Hole transport material and preparation method thereof, perovskite solar cell and preparation method thereof

Abstract

The invention discloses a hole transport material and a preparation method thereof, and a perovskite solar cell and a preparation method thereof. The hole transport material comprises at least one of structures shown in a formula 1: in the formula 1 # imgabs0 #, R is selected from any one of hydrogen, chlorine group, bromine group, methoxyl and dimethylamino; in the formula 1, Ar is independently selected from any one of hydrogen, C1-C20 linear alkyl, C1-C20 branched alkyl, C1-C15 alkoxy and a group as shown in a formula 2; in the formula 2 # imgabs 1 # and the formula 2, R2 is independently selected from any one of hydrogen, linear alkyl of C1-C20, branched alkyl of C1-C20, alkoxy of C1-C20, phenyl, p-methoxyphenyl, 4, 4 '-dimethoxybenzidine, p-tert-butylphenyl and carbazolyl, and R2 is independently selected from any one of hydrogen, linear alkyl of C1-C20, branched alkyl of C1-C20, alkoxy of C1-C20, phenyl, p-methoxyphenyl, 4, 4'-dimethoxybenzidine, p-tert-butylphenyl and carbazolyl. The dashed line represents a replacement position. The energy levels of the perovskite light absorption layer and the hole transport layer can be better matched, and the photoelectric conversion efficiency of the perovskite solar cell is improved.

Description

Technical Field

[0001] This application belongs to the technical field of perovskite solar cells, and specifically relates to a hole transport material and a preparation method thereof, a perovskite solar cell and a preparation method thereof. Background Art

[0002] Perovskite solar cells (PSCs) have the characteristics of high photoelectric conversion efficiency, high adjustment flexibility, low preparation cost, etc., and are applied in the field of photovoltaic power generation, with great commercial application potential. Perovskite solar cells include inverted structure cells (p-i-n) and normal structure cells (n-i-p). Taking the inverted structure cell as an example, the inverted structure cell has the advantages of low hysteresis, simple preparation, strong stability, etc., and is an ideal structure for commercial cells.

[0003] In the inverted structure cell, the hole transport layer (HTL) is the first functional layer to be prepared, mainly playing the role of blocking electrons and transporting holes. At the same time, the application of the hole transport material can play a role in adjusting the energy level arrangement at the interface, improving the contact between the perovskite light-absorbing layer and the anode. Therefore, the selection of the hole transport layer material has a crucial impact on the performance of perovskite battery devices. Regarding the problems of stability and commercial cost shown by organic hole transport layers such as PEDOT:PSS and PTAA, inorganic hole transport materials have emerged. Among them, nickel oxide (NiO x ) has attracted more and more attention due to its high transmittance, ideal valence band position, excellent chemical stability and easy preparation. Although, NiO x hole transport layer has the above advantages, but existing research technologies show that NiO x as the hole transport layer material of the inverted perovskite battery, problems such as energy level mismatch will occur, which is not conducive to the improvement of the photoelectric conversion efficiency of the battery. Summary of the Invention

[0004] This application aims to solve at least one of the technical problems in the related technologies to some extent. For this reason, an object of this application is to propose a hole transport material and a preparation method thereof, a perovskite solar cell and a preparation method thereof. The hole transport material proposed in this application is used in perovskite solar cells and serves as a modification layer of the hole transport layer, which is conducive to achieving a better energy level matching between the perovskite light-absorbing layer and the hole transport layer, and improving the photoelectric conversion efficiency of perovskite solar cells.

[0005] In one aspect of this application, this application proposes a hole transport material, including at least one of the structures shown in Formula 1:

[0006]

[0007] In Formula 1, R is selected from any one of hydrogen, chloro group, bromo group, methoxy group, and dimethylamino group; each Ar is independently selected from any one of hydrogen, a straight-chain alkyl group having 1 to 20 carbon atoms, a branched-chain alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 15 carbon atoms, and a group represented by Formula 2;

[0008]

[0009] In Formula 2, each R2 is independently selected from any one of hydrogen, a straight-chain alkyl group having 1 to 20 carbon atoms, a branched-chain alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, phenyl group, p-methoxyphenyl group, 4,4'-dimethoxydiphenylamine group, p-tert-butylphenyl group, and carbazolyl group; the dotted line represents the substitution position.

[0010] The pyridine-based parent nucleus organic small molecule provided by the present application can be used as a hole transport material in a perovskite solar cell and used as a modification material for a nickel oxide (NiO x ) hole transport layer to modify and passivate the hole transport layer, thereby adjusting the NiO x energy level to make it more matched with the energy level of the perovskite light-absorbing layer, enhancing the hole extraction ability and optimizing the interface in contact with the perovskite light-absorbing layer, so as to facilitate the preparation of a high-quality perovskite light-absorbing layer and a perovskite battery device with excellent photoelectric conversion performance.

[0011] In some embodiments, in Formula 1; at least one Ar is selected from the group represented by Formula 2-1, and the remaining Ar is selected from hydrogen:

[0012]

[0013] And / or, in Formula 2, R2 is selected from 4,4'-dimethoxydiphenylamine group.

[0014] In some embodiments, it includes at least one of the structures represented by Formula I to Formula X below:

[0015]

[0016] Among them, the dotted line represents the substitution position, and the CZ-DIDPA group has the structure represented by Formula 3:

[0017]

[0018] In some embodiments, the hole transport material includes at least one of the structures represented by the following formula:

[0019]

[0020] Among them, the dotted line represents the substitution position, and CZ-DIDPA has the structure represented by Formula 3:

[0021]

[0022] A second aspect of the present application provides a method for preparing a hole transporting material, comprising:

[0023] Performing a substitution reaction on raw material X and raw material Y to prepare a hole transporting material;

[0024] Wherein:

[0025] Raw material X includes and / or Raw material Y includes CZ-DIDPA, and CZ-DIDPA represents The hole transporting material includes and / or Wherein, R is independently selected from any one of hydrogen, chloro group, bromo group, methoxy group, and dimethylamino group.

