Solar cell additive and preparation method and application thereof

Abstract

The invention discloses a solar cell additive and a preparation method and application thereof, and belongs to the technical field of organic photoelectric devices. According to the application of siloxane in the solar cell additive, siloxane has the following structural formula, Ar is an aromatic unit and comprises an electron-rich conjugated unit or an electron-deficient conjugated unit; r is selected from alkylene of C1-10, alkyleneoxy of C1-10, alkylenesulfenyl of C1-10, and alkylene group of C1-10; siO is a siloxy group; and n is the number of silicon and oxygen in a side chain and is equal to 1-4. The invention provides a siloxane additive which can be used in an active layer of an organic semiconductor device and can effectively promote exciton dissociation and transportation, reduce charge recombination and promote and improve the morphology and crystallinity of a thin film, so that the performance of the device is improved. The siloxane additive can be subjected to intermolecular interaction, the morphology is regulated and controlled, and the stability of the device can be effectively improved; the silica group has low surface energy and hydrophobic property, and is beneficial to large-area processing in air. # imgabs0 #

Description

Technical Field

[0001] The present invention belongs to the technical field of organic photoelectric devices, and in particular relates to a solar cell additive and a preparation method and application thereof. Background Art

[0002] Organic solar cells, with their diverse material range, solution processing capabilities, thinness, flexibility, and ability to produce semi-transparent devices, have shown great potential for development in a variety of fields, including architectural and automotive glass, wearable devices, aerospace, and small electronic devices. With the development of new materials, innovations in device structures, and continuous improvements in device processes, organic solar cells have achieved continuous breakthroughs in efficiency in recent years, demonstrating a bright future. Currently, in order to promote the commercialization of efficiency results from laboratory research on organic solar cells, further improvements in the performance and stability of organic solar devices are needed. The morphology and structure of the active layer have a significant impact on the performance and stability of organic solar cells.

[0003] To ensure efficient photoelectric conversion in organic solar cells, various factors influencing the active layer morphology, such as molecular weight, solubility, and compatibility, must be carefully considered. Ideally, achieving a well-mixed morphology, constructing an interpenetrating network structure between crystals, and maintaining appropriate crystal domain size ensure effective exciton diffusion and charge transport. The donor and acceptor should have uniform molecular orientation, high crystallinity, and structural domain purity to promote exciton dissociation and reduce recombination during charge transport. Therefore, phase separation in the active layer is crucial for efficient charge collection within the device architecture.

[0004] At present, the most common strategies for optimizing the phase separation morphology of the active layer include thermal annealing, solvent vapor annealing and the use of additives. Compared with thermal annealing and solvent vapor annealing, the use of additives is a simpler and more efficient way to optimize the morphology. The additives disclosed and published in the prior art mainly include removal-type additives and residual-type additives. Removal-type additives usually have the characteristics of low boiling point and good volatility, but the humidity needs to be strictly controlled during the device processing, and there will also be poor solubility, which affects the photoelectric conversion efficiency of the device, and may interact with photosensitive materials, shortening the service life of the device. In addition, most of the removal-type additives reported so far will have a negative impact on the environment due to their toxicity, especially in the production, use and processing of future commercial batteries, releasing harmful substances. Residual-type additives have the advantages of high boiling point, low volatility, and the ability to prolong the film drying time, thereby effectively regulating phase separation and molecular orientation. However, they will remain in the active layer film after the device is processed, affecting the stability of the device.

[0005] In view of this, there is an urgent need to develop a safe and effective active layer additive to improve the photoelectric conversion efficiency and stability of organic solar cell devices. Summary of the Invention

[0006] In order to solve the above problems in the prior art, the present invention aims to provide an application of siloxane in a solar cell additive.

[0007] Another object of the present invention is to provide a solar cell additive.

[0008] Another object of the present invention is to provide use of the solar cell additive in the preparation of solar cells.

[0009] Another object of the present invention is to provide a solar cell.

[0010] In order to achieve the above object, the present invention provides the following technical solutions:

[0011] A use of siloxane in a solar cell additive, wherein the siloxane has the following structural formula:

[0012]

[0013] Wherein, Ar is an aromatic unit, including an electron-rich conjugated unit or an electron-deficient conjugated unit; R is selected from C 1～10 Alkylene, C 1～10 Alkyleneoxy, C 1～10 Alkylenethio, C 1～10 SiO is a siloxy group; n is the number of side chain siloxy groups, n = 1 to 4.

