An organic solar cell and a method for preparing the same

Abstract

The present invention provides an organic solar cell and a preparation method thereof, belonging to the technical field of solar cells. In the organic solar cell of the present invention, an anode, an anode interface layer, an active layer, a cathode interface layer and a cathode are sequentially stacked; the photoactive material used for preparing the active layer includes a donor material and an acceptor material, the donor material includes PTB7, PBDB-T or PM6, and the acceptor material includes PC 71 BM, ITIC or Y6; the cathode interface material used for preparing the cathode interface layer includes a quinacridone derivative or a nitrogen-doped quinacridone derivative, and the nitrogen-doped agent used for the nitrogen-doped quinacridone derivative is acridine orange base. By using a quinacridone derivative or a nitrogen-doped quinacridone derivative as the cathode interface material in the organic solar cell, thick film processing of the cathode interface material can be realized, and the conductivity is high, and the electron mobility and energy conversion efficiency of the organic solar cell are high.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to an organic solar cell and a preparation method thereof. Background Art

[0002] Organic solar cells (OSCs) are one of the effective ways to solve environmental pollution and energy crisis. They have great advantages in terms of light weight, flexibility, semi-transparency, large-area low-cost printing, environmental friendliness, etc., and are considered as a new generation of green energy technology with great industrial prospects. In recent years, due to the continuous development of new material synthesis, device structure optimization, active layer morphology regulation, and interfacial layer modification, the power conversion efficiency (PCE) of OSCs has made breakthrough progress. Currently, the power conversion efficiency of single-junction OSCs has exceeded 19% (Advanced. Materials. 2021, 33, 2102420). The commonly used bulk heterojunction OSCs are composed of an active layer, electrodes (including a cathode and an anode), and an interfacial modification layer between the active layer and the electrodes. Among them, introducing a cathode interfacial layer (CIL) between the active layer and the cathode can reduce the electron extraction barrier, promote the formation of an ohmic contact between the active layer and the cathode, and improve the device performance. With the continuous progress of the commercialization process of OSCs, it is required to further improve their power conversion efficiency. Developing cathode interfacial materials with high conductivity and capable of thick-film processing has become one of the important challenges faced by researchers. Although water / alcohol-soluble cathode interfacial materials can effectively improve the power conversion efficiency of OSCs and are easy to process, most of them have low conductivity, resulting in a low thickness of the prepared cathode interfacial layer, generally within 20 nm, which cannot meet the needs of industrial large-area (generally above 100 cm 2 above) production. Summary of the Invention

[0003] The purpose of the present invention is to provide an organic solar cell and a preparation method thereof. The present invention uses quinacridone derivatives or nitrogen-doped quinacridone derivatives as cathode interfacial materials for organic solar cells, which can achieve thick-film processing of cathode interfacial materials, have high conductivity, and high electron mobility and power conversion efficiency of organic solar cells.

[0004] To achieve the above invention purpose, the present invention provides the following technical solutions:

[0005] The present invention provides an organic solar cell, including an anode, an anode interfacial layer, an active layer, a cathode interfacial layer, and a cathode stacked in sequence;

[0006] The photoactive materials used to prepare the active layer include a donor material and an acceptor material. The donor material includes PTB7, PBDB-T, or PM6, and the acceptor material includes PC 71 BM, ITIC, or Y6;

[0007] The cathode interface material used for preparing the cathode interface layer includes quinacridone derivatives or nitrogen-doped quinacridone derivatives. The nitrogen dopant used for the nitrogen-doped quinacridone derivatives is acridine orange base. The quinacridone derivative has the structure shown in Formula I:

[0008]

[0009] Preferably, the material of the anode is indium tin oxide, and the material of the cathode is metal.

[0010] Preferably, the anode interface material used for preparing the anode interface layer includes poly(3,4-ethylenedioxythiophene) and polystyrene sulfonate.

[0011] Preferably, the photoactive material is a mixture of PTB7 and PC 71 BM, or a mixture of PBDB-T and ITIC, or a mixture of PM6 and Y6.

[0012] Preferably, the mass ratio of the donor material to the acceptor material in the photoactive material is 1:(0.8 - 2).

[0013] Preferably, when the cathode interface material is a nitrogen-doped quinacridone derivative, the doping concentration of acridine orange base in the cathode interface layer is 0.47 - 2.82 mol%.

[0014] Preferably, the thickness of the cathode interface layer is 5 - 88 nm.

[0015] The present invention provides a method for preparing the organic solar cell according to the above technical solution, including the following steps:

[0016] Coating an anode interface material solution on the surface of the anode, and forming an anode interface layer on the surface of the anode after removing the solvent;

[0017] Coating a photoactive material solution on the surface of the anode interface layer, and forming an active layer on the surface of the anode interface layer after removing the solvent;

[0018] Coating a cathode interface material solution on the surface of the active layer, and forming a cathode interface layer on the surface of the active layer after removing the solvent;

[0019] Preparing a cathode on the surface of the cathode interface layer to obtain an organic solar cell.

[0020] Preferably, when the cathode interface material used for preparing the cathode interface layer is a quinacridone derivative, the cathode interface material solution is a quinacridone derivative solution; the concentration of the quinacridone derivative solution is 0.25 - 12 mg / mL.

[0021] Preferably, when the cathode interface material used for preparing the cathode interface layer is a nitrogen-doped quinacridone derivative, the preparation method of the cathode interface material solution comprises the following steps:

[0022] Mix a quinacridone derivative, acridine orange base and an alcohol organic solvent to obtain a cathode interface material solution; the concentration of the quinacridone derivative in the cathode interface material solution is 0.25 - 12 mg / mL.

