Interface doped double-layer planar heterojunction organic solar cell and preparation method thereof
By using BCF or borate as interface dopant in organic solar cells, the electronic structure is modulated, exciton separation is promoted and charge recombination is reduced, thus solving the problems of low efficiency and complex processes in existing technologies and achieving high-efficiency photoelectric conversion.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- XI AN JIAOTONG UNIV
- Filing Date
- 2022-02-14
- Publication Date
- 2026-06-05
AI Technical Summary
Existing organic solar cells have low exciton transport and dissociation efficiency and high charge recombination rate, resulting in unsatisfactory photoelectric conversion efficiency. Furthermore, existing processes are cumbersome and unstable.
By using BCF or borate as interface dopant, the electronic structure is adjusted through interface doping, which promotes exciton separation and reduces charge recombination, thereby improving photoelectric conversion efficiency. A simple spin-coating process is used to prepare interface-doped bilayer planar heterojunction organic solar cells.
It significantly improves the photoelectric conversion efficiency of organic solar cells by up to 17%, and the process is simple and low-cost, without affecting the morphology of the active layer.
Smart Images
Figure CN114551725B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of organic solar cells, specifically relating to an interface-doped bilayer planar heterojunction organic solar cell and its preparation method. Background Technology
[0002] In response to global warming and the increasing depletion of fossil fuels, the development and utilization of renewable energy has received growing attention. Solar energy, with its significant advantages such as being unrestricted by geographical location, noiseless, pollution-free, and having low operating costs, is considered one of the most important methods for addressing the growing global energy demand and environmental pollution using renewable resources. Driven by technological advancements, economies of scale, increasingly fierce supply chain competition, and growing developer experience, the cost of renewable energy generation has fallen dramatically over the past decade. Between 2010 and 2019, the cost of solar photovoltaic power generation decreased by 82%.
[0003] Currently, commercially available traditional solar cells are mainly inorganic semiconductor solar cells such as monocrystalline silicon and polycrystalline silicon. Inorganic semiconductor solar cells have been widely used in photovoltaic power plants and aerospace. However, the widespread application of inorganic solar cells in daily life is limited by problems such as severe pollution in the industrial chain and huge energy consumption.
[0004] Organic solar cells are a new type of photovoltaic technology that has emerged in recent years, possessing unique advantages such as flexible wearable devices, building-integrated photovoltaics (BIPV), and indoor lighting applications. Currently, the highest single-cell efficiency for small-area applications has exceeded 18.2%, reaching the standard for commercial use. Therefore, organic solar cells have excellent development prospects. Their device structure consists of indium tin oxide (ITO) conductive glass, an electron transport layer, a hole transport layer, an active layer, and metal electrodes.
[0005] The working principle of organic solar cells is that excitons (electron-hole pairs) are generated in both the donor and acceptor regions of the active layer under illumination. When the excitons diffuse to the interface between the donor and acceptor materials, electrons are transferred from the donor LUMO to the acceptor LUMO due to the energy difference between the materials. Holes left in the donor HOMO combine with electrons in the acceptor LUMO to form excitons. After overcoming the Coulomb force (dissociation barrier), the excitons generate free electrons and holes. These holes and electrons then travel along the donor and acceptor regions to their respective electrodes and are collected. The processes of exciton generation, exciton dissociation, and charge collection determine the photoelectric conversion efficiency of organic solar cells. However, the main bottleneck of organic solar cells is the imperfect exciton transport and dissociation, charge transport, and charge recombination. The excessively high charge recombination rate in the active layer leads to insufficient hole-charge separation during cell operation, resulting in degraded device performance. Therefore, how to promote exciton separation, reduce the charge recombination rate, and thus improve the efficiency of organic solar cells is a problem that urgently needs to be solved.
[0006] Currently, for planar heterojunctions, reducing energy loss due to charge recombination can typically be achieved by adding an interfacial dipole layer to modulate the interfacial electric field. By adjusting the strength and direction of the interfacial dipole moment through the interfacial monolayer, the energy levels of the planar heterojunction can be adjusted, reducing charge recombination, enhancing charge separation, and increasing Voc. This can also be achieved by optimizing the local interfacial morphology. Furthermore, heat treatment and different solvents can be used to control molecular orientation and crystallinity, thereby reducing energy loss and achieving a high open-circuit voltage.
[0007] However, the two existing technologies are hampered by process and characterization limitations in practical applications. The process of modulating the interfacial electric field using the interfacial dipole layer is difficult to control, material selection is limited, heat treatment leads to cumbersome processes, and the standards for morphology optimization are vague, resulting in unstable device performance. Improving the efficiency of organic solar cells requires a method with a simple process and a well-defined mechanism. Summary of the Invention
[0008] The purpose of this invention is to address the problems in the prior art by providing an interface-doped bilayer planar heterojunction organic solar cell and its fabrication method, which significantly improves the photoelectric conversion efficiency of the bilayer planar heterojunction organic solar cell, has fewer controllable variables, is simple in process, and can also reduce costs.
[0009] To achieve the above objectives, the present invention provides the following technical solution:
[0010] In a first aspect, embodiments of the present invention provide an interface-doped bilayer planar heterojunction organic solar cell, comprising a conductive glass substrate, an electron transport layer, an active layer, a hole transport layer, and a metal electrode arranged sequentially from bottom to top, wherein the active layer is formed by interface doping of a bilayer planar heterojunction Y6 / J71 with BCF or borate.
