An organic solar cell prepared by a layer-by-layer spin coating method, a preparation method and a method for measuring the influence of the same on device performance

Abstract

The application discloses an organic solar cell prepared by a layer-by-layer spin coating method, a preparation method and a method for measuring the influence of the organic solar cell on device performance. The device comprises a conductive base material, a hole transport layer, a donor material, an acceptor material, an electron transport layer and a cathode material. The preparation method comprises the following steps: firstly, spin coating a hole transport material layer on a clean conductive base material; spin coating an organic solution of the donor material on the hole transport layer; spin coating an organic solution of the acceptor material on the obtained donor thin film; performing heat annealing at 100 DEG C for 1 min; dissolving an electron transport layer in an organic solvent and spin coating the obtained thin film layer; and adopting a vacuum evaporation method to evaporate a cathode material as a cathode, so as to obtain the organic solar cell. The application optimizes the energy conversion efficiency of the device by adopting simple rotation speed adjustment without introducing an additive, thereby breaking the dependence on the additive in the prior art and simplifying the device preparation process.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of solar cell preparation, and in particular to an organic solar cell prepared by a layer-by-layer spin coating method, a preparation method, and a method for measuring the influence of the organic solar cell on device performance. BACKGROUND

[0002] At present, the efficiency of a single-junction organic solar cell based on a bulk heterojunction structure (BHJ) can exceed 18%, and a ternary organic solar cell can reach 19%, and the efficiency has reached a level that is commercially viable. In a BHJ device, due to the difficulty in predicting the thermodynamics and kinetics of the donor material and the acceptor material, it is difficult to balance the self-aggregation and compatibility inside the device prepared by one-step spin coating (BC device). Therefore, it is difficult to predict and control the film morphology generated thereby, especially the distribution of the donor and acceptor materials in the vertical direction in the BC film, which is closely related to the transmission and collection of charges. So far, how to form an ideal vertical phase separation is still a topic of concern.

[0003] Therefore, the organic solar cell prepared by the layer-by-layer spin coating method (SD device) can obtain a device with a good vertical phase separation structure. The independent spin coating of the acceptor material can adjust the morphology of the organic solar cell in the vertical direction, and the good vertical phase separation structure has a suitable D / A interface and a direct transmission path, which is conducive to the separation and extraction of charges, and is expected to obtain excellent photovoltaic performance parameters.

[0004] At present, the SD device prepared by the layer-by-layer spin coating method has obtained a relatively high energy conversion efficiency (PCE) by using different additives. However, there are still problems: 1. Further improving the PCE of the device; 2. Simplifying the device preparation process and using simple speed adjustment to optimize the device performance; 3. Exploring the influence of the changes of various parameters of the device on the PCE in the speed adjustment process. Therefore, it is necessary to carefully study the superiority of the SD device over the BC device; in the speed adjustment process, understand the various factors affecting the performance of the device, propose the concept of balancing parameter (ω), establish the quantitative relationship between ω and PCE, and be conducive to explaining the rules of the performance change of the SD device.

[0005] Through retrieval, the following two patent publications related to the present patent application are found:

[0006] 1. A planar heterojunction perovskite solar cell and its preparation method (CN105280819A), from bottom to top in turn are transparent conductive electrode, electron transport layer, perovskite light absorption layer, hole transport layer, metal electrode, the electron transport layer is TiO2 dense layer, the material of the peroviskite light absorption layer is chloride ion doped peroviskite material.The invention discards the TiO2 mesoporous layer in the traditional sensitized solar cell, simplifies the device structure and preparation process;The invention uses chloride doped peroviskite material as light absorption material, which helps to improve the film forming property of the thin film, and promotes the diffusion and separation of carriers;The invention proposes oxygen plasma treatment process for the surface treatment of transparent conductive electrode and TiO2 dense layer, which improves the film forming effect;The invention uses layer-by-layer spin coating process to control the thickness of peroviskite light absorption layer, which can realize the regulation and control of the photoelectric performance of light absorption layer and overall cell.

