Organic semiconductor material, preparation method, application and perovskite solar cell

Abstract

The invention discloses an organic semiconductor material, a preparation method, application and a perovskite solar cell, and belongs to the technical field of organic semiconductor materials and solar cells. An organic semiconductor material having a specially designed structure is provided. By introducing the rigid side arm structure, the conjugate length of the core unit is effectively prolonged, and the carrier transport capability of the hole transport material can be effectively enhanced; particularly, heteroatoms such as oxygen, sulfur and selenium contained in the rigid side arm structure can form a coordination effect with lead atoms in the perovskite, so that multiple effects of passivating defects, namely assisting the crystallization of the perovskite material and the like are achieved; when the perovskite solar cell is prepared, the rigid structure may slow down the aggregation of molecules in a solution and the diffusion rate on a substrate, so that the crystallization process is more uniformly regulated and controlled, the formation of a large-area, high-quality and low-defect-density perovskite thin film is facilitated, pinhole and grain boundary defects are reduced, and the performance of the perovskite solar cell is improved.

Description

Technical Field

[0001] This invention relates to an organic semiconductor material, its preparation method, its application, and a perovskite solar cell, belonging to the technical fields of organic semiconductor materials and solar cells. Background Technology

[0002] Among numerous photovoltaic cell technologies, perovskite solar cells based on organic-inorganic hybrids have become a research hotspot in academia and industry due to their simple fabrication, low cost, and high photoelectric conversion efficiency. They can be fabricated into flexible, fully transparent, and large-area devices through processes such as spin coating, spraying, or printing. Since the fabrication of the first perovskite solar cell in 2009, the photoelectric conversion efficiency of perovskite solar cells has exceeded 26%. Hole transport materials, as an important interface layer between the perovskite crystal and the metal electrode, play a crucial role in promoting hole extraction and transport, as well as suppressing carrier recombination at the interface, significantly improving device performance.

[0003] Since its initial application as a hole transport material in perovskite solar cells in 2009, 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD) has been the most common hole transport material. Spiro-OMeTAD's unique spatial vertical 3D structure gives it excellent thermal stability and photoelectric performance, making it a dominant hole transport material in perovskite solar cells. However, Spiro-OMeTAD suffers from incomplete coverage of the perovskite light-absorbing layer, and the dopant's water absorption affects the performance and stability of perovskite solar cell devices. Therefore, improvements to traditional techniques are necessary. Summary of the Invention

[0004] The purpose of this invention is to provide an organic semiconductor material, a preparation method, an application, and a perovskite solar cell, thereby solving the problem of uneven coverage of the perovskite light-absorbing layer in perovskite solar cells by organic semiconductor materials in the prior art.

[0005] To achieve the above objectives, the present invention employs the following technical solution: In a first aspect, the present invention provides an organic semiconductor material, the structure of which is shown in general formula (I): ; Ar is selected from hydrogen or pyrrole fused ring, and the number of hydrogen atoms is at most three. The dashed line indicates the position and possibility of substitution. The structure of the pyrrole fused ring is as follows: ; R1 is selected from hydrogen, substituted / unsubstituted C1~C1. 12 Alkyl or alkoxy, X is selected from oxygen, sulfur or selenium, and Ar1 is selected from aryl, substituted aryl, heterocyclic aryl or substituted heterocyclic aryl.

[0006] In a second aspect, the present invention provides a method for preparing the organic semiconductor material described in the first aspect, comprising: The organic semiconductor material was prepared by mixing compound M with an indole fused ring, dissolving the mixture in an organic solvent, and heating under reflux in the presence of a catalyst, ligand, and alkaline solution to obtain the desired organic semiconductor material. The synthetic route is shown below: ; In this case, Y is selected from bromine or iodine, and the quantity is 1 to 4.

[0007] Furthermore, the compound M has one of the following structures: .

[0008] Furthermore, the organic solvent is toluene, benzene, chlorobenzene, or o-xylene; The alkaline solution is a potassium carbonate solution, sodium bicarbonate solution, potassium bicarbonate solution, potassium hydroxide solution, sodium hydroxide solution, potassium tert-butoxide solution, or sodium tert-butoxide solution. The catalyst is tetra(triphenylphosphine)palladium, palladium acetate, dichloroditriphenylphosphine palladium, tris(dibenzylideneacetone)dipalladium, or tris(o-tolyl)phosphine; The ligand is triphenylphosphine tetrafluoroborate.

[0009] Furthermore, after preparation, the crude product is purified: the crude product is cooled to room temperature, extracted multiple times with dichloromethane and water, and further purified by column chromatography to obtain the target product.

