Hole transport layer material for inverted perovskite solar cell, inverted perovskite solar cell and application

Abstract

The invention relates to a hole transport layer material for an inverted perovskite solar cell, the inverted perovskite solar cell and application, the hole transport layer material is a self-assembled monomolecular layer hole transport material, and the self-assembled monomolecular layer hole transport material comprises an organic compound with the following general formula: # imgabs0 #, r1 and R2 represent independently substituted C6-C15 aryl groups, and the substituent group is a methoxy group or a methylthio group; according to the inverted perovskite cell, holes of the hole transport layer can be reduced, the film forming quality can be improved, and the defects of the lower interface of the perovskite photosensitive layer can be passivated, so that the open-circuit voltage (Voc) and the fill factor (FF) of the inverted perovskite cell are effectively improved, and the photoelectric conversion efficiency of the perovskite cell is effectively improved; and the photoelectric conversion efficiency of the perovskite solar cell is optimal.

Description

Technical Field

[0001] The present invention relates to the technical field of perovskite cells, and in particular to a hole transport layer material for an inverted perovskite solar cell, an inverted perovskite solar cell and applications thereof. Background Art

[0002] The hole transport layer is an important component of inverted perovskite solar cells. It plays a decisive role in hole extraction and transport, surface passivation, perovskite crystallization, device stability and cost. At present, the commonly used hole transport materials are mainly divided into three types: inorganic hole transport materials, organic polymer hole transport materials and organic small molecule hole transport materials. Compared with the first two, organic small molecule hole transport materials have attracted much attention due to their many advantages such as simple synthesis, low cost, easy structure adjustment and small batch difference. However, self-assembled monolayer hole transport materials (SAM) are favored because of their many advantages such as simple synthesis, low cost and easy adjustment of energy levels. However, most self-assembled monolayers are chemically unstable when in contact with perovskites and have a large number of defects, resulting in low photoelectric conversion efficiency of PSCs; and the current success in developing effective SAMs is still limited; therefore, the development and exploration of innovative materials based on SAMs is crucial to unleash their full potential in future perovskite solar cell applications.

[0003] Ultra-thin self-assembled monolayers are considered to be the most promising hole transport layer choice in inverted perovskite solar cells due to their low cost, low material consumption, simple device preparation process, and high efficiency. However, there are still some key deficiencies that need to be addressed in the process of developing the hole transport layer of inverted perovskite solar cells. For example, the hole transport layer film formed by the self-assembled monolayer has holes, resulting in a large number of defects at the interface between the perovskite light absorption layer and the transport layer, thereby increasing the non-radiative recombination of carriers at the interface, and then reducing the open circuit voltage and fill factor of the device, ultimately resulting in low photoelectric conversion efficiency of perovskite solar cells. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, the present invention provides a hole transport layer material for inverted perovskite solar cells, an inverted perovskite solar cell and its application, which can effectively reduce the defect state density of perovskite solar cells, inhibit non-radiative recombination, reduce ion migration and hysteresis, and construct a gradient-arranged energy level between the perovskite layer and the electrode layer, reduce the energy level barrier, and thus make hole transfer more efficient.

[0005] To achieve the above object, the technical solution adopted by the present invention is a hole transport layer material for an inverted perovskite solar cell, and the hole transport layer material is a self-assembled monolayer hole transport material, and the self-assembled monolayer hole transport material includes an organic compound with the following general formula:

[0006]

[0007] Wherein: L represents a C1-C6 alkylene group; R1 and R2 represent independently substituted C6-C15 aryl groups, and the substituents are methoxy or methylthio.

[0008] Preferably, the chemical formula of the organic compound includes at least one or more of the following:

[0009]

[0010]

[0011]

[0012] Preferably, the organic compound

[0013] The synthesis method includes:

[0014] Step 1:

[0015]

[0016] Among them, the reaction condition is to react for 24 h at room temperature; Step 2:

[0017]

[0018] Among them, the reaction condition is to reflux for 18 h by heating;

[0019] Step 3:

[0020]

[0021] Among them, the reaction condition is to react for 24 h at 25 °C.

[0022] Preferably, in Step 1, after the reaction is completed, dichloromethane is used for extraction to obtain an organic phase, the organic phase is dried with anhydrous sodium sulfate, the solvent is removed by distillation under reduced pressure to obtain a crude product; the crude product is separated by a chromatographic column, and petroleum ether / ethyl acetate is used as an eluent to obtain the product after the reaction in Step 1.

[0023] An inverted perovskite solar cell includes a hole transport layer prepared from the hole transport layer material for an inverted perovskite solar cell according to any one of the above.

