Perovskite active layer thin film based on neostigmine bromide passivator and preparation method and application thereof

Abstract

The present application belongs to the field of perovskite solar cell interface engineering passivation technology, a perovskite active layer film based on brominated neostigmine passivation agent and a preparation method and application thereof. The preparation method of the present application adopts a solution method operation, introduces brominated neostigmine as a passivation agent on the perovskite film, reduces the surface interface defects, and inhibits non-radiative recombination. In addition, the energy band arrangement at the interface can be improved, the charge extraction can be enhanced, and the charge accumulation can be reduced, thereby improving the stability and charge transport performance of the perovskite film, improving the quality of the perovskite active layer film, and improving the performance of the perovskite solar cell, which provides a new way for realizing high-efficiency and stable perovskite solar cells.

Description

Technical Field

[0001] This invention belongs to the field of perovskite solar cell interface engineering passivation technology, and relates to a perovskite active layer thin film based on neostigmine bromide passivating agent, its preparation method and application. Technical Background

[0002] Carbon emissions from fossil fuels have been steadily increasing over the past decade. In 2024 alone, global CO2 emissions are projected to reach 41.6 billion tons, up from 40.6 billion tons last year. The majority of these emissions come from burning energy sources such as coal, oil, and natural gas. Faced with this grim reality, reducing carbon emissions is urgently needed to avoid the dangerous impacts of climate change. Solar energy, with its abundant reserves and clean, pollution-free operation, is one of the key new energy sources being developed by countries worldwide. Perovskite solar cells (PSCs) are expected to play a significant role in the future energy sector due to their low manufacturing cost and high efficiency. However, challenges in the commercial-scale solution-based fabrication of PSCs include the use of harmful solvents, the cost of maintaining controlled atmospheric conditions, and the inherent instabilities of PSCs.

[0003] Defects in perovskite thin films mainly include lattice defects, interface defects, and surface defects. These defects severely restrict the improvement of carrier transport performance and stability of perovskite devices. Therefore, reducing perovskite defects to form high-quality film morphologies and optimizing the overall device structure and effective contact between layers are crucial for obtaining efficient and stable perovskite solar cells. Summary of the Invention

[0004] This invention aims to improve the quality of perovskite polycrystalline films by optimizing the upper surface of perovskite films and optimizing the interfacial contact between perovskite and the hole transport layer, thereby enhancing the efficiency and stability of perovskite solar cells. Currently, commonly used organic passivation molecules typically only bind to a single active site on the perovskite surface, resulting in weak binding ability. This invention provides neostigmine bromide, with multiple active sites, as a passivation agent for perovskite film passivation. This reduces voids at the grain boundaries of the perovskite film, thereby reducing the generation of surface defect states, improving the quality of the perovskite film, and increasing the charge extraction rate in the device, thus enhancing device performance. This provides a framework for the development of efficient passivation molecules for perovskite surfaces and the fabrication of high-performance perovskite photovoltaic devices. Furthermore, the neostigmine bromide passivation agent can reduce voids at the grain boundaries of the perovskite film, thereby reducing the generation of surface defect states. The specific mechanism is that the carbonyl carbon (C=O) in the neostigmine bromide passivation agent can bind with uncoordinated Pb in the perovskite. 2+ Through coordination, the quaternary ammonium group binds to the anionic sites of the perovskite via electrostatic attraction, and this dual-active site exhibits strong binding affinity to the perovskite. Neostigmine bromide treatment enhances the hydrophobicity of the perovskite surface, thereby improving the stability of the battery device under humid conditions.

[0005] Furthermore, the perovskite active layer film based on neostigmine bromide passivating agent 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 perovskite thin films based on neostigmine bromide passivating agent comprises the following steps:

[0007] The passivating molecules are first dissolved in a solvent to obtain a precursor solution of the passivating molecules. The precursor solution is then coated onto the surface of the perovskite active layer by a solution processing method such as spin coating and dried to obtain a perovskite thin film based on neostigmine bromide passivating agent.

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

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

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

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

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

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

[0014] Furthermore, a perovskite solar cell comprising the above-mentioned perovskite thin 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, wherein the perovskite active layer is the perovskite thin film based on neostigmine bromide passivating agent described above.

[0016] Furthermore, the conductive substrate is ITO (indium tin oxide) glass, FTO (fluorine-doped tin oxide) glass, 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 containing lithium bis(trifluoromethanesulfonylimide) (Li-TFSI), FK209 Co(Ⅲ) and 4-tert-butylpyridine (T-BP).

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

[0020] The advantages of this invention are:

[0021] Neostigmine bromide passivating agents have multiple active sites in their molecules, enabling them to passivate (FAPbI3). 0.95 (MAPbBr3) 0.05 This method is used to improve the surface quality of organic-inorganic hybrid perovskite solar cells by reducing porosity at grain boundaries in the perovskite film, thereby reducing the generation of surface defect states and improving the quality of the perovskite film. It also increases the charge extraction rate in the device, thus enhancing device performance. Specifically, the carbonyl carbon (C=O) in the neostigmine bromide passivating agent can react with uncoordinated Pb in the perovskite. 2+ Through coordination, the quaternary ammonium group binds to the anionic sites of the perovskite via electrostatic attraction, resulting in a strong interaction between these dual active sites and the perovskite. Introducing neostigmine bromide as a passivator onto the perovskite film suppresses nonradiative recombination, improves band alignment at the interface, enhances charge extraction, and reduces charge accumulation, thereby improving the stability and charge transport performance of the perovskite film. Furthermore, neostigmine bromide treatment enhances the hydrophobicity of the perovskite surface, thus improving the stability of the battery device under humid conditions. The optimal power conversion efficiency (PCE) of the perovskite solar cell treated with neostigmine bromide in this invention is 24.39%, the open-circuit voltage is 1.17V, and the short-circuit current is 25.78mA / cm². 2 The fill 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. Attached Figure Description