[0014] Specifically, the precursor compound of the Ar electron-rich conjugated unit is one of the following structures:

[0015]

[0016] The precursor compound of the Ar electron-deficient conjugated unit is one of the following structures:

[0017]

[0018] R is one of the following structures:

[0019]

[0020] The SiO group is one of the following structures:

[0021]

[0022] Wherein, the precursor compound of the Ar electron-rich conjugated unit may be substituted by 1 to 4 first substituents, wherein the first substituents are selected from -H, -F, -Cl, -Br, -I, -CH3, -OH, -O-CH3, -CO-O-CH3, -SH, -NH-CH3;

[0023] The precursor compound of the Ar electron-deficient conjugated unit may be substituted with 1 to 5 second substituents, wherein the second substituents are selected from -H, -F, -Cl, -Br, -I, -CH3, -OH, -O-CH3, -CO-O-CH3, -SH, and -NH-CH3;

[0024] n1=1~10;n2=1~10.

[0025] Specifically, the precursor compound of the Ar electron-rich conjugated unit is thiophene, and thiophene may be substituted with 1 to 4 first substituents, wherein the first substituents are selected from -Cl, -Br, and -I;

[0026] The precursor compound of the Ar electron-deficient conjugated unit is quinoxaline, which may be substituted by 1 to 5 second substituents, wherein the second substituents are selected from -F, -Br, -CH3, -OH, etc.

[0027] Preferably, the precursor compound of the Ar electron-rich conjugated unit is thiophene, which may be substituted by two first substituents selected from -Cl, -Br, and -I; the precursor compound of the Ar electron-deficient conjugated unit is quinoxaline, which is substituted by five second substituents selected from -F, -Br, and -CH3.

[0028] Specifically, the R is selected from C 1～10 Alkylene, C 1～10 of alkyleneoxy.

[0029] Preferably, R is hexamethylene or hexamethyleneoxy.

[0030] Preferably, the siloxy-based precursor compound is 1,1,1,3,5,5,5-heptamethyltrisiloxane.

[0031] A solar cell additive, comprising: a siloxane solution; the siloxane has the following structural formula:

[0032]

[0033] Wherein, Ar is an aromatic unit, including an electron-rich conjugated unit or an electron-deficient conjugated unit; R is selected from C 1～10 Alkylene, C 1～10 Alkyleneoxy, C 1～10 Alkylenethio, C 1～10ester group; n is the number of side chain silicon oxygen, n = 1 ~ 4.

[0034] Specifically, the precursor compound of the Ar electron-rich conjugated unit is one of the following structures:

[0035]

[0036] The Ar electron-deficient conjugated unit is one of the following structures:

[0037]

[0038] R is one of the following structures:

[0039]

[0040] The SiO group is one of the following structures:

[0041]

[0042] Wherein, the precursor compound of the Ar electron-rich conjugated unit may be substituted by 1 to 4 first substituents, wherein the first substituents are selected from -H, -F, -Cl, -Br, -I, -CH3, -OH, -O-CH3, -CO-O-CH3, -SH, -NH-CH3;

[0043] The precursor compound of the Ar electron-deficient conjugated unit may be substituted with 1 to 5 second substituents, wherein the second substituents are selected from -H, -F, -Cl, -Br, -I, -CH3, -OH, -O-CH3, -CO-O-CH3, -SH, and -NH-CH3;

[0044] n1=1~10;n2=1~10.

[0045] Specifically, the concentration of the siloxane solution is 0.2-2.0 mg / L.

[0046] Specifically, the R group is formed by connecting an alkyl chain containing an unsaturated olefin to an aromatic unit through a nucleophilic reaction to obtain an intermediate; the nucleophilic reaction is carried out under an inert atmosphere.

[0047] More specifically, the siloxy group is formed by reacting the Si-H bond in the siloxy compound with the olefin in the aromatic conjugated unit using a Karstedt catalyst to connect the siloxy group to the intermediate; the addition reaction is carried out under an inert atmosphere and in the dark.

[0048] The present invention also protects the use of the above solar cell additive in the preparation of solar cells.

[0049] A solar cell comprises the above solar cell additive.

[0050] Specifically, the solar cell includes an electrode, an interface layer, and an active layer, and the active layer includes the above-mentioned solar cell additive.

[0051] More specifically, the active layer is composed of semiconductor material.

[0052] More specifically, the active layer includes a donor, an acceptor, and a solar cell additive.

[0053] More specifically, the donor is PM6 or D18, and the acceptor is one of L8-BO, Y6 or BTP-eC9.

[0054] More specifically, the thickness of the active layer is 100-120 nm.

[0055] More specifically, the active layer is prepared by spin coating or printing.

[0056] More specifically, the active layer is prepared by spin coating at a rotation speed of 2000-3000 rpm.

[0057] Compared with the prior art, the present invention has the following beneficial effects:

[0058] The present invention provides a siloxane solar cell additive. The siloxane additive can be used in the active layer of an organic semiconductor device. The additive content is moderate, and the additive can effectively promote exciton dissociation and transport, reduce charge recombination, and promote the improvement of film morphology and crystallinity, thereby improving device performance. In addition, the provided siloxane additive can undergo intermolecular interactions, regulate morphology, and effectively improve device stability. The siloxane group has low surface energy and hydrophobic properties, which is conducive to large-area processing in air. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 1. The hydrogen spectrum and carbon spectrum of Th-SiO in Example 1.