[0024] Preferably, it further includes a conductive substrate, a perovskite light-absorbing layer, an electron transport layer, and a metal electrode. The hole transport layer is located between the conductive substrate and the perovskite light-absorbing layer. The material of the perovskite light-absorbing layer includes the following components: PbI2, MABr, PbBr2, FAI, CsI, PbCl; the mass ratio of PbI2, MABr, PbBr2, FAI, CsI, PbCl is: 1.1:1:0.2:0.2.

[0025] Preferably, the thickness of the hole transport layer is 5 - 50 nm. The solution of the hole transport layer material with a concentration of 0.5 - 1.0 mol / L prepared is spin-coated on the surface of the conductive substrate at a speed of 1000 - 5000 rpm and annealed at 100 °C for 10 minutes to obtain the hole transport layer.

[0026] Preferably, the electron transport layer is composed of C 60 and BCP, and their thicknesses are 80 nm - 150 nm respectively. The electron transport layer is deposited on the perovskite light-absorbing layer by vacuum evaporation. When performing the evaporation, the evaporation vacuum degree is 5×10 -4 Pa, and the evaporation rate is 0.2 Å / s.

[0027] An application of the hole transport layer material in a photovoltaic device, a photodetector, or a light-emitting diode.

[0028] The specific beneficial effects of the present invention are:

[0029] By using the novel hole transport material provided by the present invention as the hole transport layer, the holes in the hole transport layer can be reduced, the film-forming quality can be improved, and the defects at the lower interface of the perovskite photosensitive layer can be passivated. Therefore, the open-circuit voltage (Voc) and fill factor (FF) of the inverted perovskite battery are effectively improved, so that the photoelectric conversion efficiency of the perovskite battery is effectively enhanced, and the photoelectric conversion efficiency of the perovskite solar cell reaches the optimum. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention and their design schemes, the accompanying drawings required for the present embodiments will be briefly introduced below. The accompanying drawings in the following description are only partial embodiments of the present invention. For those of ordinary skill in the art, other accompanying drawings can be obtained based on these drawings without creative efforts.

[0031] Figure 1 It is the J-V curve of the hole transport layer prepared from the organic compound 27 at different concentrations in the embodiments of the present invention.

[0032] Figure 2 It is the structural schematic diagram of the inverted perovskite solar cell in the embodiments of the present invention. Detailed Implementation Modes

[0033] To make the objectives, technical solutions, and advantages of the present invention clearer, the following will further describe in detail the embodiments of the present application in conjunction with the accompanying drawings.

[0034] When the following description relates to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0035] This embodiment provides a hole transport layer material for an inverted perovskite solar cell. The hole transport layer material is a self-assembled monolayer hole transport material, and the self-assembled monolayer hole transport material includes an organic compound with the following general formula:

[0036]

[0037] Wherein: L represents a C1-C6 alkylene group; R1 and R2 represent independently substituted C6-C15 aryl groups, and the substituents are or methoxy or methylthio.

[0038] This embodiment provides the following specific organic compounds formed from the above general formula. The chemical formulas of the specific organic compounds are shown as follows:

[0039]

[0040]

[0041]

[0042] To understand the specific synthesis method of the above compounds, this embodiment uses the specific synthesis method of compound 27 to illustrate the synthesis method of the above compounds.

[0043] Step 1: Synthesis of Intermediate 27-1

[0044] The specific synthesis formula of compound 27-1 is:

[0045]

[0046] The specific synthesis method is as follows: Dissolve 1,4-dibromobutane (0.9 mL) and NaH (0.15 g) in a flask containing 20 mL of DMF. Dissolve 5-phenyl-5,8-dihydroindolo[2,3-c]carbazole (0.83 g, 2.51 mmol) in DMF (3 mL) and slowly add it using a syringe. React at room temperature for 24 h; after the reaction, extract with dichloromethane to obtain the organic phase, dry the organic phase with anhydrous sodium sulfate, distill off the solvent under reduced pressure to obtain the crude product. Separate the crude product using a chromatography column with petroleum ether / ethyl acetate as the eluent (volume ratio 10:1) to obtain intermediate 27-1 (0.93 g, yield 82%).

[0047] Step 2: Synthesis of intermediate 27-2

[0048] The specific synthesis formula of compound 27-2 is as follows:

[0049]

[0050] The specific synthesis method is as follows: Dissolve the intermediate 27-1 (0.89 g, 2.0 mmol) synthesized in Step 1 in triethyl phosphite (6 mL) and reflux the reaction solution for 18 h. After the reaction is completed, distill off the solvent under reduced pressure to obtain the crude product. Separate the crude product using a chromatography column with petroleum ether / ethyl acetate as the eluent (volume ratio 1:6) to obtain intermediate 27-2 (0.84 g, yield 78%).