[0011] The donor material J71 of the double-layer planar heterojunction Y6 / J71 has the following structural formula:
[0012]
[0013] The acceptor material Y6 of the bilayer planar heterojunction Y6 / J71 has the following structural formula:
[0014]
[0015] The BCF structure is as follows:
[0016]
[0017] The borate structure is as follows:
[0018]
[0019] As a preferred option:
[0020] The conductive glass substrate is made of transparent glass and a transparent indium tin oxide film deposited on the transparent glass;
[0021] The electron transport layer is made of zinc oxide;
[0022] The hole transport layer is made of an oxide of metallic molybdenum;
[0023] The metal electrode is made of aluminum.
[0024] Preferably, the BCF or borate doped at the interface in the active layer is a solution with a concentration of 0.01 mg / ml.
[0025] Secondly, embodiments of the present invention also provide an interface doping method for the interface-doped bilayer planar heterojunction organic solar cell, comprising:
[0026] Take BCF or borate powder, dissolve it in anhydrous ethanol, and stir at room temperature to obtain BCF or borate solution;
[0027] Dilute the BCF or borate solution to an intermediate concentration, then stir at room temperature to dilute to the target concentration.
[0028] Prepare a BCF or borate solution diluted to the target concentration by stirring.
[0029] As a preferred embodiment of the interface doping method described in this invention, 1 mg of the BCF or borate powder is weighed, dissolved in 1 ml of anhydrous ethanol, and stirred at 300 r / min for 24 h on a hot table at room temperature to obtain a 1 mg / ml BCF or borate solution.
[0030] The intermediate concentration is 0.1 mg / ml;
[0031] The mixture was then stirred at 300 rpm for 6 hours using a hot plate at room temperature, and the target concentration was 0.01 mg / ml.
[0032] The BCF or borate solution diluted to the target concentration is stirred at 300 rpm on a hot plate at room temperature for later use.
[0033] Thirdly, embodiments of the present invention also provide a method for fabricating the interface-doped bilayer planar heterojunction organic solar cell, comprising:
[0034] Take a conductive glass substrate and a blank glass substrate and clean them. Spin-coat an electron transport layer on the surface of the cleaned conductive glass substrate and spin-coat a water-soluble PEDOT:PSS on the surface of the cleaned blank glass substrate.
[0035] Weigh donor material J71 and acceptor material Y6, dissolve them separately in chloroform CF, and prepare single-component solutions for later use;
[0036] A solution of acceptor material Y6 is spin-coated onto the surface of a conductive glass substrate coated with an electron transport layer; a solution of donor material J71 is spin-coated onto the surface of a blank glass substrate coated with water-soluble PEDOT:PSS; and a solution of dopant, which is a BCF or borate solution diluted to a target concentration, is spin-coated onto the surface of the blank glass substrate coated with the solution of donor material J71.
[0037] A blank glass substrate coated with donor material J71 solution and dopant solution was placed on the surface of deionized water for water transfer printing, and a conductive glass substrate coated with acceptor material Y6 solution was used for surface bonding to prepare an active layer.
[0038] A hole transport layer is deposited on the surface of the prepared active layer by vapor deposition.
[0039] Metal electrodes are deposited on the surface of the hole transport layer;
[0040] After the above steps are completed, an interface-doped bilayer planar heterojunction organic solar cell is obtained.
[0041] In a preferred embodiment of the preparation method of the present invention, in the step of weighing donor material J71 and acceptor material Y6 and dissolving them separately in chloroform CF to prepare a single-component solution for later use, 2.25 mg of donor material J71 and 2.70 mg of acceptor material Y6 are weighed and dissolved separately in chloroform CF. The concentration of donor material J71 in the prepared single-component solution is 5 mg / ml, and the concentration of acceptor material Y6 is 6 mg / ml. The solution is stirred at 300 r / min at 50°C for 8 hours using a hot plate for later use.
[0042] As a preferred embodiment of the preparation method of the present invention, in the step of cleaning the conductive glass substrate and the blank glass substrate, the conductive glass substrate and the blank glass substrate are ultrasonically cleaned twice each with detergent, deionized water, acetone, anhydrous ethanol and isopropanol, respectively, for 30 minutes each time, and then dried with nitrogen.
[0043] Then, the conductive glass substrate and the blank glass substrate were subjected to plasma surface treatment for 20 minutes each.
[0044] As a preferred embodiment of the preparation method of the present invention, the steps of spin-coating an electron transport layer on the surface of a cleaned conductive glass substrate and spin-coating water-soluble PEDOT:PSS on the surface of a cleaned blank glass substrate include: spin-coating zinc oxide at 4500 r / min to prepare an electron transport layer on the surface of a cleaned conductive glass substrate and annealing at 200°C for 30 min; spin-coating water-soluble PEDOT:PSS at 1500 r / min on the surface of a cleaned blank glass substrate and annealing at 140°C for 3 min; and placing both the conductive glass substrate with completed surface spin-coating and the blank glass substrate in a glove box in a nitrogen atmosphere for later use.
[0045] Furthermore, as a preferred embodiment of the preparation method of the present invention, the steps of spin-coating acceptor material Y6 solution onto the surface of a conductive glass substrate coated with an electron transport layer, spin-coating donor material J71 solution onto the surface of a blank glass substrate coated with water-soluble PEDOT:PSS, and spin-coating dopant solution onto the surface of a blank glass substrate coated with donor material J71 solution specifically include: spin-coating acceptor material Y6 solution onto the surface of a conductive glass substrate coated with an electron transport layer at 3000 r / min for 30 s; spin-coating donor material J71 solution onto the surface of a blank glass substrate coated with water-soluble PEDOT:PSS at 1300 r / min for 30 s; and spin-coating a dopant solution with a concentration of 0.01 mg / ml onto the surface of a blank glass substrate coated with donor material J71 solution at 5000 r / min for 30 s.
