SAM layer with surfactant and trans-perovskite cell

Abstract

The invention relates to the technical field of photovoltaic cells, and provides an SAM layer with a surfactant and a trans-perovskite cell, the self-assembly molecular layer with the surfactant comprises self-assembly molecules and the surfactant, the molecular formula of the surfactant comprises (CH3) 2C (CH2) nXNH2 or (CH3) 3C (CH2) nXNH2, n is greater than or equal to 1, X is Cl <->, Br <-> or I <->, and n is greater than or equal to 1. The surface active agent is dispersed among the self-assembly molecules or the surface active agent and the self-assembly molecules are stacked in a layered manner, and the surface active agent is used for inhibiting agglomeration of the self-assembly molecules and modifying a perovskite layer. By using the SAM layer, the problems that clusters among self-assembled molecules can cause non-uniform surface morphology of the SAM layer, then the growth and covering quality of a subsequent perovskite layer are influenced, more holes are formed in the bottom interface of the perovskite layer, the quality of a thin film becomes poor and the like can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic cells, in particular to a SAM layer with a surfactant and an inverse perovskite cell. Background Art

[0002] In inverse perovskite solar cells, the SAM layer (self-assembled monolayer) is used as a hole extraction layer to improve the efficiency and stability of the device. However, when the self-assembled molecules are adsorbed on a substrate (such as ITO), they tend to aggregate and form clusters due to the interaction between molecules, which is not conducive to the contact of the device interface and thus affects the performance of the device. In addition, the SAM layer often does not have good hydrophilicity, making it difficult to prepare a uniform perovskite film on the top surface of the SAM layer. The perovskite layer is also prone to unevenness during the growth process, such as uneven grain size distribution and increased defects. These defects will reduce the light absorption efficiency and photoelectric conversion efficiency of the perovskite layer, while increasing the leakage current and recombination loss of the device. These problems limit the performance improvement and application scope of inverse perovskite cells.

[0003] In order to solve the SAM layer agglomeration phenomenon in inverse perovskite cells, researchers have adopted strategies such as optimizing SAM molecular design, improving deposition process, introducing functional additives, and constructing composite hole transport layers to effectively address this challenge and improve device performance. Summary of the Invention

[0004] The purpose of the present invention is to solve the problem that clusters between self-assembled molecules will lead to uneven surface morphology of the SAM layer, which in turn affects the growth and coverage quality of the subsequent perovskite layer, resulting in a large number of holes at the bottom interface of the perovskite layer and poor film quality. A SAM layer with a surfactant and an inverse perovskite battery are provided.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A SAM layer with a surfactant comprises a self-assembling molecule and a surfactant, wherein the molecular formula of the surfactant comprises (CH3)2C(CH2) n XNH2 or (CH3)3C(CH2) n XNH2, where n≥1 and X is Cl - Br - or I - The surfactant is dispersed between the self-assembling molecules or the surfactant and the self-assembling molecules are layered and stacked, and the surfactant is used to inhibit the agglomeration of the self-assembling molecules and modify the perovskite layer.

[0007] The present invention adopts a SAM layer with a surfactant. The halogen groups in the surfactant have strong electronegativity and polarity and can form dipole-dipole interactions or hydrogen bonds with the polar groups on the self-assembled molecules, weakening the π-π interactions between the self-assembled molecules, thereby inhibiting the agglomeration of the self-assembled molecules, improving the uniformity of the distribution of the self-assembled molecules, forming a dense, defect-free single-molecule SAM layer, reducing the formation of pinholes and island aggregation, and thus improving the interface charge transfer efficiency; the halogen groups in the surfactant can also react with the uncoordinated Pb 2+ Coordination bonds are formed to simultaneously passivate the defects of the perovskite layer, while optimizing the orientation arrangement of the self-assembled molecules and reducing interface composite losses.

[0008] As a preferred embodiment of the present invention, n is an even number of 12-18.

