Perovskite precursor solution based on aspartame passivator and preparation method and application thereof

Abstract

The invention relates to the technical field of photovoltaics, and discloses a perovskite precursor solution based on an aspartame passivator, and a preparation method and application thereof. The perovskite precursor solution comprises a perovskite component, a solvent and a passivator, the passivator is sodium cyclohexane sulfamate, the chemical formula of the perovskite is Csx (FAyMA1-y) 1-xPb (IzBr1-z) 3, x is greater than or equal to 0 and less than or equal to 1, y is greater than or equal to 0 and less than or equal to 1, and z is greater than or equal to 0 and less than or equal to 1. The invention also provides a method for preparing a perovskite thin film by using the solution, and the thin film is applied to a trans-structured perovskite solar module. The assembly comprises a transparent conductive substrate, and a hole transport layer, the perovskite thin film, an electron transport layer, a hole blocking layer and a metal electrode which are stacked on the transparent conductive substrate in sequence.

Description

A perovskite precursor solution based on saccharin passivator, its preparation method and application Technical Field

[0001] This invention relates to the field of perovskite solar cell technology, specifically to a perovskite precursor solution based on saccharin passivating agent, its preparation method, and its application. Background Technology

[0002] Perovskite solar cells have seen rapid development in recent years due to their tunable bandgap and low-cost fabrication. Currently, the efficiency of laboratory-fabricated organic-inorganic hybrid perovskite solar cells has exceeded 27%. However, because perovskite materials are highly sensitive to the environment, polycrystalline perovskite films often contain various defects such as iodine and lead vacancies, which limit the device's efficiency and long-term stability. Furthermore, as the film area increases during process scale-up, the number of defects further increases, leading to a further decrease in module efficiency and stability. Using passivating agents to regulate perovskite crystallization, enhance crystallinity, and reduce the defect state density to obtain high-quality, large-area perovskite films is a common control method. However, most passivating materials have complex synthesis processes, are expensive, and offer limited passivation effects.

[0003] This invention proposes a perovskite solar module based on the passivation of the synthetic sweetener cyclamate. Cyclamate is composed of cyclohexane, imino groups, sulfonic acid groups, and sodium ions. The sulfonic acid groups can pass through Pb... O-coordination anchors uncoordinated Pb ions in situ, while imino groups form hydrogen bonds with halogens, regulating perovskite crystallization, reducing perovskite defect density, and forming high-quality, large-area perovskite films. Perovskite modules passivated with cyclamate exhibit significantly higher photoelectric conversion efficiency than those without cyclamate passivation, and their stability is also significantly improved. Cyclamate is widely used in the food industry, and its use as a perovskite passivating agent is not only readily available but also inexpensive. Summary of the Invention

[0004] In view of this, the present invention provides a perovskite precursor solution based on cyclamate passivating agent, its preparation method, and its application. The present invention involves adding synthetic cyclamate (sodium cyclohexanesulfonate) to a perovskite precursor solution, followed by slit coating to prepare a perovskite light-absorbing layer film. The sulfonic acid groups of cyclamate can pass through Pb... O-coordination anchors uncoordinated Pb ions in situ, while imino groups form hydrogen bonds with halogens in the perovskite. This effectively inhibits ion migration, regulates perovskite crystallization, improves perovskite film quality, and reduces internal defects in perovskite materials. It enables low-cost passivation of perovskite films and the fabrication of perovskite solar modules with better photoelectric performance and stability.

[0005] The technical solution provided by this invention is as follows: Firstly, this invention provides a perovskite precursor solution comprising a perovskite component, a solvent, and a passivating agent, wherein the passivating agent is sodium cyclohexanesulfonate; the perovskite has the chemical formula Cs. x (FA y MA 1-y ) 1-x Pb(I z Br 1-z )3, where 0≤x≤1, 0≤y≤1, 0≤z≤1.

[0006] Preferably, the chemical formula of the perovskite is Cs. 0.05 FA 0.95 PbI3 or Cs 0.05 MA 0.1 FA 0.85 PbI3.

[0007] In the perovskite precursor solution, the concentration of the perovskite component is 1.0-1.5 M. The molar amount of sodium cyclohexanesulfonate is 0.3% to 1.5% of the molar amount of the perovskite component.

[0008] The solvent is a mixture of N,N-dimethylformamide and N-methylpyrrolidone in a volume ratio of 8:1 to 11:1.