[0060] Figure 2 These are the hydrogen and carbon nuclear magnetic spectra of Me-Qx-SiO in Example 2.

[0061] Figure 3 The following are the hydrogen and carbon nuclear magnetic spectra of Cl-Th-SiO in Example 4.

[0062] Figure 4 The following are the H-NMR and C-NMR spectra of Br-Th-SiO in Example 5.

[0063] Figure 5 These are the H-NMR and C-NMR spectra of I-Th-SiO in Example 6.

[0064] Figure 6 JV curves of organic solar cell devices based on PM6:L8-BO system in Examples 7, 8 and Comparative Example 1.

[0065] Figure 7 JV curves of organic solar cell devices based on PM6:Y6 system in Examples 7, 8 and Comparative Example 1.

[0066] Figure 8 JV curves of organic solar cell devices based on PM6:BTP-eC9 system in Examples 7, 8 and Comparative Example 1.

[0067] Figure 9 JV curves of organic solar cell devices based on the D18:L8-BO system in Examples 7 and 8 and Comparative Example 1.

[0068] Figure 10 This is the JV curve of the organic solar cell device based on the PM6:L8-BO system in Example 9.

[0069] Figure 11 This is a stability curve diagram of the organic solar cell device based on the PM6:L8-BO system in Examples 7 and 8 and Comparative Example 1 under xenon lamp light.

[0070] Figure 12 Graph showing the stability of the organic solar cells based on the PM6:L8-BO system in Examples 7 and 8 and Comparative Example 1 when heated at 80°C. DETAILED DESCRIPTION

[0071] The present invention is further described below with reference to the examples. These examples are intended to illustrate the present invention only and are not intended to limit the scope of the present invention. Experimental methods in the following examples where specific conditions are not specified are generally performed in accordance with conventional conditions in the art or the conditions recommended by the manufacturer; the raw materials and reagents used, unless otherwise specified, are all commercially available from conventional markets. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention fall within the scope of protection claimed in the present invention.

[0072] Example 1

[0073] This embodiment provides a siloxane solar additive named Th-SiO, and its synthesis route is as follows:

[0074]

[0075] Synthesis route of compound 2:

[0076] To a dry, two-necked round-bottom flask purged with argon, magnesium (1.58 g, 65 mmol), a small amount of iodine granules, and 50 mL of ultra-dry tetrahydrofuran were added sequentially. After stirring for 2 minutes, 6-bromohexene (8.15 g, 50 mmol) was slowly added dropwise. The solution gradually turned from red to transparent. After the addition was complete, the mixture was heated under reflux at 60°C for 2 hours. This yielded a Grignard reagent solution, which was used in the next reaction. To another dry, two-necked round-bottom flask purged with argon, 3-bromothiophene (7.34 g, 45 mmol), 1,3-bis(diphenylphosphinopropane)nickel dichloride (0.81 g, 1.5 mmol), and 50 mL of ultra-dry tetrahydrofuran were added sequentially. The reaction solution was slowly added dropwise to the round-bottom flask at 0°C. After the addition was complete, the mixture was heated to 60°C and refluxed for 10 hours. The reaction solution was then cooled to room temperature, quenched with distilled water, extracted three times with dichloromethane, washed three times with saturated sodium chloride solution, dried over anhydrous magnesium sulfate, concentrated by rotary evaporation, and filtered through a petroleum ether column to obtain 6.0 g of a colorless transparent liquid with a yield of 80.1%. 1 H NMR (500MHz, CDCl3) δ (ppm): 7.25-7.23 (m, 1H), 6.94-6.92 (d, 2H), 5.86-5.76 (m, 1H), 5.02 -4.93(q,2H),2.65-2.62(m,2H),2.11-2.05(q,2H),1.68-1.60(m,2H),1.48-1.40(m,2H).

[0077] Synthesis route of additive compound Th-SiO:

[0078] In a double-necked round-bottom flask purged with argon, ultra-dry tetrahydrofuran (50 mL), compound 2 (6 g, 36 mmol), and 1,1,1,3,5,5,5-heptamethyltrisiloxane (16 g, 72 mmol) were added sequentially and heated at 50°C with stirring to dissolve. After 30 minutes, one drop of Karstedt's catalyst was quickly added. The mixture was allowed to react in the dark for 12 hours. After completion of the reaction, the mixture was concentrated under reduced pressure and purified by silica gel column chromatography using a mixture of dichloromethane and petroleum ether (1:40). The final product was 11.67 g of a colorless, transparent liquid with a yield of 83.3%. 1 H NMR (500MHz, CDCl3) δ (ppm): 7.14-7.12 (m, 1H), 6.85-6.82 (t, 2H), 2.55-2.51 (t, 2H),1.54-1.51(t,2H),1.44-1.17(m,8H),0.38-0.35(t,2H),0.02-0.01(d,21H). 13C NMR (100MHz, CDCl3) δ (ppm): 143.21, 128.33, 125.15, 119.92, 33.26, 30.77, 30.55, 29.29, 23.28, 2.07, 1.86.