[0009] As a preferred embodiment of the present invention, the surfactant comprises dodecyltrimethylammonium chloride, tetradecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, octadecyltrimethylammonium chloride, dodecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, octadecyltrimethylammonium bromide, dodecyltrimethylammonium iodide, tetradecyltrimethylammonium iodide, hexadecyltrimethylammonium iodide, octadecyltrimethylammonium iodide, dodecyldimethylbenzylammonium chloride, tetradecyldimethylbenzylammonium chloride, hexadecyldimethylbenzylammonium chloride, octadecyldimethylbenzylammonium chloride, dodecyldimethylbenzylammonium bromide, tetradecyldimethylbenzylammonium bromide, hexadecyldimethylbenzylammonium bromide, octadecyldimethylbenzylammonium bromide, dodecyldimethylbenzylammonium iodide, tetradecyldimethylbenzylammonium iodide, hexadecyldimethylbenzylammonium iodide or octadecyldimethylbenzylammonium iodide.

[0010] As a preferred embodiment of the present invention, the material of the surfactant is replaced by one of hexadecyldimethylbenzyl ammonium chloride, S-carboxyethylisothiourea betaine, S-carboxyethylisothiourea chloride, 3-sulfopropyltetradecyldimethyl betaine and 3-sulfopropylhexadecyldimethyl betaine.

[0011] As a preferred embodiment of the present invention, the self-assembling molecule comprises one of [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).

[0012] As a preferred embodiment of the present invention, the ratio of the added amount of the surfactant to the added amount of the self-assembling molecules is 1 to 3:1.

[0013] As a preferred embodiment of the present invention, the ratio of the added amount of the surfactant to the added amount of the self-assembling molecules is 0.2 to 0.9:1.

[0014] An inverse perovskite cell comprises a substrate, a hole transport layer, a SAM layer with a surfactant as described above, a perovskite layer, an electron transport layer and a metal electrode stacked in sequence.

[0015] The present invention adopts an inverse perovskite battery. The use of the surfactant can improve the uniformity and film-forming quality of the SAM layer, promote the directional transmission of holes / electrons, reduce carrier recombination, and improve the fill factor and open-circuit voltage of the inverse perovskite battery. The halogen group chemically bonds to the surface of the perovskite layer to fill lead vacancies and inhibit ion migration. At the same time, the regular arrangement of the self-assembled molecules reduces the interface state density and prolongs the carrier lifetime, thereby improving the photoelectric conversion efficiency of the inverse perovskite battery.

[0016] As a preferred embodiment of the present invention, it further comprises a hole blocking layer, which is arranged between the electron transport layer and the metal electrode. 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 5 to 10 nm.

[0017] As a preferred embodiment of the present invention, the hole transport layer comprises nickel oxide (NiO x ), one of 3-hexylthiophene (P3HT) and cuprous thiocyanate (CuSCN).

[0018] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0019] 1. A SAM layer having a surfactant, wherein the halogen groups in the surfactant have strong electronegativity and polarity and can form dipole-dipole interactions or hydrogen bonds with the polar groups on the self-assembled molecules, thereby weakening the π-π interactions between the self-assembled molecules, thereby inhibiting the agglomeration of the self-assembled molecules, improving the uniformity of the distribution of the self-assembled molecules, forming a dense, defect-free single-molecule SAM layer, reducing the formation of pinholes and island aggregation, and thus improving the interfacial charge transfer efficiency;

[0020] The halogen groups in the surfactant can also react with the uncoordinated Pb 2+ Form coordination bonds, synchronously passivate defects in the perovskite layer, optimize the orientation of self-assembled molecules, and reduce interface composite losses.

[0021] 2. An inverse perovskite cell uses a surfactant to improve the uniformity and film-forming quality of the SAM layer, promote the directional transport of holes / electrons, reduce carrier recombination, and enhance the fill factor and open-circuit voltage of the inverse perovskite cell. The chemical bonding of halogen groups to the surface of the perovskite layer fills lead vacancies and inhibits ion migration. At the same time, the regular arrangement of self-assembled molecules reduces the interface state density and prolongs the carrier lifetime, thereby improving the photoelectric conversion efficiency of the inverse perovskite cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 1 is a graph showing the photovoltaic performance test results of the Control cell in Example 3;

[0023] Figure 2 1 is a graph showing the photovoltaic performance test results of battery A in Example 3;

[0024] Figure 3 1 is a graph showing the photovoltaic performance test results of cell B in Example 3;

[0025] Figure 4 This is a graph showing the photovoltaic performance test results of battery C in Example 3. DETAILED DESCRIPTION

[0026] The present invention will be described in detail below with reference to the accompanying drawings.

