Method for preparing perovskite cell by modifying electron transport layer with natural organic molecules

Abstract

The invention discloses a method for preparing a perovskite cell by modifying an electron transport layer with natural organic molecules, and relates to the technical field of photovoltaic devices, and the method is characterized by comprising the following steps: mixing a tin dioxide solution with Ectoine, carrying out ultrasonic treatment, and filtering to obtain a tin dioxide and Ectoine mixed solution; performing ozone treatment on the cleaned and dried ITO transparent conductive glass substrate, and then depositing an Ec-SnO2 electron transport layer on the treated ITO substrate; preparing a perovskite precursor solution, preparing a perovskite thin film on an ITO substrate by using a spin-coating method, and then transferring the perovskite thin film to a heating table for annealing; spin-coating a hole transport layer on the perovskite thin film; and finally, depositing a silver electrode on the hole transport layer by adopting a thermal evaporation technology. According to the method, the photoelectric conversion efficiency and the stability of the perovskite solar cell are remarkably improved, the manufacturing process is simple and convenient, and the difficulty is relatively low.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic devices, and more specifically, to a method for preparing a perovskite cell by modifying an electron transport layer with natural organic molecules. Background Art

[0002] Perovskite solar cells have attracted extensive attention in recent years due to their high energy conversion efficiency, low manufacturing cost and solution processing characteristics. The photoelectric conversion efficiency has rapidly increased from the initial 3.8% to more than 26%, which is close to the level of silicon-based cells. However, the main obstacle to its practical application is the stability problem, especially the performance degradation caused by interface defects and residual stress. In a typical nip structure, the electron transport layer (ETL) plays a key role in charge extraction and transport; tin dioxide (SnO2) has a high electron mobility (240cm 2 / V·s), wide band gap (3.6eV), high light transmittance (>85%) and low photocatalytic activity, and are widely used as ETL materials.

[0003] However, SnO2 still has the following problems in practical applications:

[0004] Poor dispersibility: SnO2 nanoparticles tend to agglomerate in the dispersion, resulting in poor film coverage and high porosity, affecting the crystallization quality and interface contact of the perovskite layer;

[0005] Surface defects: oxygen vacancies and uncoordinated Sn 4+ Ions lead to intensified interface recombination, significantly reducing charge extraction efficiency and affecting photoelectric conversion performance;

[0006] Interface stress and poor contact: The difference in thermal expansion coefficients between SnO2 and perovskite causes residual stress, which further weakens the interface stability and device performance;

[0007] Unoptimized SnO2 films lead to non-radiative recombination rates as high as 10 4 s -1 , directly limits battery efficiency and stability;

[0008] Low adjustability of processed materials: The properties of industrial SnO2 materials are fixed, making it difficult to achieve personalized interface optimization, which restricts further performance improvement.

[0009] Therefore, the present invention aims to provide a method for preparing a perovskite battery by modifying an electron transport layer with natural organic molecules to solve the above problems. Summary of the invention

[0010] The purpose of the present invention is to provide a method for preparing a perovskite battery by modifying an electron transport layer with natural organic molecules. The present invention can effectively improve the performance of the SnO2 electron transport layer, passivate its surface defects through the interaction between edokine and SnO2, reduce electron-hole recombination, and improve the photoelectric conversion efficiency and stability of the perovskite solar cell. At the same time, the present invention does not need to change the existing battery preparation process, is simple and easy, and can significantly improve the stability of the device, especially the stability under long-term wet heat and ultraviolet light irradiation conditions.

[0011] The above technical objectives of the present invention are achieved through the following technical solutions: A method for preparing a perovskite battery by modifying an electron transport layer with natural organic molecules, comprising the following steps:

[0012] S1, prepare a SnO2 colloidal dispersion with a concentration of 10wt%, add a certain concentration of ectoine, perform ultrasonic treatment, and let it stand to ensure sufficient mixing to obtain a mixed solution of tin dioxide and ectoine;

[0013] S2, placing the cleaned ITO glass substrate in a spin coating device, dropping the mixed solution and spin coating at a certain speed, followed by annealing to form a SnO2 electron transport layer on the ITO glass substrate;

[0014] S3, mixing N,N-dimethylformamide and dimethyl sulfoxide as a mixed solvent to prepare a PbI2 solution with a concentration of 1.3M, and mixing 0.2M methylammonium chloride and formamidine iodide in a certain proportion to prepare a mixed organic halide solution;

[0015] S4, spin coating a PbI2 solution on the SnO2 electron transport layer, annealing to form a PbI2 film, and then spin coating a mixed organic halide solution on the PbI2 film, annealing to form a perovskite film;

[0016] S5, spin coating the hole transport layer material Spiro-OMeTAD on the perovskite film to form a hole transport layer;

[0017] S6. Depositing a silver electrode on the hole transport layer using thermal evaporation technology.