[0046] The process involves placing a blank glass substrate coated with donor material J71 solution and dopant solution on a deionized water surface for water transfer printing, and then using a conductive glass substrate coated with acceptor material Y6 solution for surface bonding. After drying with nitrogen gas, the substrate is placed in a glove box and evacuated for 8 hours to completely remove the solvent and residual deionized water from the water transfer printing, thus obtaining the active layer.
[0047] Compared with the prior art, the present invention has at least the following beneficial effects:
[0048] This invention utilizes BCF or borate as dopants for interfacial doping of a bilayer planar heterojunction organic solar cell. Through interfacial doping between the dopant and the donor material J71, the electronic structure can be directly modulated, initiating charge transfer reactions and generating charge carriers, thus lowering the activation energy for carrier generation. Furthermore, it promotes exciton separation, reducing energy loss due to charge recombination. Interfacial doping also helps maintain optimal intermolecular stacking and built-in potential without affecting the morphology of the active layer. Both BCF and borate enhance the light absorption of the donor material J71 in the active layer, ultimately improving the photoelectric conversion efficiency of the organic solar cell. However, BCF provides a greater performance improvement. This invention only requires spin-coating a trace concentration of BCF interfacial doped layer to achieve a 17% increase in device photoelectric conversion efficiency, demonstrating a simple process and a significant efficiency improvement. Attached Figure Description
[0049] Figure 1 This is a schematic diagram of the reverse device structure of the interface-doped bilayer planar heterojunction organic solar cell of the present invention.
[0050] Figure 2 The graphs show the current density versus voltage relationship of the bilayer planar heterojunction organic solar cells of Examples 1, 2, and Comparative Example 1 of this invention.
[0051] Figure 3 AFM image of the J71 thin film, a donor material for the active layer of organic solar cells, in its undoped state;
[0052] Figure 4 AFM image of J71 thin film, donor material for active layer of organic solar cell, under BCF doping;
[0053] Figure 5 AFM image of J71 thin film, donor material for active layer of organic solar cell, under borate doping;
[0054] Figure 6 Two-dimensional GIWAXS diagram of J71 thin film, donor material for active layer of organic solar cell, in undoped state;
[0055] Figure 7 Two-dimensional GIWAXS plot of J71 thin film, donor material for active layer of organic solar cell, under BCF doping;
[0056] Figure 8 Two-dimensional GIWAXS plot of J71 thin film, donor material for the active layer of organic solar cells, under borate doping. Detailed Implementation
[0057] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.
[0058] This invention provides an interface-doped bilayer planar heterojunction organic solar cell, the device structure of which is as follows: Figure 1 As shown, the structure includes, from bottom to top, a conductive glass substrate 1, an electron transport layer 2, an active layer 3, a hole transport layer 4, and a metal electrode 5. The conductive glass substrate 1 is made of transparent glass and a transparent indium tin oxide film deposited on the transparent glass. The electron transport layer 2 is made of zinc oxide. The active layer 3 is formed by interfacial doping of a double-layer planar heterojunction Y6 / J71 with BCF or borate. The donor material J71 of the double-layer planar heterojunction Y6 / J71 has the following structural formula:
[0059]
[0060] The structure of the acceptor material Y6 in the bilayer planar heterojunction Y6 / J71 is as follows:
[0061]
[0062] The BCF structure is as follows:
[0063]
[0064] The structure of borates is as follows:
[0065]
[0066] The doping concentration of both the BCF solution and the borate solution was 0.01 mg / ml. The dopant solution was prepared as follows: 1 mg of dopant BCF or borate powder was weighed and dissolved in 1 ml of anhydrous ethanol. The solution was stirred at 300 rpm for 24 hours at room temperature to obtain a 1 mg / ml BCF or borate solution. This solution was then diluted to 0.1 mg / ml, stirred at 300 rpm for 6 hours at room temperature, and diluted again to 0.01 mg / ml. The solution was then stirred at 300 rpm for 6 hours at room temperature and set aside. The thickness of the resulting active layer 3 was approximately 60 nm. The hole transport layer 4 was made of MoOx and had a thickness of 10 nm. The metal electrode 5 was made of metallic Al and had a thickness of 100 nm.
[0067] The method for fabricating an interface-doped bilayer planar heterojunction organic solar cell according to the present invention includes the following steps:
[0068] S1: Weigh 2.25 mg of donor material J71 and 2.70 mg of acceptor material Y6, dissolve them separately in chloroform CF, and prepare a single-component solution. The concentration of donor material J71 in the single-component solution is 5 mg / ml, and the concentration of acceptor material Y6 is 6 mg / ml. Stir the solution at 300 r / min at 50℃ for 8 h using a hot plate for later use.
[0069] S2: Clean the conductive glass substrate 1 and the blank glass substrate. Clean the conductive glass substrate 1 twice each with detergent, deionized water, acetone, anhydrous ethanol and isopropanol, for 30 minutes each time. Then dry it with nitrogen. Clean the blank glass substrate in the same way to prepare it for deionized water transfer.
[0070] S3: Perform a 20-minute plasma surface treatment on the cleaned and dried conductive glass substrate 1. This treatment method utilizes the strong oxidizing properties of ozone generated under microwaves to clean residual organic matter on the ITO surface of the conductive glass substrate 1. At the same time, it can increase the oxygen vacancies on the ITO surface and improve the work function of the ITO surface. The blank glass substrate is treated in the same way.
