Perovskite solar cell based on benzamide bromide modification and preparation method thereof

Abstract

The application provides a benzamide bromide-modified perovskite solar cell and a preparation method thereof, and belongs to the technical field of perovskite solar cells; the application solves the problem of low photoelectric conversion rate and poor stability of existing perovskite solar cells caused by uncoordinated lead ions; the application comprises the following steps: S1, placing a substrate covered with a transparent metal electrode into deionized water, acetone and ethanol for ultrasonic cleaning in sequence, and then drying and treating by ultraviolet ozone to form a conductive substrate; S2, spin coating an electron transport layer on the conductive substrate; S3, spin coating and depositing a perovskite active layer on the surface of the electron transport layer, wherein the perovskite active layer uses benzamide bromide as a passivation agent; S4, spin coating a hole transport material on the surface of the perovskite active layer to obtain a hole transport layer; and S5, evaporating a metal electrode on the hole transport layer; the application is applied to perovskite solar cells.

Description

Technical Field

[0001] This invention provides a perovskite solar cell based on benzamide bromide modification and its preparation method, belonging to the field of perovskite solar cell technology. Background Technology

[0002] In recent years, perovskite materials have attracted widespread attention in the field of solar cells due to their advantages such as high carrier mobility, large light absorption coefficient, long carrier lifetime, long carrier diffusion length, and low cost. Although perovskite solar cells have made rapid progress, many problems still need further in-depth research in advancing their industrialization. Among these, the quality of the perovskite thin film is a decisive factor affecting the photoelectric conversion efficiency and environmental stability of perovskite solar cells. Therefore, preparing high-quality perovskite thin films with controllable morphology and uniform coverage is particularly important for improving the efficiency and stability of perovskite solar cells.

[0003] 1. Patent application CN202011446848.9 discloses a highly stable perovskite solar cell based on maleimide undecanoic acid modification and its preparation method. By adding maleimide undecanoic acid to the perovskite precursor, a -COOH functional group containing a long alkyl chain is introduced as a passivating agent. During thermal annealing, the long alkyl chain is expelled onto the perovskite surface to form a hydrophobic passivation layer, which suppresses nonradiative recombination of charge carriers and significantly improves the device's resistance to humidity.

[0004] 2. Chen et al. reported that polyacrylonitrile (PAN) was used to passivate uncoordinated lead cations in perovskite films. The cyano group had a stronger coordination ability than the carbon group used normally, and the strong coordination could reduce the I / Pb ratio on the film surface. (Angew. Chem. Int. Ed. 2022, 61, e202113932).

[0005] 3. Wang et al. reported that by using two organic hydroiodates, namely phenylethyl iodide and o-fluorophenylethyl iodide, a passivation layer was formed on the surface of perovskite polycrystalline thin films, which effectively suppressed the defect recombination behavior on the surface and at the grain boundaries of the polycrystalline thin films. (Wang Song, Hou Youzheng, Zhang Fan, et al. Influence of passivation layer on defect recombination behavior in perovskite solar cells [J]. Journal of Luminescence, 2021, 42(7):1029-1039. DOI:10.37188 / CJL.20210103.)

[0006] In the existing technology, perovskite thin films still have a large number of defects. Uncoordinated lead ions, due to their low formation energy, are one of the main reasons for the formation of defects. Uncoordinated lead ions can induce recombination of photogenerated carriers on the one hand, and provide a pathway for ion migration on the other hand, which further leads to the degradation of the photoelectric conversion efficiency of perovskite solar cells and poor device stability. Summary of the Invention

[0007] To address the problems of low photoelectric conversion efficiency and poor stability in existing perovskite solar cells due to the presence of uncoordinated lead ions, this invention proposes a perovskite solar cell based on benzamide bromide modification and its preparation method.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for preparing perovskite solar cells based on benzamide bromide modification, comprising the following steps:

[0009] S1: The substrate covered with transparent metal electrodes is sequentially immersed in deionized water, acetone, and ethanol for ultrasonic cleaning, dried, and then treated with ultraviolet ozone to form a conductive substrate.

