Flexible perovskite photovoltaic device and preparation method thereof

Abstract

The embodiment of the invention provides a flexible perovskite photovoltaic device and a preparation method thereof. The flexible perovskite photovoltaic device comprises a perovskite photovoltaic cell layer; the water and oxygen barrier film layer at least covers the two sides of the perovskite photovoltaic cell layer, and a first water and oxygen barrier film and a second water and oxygen barrier film are formed on the two sides of the perovskite photovoltaic cell layer respectively; the elastic packaging layer coats the water-oxygen barrier film layer; the Young modulus of the above layer structure satisfies the following relation: the perovskite photovoltaic cell layer > the water oxygen barrier film layer > the elastic packaging layer. The thickness of the elastic packaging layer is larger than the thickness of the water-oxygen barrier film layer and larger than the thickness of the perovskite photovoltaic cell layer. According to the flexible perovskite photovoltaic device and the preparation method thereof provided by the embodiment of the invention, the appearance of the device or the surface of the water-oxygen barrier film is not damaged when the flexible perovskite photovoltaic device is bent for use, the photoelectric conversion efficiency is ensured, and the service life of the device is prolonged.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of perovskite, and particularly relates to a flexible perovskite photovoltaic device and a preparation method thereof. BACKGROUND

[0002] Perovskite solar photovoltaic devices are one of the most disruptive technologies in the field of solar energy in recent years. They use materials with perovskite crystal structure (usually organic-inorganic hybrid lead halide) as light-absorbing layers to convert light energy into electrical energy.

[0003] The current packaging method of rigid perovskite solar photovoltaic modules usually adopts the following method: sequentially performing electron or hole transport layer, perovskite light-absorbing layer, hole or electron transport layer, and upper electrode fabrication on a transparent conductive glass (lower electrode), and finally using an encapsulating adhesive film to adhere a cover glass on the top to complete the packaging of the rigid perovskite photovoltaic module. This rigid packaging method increases the weight and thickness of the solar photovoltaic module, which is not conducive to the application in lightweight and thin consumer electronic products. Moreover, the current transparent conductive glass and cover glass still have the disadvantages of being fragile, breakable, and non-bendable.

[0004] The current packaging method of flexible perovskite solar photovoltaic modules includes: sequentially performing electron or hole transport layer, perovskite light-absorbing layer, hole or electron transport layer, and upper electrode fabrication on a transparent conductive film (lower electrode) to fabricate a perovskite photovoltaic cell, and then using upper and lower water and oxygen barrier films to package the flexible perovskite. This flexible packaging method uses a plastic substrate to replace glass, which can solve the problems of traditional glass being fragile, breakable, and non-bendable. However, it causes the plastic film to be easily scratched, indented, and bruised, which affects the photovoltaic cell. Moreover, the thinner the overall thickness of the device, the more likely it is to cause damage to the appearance of the device or the barrier film surface when bending, which affects the photoelectric conversion efficiency. SUMMARY

[0005] Therefore, the embodiments of the present application provide a flexible perovskite photovoltaic device and a preparation method thereof to solve the technical problem that the existing photovoltaic device causes damage to the appearance of the device or the barrier film surface when bending, which affects the photoelectric conversion efficiency.

[0006] In a first aspect, the embodiments of the present application provide a flexible perovskite photovoltaic device, comprising:

[0007] a perovskite photovoltaic cell layer;

[0008] a water and oxygen barrier film layer covering at least two sides of the perovskite photovoltaic cell layer, and forming a first water and oxygen barrier film and a second water and oxygen barrier film on the two sides of the perovskite photovoltaic cell layer, respectively; and

[0009] an elastic encapsulation layer covering the water-oxygen barrier film layer, the elastic encapsulation layer forming a first encapsulation layer on a side of the first water-oxygen barrier film away from the perovskite photovoltaic cell layer, and forming a second encapsulation layer on a side of the second water-oxygen barrier film away from the perovskite photovoltaic cell layer;

[0010] wherein the Young's modulus of the above layer structure satisfies the following relationship: the perovskite photovoltaic cell layer > the water-oxygen barrier film layer > the elastic encapsulation layer;

[0011] the thickness of the first encapsulation layer > the thickness of the first water-oxygen barrier film > the thickness of the perovskite photovoltaic cell layer, and the thickness of the second encapsulation layer > the thickness of the second water-oxygen barrier film > the thickness of the perovskite photovoltaic cell layer.

[0012] In some embodiments, the Young's modulus of the elastic encapsulation layer is <0.5 Gpa, and the Shore hardness A is <60.

[0013] In some embodiments, the thickness of the first encapsulation layer is 50-5000 μm, and the thickness of the second encapsulation layer is 50-5000 μm. Preferably, the thickness of the first encapsulation layer is equal to the thickness of the second encapsulation layer.

[0014] In some embodiments, the thickness of the first water-oxygen barrier film is 10-100 μm, and the thickness of the second water-oxygen barrier film is 10-100 μm. Preferably, the thickness of the first water-oxygen barrier film is equal to the thickness of the second water-oxygen barrier film.

[0015] In some embodiments, the Young's modulus of the first water-oxygen barrier film and the second water-oxygen barrier film is 0.5-100 Gpa.

[0016] In some embodiments, the first water-oxygen barrier film comprises a first substrate and a first barrier layer disposed on the first substrate, and the first barrier layer is connected to the perovskite photovoltaic cell layer.

[0017] In some embodiments, the second water-oxygen barrier film comprises a second substrate and a second barrier layer disposed on the second substrate, and the second barrier layer is connected to the perovskite photovoltaic cell layer.

[0018] In some embodiments, the thickness of the first substrate and the second substrate is 10-100 μm.

[0019] In some embodiments, the first substrate and the second substrate are any one of PI transparent optical film, PET transparent optical film, and PC transparent optical film.

