An imide molybdenum-oxygen cluster organic-inorganic hybrid material, its preparation method and application

Abstract

The present invention provides an imide molybdenum oxide cluster organic-inorganic hybrid material, a preparation method thereof and an application thereof, belonging to the technical field of organic solar cells. The present invention uses an imide structural unit as a modifying group and a simple-structured Lindqvist-type molybdenum oxide polyoxometalate cluster as the core structure. Polyoxometalate compounds have relatively high conductivity, while imide molecules have relatively high electron mobility and excellent electron transport ability. The composite formed by combining the Lindqvist-type molybdenum oxide cluster and the imide organic material has a relatively high conductivity, so the film thickness insensitivity of this material is good. The hybrid material has a simple and precise structure, strong modifiability, thickness insensitivity and high energy conversion efficiency. As an electron transport layer material, it can exhibit good performance and film thickness insensitivity in both fullerene acceptors and non-fullerene acceptors. Therefore, it has good universality in organic solar cells.

Description

Technical Field

[0001] The present invention relates to the technical field of organic solar cells, and particularly relates to an imide molybdenum oxide cluster organic-inorganic hybrid material, a preparation method thereof, and an application thereof. Background Art

[0002] In recent years, organic photovoltaics has developed vigorously, and its energy conversion efficiency has been increasing steadily. Against the backdrop of the Internet of Everything, organic photovoltaics has the advantages of light weight, solution processability, and roll-to-roll production, and has great application potential in fields such as wearable devices, the Internet of Things, and smart glass. Thanks to the continuous design and development of light-harvesting layer materials by researchers, the light-harvesting ability of organic solar cells has been continuously improved, and its energy conversion efficiency has exceeded 19%, which means that the industrialization process of organic solar cells has been further shortened. Although the light-harvesting ability of organic solar cells is very important, its ability to transport and extract charges cannot be ignored. The cathode interface layer is located between the active layer and the metal electrode, and can effectively reduce the Schottky barrier between the two and block the entry of holes, thereby very effectively promoting the charge transport and extraction process of organic solar cells. Among many cathode interface materials, organic-inorganic hybrid cathode interface materials have attracted much attention from researchers due to their advantages of being easy to process with green solvents like organic cathode interface materials and having high mobility like inorganic cathode interface materials. Among them, polyoxometalate-based cathode interface materials are highly favored. So far, there are not many reports on the application of polyoxometalates in organic solar cells as the cathode interface layer. The reason is that the types of materials used as the cathode interface layer are few, and most of them focus on Anderson or Keggin-type structures such as phosphomolybdic acid and silicotungstic acid. These materials generally have relatively complex structures, and there are deficiencies such as difficulty in organic post-modification and sensitivity to the film thickness of the organic cathode interface layer, resulting in large differences in device performance and low yield, which affects commercial production. Summary of the Invention

[0003] The purpose of the present invention is to provide an imide molybdenum oxide cluster organic-inorganic hybrid material, a preparation method thereof, and an application thereof, which has a simple and precise structure and is not sensitive to film thickness.

[0004] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0005] The present invention provides an imide molybdenum oxide cluster organic-inorganic hybrid material having the structure shown in Formula 1:

[0006]

[0007] In Formula 1, Ar is a polycyclic aromatic fused ring unit, R1 is methyl, ethyl or isopropyl; R2 is a straight-chain alkyl, a branched-chain alkyl or an aminoalkyl.

[0008] Preferably, the Ar is:

[0009]

[0010] Wherein, R3 is a C1-C12 linear alkyl group.

[0011] Preferably, the R2 is:

[0012]

[0013] Wherein, n = 1-18 and n is an integer; m = 1-6 and m is an integer.

[0014] The present invention provides a method for preparing the imide molybdenum-oxygen cluster organic-inorganic hybrid material described in the above technical solution, comprising the following steps:

[0015] Mix (Bu4N)4[α-Mo8O 26 , the compound 1 with the structure shown in Formula 2, a dehydrating agent and a first organic solvent, and carry out a dehydration reaction to obtain the compound 2 with the structure shown in Formula 3;

[0016] Mix the compound 2 with the structure shown in Formula 3, the compound 3 with the structure shown in Formula 4, a catalyst, a reducing agent and a second organic solvent, and carry out a Sonagashira reaction to obtain the imide molybdenum-oxygen cluster organic-inorganic hybrid material;

[0017]

[0018] Preferably, the dehydrating agent is dicyclohexylcarbodiimide or (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride).