[0009] Secondly, the present invention provides a method for preparing a perovskite precursor solution, comprising the following steps: Step 1, dissolving perovskite raw material in a mixed solvent and stirring to obtain a basic precursor solution; Step 2, adding sodium cyclohexanesulfonate as a passivating agent to the basic precursor solution and stirring to mix evenly to obtain the perovskite precursor solution; the chemical formula of the perovskite component is Cs. x (FA y MA 1-y ) 1-x Pb(I z Br 1-z )3, where 0≤x≤1, 0≤y≤1, 0≤z≤1.

[0010] In the perovskite precursor solution, the concentration of the perovskite component is 1.0-1.5 M. The molar amount of sodium cyclohexanesulfonate is 0.1% to 1% of the molar amount of the perovskite component.

[0011] The solvent is a mixture of N,N-dimethylformamide and N-methylpyrrolidone in a volume ratio of 8:1 to 11:1.

[0012] Thirdly, the present invention provides a perovskite thin film, which is prepared by coating and annealing a perovskite precursor solution as described above.

[0013] The coating is performed using a slot coating method; the process parameters for slot coating are: the slot between the doctor blade and the substrate is 200-250 μm, and the coating speed is 10-20 mm / s.

[0014] The annealing process is performed at a temperature of 100-150 ℃ for 10-30 min.

[0015] The thickness of the perovskite film is 450 nm to 550 nm.

[0016] Fourthly, the present invention provides a perovskite solar cell module, comprising a transparent conductive substrate and a hole transport layer, a perovskite thin film as described above, an electron transport layer, a hole blocking layer and a metal electrode sequentially stacked on the transparent conductive substrate.

[0017] The substrate is FTO glass or ITO glass.

[0018] In step (2), the hole transport layer is Spiro-OMeTAD or NiO. n One or more of PTAA, PEDOT:PPS materials, with a hole transport layer thickness of 20-50 nm.

[0019] NiO n For non-stoichiometric nickel oxide, n>1; the actual prepared nickel oxide films are often NiO, but rather oxygen vacancies or nickel vacancies, and their composition varies between NiO and Ni2O3.

[0020] The electron transport layer includes C 60 TiO2, SnO2, CeO m One or more of PCBM; the thickness of the electron transport layer is 35-50nm.

[0021] CeO m In this context, m represents oxygen vacancies, and the value of m ranges from 0.5 to 1.8.

[0022] The hole-blocking layer comprises copper bath or bis[2-(diphenylphosphine)phenyl] ether oxide; the hole-blocking layer has a thickness of 5-10 nm; the metal electrode is made of Al, Cu, Ag or Au, and has a thickness of 80 nm to 150 nm.

[0023] Fifthly, the present invention provides a method for preparing a perovskite solar module, comprising the following steps: (1) providing a transparent conductive substrate; (2) preparing a hole transport layer on the transparent conductive substrate; (3) coating the hole transport layer with the perovskite precursor solution as described above, and annealing it to form a perovskite thin film as a perovskite active layer; (4) sequentially preparing an electron transport layer, a hole blocking layer and a metal electrode on the perovskite active layer.

[0024] In step (2), the hole transport layer is Spiro-OMeTAD or NiO. n One or more of PTAA, PEDOT:PPS materials, with a hole transport layer thickness of 20-50 nm.

[0025] Preferably, in step (2), the hole transport layer is NiO. n The material is deposited by magnetron sputtering in an oxygen-containing atmosphere. After sputtering, it is heat-treated at a temperature of 250-350℃ for 30-90 minutes.

[0026] NiO n For non-stoichiometric nickel oxide, n>1; the actual prepared nickel oxide films are often NiO, but rather oxygen vacancies or nickel vacancies, and their composition varies between NiO and Ni2O3.

[0027] In step (3), the perovskite precursor solution is coated using a slot coating method, with a slot between the scraper and the substrate of 200-250 μm and a coating speed of 10-20 mm / s. The annealing treatment is carried out at a temperature of 100-150 ℃ for 10-30 min.

[0028] In step (4), the electron transport layer and the hole blocking layer are prepared by vacuum evaporation. The electron transport layer is C60 with a thickness of 35-50 nm; the hole blocking layer is BCP with a thickness of 5-10 nm.

[0029] In step (4), the metal electrode is a copper electrode, which is prepared by vacuum evaporation and has a thickness of 80-150 nm.

