Hole transport material and preparation method thereof and perovskite solar cell

Abstract

The present invention discloses a hole transport material, a preparation method thereof, and a perovskite solar cell, wherein the hole transport material comprises a phenanthroline metal complex as shown in Formula 1: M is a divalent metal ion; X is a halogen ion. The phenanthroline metal complex of the present invention has excellent semiconductor properties; and its physical, electronic, and optical properties can be regulated by changing the divalent metal element therein; in particular, the halogen ions contained in the phenanthroline metal complex can react with the Pb that is not fully coordinated on the surface of the perovskite light-absorbing layer. 2+ Ionic bonding has an interface passivation effect, reducing the ineffective loss of carriers, thereby effectively improving the device stability and service life of the solar cell; in addition, the o-phenanthroline metal complex shown in Formula 1 is easy to obtain and low in cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of solar cells, and in particular relates to a hole transport material and a preparation method thereof, and a perovskite solar cell. Background Art

[0002] Over the past decade, organic-inorganic hybrid perovskite solar cells have attracted widespread attention from the global research and industry communities due to their exceptional photoelectric conversion efficiency and affordability. Although this technology's photoelectric conversion efficiency has reached commercial standards and is gradually moving towards industrialization, its relatively short lifespan and poor stability remain major obstacles to its large-scale commercialization.

[0003] Perovskite solar cells include a substrate layer, an electron transport layer, a perovskite light-absorbing layer, a hole transport layer, and an electrode layer. The hole transport layer can optimize the interface, improve the extraction and transport efficiency of hole carriers, and protect the perovskite active layer, which has a crucial impact on the performance and life of the device. Currently reported high-efficiency perovskite solar cells mostly use organic small molecule materials to prepare the hole transport layer, a typical representative of which is spirofluorene-type organic small molecules, such as 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD), etc. However, such materials are expensive, which limits their practical promotion. In addition, such materials often need to be doped with lithium salts such as lithium bis(trifluoromethanesulfonyl imide) (LiTFSI) to enhance their conductivity, and the hygroscopicity of lithium salts and Li + The diffusion of organic small molecules will have a negative impact on the device life and stability. Therefore, cost and instability have become the two main factors hindering the widespread application of such organic small molecule materials in the field of perovskite solar cells.

[0004] Therefore, there is an urgent need for a hole transport material and a preparation method thereof and a perovskite solar cell to solve the deficiencies of the existing technical problems. Summary of the Invention

[0005] In view of the above problems, the object of the present invention is to provide a hole transport material, a preparation method thereof, and a perovskite solar cell, wherein the hole transport material can improve the energy conversion efficiency, stability and service life of the perovskite solar cell.

[0006] To achieve the above objectives, the first aspect of the present invention provides a hole transport material comprising a phenanthroline metal complex as shown in Formula 1:

[0007]

[0008] M is a divalent metal ion; X is a halogen ion.

[0009] Compared with the prior art, the o-phenanthroline metal complex shown in Formula 1 of the present invention has excellent semiconductor properties, which can efficiently participate in the charge transfer process, thereby significantly improving the energy conversion efficiency of solar cells. In addition, the physical, electronic and optical properties thereof can be regulated by changing the divalent metal elements therein to adapt to different working environments and application requirements. In particular, the halogen ions contained in the o-phenanthroline metal complex can react with the Pb that is not fully coordinated on the surface of the perovskite light-absorbing layer. 2+ Ionic binding has an interface passivation effect, reducing the ineffective loss of carriers, thereby effectively improving the device stability and service life of solar cells; in addition, the o-phenanthroline metal complex shown in Formula 1 is easy to obtain and low in cost, providing a basis for large-scale production applications.

[0010] Furthermore, M of the present invention is Cu 2+ 、Zn 2+ 、Co 2+ 、Ni 2+ 、Fe 2+ 、Mn 2+ , Pb 2+ , Pt 2+ or Pd 2+ , X is F - 、Cl - Br - or I - .

[0011] Accordingly, the second aspect of the present invention further provides a method for preparing a hole transport material, comprising the following steps:

[0012] (1) mixing a TPA-containing o-phenanthroline ligand shown in Formula 2, a divalent metal halide, and an organic solvent and reacting the mixture;

[0013] (2) post-treating the reaction product obtained in step (1);

[0014]

[0015] Compared with the prior art, the present invention obtains a hole transport material by directly reacting a mixture of a 1,2-diphenylamine (TPA) group-containing o-phenanthroline ligand, a divalent metal halide, and an organic solvent. Therefore, the preparation method provided by the present invention has simple preparation steps, is easy to industrialize, and uses low-cost raw materials.