[0079] Example 2

[0080] This embodiment provides a siloxane solar additive named Me-Qx-SiO, and its synthesis route is as follows:

[0081]

[0082] Synthesis route of compound 4:

[0083] Compound 3 (3.02 g, 10 mmol), pyruvic acid (0.88 g, 10 mmol), and acetic acid (100 mL) were added sequentially to a 500 mL single-necked round-bottom flask, heated and stirred at 40°C for 30 minutes, and then returned to room temperature and stirred for 4 hours. After the reaction was completed, the solution was poured into 2 L of pure water. The precipitate was collected by suction filtration and dried to obtain 2.02 g of the crude product as a white solid with a yield of 57%. No further purification was required.

[0084] Synthesis route of compound 5:

[0085] Under argon, compound 4 (1.06 g, 3 mmol), triphenylphosphine (0.87 g, 3.33 mmol), and anhydrous tetrahydrofuran (40 mL) were added sequentially to a 100 mL double-necked round-bottom flask. 5-Hexen-1-ol (0.31 g, 3.1 mmol) and diisopropyl azodicarboxylate (0.91 g, 4.5 mmol) were added to the mixture at 0°C. After the addition of diisopropyl azodicarboxylate, the reaction solution turned transparent orange and was then heated under reflux for 18 hours. After the reaction was complete, the mixture was cooled to room temperature, quenched with distilled water, and extracted with dichloromethane. The crude product was purified by silica gel column chromatography using a solvent (dichloromethane:petroleum ether = 1:5) as eluent. 1.18 g of a colorless oil was obtained, with a yield of 90%. 1 H NMR (500MHz, CDCl3) δ (ppm): 5.88 (m, 1H), 4.57 (t, 2H), 5.12-4.98 (m, 2H), 2.70 (s, 3H), 2.18 (m, 2H), 1.92 (m, 2H), 1.62 (m, 2H).

[0086] Synthesis route of additive compound Me-Qx-SiO:

[0087] To a double-necked round-bottom flask purged with argon, ultra-dry tetrahydrofuran (30 mL), compound 5 (1 g, 2.3 mmol), and 1,1,1,3,5,5,5-heptamethyltrisiloxane (1.11 g, 5 mmol) were added sequentially and heated at 50°C with stirring to dissolve. After 30 minutes, one drop of Karstedt's catalyst was quickly added. The mixture was allowed to react in the dark for 12 hours. After completion of the reaction, the mixture was concentrated under reduced pressure and purified by silica gel column chromatography using a mixture of dichloromethane and petroleum ether (1:20). The final product was obtained as a colorless, transparent oil (1.33 g) with an 88% yield. 1 H NMR (500MHz, CDCl3) δ (ppm): 4.57 (d, 2H), 2.70 (s, 3H), 1.89 (m, 2H), 1.55-1.37 (m, 6H), 0.48 (t, 2H), 0.09 (m, 18H), 0.01 (m, 3H). 13 C NMR (100MHz, CDCl3) δ (ppm): 157.41, 150.92, 150.75, 150.08, 149.19, 149.02, 148.41, 148.23, 146.70, 146.53, 135.26,132.65,109.11,108.92,107.20,107.02,67.97,32.99,28.64,25.97,23.18,20.22,17.67,2.00,-0.11.

[0088] Example 3

[0089] This embodiment provides a siloxane solar additive named Th-2SiO, and its synthesis route is as follows:

[0090]

[0091] Synthesis route of compound 7:

[0092] To a dry, two-necked round-bottom flask purged with argon, magnesium (2.92 g, 120 mmol), a small amount of iodine granules, and 50 mL of ultra-dry tetrahydrofuran were added sequentially. After heating to boiling, a few drops of 6-bromo-1-hexene were added dropwise to initiate the reaction until the solvent turned transparent. 6-bromo-1-hexene (16.31 g, 100 mmol) was then slowly added dropwise. The reaction was successful when the solution turned gray-green. Heating was maintained at reflux for 3 hours, followed by cooling to room temperature. The solution was then slowly added dropwise to a 50 mL mixture (tetrahydrofuran) containing 3,4-dibromothiophene (6.05 g, 25 mmol) and bis(1,3-diphenylphosphino)propylnickel dichloride [Ni(dppp)Cl2] (542.04 mg), maintaining the mixture at -10°C. The mixture was then allowed to warm to room temperature and the reaction continued for 12 hours. The organic phase was extracted three times with dichloromethane, and the solvent was evaporated using a rotary evaporator to yield a reddish-brown crude product. After rapid column chromatography (petroleum ether), vacuum fractionation was performed to obtain a light yellow liquid product, 2 g of 3,4-di(hex-5-en-1-yl)thiophene, with a yield of 32%. 1 H NMR (500MHz, CDCl3) δ (ppm): 6.89 (s, 1H), 5.87-5.76 (m, 1H), 5.04-4.91 (m, 2H), 2. 54-2.45(m,2H),2.15-1.99(m,2H),1.71-1.56(m,2H),1.48(dd,J=8.3,6.7Hz,2H).

