Neostigmine bromide passivator-based perovskite active layer film and preparation method and application thereof

Abstract

The invention belongs to the technical field of perovskite solar cell interface engineering passivation, and relates to a perovskite active layer film based on a neostigmine bromide passivator and a preparation method and application thereof. According to the preparation method, a solution method is adopted for operation, and neostigmine bromide is introduced to the perovskite thin film as a passivating agent, so that surface and interface defects are reduced, and non-radiative recombination is inhibited. Besides, energy band arrangement at the interface can be improved, charge extraction can be enhanced, and charge accumulation can be reduced, so that the stability and charge transmission performance of the perovskite thin film are improved, the quality of the perovskite active layer thin film is improved, the performance of the perovskite solar cell is improved, and a new way is provided for realizing the efficient and stable perovskite solar cell.

Description

Technical Field

[0001] The invention belongs to the technical field of interface engineering passivation of perovskite solar cells and discloses a perovskite active layer film based on a neostigmine bromide passivator and a preparation method and application thereof. Technical Background

[0002] Carbon emissions from fossil fuels have been rising over the past decade. In 2024 alone, global carbon dioxide emissions will reach 41.6 billion tons, up from 40.6 billion tons last year. Most of the carbon emissions come from burning energy sources such as coal, oil and natural gas. Faced with this grim situation, reducing carbon emissions is urgent to avoid the dangerous effects of climate change. Solar energy has the advantages of abundant reserves, cleanness and pollution-free, and is one of the new energy sources that countries around the world are focusing on developing. Among them, perovskite solar cells (PSCs) are expected to play an important role in the future energy field due to their low manufacturing cost and high efficiency, but the challenges faced by commercial-scale solution preparation of PSCs include the use of harmful solvents, the cost of maintaining controlled atmospheric conditions, and the inherent instability in PSCs.

[0003] The defects in perovskite films mainly include lattice defects, interface defects and surface defects, which seriously restrict the improvement of carrier transport performance and stability of perovskite devices. Therefore, it is very important to reduce perovskite defects to form high-quality film morphology, optimize the entire device structure and the effective contact of each layer interface to obtain efficient and stable perovskite solar cells. Summary of the invention

[0004] The present invention aims to improve the quality of perovskite polycrystalline film by optimizing the upper surface of perovskite film, optimize the interface contact between perovskite and hole transport layer, and realize the improvement of efficiency and stability of perovskite solar cells. Currently, commonly used organic passivation molecules can usually only bind to a single active site on the surface of perovskite, and the binding ability is weak. The present invention provides a neostigmine bromide with multiple active sites as a passivator for use in the passivation of perovskite film. In order to reduce the voids at the grain boundaries of the perovskite film, thereby reducing the generation of surface defect states, the effect of improving the quality of the perovskite film is achieved, and the charge extraction speed in the device is increased, thereby improving the device performance, providing ideas for the development of efficient passivation molecules on the perovskite surface and the preparation of high-performance perovskite photovoltaic devices. And the neostigmine bromide passivator can reduce the voids at the grain boundaries of the perovskite film, thereby reducing the generation of surface defect states. The specific mechanism is: the carbonyl carbon C=O in the neostigmine bromide passivator can bind to the uncoordinated Pb in the perovskite. 2+ The quaternary ammonium group binds to the anion site of the perovskite through electrostatic attraction, and the dual active sites have a strong ability to bind to the perovskite. After treatment with neostigmine bromide, the hydrophobicity of the perovskite surface is enhanced, thereby enhancing the stability of the battery device under humid conditions.

[0005] Furthermore, a perovskite active layer film based on a neostigmine bromide passivator includes a perovskite active layer and a passivation layer, wherein the passivation layer is located on the surface of the perovskite active layer, and the passivation layer is composed of neostigmine bromide.