[0007] 2. A quantum dot solar cell and its preparation method (CN108172690A), the device includes glass substrate, cathode, electron transport layer, quantum dot light absorption layer, hole transport layer and anode;The quantum dot light absorption layer is a CsPbI3 thin film with cubic phase perovskite structure, the size of CsPbI3 quantum dots is 1-20 nanometers, and the thickness of the thin film is 20-800 nanometers;The hole transport layer is an organic conjugated polymer thin film, such as P3HT, PTB7, PTB7-Th, etc., and the thickness of the thin film is 10-200 nanometers.The invention uses organic conjugated polymer as hole transport material, which has excellent hole transport capacity without doping;At the same time, the organic conjugated polymer thin film has strong water resistance due to its chemical structure, which improves the photoelectric conversion efficiency and air stability of the quantum dot solar cell.The quantum dot solar cell provided by the invention has the characteristics of simple preparation process and high repeatability.

[0008] By comparison, the patent application of the invention and the above patent disclosure have essential differences. SUMMARY

[0009] The present invention aims to overcome the deficiencies in the prior art, and provides an organic solar cell prepared by layer-by-layer spin coating method, a preparation method and a method for measuring its effect on device performance.

[0010] The technical solution adopted by the present invention to solve its technical problems is:

[0011] An organic solar cell device prepared by layer-by-layer spin coating method, the device includes conductive base material, hole transport layer, donor material, acceptor material, electron transport layer and cathode material.

[0012] The conductive substrate material is selected from any one of indium tin oxide (ITO) glass, fluorine-doped tin dioxide glass, aluminum-doped zinc oxide glass, ITO-polyethylene terephthalate, ITO-polyethylene naphthalate or a combination thereof;

[0013] The hole transport material is selected from any one of poly 3,4-ethylenedioxythiophene or polystyrene sulfonate or a combination thereof;

[0014] The donor material is selected from any one of D18, PM6, PM7 or a combination thereof;

[0015] The acceptor material is selected from any one of L8-BO, N3, Y6 or a combination thereof;

[0016] The electron transport layer is selected from any one of PDIN, PDINN, PDINO or a combination thereof;

[0017] The cathode material is selected from conductive materials or inert electrode materials, including silver, iron, copper, aluminum, gold, platinum or graphite.

[0018] A method for preparing an organic solar cell device as described above, comprising the following steps:

[0019] (1) First spin-coat a layer of hole transport material on a clean conductive substrate material;

[0020] (2) Spin-coat an organic solution of donor material on the hole transport layer at a speed ranging from 1000 to 1500 rpm;

[0021] (3) Spin-coat an organic solution of acceptor material on the donor thin film obtained in step (2) at a speed ranging from 2500 to 4500 rpm to obtain an active layer thin film;

[0022] (4) Heat-anneal the active layer thin film at 100°C for 1 min;

[0023] (5) Dissolve the electron transport layer in an organic solvent and spin-coat it on the thin film layer obtained in step (4);

[0024] (6) Use vacuum evaporation method to evaporate the cathode material as the cathode to obtain an organic solar cell.

[0025] Further, the organic solvent in step (2) is one or a combination of chlorobenzene, toluene or xylene.

[0026] Further, the organic solvent in step (3) is selected from one or a combination of chloroform, carbon tetrachloride, dichloromethane.

[0027] Further, the organic solvent in step (5) is selected from methanol and acetic acid.

[0028] Further, the concentration of the donor material in the organic solution of the donor material in step (2) is 7 mg / mL; and the concentration of the acceptor material in the organic solution of the acceptor material in step (3) is 9 mg / mL.

[0029] A method for measuring the influence of a device preparation method on the performance of an organic solar cell device, wherein a balance parameter omega is selected as a reference value, and the expression of the balance parameter omega is:

[0030]

[0031] wherein V loss is the voltage loss, G is the exciton generation rate, P diss is the exciton dissociation rate, P coll is the exciton collection rate.