[0016] Furthermore, in step (1) of the present invention, the molar ratio of the o-phenanthroline ligand containing a TPA group to the divalent metal halide is 1 to 5:1.

[0017] Furthermore, the reaction conditions in step (1) of the present invention are: reaction at room temperature to 100° C. for 2 to 24 hours.

[0018] Furthermore, the divalent metal halide in step (1) of the present invention includes CuX2, ZnX2, CoX2, NiX2, FeX2, MnX2, PbX2, PtX2 or PdX2, wherein X is F, Cl, Br or I.

[0019] Furthermore, the preparation of the TPA-group-containing o-phenanthroline ligand represented by Formula 2 of the present invention comprises: reacting 4-boronate-4',4'-dimethoxytriphenylamine, 3,8-dibromo-1,10-phenanthroline, tetrakis(triphenylphosphine)palladium and potassium carbonate in a molar ratio of 2-3:1:0.1-0.15:20-50 in a solvent to obtain the obtained product.

[0020] Furthermore, the solvent of the present invention is composed of N,N-dimethylformamide (DMF) and water in a volume ratio of 1:1-2, and the concentration of potassium carbonate in the solvent is 0.3-1M.

[0021] Furthermore, the post-treatment in step (2) of the present invention includes filtration, washing, column chromatography separation, concentration, and recrystallization in sequence.

[0022] To achieve the above objectives, the third aspect of the present invention also provides a perovskite solar cell, comprising a stacked substrate layer, an electron transport layer, a perovskite light absorbing layer, a hole transport layer and an electrode layer, wherein the material of the hole transport layer is the hole transport material mentioned above or the hole transport material obtained by the preparation method of the hole transport material mentioned above.

[0023] Compared with the prior art, the hole transport layer material of the perovskite solar cell of the present invention has excellent semiconductor properties and can be used with the Pb 2+ The ion bonding has an interface passivation effect, so the perovskite solar cell of the present invention has good energy conversion efficiency, stability and service life.

[0024] Furthermore, the present invention adopts vacuum evaporation or liquid phase spin coating to form the hole transport layer. Since the o-phenanthroline metal complex shown in Formula 1 has good solubility in organic solvents, the hole transport layer can be prepared by a low-cost liquid phase spin coating process. Therefore, the present invention preferably adopts the liquid phase spin coating method to form the hole transport layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the structure of the perovskite solar cell of the present invention.

[0026] Figure 2 This is the nuclear magnetic resonance spectrum of the TPA-containing o-phenanthroline ligand prepared in Example 1.

[0027] Figure 3Graph showing the IV curve of a perovskite solar cell containing the hole transport material of Example 2.

[0028] Figure 4 The graph is a graph showing the change in the photoelectric conversion efficiency of a perovskite solar cell containing the hole transport material of Example 2 in air over time.

[0029] Figure 5 This is a curve chart showing the change in device photoelectric conversion efficiency of a perovskite solar cell containing the hole transport material of Comparative Example 1 in air over time. DETAILED DESCRIPTION

[0030] To better illustrate the purpose, technical solutions and beneficial effects of the present invention, the present invention will be further described below with reference to specific embodiments and accompanying drawings. It should be noted that the following implementation method is a further explanation of the present invention and should not be regarded as a limitation of the present invention.

[0031] Please see Figure 1 The present invention provides a perovskite solar cell 100, comprising a stacked substrate layer 110, an electron transport layer 120, a perovskite light absorbing layer 130, a hole transport layer 140, and an electrode layer 150. The hole transport material of the hole transport layer 140 comprises a phenanthroline metal complex as shown in Formula 1. The hole transport material of the hole transport layer 140 of the perovskite solar cell 100 of the present invention has excellent semiconductor properties and can react with the Pb that is not fully coordinated on the surface of the perovskite light absorbing layer 130. 2+ The ion bonding has an interface passivation effect, so the perovskite solar cell 100 of the present invention has good energy conversion efficiency, stability and service life.

[0032] Furthermore, the thickness of the substrate layer 110 of the present invention is 5 to 20 nm. Specifically, the thickness of the substrate layer 110 may be, but is not limited to, 5 nm, 6.5 nm, 8 nm, 9.5 nm, 10 nm, 10.5 nm, 11 nm, 11.5 nm, 12 nm, 12.5 nm, 15 nm, 17 nm, 18 nm, 19 nm, or 20 nm. The substrate layer 110 is made of a transparent conductive material widely recognized and applied in the field of perovskite solar cell technology. For example, the substrate layer 110 may be made of indium tin oxide (ITO) or fluorine-doped tin dioxide (FTO); preferably, the substrate layer 110 is indium tin oxide (ITO).

