Perovskite solar cell and preparation method thereof

Abstract

The invention discloses a perovskite solar cell and a preparation method thereof. The perovskite solar cell may include: a substrate; the FTO layer is arranged on one main surface of the substrate and is of a needle row structure; the first carrier transport layer, the perovskite layer and the second carrier transport layer are sequentially stacked on the FTO layer of the pin row structure; and the perovskite layer is embedded with the faller gill structure and is matched with the faller gill structure. According to the perovskite solar cell, the interface thermal resistance of the perovskite layer can be effectively reduced, and the stress of the perovskite layer caused by temperature difference is reduced, so that the perovskite layer has compact crystal grains, crystal boundary defects are reduced, and the photoelectric conversion efficiency of the perovskite solar cell is effectively improved.

Description

Technical Field

[0001] The present invention relates to a perovskite solar cell and a preparation method thereof. Background Art

[0002] Regarding perovskite solar cells, due to their advantages such as simple process and low manufacturing cost, as well as the gradually increasing photoelectric conversion efficiency, they have attracted more and more attention. Further improving the performance of perovskite solar cells helps to enhance their competitive advantage in the field of photovoltaic cells.

[0003] It is found in research that during the preparation process of perovskite solar cells, due to uneven heating of the perovskite layer in the perovskite solar cell, relatively loose and poor-size-uniformity grains are formed in the perovskite layer, which will cause a large number of interface defects in the perovskite layer and is not conducive to the improvement of the photoelectric conversion efficiency of perovskite solar cells. Summary of the Invention

[0004] In view of this, the present invention provides a perovskite solar cell and a preparation method thereof. The perovskite solar cell can effectively reduce the interfacial thermal resistance of the perovskite layer, reduce the stress caused by temperature difference in the perovskite layer, so that the perovskite layer has dense grains and reduces grain boundary defects, thereby effectively improving the photoelectric conversion efficiency of the perovskite solar cell.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] In a first aspect, an embodiment of the present invention provides a perovskite solar cell, including:

[0007] A substrate;

[0008] An FTO layer with a needle row structure disposed on one main surface of the substrate;

[0009] A first carrier transport layer, a perovskite layer, and a second carrier transport layer sequentially stacked on the FTO layer with the needle row structure;

[0010] The perovskite layer is embedded and matched with the needle row structure.

[0011] In a second aspect, an embodiment of the present invention provides a preparation method for the perovskite solar cell according to the first aspect embodiment, including:

[0012] Step 1, preparing an FTO layer with a needle row structure on one main surface of the substrate;

[0013] Step 2, sequentially stacking and preparing a first carrier transport layer, a perovskite layer, and a second carrier transport layer on the FTO layer with the needle row structure; wherein, the perovskite layer is embedded and matched with the needle row structure.

[0014] The technical solution of the first aspect of the above invention has the following advantages or beneficial effects:

[0015] In the perovskite solar cell provided by the embodiment of the present invention, by arranging an FTO layer with a needle row structure on a main surface of the substrate, and the perovskite layer is embedded and matched with the needle row structure, during the formation of the perovskite layer, the needle row structure is embedded in the perovskite layer, increasing the contact area between the film layers, reducing the voids between the film layers, improving the heat conduction ability of the FTO layer with the needle row structure to the perovskite layer, providing heat for the perovskite layer more evenly, making the perovskite layer heated more uniformly, that is, the temperature of each position rises evenly during the formation of the perovskite layer, so that the crystallization phase transformation of each position is consistent during the formation of the perovskite layer, realizing the uniform crystallization of the perovskite layer, reducing the stress caused by temperature difference inside the perovskite layer, thereby improving the uniformity of the grain size and the compactness of the grain distribution in the perovskite layer, effectively reducing the grain boundary defects and interface defects in the perovskite layer, improving the carrier transport ability, and thus effectively improving the photoelectric conversion efficiency of the perovskite solar cell. Description of the Drawings

[0016] Figure 1 is a schematic cross-sectional structure diagram of a perovskite solar cell according to the prior art;

[0017] Figure 2 is a schematic cross-sectional structure diagram of the first perovskite solar cell provided by the embodiment of the present invention;

[0018] Figure 3 is a schematic cross-sectional structure diagram of the second perovskite solar cell provided by the embodiment of the present invention;

[0019] Figure 4 is a schematic cross-sectional structure diagram of the third perovskite solar cell provided by the embodiment of the present invention;

[0020] Figure 5 is a top view of the FTO layer of the first structure in the perovskite solar cell provided by the embodiment of the present invention;

[0021] Figure 6 is a top view of the FTO layer of the second structure in the perovskite solar cell provided by the embodiment of the present invention;

[0022] Figure 7 is a schematic main process diagram of the preparation method of the perovskite solar cell provided by the embodiment of the present invention;

[0023] Figure 8 is an SEM image of the perovskite layer in the perovskite solar cell of the comparative example;

[0024] Figure 9 It is the SEM image of the perovskite layer in the perovskite solar cell in step D1 of Example 1.