[0027] 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.

[0028] Example 1

[0029] The SAM layer with surfactant used in the present invention comprises self-assembly molecules and surfactant, wherein the molecular formula of the surfactant comprises (CH3)2C(CH2) n XNH2 or (CH3)3C(CH2) n XNH2, where n≥1 and X is Cl - Br - or I - The surfactant is dispersed between the self-assembling molecules and is used to inhibit the agglomeration of the self-assembling molecules and modify the perovskite layer.

[0030] Furthermore, n is an even number ranging from 12 to 18.

[0031] Further, the surfactant comprises dodecyltrimethylammonium chloride, tetradecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, octadecyltrimethylammonium chloride, dodecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, octadecyltrimethylammonium bromide, dodecyltrimethylammonium iodide, tetradecyltrimethylammonium iodide, hexadecyltrimethylammonium iodide, octadecyltrimethylammonium iodide, dodecyldimethylbenzylammonium chloride, tetradecyldimethylbenzylammonium chloride, hexadecyldimethylbenzylammonium chloride, octadecyldimethylbenzylammonium chloride, dodecyldimethylbenzylammonium bromide, tetradecyldimethylbenzylammonium bromide, hexadecyldimethylbenzylammonium bromide, octadecyldimethylbenzylammonium bromide, dodecyldimethylbenzylammonium iodide, tetradecyldimethylbenzylammonium iodide, hexadecyldimethylbenzylammonium iodide or octadecyldimethylbenzylammonium iodide.

[0032] Furthermore, the material of the surfactant is replaced by one of hexadecyldimethylbenzyl ammonium chloride, S-carboxyethylisothiourea betaine, S-carboxyethylisothiourea chloride, 3-sulfopropyltetradecyldimethyl betaine and 3-sulfopropylhexadecyldimethyl betaine.

[0033] Furthermore, the self-assembling molecule comprises one of [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).

[0034] Furthermore, the ratio of the added amount of the surfactant to the added amount of the self-assembling molecules is 1 to 3:1.

[0035] Furthermore, the ratio of the added amount of the surfactant to the added amount of the self-assembling molecules is 0.2 to 0.9:1.

[0036] The halogen groups in the surfactant have strong electronegativity and polarity and can form dipole-dipole interactions or hydrogen bonds with the polar groups on the self-assembled molecules, weakening the π-π interactions between the self-assembled molecules, thereby inhibiting the agglomeration of the self-assembled molecules, improving the uniformity of the distribution of the self-assembled molecules, forming a dense, defect-free single-molecule SAM layer, reducing the formation of pinholes and island aggregation, and thus improving the interfacial charge transfer efficiency; the halogen groups in the surfactant can also react with the uncoordinated Pb 2+ Coordination bonds are formed to simultaneously passivate the defects of the perovskite layer, while optimizing the orientation arrangement of the self-assembled molecules and reducing interface composite losses.

[0037] In this embodiment, the preparation method of the self-assembled molecular layer is as follows:

[0038] Weigh 2 mg of hexadecyltrimethylammonium chloride and 2 mg of [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid (Me-4PACZ) and dissolve them in 1 ml of ethanol to obtain a surfactant solution and a self-assembling molecule solution. Mix 60 μl of each of the surfactant solution and the self-assembling molecule solution, apply the mixture to the top surface of the hole transport layer, and anneal at 100°C for 10 minutes to obtain the surfactant-containing SAM layer.

[0039] Example 2

[0040] The SAM layer with a surfactant used in the present invention is substantially the same as that in Example 1, except that the surfactant and the self-assembling molecules are stacked in layers.

[0041] In this embodiment, when the structure of the SAM layer having a surfactant is stacked in sequence as the self-assembly molecules and the surfactant, the preparation method is as follows:

[0042] Dissolve 1 mg of hexadecyltrimethylammonium chloride and 1 mg of [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid (Me-4PACZ) in 1 ml of ethanol to prepare a surfactant solution and a self-assembling molecule solution. Apply 50 μl of the self-assembling molecule solution to the top surface of the hole transport layer and anneal at 100°C for 10 minutes to form a self-assembled molecular layer. Apply another 50 μl of the surfactant solution to the top surface of the self-assembled molecular layer and anneal at 100°C for 10 minutes to form a surfactant-containing SAM layer.

