An efficient and stable quasi-planar organic solar cell and its preparation method

Abstract

This application relates to the technical field of organic solar cells, and discloses a highly efficient and stable quasi-planar organic solar cell and a preparation method thereof. The highly efficient and stable quasi-planar organic solar cell includes, from bottom to top, a transparent conductive substrate, a hole transport layer, an active layer, an electron transport layer, and a metal cathode layer; the active layer includes a polymer donor layer containing a hindered phenol antioxidant spin-coated on the hole transport layer, and a non-fullerene acceptor layer containing an additive spin-coated on the polymer donor layer. This application adopts a strategy combining the use of a hindered phenol antioxidant as an additive with a continuous spin-coating method to obtain an active layer with high intrinsic stability and morphological stability, and further obtain an organic solar cell with high stability and high optoelectronic performance. The organic solar cell prepared in this application has its efficiency significantly increased to 19.03%, and has excellent stability, showing good commercial prospects.

Description

Technical Field

[0001] The present application relates to the technical field of organic solar cells, and in particular to a highly efficient and stable quasi-planar organic solar cell and a preparation method thereof. Background Art

[0002] As a new photovoltaic technology, organic solar cells are attracting increasing attention due to their advantages, including low cost, lightweight, flexibility, solvent processability, and large-area printing. Researchers are making continuous progress in understanding the mechanisms of organic solar cells, designing and synthesizing active layer materials, and controlling their morphology. Single-junction organic solar cells have achieved energy conversion efficiencies exceeding 19%.

[0003] Continuous breakthroughs in device efficiency have greatly increased the commercial potential of organic solar cells. However, device stability remains crucial to their future commercial viability. Generally speaking, the stability of the active layer plays a decisive role in the lifespan of organic solar cells and is primarily influenced by two factors. First, the active layer material exhibits poor inherent stability under conditions such as light, heat, water, and oxygen. Some studies have shown that high-energy ultraviolet light can induce polymer molecules to react with oxygen to produce superoxide radicals, or energy can be transferred from the polymer's triplet excitons to molecular oxygen, forming singlet oxygen. When electrons transfer from a donor to an acceptor, if the acceptor's lowest unoccupied molecular orbital energy level is relatively shallow, the electrons are more likely to react with oxygen to form superoxide anions. The reactive species generated in the active layer, such as superoxide radicals, singlet oxygen, and superoxide anions, can irreversibly decompose the donor and acceptor molecules, particularly initiating chain scission reactions in the polymer donor, leading to donor degradation and significant degradation of device performance. Furthermore, in active layer systems based on polymer donors and Y6-type acceptors, the polymer donor exhibits significantly poorer photostability and is more susceptible to photobleaching under illumination. Currently, UV filters, UV absorbers, or antioxidants are commonly used to inhibit photoaging and improve device stability. However, these methods typically only bring minimal performance improvements or even require a certain degree of sacrifice in device performance.

[0004] On the other hand, the morphological stability of the active layer is also insufficient. High-efficiency bulk heterojunction (BHJ) devices are usually formed by mixing electron donor and acceptor materials, and their morphology is often in a non-thermodynamic equilibrium state. Due to the different glass transition temperatures of the donor and acceptor, their diffusion coefficients are also different. Therefore, under light or heat conditions, the donor and acceptor tend to re-aggregate, forming excessive phase separation, namely the "island effect", which significantly reduces the exciton dissociation and charge collection efficiency, and ultimately reduces the stability of the device.

[0005] Currently, methods for improving the stability of the active layer include forming a quasi-planar heterojunction (PPHJ) morphology through the sequential deposition of donors and acceptors, or developing an all-polymer active layer to reduce entropy and improve morphological stability. Although these studies have improved morphological stability to a certain extent, research on simultaneously improving the intrinsic stability and morphological stability of the active layer remains relatively limited, making it difficult to simultaneously improve device stability and optoelectronic performance. Summary of the Invention

[0006] The present application provides a highly efficient and stable quasi-planar organic solar cell and a preparation method thereof, aiming to solve the problem that the active layer of existing organic solar cells is difficult to achieve both intrinsic stability and morphological stability, resulting in the organic solar cell being difficult to achieve both high stability and high photoelectric performance.

[0007] In order to achieve the above objectives, this application adopts the following technical solutions.