[0023] The present invention provides an organic solar cell, comprising an anode, an anode interface layer, an active layer, a cathode interface layer and a cathode which are stacked in sequence; the photoactive material used for preparing the active layer comprises a donor material and an acceptor material, the donor material comprises PTB7, PBDB-T or PM6, and the acceptor material comprises PC71BM, ITIC or Y6; the cathode interface material used for preparing the cathode interface layer comprises a quinacridone derivative or a nitrogen-doped quinacridone derivative, the nitrogen-doped agent used for the nitrogen-doped quinacridone derivative is acridine orange base, and the quinacridone derivative has the structure shown in Formula I. The present invention uses a quinacridone derivative or a nitrogen-doped quinacridone derivative as the cathode interface material for an organic solar cell, which can realize the thick film processing of the cathode interface material, and the cathode interface material has a high conductivity, the electron mobility and the energy conversion efficiency of the organic solar cell are high, it is suitable for large-scale production, and can meet the needs of industrial large-area production. Description of the Drawings

[0024] Figure 1 is a schematic diagram of the organic solar cell in the present invention;

[0025] Figure 2 The current-voltage curve of the organic solar cell with a PBDB-T:ITIC active layer and a DCNQA-PyBr cathode interface layer with a thickness of 18 nm in Example 1;

[0026] Figure 3 is the current-voltage curve of the organic solar cell with a PBDB-T:ITIC active layer and a DCNQA-PyBr cathode interface layer with a thickness of 88 nm in Example 2;

[0027] Figure 4 is the current-voltage curve of the organic solar cell with a PM6:Y6 active layer and a DCNQA-PyBr cathode interface layer with a thickness of 18 nm in Example 3;

[0028] Figure 5 is the current-voltage curve of the organic solar cell with a PM6:Y6 active layer and a DCNQA-PyBr cathode interface layer with a thickness of 88 nm in Example 4;

[0029] Figure 6 Current-voltage curves of organic solar cells with a PM6:Y6 active layer and a DCNQA-PyBr cathode interface layer or a DCNQA-PyBr:AOB cathode interface layer with a thickness of 27 nm in Examples 6 to 12;

[0030] Figure 7 Current-voltage curves of organic solar cells with a PM6:Y6 active layer and a DCNQA-PyBr cathode interface layer or a DCNQA-PyBr:AOB cathode interface layer with a thickness of 48 nm in Examples 13 to 18;

[0031] Figure 8 Current-voltage curves of organic solar cells with a PM6:Y6 active layer and a DCNQA-PyBr cathode interface layer or a DCNQA-PyBr:AOB cathode interface layer in Examples 19 to 20;

[0032] Figure 9 For Examples 21 to 27, with a PTB7:PC 71 BM active layer and a DCNQA-PyBr cathode interface layer or a DCNQA-PyBr:AOB cathode interface layer with a thickness of 27 nm, current-voltage curves of the organic solar cells

[0033] Figure 10 Conductivity curves of DCNQA-PyBr material and AOB-doped DCNQA-PyBr material in Test Example 1;

[0034] Figure 11 Electron mobility curves of devices with a PM6:Y6 active layer and a DCNQA-PyBr cathode interface layer or a DCNQA-PyBr:AOB cathode interface layer in Test Example 2. Detailed implementation manners

[0035] The present invention provides an organic solar cell, including an anode, an anode interface layer, an active layer, a cathode interface layer, and a cathode stacked in sequence;

[0036] The photoactive materials used to prepare the active layer include a donor material and an acceptor material. The donor material includes PTB7, PBDB-T, or PM6, and the acceptor material includes PC 71 BM, ITIC, or Y6;

[0037] The cathode interface materials used to prepare the cathode interface layer include quinacridone derivatives or nitrogen-doped quinacridone derivatives. The nitrogen-doped agent used for the nitrogen-doped quinacridone derivatives is acridine orange base, and the quinacridone derivative has the structure shown in Formula I:

[0038]

[0039] Figure 1 This is a schematic diagram of the organic solar cell in the present invention. Below, in conjunction with Figure 1 the organic solar cell provided by the present invention will be described in detail.

[0040] The organic solar cell provided by the present invention includes an anode. In the present invention, the material of the anode is preferably indium tin oxide (ITO); the thickness of the anode is preferably 160 - 200 nm, more preferably 170 - 190 nm, and further preferably 180 nm.

[0041] The organic solar cell provided by the present invention includes an anode interface layer laminated on the surface of the anode. Specifically, the anode interface layer is in contact with one side surface of the anode. In the present invention, the anode interface material used to prepare the anode interface layer preferably includes poly(3,4-ethylenedioxythiophene) (PEDOT) and polystyrene sulfonate (PSS); in the present invention, the anode interface layer is preferably prepared from a PEDOT:PSS aqueous solution of model Clevios PVP.Al 4083 produced by Heraeus of Germany, which will be described in detail later. In the embodiments of the present invention, the anode interface layer prepared with PEDOT and PSS as the anode interface material is denoted as the PEDOT:PSS anode interface layer. In the present invention, the thickness of the anode interface layer is preferably 20 - 40 nm, more preferably 25 - 35 nm, and further preferably 30 nm.

[0042] The organic solar cell provided by the present invention includes an active layer laminated on the anode interface layer, that is, the active layer is in contact with one side surface of the anode interface layer. In the present invention, the photoactive materials used to prepare the active layer include a donor material and an acceptor material. The donor material includes PTB7 (CAS No. 1266549-31-8), PBDB-T (CAS No. 145929-80-4), or PM6 (CAS No. 1802013-83-7), and the acceptor material includes PC 71 BM (CAS No. 609771-63-3), ITIC (CAS No. 1664293-06-4), or Y6 (CAS No. 2304444-49-1); specifically, the photoactive material is preferably a mixture of PTB7 and PC 71 BM, or a mixture of PBDB-T and ITIC, or a mixture of PM6 and Y6. In the embodiments of the present invention, the active layer prepared with PTB7 and PC 71 BM as the photoactive material is denoted as PTB7:PC 71BM active layer; The active layer prepared with PBDB-T and ITIC as photoactive materials is denoted as PBDB-T:ITIC active layer; The active layer prepared with PM6 and Y6 as photoactive materials is denoted as PM6:Y6 active layer. In the present invention, the mass ratio of the donor material to the acceptor material is preferably 1:(0.8 - 2), more preferably 1:(1 - 1.5). In the present invention, the thickness of the active layer is preferably 80 - 120 nm, more preferably 90 - 110 nm, and further preferably 100 nm. In the present invention, the PTB7, PC 71 The structural formulas of BM, PBDB-T, ITIC, PM6, and Y6 are specifically as follows:

[0043]