[0071] S4: Electron transport layer 2 is prepared by spin-coating zinc oxide on the surface of the cleaned conductive glass substrate 1 at 4500 r / min and annealing at 200℃ for 30 min; water-soluble PEDOT:PSS is spin-coated on the surface of the cleaned blank glass substrate at 1500 r / min and annealed at 140℃ for 3 min; both the conductive glass substrate 1 and the blank glass substrate with completed surface spin-coating are placed in a glove box in a nitrogen atmosphere for later use.
[0072] S5: Apply acceptor material Y6 solution to the surface of conductive glass substrate 1 coated with electron transport layer 2 by dynamic spin coating at 3000 r / min for 30 s; apply donor material J71 solution to the surface of blank glass substrate coated with water-soluble PEDOT:PSS by dynamic spin coating at 1300 r / min for 30 s; apply dopant solution with a concentration of 0.01 mg / ml to the surface of blank glass substrate coated with donor material J71 solution by dynamic spin coating at 5000 r / min for 30 s. The dopant solution is BCF or borate solution diluted to the target concentration.
[0073] S6: Place the blank glass substrate coated with donor material J71 and dopant solution on the surface of deionized water for water transfer printing, and slowly attach the conductive glass substrate 1 coated with acceptor material Y6 to the surface of donor material J71. Then gently blow dry with nitrogen and place in the glove box for 8 hours to ensure complete removal of solvent and residual deionized water in water transfer printing, thus preparing active layer 3.
[0074] S7: MoOx was vapor-deposited on the surface of the prepared active layer 3 to obtain a hole transport layer 4 with a thickness of 10 nm.
[0075] S8: A metal electrode 5 with a thickness of 100 nm is prepared by evaporating Al on the surface of hole transport layer 4.
[0076] After the above steps are completed, an interface-doped bilayer planar heterojunction organic solar cell is obtained.
[0077] The thin film morphology characterization of the above-mentioned interface-doped bilayer planar heterojunction organic solar cells includes AFM and GIWAXS tests.
[0078] The sample preparation conditions for AFM testing are as follows: Clean the conductive glass substrate 1, and clean it twice each with deionized water and ethanol. Dry the cleaned ITO wafer with a nitrogen gun, treat it with UVO for 20 min to improve surface activity, and prepare the sample by spin coating. Spin coating the donor material J71 at 1300 r / min and the dopant at 5000 r / min.
[0079] The sample preparation conditions for GIWAXS testing are as follows: The silicon wafers are cut to appropriate sizes and cleaned twice each with deionized water and ethanol. The cleaned silicon wafers are dried with a nitrogen gun, treated with UVO for 20 minutes to improve surface activity, and the samples are prepared by spin coating. The donor material J71 is spin-coated at 1300 r / min, and the dopant is spin-coated at 5000 r / min.
[0080] The present invention will be further described in detail below with reference to specific embodiments and comparative examples. However, the implementation of the present invention is not limited thereto. For process parameters not specifically noted, conventional techniques can be referred to.
[0081] Example 1
[0082] The device structure of the interface-doped bilayer planar heterojunction organic solar cell in this embodiment is as follows:
[0083] ITO / ZnO / Y6 / BCF / J71 / MoOx / Al.
[0084] The fabrication process of the above-mentioned interface-doped bilayer planar heterojunction organic solar cell is as follows:
[0085] S1: Weigh 2.25 mg of donor material J71 and 2.70 mg of acceptor material Y6, dissolve them separately in chloroform CF, and prepare a single-component solution. The concentration of donor material J71 in the single-component solution is 5 mg / ml, and the concentration of acceptor material Y6 is 6 mg / ml. Stir the solution at 300 r / min at 50℃ for 8 h using a hot plate for later use.
[0086] S2: Clean the conductive glass substrate 1 and the blank glass substrate. Clean the conductive glass substrate 1 twice each with detergent, deionized water, acetone, anhydrous ethanol and isopropanol, for 30 minutes each time. Then dry it with nitrogen. Clean the blank glass substrate in the same way to prepare it for deionized water transfer.
[0087] S3: Perform a 20-minute plasma surface treatment on the cleaned and dried conductive glass substrate 1. This treatment method utilizes the strong oxidizing properties of ozone generated under microwaves to clean residual organic matter on the ITO surface of the conductive glass substrate 1. At the same time, it can increase the oxygen vacancies on the ITO surface and improve the work function of the ITO surface. The blank glass substrate is treated in the same way.
[0088] S4: Electron transport layer 2 is prepared by spin-coating zinc oxide on the surface of the cleaned conductive glass substrate 1 at 4500 r / min and annealing at 200℃ for 30 min; water-soluble PEDOT:PSS is spin-coated on the surface of the cleaned blank glass substrate at 1500 r / min and annealed at 140℃ for 3 min; both the conductive glass substrate 1 and the blank glass substrate with completed surface spin-coating are placed in a glove box in a nitrogen atmosphere for later use.
[0089] S5: Apply acceptor material Y6 solution to the surface of conductive glass substrate 1 coated with electron transport layer 2 by dynamic spin coating at 3000 r / min for 30 s; apply donor material J71 solution to the surface of blank glass substrate coated with water-soluble PEDOT:PSS by dynamic spin coating at 1300 r / min for 30 s; apply BCF solution to the surface of blank glass substrate coated with donor material J71 solution by dynamic spin coating at 5000 r / min for 30 s. This is the step of active layer interface doping. The preparation process of BCF solution is as follows: Weigh 1 mg of BCF powder in advance, dissolve it in 1 ml of anhydrous ethanol, stir at 300 r / min for 24 h on a hot stage at room temperature to obtain a 1 mg / ml BCF solution, dilute it to 0.1 mg / ml, stir at 300 r / min for 6 h on a hot stage, dilute it to 0.01 mg / ml, and stir at 300 r / min for use.
