The invention relates to a method for preparing 2, 2apos; perovskite solar cell modified by-azobis (isobutylamidine) dihydrochloride

Abstract

The invention provides a perovskite solar cell modified by 2, 2 '-azobis (isobutylamidine) dihydrochloride and a preparation method of the perovskite solar cell. 2, 2 '-azobis (isobutylamidine) dihydrochloride is used as an interface modification material, a spin-coating method is adopted to spin-coat a 2, 2'-azobis (isobutylamidine) dihydrochloride aqueous solution on the interface of the electron transport layer and the perovskite layer, and a two-step spin-coating method is adopted to prepare the perovskite solar cell. According to the invention, amidino cations in 2, 2 '-azobis (isobutylamidine) dihydrochloride interact with perovskite, so that carrier recombination at the interface of an electron transport layer and a perovskite layer is reduced, the short-circuit current density is increased by about 2mA. Cm <-2 >, and PCE is increased by 2%. The invention also provides a preparation method of the interface modified perovskite solar cell, and important reference is provided for realizing industrialization of the solar cell.

Description

Technical Field

[0001] The invention relates to a perovskite solar cell modified with 2,2'-azobisisobutylamidine dihydrochloride, and belongs to the field of energy technology. Background Art

[0002] After years of development, solar cells have evolved into numerous types, including silicon solar cells, multi-element thin-film solar cells, dye-sensitized solar cells, and perovskite solar cells. Perovskite solar cells (PSCs), a new generation of solar cells, have achieved certified efficiencies of 26.1% in just a decade of development, exceeding the efficiency limit of silicon solar cells. These cells also offer advantages such as low manufacturing cost, simple processing, and high efficiency, making them a hot topic in solar cell research.

[0003] Perovskite solar cells (PSCs) primarily consist of five components: a transparent conductive substrate, an electron transport layer (ETL), a perovskite layer, a hole transport layer (HTL), and electrodes. The perovskite layer, serving as the light-absorbing layer, has a significant impact on the conversion efficiency of the PSC. Energy level matching and defects at the film interfaces (between the ETL and perovskite layer, and between the perovskite layer and the HTL) are also crucial factors influencing PSC conversion efficiency. Due to inherent material properties, perovskites are prone to developing different phase structures and numerous vacancy defects. They are susceptible to decomposition by external elements such as water, oxygen, and high temperatures, impacting the efficiency and stability of PSCs. Nitrogen, with its lone pair of electrons, has been shown to effectively passivate vacancies and crystal defects in perovskites and is therefore often used as a dopant or interface modification material to enhance PSC performance. Amidino groups, as ligands containing nitrogen, can interact with perovskites, passivating defects and filling organic cation vacancies, thereby increasing carrier mobility, boosting short-circuit current, and improving photoelectric conversion efficiency.

[0004] Spin-coating 2,2'-azobisisobutylamidine dihydrochloride as an interface modification material between the SnO2 electron transport layer and the perovskite layer can reduce the interface mismatch between the SnO2 electron transport layer and the perovskite layer, while passivating SnO2 surface defects, reducing the interlayer carrier recombination rate, and improving device efficiency. This has certain reference significance in the field of solar cells, which focuses on photoelectric conversion efficiency. Summary of the Invention

[0005] The present invention aims to prepare a perovskite solar cell with high conversion efficiency by introducing a 2,2'-azobisisobutylamidine dihydrochloride modified layer. 2,2'-azobisisobutylamidine dihydrochloride can optimize perovskite crystallization, thereby enhancing cell stability, accelerating carrier transport, and improving the cell's photoelectric conversion efficiency.

[0006] Another object of the present invention is to provide a method for preparing perovskite solar cells using a two-step spin coating method. This method has low production cost, high production efficiency, is green and environmentally friendly, and has simple equipment, which is more conducive to actual production and provides an important reference for the preparation of perovskite solar cells.

