Preparation and application of organic solar cell based on composite hole transport material

Abstract

The invention discloses an organic solar cell of a composite hole transport material and preparation and application thereof, and belongs to the field of organic photoelectric materials and devices. The composite p-type hole transport material comprises a topological insulator nanometer material and an organic p-type hole transport material film. The topological insulator nano material is uniformly mixed in the organic p-type hole transport material thin film; the topological insulator nano material is niobium arsenide (NbAs) or niobium phosphide (NbP). The material has the advantages of high conductivity, high light transmittance, excellent hole transmission capability, controllable thickness, high stability and the like; the photoelectric conversion efficiency of the organic solar cell can reach more than 16% by using the topological insulator doped composite p-type hole transport material, and the practical application of the organic solar cell is promoted.

Description

Technical Field

[0001] The present invention relates to the technical field of organic optoelectronic materials and devices, and particularly to the preparation and application of an organic solar cell based on a composite hole transport material. Background Art

[0002] As an important clean energy power generation technology, solar cells can directly convert solar energy into electrical energy through the photovoltaic effect. Among them, organic solar cells (OSCs), also known as organic photovoltaic (OPV) devices, as the latest generation of solar cell technology, have significant characteristics such as light weight, easy bending and folding, low manufacturing cost, and environmental friendliness. However, their relatively low power conversion efficiency and poor stability are the main challenges restricting the practical application of OSC devices.

[0003] To solve these problems, in addition to relying on the continuous optimization of device structures and the development of various novel non-fullerene materials, interface engineering strategies also play a crucial role in improving the efficiency and stability of OSCs. Generally speaking, using an appropriate interface layer, such as a hole transport layer (HTL), can effectively reduce interface barriers, promote charge transport, and optimize the optical transmittance of OSCs, thereby improving device efficiency. In organic photovoltaics, traditional anode interface layers often use p-type organic materials such as poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) or binary oxide inorganic materials as hole transport layers, mainly relying on their good hole transport characteristics, high transparency, solution processability, and high work function (about 5.1 eV) that can match most photoactive layers. However, PEDOT:PSS has a low conductivity, is acidic and hygroscopic, which will have an adverse impact on the performance of the OSC in contact with the electrode. Therefore, it is necessary to develop new hole transport materials to improve the performance of OSCs. Summary of the Invention

[0004] In view of this, in order to solve the technical problem that PEDOT:PSS has a low conductivity, is acidic and hygroscopic, which will have an adverse effect on the performance of the contacted electrode OSC, the present invention proposes an organic solar cell based on a composite hole transport material modified by topological insulators, its preparation method and application. This material has the advantages of high conductivity, high light transmittance, excellent hole transport ability, controllable thickness, high stability, etc. The material doped topological insulator nanomaterials into the organic p-type hole transport material film. By using its high carrier density and excellent conductivity, the conductivity of PEDOT:PSS can be effectively improved, thereby enhancing the hole transport ability and exciton dissociation efficiency of the device. In addition, the topological insulator nanomaterials can have an electrostatic interaction with PSS, reducing the free sulfonate ions of PEDOT:PSS, thereby reducing the solution acidity. Finally, the present invention realizes a highly efficient and stable organic solar cell, and its photoelectric conversion efficiency reaches more than 16%, and it is expected to explore practical applications.

[0005] The object of the present invention can be achieved by the following technical solutions:

[0006] A composite p-type hole transport material, the composite p-type hole transport material includes topological insulator nanomaterials and an organic p-type hole transport material;

[0007] The topological insulator nanomaterials are uniformly mixed in the organic p-type hole transport material;

[0008] The topological insulator nanomaterials are niobium arsenide (NbAs) or niobium phosphide (NbP);

[0009] Furthermore, the surface of the composite p-type hole transport material is flat and dense.

[0010] Optionally, the root mean square roughness of the surface of the composite p-type hole transport material is 0.5 nm to 10 nm;

[0011] Preferably, the root mean square roughness of the surface of the composite p-type hole transport material is 0.5 nm to 3 nm.

[0012] Optionally, the root mean square roughness of the surface of the composite p-type hole transport material independently selects any value from 0.5 nm, 1.0 nm, 1.5 nm, 2.0 nm, 2.5 nm, 3.0 nm, 3.5 nm, 4.0 nm, 4.5 nm, 5.0 nm, 5.5 nm, 6.0 nm, 6.5 nm, 7.0 nm, 7.5 nm, 8.0 nm, 8.5 nm, 9.0 nm, 9.5 nm, 10 nm.

[0013] Optionally, the thickness of the composite p-type hole transport material is 5 nm to 100 nm;

[0014] Preferably, the thickness of the composite p-type hole transport material is 10 nm to 50 nm.

[0015] Optionally, the thickness of the composite p-type hole transport material is independently selected from any value among 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, and 100 nm.