[0008] In a first aspect of the present application, a highly efficient and stable quasi-planar organic solar cell is provided, which comprises, from bottom to top, a transparent conductive substrate, a hole transport layer, an active layer, an electron transport layer, and a metal cathode layer;

[0009] The active layer comprises a polymer donor layer with a hindered phenol antioxidant added thereto and which is spin-coated on a hole transport layer, and a non-fullerene acceptor layer containing an additive and which is spin-coated on the polymer donor layer.

[0010] Preferably, the polymer donor is any one of PM6, PM7 or D18;

[0011] The non-fullerene acceptor is BTP-eC9 or L8-BO;

[0012] The hindered phenol antioxidant is any one of antioxidants AO1010, AO245 or AO3114;

[0013] The additive is 1,8-diiodooctane or 1,3-dibromo-5-chlorobenzene.

[0014] Preferably, the amount of the hindered phenol antioxidant is 2-8 wt% of the amount of the polymer donor.

[0015] Preferably, the thickness of the active layer is 100-150 nm.

[0016] Preferably, the transparent conductive substrate is ITO glass;

[0017] The hole transport layer material is 2PACz;

[0018] The metal cathode layer material is Ag or Al;

[0019] When the non-fullerene acceptor is BTP-eC9, the electron transport layer material is PFN-Br and the additive is 1,8-diiodooctane;

[0020] When the non-fullerene acceptor is L8-BO, the electron transport layer material is PDINN and the additive is 1,3-dibromo-5-chlorobenzene.

[0021] In a second aspect of the present application, there is provided a method for preparing the above-mentioned highly efficient and stable quasi-planar organic solar cell, including:

[0022] S1, after cleaning the transparent conductive substrate, spin-coating an ethanol solution with a concentration of 2PACz on its surface, and forming a hole transport layer through annealing treatment;

[0023] S2, dissolving the polymer donor and the hindered phenol antioxidant in chloroform to prepare a donor solution;

[0024] Dissolve BTP-eC9 and 1,8-diiodooctane in chloroform to prepare acceptor solution A. First, spin-coat the donor solution on the surface of the hole transport layer, and then spin-coat acceptor solution A on the surface of the hole transport layer. After annealing treatment, an active layer A is obtained;

[0025] Or,

[0026] Dissolve L8-BO and 1,3-dibromo-5-chlorobenzene in chloroform to prepare acceptor solution B. First, spin-coat the donor solution on the surface of the hole transport layer, and then spin-coat acceptor solution B on the surface of the hole transport layer. After annealing treatment, an active layer B is obtained;

[0027] S3, dissolve PFN-Br in methanol to prepare electron transport material solution A, and spin-coat this solution on the surface of active layer A to form an electron transport layer;

[0028] Or, dissolve PDINN in methanol to prepare electron transport material solution B, and spin-coat this solution on the surface of active layer B to form an electron transport layer;

[0029] S4, evaporate and deposit a metal conductor on the surface of the electron transport layer to form a metal cathode layer, thereby obtaining a quasi-planar organic solar cell.

[0030] Preferably, in S2, the rotation speed of spin-coating the donor solution is 2000 - 2500 rpm, and the spin-coating time is 30 - 40 s;

[0031] The rotation speed of acceptor solution A or acceptor solution B is 1500 - 2000 rpm, and the spin-coating time is 30 - 40 s;

[0032] The annealing temperature is 90 - 100 °C, and the annealing time is 5 - 10 min.

[0033] Preferably, the rotation speed of the spin coating of the 2PACz ethanol solution in S1 is 3000 rpm, and the spin coating time is 30 s; the annealing temperature is 80 - 90 °C, and the time is 3 - 5 min;

[0034] In S3, the rotation speed of the spin coating of the electron transport material solution A or the electron transport material solution B is 3000 - 3500 rpm, and the spin coating time is 30 - 40 s.

[0035] Preferably, the concentration of the 2PACz ethanol solution is 0.1 - 1.0 mg / mL;

[0036] In the donor solution, the total concentration of the polymer donor and the hindered phenol antioxidant is 6 - 10 mg / mL;

[0037] In the acceptor solution A, the concentration of BTP-eC9 is 6 - 12 mg / mL;

[0038] In the acceptor solution B, the concentration of L8-BO is 8 - 12 mg / mL;

[0039] In the electron transport material solution A, the concentration of PFN-Br is 0.1 - 1.0 mg / mL;

[0040] In the electron transport material solution B, the concentration of PDINN is 0.1 - 1.0 mg / mL;

[0041] Preferably, the volume of 1,8-diiodooctane is 0.25 - 0.5% of the volume of the acceptor solution A;

[0042] In the acceptor solution B, the concentration of 1,3-dibromo-5-chlorobenzene is 10 - 15 mg / mL.