[0007] In order to achieve the above objectives, the present invention provides the following technical solutions:

[0008] A method for preparing a perovskite solar cell modified with 2,2'-azobisisobutylamidine dihydrochloride comprises the following steps:

[0009] Step 1: Clean the FTO conductive glass;

[0010] Step 2: Preparation of 2,2'-azobisisobutylamidine dihydrochloride interface-modified perovskite solar cells;

[0011] Step 3: Weigh 9.9-10.1 mg of 2,2'-azobisisobutylamidine dihydrochloride powder and 1 mL of H2O to prepare a 2,2'-azobisisobutylamidine dihydrochloride solution, stir and mix thoroughly, and store at low temperature;

[0012] Step 4: Spin-coating the 2,2'-azobisisobutylamidine dihydrochloride solution on the FTO conductive glass and then annealing the glass;

[0013] Preferably, the spin coating speed of the 2,2'-azobisisobutylamidine dihydrochloride solution is 2000-4000 rpm, the spin coating time is 20-40 s, and the acceleration is 2000-3000.

[0014] Preferably, the annealing temperature of the 2,2'-azobisisobutylamidine dihydrochloride modified layer is 120-150° C., and the annealing time is 5-15 min.

[0015] Step 4: preparing a perovskite light-absorbing layer on the step 3;

[0016] Step 5: Prepare a hole transport layer on the perovskite light-absorbing layer, and prepare Ag and Au electrodes by physical vapor deposition to prepare a perovskite solar cell modified with 2,2'-azobisisobutylamidine dihydrochloride.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention provides a method for preparing a perovskite solar cell modified with 2,2'-azobisisobutylamidine dihydrochloride, wherein the amidine ligand in 2,2'-azobisisobutylamidine dihydrochloride reacts with [PbI6] 4+ Octahedral bonding passivates crystal defects, which is beneficial to improving the photoelectric conversion efficiency of the battery.

[0019] This method, for the first time, spin-coats an organic salt solution of 2,2'-azobisisobutylamidine dihydrochloride onto SnO2 (the electron transport layer), resulting in a higher-quality perovskite film. This method also offers low production cost and simple operation, providing an important reference for the research of perovskite solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Attachment Figure 1 :JV curves of perovskite solar cells with control group and SnO2 electron transport layer modified with different concentrations of 2,2'-azobisisobutylamidine dihydrochloride

[0021] Attachment Figure 2 :Current stability of perovskite films with SnO2 electron transport layer modified by control group and 3mg / mL 2,2'-azobisisobutylamidine dihydrochloride

[0022] Attachment Figure 3 :XRD patterns of perovskite films of (a) control group and (b) 3mg / mL 2,2'-azobisisobutylamidine dihydrochloride modified SnO2 electron transport layer DETAILED DESCRIPTION

[0023] The present invention will be further described below with reference to the accompanying drawings and examples.

[0024] 1. Preparation of perovskite solar cells

[0025] 1: Cleaning of FTO conductive glass

[0026] Wipe the surface of the FTO conductive glass with detergent, and ultrasonically clean it with anhydrous ethanol, isopropyl alcohol, UP water, and anhydrous ethanol for 15 minutes in sequence. Put the cleaned FTO conductive glass into an oven for drying.

[0027] 2: Preparation of precursor solution

[0028] 1 mL of SnO2 aqueous solution and 5 mL of UP water were measured in a volume ratio of 1:5, and stirred at room temperature to mix evenly; an aqueous solution of 2,2'-azobisisobutylamidine dihydrochloride was prepared at a concentration of 10 mg / mL; 600 mg of PbI2 powder, 9 mg of PbCl2 powder, 16.9 mg of CsI powder, 0.9 mL of DMF, and 0.1 mL of DMSO were weighed according to a perovskite molar concentration of 1.3 M, and the mixture was heated and stirred in a glove box for 6 to 8 hours, hereinafter referred to as precursor solution 1; 60 mg of FAI powder, 6 mg of MACl powder, 6 mg of MABr powder, and 1 mL of IPA were weighed, and the mixture was stirred in a glove box for 6 to 8 hours, hereinafter referred to as precursor solution 2; 72.3 mg of Spiro-OMeTAD powder, 1 mL of chlorobenzene, 29 μL of TBP, and 17.5 μL of The acetonitrile solution of Li-TFSI was mixed and stirred in a glove box for 2 to 4 hours, hereinafter referred to as the Spiro solution. The acetonitrile solution of Li-TFSI was weighed at a ratio of 520 mg:1 mL, and the Li-TFSI powder and acetonitrile solution were mixed evenly in the glove box.

