Inherently stretchable fibrous solar cells and methods of making the same

Abstract

The present application relates to a kind of intrinsic stretchable fibrous solar cell and its preparation method, the scheme includes the following steps: using elastic fiber as intrinsic stretchable elastic fiber base;The substrate is pre-stretched, and is fixed on traction coating mechanism;Highly conductive coating is sequentially and uniformly coated on the substrate by traction coating mechanism, to obtain intrinsic stretchable fibrous conductive substrate electrode;Preparation electron transport layer solution, and uniformly coated on electrode by traction coating machine;Preparation light absorption layer solution, and uniformly coated on electron transport layer;Preparation hole transport layer solution, and uniformly coated on light absorption layer to obtain working electrode;Counter electrode is wound on working electrode to form biaxial winding structure.The present application solves the existing stretchable fiber battery existing device performance lower, the problem of poor stretchability, stretchability is not recoverable.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fibrous solar cells, in particular to intrinsically stretchable fibrous solar cells and a preparation method thereof. BACKGROUND

[0002] In recent years, wearable electronic devices that can be directly worn on the human body or fabric have developed rapidly, thereby putting forward higher requirements for their energy supply systems, such as light weight, small size, high flexibility and adaptability to frequent deformation.

[0003] One-dimensional fibrous solar cells can be woven into breathable textiles with electrochemical properties matching wearable electronic devices while maintaining high performance, showing great application potential in the field of wearable electronic devices. However, the fibrous batteries currently studied can generally meet the requirement of flexibility, but it is difficult to adapt to various high-frequency and complex deformations of the human body. Stretchable fibrous batteries can effectively solve the above problems. However, there are few studies on stretchable fibrous batteries at present, which is mainly limited by the intrinsically stretchable fibrous conductive substrate electrode. The fibrous batteries currently used basically adopt hard conductive metal wires as the substrate electrode, which has a certain flexibility but does not have stretchable performance.

[0004] In view of the above situation, the current method is to ensure the conductivity while realizing a certain stretchability through a compromise, that is, to realize the stretchability through structural deformation, which is to continuously spiral the metal wire, to make it into a spring structure through external deformation, and then to coat each functional material based on the spring structure, and finally to assemble with the counter electrode to form a certain structural stretchable fibrous battery. Based on this structural deformation, the fibrous battery has stable stretchability within a small deformation range, but when the deformation is slightly large (such as > 30%), the battery device will lose elasticity due to the large deformation and cannot recover to the original length. Moreover, the stretchability given by this structural deformation is low, and when facing high deformation, it loses the recovery ability and cannot be reused, which is not suitable for application in complex and high-frequency deformation wearable devices. In addition, the photoelectric conversion efficiency of the fibrous battery device based on this spring structure is generally low (such as the highest efficiency of stretchable organic fibrous battery is 1.23%, and the average efficiency is 0.7%), which is difficult to be used for power supply of wearable devices.

[0005] At the same time, even if the problem of intrinsically stretchable conductive substrate is solved, it is also challenging to make the prepared stretchable fibrous battery have high photoelectric conversion efficiency.

[0006] Therefore, there are still great challenges in the field of fibrous solar cells in terms of maintaining high device performance while stretching. SUMMARY

[0007] The present application aims to provide an intrinsically stretchable fiber-shaped solar cell and a preparation method thereof to solve the above problems in the prior art.

[0008] To achieve the above-mentioned application purposes, the present application adopts the following technical solutions: the preparation method of the intrinsically stretchable fiber-shaped solar cell comprises the following steps:

[0009] The elastic fiber is used as the intrinsically stretchable conductive fiber substrate;

[0010] The intrinsically stretchable fiber substrate is pre-stretched and fixed on a traction coating mechanism;

[0011] The high-conductivity coating is uniformly coated on the intrinsically stretchable fiber substrate by the traction coating mechanism, and after the coating is completed, the intrinsically stretchable fiber substrate is placed in a room temperature drying to obtain an intrinsically stretchable fiber-shaped conductive substrate electrode;

[0012] An electron transport layer solution is prepared and uniformly coated on the intrinsically stretchable fiber-shaped conductive substrate electrode by the traction coating mechanism;

[0013] An optical absorption layer solution is prepared and uniformly coated on the electron transport layer by the traction coating mechanism;

[0014] A hole transport layer solution is prepared and uniformly coated on the optical absorption layer by the traction coating mechanism to obtain a working electrode;

[0015] The counter electrode is wound on the working electrode to form a biaxial winding structure to obtain the intrinsically stretchable fiber-shaped solar cell;

[0016] The coating of the high-conductivity coating and each functional layer is performed on the premise that the intrinsically stretchable conductive fiber substrate has been pre-stretched and kept in the stretched state.

