A method for preparing the active layer of an organic solar cell

Abstract

This invention relates to the field of organic solar cell materials, and provides a method for preparing the active layer of an organic solar cell and the active layer of the organic solar cell obtained by this method. The preparation method includes the following steps: S1: dissolving a donor material and an acceptor material in an organic solvent; S2: spin-coating the mixed solution obtained in step S1 onto an electron transport layer; the acceptor material is a non-fused-ring electron acceptor material with the molecular formula A-D-D'-A. The method for preparing the active layer of the organic solar cell according to this invention does not require annealing or the addition of high-boiling-point additives, yet still achieves excellent photoelectric conversion efficiency of the solar cell.

Description

Technical Field

[0001] This invention belongs to the field of organic solar cell materials, and particularly relates to a method for preparing an active layer of an organic solar cell and the active layer of the organic solar cell obtained by the method, a method for preparing an organic solar cell and the organic solar cell obtained by the method, an organic solar cell module and an organic solar cell system. Background Technology

[0002] Bulk heterojunction (BHJ) organic solar cells (OSCs) have attracted significant interest from academia and industry due to their unique technological advantages, including solution-processability, flexibility, lightweight, and semi-transparency. Thanks to the groundbreaking innovation of the fused-ring electron acceptor structure, the photon-to-electron conversion efficiency (PCE) of single-junction and tandem OSCs has exceeded 17%. To further improve the performance and stability of OSCs to meet the fundamental requirements of commercial applications, researchers have successfully developed device fabrication processes (e.g., using additives, thermal annealing, and solvent vapor annealing) to control the morphology of blended thin films of the active layer.

[0003] On the one hand, in receptor molecule design, extending the conjugation length of the fused-ring core of the receptor is one of the important means to obtain high-performance receptors. However, simply extending the conjugation length of the core can easily lead to drawbacks such as increased synthesis difficulty and excessive molecular aggregation. Therefore, current high-efficiency small molecule receptor materials generally suffer from complex molecular structures, high synthesis costs, and great difficulty.

[0004] On the other hand, from the perspective of device fabrication technology, polymer donor materials and small molecule acceptor materials have different crystallization rates. Adding solvent additives can make the two materials have matching crystallization rates in the blend solution, thereby obtaining a thin film morphology that is conducive to charge transport. However, solvent additives are difficult to remove under the subsequent thermal annealing conditions of the active layer, and during long-term storage of the device, these residual solvent additives will damage the morphology of the active layer, resulting in a significant degradation of device performance. For example, patent application CN113563362A discloses an AD-D'-A type asymmetric organic photovoltaic acceptor material. However, this acceptor material is a fused-ring small molecule, and in the process of mixing it with the acceptor to prepare a solar photovoltaic cell, it is necessary to add solvent additives (such as CN) and perform annealing treatment (such as annealing at 100°C and CS2 solvent vapor annealing).

[0005] To obtain stable and efficient organic solar cells, the use of liquid additives with high boiling points should be avoided as much as possible. Although researchers have developed volatile solid additives, such as adding ferrocene or thiophene derivatives to chlorobenzene or chloroform solvents, these solid additives can improve both cell efficiency and stability. However, these methods cannot avoid the drawback that these additives are difficult to remove during the annealing process. Summary of the Invention

[0006] This invention provides a method for preparing the active layer of an organic solar cell, aiming to solve the problems of adding difficult-to-remove solvent additives and requiring annealing in the preparation process of the active layer of organic solar cells in the prior art.

[0007] The present invention is implemented as follows: a method for preparing the active layer of an organic solar cell includes the following steps:

[0008] S1: Dissolve the donor and acceptor materials in an organic solvent;

[0009] S2: Spin-coat the mixed solution obtained in step S1 onto the electron transport layer;

[0010] The acceptor material is a non-fused-ring electron acceptor material with the molecular structural formula AD-D'-A, and the general structural formula of the non-fused-ring electron acceptor material is shown in Formula I.