[0010] S2: Spin-coating an electron transport layer onto a conductive substrate;

[0011] S3: A perovskite active layer is spin-coated onto the surface of the electron transport layer, wherein the perovskite active layer uses benzamide bromide as a passivating agent;

[0012] S4: A hole transport layer is obtained by spin-coating a hole transport material onto the surface of the perovskite active layer.

[0013] S5: Deposit a metal electrode on the hole transport layer.

[0014] In step S3, the perovskite active layer is spin-coated onto the surface of the electron transport layer using a two-step spin-coating method.

[0015] The specific steps of the two-step spin coating method are as follows:

[0016] S3.1: Lead iodide and benzamide bromide are dissolved in a mixed solvent of N,N-dimethylformamide DMF and dimethyl sulfoxide DMSO to prepare a precursor solution. The precursor solution is then spin-coated onto the surface of the electron transport layer to obtain a PbI2 film doped with benzamide bromide.

[0017] S3.2: Mix formamidinium iodide (FAI), methylaminomethane (MAI), and methylammonium chloride (MACl), then dissolve them in isopropanol solution. Spin-coat the dissolved solution onto the obtained benzamide bromide-doped PbI2 film and perform heat treatment to obtain a perovskite film.

[0018] Lead iodide and benzamide bromide were dissolved in 1 mL of a mixed solvent of N,N-dimethylformamide DMF and dimethyl sulfoxide DMS at a volume ratio of (50-150):(1-10).

[0019] The volume ratio of DMF to DMSO in the mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) is 9:1.

[0020] The heat treatment conditions in step 3.2 are 80–120°C for 10–60 min.

[0021] The formamidinium iodide (FAI), methylaminomethane (MAI), and methylammonium chloride (MACl) are mixed in a mass ratio of 10:1:1.

[0022] Lead iodide and benzamide bromide were dissolved in 1 mL of a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) at a volume ratio of 1:0.03.

[0023] The perovskite solar cell based on benzamide bromide modification includes, from bottom to top, an ITO conductive glass substrate, an electron transport layer, a perovskite layer, a hole transport layer and a silver electrode. The upper surface of the electron transport layer is spin-coated with a perovskite active layer, which uses benzamide bromide as a passivating agent.

[0024] The perovskite in the perovskite active layer is made of MA. x FA 1-x PbI y Cl 3-y The mixed perovskite, wherein the perovskite active layer of the electron transport layer is spin-coated using a two-step method, the specific steps of which are as follows:

[0025] Lead iodide and benzamide bromide were dissolved in a mixed solvent of N,N-dimethylformamide DMF and dimethyl sulfoxide DMSO to prepare a precursor solution. The precursor solution was then spin-coated onto the surface of the electron transport layer to obtain a PbI2 film doped with benzamide bromide.

[0026] A mixture of formammonium iodide (FAI), methylaminomethane (MAI), and methylammonium chloride (MACl) was dissolved in isopropanol solution. The dissolved solution was then spin-coated onto the resulting PbI2 film doped with benzamide bromide and subjected to heat treatment to obtain a perovskite film.

[0027] The advantages of this invention over the prior art are as follows:

[0028] 1. Benzamide bromide can passivate surface defects in perovskite layers, utilizing the carbonyl group (–NH3). +The coordination between the group and lead ions effectively controls the nucleation and crystal growth of the light-absorbing layer of organohalide lead perovskite;

[0029] 2. It helps to suppress charge recombination and promote charge transport;

[0030] 3. The perovskite light-absorbing layer and the electron transport layer form a good ohmic contact;

[0031] 4. The perovskite grains are more compact and significantly larger, resulting in higher film quality;

[0032] 5. The ion activation energy is significantly enhanced, effectively inhibiting ion migration;

[0033] 6. The photoelectric conversion efficiency is significantly improved, the cost is reduced, the repeatability is good, the mechanical stability is good, and it has good application prospects. Attached Figure Description

[0034] The present invention will be further described below with reference to the accompanying drawings:

[0035] Figure 1 This is a schematic diagram of the perovskite solar cell structure of the present invention;

[0036] Figure 2 Comparison of X-ray diffraction patterns of perovskite without benzamide bromide based on existing technology and perovskite based on benzamide bromide using the invention;

[0037] Figure 3 Scanning electron microscope (SEM) images of perovskites without benzamide bromide doping, based on existing technologies.