[0017] Further, the intrinsically stretchable conductive fiber substrate is pre-stretched by at least 0-500% before the high-conductivity coating is coated.

[0018] Further, the high-conductivity coating comprises Ag NWs dispersion liquid and ITO NPs dispersion liquid. It can also be dispersion liquid of other high-conductivity materials.

[0019] Further, the Ag NWs dispersion liquid is coated multiple times to ensure the conductivity.

[0020] Further, the concentration of the Ag NWs dispersion liquid is 1-20 mg / mL, and the concentration of the ITO NPs dispersion liquid is 0.1-5 wt%.

[0021] Further, the surface of the elastic fiber is cleaned, dried, i.e. plasma treated, before the high-conductivity layer is coated.

[0022] Further, the electron transport layer solution comprises at least one of PDINO, ZnO nanocrystals, ZnO nanoparticles and TiO2 dense film, and the raw material of the light absorption layer solution comprises an organic photovoltaic material.

[0023] Further, the total concentration of the light absorption layer solution is 1-50 mg / mL.

[0024] Further, the stretchable fiber-shaped conductive substrate electrode is subjected to a stretchability test, and the resistance change under different stretching conditions is recorded.

[0025] Further, the prepared intrinsic stretchable fiber-shaped solar cell is subjected to a stretchability test, and the photovoltaic performance change under different stretching conditions is recorded.

[0026] The intrinsic stretchable fiber-shaped solar cell is prepared by the above method.

[0027] Beneficial effects: 1. Compared with the flexible concept of the prior art, the present application proposes a new concept of stretchability, which is different from the flexible concept. At the same time, it is because of the new concept of stretchability that the prepared fiber battery has the characteristics of high performance and good stretchability under the premise of intrinsic stretchability, thereby solving the problems of low device performance, poor stretchability and non-recoverable stretchability of the existing stretchable fiber battery;

[0028] 2. Compared with the prior art, the prepared substrate electrode can maintain a resistance lower than 20 Ω·cm -1 under a stretching of 60%, and maintain high conductivity under a stretching deformation of more than 200%. The battery prepared based on the substrate electrode has high photoelectric conversion efficiency, and can maintain more than 92%, 90%, 89% and 76% of the initial performance under a stretching of 10%, 20%, 30% and 40%, respectively. Moreover, the intrinsic stretchable deformation is recoverable. Specifically, after the stress of 30% stretching deformation is released, the battery can quickly recover to the original length, and the device performance can also recover more than 95% of the initial performance. The fiber battery has good durability and stability, and can be repeatedly stretched 1000 times under a stretching deformation of 10%, and the device can maintain more than 80% of the photoelectric conversion performance. Even under a deformation of 30%, it can be repeatedly stretched for about 100 times. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a flowchart of the method of the present application;

[0030] Figure 2Preparation and structural schematic diagram of the intrinsically stretchable fiber-shaped solar cell provided by the present application;

[0031] Figure 3 Resistance change diagram of the fiber electrode prepared by the present application with different degrees of “pre-stretching” at different tensile strains;

[0032] Figure 4 Resistance change diagram of the fiber electrode prepared by the present application with different structures at 60% tensile strain after 5 times of stretching-recovery cycles;

[0033] Figure 5 Resistance change diagram of the intrinsically stretchable fiber electrode prepared by the present application at 30% tensile strain after repeated stretching for more than 20000 times;

[0034] Figure 6 Photoelectric conversion efficiency diagram of the intrinsically stretchable fiber-shaped solar cell prepared by the present application;

[0035] Figure 7 Device performance change diagram of the intrinsically stretchable fiber-shaped solar cell prepared by the present application after stretching to different degrees after pre-stretching;

[0036] Figure 8 Performance curve diagram of the intrinsically stretchable fiber-shaped solar cell prepared by the present application before and after 30% tensile strain;

[0037] Figure 9 Real-time change diagram of the photo-generated current of the intrinsically stretchable fiber-shaped solar cell prepared by the present application during stretching;

[0038] Figure 10 Device performance diagram of the intrinsically stretchable fiber-shaped solar cell prepared by the present application after repeated stretching for 300 and 500 times;

[0039] Figure 11 Performance change diagram of the intrinsically stretchable fiber-shaped solar cell prepared by the present application after repeated stretching for 1000 times at 10% strain;

[0040] Figure 12 Long-term stability diagram of the intrinsically stretchable fiber-shaped solar cell prepared by the present application under different stretching states. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art belong to the scope of protection of the present application.