[0011] ,in:

[0012] R1 is selected from any of the following groups:

[0013] ,

[0014] R2 is -C x H y or -CH(C n H m C x H y x is an integer from 4 to 12, y is an integer from 11 to 23, n is an integer from 2 to 8, and m is an integer from 7 to 15;

[0015] R3 is C 4-10 Alkyl groups;

[0016] R4 is -C a H b -OC a H b , -CH(C c H d C a H bor -OCH(C c H d C a H b a is an integer from 2 to 12, b is an integer from 7 to 23, c is an integer from 1 to 8, and d is an integer from 3 to 15; and

[0017] X is a halogen.

[0018] Furthermore, R2 is a saturated alkyl group, and x is an even number from 4 to 12, and n is an even number from 2 to 8.

[0019] Furthermore, R2 is selected from any of the following groups:

[0020] .

[0021] Furthermore, R4 is a saturated alkyl or saturated alkoxy, and a is an even number from 2 to 12, and c is an even number from 2 to 8.

[0022] Furthermore, R4 is selected from any of the following groups:

[0023] .

[0024] Furthermore, X is either Cl or F.

[0025] Furthermore, the electron transport layer is made of ZnO or SnO.

[0026] Furthermore, the mass ratio of the donor material to the acceptor material is 1:1.

[0027] Furthermore, both steps S1 and S2 are performed under nitrogen protection.

[0028] The present invention also provides an active layer for an organic solar cell, wherein the active layer is obtained by the preparation method of the present invention.

[0029] This invention also provides a method for preparing an organic solar cell, comprising the following steps:

[0030] Si: Cleaning substrate; preferably, the cleaning surface is etched with strips of ITO conductive glass;

[0031] Sii: To prepare an electron transport layer, a mixed solution containing metal oxides is spin-coated onto a substrate obtained in step Si, and then the substrate is annealed;

[0032] Siii: Prepare the active layer according to the preparation method of the present invention;

[0033] Siv: A hole transport layer and a metal electrode are deposited sequentially on the active layer. Preferably, in a 5×10 -4The films were deposited at low pressures below Pa at rates of 0.1 Å / s and 1 Å / s, respectively, with thicknesses of 10 nm and 150 nm. The effective area of ​​the cell is 3.97 mm². 2 .

[0034] In step Si, the transparent conductive glass with striped ITO etched on its surface is cleaned sequentially using glass cleaner, deionized water, acetone, and isopropanol as cleaning agents under ultrasonic conditions, with each ultrasonic treatment lasting 15 minutes. After cleaning, the ITO glass is dried with a nitrogen gun and then placed in a vacuum plasma machine for surface treatment for 2 to 5 minutes, preferably 3 minutes.

[0035] In step Sii, a mixed solution of metal oxides is prepared in a 2-methoxyethanol solution using zinc acetate dihydrate particles and ethanolamine as reactants.

[0036] In step Sii, the spin coating conditions are a rotation speed of 2000 rpm to 5000 rpm for 20 to 50 seconds, preferably 30 seconds. The spin-coated ZnO substrate is then placed on a heating stage at 200 °C for annealing for 1 hour.

[0037] In step Siv, the hole transport layer is MoO3, and its thickness is preferably 10 nm; and the metal electrode is Ag or Al, and its thickness is preferably 150 nm.

[0038] The present invention also provides an organic solar cell, which is obtained by the preparation method according to the present invention.

[0039] The present invention also provides an organic solar cell module comprising an organic solar cell according to the present invention.

[0040] The present invention also provides an organic solar cell system comprising an organic solar cell module according to the present invention.