[0033] Furthermore, the thickness of the electron transport layer 120 of the present invention is 5 to 30 nm. Specifically, the thickness of the electron transport layer 120 may be, but is not limited to, 5 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, 17 nm, 18 nm, 19 nm, 20 nm, 22 nm, 24 nm, 25 nm, 27 nm, 28 nm, 29 nm, and 30 nm. The preparation material of the electron transport layer 120 is tin dioxide; it is understandable that the material of the electron transport layer 120 is not limited to tin dioxide, such as zinc oxide (ZnO), barium strontium titanate (BaSrTiO3), lithium nickel oxide (LiNiO2), etc. can also be used as the preparation material of the electron transport layer 120.

[0034] Furthermore, the thickness of the perovskite light absorbing layer 130 of the present invention is 100 to 800 nm. Specifically, the thickness of the perovskite light absorbing layer 130 may be, but is not limited to, 100 nm, 160 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, 550 nm, 600 nm, 650 nm, 700 nm, 750 nm, and 800 nm. The preparation material of the perovskite light absorbing layer 130 may be a perovskite light absorbing material commonly used in the art, such as the perovskite light absorbing layer 130 may be made of CH3NH3PbI3 or CH3NH 3-x PbCl x Made.

[0035] Furthermore, the thickness of the electrode layer 150 of the present invention is 30 to 150 nm. Specifically, the thickness of the electrode layer 150 may be, but is not limited to, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, or 150 nm. More specifically, the electrode layer 150 may be made of gold. Of course, the material of the electrode layer 150 is not limited to this, and may also be aluminum or silver.

[0036] It is worth noting that the preparation method of the perovskite solar cell involved in the present invention, such as the preparation steps of the substrate layer 110, the preparation steps of the electron transport layer 120, the preparation steps of the perovskite light absorbing layer 130, and the preparation steps of the electrode layer 150, are well known to those skilled in the art and will not be described in detail here.

[0037] Furthermore, the thickness of the hole transport layer 140 of the present invention is 30 to 100 nm. Specifically, the thickness of the hole transport layer 140 may be, but is not limited to, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, or 100 nm. More specifically, the hole transport material shown in Formula 1 may be formed into the hole transport layer 140 by vacuum evaporation or liquid phase spin coating. Since the o-phenanthroline metal complex shown in Formula 1 has good solubility in organic solvents, the hole transport layer 140 may be prepared by a low-cost liquid phase spin coating process. Therefore, the present invention preferably uses a liquid phase spin coating method to form the hole transport layer 140.

[0038] To facilitate understanding of how the hole transport material functions in the perovskite solar cell 100 , the hole transport material and the method for preparing the hole transport material of the present invention will be described in more detail below.

[0039] The present invention provides a hole transport material, comprising a phenanthroline metal complex as shown in Formula 1:

[0040]

[0041] M is a divalent metal ion; X is a halogen ion. The o-phenanthroline metal complex shown in Formula 1 of the present invention has excellent semiconductor properties, which can efficiently participate in the charge transfer process, thereby significantly improving the energy conversion efficiency of solar cells. In addition, the physical, electronic and optical properties thereof can be regulated by changing the divalent metal elements therein to adapt to different working environments and application requirements. In particular, the halogen ions contained in the o-phenanthroline metal complex can react with the Pb that is not fully coordinated on the surface of the perovskite light-absorbing layer. 2+ Ionic binding has an interfacial passivation effect, reducing the ineffective loss of carriers, thereby effectively improving the device stability and service life of the solar cell. In addition, the o-phenanthroline metal complex shown in Formula 1 is easy to obtain and low in cost, providing a basis for large-scale production and application. This also shows that the present invention uses the o-phenanthroline metal complex shown in Formula 1 to solve the problem of high cost and poor stability of the hole transport material of traditional perovskite solar cells caused by the need to introduce dopants.

[0042] Furthermore, M of the present invention is a copper ion (Cu 2+ ), zinc ions (Zn 2+ ), cobalt ions (Co 2+ ), nickel ions (Ni 2+ ), ferrous ions (Fe 2+ ), manganese ions (Mn 2+ ), lead ions (Pb 2+ ), platinum ions (Pt 2+ ) or palladium ions (Pd 2+), X is F - 、Cl - Br - or I - .

[0043] Accordingly, the method for preparing the hole transport material of the present invention comprises the following steps:

[0044] (1) mixing a TPA-containing o-phenanthroline ligand shown in Formula 2, a divalent metal halide, and an organic solvent and reacting the mixture;

[0045] (2) post-treating the reaction product obtained in step (1);

[0046]

[0047] As can be seen from the above steps (1) and (2), the present invention can obtain a hole transport material by directly reacting the compound represented by Formula 2, a divalent metal halide and an organic solvent. Therefore, the preparation method of the hole transport material provided by the present invention has simple preparation steps, is easy to industrialize, and uses low-cost raw materials.

