Perovskite solar cell with high photoelectric conversion efficiency and preparation method thereof

Abstract

The application relates to the technical field of solar cells, in particular to a perovskite solar cell with high photoelectric conversion efficiency and a preparation method thereof. The application discloses a perovskite solar cell with high photoelectric conversion efficiency, which comprises an n-i-p formal structure or a p-i-n reverse structure, the n-i-p formal structure comprises a transparent substrate, a transparent conductive film layer, an electron transport layer, a perovskite layer, a hole transport layer and an electrode layer are sequentially arranged on the transparent substrate, a reflection reduction film layer is arranged on the other side of the transparent substrate, and an optical matching film layer is arranged on the electron transport layer or the hole transport layer and arranged between the transparent conductive film layer and the electron transport layer or between the transparent conductive film and the hole transport layer. The perovskite solar cell prepared by the application increases the light transmittance of the perovskite layer, thereby improving the photoelectric conversion efficiency of the perovskite solar cell.

Description

Technical Field

[0001] This invention relates to the field of solar cell technology, and in particular to a perovskite solar cell with high photoelectric conversion efficiency and its preparation method. Background Technology

[0002] Perovskite solar cells have seen rapid development over the past decade. Since their first fabrication in 2009, the photoelectric conversion efficiency of small-area laboratory samples has increased dramatically from 3.8% to 25.2%, approaching the efficiency of silicon-based solar cells. Compared to traditional silicon-based solar cells, perovskite solar cells offer advantages such as readily available and inexpensive raw materials, low energy consumption, a wide and adjustable bandgap, a short and simple fabrication process, low cost, and the ability to be stacked with other solar cell systems made of different materials, making them one of the most promising solar cell technologies currently available.

[0003] To improve the photoelectric conversion efficiency of perovskite solar cells, researchers have focused on the selection of perovskite materials for the light-absorbing layer, grain growth, process control, and the interface and potential matching between different film layers, achieving significant results. However, current perovskite solar cells still suffer from low photoelectric conversion efficiency. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, the present invention provides a perovskite solar cell with high photoelectric conversion efficiency and its preparation method, thereby improving the photoelectric conversion efficiency of the perovskite solar cell by increasing the transmittance incident on the perovskite layer.

[0005] The technical solution adopted by this invention to solve its technical problem is:

[0006] A perovskite solar cell with high photoelectric conversion efficiency includes a nip formal structure or a pin inverse structure.

[0007] The formal structure of NIP includes a transparent substrate, on which a transparent conductive film layer, an electron transport layer, a perovskite layer, a hole transport layer, and an electrode layer are sequentially disposed.

[0008] The pin inverted structure includes a transparent substrate, on which a transparent conductive film layer, a hole transport layer, a perovskite layer, an electron transport layer, and an electrode layer are sequentially disposed.

[0009] An anti-reflective coating is provided on the other side of the transparent substrate;

[0010] The battery further includes an optical matching film layer, which is disposed between the transparent conductive film layer and the electron transport layer or the transparent conductive film and the hole transport layer, or the optical matching film layer is disposed on the electron transport layer or the hole transport layer.

[0011] Furthermore, the materials of the perovskite layer include, but are not limited to, methylamine iodide perovskite, formamidinium iodide perovskite, cesium lead iodide, and methylamine bromide perovskite.

[0012] Furthermore, the thickness of the perovskite layer is 400-2000 nm.

[0013] Furthermore, the antireflective coating is composed of alternating layers of high-refractive-index and low-refractive-index materials.

[0014] Furthermore, the high refractive index material has a refractive index of 1.8-2.8, and the low refractive index material has a refractive index of 1.3-1.7.

[0015] Furthermore, the high refractive index materials include, but are not limited to, titanium dioxide, niobium pentoxide, tantalum pentoxide, zirconium dioxide, silicon nitride, aluminum nitride, zinc oxide, and indium tin oxide (ITO); the low refractive index materials include, but are not limited to, silicon dioxide, aluminum oxide, magnesium fluoride, and calcium fluoride.

[0016] Furthermore, the antireflective coating has 4-10 layers, and the total thickness of the antireflective coating is 50-800 nm.

[0017] Furthermore, the materials of the optical matching film include, but are not limited to, silicon dioxide, magnesium fluoride, organosilicon, silicon-doped zinc oxide, and magnesium-doped zinc oxide.

[0018] Furthermore, the refractive index of the optical matching film is 1.3-1.7.