[0010] Thirdly, the present invention provides applications of the organic semiconductor material described in the first aspect, including: the application of the organic semiconductor material in the preparation of hole transport materials.

[0011] Fourthly, the present invention provides a perovskite solar cell, comprising, from top to bottom, a second electrode, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, and a first electrode, wherein the hole transport layer is made of the organic semiconductor material described in the first aspect.

[0012] Fifthly, the present invention provides a method for preparing the perovskite solar cell described in the fourth aspect, comprising: Prepare the first electrode; An electron transport layer is formed on the surface of the first electrode; A perovskite light-absorbing layer is formed on the surface of the electron transport layer away from the first electrode; A hole transport layer is formed on the surface of the perovskite light-absorbing layer away from the electron transport layer; the hole transport layer is made of the organic semiconductor material. A second electrode is formed on the surface of the hole transport layer away from the perovskite light-absorbing layer to obtain a perovskite solar cell.

[0013] Furthermore, the hole transport layer is prepared by the following method: the organic semiconductor material is made into an organic semiconductor material solution, and the organic semiconductor material solution is spin-coated onto the surface of the perovskite light-absorbing layer away from the electron transport layer by a solution spin-coating method to form a hole transport layer.

[0014] Furthermore, the first electrode is a transparent conductive electrode, selected from at least one of indium tin oxide, indium zinc oxide, tungsten-doped indium oxide, and aluminum-doped zinc oxide; The electron transport layer is at least one of tin oxide, titanium dioxide, and zinc oxide; The perovskite light-absorbing layer is an ABX3 type perovskite material, wherein A is at least one of cesium ion, rubidium ion, potassium ion, methylamine ion, formamidinium ion, methylenediamine ion, benzylamidinium cation, and guanidine cation; B is at least one of divalent lead ion and divalent tin ion; and X is at least one of fluoride ion, chloride ion, bromide ion, iodide ion, thiocyanate ion, tetrafluoroborate ion, hexafluorophosphate ion, formate ion, and acetate ion. The second electrode is selected from at least one of gold, silver, aluminum and copper.

[0015] Compared with the prior art, the beneficial effects achieved by the present invention are: This invention provides an organic semiconductor material, a preparation method, an application, and a perovskite solar cell. The structure of the organic semiconductor material reveals the introduction of a rigid side-arm structure, effectively extending the conjugate length of the core unit. When the organic semiconductor material is used as the hole transport material in the hole transport layer of a perovskite solar cell, it effectively enhances the carrier transport capability of the hole transport material. In particular, the heteroatoms such as oxygen, sulfur, and selenium contained in the rigid side-arm structure can form coordination interactions with lead atoms in the perovskite, playing multiple roles such as passivating defects and assisting in the crystallization of the perovskite material. During the preparation of perovskite solar cells, the rigid structure may slow down the aggregation of molecules in solution and the diffusion rate on the substrate, thereby more uniformly controlling the crystallization process. This helps to form a large-area, high-quality perovskite thin film with low defect density, reducing pinholes and grain boundary defects, and thus improving the performance of the perovskite solar cell. In the molecular structure of organic semiconductor materials, the heteroatom X in the side arm group can form a coordination bond Pb-X with the lead atom in perovskite, improving interfacial contact. As a hole transport material, it is used in formal perovskite solar cell devices, and the photoelectric conversion efficiency is above 20%. Attached Figure Description

[0016] Figure 1 These are the electrochemical spectra of organic semiconductor materials T1, T2, T3 and T4 provided by the present invention; wherein, (a) corresponds to T1, (b) corresponds to T2, (c) corresponds to T3 and (d) corresponds to T4; Figure 2 These are the steady-state fluorescence spectra of organic semiconductor materials T1, T2, T3, and T4 provided by this invention; Figure 3 This is a schematic diagram of the structure of the perovskite solar cell provided by the present invention; Figure 4 This is the general structural formula of the organic semiconductor material provided by the present invention. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to illustrate the technical solution of the present invention more clearly, and should not be used to limit the scope of protection of the present invention.

[0018] This invention provides, for example Figure 4 The organic semiconductor material shown is described below. Examples 1 to 4 are used to prepare organic semiconductor materials T1, T2, T3 and T4 with specific structures that conform to the general formula.