[0051] Step 3: Synthesis of compound 27

[0052] The specific synthesis formula of compound 27 is as follows:

[0053]

[0054] The specific synthesis method is as follows:

[0055] Add the intermediate 27-2 (0.76 g, 1.5 mmol) synthesized in Step 2 and 1,4-dioxane (15 mL) to a three-necked flask, dropwise add trimethylsilyl bromide (1.72 mL) under nitrogen protection, and react at 25 °C for 24 h; after the reaction, distill off the solvent under reduced pressure, then dissolve in methanol (10 mL), dropwise add deionized water (15 mL) until the solution becomes turbid, continue stirring for 15 h, filter out the solid, wash with deionized water, and dry to obtain 0.58 g of product 27 (yield 85%).

[0056] This example provides a method for preparing a hole transport layer using the synthesized compound 27 and using this hole transport layer as an inverted perovskite solar cell. The structure of this inverted perovskite solar cell is as Figure 2As shown, it includes a conductive substrate, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, and a metal electrode, which are arranged from bottom to top.

[0057] Example 1

[0058] This example provides a method for preparing an inverted perovskite solar cell using a compound 27 as a hole transport layer material, which includes:

[0059] Preparation of the conductive substrate: The conductive substrate is cleaned with a glass cleaner, deionized water, and an ethanol solution respectively, and then dried in a forced-air drying oven at 100 °C. After that, it is subjected to ultraviolet ozone treatment for 30 minutes to obtain the conductive substrate;

[0060] Preparation of the hole transport layer: The prepared compound 27 is mixed with absolute ethanol to obtain a hole transport layer solution. Among them, the concentration of the hole transport layer solution is 0.5 mol / L. The treated conductive substrate is transferred to a spin coater for standby. Then, the treated hole transport layer solution is spin-coated at a speed of 1000 - 5000 rpm for 10 - 50 s, and then placed on a hot plate at 100 °C for annealing for 10 minutes to complete the coating of the hole transport layer on the conductive substrate;

[0061] Preparation of the perovskite light-absorbing layer: PbI2, MABr, PbBr2, FAI, CsI, and PbCl are dissolved in a mixed solution of DMF:DMSO = 4:1 in a certain proportion to prepare a perovskite precursor solution with a concentration of 1.5 mol / L. Among them, the mass ratio of PbI2, MABr, PbBr2, FAI, CsI, and PbCl is: 1.1:1:0.2:0.2;

[0062] After that, the above-assembled hole transport layer substrate is subjected to ozone treatment or plasma treatment for 10 - 30 minutes, and then transferred to a spin coater. A certain amount of perovskite precursor solution is dropped onto the surface of the prepared hole transport layer. After standing, it is spin-coated at a speed of 500 - 8000 rpm for 10 - 80 s, and a certain amount of chlorobenzene antisolvent is dropped 10 - 25 s before the end of spin coating; after the spin coating is completed, the substrate is quickly placed on a hot stage at 100 - 300 °C for annealing for 20 - 60 minutes to form a perovskite light-absorbing layer on the hole transport layer;

[0063] Preparation of the electron transport layer: The materials required for the electron transport layer in this example are C 60 and BCP, and the thickness of this electron transport layer is 80 - 150 nm in sequence. When preparing, the required materials are evaporated onto the prepared perovskite light-absorbing layer by evaporation to form an electron transport layer. When evaporating, the evaporation conditions are: in an environment with a vacuum degree of 5 * 10 -4 Pa, and the evaporation rate is 0.2 Å / s.

[0064] Preparation of the metal electrode. In this embodiment, the selected metal electrode material is silver, and the thickness of the metal electrode is 1200 nm. When fabricating the metal electrode, the required silver is evaporated onto the prepared electron transport layer by evaporation. Among them, the vacuum degree of the evaporation chamber is 5*10 -4 Pa, and the evaporation rate is 2 Å / s.

[0065] Example 2

[0066] Based on Example 1, when preparing the hole transport layer, the concentration of the hole transport layer solution coated is 0.7 mol / L.

[0067] Example 3

[0068] Based on Example 1, when preparing the hole transport layer, the concentration of the hole transport layer solution coated is 1 mol / L.

[0069] Comparative Example 1

[0070] This comparative example provides an inverted perovskite solar cell, which includes a conductive substrate, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, and a metal electrode. Among them, the materials selected for the conductive substrate, the perovskite light-absorbing layer, the electron transport layer, and the metal electrode are exactly the same as the materials and preparation methods required for the conductive substrate, the perovskite light-absorbing layer, the electron transport layer, and the metal electrode in the examples. The material of the hole transport layer in this Comparative Example 1 is prepared from a conventional compound Me-4PACz.