[0018] The present invention is further configured as follows: in the step S1, the added concentration of ectoine is 0.25 mg / mL, the ultrasonic treatment time is 30 minutes, and the standing time is 30 minutes.

[0019] The present invention is further configured as follows: the spin coating conditions in step S2 are 3000 rpm / 30 seconds, the annealing temperature is 150° C., and the time is 20 minutes.

[0020] The present invention is further configured as follows: in step S3, the volume ratio of N,N-dimethylformamide and dimethyl sulfoxide mixed is 4:1.

[0021] The present invention is further configured as follows: the condition for spin coating the PbI2 solution in step S4 is 1500rpm / 30 seconds, the heating condition for the PbI2 film is 70°C / 10 minutes, the condition for spin coating the mixed organic halide solution is 2000rpm / 30 seconds, and the annealing condition for the perovskite film is 100°C / 10 minutes.

[0022] The present invention is further configured as follows: the condition for spin coating the hole transport layer in step S5 is 3000 rpm / 30 seconds.

[0023] The present invention is further configured as follows: in step S6, the thickness of the silver electrode is 100 nm, and the evaporation rate is

[0024] In summary, the present invention has the following beneficial effects:

[0025] 1. The present invention effectively passivates the defects on the SnO2 surface through the interaction between edokine molecules and SnO2, reduces non-radiative recombination, and improves the electron extraction efficiency.

[0026] 2. The preparation method provided by the present invention is simple and easy, and can significantly improve the photoelectric conversion efficiency and stability of perovskite solar cells, especially the stability under conditions of humidity, heat and ultraviolet light irradiation.

[0027] 3. The preparation method of the present invention does not require changing the existing battery preparation process and is suitable for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagrams of top views of the tops on SnO2 and Ec-SnO2 in the embodiments of the present invention ((a) is a top view AFM image of the top on SnO2, (b) is a top view AFM image of the top on Ec-SnO2);

[0029] Figure 2 Schematic diagram of the effect of edokine on the crystallinity of PVK and the UV-visible spectrum in the embodiment of the present invention ((a) is a diagram of the effect of pre-embedded edokine on the crystallinity of PVK analyzed by X-ray diffraction, and (b) is a UV-visible spectrum diagram);

[0030] Figure 3 1 is a top view SEM image of PVK deposited in an embodiment of the present invention ((a) is a top view SEM image of the top of PVK deposited on SnO2, (b) is a top view SEM image of the top of PVK deposited on Ec-SnO2);

[0031] Figure 4 2 is a comparison diagram of voltage forward and reverse sweep efficiency between a control group and an experimental group in an embodiment of the present invention;

[0032] Figure 5 Schematic diagram of the long-term stability test results of perovskite solar cells in the embodiment of the present invention ((a) is the long-term stability result of unencapsulated PSCs stored in air with a relative humidity of 15-20%, (b) is the long-term stability result of unencapsulated PSCs stored in air with a relative humidity of 15-20%, and (c) is the long-term stability result of unencapsulated PSCs stored in air with a relative humidity of 15-20% under continuous ultraviolet irradiation (365nm, 50mW / cm 2 ) under long-term operation stability results. DETAILED DESCRIPTION

[0033] The following is combined with Figure 1-5 The present invention is described in further detail.

[0034] Embodiment: A method for preparing a perovskite cell by modifying an electron transport layer with natural organic molecules comprises the following steps:

[0035] S1: Take 10 mL of 10 wt% SnO2 colloidal dispersion.

[0036] S2: Add Ectoine molecules to the SnO2 dispersion at a ratio of 0.25 mg / mL and perform ultrasonic treatment at room temperature for 30 minutes to ensure that Ectoine and SnO2 are fully dispersed and combined.

[0037] S3: Let the mixed solution stand for 30 minutes to ensure the uniformity and stability of the solution.

[0038] S4: Place the cleaned ITO glass substrate in a spin coating device, drop 0.1 mL of SnO2 / edoquine mixed solution on the surface of the substrate, and spin coat at 3000 rpm for 30 seconds to ensure that the film is uniform and form a SnO2 electron transport layer.

[0039] S5: Place the deposited ITO glass slide on a hot plate at 150° C. and heat for 20 minutes to form a dense and crack-free SnO2 electron transport layer.