[0025] Reference numerals:

[0026] 10 - Substrate; 20 - FTO layer with needle array structure; 21 - Layered heat-conducting and conductive layer; 22 - Needle-shaped heat-conducting and conductive needle; 20' - Planar structure FTO layer; 30 - First carrier transport layer; 30' - Planar structure first carrier transport layer; 40 - Perovskite layer; 40' - Planar structure perovskite layer; 50 - Second carrier transport layer; 50' - Planar structure second carrier transport layer. Detailed implementation manners

[0027] For perovskite solar cells, currently, various functional layers (such as FTO layer, hole transport layer, perovskite layer, and electron transport layer, etc.) are mainly set on the plane of the substrate, so that each functional layer is also approximately in a planar structure. Figure 1 Exemplarily shows the main structure of the existing perovskite solar cell. As Figure 1 shown, in the existing perovskite solar cell, a planar structure FTO layer 20', a planar structure first carrier transport layer 30', a planar structure perovskite layer 40', and a planar structure second carrier transport layer 50' are sequentially stacked on a main surface of the substrate 10. During the formation of the planar structure perovskite layer 40', the substrate 10 is heated by a heating table, and the substrate 10 transfers heat to the planar structure perovskite layer 40' through the planar structure FTO layer 20' and the planar structure first carrier transport layer 30'. It is found that after the thickness of the planar structure perovskite layer 40' reaches a certain thickness, due to the existence of the planar structure first carrier transport layer 30' between the planar structure FTO layer 20' and the planar structure perovskite layer 40', and there are relatively many voids between the planar structure FTO layer 20' and the planar structure first carrier transport layer 30', and there will also be relatively many voids between the planar structure first carrier transport layer 30' and the planar structure perovskite layer 40'. The existence of voids, the poor thermal conductivity of the air in the voids, and the relatively many voids reduce the rate of heat transfer from the planar structure FTO layer 20' to the planar structure perovskite layer 40'. During the process of perovskite solution crystallization to form the planar structure perovskite layer 40', from the bottom to the top direction of the planar structure perovskite layer 40', the temperature is uneven, resulting in uneven crystallization of the perovskite solution from the bottom to the top direction of the planar structure perovskite layer 40', with differences. And the differences in perovskite solution crystallization will cause relatively large stress in the planar structure perovskite layer 40', forming relatively loose and poor-size-uniformity grains, which will cause a large number of interface defects in the planar structure perovskite layer 40', and is not conducive to improving the photoelectric conversion efficiency of the perovskite solar cell.

[0028] To solve the above-mentioned defects and problems existing in the structures of existing perovskite solar cells, embodiments of the present invention provide a perovskite solar cell with a novel structure and a preparation method thereof. Among them, Figures 2 to 4 shows a schematic cross-sectional structure diagram of the perovskite solar cell provided by the embodiment of the present invention; Figure 5 and Figure 6 shows a top view of different arrangement modes of the FTO layer 20 with a needle row structure.

[0029] The FTO layer with a needle row structure involved in the embodiment of the present invention refers to a needle-shaped fluorine-doped tin oxide (F-doped Tin Oxide, FTO) layer formed on the substrate 10.

[0030] The two structures being fitted together involved in the embodiment of the present invention means that a part of one structure extends into another structure. Exemplarily, the needle-shaped structure included in the FTO layer 20 with a needle row structure extends into the perovskite layer 40, so that the perovskite layer 40 includes grooves matching the needle-shaped structure.

[0031] It should be noted that the perovskite solar cell provided by the embodiment of the present invention can be used as an independent battery, and it can also be used as a part of a tandem battery.

