Layer-by-layer deposition type organic photovoltaic device assisted by delayed fluorescent material and preparation method
By doping the delayed fluorescence material BN-STO into organic photovoltaic devices, the problem of low dissociation efficiency of photogenerated excitons was solved, the open circuit voltage and photoelectric conversion efficiency were improved, and low-cost and short-cycle performance improvement was achieved.
Patent Information
- Application Number
- CN202510751501.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-06
- Publication Date
- 2025-09-09
AI Technical Summary
Photogenerated excitons in organic photovoltaic devices are difficult to dissociate effectively, resulting in high voltage loss and limiting the efficiency of photocurrent generation.
The delayed fluorescence material BN-STO is used as a reverse intersystem crossing activator, doped in the wide bandgap polymer donor PM1, and combined with the non-fullerene small molecule acceptor L8-BO to improve exciton dissociation and diffusion through fluorescence resonance energy transfer and thermally activated delayed fluorescence effect.
It reduces voltage loss, improves open-circuit voltage and photoelectric conversion efficiency, and achieves performance improvement of organic photovoltaic devices with lower cost and shorter R&D cycle.
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Figure CN120614939A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of organic solar cells, and in particular to a delayed fluorescent material-assisted layer-by-layer deposition type organic photovoltaic device and a preparation method thereof. Background Art
[0002] Global climate change and the energy crisis have driven an urgent demand for clean energy technologies, with solar energy being a renewable, widely distributed, and abundant energy source. The unsustainability and high carbon emissions of traditional fossil fuels have accelerated the transformation of the energy structure. Currently, crystalline silicon photovoltaics dominate the market, but limitations such as high manufacturing costs, material rigidity, and high energy consumption are becoming increasingly apparent. At the same time, third-generation photovoltaic technologies, represented by perovskites and organic photovoltaics (OPVs), are rapidly emerging. Based on polymer or small molecule materials, organic photovoltaics offer the core advantages of flexible materials and processes, lightweight and flexible design, low-light response, and translucency. They are expected to achieve commercialization breakthroughs in the next 5 to 10 years and become an indispensable component of the green energy system.
[0003] In the early stages of organic photovoltaic development, the bulk heterojunction (BHJ) structure formed an interpenetrating network through donor / acceptor blending. Although it effectively promoted exciton separation and charge transport, its disordered phase separation characteristics made it difficult to precisely control the morphology of the active layer, and its efficiency and stability were easily affected by fluctuations in processing conditions. In recent years, layer-by-layer deposition (LbL) organic photovoltaics have rapidly emerged. By independently depositing layers of donor and acceptor materials, precise control of vertical phase distribution and interface energy levels has been achieved. Compared with traditional BHJ, LbL technology has three core advantages: first, it suppresses disordered phase separation through step-by-step processing to form a more stable interpenetrating structure; second, it optimizes exciton dissociation and charge transfer pathways to reduce recombination losses; and third, it is compatible with flexible substrates and roll-to-roll processes, and can prepare large-area uniform devices, providing an innovative path for the industrialization of high-performance, low-cost organic photovoltaics.
[0004] In organic photovoltaic devices, the spatial distribution of photogenerated excitons has an important influence on efficiency. Studies on the Lambert-Beer law show that when incident light passes through an indium tin oxide (ITO) glass substrate, photogenerated excitons are concentrated near the ITO anode interface. Because the thickness of the organic semiconductor layer far exceeds the exciton diffusion length, it is difficult for the excitons generated at the interface to migrate to the donor-acceptor interpenetrating network interface to complete effective dissociation. This seriously restricts the efficiency of photocurrent generation and becomes a core challenge for improving the performance of LbL devices. At the same time, the large exciton binding energy of the Frenkel excitons in organic semiconductor materials leads to large voltage losses, which is also the main reason for the low voltage of organic photovoltaics. How to reduce voltage losses and increase voltage are scientific problems that need to be solved urgently in photovoltaic devices. Summary of the Invention
[0005] The present application provides a delayed fluorescent material-assisted layer-by-layer deposition type organic photovoltaic device and a preparation method, which solves the problem of organic photovoltaic voltage loss and the problem of exciton diffusion near the electrode, and provides a solution for improving the energy conversion efficiency of organic photovoltaics.
