perovskite cell is recorded as cell A.

[0038] Example 3

[0039] The present invention adopts a trans-perovskite battery, the structure of which is basically the same as that of Example 2, except that the ion migration inhibitor is 4,4'-dichloro-2,2'-bipyridine. The prepared battery is denoted as battery B.

[0040] Example 4

[0041] The present invention adopts a trans-perovskite battery, the structure of which is basically the same as that of Example 2, except that the ion migration inhibitor is 4,4'-dibromo-2,2'-bipyridine, and the prepared trans-perovskite battery is denoted as C battery.

[0042] Example 5

[0043] The present invention adopts a trans-perovskite battery, the structure of which is basically the same as that of Example 2, except that the ion migration inhibitor is 4,4'-diiodo-2,2'-bipyridine, and the prepared trans-perovskite battery is denoted as D battery.

[0044] Comparative Example

[0045] Its structure is basically the same as that of Example 2, except that 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) is used as a hole blocking layer. This inverse perovskite cell is recorded as a comparative cell.

[0046] Performance test: A simulated light source system was used to perform photovoltaic performance tests on the obtained inverse perovskite solar cells: cell A, cell B, cell C, cell D and comparison cell; the cells were aged for 1000 hours under test conditions of a temperature of 20-30°C and a humidity of 40-50%, and then a simulated light source system was used to perform a stability test. The photovoltaic performance results of cell A, cell B, cell C, cell D and comparison cell after aging were recorded as A1, B1, C1, D1 and comparison cell 1, respectively.

[0047] Table 1 Test results

[0048] Battery Voc(V) <![CDATA[Jsc(mA / cm 2 )]]> FF(%) PCE(%) A 1.12 24.46 79.47 21.77 A1 1.06 24.36 77.89 20.12 B 1.10 24.71 78.52 21.34 B1 1.05 24.32 76.17 19.45 C 1.11 24.68 79.53 21.79 C1 1.03 23.27 76.92 18.44 D 1.11 24.54 79.19 21.57 D1 1.02 23.14 73.15 17.27 Compare Batteries 1.10 24.77 78.58 21.41 Comparison battery 1 0.87 21.74 70.58 13.35

[0049] As can be seen from the table, the inverse perovskite solar cells prepared by using 4,4'-difluoro-2,2'-bipyridine, 4,4'-dichloro-2,2'-bipyridine, 4,4'-dibromo-2,2'-bipyridine and 4,4'-diiodo-2,2'-bipyridine as ion migration inhibitors added to the hole blocking layer respectively maintained 92%, 91%, 85% and 80% of the initial efficiency under the condition of continuous aging for 1000h; while the perovskite solar cell prepared by the hole blocking layer without adding ion migration inhibitors maintained 62% of the initial efficiency under the same conditions. Therefore, adding ion migration inhibitors to the hole blocking layer can effectively improve the stability of the inverse perovskite cell.

[0050] 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 protection scope of the present invention.

Claims

1. An ion migration inhibitor, characterized in that The invention comprises 4,4'-difluoro-2,2'-bipyridine, 4,4'-dichloro-2,2'-bipyridine, 4,4'-dibromo-2,2'-bipyridine or 4,4'-diiodo-2,2'-bipyridine. The ion migration inhibitor is added into the hole blocking layer of the inverse perovskite battery. The ion migration inhibitor is used for inhibiting the migration and combination of metal cations and halogen anions.

2. An inverse perovskite cell, comprising a substrate, a hole transport layer, a perovskite layer, an electron transport layer, a hole blocking layer and a metal electrode prepared in sequence, characterized in that: The hole blocking layer comprises a hole blocking layer component and an ion migration inhibitor as claimed in claim 1.

3. The inverse perovskite battery according to claim 2, characterized in that: The hole blocking layer component includes 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), and the thickness of the hole blocking layer is 5 to 10 nm.

4. The inverse perovskite battery according to claim 2, characterized in that: The mass ratio of the hole blocking layer component to the ion migration inhibitor is 10:

1.

5. The inverse perovskite cell according to claim 2, characterized in that: The solvent of the ion migration inhibitor and the hole blocking layer component is isopropyl alcohol or ethanol.

6. The inverse perovskite battery according to claim 2, characterized in that: The composition of the perovskite layer is FA 0.95 Cs 0.05 PbI3, the thickness of the perovskite layer is 500-900nm.

7. An inverse perovskite battery according to any one of claims 2 to 6, characterized in that: The hole transport layer comprises nickel oxide (NiO x ), [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) or [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid (MeO-4PACZ).

8. An inverse perovskite battery according to any one of claims 2 to 6, characterized in that: The electron transport layer comprises [6,6]-phenyl-C 71 -Methyl butyrate (PC 71 BM), the thickness of the electron transport layer is 25 to 50 nm.

9. An inverse perovskite battery according to any one of claims 2 to 6, characterized in that: The material of the metal electrode is selected from silver, copper and aluminum, and the thickness of the metal electrode is 100-500 nm.

10. An inverse perovskite battery according to any one of claims 3 to 6, characterized in that: The substrate comprises indium tin oxide (ITO) glass, fluorine-doped tin oxide (FTO) glass or aluminum-doped zinc oxide (AZO) glass.

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