[0020] In some embodiments, the thickness of the first barrier layer and the second barrier layer is 10-300 nm.

[0021] In some embodiments, the first barrier layer and the second barrier layer are inorganic oxide thin films or organic resin and inorganic oxide composite thin films.

[0022] In some embodiments, the perovskite photovoltaic cell layer comprises a first electrode layer, an electron transport layer, a perovskite light-absorbing layer, an electron hole layer, and a second electrode layer arranged in a stack, or the perovskite photovoltaic cell layer comprises a first electrode layer, an electron hole layer, a perovskite light-absorbing layer, an electron transport layer, and a second electrode layer arranged in a stack.

[0023] In some embodiments, the flexible perovskite photovoltaic device further comprises an encapsulation adhesive layer, the encapsulation adhesive layer comprises a first adhesive layer and a second adhesive layer, the first adhesive layer is located between the second electrode layer and the second water and oxygen barrier film, the second adhesive layer is located on the peripheral side of the perovskite photovoltaic cell layer, and the second adhesive layer is connected to the first water and oxygen barrier film and the second water and oxygen barrier film.

[0024] In a second aspect, the embodiments of the present application provide a method for manufacturing a flexible perovskite photovoltaic device, comprising:

[0025] providing a first water and oxygen barrier film;

[0026] forming a first electrode layer, an electron hole layer, a perovskite light-absorbing layer, an electron transport layer, and a second electrode layer on the first water and oxygen barrier film in sequence to obtain a perovskite cell layer, or forming a first electrode layer, an electron transport layer, a perovskite light-absorbing layer, an electron hole layer, and a second electrode layer on the first water and oxygen barrier film in sequence to obtain a perovskite cell layer;

[0027] forming a second water and oxygen barrier film on a side of the second electrode layer away from the perovskite cell layer;

[0028] forming an elastic encapsulation layer on the first water and oxygen barrier film and the second water and oxygen barrier film to obtain the flexible perovskite photovoltaic device.

[0029] In some embodiments, the method further comprises, before forming the second water and oxygen barrier film on the side of the second electrode layer away from the perovskite cell layer:

[0030] forming an encapsulation adhesive layer on a side of the second electrode layer away from the perovskite light-absorbing layer, the encapsulation adhesive layer extending towards the peripheral side of the perovskite cell layer and being connected to the first water and oxygen barrier film.

[0031] In some embodiments, the method further comprises, before forming the second water and oxygen barrier film on the side of the second electrode layer away from the perovskite cell layer:

[0032] providing a first substrate;

[0033] forming a first barrier layer on the first substrate to obtain the first water and oxygen barrier film.

[0034] The flexible perovskite photovoltaic device and the preparation method thereof provided by the embodiments of the present application, by applying the "gradient stacking" design to the packaging of the flexible perovskite photovoltaic device, the flexible perovskite photovoltaic device comprises, from inside to outside, a perovskite photovoltaic cell layer, a water and oxygen barrier film layer and an elastic packaging layer, wherein the soft elastic packaging layer is used to protect the water and oxygen barrier film layer, and the high flexibility can be maintained in the case of the increase of the overall thickness, so as to realize the flexible bending. Specifically, the gradient stacking design includes two aspects, one is the gradient of thickness, that is, the elastic packaging layer > the water and oxygen barrier film layer > the perovskite photovoltaic cell layer, and the other is the gradient of Young's modulus, that is, the perovskite photovoltaic cell layer > the water and oxygen barrier film layer > the elastic packaging layer; the perfect combination of the modulus gradient and the thickness gradient makes the external stress attenuate layer by layer before reaching the perovskite photovoltaic cell layer. The thick soft outer layer absorbs most of the impact and bending strain, the water and oxygen barrier film layer with the medium thickness and rigidity further disperses the stress and protects itself, and finally only a very small stress reaches the thin and brittle perovskite photovoltaic cell layer. This makes the device be able to withstand thousands of bending cycles without significant damage, and meet the requirements of flexible / wearable applications. The water and oxygen barrier film layer with high barrier performance is placed in the position close to the perovskite photovoltaic cell layer and is protected by the external elastic packaging layer. The elastic packaging layer protects the water and oxygen barrier film layer from mechanical damage (breakage, scratching) and maintains the barrier integrity. At the same time, the elastic packaging layer itself also provides a certain auxiliary barrier effect. The elastic packaging layer with the thickest thickness and the lowest modulus dominates the flexibility of the device, so that it can be easily rolled or attached to a curved surface. Although the internal water and oxygen barrier film layer and the perovskite photovoltaic cell layer are relatively rigid, the negative impact on the overall flexibility is minimized due to the thin thickness and the wrapping of the soft material, so that the flexible perovskite photovoltaic device of the present application will not cause appearance damage to the device or the surface of the water and oxygen barrier film when used in bending, and ensures the photoelectric conversion efficiency and improves the service life of the device. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creating any creative labor.

[0036] Figure 1 is a structure diagram of the flexible perovskite photovoltaic device provided by the embodiments of the present application Figure One ;

[0037] Figure 2 is a structure diagram of the flexible perovskite photovoltaic device provided by the embodiments of the present application Figure Two ;

[0038] Figure 3 is a structural schematic of a flexible perovskite photovoltaic device provided by an embodiment of the present application Figure Three ;

[0039] Figure 4 is a structural schematic of a flexible perovskite photovoltaic device provided by an embodiment of the present application Figure Four ;

[0040] Figure 5 is a structural schematic of a water-oxygen barrier film layer in a flexible perovskite photovoltaic device provided by an embodiment of the present application

[0041] Figure 6 is a structural schematic of a first water-oxygen barrier film and a first electrode layer in a flexible perovskite photovoltaic device provided by an embodiment of the present application Figure One ;