[0006] To solve the above technical problems, in the first aspect, the embodiments of the present application provide a delayed fluorescence material-assisted layer-by-layer deposition type organic photovoltaic device, comprising: a substrate and a conductive anode, an anode modification layer, an electron donor layer, an electron acceptor layer, a cathode modification layer and a metal cathode stacked in sequence on the substrate; the material of the electron donor layer is a wide bandgap polymer donor PM1 doped with a delayed fluorescence additive BN-STO; the material of the electron acceptor layer is a non-fullerene small molecule acceptor L8-BO doped with a solid additive trichlorobenzene.
[0007] In some exemplary embodiments, the doping amount of the delayed fluorescence additive BN-STO is 0.5 wt % of the wide bandgap polymer donor PM1.
[0008] In some exemplary embodiments, the doping amount of the solid additive trichlorobenzene is 125 wt % of the non-fullerene small molecule acceptor L8-BO.
[0009] In some exemplary embodiments, the chemical formula of the polymer donor PM1 is:
[0010]
[0011] The chemical structure of the delayed fluorescence additive BN-STO is:
[0012]
[0013] The chemical structure of the non-fullerene small molecule receptor L8-BO is:
[0014]
[0015] In some exemplary embodiments, the substrate is a transparent glass substrate; the material of the conductive anode is indium tin oxide; the material of the anode modification layer is PEDOT:PSS; the material of the cathode modification layer is PNDIT-F3N; and the material of the metal cathode is Ag.
[0016] In a second aspect, an embodiment of the present application also provides a method for preparing a delayed fluorescence material-assisted layer-by-layer deposition type organic photovoltaic device, comprising the following steps: providing a substrate and forming a conductive anode on the substrate; spin-coating an anode modification material on the conductive anode to form an anode modification layer; spin-coating a donor film on the anode modification layer to form an electron donor layer; the donor film is a wide bandgap polymer donor PM1 material doped with a delayed fluorescence additive BN-STO; spin-coating an acceptor film on the electron donor layer to form an electron acceptor layer; the acceptor film is a non-fullerene small molecule acceptor L8-BO material doped with a solid additive trichlorobenzene; spin-coating a cathode modification material on the electron acceptor layer to form a cathode modification layer; and forming a metal cathode on the cathode modification layer.
[0017] In some exemplary embodiments, a wide bandgap polymer donor PM1 material doped with a delayed fluorescence additive BN-STO comprises the following steps: dissolving PM1 in chloroform and stirring to dissolve to obtain a PM1 solution; the concentration of the PM1 solution is 7 mg / ml to 9 mg / ml; dissolving BN-STO in chloroform and stirring to dissolve to obtain a BN-STO solution; the concentration of the BN-STO solution is 0.003 mg / ml to 0.005 mg / ml; mixing the BN-STO solution with the PM1 solution to obtain a mixed solution of PM1:BN-STO; the volume ratio of the BN-STO solution to the PM1 solution is 1:0.01; and the mass ratio of BN-STO to PM1 is 1:0.005.
[0018] In some exemplary embodiments, the concentration of the PM1 solution is 8 mg / ml; the concentration of the BN-STO solution is 0.004 mg / ml.
[0019] In some exemplary embodiments, a non-fullerene small molecule receptor L8-BO material doped with a solid additive trichlorobenzene comprises the following steps: dissolving L8-BO and trichlorobenzene in chloroform at a ratio of 1:1.25, and stirring to dissolve to obtain an L8-BO receptor layer solution; the concentration of L8-BO in the L8-BO receptor layer solution is 7 mg / ml to 9 mg / ml, and the concentration of trichlorobenzene is 8.75 mg / ml to 11.25 mg / ml.
[0020] In some exemplary embodiments, the substrate is a transparent glass substrate; the material of the conductive anode is indium tin oxide; the anode modification material is PEDOT:PSS; the cathode modification material is PNDIT-F3N; and the material of the metal cathode is Ag.
[0021] The technical solution provided by the embodiments of the present application has at least the following advantages:
[0022] An embodiment of the present application provides a delayed fluorescence material-assisted layer-by-layer deposition-type organic photovoltaic device and a preparation method. The device includes: a substrate and a conductive anode, an anode modification layer, an electron donor layer, an electron acceptor layer, a cathode modification layer and a metal cathode stacked in sequence on the substrate; the material of the electron donor layer is a wide bandgap polymer donor PM1 doped with a delayed fluorescence additive BN-STO; the material of the electron acceptor layer is a non-fullerene small molecule acceptor L8-BO doped with a solid additive trichlorobenzene.