[0019] Preferably, the molar ratio of (Bu4N)4[-Mo8O 26 , the compound 1 and the dehydrating agent is 1:(2.1-3.0):(1.0-3.0); the time of the dehydration reaction is 7-24 h, and the temperature is 85-120 °C.

[0020] Preferably, the catalyst is palladium dichloride bis(triphenylphosphine) and copper iodide; the molar ratio of palladium dichloride bis(triphenylphosphine) to copper iodide is 1:4; the molar amount of palladium dichloride bis(triphenylphosphine) is 3-5% of the molar amount of the compound 2, and the molar amount of copper iodide is 12-20% of the molar amount of the compound 2.

[0021] Preferably, the molar ratio of the compound 2 to the compound 3 is 1:(2.1-3.0); the reducing agent includes triethylamine.

[0022] Preferably, the temperature of the Sonagashira reaction is room temperature, and the time is 40-60 min.

[0023] The present invention provides the application of the imide molybdenum-oxygen cluster organic-inorganic hybrid material described in the above technical solution or the imide molybdenum-oxygen cluster organic-inorganic hybrid material prepared by the preparation method described in the above technical solution as an electron transport layer material in a solar cell.

[0024] The present invention provides an imide molybdenum-oxygen cluster organic-inorganic hybrid material, which uses an imide structural unit as a modifying group and a structurally simple Lindqvist-type molybdenum-oxygen polyoxometalate as the core structure. The Lindqvist-type molybdenum-oxygen cluster has an octahedral structure. It not only has electron transport properties but also can selectively obtain mono- and bifunctional post-modified derivatives. Molybdenum-oxygen clusters are essentially metal oxides with high chemical stability and high thermal stability themselves; while imide molecules are conjugated polycyclic molecules with good chemical stability and relatively high thermal stability. Therefore, the composite formed by the combination of the two exhibits high thermal stability. Polyoxometalate compounds have relatively high conductivity, while imide molecules have relatively high electron mobility and excellent electron transport ability. The composite formed by combining Lindqvist-type molybdenum-oxygen clusters and imide organic materials has relatively high conductivity. Therefore, the hybrid material provided by the present invention has good film thickness insensitivity, a simple and precise structure, adjustable structure, and high energy conversion efficiency. It can exhibit good performance and film thickness insensitivity in both fullerene acceptors and non-fullerene acceptors, and thus has good universality in organic solar cells.

[0025] The present invention provides a preparation method of the imide molybdenum-oxygen cluster organic-inorganic hybrid material. Through simple organic synthesis reactions and steps, an organic-inorganic hybrid electron transport layer material with good green solvent processability can be obtained, providing a guarantee for its application in solution-processed and roll-to-roll large-area production of organic solar cells. The results show that the imide molybdenum-oxygen cluster organic-inorganic hybrid material provided by the present invention has characteristics such as good thermal stability, insensitivity to film thickness, and high universality. With the change of the concentration and thickness (8 - 42 nm) of the transport layer material, the device can still maintain ideal photoelectric conversion efficiency and stable performance. The synthesis method of the present invention is simple and efficient, with good stability and repeatability, low cost, universality, and is easy to scale up production. Description of the Drawings

[0026] Figure 1 1H NMR spectrum of compound 4 in Example 1;

[0027] Figure 2 High-resolution mass spectrum of compound 4 in Example 1;

[0028] Figure 3J-V curves of the POM_PBIs electron transport layer at different film thicknesses based on the PM6:BTP-BO-4Cl system; (a) 8 nm, (b) 17 nm, (c) 26 nm, and (d) 41 nm;

[0029] Figure 4 External quantum efficiency (EQE) curves of the POM_PBIs electron transport layer at different film thicknesses based on the PM6:BTP-BO-4Cl system; (a) 8 nm, (b) 17 nm, (c) 26 nm, and (d) 41 nm;