[0019] The method for preparing the perovskite solar cell described above includes the following steps:

[0020] 1) Designed according to the conventional perovskite solar cell structure;

[0021] 2) An anti-reflective coating is provided on the other side of the transparent substrate;

[0022] 3) An optical matching film is provided between the transparent conductive film layer and the electron transport layer or between the transparent conductive film and the hole transport layer, or an optical matching film is provided on the electron transport layer or the hole transport layer to increase the transmittance of light incident on the perovskite layer.

[0023] The beneficial effects of this invention are:

[0024] This application improves the light transmittance incident on the perovskite layer by providing an anti-reflection film layer on the other side of a transparent substrate, and providing an optical matching film layer between the transparent conductive film layer and the electron transport layer or the transparent conductive film layer and the hole transport layer, or providing an optical matching film layer on top of the electron transport layer or the hole transport layer; thereby increasing the light transmittance incident on the perovskite layer by 5-10% and improving the photoelectric conversion efficiency of the perovskite solar cell by 2-3%. Attached Figure Description

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0026] Figure 1 This is a schematic diagram of the perovskite solar cell with the nip formal structure described in this application;

[0027] Figure 2 This is a schematic diagram of the perovskite solar cell with a pin-inverted structure as described in this application;

[0028] Figure 3 This is a schematic diagram of the structure of the perovskite solar cell in Embodiment 1 of this application;

[0029] Figure 4 This is a schematic diagram of the structure of the perovskite solar cell in Embodiment 2 of this application;

[0030] Figure 5 This is a schematic diagram of the structure of the perovskite solar cell in Embodiment 3 of this application. Detailed Implementation

[0031] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments. The content mentioned in the embodiments is not intended to limit the present invention.

[0032] As used herein, “and / or” includes all combinations of any and one or more of the associated listed items. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular forms “a,” “an,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. Further understanding is needed; when used in this specification, “comprising” designates the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof.

[0033] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Further understanding is that terms, such as those defined in common dictionaries, are interpreted in accordance with their meaning in the context of the relevant field and are not idealized or overly formal, unless expressly defined herein.

[0034] The exemplary invention described herein may suitably omit any one or more limiting elements, which are not specifically disclosed herein. Therefore, terms such as “comprising,” “including,” “containing,” etc., should be interpreted broadly and non-limitingly. Furthermore, the terminology used herein is for descriptive purposes without limitation, and it is unintentional to use terms that do not include any equivalent characteristics, but only to describe a portion of their characteristics; however, various modifications are possible within the scope of the invention according to the claims. Therefore, while the invention has been specifically disclosed through preferred embodiments and optional features, variations of the invention embodied by the modifications disclosed herein may be noted by those skilled in the art, and such modifications and variations are considered to be within the scope of the invention.

[0035] All raw materials or reagents used in the embodiments and comparative examples of this invention were purchased from mainstream manufacturers on the market. Those without specified manufacturers or concentrations are all analytical grade raw materials or reagents that are routinely available. There are no particular restrictions as long as they achieve the intended effect. Where specific techniques or conditions are not specified in this embodiment, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions.

[0036] In Comparative Example 1 and the embodiments described below, the materials of the transparent substrate, the transparent conductive film layer, the electron transport layer, the perovskite layer, the hole transport layer, and the electrode layer are all existing materials or commercially available materials.

[0037] For example: transparent substrates, including but not limited to glass substrates and flexible PET substrates, wherein the glass used in the glass substrate includes soda-lime glass, aluminosilicate glass, and borosilicate glass;

[0038] Transparent conductive film layer, the materials of which include, but are not limited to, indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), indium-doped zinc oxide (IZO), and fluorine-doped tin oxide (FTO);

[0039] Electron transport layer, the materials of which include, but are not limited to, zinc oxide, titanium dioxide, tin dioxide, PCBM, and nickel oxide.

[0040] The perovskite layer, the materials of which include, but are not limited to, methylamine iodide perovskite (MAPbI3), formamidinium iodide perovskite (FAPbI3), cesium lead iodide (PbCsI3), and methylamine bromide perovskite (MAPbBr3).

[0041] Hole transport layer, the materials of which include, but are not limited to, copper iodide, copper oxide, CuSCN, Spiro-OMETAD, and P3HT.

[0042] Electrode layer, the materials of which include, but are not limited to, gold, silver, aluminum, copper, TCO, and TCO / Ag / TCO.