[0090] S6: Place the blank glass substrate coated with donor material J71 solution and BCF solution on the surface of deionized water for water transfer printing, and slowly attach the conductive glass substrate 1 coated with acceptor material Y6 solution to the surface of donor material J71. Then gently blow dry with nitrogen gas, place in the glove box and evacuate for 8 hours to ensure complete removal of solvent and residual deionized water in the water transfer printing, and prepare the active layer 3.
[0091] S7: MoOx was vapor-deposited on the surface of the prepared active layer 3 to obtain a hole transport layer 4 with a thickness of 10 nm.
[0092] S8: A metal electrode 5 with a thickness of 100 nm is prepared by evaporating Al on the surface of hole transport layer 4.
[0093] After the above steps are completed, an interface-doped bilayer planar heterojunction organic solar cell is obtained.
[0094] This embodiment describes the thin film morphology characterization of the aforementioned interface-doped bilayer planar heterojunction organic solar cell, including AFM and GIWAXS tests.
[0095] The sample preparation conditions for AFM testing are as follows: The conductive glass substrate 1 was cleaned twice each with deionized water and ethanol. The cleaned ITO wafer was dried with a nitrogen gun, treated with UVO for 20 min to improve surface activity, and then spin-coated. The substrate was then spin-coated with donor material J71 solution at 1300 r / min for 30 s, and with 0.01 mg / ml dopant BCF solution at 5000 r / min for 30 s.
[0096] The sample preparation conditions for GIWAXS testing are as follows: Silicon wafers are cut to appropriate sizes and cleaned twice each with deionized water and ethanol. After cleaning, the wafers are dried with a nitrogen gun, treated with UVO for 20 minutes to improve surface activity, and then spin-coated. The samples are prepared using a J71 donor solution at 1300 rpm for 30 seconds, and a 0.01 mg / ml BCF dopant solution at 5000 rpm for 30 seconds.
[0097] Example 2
[0098] The device structure of the interface-doped bilayer planar heterojunction organic solar cell in this embodiment is as follows:
[0099] ITO / ZnO / Y6 / Borate / J71 / MoOx / Al.
[0100] The fabrication process of the above-mentioned doped bilayer planar heterojunction organic solar cell is as follows:
[0101] S1: Weigh 2.25 mg of donor material J71 and 2.70 mg of acceptor material Y6, dissolve them separately in chloroform CF, and prepare a single-component solution. The concentration of donor material J71 in the single-component solution is 5 mg / ml, and the concentration of acceptor material Y6 is 6 mg / ml. Stir the solution at 300 r / min at 50℃ for 8 h using a hot plate for later use.
[0102] S2: Clean the conductive glass substrate 1 and the blank glass substrate. Clean the conductive glass substrate 1 twice each with detergent, deionized water, acetone, anhydrous ethanol and isopropanol, for 30 minutes each time. Then dry it with nitrogen. Clean the blank glass substrate in the same way to prepare it for deionized water transfer.
[0103] S3: Perform a 20-minute plasma surface treatment on the cleaned and dried conductive glass substrate 1. This treatment method utilizes the strong oxidizing properties of ozone generated under microwaves to clean residual organic matter on the ITO surface of the conductive glass substrate 1. At the same time, it can increase the oxygen vacancies on the ITO surface and improve the work function of the ITO surface. The blank glass substrate is treated in the same way.
[0104] S4: Electron transport layer 2 is prepared by spin-coating zinc oxide on the surface of the cleaned conductive glass substrate 1 at 4500 r / min and annealing at 200℃ for 30 min; water-soluble PEDOT:PSS is spin-coated on the surface of the cleaned blank glass substrate at 1500 r / min and annealed at 140℃ for 3 min; both the conductive glass substrate 1 and the blank glass substrate with completed surface spin-coating are placed in a glove box in a nitrogen atmosphere for later use.
[0105] S5: On the surface of a conductive glass substrate 1 coated with electron transport layer 2, the acceptor material Y6 solution is applied by dynamic spin-coating at 3000 r / min for 30 s; on the surface of a blank glass substrate coated with water-soluble PEDOT:PSS, the donor material J71 solution is applied by dynamic spin-coating at 1300 r / min for 30 s. On the surface of a blank glass substrate coated with donor material J71 solution, a borate solution is applied by dynamic spin-coating at 5000 r / min for 30 s. This is the step of active layer interface doping. The preparation process of the borate solution is as follows: 1 mg of borate powder is weighed in advance, dissolved in 1 ml of anhydrous ethanol, and stirred at 300 r / min for 24 h at room temperature to obtain a 1 mg / ml borate solution. This solution is then diluted to 0.1 mg / ml, stirred at 300 r / min for 6 h at room temperature, and diluted to 0.01 mg / ml. The solution is then stirred at 300 r / min at room temperature for later use.
[0106] S6: Place the blank glass substrate coated with donor material J71 solution and borate solution on the surface of deionized water for water transfer printing, and slowly attach the conductive glass substrate 1 coated with acceptor material Y6 solution to the surface of donor material J71. Then gently blow dry with nitrogen gas, place in the glove box and evacuate for 8 hours to ensure complete removal of solvent and residual deionized water in the water transfer printing, and prepare the active layer 3.
[0107] S7: MoOx was vapor-deposited on the surface of the prepared active layer 3 to obtain a hole transport layer 4 with a thickness of 10 nm.
[0108] S8: A metal electrode 5 with a thickness of 100 nm is prepared by evaporating Al on the surface of hole transport layer 4.
[0109] After the above steps are completed, an interface-doped bilayer planar heterojunction organic solar cell is obtained.
[0110] This embodiment describes the thin film morphology characterization of the aforementioned interface-doped bilayer planar heterojunction organic solar cell, including AFM and GIWAXS tests.