[0030] Figure 5 J-V curves of the POM_PBIs electron transport layer at different film thicknesses based on the PTB7-Th:PC71BM system; (a) 11 nm, (b) 19 nm, (c) 28 nm, and (d) 42 nm;

[0031] Figure 6 EQE curves of the POM_PBIs electron transport layer at different film thicknesses based on the PTB7-Th:PC71BM system; (a) 11 nm, (b) 19 nm, (c) 28 nm, and (d) 42 nm;

[0032] Figure 7 AFM topography images of the POM_PBIs prepared in Example 1 in different systems; (a,b) PM6:BTP-BO-4Cl system, (c,d) PTB7-Th:PC71BM system, (a,c) AFM height images, (b,d) AFM phase images;

[0033] Figure 8 UV-Vis absorption spectra of the POM_PBIs prepared in Example 1 in the film and solution (acetonitrile) states (a), electron paramagnetic resonance spectra of the POM_PBIs and the POM_PBIs with different acceptors (b), cyclic voltammograms of the POM_PBIs (c), and thermogravimetric analysis diagrams of the POM_PBIs (d). Detailed implementation manners

[0034] The present invention provides an imide molybdenum oxo cluster organic-inorganic hybrid material with the structure shown in Formula 1:

[0035]

[0036] In Formula 1, Ar is a polycyclic aromatic fused ring unit, R1 is methyl, ethyl, or isopropyl; R2 is a straight-chain alkyl, a branched-chain alkyl, or an aminoalkyl.

[0037] In the present invention, the Ar is preferably:

[0038]

[0039] Among them, R3 is a straight-chain alkyl group with 1 to 12 carbon atoms.

[0040] In the present invention, the R2 is preferably:

[0041]

[0042] Among them, n = 1 to 18 and n is an integer; m = 1 to 6 and m is an integer.

[0043] The present invention provides a preparation method of the imide molybdenum-oxygen cluster organic-inorganic hybrid material described in the above technical solution, including the following steps:

[0044] Mix (Bu4N)4[α-Mo8O 26 , the compound 1 with the structure shown in Formula 2, a dehydrating agent and a first organic solvent, and carry out a dehydration reaction to obtain the compound 2 with the structure shown in Formula 3;

[0045] Mix the compound 2 with the structure shown in Formula 3, the compound 3 with the structure shown in Formula 4, a catalyst, a reducing agent and a second organic solvent, and carry out a Sonagashira reaction to obtain the imide molybdenum-oxygen cluster organic-inorganic hybrid material;

[0046]

[0047] In the present invention, unless otherwise specified, the raw materials required for preparation are all commercially available products well-known to those skilled in the art.

[0048] The present invention mixes (Bu4N)4[α-Mo8O 26 , the compound 1 with the structure shown in Formula 2, a dehydrating agent and a first organic solvent, and carries out a dehydration reaction to obtain the compound 2 with the structure shown in Formula 3.

[0049] In the present invention, the preparation method of the (Bu4N)4[α-Mo8O 26 preferably includes: dissolving (NH4)6Mo7O 24 ·4H2O in water, adding NBu4Br, stirring the reaction system at room temperature for 10 to 60 minutes, then performing suction filtration, washing with deionized water 2 to 3 times and ethanol 2 to 3 times in sequence, drying at 60 °C in a vacuum oven, taking out, heating and dissolving all the obtained crude product with acetonitrile, standing and cooling to precipitate crystals (for 2 to 3 days), performing suction filtration, washing the filter residue with acetonitrile 2 to 3 times and ether 2 to 3 times in sequence, and drying at 60 °C in a vacuum oven for 6 to 8 hours to obtain the target product of (Bu4N)4[-Mo8O 26 ; the (NH4)6Mo7O 24· The molar amount of 4H2O is 10 to 100 mmol, and the molar amount of NBu4Br is 2 to 5 times that of (NH4)6Mo7O 24 · 4H2O; based on the molar amount of 10 to 100 mmol of (NH4)6Mo7O 24 · 4H2O, the amount of water used is 10 mL to 1 L.

