Additives containing poly[(phenyl isocyanate)-co-formaldehyde] derivatives and uses thereof

Abstract

This invention provides an additive containing a poly[(phenyl isocyanate)-copolyoxymethylene] derivative and its uses. The additive of this invention is a derivative of formula (I) obtained by modifying poly[(phenyl isocyanate)-copolyoxymethylene]. By adding this additive to the perovskite precursor solution, during the crystallization process, the hydrogen bonding coordination ability of the urea group (-NH-C(=O)-NH-) interacts with the π-π stacking of the benzene ring, effectively passivating defect sites at perovskite grain boundaries and on the thin film surface, regulating grain nucleation and growth kinetics, thereby simultaneously improving the power conversion efficiency (PCE) and long-term thermal stability of perovskite solar cells.

Description

Technical Field

[0001] This invention relates to an additive material and its application. Specifically, it uses a derivative obtained by modifying poly[(phenyl isocyanate)-copolyoxymethylene] as an additive material. This additive material can be added to the perovskite precursor solution to passivate defect sites in the perovskite active layer and optimize the crystallization quality of the perovskite thin film during the crystallization process, thereby improving the energy conversion efficiency and long-term stability of perovskite optoelectronic devices. This invention belongs to the field of organic optoelectronic materials and perovskite solar cell technology. Background Technology

[0002] With the evolution of the times, the consumption of energy resources such as coal, oil, natural gas, and nuclear energy has been increasing, leading to a relative emergence of the energy crisis. This has spurred the development of solar power generation. Solar power generation is a renewable and environmentally friendly method that can reduce environmental pollution. First-generation solar cells primarily used silicon-based solar cells, which had high photoelectric conversion efficiency. Second-generation solar cells were thin-film cadmium telluride (CdTe) solar cells, but the toxicity of their raw materials and the manufacturing process caused significant environmental pollution. Therefore, third-generation organic solar cells emerged, including dye-sensitized solar cells (DSSC), perovskite solar cells (PSC), and organic photovoltaic (OPV). Compared to inorganic materials that require vacuum coating processes, perovskite and organic solar cells can be manufactured using dip coating, spin coating, slot coating, screen printing, inkjet printing, etc., making it easier to achieve low-cost and large-scale production.

[0003] Given the various types of defects present in the perovskite active layer during crystallization, these defects are the main factors limiting the performance and stability of perovskite solar cells. In terms of the nature of these defects, during perovskite film formation, due to uneven grain nucleation rates, difficulty in precisely controlling solvent evaporation rates, and the complexity of the precursor solution composition, numerous point defects are easily generated at grain boundaries and on the film surface. These defects include halide vacancy, lead vacancy, and interstitial ions. Among these, halide vacancy is the most prevalent type of defect. It can act as a non-radiative recombination center, trapping photo-generated carriers, preventing effective charge transfer to the functional layers, and consequently causing open-circuit voltage (Voc) loss and a decrease in fill factor (FF), thus reducing the overall power conversion efficiency (PCE). Furthermore, halogen vacancies are also a major pathway for ion migration. Under illumination or applied voltage, halide ions (such as I⁻) can migrate directionally along vacancy defect channels, causing local imbalances in the perovskite composition, thin film phase segregation, and current-voltage hysteresis (JV hysteresis) in the device, thus significantly shortening the device's lifespan. This is especially true in the fabrication of large-area perovskite modules, where the requirements for coating uniformity are more stringent, and crystallization defects are more prominent, becoming a significant bottleneck hindering the commercial application of perovskite technology. Therefore, academia and industry frequently use additives to regulate the perovskite crystallization process and passivate defect sites, aiming to simultaneously improve efficiency and long-term stability. Summary of the Invention

[0004] Given that point defects such as halogen vacancies, lead vacancies, and interstitial ions are easily generated during the crystallization process of perovskite active layers, these defect sites act as non-radiative recombination centers, causing obstacles to photogenerated carrier capture and charge transfer, and inducing ion migration and thin film phase separation, thereby leading to a decrease in energy conversion efficiency and a shortened device lifespan. This problem is particularly pronounced when fabricating large-area perovskite modules, where crystallization uniformity is difficult to control. To address these technical issues, this invention provides an additive containing a poly[(phenyl isocyanate)-copolyoxymethylene] derivative and its uses. This additive uses a derivative obtained by modifying poly[(phenyl isocyanate)-copolyoxymethylene] as its material. By adding this additive to the perovskite precursor solution, during the crystallization process, the hydrogen bonding coordination ability of the urea group (-NH-C(=O)-NH-) and the π-π stacking interaction of the benzene ring effectively passivate defect sites at perovskite grain boundaries and on the thin film surface, regulate grain nucleation and growth kinetics, and thus simultaneously improve the energy conversion efficiency (PCE) and long-term thermal stability of perovskite solar cells.

[0005] To achieve the aforementioned objective, the present invention provides an additive containing a poly[(phenyl isocyanate)-copolyoxymethylene] derivative, which is shown in formula (I) below: Among them, R 0 The additive is selected from unsubstituted or at least F-substituted C1 to C8 straight-chain, branched, or cyclic alkyl groups, or benzene alkyl groups on the benzene ring, each of which is independently selected from H, F, or CF3 and the methylene chain length n is 1 or 2. The additive containing poly[(phenyl isocyanate)-copolyoxymethylene] derivatives provided by this invention can be added to a perovskite precursor solution, which is used to prepare a perovskite active layer for a perovskite optoelectronic device.