[0032] A quantitative relationship between the balance parameter omega and the PCE of the organic solar cell is established:

[0033] PCE = -5.7280 + 9.2924 omega

[0034] Adj. R-Square = 0.9264

[0035] The above relationship shows that for different devices, the larger the corresponding balance parameter omega, the larger the PCE of the device.

[0036] The organic solar cell device is the organic solar cell device described above.

[0037] The advantages and positive effects obtained by the present application are:

[0038] 1. The present application optimizes the energy conversion efficiency of the device by using simple speed regulation without the need to introduce additives, thereby simplifying the device preparation process and eliminating the dependence on additives in the prior art.

[0039] 2. The efficiency of the organic solar cell device based on the D18 / L8-BO system in the present application is 19.05%, which is the highest PCE value for a binary organic solar cell, and this efficiency is better than the efficiency value (18.14%) of the corresponding BC device.

[0040] 3. The present application proposes the concept of a balance parameter (omega), and establishes a quantitative relationship between the balance parameter and the energy conversion efficiency of the cell (omega-PCE), wherein the balance parameter is used as an evaluation index to evaluate the influence of the preparation process on the performance of the device, which is beneficial to explain the change rule of the device performance with the preparation process. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1Device I-V curve of Example 1 in the present application;

[0042] Figure 2 Voltage loss schematic diagram of Example 2 in the present application;

[0043] Figure 3 J-V curve of Example 2 in the present application; ph -V eff curve of Example 2 in the present application.

[0044] Figure 4 Quantitative relationship curve of equilibrium parameter (ω) and energy conversion efficiency (PCE) of Example 2 in the present application. DETAILED DESCRIPTION

[0045] The following describes the embodiments of the present application in detail, and it should be noted that the embodiments are described and are not limiting, and cannot limit the protection scope of the present application.

[0046] The raw materials used in the present application are conventional commercially available products, unless otherwise specified; the methods used in the present application are conventional methods in the art, unless otherwise specified.

[0047] An organic solar cell device prepared by a layer-by-layer spin coating method, the device comprising a conductive base material, a hole transport layer, a donor material, an acceptor material, an electron transport layer and a cathode material;

[0048] The conductive base material is selected from any one or a combination of indium tin oxide (ITO) glass, fluorine-doped tin dioxide glass, aluminum-doped zinc oxide glass, ITO-polyethylene terephthalate, ITO-polyethylene naphthalate;

[0049] The hole transport material is selected from poly 3,4-ethylenedioxythiophene or polystyrene sulfonate or a combination thereof;

[0050] The donor material is selected from any one or a combination of D18, PM6, PM7;

[0051] The acceptor material is selected from any one or a combination of L8-BO, N3, Y6;

[0052] The electron transport layer is selected from any one or a combination of PDIN, PDINN, PDINO;

[0053] The cathode material is selected from conductive materials or inert electrode materials, including silver, iron, copper, aluminum, gold, platinum or graphite.

[0054] A preparation method of the organic solar cell device as described above, comprising the following steps:

[0055] (1) first spin-coating a layer of hole transport material on a clean conductive substrate material;

[0056] (2) spin-coating an organic solution of donor material on the hole transport layer at a speed ranging from 1000 to 1500 rpm;

[0057] (3) spin-coating an organic solution of acceptor material on the donor film obtained in step (2) at a speed ranging from 2500 to 4500 rpm to obtain an active layer film;

[0058] (4) heat annealing the active layer film at 100°C for 1 min;

[0059] (5) dissolving an electron transport layer in an organic solvent and spin-coating it on the film layer obtained in step (4);

[0060] (6) vacuum evaporation of a cathode material as a cathode to obtain an organic solar cell.

[0061] Preferably, the organic solvent in step (2) is one or a combination of several of chlorobenzene, toluene or xylene.