[0040] S6: The perovskite film was prepared by a two-step spin coating method; first, a 1.2 M PbI2 solution (the solvent is DMF and DMSO, with a volume ratio of 4:1) was prepared, and the solution was spin coated at a speed of 1500 rpm for 30 seconds, and heated at 70°C for 10 minutes to form a PbI2 film; then, a 0.2 M methylammonium iodide (MAI) and methylammonium bromide (MABr) solution (molar ratio of 4:1) was prepared and spin coated on the PbI2 film at a speed of 2000 rpm for 30 seconds, and then annealed at 100°C for 10 minutes to form a perovskite film.

[0041] S7: Spin-coat the hole transport layer material Spiro-OMeTAD on the perovskite film. The solution is 70 mg / mL of Spiro-OMeTAD dissolved in chlorobenzene. The amount added is 0.1 mL. The spin coating speed is 3000 rpm and the duration is 30 seconds.

[0042] S8: Using thermal evaporation technology, a silver (Ag) electrode is deposited on the top of the hole transport layer. The electrode thickness is 100nm and the evaporation rate is

[0043] This embodiment preferably also includes testing of the photoelectric performance of the perovskite solar cell, specifically including the photoelectric conversion efficiency (PCE), open circuit voltage (Voc), short circuit current density (Jsc) and fill factor (FF), such as Figure 4 As shown in the figure, it can be clearly found that the forward and reverse scanning efficiency of the experimental group is much higher than that of the control group, which shows that the passivation of the surface defects of SnO2 by edokine has a significant effect, and thus the efficiency is improved by more than 3%. In addition, a long-term stability test is also carried out in this embodiment, and the 365nm ultraviolet light (50mW / cm 2 ) for 90 hours and observe the efficiency decay ( Figure 5 a), the efficiency of the control group can retain nearly 67.79% of the original efficiency, while the experimental group can retain 85.19% of the initial efficiency; stored for 1700 hours under the condition of relative humidity of 15%-20% ( Figure 5 b), the control group retained 81.52% of the initial efficiency, while the efficiency of the experimental group remained almost unchanged, being able to maintain 93.21% of the initial efficiency.

[0044] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. A method for preparing a perovskite battery by modifying an electron transport layer with natural organic molecules, characterized in that: The following steps are involved: S1, prepare a SnO2 colloidal dispersion with a concentration of 10wt%, add a certain concentration of ectoine, perform ultrasonic treatment, and let it stand to ensure sufficient mixing to obtain a mixed solution of tin dioxide and ectoine; S2, placing the cleaned ITO glass substrate in a spin coating device, dropping the mixed solution and spin coating at a certain speed, followed by annealing to form a SnO2 electron transport layer on the ITO glass substrate; S3, mixing N,N-dimethylformamide and dimethyl sulfoxide as a mixed solvent to prepare a PbI2 solution with a concentration of 1.3M, and mixing 0.2M methylammonium chloride and formamidine iodide in a certain proportion to prepare a mixed organic halide solution; S4, spin coating a PbI2 solution on the SnO2 electron transport layer, annealing to form a PbI2 film, and continue to spin coating a mixed organic halide solution on the PbI2 film, annealing to form a perovskite film; S5, spin coating the hole transport layer material Spiro-OMeTAD on the perovskite film to form a hole transport layer; S6. Depositing a silver electrode on the hole transport layer using thermal evaporation technology.

2. The method for preparing a perovskite battery by modifying an electron transport layer with a natural organic molecule according to claim 1, characterized in that: In the step S1, the concentration of ectoine added is 0.25 mg / mL, the ultrasonic treatment time is 30 minutes, and the standing time is 30 minutes.

3. The method for preparing a perovskite battery by modifying an electron transport layer with a natural organic molecule according to claim 1, characterized in that: The spin coating conditions in step S2 are 3000 rpm / 30 seconds, the annealing temperature is 150° C., and the time is 20 minutes.

4. The method for preparing a perovskite battery by modifying an electron transport layer with a natural organic molecule according to claim 1, characterized in that: In step S3, the volume ratio of N,N-dimethylformamide and dimethyl sulfoxide is 4:

1.

5. The method for preparing a perovskite battery by modifying an electron transport layer with a natural organic molecule according to claim 1, characterized in that: In step S4, the conditions for spin coating the PbI2 solution are 1500 rpm / 30 seconds, the heating conditions for the PbI2 film are 70°C / 10 minutes, the conditions for spin coating the mixed organic halide solution are 2000 rpm / 30 seconds, and the annealing conditions for the perovskite film are 100°C / 10 minutes.

6. The method for preparing a perovskite battery by modifying an electron transport layer with a natural organic molecule according to claim 1, characterized in that: The condition for spin coating the hole transport layer in step S5 is 3000 rpm / 30 seconds.

7. The method for preparing a perovskite battery by modifying an electron transport layer with a natural organic molecule according to claim 1, characterized in that: The thickness of the silver electrode in step S6 is 100 nm, and the evaporation rate is

Images