Ferrocene compound-based hole transport material, perovskite solar cell containing hole transport material and application of hole transport material in perovskite photoelectric device

Abstract

The invention provides a hole transport material based on a ferrocene compound, a perovskite solar cell containing the hole transport material and application of the hole transport material in a perovskite photoelectric device. The hole transport material is simple in structure and low in cost; the material can be applied to a perovskite photoelectric device and has good photoelectric conversion efficiency; and the structure expansibility is good.

Description

TECHNICAL FIELD The present application relates to a ferrocene-based hole transport material, belonging to the field of solar cells. BACKGROUND As a representative of the new generation of thin film solar cells, the photoelectric conversion efficiency of perovskite solar cells has been comparable to that of crystalline silicon cells, and has the advantages of low cost, solution processing, etc., which can meet the application requirements of different scenes. The transverse structure of perovskite solar cells (basic structure includes transparent conductive substrate / hole transport layer / perovskite layer / electron transport layer / back electrode) has gradually become the focus of research in recent years due to its excellent stability. Among the many hole transport materials used in the hole transport layer, self-adsorbed hole transport materials undergo chemical reactions between the anchor group and the transparent conductive substrate, have the advantages of strong light transmittance, low material consumption, and low roughness. The self-adsorbed hole transport materials reported in the literature are mostly based on carbazole and its derivatives as the molecular skeleton, with different anchor groups bridged. Although perovskite solar cells prepared from self-adsorbed hole transport materials based on carbazole and its derivatives exhibit high photoelectric conversion efficiency, however, the synthesis of carbazole-based self-adsorbed materials has the disadvantages of expensive raw materials, multiple synthesis steps, and difficult separation and purification, which limits its large-scale commercial application. In addition, the hydrophobicity of the carbazole skeleton also brings additional difficulties to the preparation of the perovskite layer. Therefore, developing a new type of self-adsorbed hole transport material to realize the low-cost and high-efficiency preparation of perovskite solar cells has important practical significance for accelerating the commercial application of perovskite solar cells. SUMMARY Problems to be solved by the invention The present application aims to seek a self-adsorbed hole transport material that can replace the carbazole and its derivatives of the prior art, and apply it to transverse structure perovskite solar cells and other perovskite optoelectronic devices, so that the perovskite solar cells and other perovskite optoelectronic devices have high photoelectric conversion efficiency and long-term working stability. Solution to the problem

[0001] A ferrocene-based hole transport material, wherein the hole transport material comprises a ferrocene compound having the following structure, wherein R1 is one of formic acid group, acetic acid group, propionic acid group, phosphoric acid group, boric acid group, and silicic acid group; R2 is one of hydrogen atom, formic acid group, acetic acid group, propionic acid group, phosphoric acid group, boric acid group, and silicic acid group.

[0002] The hole transport material according to [1], wherein R1 and R2 are both formic acid groups.

[0003] According to the hole transport material described in [1], R1 is a formic acid group; R2 is a hydrogen atom.

[0004] According to the hole transport material described in [1], R1 and R2 are both borate-based.

[0005] According to the hole transport material described in [1], R1 is an acetic acid group; R2 is a hydrogen atom.

[0006] A perovskite solar cell includes a transparent conductive substrate, a hole transport layer, a perovskite layer, an electron transport layer and a back electrode arranged sequentially; the hole transport layer contains a hole transport material according to any one of [1]-[5].