[0043] Compared with the prior art, the beneficial effects of this application are:

[0044] This application adopts a strategy that combines hindered phenol antioxidants as additives with a continuous spin-coating method to obtain an active layer with high intrinsic stability and morphological stability, and further obtains a quasi-planar organic solar cell with high stability and excellent optoelectronic performance. On the one hand, hindered phenol antioxidants have multiple hydroxyl binding sites and can react highly with superoxide radicals, thereby quenching free radicals and terminating the free-radical-induced chain degradation reaction, thus improving the intrinsic stability of the material. On the other hand, hindered phenol antioxidants have excellent thermal stability and obvious steric hindrance effects, which can prevent excessive aggregation of donor and acceptor materials, thereby improving morphological stability. In addition, hindered phenol antioxidants have a synergistic effect with the common donor PM6. Multiple hydroxyl groups in hindered phenol antioxidants are prone to form hydrogen bonds with fluorine atoms in the donor PM6, thereby enhancing the intermolecular interaction, increasing the crystallinity of PM6, making the molecular packing more orderly, improving the vertical phase separation morphology, and being beneficial to charge separation and transport.

[0045] The quasi-planar organic solar cell prepared in this application has an efficiency significantly increased to 19.03% and excellent stability, showing good commercial prospects. Brief Description of the Drawings

[0046] In order to more clearly illustrate the technical solutions of the embodiments of this application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0047] Figure 1 It is the ultraviolet-visible light absorption spectrogram of the polymer donor PM6, non-fullerene acceptor BTP-eC9 and L8-BO, and antioxidant AO1010;

[0048] Figure 2 It is the current-voltage curve diagram of the quasi-planar organic solar cells of Example 2 and Comparative Example 1;

[0049] Figure 3 It is the current-voltage curve diagram of the quasi-planar organic solar cells of Example 4 and Comparative Example 2;

[0050] Figure 4 It is the energy conversion efficiency normalization diagram of the quasi-planar organic solar cells of Example 4 and Comparative Example 2. Detailed Description of the Embodiments

[0051] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the protection scope of the present application.

[0052] In the following description of this embodiment, the terms "include", "comprise", "have" and "contain" are all open-ended terms, that is, they are meant to include but not limited to.

[0053] In the following description of this embodiment, the term "and / or" is used to describe the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, B exists alone, and both A and B exist simultaneously. Where A and B can be singular or plural. The character " / " generally indicates that the associated objects before and after are an "or" relationship.

[0054] In the following description of this embodiment, the term "at least one" means one or more, and "a plurality" means two or more. "At least one of the following items" or its similar expressions refer to any combination of these items, including any combination of single item or plural items. For example, "at least one of a, b or c", or, "at least one of a, b and c" can all mean: a, b, c, a - b (that is, a and b), a - c, b - c, or a - b - c, where a, b, c can be single or plural respectively.

[0055] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms of "a" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0056] Those skilled in the art should understand that in the following description of the embodiments of the present application, the sequence numbers do not mean the order of execution, and some or all steps can be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0057] Those skilled in the art should understand that the numerical ranges in the embodiments of the present application should be understood as specifically disclosing each intermediate value between the upper and lower limits of the range. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present application. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0058] Unless otherwise specified, the technical / scientific terms used herein have the same meanings as commonly understood by those of ordinary skill in the art to which this application pertains. Although this application only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of this application. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the said documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0059] In a first aspect, this application provides a highly efficient and stable quasi-planar organic solar cell, which includes a transparent conductive substrate, a hole transport layer, an active layer, an electron transport layer, and a metal cathode layer from bottom to top;

[0060] The active layer includes a polymer donor layer added with a hindered phenol antioxidant spin-coated on the hole transport layer, and a non-fullerene acceptor layer containing an additive spin-coated on the polymer donor layer.