[0093] Synthesis route of additive compound Th-2SiO:

[0094] To a double-necked round-bottom flask purged with argon, ultra-dry tetrahydrofuran (100 mL), compound 7 (2 g, 8.05 mmol), and 1,1,1,3,5,5,5-heptamethyltrisiloxane (7.165 g, 32.2 mmol) were added sequentially and heated at 50°C with stirring to dissolve. After 30 minutes, one drop of Karstedt's catalyst was quickly added. The reaction was allowed to proceed for 12 hours in the dark, and the organic solvent was removed by rotary evaporation. The product was purified by vacuum fractionation and column chromatography (eluent: petroleum ether) to afford a yellow, viscous oil (2.12 g, 38%). 1 HNMR (500MHz, CDCl3) δ (ppm): 6.89 (s, 1H), 2.53-2.46 (m, 2H), 1.64-1.59 (m, 2H), 1.4-1.32 (m, 7H), 0.46 (dd, J = 9.2, 6.2Hz, 2H), 0.09 (d, J = 1.1Hz, 22H).

[0095] Example 4

[0096] This embodiment provides a siloxane solar additive named Cl-Th-SiO, and its synthesis route is as follows:

[0097]

[0098] Under argon, Th-SiO (2.57 mmol, 1 g) was dissolved in 15 mL of chloroform and stirred at 0°C for 10 min. N-chlorosuccinimide (7.7 mmol, 1.03 g) was then added portionwise. The mixture was slowly allowed to return to room temperature and allowed to react in the dark for 24 h. The reaction solution was poured into a large amount of saturated sodium carbonate solution, extracted with dichloromethane, dried over anhydrous magnesium sulfate, concentrated by rotary evaporation, and filtered through a column chromatography column with pure petroleum ether to obtain a colorless, transparent liquid (0.87 g, 74%). 1 H NMR (500MHz, CDCl3) δ (ppm): 6.63 (s, 1H), 2.51-2.48 (m, 2H), 1.55-1.50 (m, 2H), 1.33-1.29 (m, 6H), 0.47-0.43 (t, 2H), 0.1-0.09 (d, 21H). 13 C NMR (100MHz, CDCl3) δ (ppm): 139.41, 127.08, 121.54, 33.03, 29.52, 28.96, 28.19, 23.12, 17.73, 2.02, 1.82, 0.12.

[0099] Example 5

[0100] This embodiment provides a siloxane solar additive named Br-Th-SiO, and its synthesis route is as follows:

[0101]

[0102] Under argon, Th-SiO (2.57 mmol, 1 g) was dissolved in 15 mL of chloroform and stirred at 0°C for 10 min. N-bromosuccinimide (7.7 mmol, 1.37 g) was then added portionwise. The mixture was allowed to slowly return to room temperature and allowed to react in the dark for 12 h. The reaction solution was poured into a large amount of saturated sodium carbonate solution, extracted with dichloromethane, dried over anhydrous magnesium sulfate, concentrated by rotary evaporation, and filtered through a column chromatography column with pure petroleum ether to obtain a colorless, transparent liquid (0.99 g, 71%). 1 H NMR (500MHz, CDCl3) δ (ppm): 6.77-6.75 (t, 1H), 2.52-2.48 (m, 2H), 1.52-1.51 (m, 2H), 1.33-1.29 (m, 6H), 0.48-0.43 (m, 2H), 0.1-0.05 (d, 21H). 13CNMR (100MHz, CDCl3) δ (ppm): 142.82, 130.79, 110..12, 107.75, 32.72, 29.34, 28.65, 26.76, 22.81 17.42, 1.71, 1.50..