[0041] Thanks to the non-fused-ring AD-D'-A type acceptor material, the planarization of the molecular framework is promoted through non-covalent bonds, resulting in excellent molecular packing orientation of the acceptor molecules, which is more conducive to charge transport. Therefore, the active layer of the organic solar cell according to the present invention does not require annealing or the addition of high-boiling-point additives, yet still achieves excellent photoelectric conversion efficiency. Attached Figure Description

[0042] Figure 1 This is the UV-Vis absorption spectrum of the electron acceptor material DTP-EHT-4F according to Embodiment 1 of the present invention in solution and thin film states;

[0043] Figure 2This is a schematic diagram of the structure of an organic solar cell according to the present invention;

[0044] Figure 3 The JV curve of the organic solar cell prepared from the non-fused-ring electron acceptor material DTP-EHT-4F of Example 1 is shown.

[0045] Figure 4 The JV curves of organic solar cells with non-fused-ring electron acceptor materials in Comparative Examples 1 to 3 after additive and thermal annealing treatment are shown.

[0046] Figure 5 The JV curves of organic solar cells prepared from non-fused-ring electron acceptor materials in Comparative Examples 4 to 7 after different solvent vapor annealing treatments are shown.

[0047] Figure 6 This is a graph showing the efficiency degradation of an organic solar cell prepared from the non-fused-ring electron acceptor material DTP-EHT-4F according to Embodiment 1 of the present invention after continuous illumination or heating.

[0048] Figure 7 This is a comparison of the JV curves of organic solar cells prepared according to Example 1 and those prepared according to Example 2 using non-fused-ring electron acceptor materials.

[0049] Figure 8 This is a comparison of the JV curves of organic solar cells prepared according to Example 1 and those prepared according to Example 3 using non-fused-ring electron acceptor materials.

[0050] Figure 9 This is a comparison chart of the JV curves of organic solar cells prepared according to Example 1 and according to Example 4 using non-fused-ring electron acceptor materials. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0052] In receptor molecule design, extending the conjugation length of the fused-ring core is a crucial method for obtaining high-performance receptors. However, simply extending the conjugation length can lead to drawbacks such as increased synthetic difficulty and excessive molecular aggregation. This invention employs a non-fused-ring electronic structure, different from traditional fused-ring electron acceptors, by introducing nitrogen-functionalized two-dimensional side chains into the non-fused-ring electron acceptor structure. The preparation method according to this invention eliminates the need for an annealing step while still ensuring efficient charge transport.

[0053] In this invention, the term "non-fused-ring electron acceptor" means an electron acceptor comprising at least one monocyclic unit. In this invention, the thiophene unit is a monocyclic unit, while the dithiophene-pyrrole unit is a polycyclic unit, and the thiophene unit and the dithiophene-pyrrole unit are connected by a single bond to form a conjugated structure.

[0054] The acceptor material is a non-fused-ring electron acceptor material with the molecular formula: AD-D'-A, wherein...

[0055] , , , .

[0056] When R1 is And R2 is a straight-chain alkyl-C x H y or branched alkyl-CH(C) n H m C x H y This effectively ensures the solubility of the acceptor molecules, allowing for a more ideal phase separation morphology when the acceptor molecules are blended with the polymer donor material. Specifically, an ideal phase separation morphology refers to an interpenetrating nanofiber network structure. Under this ideal film morphology, excitons are effectively separated, charge can be transported efficiently, the fill factor (FF) is significantly improved, and the PCE (photoelectric conversion efficiency) is naturally enhanced.

[0057] When R1 includes a cyclic group, it can exert a steric hindrance effect, inhibiting excessive self-aggregation of acceptor molecules. However, steric hindrance and solubility need to be balanced. In this invention, the C5-C10 straight-chain alkyl group R3 can balance steric hindrance and solubility.

[0058] Furthermore, by introducing nitrogen-functionalized two-dimensional side chains into the design of non-fused-ring electron acceptors based on the dithiophene-pyrrole (DTP) unit of compound 1, excessive self-aggregation of acceptor molecules can be effectively suppressed. Unlike carbon-functionalized two-dimensional side chains, the electron-rich nitrogen atoms in DTP can improve the stability of organic semiconductors in the oxidized state, thereby increasing the operating time of optoelectronic devices. Simultaneously, due to the steric hindrance between the two-dimensional side chains and adjacent thiophene groups, a certain dihedral angle is generated between the two-dimensional side chains and the core framework, which can effectively improve the stacking orientation of acceptor molecules, providing more charge transport channels for both lateral and longitudinal transport. Therefore, the battery prepared using the acceptor of this invention exhibits superior photoelectric performance.