[0062] Preferably, the organic solvent in step (3) is selected from one or a combination of several of chloroform, carbon tetrachloride or dichloromethane.

[0063] Preferably, the organic solvent in step (5) is selected from methanol and acetic acid.

[0064] Preferably, the concentration of the donor material in the organic solution of the donor material in step (2) is 7 mg / mL; and the concentration of the acceptor material in the organic solution of the acceptor material in step (3) is 9 mg / mL.

[0065] A method for measuring the influence of a device preparation method on the performance of an organic solar cell device, wherein a parameter selected from the method is used as a reference value, and the expression of the parameter is:

[0066]

[0067] wherein V loss is the voltage loss, G is the exciton generation rate, P diss is the exciton dissociation rate, P coll is the exciton collection rate.

[0068] A quantitative relationship between the equilibrium parameter ω and the PCE of an organic solar cell is established:

[0069] PCE = -5.7280 + 9.2924ω

[0070] Adj. R-Square = 0.9264

[0071] The above relationship shows that for different devices, the greater the corresponding balance parameter ω, the greater the PCE of the device; wherein the organic solar cell device is the above organic solar cell device.

[0072] Specifically, the related preparation and detection embodiments are as follows:

[0073] In order to simplify the device preparation process, a simple rotational speed adjustment is used to prepare the SD device by layer-by-layer spin coating of the donor and acceptor materials, and the influence of the device preparation process on various parameters of the device performance is studied. The donor and acceptor materials are spin-coated in turn to form a good vertical phase separation structure. Through the study of energy loss (E loss ), exciton generation rate (G), exciton dissociation rate (P diss ) and charge collection rate (P coll ), the concept of balance parameter (ω) is proposed, and the quantitative relationship between the balance parameter and the energy conversion efficiency (PCE) is established, and the law of the influence of the device preparation process on the device performance is clarified.

[0074] Example 1

[0075] Preparation of organic solar cell (SD device) by layer-by-layer spin coating method:

[0076] A plurality of ITO glasses with a square resistance of about 20 ohms / square and a size of 15 mm x 15 mm square pieces. Respectively, they are ultrasonically cleaned in detergent, deionized water, acetone, and anhydrous ethanol for 30 min. Before use, the ITO glass is blown dry under the condition of nitrogen and placed in a plasma cleaning machine for cleaning for 1 min. The hole transport layer PEDOT:PSS (Clevios P VPAl 4083) is spin-coated at a rotational speed of 3000 rpm for 30 s, and annealed at 150°C for 15 min, and then transferred to a glove box for standby. The chlorobenzene solution of the donor material is spin-coated on the hole transport layer. Then, the chloroform solution of the acceptor material is spin-coated on the donor film, and the film is annealed at a temperature of 100°C for 1 min. The electron transport layer is selected to be PDIN with a concentration of 2 mg / mL, and is spin-coated at a speed of 5000 rpm for 30 s. Finally, a vacuum evaporation method is used to evaporate Ag electrode as the cathode.

[0077] Figure 1 The I-V curve of the device in Example 1 is shown in the figure. As shown, the open-circuit voltage (V oc ) of the BC device is 0.911 V, the short-circuit current (J sc ) is 26.31 mA / cm 2 , the fill factor (FF) is 75.67%, and the PCE is 18.14%. The open-circuit voltage (V oc ) of the optimal SD device is 0.918 V, the short-circuit current (J scThe value is 26.86 mA / cm. 2 The fill factor (FF) was 77.25% and the PCE was 19.05%. As shown in Table 1, the PCE of the binary SD device based on D18 / L8-BO film prepared by layer-by-layer spin coating has exceeded 19% for the first time. This efficiency is higher than the PCE value reported in other literature, and this performance is significantly better than its corresponding BC device, indicating the advantages of SD device.

[0078] Table 1 Comparison of the performance of the binary components in this work with those in other works.