[0006] According to the present invention, in the derivative shown in formula (I) above, R 0 As shown in equation (II): Among them, R 1 To R 5 Each is independently selected from H, F, or CF3; and n is 1 or 2. By introducing isoelectronogenic substituents such as F or CF3 onto the benzene ring of the phenylalkyl group, the interaction between the additive and lead ions (Pb) in the perovskite lattice can be enhanced. 2+ The Lewis acid-base coordination of the additives further enhances the defect passivation effect and can adjust the energy level matching of the additives, which is beneficial to carrier transport.

[0007] According to the present invention, in the derivative shown in formula (I) above, R 0 It is an unsubstituted C1 to C8 straight-chain, branched, or cyclic alkyl group. Alkyl type R 0Imparting appropriate flexible segments to the additives can improve their compatibility with the perovskite precursor solution and help regulate the crystallization rate of the perovskite film during the film formation process, which is beneficial for forming a dense film with low defect density.

[0008] According to the present invention, in the derivative shown in formula (I) above, R 0 It is a C1 to C8 straight-chain, branched, or cyclic alkyl group substituted with at least one F. The strong electronegativity of fluorinated alkyl groups can enhance the passivation ability of additives to perovskite defect sites.

[0009] According to the present invention, in the derivative shown in formula (I) above, R 0 Selected from: Methyl (-CH3), n-Butyl(-n-C4H9, ), octyl (-n-C8H) 17 , ), 4-Fluorobenzyl(-CH2C6H4F, ), 4-(trifluoromethyl)benzyl(-CH2C6H4CF3, ), Phenylacetyl (-CH2CH2C6H5, ),or 4-Fluorophenylethyl (-CH2CH2C6H4F, ). The aforementioned specific R 0 The structures have all been synthesized and verified through the embodiments in this specification, and have been confirmed in application examples to have a substantial effect on improving the performance of perovskite solar cells, which are the preferred embodiments of the present invention.

[0010] According to the present invention, the preparation steps of the additive containing poly[(phenyl isocyanate)-copolyoxymethylene] derivatives include: dissolving commercially available poly[(phenyl isocyanate)-copolyoxymethylene] (Merck, CAS# 9016-87-9) in anhydrous dimethylformamide (DMF), and sequentially adding an amine reagent selected from the following under nitrogen (N2) protection: (i) R 0 -NH2 in the free amine form, where R 0 It is selected from unsubstituted C1 to C8 straight-chain, branched, or cyclic alkyl groups, or substituents R on the benzene ring. 1 To R 5 Each of the following is independently selected from H, F or CF3 and has a methylene chain length n of 1 or 2 as a benzyl group; or (ii) the aforementioned R 0An acid addition salt of -NH2 (optionally including hydrochloride forms, such as methylamine hydrochloride (CH3NH3Cl)) and a suitable organic base (optionally including triethylamine (Et3N)) are placed in an oil bath preheated to 60°C and heated with stirring for 18 hours. After the reaction is complete, the mixture is cooled to room temperature, filtered through a white porcelain funnel under vacuum, and the solid is washed with methanol (CH3OH) and filtered again, repeated at least three times. The product is dried to give a white solid product.

[0011] In one embodiment, in the aforementioned method using anhydrous dimethylformamide (DMF) as a solvent, the amine reagent is introduced in the form of an acid addition salt (e.g., hydrochloride) combined with an organic base (e.g., triethylamine, Et3N). The amount of the amine reagent (acid addition salt) relative to the isocyanate functional groups (-NCO) contained in the poly[(phenyl isocyanate)-copolyoxymethylene] can be about 1.5 to 5.0 equivalents (mol / mol), and the molar ratio of the amine reagent (acid addition salt) to the organic base can be about 0.8:1 to 2.0:1.

[0012] In another embodiment, the amount of amine reagent (acid addition salt) relative to the isocyanate functional groups (-NCO) contained in poly[(phenyl isocyanate)-copolyoxymethylene] can be about 1.5 equivalents (mol / mol), 1.75 mol / mol, 2.0 mol / mol, 2.25 mol / mol, 2.5 mol / mol, 2.75 mol / mol, 3.0 mol / mol, 3.25 mol / mol, 3.5 mol / mol, 3.75 mol / mol, 4.0 mol / mol, 4.25 mol / mol, 4.5 mol / mol, 4.75 mol / mol, or 5.0 mol / mol; the aforementioned equivalents can be within the range formed by any two of the above values, but are not limited to them.

[0013] In another embodiment, the molar ratio of the amine reagent (acid addition salt) to the organic base may be approximately 0.8:1, 0.9:1, 1.0:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, or 2.0:1; the aforementioned molar ratio may fall within the range formed by any two of the above values, but is not limited to them.

[0014] According to the present invention, the preparation steps of the additive containing poly[(phenyl isocyanate)-copolyoxymethylene] derivatives include: dissolving commercially available poly[(phenyl isocyanate)-copolyoxymethylene] (Merck, CAS# 9016-87-9) in chlorobenzene (CB), and adding an amine compound selected from the following under nitrogen (N2) protection (R... 0-NH2): (i) unsubstituted C1 to C8 straight-chain, branched, or cyclic alkylamines; or (ii) substituent R on the benzene ring. 1 To R 5 Each phenylalkylamine (i.e., R represented by formula (II)) is independently selected from H, F or CF3 and has a methylene chain length n of 1 or 2. 0 -NH2); Stirred at room temperature for 3 hours, a white solid precipitated, filtered through a white porcelain funnel under vacuum, and washed with methanol before filtration, repeated at least three times. After drying, a white solid product was obtained.