[0044] The organic solar cell provided by the present invention includes a cathode interface layer stacked on the surface of the active layer, that is, the cathode interface layer is in contact with one side surface of the active layer. In the present invention, the cathode interface material used to prepare the cathode interface layer includes quinacridone derivatives (abbreviated as DCNQA-PyBr) or nitrogen-doped quinacridone derivatives. The nitrogen dopant used in the nitrogen-doped quinacridone derivatives is acridine orange base (abbreviated as AOB), and the quinacridone derivative has the structure shown in Formula I:

[0045]

[0046] In the present invention, the structural formula of the acridine orange base is specifically as follows:

[0047]

[0048] In the present invention, the doping concentration of AOB in the cathode interface layer is preferably 0.47 - 2.82 mol%, specifically it can be 0.47 mol%, 0.94 mol%, 1.41 mol%, 1.88 mol%, or 2.82 mol%; The doping concentration of AOB in the present invention specifically refers to the percentage of the amount of substance of AOB in the total amount of substance of AOB and DCNQA-PyBr. In the present invention, the cathode interface layer prepared with DCNQA-PyBr as the cathode interface material is denoted as DCNQA-PyBr cathode interface layer; The cathode interface layer prepared with nitrogen-doped quinacridone derivatives as the cathode interface material (using acridine orange base as the nitrogen dopant) is denoted as DCNQA-PyBr:AOB cathode interface layer. In the present invention, the thickness of the cathode interface layer is preferably 5 - 88 nm, more preferably 18 - 88 nm, further preferably 27 - 88 nm, and even more preferably 48 - 88 nm.

[0049] In the present invention, the DCNQA-PyBr is an ionic compound containing quinacridone. By preparing a cathode interface layer based on DCNQA-PyBr, thick film processing of the cathode interface layer can be achieved. When it is applied in non-fullerene organic solar cells (NF-OSCs), a relatively high energy conversion efficiency is obtained; using acridine orange base as a nitrogen-type dopant to dope DCNQA-PyBr to prepare a cathode interface layer, which can stably exist in solution, so it is convenient to achieve efficient doping through solution coating film-forming technology, which can effectively improve the conductivity of the cathode interface layer and the electron mobility of the organic solar cell, thereby being conducive to improving the energy conversion efficiency of the organic solar cell.

[0050] The solar cell provided by the present invention includes a cathode laminated on the surface of the cathode interface layer, that is, the cathode is in contact with one surface of the cathode interface layer. In the present invention, the material of the cathode is preferably a metal, more preferably silver or aluminum; the thickness of the cathode is preferably 80-120 nm, more preferably 90-110 nm, and further preferably 100 nm.

[0051] The present invention provides a preparation method of the solar cell described in the above technical solution, including the following steps:

[0052] Coat an anode interface material solution on the surface of the anode, and form an anode interface layer on the surface of the anode after removing the solvent;

[0053] Coat a photoactive material solution on the surface of the anode interface layer, and form an active layer on the surface of the anode interface layer after removing the solvent;

[0054] Coat a cathode interface material solution on the surface of the active layer, and form a cathode interface layer on the surface of the active layer after removing the solvent;

[0055] Prepare a cathode on the surface of the cathode interface layer to obtain an organic solar cell.

[0056] In the present invention, unless otherwise specified, the raw materials or reagents used are commercially available products well-known to those skilled in the art or are prepared by methods well-known to those skilled in the art.

[0057] In the present invention, an anode interface material solution is coated on the anode surface, and after removing the solvent, an anode interface layer is formed on the anode surface. In the present invention, when the material of the anode is ITO, the present invention preferably deposits the anode on a substrate by evaporation, and then further prepares an anode interface layer on the anode. In the present invention, the substrate is preferably a glass sheet. The present invention has no special requirements for the specific conditions used for evaporating the anode. Using the evaporation conditions well-known to those skilled in the art, an anode with a thickness meeting the requirements can be obtained. In the present invention, the solvent in the anode interface material solution is preferably water; in the embodiments of the present invention, when the anode interface material is PEDOT and PSS, the anode interface material solution is preferably an aqueous PEDOT:PSS solution purchased from Heraeus GmbH, Germany, with the model number Clevios PVP.Al 4083; the present invention preferably filters the aqueous PEDOT:PSS solution through a 0.45 μm filter membrane before use. In the present invention, the coating method of the anode interface material solution is preferably spin coating, and the speed of the spin coating is preferably 3400 - 3600 r / min, more preferably 3500 r / min; the time of the spin coating is preferably 40 - 60 s, more preferably 50 - 60 s. In the present invention, the method for removing the solvent is preferably annealing treatment; the temperature of the annealing treatment is preferably 100 - 120 °C, more preferably 110 °C; the time of the annealing treatment is preferably 20 - 40 min, more preferably 30 min. Through the annealing treatment, the present invention can remove the moisture in the wet film, thereby being beneficial to improving the stability of the organic solar cell.

[0058] After obtaining the anode interface layer, the present invention coats a photoactive material solution on the surface of the anode interface layer, and after removing the solvent, an active layer is formed on the surface of the anode interface layer. In the present invention, the total concentration of the photoactive material in the photoactive material solution is preferably 18 to 30 mg / mL, more preferably 20 to 26 mg / mL; the present invention has no special limitation on the type of solvent in the photoactive material solution, as long as it can ensure that the photoactive material is fully dissolved. The present invention preferably can also select whether to use additives according to the type of photoactive material. Suitable additives are beneficial to improving the morphology of the active layer and the charge transport situation, and are beneficial to the improvement of the energy conversion efficiency; in the present invention, the additive preferably includes 1,8-diiodooctane or chloronaphthalene, and the volume ratio of the additive to the solvent in the photoactive material solution is preferably (0.5 to 3):(99.5 to 97). In the examples of the present invention, when the photoactive material is PBDB-T and ITIC, the solvent used is preferably chlorobenzene, and the additive used is preferably 1,8-diiodooctane, and the volume ratio of the solvent to the additive is preferably 99.5:0.5; when the photoactive material is PM6 and Y6, the solvent used is preferably chloroform, and the additive used is preferably chloronaphthalene, and the volume ratio of the solvent to the additive is preferably 99.5:0.5; when the photoactive material is PTB7 and PC 71 BM, the solvent used is preferably chlorobenzene, and the additive used is preferably 1,8-diiodooctane, and the volume ratio of the solvent to the additive is preferably 97:3. In the present invention, the coating method of the photoactive material solution is preferably spin coating, and the speed of the spin coating is preferably 3400 to 3600 r / min, more preferably 3500 r / min; the present invention has no special requirement for the spin coating time, as long as the thickness of the active layer meets the requirements after the solvent in the wet film obtained by spin coating is removed. In the present invention, the method for removing the solvent is preferably annealing treatment or drying, and the present invention preferably selects a suitable method for removing the solvent according to the type of photoactive material. Specifically, in the present invention, when the photoactive material is PBDB-T and ITIC, or PM6 and Y6, the solvent is preferably removed by annealing treatment; the temperature of the annealing treatment is preferably 70 to 110 °C, more preferably 80 to 100 °C; the time of the annealing treatment is preferably 10 to 30 min, more preferably 20 min. The present invention can remove the solvent in the wet film through the annealing treatment, thereby forming an active layer on the surface of the anode interface layer; and through the annealing treatment, the morphology and crystallinity of the active layer can be changed, and a channel beneficial to charge transport can be formed, thereby improving the energy conversion efficiency of the device. In the present invention, when the photoactive material is PTB7 and PC 71When removing the solvent in BM, a drying method is preferably adopted, and the drying is preferably vacuum drying, and the conditions of the vacuum drying are only required to ensure that the solvent in the wet film can be fully removed; in the embodiments of the present invention, specifically, it is vacuum dried in the glove box transition chamber for 12 h.