[0061] In this application, the polymer donor is any one of PM6, PM7, or D18; the non-fullerene acceptor is BTP-eC9 or L8-BO; the hindered phenol antioxidant is any one of antioxidant AO1010, AO245, or AO3114. Preferably AO1010. Among them, the polymer donor is preferably PM6, and the hindered phenol antioxidant is preferably AO1010. Specifically, the chemical structures of PM6, BTP-eC9, L8-BO, and AO1010 are shown as follows:

[0062]

[0063] In this application, by adding a hindered phenol antioxidant to the polymer donor and adding 1,8-diiodooctane or 1,3-dibromo-5-chlorobenzene to the non-fullerene acceptor, an active layer with a thickness of 100 - 150 nm, high intrinsic stability, and morphological stability is formed, thereby improving the stability and optoelectronic performance of the organic solar cell, and obtaining a highly efficient and stable quasi-planar organic solar cell.

[0064] Among them, the dosage of the preferred hindered phenol antioxidant is 2 - 8 wt% of the dosage of the polymer donor. The hindered phenol antioxidant AO1010 has multiple hydroxyl binding sites, can react highly with superoxide radicals, thereby quenching free radicals and terminating the free radical-induced chain degradation reaction, thus improving the intrinsic stability of the active layer material. In addition, due to the excellent thermal stability and obvious steric hindrance effect of the hindered phenol antioxidant AO1010, it can effectively prevent the excessive aggregation of donor and acceptor materials, thereby improving the morphological stability.

[0065] In addition, multiple hydroxyl groups in the hindered phenol antioxidant AO1010 can easily form hydrogen bonds with fluorine atoms in the common donor PM6, thereby enhancing the intermolecular interaction, increasing the crystallinity of PM6, making the molecular packing more orderly, improving the vertical phase separation morphology, and being beneficial to charge separation and transport.

[0066] In this application, the transparent conductive substrate is preferably ITO glass; the hole transport layer material is preferably 2PACz; the metal cathode layer material is preferably Ag or Al.

[0067] In this application, in order to achieve better technical effects, the non-fullerene acceptor and the electron layer transport material are adapted. When the non-fullerene acceptor is BTP-eC9, the electron transport layer material is PFN-Br, and the additive is 1,8-diiodooctane; when the non-fullerene acceptor is L8-BO, the electron transport layer material is PDINN, and the additive is 1,3-dibromo-5-chlorobenzene.

[0068] In the second aspect, this application provides a method for preparing the above-mentioned highly efficient and stable quasi-planar organic solar cell, including:

[0069] S1, after cleaning the transparent conductive substrate, spin-coat an ethanol solution with a concentration of 2PACz on its surface, and form a hole transport layer through annealing treatment;

[0070] Specifically, for the transparent conductive substrate, such as ITO glass, ultrasonically clean it successively with a detergent aqueous solution, acetone and isopropanol, and then treat it with a plasma cleaner.

[0071] Dissolve 2PACz in ethanol to prepare a solution with a concentration of 0.1 - 1.0 mg / mL; spin-coat this solution on the surface of the cleaned ITO glass at a speed of 3000 rpm for 30 s; then raise the temperature to 80 - 90 °C and keep it warm for 3 - 5 min for annealing.

[0072] S2, dissolve the polymer donor and the hindered phenol antioxidant in chloroform to prepare a donor solution. Among them, in the donor solution, preferably the dosage of the hindered phenol antioxidant is 2 - 8 wt% of the dosage of the polymer donor, and the total concentration of the polymer donor and the hindered phenol antioxidant is 6 - 10 mg / mL. Then, according to the selected non-fullerene acceptor material, adapt different additives, prepare a receptor solution, and then prepare an active layer.

[0073] In the examples of this application, two different non-fullerene acceptor materials were selected to prepare two active layers, denoted as active layer A and active layer B respectively.

[0074] Specifically, when the non-fullerene acceptor material is BTP-eC9, BTP-eC9 and 1,8-diiodooctane are dissolved in chloroform to prepare acceptor solution A. First, the donor solution is spin-coated on the surface of the hole transport layer, and then the acceptor solution A is spin-coated on the surface of the hole transport layer. After annealing treatment, the active layer A is obtained. Among them, the concentration of BTP-eC9 in the acceptor solution A is 6-12 mg / mL, and the volume of 1,8-diiodooctane is 0.25-0.5% of the volume of the acceptor solution A.

[0075] When the non-fullerene acceptor material is L8-BO, L8-BO and 1,3-dibromo-5-chlorobenzene are dissolved in chloroform to prepare acceptor solution B. First, the donor solution is spin-coated on the surface of the hole transport layer, and then the acceptor solution B is spin-coated on the surface of the hole transport layer. After annealing treatment, the active layer B is obtained. Among them, in the acceptor solution B, the concentration of L8-BO is 8-12 mg / mL, and the concentration of 1,3-dibromo-5-chlorobenzene is 10-15 mg / mL.

