Imide molybdenum oxide cluster-based organic-inorganic hybrid material and preparation method and use thereof

Abstract

A compound of formula (I): (I) wherein Ar is a polyphenyl ring-based aromatic fused ring unit; R1 is selected from the group consisting of methyl, ethyl, and isopropyl; and R2 is selected from the group consisting of linear alkyl, branched alkyl, and aminoalkyl. Preferably, each Ar is perylene, each R1 is i-propyl and each R2 is CH(C5H11)2. In the present disclosure, an imide structural unit is used as a modifying group, and a Lindqvist-type molybdenum oxide polyoxometalate with a simple structure is used as a core structure. The polyoxometalates have a high electrical conductivity, while the imide molecules have a high electron mobility and excellent electron transport capabilities. A composite obtained by combining the Lindqvist-type molybdenum oxide cluster and the imide-based organic materials has a desirable electrical conductivity. Therefore, the material has an excellent film thickness insensitivity. The hybrid material has a simple and precise structure, strong modifiability, insensitive thickness, and a high energy conversion efficiency. As an electron transport layer material, the hybrid material can exhibit desirable performances and insensitivity to film thickness in both fullerene acceptors and non-fullerene acceptors.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of organic solar cells, in particular to an imide molybdenum oxide cluster-based organic-inorganic hybrid material and a preparation method and use thereof. BACKGROUND

[0002] In recent years, organic photovoltaics have developed rapidly, and its energy conversion efficiency is steadily increased. Under the background of the Internet of Everything, organic photovoltaics have light weight, solution processing, and roll-to-roll production properties, and have a great application potential in wearable devices, the Internet of Things, and smart glass. Thanks to the continuous design and development of light-harvesting layer materials by researchers, a light-harvesting ability of organic solar cells has been continuously improved, with an energy conversion efficiency exceeding 19%. This means that the industrialization of organic solar cells is further shortened. Although the light-harvesting ability of organic solar cells is extremely 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, which can effectively reduce the Schottky barrier between the two layers and block the entry of electron holes, thereby effectively promoting the transport and extraction of organic solar cells for charges. Among the various cathode interface materials, organic-inorganic hybrid cathode interface materials have attracted the attention of researchers due to the easy processing of organic cathode interface materials with green solvents and the high mobility of inorganic cathode interface materials. Polyoxometalate-based cathode interface materials have been highly favored. So far, there are not many reports on use of the polyoxometalates as a cathode interface layer in organic solar cells. The reason is that there are few types of materials for polyoxometalates as the cathode interface layer, and most of these materials are concentrated in Anderson or Keggin structures such as phosphomolybdic acid and silicotungstic acid. Generally, these materials have a relatively complex structure, and have deficiencies such as difficulty in organic post-modification and sensitivity to the film thickness as an organic cathode interface layer, resulting in large differences in device performance and a low yield, which affects commercial production. SUMMARY

[0003] An objective of the present disclosure is to provide an imide molybdenum oxide cluster based organic-inorganic hybrid material and a preparation method and use thereof. The material has a simple and precise structure and is not sensitive to film thickness.

[0004] To achieve the above objective of the present disclosure, the present disclosure provides the following technical solutions.

[0005] The present disclosure provides an imide molybdenum oxide cluster-based organic- 15 1223 inorganic hybrid material, having a structure shown in formula 1: where in formula 1, Ar is a polyphenyl ring-based aromatic fused ring unit; Ri is selected from the group consisting of methyl, ethyl, and isopropyl; and R2 is selected from the group consisting of

[0007] C5H11       C11H23 ♦ —-{         * —€ C5H-1-1         C11H23 being an integer of 1 to 18, and m being an integer of 1 to 6.

[0008] Preferably, the Ar is selected from the group consisting of: 15 1223

[0010] and R3 is Ci to C12 linear alkyl.

[0011] The present disclosure further provides a preparation method of the imide molybdenum oxide cluster-based organic-inorganic hybrid material, including the following steps:

[0012] mixing (Bu4N)4[a-Mo8O26], a compound 1 having a structure shown in formula 2, a dehydrating agent, and a first organic solvent, and conducting dehydration to obtain a compound 2 having a structure shown in formula 3; and

[0013] mixing the compound 2 having a structure shown in formula 3, a compound 3 having a structure shown in formula 4, a catalyst, a reducing agent, and a second organic solvent, and conducting a Sonagashira reaction to obtain the imide molybdenum oxide cluster-based organic- inorganic hybrid material; where 2 Bu:$N formula 3; formula 4. 15 1223

[0015] Preferably, the dehydrating agent is selected from the group consisting of di cyclohexylcarbodiimide (DCC) and l-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC HC1).