[0007] Application of hole transport materials according to any one of [1]-[5] in perovskite optoelectronic devices. The effects of the invention (1) The hole transport material based on ferrocene compounds described in this invention has a simple structure and low cost; (2) The hole transport material based on ferrocene compounds described in this invention can be applied to perovskite optoelectronic devices and has good photoelectric conversion efficiency; (3) The hole transport material based on ferrocene compounds described in this invention has good structural scalability. Attached Figure Description Figure 1 This is a structural diagram of the perovskite solar cell of the present invention. Figure 2 The JV curve is shown for a perovskite solar cell using the hole transport material of the present invention. Figure 3 Cyclic voltammetry curves for different hole transport materials. Figure 4 This is an energy level matching diagram between the hole transport material of the present invention and perovskite. Detailed Implementation Various exemplary embodiments, features, and aspects of the present invention will be described in detail below. The term "exemplary" as used herein means "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as superior to or better than other embodiments. Furthermore, to better illustrate the present invention, numerous specific details are set forth in the following detailed embodiments. Those skilled in the art should understand that the present invention can be practiced without certain specific details. In other instances, methods, means, apparatus, and steps well known to those skilled in the art have not been described in detail in order to highlight the spirit of the present invention. The units used in the present specification are international standard units, and the numerical values and numerical value ranges appearing in the present application should be understood as including systematic errors that are inevitable in industrial production, unless otherwise specified. One aspect of the present application provides a ferrocene-based compound-based hole transport material, wherein the hole transport material comprises a ferrocene-based compound having the following structure, wherein R1 is one of formic acid group, acetic acid group, propionic acid group, phosphoric acid group, boric acid group, and silicic acid group; and R2 is one of hydrogen atom, formic acid group, acetic acid group, propionic acid group, phosphoric acid group, boric acid group, and silicic acid group. Preferably, R1 and R2 are both formic acid groups; or R1 is formic acid group and R2 is hydrogen atom; or R1 and R2 are both boric acid groups; or R1 is acetic acid group and R2 is hydrogen atom. The ferrocene-based compound used in the present application can be prepared by conventional methods or purchased commercially. The advantage of the present application over the prior art is that the ferrocene-based compound is included in the hole transport material, thereby improving the photoelectric conversion efficiency of perovskite solar cells and other perovskite optoelectronic devices using the hole transport material, and making them work stably for a long time. Another aspect of the present application provides a perovskite solar cell comprising, in order, a transparent conductive substrate, a hole transport layer, a perovskite layer, an electron transport layer, and a back electrode; the hole transport layer comprising the hole transport material according to the present application. As Figure 1 The perovskite solar cell of the present application can further comprise another substrate, such as a glass substrate, adjacent to the transparent conductive substrate, as shown. In the present application, the transparent conductive substrate, perovskite layer, electron transport layer, and back electrode can be made of conventional materials. Still another aspect of the present application provides the use of the hole transport material according to the present application in a perovskite optoelectronic device, which can improve the photoelectric conversion efficiency of the perovskite optoelectronic device. Examples The embodiments of the present application will be described in detail below with reference to examples, but those skilled in the art will understand that the following examples are only for illustration of the present application and should not be considered as limiting the scope of the present application. If no specific conditions are specified in the examples, the conventional conditions or the conditions recommended by the manufacturer are used. If no manufacturer of the reagent or instrument is specified, it is a conventional product that can be obtained commercially. Example 1 1,1'-ferrocene dicarboxylic acid was used as a hole transport material, which was used as a hole transport layer in a perovskite solar cell, and the photovoltaic parameters of the cell were tested. The battery adopts a reverse p-i-n structure, as shown in Figure 1 which includes a glass substrate, a transparent conductive substrate, a hole transport layer, a perovskite layer, an electron transport layer, and a back electrode. The preparation process of the battery is as follows: (1) The transparent conductive substrate (fluorine-doped tin oxide FTO) was ultrasonically cleaned with glass cleaner, ultrapure water, anhydrous ethanol, and isopropanol for 20 minutes, and then the surface residual solvent was blown dry with nitrogen. The