[0016] Optionally, the size of the topological insulator nanomaterial is 5 nm to 100 nm;

[0017] Preferably, the size of the topological insulator nanomaterial is 10 nm to 50 nm.

[0018] Optionally, the size of the topological insulator nanomaterial is independently selected from any value among 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, and 100 nm.

[0019] Optionally, the organic p-type hole transport material is selected from at least one of poly(3,4-ethylenedioxythiophene): polystyrenesulfonate, polyaniline, polypyrrole, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], and 2,2',7,7'-tetrakis[N,N-bis(4-methoxyphenyl)amino]-9,9'-spirobifluorene.

[0020] The average light transmittance of the composite p-type hole transport material at 350 - 900 nm is above 95%.

[0021] The present invention provides a preparation method of a composite p-type hole transport material, and the preparation process of this method is simple, low-cost, and has wide universality.

[0022] The above-mentioned preparation method of the composite p-type hole transport material includes the following steps:

[0023] S1. Put the topological insulator bulk material into an organic solvent, decompose it into nanosize by means of cell disruption or ultrasonic treatment, etc., and take the supernatant after standing, namely the nano-topological insulator solution;

[0024] S2. Add the nano-topological insulator solution to the organic p-type hole transport material solution to obtain a mixed solution;

[0025] S3. Adopt the solution processing and film-forming method to form a composite film from the mixed solution.

[0026] Optionally, in step S1, the organic solvent is selected from at least one of methanol, ethanol, and isopropanol.

[0027] Optionally, in step S2, the volume of the nano-topological insulator solution accounts for 1% to 50% of the volume of the mixed solution.

[0028] Optionally, in step S2, the percentage of the volume of the nano-topological insulator solution in the volume of the mixed solution is independently selected from any value of 1%, 10%, 20%, 30%, 40%, and 50%.

[0029] Optionally, in step S3, the solution film-forming method includes first solution spin-coating and then low-temperature annealing.

[0030] Optionally, in step S3, the conditions for solution spin-coating are as follows:

[0031] The spin-coating parameter is 500 rpm to 5000 rpm;

[0032] The time for spin coating is 10 s to 120 s.

[0033] Optionally, in step S3, the conditions for low-temperature annealing are as follows:

[0034] The temperature is 50 °C to 150 °C;

[0035] The time is 5 min to 30 min.

[0036] Furthermore, the present invention provides an application of a composite p-type hole transport material.

[0037] The application of the composite p-type hole transport material or the composite p-type hole transport material obtained by the preparation method in an organic solar cell.

[0038] The present invention provides an organic solar cell, which is highly efficient and stable, and its photoelectric conversion efficiency reaches more than 16%.

[0039] An organic solar cell includes a substrate, a bottom electrode, a hole transport layer, an organic photovoltaic active layer, an electron transport layer, and a top electrode;

[0040] The hole transport layer is selected from the composite p-type hole transport material described above or the composite p-type hole transport material obtained by the preparation method described above.

[0041] Even further, the present invention provides a preparation method of an organic solar cell, including the following steps:

[0042] A1. Depositing the bottom electrode on the substrate to obtain a bottom electrode / substrate assembly;

[0043] A2. Spin-coating the hole transport layer onto the surface of the bottom electrode of the bottom electrode / substrate assembly described above, and performing low-temperature annealing to obtain a hole transport layer / bottom electrode / substrate assembly;

[0044] A3. Spin-coat the organic photovoltaic active layer onto the surface of the hole transport layer of the above-mentioned hole transport layer / bottom electrode / substrate assembly, and obtain an organic photovoltaic active layer / hole transport layer / bottom electrode / substrate assembly after low-temperature annealing;

[0045] A4. Spin-coat the electron transport layer onto the surface of the organic photovoltaic active layer of the above-mentioned organic photovoltaic active layer / hole transport layer / bottom electrode / substrate assembly, and obtain an electron transport layer / organic photovoltaic active layer / hole transport layer / bottom electrode / substrate assembly after low-temperature annealing;

[0046] A5. Deposit the top electrode onto the surface of the electron transport layer of the above-mentioned electron transport layer / organic photovoltaic active layer / hole transport layer / bottom electrode / substrate assembly to obtain the organic solar cell.

[0047] Optionally, the substrate is selected from at least one of glass, polyimide, polyethylene terephthalate, polydimethylsiloxane, polyethylene naphthalate, polycarbonate, and polyvinyl alcohol.

[0048] Optionally, the bottom electrode and the top electrode are independently selected from at least one of indium tin oxide, zinc aluminum oxide, fluorine-doped tin oxide, conductive polymer, and metal.

[0049] Optionally, the organic photovoltaic active layer includes a donor material and an acceptor material.

[0050] Optionally, the donor material is selected from at least one of organic polymer semiconductor donor materials and organic small molecule semiconductor donor materials.