[0050] The present invention has no special limitation on the specific preparation process of (Bu4N)4[α-Mo8O 26 , and it can be carried out according to the methods disclosed in the art; in the examples of the present invention, specifically: 50 mL of deionized water was added to (NH4)6Mo7O 24 · 4H2O (15 g, 12 mmol), stirred until a clear solution was obtained, and NBu4Br (12 g, 37 mmol) was added slowly in batches. A white precipitate was immediately formed. After adding NBu4Br, the reaction system was stirred for another 30 min, and then immediately filtered by suction. It was washed 3 times with deionized water and 3 times with ethanol in sequence, dried at 60 °C in a vacuum oven, taken out, and the obtained crude product was completely dissolved by heating with acetonitrile, allowed to stand and cool, and crystals were slowly precipitated (for 3 days). It was filtered by suction, the filter residue was washed 3 times with acetonitrile and 3 times with ether in sequence, and dried at 60 °C in a vacuum oven for 8 h to obtain (Bu4N)4[-Mo8O 26 , and the yield was 96.3%.

[0051] In the present invention, the compound 1 having the structure shown in Formula 2 is:

[0052]

[0053] The present invention has no special limitation on the source of the compound 1, and it can be a commercially available product well-known in the art or obtained in a manner well-known in the art.

[0054] In the present invention, the dehydrating agent is preferably dicyclohexylcarbodiimide (DCC) or (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride) (EDC).

[0055] In the present invention, the molar ratio of (Bu4N)4[-Mo8O 26 , compound 1 and the dehydrating agent is preferably 1:(2.1 to 3.0):(1.0 to 3.0), and more preferably 1:2.1:2.1.

[0056] In the present invention, the first organic solvent is preferably acetonitrile; the present invention has no special limitation on the amount of the first organic solvent used, and it can be adjusted according to actual needs to ensure the smooth progress of the reaction.

[0057] The present invention has no special limitation on (Bu4N)4[α-Mo8O26 There are no special restrictions on the mixing of the compound 1 with the structure shown in Formula 2, the dehydrating agent, and the first organic solvent. The materials can be mixed evenly according to the processes well-known in the art.

[0058] In the present invention, the dehydration reaction is preferably carried out under nitrogen protection and reflux conditions; the time of the dehydration reaction is preferably 7 to 24 h, more preferably 12 h; the temperature is preferably 85 to 120 °C, more preferably 90 °C.

[0059] After completing the dehydration reaction, in the present invention, the obtained product system is preferably cooled to room temperature, and the by-products insoluble in the solvent are removed by suction filtration. The obtained filter residue is washed 3 times with acetonitrile, the filtrate is collected, the filtrate is rotary evaporated to dryness, the obtained product is separated by column chromatography with a dichloromethane-acetonitrile eluent with a volume ratio of 4:1. After the solvent of the obtained product is rotary evaporated, it is dissolved with pure dichloromethane, ether is added, layered, allowed to stand overnight, crystals are precipitated, suction filtered, the filter residue is washed 2 to 3 times with ether, and the filter residue is collected and dried in a vacuum oven at 40 °C for 6 to 8 h to obtain compound 2. The present invention has no special restrictions on other unmentioned condition parameters and can be carried out according to the processes well-known in the art.

[0060] After obtaining the compound 2 with the structure shown in Formula 3, the present invention mixes the compound 2 with the structure shown in Formula 3, the compound 3 with the structure shown in Formula 4, a catalyst, a reducing agent, and a second organic solvent, and carries out the Sonagashira reaction to obtain an imide molybdenum oxo cluster organic-inorganic hybrid material.

[0061] In the present invention, the compound 3 with the structure shown in Formula 4 is:

[0062]

[0063] The present invention has no special restrictions on the source of the compound 3, and it can be a commercially available product well-known in the art or obtained in a manner well-known in the art.

[0064] In the present invention, the catalyst is preferably dichlorobis(triphenylphosphine)palladium and copper iodide; the molar ratio of dichlorobis(triphenylphosphine)palladium to copper iodide is preferably 1:4; the molar amount of dichlorobis(triphenylphosphine)palladium is preferably 3 to 5% of the molar amount of the compound 2, more preferably 3 to 4%, and the molar amount of copper iodide is preferably 12 to 20% of the molar amount of the compound 2, more preferably 12 to 15%.