[0111] The sample preparation conditions for AFM testing are as follows: Clean the conductive glass substrate 1, rinsing it twice each with deionized water and ethanol. Dry the cleaned ITO wafer with a nitrogen gun, treat it with UVO for 20 min to improve surface activity, and prepare the sample by spin coating. Use donor material J71 solution for dynamic spin coating at 1300 r / min for 30 s, and use 0.01 mg / ml dopant borate solution for dynamic spin coating at 5000 r / min for 30 s.
[0112] The sample preparation conditions for GIWAXS testing are as follows: Silicon wafers are cut to appropriate sizes and cleaned twice each with deionized water and ethanol. After cleaning, the wafers are dried with a nitrogen gun, treated with UVO for 20 minutes to improve surface activity, and then spin-coated. The samples are prepared using a J71 donor solution at 1300 rpm for 30 seconds, and a 0.01 mg / ml borate dopant solution at 5000 rpm for 30 seconds.
[0113] Compare with Example 1
[0114] The structure of the double-layer planar heterojunction organic solar cell device without a doped layer in this comparative example is as follows:
[0115] ITO / ZnO / Y6 / J71 / MoOx / Al.
[0116] The fabrication process of the above-mentioned bilayer planar heterojunction organic solar cell is as follows:
[0117] S1: Weigh 2.25 mg of donor material J71 and 2.70 mg of acceptor material Y6, dissolve them separately in chloroform CF, and prepare a single-component solution. The concentration of donor material J71 in the single-component solution is 5 mg / ml, and the concentration of acceptor material Y6 is 6 mg / ml. Stir the solution at 300 r / min at 50℃ for 8 h using a hot plate for later use.
[0118] S2: Clean the conductive glass substrate 1 and the blank glass substrate. Clean the conductive glass substrate 1 twice each with detergent, deionized water, acetone, anhydrous ethanol and isopropanol, for 30 minutes each time. Then dry it with nitrogen. Clean the blank glass substrate in the same way to prepare it for deionized water transfer.
[0119] S3: Perform a 20-minute plasma surface treatment on the cleaned and dried conductive glass substrate 1. This treatment method utilizes the strong oxidizing properties of ozone generated under microwaves to clean residual organic matter on the ITO surface of the conductive glass substrate 1. At the same time, it can increase the oxygen vacancies on the ITO surface and improve the work function of the ITO surface. The blank glass substrate is treated in the same way.
[0120] S4: Electron transport layer 2 is prepared by spin-coating zinc oxide on the surface of the cleaned conductive glass substrate 1 at 4500 r / min and annealing at 200℃ for 30 min; water-soluble PEDOT:PSS is spin-coated on the surface of the cleaned blank glass substrate at 1500 r / min and annealed at 140℃ for 3 min; both the conductive glass substrate 1 and the blank glass substrate with completed surface spin-coating are placed in a glove box in a nitrogen atmosphere for later use.
[0121] S5: Apply acceptor material Y6 solution to the surface of conductive glass substrate 1 coated with electron transport layer 2 by dynamic spin coating at 3000 r / min for 30 s; apply donor material J71 solution to the surface of blank glass substrate coated with water-soluble PEDOT:PSS by dynamic spin coating at 1300 r / min for 30 s. Apply anhydrous ethanol to the surface of blank glass substrate coated with donor material J71 solution by dynamic spin coating at 5000 r / min for 30 s to eliminate the influence of dopant solvent on the device.
[0122] S6: Place the blank glass substrate coated with the donor material J71 solution on the surface of deionized water for water transfer printing, and slowly attach the conductive glass substrate 1 coated with the acceptor material Y6 solution to the surface of the donor material J71. Then gently blow it dry with nitrogen gas, place it in the glove box and evacuate for 8 hours to ensure complete removal of solvent and residual deionized water in the water transfer printing, and prepare the active layer 3.
[0123] S7: A hole transport layer MoOx with a thickness of 10 nm is deposited on the surface of the active layer after S6 treatment.
[0124] S8: A metal electrode Al with a thickness of 100 nm is deposited on the surface of the hole transport layer after the S7 treatment.
[0125] After the above steps are completed, the double-layer planar heterojunction organic solar cell device without doped layer in Comparative Example 1 is obtained.
[0126] This embodiment describes the thin film morphology characterization of the aforementioned undoped double-layer planar heterojunction organic solar cell device, including AFM and GIWAXS tests.
[0127] The sample preparation conditions for AFM testing are as follows: The conductive glass substrate 1 was cleaned twice each with deionized water and ethanol. The cleaned ITO wafer was dried with a nitrogen gun and treated with UVO for 20 minutes to improve surface activity. The sample was prepared by spin-coating, using a J71 donor solution at 1300 rpm for 30 seconds, followed by anhydrous ethanol at 5000 rpm for 30 seconds to eliminate the influence of the dopant solvent on surface roughness.
[0128] The sample preparation conditions for GIWAXS testing are as follows: Silicon wafers are cut to appropriate sizes and cleaned twice each with deionized water and ethanol. After cleaning, the wafers are dried with a nitrogen gun, treated with UVO for 20 minutes to improve surface activity, and then spin-coated. The sample is prepared using a J71 donor solution, spin-coated at 1300 rpm for 30 seconds, followed by spin-coating with anhydrous ethanol at 5000 rpm for 30 seconds to eliminate the influence of the dopant solvent on the morphology.