[0015] In one embodiment, in the aforementioned preparation method using chlorobenzene (CB) as a solvent, the amine compound (R) 0 The amount of -NH2) can be about 1.5 to 5.0 equivalents (mol / mol) relative to the isocyanate functional groups (-NCO) contained in poly[(phenyl isocyanate)-copolyacetal], that is, the molar ratio of amine compound to isocyanate functional group can be about 1.5:1 to 5.0:1.

[0016] In another embodiment, amine compounds (R) 0 The amount of -NH2) relative to the isocyanate functional group (-NCO) in poly[(phenyl isocyanate)-copolyacetal] can be about 1.5 equivalents (mol / mol), 1.75 mol / mol, 2.0 mol / mol, 2.25 mol / mol, 2.5 mol / mol, 2.75 mol / mol, 3.0 mol / mol, 3.25 mol / mol, 3.5 mol / mol, 3.75 mol / mol, 4.0 mol / mol, 4.25 mol / mol, 4.5 mol / mol, 4.75 mol / mol, or 5.0 mol / mol; the aforementioned equivalents can be within the range formed by any two of the above values, but are not limited to them.

[0017] In another embodiment, the molar ratio of the amine compound to the isocyanate functional group may be about 1.5:1, 1.75:1, 2:1, 2.25:1, 2.5:1, 2.75:1, 3:1, 3.25:1, 3.5:1, 3.75:1, 4:1, 4.25:1, 4.5:1, 4.75:1, or 5:1; the aforementioned molar ratio may be within the range formed by any two of the above values, but is not limited to this.

[0018] To achieve the aforementioned objectives, the present invention further provides the use of the aforementioned additive in the preparation of a perovskite active layer of a perovskite optoelectronic device. By introducing the additive shown in formula (I) into the preparation process of the perovskite active layer, the microstructure of the perovskite thin film can be effectively optimized, the defect state density reduced, thereby improving the overall photoelectric conversion efficiency of the optoelectronic device.

[0019] According to the present invention, in the aforementioned applications, the additive is formed by modifying poly[(phenyl isocyanate)-copolyoxymethylene], and then crystallizing it in a perovskite precursor solution to form the perovskite active layer. Introducing the additive through precursor solution blending ensures uniform dispersion of the additive in the perovskite precursor solution, and allows it to continuously participate in regulating grain growth during solvent removal and annealing crystallization processes. This method achieves more comprehensive passivation of perovskite bulk defects than surface treatment methods.

[0020] According to the present invention, in the aforementioned uses, the concentration of the additive in each milliliter (mL) of perovskite precursor solution is from 0.1 mg to 5 mg. Specifically, the concentration of the additive in each milliliter of perovskite precursor solution can be 0.1 mg, 0.2 mg, 0.3 mg, 0.4 mg, 0.5 mg, 0.6 mg, 0.7 mg, 0.8 mg, 0.9 mg, 1.0 mg, 1.1 mg, 1.2 mg, 1.3 mg, 1.4 mg, 1.5 mg, 1.6 mg, 1.7 mg, 1.8 mg, 1.9 mg, 2.0 mg, 2.1 mg, 2.2 mg, 2.3 mg, 2.4 mg, 2.5 mg, 2.6 mg, 2.7 mg, etc. The concentrations of the additive in the perovskite precursor solution may be 2.8 mg, 2.9 mg, 3.0 mg, 3.1 mg, 3.2 mg, 3.3 mg, 3.4 mg, 3.5 mg, 3.6 mg, 3.7 mg, 3.8 mg, 3.9 mg, 4.0 mg, 4.1 mg, 4.2 mg, 4.3 mg, 4.4 mg, 4.5 mg, 4.6 mg, 4.7 mg, 4.8 mg, 4.9 mg, or 5.0 mg; the concentration of the additive in each milliliter of perovskite precursor solution may fall within the range of any two of the above values, but is not limited to them.

[0021] According to the present invention, in the aforementioned applications, the perovskite active layer comprises HC(NH2)2I, CsI, PbI2, and PbBr2. The aforementioned mixed halide perovskite composition exhibits excellent light absorption characteristics and good thermal stability, and is well-compatible with the passivation mechanism of the additives of the present invention.

[0022] According to the present invention, the perovskite precursor solution is prepared by mixing HC(NH2)2I, CsI, PbI2, and PbBr2 in a molar ratio of HC(NH2)2I:CsI of 0.70 to 0.95:0.05 to 0.30, and a molar ratio of PbI2:PbBr2 of 0.70 to 0.95:0.05 to 0.30, wherein Pb reacts with (HC(NH2)2I)CsI to form PbBr2. + +Cs +The total molar ratio of the raw materials was mixed in the range of 0.9 to 1.1 and dissolved in a mixed solvent of dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), wherein the volume ratio of DMF to DMSO was 7:3 to 9.5:0.5 (v / v). The aforementioned range of raw material ratios was designed based on considerations of the phase stability of the mixed cation and mixed halide perovskite system, and was adjusted by... + / Cs + Proportion and I - / Br - The ratio can optimize the thermal stability and bandgap matching of the perovskite crystal phase; while the regulation of the DMF / DMSO solvent ratio helps to precisely control the crystallization kinetics and obtain high-quality perovskite films with low defect density.