[0059] Example 1

[0060] This embodiment provides an organic solar cell fabricated from a non-fused-ring electron acceptor material. For example... Figure 2 As shown, the glass substrate comprises, from bottom to top: a cathode electrode, an electron transport layer, an active layer, a hole transport layer, and an anode electrode.

[0061] The specific fabrication steps for organic solar cells are as follows:

[0062] Si: Cleaning substrate. Preferably, the substrate is a conductive glass comprising strips of indium tin oxide (ITO).

[0063] Specifically, the substrate cleaning steps include: cleaning the transparent conductive glass with striped ITO (cathode) etched on its surface sequentially using glass cleaner, deionized water, acetone, and isopropanol as cleaning agents under ultrasonic conditions, with each ultrasonic step lasting 15 minutes. After the substrate cleaning step, the cleaned ITO glass can be dried with a nitrogen gun and then placed in a vacuum plasma machine for 3 minutes to optimize the surface wettability and work function of the ITO.

[0064] Sii: The electron transport layer is prepared by spin-coating a mixed solution containing a metal oxide onto a substrate obtained in step Si, followed by annealing the substrate. Preferably, the metal oxide is ZnO.

[0065] Specifically, the ZnO electron transport layer is prepared as follows: 1 g of zinc acetate dihydrate particles and 0.28 g of ethanolamine are dissolved in 10 mL of 2-methoxyethanol solution and stirred at room temperature for 5 h. The mixture is then uniformly spin-coated onto an ITO glass surface at 5000 rpm for 30 s. The spin-coated ZnO substrate is then annealed on a heating stage at 200°C for 1 h.

[0066] Siii: The active layer of an organic solar cell is prepared according to the preparation method of the present invention. Specifically, it includes:

[0067] S1: Dissolve the donor and acceptor materials in an organic solvent;

[0068] S2: Spin-coat the mixed solution obtained in step S1 onto the electron transport layer;

[0069] Specifically, the active layer was prepared in a nitrogen-filled glove box. The active layer solution was prepared by: using the donor material PM6 (whose specific structure is as follows)... The donor and acceptor materials were dissolved in chloroform solvent at a total concentration of 15 mg / mL, with a donor-to-acceptor mass ratio of 1:1. The mixture was stirred at room temperature for 12 h to ensure complete dissolution. The mixture was then spin-coated onto a ZnO thin film at 3000 rpm for 30 s. Compared to existing solar cell fabrication methods, the method according to the present invention does not require annealing or the addition of high-boiling-point additives, yet still yields solar cells with excellent photoelectric conversion efficiency, as described in detail below.

[0070] Siv: A hole transport layer and a metal electrode are deposited sequentially on the active layer.

[0071] Specifically, both the hole transport layer MoO3 and the metal electrode Ag were prepared using a vacuum evaporation method, and the preparation process is as follows: [The text abruptly ends here, likely due to an incomplete sentence or a formatting error.] -4 The films were deposited at low pressures below Pa at rates of 0.1 Å / s and 1 Å / s, respectively, with thicknesses of 10 nm and 150 nm. The effective area of ​​the cell is 3.97 mm². 2 .

[0072] In this embodiment, organic solar cells were prepared using the following acceptor materials as raw materials according to the preparation method of the present invention:

[0073] ; ;

[0074] ; .

[0075] The specific synthetic route of the electron acceptor material DTP-EHT-4F is as follows: .