[0042] Those skilled in the art should understand that, in the disclosure of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limiting this invention.

[0043] like Figure 1 As shown, the method for fabricating an intrinsically stretchable fibrous solar cell includes the following steps:

[0044] S00. Using elastic fiber as the intrinsically stretchable conductive fiber substrate, the intrinsically stretchable elastic fiber substrate is pre-stretched and fixed on the traction coating mechanism.

[0045] In this embodiment, TPU polyurethane elastic fibers with a diameter of 0.1–0.8 mm are used as the core of the intrinsically stretchable fiber electrode. The fibers are ultrasonically cleaned for 1–30 minutes in deionized water, deionized water containing detergent, and ethanol solution, respectively. After cleaning, they are dried in air or a nitrogen atmosphere. Finally, the TPU fiber surface is subjected to plasma treatment to improve its wettability. After treatment, the treated elastic fibers are fixed on a traction coating mechanism, and a tensile strain of 0–100% is applied (hereinafter referred to as pre-stretching, i.e., pre-stretched to a certain degree; of course, it can also be stretched to 500%, the degree of stretching is set according to the material properties, and this application does not limit it).

[0046] The range of stretching depends on the requirements and is not limited here.

[0047] The traction coating mechanism uses a motor to pull the intrinsically stretchable elastic fiber substrate to move through the coating hole to achieve the coating operation. This mechanism is the traction coating mechanism disclosed by the inventor in the previously filed patent CN113594371A. Its structure, principle and operation will not be described in detail here.

[0048] The high conductivity coating and the various functional layers (electron transport layer, light absorption layer, and hole transport layer, etc.) are applied after the intrinsically stretchable conductive fiber substrate has been pre-stretched and maintained in a stretched state. Furthermore, the strain is not released before each coating; it is released only after all coating layers have been applied. In other words, the intrinsically stretchable conductive fiber substrate must be pre-stretched and maintained in a stretched state before each coating is applied, and the substrate can only be removed and the strain released after coating is complete. Preferably, the strain is released only after all functional layers have been coated.

[0049] S10, coating the high-conductive coating layer on the intrinsic stretchable elastic fiber substrate by traction coating mechanism, and drying the intrinsic stretchable fiber-shaped conductive substrate electrode at room temperature after coating is completed;

[0050] The high-conductive coating layer solution includes Ag NWs dispersion liquid and ITO NPs dispersion liquid and other high-conductive material dispersion liquids. The Ag NWs dispersion liquid is prepared by dispersing Ag NWs in ethanol solution, and the dispersion liquid concentration is 1-20 mg / mL, and physical dispersion is performed before each use. The ITO NPs dispersion liquid is prepared by dispersing ITO NPs in isopropyl alcohol solution, and the concentration is 0.1-5 wt%, and physical dispersion is performed before each use.

[0051] In this embodiment, the high-conductive Ag NWs and ITO NPs are uniformly coated on the surface of the TPU fiber by mechanical coating, and the coating speed is set to 100-5000 mm / min. The above steps can be repeated 0-15 times to ensure sufficient conductivity. After each coating is completed, the intrinsic stretchable fiber-shaped conductive substrate electrode is naturally dried at room temperature.

[0052] Preferably, the prepared intrinsic stretchable fiber-shaped conductive substrate electrode can also be subjected to a tensile property test, and the resistance change under different tensile conditions is recorded.

[0053] In this way, the intrinsic stretchable fiber-shaped conductive substrate electrode can also be removed to release the pre-tension strain and restore to the original length (if the subsequent active layer is also pre-stretched to the same degree, this operation can be omitted).

[0054] S20, preparing an electron transport layer solution and uniformly coating the electron transport layer solution on the intrinsic stretchable fiber-shaped conductive substrate electrode by traction coating mechanism;

[0055] The electron transport layer solution at least includes PDINO, ZnO nanocrystals, ZnO nanoparticles, and TiO2 dense film.

[0056] For example, the PDINO is dissolved in methanol to obtain an electron transport layer solution with a concentration of 1-40 mg / mL.