[0016] Preferably, the (Bu4N)4[a-MosO26], the compound 1, and the dehydrating agent have a molar ratio of 1:(2.1-3.0):(1.0-3.0); and the dehydration is conducted at 85°C to 120°C for 7 h to 24 h.

[0017] Preferably, the catalyst includes dichlorobis(triphenylphosphine) palladium (II) and cuprous iodide; the dichlorobis(triphenylphosphine) palladium (II) and the cuprous iodide have a molar ratio of 1:4; the dichlorobis(triphenylphosphine) palladium (II) has a molar weight 3% to 5% that of the compound 2, and the cuprous iodide has a molar weight 12% to 20% that of the compound 2.

[0018] Preferably, the compound 2 and the compound 3 have a molar ratio of 1:(2.1-3.0); and the reducing agent includes triethylamine.

[0019] Preferably, the Sonagashira reaction is conducted at a room temperature for 40 min to 60 min.

[0020] The present disclosure further provides use of the imide molybdenum oxide cluster-based organic-inorganic hybrid material as an electron transport layer material in solar cells.

[0021] The present disclosure provides an imide molybdenum oxide cluster-based organic-inorganic hybrid material. An imide structure unit is used as a modifying group, and a Lindqvist-type molybdenum oxide polyoxometalate with a simple structure is used as a core structure. The Lindqvist-type molybdenum oxygen cluster is in a regular octahedral structure, which has electron transport properties and can selectively obtain mono- and bifunctional post-modified derivatives. The molybdenum oxide cluster is essentially a metal oxide, with high chemical stability and desirable thermal stability; and the imide molecule is a conjugated fused ring molecule, showing excellent chemical stability and high thermal stability. Therefore, a complex formed by the 15 1223 combination of the above two exhibits high thermal stability. Polyoxometalates have high electrical conductivity, while imide molecules have high electron mobility and excellent electron transport capabilities. A composite obtained by combining the Lindqvist-type molybdenum oxide cluster and the imide-based organic materials has a desirable electrical conductivity. Therefore, the hybrid material has a desirable insensitivity to film thickness, a simple, precise, and adjustable structure, and high energy conversion efficiency. As an electron transport layer material, the hybrid material can show excellent performances and insensitivity to film thickness in both fullerene acceptors and non-fullerene acceptors, thus showing desirable universality in organic solar cells.

[0022] The present disclosure further provides a preparation method of the imide molybdenum oxide cluster-based organic-inorganic hybrid material. In the present disclosure, an organic-inorganic hybrid electron transport layer material with high green-solvent processability can be obtained through simple organic synthesis reactions and steps, which guarantees use of the hybrid material in solution-processable, roll-to-roll, and large-area production of organic solar cells. The results show that the imide molybdenum oxide cluster-based organic-inorganic hybrid material has desirable thermal stability, insensitivity to film thickness, and high universality. With the change of material concentration and thickness (8 nm to 42 nm) of the transport layer, the device can still maintain ideal photoelectric conversion efficiency and stable performances. The synthesis method has simplicity and high efficiency, desirable stability and repeatability, low cost, universal applicability, and easy large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG. 1 shows a hydrogen nuclear magnetic resonance (HNMR) spectrum of a compound 4 obtained in Example 1;

[0024] FIG. 2 shows a high-resolution mass spectrogram of the compound 4 obtained in Example 1;

[0025] FIG. 3 shows a J-V curve of a POMPBIs electron transport layer based on a PM6:BTP-BO-4C1 system under different film thicknesses; where (a) is 8 nm, (b) is 17 nm, (c) is 26 nm, and (d) is 41 nm;

[0026] FIG. 4 shows an external quantum efficiency (EQE) curve of the POM PBIs electron transport layer based on the PM6:BTP-BO-4C1 system under different film thicknesses; where (a) is 8 nm, (b) is 17 nm, (c) is 26 nm, and (d) is 41 nm;

[0027] FIG. 5 shows a J-V curve of the POM PBIs electron transport layer based on a PTB7-Th:PC71BM system under different film thicknesses; where (a) is 11 nm, (b) is 19 nm, (c) is 28 nm, and (d) is 42 nm;

[0028] FIG. 6 shows an EQE curve of the POMPBIs electron transport layer based on the PTB7- Th:PC71BM system under different film thicknesses; where (a) is 11 nm, (b) is 19 nm, (c) is 28 nm, and (d) is 42 nm;