[0076] Furthermore, the specific synthesis steps are as follows:

[0077] Specifically, firstly, under the protection of nitrogen, compound 1 is... (3.0 g, 7.2 mmol) was dissolved in a dry tetrahydrofuran solution (80 mL). Over 10 minutes, n-butyllithium (3.0 mL, 7.2 mmol) was added dropwise to the above solution. After stirring at -78 °C for 1.5 h, N,N-dimethylformamide (DMF) (1.1 g, 14.4 mmol) was added dropwise, and the solution was then warmed to room temperature and stirred for another 1 h. The mixture was poured into ice water (100 mL), neutralized with Na₂CO₃ solution, and extracted with dichloromethane. The organic layer was washed with water and brine and dried over anhydrous MgSO₄. After removing the solvent by rotary evaporation under reduced pressure, the crude product was purified by silica gel column chromatography to give 3.0 g of compound 2. (Yellow solid, yield 93%).

[0078] Then, under nitrogen protection, N-methylpiperazine (858.6 mmL, 7.7 mmol) was dissolved in a dry tetrahydrofuran solution (80 mL). Over 10 minutes, n-butyllithium (3.2 mL, 7.7 mmol) was added dropwise to the solution. After stirring at -78 °C for 30 minutes, compound 2 (3 g, 6.7 mmol) was added, and the mixture was stirred again for 30 minutes. Then, n-butyllithium (3.2 mL, 7.7 mmol) was added dropwise again. After stirring at -20 °C for 2 hours, the temperature was lowered to -78 °C, and tributyltin chloride (2.2 mL, 8.1 mmol) was added dropwise. The solution was then warmed to room temperature and stirred for another 2 hours. The mixture was poured into an aqueous hydrochloric acid solution (50 mL), neutralized with Na₂CO₃ solution, and extracted with ethyl acetate. The organic layer was washed with water and brine and dried over anhydrous MgSO₄. After removing the solvent by rotary evaporation under reduced pressure, compound 3 was obtained. (Viscous liquid) was directly incorporated into the synthesis of compound 5 without further purification.

[0079] Then, under nitrogen protection, compound 3 was... (1.2 g, 1.6 mmol), compound 4 (625.7 mg, 2.0 mmol) of dried toluene (12 mL) was placed in a Schlenk vacuum-sealed flask (50 mL). After freezing with liquid nitrogen, the mixture was purged with argon three times, followed by the addition of tetraphenylphosphine palladium (37.8 mg, 32.7 μmol). The mixture was heated to reflux at 110 °C for 6 hours. After the reaction was completed and cooled to room temperature, the reaction solution was filtered through diatomaceous earth, the organic phase was collected, washed with water, and the solvent was removed by rotary evaporation. The crude product was purified by silica gel column chromatography to give 940 mg of compound 5. (Orange viscous liquid, yield 82%).

[0080] Finally, compound 5 (200 mg, 292 μmol) and compound 6 (fluoroindanedione) (269 mg, 1.2 mmol) were dissolved in a mixture of 1,2-dichloroethane (20 mL) and dry ethanol (4 mL), and β-amino acid (2.6 mg, 29.2 μmol) was added. The mixture was heated under reflux at 55 °C for 12 hours. After the reaction was complete, the reaction solution was extracted with dichloromethane, the organic phase was collected, washed with water, the solvent was removed by rotary evaporation, and the crude product was purified by silica gel column chromatography to give 240 mg of the final product DTP-EHT-4F (dark black solid, 75% yield).

[0081] The synthesis methods of the receptor materials DTP-Th-EHT-4F, DTP-Ph-EHT-4F and DTP-TT-EHT-4F in this embodiment are similar to those of DTP-EHT-4F, except that the specific structure of compound 1 is different.

[0082] Comparative Example

[0083] In Comparative Examples 1 to 7, only the preparation process of the active layer of the solar cell, Siii, is different, while the other steps, Si, Sii, and Siv, remain unchanged.

[0084] The preparation process of the active layer in Comparative Example 1 is as follows: The donor material PM6 and the acceptor material DTP-EHT-4F were dissolved in chloroform solvent, with a total concentration of 15 mg / mL and a donor-to-acceptor mass ratio of 1:1. The mixture was stirred at room temperature for 12 h to ensure complete dissolution. Then, the mixture was spin-coated onto a ZnO film at 3000 rpm for 30 s. Finally, the active layer was annealed at 100℃ for 10 min.