[0032] Specifically, as Figures 2 to 4 shown, the perovskite solar cell provided by the embodiment of the present invention may include:

[0033] a substrate 10;

[0034] an FTO layer 20 with a needle row structure disposed on a main surface of the substrate 10;

[0035] a first carrier transport layer 30, a perovskite layer 40, and a second carrier transport layer 50 sequentially stacked on the FTO layer 20 with a needle row structure;

[0036] The perovskite layer 40 is fitted together with the needle row structure and matches the needle row structure.

[0037] Among them, the substrate 10 may be glass, graphene, carbon nanotubes, etc.

[0038] For the FTO layer 20 with a needle row structure provided by the embodiment of the present invention, it can be formed synchronously during the preparation process of the substrate 10, or can be formed after the substrate 10. In addition, the FTO layer 20 with a needle row structure can be obtained by laser etching on the basis of a planar structure FTO layer, and the existing production process of perovskite solar cells can be continued to effectively control the production cost of perovskite solar cells.

[0039] Among them, the first charge carrier transport layer 30 can be a hole transport layer. Correspondingly, the second charge carrier transport layer 50 is an electron transport layer. Additionally, the first charge carrier transport layer 30 can also be an electron transport layer. Correspondingly, the second charge carrier transport layer 50 is a hole transport layer. Preferably, the first charge carrier transport layer 30 is a hole transport layer, and the second charge carrier transport layer 50 is an electron transport layer. Among them, the thickness of the first charge carrier transport layer 30 can be 10 nm to 30 nm, and the second charge carrier transport layer 50 can be 20 nm to 50 nm. Exemplarily, the thickness of the first charge carrier transport layer 30 can be 10 nm, 12 nm, 15 nm, 18 nm, 20 nm, 23 nm, 25 nm, 28 nm, or 30 nm. The second charge carrier transport layer 50 can be 20 nm, 23 nm, 25 nm, 28 nm, 30 nm, 32 nm, 35 nm, 37 nm, 40 nm, 43 nm, 45 nm, 48 nm, or 50 nm, etc.

[0040] Furthermore, in order to ensure that the perovskite layer 40 is fitted with the needle row structure, the first charge carrier transport layer 30 is fitted with the needle row structure and is matched with the needle row structure. As Figures 2 to 4 shown, the first charge carrier transport layer 30 also has a needle row structure. Correspondingly, the perovskite layer 40 being fitted with the needle row structure is essentially the perovskite layer 40 being fitted into the needle row structure of the first charge carrier transport layer 30, so as to effectively reduce the gap between the perovskite layer 40 and the first charge carrier transport layer 30, improve the contact and contact area between the FTO layer 20, the first charge carrier transport layer 30, and the perovskite layer 40 of the needle row structure at each position, reduce the gap between the interfaces, and reduce the existence of the air layer between the interfaces. Compared with air, FTO has higher thermal conductivity, and FTO has a higher thermal conductivity coefficient than perovskite. Through this needle row structure, the heat conduction from the FTO layer 20 of the needle row structure to the perovskite layer 40 can be effectively improved, so as to reduce the thermal resistance between the FTO layer 20 of the needle row structure and the perovskite layer 40.

[0041] Regarding Figures 2 to 4The provided perovskite solar cell is configured such that an FTO layer 20 with a needle array structure is disposed on a main surface of a substrate 10, and the perovskite layer 40 is fitted and matched with the needle array structure. During the formation of the perovskite layer 40, the needle array structure is embedded in the perovskite layer 40, increasing the contact area between the film layers, reducing the voids between the film layers, enhancing the heat conduction ability of the FTO layer 20 with the needle array structure to the perovskite layer 40, providing heat to the perovskite layer 40 more evenly, enabling the perovskite layer 40 to be heated more uniformly, that is, each position is uniformly heated during the formation of the perovskite layer 40, ensuring that the crystallization phase change at each position is consistent during the formation of the perovskite layer 40, achieving uniform crystallization of the perovskite layer 40, reducing the stress caused by temperature difference inside the perovskite layer 40, thereby enhancing the uniformity of the grain size and the compactness of the grain distribution in the perovskite layer 40, effectively reducing the grain boundary defects and interface defects in the perovskite layer 40, enhancing the carrier transport ability, and thus effectively improving the photoelectric conversion efficiency of the perovskite solar cell.

[0042] The core of the perovskite solar cell provided by the embodiment of the present invention lies in: the FTO layer 20 with a needle array structure. The FTO layer 20 with a needle array structure will be described in detail below.