[0065] In the present invention, the reducing agent preferably includes triethylamine; in the present invention, triethylamine is used to play a reducing role to reduce divalent palladium to zero-valent palladium, enabling the regeneration of palladium. At the same time, triethylamine and the second organic solvent together serve as the solvent.

[0066] In the present invention, the second organic solvent preferably includes N,N-dimethylformamide (DMF).

[0067] In the present invention, the molar ratio of Compound 2 to Compound 3 is preferably 1:(2.1 - 3.0), more preferably 1:2.5; the volume ratio of the second organic solvent to the reducing agent is preferably (5 - 40):(1 - 8), more preferably 1:0.25; the concentration of Compound 2 in the second organic solvent is preferably 20 - 30 mg / mL, more preferably 24 mg / mL.

[0068] In the present invention, the process of mixing Compound 2, the compound of the structure shown in Formula 4 (Compound 3), the catalyst, the reducing agent, and the second organic solvent is preferably to mix Compound 3, the catalyst, the reducing agent, and the second organic solvent, stir at room temperature for 5 - 10 min, and then add Compound 2.

[0069] In the present invention, the Sonagashira reaction is preferably carried out under a nitrogen atmosphere; the temperature of the Sonagashira reaction is preferably room temperature, and the time is preferably 40 - 60 min.

[0070] After completing the Sonagashira reaction, in the present invention, it is preferably to filter the obtained product system to remove insoluble solids, extract the obtained filtrate with a mixed solvent of dichloromethane + water (the volume ratio of dichloromethane to water is 1:2), dry, filter, rotary evaporate the solvent, perform column chromatography separation using dichloromethane - acetonitrile with a volume ratio of 10:1 as the eluent, dissolve the obtained dark red solid product in an appropriate amount of dichloromethane, add anhydrous ether as a poor solvent, let stand overnight, filter, and dry in a vacuum oven at 60 °C for 6 - 8 h to obtain the imide molybdenum oxide cluster organic-inorganic hybrid material. The present invention has no special limitations on other unmentioned condition parameters and can be carried out according to the processes well-known in the art.

[0071] In the present invention, the preparation reaction formula of the imide molybdenum oxide cluster organic-inorganic hybrid material is as follows:

[0072]

[0073] The present invention provides the application of the imide molybdenum oxide cluster organic-inorganic hybrid material described in the above technical solution or the imide molybdenum oxide cluster organic-inorganic hybrid material prepared by the preparation method described in the above technical solution as an electron transport layer material in a solar cell. The present invention has no special limitations on the application method and can be applied according to the methods well-known in the art.

[0074] The present invention has no special limitations on the specific structure and composition of the solar cell, and any solar cell with a corresponding structure and composition well-known in the art can be used.

[0075] In the application examples of the present invention, the donor materials used in the solar cell devices are PM6 and PTB7-Th respectively, and the acceptor materials are BTP-BO-4Cl and PC 71 BM respectively, and their structures are as follows:

[0076]

[0077] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the embodiments in the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.

[0078] Example 1

[0079]

[0080] (1) Weigh (NH4)6Mo7O 24 ·4H2O (15 g, 12 mmol) into a 100 mL clean beaker, add 50 mL of deionized water, stir until a clear solution is obtained, and slowly add NBu4Br (12 g, 37 mmol) in batches. Immediately, a white precipitate is formed; after the addition is complete, the reaction system is stirred for another 30 min, then immediately filtered by suction. Subsequently, it is washed 3 times with deionized water and 3 times with ethanol, and then dried in a vacuum oven at 60 °C. After taking it out, all the obtained crude product is heated and dissolved with an appropriate amount of acetonitrile, allowed to stand and cool, and crystals are slowly precipitated (the process lasts for 3 days). Then it is filtered by suction, and the filter residue is washed 3 times with acetonitrile and 3 times with ether, and then dried in a vacuum oven at 60 °C for 8 h to obtain pure (Bu4N)4[-Mo8O 26 , and the yield is 96.3%.