[0043] In this embodiment, when the structure of the SAM layer having a surfactant is stacked in sequence with the surfactant and the self-assembling molecules, the preparation method is as follows:

[0044] Dissolve 1 mg of hexadecyltrimethylammonium chloride and 1 mg of [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid (Me-4PACZ) in 1 ml of ethanol to prepare a surfactant solution and a self-assembling molecule solution. Apply 50 μl of the surfactant solution to the top surface of the hole transport layer and anneal at 100°C for 10 minutes to form a surfactant layer. Apply another 50 μl of the self-assembling molecule solution to the top surface of the surfactant layer and anneal at 100°C for 10 minutes to form a surfactant-containing SAM layer.

[0045] Example 3

[0046] An inverted perovskite cell used in the present invention, based on any one of Examples 1 to 2, comprises a substrate, a hole transport layer, a SAM layer with a surfactant as described in Example 1, a perovskite layer, an electron transport layer and a metal electrode stacked in sequence.

[0047] Furthermore, it also includes a hole blocking layer, which is arranged between the electron transport layer and the metal electrode. 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 5 to 10 nm.

[0048] Furthermore, the hole transport layer material comprises nickel oxide (NiO x ), one of 3-hexylthiophene (P3HT) and cuprous thiocyanate (CuSCN).

[0049] The use of the surfactant can improve the uniformity and film-forming quality of the SAM layer, promote the directional transport of holes / electrons, reduce carrier recombination, and improve the fill factor and open-circuit voltage of the inverse perovskite battery; the chemical bonding of the halogen group to the surface of the perovskite layer fills lead vacancies and inhibits ion migration. At the same time, the regular arrangement of the self-assembled molecules reduces the interface state density and prolongs the carrier lifetime, thereby improving the photoelectric conversion efficiency of the inverse perovskite battery.

[0050] The preparation method of the inverse perovskite battery is as follows:

[0051] Preparation of the substrate: Indium tin oxide conductive glass (ITO) was used as the substrate in this embodiment. The substrate was ultrasonically cleaned with anhydrous ethanol, dried thoroughly, and then subjected to UV-ozone treatment for 20 minutes.

[0052] Preparation of the hole transport layer: In this embodiment, the hole transport layer is made of nickel oxide (NiO x ), and the hole transport layer with a thickness of 30 nm was prepared by magnetron sputtering.

[0053] Preparation of the SAM layer: The SAM layer is prepared in any of the methods described in Examples 1 to 2.

[0054] Preparation of the perovskite layer: Preparation of perovskite precursor solution. In this embodiment, a certain amount of FAI, PbI2, 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 0.05 FA 0.9 Pb(Br0.05 I 0.95 3. Perovskite precursor solution. The perovskite precursor solution was applied to the top surface of the SAM layer by spin coating. The perovskite layer was annealed at a temperature of 100° C. for 30 minutes. The resulting perovskite layer had a thickness of 400 nm.

[0055] The electron transport layer and the hole blocking layer are prepared. The material of the electron transport layer in this embodiment is [6,6]-phenyl-C71-butyric acid methyl ester, and the thickness of the electron transport layer is 30 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.

[0056] The metal electrode layer is prepared. In this embodiment, the material of the metal electrode is silver, and the thickness of the metal electrode is 200 nm.

[0057] In this example, inverse perovskite cells were prepared by stacking the surfactant and the self-assembling molecules in different orders and dispersing the surfactant in the self-assembling molecules, and their performances were compared.

[0058] The trans perovskite cell using only the self-assembled molecules as the SAM layer material is denoted as the Control cell; the trans perovskite cell in which the surfactant layer is first prepared and then the self-assembled molecule layer is denoted as the A cell; the trans perovskite cell in which the self-assembled molecule layer is first prepared and then the surfactant layer is denoted as the B cell; the trans perovskite cell made by mixing the surfactant and the self-assembled molecules is denoted as the C cell. The photovoltaic performance of the obtained perovskite solar cells: A1 cell, A2 cell, B1 cell, B2 cell, C1 cell and C2 cell was tested using a simulated light source system. The photovoltaic performance test results are shown in the figure. Figures 1 to 4 , as shown in Table 1.