[0057] In this embodiment, the intrinsic stretchable fiber-shaped conductive substrate electrode is first pre-stretched by 0-100%. The PDINO electron transport layer solution is prepared at the same time, and the electron transport layer solution is uniformly coated at a speed of 100-5000 mm / min, and the solution concentration is 1-50 mg / mL.

[0058] S30, preparing an optical absorption layer solution and uniformly coating the optical absorption layer solution on the electron transport layer by traction coating mechanism.

[0059] The raw materials for the light-absorbing layer solution include one or more of organic photovoltaic materials, perovskite materials, and dye-sensitized materials; such as PM6, Y6, and PC. 71 Both BM and Y6 are soluble in chloroform, chlorobenzene, or a mixture of both. The three organic semiconductor materials are mixed in a mass ratio. Assuming PM6 has a mass of 1, the mass range of Y6 is 0.5–10, and the mass range of PCBM is 0.05–0.5. The total mass concentration of the solution is 5–40 mg / mL. This yields the light-absorbing layer solution.

[0060] In this embodiment, PM6:Y6:PCBM ternary organic photovoltaic material is uniformly coated at a coating speed of 100-5000 mm / min, and the total concentration of the mixed solution is 1-50 mg / mL.

[0061] S40. Prepare a hole transport layer solution and uniformly coat it onto the light-absorbing layer using a traction coating mechanism;

[0062] The hole transport layer solution can be made of materials such as PEDOT:PSS, for example, the concentration of PEDOT:PSS solution is 0.1-2 wt%.

[0063] In this embodiment, a hole transport layer is formed by using materials such as PEDOT:PSS as the hole transport layer and coating the hole transport layer at a coating speed of 100 to 5000 mm / min to obtain the working electrode of a stretchable fiber solar cell.

[0064] S50, such as Figure 2 As shown, the counter electrode is wound around the working electrode to form a biaxial winding structure, resulting in an intrinsically stretchable fibrous solar cell.

[0065] The counter electrode is made of carbon nanotubes with a diameter of 0.01–0.2 mm, silver wire, or copper wire.

[0066] S60. Perform tensile property tests on the intrinsically stretchable fibrous conductive substrate electrode and record the resistance changes under different tensile conditions.

[0067] S70. Perform tensile performance tests on the prepared intrinsically stretchable fibrous solar cells and record the changes in tensile performance and photovoltaic performance under different stretching conditions.

[0068] Preferably, steps S60-S70 can be performed simultaneously or sequentially.

[0069] In this embodiment, the tensile property testing system (prior art, common experimental equipment, not limited here) used uses a high-precision numerical control sliding table with clamps to characterize the tensile properties of the stretchable conductive fiber substrate and the fibrous solar cell. The two ends of the fiber are fixed on two clamps, respectively. Through the program control system, the corresponding program is set, and the tensile properties under different conditions can be accurately measured, such as single strain, multiple cycle strain, and incremental strain. The specific testing method is prior art.

[0070] In this embodiment, the resistance change of the fiber electrode during the stretching process is characterized in real time by Keithley 2400 digital source table. Using a solar simulator (Newport, M94043A), AM1.5G, 100mW / cm 2 The photovoltaic performance of the battery is tested by combining the Keithley 2400 digital source table with the photovoltaic testing system, and the J-V curve of the battery is obtained. Similarly, the photovoltaic testing system combined with the tensile property testing system can characterize the photovoltaic performance of the fibrous battery in real time during the stretching process, including the J-V curve under different stretching degrees, and the stretching strain-photocurrent curve.

[0071] In this way, the conductive material is coated on the surface of the elastic fiber TPU by the mechanical coating method, and the use of the "pre-stretching" strategy can significantly reduce the resistance during the stretching process, such as Figure 3 .

[0072] After preparing the Ag NWs conductive layer on the intrinsic stretchable TPU substrate, continue to coat and ITO NPs conductive layer, the combination of conductive nanowire network and nanoparticles can effectively reduce the resistance of the electrode during the stretching process, such as Figure 4 .

[0073] The prepared fiber electrode has good durability and stability, and the resistance only increases by 1 time after repeated stretching for more than 20000 times under 30% strain, such as Figure 5 .

[0074] The intrinsic stretchable fiber solar cell prepared by this embodiment has excellent photovoltaic performance, and the energy conversion efficiency is as high as 5.8%, such as Figure 6 .