[0026] In some embodiments, the preparation method of CZ-DIDPA includes

[0027] Reacting raw material a with raw material b to obtain intermediate product c;

[0028] Reacting intermediate product c with raw material d to obtain intermediate product e;

[0029] Performing a dealkylation reaction on intermediate product e to prepare CZ-DIDPA;

[0030] Wherein:

[0031] Raw material a includes Raw material b includes

[0032] Intermediate product c includes

[0033] Raw material d includes

[0034] Intermediate product e includes

[0035] In some embodiments, R is independently selected from any one of hydrogen, methoxy group, and dimethylamino group.

[0036] A third aspect of the present application provides a perovskite solar cell, comprising a hole transporting layer, and a modification layer is provided on at least one side of the hole transporting layer;

[0037] The hole transporting layer contains a second hole transporting material, and the second hole transporting material includes NiO x ;

[0038] The modification layer contains the hole transporting material proposed in the first aspect above, or contains the hole transporting material obtained by the method proposed in the second aspect above.

[0039] In some embodiments, the perovskite solar cell further includes a perovskite light-absorbing layer, and the modification layer is located between the hole transport layer and the perovskite light-absorbing layer;

[0040] The perovskite light-absorbing layer contains a perovskite material, and the perovskite material contains a metal halide perovskite material, and the chemical general formula of the metal halide perovskite material is ABX3; wherein, A represents a monovalent cation; B represents a divalent cation; X represents a monovalent anion.

[0041] A fourth aspect of the present application provides a method for preparing a perovskite solar cell, including:

[0042] Forming a hole transport layer on the first electrode; the hole transport layer contains a second hole transport material, and the second hole transport material includes NiO x .

[0043] Forming a modification layer on the hole transport layer, the modification layer contains the above-mentioned hole transport material, or contains the hole transport material prepared by the above method;

[0044] Forming a perovskite light-absorbing layer on the modification layer;

[0045] Forming an electron transport layer on the perovskite light-absorbing layer;

[0046] Forming a second electrode on the electron transport layer to obtain a perovskite solar cell.

[0047] Additional aspects and advantages of the present application will be given in part in the following description, will become apparent in part from the following description, or will be understood through the practice of the present invention. Description of the Drawings

[0048] Figure 1 is the 1H NMR spectrum of 9-benzyl 3,6-dibromo-9H-carbazole provided in Example A of the present application.

[0049] Figure 2 is the 1H NMR spectrum of Benzyl-Cz-DIDPA provided in Example A of the present application.

[0050] Figure 3 is the 1H NMR spectrum of Cz-DIDPA provided in Example A of the present application.

[0051] Figure 4 is the 1H NMR spectrum of 3,5-2CzDIDPA-PY provided in Example 1 of the present application.

[0052] Figure 5 is the mass spectrum of 3,5-2CzDIDPA-PY provided in Example 1 of the present application.

[0053] Figure 6 is the 1H NMR spectrum of 3,5-2CzDIDPA-DMAP provided in Example 2 of this application.

[0054] Figure 7 is the mass spectrum of 3,5-2CzDIDPA-DMAP provided in Example 2 of this application.

[0055] Figure 8 is the 1H NMR spectrum of 2,6-2CzDIDPA-DMAP provided in Example 3 of this application.

[0056] Figure 9 is the mass spectrum of 2,6-2CzDIDPA-DMAP provided in Example 3 of this application.

[0057] Figure 10 is the schematic diagram of the perovskite solar cell structure provided in the embodiment of this application; Reference numerals:

[0058] 1, transparent bottom electrode; 2, hole transport layer; 3, modification layer; 4, perovskite light-absorbing layer; 5, passivation layer; 6, electron transport layer; 7, top electrode.

[0059] Figure 11 is the J-V curve diagram comparing the cell with the modification layer of 3,5-2CzDIDPA-PY provided in Example 4 of this application and the cell provided in Comparative Example 1.

[0060] Figure 12 is the J-V curve diagram comparing the cell with the modification layer of 3,5-2CzDIDPA-DMAP provided in Example 5 of this application and the cell provided in Comparative Example 1.

[0061] Figure 13 is the J-V curve diagram comparing the cell with the modification layer of 2,6-2CzDIDPA-DMAP provided in Example 6 of this application and the cell provided in Comparative Example 1. Detailed implementation manners

[0062] The embodiments of the present invention are described in detail below, which are intended to explain the present invention and should not be construed as limiting the present invention.

[0063] Currently, nickel oxide has attracted more and more attention due to its high transmittance, ideal valence band position, excellent chemical stability and easy preparation, and it is a commonly used hole transport material in current inverted perovskite solar cells. Although, NiO x (refers to a mixed system of divalent and trivalent nickel oxides) hole transport layer has the above advantages, but existing research technologies show that NiO x when used as the hole transport layer of an inverted perovskite solar cell, problems such as energy level mismatch will occur. In addition, due to NiOx It is usually composed of a mixed system of divalent and trivalent nickel, which is prone to non-radiative recombination. Therefore, the energy level matching needs to be further adjusted, and the hole transport and extraction capabilities need to be further improved.

[0064] For this reason, in one aspect of the embodiments of the present application, the present application proposes a hole transport material, including at least one of the structures shown in Formula 1:

[0065]

[0066] In Formula 1, R is taken from any one of hydrogen, chloro group, bromo group, methoxy group, and dimethylamino group; each Ar is independently taken from any one of hydrogen, a straight-chain alkyl group with 1 to 20 carbon atoms, a branched-chain alkyl group with 1 to 20 carbon atoms, an alkoxy group with 1 to 15 carbon atoms, and a group shown in Formula 2;

[0067]

[0068] In Formula 2, R2 is independently taken from any one of hydrogen, a straight-chain alkyl group with 1 to 20 carbon atoms, a branched-chain alkyl group with 1 to 20 carbon atoms, an alkoxy group with 1 to 20 carbon atoms, phenyl group, p-methoxyphenyl group, 4,4'-dimethoxybiphenylamine group, p-tert-butylphenyl group, and carbazolyl group; the dotted line represents the substitution position.