[0043] Specifically, as Figures 2 to 4 shown, the FTO layer 20 with a needle array structure may include: a layered thermally and electrically conductive layer 21 that is matched and adhered to the main surface of the substrate 10, and needle-shaped thermally and electrically conductive needles 22 arranged on the layered thermally and electrically conductive layer 21; the layered thermally and electrically conductive layer 21 and the needle-shaped thermally and electrically conductive needles 22 are an integral structure; the perovskite layer 40 covers the layered thermally and electrically conductive layer 21 and is fitted with the needle-shaped electrically and thermally conductive needles 22.

[0044] By covering the layered thermally and electrically conductive layer 21 with the perovskite layer 40 and fitting it with the needle-shaped electrically and thermally conductive needles 22, the layered thermally and electrically conductive layer 21 conducts heat for a part of the perovskite layer 40 covering it, and simultaneously conducts heat for the part of the perovskite layer 40 fitted to the needle-shaped electrically and thermally conductive needles 22 through the needle-shaped electrically and thermally conductive needles 22. Since the FTO material has good thermal conductivity, the layered thermally and electrically conductive layer 21 and the needle-shaped thermally and electrically conductive needles 22 can uniformly supply heat to the perovskite layer 40, enabling the entire perovskite layer 40 to be heated uniformly, ensuring that the perovskite layer 40 forms relatively uniform and dense grains, reducing the grain boundary defects and interface defects in the perovskite layer 40, and thus effectively improving the photoelectric conversion efficiency of the perovskite solar cell.

[0045] Among them, the layered thermally and electrically conductive layer 21 and the needle-shaped thermally and electrically conductive needles 22 being an integral structure can ensure the coherence of the FTO layer 20 with a needle array structure, so as to ensure the coherence and integrity of the subsequent prepared first carrier transport layer 30, perovskite layer 40, and second carrier transport layer 50, and reduce the defects of the perovskite solar cell.

[0046] In addition, on the premise of the FTO layer 20 of the needle row structure, the above-mentioned substrate 10 can be a planar structure or a pyramid textured structure. It should be noted that there is no mutual restriction between the pyramid textured structure of the substrate 10 and the needle row structure of the FTO layer 20 of the needle row structure. The needle-shaped thermally conductive and electrically conductive needles 22 can be located at the top of the pyramid textured structure of the substrate 10 or between the bottoms of two pyramids.

[0047] Compared with the FTO layer that forms a pyramid textured structure only based on the pyramid textured structure of the substrate 10 (since the pyramid textured structure can make the thickness of the formed FTO layer uneven, the thickness of the area at the top of the pyramid fluff structure in the FTO layer is thinner, which will lead to a larger resistance, and there are obvious differences in the carrier transmission between the thinner FTO layer area and the thicker FTO layer area, which will make the current transmission uneven), whether it is the substrate 10 based on a planar structure or the substrate 10 based on a textured structure, the FTO layer 20 of the needle row structure provided by the embodiments of the present invention is more controllable and can ensure the uniformity of the FTO layer 20 of the needle row structure and the uniformity of current transmission. In addition, the FTO layer 20 of the needle row structure provided by the embodiments of the present invention mainly transmits carriers through the layered thermally conductive and electrically conductive layer 21, which can ensure the uniformity of carrier transmission.

[0048] More specifically, in order to further improve the uniformity of heat transfer, as Figures 2 to 4 and Figure 5 and Figure 6 shown, among the needle-shaped thermally conductive and electrically conductive needles 22 arranged on the layered thermally conductive and electrically conductive layer 21, the distance D between every two adjacent needle-shaped thermally conductive and electrically conductive needles 22 is 1 μm to 2 μm. Exemplarily, the distance between every two adjacent needle-shaped thermally conductive and electrically conductive needles 22 can be 1 μm, 1.2 μm, 1.4 μm, 1.5 μm, 1.7 μm, 1.8 μm or 2 μm, etc. By controlling the distance between every two adjacent needle-shaped thermally conductive and electrically conductive needles 22, it can be ensured that the heat transferred by the FTO layer 20 of the needle row structure can reach each position of the perovskite layer 40 evenly, and the uniformity and denseness of the grains in the perovskite layer 40 are improved. It should be noted that the distance D between every two adjacent needle-shaped thermally conductive and electrically conductive needles 22 refers to the distance between the adjacent edges that are close to each other among the two adjacent needle-shaped thermally conductive and electrically conductive needles 22.