[0076] Among them, the spin-coating speed of the donor solution is 2000-2500 rpm, and the spin-coating time is 30-40 s; the rotation speed of the acceptor solution A or the acceptor solution B is 1500-2000 rpm, and the spin-coating time is 30-40 s; after the spin-coating of the acceptor solution A or the acceptor solution B, the device is heated to 90-100 °C and kept warm for 5-10 min for annealing.

[0077] S3, PFN-Br is dissolved in methanol to prepare the electron transport material solution A, and this solution is spin-coated on the surface of the active layer A to form the electron transport layer;

[0078] Specifically, when the non-fullerene acceptor material is BTP-eC9, for the electron transport layer corresponding to the prepared active layer A, the electron transport material is PFN-Br, and the concentration of PFN-Br is 0.1-1.0 mg / mL.

[0079] Or,

[0080] PDINN is dissolved in methanol to prepare the electron transport material solution B, and this solution is spin-coated on the surface of the active layer B to form the electron transport layer;

[0081] Specifically, when the non-fullerene acceptor material is L8-BO, for the electron transport layer corresponding to the prepared active layer B, the electron transport material is PDINN, and the concentration of PDINN is 0.1-1.0 mg / mL.

[0082] Among them, the spin-coating speed of the electron transport material solution A or the electron transport material solution B is 3000-3500 rpm, and the spin-coating time is 30-40 s.

[0083] S4. Evaporate and deposit a metal conductor on the surface of the electron transport layer to form a metal cathode layer, thereby obtaining a quasi-planar organic solar cell.

[0084] In this application, the metal of the cathode layer is preferably silver or aluminum.

[0085] This application adopts a strategy of combining a hindered phenol antioxidant as an additive with a continuous spin-coating method to obtain an active layer with high intrinsic stability and morphological stability, improving the stability and optoelectronic performance of the organic solar cell, and further obtaining a quasi-planar organic solar cell with high stability and high optoelectronic performance. Its photoelectric conversion efficiency reaches 19.03%, and it has excellent stability, showing good commercialization prospects.

[0086] The following further illustrates this application through examples.

[0087] Example 1

[0088] This example provides a preparation method of a quasi-planar organic solar cell, including:

[0089] S1. Sequentially ultrasonic clean the ITO conductive glass sheet in detergent solution, acetone, and isopropanol for 40 minutes each, dry it with a nitrogen gun, and then perform plasma cleaning for 3 minutes;

[0090] Transfer the cleaned ITO glass sheet to a glove box, spin-coat an ethanol solution of 2PACz with a concentration of 0.5 mg / mL on the ITO glass sheet at a rotation speed of 3000 rpm for 30 seconds; then anneal at 80 °C for 3 minutes to form a hole transport layer;

[0091] S2. Dissolve PM6 and AO1010 in chloroform to prepare a donor solution with a concentration of 8 mg / mL, where the dosage of AO1010 is 3 wt% of the dosage of PM6; dissolve BTP-eC9 with 1,8-diiodooctane with a volume ratio of 0.25% in chloroform to prepare a receptor solution with a concentration of 9 mg / mL;

[0092] Spin-coat the donor solution on the surface of the hole transport layer at a rotation speed of 2500 rpm for 30 seconds; then spin-coat the receptor solution at a rotation speed of 2000 rpm for 30 seconds. The obtained mixed film has a thickness of about 110 nm to form a quasi-planar heterojunction thin film, namely the active layer; anneal the device at 100 °C for 5 minutes.

[0093] S3. Dissolve PFN-Br in methanol to prepare a solution with a concentration of 0.5 mg / ml, and then spin-coat this solution on the active layer at a spin-coating speed of 3000 rpm for 30 seconds to form an electron transport layer.

[0094] S4. Deposit a metallic Ag cathode layer on the electron transport layer to obtain a quasi-planar organic solar cell.

