Perovskite solar cell

Abstract

According to the perovskite solar cell, a concave-convex structure is designed on a transparent electrode of the perovskite solar cell, the proportion of large-incidence-angle light entering a perovskite layer is increased, the photoelectric conversion efficiency is further improved, the capture area of the light is increased, the transmission path of the light is optimized, and the large-incidence-angle light is more effectively utilized. The reflection loss of light rays at an interface is reduced by regulating and controlling the refractive index of each functional layer. The utility model also relates to a method for preparing the high-efficiency perovskite solar cell, which comprises the steps of forming the concave-convex structure on the transparent conductive layer, forming the textured structure surface on the transparent insulating layer, coating the hole transport layer and the like, so that the accuracy and the stability of the solar cell structure are ensured. Through the design of the concave-convex structure and the optimized regulation and control of the refractive index of each layer, the efficient utilization of the perovskite solar cell on the large-incidence-angle light is realized, and the photoelectric conversion efficiency of the perovskite solar cell is obviously improved.

Description

[Technical field]

[0001] The present application belongs to the technical field of solar cells, and in particular, relates to a perovskite solar cell and a method for manufacturing the same. [Background technology]

[0002] Perovskite cells use perovskite materials as the photoelectric conversion layer to efficiently convert sunlight into electrical energy. The basic structure of a perovskite cell includes a transparent electrode, an electron transport layer, a perovskite light-absorbing layer, a hole transport layer, and a metal electrode. The transparent electrode, as the window layer of the cell, allows sunlight to pass through and shine on the perovskite light-absorbing layer. It needs to have high conductivity and good light transmittance, especially high transmittance, high work function, and high conductivity in the visible spectrum.

[0003] In the actual use of solar cells, there will be many different angles of light incident. Increasing the transmittance of incident light with a certain incident angle can make full use of light and improve the photoelectric conversion efficiency of solar cells. [Utility Model Content]

[0004] The purpose of the present application is to provide a perovskite solar cell, which can utilize light with a large incident angle through structural design, thereby improving the photoelectric conversion efficiency of the perovskite solar cell. The purpose of the present application is achieved through the following technical solution, the perovskite solar cell includes a transparent electrode, a hole transport layer, a perovskite layer, an electron transport layer, and a metal electrode layer formed in sequence on the transparent electrode, and the side of the transparent electrode where the hole transport layer is formed is a concave-convex structure;

[0005] Light is incident from the transparent electrode into the perovskite solar cell, the concave-convex structure includes a repeated distribution unit shape, and the material of the hole transport layer fills the grooves of the concave-convex structure and covers all surfaces of the concave-convex structure.

[0006] In one embodiment, the refractive index of the transparent electrode is smaller than the refractive index of the hole transport layer.

[0007] In one of the embodiments, the bottom surface of the groove and the top surface of the convex part in the concave-convex structure are velvet structure surfaces capable of trapping light, and the side edges of the convex part are planes.

[0008] In one of the embodiments, the distance between the interface between the hole transport layer and the perovskite layer and the bottom of the top surface of the convex portion is greater than 30% of the depth of the concavo-convex structure, and the aspect ratio of the concavo-convex structure is greater than 2.

[0009] In one embodiment, the transparent electrode includes a transparent insulating layer and a transparent conductive layer, and the concave-convex structure is disposed in the transparent conductive layer.

[0010] In one of the embodiments, the transparent insulating layer includes a light homogenizing unit, and the light homogenizing unit includes parts that are perpendicular to each other.

[0011] In one embodiment, the surface of the transparent insulating layer opposite to the transparent conductive layer is a velvet structure surface capable of trapping light, and an organic protective layer is further included on the transparent insulating layer, and the refractive index of the organic protective layer is between the refractive index of the transparent insulating layer and that of air.

[0012] Compared with the prior art, the present application has the following beneficial effects: by setting a concave-convex structure on the transparent electrode, the proportion of light with a large incident angle entering the perovskite layer is increased, and the utilization rate of light with a large incident angle is improved, thereby improving the photoelectric conversion efficiency. In addition, by setting the refractive index of each layer and further optimizing the concave-convex structure, the probability of light emitting outward is reduced, the reflection loss of light is reduced, and more light is utilized.