[0038] Figure 4 The image shows the scanning electron microscope morphology of the perovskite based on doped benzamide bromide according to the present invention.

[0039] Figure 5 A comparison chart of the short-circuit current and open-circuit voltage curves of the existing undoped benzamide bromide perovskite solar cell and the present invention based on benzamide bromide perovskite solar cell under AM1.5G sunlight.

[0040] Figure 6 This is a comparison of the temperature and corresponding conductivity curves of the perovskite solar cells based on the prior art (undoped benzamide bromide) and the present invention (doped benzamide bromide).

[0041] Figure 7 The image shows a comparison of the Pb4f XPS spectra of perovskite without benzamide bromide based on existing technology and perovskite based on benzamide bromide based on the present invention. Detailed Implementation

[0042] like Figures 1 to 7As shown, this invention proposes a perovskite solar cell based on benzamide bromide modification. Benzamide bromide is used as a passivating agent in the passivation of defects in the perovskite thin film, and its carbonyl groups and (–NH3) groups... + The group can interact with lead ions, thereby passivating unbonded lead ions in the lattice, reducing their recombination with photogenerated charge carriers, promoting charge transport, significantly enhancing ion activation energy, and effectively suppressing ion migration, thus achieving the goal of effectively improving the photoelectric performance and stability of upright planar perovskite solar cells. Figure 1 This is a device structure diagram of a perovskite solar cell prepared by the method of the present invention. From bottom to top, it consists of an ITO conductive glass substrate, an electron transport layer, a perovskite layer, a hole transport layer, and a silver electrode.

[0043] The specific fabrication process of the perovskite solar cell based on benzamide bromide modification of the present invention is as follows:

[0044] 1. The substrate covered with transparent metal electrodes was sequentially immersed in deionized water, acetone, and ethanol for ultrasonic cleaning, dried, and then treated with ultraviolet ozone for 15 minutes.

[0045] 2. Spin-coat an electron transport layer onto a conductive substrate;

[0046] 3. A perovskite active layer is spin-coated and deposited on the surface of the electron transport layer;

[0047] 4. A hole transport layer is obtained by spin-coating a hole transport material onto the surface of the perovskite active layer.

[0048] 5. Deposit a metal electrode onto the hole transport layer.

[0049] A two-step spin-coating method is used to spin-coat the perovskite active layer on the electron transport layer surface. The specific steps are as follows:

[0050] 1. Lead iodide and benzamide bromide were dissolved in 1 mL of a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) at a volume ratio of (50-150):(1-10) to prepare a precursor solution. The volume ratio of DMF to DMSO in the mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) was 9:1. The precursor solution was spin-coated onto the surface of the electron transport layer at a spin-coating rate of 1500 r / min for 30 s. The coating was then heat-treated at 70 °C for 1 min to obtain a PbI2 thin film.

[0051] 2. Mix formamidinium iodide (FAI), methylaminomethane (MAI), and methylammonium chloride (MACl) in a mass ratio of 10:1:1, then dissolve them in 2 mL of isopropanol solution. Spin-coat the solution onto the obtained PbI2-doped benzamide bromide film and heat-treat it at 80–120 °C for 10–60 min to obtain a perovskite film.

[0052] Example 1

[0053] The specific fabrication process of perovskite solar cells is as follows:

[0054] 1. The substrate covered with transparent metal electrodes was sequentially immersed in deionized water, acetone, and ethanol for ultrasonic cleaning, dried, and then treated with ultraviolet ozone for 15 minutes.

[0055] 2. Spin-coat an electron transport layer onto a conductive substrate;

[0056] 3. A perovskite active layer is spin-coated and deposited on the surface of the electron transport layer;

[0057] 4. A hole transport layer is obtained by spin-coating a hole transport material onto the surface of the perovskite active layer.