[0051] Optionally, the acceptor material is selected from at least one of organic polymer semiconductor acceptor materials, organic small molecule semiconductor acceptor materials, and fullerene derivative acceptor materials.

[0052] More preferably, the organic photovoltaic active layer material is selected from a blend material of an organic polymer semiconductor donor and an organic small molecule semiconductor acceptor.

[0053] Even more preferably, the organic photovoltaic active layer material is selected from a blend material of an organic broadband-gap conjugated polymer semiconductor donor material PM6 and an organic small molecule acceptor material Y6.

[0054] Optionally, the electron transport layer is selected from at least one of n-type metal oxides, polymers, organic small molecule compounds, low work function metals, metal salt complexes, carbon-based materials, and composite materials.

[0055] More preferably, the electron transport layer material is selected from organic small molecule compound materials.

[0056] More preferably, the electron transport layer material uses an organic small molecule compound material: PNDIT-F3N.

[0057] More preferably, the substrate material is glass.

[0058] More preferably, the bottom electrode is indium tin oxide or fluorine-doped tin oxide.

[0059] Preferably, the top electrode material is selected from metal electrode materials.

[0060] More preferably, the top electrode material is silver or aluminum.

[0061] Optionally, in steps A2 - A4, the conditions for spin coating are as follows:

[0062] The spin coating parameter is 500 rpm to 5000 rpm;

[0063] The spin coating time is 10 s to 120 s.

[0064] Optionally, in steps A2 - A4, the conditions for low-temperature annealing are as follows:

[0065] The temperature is 50°C to 150°C;

[0066] The time is 3 min to 30 min.

[0067] The present application provides an application of an organic solar cell.

[0068] The application of the above-mentioned organic solar cell and / or the organic solar cell obtained by the above-mentioned preparation method in the fields of energy and optoelectronics.

[0069] The beneficial effects that the present application can produce are as follows:

[0070] (1) The composite p-type hole transport material provided by the present application has the advantages of high conductivity, high light transmittance, excellent hole transport ability, controllable thickness, high stability, etc.; this material dopes topological insulator nanomaterials into the organic p-type hole transport material thin film. By using its relatively high carrier density and excellent conductivity, the conductivity of PEDOT:PSS can be effectively improved, thereby enhancing the hole transport ability and exciton dissociation efficiency of the device. In addition, the topological insulator nanomaterials can have an electrostatic interaction with PSS, reducing the free sulfonate ions of PEDOT:PSS, thereby reducing the solution acidity, and finally enabling the organic solar cell realized by the present invention to be stable and efficient.

[0071] (2) The preparation method of the composite p-type hole transport material provided by the present application has the advantages of simple preparation process, low cost, and wide universality.

[0072] (3) The organic solar cell provided by this application is highly efficient and stable, with a photoelectric conversion efficiency reaching over 16%, meeting the high performance requirements for potential commercial applications. Description of the Drawings

[0073] Figure 1 It is a schematic diagram of the OSC structure based on the composite p-type hole transport material in Example 1 of the present invention;

[0074] Figure 2 It is a current density-voltage (J-V) characteristic curve graph of the OSCs prepared in Comparative Example 1 and Examples 1-4 of the present invention;

[0075] Figure 3 It is an external quantum efficiency (EQE) spectrum graph of the OSCs prepared in Comparative Example 1 and Examples 1-4 of the present invention;

[0076] Figure 4 It is an atomic force microscope (AFM) test graph of the composite hole transport layer prepared in Example 5 of the present invention. Detailed Embodiments

[0077] Next, the technical solutions in the embodiments of this application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts shall fall within the protection scope of this application.

[0078] Unless otherwise specified, the raw materials in the embodiments of this application are all purchased through commercial channels, among which:

[0079] Glacial acetic acid, poly(3,4-ethylenedioxythiophene): polystyrene sulfonate is purchased from Aladdin Reagent Co., Ltd.;

[0080] Y6, PBDB-T-2F, PNDIT-F3N are purchased from Solarmer Energy Co., Ltd.;

[0081] Indium tin oxide glass is purchased from Shenzhen Huanan Xiangcheng Technology Co., Ltd.

[0082] In the present invention, indium tin oxide is abbreviated as ITO;

[0083] Niobium arsenide is abbreviated as NbAs;

[0084] Organic solar cell is abbreviated as OSC;

[0085] PBDB-T-2F is abbreviated as PM6;

[0086] Poly(3,4-ethylenedioxythiophene): polystyrene sulfonate is abbreviated as PEDOT:PSS.

[0087] The inorganic oxide or organic polymer semiconductor described in the present invention refers to the division according to the carrier transport ability. If the electron transport ability of the semiconductor is "significantly" better than the hole transport ability, this semiconductor is defined as an n-type semiconductor, and vice versa for a p-type semiconductor.