[0085] The preparation process of the active layer in Comparative Example 2 is as follows: The donor material PM6 and the acceptor material DTP-EHT-4F were dissolved in chloroform solvent to a total concentration of 15 mg / mL, with a donor-to-acceptor mass ratio of 1:1. 0.5% (v / v) of DIO (1,8-diiodooctane) was added as an additive. The mixture was stirred at room temperature for 12 h to ensure complete dissolution. Then, the mixture was spin-coated onto a ZnO film at 3000 rpm for 30 s.

[0086] The preparation process of the active layer in Comparative Example 3 is as follows: The donor material PM6 and the acceptor material DTP-EHT-4F were dissolved in chloroform solvent, with a total concentration of 15 mg / mL and a donor-to-acceptor mass ratio of 1:1. 0.5% DIO (by volume) was added as an additive. The mixture was stirred at room temperature for 12 h to ensure complete dissolution. Then, the mixture was spin-coated onto a ZnO film at 3000 rpm for 30 s. Finally, the active layer was annealed at 100 °C for 10 min.

[0087] The preparation process of the active layer in Comparative Example 4 is as follows: The donor material PM6 and the acceptor material DTP-EHT-4F were dissolved in chloroform solvent, with a total concentration of 15 mg / mL and a donor-to-acceptor mass ratio of 1:1. The mixture was stirred at room temperature for 12 h to ensure complete dissolution. Then, the mixture was spin-coated onto a ZnO film at 3000 rpm for 30 s. Finally, the active layer was placed in a 1.5 cm diameter petri dish, and 45 μL of chloroform solvent was rapidly added along the edge of the dish. The dish was then capped and annealed with solvent vapor for 15 s.

[0088] Similar to Comparative Example 4, the only difference in Comparative Example 5 is that the solution in the solution vapor annealing step is 45 μL of dichloromethane solvent; the only difference in Comparative Example 6 is that the solution in the solution vapor annealing step is 45 μL of carbon disulfide solvent; and the only difference in Comparative Example 7 is that the solution in the solution vapor annealing step is 45 μL of tetrahydrofuran solvent.

[0089] Using AM1.5G spectral distribution and illuminance of 100 mw / cm², 2 Using an Oriel 300 W solar simulator as the light source, the photoelectric performance of organic solar cells prepared from the four different non-fused-ring electron acceptor materials and the organic solar cells obtained in Comparative Examples 1 to 7 were tested. The JV curves were obtained through measurements using a Keithly 2400 digital source meter. Figure 4 and Figure 5 As shown in the figure, the photoelectric performance test parameters are obtained, as shown in Table 1.

[0090] Table 1: Comparison of photoelectric performance test parameters of the four acceptor materials in Example 1 and the solar cells of Comparative Examples 1 to 7

[0091]

[0092] As shown in Table 1, compared with the various device optimization strategies used in the comparative examples, including organic solar cells prepared by adding additives, thermal annealing and solvent vapor annealing, the device obtained by the preparation method according to the present invention still achieved a photoelectric conversion efficiency of 7.6-8.6% without adding any additives or annealing.

[0093] To further observe the stability of devices directly fabricated based on this acceptor material (as-cast) under conditions without any additives or annealing, we placed devices fabricated from DTP-EHT-4F in a glove box and tested their efficiency after 200 hours of continuous illumination or 200 hours of continuous heating (at 85°C). Figure 6 As shown, after continuous illumination or heating in a glove box for 200 h, the directly prepared as-cast device still maintained more than 90% of its initial efficiency, further demonstrating that this acceptor material has excellent photovoltaic performance and is expected to be used in semi-transparent and indoor photovoltaic devices.