[0079]

[0080] Example 2

[0081] Mechanism explanation:

[0082] During device fabrication, different spin-coating speeds result in varying performance of the SD device. High device efficiency requires simultaneously meeting high-quality Vo requirements. oc J sc FF. For example Figure 2 As shown, for V oc The device needs to have a low voltage drop (E loss =E g –qV oc );like Figure 3 As shown, for J sc The device needs to have a high exciton generation rate (G) and exciton dissociation rate (P). diss );like Figure 3 As shown, for FF, the device needs to have a high charge collection rate (P). coll Therefore, in order to comprehensively consider the influence of various parameters on device performance, the concept of a balance parameter ω is proposed, and its expression is:

[0083]

[0084] V of different devices loss G, P diss P coll The PCE of the devices is shown in Table 2. Figure 4As shown, ω has a good linear relationship with PCE: PCE = -5.7280 + 9.2924ω (wherein Adj. R-Square = 0.9264). In which, the balance parameter of BC device is 2.5562, and the corresponding PCE is 18.14%. In the SD device, by changing the spin speed of the spin-coated acceptor material, the corresponding PCE value presents difference. This is because after the speed adjustment, a series of changes occur in the voltage loss, exciton generation rate, exciton dissociation rate, and charge collection rate inside the device. Therefore, in order to comprehensively consider the influence of a series of changes on the performance of the device, the concept of balance parameter is proposed. The optimal SD device has the largest ω value of 2.6784, so it shows the highest PCE value. From the linear relationship between ω and PCE, the larger the ω value, the larger the PCE value, and the optimal SD device has the largest ω value and obtains outstanding performance. Therefore, the linear relationship between ω and PCE comprehensively explains the influence of the changes of various parameters inside the device on the performance of the device.

[0085] Table 2 V loss , G, P diss , P coll and the PCE of the device.

[0086]

[0087] Although the embodiments of the present application are disclosed for illustrative purposes, those skilled in the art can understand that various alternatives, changes and modifications are possible without departing from the spirit and scope of the present application and the appended claims, therefore, the scope of the present application is not limited to the disclosed content of the embodiments.

Claims

1. An organic solar cell device prepared by layer-by-layer spin coating method, said device comprising a conductive substrate material, a hole transporting layer, a donor material, an acceptor material, an electron transporting layer and a cathode material; characterized in that: the conductive substrate material is selected from any one or a combination of indium tin oxide glass, fluorine-doped tin dioxide glass, aluminum-doped zinc oxide glass, ITO-polyethylene terephthalate, ITO-polyethylene naphthalate; the hole transporting material is selected from poly 3,4-ethylenedioxythiophene or polystyrene sulfonate or a combination thereof; the donor material is selected from D18; the acceptor material is selected from L8-BO; the electron transporting layer is selected from any one or a combination of PDIN, PDINN; the cathode material is selected from conductive materials or inert electrode materials, including silver; the method for preparing said organic solar cell device comprises the following steps: (1) first spin coating a layer of hole transporting material on a clean conductive substrate material; (2) spin coating an organic solution of donor material on the hole transporting layer at a speed ranging from 1000 to 1500 rpm; (3) spin coating an organic solution of acceptor material on the donor thin film obtained in step (2) at a speed ranging from 2500 to 4500 rpm to obtain an active layer thin film; (4) annealing the active layer thin film at 100°C for 1 min; (5) dissolving the electron transporting layer in an organic solvent and spin coating on the thin film layer obtained in step (4); (6) vacuum evaporation of the cathode material as a cathode to obtain an organic solar cell; the organic solvent in step (2) is one or a combination of chlorobenzene, toluene or xylene; the organic solvent in step (3) is selected from one or a combination of chloroform, carbon tetrachloride, dichloromethane; the organic solvent in step (5) is selected from methanol and acetic acid; the concentration of the donor material in the organic solution of the donor material in step (2) is 7 mg / mL; the concentration of the acceptor material in the organic solution of the acceptor material in step (3) is 9 mg / mL.

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