[0048] Furthermore, the organic solvent of the present invention is chloroform, dichloromethane, ethanol, methanol, tetrahydrofuran, dimethylformamide or dimethyl sulfoxide.

[0049] Furthermore, in step (1) of the present invention, the molar ratio of the o-phenanthroline ligand containing a TPA group as shown in Formula 2 to the divalent metal halide is 1 to 5:1. Specifically, the molar ratio of the compound shown in Formula 2 to the divalent metal halide may be, but is not limited to, 1:1, 2:1, 3:1, 4:1, or 5:1. In order to increase the yield of the o-phenanthroline metal complex shown in Formula 1, the molar ratio of the o-phenanthroline ligand containing a TPA group to the divalent metal halide is preferably 2 to 5:1.

[0050] Furthermore, the reaction conditions in step (1) of the present invention are: reaction at room temperature to 100°C for 2 to 24 hours. Room temperature generally refers to 10°C to 30°C. Specifically, the reaction temperature can be, but is not limited to, 10°C, 12°C, 15°C, 18°C, 25°C, 28°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 98°C, or 100°C; the reaction time can be, but is not limited to, 2h, 3h, 4h, 5h, 7h, 9h, 10h, 12h, 14h, 15h, 16.5h, 18h, 19h, 20h, 21h, 22h, 23h, or 24h.

[0051] Furthermore, in step (1) of the present invention, the divalent metal halide includes CuX2, ZnX2, CoX2, NiX2, FeX2, MnX2, PbX2, PtX2 or PdX2, wherein X is F, Cl, Br or I. For example, the divalent metal halide may be, but is not limited to, CuCl2, CuBr2, CuF2, ZnCl2, CoCl2, NiCl2, PbI, and the like.

[0052] Furthermore, the preparation of the TPA-group-containing o-phenanthroline ligand represented by Formula 2 of the present invention includes: reacting 4-boronate-4',4'-dimethoxytriphenylamine (cas: 875667-84-8), 3,8-dibromo-1,10-phenanthroline (cas: 100125-12-0), and tetrakis(triphenylphosphine)palladium (cas: 14221-01-3) with potassium carbonate in a solvent at a molar ratio of 2-3:1:0.1-0.15:20-50 to obtain the obtained product. Specifically, the molar ratio of 4-boronate-4',4'-dimethoxytriphenylamine, 3,8-dibromo-1,10-phenanthroline, tetrakis(triphenylphosphine)palladium and potassium carbonate can be, but is not limited to, 2:1:0.1:20, 2.5:1:0.12:30, 3:1:0.1:40, or 2.2:1:0.15:50.

[0053] Furthermore, the present invention also includes dissolving potassium carbonate in water to produce a K2CO3 aqueous solution, and then mixing the K2CO3 aqueous solution with N,N-dimethylformamide (DMF) and stirring uniformly to produce a K2CO3 N,N-dimethylformamide / water solution. Specifically, the solvent of the present invention can be composed of N,N-dimethylformamide and water in a volume ratio of 1:1-2, and the concentration of potassium carbonate in the solvent is 0.3-1M. More specifically, the volume ratio of N,N-dimethylformamide to water can be, but is not limited to, 1:1, 1:1.5, 1:1.8, or 1:2. More specifically, the concentration of potassium carbonate in the solvent can be, but is not limited to, 0.3M, 0.5M, 0.8M, or 1M.

[0054] Furthermore, in step (2) of the present invention, the post-treatment includes filtering, washing, column chromatography separation, concentration, and recrystallization in sequence. Specifically, an organic solvent (such as dichloromethane, chloroform, methanol, ethanol, tetrahydrofuran, dimethylformamide, dimethyl sulfoxide, etc.) can be used for washing. Column chromatography separation is a routine operation in this field, such as using SiO2 to fill the chromatographic column and using a mixture of ethanol and dichloromethane as an eluent. Specifically, concentration is also a routine operation in this field, such as using a rotary evaporator for concentration. Recrystallization is also a routine operation in this field, and the reagent used can also be a mixture of ethanol and dichloromethane.

[0055] In order to illustrate the purpose, technical solutions and beneficial effects of the present invention in more detail, further description will be given below in conjunction with specific embodiments.