Brief Description of the Drawings

[0013] Figure 1 It is a schematic diagram of the structure of a perovskite solar cell in one embodiment of the present application.

[0014] Figure 2 It is a schematic diagram of the light transmission principle of the concave-convex structure of the perovskite solar cell in one embodiment of the present application.

[0015] Figure 3 1 is a schematic diagram of a top view of the structure of a transparent insulating layer including a light homogenization unit in an embodiment of the present application.

[0016] Explanation of reference numerals: 100, transparent electrode; 110, light homogenizing unit; 200, hole transport layer; 300, perovskite layer; 400, electron transport layer; 500, metal electrode layer. [Specific implementation method]

[0017] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. It is to be understood that the specific embodiments described herein are only used to explain the present application, rather than to limit the present application. It should also be noted that, for ease of description, only some structures related to the present application are shown in the accompanying drawings, rather than all structures. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0018] The terms "including" and "having" and any variations thereof in this application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products or devices.

[0019] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0020] Perovskite solar cells have attracted much attention due to their unique material properties and potential high photoelectric conversion efficiency. To realize their commercial application, the photoelectric conversion efficiency of perovskite solar cells must be further improved. Improving the photoelectric conversion efficiency of perovskite solar cells requires comprehensive consideration of factors such as optical design, material properties and manufacturing costs. Through continuous optimization and innovation, this application can achieve efficient, stable and environmentally friendly perovskite solar cells. Please refer to Figure 1 , Figure 1 : is a schematic diagram of the structure of a perovskite solar cell in an embodiment of the present application. The perovskite solar cell in a preferred embodiment of the present application can improve the photoelectric efficiency, including a transparent electrode 100, a hole transport layer 200, a perovskite layer 300, an electron transport layer 400, and a metal electrode layer 500 formed in sequence on the transparent electrode 100. The side of the transparent electrode 100 substrate on which the hole transport layer 200 is formed is a concave-convex structure. Please refer to Figure 2 , Figure 2 It is a schematic diagram of the light transmission principle of the concave-convex structure of the perovskite solar cell in one embodiment of the present application. The concave-convex structure is designed so that when the light has a large incident light angle and irradiates the side wall of the concave-convex structure, if the angle between the light and the normal of the side wall is too large, the light will not enter the hole transport layer 200 by refraction, but will be reflected at the side wall of the concave-convex structure, and the reflected light will continue to propagate. When it reaches the top surface of the concave-convex structure, the angle between the light and the normal of the top surface of the concave-convex structure will meet the refraction requirement, and it can enter the hole transport layer 200, and further enter the perovskite layer 300. Without the concave-convex structure, the light with too large an angle with the normal line is usually difficult to enter the hole transport layer 200, resulting in a decrease in light utilization, so the technical solution of the present application can improve light utilization.

[0021] Light is incident from the transparent electrode 100 into the perovskite solar cell, the concave-convex structure includes a repeated distribution unit shape, and the material of the hole transport layer 200 fills the grooves of the concave-convex structure and covers all surfaces of the concave-convex structure. When light is incident from the transparent electrode 100, passes through the optically transparent interface layer, and enters the core part of the perovskite solar cell, the transparent electrode 100 serves as the entrance of the light, and the concave-convex structure can be composed of repeatedly distributed unit shapes, and each unit shape can be calculated to ensure that the light can be reflected and scattered multiple times on its surface after the incident, so that most of the light can reach the perovskite layer 300, thereby improving the utilization rate of light. At the same time, this structure also increases the contact area between the perovskite layer 300 and the hole transport layer 200, providing more channels for the transmission of charges. The material of the hole transport layer 200 is filled into the grooves of the concave-convex structure and completely covers all surfaces thereof, ensuring that holes can be effectively extracted from the perovskite layer 300 and transmitted to the external circuit, while also preventing the recombination of electrons and holes, thereby improving the energy conversion efficiency of the battery. Through such a design, perovskite solar cells can be significantly improved in terms of light energy absorption, charge transfer and stability.

[0022] In order to further prevent light from being emitted from the inside to the outside, the refractive index of the transparent electrode 100 is smaller than the refractive index of the hole transport layer 200. Since the refractive index of the transparent electrode 100 is smaller than the refractive index of the hole transport layer 200, the light inside is not easily transmitted to the outside. This method can optimize the transmission and utilization efficiency of light energy. By selecting the refractive index, the light inside is prevented from being emitted to the outside, and more light is guided to the perovskite layer 300, thereby improving the absorption efficiency of light energy.