[0042] Figure 7 is a structural schematic of a first water-oxygen barrier film and a first electrode layer in a flexible perovskite photovoltaic device provided by an embodiment of the present application Figure Two ;

[0043] Figure 8 is a structural schematic of a first water-oxygen barrier film and a first electrode layer in a flexible perovskite photovoltaic device provided by an embodiment of the present application Figure Three ;

[0044] Figure 9 is a structural schematic of a flexible perovskite photovoltaic device provided by an embodiment of the present application Figure Five ;

[0045] Figure 10 is a process structural schematic of a preparation method of a flexible perovskite photovoltaic device provided by an embodiment of the present application Figure One ;

[0046] Figure 11 is a process structural schematic of a preparation method of a flexible perovskite photovoltaic device provided by an embodiment of the present application Figure Two ;

[0047] Figure 12 is a structural schematic of a flexible perovskite photovoltaic device prepared by a preparation method of a flexible perovskite photovoltaic device provided by an embodiment of the present application.

[0048] wherein, the reference signs:

[0049] 10, perovskite photovoltaic cell layer; 11, first electrode layer; 12, electron transport layer; 13, perovskite light absorption layer; 14, electron hole layer; 15, second electrode layer;

[0050] 20, water-oxygen barrier film layer; 21, first water-oxygen barrier film; 211, first base material; 212, first barrier layer; 22, second water-oxygen barrier film; 221, second base material; 222, second barrier layer;

[0051] 30, elastic encapsulation layer; 31, first encapsulation layer; 32, second encapsulation layer;

[0052] 40, encapsulation adhesive layer; 41, first adhesive layer; 42, second adhesive layer. DETAILED DESCRIPTION

[0053] In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular sequences of acts, techniques, etc., in order to provide a thorough understanding of the embodiments of the present application. However, it will be apparent to those skilled in the art that the present application can be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known methods, devices, and circuits are omitted so as not to obscure the description of the present application with unnecessary detail.

[0054] It should also be understood that the term “and / or” as used herein, refers to any one or more of the associated listed items, and all possible combinations of the associated listed items.

[0055] It should be noted that when an element is referred to as being “fixed” or “set” on another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being “connected” to another element, it can be directly connected to the other element or indirectly connected to the other element.

[0056] It should be understood that the terms “length”, “width”, “upper”, “lower”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inner”, “outer” and the like, indicate relative or positional relationships based on the orientation or position shown in the drawings, and are merely used to facilitate the description of the embodiments of the present application and simplify the description, and therefore cannot be understood as indicating or implying that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the embodiments of the present application.

[0057] In addition, in the description of the embodiments of the present application and the appended claims, the terms “first”, “second”, “third” and the like are merely used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0058] Reference to "some embodiments," "certain embodiments," "certain implementations," "some implementations," "some of the embodiments," or the like, in the present embodiments description indicates that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least some embodiments. The appearances of the phrases "in some embodiments," "in certain embodiments," "in other embodiments," "in yet other embodiments," or the like, in various places in the specification are not necessarily all referring to the same embodiments, although the phrases can be. Furthermore, the terms "comprises," "comprising," "includes," "including," "has," "having," and the like, are intended to be open-ended terms that do not exclude additional, unrecited elements or methods. The term "multiple" means two or more.

[0059] The current packaging method of flexible perovskite solar photovoltaic modules is as follows: a perovskite photovoltaic cell is made on a transparent conductive film in sequence by an electron or hole transport layer, a perovskite light absorption layer, a hole or electron transport layer, and an upper electrode, and then a flexible perovskite is packaged by using a water and oxygen barrier film. This flexible packaging method uses a plastic substrate to replace glass, which can solve the problems of fragility, breakage, and non-bendability of traditional products, but it causes the plastic film material to be easily scratched, indented, and bruised, thereby affecting the photovoltaic cell. The thinner the overall thickness, the more likely it is to cause damage to the appearance of the photovoltaic device or the barrier film surface when bending, thereby affecting the photoelectric conversion efficiency; if the thickness of the water and oxygen barrier film is increased or a hardening layer is added for protection, the flexibility of the flexible bending characteristics will be affected; the thicker the module thickness of the perovskite, the more difficult it is to achieve flexible bending; the harder the surface hardness of the plastic film material, the more difficult it is to achieve flexible bending.

[0060] Based on this, the present embodiments propose a new flexible perovskite photovoltaic packaging design, which uses "gradient stacking" to package the flexible perovskite photovoltaic device; the present embodiments use a soft elastic packaging layer to protect the water and oxygen barrier film layer, and can still maintain high flexibility under the design of increasing the overall thickness.

[0061] The first aspect of the present embodiments provides a flexible perovskite photovoltaic device, as shown in Figure 1 and Figure 2 which includes a perovskite photovoltaic cell layer 10, a water and oxygen barrier film layer 20, and an elastic packaging layer 30.

[0062] The water and oxygen barrier film layer 20 covers at least two sides of the perovskite photovoltaic cell layer 10, and forms a first water and oxygen barrier film 21 and a second water and oxygen barrier film 22 on the two sides of the perovskite photovoltaic cell layer 10, respectively.

[0063] The elastic encapsulation layer 30 covers the water-oxygen barrier film layer 20, and the elastic encapsulation layer 30 forms a first encapsulation layer 31 on a side of the first water-oxygen barrier film 21 away from the perovskite photovoltaic cell layer 10, and forms a second encapsulation layer 32 on a side of the second water-oxygen barrier film 22 away from the perovskite photovoltaic cell layer 10;

[0064] The Young's modulus of the perovskite photovoltaic cell layer 10, the water-oxygen barrier film layer 20, and the elastic encapsulation layer 30 satisfies the following relationship: perovskite photovoltaic cell layer 10 > water-oxygen barrier film layer 20 > elastic encapsulation layer 30;

[0065] The thickness of the first encapsulation layer 31 > the thickness of the first water-oxygen barrier film 21 > the thickness of the perovskite photovoltaic cell layer 10, and the thickness of the second encapsulation layer 32 > the thickness of the second water-oxygen barrier film 22 > the thickness of the perovskite photovoltaic cell layer 10.