[0081] (2) Weigh (Bu4N)4[-Mo8O 26 (1.08 g, 0.50 mmol) into a dry 50 mL Schlenk tube, add 8 mL of anhydrous acetonitrile, and then successively add the aromatic amine compound 1 (0.21 g, 1.05 mmol) and DCC (0.22 g, 1.05 mmol) with the above structure. Under nitrogen protection, reflux and react at 90 °C for 12 h; after the reaction system cools to room temperature, filter by suction to remove the by-products insoluble in the acetonitrile solution, and the obtained filter residue is washed 3 times with acetonitrile. The filtrate is collected and evaporated to dryness by rotary evaporation; the obtained product is separated by column chromatography with a dichloromethane-acetonitrile eluent with a volume ratio of 4:1. The solvent of the obtained product is evaporated by rotary evaporation, dissolved in pure dichloromethane, and an ether solution is added. After stratification, it is allowed to stand overnight, and crystals are precipitated. Then it is filtered by suction, and the filter residue is washed 2 - 3 times with ether. The filter residue is collected and dried in a vacuum oven at 40 °C for 8 h to obtain compound 2, and the yield is 85.8%.

[0082] 3) Weigh 80 mg (103 μmol) of compound 3 (PBI-Br) into a 50 mL Schlenk tube. Using dichlorobis(triphenylphosphine)palladium (Pd(PPh3)2Cl2, 1.23 μmol) and copper(I) iodide (CuI, 4.92 μmol) as catalysts, add 3 mL of ultradry DMF and 0.75 mL of ultradry triethylamine as reaction solvents. After stirring at room temperature for 10 min, add compound 2 (71 mg, 41 μmol). The entire reaction system is carried out under a nitrogen atmosphere and reacted at room temperature for 60 min. After the reaction is completed, extract with a mixed solvent of 20 mL of dichloromethane + 40 mL of water. Dry, filter, and rotary evaporate the solvent of the obtained product in sequence; perform column chromatography separation using DCM-acetonitrile with a volume ratio of 10:1 as the eluent. Dissolve the obtained dark red solid product in an appropriate amount of DCM, slowly add anhydrous ether, let it stand overnight, filter, and dry in a vacuum oven at 60 °C for 8 h to obtain the pure product compound 4, denoted as POM_PBIs, with a yield of 65%.

[0083] The 1H NMR and high-resolution mass spectrometry diagrams of compound 4 prepared in Example 1 are as Figures 1 - 2 shown, and the data are as follows:

[0084] 1 H NMR (300 MHz, CDCl3) δ (ppm) = 10.37 - 10.34 (d, 2H), 8.89 (s, 2H), 8.68 (s, 2H), 7.41 (s, 4H), 5.20 (s, 4H), 4.05 - 4.05 (d, 4H), 3.34 - 3.29 (t, 16H), 2.28 - 2.24 (br, 8H), 1.87 (br, 8H), 1.66 (br, 24H), 1.51 - 1.49 (t, 16H), 1.43 - 1.41 (d, 24H), 1.32 - 1.28 (m, 40H), 1.02 - 0.97 (t, 24H), 0.85 - 0.83 (m, 24H).

[0085] Application Example 1

[0086] Use the imide molybdenum-oxygen cluster organic-inorganic hybrid material prepared in Example 1 as an electron transport layer material for organic solar cell devices:

[0087] When the donor material is PM6 and the acceptor material is BTP-4Cl:

[0088] The cleaned indium tin oxide (ITO) glass substrate was treated with an ultraviolet ozone instrument for 30 minutes. The PEODT:PSS aqueous solution (product model AI4083) diluted 2-fold with deionized water in equal volume was filtered through a 22-micron pore size water-soluble filter head, and then spin-coated on the ITO substrate at a speed of 4000 revolutions per minute and annealed at 150 °C for 15 minutes to form a uniform and regular thin film. Subsequently, a chlorobenzene solution [CB + 0.4% DIO (DIO volume ratio), 1,8-diiodooctane (DIO)] with a PM6:BTP-BO-4Cl mass ratio of 1:1.2 (10 mg / mL, based on the concentration of the donor PM6) was spin-coated on PEDOT:PSS at a speed of 3000 revolutions per minute. The spin-coated active layer was thermally annealed at 80 °C for 5 minutes (thickness 110 nm). The POM_PBIs prepared in Example 1 were dissolved in an acetonitrile solvent and spin-coated on the active layer at a speed of 3500 revolutions per minute (0.5 - 3 mg / mL, thickness 8 - 41 nm) as the electron transport layer. Subsequently, Ag with a thickness of 100 nm was evaporated in a vacuum evaporation chamber as the metal electrode to obtain an organic solar cell device.