[0029] FIG. 7 shows AFM morphology of the POMPBIs prepared in Example 1 in different systems; where (a, b) is the PM6:BTP-BO-4C1 system, (c, d) is the PTB7-Th:PC7iBM system, (a, c) is an AFM height map, and (b, d) is an AFM phase map; and

[0030] FIG. 8 shows an ultraviolet-visible absorption spectrum (a) of the POM PBIs prepared in Example 1 in a state of film and solution (acetonitrile), an electron paramagnetic resonance spectrum (b) of the POM PBIs and POM PBIs with different acceptors, a cyclic voltammetry curve (c) of the POM PBIs, and a thermogravimetric analysis chart (d) of the POM PBIs. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] The present disclosure provides an imide molybdenum oxide cluster-based organic- 15 1223 inorganic hybrid material, having a structure shown in formula 1:

[0033] where in formula 1, Ar is a polyphenyl ring-based aromatic fused ring unit; Ri is selected from the group consisting of methyl, ethyl, and isopropyl; and R2 is selected from the group consisting of linear alkyl, branched alkyl, and aminoalkyl.

[0034] In the present disclosure, the Ar is preferably selected from the group consisting of: 15 1223

[0036] and R3 is Ci to C12 linear alkyl.

[0037] In the present disclosure, the R2 is preferably selected from the group consisting of: C11H23             | \

[0038] , CsH” ,                .and              ,

[0039] and n is an integer of 1 to 18; m is an integer of 1 to 6.

[0040] The present disclosure further provides a preparation method of the imide molybdenum oxide cluster-based organic-inorganic hybrid material, including the following steps:

[0041] mixing (Bu4N)4[a-Mo8O26], a compound 1 having a structure shown in formula 2, a dehydrating agent, and a first organic solvent, and conducting dehydration to obtain a compound 2 having a structure shown in formula 3; and

[0042] mixing the compound 2 having a structure shown in formula 3, a compound 3 having a structure shown in formula 4, a catalyst, a reducing agent, and a second organic solvent, and conducting a Sonagashira reaction to obtain the imide molybdenum oxide cluster-based organic-inorganic hybrid material; where 15 1223

[0044] In the present disclosure, unless otherwise specified, all raw materials required for preparation are commercially available products well known to persons skilled in the art.

[0045] In the present disclosure, (Bu4N)4[a-Mo8O26], a compound 1 having a structure shown in formula 2, a dehydrating agent, and a first organic solvent are mixed, and dehydration is conducted to obtain a compound 2 having a structure shown in formula 3.

[0046] In the present disclosure, a preparation method of (Bu4N)4[a-Mo8O26] preferably includes: dissolving (NH4)eMo7O24*4H2O in water, adding NBu4Br, stirring an obtained reaction system at a room temperature for 10 min to 60 min, conducting suction filtration, and washing 2 to 3 times with deionized water and 2 to 3 times with ethanol successively, drying in a vacuum oven at 60 °C, and collecting a crude product; heating and dissolving the crude product with acetonitrile, allowing to stand for cooling, and separating out crystals (continuing for 2 d to 3 d), and conducting suction filtration; washing an obtained filter residue with acetonitrile for 2 to 3 times and with diethyl ether for 2 to 3 times successively, and drying in a vacuum oven at 60°C for 6 h to 8 h to obtain a target product of the (Bu4N)4[a-Mo8O26]; where the (NH4)eMo7O24*4H2O has a molar weight of 10 mmol to 100 mmol, and the NBu4Br has a molar weight 2 to 5 times that of the (NH4)eMo7O24*4H2O; and based on the molar weight of the (NH4)eMo7O24*4H2O at 10 mmol to 100 mmol, 10 mL to 1 L of water is used. 15 1223

[0047] In the present disclosure, there is no special limitation on a specific preparation process of the (Bu4N)4[a-Mo8O26], which can be conducted according to methods disclosed in the art. In an example, the method includes specifically: adding 50 mL of deionized water to the (NH4)eMo7O24*4H2O (15 g, 12 mmol), and stirring to obtain a clear solution; adding the NBu4Br (12 g, 37 mmol) slowly in portions, to obtain a white precipitate immediately; after adding the NBu4Br, stirring an obtained reaction system for another 30 min, conducting suction filtration immediately, washing with deionized water for 3 times and ethanol for 3 times, and drying in a vacuum oven at 60°C to collect a crude product; dissolving the crude product by heating with acetonitrile, allowing to stand for cooling, and precipitating crystals slowly (for 3 d), and conducting suction filtration; washing a resulting filter residue 3 times with acetonitrile and then 3 times with diethyl ether, and drying in a vacuum oven at 60°C for 8 h to obtain the (Bu4N)4[a-MosChe] with a yield of 96.3%.