[0094] Example 2

[0095] This comparative example presents a non-fused-ring electron acceptor material and a ternary organic solar cell constructed therefrom. A "ternary organic solar cell" refers to an organic solar cell that includes a third donor material or a third acceptor material in addition to the acceptor and donor. The fabrication process of this ternary organic solar cell differs from that of Example 1 only in the preparation process of the active layer; the remaining steps remain the same.

[0096] In this embodiment, the preparation process of the active layer is as follows: Donor material PM6, second donor material D18, and acceptor material DTP-EHT-4F are dissolved in chloroform solvent at a mass ratio of 0.9:0.1:1, with a total concentration of 15 mg / mL. The mixture is stirred at room temperature for 12 h to ensure complete dissolution. Then, the mixture is spin-coated onto a ZnO film at 3000 rpm for 30 s.

[0097] like Figure 7 As shown, compared to the corresponding binary organic solar cells, the introduction of D18 has little impact on the open-circuit voltage, but significantly improves the short-circuit current density and fill factor, thus achieving higher photoelectric conversion efficiency. Compared to the organic solar cell prepared using the non-fused-ring electron acceptor material according to Example 1, the organic solar cell prepared using the ternary strategy according to this example exhibits a superior JV curve.

[0098] Example 3

[0099] Similar to Example 2, this example provides a ring electron acceptor material and a ternary organic solar cell constructed therefrom. The preparation process of the active layer is as follows: donor material PM6, acceptor material DTP-EHT-4F, and a second acceptor material PC are... 61 BM was dissolved in chloroform solvent at a mass ratio of 1:0.9:0.1. The remaining conditions and procedures were the same as those in Comparative Example 6.

[0100] like Figure 8 As shown, compared to corresponding binary organic solar cells, PC 61 The introduction of BM significantly improved the open-circuit voltage, which may be due to PC. 61 BM has a higher LUMO energy level than the acceptor material DTP-EHT-4F. Furthermore, PC... 61 The spherical structure of BM endows the ternary blend with better charge transport performance, resulting in a significant improvement in short-circuit current density and fill factor. Consequently, the ternary organic solar cell achieves a higher photoelectric conversion efficiency. Compared with the organic solar cell prepared using the non-fused-ring electron acceptor material according to Example 1, the organic solar cell prepared using the ternary strategy according to this example exhibits a superior JV curve.

[0101] Example 4

[0102] Similar to Example 2, this example provides a ring electron acceptor material and a ternary organic solar cell constructed therefrom. The preparation process of the active layer is as follows: donor material PM6, acceptor material DTP-EHT-4F, and second acceptor material Y6 are dissolved in chloroform solvent at a mass ratio of 1:0.9:0.1. The remaining conditions and steps are the same as in Comparative Example 6.

[0103] like Figure 9 As shown, the initial absorption edge of the second acceptor material Y6 can reach approximately 935 nm, exhibiting a narrower optical bandgap compared to the acceptor material DTP-EHT-4F. Its introduction allows for a wider absorption range in the active layer, resulting in a larger short-circuit current density. Consequently, the corresponding ternary organic solar cell achieves higher photoelectric conversion efficiency. Compared to the organic solar cell prepared using the non-fused-ring electron acceptor material according to Example 1, the organic solar cell prepared using the ternary strategy according to this example exhibits a superior JV curve.

[0104] Table 2 Comparison of photoelectric performance test parameters of solar cells in Examples 1 to 4

[0105]

[0106] As shown in Table 2, adding a third donor or acceptor material during the preparation of the active layer, i.e., adopting a ternary strategy, is another effective way to improve the efficiency and stability of organic photovoltaic cells. The intermolecular interactions between the additional component and the donor or acceptor material in the main system can effectively improve the morphology of the active layer and form a network channel that is conducive to charge transport.

[0107] In summary, thanks to the non-fused-ring AD-D'-A type acceptor material, the planarization of the molecular framework is promoted through non-covalent bonds, resulting in excellent molecular packing orientation of the acceptor molecules, which is more conducive to charge transport. Therefore, the active layer of the organic solar cell according to the present invention does not require annealing or the addition of high-boiling-point additives, yet still achieves excellent photoelectric conversion efficiency.