[0088] Example 1

[0089] An inverted device structure is adopted, and the preparation process of the corresponding OSC is as follows:

[0090] (1) A composite p-type hole transport layer is prepared by solution spin coating method and low-temperature annealing process:

[0091] Step 1: Select commercially purchased ITO glass (sheet resistance about 15 Ω / sq) as the substrate, and perform ultraviolet ozone treatment for 15 min before use;

[0092] Step 2: Put the NbAs bulk material into ethanol, ultrasonically crush it for 24 h to decompose it into nano-size, then let it stand for 24 h to precipitate the large NbAs material, and take the supernatant, that is, the uniformly mixed nano-NbAs ethanol solution;

[0093] Step 3: Add the nano-NbAs ethanol solution prepared in Step 2 into PEDOT:PSS, stir for 15 min to mix it evenly, and obtain a composite PEDOT:PSS solution, controlling the volume of the nano-NbAs ethanol solution to account for 10% of the composite PEDOT:PSS solution;

[0094] Step 4: Spin coat the composite PEDOT:PSS solution prepared in Step 3 on the ITO glass treated with ultraviolet ozone, with spin coating parameters of 3000 rpm and spin coating time of 30 s; after spin coating, place the sample on a heating table at 150 °C for annealing treatment for 15 min, so as to finally obtain a hole transport layer / bottom electrode / substrate assembly;

[0095] (2) An organic photovoltaic active layer is prepared by solution spin coating technology:

[0096] Step 1: Weigh the organic polymer semiconductor donor material PM6 and the organic small molecule semiconductor acceptor material Y6 according to a mass ratio of 1:1.2, then add chloroform to prepare a 7.5 mg / ml mixed solution, and stir in a nitrogen atmosphere glove box for 1 h to obtain a uniformly mixed PM6:Y6 organic photovoltaic active layer solution;

[0097] Step 2: Spin-coat the PM6:Y6 organic photovoltaic active layer solution in Step 1 on the surface of the composite p-type hole transport thin film sample in a nitrogen atmosphere glove box. The spin-coating parameters are set to 3000 rpm and the spin-coating time is 30 s. After spin-coating, place the spin-coated sample on a heating table at 100 °C for annealing for 5 min to obtain an organic photovoltaic active layer / hole transport layer / bottom electrode / substrate assembly;

[0098] (3) Prepare the electron transport layer by solution spin-coating technology:

[0099] Step 1: Weigh 1 mg of PNDIT-F3N and dissolve it in 2 mL of methanol, and add 0.5% acetic acid by volume as an additive to dissolve to obtain a clear and uniform electron transport layer material solution;

[0100] Step 2: Spin-coat the electron transport layer material solution in Step 1 on the surface of the organic photovoltaic active layer thin film in a nitrogen atmosphere glove box. The spin-coating parameters are set to 3000 rpm and the spin-coating time is 30 s to obtain an electron transport layer / organic photovoltaic active layer / hole transport layer / bottom electrode / substrate assembly;

[0101] (4) Prepare the metal top electrode by vacuum thermal evaporation:

[0102] Use the conventional vacuum thermal evaporation method and a prefabricated structure mask to prepare a metal electrode on the electron transport layer. The vacuum degree of thermal evaporation is about 1×10 -4 Pa, the current is 30 - 50 A, and the rate is The prepared top electrode is an Ag electrode with an electrode thickness of 100 nm, that is, an organic solar cell is prepared.

[0103] The schematic diagram of the OSC device structure of the prepared ITO / HTL / PM6:Y6 / PNDIT-F3N / Ag structure is as Figure 1 shown.

[0104] Example 2

[0105] Adopt a normal device structure, and the preparation process of its corresponding OSC is as follows:

[0106] (1) Prepare the composite p-type hole transport layer by solution spin-coating method and low-temperature annealing process:

[0107] Step 1: Select commercially purchased ITO glass (sheet resistance about 15 Ω / □) as the substrate, and use ultraviolet ozone treatment for 15 min before use;

[0108] Step 2: Put the NbAs bulk material into ethanol, ultrasonically crush it for 24 h to decompose it into nanoscale, then let it stand for 24 h to precipitate the large NbAs material, and take the supernatant, that is, a uniformly mixed nano-NbAs ethanol solution;

[0109] Step 3: Add the nano-NbAs ethanol solution prepared in Step 2 into PEDOT:PSS, and stir for 15 min to make it evenly mixed, obtaining a composite PEDOT:PSS solution. Control the volume of the nano-NbAs ethanol solution to account for 5% of the composite PEDOT:PSS solution;

[0110] Step 4: Spin-coat the composite PEDOT:PSS solution prepared in Step 3 on the ITO glass treated with ultraviolet ozone. The spin-coating parameters are 3000 rpm and the spin-coating time is 30 s; After spin-coating, place the sample on a heating table at 150 °C for annealing treatment for 15 min, thereby finally obtaining a hole transport layer / bottom electrode / substrate assembly;