[0030] The fabrication method of the perovskite solar module also includes a laser patterning process, specifically comprising the following steps: P1 scribing: before or after fabricating the hole transport layer, scribing is performed on the transparent conductive substrate to define independent sub-electrodes; P2 scribing: after fabricating the hole blocking layer, scribing is performed on the hole blocking layer, electron transport layer, perovskite active layer, and hole transport layer to expose the underlying transparent conductive substrate; P3 scribing: after fabricating the metal electrode, scribing is performed on the metal electrode, hole blocking layer, electron transport layer, perovskite active layer, and hole transport layer to achieve series connection between sub-cells.

[0031] The P2 and P3 scribing processes were performed using a green picosecond laser.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The present invention effectively regulates the orderly growth of perovskite by adding cyclamate as a passivating agent to the perovskite precursor solution, promotes the conversion of lead iodide, ammonium salts, etc. into perovskite crystals, and prepares perovskite thin films with larger grains, fewer grain boundaries and smoother surfaces.

[0033] (2) The ionic liquid passivator cyclamate provided by the present invention contains sulfonic acid group and imino group, which can anchor uncoordinated Pb ions, form hydrogen bonds with halogens, inhibit ion migration, passivate the defect state of perovskite material, and significantly improve the quality of perovskite film.

[0034] (3) The perovskite solar module passivated by cyclamate provided by the present invention can achieve a photoelectric conversion efficiency of more than 19%, which is 16.9% higher than that of undoped devices.

[0035] (5) The perovskite solar module without encapsulation and passivated by cyclamate provided by the present invention maintains an efficiency of more than 85% of the initial efficiency after being stored for 600 hours under environmental conditions (room temperature, relative humidity 20%-40%).

[0036] (6) The perovskite solar module preparation process provided by the present invention is simple, efficient and stable, with high reliability and repeatability, and has the prospect of large-area expansion and commercial development.

[0037] (7) The perovskite solar module passivator cyclamate provided by the present invention is inexpensive, widely available, requires little usage and has significant effects, and has the prospect of commercial development. Attached Figure Description

[0038] Other features, objects and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 shows the long-term stability of the unencapsulated component (Example 2, Comparative Example 1) under environmental conditions (room temperature, relative humidity 20%-40%). Detailed Implementation

[0039] The present invention will be described in detail below with reference to embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several adjustments and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0040] Example 1, Step 1: Preparation of the basic perovskite solution. Lead iodide (PbI2), formamidinium iodide (FAI), and cesium iodide (CsI) were used as perovskite raw materials, and CsI was prepared according to the stoichiometric ratio. 0.05 FA 0.95PbI3 was weighed and dissolved in a mixed solvent consisting of N,N-dimethylformamide (DMF) and N-methyl-2-pyrrolidone (NMP), wherein the volume ratio of DMF to NMP was 9:1; the mixture was stirred at room temperature for 4 hours to form a clear basic precursor solution. In this solution, the target perovskite Cs... 0.05 FA 0.95 The concentration of PbI3 was 1.0 M (in Pb²). + (ion concentration meter).

[0041] Step 2: Introduce sodium cyclohexylsulfamate (cyclamate) as a passivating agent into the basic precursor solution, and continue stirring for 30 minutes to ensure that the passivating agent is completely dissolved and uniformly dispersed, thus obtaining the perovskite precursor solution; wherein, the molar amount of cyclamate passivating agent is equal to the molar amount of the perovskite component (Cs). 0.05 FA 0.95 0.5% of the molar amount of PbI3; cyclamate (sodium cyclohexanesulfonate) passivating agent, chemical formula C6H 12 NNaO3S, structural formula is: .

[0042] Example 2, Step 1: Preparation of the basic perovskite solution. Lead iodide (PbI2), formamidinium iodide (FAI), cesium iodide (CsI), and methylamine iodide (MAI) were used as perovskite raw materials, and CsI was prepared according to the stoichiometric ratio. 0.05 MA 0.1 FA 0.85 PbI3 was weighed and dissolved in a mixed solvent consisting of N,N-dimethylformamide (DMF) and N-methyl-2-pyrrolidone (NMP), wherein the volume ratio of DMF to NMP was 8:1; the mixture was stirred at room temperature for 4 hours to form a clear basic precursor solution. In this solution, the target perovskite Cs... 0.05 MA 0.1 FA 0.85 The concentration of PbI3 was 1.0 M (in Pb²). + (ion concentration meter).

[0043] Step 2: Introduce sodium cyclohexylsulfamate (cyclamate) as a passivating agent into the basic precursor solution, and continue stirring for 30 minutes to ensure that the passivating agent is completely dissolved and uniformly dispersed to obtain a perovskite precursor solution; wherein, the molar amount of cyclamate passivating agent is 0.5% of the molar amount of the perovskite component.