[0095] Example 2

[0096] This example provides a method for preparing a quasi-planar organic solar cell, including:

[0097] S1. Pass the ITO conductive glass sheet through detergent solution, acetone, and isopropanol successively for ultrasonic cleaning for 40 minutes each, dry it with a nitrogen gun, and then perform plasma cleaning for 3 minutes;

[0098] Transfer the cleaned ITO glass sheet to a glove box, spin-coat an ethanol solution of 2PACz with a concentration of 0.5 mg / mL on the ITO glass sheet at a rotation speed of 3000 rpm for 30 s; then anneal it at 80 °C for 3 minutes to form a hole transport layer;

[0099] S2. Dissolve PM6 and AO1010 in chloroform to prepare a donor solution with a concentration of 8 mg / mL, where the dosage of AO1010 is 5 wt% of the dosage of PM6; dissolve BTP-eC9 with 1,8-diiodooctane added at a volume ratio of 0.25% in chloroform to prepare a receptor solution with a concentration of 9 mg / mL;

[0100] Spin-coat the donor solution on the surface of the hole transport layer at a rotation speed of 2500 rpm for 30 s; then spin-coat the receptor solution at a rotation speed of 2000 rpm for 30 s. The obtained mixed film has a thickness of about 110 nm to form a quasi-planar heterojunction thin film, i.e., the active layer; anneal the device at 100 °C for 5 minutes.

[0101] S3. Dissolve PFN-Br in methanol to prepare a solution with a concentration of 0.5 mg / ml, and then spin-coat this solution on the active layer at a spin-coating speed of 3000 rpm for 30 s to form an electron transport layer.

[0102] S4. Deposit a metallic Ag cathode layer on the electron transport layer to obtain a quasi-planar organic solar cell.

[0103] Example 3

[0104] This example provides a method for preparing a quasi-planar organic solar cell, including:

[0105] S1. Pass the ITO conductive glass sheet through detergent solution, acetone, and isopropanol successively for ultrasonic cleaning for 40 minutes each, dry it with a nitrogen gun, and then perform plasma cleaning for 3 minutes;

[0106] The cleaned ITO glass slide was transferred to a glove box and a 0.5 mg / mL 2PACz ethanol solution was spin-coated on the ITO glass slide at a speed of 3000 rpm for 30 seconds. The slide was then annealed at 80°C for 3 minutes to form a hole transport layer.

[0107] S2, PM6 and AO1010 were dissolved in chloroform to prepare a donor solution with a concentration of 8 mg / mL, wherein the amount of AO1010 was 8 wt% of the amount of PM6; BTP-eC9 to which 0.25% by volume of 1,8-diiodooctane was added was dissolved in chloroform to prepare an acceptor solution with a concentration of 9 mg / mL;

[0108] The donor solution was spin-coated on the surface of the hole transport layer at a speed of 2500 rpm for 30 seconds; then the acceptor solution was spin-coated at a speed of 2000 rpm for 30 seconds. The resulting mixed film thickness was about 110 nm, forming a quasi-planar heterojunction film, i.e., the active layer; the device was annealed at 100°C for 5 minutes.

[0109] S3, dissolving PFN-Br in methanol to prepare a solution with a concentration of 0.5 mg / ml, and then spin-coating the solution on the active layer at a spin-coating speed of 3000 rpm for 30 seconds to form an electron transport layer.

[0110] S4, evaporating a metal Ag cathode layer on the electron transport layer to obtain a quasi-planar organic solar cell.

[0111] Example 4

[0112] This embodiment provides a method for preparing a quasi-planar organic solar cell, comprising:

[0113] S1, the ITO conductive glass sheet was sequentially subjected to ultrasonic cleaning of detergent solution, acetone and isopropyl alcohol for 40 min each, blown dry with a nitrogen gun, and then subjected to plasma cleaning for 3 min;

[0114] The cleaned ITO glass slide was transferred to a glove box and a 0.5 mg / mL 2PACz ethanol solution was spin-coated on the ITO glass slide at a speed of 3000 rpm for 30 seconds. The slide was then annealed at 80°C for 3 minutes to form a hole transport layer.

[0115] S2, dissolving PM6 and AO1010 in chloroform to prepare a donor solution with a concentration of 8 mg / mL, wherein the amount of AO1010 is 5 wt% of the amount of PM6; dissolving 1,3-dibromo-5-chlorobenzene and L8-BO in chloroform to prepare an acceptor solution with a concentration of 12 mg / mL of 1,3-dibromo-5-chlorobenzene and a concentration of 10 mg / mL of L8-BO;

[0116] Spin-coat the donor solution on the surface of the hole transport layer at a speed of 2500 rpm for 30 s; then spin-coat the acceptor solution at a speed of 2000 rpm for 30 s. The resulting mixed film has a thickness of about 110 nm, forming a quasi-planar heterojunction thin film, i.e., the active layer; anneal the device at 100 °C for 5 min.