[0023] This application places the TADF material BN-STO as a reverse intersystem crossing activator in the donor layer, mainly due to the following reasons: (1) BN-STO has a strong thermally activated delayed fluorescence effect, which can induce reverse intersystem crossing in the donor and acceptor materials, reduce non-radiative triplet excitons, and thus reduce energy loss; (2) The addition of BN-STO can increase the exciton diffusion distance of the donor and acceptor materials through fluorescence resonance energy transfer, and improve the exciton dissociation near the electrode. Based on this, the voltage loss of the LbL type organic photovoltaic is reduced and the exciton dissociation is improved. Based on the above advantages, by introducing the delayed fluorescence additive, the photoelectric conversion efficiency of the organic photovoltaic device with PM1 / L8-BO as the active layer is increased from 18.54% to 19.65%, and the open circuit voltage is increased from 0.895V to 0.911V, which is the highest open circuit voltage value based on this binary material system. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] One or more embodiments are exemplarily described by the pictures in the corresponding drawings. These exemplifications do not constitute limitations on the embodiments. Unless otherwise stated, the pictures in the drawings do not constitute proportional limitations.
[0025] Figure 1 This is a schematic structural diagram of a delayed fluorescence material-assisted layer-by-layer deposition type organic photovoltaic device provided in an embodiment of the present application.
[0026] Figure 2 The current-voltage curves and external quantum efficiency curves of two organic photovoltaic devices provided in the examples of this application are shown. DETAILED DESCRIPTION
[0027] As can be seen from the background technology, compared with traditional BHJ, LbL technology has three core advantages. However, the exciton binding energy of organic semiconductor materials is large and the voltage loss is high. In order to solve this problem, most researchers use material design methods such as asymmetric acceptor design and synthesis (Adv.Energy Mater.2023,2204154), strong luminescent donor design and synthesis (Adv.Mater.2021,33,2102420) or ternary strategies (Adv.EnergyMater.2024,2402268) and other device engineering methods. This material design method requires continuous trial and error, and the cost recovery cycle is long. The ternary strategy to reduce voltage loss is essentially also dependent on new materials with low voltage loss.
[0028] At the same time, for LbL organic photovoltaics, due to the limited exciton diffusion distance of organic semiconductor materials, the exciton dissociation efficiency near the electrode is difficult to guarantee. To address this problem, researchers mostly use strategies such as solvent additives (ACSEnergy Lett. 2020, 5, 3637-3646) and dissociation enhancement layers (Adv. Funct. Mater. 2023, 33, 2215204) to increase the donor-acceptor interface and enhance exciton dissociation. However, the effect of this optimization process is limited, and to a certain extent, it reduces the advantages of the LbL strategy in increasing vertical structural phase separation.
[0029] In organic photovoltaic devices, the thickness of the organic semiconductor layer far exceeds the exciton diffusion length, making it difficult for excitons generated at the interface to migrate to the donor-acceptor interpenetrating network interface for effective dissociation. This severely limits the efficiency of photocurrent generation and becomes a core challenge in improving LbL device performance. Therefore, reducing voltage loss and increasing voltage are urgent scientific issues that need to be addressed in photovoltaic devices.
[0030] To solve the above-mentioned technical problems, the embodiments of the present application provide a delayed fluorescence material-assisted layer-by-layer deposition type organic photovoltaic device and preparation method, the device comprising: a substrate and a conductive anode, an anode modification layer, an electron donor layer, an electron acceptor layer, a cathode modification layer and a metal cathode stacked in sequence on the substrate; the material of the electron donor layer is a wide bandgap polymer donor PM1 doped with a delayed fluorescence additive BN-STO; the material of the electron acceptor layer is a non-fullerene small molecule acceptor L8-BO doped with a solid additive trichlorobenzene. The present application proposes a strategy of doping a thermally activated delayed fluorescence (TADF) material as a reverse intersystem crossing activator in LbL type organic photovoltaics, inducing and enhancing reverse intersystem crossing of the donor and acceptor materials, inducing the conversion of triplet excitons into singlet excitons, reducing energy loss, and improving the exciton lifetime.
[0031] The embodiments of the present application will be described in detail below with reference to the accompanying drawings so that those skilled in the art can better understand the present application and implement it.