[0044] Comparative Example 1: The difference between this comparative example and the example is that no cyclamate deactivator (sodium cyclohexanesulfonate) is added in step 1.

[0045] The difference between Comparative Example 2 and the Example is that the cyclamate deactivator (sodium cyclohexanesulfonate) in step 1 is replaced with (KCl).

[0046] The difference between Comparative Example 3 and the Example is that the molar amount of cyclamate passivating agent (sodium cyclohexanesulfonate) in step 1 is 2% of the molar amount of the perovskite component.

[0047] The difference between Comparative Example 4 and the Example is that the molar amount of cyclamate passivating agent (sodium cyclohexanesulfonate) in step 1 is 0.1% of the molar amount of the perovskite component.

[0048] The difference between Comparative Example 5 and the Example is that in step 1, the cyclamate passivating agent (sodium cyclohexanesulfonate) is replaced with sodium dodecylbenzenesulfonate (SDBS), and its molar amount is 0.5% of the molar amount of the perovskite component.

[0049] The performance test examples applied the perovskite thin films prepared in each comparative example and embodiment to perovskite solar cells. The perovskite solar cell module was an inverted structure, consisting of, from top to bottom: an FTO substrate and a NiO layer. n The substrate consists of a hole transport layer, a perovskite active layer, a C60 electron transport layer, a BCP hole blocking layer, and a metal electrode. The preparation steps are as follows: Step 1: Substrate cleaning and treatment. Take FTO conductive glass and ultrasonically clean the surface sequentially with a cleaning agent, deionized water, and anhydrous ethanol. Each cleaning session lasts 30 minutes. After cleaning, dry the substrate and subject the clean substrate to UV-ozone treatment for 25 minutes.

[0050] Step 2: P1 laser scribing uses a red nanosecond laser to perform P1 laser scribing on the processed FTO substrate, uniformly dividing the large-area FTO electrode into multiple independent sub-electrodes.

[0051] Step 3: Fabrication of the hole transport layer. The scribed substrate is transferred to the magnetron sputtering chamber, and the chamber background vacuum is evacuated to 8 × 10⁻⁶. -4 When the pressure is below Pa, a mixture of argon and oxygen is introduced into the cavity, with oxygen accounting for 15% of the total gas mass flow rate, and the working pressure is 2.4 Pa. A DC power supply is used, set to 150 W, to sputter a Ni metal target and deposit a nickel layer on the FTO surface. Subsequently, the sample is heat-treated at 300°C in air for 60 minutes, ultimately forming a 40 nm thick nickel oxide (NiO) layer. x Hole transport layer.

[0052] Step 4: Preparation of the perovskite active layer (perovskite thin film) A perovskite thin film was then prepared on the prepared hole transport layer. The perovskite thin film was prepared using a slit coating method with the following parameters: 220 μm between the doctor blade and the substrate, and a coating speed of 15 mm / s. After coating with the perovskite precursor solutions prepared in each example and comparative example, the wet film was vacuum-crystallized and then annealed at 120°C for 20 minutes to finally form a perovskite active layer with a thickness of 500 nm.

[0053] Step 5: Fabrication of the electron transport layer and hole blocking layer. On the perovskite active layer, the electron transport layer and hole blocking layer are sequentially deposited by vacuum evaporation; firstly, on an 8×10⁻⁶ layer… -4 Under intrinsic vacuum of Pa, a 35 nm thick C60 layer was deposited as an electron transport layer at a rate of 1.2 Å / s. Subsequently, without breaking the vacuum, a 5 nm thick BCP layer was deposited as a hole blocking layer at a rate of 0.8 Å / s.

[0054] Step 6: P2 laser scribing After the functional layer deposition is completed, a green picosecond laser is used to perform P2 laser scribing to remove the hole blocking layer, electron transport layer / perovskite layer / hole transport layer, leaving the FTO layer.

[0055] Step 7: P2.5 Laser Edge Cleaning After P2 laser scribing, a red nanosecond laser is used for P2.5 laser edge cleaning. The hole blocking layer, electron transport layer, perovskite layer, and hole transport layer in a 1 cm area on each side of the FTO substrate are removed along the P1 and P2 scribing directions, leaving only FTO.

[0056] Step 7: Fabrication of the metal electrode layer. After scribing P2 and P2.5, a 1cm wide high-temperature adhesive tape is attached to the edge of the FTO substrate along the scribing perpendicular to P1 and P2. The metal electrode is then fabricated by vacuum evaporation. (8×10) -4 Under intrinsic vacuum of Pa, a copper (Cu) electrode of approximately 100 nm thickness was deposited at an evaporation rate of 4 Å / s.