[0029] 3: Preparation of perovskite thin films

[0030] Preheat the hot plate to 150°C. Clean the dried FTO conductive glass with UV-ozone for 15 minutes. Use a syringe to draw an appropriate amount of SnO2 aqueous solution and filter it through an inorganic filter to obtain a SnO2 aqueous solution free of particulate impurities. Use a pipette to dilute the 2,2'-azobisisobutylamidine dihydrochloride aqueous solution to 0 mg / mL, 1 mg / mL, 3 mg / mL, and 5 mg / mL. Ultrasonicate the diluted 2,2'-azobisisobutylamidine dihydrochloride aqueous solution for 2 minutes. Turn on the spin coater and set the spin coating parameters: speed 3000 rpm, acceleration 2000, and spin coating time 30 seconds. After the temperature of the hot plate is raised to 150°C and the FTO conductive glass is cleaned, use tweezers to move the FTO conductive glass to the turntable of the spin coater, turn on the vacuum pump to adsorb the FTO conductive glass, use a pipette to transfer 50 μL of SnO2 aqueous solution and spread it evenly on the FTO conductive glass, turn on the spin coater to spin coat the SnO2 aqueous solution, and after spin coating, move the FTO conductive glass to the hot plate for annealing for 30 minutes to form a SnO2 film on the FTO conductive glass.

[0031] After annealing is completed, the annealed FTO conductive glass is moved to the turntable of the coating machine, the vacuum adsorption is turned on, and 50 μL of 2,2'-azobisisobutylamidine dihydrochloride aqueous solution is transferred with a pipette and spread evenly on the FTO conductive glass. The solution is spin-coated for 30 seconds according to the same spin-coating parameters. After spin coating, the FTO conductive glass is moved to a hot plate and annealed for 15 minutes. This step is repeated to form a control group without 2,2'-azobisisobutylamidine dihydrochloride and a control group containing 1 mg / mL, 3 mg / mL, and 5 mg / mL of 2,2'-azobisisobutylamidine dihydrochloride, respectively.

[0032] After all FTO conductive glass is annealed, store it at room temperature. Before spin-coating precursor solution 1, clean the FTO conductive glass coated with SnO2 and 2,2'-azobisisobutylamidine dihydrochloride with UV-ozone for 15 minutes. During this time, preheat the hotplates to 70°C and 150°C, respectively. Set the spin-coating parameters as follows: speed 1500 rpm, acceleration 750, and spin-coating time 30 seconds. After cleaning the FTO conductive glass, transfer it to a glove box. Use tweezers to transfer the FTO conductive glass to the spin coater turntable. Turn on the vacuum suction. Use a pipette to slightly spread 80 μL of precursor solution 1 on the FTO conductive glass and spin coat for 30 seconds. After spin coating, transfer the glass to a 70°C hot plate for annealing for 10-15 seconds. After cooling, transfer the glass to the spin coater turntable. Turn on the vacuum suction. Use a pipette to drop 100 μL of precursor solution 2 onto the FTO conductive glass and immediately spin coat. Transfer the spin-coated FTO conductive glass to a 150°C hot plate for annealing for 15 minutes to form a perovskite film. After annealing, allow the FTO conductive glass to cool to room temperature. Set the spin coater parameters to: speed 4000 rpm, acceleration 3000, and spin coating time 30 seconds. Transfer the cooled FTO conductive glass to the spin coater turntable. Turn on the vacuum suction. Use a pipette to drop 50 μL of Spiro solution onto the FTO conductive glass. Lightly spread the solution and spin coat for 30 seconds. Move all the spin-coated FTO conductive glass to a drying oven for oxidation for 18 to 24 hours.

[0033] The cathode area of ​​the battery was scraped out on the oxidized FTO conductive glass according to the mask, and the Ag electrode was deposited on the FTO conductive glass using a magnetron sputtering deposition system to prepare a perovskite solar cell.

[0034] 2. Photovoltaic performance test of perovskite solar cells

[0035] The prepared perovskite solar cell was placed in a test fixture, and the light intensity of the solar simulator was set to AM = 1. The photoelectric performance of the cell was tested and analyzed using an electrochemical workstation, a computer and related software.

[0036] (1) JV curve test of perovskite solar cell

[0037] Attachment Figure 1 These are the JV curves for the control group and perovskite solar cells modified with different concentrations of 2,2'-azobisisobutylamidine dihydrochloride in this example. The curves show that the solar cells prepared with 2,2'-azobisisobutylamidine dihydrochloride exhibit superior photoelectric conversion performance. Specific performance parameters for the cells are shown in the table below.