[0023] In one embodiment, in the preparation of the perovskite precursor solution, the molar ratio of HC(NH2)2I to CsI is 0.70 to 0.95: 0.05 to 0.30, wherein the molar ratio of HC(NH2)2I can be selected from 0.70, 0.75, 0.80, 0.83, 0.85, 0.90 or 0.95, and the molar ratio of CsI can be selected from 0.05, 0.10, 0.15, 0.17, 0.20, 0.25 or 0.30, and the sum of the molar ratios of HC(NH2)2I and CsI is 1.00.

[0024] In one embodiment, in the preparation of the perovskite precursor solution, the molar ratio of PbI2 to PbBr2 is 0.70 to 0.95: 0.05 to 0.30, wherein the molar ratio of PbI2 can be selected from 0.70, 0.75, 0.80, 0.85, 0.90 or 0.95, and the molar ratio of PbBr2 can be selected from 0.05, 0.10, 0.15, 0.20, 0.25 or 0.30, and the sum of the molar ratios of PbI2 and PbBr2 is 1.00.

[0025] In one embodiment, in the preparation of the perovskite precursor solution, the volume ratio (v / v) of dimethylformamide (DMF) to dimethyl sulfoxide (DMSO) is 7:3 to 9.5:0.5, wherein the volume ratio of DMF can be selected from 7.0, 7.5, 8.0, 8.5, 9.0, and 9.5, and the volume ratio of DMSO can be selected from 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0, and the total volume ratio of DMF to DMSO is 10.0.

[0026] According to the present invention, in the aforementioned applications, the perovskite optoelectronic element is a perovskite solar cell. The perovskite solar cell comprises a substrate, a first electrode deposited on the substrate, a hole transport layer deposited on the first electrode, a perovskite active layer deposited on the hole transport layer, an electron transport layer deposited on the perovskite active layer, an electron modification layer deposited on the electron transport layer, and a second electrode deposited on the electron modification layer. The aforementioned element structure adopts a positive (nip) architecture, and the stacking order of the functional layers facilitates the directional transport of photogenerated carriers. The perovskite active layer containing the additives of the present invention, as the core functional layer for light absorption and carrier generation, can simultaneously improve the open-circuit voltage (Voc), short-circuit current (Jsc), and fill factor (FF) through defect passivation effects, thereby significantly improving the overall energy conversion efficiency.

[0027] The beneficial effects of this invention are as follows: This invention provides an additive material containing the compound shown in formula (I) as a perovskite solar cell. This additive material is a modified derivative with a polymer backbone, which has better film-forming properties, mechanical properties, and thermal stability compared to known small molecule additives. By adding the aforementioned additive to the perovskite precursor solution, defect sites in the perovskite active layer can be effectively passivated and non-radiative recombination losses can be reduced during the crystallization process, thereby significantly improving the energy conversion efficiency of the perovskite solar cell. At the same time, the excellent thermal stability imparted by the polymer backbone also enables the device to maintain a high efficiency retention rate during long-term use or under high-temperature environments, achieving the dual technical effects of improved efficiency and stability.

[0028] The preferred embodiments of the present invention, along with accompanying drawings, are described in detail below to explain the techniques, methods, and other beneficial effects used to achieve the above objectives. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the element structure of the perovskite solar cell of the present invention.

[0030] Figure 2 The voltage-current density curves of the perovskite solar cells of Comparative Example 1 (C1) and Application Examples 2A, 4A, and 7A (E2A, E4A, E7A) of the present invention are shown.

[0031] Figure 3 The Fourier transform infrared (FTIR) spectra of the additives containing poly[(phenyl isocyanate)-copolyacetal] derivatives in various embodiments of the present invention are shown.

[0032] Figure 4 This is a photoluminescence (PL) mapping diagram of the perovskite thin films (E2A, E4A, and E7A) containing additives of the present invention and the control film (C1) without additives.

[0033] Explanation of markings in the diagram: 10: Perovskite solar cells 11: Substrate 12: First electrode 13: Hole transport layer 14: Perovskite active layer 15: Electron transport layer 16: Electronic modification layer 17: Second electrode. Detailed Implementation

[0034] To facilitate understanding of the present invention, the following description, in conjunction with embodiments, comparative examples, and application examples, illustrates the preparation of the additive materials of the present invention, the structure of perovskite solar cells containing the aforementioned additive materials, and their preparation.

[0035] Some embodiments of the features and advantages of the present invention will be described in detail in the following description. It should be understood that the present invention can be varied in different ways without departing from the scope of the invention, and the description herein is for illustrative purposes only and not for limiting the invention.

[0036] Preparation of Additive Materials The following describes the preparation methods, reaction pathways, and specific reaction formulas of Examples 1 to 7 of the present invention.

[0037] The reaction pathway A of Example 1 (E1) is shown below.

[0038] [Reaction Pathway A]

[0039] Example 1 (E1): The reaction pathway in this embodiment is shown in Reaction Formula 1 below.

[0040] [Reaction Formula 1]: [Compound 1, PPI-MA] In Example 1, commercially available poly[(phenyl isocyanate)-copolyoxymethylene] (Merck, CAS# 9016-87-9, 1.00 g, 2.5 mmol) was dissolved in anhydrous dimethylformamide (DMF, 30 mL). Under nitrogen (N2) protection, methylamine hydrochloride (CH3NH3Cl, 0.50 g, 7.5 mmol) and triethylamine (Et3N, 0.76 g, 7.5 mmol) were added sequentially. The mixture was placed in an oil bath preheated to 60°C and stirred for 18 hours. After the reaction was complete, the mixture was cooled to room temperature, filtered through a white porcelain funnel (Buchner funnel), and washed with methanol (CH3OH) before filtration. This process was repeated at least three times. After drying, 0.76 g of a white solid product, compound 1 (PPI-MA), was obtained in 67.6% yield.