[0049] It should be noted that the cross-section of the needle-shaped thermally conductive and electrically conductive needle 22 can be of any shape, Figure 5 and Figure 6 and only an example is given that the cross-section of the needle-shaped thermally conductive and electrically conductive needle 22 is circular. For example, the cross-section of the needle-shaped thermally conductive and electrically conductive needle 22 can also be rectangular, oval or polygonal, etc.

[0050] Preferably, the distance D between every two adjacent needle-shaped thermally conductive and electrically conductive needles 22 is twice the thickness of the perovskite layer 40.

[0051] Further, as Figures 2 to 4 and Figure 5 and Figure 6 shown, the width d of the needle-shaped thermally and electrically conductive needles 22 arranged on the layered thermally and electrically conductive layer 21 can be 0.3 μm to 0.8 μm. Exemplarily, the width d of the needle-shaped thermally and electrically conductive needles 22 can be 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, or 0.8 μm, etc. By restricting the width d of the needle-shaped thermally and electrically conductive needles 22, uniform heat transfer can be ensured, and the subsequent carrier transport rate can be ensured. It should be noted that the width d of the needle-shaped thermally and electrically conductive needles 22 generally refers to the distance at the widest position of the cross-section of the needle-shaped thermally and electrically conductive needles 22. As Figure 5 and Figure 6 shown, for a structure with a circular cross-section, the width d of the needle-shaped thermally and electrically conductive needles 22 is the diameter of the circle.

[0052] More specifically, the height of the needle-shaped thermally and electrically conductive needles 22 can be 0.3 μm to 0.5 μm. Exemplarily, the height of the needle-shaped thermally and electrically conductive needles 22 can be 0.3 μm, 0.35 μm, 0.4 μm, 0.45 μm, or 0.5 μm, etc. By restricting the height of the needle-shaped thermally and electrically conductive needles 22, even when the perovskite layer 40 is prepared on the basis of the first carrier transport layer 30, it can be ensured that the perovskite layer 40 is embedded in the needle-shaped thermally and electrically conductive needles 22, improving the heat uniformity of the perovskite layer 40.

[0053] The thickness of the layered thermally and electrically conductive layer 21 can be 0.2 μm to 0.6 μm. Exemplarily, the thickness of the layered thermally and electrically conductive layer 21 can be 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, or 0.6 μm, etc. By restricting the thickness of the layered thermally and electrically conductive layer 21, the electrical conductivity uniformity of the FTO layer 20 in the needle row structure can be ensured, and in cooperation with the needle-shaped thermally and electrically conductive needles 22, it can be ensured that the needle-shaped thermally and electrically conductive needles 22 can be effectively stabilized, thereby improving the reliability of the perovskite solar cell.

[0054] In addition, the layered thermally and electrically conductive layer 21 and the needle-shaped thermally and electrically conductive needles 22 can be formed by using a laser device to perform multi-directional grooving on the formed layered FTO layer. Exemplarily, the layered FTO layer can be transversely and longitudinally cross-grooved by a laser device to obtain the Figure 5 or Figure 6 shown structure. It should be noted that the arrangement of the needle-shaped thermally and electrically conductive needles 22 can also be arranged in other forms, as long as the distance D between every two adjacent needle-shaped thermally and electrically conductive needles 22 satisfies 1 μm to 2 μm and the width d of the needle-shaped thermally and electrically conductive needles 22 can be 0.3 μm to 0.8 μm.

[0055] Among them, the thickness of the perovskite layer 40 can be 0.6 μm to 0.8 μm. Exemplarily, the thickness of the perovskite layer 40 can be 0.6 μm, 0.7 μm, 0.8 μm, etc. By controlling the thickness of the perovskite layer 40 to cooperate with the layered thermally and electrically conductive layer 21 and the needle-shaped thermally and electrically conductive needles 22, it is ensured that the perovskite layer 40 can completely cover the needle-shaped thermally and electrically conductive needles 22, ensuring the integrity of the perovskite layer 40 to effectively improve carrier transport.

[0056] In addition, the structure of the perovskite layer 40 can be Figure 4 the planar structure shown, or can be Figure 2 and Figure 3 the needle row structure corresponding to the needle row structure of the FTO layer 20 shown.

[0057] Furthermore, the structure of the second carrier transport layer 50 can be Figure 3 and Figure 4 the planar structure shown, or can be Figure 2 the needle row structure corresponding to the needle row structure of the FTO layer 20 shown.