[0129] Figure 2 The table shows the current density versus voltage curves for the undoped bilayer planar heterojunction organic solar cell in Comparative Example 1 and the doped bilayer planar heterojunction organic solar cell in Example 1. Referring to Table 1, it can be seen that the undoped organic solar cell in Comparative Example 1 has an open-circuit voltage (Voc) of 0.86V and a short-circuit current density (Jsc) of 7.00mA / cm². 2 The BCF-doped organic solar cell in Example 1 has an open-circuit voltage (Voc) of 0.85V and a short-circuit current density (Jsc) of 8.20mA / cm². 2 The borate-doped organic solar cell in Example 2 has an open-circuit voltage (Voc) of 0.85V and a short-circuit current density (Jsc) of 7.63mA / cm². 2 This indicates that interface doping can effectively improve charge separation efficiency, increase light absorption of the active layer, and thus increase short-circuit current density. In comparison, BCF doping has a greater effect on increasing device current density.
[0130] AFM testing results show that the surface roughness of the BCF-doped or borate-doped J71 films does not change significantly compared to the undoped films. GIWAXS testing results show that the crystallinity and molecular orientation of the BCF-doped or borate-doped J71 films do not change significantly compared to the undoped films, i.e., the surface morphology does not change much. This indicates that interfacial doping with BCF or borate does not affect the morphology of J71 in the active layer.
[0131] Table 1
[0132]
[0133] Table 1 shows that the short-circuit current density (Jsc) of the BCF-doped bilayer planar heterojunction organic solar cell in Example 1 of this invention is 7.00 mA / cm². 2 Increased to 8.20 mA / cm 2 In Example 2 of this invention, the short-circuit current density (Jsc) of the borate-doped bilayer planar heterojunction organic solar cell was increased to 7.63 mA / cm². 2 Both dopants maintained good levels of open-circuit voltage (Voc) and fill factor (FF). In Example 1 of this invention, the photoelectric conversion efficiency (PCE) of the BCF-doped bilayer planar heterojunction organic solar cell increased from 4.06% to 4.75%, and in Example 2, the PCE of the borate-doped bilayer planar heterojunction organic solar cell increased from 4.06% to 4.42%. This demonstrates that interface doping of the bilayer planar heterojunction organic solar cell effectively improved its light absorption capacity, exciton separation efficiency, and carrier mobility without affecting the active layer morphology. In comparison, BCF doping resulted in a greater improvement in device performance, increasing the solar cell PCE from 4.06% to 4.75%, a 17% increase in device PCE.
[0134] The above description is merely a preferred embodiment of the present invention and is not intended to limit the technical solution of the present invention in any way. Those skilled in the art should understand that, without departing from the spirit and principles of the present invention, the technical solution can be modified and replaced in several simple ways, and these modifications and replacements are all within the scope of protection covered by the claims.
Claims
1. A method for interface doping of a bilayer planar heterojunction organic solar cell, characterized in that, The interface-doped bilayer planar heterojunction organic solar cell includes a conductive glass substrate (1), an electron transport layer (2), an active layer (3), a hole transport layer (4), and a metal electrode (5) arranged sequentially from bottom to top. The active layer (3) is formed by interface doping of bilayer planar heterojunction Y6 / J71 with BCF or borate. The donor material J71 of the double-layer planar heterojunction Y6 / J71 has the following structural formula: The acceptor material Y6 of the bilayer planar heterojunction Y6 / J71 has the following structural formula: The BCF structure is as follows: The borate structure is as follows: The conductive glass substrate (1) is made of transparent glass and a transparent indium tin oxide film deposited on the transparent glass; The electron transport layer (2) is made of zinc oxide; The hole transport layer (4) is made of an oxide of metallic molybdenum; The metal electrode (5) is made of aluminum. The BCF or borate doped at the interface in the active layer (3) is a solution with a concentration of 0.01 mg / ml. The interface-doped bilayer planar heterojunction organic solar cell uses BCF or borate as dopants for interface doping. The electronic structure is directly modulated through interface doping between the dopant and the donor material J71, resulting in charge transfer reactions and the generation of charge carriers, thus reducing the activation energy for carrier generation. Simultaneously, it promotes exciton separation, reducing energy loss due to charge recombination. Interface doping maintains the intermolecular stacking and built-in potential of the device without affecting the morphology of the active layer. Furthermore, BCF or borate enhances the light absorption of the donor material J71 in the active layer, improving the photoelectric conversion efficiency of the organic solar cell. Interface doping methods include: Take BCF or borate powder, dissolve it in anhydrous ethanol, and stir at room temperature to obtain BCF or borate solution; Dilute the BCF or borate solution to an intermediate concentration, then stir at room temperature to dilute to the target concentration. Prepare a BCF or borate solution diluted to the target concentration by stirring.
2. The interface doping method for interface-doped bilayer planar heterojunction organic solar cells according to claim 1, characterized in that: Weigh 1 mg of the BCF or borate powder, dissolve it in 1 ml of anhydrous ethanol, and stir at 300 r / min for 24 h on a hot table at room temperature to obtain a 1 mg / ml BCF or borate solution. The intermediate concentration is 0.1 mg / ml; The mixture was then stirred at 300 rpm for 6 hours using a hot plate at room temperature, and the target concentration was 0.01 mg / ml. The BCF or borate solution diluted to the target concentration is stirred at 300 rpm on a hot plate at room temperature for later use.