[0006] Furthermore, the method for preparing the perovskite film based on the neostigmine bromide passivator comprises the following steps:

[0007] The passivation molecule is first dissolved in a solvent to obtain a precursor solution of the passivation molecule. The precursor solution is coated on the surface of the perovskite active layer by a solution processing method such as spin coating, and dried to obtain a perovskite film based on a neostigmine bromide passivator.

[0008] Furthermore, the solvent is isopropanol or ethanol.

[0009] Furthermore, the concentration of the passivation molecule in the precursor solution is 0.5 mg / mL to 2 mg / mL, and based on the size of the conductive glass substrate: 1.6 cm*2.5 cm, the amount of the spin-coated passivation molecule solution is 25 μL.

[0010] Preferably, the concentration of the passivation molecule solution is 1 mg / mL to 1.5 mg / mL.

[0011] Furthermore, the passivation molecule is neostigmine bromide.

[0012] Furthermore, the coating is performed by spin coating; the spin coating parameters are as follows: spin coating speed 3000-5000 rpm, spin coating time 30 s.

[0013] Furthermore, the composition of the perovskite active layer is (FAPbI3) 0.95 (MAPbBr3) 0.05 .

[0014] Furthermore, a perovskite solar cell comprising the above-mentioned perovskite film based on neostigmine bromide passivator.

[0015] Furthermore, the perovskite solar cell device is composed of, from bottom to top, a conductive substrate, an electron transport layer, a perovskite active layer, a hole transport layer, and a metal electrode, and the perovskite active layer is the above-mentioned perovskite film based on neostigmine bromide passivator.

[0016] Furthermore, the conductive substrate is ITO (indium tin oxide) glass or FTO (fluorine-doped tin oxide) glass or ITO / PEN (polyethylene naphthalate) flexible conductive substrate or ITO / PET (polyethylene terephthalate) flexible conductive substrate, etc.

[0017] Furthermore, the electron transport layer material is tin dioxide (SnO2).

[0018] Furthermore, the hole transport layer is prepared by spin coating a Spiro-OMeTAD chlorobenzene (CB) solution to which lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI), FK209 Co (III) and 4-tert-butylpyridine (T-BP) are added.

[0019] Furthermore, the metal electrode is gold (Au) or silver (Ag) with a thickness of 80-100 nm.

[0020] The advantages of the present invention are:

[0021] Neostigmine bromide passivator has multiple active sites in the molecule, which can passivate (FAPbI3) 0.95 (MAPbBr3) 0.05 The system is an organic-inorganic hybrid perovskite cell surface, which reduces the gaps at the grain boundaries of the perovskite film, thereby reducing the generation of surface defects, achieving the effect of improving the quality of the perovskite film and increasing the charge extraction speed in the device, thereby improving the device performance. Specifically: the carbonyl carbon C=O in the neostigmine bromide passivator can react with the uncoordinated Pb in the perovskite 2+ The quaternary ammonium group is coordinated with the anion site of the perovskite through electrostatic attraction, and there is a strong interaction force between the dual active sites and the perovskite. After introducing neostigmine bromide as a passivating agent on the perovskite film, non-radiative recombination is inhibited, and the energy band arrangement at the interface can be improved, charge extraction is enhanced, and charge accumulation is reduced, thereby improving the stability of the perovskite film and the charge transfer performance. In addition, after treatment with neostigmine bromide, the hydrophobicity of the perovskite surface is enhanced, thereby enhancing the stability of the battery device under humid conditions. The optimal photoelectric conversion efficiency (PCE) of the perovskite solar cell treated with neostigmine bromide in the present invention is 24.39%, the open circuit voltage is 1.17V, and the short circuit current is 25.78mA / cm 2 , the filling factor is 81.48%, and this passivation strategy can simultaneously improve the efficiency, environmental stability, thermal stability, light stability and mechanical stability of perovskite solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram showing the device structure of the perovskite solar cell in Example 1 of the present invention;

[0023] Figure 2 4 shows the device structure of the flexible perovskite solar cell in Example 2 of the present invention;