[0032] The following contents are all for the purpose of explaining in detail the specific examples of the specific implementation process provided by the technical solutions to be protected in this application. However, this application may also adopt other implementation methods different from this description. Technical personnel in this field can, under the guidance of the ideas of this application, adopt different technical solutions to achieve the contents within the scope of this application. Therefore, this application is not strictly limited to the specific implementation cases below.
[0033] An embodiment of the present application provides a layer-by-layer deposition-type organic photovoltaic device assisted by a delayed fluorescence material, comprising: a substrate and a conductive anode, an anode modification layer, an electron donor layer, an electron acceptor layer, a cathode modification layer, and a metal cathode stacked in sequence on the substrate; the material of the electron donor layer is a wide-bandgap polymer donor PM1 doped with a delayed fluorescence additive BN-STO; the material of the electron acceptor layer is a non-fullerene small molecule acceptor L8-BO doped with a solid additive trichlorobenzene.
[0034] In some embodiments, the substrate is a transparent glass substrate; the material of the conductive anode is indium tin oxide (ITO); the material of the anode modification layer is PEDOT:PSS; the material of the cathode modification layer is PNDIT-F3N; and the material of the metal cathode is Ag.
[0035] like Figure 1 As shown, on the substrate and the conductive anode (ITO / glass), an anode modification layer (PEDOT:PSS), an electron donor layer (PM1:BN-STO), an electron acceptor layer (L8-BO), a cathode modification layer (PNDIT-F3N) and a metal cathode (Ag) are formed in sequence.
[0036] In some embodiments, the doping amount of the delayed fluorescence additive BN-STO is 0.5wt% of the wide bandgap polymer donor PM1. In this application, 0.5wt% of BN-STO additive is added to PM1, while no BN-STO additive is added to the comparative device. The current-voltage curves and external quantum efficiency curves of the two organic photovoltaic devices obtained are as follows: Figure 2 As shown, (a) is the current-voltage curve of two organic photovoltaic devices, and (b) is the external quantum efficiency curve.
[0037] At a light intensity of 100 mW / cm 2 Under AM1.5 simulated sunlight, the current-voltage curves of the device with and without BN-STO were tested. The open circuit voltage of the device without BN-STO was 0.895V and the short circuit current density was 26.68mA / cm 2, the fill factor is 77.62%, and the photoelectric conversion efficiency is 18.54%. The device with BN-STO added has an open circuit voltage of 0.911V and a short circuit current density of 27.26mA / cm 2 , the filling factor is 79.10% and the photoelectric conversion efficiency is 19.65%.
[0038] In some embodiments, the doping amount of the solid additive trichlorobenzene is 125 wt % of the non-fullerene small molecule acceptor L8-BO.
[0039] In some embodiments, the chemical formula of the polymer donor PM1 is:
[0040]
[0041] The chemical structure of the non-fullerene small molecule receptor L8-BO is:
[0042]
[0043] The chemical structure of the delayed fluorescence additive BN-STO is:
[0044]
[0045] It should be noted that in this application, the delayed fluorescence additive is the TADF material BN-STO. Currently, there are many types of delayed fluorescence materials, and other TADF materials and even delayed fluorescent materials may also play the same role. In some systems, phosphorescent materials and long-life fluorescent materials may also play a role in increasing the exciton diffusion distance.
[0046] The electron donor layer of this application is spin-coated from an 8mg / ml PM1 solution with 0.5wt% of a BN-STO additive. The electron acceptor layer is spin-coated from an 8mg / ml L8-BO solution with 10mg / ml of the volatile solid additive trichlorobenzene (TCB) added to control the morphology. The substrate is transparent glass, the conductive anode is a transparent conductive anode (ITO), the anode modification layer is PEDOT:PSS with an Al4083 formula, the cathode modification layer is PNDIT-F3N, and the metal cathode material is Ag.
[0047] In addition, an embodiment of the present application further provides a method for preparing a delayed fluorescent material-assisted layer-by-layer deposition type organic photovoltaic device, comprising the following steps:
[0048] Step 1: providing a substrate and forming a conductive anode on the substrate.
[0049] Step 2: Spin-coating an anode modification material on the conductive anode to form an anode modification layer.
[0050] Step 3: spin-coat a donor film on the anode modification layer to form an electron donor layer; the donor film is a wide bandgap polymer donor PM1 material doped with a delayed fluorescence additive BN-STO.