[0048] In the present disclosure, the compound 1 having a structure shown in formula 2 is:

[0049] formula 2.

[0050] In the present disclosure, there is no special limitation on a source of the compound 1, which can be obtained from commercially available products or prepared by methods known in the art.

[0051] In the present disclosure, the dehydrating agent is preferably selected from the group consisting of dicyclohexylcarbodiimide (DCC) and l-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC HC1).

[0052] In the present disclosure, the (Bu4N)4[a-Mo8O26], the compound 1, and the dehydrating agent have a molar ratio of preferably 1:(2.1-3.0):(1.0-3.0), more preferably 1:2.1:2.1.

[0053] In the present disclosure, the first organic solvent is preferably acetonitrile; there is no special limitation on an amount of the first organic solvent, which can be adjusted according to actual needs to ensure a smooth progress of the reaction.

[0054] In the present disclosure, there is no special limitation on mixing the (Bu4N)4[a-Mo8O26], 15 1223 the compound 1 with a structure shown in formula 2, the dehydrating agent, and the first organic solvent, and the materials are mixed evenly according to the well-known methods in the art.

[0055] In the present disclosure, the dehydration is conducted preferably under nitrogen protection + reflux conditions at preferably 85°C to 120°C, more preferably 90°C for preferably 7 h to 24 h, more preferably 12 h.

[0056] In the present disclosure, after the dehydration is completed, preferably an obtained product system is cooled to a room temperature, and solvent-insoluble by-products are removed by suction filtration; an obtained filter residue is washed 3 times with acetonitrile, and a filtrate is collected; the filtrate is removed by rotary evaporation, and a resulting product is separated by column chromatography with a dichloromethane-acetonitrile eluent at a volume ratio of 4:1; an obtained product is subjected to rotary evaporation to remove the solvent, dissolved in pure dichloromethane, added with diethyl ether, layered, and allowed to stand overnight; crystals are precipitated, and subjected to suction filtration, a filter residue is washed with diethyl ether for 2 to 3 times, and the filter residue is collected and dried in a vacuum oven at 40°C for 6 h to 8 h to obtain the compound 2. There is no special limitation on other conditional parameters not mentioned, and the reaction can be conducted according to the process well known in the art.

[0057] In the present disclosure, the compound 2 having a structure shown in formula 3, a compound 3 having a structure shown in formula 4, a catalyst, a reducing agent, and a second organic solvent are mixed, and a Sonagashira reaction is conducted to obtain the imide molybdenum oxide cluster-based organic-inorganic hybrid material.

[0058] In the present disclosure, the compound 3 having a structure shown in formula 4 is: I Ar rar

[0059] 1           formula 4.

[0060] In the present disclosure, there is no special limitation on a source of the compound 3, which can be obtained from commercially available products or prepared by methods known in the art.

[0061] In the present disclosure, the catalyst includes preferably dichlorobis(triphenylphosphine) palladium (II) and cuprous iodide; the dichlorobis(triphenylphosphine) palladium (II) and the 15 1223 cuprous iodide have a molar ratio of preferably 1:4; the dichlorobis(triphenylphosphine) palladium (II) has a molar weight preferably 3% to 5%, more preferably 3% to 4% that of the compound 2, and the cuprous iodide has a molar weight preferably 12% to 20%, more preferably 12% to 15% that of the compound 2.

[0062] In the present disclosure, the reducing agent includes preferably triethylamine; the triethylamine exerts a reducing effect to reduce divalent palladium to zero-valent palladium, such that palladium can be regenerated. Meanwhile, the triethylamine and the second organic solvent are jointly used as a solvent.

[0063] In the present disclosure, the second organic solvent includes preferably N, N-dimethylformamide (DMF).

[0064] In the present disclosure, the compound 2 and the compound 3 have a molar ratio of preferably 1:(2.1-3.0), more preferably 1:2.5; the second organic solvent and the reducing agent have a volume ratio of preferably (5-40):(1-8), more preferably 1:0.25; and the compound 2 in the second organic solvent has a concentration of preferably 20 mg / mLto 30 mg / mL, more preferably 24 mg / mL.