[0111] (2) Prepare the organic photovoltaic active layer by solution spin-coating technology:

[0112] Step 1: Weigh the organic polymer semiconductor donor material PM6 and the organic small molecule semiconductor acceptor material Y6 according to a mass ratio of 1:1.2, and then add chloroform to prepare a mixed solution with a concentration of 7.5 mg / ml. Stir in a nitrogen atmosphere glove box for 1 h to obtain a uniformly mixed PM6:Y6 organic photovoltaic active layer solution;

[0113] Step 2: Spin-coat the PM6:Y6 organic photovoltaic active layer solution in Step 1 on the surface of the composite p-type hole transport thin film sample in a nitrogen atmosphere glove box. The spin-coating parameters are set to 3000 rpm and the spin-coating time is 30 s; After spin-coating, place the spin-coated sample on a heating table at 100 °C for annealing for 5 min to obtain an organic photovoltaic active layer / hole transport layer / bottom electrode / substrate assembly;

[0114] (3) Prepare the electron transport layer by solution spin-coating technology:

[0115] Step 1: Weigh 1 mg of PNDIT-F3N and dissolve it in 2 mL of methanol, and add 0.5% acetic acid by volume as an additive to dissolve and obtain a clear and uniform electron transport layer material solution;

[0116] Step 2: Spin-coat the electron transport layer material solution in Step 1 on the surface of the organic photovoltaic active layer thin film in a nitrogen atmosphere glove box. The spin-coating parameters are set to 3000 rpm and the spin-coating time is 30 s to obtain an electron transport layer / organic photovoltaic active layer / hole transport layer / bottom electrode / substrate assembly;

[0117] (4) Prepare the metal top electrode by vacuum thermal evaporation method:

[0118] Use the conventional vacuum thermal evaporation method and a prefabricated structure mask to prepare a metal electrode on the electron transport layer. The vacuum degree of thermal evaporation is about 1×10 -4 Pa, the current is 30 - 50 A, and the rate is The obtained top electrode is an Ag electrode with an electrode thickness of 100 nm, and thus an organic solar cell is fabricated.

[0119] Example 3

[0120] An inverted device structure is adopted, and the preparation process of the corresponding OSC is as follows:

[0121] (1) Prepare a composite p-type hole transport layer by solution spin-coating method and low-temperature annealing process:

[0122] Step 1: Select commercially purchased ITO glass (sheet resistance about 15 Ω / sq) as the substrate, and perform ultraviolet ozone treatment for 15 min before use;

[0123] Step 2: Put the NbAs bulk material into ethanol, ultrasonically crush it for 24 h to decompose it into nanoscale, then let it stand for 24 h to precipitate the large NbAs material, and take the supernatant, that is, the uniformly mixed nano-NbAs ethanol solution;

[0124] Step 3: Add the nano-NbAs ethanol solution prepared in Step 2 into PEDOT:PSS, stir for 15 min to mix evenly, obtain a composite PEDOT:PSS solution, and control the volume of the nano-NbAs ethanol solution to account for 2.5% of the composite PEDOT:PSS solution;

[0125] Step 4: Spin-coat the composite PEDOT:PSS solution prepared in Step 3 on the ITO glass treated with ultraviolet ozone, with the spin-coating parameters of 3000 rpm and the spin-coating time of 30 s; after spin-coating, place the sample on a heating table at 150 °C for annealing treatment for 15 min, so as to finally obtain a hole transport layer / bottom electrode / substrate assembly;

[0126] (2) Prepare an organic photovoltaic active layer by solution spin-coating technology:

[0127] Step 1: Weigh the organic polymer semiconductor donor material PM6 and the organic small molecule semiconductor acceptor material Y6 according to a mass ratio of 1:1.2, and then add chloroform to prepare a mixed solution with a concentration of 7.5 mg / ml, and stir for 1 h in a nitrogen atmosphere glove box to obtain a uniformly mixed PM6:Y6 organic photovoltaic active layer solution;

[0128] Step 2: Spin-coat the PM6:Y6 organic photovoltaic active layer solution in Step 1 on the surface of the composite p-type hole transport thin film sample in a nitrogen atmosphere glove box, with the spin-coating parameters set at 3000 rpm and the spin-coating time of 30 s; after spin-coating, place the spin-coated sample on a heating table at 100 °C for annealing for 5 min to obtain an organic photovoltaic active layer / hole transport layer / bottom electrode / substrate assembly;

[0129] (3) The electron transport layer is prepared by solution spin coating technology:

[0130] Step 1: Weigh 1 mg of PNDIT-F3N and dissolve it in 2 mL of methanol, and add 0.5% acetic acid by volume as an additive to obtain a clear and uniform electron transport layer material solution;

[0131] Step 2: Spin coat the electron transport layer material solution in Step 1 on the surface of the organic photovoltaic active layer film in a nitrogen atmosphere glove box. The spin coating parameters are set to 3000 rpm and the spin coating time is 30 s to obtain an electron transport layer / organic photovoltaic active layer / hole transport layer / bottom electrode / substrate assembly;

[0132] (4) The metal top electrode is prepared by vacuum thermal evaporation:

[0133] Use the conventional vacuum thermal evaporation method and a prefabricated structure mask to prepare a metal electrode on the electron transport layer. The vacuum degree of thermal evaporation is about 1×10 -4 Pa, the current is 30 - 50 A, and the rate is The prepared top electrode is an Ag electrode with an electrode thickness of 100 nm, and thus the organic solar cell is obtained.