[0066] The flexible perovskite photovoltaic device provided by the embodiments of the present application applies a "gradient stacking" design to the encapsulation of the flexible perovskite photovoltaic device. The flexible perovskite photovoltaic device comprises, from inside to outside, a perovskite photovoltaic cell layer 10, a water-oxygen barrier film layer 20, and an elastic encapsulation layer 30. The soft elastic encapsulation layer 30 is used to protect the water-oxygen barrier film layer 20, and the flexible perovskite photovoltaic device still maintains high flexibility while increasing the overall thickness, so as to realize flexible bending. Specifically, the gradient stacking design includes two aspects. One is the gradient in thickness, that is, elastic encapsulation layer 30 > water-oxygen barrier film layer 20 > perovskite photovoltaic cell layer 10. The other is the gradient in Young's modulus, that is, perovskite photovoltaic cell layer 10 > water-oxygen barrier film layer 20 > elastic encapsulation layer 30. The perfect combination of the modulus gradient and the thickness gradient makes the external stress attenuate layer by layer before reaching the perovskite photovoltaic cell layer 10. The thick soft outer layer absorbs most of the impact and bending strain, the water-oxygen barrier film layer 20 with medium thickness and rigidity further disperses the stress and protects itself, and finally only a very small stress reaches the thin and brittle perovskite photovoltaic cell layer 10. This makes the device able to withstand thousands of bending cycles without significant damage, meeting the needs of flexible / wearable applications. The water-oxygen barrier film layer 20 with high barrier performance is placed in close proximity to the perovskite photovoltaic cell layer 10 and is protected by the external elastic encapsulation layer 30. The elastic encapsulation layer 30 protects the water-oxygen barrier film layer 20 from mechanical damage (breakage, scratching) and maintains its barrier integrity. At the same time, the elastic encapsulation layer 30 itself also provides certain auxiliary barrier effect. The thickest and lowest modulus elastic encapsulation layer 30 dominates the flexibility of the device, making it easy to roll or conform to curved surfaces. Although the internal water-oxygen barrier film layer 20 and the perovskite photovoltaic cell layer 10 are relatively rigid, the negative impact on overall flexibility is minimized due to their thin thickness and being wrapped in soft material, so that the flexible perovskite photovoltaic device of the present application does not cause appearance damage to the device or the surface of the water-oxygen barrier film when bent in use, ensures the photoelectric conversion efficiency, and improves the service life of the device.

[0067] It should be noted that, as shown in Figure 1 and Figure 2 The water and oxygen barrier film layer 20 covers at least two sides of the perovskite photovoltaic cell layer 10. The two sides of the perovskite photovoltaic cell layer 10 refer to the two sides in the thickness direction of the device (i.e. the stacking direction of the perovskite photovoltaic cell layer 10), and the water and oxygen barrier film layer 20 covering at least two sides of the perovskite photovoltaic cell layer 10 includes the following cases: one is that the water and oxygen barrier film layer 20 is arranged on the two sides of the perovskite photovoltaic cell layer 10 to form the first water and oxygen barrier film 21 and the second water and oxygen barrier film 22; two is that the water and oxygen barrier film layer 20 completely covers the perovskite photovoltaic cell layer 10, not only forming the first water and oxygen barrier film 21 and the second water and oxygen barrier film 22 on the two sides of the perovskite photovoltaic cell layer 10, but also covering the periphery of the perovskite photovoltaic cell layer 10; three is that the water and oxygen barrier film layer 20 forms the first water and oxygen barrier film 21 and the second water and oxygen barrier film 22 on the two sides of the perovskite photovoltaic cell layer 10, and also covers at least one side of the perovskite photovoltaic cell layer 10.

[0068] In application, the main role of the water and oxygen barrier film layer 20 is to effectively block the penetration of external water and oxygen through the substrate to the internal structure of the perovskite photovoltaic device (especially the perovskite material, i.e. the light absorbing layer in the functional layer), thereby effectively avoiding the decomposition of the perovskite material, and improving the service life of the entire perovskite photovoltaic device.

[0069] In application, the thickness of the first encapsulation layer 31 is 50-5000 μm, and the thickness of the second encapsulation layer 32 is 50-5000 μm. In a preferred embodiment, the thickness of the first encapsulation layer 31 is equal to the thickness of the second encapsulation layer 32. The thickness of the first water and oxygen barrier film 21 is 10-100 μm, and the thickness of the second water and oxygen barrier film 22 is 10-100 μm. In a preferred embodiment, the thickness of the first water and oxygen barrier film 21 is equal to the thickness of the second water and oxygen barrier film 22; the Young's modulus of the first water and oxygen barrier film 21 and the second water and oxygen barrier film 22 is 0.5-100 Gpa. The differences and corresponding effects under the gradient stacking design are as follows:

[0070] Thickness difference: elastic encapsulation layer 30 (50-5000 pm) > water-oxygen barrier film layer 20 (10-100 pm) > perovskite photovoltaic cell layer 10 (0.5-10 pm); sufficient thickness (typically in microns) is needed to ensure its density and pinhole-free to achieve effective water-oxygen barrier. Sufficient thickness is needed to provide effective stress buffer space, physical protection, and as the last environmental barrier. The innermost layer (the thinnest perovskite photovoltaic cell layer 10) meets the optoelectronic functional requirements, minimizing its own mechanical vulnerability due to thickness. The middle layer (the water-oxygen barrier film layer 20 of moderate thickness) provides sufficient but not redundant thickness to ensure high barrier performance while avoiding excessive sacrifice of flexibility. Its thickness is greater than that of the perovskite layer to provide effective coverage and protection. The outermost layer (the thickest elastic encapsulation layer 30) has sufficient thickness to accommodate greater deformation and more effectively absorb and dissipate mechanical energy, significantly improving protection. It provides additional protection against physical damage such as scratches, wear, impact, etc. Although its water-oxygen barrier property may not be as good as that of a dedicated barrier film, the increase in thickness also lengthens the water-oxygen penetration path, providing additional environmental protection time. As the thickest and softest layer, it determines the curvature radius and flexibility of the device as a whole when bent. The thick soft layer makes the device easier to bend without generating excessive internal stress. It achieves an optimized allocation of thickness for function and protection. The perovskite layer is thin and functionalized, the barrier layer is moderately thick to ensure core protection functions, and the elastic encapsulation layer 30 maximizes its stress buffering and physical protection. This thickness gradient and modulus gradient work together to achieve excellent flexibility, bending fatigue resistance, and physical protection capability.

[0071] Young's modulus: perovskite photovoltaic cell layer 10 (>100 Gpa) > water-oxygen barrier film layer 20 (0.5-100 Gpa) > elastic encapsulation layer 30 (<0.5 Gpa). The core objective is to avoid direct transmission of externally applied bending, stretching or impact stress to the fragile perovskite active layer. The innermost layer (perovskite photovoltaic cell layer 10 with high modulus) itself needs certain structural integrity to support the photoelectric conversion function. High modulus makes it less prone to large deformation itself. The middle layer (water-oxygen barrier film layer 20 with medium modulus), the barrier film is usually composed of relatively rigid inorganic materials or dense polymers, which has certain brittleness itself. Its modulus is higher than the outermost layer but lower than the perovskite layer, which plays two roles: primary stress dispersion, receiving part of the stress from the external elastic layer and dispersing it partially; providing physical support for the perovskite layer and serving as the main water-oxygen barrier, which itself needs certain rigidity to maintain its density and barrier performance. The outermost layer (elastic encapsulation layer 30 with low modulus), when the device is subjected to bending, pressing or impact, the low-modulus, high-elasticity encapsulation layer first undergoes large, recoverable deformation, absorbing and dissipating most of the external mechanical energy, greatly preventing the transmission of external stress to the more rigid barrier layer and the brittle perovskite layer. Prevent the water-oxygen barrier film layer 20 from breaking down due to direct bearing of external force. The external stress is greatly attenuated when passing through the elastic encapsulation layer 30, and the stress transmitted to the water-oxygen barrier film layer 20 has been reduced; after being partially dispersed / attenuated by the water-oxygen barrier film layer 20 (whose modulus is still higher than that of the elastic encapsulation layer 30), the stress finally reaching the perovskite photovoltaic cell layer 10 becomes very small, greatly reducing the risk of cracking, delamination or failure of the perovskite layer. This significantly improves the mechanical durability of the device under repeated bending, curling or slight impact.

[0072] In some embodiments, the Young's modulus of the elastic encapsulation layer 30 is <0.5 Gpa, and the Shore hardness A is <60. Low Young's modulus (soft elasticity), the material of the elastic encapsulation layer 30 is prone to large deformation when stressed, can efficiently absorb external bending, impact or vibration energy, greatly reducing the mechanical stress transmitted to the internal perovskite photovoltaic cell layer 10. When the photovoltaic device with elastic encapsulation layer 30 is repeatedly bent or stretched, the elastic encapsulation layer 30 dissipates energy through viscoelastic energy dissipation mechanism, protecting the brittle perovskite layer from fatigue damage. In applications, the material of the elastic encapsulation layer 30 can be a soft elastic material such as polydimethylsiloxane, silicone, rubber, silicone rubber, acrylic glue, etc.

[0073] In applications, such as Figure 4As shown, the perovskite photovoltaic cell layer 10 includes a first electrode layer 11, an electron transport layer 12, a perovskite light-absorbing layer 13, an electron hole layer 14, and a second electrode layer 15 arranged in a stack, or the perovskite photovoltaic cell layer 10 includes a first electrode layer 11, an electron hole layer 14, a perovskite light-absorbing layer 13, an electron transport layer 12, and a second electrode layer 15 arranged in a stack. The conventional structure (first electrode layer 11 / electron transport layer 12 / perovskite layer / hole transport layer / second electrode layer 15) follows the traditional electron-hole flow design. The electron transport layer 12 (ETL) is immediately below the perovskite light-absorbing layer 13, which can quickly extract photo-generated electrons and inject them into the first electrode layer 11 (cathode), reducing the recombination of electrons at the perovskite interface; the hole transport layer (HTL) is above the perovskite light-absorbing layer 13, which efficiently transports holes to the second electrode (anode). The advantages are: the electron transport path is short and direct, especially suitable for high electron mobility materials, which can significantly improve the electron collection efficiency; at the same time, the hole transport layer at the top layer can be compatible with polymer materials with better stability, reducing the risk of environmental erosion. The overall structure is mature in process, suitable for rigid or flexible substrates, and the optimization space for photoelectric conversion efficiency is clear. The inverted structure (first electrode layer 11 / hole transport layer / perovskite layer / electron transport layer 12 / second electrode layer 15) reverses the carrier transport direction: the hole transport layer (HTL) directly contacts the first electrode (anode) and preferentially extracts holes; the electron transport layer 12 (ETL) is above the perovskite, guiding electrons to the second electrode (cathode). The core advantage is that the hole transport layer is placed at the bottom and can be selected from high-stability inorganic materials or low-defect organic materials, effectively suppressing interface degradation; the electron transport layer 12 at the top can avoid the high-temperature sintering step in the traditional structure, compatible with low-temperature flexible processes. In addition, the inverted structure reduces the direct contact between the perovskite and the metal electrode, reducing the risk of ion migration, and is more suitable for stack cell integration and long-term reliability requirements.