[0065] In the present disclosure, the mixing of the compound 2, the compound 3 having a structure shown in formula 4, the catalyst, the reducing agent, and the second organic solvent includes preferably: mixing the compound 3, the catalyst, the reducing agent, and the second organic solvent, stirring at a room temperature for 5 min to 10 min, and adding the compound 2.

[0066] In the present disclosure, the Sonagashira reaction is conducted preferably under a nitrogen atmosphere at preferably a room temperature for preferably 40 min to 60 min.

[0067] In the present disclosure, after the Sonagashira reaction is completed, a resulting product system is preferably filtered to remove insoluble solids; an obtained filtrate is extracted with a mixed solvent of dichloromethane + water (a volume ratio of the dichloromethane and water is 1:2), dried, filtered, subjected to rotary evaporation to remove the solvent, and separated by column chromatography with dichloromethane-acetonitrile as an eluent in a volume ratio of 10:1; an obtained dark red solid product is dissolved with an appropriate amount of dichloromethane, added with anhydrous diethyl ether as a poor solvent, allowed to stand overnight, and filtered; a product is dried in a vacuum oven at 60°C for 6 h to 8 h to obtain the imide molybdenum oxide clusterbased organic-inorganic hybrid material. There is no special limitation on other conditional parameters not mentioned, and the reaction can be conducted according to the process well known in the art.

[0068] In the present disclosure, a preparation reaction formula of the imide molybdenum oxide cluster-based organic-inorganic hybrid material is:

[0069]

[0070] The present disclosure further provides use of the imide molybdenum oxide cluster-based organic-inorganic hybrid material or an imide molybdenum oxide cluster-based organic-inorganic hybrid material prepared by the preparation method as an electron transport layer material in a solar cell. In the present disclosure, there is no special limitation on a method of the use, and methods well known in the art can be used.

[0071] In the present disclosure, there is no special limitation on specific structure and composition of the solar cell, and solar cells with corresponding structures and compositions well known in the art can be used.

[0072] In a use example of the present disclosure, in a solar cell device, donor materials are PM6 and PTB7-Th, respectively, and acceptor materials are BTP-BO-4C1 and PC71BM, respectively, with their structures as follows: 15 1223

[0073]

[0074] The technical solutions of the present disclosure will be described below clearly and completely in conjunction with the examples of the present disclosure. Apparently, the described examples are only a part of, not all of, the examples of the present disclosure. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present disclosure without creative efforts shall fall within the protection scope of the present disclosure.

[0075] Example 1 15 1223

[0076] (Bu4N)4[a-MogO26] (NH4)6Mo7O24’4H2O + NBu4Br 15 1223

[0077] (1) (NH4)6Mo?O24*4H2O (15 g, 12 mmol) was added to a clean 100 mL beaker, added with 50 mL of deionized water, and stirred to obtain a clear solution; NBu4Br (12 g, 37 mmol) was slowly added in portions, and a white precipitate was immediately formed; after the addition, an obtained reaction system was stirred for another 30 min, subjected to suction filtration immediately, washed with deionized water for 3 times and then ethanol for 3 times, dried in a vacuum oven at 60 °C, and a crude product was collected; the crude product was dissolved by heating with an appropriate amount of acetonitrile, allowed to stand for cooling, and crystals were slowly precipitated (for 3 d), and subjected to suction filtration; a filter residue was washed 3 times with acetonitrile and then 3 times with diethyl ether, and dried in a vacuum oven at 60°C for 8 h to obtain pure (Bu4N)4[a-MosO26] with a yield of 96.3%.

[0078] (2) (Bu4N)4[a-MosO26] (1.08 g, 0.50 mmol) was added into a dry 50 mL Shrek tube, added with 8 mL of anhydrous acetonitrile, and then added with an aromatic amine compound 1 with a structure shown above (0.21 g, 1.05 mmol) andDCC (0.22 g, 1.05 mmol) in sequence, refluxed at 90 °C for 12 h under nitrogen protection; an obtained product system was cooled to a room temperature, and solvent-insoluble by-products were removed by suction filtration; an obtained filter residue was washed 3 times with acetonitrile, and a filtrate was collected; the filtrate was removed by rotary evaporation, and a resulting product was separated by column chromatography with a dichloromethane-acetonitrile eluent at a volume ratio of 4:1; an obtained product was subjected to rotary evaporation to remove the solvent, dissolved in pure di chloromethane, added with a diethyl ether solution, layered, and allowed to stand overnight; crystals were precipitated, and subjected to suction filtration; a filter residue was washed with diethyl ether for 2 to 3 times, and the filter residue was collected and dried in a vacuum oven at 40°C for 8 h to obtain the compound 2, with a yield of 85.8%.