[0022] Figure 1 This illustrates the device structure of the perovskite solar cell in Embodiment 1 of the present invention;

[0023] Figure 2 This illustrates the device structure of the flexible perovskite solar cell in Embodiment 2 of the present invention;

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

[0025] Figure 4 The JV curves of perovskite cells passivated with neostigmine bromide under different concentration conditions 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) / no neostigmine bromide passivation in Example 1 is shown.

[0027] Figure 6 The JV curves represent the perovskite solar cells passivated with (1.5 mg / mL) / no neostigmine bromide in Example 1 of the present invention.

[0028] Figure 7 The JV curves of the flexible perovskite solar cell with and without neostigmine bromide passivation in Example 2 of the present invention are shown.

[0029] Figure 8 The thermal stability performance of perovskite solar cells passivated with (1.5 mg / mL) and no neostigmine bromide is compared in Example 1 of the present invention.

[0030] Figure 9 This indicates that the perovskite solar cell with (1.5 mg / mL) / non-neostigmine passivation in Example 1 of the present invention is exposed to light (100 mW / cm²). 2 Stability test comparison of AM1.5G;

[0031] Figure 10 This indicates a comparison of the mechanical stability tests of perovskite solar cells passivated with neostigmine bromide (1.5 mg / mL) and without neostigmine bromide in Example 1 of the present invention. Detailed Implementation

[0032] The present invention will be described in detail below with reference to the embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0033] Example 1

[0034] The fabrication method of perovskite solar cells containing a neostigmine bromide passivation layer includes the following steps:

[0035] (1) Cleaning of the conductive substrate: The conductive substrate (ITO (FTO) / glass) was ultrasonically cleaned for 20 minutes in sequence with conductive glass cleaner, deionized water, acetone, isopropanol and alcohol. After cleaning, it was placed in an oven to dry for later use; the conductive substrate was ITO glass.

[0036] (2) Electron transport layer preparation: A 15 wt% tin oxide nanocrystal solution was dissolved in deionized water and diluted at a ratio of 1:3. After sonication in cold water for 15 min, the solution was filtered through a 0.45 μm polyethersulfone filter. 100 μL of the solution was spin-coated onto a clean ITO glass substrate (the ITO glass was ozone-treated for 20 min before spin-coating). The spin-coating speed was 3000 rpm, the acceleration was 500 rpm / s, and the spin-coating time was 45 s. The substrate was 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 min, a perovskite precursor solution was spin-coated onto the surface of the electron transport layer. The first stage was 1000 rpm, 2000 rpm / s acceleration, and 10 s time. The second stage was 5000 rpm, 2000 rpm / s acceleration, and 30 s spin-coating time. 110 μL of chlorobenzene was added dropwise at 10 s in the second stage. After spin-coating, the layer was placed on a heating stage and heated at 100℃ for 60 min. The perovskite precursor solution was prepared by dissolving 0.2408 g of formamidinium 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, and 3 mg respectively) was dissolved in 1 mL of isopropanol solution and stirred until completely dissolved into a transparent and colorless solution, yielding five passivation molecular solutions with concentrations of 0.5 mg / mL, 1 mg / mL, 1.5 mg / mL, 2 mg / mL, and 3 mg / mL respectively. Then, 25 μL of the solution was spin-coated onto the above perovskite film at a spin speed of 5000 rpm for 30 s to obtain a passivated perovskite active layer film.

[0039] (5) Hole transport layer preparation: 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(trifluoromethanesulfonylimide) 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 the hole transport layer precursor solution. 25 μL of the hole transport layer precursor solution was spin-coated onto the surface of the perovskite absorber layer obtained in step 4 and a film was formed at a spin speed of 4000 rpm for 30 s.

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

[0041] Comparative Example 1

[0042] The difference between Comparative Example 1 and Example 1 is that step (4) is omitted, while the rest is 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.

[0044] Table 1

[0045]

[0046]

[0047] Table 2 JV curve parameters of perovskite solar cells with / 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 the neostigmine bromide passivation molecular solution taken in step (4) are 0 mg / mL (Control) and 1.5 mg / mL, respectively. The rest is the same as in Example 1. Table 3 shows the JV curve parameters of the 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 description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A perovskite active layer film based on neostigmine bromide passivating agent, characterized in that, The perovskite active layer film includes 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 perovskite active layer is composed of (FAPbI3). 0.95 (MAPbBr3) 0.05 .

2. A method for preparing a perovskite active layer thin film based on neostigmine bromide passivating agent according to claim 1, characterized in that, The process includes 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 it 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 method for preparing a perovskite active layer film based on neostigmine bromide passivating agent according to claim 2, characterized in that, The solvent is isopropanol or ethanol.

4. The method for preparing a perovskite active layer film based on neostigmine bromide passivating agent according to claim 2, 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 perovskite solar cell device structure, from bottom to top, consists of: 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 thin film based on neostigmine bromide passivating agent 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 comprises lithium bis(trifluoromethanesulfonylimide), FK209 Co(Ⅲ), and 4-tert-butylpyridine or Spiro-OMeTAD.

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

Images