[0051] Step 4: spin-coating an acceptor film on the electron donor layer to form an electron acceptor layer; the acceptor film is a non-fullerene small molecule acceptor L8-BO material doped with a solid additive trichlorobenzene.
[0052] Step 5: Spin-coat the cathode modification material on the electron acceptor layer to form a cathode modification layer.
[0053] Step 6: forming a metal cathode on the cathode modification layer.
[0054] It should be noted that after the donor film and the acceptor film were spin-coated, they were annealed at 100° C. for 5 min to remove the volatile solid additive trichlorobenzene (TCB) and to control the morphology.
[0055] In some embodiments, a wide bandgap polymer donor PM1 material doped with a delayed fluorescence additive BN-STO has a preparation process comprising the following steps: dissolving PM1 in chloroform and stirring to dissolve to obtain a PM1 solution; the concentration of the PM1 solution is 7 mg / ml to 9 mg / ml; dissolving BN-STO in chloroform and stirring to dissolve to obtain a BN-STO solution; the concentration of the BN-STO solution is 0.003 mg / ml to 0.005 mg / ml; mixing the BN-STO solution with the PM1 solution to obtain a mixed solution of PM1:BN-STO; the volume ratio of the BN-STO solution to the PM1 solution is 1:0.01; and the mass ratio of BN-STO to PM1 is 1:0.005.
[0056] In some embodiments, the concentration of the PM1 solution is 8 mg / ml; the concentration of the BN-STO solution is 0.004 mg / ml.
[0057] In some embodiments, a non-fullerene small molecule receptor L8-BO material doped with a solid additive trichlorobenzene has a preparation process comprising the following steps: dissolving L8-BO and trichlorobenzene in chloroform at a ratio of 1:1.25, and stirring to dissolve to obtain an L8-BO receptor layer solution; the L8-BO concentration in the L8-BO receptor layer solution is 7 mg / ml to 9 mg / ml, and the trichlorobenzene concentration is 8.75 mg / ml to 11.25 mg / ml.
[0058] In some embodiments, the substrate is a transparent glass substrate; the material of the conductive anode is indium tin oxide; the anode modification material is PEDOT:PSS; the cathode modification material is PNDIT-F3N; and the material of the metal cathode is Ag.
[0059] The following is a detailed introduction to the preparation method of the delayed fluorescent material-assisted layer-by-layer deposition type organic photovoltaic device provided in the present application through specific examples.
[0060] Dissolve 4.00 mg of PM1 in 500 μl of chloroform and incubate at 40°C on a magnetic stirrer for 2-3 hours to obtain an 8 mg / ml PM1 solution. Dissolve 0.80 mg of BN-STO in 200 μl of chloroform and incubate at 40°C on a magnetic stirrer for 2-3 hours to obtain a 0.004 mg / ml BN-STO solution. Mix 5 μl of the BN-STO solution with 500 μl of the PM1 solution to obtain a PM1:BN-STO (1:0.005) mixed solution. Dissolve 4.00 mg of L8-BO and 5.00 mg of TCB in 500 μl of chloroform and incubate at 40°C on a magnetic stirrer for 2-3 hours to obtain an 8 mg / ml L8-BO receptor layer solution. 0.50 mg of PNDIT-F3N was dissolved in 1000 μl of a mixture of methanol and acetic acid (1:0.005) and stirred for 2-3 hours to obtain a 0.5 mg / ml PNDIT-F3N solution. The etched ITO conductive glass was then subjected to a series of washes, followed by deionized water, and anhydrous ethanol, followed by ultrasonic treatment for 2.5 hours, 1.5 hours, and 0.5 hours, respectively. After cleaning, the substrate was blown dry with dry nitrogen. The dried substrate was treated in a plasma surface treatment chamber for 80 seconds. The PEDOT:PSS solution was spin-coated onto an ITO / glass substrate at 5000 rpm for 30 seconds. The PEDOT:PSS-coated substrate was then annealed on a hot plate at 150°C for 15 minutes. After annealing, the substrate was immediately transferred to a glove box filled with high-purity nitrogen. The substrate on which PEDOT:PSS was spin-coated was spin-coated with PM1 solution or PM1:BN-STO at a speed of 2600 rpm for 30 seconds to obtain a donor layer. The substrate on which the donor layer was spin-coated was spin-coated with L8-BO acceptor layer solution at a speed of 2600 rpm for 30 seconds to obtain an acceptor layer. The substrate on which the active layer was spin-coated was then placed on a heating table at 100°C for annealing for 5 minutes. A concentrated PNDIT-F3N solution was then spin-coated on the active layer at a speed of 2000 rpm for 30 seconds. Finally, a 100 nm thick Ag electrode (cathode) was evaporated using an evaporator to obtain an effective area of 3.8 mm 2 organic photovoltaic devices.