[0059] After obtaining the active layer, the present invention coats a cathode interface material solution on the surface of the active layer, and after removing the solvent, a cathode interface layer is formed on the surface of the active layer. In the present invention, the solvent of the cathode interface material solution is preferably methanol. In the present invention, when the cathode interface material is DCNQA-PyBr, the cathode interface material solution is preferably a DCNQA-PyBr solution, specifically obtained by dissolving DCNQA-PyBr in methanol; the concentration of the DCNQA-PyBr solution is preferably 0.25-12 mg / mL, more preferably 2-4 mg / mL. In the present invention, when the cathode interface material is nitrogen-doped DCNQA-PyBr (the nitrogen dopant used is AOB), the preparation method of the cathode interface material solution preferably includes the following steps: mixing DCNQA-PyBr, AOB with an alcohol organic solvent to obtain a cathode interface material solution; the alcohol organic solvent is preferably methanol. In the embodiments of the present invention, specifically, DCNQA-PyBr and AOB are respectively dissolved in methanol, and then the obtained DCNQA-PyBr solution and AOB solution are mixed and stirred for 0.5-2 h to obtain a cathode interface material solution; the concentration of DCNQA-PyBr in the cathode interface material solution is preferably 0.25-12 mg / mL, more preferably 2-4 mg / mL; the concentration and volume ratio of the DCNQA-PyBr solution and the AOB solution only need to ensure that the AOB doping concentration in the cathode interface layer meets the requirements. In the present invention, the coating method of the cathode interface material solution is preferably spin coating, and the spin coating speed is preferably 1900-2100 r / min, more preferably 2000 r / min; the present invention has no special requirements for the spin coating time, and only needs to ensure that the solvent in the wet film obtained after spin coating is removed to obtain a cathode interface layer with a thickness meeting the requirements. The present invention preferably removes the solvent in the wet film by negative pressure vacuum treatment.

[0060] After obtaining the cathode interface layer, the present invention prepares a cathode on the surface of the cathode interface layer to obtain an organic solar cell. In the present invention, when the material of the cathode is a metal, the present invention preferably evaporates and deposits the cathode on the surface of the cathode interface layer; in the present invention, the metal raw material used for evaporating and depositing the cathode is a commercially available product well-known to those skilled in the art, and the present invention has no special limitation on the form of the metal raw material, and specifically can be metal powder, metal bar, metal sheet or metal block. In the present invention, the evaporation and deposition speed is preferably more preferably even more preferably The vacuum degree of the evaporation coating is preferably (1.7 - 1.9)×10 -4 Pa, more preferably 1.8×10 -4 Pa; the current of the evaporation coating is preferably 32 - 40 A, more preferably 34 - 37 A; the voltage of the evaporation coating is preferably 2 - 4 V, more preferably 3.5 - 4 V; the time of the evaporation coating is based on ensuring that the cathode with a thickness meeting the requirements is obtained.

[0061] The technical solutions in the present invention will be clearly and completely described below in conjunction with the embodiments in the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without making creative efforts belong to the scope of protection of the present invention.

[0062] DCNQA - PyBr involved in the following embodiments was prepared with reference to the literature (J. Mater. Chem. A, 2016, 4, 2169 - 2177), and specifically includes the following steps:

[0063] QA - PyBr (1.74 g, 2.50 mmol, the structural formula is as shown in Formula II), malononitrile (0.33 g, 5.00 mmol) and 300 mL of dry CH2Cl2 were placed in a 500 mL three - necked flask. TiCl4 (14.25 g, 75.0 mmol) was added dropwise to the three - necked flask in an ice - water bath at 0 °C. After the addition was completed, it was stirred for 10 min, and then dry pyridine (31.60 g, 400.0 mmol) was added dropwise. After the addition was completed, it was naturally warmed to room temperature (25 °C) and reacted for 24 h; after the reaction ended, all the solvents in the obtained product system were rotary - evaporated, and the obtained residue was separated by silica gel column chromatography with 200 - 300 mesh using dichloromethane as the eluent, and the obtained dark green solid was DCNQA - Br (1.34 g, 68%).

[0064]

[0065] DCNQA - Br (1.98 g, 2.50 mmol) and 100 mL of pyridine were placed in a 250 mL three - necked flask, heated under reflux overnight, precipitates gradually separated out in the system. After cooling to room temperature, it was filtered, and the filter cake was washed with 100 mL of CH2Cl2 and dried, and the obtained dark green solid was DCNQA - PyBr (2.15 g, 81%).

[0066] Elemental analysis was performed on the prepared product to confirm that the product was DCNQA - PyBr.