[0019] Example 1

[0020] This embodiment first prepares the organic semiconductor material T1, specifically including the following steps: Under a nitrogen atmosphere, in a dry 250 mL double-necked flask, 2-bromo-9,9'-spirodifluorene (3.94 g, 10 mmol), 4-hydro-thienophenoindole (1.73 g, 10 mmol), cesium carbonate (25.41 g, 78 mmol), 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl (0.3 g, 0.5 mmol), and palladium acetate (0.06 g, 0.25 mmol) were added sequentially, followed by 50 mL of xylene. The mixture was refluxed at 140 °C for 12 h. After the reaction was complete, the mixture was cooled to room temperature, extracted with dichloromethane and water, dried, and the solvent was removed by vacuum distillation. The resulting product was purified by silica gel column chromatography and recrystallized from a toluene / petroleum ether system to give T1 (4.28 g, 88% yield). The electrochemical and steady-state fluorescence spectra of T1 were measured, and the results are shown below. Figure 1 and Figure 2 As shown.

[0021] Test T1 1H NMR spectrum 1 H NMR (test conditions: 400 MHz, DMSO-) d 6), the result is described as: δ8.27 (d, J =8.2 Hz, 1H), 8.06 (d, J =8.2 Hz, 1H), 7.97 (d, J =8.2 Hz, 2H), 7.71 (d, J =7.0 Hz, 2H), 7.69–7.51 (m, 4H), 7.28 (m, 3H), 7.25–7.16 (m, 1H), 7.14–7.05(m, 2H), 6.95–6.83 (m, 3H), 6.78 (d, J =5.7 Hz, 2H). Where δ represents the chemical shift and d represents a doublet. J It is the coupling constant, and 1H indicates that the signal corresponds to a hydrogen atom.

[0022] The structural formula for T1 is shown below: .

[0023] Perovskite solar cells fabricated based on organic semiconductor material T1 include: Step 1: The ITO conductive glass substrate (indium tin oxide) is ultrasonically cleaned sequentially with deionized water, acetone, and ethanol for 15 minutes each. After drying with nitrogen, it is treated with ultraviolet ozone for 30 minutes and then set aside for later use. The material obtained in Step 1 is the first electrode.

[0024] Step 2: Dilute 15% SnO2 colloidal dispersion with deionized water at a volume ratio of 1:2, spin coat at 5000 rpm for 30 seconds (acceleration 1000 rpm / s) onto the surface of ITO conductive glass substrate, and anneal at 150℃ for 30 minutes to form an electron transport layer.

[0025] Step 3: Dissolve CsI (0.085 mol / L), MABr (0.25 mol / L), FAI (1.3 mol / L), PbI2 (1.5 mol / L), and PbBr2 (0.25 mol / L) in a mixed solvent (DMF:DMSO=4:1, v / v), and stir overnight in the dark (≥12 hours) to prepare a perovskite precursor solution. Filter the solution through a 0.22 μm filter, accelerate it from 1000 rpm / s to 6000 rpm, spin-coat it onto the surface of the electron transport layer for 30 s, add 100 μL of the antisolvent ethyl acetate at 25 s, continue for 10 s, anneal at 100℃ for 40 minutes, and then cool to room temperature to form a perovskite light-absorbing layer.

[0026] Step 4: Dissolve organic semiconductor material T1 (20 mg / mL) in chlorobenzene, take 35 μL of it, spin-coat it onto the surface of the perovskite light-absorbing layer at 3000 rpm / s for 30 s to form a hole transport layer.

[0027] Step 5: Transfer the device to the vacuum evaporation chamber and pass it through a vacuum (vacuum degree: 5×10). -4 A second electrode is formed by depositing a gold electrode (100 nm) on the surface of the hole transport layer using vapor deposition (Pa).

[0028] Example 2

[0029] This embodiment first prepares the organic semiconductor material T2, specifically including the following steps: Under a nitrogen atmosphere, in a dry 250 mL double-necked flask, 2,7-dibromo-9,9'-spirodifluorene (4.73 g, 10 mmol), 4-hydro-thienophenoindole (3.46 g, 20 mmol), cesium carbonate (25.41 g, 78 mmol), 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl (0.3 g, 0.5 mmol), and palladium acetate (0.06 g, 0.25 mmol) were added sequentially, followed by 60 mL of xylene. The mixture was refluxed at 140 °C for 16 h. After the reaction, the mixture was cooled to room temperature, extracted with dichloromethane and water, dried, and the solvent was removed by vacuum distillation. The resulting product was purified by silica gel column chromatography and recrystallized from a toluene / petroleum ether system to give T2 (4.54 g, 69% yield). The electrochemical and steady-state fluorescence spectra of T2 were measured, and the results are shown below. Figure 1 and Figure 2 As shown.