[0089] Performance Test

[0090] The performance parameters of the organic solar cell device prepared in Test Application Example 1 were tested. Under the conditions of AM1.5G and simulated sunlight with an intensity of 100 mW (instrument model Enlitech model SS-F5-3A), the J-V characteristic curve was tested using a Keithley 2400 current / voltage data source meter. EQE was tested by QE-R3011 (Enli Technology Co., Ltd.). The thickness of the photosensitive layer was measured with a step profiler (model Veeco DektakXT) at a force of approximately 3 mg.

[0091] Under the optimal conditions of the device (test area 0.04 cm 2 ), the measured results are shown in Figures 3 - 4 , Figure 3 are the J-V curve graphs of the POM_PBIs electron transport layer at different film thicknesses based on the PM6:BTP-BO-4Cl system; (a) 8 nm, (b) 17 nm, (c) 26 nm, and (d) 41 nm; Figure 4 are the external quantum efficiency (EQE) curve graphs of the POM_PBIs electron transport layer at different film thicknesses based on the PM6:BTP-BO-4Cl system; (a) 8 nm, (b) 17 nm, (c) 26 nm, and (d) 41 nm. The various parameters are shown in Table 1.

[0092] Table 1 Various Performances of the Organic Solar Cell

[0093]

[0094] As can be seen from Table 1 and Figures 3 - 4 it is known that the power conversion efficiency of the organic solar cell device using POM_PBIs as the electron transport layer material is 17.19%, and the energy conversion efficiency remains 14.83% under the condition that the film thickness is 41 nm, which proves that this material has potential application value in organic solar cells.

[0095] Application Example 2

[0096] The donor material is PTB7-Th, and the acceptor material is PC 71 BM:

[0097] (1) The cleaned ITO glass substrate was treated with an ultraviolet ozone instrument for 30 minutes. The PEODT:PSS aqueous solution diluted 2 times with deionized water was filtered through a 22-micron pore size water-soluble filter head, and then spin-coated on the ITO substrate at a speed of 4000 revolutions per minute and annealed at 150 °C for 15 minutes to form a uniform and regular film. The chloroform solution [CB + 3% DIO (DIO volume ratio)] with a mass ratio of PTB7-Th:PC 71 BM = 1:1.5 (10 mg / mL, based on the concentration of the donor PTB7-Th) was spin-coated on PEDOT:PSS at a speed of 2600 revolutions per minute. The spin-coated active layer was placed flat in a vacuum chamber and vacuum-treated for 30 mins (thickness 110 nm). The POM_PBIs prepared in Example 1 were dissolved in an acetonitrile solvent and spin-coated on the active layer at a speed of 3500 revolutions per minute (0.5 - 3 mg / mL, thickness 11 - 42 nm) as the electron transport layer, and Ag with a thickness of 100 nm was evaporated in a vacuum evaporation chamber as the metal electrode to obtain an organic solar cell device.

[0098] Performance testing was carried out according to the method of Application Example 1. Under the optimal conditions of the device (the test area is 0.04 cm 2 ), the measured results are shown in Figures 5 - 6 , Figure 5 which are J-V curve graphs of the POM_PBIs electron transport layer at different film thicknesses based on the PTB7-Th:PC71BM system; (a) 11 nm, (b) 19 nm, (c) 28 nm, and (d) 42 nm; Figure 6 which are EQE curve graphs of the POM_PBIs electron transport layer at different film thicknesses based on the PTB7-Th:PC71BM system; (a) 11 nm, (b) 19 nm, (c) 28 nm, and (d) 42 nm.

[0099] Its various parameters are shown in Table 2.

[0100] Table 2 Various performances of the solar cell

[0101]

[0102] As can be seen from Table 2 and Figures 5 - 6 it can be known that the photoelectric conversion efficiency of the organic solar cell device using POM_PBIs as the electron transport layer material is 9.84%, and the energy conversion efficiency remains 7.21% under the condition that the film thickness is 42 nm, which proves that this material has potential application value in fullerene-based organic solar cells.