[0067] Example 1

[0068] To fabricate an ITO / PEDOT:PSS / PBDB-T:ITIC / DCNQA-PyBr / Al organic solar cell, the steps are as follows:

[0069] Deposit ITO with a thickness of 160 nm on a glass substrate as the anode;

[0070] Filter an aqueous solution of PEDOT:PSS (purchased from Heraeus GmbH, Germany, model Clevios PVP.Al4083) with a 0.45 μm filter membrane, then spin-coat it on the surface of the anode at a speed of 3500 r / min and anneal at 110 °C for 30 min to form a PEDOT:PSS anode interfacial layer with a thickness of 35 nm on the anode surface, obtaining an ITO / PEDOT:PSS device, and then transfer it to a glove box;

[0071] Mix PBDB-T, ITIC, 1,8-diiodooctane and chlorobenzene to obtain a photoactive material solution. The mass ratio of PBDB-T to ITIC in the photoactive material solution is 1:1, the total concentration of PBDB-T and ITIC is 20 mg / mL, and the volume ratio of chlorobenzene to 1,8-diiodooctane is 99.5:0.5; Spin-coat the photoactive material solution on the surface of the PEDOT:PSS anode interfacial layer at a speed of 3500 r / min and anneal at 110 °C for 30 min to form a PBDB-T:ITIC active layer with a thickness of 100 nm on the surface of the PEDOT:PSS anode interfacial layer, obtaining an ITO / PEDOT:PSS / PBDB-T:ITIC device;

[0072] Use a methanol solution of DCNQA-PyBr with a concentration of 3 mg / mL as the cathode interfacial material solution. Spin-coat the cathode interfacial material solution on the surface of the PBDB-T:ITIC active layer at a speed of 2000 r / min for 40 s, and then remove the solvent by vacuum pumping to form a DCNQA-PyBr cathode interfacial layer with a thickness of 18 nm on the surface of the PBDB-T:ITIC active layer, obtaining an ITO / PEDOT:PSS / PBDB-T:ITIC / DCNQA-PyBr device;

[0073] Place the ITO / PEDOT:PSS / PBDB-T:ITIC / DCNQA-PyBr device in an evaporation chamber, and at a speed, deposit an aluminum metal layer with a thickness of 100 nm on the surface of the DCNQA-PyBr cathode interfacial layer as the cathode to obtain an ITO / PEDOT:PSS / PBDB-T:ITIC / DCNQA-PyBr / Al organic solar cell.

[0074] The organic solar cells prepared in this example were subjected to performance tests, and the results are as Figure 2 shown. Figure 2 It shows that the open-circuit voltage of the organic solar cell is 0.88 V, the short-circuit current density is 15.71 mA / cm 2 , the fill factor is 0.677, and the energy conversion efficiency of the organic solar cell is calculated to be 9.35%.

[0075] Example 2

[0076] The ITO / PEDOT:PSS / PBDB-T:ITIC / DCNQA-PyBr / Al organic solar cell was prepared according to the method of Example 1, except that: the concentration of the DCNQA-PyBr methanol solution was 12 mg / mL, the spinning speed of the DCNQA-PyBr methanol solution was 1000 r / min, and the thickness of the DCNQA-PyBr cathode interface layer was 88 nm.

[0077] The organic solar cells prepared in this example were subjected to performance tests, and the results are as Figure 3 shown. Figure 3 It shows that the open-circuit voltage of the organic solar cell is 0.865 V, the short-circuit current density is 11.44 mA / cm 2 , the fill factor is 0.662, and the energy conversion efficiency of the organic solar cell is calculated to be 6.55%.

[0078] Example 3

[0079] The ITO / PEDOT:PSS / PM6:Y6 / DCNQA-PyBr / Al organic solar cell was prepared according to the method of Example 1, except that the active layer was prepared as follows:

[0080] PM6, Y6, chloronaphthalene and chloroform were mixed to obtain a photoactive material solution. The mass ratio of PM6 to Y6 in the photoactive material solution was 1:1.2, the total concentration of PM6 and Y6 was 16 mg / mL, and the volume ratio of chloroform to chloronaphthalene was 99.5:0.5; the photoactive material solution was spin-coated on the surface of the PEDOT:PSS anode interface layer at a speed of 3500 r / min and annealed at 70 °C for 10 min to form a PM6:Y6 active layer with a thickness of 100 nm on the surface of the PEDOT:PSS anode interface layer.

[0081] The organic solar cells prepared in this example were subjected to performance tests, and the results are as Figure 4 shown. Figure 4 It shows that the open-circuit voltage of the organic solar cell is 0.855 V, the short-circuit current density is 24.98 mA / cm 2, the fill factor is 0.727, and the calculated energy conversion efficiency of the organic solar cell is 15.52%.

[0082] Example 4

[0083] Prepare the ITO / PEDOT:PSS / PM6:Y6 / DCNQA-PyBr / Al organic solar cell according to the method of Example 3, with the only difference being that: the concentration of the DCNQA-PyBr methanol solution is 12 mg / mL, the spinning speed of the DCNQA-PyBr methanol solution is 1000 r / min, and the thickness of the DCNQA-PyBr cathode interface layer is 88 nm.

[0084] Perform performance tests on the organic solar cell prepared in this example, and the results are as Figure 5 shown. Figure 5 It shows that the open-circuit voltage of the organic solar cell is 0.845 V, the short-circuit current density is 21.16 mA / cm 2 , the fill factor is 0.72, and the calculated energy conversion efficiency of the organic solar cell is 12.88%.

[0085] Example 5

[0086] Dissolve DCNQA-PyBr in methanol and stir at room temperature for 30 min to obtain a DCNQA-PyBr methanol solution with a concentration of 3 mg / mL; dissolve AOB (purchased from Sigma-Aldrich and used after multiple sublimation purifications) in methanol and stir at room temperature for 30 min to obtain an AOB methanol solution with a concentration of 3 mg / mL; mix different volumes of the AOB methanol solution with the DCNQA-PyBr methanol solution and stir at room temperature for 30 min to obtain AOB-doped DCNQA-PyBr methanol solutions with different doping concentrations.