[0038]

[0039] As shown in the table above, the short-circuit current and conversion efficiency of PSCs modified with 2,2'-azobisisobutylamidine dihydrochloride are significantly improved. The short-circuit current density of PSCs modified with 3 mg / mL 2,2'-azobisisobutylamidine dihydrochloride increases by 2 mA·cm -2 This will have important implications for the field of solar cells, where device performance is paramount, and provide an important reference for the industrialization of perovskite solar cells.

[0040] (2) Current stability curve test of perovskite solar cells modified with the control group and 2,2'-azobisisobutylamidine dihydrochloride interface

[0041] Attachment Figure 2 This is a current stability curve test of the perovskite solar cell interface modified with the control group and 3 mg / mL 2,2'-azobisisobutylamidine dihydrochloride in this example.

[0042] From the curve, it can be seen that the solar cell device with the ETL / perovskite layer interface modified by 2,2'-azobisisobutylamidine dihydrochloride has a higher short-circuit current, and the current remains stable after 400s of illumination under simulated sunlight of AM=1.5G.

[0043] 3. Phase analysis and testing of perovskite solar cells

[0044] (1) XRD test of the perovskite film modified with the control group and 2,2'-azobisisobutylamidine dihydrochloride interface

[0045] Attachment Figure 3 Figure 3 is the XRD pattern of the perovskite film modified at the interface of the control group and 3 mg / mL 2,2'-azobisisobutylamidine dihydrochloride in this example. Image analysis shows that the peak intensity of PbI2 of the perovskite film modified at the interface of 2,2'-azobisisobutylamidine dihydrochloride is significantly reduced, and the intensity of the perovskite peak is significantly increased, indicating that the perovskite modified at the interface of 2,2'-azobisisobutylamidine dihydrochloride has better crystallinity, reduces the PbI2 content at the interface, and improves the carrier transport capacity at the interface, thereby improving the efficiency of the perovskite solar cell.

[0046] For those skilled in the art, the present invention may be modified and improved without departing from the principles of the present invention, and these modifications and improvements also fall within the scope of protection of the present invention.

Claims

1. A 2,2'-azobisisobutylamidine dihydrochloride modified perovskite solar cell, characterized in that: The method mainly includes: spin coating a layer of 2,2'-azobisisobutylamidine dihydrochloride solution on the SnO2 electron transport layer of the prepared perovskite solar cell, and forming an electron transport layer modification layer through annealing.

2. The method according to claim 1, characterized in that The solvent of the 2,2'-azobisisobutylamidine dihydrochloride is ultrapure water.

3. The method according to claim 1, characterized in that The concentration of the 2,2'-azobisisobutylamidine dihydrochloride solution is 0.5-5 mg / mL.

4. The method according to claim 1, characterized in that The spin coating amount of the 2,2'-azobisisobutylamidine dihydrochloride solution is 40 to 60 μL.

5. The method according to claim 1, characterized in that The spin coating speed of the 2,2'-azobisisobutylamidine dihydrochloride solution is 2000-4000 rpm, and the spin coating time is 20-40 s.

6. The method according to claim 1, characterized in that The annealing temperature of the 2,2'-azobisisobutylamidine dihydrochloride solution is 120-150° C., and the annealing time is 15-30 minutes.

7. A SnO2 electron transport layer modified with 2,2'-azobisisobutylamidine dihydrochloride prepared according to the method of any one of claims 1 to 6.

8. A preparation process of a perovskite solar cell, characterized in that: The following steps are involved: Step 1: Deposit SnO2 electron transport layer on FTO / ITO conductive glass; Step 2: preparing a 2,2'-azobisisobutylamidine dihydrochloride modified layer on the SnO2 electron transport layer according to the method described in claims 1 to 5; Step 3: Preparation of FA on the SnO2 electron transport layer modified with 2,2'-azobisisobutylamidine dihydrochloride x MA y Cs 1-x-y PbI3 perovskite light absorbing layer; Step 4: Prepare a Spiro-OMeTAD hole transport layer and a metal Ag electrode on the perovskite light absorbing layer to obtain the perovskite solar cell.

9. The preparation method according to claims 1 to 8 can be modified and improved by a person skilled in the art without departing from the principles of the present invention, and such modifications and improvements also fall within the scope of protection of the claims of the present invention.

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