[0074] In some embodiments, as Figure 3 and Figure 4As shown, the flexible perovskite photovoltaic device also includes an encapsulating adhesive layer 40, which includes a first adhesive layer 41 and a second adhesive layer 42. The first adhesive layer 41 is located between the second electrode layer 15 and the second water-oxygen barrier film 22, and the second adhesive layer 42 is located on the periphery of the perovskite photovoltaic cell layer 10. The second adhesive layer 42 is connected to the first water-oxygen barrier film 21 and the second water-oxygen barrier film 22. The first adhesive layer 41 is used to bond and encapsulate the second water-oxygen barrier film 22 to the second electrode layer 15 of the perovskite photovoltaic cell layer 10. The perovskite photovoltaic cell layer 10 is located between the first water-oxygen barrier film 21 and the second water-oxygen barrier film 22, with the second adhesive layer 42 on its side. The second adhesive layer 42 serves to connect the first water-oxygen barrier film 21 and the second water-oxygen barrier film 22. Furthermore, the sides of the second adhesive layer 42, the first water and oxygen barrier film 21, and the second water and oxygen barrier film 22 are covered by the elastic encapsulation layer 30 to protect the entire perovskite photovoltaic cell layer 10, prevent the interior from being corroded by external moisture, and improve its service life.

[0075] In some embodiments, such as Figure 5 As shown, the first water and oxygen barrier film 21 includes a first substrate 211 and a first barrier layer 212 disposed on the first substrate 211, the first barrier layer 212 being connected to the perovskite photovoltaic cell layer 10; the second water and oxygen barrier film 22 includes a second substrate and a second barrier layer disposed on the second substrate, the second barrier layer being connected to the perovskite photovoltaic cell layer 10. Thus, a layer structure of the perovskite photovoltaic cell layer 10 can be sequentially fabricated on the first substrate 211.

[0076] In applications, the water and oxygen barrier film consists of a plastic substrate and a barrier layer. The thickness of the plastic substrate can be 10–100 μm, and the material can be a transparent optical film such as polyimide (PI), polyethylene terephthalate (PET), or polycarbonate (PC). The barrier layer can be a single layer or multiple layers of stacked inorganic materials, such as silicon oxide, silicon nitride, aluminum oxide, or a multilayer stack of organic and inorganic materials. Alternatively, the water and oxygen barrier layer material can also be an inorganic oxide film, such as silicon oxide, aluminum oxide, silicon nitride, or zinc oxide, with a thickness between 10 and 300 nm. The barrier layer material can also be a composite film of organic and inorganic oxides, such as a two-layer film (alumina / organic resin / alumina) or a multilayer film (silicon nitride / organic resin / silicon nitride / organic resin / silicon oxide), where the inorganic oxide thickness is less than 300 nm. Specifically, the thickness of the first or second barrier layer 212 is 10 nm–300 nm. In applications, the thickness of the barrier layer can be any value within the range of 10nm to 300nm, such as 10nm, 20nm, 50nm, 100nm, 120nm, 150nm, 200nm, 250nm, or 300nm. When the barrier layer is less than 10nm, inorganic oxide films are prone to pinhole defects due to process fluctuations, leading to localized failures; while a thickness of 10-50nm ensures density while maintaining low material usage. For organic-inorganic composite barrier layers or multilayer stacked structures (such as "sandwich" structures), appropriately increasing the thickness (e.g., 200nm) can compensate for single-layer microcracks through redundant design, improving overall barrier reliability. In a specific embodiment, a multilayer structure of alternating SiO2 and polyimide deposition is used, with each layer being 50-100nm and the total thickness being 200-300nm, resulting in a barrier performance improvement of more than 10 times. In the 100–300 nm range, organic layers (such as polyurethane) can act as stress buffer layers to absorb strain during bending, while inorganic layers provide barrier functions. The combination of the two achieves a balance between rigidity and flexibility.

[0077] In application, the positional relationship between the first water-oxygen barrier membrane 21 and the first electrode layer 11 can be as follows: Figure 6 As shown, the first electrode layer 11 is shorter than the first water-oxygen barrier film 21, leaving gaps at both ends of the first electrode layer 11 to allow for sealing by the subsequent encapsulating adhesive layer 40 or sealing by the second water-oxygen barrier film 22. In other embodiments, the positional relationship between the first water-oxygen barrier film 21 and the first electrode layer 11 can be as follows: Figure 7 As shown, the first electrode layer 11 and the first water-oxygen barrier membrane 21 have the same length, and the first electrode layer 11 is located on the first water-oxygen barrier membrane 21. In other embodiments, the positional relationship between the first water-oxygen barrier membrane 21 and the first electrode layer 11 can be as follows: Figure 8 As shown, the first electrode layer 11 is embedded in the first water and oxygen barrier film 21, which can effectively protect the first electrode layer 11 and also prevent water and oxygen from entering.

[0078] In the application, as shown in Figure 9 The second adhesive layer 42 is located at the side of the perovskite photovoltaic cell layer 10, and the second adhesive layer 42 is connected with the first water-oxygen barrier film 21 and the second water-oxygen barrier film 22. The first water-oxygen barrier film 21 and the second water-oxygen barrier film 22 are connected, and the elastic encapsulation layer 30 is connected with the first water-oxygen barrier film 21 and the second water-oxygen barrier film 22, but is not connected with the second adhesive layer 42. In this way, the first water-oxygen barrier film 21 and the second water-oxygen barrier film 22 completely cover and protect the perovskite photovoltaic cell layer 10.