[0087] Examples 6 - 12

[0088] Prepare an ITO / PEDOT:PSS / PM6:Y6 / DCNQA-PyBr / Al organic solar cell or an ITO / PEDOT:PSS / PM6:Y6 / DCNQA-PyBr:AOB / Al organic solar cell according to the method of Example 3, except that: the cathode interface material solutions are a DCNQA-PyBr methanol solution and an AOB-doped DCNQA-PyBr methanol solution respectively, the concentration of DCNQA-PyBr in both the DCNQA-PyBr methanol solution and the AOB-doped DCNQA-PyBr methanol solution is 5 mg / mL, and the doping concentrations of AOB in the AOB-doped DCNQA-PyBr methanol solution are 0.47 mol%, 0.94 mol%, 1.41 mol%, 1.88 mol%, 2.35 mol% and 2.82 mol% respectively; and the thicknesses of the obtained DCNQA-PyBr cathode interface layer and the DCNQA-PyBr:AOB cathode interface layer are 27 nm;

[0089] Among them, the AOB-doped DCNQA-PyBr methanol solution is prepared according to the method of Example 5 (the relevant concentrations can be adjusted adaptively to ensure that an AOB-doped DCNQA-PyBr methanol solution with the required concentration can be obtained).

[0090] Perform performance tests on the organic solar cells prepared in Examples 6 to 12, and the results are as Figure 6 shown, and the specific data are listed in Table 1. From Figure 6 Table 1, it can be seen that doping DCNQA-PyBr with AOB as the cathode interface layer is beneficial to the improvement of the short-circuit current density and the fill factor, thereby improving the energy conversion efficiency of the organic solar cell.

[0091] Table 1 Performance test data of the organic solar cells prepared in Examples 6 to 12

[0092]

[0093] Examples 13 to 18

[0094] Prepare an ITO / PEDOT:PSS / PM6:Y6 / DCNQA-PyBr / Al organic solar cell or an ITO / PEDOT:PSS / PM6:Y6 / DCNQA-PyBr:AOB / Al organic solar cell according to the method of Example 3, with the only difference being that the cathode interface material solutions are a DCNQA-PyBr methanol solution and a DCNQA-PyBr methanol solution doped with AOB respectively. The concentration of DCNQA-PyBr in both the DCNQA-PyBr methanol solution and the DCNQA-PyBr methanol solution doped with AOB is 10 mg / mL, and the doping concentrations of AOB in the DCNQA-PyBr methanol solution doped with AOB are 0.47 mol%, 0.94 mol%, 1.41 mol%, 1.88 mol% and 2.82 mol% respectively; and the thicknesses of the obtained DCNQA-PyBr cathode interface layer and the DCNQA-PyBr:AOB cathode interface layer are 48 nm;

[0095] Among them, the DCNQA-PyBr methanol solution doped with AOB is prepared according to the method of Example 5 (the relevant concentrations can be adjusted adaptively to ensure that a DCNQA-PyBr methanol solution doped with AOB with the required concentration can be obtained).

[0096] Perform performance tests on the organic solar cells prepared in Examples 13 to 18, and the results are as Figure 7 shown, and the specific data are listed in Table 2. From Figure 7 Table 2, it can be seen that by increasing the thickness of the cathode interface layer to 48 nm, it can be found that doping DCNQA-PyBr with AOB as the cathode interface layer is also beneficial to the improvement of the short-circuit current density and the fill factor, thereby improving the energy conversion efficiency of the organic solar cell.

[0097] Table 2 Performance test data of the organic solar cells prepared in Examples 13 to 18

[0098]

[0099] Example 19

[0100] Prepare an ITO / PEDOT:PSS / PM6:Y6 / DCNQA-PyBr / Ag organic solar cell according to the method of Example 3, with the only difference being that a silver metal layer is used as the cathode.

[0101] Example 20

[0102] The ITO / PEDOT:PSS / PM6:Y6 / DCNQA-PyBr:AOB / Ag organic solar cell was fabricated according to the method of Example 19, except that: the cathode interface material solution was a methanol solution of DCNQA-PyBr doped with AOB, and the doping concentration of AOB in the methanol solution of DCNQA-PyBr doped with AOB was 0.94 mol%; wherein, the methanol solution of DCNQA-PyBr doped with AOB was prepared according to the method of Example 5 (the relevant concentrations can be adjusted adaptively to ensure that a methanol solution of DCNQA-PyBr doped with AOB with the required concentration can be obtained).

[0103] The performance of the organic solar cells prepared in Examples 19 to 20 was tested, and the results are as Figure 8 shown. Figure 8 It shows that the open-circuit voltage of the organic solar cell prepared in Example 19 was 0.845 V, the short-circuit current density was 25.04 mA / cm 2 , the fill factor was 0.746, and the calculated energy conversion efficiency was 15.77%; the open-circuit voltage of the organic solar cell prepared in Example 20 was 0.84 V, the short-circuit current density was 25.51 mA / cm 2 , the fill factor was 0.761, and the calculated energy conversion efficiency was 16.3%. This shows that in the organic solar cell with Ag as the cathode, AOB-doped DCNQA-PyBr as the cathode interface layer is not only beneficial to the improvement of the short-circuit current density and the fill factor, but also obtains an energy conversion efficiency as high as 16.3%.

[0104] Examples 21 to 27

[0105] Fabricate ITO / PEDOT:PSS / PTB7:PC 71 BM / DCNQA-PyBr / Al organic solar cells or ITO / PEDOT:PSS / PTB7:PC 71 BM / DCNQA-PyBr:AOB / Al organic solar cells, the steps are as follows:

[0106] Deposit 160 nm thick ITO on a glass substrate as the anode;

[0107] Filter the aqueous PEDOT:PSS solution (purchased from Heraeus GmbH, Germany, model Clevios PVP.Al4083) with a 0.45 μm filter membrane, then spin-coat it on the surface of the anode at a speed of 3500 r / min and anneal it at 110 °C for 30 min to form a 35 nm thick PEDOT:PSS anode interface layer on the surface of the anode, obtaining an ITO / PEDOT:PSS device, and then transfer it to a glove box;

[0108] PTB7 (purchased from 1-Material Co., Canada), PC 71 BM (purchased from American DyeSource, USA), 1,8-diiodooctane and chlorobenzene were mixed to obtain a photoactive material solution. In the photoactive material solution, the mass ratio of PTB7 to PC 71 BM is 1:1.5, and the total concentration of PTB7 and PC 71 BM is 25 mg / mL. The volume ratio of chlorobenzene to 1,8-diiodooctane is 97:3. The photoactive material solution was spin-coated on the surface of the PEDOT:PSS anode interface layer at a speed of 1000 r / min and vacuum-dried in the glove box transfer chamber for 12 h to form a PTB7:PC 71 BM active layer with a thickness of 100 nm on the surface of the PEDOT:PSS anode interface layer, and an ITO / PEDOT:PSS / PTB7:PC 71 BM device was obtained;