[0117] S3. Dissolve PDINN in methanol to prepare a solution with a concentration of 1.5 mg / ml, and then spin-coat this solution on the active layer at a spin-coating speed of 3000 rpm for 30 s to form an electron transport layer.

[0118] S4. Evaporate a metal Ag cathode layer on the electron transport layer to obtain a quasi-planar organic solar cell.

[0119] Comparative Example 1

[0120] The difference between Comparative Example 1 and Example 1 is that AO1010 is not added to the donor solution, and the rest are the same as in Example 1.

[0121] Comparative Example 2

[0122] The difference between Comparative Example 2 and Example 4 is that AO1010 is not added to the donor solution, and the rest are the same as in Example 4.

[0123] Test the ultraviolet-visible absorption spectra of the polymer donor PM6, non-fullerene acceptor BTP-eC9, L8-BO and antioxidant AO1010 used in the active layer of the example, and the results are as Figure 1 shown. As can be seen from Figure 1 , AO1010 does not absorb sunlight, while the donor PM6 and the acceptor BTP-eC9 or L8-BO have good complementary absorption.

[0124] Test the optoelectronic properties of the quasi-planar organic solar cell devices prepared in Examples 1-4 and Comparative Examples 1-2. The specific method is as follows:

[0125] Select a light source of AM1.5G, and the sunlight intensity is 100 mW / cm 2 of simulated sunlight. Among them, the intensity of the light source is tested and corrected by a standard silicon cell, and the test instrument is a Keithley 2400 Source Meter type tester. Test the optoelectronic properties of the above organic solar cells, including open-circuit voltage (V OC ), short-circuit current (J SC ), fill factor (FF) and power conversion efficiency (PCE), where: PCE = V OC * J SC * FF / Pin (Pin is the illumination intensity of the incident light).

[0126] Among them, for the binary and ternary quasi-planar organic solar cells based on PM6 / BTP-eC9, such as the current-voltage curves of the organic solar cells in Example 2 and Comparative Example 1 under illumination are as Figure 2 shown. The current density of Example 2 is higher than that of Comparative Example 1; for the binary and ternary quasi-planar organic solar cells based on PM6 / L8-BO, such as the current-voltage curves of the organic solar cells in Example 4 and Comparative Example 2 under illumination are as Figure 3 shown. The current density of Example 4 is higher than that of Comparative Example 2. For the quasi-planar organic solar cells prepared by introducing hindered phenol antioxidants in this application, their optoelectronic properties have been improved.

[0127] The test results of the quasi-planar organic solar cells prepared in Examples 1-4 and Comparative Examples 1-2 are shown in Table 1.

[0128] Table 1 Optoelectronic performance parameters of different devices under AM1.5G, 100mW / cm 2 illumination

[0129]

[0130]

[0131] It can be seen from the test results in Table 1 that when the antioxidant is added as an additive to PM6, the short-circuit current and fill factor of the obtained ternary quasi-planar organic solar cells are both improved compared with those of the binary system quasi-planar organic solar cells, indicating that the exciton dissociation and charge transport efficiency are improved and the charge recombination is inhibited. When AO1010 accounts for 5% of the donor mass, the effect of the prepared quasi-planar organic solar cells reaches the best. Among them, when 5wt% of AO1010 is added to PM6 / L8-BO, the energy conversion efficiency can reach 19.03%, which is much higher than 18.02% of its binary system.

[0132] The storage stability test was carried out on the quasi-planar organic solar cells prepared in Example 4 and Comparative Example 4. The specific method is as follows:

[0133] Under 25°C and nitrogen atmosphere, the energy conversion efficiency of the quasi-planar device was measured every 100h through a standard solar simulator, and the obtained energy conversion efficiency was plotted by normalization, as Figure 4 shown.

[0134] From Figure 4It can be seen that after adding A01010, the storage stability of the device is significantly improved. The extrapolated T80 life of the device based on PM6+AO1010(5%) / L8-BO in Example 4 exceeds 3000 hours, which is significantly better than that of the device in Comparative Example 2 without AO1010, indicating that the addition of this antioxidant greatly improves the efficiency of the device and effectively improves the device stability.

[0135] Although this application has been described in detail in this specification with general descriptions and specific embodiments, some modifications or improvements can be made based on this application, which are obvious to those skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of this application fall within the scope of protection required by this application.