transparent conductive substrate was treated with ultraviolet ozone to remove the residual organic matter on the surface. Then the transparent conductive substrate was laminated on the glass substrate. (2) The hole transport layer was prepared on the transparent conductive substrate by spin coating an ethanol solution of 1,1'-ferrocene dicarboxylic acid at a spin speed of 3000 rpm for 30 seconds, and then heated at 100°C for 10 minutes after spin coating. (3) The perovskite layer was deposited on the hole transport layer. The components of the perovskite were Cs 0.10 MA 0.05 FA 0.80 PbI3. Specifically, first spin-coat the perovskite precursor solution on the hole transport layer, drop a certain amount of chlorobenzene as an anti-solvent during the spin-coating process, and finally obtain the perovskite film after heating at 100°C for 20 minutes. Then the electron transport layer was prepared on the perovskite layer by vacuum sequential evaporation of C 60 and BCP (bathocuproin) with thicknesses of 25 nm and 6 nm, respectively. Finally, a silver electrode with a thickness of 60-100 nm was evaporated on the electron transport layer. Example 2 Ferrocene dicarboxylic acid was used as a hole transport material, which was used as a hole transport layer for perovskite solar cells, and the photovoltaic parameters of the battery were tested. The battery adopts a reverse p-i-n structure, as shown in Figure 1 which includes a glass substrate, a transparent conductive substrate, a hole transport layer, a perovskite layer, an electron transport layer, and a back electrode. The preparation process of the battery is as follows: (1) The transparent conductive substrate (fluorine-doped tin oxide FTO) was ultrasonically cleaned with glass cleaner, ultrapure water, anhydrous ethanol, and isopropanol for 20 minutes, and then the surface residual solvent was blown dry with nitrogen. The transparent conductive substrate was treated with ultraviolet ozone to remove the residual organic matter on the surface. Then the transparent conductive substrate was laminated on the glass substrate. (2) The hole transport layer was prepared on the transparent conductive substrate by spin coating an ethanol solution of ferrocene dicarboxylic acid at a spin speed of 3000 rpm for 30 seconds, and then heated at 100°C for 10 minutes after spin coating. (3) The perovskite layer was deposited on the hole transport layer. The components of the perovskite were Cs0.10 MA 0.05 FA 0.80 PbI3. Specifically, first spin-coat perovskite precursor solution on the hole transport layer, drop a certain amount of isopropanol as anti-solvent during the spin-coating process, and finally heat at 100 degrees Celsius for 20 minutes to obtain perovskite thin film. Then, electron transport layer is prepared by vacuum sequential evaporation of C 60 and BCP (bathocuproin) method, which are deposited at a thickness of 25 nanometers and 6 nanometers, respectively. Finally, silver electrode with a thickness of 60-100 nanometers is evaporated on the electron transport layer. Example 3 1,1'-ferrocene diboronic acid is used as a hole transport material, which is used as a hole transport layer for perovskite solar cells, and the photovoltaic parameters of the cells are tested. The cell adopts a trans-p-i-n structure, as shown in Figure 1 , which includes a glass substrate, a transparent conductive substrate, a hole transport layer, a perovskite layer, an electron transport layer, and a back electrode. The preparation process of the cell is as follows: (1) The transparent conductive substrate (indium-doped tin oxide ITO) is ultrasonically cleaned with glass cleaner, ultrapure water, anhydrous ethanol, and isopropanol in sequence for 20 minutes, and then the surface residual solvent is blown dry with nitrogen. The transparent conductive substrate is treated with ultraviolet ozone to remove the residual organic matter on the surface. Then the transparent conductive substrate is laminated on the glass substrate. (2) The hole transport layer is prepared by spin-coating 1,1'-ferrocene diboronic acid ethanol solution on the transparent conductive substrate at a spin-coating speed of 3000 rpm, a spin-coating time of 30 seconds, and heating at 100 degrees Celsius for 10 minutes after spin-coating. (3) The perovskite layer is deposited on the hole transport layer. The composition of the perovskite is Cs 0.10 MA 0.05 FA 0.80 PbI3. Specifically, first spin-coat perovskite precursor solution on the hole transport layer, drop a certain amount of isopropanol as anti-solvent during the spin-coating process, and finally heat at 100 degrees Celsius for 20 minutes to obtain perovskite thin film. Then, electron transport layer is prepared by vacuum sequential evaporation of C 60 and BCP (bathocuproin) method, which are deposited at a thickness of 25 nanometers and 6 nanometers, respectively. Finally, silver electrode with a thickness of 60-100 nanometers is evaporated on the electron transport layer. Example 4 Ferrocene acetic acid is used as a hole transport material, which is used as a hole transport layer for perovskite solar cells, and the photovoltaic parameters of the cells are tested. The cell adopts a trans-p-i-n structure, as shown in Figure 1As shown, it comprises a glass substrate, a transparent conductive substrate, a hole transport layer, a perovskite layer, an electron transport layer and a back electrode. The preparation process of the battery is as follows: (1) The transparent conductive substrate (indium-doped