[0069] The hole transport material provided by the embodiments of the present application is an organic small molecule with a pyridine-based nucleus, which can be applied to perovskite solar cells and used as a modification material for the hole transport layer of nickel oxide (NiO x ). The pyridine group in this organic small molecule structure has lone pair electrons, which can coordinate with trivalent nickel in NiO x , and can adjust the smooth energy level, solving the problem of better energy level matching between the NiO x hole transport layer and the perovskite light-absorbing layer.

[0070] In addition, the pyridine unit in the structure of the organic small molecule provided by the embodiments of the present application can act as a Lewis base and can combine with uncoordinated divalent cations (such as Pb 2+ ) at the bottom interface of the perovskite light-absorbing layer of the perovskite solar cell, thereby passivating the shallow surface defects at the interface contact between the perovskite light-absorbing layer and the hole transport layer, effectively suppressing the non-radiative recombination problem at the interface contact, and improving the interface contact effect. Through the above improvements, it is beneficial to finally obtain a high-quality perovskite light-absorbing layer with large grain size and low defect density, thereby improving the photoelectric conversion efficiency of the perovskite solar cell.

[0071] In some embodiments of the present application, in Formula 1 shown; at least one Ar is taken from a group shown in Formula 2-1, and the remaining Ar is taken from hydrogen:

[0072]

[0073] And / or, in Formula 2, R2 is selected from 4,4'-dimethoxydiphenylamine group.

[0074] The pyridine-based parent nucleus organic small molecule provided by the embodiment of the present application is used as an interfacial modification layer of the NiO x hole transport layer. The introduction of the triarylamine unit in its molecular structure effectively enhances the hole transport ability of the hole transport layer due to the strong electron-donating ability and excellent hole transport characteristics of this structure, thereby improving the optoelectronic performance of the perovskite solar cell device; the lone pair of electrons of the pyridine group in the molecular structure can coordinate with the trivalent nickel in NiO x to adjust the smooth energy level and solve the problem of better matching of the energy levels between the NiO x hole transport layer and the perovskite light-absorbing layer; the pyridine unit in the molecular structure can act as a Lewis base and can combine with the uncoordinated divalent cations (such as Pb 2+ ) at the bottom interface of the perovskite light-absorbing layer, thereby passivating the shallow surface defects at the interface contact and effectively suppressing the non-radiative recombination problem at the interface contact, and further facilitating better improvement of the photoelectric conversion efficiency of the perovskite solar cell.

[0075] In some embodiments of the present application, it includes at least one of the structures shown in Formula I to Formula X below:

[0076]

[0077] Among them, the dotted line represents the substitution position, and the CZ-DIDPA group has the structure shown in Formula 3:

[0078]

[0079] The hole transport material provided by the embodiment of the present application uses the pyridine group as the parent nucleus and conducts functional modification on it to form an organic small molecule with multi-functional sites that can synergistically modify and passivate the NiO x hole transport layer. The interfacial modification layer with these organic small molecules is beneficial to improving the interface contact between the NiO x hole transport layer and the perovskite light-absorbing layer, adjusting the energy level, increasing the hole extraction and transport ability of the hole transport layer, and further facilitating the improvement of the photoelectric conversion efficiency of the perovskite solar cell.

[0080] In some embodiments of the present application, it includes at least one of the structures shown in the following formula:

[0081]

[0082] Among them, the dotted line represents the substitution position, and CZ-DIDPA has the structure shown in Formula 3:

[0083]

[0084] The hole transport material provided by the embodiments of the present application is used as a modification material for the NiOx hole transport layer in a perovskite solar cell, and can effectively improve the photoelectric conversion efficiency of the perovskite solar cell.

[0085] Among them, the organic small molecule shown in Formula I has a molecular formula of C 85 H 71 N7O8, and a molar mass of 1317.110 g / mol; the organic small molecule shown in Formula II has a molecular formula of C 87 H 76 N8O8, and a molar mass of 1360.055 g / mol; the organic small molecule provided by Formula VII has a molecular formula of C 87 H 76 N8O8, and a molar mass of 1360.055 g / mol.

[0086] The second aspect of the embodiments of the present application proposes a method for preparing a hole transport material, including:

[0087] Performing a substitution reaction on raw material X and raw material Y to prepare a hole transport material;

[0088] Among them:

[0089] Raw material X includes and / or

[0090] Raw material Y includes CZ-DIDPA, and CZ-DIDPA represents

[0091] The hole transport material includes and / or

[0092] Among them, R is taken from any one of hydrogen, chloro group, bromo group, methoxy group, and dimethylamino group.

[0093] The hole transport material prepared by the method provided by the embodiments of the present application forms an organic small molecule with an electron-deficient pyridine unit as the mother nucleus and having multiple functional sites. This organic small molecule can be applied to the x hole transport layer interface modification layer of a perovskite battery, which is beneficial to improving the photoelectric conversion efficiency of the perovskite solar cell.

[0094] In some embodiments of the present application, the preparation method of CZ-DIDPA includes

[0095] Reacting raw material a with raw material b to obtain intermediate product c;

[0096] The intermediate product c is reacted with the raw material d to obtain the intermediate product e;

[0097] The intermediate product e is subjected to a dealkylation reaction to prepare CZ-DIDPA;

[0098] in:

[0099] Raw materials a include

[0100] Raw materials b include

[0101] Intermediate products c include

[0102] Raw materials include

[0103] Intermediate products include

[0104] In the step of subjecting the intermediate product e to a dealkylation reaction, "dealkylation" refers to removing the group (such as benzyl) connected to nitrogen on the carbazole group and replacing it with hydrogen to obtain CZ-DIDPA.