[0043] Comparative Example 1

[0044] Traditional perovskite solar cell structures, such as Figure 1 , 2 As shown, the perovskite solar cell includes a transparent substrate, which is made of glass. The transparent substrate includes an upper surface and a lower surface.

[0045] Among them, perovskite solar cells with a formal nip structure, such as Figure 1 As shown, a transparent conductive film layer (TCO), an electron transport layer (ETL), a perovskite layer, a hole transport layer (HTL), and a metal electrode layer are arranged sequentially from top to bottom on the lower surface of the transparent substrate 1.

[0046] Pin-type inverted perovskite solar cells, such as Figure 2 As shown, a transparent conductive film layer (TCO), a hole transport layer (HTL), a perovskite layer, an electron transport layer (ETL), and a metal electrode layer are arranged sequentially from top to bottom on the lower surface of the transparent substrate.

[0047] In the aforementioned nip formal structure or pin inverted structure, the transparent conductive film layer uses ITO material with a thickness of 200nm, and the hole transport layer can be made of nickel oxide (NiOx) with a thickness of 20nm; when the solar cell uses... Figure 2 When the pin-reverse structure is used, the average transmittance of sunlight reaching the perovskite layer after passing through the multi-layer interface of the transparent substrate, transparent conductive film (TCO), and hole transport layer (HTL) is 80.2% and 80.7% in the 400-700nm band and the 400-1000nm band, respectively.

[0048] Solar cells generally require a sheet resistance of 5-10Ω for the electrodes and a thickness of 200-500nm for the transparent conductive layer (TCO).

[0049] The electron transport layer (ETL) has a thickness controlled between 0.1 and 50 nm.

[0050] The thickness of the perovskite layer is controlled between 400-2000 nm.

[0051] The thickness of the hole transport layer is controlled at 5-10 nm.

[0052] Example 1

[0053] Perovskite solar cells, such as Figure 3 As shown, the device includes a substrate, on the upper surface of which an antireflective coating is disposed. The antireflective coating can be a single low-refractive-index layer L, or a periodic cycle of a high-refractive-index layer H and a low-refractive-index layer L. One cycle consists of one H layer followed by one L layer (HL), and there can be two cycles (HLHL), three cycles, or even five cycles. The antireflective wavelength can be the visible light band of 400-700 nm, or a wider antireflective wavelength band, such as 400-1000 nm, or even a wider band (400-2000 nm).

[0054] The refractive index of the high-refractive-index material is controlled between 1.8 and 2.8, specifically 2.3; the refractive index of the low-refractive-index material is controlled between 1.3 and 1.7, specifically 1.46. High-refractive-index materials include, but are not limited to, titanium dioxide, niobium pentoxide, tantalum pentoxide, zirconium dioxide, silicon nitride, aluminum nitride, zinc oxide, and ITO; low-refractive-index materials include, but are not limited to, silicon dioxide, aluminum oxide, magnesium fluoride, and calcium fluoride. The antireflective coating has 4-10 layers, and the total thickness of the antireflective coating is 50-800 nm.

[0055] The preparation process of the high refractive index material and the low refractive index material can be vacuum evaporation, magnetron sputtering, atomic layer deposition, chemical vapor deposition, or wet process.

[0056] In this embodiment, the specific AR film structure is as follows: Glass / Nb2O5 11.45nm / SiO2 39.91nm / Nb2O5 43.01nm / SiO2 4.75nm / Nb2O5 64.76nm / SiO2 84.08nm / Air, wherein the group coefficients of silicon oxide and niobium oxide are both 1.

[0057] The other film layers use the same materials and thicknesses as Comparative Example 1. In the solar cell of this embodiment, after sunlight passes through the multilayer interface of the antireflection layer, transparent substrate, transparent conductive film (TCO), and hole transport layer (HTL), the average transmittance reaching the perovskite layer (400-700nm band and 400-1000nm band) is 82.8% and 80.8%, respectively. The average transmittance in the 400-700nm band increases by 2.6%, while the 400-1000nm band does not show a significant increase because the antireflection layer in this embodiment enhances transmittance in the 400-700nm band.

[0058] Example 2

[0059] The perovskite solar cell structure in this embodiment is as follows: Figure 4As shown, it includes a transparent substrate, typically glass or flexible PET. The transparent substrate includes an upper surface and a lower surface. On the lower surface of the substrate, arranged from top to bottom are a transparent conductive (TCO) layer, an index matching layer (IML), a hole transport layer (HTL), a perovskite layer, an electron transport layer (ETL), and a metal electrode layer.