tin oxide ITO) was ultrasonically cleaned with glass cleaner, ultrapure water, anhydrous ethanol and isopropanol in sequence for 20 minutes, and then the surface residual solvent was blown dry with nitrogen. The transparent conductive substrate was treated with ultraviolet ozone to remove the surface residual organic matter. Then the transparent conductive substrate was laminated on the glass substrate. (2) The hole transport layer was prepared on the transparent conductive substrate by spin coating an ethanol solution of ferrocene acetic acid at a spin speed of 3000 rpm for 30 seconds, and then heated at 100 degrees Celsius for 10 minutes. (3) The perovskite layer was deposited on the hole transport layer. The components of the perovskite were Cs 0.10 MA 0.05 FA 0.80 PbI3. Specifically, first spin-coat the perovskite precursor solution on the hole transport layer, drop a certain amount of chlorobenzene as an anti-solvent during the spin-coating process, and finally obtain the perovskite film after heating at 100 degrees Celsius for 20 minutes. Then the electron transport layer was prepared on the perovskite layer by vacuum sequential evaporation of C 60 and BCP (bathocuproine), which were deposited to a thickness of 25 nanometers and 6 nanometers, respectively. Finally, a silver electrode with a thickness of 60-100 nanometers was evaporated on the electron transport layer. The following Table 1 shows the photovoltaic parameters of the batteries using different hole transport materials in Examples 1-4. Table 1 It can be seen that the hole transport material of the present application can improve the photoelectric conversion efficiency of the perovskite solar cell, and in particular the photoelectric conversion efficiency of the perovskite solar cell using 1,1-ferrocene dicarboxylic acid can reach more than 20%. And the performance of the perovskite solar cell using the above four kinds of hole transport materials is close, indicating that the ferrocene compound of the present application as a hole transport material has good universality. Figure 2 The J-V curve of the perovskite solar cell using the hole transport material of the present application is shown in the following figure, from which it can be seen that the perovskite solar cells using different ferrocene self-adsorbed hole transport materials show similar device parameters, indicating that this kind of material has good universality and better hole transport performance. Figure 3The cyclic voltammograms of different hole transport materials can be seen from which the different ferrocene self-adsorbed hole transport materials and the different substituents and the number of substituents have influence on the initial oxidation potential of the materials, and the highest occupied orbital energy level position of different hole transport materials can be obtained by comparison with the initial oxidation potential of the internal standard Fc / Fc+. Figure 4 The energy level matching diagram of the hole transport material of the present application and the perovskite can be seen from which the highest occupied orbital energy level position (HOMO) of different ferrocene self-adsorbed hole transport materials is higher than the HOMO energy level of the perovskite, which is beneficial to the transmission of free holes between the perovskite and the hole transport material. It should be noted that although the technical solutions of the present application are introduced with specific examples, those skilled in the art can understand that the present application should not be limited thereto. The above has described various embodiments of the present application, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those skilled in the art without departing from the scope and spirit of the described embodiments. The choice of terms used herein is intended to best explain the principles of the embodiments, practical application or improvement of technology in the market, or to enable other ordinary skilled persons in the art to understand the embodiments disclosed herein.

Claims

1. A hole transport material based on ferrocene compounds, characterized in that, The hole transport material comprises ferrocene compounds with the following structure. Wherein R1 is one of formic acid group, acetate group, propionic acid group, phosphoric acid group, boric acid group, and silicate group; R2 is one of hydrogen atom, formic acid group, acetate group, propionic acid group, phosphoric acid group, boric acid group, and silicate group.

2. The hole transport material according to claim 1, characterized in that, Both R1 and R2 are formic acid groups.

3. The hole transport material according to claim 1, characterized in that, R1 is a formic acid group; R2 is a hydrogen atom.

4. The hole transport material according to claim 1, characterized in that, Both R1 and R2 are borate groups.

5. The hole transport material according to claim 1, characterized in that, R1 is an acetate group; R2 is a hydrogen atom.

6. A perovskite solar cell, characterized in that, It comprises a transparent conductive substrate, a hole transport layer, a perovskite layer, an electron transport layer, and a back electrode arranged sequentially; the hole transport layer comprises a hole transport material according to any one of claims 1-5.

7. The application of the hole transport material according to any one of claims 1-5 in perovskite optoelectronic devices.

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