[0109] The DCNQA-PyBr methanol solution and the AOB-doped DCNQA-PyBr methanol solution were used as the cathode interface material solutions respectively. The cathode interface material solutions were spin-coated on the surface of the PTB7:PC 71 BM active layer at a speed of 2000 r / min for 40 s, and then the solvent was removed by negative pressure vacuum treatment to form a DCNQA-PyBr cathode interface layer with a thickness of 27 nm or a DCNQA-PyBr:AOB cathode interface layer with a thickness of 27 nm on the surface of the PTB7:PC 71 BM active layer respectively. On this basis, an ITO / PEDOT:PSS / PTB7:PC 71 BM / DCNQA-PyBr device or an ITO / PEDOT:PSS / PTB7:PC 71 BM / DCNQA-PyBr:AOB device was obtained. The concentration of DCNQA-PyBr in the DCNQA-PyBr methanol solution and the AOB-doped DCNQA-PyBr methanol solution is 5 mg / mL, and the doping concentrations of AOB in the AOB-doped DCNQA-PyBr methanol solution are 0.47 mol%, 0.94 mol%, 1.41 mol%, 1.88 mol%, 2.82 mol% and 3.76 mol% respectively;

[0110] The ITO / PEDOT:PSS / PTB7:PC 71 BM / DCNQA-PyBr device and the ITO / PEDOT:PSS / PTB7:PC 71 BM / DCNQA-PyBr:AOB device were placed in the evaporation chamber respectively, and At a speed, an aluminum metal layer with a thickness of 100 nm was evaporated on the surface of the cathode interface layer as the cathode, and ITO / PEDOT:PSS / PTB7:PC 71 BM / DCNQA-PyBr / Al organic solar cells and ITO / PEDOT:PSS / PTB7:PC 71 BM / DCNQA-PyBr:AOB / Al organic solar cells were obtained respectively.

[0111] The organic solar cells prepared in Examples 21 to 27 were subjected to performance tests, and the results were as Figure 9 shown, and the specific data are listed in Table 3. From Figure 9 Table 3, it can be seen that in the fullerene system with PTB7:PC 71 BM as the active layer, it can be found that doping AOB into DCNQA-PyBr as the cathode interface layer is also beneficial to the improvement of the short-circuit current density and the fill factor, thereby improving the energy conversion efficiency of the organic solar cell.

[0112] Table 3 Performance test data of the organic solar cells prepared in Examples 21 to 27

[0113]

[0114] Test Example 1

[0115] In order to test the change in conductivity before and after doping AOB into DCNQA-PyBr, the following experiment was carried out:

[0116] ITO with a thickness of 160 nm was evaporated on a glass substrate as the anode, and then placed in an evaporation chamber. At a speed, an aluminum metal layer was evaporated on the surface of the anode to obtain an ITO / Al device;

[0117] A DCNQA-PyBr methanol solution or an AOB-doped DCNQA-PyBr methanol solution was used as the cathode interface material solution, and was spin-coated on the surface of the aluminum metal layer at a speed of 2000 r / min for 40 s to form a wet film on the surface of the aluminum metal layer; among them, the concentration of DCNQA-PyBr in the DCNQA-PyBr methanol solution and the AOB-doped DCNQA-PyBr methanol solution was 3 mg / mL, the doping concentration of AOB in the AOB-doped DCNQA-PyBr methanol solution was 0.94 mol%, and the AOB-doped DCNQA-PyBr methanol solution was prepared according to the method of Example 5 (the relevant concentrations can be adjusted adaptively to ensure that an AOB-doped DCNQA-PyBr methanol solution with the required concentration can be obtained);

[0118] The device obtained after spin coating was placed in an evaporation chamber. At a An aluminum metal layer is evaporated on the device at a speed of, and the solvent in the wet film is removed during the evaporation process to form a DCNQA-PyBr cathode interface layer and a DCNQA-PyBr:AOB cathode interface layer, respectively, to finally obtain an ITO / Al / DCNQA-PyBr / Al device and an ITO / Al / DCNQA-PyBr:AOB / Al device; in the ITO / Al / DCNQA-PyBr / Al device and the ITO / Al / DCNQA-PyBr:AOB / Al device, the thickness of the aluminum metal layer is 100 nm, and the thickness of the DCNQA-PyBr cathode interface layer and the DCNQA-PyBr:AOB cathode interface layer are both 45 nm.

[0119] The ITO / Al / DCNQA-PyBr / Al device and the ITO / Al / DCNQA-PyBr:AOB / Al device were tested for current-voltage relationship. The results are as follows: Figure 10 The conductivity of the material is calculated by the formula σ = IL / (US), where σ represents conductivity, I represents current, L is the material thickness (L = 45nm), U is the voltage, and S is the area of the device (0.04cm 2 ). By calculation, it can be concluded that the conductivity of DCNQA-PyBr material is 7.2×10 -4 S / cm, the conductivity of AOB-doped DCNQA-PyBr material is 1.02×10 -3 S / cm. This shows that the conductivity of DCNQA-PyBr can be improved by AOB doping.

[0120] Test Example 2

[0121] In order to test the changes in the electron transport capacity before and after AOB doping DCNQA-PyBr, the following experiments were performed:

[0122] ITO with a thickness of 160 nm was evaporated on a glass substrate as an anode;

[0123] 500 mg of zinc acetate dihydrate, 5 mL of dimethoxyethanol and 140 μL of ethanolamine were mixed, and the mixture was stirred at room temperature for 8 h to obtain a ZnO precursor solution; the ZnO precursor solution was spin-coated on the surface of the anode at a speed of 4000 r / min, and annealed at 200° C. for 30 min to obtain a ZnO film with a thickness of 30 nm on the surface of the anode to obtain an ITO / ZnO device, which was then transferred to a glove box;

[0124] Mix PM6, Y6, chloro-naphthalene and chloroform to obtain a photoactive material solution. In the photoactive material solution, the mass ratio of PM6 to Y6 is 1:1.2, the total concentration of PM6 and Y6 is 16 mg / mL, and the volume ratio of chloroform to chloro-naphthalene is 99.5:0.5. Spin-coat the photoactive material solution on the surface of the ZnO film at a speed of 2500 r / min, and anneal it at 70 °C for 10 min to form a PM6:Y6 active layer with a thickness of 90 nm on the surface of the ZnO film, thus obtaining an ITO / ZnO / PM6:Y6 device.