[0134] Example 4

[0135] The normal device structure is adopted, and the preparation process of the corresponding OSC is as follows:

[0136] (1) The composite p-type hole transport layer is prepared by solution spin coating method and low-temperature annealing process:

[0137] Step 1: Select commercially purchased ITO glass (sheet resistance about 15 Ω / □) as the substrate, and first treat it with ultraviolet ozone for 15 min before use;

[0138] Step 2: Put the NbAs bulk material into ethanol and ultrasonically crush it for 24 h to decompose it into nanosize, then let it stand for 24 h to precipitate the large NbAs material, and take the supernatant to obtain a uniformly mixed nano-NbAs ethanol solution;

[0139] Step 3: Add the nano-NbAs ethanol solution prepared in Step 2 into PEDOT:PSS, stir for 15 min to make it uniformly mixed to obtain a composite PEDOT:PSS solution, and control the volume of the nano-NbAs ethanol solution to account for 1% of the composite PEDOT:PSS solution;

[0140] Step 4: Spin-coat the composite PEDOT:PSS solution prepared in Step 3 onto the ITO glass treated with ultraviolet ozone. The spin-coating parameters are 3000 rpm and the spin-coating time is 30 s. After spin-coating, place the sample on a heating stage at 150 °C for annealing for 15 min to finally obtain the hole transport layer / bottom electrode / substrate assembly.

[0141] (2) Prepare the organic photovoltaic active layer by solution spin-coating technology:

[0142] Step 1: Weigh the organic polymer semiconductor donor material PM6 and the organic small molecule semiconductor acceptor material Y6 in a mass ratio of 1:1.2, and then add chloroform to prepare a mixed solution with a concentration of 7.5 mg / ml. Stir for 1 h in a glove box under a nitrogen atmosphere to obtain a uniformly mixed PM6:Y6 organic photovoltaic active layer solution.

[0143] Step 2: Spin-coat the PM6:Y6 organic photovoltaic active layer solution in Step 1 onto the surface of the composite p-type hole transport thin film sample in a glove box under a nitrogen atmosphere. The spin-coating parameters are set to 3000 rpm and the spin-coating time is 30 s. After spin-coating, place the spin-coated sample on a heating stage at 100 °C for annealing for 5 min to obtain the organic photovoltaic active layer / hole transport layer / bottom electrode / substrate assembly.

[0144] (3) Prepare the electron transport layer by solution spin-coating technology:

[0145] Step 1: Weigh 1 mg of PNDIT-F3N and dissolve it in 2 mL of methanol, and add 0.5% acetic acid by volume as an additive to dissolve to obtain a clear and uniform electron transport layer material solution.

[0146] Step 2: Spin-coat the electron transport layer material solution in Step 1 onto the surface of the organic photovoltaic active layer thin film in a glove box under a nitrogen atmosphere. The spin-coating parameters are set to 3000 rpm and the spin-coating time is 30 s to obtain the electron transport layer / organic photovoltaic active layer / hole transport layer / bottom electrode / substrate assembly.

[0147] (4) Prepare the metal top electrode by vacuum thermal evaporation:

[0148] Use the conventional vacuum thermal evaporation method and a prefabricated structure mask to prepare a metal electrode on the electron transport layer. The vacuum degree of thermal evaporation is about 1×10 -4 Pa, the current is 30 - 50 A, and the rate is The prepared top electrode is an Ag electrode with an electrode thickness of 100 nm, that is, the organic solar cell is fabricated.

[0149] Comparative Example 1

[0150] Adopt the normal device structure, and the preparation process of its corresponding OSC is as follows:

[0151] (1) The p-type hole transport layer is prepared by the solution spin-coating method and the low-temperature annealing process:

[0152] Step 1: Select commercially purchased ITO glass (sheet resistance about 15 Ω / sq) as the substrate, and perform ultraviolet ozone treatment for 15 min before use;

[0153] Step 2: Spin-coat PEDOT:PSS on the ITO glass treated with ultraviolet ozone. The spin-coating parameters are 3000 rpm and the spin-coating time is 30 s. After spin-coating, anneal the sample on a heating stage at 150 °C for 15 min to finally obtain the hole transport layer / bottom electrode / substrate assembly;

[0154] (2) The organic photovoltaic active layer is prepared by the solution spin-coating technique:

[0155] Step 1: Weigh the organic polymer semiconductor donor material PM6 and the organic small molecule semiconductor acceptor material Y6 in a mass ratio of 1:1.2, and then add chloroform to prepare a mixed solution with a concentration of 7.5 mg / ml. Stir for 1 h in a nitrogen atmosphere glove box to obtain a uniformly mixed PM6:Y6 organic photovoltaic active layer solution;

[0156] Step 2: Spin-coat the PM6:Y6 organic photovoltaic active layer solution in Step 1 on the surface of the composite p-type hole transport thin film sample in a nitrogen atmosphere glove box. The spin-coating parameters are set to 3000 rpm and the spin-coating time is 30 s. After spin-coating, place the spin-coated sample on a heating stage at 100 °C for annealing for 5 min to obtain the organic photovoltaic active layer / hole transport layer / bottom electrode / substrate assembly;

[0157] (3) The electron transport layer is prepared by the solution spin-coating technique:

[0158] Step 1: Weigh 1 mg of PNDIT-F3N and dissolve it in 2 mL of methanol, and add 0.5% acetic acid by volume as an additive to dissolve to obtain a clear and uniform electron transport layer material solution;

[0159] Step 2: Spin-coat the electron transport layer material solution in Step 1 on the surface of the organic photovoltaic active layer thin film in a nitrogen atmosphere glove box. The spin-coating parameters are set to 3000 rpm and the spin-coating time is 30 s to obtain the electron transport layer / organic photovoltaic active layer / hole transport layer / bottom electrode / substrate assembly;

[0160] (4) The metal top electrode is prepared by vacuum thermal evaporation:

[0161] Use the conventional vacuum thermal evaporation method and a prefabricated structure mask to prepare a metal electrode on the electron transport layer. The vacuum degree of thermal evaporation is about 1×10 -4 Pa, the current is 30 - 50 A, and the rate is The obtained top electrode is an Ag electrode with an electrode thickness of 100 nm, and thus an organic solar cell is fabricated.

[0162] Performance testing of the OSC device

[0163] Under the condition of AM 1.5G irradiation, the photovoltaic performance of the organic solar cell was tested by an Oriel Sol3A solar simulator (Newport) and a Keithley2400 semiconductor tester. The J-V characteristic curve of the device sample is as Figure 2 shown, and the EQE spectrum of the device is as Figure 3 shown. Among them, the effective area of the device is 4 mm 2 , the starting voltage of the test is -0.1 V, and the ending voltage is 1.15 V. According to Figure 2 analysis, the open-circuit voltage (V OC ), short-circuit current density (J SC ), fill factor (FF), and power conversion efficiency (PCE) of the measured device are summarized in Table 1. From Figure 3 analysis, it can be seen that the device has a high EQE value in the visible light region, indicating that there is an efficient photo-electric conversion process when the OSC is working. These test results show that the OSC based on the PEDOT:PSS-NbAs composite p-type hole transport layer has good photovoltaic performance.

[0164] Table 1

[0165]

[0166] Example 5

[0167] The preparation process of the composite hole transport layer thin film sample is as follows:

[0168] Step 1: Select commercially purchased ITO glass as the substrate, and perform ultraviolet ozone treatment for 15 min before use;

[0169] Step 2: Put the NbP bulk material into ethanol, ultrasonically crush it for 24 h to decompose it into nano-size, then let it stand for 24 h to precipitate the large NbP material, and take the supernatant, that is, a uniformly mixed nano-NbP ethanol solution;

[0170] Step 3: Add the nano-NbP ethanol solution prepared in Step 2 into PEDOT:PSS, stir for 15 min to mix it evenly, and obtain a composite PEDOT:PSS solution, controlling the volume of the nano-NbP ethanol solution to account for 1% of the composite PEDOT:PSS solution;

[0171] Step 4: Spin-coat the composite PEDOT:PSS solution prepared in Step 3 on the ITO glass treated with ultraviolet ozone. The spin-coating parameters are 3000 rpm and the spin-coating time is 30 s. After spin-coating, place the sample on a heating stage at 150 °C for annealing treatment for 15 min to finally obtain a hole transport layer / bottom electrode / substrate assembly;

[0172] Morphology test of thin film samples

[0173] Perform morphology test on the thin film samples by atomic force microscope. The test results are as Figure 4 shown. In the figure, the brighter granular bright spots are the NbP nanoparticles doped into PEDOT:PSS, with a size of about 20 nm and evenly distributed in the PEDOT:PSS thin film. The surface of PEDOT:PSS-NbP is flat and smooth, and the root mean square (RMS) roughness is 0.864 nm, which is beneficial to form a good ohmic contact with the upper active layer, reduce the contact resistance, and promote the charge collection and transport in the device.