[0103] Figure 7 AFM morphology diagrams of POM_PBIs prepared in Example 1 in different systems; (a, b) PM6:BTP-BO-4Cl system, (c, d) PTB7-Th:PC 71 BM system, (a, c) AFM height diagrams, (b, d) AFM phase diagrams. As can be seen from Figure 7 it, the organic solar cell electron transport layer material POM_PBIs has good film-forming properties on the active layer, and the morphology is regular and smooth, which is beneficial to the transport and extraction of electrons.

[0104] Figure 8 UV-visible absorption spectra (a) of the film obtained by spin-coating POM_PBIs prepared in Example 1 and the solution (acetonitrile) state, electron paramagnetic resonance spectra (b) of POM_PBIs and POM_PBIs with different acceptors, cyclic voltammogram (c) of POM_PBIs, and thermogravimetric analysis diagram (d) of POM_PBIs. As can be seen from Figure 8 (a) therein, the material POM_PBIs has different degrees of absorption at wavelengths of 400 - 700 nm (solution and film states); as can be seen from Figure 8 (b) therein, the material POM_PBIs can generate strong radical signals when mixed with the acceptors BTP-BO-4Cl and PC71BM, indicating that this material has a good doping effect with the active layer acceptor, thus being beneficial to electron transport; as can be seen from Figure 8 (c) therein, the energy levels of the material POM_PBIs can be well matched with the energy levels of the photoactive layer, further verifying the device results of the material; as can be seen from Figure 8 (d) therein, the material POM_PBIs has a relatively high thermal decomposition temperature, proving that this electron transport layer material has good thermal stability.

[0105] The above is only the preferred implementation manner of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. An imide molybdenum-oxygen cluster organic-inorganic hybrid material has the structure shown in Formula 1: In Formula 1, R1 is methyl, ethyl or isopropyl; The Ar is: Wherein, R3 is a C1-C12 linear alkyl group; The R2 is: wherein, n = 1-18 and n is an integer; m = 1-6 and m is an integer.

2. A preparation method of the imide molybdenum-oxygen cluster organic-inorganic hybrid material according to Claim 1, comprising the following steps: Mix (Bu4N)4[α-Mo8O 26 , the compound 1 with the structure shown in Formula 2, a dehydrating agent and a first organic solvent, and carry out a dehydration reaction to obtain the compound 2 with the structure shown in Formula 3; Mix the compound 2 with the structure shown in Formula 3, the compound 3 with the structure shown in Formula 4, a catalyst, a reducing agent and a second organic solvent, and carry out a Sonagashira reaction to obtain an imide molybdenum-oxygen cluster organic-inorganic hybrid material; 3. According to the preparation method described in Claim 2, characterized in that The dehydrating agent is dicyclohexylcarbodiimide or 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride.

4. According to the preparation method described in Claim 2 or 3, characterized in that The molar ratio of (Bu4N)4[α-Mo8O 26 , Compound 1 and the dehydrating agent is 1:(2.1 - 3.0):(1.0 - 3.0); the time of the dehydration reaction is 7 - 24 h, and the temperature is 85 - 120 °C.

5. According to the preparation method described in Claim 2, characterized in that The catalyst is palladium dichloride bis(triphenylphosphine) and copper(I) iodide; the molar ratio of palladium dichloride bis(triphenylphosphine) to copper(I) iodide is 1:4; the molar amount of palladium dichloride bis(triphenylphosphine) is 3-5% of the molar amount of the compound 2, and the molar amount of copper(I) iodide is 12-20% of the molar amount of the compound 2.

6. According to the preparation method described in Claim 2, characterized in that The molar ratio of the compound 2 to the compound 3 is 1:(2.1-3.0); the reducing agent includes triethylamine.

7. According to the preparation method described in Claim 2 or 5 or 6, characterized in that The temperature of the Sonagashira reaction is room temperature and the time is 40-60 min.

8. Application of the imide molybdenum-oxygen cluster organic-inorganic hybrid material according to Claim 1 or the imide molybdenum-oxygen cluster organic-inorganic hybrid material prepared by the preparation method described in any one of Claims 2 to 7 as an electron transport layer material in a solar cell.

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