[0058] Furthermore, an embodiment of the present invention also provides a method for manufacturing a perovskite solar cell. As Figure 7 shown, the method for manufacturing the perovskite solar cell may include:

[0059] Step S701: Prepare a needle row structure FTO layer 20 on one main surface of the substrate 10.

[0060] For this step, the specific implementation may include: forming a layered FTO layer on the main surface of the substrate 10 by a deposition method; performing multi-directional grooving on the layered FTO layer to form a layered thermally and electrically conductive layer 21 that matches and fits the main surface of the substrate 10 and needle-shaped thermally and electrically conductive needles 22 arranged on the layered thermally and electrically conductive layer 21.

[0061] Among them, the layered FTO layer can be a single-layer thin film structure or a stacked structure formed by multiple thin films.

[0062] Step S702: Sequentially stack and prepare a first carrier transport layer 30, a perovskite layer 40, and a second carrier transport layer 50 on the needle row structure FTO layer 20; among them, the perovskite layer 40 is embedded and matched with the needle row structure.

[0063] Specifically, the specific implementation of this step may include: sequentially spin-coating a solution of the first charge transport layer 30 and a perovskite precursor solution on the FTO layer 20 of the needle array structure, and then annealing at a temperature of 100°C to 150°C for 10 min to 20 min to obtain the first charge transport layer 30 and the perovskite layer 40. The second charge transport layer 50 is spin-coated on the perovskite layer 40 and dried. Exemplarily, the annealing temperature during the formation process of the perovskite layer 40 can be 100°C, 110°C, 120°C, 130°C, 140°C, or 150°C. The annealing treatment time can be 10 min, 12 min, 15 min, 18 min, or 20 min, etc. By sequentially spin-coating the solution of the first charge transport layer 30 and the perovskite precursor solution and then annealing, the heat uniformity of the perovskite precursor solution can be further improved, so that the crystallization phase transformation at each position during the formation of the perovskite layer 40 is consistent, realizing the uniform crystallization of the perovskite layer 40 and reducing the stress caused by the temperature difference inside the perovskite layer 40.

[0064] That is, by forming the FTO layer 20 with a needle array structure on one main surface of the substrate 10 and making the prepared perovskite layer 40 fit and match with the FTO layer 20 with a needle array structure, during the formation of the perovskite layer 40, the FTO layer 20 with a needle array structure is embedded in the perovskite layer 40, increasing the contact area between the film layers, reducing the voids between the film layers, improving the heat conduction ability of the FTO layer 20 with a needle array structure to the perovskite layer 40, providing heat for the perovskite layer 40 more evenly, so that each position of the perovskite layer 40 is heated evenly, that is, each position is heated evenly during the formation of the perovskite layer 40, making the crystallization phase transformation at each position during the formation of the perovskite layer 40 consistent, realizing the uniform crystallization of the perovskite layer 40, reducing the stress caused by the temperature difference inside the perovskite layer 40, thereby improving the uniformity of the grain size and the compactness of the grain distribution in the perovskite layer 40, effectively reducing the grain boundary defects and interface defects of the perovskite layer 40, improving the charge carrier transport ability, and thus effectively improving the photoelectric conversion efficiency of the perovskite solar cell.

[0065] The following is described in detail with several examples and a comparative example.

[0066] Example 1:

[0067] Step A1: Provide a glass substrate and deposit an FTO layer on the glass substrate by CVD.

[0068] Step B1: Use a laser device to slot the FTO layer. The slot width is 1 μm; the slot pitch is 0.3 μm.

[0069] Step C1: Cut the prepared glass / FTO substrate into the required size.

[0070] Step D1: Sequentially prepare a hole transport layer (SAM) and a perovskite layer with a thickness of 0.6 μm on a glass / FTO substrate, and anneal at a temperature of 150 °C for 20 min.

[0071] Step E1: Sequentially prepare C60, BCP, and a silver electrode on the perovskite layer to form a complete perovskite solar cell structure.

[0072] Example 2:

[0073] Step A2, Step C2, and Step E3 are exactly the same as those in Example 1.

[0074] The differences from Example 1 are as follows: In Step B2, the slot width is 1.3 μm; the slot pitch is 0.5 μm. The thickness of the perovskite layer prepared in Step D2 is 0.7 μm.

[0075] Example 3:

[0076] Step A3, Step C3, and Step E3 are exactly the same as those in Example 1.

[0077] The differences from Example 1 are as follows: In Step B3, the slot width is 1.5 μm; the slot pitch is 0.8 μm. The thickness of the perovskite layer prepared in Step D2 is 0.7 μm.