Claims

1. An efficient and stable quasi-planar organic solar cell, characterized in that, It includes, from bottom to top, a transparent conductive substrate, a hole transport layer, an active layer, an electron transport layer, and a metal cathode layer; The active layer includes a polymer donor layer doped with a hindered phenol antioxidant spin-coated on the hole transport layer, and a non-fullerene acceptor layer containing an additive spin-coated on the polymer donor layer; The polymer donor is PM6; The non-fullerene acceptor is BTP-eC9 or L8-BO; The hindered phenol antioxidant is antioxidant AO1010; The additive is 1,8-diiodooctane or 1,3-dibromo-5-chlorobenzene.

2. The highly efficient and stable quasi-planar organic solar cell according to claim 1, wherein The dosage of the hindered phenol antioxidant is 2-8 wt% of the polymer donor dosage.

3. The highly efficient and stable quasi-planar organic solar cell according to claim 1, wherein The thickness of the active layer is 100-150 nm.

4. The highly efficient and stable quasi-planar organic solar cell according to claim 1, characterized in that, The transparent conductive substrate is ITO glass; The hole transport layer material is 2PACz; The metal cathode layer material is Ag or Al; When the non-fullerene acceptor is BTP-eC9, the electron transport layer material is PFN-Br, and the additive is 1,8-diiodooctane; When the non-fullerene acceptor is L8-BO, the electron transport layer material is PDINN, and the additive is 1,3-dibromo-5-chlorobenzene.

5. The preparation method of the highly efficient and stable quasi-planar organic solar cell according to claim 4, characterized in that, It includes: S1. After cleaning the transparent conductive substrate, spin-coat an ethanol solution of 2PACz on its surface, and form a hole transport layer through annealing treatment; S2. Dissolve the polymer donor and the hindered phenol antioxidant in chloroform to prepare a donor solution; Dissolve BTP-eC9 and 1,8-diiodooctane in chloroform to prepare a receptor solution A. First, spin-coat the donor solution on the surface of the hole transport layer, and then spin-coat the receptor solution A on the surface of the hole transport layer, and obtain an active layer A through annealing treatment; Or, Dissolve L8-BO and 1,3-dibromo-5-chlorobenzene in chloroform to prepare a receptor solution B. First, spin-coat the donor solution on the surface of the hole transport layer, and then spin-coat the receptor solution B on the surface of the hole transport layer, and obtain an active layer B through annealing treatment; S3. Dissolve PFN-Br in methanol to prepare an electron transport material solution A, and spin-coat this solution on the surface of the active layer A to form an electron transport layer; Or, dissolve PDINN in methanol to prepare an electron transport material solution B, and spin-coat this solution on the surface of the active layer B to form an electron transport layer; S4. Evaporate and deposit a metal conductor on the surface of the electron transport layer to form a metal cathode layer, and obtain a quasi-planar organic solar cell.

6. The preparation method according to claim 5, characterized in that, In S2, the spinning speed of the donor solution is 2000-2500 rpm, and the spinning time is 30-40 s; The spinning speed of the receptor solution A or the receptor solution B is 1500-2000 rpm, and the spinning time is 30-40 s; The annealing temperature is 90-100 °C, and the annealing time is 5-10 min.

7. The preparation method according to claim 5, characterized in that, In S1, the spinning speed of the ethanol solution of 2PACz is 3000 rpm, and the spinning time is 30 s; the annealing temperature is 80-90 °C, and the time is 3-5 min; In S3, the spinning speed of the electron transport material solution A or the electron transport material solution B is 3000-3500 rpm, and the spinning time is 30-40 s.

8. The preparation method according to claim 5, characterized in that, The concentration of the ethanol solution of 2PACz is 0.1-1.0 mg / mL; In the donor solution, the total concentration of the polymeric donor and the hindered phenolic antioxidant is 6-10 mg / mL; In the acceptor solution A, the concentration of BTP-eC9 is 6-12 mg / mL; In the acceptor solution B, the concentration of L8-BO is 8-12 mg / mL; In the electron transport material solution A, the concentration of PFN-Br is 0.1-1.0 mg / mL; In the electron transport material solution B, the concentration of PDINN is 0.1-1.0 mg / mL.

9. The preparation method according to claim 5, characterized in that, The volume of the 1,8-diiodooctane is 0.25-0.5% of the volume of the acceptor solution A; In the acceptor solution B, the concentration of 1,3-dibromo-5-chlorobenzene is 10-15 mg / mL.

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