[0103] Example 6

[0104] This embodiment provides a siloxane solar additive named I-Th-SiO, and its synthesis route is as follows:

[0105]

[0106] Under argon, Th-SiO (2.57 mmol, 1 g) was dissolved in 15 mL of chloroform and stirred at 0°C for 10 min. N-iodosuccinimide (7.7 mmol, 1.73 g) was then added portionwise. The mixture was allowed to slowly return to room temperature and allowed to react in the dark for 12 h. The reaction solution was poured into a large amount of saturated sodium thiosulfate solution, extracted with dichloromethane, dried over anhydrous magnesium sulfate, concentrated by rotary evaporation, and filtered through a column chromatography column with pure petroleum ether to yield a light yellow, transparent liquid (1.20 g, 73%). 1 H NMR (500MHz, CDCl3) δ (ppm): 6.89 (s, 1H), 2.52-2.49 (m, 2H), 1.54-1.50 (m, 2H), 1.33-1.30 (m, 6H), 0.47-0.44 (m, 2H), 0.1-0.09 (d, 21H). 13 CNMR (100MHz, CDCl3) δ (ppm): 149.68, 137.95, 75.90, 33.07, 32.10, 30.04, 29.00, 23.13, 17.74 2.05, 1.81, 0.10.

[0107] Example 7

[0108] The Th-SiO prepared in Example 1 was used as an active layer additive to prepare an organic solar cell device and its performance was tested.

[0109] The device structure of the organic solar cell is ITO / PEDOT:PSS / active layer (PM6:L8-BO, PM6:Y6, PM6:BTP-eC9, D18:L8-BO) / PDINN / Ag. The device preparation process is as follows:

[0110] (1) Pre-clean the glass bottle containing ITO with ultra-clean water, ethanol, isopropyl alcohol, and acetone, and dry it at 70°C;

[0111] (2) Spin-coat a layer of PEDOT:PSS on a clean ITO glass sheet as the anode interface (thickness 20-30 nm) and anneal at 150 °C for 15 min;

[0112] (3) The photoactive layer was prepared by spin coating a mixed solution containing different donors (PM6:L8-BO, PM6:Y6, PM6:BTP-eC9, D18:L8-BO) with a Th-SiO additive concentration of 0.3-2.0 mg / mL. The preparation details of the different donor-acceptor active layer systems (thickness 100-120 nm) are as follows:

[0113] (3-1) PM6:L8-BO blend film: The PM6:L8-BO blend was prepared in a 1:1.2 mass ratio. 1-Chloro-4-iodobenzene (50% of the total mass of the donor / acceptor) was added and dissolved in chloroform to a concentration of 15 mg / mL. Th-SiO (0.6 mg / mL) was added and stirred at room temperature for 3 hours to ensure complete dissolution. The active layer solution was rotated at 2000–3000 rpm for 40 seconds and annealed at 85°C for 5 minutes to obtain the photoactive layer.

[0114] (3-2) PM6:Y6 blend film: 1-Chloro-4-iodobenzene (50% of the total mass of the donor / acceptor) was added to a PM6:Y6 blend at a mass ratio of 1:1.2. The blend was dissolved in chloroform to a concentration of 15 mg / mL. Th-SiO (0.6 mg / mL) was then added and stirred at room temperature for 3 hours to ensure complete dissolution. The active layer solution was rotated at 2000–3000 rpm for 40 seconds and annealed at 90°C for 5 minutes to obtain a photoactive layer.

[0115] (3-3) PM6:BTP-eC9 blend membrane: 1-Chloro-4-iodobenzene (50% of the total mass of the donor / acceptor) was added to a PM6:BTP-eC9 blend at a mass ratio of 1:1.2. The blend was dissolved in chloroform to a concentration of 15 mg / mL. Th-SiO (0.6 mg / mL) was then added and stirred at 60°C for 2 hours to ensure complete dissolution. The active layer solution was rotated at 2000–3000 rpm for 40 seconds and annealed at 90°C for 5 minutes to obtain a photoactive layer.

[0116] (3-4) D18:L8-BO blend film: D18:L8-BO was prepared in a mass ratio of 1:1.1. 1-Chloro-4-iodobenzene (50% by mass of the total donor / acceptor) was added and dissolved in chloroform to a concentration of 9 mg / mL. Th-SiO (0.6 mg / mL) was added and stirred at 90°C for 1.5 hours to ensure complete dissolution. The active layer solution was rotated at 2000–3000 rpm for 40 seconds and annealed at 100°C for 8 minutes to obtain the photoactive layer.

[0117] (4) PDINN was dissolved in methanol at a concentration of 1 mg / mL and spin-coated to form a cathode interface layer film with a thickness of approximately 5 nm;

[0118] (5) Evaporation of a silver electrode with a thickness of 80 nm.

[0119] A negative bias was applied between the ITO and Ag electrodes, and the cell characteristics were measured under irradiation with 100 mW / cm² AM1.5 simulated sunlight.

[0120] In this example, the photovoltaic performance data of different concentrations of Th-SiO (0.3-2.0 mg / mL) in the PM6:L8-BO active layer system are shown in Table 1. The photovoltaic performance data of Th-SiO with a concentration of 0.6 mg / mL in devices with different active layer systems are shown in Tables 3-6. The relevant JV curves are shown in Tables 3-6. Figure 6-9 shown.