[0056] Example 1

[0057] This embodiment provides a method for preparing a TPA-containing o-phenanthroline ligand as shown in Formula 2, comprising the following steps:

[0058] (1) Mix 12 ml of 2 M K2CO3 aqueous solution and 18 ml of anhydrous N,N-dimethylformamide (DMF) and stir until uniformly mixed to prepare a K2CO3 water / DMF solution;

[0059] (2) 4-Borate-4',4'-dimethoxytriphenylamine (853 mg, 2 mmol), 3,8-dibromo-1,10-phenanthroline (338 mg, 1 mmol), tetrakis(triphenylphosphine)palladium (116 mg, 0.1 mmol) and K2CO3 in water / DMF solution were placed in a 100 ml two-necked round-bottom flask. Under argon protection, the mixture was heated at 120°C with stirring for 12 h and then cooled to room temperature.

[0060] (3) Filter the reaction mixture obtained after step (2), wash the solid on the filter paper with chloroform (3×20 ml), collect the filtrate, transfer the filtrate to a separatory funnel, wash the organic phase with saturated brine (3×30 ml) and deionized water (3×30 ml) in sequence, and then separate the organic phase;

[0061] (4) The organic phase was dried over anhydrous Na2SO3, then filtered, and the organic solvent was removed using a rotary evaporator to obtain a crude product;

[0062] (5) Purifying the crude product by column chromatography, using a SiO2-filled column and a mixed solvent of ethanol / dichloromethane (volume ratio of 1 / 4) as an eluent, collecting the product solution, and evaporating the solvent in the product solution using a rotary evaporator;

[0063] (6) The product of step (5) is recrystallized in hot methanol to obtain a 1,2-diaminophenanthroline ligand containing a TPA group.

[0064] The above-prepared 1,2-diaminophenanthroline ligand containing TPA group was characterized by nuclear magnetic resonance. The nuclear magnetic resonance spectrum is shown in FIG. Figure 2 shown.

[0065] Depend on Figure 2 It can be seen that the nuclear magnetic resonance hydrogen spectrum data of the o-phenanthroline ligand containing TPA group is: 1HNMR (CDCl3, 400MHz) δ9.39 (s, 2H), 8.31 (s, 2H), 7.82 (s, 2H), 7.61-7.59 (m, 4H), 7.14-7.06 (m, 12H), 6.89-6.86 (m, 8H), 3.82 (s, 12H); It can be confirmed that the structure of the o-phenanthroline ligand containing the TPA group is shown in Formula 2 below:

[0066]

[0067] Example 2

[0068] This embodiment provides a hole transport material, including a phenanthroline metal complex shown in the following compound 1:

[0069]

[0070] The method for preparing the hole transport material of this embodiment includes the following steps:

[0071] (1) 15.8 mmol CuCl2, 31.6 mmol of the TPA-containing o-phenanthroline ligand obtained in Example 1, and 100 ml of anhydrous ethanol were placed in a 200 ml single-necked round-bottom flask, a magnetic rotor was placed, a dropping funnel and a condenser were connected, and the mixture was stirred at 60°C for 2 h and cooled to room temperature;

[0072] (2) The reaction product obtained in step (1) is filtered, washed with ethanol, dissolved with dichloromethane, concentrated by rotary evaporation, separated by column chromatography using a mixed solvent of ethanol / dichloromethane (volume ratio of 1 / 3) as an eluent, concentrated by rotary evaporation, and recrystallized in an ethanol / dichloromethane solvent system.

[0073] Example 3

[0074] This embodiment provides a hole transport material, including a phenanthroline metal complex shown in the following compound 2:

[0075]

[0076] The method for preparing the hole transport material of this embodiment includes the following steps:

[0077] (1) 15.8 mmol ZnCl2, 31.6 mmol of the TPA-containing o-phenanthroline ligand obtained in Example 1, and 100 ml of anhydrous ethanol were placed in a 200 ml single-necked round-bottom flask, a magnetic rotor was placed, a dropping funnel and a condenser were connected, and the mixture was stirred at 60°C for 2 h and cooled to room temperature;

[0078] (2) The reaction product obtained in step (1) is filtered, washed with ethanol, dissolved with dichloromethane, concentrated by rotary evaporation, separated by column chromatography using a mixed solvent of ethanol / dichloromethane (volume ratio of 1 / 3) as an eluent, concentrated by rotary evaporation, and recrystallized in an ethanol / dichloromethane solvent system.

[0079] Example 4

[0080] This embodiment provides a hole transport material, including a phenanthroline metal complex shown in the following compound 3:

[0081]

[0082] The method for preparing the hole transport material of this embodiment includes the following steps:

[0083] (1) 15.8 mmol of CoCl2, 31.6 mmol of the TPA-containing o-phenanthroline ligand obtained in Example 1, and 100 ml of anhydrous ethanol were placed in a 200 ml single-necked round-bottom flask. A magnetic rotor was placed, and a dropping funnel and a condenser were connected. The mixture was stirred at 60°C for 2 h and cooled to room temperature.