[0024] Figure 3 Scanning electron microscope images of perovskite cells passivated with (1.5 mg / mL) / without neostigmine bromide in Example 1 of the present invention, wherein (a) is with neostigmine bromide, and (b) is without neostigmine bromide;

[0025] Figure 4 The JV curves of the perovskite cell passivated with neostigmine bromide at different concentrations in Example 1 of the present invention are shown;

[0026] Figure 5 The water contact angle test of the perovskite cell with (1.5 mg / mL) / without neostigmine bromide passivation in Example 1 is shown;

[0027] Figure 6 The JV curves of the perovskite cell with (1.5 mg / mL) / without neostigmine bromide passivation in Example 1 of the present invention are shown;

[0028] Figure 7 JV curves of flexible perovskite cells with and without neostigmine bromide passivation in Example 2 of the present invention;

[0029] Figure 8 It shows the thermal stability performance comparison of the perovskite battery with (1.5 mg / mL) and without neostigmine bromide passivation in Example 1 of the present invention;

[0030] Fig. 9 The illumination (100 mW / cm2) of the perovskite cell with (1.5 mg / mL) / without neostigmine bromide passivation in Example 1 of the present invention is shown in FIG. 2 , AM1.5G) stability test comparison;

[0031] Fig.10 It shows the mechanical stability test comparison of the perovskite cell with (1.5 mg / mL) / without neostigmine bromide passivation in Example 1 of the present invention. DETAILED DESCRIPTION

[0032] The present invention is described in detail below in conjunction with the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0033] Example 1

[0034] A method for preparing a perovskite solar cell comprising a neostigmine bromide passivation layer, the steps being as follows:

[0035] (1) Cleaning of the conductive substrate: The conductive substrate (ITO (FTO) / glass) is ultrasonically cleaned for 20 min using a conductive glass cleaning agent, deionized water, acetone, isopropyl alcohol, and alcohol in sequence. After cleaning, it is placed in an oven for drying for later use; the conductive substrate is ITO glass.

[0036] (2) Preparation of electron transport layer: Tin oxide nanocrystal solution (15 wt%) was dissolved in deionized water at a dilution ratio of 1:3, and after cold water ultrasonication for 15 min, filtered with a 0.45 μm polyethersulfone filter, 100 μL was spin-coated on clean ITO glass (ITO glass was ozone-treated for 20 min before spin coating), with a spin coating speed of 3000 rpm, an acceleration of 500 rpm / s, and a spin coating time of 45 s. Then annealed at 150°C for 30 min.

[0037] (3) Preparation of perovskite active layer: After treating the electron transport layer obtained in step 2 with a UV ozone generator for 25 minutes, the perovskite precursor solution was spin-coated on the surface of the electron transport layer. The first stage speed was 1000 rpm, the acceleration was 2000 rpm / s, and the time was 10 seconds. The second stage speed was 5000 rpm, the acceleration was 2000 rpm / s, and the spin coating time was 30 seconds. 110 μL of chlorobenzene was added at 10 seconds in the second stage. After the spin coating was completed, it was placed on a heating table and heated at 100°C for 60 minutes. The perovskite precursor solution was prepared by dissolving 0.2408 g of formamidine hydroiodide FAI, 0.7053 g of PbI2, 0.0059 g of MAPbBr3, and 0.0338 g of MACl in 1 mL of a mixed solvent DMF:DMSO with a volume ratio of 8:1.

[0038] (4) Neostigmine bromide (0.5, 1, 1.5, 2, 3 mg, respectively) was dissolved in 1 mL of isopropanol solution and stirred to dissolve until it was completely dissolved into a transparent colorless solution, and five bottles of passivation molecule solutions with concentrations of 0.5 mg / mL, 1 mg / mL, 1.5 mg / mL, 2 mg / mL, and 3 mg / mL were obtained. Then 25 μL of the solution was spin-coated on the above perovskite film at a spin-coating speed of 5000 rpm for 30 seconds to obtain a passivated perovskite active layer film.