[0121] Example 8

[0122] Using the Me-Qx-SiO of Example 2 as an active layer additive, an organic solar cell device was prepared and its performance was tested. The device structure of the organic solar cell is ITO / PEDOT:PSS / active layer (PM6:L8-BO, PM6:Y6, PM6:BTP-eC9, D18:L8-BO) / PDINN / Ag. The preparation process of the device is carried out according to Example 7. The difference between this embodiment and Example 7 is that the 0.3-2.0 mg / mL Th-SiO additive is replaced with 0.2-0.8 mg / mL Me-Qx-SiO additive. In this example, the photovoltaic performance data of different concentrations of Me-Qx-SiO (0.2-0.8 mg / mL) in the PM6:L8-BO active layer system are shown in Table 2, and the photovoltaic performance data of devices with different active layer systems with a concentration of 0.5 mg / mL are shown in Tables 3-6, and the relevant JV curves are shown in Tables 3-6. Figure 6-9 shown.

[0123] Example 9

[0124] Organic solar cell devices were prepared and their performance tested using Cl-Th-Si, Br-Th-SiO, and I-Th-Si from Examples 4-6 as active layer additives, respectively. The device structure of the organic solar cell was ITO / PEDOT:PSS / PM6:L8-BO / PDINN / Ag. The device preparation process was carried out according to Example 7. The difference between this example and Example 7 was that only the PM6:L8-BO blend film was prepared. The preparation process was as follows: the mass ratio of PM6:L8-BO was 1:1.2, and the total mass concentration of the donor was 15 mg mL -1Dissolve in chloroform and add Cl-Th-Si, Br-Th-SiO, I-Th-Si (concentration of 1 mg mL -1 ), stirred at room temperature for 3 hours to ensure full dissolution. The active layer solution was rotated at 2000-3000 rpm for 40 seconds and annealed at 85°C for 5 minutes to obtain a photoactive layer. The photovoltaic performance data of the PM6:L8-BO system device in this example are shown in Table 7, and the related JV curves are shown in Table 7. Figure 10 shown.

[0125] Comparative Example 1

[0126] The difference between this comparative example and Example 7 is that no Th-SiO additive is added to the active layer, and the rest is the same as Example 7. The photovoltaic performance data of the devices with different active layer systems in Comparative Example 1 are shown in Tables 3-6, and the relevant JV curves are shown in Tables 3-6. Figure 6-9 shown.

[0127] Comparative Example 2

[0128] This comparative example differs from Example 7 in that no Th-SiO additive is added to the active layer, but an equal concentration of 3-hexylthiophene additive is added. PM6:L8-BO is used as the active layer system, and all other conditions are the same as in Example 7. The photovoltaic performance data of the device using the PM6:L8-BO active layer system in Comparative Example 2 is shown in Table 3.

[0129] Comparative Example 3

[0130] This comparative example differs from Example 8 in that the Me-Qx-SiO additive is omitted from the active layer. Instead, an equal concentration of 5,8-dibromo-6,7-difluoro-2-(2-hexyldecyl)oxy-3-methylquinoxaline is added. PM6:L8-BO is used as the active layer system. All other aspects are the same as in Example 8. The photovoltaic performance data for the device using the PM6:L8-BO active layer system in Comparative Example 3 are shown in Table 3.

[0131] Table 1. Summary of photovoltaic performance parameters of different concentrations of Th-SiO additives in PM6:L8-BO active layer system in Example 7

[0132]

[0133] Table 2. Summary of photovoltaic performance parameters of different concentrations of Me-Qx-SiO additives in PM6:L8-BO active layer system in Example 8

[0134]

[0135] Table 3. Summary of photovoltaic performance parameters of Th-SiO and Me-Qx-SiO in PM6:L8-BO active layer systems

[0136]

[0137] Table 4. Summary of photovoltaic performance parameters of Th-SiO and Me-Qx-SiO in PM6:Y6 active layer systems

[0138]

[0139] Table 5. Summary of photovoltaic performance parameters of Th-SiO and Me-Qx-SiO in PM6:BTP-eC9 active layer system

[0140]

[0141] Table 6. Summary of photovoltaic performance parameters of Th-SiO and Me-Qx-SiO in D18:L8-BO active layer systems

[0142]

[0143] Table 7. Summary of photovoltaic performance parameters of different additives in PM6:L8-BO active layer system in Example 9

[0144]

[0145] As shown in Tables 1-7, the photovoltaic performance of organic solar cells prepared with siloxane additives Th-SiO, Me-Qx-SiO, Cl-Th-SiO, Br-Th-SiO and I-Th-SiO is significantly improved.