[0061] Compared with the prior art, the delayed fluorescent material-assisted layer-by-layer deposition organic photovoltaic device and preparation method provided in this application have the following advantages:
[0062] (1) Low cost and short R&D cycle. Currently, the existing organic photovoltaics have high voltage loss, and the main solutions to this problem focus on the design and synthesis of new materials and ternary strategies. These methods essentially use materials with lower energy loss, which are often more difficult to synthesize and have higher costs. In addition, the synthesis of new materials relies on a lot of trial and error, with a low input-output ratio and a long cost recovery cycle. This application uses a delayed fluorescence doping strategy to achieve organic photovoltaics with lower energy loss. Only a very small amount of delayed fluorescence doping is required to reduce the voltage loss by more than 0.01V. Compared with traditional optimization strategies, it has the advantages of low material cost and short R&D cycle.
[0063] (2) Enhancement of the exciton lifetime and diffusion distance of the donor-acceptor materials. The existing LbL technology prepares the active layer by gradually depositing the donor layer and the acceptor layer. The vertical phase separation of the donor and the acceptor is large, and the excitons near the electrode are difficult to be effectively utilized. The mainstream solution tends to increase the donor-acceptor interface. These strategies actually solve the most fundamental contradiction of this problem, namely the need for a rich donor-acceptor interface for good exciton dissociation and the need for vertical structural phase separation of the donor and the acceptor for good carrier collection. This is caused by the lower exciton lifetime and diffusion distance of organic semiconductor materials. This application successfully achieved the enhancement of the exciton lifetime and diffusion distance of the donor-acceptor material by delaying the doping of fluorescent materials to induce reverse intersystem crossing of the donor and the acceptor and forming energy transfer. While optimizing the exciton dissociation, it maintains a good vertical structural phase separation, balances the exciton dissociation and carrier collection, and improves the photoelectric conversion efficiency.
[0064] Based on the above technical solution, the embodiment of the present application provides a delayed fluorescence material-assisted layer-by-layer deposition type organic photovoltaic device and a preparation method. The device includes: a substrate and a conductive anode, an anode modification layer, an electron donor layer, an electron acceptor layer, a cathode modification layer and a metal cathode stacked in sequence on the substrate; the material of the electron donor layer is a wide bandgap polymer donor PM1 doped with a delayed fluorescence additive BN-STO; the material of the electron acceptor layer is a non-fullerene small molecule acceptor L8-BO doped with a solid additive trichlorobenzene.
[0065] This application places the TADF material BN-STO as a reverse intersystem crossing activator in the donor layer, mainly due to the following reasons: (1) BN-STO has a strong thermally activated delayed fluorescence effect, which can induce reverse intersystem crossing in the donor and acceptor materials, reduce non-radiative triplet excitons, and thus reduce energy loss; (2) The addition of BN-STO can increase the exciton diffusion distance of the donor and acceptor materials through fluorescence resonance energy transfer, and improve the exciton dissociation near the electrode. Based on this, the voltage loss of the LbL type organic photovoltaic is reduced and the exciton dissociation is improved. Based on the above advantages, by introducing the delayed fluorescence additive, the photoelectric conversion efficiency of the organic photovoltaic device with PM1 / L8-BO as the active layer is increased from 18.54% to 19.65%, and the open circuit voltage is increased from 0.895V to 0.911V, which is the highest open circuit voltage value based on this binary material system.
[0066] Those skilled in the art will appreciate that the above-described embodiments are specific examples for implementing the present application, and that in actual applications, various changes in form and detail may be made thereto without departing from the spirit and scope of the present application. Any person skilled in the art may make changes and modifications without departing from the spirit and scope of the present application. Therefore, the scope of protection of the present application shall be subject to the scope defined in the claims.