[0059] Table 1

[0060] serial number <![CDATA[V oc ]]> <![CDATA[J sc ]]> FF(%) PCE (%) Control 11.14 2.00 69.55 15.55 A1 11.33 2.19 68.91 17.14 A2 11.25 2.17 69.83 17.05 B1 11.31 2.22 69.95 17.58 B2 11.37 2.21 70.89 17.84 C1 11.41 2.22 72.29 18.31 C2 11.46 2.20 72.15 18.19

[0061] from Figures 1 to 4 As can be seen from Table 1, the open circuit voltage (V oc ) and fill factor (FF) have been significantly improved, thereby greatly improving the photoelectric conversion efficiency of the perovskite cell. In particular, the trans perovskite cell made by mixing the surfactant and the self-assembled molecules is denoted as a C cell, which has a photoelectric conversion efficiency of about 60% higher than that of the Control cell using only self-assembled molecules as the SAM layer material. This is mainly the result of passivation modification of the SAM layer with a surfactant provided by the present invention.

[0062] 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 SAM layer having a surfactant, characterized in that: The invention comprises a self-assembling molecule and a surfactant, wherein the molecular formula of the surfactant comprises (CH3)2C(CH2) n XNH2 or (CH3)3C(CH2) n XNH2, where n≥1 and X is Cl - Br - or I - The surfactant is dispersed between the self-assembling molecules or the surfactant and the self-assembling molecules are layered and stacked, and the surfactant is used to inhibit the agglomeration of the self-assembling molecules and modify the perovskite layer.

2. The SAM layer having a surfactant according to claim 1, characterized in that: The value of n is an even number between 12 and 18.

3. The SAM layer having a surfactant according to claim 2, characterized in that: The surfactant comprises dodecyltrimethylammonium chloride, tetradecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, octadecyltrimethylammonium chloride, dodecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, octadecyltrimethylammonium bromide, dodecyltrimethylammonium iodide, tetradecyltrimethylammonium iodide, hexadecyltrimethylammonium iodide, octadecyltrimethylammonium iodide, dodecyldimethylbenzylammonium chloride, tetradecyldimethylbenzylammonium chloride, hexadecyldimethylbenzylammonium chloride, octadecyldimethylbenzylammonium chloride, dodecyldimethylbenzylammonium bromide, tetradecyldimethylbenzylammonium bromide, hexadecyldimethylbenzylammonium bromide, octadecyldimethylbenzylammonium bromide, dodecyldimethylbenzylammonium iodide, tetradecyldimethylbenzylammonium iodide, hexadecyldimethylbenzylammonium iodide or octadecyldimethylbenzylammonium iodide.

4. The SAM layer having a surfactant according to claim 2, characterized in that: The material of the surfactant is replaced by one of hexadecyldimethylbenzyl ammonium chloride, S-carboxyethylisothiourea betaine, S-carboxyethylisothiourea chloride, 3-sulfopropyltetradecyldimethyl betaine and 3-sulfopropylhexadecyldimethyl betaine.

5. A SAM layer having a surfactant according to any one of claims 1 to 4, characterized in that: The self-assembling molecules include one of [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).

6. The SAM layer having a surfactant according to claim 5, characterized in that: The ratio of the added amount of the surfactant to the added amount of the self-assembling molecules is 1 to 3:

1.

7. The SAM layer having a surfactant according to claim 6, characterized in that: The ratio of the added amount of the surfactant to the added amount of the self-assembling molecules is 0.2-0.9:

1.

8. An inverse perovskite battery, characterized in that: The method comprises a substrate, a hole transport layer, a SAM layer with a surfactant as claimed in any one of claims 1 to 7, a perovskite layer, an electron transport layer and a metal electrode stacked in sequence.

9. The inverse perovskite battery according to claim 8, characterized in that: The invention also comprises a hole blocking layer, which is arranged between the electron transport layer and the metal electrode. 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 5 to 10 nm.

10. The inverse perovskite battery according to claim 8, characterized in that: The hole transport layer comprises nickel oxide (NiO x ), 3-hexylthiophene (P3HT) or cuprous thiocyanate (CuSCN).

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