[0058] 5. Deposit a metal electrode onto the hole transport layer.

[0059] A two-step spin-coating method is used to spin-coat the perovskite active layer on the electron transport layer surface. The specific steps are as follows:

[0060] 1. Lead iodide and benzamide bromide were dissolved in 1 mL of a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) at a volume ratio of 1:0.03 to obtain a precursor solution. The volume ratio of DMF to DMSO in the mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) was 9:1. The precursor solution was spin-coated onto the surface of the electron transport layer at a spin-coating rate of 1500 r / min for 30 s. The coating was then heat-treated at 70 °C for 1 min to obtain a PbI2 thin film.

[0061] 2. Mix formamidinium iodide (FAI), methylaminomethane (MAI), and methylammonium chloride (MACl) in a mass ratio of 10:1:1, then dissolve them in 2 mL of isopropanol solution. Spin-coat the solution onto the obtained PbI2-doped benzamide bromide film and heat-treat it at 80–120 °C for 10–60 min to obtain a perovskite film.

[0062] Figure 2 a is the X-ray diffraction pattern of undoped perovskite based on existing technology. Figure 2b is the X-ray diffraction pattern of perovskite based on doped benzamide bromide. Compared with the existing technology, the peak intensity of PbI2 is significantly reduced, indicating that the device stability is improved. The main peak intensity of perovskite (100) is significantly increased, indicating that the crystal orientation of perovskite is enhanced, which is beneficial to the charge transport inside perovskite.

[0063] Figure 3 This is a scanning electron microscope image of undoped perovskite based on existing technology.

[0064] Figure 4 The image shows the scanning electron microscope morphology of perovskite based on benzamide bromide doping. Compared with the prior art, the perovskite grains prepared by the method of this invention are more compact and significantly larger, resulting in higher film quality. Excess PbI2 disappears, which is beneficial to improving the photoelectric performance and stability of the device.

[0065] Figure 5 a represents the short-circuit current and open-circuit voltage curves of a conventional undoped perovskite solar cell measured under AM1.5G sunlight. Figure 5 b shows the short-circuit current and open-circuit voltage curves of a perovskite solar cell based on doped benzamide bromide under AM1.5G sunlight. Compared with the prior art, the short-circuit current and open-circuit voltage of the perovskite solar cell are significantly improved, and the photovoltaic performance of the device is significantly improved.

[0066] Figure 6 a represents the temperature versus corresponding conductivity curve of a device based on existing technology without benzamide bromide doping. Figure 6 b shows the device temperature and corresponding conductivity curves based on doped benzamide bromide. Compared with the prior art, the ion activation energy is significantly increased from 0.057 eV to 0.130 eV, indicating that ion migration is effectively suppressed.

[0067] Figure 7 a represents the Pb4f XPS spectrum of perovskite without benzamide bromide doping based on existing technology. Figure 7 b shows the Pb4f XPS spectrum of perovskite based on doped benzamide bromide. Compared with existing techniques, the Pb4f energy level shifts to higher energy levels, indicating that the benzamide bromide molecule interacts with uncoordinated Pb. 2+ There is a strong interaction between them, metal Pb 0 The complete disappearance of the peak indicates that the modification with benzamide bromide can effectively passivate defects in the perovskite film.

[0068] The high-efficiency perovskite solar cell based on benzamide bromide modification provided by this invention utilizes the carbonyl group and (–NH3) in benzamide bromide. + The interaction between the group and lead ions passivates lead defects, significantly reduces the defect state density, effectively suppresses nonradiative recombination, and promotes good carrier transport from perovskite to the hole transport layer.