[0108] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing the active layer of an organic solar cell, characterized in that, Includes the following steps: S1: Dissolve the donor and acceptor materials in an organic solvent; S2: Spin-coat the mixed solution obtained in step S1 onto the electron transport layer; The receptor material is a non-fused-ring electron acceptor material with the molecular structural formula: AD-D'-A. Furthermore, the general structural formula of the non-fused-ring electron acceptor material is shown in Formula I. ,in: R1 is selected from any of the following groups: ， R2 is -C x H y or -CH(C n H m C x H y x is an integer from 4 to 12, y is an integer from 11 to 23, n is an integer from 2 to 8, and m is an integer from 7 to 15; R3 is C 4-10 Alkyl groups; R4 is -C a H b -OC a H b , -CH(C c H d C a H b or -OCH(C c H d C a H b a is an integer from 2 to 12, b is an integer from 7 to 23, c is an integer from 1 to 8, and d is an integer from 3 to 15; and X is a halogen; R4 is selected from any one of the following groups: 。 2. The preparation method according to claim 1, characterized in that, R2 is a saturated alkyl group, and x is an even number from 4 to 12, and n is an even number from 2 to 8.

3. The preparation method according to claim 2, characterized in that, R2 is selected from any of the following groups: 。 4. The preparation method according to claim 1, characterized in that, R4 is a saturated alkyl or saturated alkoxy group, and a is an even number from 2 to 12, and c is an even number from 2 to 8.

5. The preparation method according to claim 1, characterized in that, X is either Cl or F.

6. The preparation method according to claim 1, characterized in that, The electron transport layer is made of ZnO or SnO.

7. The preparation method according to any one of claims 1 to 6, characterized in that, The mass ratio of the donor material to the acceptor material is 0.5~1:0.5~1.

8. The preparation method according to any one of claims 1 to 6, characterized in that, Both steps S1 and S2 are performed under nitrogen protection.

9. An active layer of an organic solar cell, characterized in that, The active layer is obtained by the preparation method according to any one of claims 1 to 8.

10. A method for preparing an organic solar cell, characterized in that, Includes the following steps: Si: Cleaning substrate; Sii: The preparation of an electron transport layer includes spin-coating a mixed solution containing metal oxides onto a substrate obtained in step Si, and then annealing the substrate; Siii: The active layer is prepared by the preparation method according to any one of claims 1 to 9; Siv: A hole transport layer and a metal electrode are deposited sequentially on the active layer.

11. The preparation method according to claim 10, characterized in that, In step Si, the substrate is a conductive glass comprising indium tin oxide.

12. The preparation method according to claim 10, characterized in that, In step Si, cleaning the substrate includes: cleaning the transparent conductive glass with striped ITO etched on its surface sequentially using glass cleaner, deionized water, acetone, and isopropanol as cleaning agents under ultrasonic conditions.

13. The preparation method according to claim 10, characterized in that, In step Si, after cleaning the substrate, the ITO glass is dried with a nitrogen gun and then placed in a vacuum plasma machine for surface treatment for 2 to 5 minutes.

14. The preparation method according to claim 10, characterized in that, In step Sii, the mixed solution containing the metal oxide is prepared in a 2-methoxyethanol solution using zinc acetate dihydrate particles and ethanolamine as reactants.

15. The preparation method according to claim 10, characterized in that, In step Siv, the hole transport layer is made of MoO3.

16. The preparation method according to claim 10, characterized in that, In step Siv, the metal electrode is made of Ag or Al.

17. An organic solar cell, characterized in that, It is obtained by the preparation method according to any one of claims 10 to 16.

18. An organic solar cell module, characterized in that, It includes the organic solar cell as described in claim 17.

19. An organic solar cell system, characterized in that, It includes the organic solar cell module as described in claim 18.

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