[0146] Light stability and thermal stability testing

[0147] The light stability test is to place the encapsulated device in a solar light simulator containing ultraviolet light (light intensity: 100mwcm -2 The device temperature is 55°C and the test is carried out under continuous light conditions; the thermal stability test is to place the encapsulated device in the dark on a hot table at 80°C and continuously heat it for testing.

[0148] The organic solar cell devices based on the PM6:L8-BO active layer system in Examples 7 and 8 and Comparative Example 1 were subjected to light stability and thermal stability tests. The light stability test results are shown in FIG. Figure 11 The thermal stability test results are shown in Figure 12 shown.

[0149] Depend on Figure 11 and Figure 12It can be seen that the stability of organic solar cell devices prepared with the siloxane additive Th-SiO or Me-Qx-SiO is significantly improved. In particular, in the light stability test, the stability of the organic solar cell device prepared with the siloxane additive Me-Qx-SiO is better than that of the solar cell device prepared with Th-SiO; in the heating stability test, the stability of the organic solar cell device prepared with the siloxane additive Th-SiO is better than that of the solar cell device prepared with Me-Qx-SiO.

[0150] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. An application of siloxane in a solar cell additive, characterized in that: The siloxane has the following structural formula: Wherein, Ar is an aromatic unit, including an electron-rich conjugated unit or an electron-deficient conjugated unit; R is selected from C 1～10 Alkylene, C 1～10 Alkyleneoxy, C 1～10 Alkylenethio, C 1～10 ester group; SiO is the siloxy group; n is the number of side chain siloxy groups, n = 1 to 4.

2. The application according to claim 1, characterized in that: The precursor compound of the Ar electron-rich conjugated unit is one of the following structures: The precursor compound of the Ar electron-deficient conjugated unit is one of the following structures: R is one of the following structures: The SiO group is one of the following structures: Wherein, the precursor compound of the Ar electron-rich conjugated unit may be substituted by 1 to 4 first substituents, wherein the first substituents are selected from -H, -F, -Cl, -Br, -I, -CH3, -OH, -O-CH3, -CO-O-CH3, -SH, -NH-CH3; The precursor compound of the Ar electron-deficient conjugated unit may be substituted by 1 to 5 second substituents, wherein the second substituents are selected from -H, -F, -Cl, -Br, -I, -CH3, -OH, -O-CH3, -CO-O-CH3, -SH, -NH-CH3; n1=1~10; n2=1~10.

3. The application according to claim 1, characterized in that: The precursor compound of the Ar electron-rich conjugated unit is thiophene, and thiophene may be substituted by 1 to 4 first substituents, and the first substituents are selected from -H, -F, -Cl, -Br, -I, -CH3, -OH, -O-CH3, -CO-O-CH3, -SH, and -NH-CH3; The precursor compound of the Ar electron-deficient conjugated unit is quinoxaline, which may be substituted by 1 to 5 second substituents, and the second substituents are selected from -H, -F, -Cl, -Br, -I, -CH3, -OH, -O-CH3, -CO-O-CH3, -SH, and -NH-CH3.

4. The use according to claim 1, characterized in that: The R is selected from C 1～10 Alkylene, C 1～10 of alkyleneoxy.

5. The use according to claim 1, characterized in that: The precursor compound of the siloxy group is 1,1,1,3,5,5,5-heptamethyltrisiloxane.

6. A solar cell additive, characterized in that: include: Siloxane solution; The siloxane has the following structural formula: Wherein, Ar is an aromatic unit, including an electron-rich conjugated unit or an electron-deficient conjugated unit; R is selected from C 1～10 Alkylene, C 1～10 Alkyleneoxy, C 1～10 Alkylenethio, C 1～10 ester group; n is the number of side chain silicon oxygen, n = 1 ~ 4.

7. The solar cell additive according to claim 6, characterized in that: The precursor compound of the Ar electron-rich conjugated unit is one of the following structures: The Ar electron-deficient conjugated unit is one of the following structures: R is one of the following structures: The SiO group is one of the following structures: Wherein, the precursor compound of the Ar electron-rich conjugated unit may be substituted by 1 to 4 first substituents, wherein the first substituents are selected from -H, -F, -Cl, -Br, -I, -CH3, -OH, -O-CH3, -CO-O-CH3, -SH, -NH-CH3; The precursor compound of the Ar electron-deficient conjugated unit may be substituted by 1 to 5 second substituents, wherein the second substituents are selected from -H, -F, -Cl, -Br, -I, -CH3, -OH, -O-CH3, -CO-O-CH3, -SH, -NH-CH3; n1=1~10; n2=1~10.

8. The solar cell additive according to claim 6, characterized in that: The concentration of the siloxane solution is 0.2-2.0 mg / L.

9. Use of the solar cell additive according to any one of claims 6 to 8 in the preparation of solar cells.

10. A solar cell, characterized in that: The invention comprises the solar cell additive according to any one of claims 6 to 8.

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