[0069] Regarding the specific structure of this invention, it should be noted that the connection relationships between the various component modules used in this invention are definite and achievable. Except as specifically described in the embodiments, their specific connection relationships can bring about corresponding technical effects and solve the technical problems proposed by this invention without relying on the execution of corresponding software programs. The models of the components, modules, and specific components appearing in this invention, the connection methods between them, and the conventional usage methods and expected technical effects brought about by the above technical features, unless specifically described, are all publicly disclosed content in patents, journal articles, technical manuals, technical dictionaries, and textbooks that can be obtained by those skilled in the art before the application date, or belong to conventional technology, common knowledge, and other existing technologies in this field. There is no need to elaborate, which makes the technical solution provided in this case clear, complete, and achievable, and can reproduce or obtain corresponding physical products based on this technical means.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a perovskite solar cell based on benzamide bromide modification, characterized in that: Includes the following steps: S1: The substrate covered with transparent metal electrodes is sequentially immersed in deionized water, acetone, and ethanol for ultrasonic cleaning, dried, and then treated with ultraviolet ozone to form a conductive substrate. S2: Spin-coating an electron transport layer onto a conductive substrate; S3: A perovskite active layer is spin-coated onto the surface of the electron transport layer, wherein the perovskite active layer uses benzamide bromide as a passivating agent; In step S3, the perovskite active layer is spin-coated onto the surface of the electron transport layer using a two-step spin-coating method. The specific steps of the two-step spin coating method are as follows: S3.1: Lead iodide and benzamide bromide are dissolved in a mixed solvent of N,N-dimethylformamide DMF and dimethyl sulfoxide DMSO to prepare a precursor solution. The precursor solution is then spin-coated onto the surface of the electron transport layer to obtain a PbI2 film doped with benzamide bromide. S3.2: Mix formammonium iodide (FAI), methylaminomethane (MAI), and methylammonium chloride (MACl), then dissolve them in isopropanol solution. Spin-coat the dissolved solution onto the obtained PbI2 film doped with benzamide bromide and heat-treat it to obtain a perovskite film. S4: A hole transport layer is obtained by spin-coating a hole transport material onto the surface of the perovskite active layer. S5: Deposit a metal electrode on the hole transport layer.

2. The method for preparing a perovskite solar cell based on benzamide bromide modification according to claim 1, characterized in that: Lead iodide and benzamide bromide were dissolved in 1 mL of a mixed solvent of N,N-dimethylformamide DMF and dimethyl sulfoxide DMS at a volume ratio of (50-150):(1-10).

3. The method for preparing a perovskite solar cell based on benzamide bromide modification according to claim 2, characterized in that: The volume ratio of DMF to DMSO in the mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) is 9:

1.

4. The method for preparing a perovskite solar cell based on benzamide bromide modification according to claim 1, characterized in that: The heat treatment conditions in step 3.2 are 80–120°C for 10–60 min.

5. The method for preparing a perovskite solar cell based on benzamide bromide modification according to claim 1, characterized in that: The formamidinium iodide (FAI), methylaminomethane (MAI), and methylammonium chloride (MACl) are mixed in a mass ratio of 10:1:

1.

6. The method for preparing a perovskite solar cell based on benzamide bromide modification according to claim 2, characterized in that: Lead iodide and benzamide bromide were dissolved in 1 mL of a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) at a volume ratio of 1:0.

03.

7. A perovskite solar cell based on benzamide bromide modification, characterized in that: The device comprises, from bottom to top, an ITO conductive glass substrate, an electron transport layer, a perovskite layer, a hole transport layer, and a silver electrode. The upper surface of the electron transport layer is spin-coated with a perovskite active layer, which uses benzamide bromide as a passivating agent. The perovskite in the perovskite active layer is made of MA. x FA 1-x PbI y Cl 3-y The upper surface of the electron transport layer is spin-coated with a perovskite active layer using a two-step spin-coating method. The specific steps of the two-step spin-coating method are as follows: Lead iodide and benzamide bromide were dissolved in a mixed solvent of N,N-dimethylformamide DMF and dimethyl sulfoxide DMSO to prepare a precursor solution. The precursor solution was then spin-coated onto the surface of the electron transport layer to obtain a PbI2 film doped with benzamide bromide. A mixture of formammonium iodide (FAI), methylaminomethane (MAI), and methylammonium chloride (MACl) was dissolved in isopropanol solution. The dissolved solution was then spin-coated onto the resulting PbI2 film doped with benzamide bromide and subjected to heat treatment to obtain a perovskite film.

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