[0105] In some embodiments of the present application, R is independently selected from any one of hydrogen, methoxy, and dimethylamino.

[0106] In some embodiments of the present application, the method for preparing the hole transport material specifically comprises the steps of:

[0107] Synthetic intermediate product c, namely, 9-benzyl-3,6-dibromo-9H-carbazole (Benzyl-Cz):

[0108]

[0109] The raw material a (3,6-dibromocarbazole), the raw material b (benzyl bromide), potassium carbonate and a solvent (such as DMF) are mixed and reacted at room temperature to obtain an intermediate product c.

[0110] Synthetic intermediate product e, namely, synthesis of 9-benzyl-3,6-di(4,4'-dimethoxydiphenylamine)-9H-carbazole (Benzyl-Cz-DIDPA):

[0111]

[0112] The intermediate product c (Benzyl-Cz), the raw material d (4,4'-dimethoxydiphenylamine), tri-tert-butylphosphine tetrafluoroborate, salt, sodium tert-butoxide, palladium acetate, and toluene are mixed and heated to reflux under an inert atmosphere to obtain the intermediate product e.

[0113] Synthesis of 3,6-bis(4,4'-dimethoxydiphenylamino)-9H-carbazole (Cz-DIDPA):

[0114]

[0115] Mix Benzyl-Cz-DIDPA, potassium tert-butoxide, DMSO, and THF 2, and react at room temperature under an oxygen-containing atmosphere to obtain Cz-DIDPA.

[0116] Synthesis of hole transport material:

[0117]

[0118] Mix Cz-DIDPA, cesium carbonate, DMSO, and and / or and react under an inert atmosphere to obtain the hole transport material and / or

[0119] A third aspect of the embodiments of the present application provides a perovskite solar cell, including a hole transport layer, and a modification layer is provided on at least one side of the hole transport layer;

[0120] The hole transport layer contains a second hole transport material, and the second hole transport material includes NiO x ;

[0121] The modification layer contains the hole transport material proposed in the first aspect above, or contains the hole transport material obtained by the method proposed in the second aspect above.

[0122] The perovskite solar cell provided by the embodiments of the present application uses a modification layer to modify the nickel oxide hole transport layer and improve the interfacial contact effect between the perovskite light absorption layer and the hole transport layer. The material of the modification layer contains the hole transport material proposed in the first aspect above, or contains the hole transport material obtained by the method proposed in the second aspect above. It is an organic small molecule with a multi-functional site based on an electron-deficient pyridine unit, and this organic small molecule can be applied to the NiO x hole transport layer interface modification to improve the photoelectric conversion efficiency of the battery device.

[0123] In addition, in the embodiments of the present application, for the second hole transport material NiO x has the meaning well-known in the art. Usually, x takes values of 1 and 1.5. Correspondingly, NiO x refers to a mixture of Ni2O3 and NiO. Through improvement in the embodiments of the present application, the trivalent nickel can be reduced, and the ratio of Ni 2+ / Ni 3+ can be increased to improve the photoelectric conversion efficiency of the battery device.

[0124] In some embodiments of the present application, the perovskite solar cell further includes a perovskite light-absorbing layer, and the modification layer is located between the hole transport layer and the perovskite light-absorbing layer; the perovskite light-absorbing layer contains a perovskite material, and the perovskite material contains a metal halide perovskite material, and the chemical general formula of the metal halide perovskite material is ABX3; wherein, A represents a monovalent cation; B represents a divalent cation; X represents a monovalent anion.

[0125] Further, A includes a monovalent organic cation and / or a monovalent inorganic cation; as an example, A includes Rb + 、C s+ 、CH3NH3 + 、CH3CH2NH3 + 、CH3(CH2)2NH3 + 、CH3(CH2)3NH3 + 、HC(NH2)2 + or a combination of one or more of them.

[0126] Further, B includes a divalent inorganic cation, which can be Pb 2+ , or a combination of Pb 2+ and other divalent cations. As an example, B includes Pb 2+ 、Sn 2+ 、Cu 2+ , Ge 2+ or a combination of one or more of them.

[0127] Further, X includes a monovalent organic anion and / or a monovalent inorganic anion; as an example, X includes Cl - 、Br - 、I - 、SCN - 、BF4 - 、PF6 - or a combination of one or more of them.

[0128] In some embodiments of the present application, at least Pb 2+ is included in the divalent cations. Further, the divalent cations may also include Sn 2+ 、Cu 2+ , Ge 2+ or a combination of one or more of them.

[0129] In some embodiments of the present application, the perovskite solar cell further includes a first electrode, an electron transport layer, and a second electrode; the first electrode, the hole transport layer, the modification layer, the perovskite light-absorbing layer, the electron transport layer, and the second electrode are arranged in sequence.

[0130] The perovskite solar cell provided by the embodiment of the present application is a reverse perovskite solar cell. Using the pyridine-based parent nucleus organic small molecule provided by the embodiment of the present application in the modification layer is beneficial to better improving the optoelectronic conversion effect of the perovskite solar cell.

[0131] In some embodiments of the present application, the first electrode includes a transparent conductive substrate electrode, and the transparent conductive substrate electrode includes a substrate and a conductive layer; wherein, the substrate includes at least one of glass, steel plate, PET (polyethylene terephthalate), PI (polyimide), PEN (polyethylene naphthalate), flexible glass, and flexible steel plate; the conductive layer includes at least one of ITO (indium tin oxide), AZO (aluminum-doped zinc oxide), and FTO (fluorine-doped tin oxide).

[0132] In some embodiments of the present application, the electron transport layer includes TiO2, SnO2, ZnO, PC 61 BM, PC 71 BM, TIPD, ICBA, C 60 , one or several of BCP.

