A method for depassivating perovskite surface defects using oxygen plasma irradiation

Abstract

The present invention discloses a method for depassivating the surface defects of perovskite by oxygen plasma irradiation, comprising the following steps: step 1, cleaning ITO conductive glass; step 2, spin coating PEDOT:PSS; step 3, spin coating perovskite solution; step 4, oxygen plasma treatment; step 5, annealing; step 6, observing the surface morphology; step 7, successively spin coating PCBM and BCP solution; step 8, silver plating. The experimental process of the present invention is simple to operate, that is, the perovskite film is irradiated by oxygen plasma, and oxygen can dissociate oxygen molecules into oxygen ion states after ignition treatment. These dissociated oxygen atoms can be embedded in the lattice of perovskite atoms to passivate the original defects of the perovskite film, thereby preparing a high-density, high-crystallinity, large-particle perovskite film. The present invention improves the efficiency of perovskite solar cells, saves energy, and reduces the cost of perovskite solar cells.

Description

Technical Field

[0001] The invention belongs to the field of perovskite solar cells, and specifically relates to a method for improving the surface morphology of a perovskite layer of a solar cell by utilizing oxygen plasma irradiation, and is suitable for passivating some inherent defects on the surface of the perovskite. Background Art

[0002] Hybrid organic-inorganic halide perovskite (HHPs) solar cells have attracted widespread attention from the scientific community due to their superior light absorption coefficient, long carrier diffusion length, and tunable band gap. The power conversion efficiency (PCE) of HHPs solar cells has reached 25.2%. However, there are a large number of defects in perovskite materials, which accelerate the degradation of perovskite materials and reduce the stability of perovskite solar cells. In order to further improve the efficiency and stability of HHPs solar cells, some researchers have proposed passivation strategies to reduce surface defects, such as introducing metal ions, functional molecules, and halide ions. The passivation treatment of perovskite films significantly improved the stability of HHPs solar cells.

[0003] The present invention uses ITO conductive glass as a template, uses a coating machine and a nitrogen glove box to spin-coat the perovskite solution, and then irradiates it with oxygen plasma. A constant temperature heating plate is used for annealing to obtain a high-density, high-crystallinity, large-particle perovskite film layer. In these perovskite films treated with oxygen plasma, oxygen can dissociate oxygen molecules into oxygen ion states after glow discharge treatment. These dissociated oxygen atoms can be embedded in the crystal lattice of perovskite atoms to passivate the original defects of the perovskite, providing a new solution for preparing high-performance and stable perovskite solar cells. Summary of the invention

[0004] Purpose of the invention: In order to solve the deficiencies of the prior art, the present invention provides a method for depassivating perovskite surface defects by oxygen plasma irradiation.

[0005] Technical solution: A method for depassivating perovskite surface defects by oxygen plasma irradiation, comprising the following steps:

[0006] Step 1: Clean the ITO conductive glass: ultrasonically clean it twice with acetone and anhydrous ethanol for 30 minutes each time, then blow it clean with nitrogen and set aside;

[0007] Step 2, spin coating PEDOT:PSS: In a nitrogen glove box, the treated ITO was spin coated with PEDOT:PSS solution on the ITO glass using a spin coater at a low speed of 1000 rpm / 5s and a high speed of 3000 rpm / 30s, and then annealed at 110°C for 30min;

[0008] Step 3: The amount of perovskite solution is 50ul, and the speed of the gelator is low speed 1500rpm / 20s and high speed 4000rpm / 40s, and it is spin-coated on the ITO glass. During the last 20s of spin coating, 120ul of chlorobenzene is added dropwise;

[0009] Step 4: Oxygen plasma treatment: Place the ITO conductive glass with the perovskite solution spin-coated in a SAOD-5D plasma cleaning machine, set the power to 70W, the oxygen flow rate to 0.2mL / min, and perform oxygen plasma treatment for 5s;

[0010] Step 5: Annealing: The treated conductive glass is annealed on a constant temperature heating plate at 110°C for 10 minutes;

[0011] Step 6: Observe the surface morphology: Place the oxygen plasma treated perovskite film into a scanning electron microscope (SEM) to observe the surface morphology;

[0012] Step 7, spin-coat PCBM and BCP solutions in sequence: In a nitrogen glove box, spin-coat the PCBM solution at a low speed of 1000rpm / 10s and a high speed of 2000rpm / 30s, and then anneal at 90°C for 10min; then spin-coat the BCP solution at a low speed of 1500rpm / 15s and a high speed of 2000rpm / 20s;

[0013] Step 8. Silver plating: Use tweezers to scrape off the perovskite layer on the ITO conductive glass common electrode, put the ITO into the template, use a vacuum evaporator to evaporate a 120nm thick silver film, and finally use a solar test system to detect the battery parameters.