[0071] The following is a test on the optoelectronic properties of the cells 1, 2, 3 prepared in Example 1, Example 2, Example 3 and Comparative Example 1 and the comparative cell. The test method is as follows: when conducting the test, a solar simulation test system is used for measurement. The light source part uses a 500 W xenon lamp solar spectrum simulator, and a standard silicon cell is used to calibrate the light source. The measurement is carried out under a sunlight intensity (AM1.5G: 100 mW / cm 2 ). A continuously varying voltage (-0.1 V - 1.2 V) within a certain range is applied to both ends of cells 1, 2, 3 and the comparative cell respectively, and then the output current of the cell is measured (the test power supply uses Keithley2450). Finally, the product of the two can obtain the Figure 1 shown J-V test curve, showing the optoelectronic conversion efficiency of the device in different states.

[0072] At the same time, the photovoltaic performance of cells 1, 2, 3 and the comparative cell is tested, and the test results are shown in the following table:

[0073]

[0074] As can be seen from the table, by using the novel hole transport layer material provided by the present invention as the hole transport layer, the holes in the hole transport layer are reduced, the film forming quality is improved, and the defects at the lower interface of the perovskite photosensitive layer can be passivated. Therefore, the open circuit voltage (Voc) and fill factor (FF) of the inverted perovskite solar cell are effectively improved, thereby greatly enhancing the photoelectric conversion efficiency of the perovskite solar cell. Especially when the concentration of the new material is 0.5 mol / L, the photoelectric conversion efficiency of the perovskite solar cell reaches the optimum.

[0075] This embodiment also provides an application of the prepared hole transport material in a photovoltaic device, a photodetector or a light emitting diode.

[0076] In addition, any combination can be made among various different embodiments of the present disclosure as long as it does not violate the idea of the present disclosure, and it should also be regarded as the content disclosed by the present disclosure.

Claims

1. A hole transport layer material for an inverted perovskite solar cell, characterized in that, The hole transport layer material is a self-assembled monolayer hole transport material, and the self-assembled monolayer hole transport material includes an organic compound with the following general formula: Wherein: L represents a C1-C6 alkylene group; R1 and R2 represent independently substituted C6-C15 aryl groups, and the substituents are methoxy or methylthio groups.

2. The hole transport layer material for an inverted perovskite solar cell according to claim 1, wherein The chemical formula of the organic compound includes at least one or more of the following:

3. The hole transport layer material for an inverted perovskite solar cell according to claim 2, wherein The organic compound The synthesis method includes: Step 1: Wherein, the reaction condition is to react for 24 h at room temperature; Step 2: Wherein, the reaction condition is to reflux under heating for 18 h; Step 3: Wherein, the reaction condition is to react for 24 h at 25 °C.

4. The hole transport layer material for an inverted perovskite solar cell according to claim 3, characterized in that, In Step 1, after the reaction is completed, dichloromethane is used for extraction to obtain an organic phase, and the organic phase is dried with anhydrous sodium sulfate, and the solvent is removed by distillation under reduced pressure to obtain a crude product; the crude product is separated by a chromatographic column with petroleum ether / ethyl acetate as the eluent to obtain the product after the reaction in Step 1.

5. An inverted perovskite solar cell, characterized in that, It includes a hole transport layer prepared from the hole transport layer material for an inverted perovskite solar cell according to any one of claims 1-4.

6. The inverted perovskite solar cell according to claim 5, characterized in that, It further includes a conductive substrate, a perovskite light-absorbing layer, an electron transport layer and a metal electrode. The hole transport layer is located between the conductive substrate and the perovskite light-absorbing layer. The material of the perovskite light-absorbing layer includes the following components: PbI2, MABr, PbBr2, FAI, CsI, PbCl; the mass ratio of PbI2, MABr, PbBr2, FAI, CsI, PbCl is: 1.1:1:0.2:0.

2.

7. The inverted perovskite solar cell according to claim 5, characterized in that, The thickness of the hole transport layer is 5-50 nm. The prepared hole transport layer material solution with a concentration of 0.5-1.0 mol / L is coated on the surface of the conductive substrate by spin coating at a speed of 1000-5000 rpm, and annealed at 100 °C for 10 minutes to obtain the hole transport layer.

8. The inverted perovskite solar cell according to claim 5, wherein, The electron transport layer consists of C 60 and BCP, with thicknesses of 80 nm - 150 nm respectively. The electron transport layer is deposited onto the perovskite light-absorbing layer by vacuum evaporation. When performing the evaporation, the evaporation vacuum is 5×10 -4 Pa, and the evaporation rate is 0.2 Å / s.

9. The application of the hole transport layer material according to any one of claims 1-4 in a photovoltaic device, a photodetector or a light-emitting diode.

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