[0084] (2) The reaction product obtained in step (1) is filtered, washed with ethanol, dissolved with dichloromethane, concentrated by rotary evaporation, separated by column chromatography using a mixed solvent of ethanol / dichloromethane (volume ratio of 1 / 3) as an eluent, concentrated by rotary evaporation, and recrystallized in an ethanol / dichloromethane solvent system.

[0085] Example 5

[0086] This embodiment provides a hole transport material, including a phenanthroline metal complex shown in the following compound 4:

[0087]

[0088] The method for preparing the hole transport material of this embodiment includes the following steps:

[0089] (1) 15.8 mmol of NiCl2, 31.6 mmol of the TPA-containing o-phenanthroline ligand obtained in Example 1, and 100 ml of anhydrous ethanol were placed in a 200 ml single-necked round-bottom flask, a magnetic rotor was placed, a dropping funnel and a condenser were connected, and the mixture was stirred at 60°C for 2 h and cooled to room temperature;

[0090] (2) The reaction product obtained in step (1) is filtered, washed with ethanol, dissolved with dichloromethane, concentrated by rotary evaporation, separated by column chromatography using a mixed solvent of ethanol / dichloromethane (volume ratio of 1 / 3) as an eluent, concentrated by rotary evaporation, and recrystallized in an ethanol / dichloromethane solvent system.

[0091] Example 6

[0092] This embodiment provides a hole transport material, including a phenanthroline metal complex shown in the following compound 5:

[0093]

[0094]

[0095] The method for preparing the hole transport material of this embodiment includes the following steps:

[0096] (1) 15.8 mmol of CuBr2, 31.6 mmol of the TPA-containing o-phenanthroline ligand obtained in Example 1, and 100 ml of anhydrous ethanol were placed in a 200 ml single-necked round-bottom flask. A magnetic rotor was placed, and a dropping funnel and a condenser were connected. The mixture was stirred at 60°C for 2 h and cooled to room temperature.

[0097] (2) The reaction product obtained in step (1) is filtered, washed with ethanol, dissolved with dichloromethane, concentrated by rotary evaporation, separated by column chromatography using a mixed solvent of ethanol / dichloromethane (volume ratio of 1 / 3) as an eluent, concentrated by rotary evaporation, and recrystallized in an ethanol / dichloromethane solvent system.

[0098] Example 7

[0099] This embodiment provides a hole transport material, including a phenanthroline metal complex shown in the following compound 6:

[0100]

[0101] The method for preparing the hole transport material of this embodiment includes the following steps:

[0102] (1) 15.8 mmol of CuF2, 31.6 mmol of the TPA-containing o-phenanthroline ligand obtained in Example 1, and 100 ml of anhydrous ethanol were placed in a 200 ml single-necked round-bottom flask. A magnetic rotor was placed, and a dropping funnel and a condenser were connected. The mixture was stirred at 60°C for 2 h and cooled to room temperature.

[0103] (2) The reaction product obtained in step (1) is filtered, washed with ethanol, dissolved with dichloromethane, concentrated by rotary evaporation, separated by column chromatography using a mixed solvent of ethanol / dichloromethane (volume ratio of 1 / 3) as an eluent, concentrated by rotary evaporation, and recrystallized in an ethanol / dichloromethane solvent system.

[0104] Example 8

[0105] This embodiment provides a hole transport material, including a phenanthroline metal complex shown in the following compound 7:

[0106]

[0107] The method for preparing the hole transport material of this embodiment includes the following steps:

[0108] (1) 15.8 mmol of PbI2, 31.6 mmol of the TPA-containing o-phenanthroline ligand obtained in Example 1, and 100 ml of anhydrous ethanol were placed in a 200 ml single-necked round-bottom flask. A magnetic rotor was placed, and a dropping funnel and condenser were connected. The mixture was stirred at 60°C for 2 h and cooled to room temperature.

[0109] (2) The reaction product obtained in step (1) is filtered, washed with ethanol, dissolved with dichloromethane, concentrated by rotary evaporation, separated by column chromatography using a mixed solvent of ethanol / dichloromethane (volume ratio of 1 / 3) as an eluent, concentrated by rotary evaporation, and recrystallized in an ethanol / dichloromethane solvent system.