[0041] The reaction pathways B of Examples 2 to 7 (E2 to E7) are shown below.

[0042] [Reaction Pathway B]: Example 2 (E2): The reaction pathway in this embodiment is shown in reaction formula 2 below.

[0043] [Reaction 2]: [Compound 2, PPI-BA] In Example 2, poly[(phenyl isocyanate)-copolyoxymethylene] (1.0 g, 2.5 mmol) was dissolved in chlorobenzene (CB, 30 mL), and n-butylamine was added under nitrogen protection. 0.55 g (7.5 mmol) was stirred at room temperature (rt) for 3 hours, precipitating a white solid. The solid was filtered through a white porcelain funnel under vacuum, and washed with methanol before filtration. This process was repeated at least three times. After drying, 1.21 g of a white solid product, in 83.9% yield, of compound 2 (PPI-BA) was obtained.

[0044] Example 3 (E3): The reaction pathway in this embodiment is shown in reaction formula 3 below.

[0045] [Reaction 3]: [Compound 3, PPI-OA] In Example 3, poly[(phenyl isocyanate)-copolyoxymethylene] (1.0 g, 2.5 mmol) was dissolved in chlorobenzene (CB, 30 mL), and n-octylamine was added under nitrogen protection. 0.97 g (7.5 mmol) was stirred at room temperature (rt) for 3 hours, precipitating a white solid. The solid was filtered through a white porcelain funnel under vacuum, and washed with methanol before filtration. This process was repeated at least three times. After drying, 1.36 g of a white solid product, in 64.7% yield, of compound 3 (PPI-OA) was obtained.

[0046] Example 4 (E4): The reaction pathway in this embodiment is shown in reaction formula 4 below.

[0047] [Reaction 4]: [Compound 4, PPI-FBZA] In Example 4, poly[(phenyl isocyanate)-copolyoxymethylene] (1.00 g, 2.5 mmol) was dissolved in chlorobenzene (30 mL), and 4-fluorobenzylamine was added under nitrogen protection. 0.94 g (7.5 mmol) was stirred at room temperature for 3 hours, precipitating a white solid. The solid was filtered through a white porcelain funnel under vacuum, washed with methanol, and filtered again, repeated at least three times. After drying, 1.2 g of white solid product, compound 4 (PPI-FBZA), was obtained in 63.1% yield.

[0048] Example 5 (E5): The reaction pathway in this embodiment is shown in reaction formula 5 below.

[0049] [Reaction 5]: [Compound 5, PPI-CF3BZA] In Example 5, poly[(phenyl isocyanate)-copolyoxymethylene] (1.00 g, 2.5 mmol) was dissolved in chlorobenzene (30 mL), and 4-(trifluoromethyl)benzylamine was added under nitrogen protection. 1.90 g (7.5 mmol) was stirred at room temperature for 3 hours, and a white solid precipitated. The solid was filtered through a white porcelain funnel under vacuum, and washed with methanol before filtration. This process was repeated at least three times. After drying, 1.4 g of a white solid product was obtained, yielding compound 5 (PPI-CF3BZA) in 65.3% yield.

[0050] Example 6 (E6): The reaction pathway in this embodiment is shown in reaction formula 6 below.

[0051] [Reaction 6]: [Compound 6, PPI-PEA] In Example 6, poly[(phenyl isocyanate)-copolyoxymethylene] (1.0 g, 2.5 mmol) was dissolved in chlorobenzene (30 mL), and phenylethylamine was added under nitrogen protection. 0.91 g (7.5 mmol) was stirred at room temperature for 3 hours, precipitating a white solid. The solid was filtered through a white porcelain funnel under vacuum, and washed with methanol before filtration. This process was repeated at least three times. After drying, 1.39 g of a white solid product, in 77.3% yield, was obtained, representing compound 6 (PPI-PEA).

[0052] Example 7 (E7): The reaction pathway in this embodiment is shown in reaction formula 7 below.

[0053] [Reaction 7]: [Compound 7, PPI-FPEA] In Example 7, poly[(phenyl isocyanate)-copolyoxymethylene] (1.00 g, 2.5 mmol) was dissolved in chlorobenzene (30 mL), and 2-(4-fluorophenyl)ethylamine was added under nitrogen protection. 2.00 g (7.5 mmol) was stirred at room temperature for 3 hours, precipitating a white solid. The solid was filtered through a white porcelain funnel under vacuum, and washed with methanol before filtration. This process was repeated at least three times. After drying, 0.86 g of a white solid product, in 52.3% yield, was obtained, representing compound 7 (PPI-FPEA).

[0054] The Structure of Perovskite Solar Cells Figure 1 This is a cross-sectional view of the structure of the perovskite solar cell 10 used in this invention. The perovskite solar cell 10 includes a substrate 11, a first electrode 12 stacked on the substrate 11, a hole transport layer 13 stacked on the first electrode 12, a perovskite active layer 14 stacked on the hole transport layer 13, an electron transport layer 15 stacked on the perovskite active layer 14, an electron modification layer 16 stacked on the electron transport layer 15, and a second electrode 17 stacked on the electron modification layer 16.