[0039] (5) Preparation of hole transport layer: 101.92 mg of Spiro-OMeTAD was dissolved in 1 mL of chlorobenzene, and 45.36 μL of 4-tert-butylpyridine, 24.36 μL of lithium salt solution (520 mg of lithium bis(trifluoromethanesulfonyl)imide dissolved in 1 mL of acetonitrile) and 49.6 μL of FK209 Co(III) (300 mg of FK209 Co(III) dissolved in 1 mL of acetonitrile) were added to obtain a hole transport layer precursor solution. 25 μL of the hole transport layer precursor solution was spin-coated on the surface of the perovskite absorption layer obtained in step 4 to form a film, with a rotation speed of 4000 rpm and a spin coating time of 30 s.

[0040] (6) Preparation of metal electrodes: thermal evaporation (vacuum degree less than 10 -4 Au electrode (80 nm) was deposited under 400 Pa conditions.

[0041] Comparative Example 1

[0042] The difference between Comparative Example 1 and Example 1 is that step (4) is omitted, and the other steps are the same as Example 1.

[0043] Tables 1 and 2 show the JV curve parameters of perovskite solar cells with different concentrations of neostigmine bromide added.

[0044] Table 1

[0045]

[0046]

[0047] Table 2 JV curve parameters of perovskite solar cells with and without neostigmine bromide

[0048]

[0049] Example 2

[0050] The difference between Example 2 and Example 1 is that the conductive substrate in step (1) is changed to a flexible conductive substrate (ITO / PET), and the concentrations of neostigmine bromide passivation molecule solutions in step (4) are 0 mg / mL (Control) and 1.5 mg / mL, respectively, and the rest is the same as Example 1. Table 3 shows the JV curve parameters of flexible perovskite solar cells with and without the addition of neostigmine bromide.

[0051] Table 3 JV curve parameters of flexible perovskite solar cells with / without neostigmine bromide

[0052]

[0053] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A perovskite active layer film based on neostigmine bromide passivator, characterized in that: The perovskite active layer film comprises a perovskite active layer and a passivation layer; the passivation layer is located on the surface of the perovskite active layer; the passivation layer is composed of neostigmine bromide; the composition of the perovskite active layer is (FAPbI3) 0.95 (MAPbBr3) 0.05 .

2. A method for preparing a perovskite active layer film based on a neostigmine bromide passivator according to claim 1, characterized in that: The method comprises the following steps: dissolving neostigmine bromide in a solvent to obtain a precursor solution, spin-coating the precursor solution onto a perovskite active layer, and drying to obtain a passivated perovskite active layer film; the concentration of neostigmine bromide in the precursor solution is 0.5 mg / mL to 2 mg / mL.

3. The perovskite active layer film based on neostigmine bromide passivator according to claim 1, characterized in that: The solvent is isopropanol or ethanol.

4. The perovskite active layer film based on neostigmine bromide passivator according to claim 1, characterized in that: The spin coating parameters are: spin coating speed 3000-5000 rpm, spin coating time 30 s.

5. A perovskite solar cell, characterized in that: The structure of the perovskite solar cell device from bottom to top is: a conductive substrate, an electron transport layer, a perovskite active layer, a hole transport layer and a metal electrode, wherein the perovskite active layer is the perovskite active layer film based on the neostigmine bromide passivator as described in claim 1.

6. The perovskite solar cell according to claim 5, characterized in that: The conductive substrate is ITO glass, or FTO glass, or ITO / PEN flexible conductive substrate, or ITO / PET flexible conductive substrate.

7. The perovskite solar cell according to claim 5, characterized in that: The electron transport layer material is tin dioxide.

8. The perovskite solar cell according to claim 5, characterized in that: The hole transport layer includes lithium bis(trifluoromethanesulfonyl)imide, FK209 Co(III), 4-tert-butylpyridine, and Spiro-OMeTAD.

9. The perovskite solar cell according to claim 5, characterized in that: The metal electrode is gold or silver.

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