[0023] On the basis of the concave-convex structure, the detail structure can be further optimized to further improve the light utilization rate. The specific method is to set the bottom surface of the groove and the top surface of the convex part in the concave-convex structure as a velvet structure surface that can trap light, and the side of the convex part is selected as a plane. The velvet structure surface is a surface morphology with microscopic undulations and irregularities, but the concave-convex change size of the velvet structure surface is not of the same order of magnitude as the size of the concave-convex structure, and the incident light can be effectively utilized. The velvet structure is adopted on the bottom surface of the groove and the top surface of the convex part of the concave-convex structure. The velvet structure surface is a surface morphology with microscopic undulations and irregularities, which can further effectively allow the incident light to enter the hole transport layer 200, and the side with the convex part is selected as a plane to only keep the side of the convex part to reflect or refract the light in sequence, without causing uncontrollable changes to the direction of the light.

[0024] Specifically, the distance between the interface of the hole transport layer 200 and the perovskite layer 300 and the bottom of the top surface of the convex portion is greater than 30% of the depth of the concave-convex structure, and the aspect ratio of the concave-convex structure is greater than 2. The aspect ratio of the concave-convex structure is designed to be greater than 2. In the vertical direction, the depth of the concave-convex structure is much greater than its width. In this way, the concave-convex structure with a large aspect ratio is not easy for the light transmitted in the convex portion to be transmitted outward from the convex portion again, so that the incident light can be more effectively captured and scattered. In addition, since the carrier transmission rate of the material of the transparent conductive portion is higher, the relevant structural design can be more conducive to collecting carriers in the hole transport layer 200. On the basis of improving the utilization rate of light energy, the conduction capacity can be further improved. By limiting the relevant structural dimensions, the light transmission path and the carrier conduction capacity can be optimized at the same time.

[0025] Specifically, the transparent electrode 100 includes a transparent insulating layer and a transparent conductive layer, the concave-convex structure is arranged in the transparent conductive layer, the transparent insulating layer can be used as the main supporting mechanism, and a transparent conductive layer is further formed on its surface, the thickness of the transparent conductive layer needs to be greater than the height of the convex portion in the concave-convex structure, and after the transparent conductive layer is formed, the concave-convex structure is formed by an etching method, such as a laser etching method, and this step is made before forming other perovskite functional layers, and etching has been completed, etc., and the relevant processing processes and steps do not need to be added to the production line of the perovskite solar cell, and the production line can directly use the transparent electrode 100 with a concave-convex structure, which can directly simplify the production line of the perovskite solar cell, or the existing production line can be compatible with the improved technical solution of the present application without changing it. In addition, for the preparation of the perovskite solar cell, for the scribing in the preparation step, since the present application has already prepared the concave-convex structure in advance, the transparent conductive layer has a thinner layer of transparent conductive material, and the position between the convex portions can be selected during the P1 scribing process, while the P2 scribing and the P3 scribing select the position of the convex portion corresponding to the concave-convex structure. In addition, in order to facilitate alignment, alignment marks can be further integrated in the formed concave-convex structure. Specifically, part of the structure in the concave-convex structure can be selected to form an alignment pattern. Although the formation of the concave-convex structure may add extra steps, integrating it with related usage structures can minimize the process steps and improve production integration and efficiency.

[0026] In order to further improve the utilization rate of light, the present application further provides a light homogenization unit 110 in the transparent insulating layer, see Figure 2 , Figure 2It is a schematic diagram of the top view of the transparent insulating layer including the light homogenizing unit 110 in the embodiment of the present application. The light homogenizing unit 110 includes mutually perpendicular parts. Since the light homogenizing unit 110 is set in the transparent insulating layer, the light passing through the light homogenizing unit 110 can deviate further from the original angle, so as to avoid that the light with too large angle cannot be used. In the specific preparation process, a space for accommodating the light homogenizing unit 110 can be formed by etching in the transparent insulating layer, and then the space etched by the light homogenizing unit 110 is filled to form a transparent insulating layer including the light homogenizing unit 110. In addition, since the surface of the transparent insulating layer also includes a light trapping structure, the normally incident light will not cause additional light to be emitted due to the introduction of the light homogenizing unit 110.