[0174] The above is a specific description of the preferred embodiment of the present invention. However, the present invention is not limited to the described embodiment. Those skilled in the art can make various equivalent deformations or substitutions without departing from the spirit of the present invention, and these equivalent deformations or substitutions are all included in the scope defined by the claims of this application.

Claims

1. An organic solar cell, characterized in that: It includes a substrate, a bottom electrode, a hole transport layer, an organic photovoltaic active layer, an electron transport layer, and a top electrode; The hole transport layer is a composite p-type hole transport material; The composite p-type hole transport material comprises a topological insulator nanomaterial and an organic p-type hole transport material film; The topological insulator nanomaterial is uniformly mixed in the organic p-type hole transport material; The topological insulator nanomaterial is niobium arsenide or niobium phosphide.

2. An organic solar cell according to claim 1, characterized in that: The surface root mean square roughness of the composite p-type hole transport material is 0.5nm to 10nm; the thickness of the composite p-type hole transport material is 5nm to 100nm; and the size of the topological insulator nanomaterial is 5nm to 100nm.

3. An organic solar cell according to claim 1, characterized in that: The organic p-type hole transport material is selected from at least one of poly(3,4-ethylenedioxythiophene): polystyrene sulfonate, polyaniline, polypyrrole, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], and 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene.

4. The organic solar cell according to claim 1, characterized in that: The preparation method of the composite p-type hole transport material comprises the following steps: S1. placing a topological insulator bulk material in an organic solvent, decomposing it into nanometer size by cell crushing or ultrasonic treatment, and taking the supernatant after standing, i.e., the nanotopological insulator solution; S2. adding the nanotopological insulator solution to the organic p-type hole transport material solution to obtain a mixed solution; S3. Using a solution processing film-forming method, the mixed solution is formed into a composite film.

5. An organic solar cell according to claim 4, characterized in that: The organic solvent is selected from at least one of methanol, ethanol and isopropanol; the volume of the nanotopological insulator solution in step S2 accounts for 1% to 50% of the volume of the mixed solution.

6. An organic solar cell according to claim 4, characterized in that: The solution processing film forming method described in step S3 includes first solution spin coating and then low-temperature annealing; the conditions of the solution spin coating are as follows: the spin coating parameters are 500rpm~5000rpm; the coating time is 10s~120s; the conditions of the low-temperature annealing are as follows: the temperature is 50℃~150℃; the time is 5min~30min.

7. A method for preparing an organic solar cell according to any one of claims 1 to 6, characterized in that: include: A1. Depositing the bottom electrode on the substrate to obtain a bottom electrode / substrate assembly; A2. Spin coating the hole transport layer onto the bottom electrode surface of the bottom electrode / substrate assembly, and annealing at low temperature to obtain a hole transport layer / bottom electrode / substrate assembly; A3. Spin coating the organic photovoltaic active layer onto the hole transport layer surface of the hole transport layer / bottom electrode / substrate assembly, and annealing at low temperature to obtain an organic photovoltaic active layer / hole transport layer / bottom electrode / substrate assembly; A4. Spin coating the electron transport layer onto the surface of the organic photovoltaic active layer of the organic photovoltaic active layer / hole transport layer / bottom electrode / substrate assembly, and annealing at low temperature to obtain the electron transport layer / organic photovoltaic active layer / hole transport layer / bottom electrode / substrate assembly; A5. Depositing the top electrode onto the surface of the electron transport layer of the electron transport layer / organic photovoltaic active layer / hole transport layer / bottom electrode / substrate assembly to obtain the organic solar cell.

8. The method for preparing an organic solar cell according to claim 7, characterized in that: The substrate is selected from at least one of glass, polyimide, polyethylene terephthalate, polydimethylsiloxane, polyethylene naphthalate, polycarbonate, and polyvinyl alcohol; the bottom electrode and the top electrode are independently selected from at least one of indium tin oxide, zinc aluminum oxide, fluorine-doped tin oxide, conductive polymers, and metals; the organic photovoltaic active layer includes a donor material and an acceptor material; the donor material is selected from at least one of an organic polymer semiconductor donor material and an organic small molecule semiconductor donor material; the acceptor material is selected from at least one of an organic polymer semiconductor acceptor material, an organic small molecule semiconductor acceptor material, and a fullerene derivative acceptor material; the electron transport layer is selected from at least one of n-type metal oxides, polymers, organic small molecule compounds, low work function metals, metal salt complexes, carbon-based materials, and composite materials.

9. The method for preparing an organic solar cell according to claim 7, characterized in that: In steps A2-A4, the spin coating conditions are as follows: the spin coating parameters are 500rpm to 5000rpm; the coating time is 10s to 120s; the low-temperature annealing conditions are as follows: the temperature is 50°C to 150°C; the time is 3min to 30min.

10. Application of the organic solar cell according to any one of claims 1 to 6 or the organic solar cell prepared by the preparation method according to any one of claims 7 to 9 in the fields of energy and optoelectronics.

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