[0133] In some embodiments of the present application, the second electrode includes a metal electrode and a transparent oxide electrode;

[0134] As an example, the metal electrode includes materials with a relatively high work function, such as metals including gold, silver, copper, aluminum, etc.

[0135] As an example, the transparent oxide electrode includes one or several of ITO and IZO.

[0136] Furthermore, the preparation method of the second electrode includes one or several of evaporation, vacuum evaporation, magnetron sputtering, and multi-arc ion plating.

[0137] The fourth aspect of the embodiment of the present application proposes a method for preparing a perovskite solar cell, including:

[0138] Forming a hole transport layer on the first electrode; the hole transport layer contains a second hole transport material, and the second hole transport material includes NiO x ;

[0139] Forming a modification layer on the hole transport layer, the modification contains the hole transport material proposed in the first aspect of the embodiment of the present application, or contains the hole transport material prepared by the method proposed in the second aspect of the embodiment of the present application;

[0140] Forming a perovskite light-absorbing layer on the modification layer;

[0141] Forming an electron transport layer on the perovskite light-absorbing layer;

[0142] A second electrode is formed on the electron transport layer to obtain a perovskite solar cell.

[0143] The method for preparing a perovskite solar cell provided by the embodiments of the present application can form a modified layer containing a hole transport material on the surface of the nickel oxide hole transport layer, including the hole transport material proposed in the first aspect above, or the hole transport material obtained by the method proposed in the second aspect above, which is an organic small molecule with an electron-deficient pyridine unit as the parent nucleus and having multifunctional sites. This organic small molecule can be applied to the NiO of the perovskite cell x Modifying the hole transport layer interface improves the photoelectric conversion efficiency of the battery device.

[0144] In some embodiments of the present application, the method used in the step of forming a hole transport layer on the first electrode includes at least one of magnetron sputtering, electron beam evaporation, atomic layer deposition, sol-gel method, solution combustion method, and spray pyrolysis method; and / or, the step of forming a modified layer on the hole transport layer includes: coating a slurry containing an organic substance on the hole transport layer, and annealing to obtain the modified layer; the coating method includes at least one of doctor blade coating, spin coating, spraying, slot die coating, inkjet printing, or screen printing.

[0145] Some modified layers of the hole transport layer provided by the prior art, either have complex preparation methods or will limit the preparation method of the modified layer, and even limit the preparation method of the hole transport layer to only a specific method, which is not suitable for the commercial development and application of large-area perovskite battery technology.

[0146] In the method for preparing a perovskite solar cell provided by the embodiments of the present application, the pyridine-based parent nucleus organic small molecule used can be applied to various methods to form a modified layer, including but not limited to at least one of doctor blade coating, spin coating, spraying, slot die coating, inkjet printing, or screen printing; there are also various preparation methods for the applicable hole transport layer, including but not limited to at least one of magnetron sputtering, electron beam evaporation, atomic layer deposition, sol-gel method, solution combustion method, and spray pyrolysis method.

[0147] The organic small molecule interface modified layer containing a pyridine-based parent nucleus provided by the embodiments of the present application has a simple preparation process, can be prepared by a low-temperature solution method, and is easy to realize industrial large-scale production, thus realizing the preparation of a perovskite solar cell device with high photoelectric conversion efficiency, and opening up ideas for the commercialization of large-area perovskite battery technology.

[0148] In some embodiments of the present application, the specific steps of forming a modified layer on the hole transport layer include:

[0149] Dissolve the hole transport material (i.e., the pyridine-based parent nucleus organic small molecule) in a solvent to obtain a solution. Deposit the obtained solution on the surface of the hole transport layer by any one of spin coating, spray coating, slot die coating, inkjet printing, screen printing.

[0150] Perform annealing treatment to form an interface modification layer film.

[0151] Furthermore, the solution concentration is 0.1 mg / ml to 0.5 mg / ml; as an example, the solution concentrations are 0.1 mg / ml, 0.2 mg / ml, 0.3 mg / ml, 0.4 mg / ml, 0.5 mg / ml, etc.

[0152] Furthermore, the method for forming the solution includes one or more of shaking, ultrasonic treatment, heating, bubbling, magnetic stirring. As an example, a homogeneous and transparent solution containing the hole transport material can be formed by dissolving at room temperature with shaking.

[0153] Furthermore, the solvent includes one or more of N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), chlorobenzene, toluene, chloroform, N-methylpyrrolidone (NMP).

[0154] Furthermore, the annealing method includes at least one of an oven and a hot stage.

[0155] Furthermore, the annealing temperature is 90 °C to 120 °C, and the annealing time is 5 min to 15 min. As an example, the annealing temperatures are 90 °C, 95 °C, 100 °C, 105 °C, 110 °C, 115 °C, 120 °C, etc. As an example, the annealing times are 5 min, 7 min, 9 min, 11 min, 13 min, 15 min, etc.

[0156] In some embodiments of the present application, the method for preparing a perovskite solar cell device includes the following steps:

[0157] Form a nickel oxide hole transport layer on a transparent bottom electrode;

[0158] Coat a solution containing the hole transport material on the nickel oxide hole transport layer, and form a modification layer through annealing treatment;

[0159] Coat a perovskite precursor solution on the modification layer, and form a perovskite light-absorbing layer through annealing treatment;

[0160] Form a passivation layer on the perovskite light-absorbing layer;

[0161] Form an electron transport layer on the perovskite light-absorbing layer;

[0162] Form a metal electrode on the electron transport layer to obtain a perovskite solar cell.

[0163] In addition, corresponding functional layers can be set based on actual requirements. As an example, a passivation layer can be set between the perovskite light-absorbing layer and the electron transport layer, and a buffer layer can be set between the electron transport layer and the metal electrode.

[0164] The present invention will be described below with reference to specific embodiments. It should be noted that these embodiments are merely descriptive and do not limit the present invention in any way. The reagents used in the embodiments are all from Aladdin Biochemical Technology Co., Ltd.