[0027] In addition, in order to protect the battery structure, the surface of the transparent insulating layer opposite to the transparent conductive layer is a velvet structure surface that can trap light, and an organic protective layer is also included on the transparent insulating layer, and the refractive index of the organic protective layer is between the refractive index of the transparent insulating layer and the refractive index of air. The light-trapping structure of the transparent insulating layer can also prevent light from emitting outwards. By matching the organic protective layer and selecting a specific refractive index, the solar cell structure can be protected while preventing light from emitting outwards. In addition, the thickness of the organic protective layer can be controlled to make the layer an anti-reflection film, which can further improve the light utilization rate.

[0028] In order to further illustrate how to realize the structure of the perovskite solar cell defined in the present application, the present application further provides a method for manufacturing a perovskite solar cell, including:

[0029] A transparent electrode 100 including a transparent insulating layer and a transparent conductive layer is provided. The transparent insulating layer can be used as a main supporting mechanism, and a transparent conductive layer is further formed on the surface of the transparent insulating layer.

[0030] A concave-convex structure including repeated distribution unit shapes is formed in the transparent conductive layer. The thickness of the transparent conductive layer needs to be greater than the height of the convex portion in the concave-convex structure. After the transparent conductive layer is formed, the concave-convex structure is formed by laser etching.

[0031] A velvet structure surface capable of trapping light is formed on the transparent insulating layer, specifically a surface morphology with microscopic undulations and irregularities. By adjusting relevant parameters of laser etching, the production of different morphologies is achieved. The size of the concave-convex variation on the velvet structure surface is not on the same order of magnitude as the size of the concave-convex structure, forming a surface morphology with microscopic undulations and irregularities. The velvet structure further effectively allows the incident light to enter the hole transport layer 200.

[0032] A hole transport layer 200 is formed on the concavo-convex structure, wherein the material of the hole transport layer 200 fills the grooves of the concavo-convex structure and covers all surfaces of the concavo-convex structure. The material of the hole transport layer 200 is filled into the grooves of the concavo-convex structure and completely covers all surfaces thereof, thereby ensuring that holes can be effectively extracted from the perovskite layer 300 and transported to an external circuit;

[0033] A perovskite layer 300 , an electron transport layer 400 , and a metal electrode layer 500 are formed on the hole transport layer 200 . The formation method of these specific materials is not further limited in this application, and the materials can be mainstream materials in the current field.

[0034] Specifically, the aspect ratio of the concave-convex structure is greater than 2, and also includes forming a velvet structure surface capable of trapping light on the transparent insulating layer, and further forming an organic protective layer on the surface. In the vertical direction, the depth of the concave-convex structure is much greater than its width. In this way, the concave-convex structure with a large aspect ratio is not easy for the light transmitted in the convex part to be transmitted outward again from the convex part, so that the incident light can be captured and scattered more effectively. By cooperating with the organic protective layer and selecting a specific refractive index, the solar cell structure can be protected while preventing the light from being emitted outward.

[0035] Specifically, the hole transport layer 200 is formed by coating, and is left to stand for more than 1 hour after coating. The coating method can better fill the material in various positions of the concave-convex structure to ensure that the material can be stably attached to the substrate. After coating, in order to ensure that the material can fully penetrate into every detail of the concave-convex structure and form a good combination with the substrate, a standing time of at least 1 hour is arranged, which not only helps the material to fully diffuse and penetrate in the concave-convex structure, but also effectively reduces the performance degradation or defects caused by uneven material flow.

[0036] In the first embodiment, a transparent electrode 100 including a transparent insulating layer and a transparent conductive layer is selected, and a concave-convex structure including a repeated distribution unit shape is formed in the transparent conductive layer by a laser etching method, and a hole transport layer 200 is formed on the concave-convex structure. The material of the hole transport layer 200 fills the grooves of the concave-convex structure and covers all surfaces of the concave-convex structure, and a perovskite layer 300, an electron transport layer 400, and a metal electrode layer 500 are formed on the hole transport layer 200. In this embodiment, no scribing operation is performed.

[0037] Comparative Example 1, based on Example 1, does not form a concave-convex structure by etching.