[0078] Example 4:

[0079] Step A3, Step C3, and Step E3 are exactly the same as those in Example 1.

[0080] The differences from Example 1 are as follows: In Step B3, the slot width is 1.6 μm; the slot pitch is 0.8 μm. The thickness of the perovskite layer prepared in Step D2 is 0.8 μm.

[0081] Example 5:

[0082] Step A3, Step C3, and Step E3 are exactly the same as those in Example 1.

[0083] The differences from Example 1 are as follows: In Step B3, the slot width is 1.8 μm; the slot pitch is 0.8 μm. The thickness of the perovskite layer prepared in Step D2 is 0.9 μm.

[0084] Example 6:

[0085] Step A3, Step C3, and Step E3 are exactly the same as those in Example 1.

[0086] The differences from Example 1 are as follows: In Step B3, the slot width is 2 μm; the slot pitch is 0.8 μm. The thickness of the perovskite layer prepared in Step D2 is 0.9 μm.

[0087] Comparative Example:

[0088] Step A: Provide a glass substrate, and deposit a planar FTO layer on the glass substrate by CVD.

[0089] Step B: Cut the prepared glass / FTO substrate into the required size.

[0090] Step C: Sequentially prepare a hole transport layer (SAM) and a perovskite layer with a thickness of 0.6 μm on the glass / FTO substrate, and anneal at a temperature of 150 °C for 20 min.

[0091] Step D: Sequentially prepare C60, BCP, and silver electrodes on the perovskite layer to form a complete perovskite solar cell structure.

[0092] Perform performance tests on the perovskite solar cells prepared in Examples 1 to 6 and the comparative example. The test results are shown in Table 1.

[0093] Table 1

[0094] <![CDATA[V oc (V)]]> <![CDATA[J sc (mA / cm 2 )]]> FF (%) PCE (%) Comparative Example 1.130 25.58 71.02 20.54 Example 1 1.136 26.15 77.97 23.18 Example 2 1.140 26.20 77.71 23.23 Example 3 1.149 26.39 80.11 24.31 Example 4 1.159 26.51 82.83 25.47 Example 5 1.150 27.06 77.41 24.11 Example 6 1.140 25.81 77.33 23.13

[0095] As can be seen from Table 1 above, compared with the comparative example, the open-circuit voltage (V OC ), short-circuit current (J SC ), fill factor (FF), and photoelectric conversion efficiency (PCE) of Examples 1 to 6 have all been improved to varying degrees, indicating that the technical solution provided by the embodiments of the present invention can effectively improve the performance of perovskite solar cells.

[0096] Furthermore, it can also be seen from Table 1 that compared with the case where the slot width does not reach 2 times the thickness of the perovskite layer (Example 2) and the case where the slot width exceeds 2 times the thickness of the perovskite layer (Examples 1, 3, and 6), when the slot width is 2 times the thickness of the perovskite layer (Examples 4 and 5), the difference in parameter improvement is relatively large. Exemplarily, the open-circuit voltage, fill factor, and photoelectric conversion efficiency of Example 4 have been significantly improved, but the short-circuit current is the same as that of Example 6, and there is a significant improvement compared with the short-circuit current of Examples 1 to 3. The open-circuit voltage and short-circuit current of Example 5 have been significantly improved, but the fill factor and photoelectric conversion efficiency are relatively low. This shows that although a slot width of 2 times the thickness of the perovskite layer can improve the performance of perovskite solar cells, the structure of the perovskite solar cells provided by the embodiments of the present invention is not only affected by the relationship between the slot width and the thickness of the perovskite layer, but also affected by factors such as the thickness of the perovskite layer.

[0097] Furthermore, it can be seen from the comparison between Example 4 and Example 5 that the current density increases with the increase in the thickness of the perovskite layer and the improvement of crystallization. When the thickness of the perovskite thin film reaches 0.8 μm (800 nm), the photoelectric conversion efficiency (PCE) of Example 4 is the highest. After the thickness of the perovskite thin film exceeds 800 nm (Example 5), although the current density may increase slightly (the short-circuit current increases), due to the relatively difficult carrier transport, the fill factor and open-circuit voltage of Example 5 are relatively low.