[0165]

Preparation of Organic Compounds

[0166] Example A

[0167] Synthesis of 3,6-bis(4,4'-dimethoxydiphenylamino)-9H-carbazole (Cz-DIDPA):

[0168] (1) Synthesis of 9-benzyl-3,6-dibromo-9H-carbazole (Benzyl-Cz):

[0169]

[0170] Add 3.25 g (10 mmol) of 3,6-dibromocarbazole, 13.8 g (10 eq) of potassium carbonate, 2.4 mL (2 eq) of benzyl bromide, and 50 mL of DMF (N,N-dimethylformamide) to a 250 mL two-necked flask. The reaction system was stirred at room temperature overnight. After the reaction was completed, the reaction system was poured into ice water to precipitate a white solid to obtain the crude product. The crude product was dissolved in dichloromethane and poured into n-hexane for recrystallization. Filtration by suction gave 3.6 g of a white solid product with a yield of 88%. The synthetic route is shown in Reaction Scheme 1.

[0171] 1H NMR (400 MHz, DMSO) δ 8.52 (d, J = 1.8 Hz, 2H), 7.65 (d, J = 8.8 Hz, 2H), 7.60 (dd, J = 8.7, 1.9 Hz, 2H), 7.24 (dd, J = 12.5, 7.1 Hz, 3H), 7.12 (d, J = 6.8 Hz, 2H), 5.68 (s, 2H). The 1H NMR spectrum is shown in the appendix Figure 1 .

[0172] (2) Synthesis of 9-benzyl-3,6-bis(4,4'-dimethoxydiphenylamino)-9H-carbazole (Benzyl-Cz-DIDPA):

[0173]

[0174] In a 250mL double-necked bottle, add Cz-Benzyl 1.24g (3mmol), 4,4'-dimethoxydiphenylamine 1.51g (2.2eq), tri-tert-butylphosphine tetrafluoroborate ([(t-Bu)3P]BF4) 174mg (10%eq), sodium tert-butoxide ((t-Bu)3ONa) 1.44g (5eq) and palladium acetate (Pb(OAc)2) 68mg (5%eq) and anhydrous toluene (Toluene) 60mL, and heat under reflux for 24h under nitrogen protection. After the reaction is completed, pour the reaction system into deionized water, extract with dichloromethane, dry the organic phase with anhydrous sodium sulfate, remove the solvent by rotary evaporation under reduced pressure, separate by column chromatography, and obtain 1.86g of yellow-green solid with a yield of 85%. The synthetic route is shown in Reaction Formula 2.

[0175] 1H NMR (400MHz, DMSO) δ7.69 (s, 2H), 7.54 (d, J = 8.4Hz, 2H), 7.32–7.22 (m, 5H), 7.09 (d, J = 8.2Hz, 2H), 6.82 (t, J = 11.1Hz, 16H), 5.57 (s, 2H), 3.68 (s, 12H). See the attached H NMR spectrum Figure 2 .

[0176] (3) Synthesis of 3,6-bis(4,4'-dimethoxydiphenylamine)-9H-carbazole (Cz-DIDPA):

[0177]

[0178] Benzyl-Cz-DIDPA 1.42g (2mmol), potassium tert-butoxide ((t-Bu)3OK) 2.9g (10eq) and DMSO (dimethyl sulfoxide) 10mL and THF (tetrahydrofuran) 20mL were added to a 100mL double-necked bottle, and the mixture was stirred at room temperature for one night under ventilation. After the reaction, 200mL of deionized water was poured into the reaction system, and the filter cake was collected by suction filtration after stirring for 10min. After vacuum drying, 1.12g of yellow product was obtained with a yield of about 90%. The synthetic route is shown in Reaction Formula 3.

[0179] 1H NMR (400MHz, DMSO) δ11.17 (s, 1H), 7.64 (d, J = 1.7Hz, 2H), 7.39 (d, J = 8.6Hz, 2H), 7.06 (dd, J = 8.6, 2.0Hz, 2H), 6.83 (dd, J = 20.7, 9.1Hz, 16H), 3.69 (s, 12H). See the attached H NMR spectrum Figure 3 .

[0180] Example 1

[0181] Synthesis of 3,5-2CzDIDPA-PY:

[0182]

[0183] Add 115 mg (1 mmol) of 3,5-difluoropyridine, 1.37 g (2.2 eq) of Cz-DIDPA, 1.3 g (4 eq) of cesium carbonate (Cs2CO3), and 10 mL of DMSO (dimethyl sulfoxide) into a 50 mL two-necked flask. Under nitrogen protection, stir the reaction in an oil bath at 150 °C for 48 h. After the reaction is completed, pour the product into deionized water, filter by suction and collect the filter cake to obtain the crude product. After column chromatography separation, 922 mg of yellow product is obtained with a yield of 70%. The synthesis route is shown in Reaction Scheme 4.

[0184] 1H NMR (400 MHz, DMSO) δ 8.93 (d, J = 1.8 Hz, 2H), 8.30 (s, 1H), 7.67 (s, 4H), 7.46 (d, J = 8.8 Hz, 4H), 7.08 (dd, J = 8.8, 1.7 Hz, 4H), 6.80 (dd, J = 20.0, 9.0 Hz, 32H), 3.66 (s, 24H). MALDI-TOF MS: Calcd. For C85H71N7O8 [M / z]: 1317.53; found: 1317.11. The 1H NMR spectrum is shown in the appendix Figure 4 , and the mass spectrum is shown in the appendix Figure 5 .

[0185] Example 2

[0186] Synthesis of 3,5-2CzDIDPA-DMAP:

[0187]

[0188] Specifically, the synthesis method of Example 1 is adopted, and the synthesis route and raw materials are shown in Reaction Scheme 5.