[0014] As optimization: the specific formula of the present invention is as follows:

[0015] (1) Prepare a perovskite solution: Methylammonium iodide (MAI) and lead iodide are mixed in a molar ratio of 1:1 in a solution of 3:7 to prepare a perovskite solution, and heated and stirred at 60°C for more than 12 hours; wherein the methylammonium iodide (MAI) is 162.4 mg, and the lead iodide is 470.9 mg; the solution contains 700 ul of butyrolactone and 300 ul of dimethyl sulfoxide;

[0016] (2) Prepare a PCBM solution by mixing 20 mg PCBM with 1 mL chlorobenzene and heat and stir at 60 °C for 2 h;

[0017] (3) Mix BCP and anhydrous ethanol in a ratio of 1:1 and stir for 2 h; wherein the BCP is 2 mg and the anhydrous ethanol is 2 mL.

[0018] Beneficial effects: The specific advantages of the present invention are as follows:

[0019] 1. The experimental process of the present invention is simple to operate;

[0020] 2. The present invention can prepare high-density, high-crystallinity, large-particle perovskite films;

[0021] 3. The present invention passivates some inherent defects of perovskite itself;

[0022] 4. The present invention improves the efficiency of perovskite solar cells;

[0023] 5. The present invention saves energy and reduces the cost of perovskite solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the process flow of the present invention. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present invention will be described clearly and completely below so that those skilled in the art can better understand the advantages and features of the present invention, thereby making a clearer definition of the protection scope of the present invention. The embodiments described in the present invention are only a part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0026] Example

[0027] The specific formula of the present invention is as follows:

[0028] (1) Prepare a perovskite solution: Methylammonium iodide (MAI) and lead iodide are mixed in a molar ratio of 1:1 in a solution of 3:7 to prepare a perovskite solution, and heated and stirred at 60°C for more than 12 hours; wherein the methylammonium iodide (MAI) is 162.4 mg, and the lead iodide is 470.9 mg; the solution contains 700 ul of butyrolactone and 300 ul of dimethyl sulfoxide;

[0029] (2) Prepare a PCBM solution by mixing 20 mg PCBM with 1 mL chlorobenzene and heat and stir at 60 °C for 2 h;

[0030] (3) Mix BCP and anhydrous ethanol in a ratio of 1:1 and stir for 2 h; wherein the BCP is 2 mg and the anhydrous ethanol is 2 mL.

[0031] The specific operation steps of the present invention are as follows:

[0032] Step 1: Clean the ITO conductive glass: ultrasonically clean it twice with acetone and anhydrous ethanol for 30 minutes each time, then blow it clean with nitrogen and set aside;

[0033] Step 2, spin coating PEDOT:PSS: In a nitrogen glove box, the treated ITO was spin coated with PEDOT:PSS solution on the ITO glass using a spin coater at a low speed of 1000 rpm / 5s and a high speed of 3000 rpm / 30s, and then annealed at 110°C for 30min;

[0034] Step 3: The amount of perovskite solution is 50ul, and the speed of the gelator is low speed 1500rpm / 20s and high speed 4000rpm / 40s, and it is spin-coated on the ITO glass. During the last 20s of spin coating, 120ul of chlorobenzene is added dropwise;

[0035] Step 4: Oxygen plasma treatment: Place the ITO conductive glass with the perovskite solution spin-coated in a SAOD-5D plasma cleaning machine, set the power to 70W, the oxygen flow rate to 0.2mL / min, and perform oxygen plasma treatment for 5s;

[0036] Step 5: Annealing: The treated conductive glass is annealed on a constant temperature heating plate at 110°C for 10 minutes;