[0060] In perovskite solar cells, the refractive index of the transparent substrate is 1.5, while the refractive indices of other materials are all higher than 1.5. This further increases the reflectivity of light incident on the perovskite layer, thereby reducing the transmittance of light incident on the perovskite layer. Adding an index matching layer (IML) between the glass / TCO / electron transport layer or hole transport layer can reduce this reflection and increase the transmittance of light incident on the perovskite layer. The TCO includes, but is not limited to, indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), indium-doped zinc oxide (IZO), and fluorine-doped tin oxide (FTO).

[0061] The optical matching layer (IML) is made of silicon dioxide, has a thickness of 30 nm, and a refractive index of 1.46.

[0062] The TCO, ETL, HTL, and IML layers can be fabricated using either wet or dry methods, including but not limited to coating, magnetron sputtering, evaporation, chemical vapor deposition, atomic layer deposition, and laser deposition.

[0063] In Example 2, the solar cell used the same materials and thicknesses for the other film layers as in Comparative Example 1. When sunlight passed through the multilayer interface of glass, conductive film (TCO), optical matching film (IML), and hole transport layer (HTL), the average transmittance reaching the perovskite layer (400-700nm band and 400-1000nm band) was 85.7% and 83.5%, respectively.

[0064] Example 3

[0065] The perovskite solar cell structure in this embodiment is as follows: Figure 5 As shown, it includes a transparent substrate, typically glass or flexible PET. The transparent substrate includes an upper surface and a lower surface. On the lower surface of the transparent substrate, from top to bottom, there are arranged a transparent conductive (TCO) layer, an index matching layer (IML), a hole transport layer (HTL), a perovskite layer, an electron transport layer (ETL), and a metal electrode layer. On the upper surface of the transparent substrate 1, there is an anti-reflection thin film layer 7 consistent with that in Example 1; the optical matching layer 7 is consistent with the optical matching layer in Example 2.

[0066] The average transmittance of sunlight reaching the perovskite layer (400-700nm band and 400-1000nm band) after passing through the antireflective coating, glass, transparent conductive film (TCO), optical matching film (IML), and hole transport layer (HTL) is 88.6% and 83.7%, respectively.

[0067] The transmittance of the solar cells in Comparative Example 1 and Examples 1-3 was statistically analyzed, and the results are summarized in Table 1 below:

[0068] Table 1

[0069]

[0070]

[0071] The above embodiments are preferred implementations of the present invention. In addition, the present invention can be implemented in other ways. Any obvious substitutions without departing from the concept of the present invention are within the protection scope of the present invention.

Claims

1. A perovskite solar cell with high photoelectric conversion efficiency, comprising a nip formal structure or a pin inverse structure, The formal structure of NIP includes a transparent substrate, on which a transparent conductive film layer, an electron transport layer, a perovskite layer, a hole transport layer, and an electrode layer are sequentially disposed. The pin inverted structure includes a transparent substrate, on which a transparent conductive film layer, a hole transport layer, a perovskite layer, an electron transport layer, and an electrode layer are sequentially disposed. Its features are, An antireflective coating is disposed on the other side of the transparent substrate; the antireflective coating is composed of alternating stacks of high-refractive-index materials and low-refractive-index materials; the refractive index of the high-refractive-index materials is 1.8-2.8, and the refractive index of the low-refractive-index materials is 1.3-1.7; the high-refractive-index materials include, but are not limited to, titanium dioxide, niobium pentoxide, tantalum pentoxide, zirconium dioxide, silicon nitride, aluminum nitride, zinc oxide, and ITO; the low-refractive-index materials include, but are not limited to, silicon dioxide, aluminum oxide, magnesium fluoride, and calcium fluoride; the antireflective coating has 4-10 layers, and the total thickness of the antireflective coating is 50-800 nm; The battery further includes an optical matching film layer, which is disposed between the transparent conductive film layer and the electron transport layer or between the transparent conductive film layer and the hole transport layer; the refractive index of the optical matching film layer is 1.46; the thickness of the optical matching film layer is 30 nm; and the material of the optical matching film layer is silicon dioxide.

2. The perovskite solar cell with high photoelectric conversion efficiency according to claim 1, characterized in that, The materials of the perovskite layer include, but are not limited to, methylamine iodide perovskite, formamidinium iodide perovskite, cesium lead iodide, and methylamine bromide perovskite.

3. The perovskite solar cell with high photoelectric conversion efficiency according to claim 1, characterized in that, The thickness of the perovskite layer is 400-2000 nm.

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