[0110] Example 9

[0111] This embodiment provides a hole transport material, including a phenanthroline metal complex shown in the following compound 1:

[0112]

[0113] The method for preparing the hole transport material of this embodiment includes the following steps:

[0114] (1) 15.8 mmol CuCl2, 47.4 mmol of the TPA-containing o-phenanthroline ligand obtained in Example 1, and 100 ml of anhydrous ethanol were placed in a 200 ml single-necked round-bottom flask, a magnetic rotor was placed, a dropping funnel and a condenser were connected, and the mixture was stirred at 70°C for 4 h and cooled to room temperature;

[0115] (2) The reaction product obtained in step (1) is filtered, washed with ethanol, dissolved with dichloromethane, concentrated by rotary evaporation, separated by column chromatography using a mixed solvent of ethanol / dichloromethane (volume ratio of 1 / 3) as an eluent, concentrated by rotary evaporation, and recrystallized in an ethanol / dichloromethane solvent system.

[0116] Comparative Example 1

[0117] This comparative example provides a hole transport layer material of spiro-OMeTAD (2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene).

[0118] This comparative example provides a method for preparing a hole transport layer material, comprising the following steps:

[0119] (1) Prepare a 100 mg / mL spiro-OMeTAD solution in chlorobenzene under nitrogen atmosphere.

[0120] (2) 15.92 mL of 4-tert-butylpyridine and 9.68 mL of 520 mg / mL acetonitrile solution of lithium bis(trifluoromethanesulfonyl)imide were directly added to 0.3 mL of the above solution.

[0121] The hole transport materials of Examples 2 to 9 and Comparative Example 1 were applied to the perovskite solar cell according to the following preparation method of the perovskite solar cell.

[0122] Preparation method of perovskite solar cells:

[0123] (1) Preparation of FTO substrate layer

[0124] The etched transparent conductive substrate FTO was ultrasonically placed in a cleaning agent, deionized water, anhydrous ethanol, acetone, and isopropanol for 15 minutes in sequence. After being taken out, it was blown dry with nitrogen (N2), placed in an oven, dried at 120°C for 8 hours, and treated with UV / ozone for 30 minutes to obtain an FTO substrate layer with a thickness of 10 nm.

[0125] (2) Preparation of tin dioxide electron transport layer

[0126] A 0.1 mol / L stannous chloride (SnCl2·2H2O) ethanol solution was prepared and spin-coated onto the FTO substrate at a speed of 3000 rpm for 40 seconds. The resulting film was then annealed in air at 180°C for 1 hour to form a 15 nm thick tin dioxide electron transport layer.

[0127] (3) Preparation of CH3NH3PbI3 perovskite light-absorbing layer

[0128] In an N2 atmosphere, 461 mg of lead iodide (PbI2), 159 mg of methylammonium iodide (CH3NH3I), and 78 mg of dimethyl sulfoxide (DMSO) were dissolved in 600 mg of dimethylformamide (DMF) and stirred at room temperature for 1 hour to form a solution. 100 μL of this solution was spin-coated onto the tin dioxide electron transport layer using a spin coater at 4000 rpm for 20 seconds. 0.5 mL of ether or 0.3 mL of chlorobenzene was added during the spin coating process to improve film quality. The resulting CH3NH3PbI3 film was annealed at 65°C for 2 minutes and then at 100°C for 5 minutes to produce a CH3NH3PbI3 perovskite light-absorbing layer with a thickness of 600 nm.

[0129] (4) Preparation of hole transport layer

[0130] The hole transport materials of Examples 2 to 9 were deposited on the surface of the perovskite light absorbing layer by high vacuum thermal evaporation method to form a hole transport layer. -6 Pa vacuum degree, The hole transport material is evaporated and deposited at a rate of 100 nm to form a hole transport layer, and the thickness of the hole transport layer is controlled to be 80 nm;

[0131] The hole transport material of Comparative Example 1 was formed into a hole transport layer on the surface of the above-mentioned perovskite light absorption layer by a liquid phase spin coating method. The hole transport material was spin-coated into a film on the perovskite light absorption layer using a spin coater at a rotation speed of 4000 rpm for 45 seconds. The thickness of the spiro-OMeTAD hole transport layer was controlled to be 80 nm.

[0132] (5) Preparation of gold electrode layer

[0133] The gold electrode layer was prepared on the surface of the hole transport layer by high vacuum thermal evaporation method. -6 Pa vacuum degree, A gold electrode layer was prepared by rate evaporation deposition, and the thickness of the electrode layer was controlled to be 100 nm to obtain a perovskite solar cell.