[0038] The photoelectric conversion efficiency of the formed perovskite solar cell was measured, wherein the incident angle of the light was continuously adjusted for comparison. The incident angle was defined as the angle between the light and the surface of the transparent electrode. Please see Table 1 for specific results.

[0039] Table 1. Photovoltaic conversion efficiency of perovskite solar cells at different light incident angles

[0040] Light Angle 90° 75° 60° 45° 30° Embodiment 1 25.37％ 25.28％ 24.93％ 24.09％ 22.87％ Comparative Example 1 25.32％ 24.96％ 22.56％ 21.63％ 20.22％

[0041] It can be seen from the above structure that the perovskite solar cell with a concave-convex structure has a higher light utilization rate than the perovskite solar cell without a concave-convex structure when the light incident angle is small, reflecting a better photoelectric conversion efficiency.

[0042] As can be seen from the foregoing, the present application provides a high-efficiency perovskite solar cell with an innovative structural design, which forms a concave-convex structure on the transparent electrode to increase the proportion of light with a large incident angle entering the perovskite layer, thereby greatly improving the photoelectric conversion efficiency of the solar cell. The design of the concave-convex structure not only increases the light capture area, but also optimizes the light transmission path, so that light with a large incident angle can be used more effectively.

[0043] In order to further reduce the reflection loss of light, the present invention also reduces the reflection of light at the interface by adjusting the refractive index of each functional layer and combining the optimization of the concave-convex structure. The refractive index matching between the transparent electrode and the hole transport layer, as well as the refractive index adjustment of the light homogenization unit introduced in the transparent insulating layer and the organic protective layer, all help to reduce the probability of light emitting outward, so that more light is absorbed and utilized inside the solar cell.

[0044] The present application also provides in detail a method for preparing such a high-efficiency perovskite solar cell, including steps such as forming a concave-convex structure on a transparent conductive layer, forming a velvet structure surface on a transparent insulating layer, and coating a hole transport layer, which ensures the accuracy and stability of the solar cell structure and provides a reliable preparation process for achieving efficient photoelectric conversion. In summary, the present invention achieves efficient use of light with large incident angles by perovskite solar cells through the design of concave-convex structures and the optimization and regulation of the refractive index of each layer, and significantly improves its photoelectric conversion efficiency.

[0045] The above is only a specific implementation of the present application, and any other improvements made based on the concept of the present application are deemed to be within the protection scope of the present application.

Claims

1. A perovskite solar cell, characterized in that: It comprises a transparent electrode (100), a hole transport layer (200), a perovskite layer (300), an electron transport layer (400), and a metal electrode layer (500) formed in sequence on the transparent electrode (100), and the side of the transparent electrode (100) substrate on which the hole transport layer (200) is formed has a concave-convex structure; Light is incident from the transparent electrode (100) into the perovskite solar cell, the concave-convex structure comprises a repeated distribution unit shape, and the material of the hole transport layer (200) fills the grooves of the concave-convex structure and covers all surfaces of the concave-convex structure.

2. The perovskite solar cell according to claim 1, characterized in that The refractive index of the transparent electrode (100) is smaller than the refractive index of the hole transport layer (200).

3. The perovskite solar cell according to claim 2, characterized in that: The bottom surface of the groove and the top surface of the convex part in the concave-convex structure are velvet structure surfaces capable of trapping light, and the side edge of the convex part is a plane.

4. The perovskite solar cell according to claim 2, characterized in that: The distance between the interface of the hole transport layer (200) and the perovskite layer (300) and the bottom of the top surface of the convex portion is greater than 30% of the depth of the concavo-convex structure, and the aspect ratio of the concavo-convex structure is greater than 2.

5. The perovskite solar cell according to claim 1, characterized in that: The transparent electrode (100) comprises a transparent insulating layer and a transparent conductive layer, and the concave-convex structure is arranged in the transparent conductive layer.

6. The perovskite solar cell according to claim 5, characterized in that: The transparent insulating layer comprises a light homogenizing unit (110), and the light homogenizing unit (110) comprises parts that are perpendicular to each other.

7. The perovskite solar cell according to claim 5, characterized in that: The surface of the transparent insulating layer opposite to the transparent conductive layer is a velvet structure surface capable of trapping light. An organic protective layer is also included on the transparent insulating layer, and the refractive index of the organic protective layer is between the refractive index of the transparent insulating layer and the refractive index of air.

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