[0098] In addition, SEM images of the planar regions of the perovskite layer obtained in step D1 of Example 1 and the perovskite layer obtained in the comparative example were taken by a scanning electron microscope (SEM). Among them, Figure 8 is the SEM image of the planar region of the perovskite layer obtained in the comparative example; Figure 9 is the SEM image of the planar region of the perovskite layer obtained in step D1 of Example 1 of the present invention. By comparing Figure 8 and Figure 9 it can be clearly seen that the perovskite layer obtained in the comparative example has poor crystallization uniformity, while the perovskite layer obtained in step D1 of Example 1 of the present invention has a uniform crystal structure, relatively uniform grain size, and dense grain distribution. This also further shows that the technical solution provided by the embodiments of the present invention can effectively achieve uniform crystallization of the perovskite layer, improve the uniformity of grain size and the density of grain distribution in the perovskite layer. Combining with the test results given in Table 1, it shows that the improvement of the perovskite layer performance can effectively reduce the grain boundary defects and interface defects of the perovskite layer, improve the carrier transport ability, and thus effectively improve the photoelectric conversion efficiency of the perovskite solar cell.

[0099] The introduction provided in the above steps is only used to help understand the structure, method and core idea of the present invention. For those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A perovskite solar cell, characterized in that, Comprising: a substrate (10); an FTO layer (20) with a needle row structure disposed on one main surface of the substrate (10); a first carrier transport layer (30), a perovskite layer (40), and a second carrier transport layer (50) sequentially stacked on the FTO layer (20) with the needle row structure; the perovskite layer (40) is fitted and matched with the needle row structure.

2. The perovskite solar cell according to claim 1, wherein The FTO layer (20) with the needle row structure comprises: a layered thermally conductive and electrically conductive layer (21) that is matched and adhered to the main surface of the substrate (10), and needle-shaped thermally conductive and electrically conductive needles (22) arranged on the layered thermally conductive and electrically conductive layer (21); the layered thermally conductive and electrically conductive layer (21) and the needle-shaped thermally conductive and electrically conductive needles (22) are an integral structure; the perovskite layer (40) covers the layered thermally conductive and electrically conductive layer (21) and is fitted with the needle-shaped conductive and thermally conductive needles (22).

3. The perovskite solar cell according to claim 2, wherein among the needle-shaped thermally conductive and electrically conductive needles (22) arranged on the layered thermally conductive and electrically conductive layer (21), the distance between every two adjacent needle-shaped thermally conductive and electrically conductive needles (22) is 1 μm to 2 μm; preferably, the distance between every two adjacent needle-shaped thermally conductive and electrically conductive needles (22) is twice the thickness of the perovskite layer (40); and / or the width of the needle-shaped thermally conductive and electrically conductive needles (22) arranged on the layered thermally conductive and electrically conductive layer (21) is 0.3 μm to 0.8 μm; and / or the thickness of the layered thermally conductive and electrically conductive layer (21) is 0.2 μm to 0.6 μm.

4. The perovskite solar cell according to claim 2 or 3, wherein the layered thermally conductive and electrically conductive layer (21) and the needle-shaped thermally conductive and electrically conductive needles (22) are formed by multi-directional grooving of the formed layered FTO layer using a laser device.

5. The perovskite solar cell according to claim 3, wherein the thickness of the perovskite layer (40) is 0.6 μm to 0.8 μm.

6. The perovskite solar cell according to claim 1 or 2, wherein the first carrier transport layer (30) is a hole transport layer, and the second carrier transport layer (50) is an electron transport layer.

7. The perovskite solar cell according to claim 1, wherein the first carrier transport layer (30) is fitted and matched with the needle row structure.

8. The perovskite solar cell according to claim 7, wherein the thickness of the first carrier transport layer (30) is 10 nm to 30 nm.

9. The preparation method of the perovskite solar cell according to any one of claims 1 to 8, characterized in that, Comprising: Step 1, preparing an FTO layer (20) with a needle row structure on one main surface of a substrate (10); Step 2, sequentially stacking and preparing a first carrier transport layer (30), a perovskite layer (40), and a second carrier transport layer (50) on the FTO layer (20) with the needle row structure; wherein, the perovskite layer (40) is fitted and matched with the needle row structure.

10. The preparation method according to claim 9, wherein, Step 1 includes: forming a layered FTO layer on the main surface of the substrate (10) by a deposition method; Perform multi-directional grooving on the layered FTO layer to form a layered thermally conductive and electrically conductive layer (21) that matches and adheres to the main surface of the substrate (10), and needle-shaped thermally conductive and electrically conductive needles (22) arranged on the layered thermally conductive and electrically conductive layer (21).

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