[0057] Step 8: P3 laser scribing uses a green picosecond laser to scribing the deposited copper metal electrode, removing the metal electrode layer / hole blocking layer, electron transport layer / perovskite layer / hole transport layer of the adjacent cell, leaving FTO.

[0058] Step 9: P4 laser edge cleaning uses a red nanosecond laser to clean the edges of the area covered by high-temperature tape, removing all the film layers covering it until it reaches the glass.

[0059] The photoelectric conversion efficiency of the fabricated perovskite photovoltaic modules was tested under simulated standard sunlight using a steady-state solar cell module simulator (Shaanxi Zhongsen GSIV-22A0606). Unencapsulated perovskite solar modules were stored under environmental conditions (room temperature, relative humidity 20%-40%), and their photoelectric efficiency was tested every 75 hours to continuously monitor their stability.

[0060] The test results are shown in Table 1 and Figure 1: Table 1 Photoelectric data of each embodiment and comparative example

[0061] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that these are merely illustrative examples, and any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A perovskite precursor solution, characterized in that, It comprises a perovskite component, a solvent, and a passivating agent, wherein the passivating agent is sodium cyclohexanesulfonate; the perovskite has the chemical formula Cs. x (FA y MA 1-y ) 1-x Pb(I z Br 1-z )3, where 0≤x≤1, 0≤y≤1, 0≤z≤1.

2. The perovskite precursor solution according to claim 1, characterized in that, In the perovskite precursor solution, the concentration of the perovskite component is 1.0-1.5 M; The molar amount of sodium cyclohexanesulfonate is 0.3 to 1.5% of the molar amount of the perovskite component.

3. The perovskite precursor solution according to claim 1, characterized in that, The solvent is a mixture of N,N-dimethylformamide and N-methylpyrrolidone in a volume ratio of 8:1 to 11:

1.

4. A method for preparing a perovskite precursor solution, characterized in that, The process includes the following steps: Step 1, dissolving the perovskite raw material in a mixed solvent and stirring to obtain a basic precursor solution; Step 2, adding sodium cyclohexanesulfonate as a passivating agent to the basic precursor solution and stirring until homogeneous to obtain the perovskite precursor solution; wherein the chemical formula of the perovskite component is Cs. x (FA y MA 1-y ) 1-x Pb(I z Br 1-z )3, where 0≤x≤1, 0≤y≤1, 0≤z≤1.

5. A perovskite thin film, characterized in that, The perovskite precursor solution as described in any one of claims 1-3 is prepared by coating and annealing.

6. A perovskite solar module, characterized in that, It includes a transparent conductive substrate and a hole transport layer, a perovskite thin film as described in claim 5, an electron transport layer, a hole blocking layer and a metal electrode, which are sequentially stacked on the transparent conductive substrate.

7. The perovskite solar module according to claim 6, characterized in that, The hole transport layer is Spiro-OMeTAD, NiO n One or more combinations of PTAA, PEDOT:PPS materials, with a hole transport layer thickness of 20-50 nm; and / or, the electron transport layer includes C 60 TiO2, SnO2, CeO m One or more of PCBM; the electron transport layer has a thickness of 35-50 nm; and / or, the hole blocking layer comprises copper bath or bis[2-(diphenylphosphine)phenyl] ether oxide; the hole blocking layer has a thickness of 5-10 nm; and / or, the metal electrode is made of Al, Cu, Ag or Au, and has a thickness of 80 nm-150 nm.

8. A method for preparing a perovskite solar module, characterized in that, The steps include: (1) providing a transparent conductive substrate; (2) A hole transport layer is prepared on the transparent conductive substrate; (3) Coating the hole transport layer with the perovskite precursor solution as described in any one of claims 1 to 3, and annealing it to form a perovskite film as the perovskite active layer; (4) Sequentially preparing an electron transport layer, a hole blocking layer and a metal electrode on the perovskite active layer.

9. The preparation method according to claim 8, characterized in that, In step (3), the perovskite precursor solution is coated using a slot coating method, with a slot between the scraper and the substrate of 200-250 μm and a coating speed of 10-20 mm / s. The annealing treatment is carried out at a temperature of 100-150 ℃ for 10-30 min.

10. The preparation method according to claim 8, characterized in that, In step (4), the electron transport layer and the hole blocking layer are prepared by vacuum evaporation. The electron transport layer is C60 with a thickness of 35-50 nm; the hole blocking layer is BCP with a thickness of 5-10 nm.

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