[0079] The embodiment of the present application also provides a preparation method of a flexible perovskite photovoltaic device, comprising:

[0080] S10, providing a first water-oxygen barrier film 21;

[0081] S20, sequentially forming a first electrode layer 11, an electron-hole layer 14, a perovskite light-absorbing layer 13, an electron transport layer 12 and a second electrode layer 15 on the first water-oxygen barrier film 21 to obtain a perovskite cell layer, or sequentially forming a first electrode layer 11, an electron transport layer 12, a perovskite light-absorbing layer 13, an electron-hole layer 14 and a second electrode layer 15 on the first water-oxygen barrier film 21 to obtain a perovskite cell layer;

[0082] S30, forming a second water-oxygen barrier film 22 on a side of the second electrode layer 15 away from the perovskite cell layer;

[0083] S40, forming an elastic encapsulation layer 30 on the first water-oxygen barrier film 21 and the second water-oxygen barrier film 22 to obtain a flexible perovskite photovoltaic device.

[0084] The preparation method of the flexible perovskite photovoltaic device provided by the embodiment of the present application takes the first water-oxygen barrier film 21 as a growth substrate, provides initial environmental isolation in the whole process of cell layer manufacturing, and prevents water-oxygen erosion during perovskite processing. The water-oxygen barrier films are directly deposited on both sides of the cell layer (S10 / S30), a dense sandwich structure is formed, and the environmental stability is maximized. The electrodes / functional layers can be processed at low temperature by solution processing (such as slot coating) on the flexible barrier film, avoiding high-temperature damage and being compatible with roll-to-roll mass production. The elastic encapsulation is integrated, the elastic layer (S40) finally wrapped covers the double barrier films, realizing the synergistic protection of mechanical stress buffering and environmental sealing, and avoiding the risk of delamination. The method optimizes the layer sequence of “barrier-power generation-barrier-buffering” and simultaneously solves the environmental sensitivity and mechanical fragility pain points of the flexible device in a single process, significantly improving the mass production feasibility and product reliability.

[0085] In the S10 step, in some embodiments, the first water-oxygen barrier film 21 is provided by:

[0086] The first substrate 211 is provided;

[0087] A first barrier layer 212 is formed on a first substrate 211 to obtain a first water and oxygen barrier film 21. The first substrate 211 uses a flexible substrate (such as PET / polyimide) as a mechanical carrier, giving the barrier film anti-bending properties; an inorganic barrier layer (such as Al2O3, SiN) is directly grown on the substrate. x To prevent high-temperature damage and maintain film flexibility, the first barrier layer 212 is prepared before battery manufacturing, isolating water and oxygen permeation from the process source and protecting the perovskite layer from degradation during subsequent deposition. Independent control of the substrate and barrier layer can achieve an ultra-low defect interface, improving overall water and oxygen barrier performance. This design makes rigid encapsulation materials flexible, building a stable and reliable protective starting point at the front end of the process, providing a "shield" of protection for environmentally sensitive materials throughout the entire process.

[0088] In applications, water- and oxygen-barrier materials (SiN2) are deposited on 50μm plastic substrates using magnetron sputtering or chemical vapor deposition. x SiO x A first water and oxygen barrier film 21 is obtained by depositing a film (with a total thickness of less than 3 μm) onto the surface of a substrate.

[0089] After step S20 and before step S30, in some embodiments, before the second water-oxygen barrier film 22 is formed on the side of the second electrode layer 15 away from the perovskite cell layer, the following is included:

[0090] An encapsulating adhesive layer 40 is formed on the side of the second electrode layer 15 away from the perovskite light-absorbing layer 13. The encapsulating adhesive layer 40 extends towards the periphery of the perovskite battery layer and is connected to the first water and oxygen barrier film 21. The encapsulating adhesive layer 40 extends laterally from the surface of the second electrode to the edge of the first barrier film, directly wrapping the sidewall of the battery layer, completely blocking the lateral permeation path of water and oxygen, and solving the pain point of the "edge effect" in traditional encapsulation. The encapsulating adhesive layer 40 forms a double seal of chemical bonding and physical filling with the first and second barrier films, eliminating interlayer micro-gaps. The adhesive layer is pre-placed before the deposition of the second barrier film to avoid bending micro-cracks caused by direct contact between the rigid film and the electrode, while providing an elastic transition substrate for subsequent lamination. The liquid adhesive spin coating / spray coating can precisely control the extension width and is compatible with the encapsulation requirements of irregularly shaped devices.

[0091] This design upgrades the "point-to-surface" seal to a "three-dimensional full-coverage" seal through topology optimization of the adhesive layer space, effectively improving device lifespan and achieving synergistic mechanical protection and environmental barrier in a single step.

[0092] In applications, such as Figures 10 to 12 As shown, the specific process flow for fabricating flexible perovskite photovoltaic devices is as follows:

[0093] S10. On a 50μm first substrate 211, water- and oxygen-barrier material (SiN) is deposited using magnetron sputtering or chemical vapor deposition.x SiO x A first water-oxygen barrier film 21 is formed on the surface of the first substrate 211 by sputtering a transparent conductive material on the first barrier layer 212 using a magnetron sputtering device, and a second water-oxygen barrier film 22 is formed on the surface of the second substrate 212 by sputtering a transparent conductive material on the second barrier layer 213 using a magnetron sputtering device.

[0094] S20, a first laser etching is performed to pattern the transparent conductive layer into a sub-cell pattern, a slot coating device is used to coat the hole transport layer material, and then a heating platform is used to dry the coated material at 120°C for 5 minutes. Subsequently, the perovskite light-absorbing layer 13 is coated using a slot coating device, and then a heating platform is used to dry the coated material at 150°C for 10 minutes. A vacuum evaporation process is used to evaporate the electron transport layer 12 (C 60 BCP (bathocuproin) onto the perovskite light-absorbing layer 13, and a second laser etching is performed to pattern the hole transport layer and the electron transport layer 12 and the perovskite light-absorbing layer 13. A magnetron sputtering device is used to sputter the second electrode layer 15, and a third laser etching is performed to connect the layers in series.