[0134] The efficiency performance of the perovskite solar cells of the above embodiments and comparative examples was tested, wherein the effective area of ​​the perovskite solar cell device was 0.08 cm 2 Test conditions: spectral distribution AM1.5G, light intensity 100mW / cm 2 , AAA solar simulator (Beijing Zhuoli Hanguang Company), JV curve was measured by Keithly2400 digital source meter, all devices were simply packaged with UV glue, and the test was measured normally in the atmospheric environment. The open circuit voltage, short circuit current density, fill factor and conversion efficiency of the perovskite solar cell were calculated based on the obtained IV curve. The results are shown in Table 1. Specifically, the IV curve of the perovskite solar cell containing the hole transport material of Example 2 is as follows Figure 3 As shown; the curve of the change of the device photoelectric conversion efficiency of the perovskite solar cell containing the hole transport material of Example 2 in air over time is shown as follows Figure 4 The curve of the photoelectric conversion efficiency of the perovskite solar cell containing the hole transport material of Comparative Example 1 in air over time is shown as follows: Figure 5 shown.

[0135] Table 1 Performance test results of perovskite solar cells

[0136]

[0137]

[0138] From Table 1 and Figures 3-4 It can be seen that the perovskite solar cell containing the hole transport material of Example 2 still maintains more than 90% of the initial efficiency after being stored in an atmospheric environment for 1000 hours. In addition, experiments have shown that the time-dependent curve of the photoelectric conversion efficiency of the perovskite solar cell containing the hole transport material of Examples 3 to 9 in air is roughly the same as that of Example 1, that is, the photoelectric conversion efficiency of the perovskite solar cell containing the hole transport material of Examples 3 to 9 is greater than 16%, and the device can maintain more than 90% of the initial efficiency after being stored in an atmospheric environment for 1000 hours.

[0139] Depend on Figure 5 It can be seen that the device efficiency of the perovskite solar cell containing the hole transport material of Comparative Example 1 decays significantly in the atmospheric environment. After 800 hours, the efficiency is only 48% of the initial efficiency. This also shows that the hole transport material of the traditional perovskite solar cell has the problem of poor stability due to the introduction of metal lithium salt dopants.

[0140] In summary, the present invention uses the o-phenanthroline metal complex shown in Formula 1 as the hole transport material of the transport layer of the perovskite solar cell, which has low cost and can ensure that the perovskite solar cell has good open circuit voltage, short circuit current density, fill factor, conversion efficiency, device stability and service life.

[0141] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, it is not limited to the embodiments. Those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A hole transport material, characterized in that Including the o-phenanthroline metal complex shown in formula 1: Formula 1 M is Cu 2+ 、Zn 2+ 、Co 2+ 、Ni 2+ 、Fe 2+ 、Mn 2+ , Pb 2+ , Pt 2+ or Pd 2+ ; X is a halogen ion.

2. The hole transport material according to claim 1, wherein X is F - 、Cl - Br - or I - .

3. A method for preparing a hole transport material according to any one of claims 1 to 2, characterized in that: The following steps are involved: (1) mixing a TPA-containing o-phenanthroline ligand shown in formula 2, a divalent metal halide, and an organic solvent and reacting the mixture; (2) post-treating the reaction product obtained in step (1); The divalent metal halide in step (1) includes CuX2, ZnX2, CoX2, NiX2, FeX2, MnX2, PbX2, PtX2 or PdX2; Formula 2.

4. The method for preparing a hole transport material according to claim 3, wherein: The molar ratio of the o-phenanthroline ligand containing a TPA group to the divalent metal halide in step (1) is 1 to 5:

1.

5. The method for preparing a hole transport material according to claim 3, wherein: The reaction conditions in step (1) are: reaction at room temperature to 100° C. for 2 to 24 hours.

6. The method for preparing a hole transport material according to claim 3, wherein: X is F, Cl, Br or I.

7. The method for preparing a hole transport material according to claim 3, wherein: The preparation of the o-phenanthroline ligand containing a TPA group comprises: reacting 4-borate-4',4'-dimethoxytriphenylamine, 3,8-dibromo-1,10-phenanthroline, tetrakis(triphenylphosphine)palladium and potassium carbonate in a molar ratio of 2-3:1:0.1-0.15:20-50 in a solvent to obtain the obtained product.

8. The method for preparing a hole transport material according to claim 7, wherein: The solvent consists of N,N-dimethylformamide and water in a volume ratio of 1:1-2, and the concentration of potassium carbonate in the solvent is 0.3-1M.

9. The method for preparing a hole transport material according to claim 3, wherein: The post-treatment in step (2) includes filtration, washing, column chromatography separation, concentration, and recrystallization in sequence.

10. A perovskite solar cell comprising a stacked substrate layer, an electron transport layer, a perovskite light absorbing layer, a hole transport layer and an electrode layer, characterized in that: The material of the hole transport layer is the hole transport material according to any one of claims 1 to 2 or the hole transport material prepared by the preparation method of the hole transport material according to any one of claims 3 to 9.

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