[0055] Fabrication of Perovskite Solar Cells This invention involves adding the poly[(phenyl isocyanate)-copolyoxymethylene] derivative obtained in Examples 2 (E2), 4 (E4), and 7 (E7) as an additive to the perovskite active layer 14 of the perovskite solar cell 10, to form application examples of perovskite optoelectronic devices of Examples 2, 4, and 7 (corresponding codes are E2A, E4A, and E7A, respectively). A set of perovskite optoelectronic devices with no additives added to the perovskite active layer 14 is also provided as Comparative Example 1 (C1).

[0056] The perovskite solar cell 10 of the present invention undergoes pre-treatment of a perovskite precursor solution before fabrication. The specific steps include: mixing the perovskite raw material components HC(NH₂)₂I, CsI, PbI₂, and PbBr₂ in a molar ratio of 0.83:0.17:0.85:0.15 with the solvent dimethylformamide / dimethyl sulfoxide (9:1 v / v) to form a perovskite precursor solution with a solid content of approximately 49 wt%. Depending on the application example (E2A, E4A, E7A), approximately 0.1 mg to 5 mg of additive material is added to each milliliter of the perovskite precursor solution.

[0057] The specific fabrication steps of the perovskite solar cell 10 of the present invention include: (1) The patterned ITO (indium tin oxide) glass substrate (with a resistance of 12 Ω / sq) is sequentially cleaned in an ultrasonic oscillation bath using a cleaning agent, deionized water, acetone, and isopropyl alcohol (IPA) for 10 minutes each. After ultrasonic cleaning, the ITO glass substrate undergoes surface treatment in a UV-ozone cleaner for 30 minutes. The glass substrate is the substrate 11 of the perovskite solar cell 10, and the ITO layer is the first electrode 12.

[0058] (2) Poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) is mixed with toluene to form a solution with a solid content of approximately 1.5 wt%. This solution is coated onto the first electrode 12 and baked at approximately 100°C to 120°C for 10 to 30 minutes to form a hole transport layer 13 with a thickness of approximately 20 nm.

[0059] (3) The perovskite precursor liquid containing the additive of the present invention containing poly[(phenyl isocyanate)-copolyacetal] derivative prepared above is coated on the hole transport layer 13, the solvent is removed by vacuum decompression, and the perovskite active layer 14 with a thickness of about 400 nm is formed after baking at about 100°C to 110°C for 30 to 60 minutes.

[0060] (4) [6,6]-phenyl-C 61 Methyl butyrate ([6,6]-Phenyl-C) 61 -butyric acid methylester (PCBM

[60] ) was mixed with solvent chlorobenzene to form a solution with a solid content of about 2.5 wt%. The solution was coated on the perovskite active layer 14 and baked at about 80°C to 100°C for about 10 minutes to form an electron transport layer 15 with a thickness of about 50 nm.

[0061] (5) Polyetherimide (PEI) is mixed with dibutanol (2-Butanol) to form a solution with a solid content of about 0.05 wt%. The solution is coated onto the electron transport layer 15 and baked at about 90°C to 100°C for about 6 minutes to form an electron modification layer 16 with a thickness of about 2 nm.

[0062] (6) The sample obtained above is sent into a vacuum chamber and then subjected to a pressure of 1.0 × 10⁻⁶. ‒6 Silver metal is deposited under TOR (torrential temperature) to form a second electrode 17 with a thickness of about 100 nm on the electron-modified layer 16, thus obtaining the perovskite solar cell 10.

[0063] Fourier Transform Infrared (FTIR) Spectroscopic Structure Confirmation of Additive Materials To confirm the chemical structure of the additives containing poly[(phenyl isocyanate)-copolyacetal] derivatives synthesized in each embodiment (E1 to E7) of the present invention, Fourier-Transform Infrared Spectroscopy (FTIR) analysis was performed on the products of each synthesis example. The results are as follows: Figure 3 As shown. By Figure 3 It can be observed that the characteristic absorption peak of the isocyanate functional group (-NCO) of the starting material poly[(phenyl isocyanate)-copolyacetal] significantly disappeared in the FTIR spectra of the products of each example, and the corresponding characteristic absorption peak of the urea group (-NH-C(=O)-NH-) appeared, confirming that the -NCO functional group of the polymer backbone has reacted with the corresponding amine reagent (R 0-NH2) reacts completely and forms urea bonds, verifying that the chemical structure of the additive materials in each embodiment of the present invention conforms to the expected target structure shown in formula (I), and confirming the integrity of the synthesis reaction.

[0064] Characterization of Defect Passivation Mechanism (Photoluminescence Analysis) To directly verify the effect of the poly[(phenyl isocyanate)-copolyoxymethylene] derivative additive of the present invention on the passivation of defects in perovskite films, photoluminescence (PL) mapping analysis was performed on the control group (C1) without additives and the perovskite films with additives from Examples 2 (PPI-BA), 4 (PPI-FBZA), and 7 (PPI-FPEA) of the present invention. The results are as follows: Figure 4 As shown. By Figure 4 The PL mapping diagrams show that the PL emission color of the control group C1 is bluer and unevenly distributed, indicating a high density of defect sites in the perovskite film. This makes it prone to nonradiative recombination of photogenerated carriers, resulting in weak PL intensity and insufficient spatial uniformity. In contrast, the perovskite films with added samples from Examples 2 (E2), 4 (E4), and 7 (E7) of this invention exhibit a significantly yellower, more uniform, and brighter PL emission color, indicating a reduced defect density and effective suppression of nonradiative recombination. This results in enhanced PL intensity and a more uniform spatial distribution. This PL mapping analysis directly characterizes the passivation effect of the additives of this invention on perovskite film defects: the pulsar group (-NH-C(=O)-NH-) of the additive molecules effectively passivates halogen vacancies and other defect sites through hydrogen bonding, reducing the density of nonradiative recombination centers and thus improving the radiative recombination efficiency of photogenerated carriers. This passivation mechanism is the basis for the improved energy conversion efficiency of the driving element driven by the additives of this invention.