[0095] S30, the upper water-oxygen barrier film and the perovskite photovoltaic cell layer 10 are bonded and encapsulated using an encapsulating adhesive material, the perovskite photovoltaic cell layer 10 is located between the first water-oxygen barrier film 21 and the second water-oxygen barrier film 22, and the side portions are encapsulating adhesive layers 40.

[0096] S40, the flexible encapsulating material is used to cover the water-oxygen encapsulating layer by means of blade coating and is cured at 80°C for 10 minutes to obtain a flexible perovskite photovoltaic device.

[0097] In the above embodiments, the description of each embodiment focuses on different aspects, and the parts not described or recorded in a certain embodiment can be referred to the related description of other embodiments.

[0098] The above-described embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the foregoing embodiments of the present application have been described in detail, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements for some technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the embodiments of the present application.

Claims

1. A flexible perovskite photovoltaic device, characterized in that, The flexible perovskite photovoltaic device comprises: a perovskite photovoltaic cell layer; a water-oxygen barrier film layer covering at least two sides of the perovskite photovoltaic cell layer, forming a first water-oxygen barrier film and a second water-oxygen barrier film on the two sides of the perovskite photovoltaic cell layer, respectively; and an elastic encapsulation layer covering the water-oxygen barrier film layer, the elastic encapsulation layer forming a first encapsulation layer on the side of the first water-oxygen barrier film away from the perovskite photovoltaic cell layer, and forming a second encapsulation layer on the side of the second water-oxygen barrier film away from the perovskite photovoltaic cell layer; wherein the Young's modulus of the above layer structure satisfies the following relationship: the perovskite photovoltaic cell layer > the water-oxygen barrier film layer > the elastic encapsulation layer; the thickness of the first encapsulation layer > the thickness of the first water-oxygen barrier film > the thickness of the perovskite photovoltaic cell layer, and the thickness of the second encapsulation layer > the thickness of the second water-oxygen barrier film > the thickness of the perovskite photovoltaic cell layer.

2. The flexible perovskite photovoltaic device of claim 1, wherein, The Young's modulus of the elastic encapsulation layer is less than 0.5 Gpa, and the Shore A hardness is less than 60.

3. The flexible perovskite photovoltaic device of claim 1, wherein, The thickness of the first encapsulation layer is 50-5000 μm, and the thickness of the second encapsulation layer is 50-5000 μm.

4. The flexible perovskite photovoltaic device of claim 1, wherein, The thickness of the first water-oxygen barrier film is 10-100 μm, and the thickness of the second water-oxygen barrier film is 10-100 μm. The Young's modulus of the first water-oxygen barrier film and the second water-oxygen barrier film is 0.5-100 Gpa.

5. The flexible perovskite photovoltaic device of claim 1, wherein, The first water-oxygen barrier film comprises a first substrate and a first barrier layer provided on the first substrate, and the first barrier layer is connected to the perovskite photovoltaic cell layer. The second water-oxygen barrier film comprises a second substrate and a second barrier layer provided on the second substrate, and the second barrier layer is connected to the perovskite photovoltaic cell layer.

6. The flexible perovskite photovoltaic device of claim 5, wherein, The thickness of the first substrate and the second substrate is 10-100 μm. The first substrate and the second substrate are any one of a polyimide transparent optical film, a polyethylene terephthalate transparent optical film, and a polycarbonate transparent optical film. The thickness of the first barrier layer and the second barrier layer is 10-300 nm. The first barrier layer and the second barrier layer are an inorganic oxide thin film or a composite thin film of an organic resin and an inorganic oxide.

7. The flexible perovskite photovoltaic device according to any one of claims 1 to 6, wherein the perovskite layer is a CH3NH3PbI3layer. The perovskite photovoltaic cell layer comprises a first electrode layer, an electron transport layer, a perovskite light-absorbing layer, an electron hole layer, and a second electrode layer arranged in a stack, or the perovskite photovoltaic cell layer comprises a first electrode layer, an electron hole layer, a perovskite light-absorbing layer, an electron transport layer, and a second electrode layer arranged in a stack.

8. The flexible perovskite photovoltaic device of claim 7, wherein, The flexible perovskite photovoltaic device further comprises an encapsulation adhesive layer, the encapsulation adhesive layer comprising a first adhesive layer and a second adhesive layer, the first adhesive layer being located between the second electrode layer and the second water-oxygen barrier film, and the second adhesive layer being located on the peripheral side of the perovskite photovoltaic cell layer and connected to the first water-oxygen barrier film and the second water-oxygen barrier film.

9. A method of preparing a flexible perovskite photovoltaic device, characterized by, The flexible perovskite photovoltaic device comprises: a first water-oxygen barrier film is provided; forming a first electrode layer, an electron hole layer, a perovskite light-absorbing layer, an electron transport layer and a second electrode layer on the first water-oxygen barrier film to obtain a perovskite battery layer, or forming a first electrode layer, an electron transport layer, a perovskite light-absorbing layer, an electron hole layer and a second electrode layer on the first water-oxygen barrier film to obtain a perovskite battery layer; forming a second water-oxygen barrier film on a side of the second electrode layer away from the perovskite battery layer; forming an elastic encapsulation layer on the first water-oxygen barrier film and the second water-oxygen barrier film to obtain the flexible perovskite photovoltaic device.

10. The production method according to claim 9, wherein The method further comprises, before forming the second water-oxygen barrier film on the side of the second electrode layer away from the perovskite battery layer: forming an encapsulation adhesive layer on a side of the second electrode layer away from the perovskite light-absorbing layer, the encapsulation adhesive layer extending towards a peripheral side of the perovskite battery layer and being connected to the first water-oxygen barrier film; and / or, the method of providing the first water-oxygen barrier film comprises: providing a first substrate; forming a first barrier layer on the first substrate to obtain the first water-oxygen barrier film.

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