[0079] 3) A compound 3 (PBI-Br) (80 mg, 103 pmol) was added into a 50 mL Shrek tube, dichlorobis(triphenylphosphine) palladium (II) (Pd (PPhs^Ch, 1.23 pmol) and cuprous iodide (Cui, 4.92 pmol) were used as catalysts, 3 mL of ultra-dry DMF and 0.75 mL of ultra-dry tri ethylamine were added as reaction solvents, a mixture was stirred at a room temperature for 10 min, and added with the compound 2 (71 mg, 41 pmol); a whole reaction system was reacted at a room temperature for 60 min under a nitrogen atmosphere; a reaction product was extracted with a mixed solvent including 20 mL of dichloromethane + 40 mL of water, and a resulting extraction product was dried, filtered, and subjected to rotary evaporation to remove the solvent; an obtained product was separated by column chromatography using DCM-acetonitrile with a volume ratio of 10:1 as an eluent, and an obtained dark red solid product was dissolved in an appropriate amount of DCM, added with anhydrous diethyl ether slowly, allowed to stand overnight, filtered, and dried in a vacuum oven at 60°C for 8 h, to obtain a pure product compound 4, denoted as POM PBIs, 15 1223 with a yield of 65%.

[0080] The H1 NMR spectrum and high-resolution mass spectrum of the compound 4 prepared in Example 1 were shown in FIG. 1 to FIG. 2, and the data were as follows:

[0081] 'H NMR (300 MHz, CDC13) 8 (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).

[0082] Use Example 1

[0083] The imide molybdenum oxide cluster-based organic-inorganic hybrid material prepared in Example 1 was used as an electron transport layer material for organic solar cell devices:

[0084] When a donor material was PM6 and an acceptor material was BTP-4C1:

[0085] A cleaned indium tin oxide (ITO) glass substrate was treated with a UV-ozone instrument for 30 min; a PEDOT:PSS aqueous solution (AI 4083) diluted 2 times with deionized water in an equal volume was filtered by a water-soluble filter head with a pore size of 22 microns; the solution was spin-coated on the ITO substrate at 4,000 r / min and anneal at 150°C for 15 min to form a uniform and regular film. A chlorobenzene solution [CB+0.4%DIO (DIO in volume ratio), (DIO) was 1,8-diiodooctane] containing PM6 and BTP-BO-4C1 at a mass ratio of 1:1.2 (10 mg / mL, based on a concentration of the donor PM6) was spin-coated on PEDOT:PSS at 3,000 rpm, and a spin-coated active layer was thermally annealed at 80°C for 5 min (with a thickness of 110 nm). The POMPBIs prepared in Example 1 was dissolved in an acetonitrile solvent and spin-coated on the active layer (at 0.5 mg / mL to 3 mg / mL, with a thickness of 8 nm to 41 nm) at 3,500 rpm as an electron transport layer, and then subjected to chemical vapor deposition with Ag at a thickness of 100 nm in a vacuum vapor deposition chamber as a metal electrode to obtain an organic solar cell device.

[0086] Performance testing

[0087] The performance parameters of the organic solar cell device prepared in Use Example 1 were tested. Under the simulated sunlight of AM1.5 G and 100 mW intensity (instrument model: Enlitech model SS-F5-3A), a J-V characteristic curve was tested using a Keithley 2400 current / voltage data source meter. EQE was tested with QE-R3011 (Enli Technology Co., Ltd.). The thickness of the photosensitive layer was measured with a step meter (model: Veeco Dektak XT) at a force of about 3 mg.

[0088] Under optimal conditions of the device (the test area was 0.04 cm2), the measured results were shown in FIG. 3 to FIG. 4. FIG. 3 showed the J-V curve of a POM PBIs electron transport layer based on a PM6:BTP-BO-4C1 system under different film thicknesses; where (a) was 8 nm, (b) was 17 nm, (c) was 26 nm, and (d) was 41 nm; FIG. 4 showed the EQE curve of the POM PBIs electron transport layer based on the PM6:BTP-BO-4C1 system under different film thicknesses; where (a) was 8 nm, (b) was 17 nm, (c) was 26 nm, and (d) was 41 nm. The parameters were shown in Table 1. 15 1223