[0037] Step 6: Observe the surface morphology: Place the oxygen plasma treated perovskite film into a scanning electron microscope (SEM) to observe the surface morphology;

[0038] Step 7, spin-coat PCBM and BCP solutions in sequence: In a nitrogen glove box, spin-coat the PCBM solution at a low speed of 1000rpm / 10s and a high speed of 2000rpm / 30s, and then anneal at 90°C for 10min; then spin-coat the BCP solution at a low speed of 1500rpm / 15s and a high speed of 2000rpm / 20s;

[0039] Step 8. Silver plating: Use tweezers to scrape off the perovskite layer on the ITO conductive glass common electrode, put the ITO into the template, use a vacuum evaporator to evaporate a 120nm thick silver film, and finally use a solar test system to detect the battery parameters.

[0040] like Figure 1 The normally prepared perovskite film shown in the figure only needs to be spin-coated by a coater in a nitrogen glove box and annealed on a constant temperature heating plate. However, oxygen plasma irradiation requires that the perovskite film be irradiated by an oxygen plasma machine after spin coating, and then annealed on a constant temperature heating plate.

[0041] As can be seen from the two process diagrams, the perovskite precursor film irradiated by oxygen plasma has the characteristics of high crystallinity, high density, and large particles. At the same time, the power conversion efficiency (PCE) of the perovskite solar cell has also been greatly improved, from the normal 10.24% to 13.84%.

Claims

1. A method for depassivating perovskite surface defects by oxygen plasma irradiation, characterized in that: The steps include: Step 1: Clean the ITO conductive glass: ultrasonically clean it twice with acetone and anhydrous ethanol for 30 minutes each time, then blow it clean with nitrogen and set aside; Step 2, spin coating PEDOT:PSS: In a nitrogen glove box, the treated ITO was spin coated with PEDOT:PSS solution on the ITO glass using a spin coater at a low speed of 1000 rpm / 5s and a high speed of 3000 rpm / 30s, and then annealed at 110°C for 30min; Step 3, spin coating perovskite solution: the amount of perovskite solution is 50ul, the speed of the gelator is low speed 1500rpm / 20s, high speed 4000rpm / 40s, spin coating on the ITO glass, in the last 20s of spin coating, add 120ul chlorobenzene; Step 4: Oxygen plasma treatment: Place the ITO conductive glass with the perovskite solution spin-coated in a SAOD-5D plasma cleaning machine, set the power to 70W, the oxygen flow rate to 0.2mL / min, and perform oxygen plasma treatment for 5s; Step 5: Annealing: The treated conductive glass is annealed on a constant temperature heating plate at 110°C for 10 minutes; Step 6: Observe the surface morphology: Place the oxygen plasma treated perovskite film into a scanning electron microscope (SEM) to observe the surface morphology; Step 7, spin-coat PCBM and BCP solutions in sequence: In a nitrogen glove box, spin-coat the PCBM solution at a low speed of 1000rpm / 10s and a high speed of 2000rpm / 30s, and then anneal at 90°C for 10min; then spin-coat the BCP solution at a low speed of 1500rpm / 15s and a high speed of 2000rpm / 20s; Step 8. Silver plating: Use tweezers to scrape off the perovskite layer on the ITO conductive glass common electrode, put the ITO into the template, use a vacuum evaporator to evaporate a 120nm thick silver film, and finally use a solar test system to detect the battery parameters.

2. The method for depassivating perovskite surface defects by oxygen plasma irradiation according to claim 1, characterized in that: The specific formula is as follows: (1) Prepare a perovskite solution: Methylammonium iodide (MAI) and lead iodide are mixed in a molar ratio of 1:1 in a solution of 3:7 to prepare a perovskite solution, and heated and stirred at 60°C for more than 12 hours; wherein the methylammonium iodide (MAI) is 162.4 mg, and the lead iodide is 470.9 mg; the solution contains 700 ul of butyrolactone and 300 ul of dimethyl sulfoxide; (2) Prepare a PCBM solution by mixing 20 mg PCBM with 1 mL chlorobenzene and heat and stir at 60 °C for 2 h; (3) Mix BCP and anhydrous ethanol in a ratio of 1:1 and stir for 2 h; wherein the BCP is 2 mg and the anhydrous ethanol is 2 mL.

Images