[0189] 1H NMR (400 MHz, DMSO) δ 8.49 (s, 2H), 7.74 (s, 4H), 7.26 (d, J = 8.7 Hz, 4H), 7.09 (d, J = 8.7 Hz, 4H), 6.96–6.72 (m, 32H), 3.69 (s, 24H), 1.88 (s, 6H). MALDI-TOF MS: Calcd. For C87H76N8O8 [M / z]: 1360.57; found: 1360.05. The 1H NMR spectrum is shown in the appendix Figure 6 , and the mass spectrum is shown in the appendix Figure 7 .

[0190] Example 3

[0191] Synthesis of 2,6-2CzDIDPA-DMAP:

[0192]

[0193] Specifically, the synthesis method of Example 1 was adopted, and the synthesis route and raw materials are as shown in Reaction Formula 6.

[0194] 1H NMR (400 MHz, DMSO) δ 7.72 (d, J = 8.9 Hz, 4H), 7.66 (d, J = 2.0 Hz, 4H), 7.04 (dd, J = 8.8, 2.1 Hz, 4H), 6.90 (s, 2H), 6.87 (d, J = 9.0 Hz, 16H), 6.80 (d, J = 9.1 Hz, 16H), 3.68 (s, 24H), 3.15 (s, 6H). MALDI-TOF MS: Calcd. For C87H76N8O8 [M / z]: 1360.57; found: 1360.05. The 1H NMR spectrum is shown in the appendix Figure 8 , and the mass spectrum is shown in the appendix Figure 9 .

[0195]

Preparation of Perovskite Solar Cells

[0196] Example 4

[0197] (1) Preparation of the transparent bottom electrode:

[0198] The glass / ITO was ultrasonically cleaned with detergent, deionized water, absolute ethanol, acetone, and isopropanol for 5 min in sequence, then dried with a high-pressure nitrogen gun, and treated with ultraviolet / ozone for 30 min.

[0199] (2) Preparation of the hole transport layer:

[0200] Nickel oxide with a thickness of 20 nm was magnetron sputtered on the ITO (indium tin oxide) substrate.

[0201] First, clean the magnetron sputtering instrument: clean and polish the inner lining ring of the target with a sandblaster, clean the dust in the cavity with a vacuum cleaner, and finally wipe it clean with absolute ethanol. Fix the glass substrate on the rotatable metal substrate in the cavity with a mask plate, close the chamber door, and adjust the target-substrate distance to 15 cm. Wait until the vacuum degree drops to 9×10 -6 Pa, then the control program starts sputtering. The sputtering process parameters are: power supply: RF, sputtering gas: Ar, target: NiO, sputtering pressure: 45 mTorr, sputtering power: 65 W, substrate temperature: room temperature.

[0202] (3) Preparation of the modification layer

[0203] Weigh 3,5-2CzDIDPA-PY and dissolve it in chlorobenzene. Shake until it is completely dissolved, with a concentration of 0.2 mg / ml. Spin-coat it on the nickel oxide substrate. The rotational speed of the spin coater is 3000 rpm, the acceleration is 1000 rpm, spin-coat for 30 s, and anneal on a hot stage at 100 °C for 10 min to form a modification layer on the upper surface of the hole transport layer.

[0204] (4) Prepare the perovskite light-absorbing layer

[0205] Prepare the perovskite light-absorbing layer by doctor blading. Doctor blade a perovskite precursor solution of 1.31 M FA 0.85 MA 0.1 Cs 0.05 PbI3 with a doctor blade height of 150 μm, a substrate moving speed of 2 mm / s, and an air knife pressure of 0.4 MPa. Then quickly move the substrate to a hot stage for annealing at 100 °C for 1 h to obtain the perovskite light-absorbing layer.

[0206] (5) Prepare the passivation layer

[0207] Weigh EDAI2 (ethyl-1,2-diammonium iodide) and dissolve it in a mixed solvent of IPA (isopropyl alcohol) and CB (CB) (IPA:CB = 2:1). The solution concentration is 1 mg / ml. Spin-coat it on the surface of the perovskite thin film. The rotational speed of the spin coater is 5000 rpm, spin-coat for 30 s, and anneal on a hot stage at 100 °C for 5 min to form a passivation layer on the upper surface of the perovskite light-absorbing layer.

[0208] (6) Prepare the electron transport layer

[0209] By thermal evaporation, sequentially deposit LiF (1 nm, ), C60 (15 nm, ), BCP (6 nm, ) on the passivation layer to form a composite electron transport layer.

[0210] (7) Prepare the top electrode:

[0211] Evaporate the metal electrode Ag (100 nm, -4 ) on the composite electron transport layer under the condition of a vacuum degree of 6.5×10 Pa.

[0212] The perovskite solar cell device structure prepared by the above method is as Figure 10 shown: glass / ITO / NiO x / 3,5-2CzDIDPA-PY / FA 0.85 MA 0.1 Cs 0.05 PbI3 / EDAI2 / LiF,C60,BCP / Ag, with an effective area of 9 mm 2, the data of the photoelectric conversion efficiency can be found in the appendix Figure 11 .

[0213] The test conditions for the photoelectric conversion efficiency are as follows: spectral distribution AM1.5 G, light intensity 1000 W / m 2 , AAA solar simulator (XES-502S + ELS155 type of SAN-EI Corporation, Japan), and the I-V curve is measured with a Keithly 2400 digital source meter.

[0214] Example 5

[0215] Example 5 adopts the preparation method of Example 4, the difference is that the method for preparing the modification layer in step (3) is different, and the preparation of the modification layer is specifically as follows:

[0216] Weigh 3,5-2CzDIDPA-DMAP and dissolve it in chlorobenzene, shake until completely dissolved, with a concentration of 0.1 mg / ml, spin-coat it on the nickel oxide substrate, the speed of the spin coater is 3000 rpm, the acceleration is 1000 rpm, spin-coat for 30 s, and the hot stage is at 90 °C for annealing for 15 min to form a modification layer on the upper surface of the hole transport layer.