[0089] Table 1 Various performance parameters of organic solar cells

[0090] Concentration Thickness (nm) Open-circuit voltage (V) Short-circuit current density (mA / cm2) Calibration current ("mA / cm2) Fill factor (%) Photoelectric conversion efficiency 0.5 mg / mL 8 0.840 (0.841±0.002) 26.11 (25.83i0.24) 25.02 71.09 (70.25i0.56) 15.59 (15.25i0.25) 1 mg / mL 17 0.856 (0.854±0.003) 26.48 (26.58±0.14) 25.50 75.85 (75.38i0.39) 17.19 (17.11i0.05) 2 mg / mL 26 0.856 (0.851±0.003) 26.33 (26.39±0.07) 25.08 72.50 (72.33i0.30) 16.34 (16.25i0.05) 3 mg / mL 41 0.852 (0.852±0.002) 25.56 (25.55i0.23) 24.33 68.08 (67.41±0.75) 14.83 (14.68i0.09)

[0091] From Table 1 and FIG. 3 to FIG. 4, it was seen that the organic solar cell device using POMPBIs as the electron transport layer material had a photoelectric conversion efficiency of 17.19%, and could still maintain an energy conversion efficiency of 14.83% under a film thickness of 41 nm, proving that the material had a potential application value in the organic solar cells.

[0092] Use Example 2

[0093] A donor material was PTB7-Th, and an acceptor material was PC71BM:

[0094] (1) A cleaned ITO glass substrate was treated with a UV-ozone instrument for 30 min; a PEDOT:PSS aqueous solution diluted 2 times with deionized water was filtered by a water-soluble filter head with a pore size of 22 microns; the solution was spin-coated on the ITO substrate at 4,000 r / min and anneal at 150 °C for 15 min to form a uniform and regular film. A chlorobenzene solution [CB+3%DIO (DIO in volume ratio)] containing PTB7-Th and PC71BM at a mass ratio of 1:1.5 (10 mg / mL, based on a concentration of the donor PTB7-Th) was spin-coated on PEDOT:PSS at 2,600 rpm, and a spin-coated active layer was treated in a vacuum chamber for 30 min (with a thickness of 110 nm). The POM PBIs prepared in Example 1 was dissolved in an acetonitrile solvent and spin-coated on the active layer (at 0.5 mg / mL to 3 mg / mL, with a thickness of 11 nm to 42 nm) at 3,500 rpm as an electron transport layer, and then subjected to chemical vapor deposition with Ag at a thickness of 100 nm a vacuum vapor deposition chamber as a metal electrode to obtain an organic solar cell device.

[0095] The performance test was conducted according to the method of Use Example 1. Under optimal condition of the device (the test area was 0.04 cm2), the measured results were shown in FIG. 5 to FIG. 6. FIG. 5 showed the J-V curve of the POMPBIs electron transport layer based on a PTB7-Th:PC7iBM system under different film thicknesses; where (a) was 11 nm, (b) was 19 nm, (c) was 28 nm, and (d) was 42 nm; FIG. 6 showed the EQE curve of the POM PBIs electron transport layer based on the PTB7-Th:PC7iBM system under different film thicknesses; where (a) was 11 nm, (b) was 19 nm, (c) was 28 nm, and (d) was 42 nm.

[0096] The parameters were shown in Table 2.

[0097] Table 2 Various performance parameters of solar cells 15 1223

[0098] Concentr ation Film thickness (nm) Open-circuit voltage (V) Short-circuit current density (mA / cm2) Calibration current (mA / cm2) Fill factor (%) Photoelectric conversion efficiency (%) 0.5 mg / mL 11 0.786 (0.783±0.00 3) 15.49 (15.51±0.16) 15.39 65.99(64.97±0 .96) 8.03(7.89±0.09) 1 mg / mL 19 0.796 (0.793±0.00 3) 16.85 (16.74±0.17) 16.37 72.53 (70.63±l.ll) 9.73 (9.372±0.15) 2 mg / mL 28 0.797(0.797 ±0.003) 15.53(15.24±0.19) 14.97 64.19(63.15±1 .12) 7.94(7.66±0.18) 3 mg / mL 42 0.796(0.794 ±0.006) 15.20(15.15±0.09) 14.59 59.61(57.91±1 .38) 7.21(6.97±0.23)

[0099] From Table 2 and FIG. 5 to FIG. 6, it was seen that the organic solar cell device using POM PBIs as the electron transport layer material had a photoelectric conversion efficiency of 9.73%, and could still maintain an energy conversion efficiency of 7.21% under a film thickness of 42 nm, proving that the material had a potential application value in fullerene-based organic solar cells.