[0075] The prepared fibrous solar cell device has excellent tensile properties, and the pre-stretching strategy effectively increases the tensile properties of the fibrous device from about 20% to more than 70%, such as Figure 7 .

[0076] The device tensile properties have good reversibility, and the performance of the stretched device remains basically unchanged, such as Figure 8 .

[0077] Real-time detection of the change of photo-generated current can directly reflect the change of photovoltaic performance of the fiber device during continuous stretching. Within a strain range of 40%, the photo-generated current of the device remains basically unchanged, as shown in Figure 9 .

[0078] The device has good mechanical stability. The device performance remains basically unchanged after repeated stretching for 300 and 500 times, as shown in Figure 10 ; after repeated stretching for 1000 times, it can still maintain more than 80% of the initial performance, as shown in Figure 11 .

[0079] Further study on the effect of stretching on the long-term stability of the fiber battery device shows that stretching within a small range basically does not affect the long-term stability of the device, while stretching to a larger extent is not conducive to the long-term stability of the device, as shown in Figure 12 .

[0080] The part of the present application not described in detail is the prior art, so the present application does not describe it in detail.

[0081] It can be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of one element can be one, and in another embodiment, the number of the element can be multiple, and the term "one" cannot be understood as a limitation on the number.

[0082] Although professional terms are used more in this paper, the possibility of using other terms is not excluded. The use of these terms is only to more conveniently describe and explain the essence of the present application; any interpretation of them as any kind of additional limitation is contrary to the spirit of the present application.

[0083] The present application is not limited to the above best embodiment, and anyone can derive other various forms of products under the inspiration of the present application, but regardless of any change in shape or structure, any technical solution with the same or similar to the present application falls within the protection scope of the present application.

Claims

1. A method for producing an intrinsically stretchable fibrous solar cell, characterized by, The method comprises the following steps: using elastic fiber as intrinsic stretchable fiber base, pre-stretching the intrinsic stretchable elastic fiber base, and fixing it on a traction coating mechanism; uniformly coating high-conductive coating on the intrinsic stretchable fiber base by the traction coating mechanism, and drying the intrinsic stretchable elastic fiber base at room temperature after coating to obtain an intrinsic stretchable fiber-like conductive base electrode; the high-conductive coating comprises Ag NWs dispersion liquid with a concentration of 1-20 mg / mL and ITO NPs dispersion liquid with a concentration of 0.1-5 wt%, and the Ag NWs dispersion liquid is coated multiple times to ensure conductivity; preparing an electron transport layer solution and uniformly coating it on the intrinsic stretchable fiber-like conductive base electrode by the traction coating mechanism; preparing an optical absorption layer solution and uniformly coating it on the electron transport layer by the traction coating mechanism; preparing a hole transport layer solution and uniformly coating it on the optical absorption layer by the traction coating mechanism to obtain a working electrode; winding a counter electrode on the working electrode to form a biaxial winding structure to obtain an intrinsic stretchable fiber-like solar cell; wherein the coating of the high-conductive coating and each functional layer is performed on the premise that the intrinsic stretchable conductive fiber base has been pre-stretched and kept in a stretched state.

2. The method of claim 1, wherein the intrinsic stretchable fiber-shaped solar cell is prepared by the steps of: The elastic fiber is first cleaned, dried and subjected to plasma treatment before being coated with the high-conductive layer.

3. The method for fabricating an intrinsically stretchable fibrous solar cell according to claim 1, characterized in that, The electron transport layer solution at least comprises one of PDINO, ZnO nanocrystals, ZnO nanoparticles and TiO2 dense film, and the raw material of the optical absorption layer solution at least comprises organic photovoltaic material.

4. The method of making a stretchable intrinsic fibrous solar cell of claim 1, wherein, The total concentration of the optical absorption layer solution is 1-50 mg / mL.

5. The method of making intrinsically stretchable fibrous solar cells according to any one of claims 1-4, wherein, The intrinsic stretchable fiber-like conductive base electrode is subjected to stretchability test, and the resistance change under different stretching conditions is recorded.

6. The method of claim 5, wherein the intrinsic stretchable fiber-shaped solar cell is prepared by the steps of: The intrinsic stretchable fiber-like solar cell prepared is subjected to stretchability test, and the stretchability and photovoltaic performance change under different stretching conditions are recorded.

7. A stretch-orientable fibrous solar cell characterized by The intrinsic stretchable fiber-like solar cell is prepared by the method of any one of claims 1-6.

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