Claims
1. A delayed fluorescent material-assisted layer-by-layer deposition type organic photovoltaic device, characterized in that: include: A substrate and a conductive anode, an anode modification layer, an electron donor layer, an electron acceptor layer, a cathode modification layer and a metal cathode sequentially stacked on the substrate; The material of the electron donor layer is a wide bandgap polymer donor PM1 doped with a delayed fluorescence additive BN-STO; The material of the electron acceptor layer is a non-fullerene small molecule acceptor L8-BO doped with a solid additive trichlorobenzene.
2. The delayed fluorescent material-assisted layer-by-layer deposition organic photovoltaic device according to claim 1, characterized in that: The doping amount of the delayed fluorescence additive BN-STO is 0.5wt% of the wide bandgap polymer donor PM1.
3. The delayed fluorescent material-assisted layer-by-layer deposition organic photovoltaic device according to claim 1, characterized in that: The doping amount of the solid additive trichlorobenzene is 125 wt % of the non-fullerene small molecule acceptor L8-BO.
4. The delayed fluorescent material-assisted layer-by-layer deposition organic photovoltaic device according to claim 1, characterized in that: The chemical structural formula of the polymer donor PM1 is: The chemical structural formula of the delayed fluorescence additive BN-STO is: The chemical structural formula of the non-fullerene small molecule receptor L8-BO is:
5. The delayed fluorescent material-assisted layer-by-layer deposition organic photovoltaic device according to claim 1, characterized in that: The substrate is a transparent glass substrate; the material of the conductive anode is indium tin oxide; the material of the anode modification layer is PEDOT:PSS; the material of the cathode modification layer is PNDIT-F3N; and the material of the metal cathode is Ag.
6. A method for preparing a delayed fluorescent material-assisted layer-by-layer deposition type organic photovoltaic device, characterized in that: The following steps are involved: providing a substrate and forming a conductive anode on the substrate; Spin coating an anode modification material on the conductive anode to form an anode modification layer; Spin-coating a donor film on the anode modification layer to form an electron donor layer; the donor film is a wide bandgap polymer donor PM1 material doped with a delayed fluorescence additive BN-STO; Spin coating an acceptor film on the electron donor layer to form an electron acceptor layer; the acceptor film is a non-fullerene small molecule acceptor L8-BO material doped with a solid additive trichlorobenzene; spin coating a cathode modification material on the electron acceptor layer to form a cathode modification layer; A metal cathode is formed by evaporating on the cathode modification layer.
7. The method for preparing a delayed fluorescent material-assisted layer-by-layer deposition type organic photovoltaic device according to claim 6, characterized in that: The preparation process of the wide bandgap polymer donor PM1 material doped with the delayed fluorescence additive BN-STO includes the following steps: Dissolve PM1 in chloroform and stir to dissolve to obtain a PM1 solution; the concentration of the PM1 solution is 7 mg / ml to 9 mg / ml; Dissolve BN-STO in chloroform and stir to dissolve to obtain a BN-STO solution; the concentration of the BN-STO solution is 0.003 mg / ml to 0.005 mg / ml; The BN-STO solution and the PM1 solution were mixed to obtain a PM1:BN-STO mixed solution; the volume ratio of the BN-STO solution to the PM1 solution was 1:0.01; and the mass ratio of the BN-STO to the PM1 was 1:0.
005.
8. The method for preparing a delayed fluorescent material-assisted layer-by-layer deposition type organic photovoltaic device according to claim 7, characterized in that: The concentration of the PM1 solution is 8 mg / ml; the concentration of the BN-STO solution is 0.004 mg / ml.
9. The method for preparing a delayed fluorescent material-assisted layer-by-layer deposition type organic photovoltaic device according to claim 6, wherein: The preparation process of the non-fullerene small molecule receptor L8-BO material doped with a solid additive trichlorobenzene comprises the following steps: L8-BO and trichlorobenzene were dissolved in chloroform at a ratio of 1:1.25, and stirred to dissolve to obtain an L8-BO receptor layer solution; the concentration of L8-BO in the L8-BO receptor layer solution was 7 mg / ml to 9 mg / ml, and the concentration of trichlorobenzene was 8.75 mg / ml to 11.25 mg / ml.
10. The method for preparing a delayed fluorescent material-assisted layer-by-layer deposition type organic photovoltaic device according to claim 6, characterized in that: The substrate is a transparent glass substrate; the material of the conductive anode is indium tin oxide; the anode modification material is PEDOT:PSS; the cathode modification material is PNDIT-F3N; and the material of the metal cathode is Ag.