[0065] Analysis of Power Conversion Efficiency (PCE) of Perovskite Solar Cells Figure 2 The figures shown are voltage-current density (JV) characteristic curves of the preferred embodiments of the present invention (E2, E4, and E7) and the control element (C1) without additives, measured under standard AM 1.5G simulated sunlight (illuminance 100 mW / cm2) irradiation conditions. Figure 2 It can be clearly observed that the JV curves of the three groups of elements (E2A, E4A, E7A) containing the additives of the present invention show varying degrees of improvement in open-circuit voltage (Voc) and current density (Jsc) compared with the control element C1, reflecting that the additives of the present invention effectively reduce the defect state density of the perovskite active layer and improve the carrier transport characteristics.

[0066] To evaluate the effect of the additive materials of the present invention on the photoelectric efficiency of perovskite solar cells, a control element (C1) without any additives, an element prepared according to Example 2 (PPI-BA) (E2A), an element prepared according to Example 4 (PPI-FBZA) (E4A), and an element prepared according to Example 7 (PPI-FPEA) (E7A) were prepared according to the aforementioned preparation method. The measurement area of ​​the perovskite solar cell was defined as 0.04 cm through a metal shield. 2 The Keithley 2400 was used as the power supply, controlled via LabView, at an illuminance of 100 mW / cm². 2 The voltage-current density characteristics of each component were measured under simulated sunlight conditions using an AM 1.5G microscope. In Table 1 below, Voc represents the open circuit voltage, Jsc represents the short-circuit current density, FF represents the fill factor, and PCE0 represents the initial energy conversion efficiency. Furthermore, the components were subjected to 100... o The efficiency value after heating at 100°C for 120 minutes is PCE1. Thermal stability is expressed as the ratio of efficiency (PCE1 / PCE0) before and after heating at 100°C for 120 minutes after component packaging. The closer the value is to 1.00, the better the thermal stability.

[0067] Table 1: Photoelectric properties of perovskite solar cells of the comparative group (C1) and the components containing the additives of this invention (E2A, E4A, and E7A). The results in Table 1 show that the comparative example component C1, without any additives, has an open-circuit voltage Voc of 1.070 V and a short-circuit current density Jsc of 20.35 mA / cm². 2 The fill factor FF is 80.8%, the initial power conversion efficiency PCE0 is 17.6%, and the thermal stability PCE1 / PCE0 is 79.77%. This shows that the efficiency of the perovskite optoelectronic device without additives degrades by about 20% after being treated at 100°C, reflecting the thermal instability problem caused by defect sites in the perovskite active layer.

[0068] The element E2A with the addition of PPI-BA (n-butyl additive) from Example 2 of this invention exhibits a Voc increase to 1.096 V (0.026 V higher than C1) and a Jsc of 20.21 mA / cm². 2The FF increased to 82.6%, and PCE0 reached 18.3%, an improvement of 0.7 percentage points compared to C1; the thermal stability PCE1 / PCE0 significantly improved to 98.91%, an improvement of approximately 19 percentage points compared to C1, indicating that the n-butyl R in PPI-BA... 0 The flexible segments imparted help improve the compactness and defect passivation effect of perovskite films, while the excellent film-forming properties and mechanical properties of the polymer backbone significantly contribute to the structural stability of the device under high-temperature conditions.

[0069] The element E4A with the addition of Example 4 of this invention (PPI-FBZA, 4-fluorobenzyl additive) exhibits an increased Voc to 1.096 V (0.026 V higher than C1) and an increased Jsc to 20.50 mA / cm². 2 (0.15 mA / cm² improvement over C1), FF is 80.6%, PCE0 reaches 18.1%, an improvement of 0.5 percentage points over C1; thermal stability PCE1 / PCE0 reaches 98.75%, an improvement of approximately 19 percentage points over C1. The benzyl type R of PPI-FBZA... 0 It has a benzene ring π-conjugated structure, which can generate π-π stacking interaction with the perovskite lattice. The F substituent at the 4-position of the benzene ring further enhances the additive's ability to coordinate and passivate defect sites such as lead vacancies, effectively suppressing non-radiative recombination, thus making the Jsc phase significantly improved compared with other additive groups.

[0070] The element E7A with the addition of Example 7 of this invention (PPI-FPEA, 4-fluorophenylethyl additive) showed an increase in Voc to 1.122 V (the highest among the three application examples, an increase of 0.052 V compared to C1) and Jsc to 20.98 mA / cm². 2 (0.63 mA / cm² higher than C1, the highest among the three groups), FF 79.5%, PCE0 18.7% (the highest among the three application groups, 1.1 percentage points higher than C1); thermal stability PCE1 / PCE0 reached 97.92%, an improvement of approximately 18 percentage points compared to C1. PPI-FPEA uses phenethyl R with a methylene chain length n=2. 0 Compared to the benzyl type with n=1, its longer methylene spacer segment gives the benzene ring greater spatial freedom, which is conducive to forming more effective multi-point coordination passivation with perovskite lattice defect sites. Furthermore, the 4-fluorosubstituted phenethyl structure may simultaneously regulate the energy level distribution of the additive, promoting the extraction efficiency of photogenerated carriers, thereby achieving the most significant improvement in both Voc and Jsc, with PCE0 showing the best performance among the three groups.