[0125] Use the DCNQA-PyBr methanol solution or the AOB-doped DCNQA-PyBr methanol solution as the cathode interface material solution, and spin-coat it on the surface of the aluminum metal layer at a speed of 2000 r / min for 40 s to form a wet film on the surface of the PM6:Y6 active layer. Among them, the concentration of DCNQA-PyBr in both the DCNQA-PyBr methanol solution and the AOB-doped DCNQA-PyBr methanol solution is 3 mg / mL, the doping concentration of AOB in the AOB-doped DCNQA-PyBr methanol solution is 0.94 mol%, and the AOB-doped DCNQA-PyBr methanol solution is prepared according to the method of Example 5 (the relevant concentrations can be adjusted appropriately to ensure that the AOB-doped DCNQA-PyBr methanol solution with the required concentration can be obtained).

[0126] Place the device obtained after spin-coating in the evaporation chamber at a speed to evaporate and deposit an aluminum metal layer with a thickness of 100 nm on the device respectively. During the evaporation and deposition process, the solvent in the wet film is removed to form a DCNQA-PyBr cathode interface layer or a DCNQA-PyBr:AOB cathode interface layer with a thickness of 18 nm respectively, and finally obtain an ITO / ZnO / PM6:Y6 / DCNQA-PyBr / Al device and an ITO / ZnO / PM6:Y6 / DCNQA-PyBr:AOB / Al device.

[0127] Perform current-voltage relationship tests on the ITO / ZnO / PM6:Y6 / DCNQA-PyBr / Al device and the ITO / ZnO / PM6:Y6 / DCNQA-PyBr:AOB / Al device obtained by the above method, and the results are as Figure 11 shown. The electron mobility of the material is calculated by the formula where J is the current density, ε0 is the vacuum permittivity, ε r is the relative permittivity (the ε r of the PM6:Y6 active layer = 2.45), μ is the mobility, V is the scanning voltage of the instrument, V bi is the voltage drop between the two electrodes, V ris the voltage drop generated by the resistor, and L is the thickness of the PM6:Y6 active layer (L = 90 nm). Through calculation, the electron mobility of the device with the DCNQA-PyBr cathode interface layer can be obtained as 9.6×10 -4 cm 2 s -1 V -1 , and the electron mobility of the device with the DCNQA-PyBr:AOB cathode interface layer is 2.12×10 -3 cm 2 s -1 V -1 . This shows that doping with AOB can improve the electron mobility of the device, giving it a higher electron transport ability.

[0128] As can be seen from the above embodiments, the present invention is based on DCNQA-PyBr to prepare a cathode interface layer and apply it to non-fullerene (such as PBDB-T:ITIC system and PM6:Y6 system) organic solar cells. The thickness of the DCNQA-PyBr cathode interface layer can be broadened to 88 nm, and at the same time, it can still ensure that the organic solar cell has a high energy conversion efficiency, which can meet the industrial production requirement for an energy conversion efficiency greater than 10%. Moreover, the relatively high thickness reduces the pinholes and defects of the cathode interface layer and is easy to process.

[0129] At the same time, the present invention is based on doping DCNQA-PyBr with AOB to prepare a cathode interface layer, which can effectively improve the conductivity, and can effectively enhance the electron mobility and energy conversion efficiency of the organic solar cell. Moreover, the doping method is very simple. Only by mixing the methanol solution of AOB and the methanol solution of DCNQA-PyBr evenly can the doping effect be achieved. Most nitrogen-based dopants in the prior art are doped through vacuum thermal evaporation technology, which will generate a relatively high temperature during the evaporation process, having an adverse effect on the energy conversion efficiency and stability of the device. Moreover, using vacuum evaporation technology in industry has a relatively high cost. The present invention realizes doping through solution coating and film-forming technology, which is simple, efficient and low-cost.

[0130] The above is only the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can still be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. An organic solar cell, comprising an anode, an anode interface layer, an active layer, a cathode interface layer, and a cathode which are sequentially stacked; The photoactive material used to prepare the active layer includes a donor material and an acceptor material. The donor material includes PBDB-T or PM6, and the acceptor material includes ITIC or Y6; the photoactive material is a mixture of PBDB-T and ITIC, or a mixture of PM6 and Y6; The cathode interface material used to prepare the cathode interface layer is a nitrogen-doped quinacridone derivative. The nitrogen-doped agent used for the nitrogen-doped quinacridone derivative is acridine orange base, and the doping concentration of acridine orange base in the cathode interface layer is 0.47 - 1.88 mol%; the quinacridone derivative has the structure shown in Formula I: Formula I.

2. The organic solar cell according to claim 1, wherein The material of the anode is indium tin oxide, and the material of the cathode is a metal.

3. The organic solar cell according to claim 1, wherein The anode interface material used to prepare the anode interface layer includes poly(3,4-ethylenedioxythiophene) and polystyrene sulfonate.

4. The organic solar cell according to claim 1, characterized in that, The mass ratio of the donor material to the acceptor material in the photoactive material is 1:(0.8 - 2).

5. The organic solar cell according to claim 1, characterized in that, The thickness of the cathode interface layer is 5 - 88 nm.

6. The preparation method of the organic solar cell according to any one of claims 1 - 5, comprising the following steps: Coating an anode interface material solution on the surface of the anode, and forming an anode interface layer on the surface of the anode after removing the solvent; Coating a photoactive material solution on the surface of the anode interface layer, and forming an active layer on the surface of the anode interface layer after removing the solvent; Coating a cathode interface material solution on the surface of the active layer, and forming a cathode interface layer on the surface of the active layer after removing the solvent; Preparing a cathode on the surface of the cathode interface layer to obtain an organic solar cell.

7. The preparation method according to claim 6, characterized in that, The preparation method of the cathode interface material solution includes the following steps: Mixing a quinacridone derivative, acridine orange base with an alcohol organic solvent to obtain a cathode interface material solution; the concentration of the quinacridone derivative in the cathode interface material solution is 0.25 - 12 mg / mL.

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