[0217] The device structure of the perovskite solar cell prepared by the above method is: glass / ITO / NiO x / 3,5-2CzDIDPA-DMAP / FA 0.85 MA 0.1 Cs 0.05 PbI3 / EDAI2 / LiF,C60,BCP / Ag, and the effective area is 9 mm 2 , the data of the photoelectric conversion efficiency can be found in the appendix Figure 12 , and the test conditions are the same as those in Example 4.

[0218] Example 6

[0219] Example 6 adopts the preparation method of Example 4, the difference is that the method for preparing the modification layer in step (3) is different, and the preparation of the modification layer is specifically as follows:

[0220] Weigh 2,6-2CzDIDPA-DMAP and dissolve it in chlorobenzene, shake until completely dissolved, with a concentration of 0.5 mg / ml, spin-coat it on the nickel oxide substrate, the speed of the spin coater is 3000 rpm, the acceleration is 1000 rpm, spin-coat for 30 s, and the hot stage is at 120 °C for annealing for 5 min to form a modification layer on the upper surface of the hole transport layer.

[0221] The device structure of the perovskite solar cell prepared by the above method is as Figure 10 shown: glass / ITO / NiO x / 2,6-2CzDIDPA-DMAP / FA 0.85 MA0.1 Cs 0.05 PbI3 / EDAI2 / LiF, C60, BCP / Ag, with an active area of 9 mm 2 , and the photoelectric conversion efficiency data can be found in the appendix Figure 13 , and the test conditions are the same as those in Example 4.

[0222] Comparative Example 1

[0223] Comparative Example 1 uses the preparation method of Example 1, except that step (3) is absent, that is, the obtained perovskite solar cell has no modification layer.

[0224] The device structure of the perovskite solar cell prepared by the above method is as Figure 9 shown: Glass / ITO / NiO x / FA 0.85 MA 0.1 Cs 0.05 PbI3 / EDAI2 / LiF, C60, BCP / Ag, with an active area of 9 mm 2 , and the photoelectric conversion efficiency data can be found in the appendix Figure 11 , 12 , 13, and the test conditions are the same as those in Example 4.

[0225] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0226] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A hole transporting material, characterized in that, including at least one of the structures shown in Formula 1: In Formula 1, R is selected from any one of hydrogen, chloro group, bromo group, methoxy group, and dimethylamino group; each Ar is independently selected from any one of hydrogen, straight-chain alkyl groups with 1 to 20 carbon atoms, branched-chain alkyl groups with 1 to 20 carbon atoms, alkoxy groups with 1 to 15 carbon atoms, and groups shown in Formula 2; In Formula 2, R2 is independently selected from any one of hydrogen, straight-chain alkyl groups with 1 to 20 carbon atoms, branched-chain alkyl groups with 1 to 20 carbon atoms, alkoxy groups with 1 to 20 carbon atoms, phenyl group, p-methoxyphenyl group, 4,4'-dimethoxydiphenylamine group, p-tert-butylphenyl group, and carbazolyl group; the dotted line represents the substitution position.

2. The hole transport material according to claim 1, wherein in the shown Formula 1; at least one Ar is selected from the group shown in Formula 2-1, and the remaining Ars are selected from hydrogen: and / or, in the said Formula 2, R2 is selected from 4,4'-dimethoxydiphenylamine group.

3. The hole transporting material according to claim 1 or 2, characterized in that, including at least one of the structures shown in the following Formula I to Formula X: wherein, the dotted line represents the substitution position, and the CZ-DIDPA group has the structure shown in Formula 3:

4. The hole transporting material according to claim 1, wherein including at least one of the structures shown in the following formula: wherein, the dotted line represents the substitution position, and CZ-DIDPA has the structure shown in Formula 3:

5. A method for preparing a hole transport material, characterized in that, including: Performing a substitution reaction on raw material X and raw material Y to prepare a hole transport material; wherein: The raw material X includes the raw material Y includes CZ-DIDPA, and the CZ-DIDPA represents The hole transport material includes wherein R is independently selected from any one of hydrogen, chloro group, bromo group, methoxy group, and dimethylamino group.

6. The method according to claim 5, wherein the preparation method of the CZ-DIDPA includes reacting raw material a with raw material b to obtain intermediate product c; reacting intermediate product c with raw material d to obtain intermediate product e; Performing a dealkylation reaction on intermediate product e to prepare CZ-DIDPA; wherein: The raw material a includes The raw material b includes The intermediate product c includes The raw material d includes The intermediate product e includes 7. The method according to claim 5, wherein the said R is independently selected from any one of hydrogen, methoxy group, and dimethylamino group.

8. A perovskite solar cell, characterized in that, including a hole transport layer, and a modification layer is provided on at least one side of the hole transport layer; The hole transport layer includes a second hole transport material, and the second hole transport material includes NiO x ; the modification layer contains the hole transport material according to any one of claims 1 to 4, or contains the hole transport material obtained by the method according to any one of claims 5 to 7.

9. The perovskite solar cell according to claim 8, wherein The perovskite solar cell further includes a perovskite light-absorbing layer, and the modification layer is located between the hole transport layer and the perovskite light-absorbing layer; the perovskite light-absorbing layer contains a perovskite material, and the perovskite material contains a metal halide perovskite material, and the chemical general formula of the metal halide perovskite material is ABX3; wherein, A represents a monovalent cation; B represents a divalent cation; X represents a monovalent anion.

10. A method for preparing a perovskite solar cell, characterized in that, including: A hole transport layer is formed on the first electrode; the hole transport layer contains a second hole transport material, and the second hole transport material includes NiO x ; forming a modification layer on the hole transport layer, the modification layer contains the hole transport material according to any one of claims 1 to 4, or contains the hole transport material prepared by the method according to any one of claims 5 to 7; forming a perovskite light-absorbing layer on the modification layer; forming an electron transport layer on the perovskite light-absorbing layer; forming a second electrode on the electron transport layer to obtain a perovskite solar cell.

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