[0100] FIG. 7 showed AFM morphology of the POM PBIs prepared in Example 1 in different systems; where (a, b) was the PM6:BTP-BO-4C1 system, (c, d) was the PTB7-Th:PC7iBM system, (a, c) was an AFM height map, and (b, d) was an AFM phase map. It was seen from FIG. 7 that the electron transport layer material POM PBIs of organic solar cells had desirable film-forming properties and a regular and smooth appearance on the active layer, which was conducive to the transport and extraction of electrons.

[0101] FIG. 8 showed an ultraviolet-visible absorption spectrum (a) of the POM PBIs prepared in Example 1 in a state of film and solution (acetonitrile), an electron paramagnetic resonance spectrum (b) of the POM PBIs and POM PBIs with different acceptors, a cyclic voltammetry curve (c) of the POM PBIs, and a thermogravimetric analysis chart (d) of the POM PBIs. It was seen from (a) in FIG. 8 that the material POM PBIs had different degrees of absorption (solution and film state) at a wavelength of400 nm to 700 nm. It was seen from (b) in FIG. 8 that the material POMPBIs mixed with the acceptors BTP-B0-4C1 and PC71BM could generate a stronger free radical signal, indicating that the material had a desirable doping effect with the active layer acceptor, which was beneficial to transport of electrons. It was seen from (c) in FIG. 8 that the energy level of the material POM PBIs could match well with the energy level of the photoactive layer, further verifying the device results of the material. It was seen from (d) in FIG. 8 that the material POM PBIs had a relatively-high thermal decomposition temperature, indicating that the electron transport layer material had a high thermal stability.

[0102] The above descriptions are merely preferred implementations of the present disclosure. It should be noted that a person of ordinary skill in the art may further make several improvements and modifications without departing from the principle of the present disclosure, but such improvements and modifications should be deemed as falling within the protection scope of the present disclosure. 15 1223

Claims

1. An imide molybdenum oxide cluster-based organic-inorganic hybrid material, having a structure shown in formula 1:15 1223r2 formula 1;wherein Ar is a polyphenyl ring-based aromatic fused ring unit; Ri is selected from the groupconsisting of methyl, ethyl, and isopropyl; and R2 is selected from the group consisting ofC5Hl1                           |C11H23    .n being an integer of 1 to 18, and m being an integer of 1 to 6.

2. The imide molybdenum oxide cluster-based organic-inorganic hybrid material according toclaim 1, wherein the Ar is selected from the group consisting of:and R3 is Ci to C12 linear alkyl.15 12233. A preparation method of the imide molybdenum oxide cluster-based organic-inorganic hybrid material according to claim 1 or claim 2, comprising the following steps:mixing (Bu4N)4[a-Mo8O26], a compound 1 having a structure shown in formula 2, a dehydrating agent, and a first organic solvent, and conducting dehydration to obtain a compound 2 having a structure shown in formula 3; andmixing the compound 2 having a structure shown in formula 3, a compound 3 having a structure shown in formula 4, a catalyst, a reducing agent, and a second organic solvent, andconducting a Sonagashira reaction to obtain the imide molybdenum oxide cluster-based organic-inorganic hybrid material; whereinformula 2;4. The preparation method according to claim 3, wherein the dehydrating agent is selected from the group consisting of dicyclohexylcarbodiimide (DCC) and l-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC HC1).

5. The preparation method according to claim 3 or 4, wherein the (Bu4N)4[a-MosO26], the compound 1, and the dehydrating agent have a molar ratio of 1:(2.1-3.0):(1.0-3.0); and the dehydration is conducted at 85 °C to 120 °C for 7 h to 24 h.

6. The preparation method according to claim 3, wherein the catalyst comprises dichlorobis(triphenylphosphine) palladium (II) and cuprous iodide; the dichlorobis(triphenylphosphine) palladium (II) and the cuprous iodide have a molar ratio of 1:4; the dichlorobis(triphenylphosphine) palladium (II) has a molar weight 3% to 5% that of thecompound 2, and the cuprous iodide has a molar weight 12% to 20% that of the compound 2.

7. The preparation method according to claim 3, wherein the compound 2 and the compound 3 have a molar ratio of 1 :(2.1-3.0); and the reducing agent comprises triethylamine.

8. The preparation method according to claim 3, 6, or 7, wherein the Sonagashira reaction is conducted at a room temperature for 40 min to 60 min.

9. Use of the imide molybdenum oxide cluster-based organic-inorganic hybrid material according to claim 1 or claim 2 as an electron transport layer material in a solar cell.15 1223

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