3. A method for fabricating an interface-doped bilayer planar heterojunction organic solar cell, characterized in that, The interface-doped bilayer planar heterojunction organic solar cell includes a conductive glass substrate (1), an electron transport layer (2), an active layer (3), a hole transport layer (4), and a metal electrode (5) arranged sequentially from bottom to top. The active layer (3) is formed by interface doping of bilayer planar heterojunction Y6 / J71 with BCF or borate. The donor material J71 of the double-layer planar heterojunction Y6 / J71 has the following structural formula: The acceptor material Y6 of the bilayer planar heterojunction Y6 / J71 has the following structural formula: The BCF structure is as follows: The borate structure is as follows: The conductive glass substrate (1) is made of transparent glass and a transparent indium tin oxide film deposited on the transparent glass; The electron transport layer (2) is made of zinc oxide; The hole transport layer (4) is made of an oxide of metallic molybdenum; The metal electrode (5) is made of aluminum. The BCF or borate doped at the interface in the active layer (3) is a solution with a concentration of 0.01 mg / ml. The interface-doped bilayer planar heterojunction organic solar cell uses BCF or borate as dopants for interface doping. The electronic structure is directly modulated through interface doping between the dopant and the donor material J71, resulting in charge transfer reactions and the generation of charge carriers, thus reducing the activation energy for carrier generation. Simultaneously, it promotes exciton separation, reducing energy loss due to charge recombination. Interface doping maintains the intermolecular stacking and built-in potential of the device without affecting the morphology of the active layer. Furthermore, BCF or borate enhances the light absorption of the donor material J71 in the active layer, improving the photoelectric conversion efficiency of the organic solar cell. Preparation methods include: Take a conductive glass substrate (1) and a blank glass substrate and clean them. Spin-coat an electron transport layer (2) on the surface of the cleaned conductive glass substrate (1) and spin-coat a water-soluble PEDOT:PSS on the surface of the cleaned blank glass substrate. Weigh donor material J71 and acceptor material Y6, dissolve them separately in chloroform CF, and prepare single-component solutions for later use; A solution of acceptor material Y6 is spin-coated on the surface of a conductive glass substrate (1) coated with an electron transport layer (2); a solution of donor material J71 is spin-coated on the surface of a blank glass substrate coated with water-soluble PEDOT:PSS; and a solution of dopant is spin-coated on the surface of a blank glass substrate coated with the solution of donor material J71, wherein the dopant solution is a BCF or borate solution diluted to the target concentration. A blank glass substrate coated with donor material J71 solution and dopant solution was placed on the surface of deionized water for water transfer printing, and a conductive glass substrate coated with acceptor material Y6 solution (1) was used for surface bonding to prepare an active layer (3). A hole transport layer (4) is deposited on the surface of the prepared active layer (3); Metal electrodes (5) are deposited on the surface of the hole transport layer (4); After the above steps are completed, an interface-doped bilayer planar heterojunction organic solar cell is obtained.
4. The method for fabricating an interface-doped bilayer planar heterojunction organic solar cell according to claim 3, characterized in that: In the step of weighing donor material J71 and acceptor material Y6 and dissolving them separately in chloroform CF to prepare a single-component solution for later use, 2.25 mg of donor material J71 and 2.70 mg of acceptor material Y6 were weighed and dissolved separately in chloroform CF. The concentration of donor material J71 in the prepared single-component solution was 5 mg / ml, and the concentration of acceptor material Y6 in the solution was 6 mg / ml. The solution was stirred at 300 r / min at 50°C for 8 hours using a hot plate for later use.
5. The method for fabricating an interface-doped bilayer planar heterojunction organic solar cell according to claim 3, characterized in that: In the step of cleaning the conductive glass substrate (1) and the blank glass substrate, the conductive glass substrate (1) and the blank glass substrate are ultrasonically cleaned twice each with detergent, deionized water, acetone, anhydrous ethanol and isopropanol, respectively, for 30 minutes each time, and then dried with nitrogen. Then, the conductive glass substrate (1) and the blank glass substrate were subjected to plasma surface treatment for 20 minutes.
6. The method for fabricating an interface-doped bilayer planar heterojunction organic solar cell according to claim 3, characterized in that: The steps of spin-coating an electron transport layer (2) on the surface of a cleaned conductive glass substrate (1) and spin-coating water-soluble PEDOT:PSS on the surface of a cleaned blank glass substrate include: spin-coating zinc oxide on the surface of the cleaned conductive glass substrate (1) at 4500 r / min to prepare an electron transport layer (2), and annealing at 200°C for 30 min; spin-coating water-soluble PEDOT:PSS on the surface of the cleaned blank glass substrate at 1500 r / min, and annealing at 140°C for 3 min; and placing both the conductive glass substrate (1) with completed surface spin-coating and the blank glass substrate in a glove box in a nitrogen atmosphere for later use.
7. The method for fabricating an interface-doped bilayer planar heterojunction organic solar cell according to claim 6, characterized in that: The steps of spin-coating acceptor material Y6 solution on the surface of conductive glass substrate (1) coated with electron transport layer (2), spin-coating donor material J71 solution on the surface of blank glass substrate coated with water-soluble PEDOT:PSS, and spin-coating dopant solution on the surface of blank glass substrate coated with donor material J71 solution specifically include: spin-coating acceptor material Y6 solution on the surface of conductive glass substrate (1) coated with electron transport layer (2) at 3000 r / min for 30 s; spin-coating donor material J71 solution on the surface of blank glass substrate coated with water-soluble PEDOT:PSS at 1300 r / min for 30 s; and spin-coating dopant solution with a concentration of 0.01 mg / ml on the surface of blank glass substrate coated with donor material J71 solution at 5000 r / min for 30 s. The blank glass substrate coated with donor material J71 solution and dopant solution is placed on the surface of deionized water for water transfer printing, and then a conductive glass substrate coated with acceptor material Y6 solution (1) is used for surface bonding. After drying with nitrogen gas, it is placed in a glove box and vacuumed for 8 hours to completely remove the solvent and residual deionized water in the water transfer printing, and an active layer (3) is obtained.