[0071] In summary, the additives (E2A, E4A, and E7A) containing poly[(phenyl isocyanate)-copolyoxymethylene] derivatives of this invention significantly improve energy conversion efficiency compared to the control element (C1) without additives, with PCE0 exceeding 18%. In terms of thermal stability, the PCE1 / PCE0 ratios of the three additive-containing elements all reach over 97%, far superior to C1's 79.77%. This fully demonstrates the dual technical advantages of polymer-type additives compared to small molecules, namely, simultaneously achieving the goals of performance improvement and long-term stability enhancement.

[0072] Comparison of component performance at different concentrations of various additives To further evaluate different R 0 The effect of different concentrations of poly[(phenyl isocyanate)-copolyoxymethylene] derivative additives (E1 to E7) on the performance of perovskite solar cells was investigated. Perovskite solar cells with different amounts of each additive (calculated as mg per milliliter of perovskite precursor solution) were prepared according to the aforementioned method. The Voc, Jsc, FF and PCE of each element were measured, and the results are shown in Table 2 below.

[0073] Table 2: Photoelectric properties of perovskite solar cells in Examples 1 to 7 (E1 to E7) and the control group (C1) at different additive concentrations. As can be observed from the results in Table 2, the additives (E1 to E7) in each embodiment of the present invention can affect the photoelectric properties of perovskite solar cells to varying degrees at appropriate concentrations. Among them, the performance improvement effects of Examples 2 (PPI-BA), 4 (PPI-FBZA), and 7 (PPI-FPEA) are the most significant. Specifically, the PCE of the device prepared by Example 2 (PPI-BA) at an addition concentration of about 1.0 mg / mL reached 18.3%, which is about 0.7 percentage points higher than the control group without additives (C1, PCE 17.6%); the PCE of the device prepared by Example 4 (PPI-FBZA) at an addition concentration of about 0.5 mg / mL reached 18.1%, which is about 0.5 percentage points higher; and the PCE of the device prepared by Example 7 (PPI-FPEA) at an addition concentration of about 2.0 mg / mL reached 18.7%, which is the highest among all experimental groups, with an improvement of about 1.1 percentage points. The above results show that each additive has an optimal concentration range. Excessive or insufficient addition may adversely affect the device performance, indicating that the performance improvement effect of the additives of the present invention is concentration-dependent, and the optimal concentrations of different R0 types of additives are different. Under the optimal concentration conditions, all additives can effectively passivate the defect sites of perovskite thin films, which confirms the importance of optimizing the amount of additives to achieve the best photoelectric performance.

[0074] The embodiments described above are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention, or reasonable combinations of features and solutions from various embodiments, are all within the scope of protection of the present invention.

Claims

1. An additive containing a poly[(phenyl isocyanate)-copolyoxymethylene] derivative, the derivative being of the following formula (I): in, R 0 Selected from C1 to C8 straight-chain, branched or cyclic alkyl groups that are unsubstituted or substituted with at least one F, or benzene alkyl groups on the benzene ring that are each independently selected from H, F or CF3 and have a methylene chain length n of 1 or 2.

2. The additive containing poly[(phenyl isocyanate)-copolyacetal] derivative as described in claim 1, wherein, R 0 As shown in equation (II): Among them, R 1 To R 5 Each is independently selected from H, F, or CF3; and n is 1 or 2.

3. The additive containing poly[(phenyl isocyanate)-copolyacetal] derivative as described in claim 1, wherein, R 0 It is an unsubstituted C1 to C8 straight-chain, branched or cyclic alkyl group.

4. The additive containing poly[(phenyl isocyanate)-copolyacetal] derivative as described in claim 1, wherein, R 0 It is a C1 to C8 straight-chain, branched or cyclic alkyl group that has been substituted with at least one F.

5. The additive containing poly[(phenyl isocyanate)-copolyacetal] derivative as described in claim 1, wherein, R 0 Selected from: Methyl (-CH3), n-Butyl(-n-C4H9, ), octyl (-n-C8H) 17 , ) 4-Fluorobenzyl(-CH2C6H4F, ), 4-(trifluoromethyl)benzyl(-CH2C6H4CF3, ), Phenylacetyl (-CH2CH2C6H5, ),or 4-Fluorophenylethyl (-CH2CH2C6H4F, ).

6. The use of an additive containing a poly[(phenyl isocyanate)-copolyoxymethylene] derivative as described in any one of claims 1 to 5 for preparing a perovskite active layer for a perovskite optoelectronic device.

7. The use as described in claim 6, wherein the additive is formed by modifying poly[(phenyl isocyanate)-copolyoxymethylene] to form the additive, and then crystallizing it in a perovskite precursor solution to form the perovskite active layer.

8. The use as described in claim 6, wherein the concentration of the additive in each milliliter of the perovskite precursor solution is from 0.1 mg to 5 mg.

9. The use as described in claim 6, wherein the perovskite active layer comprises HC(NH2)2I, CsI, PbI2 and PbBr2.

10. The use as described in claim 6, wherein the perovskite optoelectronic element is a perovskite solar cell, the perovskite solar cell comprising a substrate, a first electrode deposited on the substrate, a hole transport layer deposited on the first electrode, a perovskite active layer deposited on the hole transport layer, an electron transport layer deposited on the perovskite active layer, an electron modification layer deposited on the electron transport layer, and a second electrode deposited on the electron modification layer.

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