[0030] Test T2 1H NMR spectrum 1 H NMR (test conditions: 400 MHz, DMSO-) d 6), the result is described as: δ8.36 (dd, J =34.2, 8.2 Hz, 2H), 8.06 (dd, J =33.0, 8.2 Hz, 2H), 7.81 (dd, J =14.1,8.5 Hz, 4H), 7.72–7.56 (m, 4H), 7.30 (q, J =6.9, 5.3 Hz, 2H), 7.27 (m, 2H),7.22–7.11 (m, 4H), 7.05 (d, J =20.1 Hz, 2H), 6.99–6.82 (m, 4H). Where δ represents the chemical shift, and d indicates a doublet. J It is the coupling constant, and 1H indicates that the signal corresponds to a hydrogen atom.

[0031] The structural formula of T2 is shown below: .

[0032] Perovskite solar cells were prepared based on organic semiconductor material T2. The process of preparing perovskite solar cells was basically the same as in Example 1, except that organic semiconductor material T1 was replaced with organic semiconductor material T2 (20 mg / mL).

[0033] Example 3

[0034] This embodiment first prepares the organic semiconductor material T3, specifically including the following steps: Under a nitrogen atmosphere, in a dry 250 mL double-necked flask, 2,2',7-tribromo-9,9'-spirodifluorene (5.52 g, 10 mmol), 2-methoxy-4-hydro-thienoindole (6.09 g, 30 mmol), cesium carbonate (25.41 g, 78 mmol), 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl (0.3 g, 0.5 mmol), and palladium acetate (0.06 g, 0.25 mmol) were added sequentially, followed by 80 mL of xylene. The mixture was refluxed at 140 °C for 20 h. After the reaction, the mixture was cooled to room temperature, extracted with dichloromethane and water, dried, and the solvent was removed by vacuum distillation. The resulting product was purified by silica gel column chromatography and recrystallized from a toluene / petroleum ether system to obtain T3 (5.64 g, 62% yield). The electrochemical and steady-state fluorescence spectra of T3 were measured, and the results are shown below. Figure 1 and Figure 2 As shown.

[0035] Testing the proton NMR spectrum of T3 1 H NMR (test conditions: 400 MHz, DMSO-) d 6), the result is described as: δ8.39 (d, J =8.2 Hz, 2H), 8.32 (d, J =8.1 Hz, 1H), 8.09 (d, J =8.2 Hz, 1H), 7.79 (dd, J =14.9, 6.7 Hz, 6H), 7.72–7.61 (m, 4H), 7.27 (m, 1H), 7.23–7.09 (m, 8H), 7.06 (s, 2H), 6.93 (d, J =5.2 Hz, 3H), 3.81 Hz, 9H. Where δ represents the chemical shift, and d represents a doublet. J It is the coupling constant, and 1H indicates that the signal corresponds to a hydrogen atom.

[0036] The structural formula of T3 is shown below: .

[0037] Perovskite solar cells were prepared based on organic semiconductor material T3. The process of preparing perovskite solar cells was basically the same as in Example 1, except that organic semiconductor material T1 was replaced with organic semiconductor material T3 (32 mg / mL).

[0038] Example 4

[0039] This embodiment first prepares the organic semiconductor material T4, specifically including the following steps: Under a nitrogen atmosphere, in a dry 250 mL double-necked flask, 2,2',7,7'-tetrabromo-9,9'-spirodifluorene (6.32 g, 10 mmol), 2-methoxy-4-hydro-thienoindole (8.53 g, 42 mmol), cesium carbonate (25.41 g, 78 mmol), 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl (0.3 g, 0.5 mmol), and palladium acetate (0.06 g, 0.25 mmol) were added sequentially, followed by 90 mL of xylene. The mixture was refluxed at 140 °C for 36 h. After the reaction, the mixture was cooled to room temperature, extracted with dichloromethane and water, dried, and the solvent was removed by vacuum distillation. The resulting product was purified by silica gel column chromatography and recrystallized from a toluene / petroleum ether system to give T4 (4.20 g, 37% yield). The electrochemical and steady-state fluorescence spectra of T4 were measured, and the results are shown below. Figure 1 and Figure 2 As shown.

[0040] Testing the proton NMR spectrum of T4 1 H NMR (test conditions: 400 MHz, DMSO-) d 6), the result is described as: δ8.37 (d, J =8.2 Hz, 4H), 7.85–7.77 (m, 8H), 7.66 (d, J =5.2 Hz, 4H), 7.36 (dd, J =6.2, 3.0 Hz, 4H), 7.22–7.14 (m, 8H), 6.96 (d, J =5.2 Hz, 4H), 3.78 Hz, 12H. Where δ represents the chemical shift, and d indicates a doublet. J It is the coupling constant, and 1H indicates that the signal corresponds to a hydrogen atom.

[0041] The structural formula for T4 is shown below: .

[0042] Perovskite solar cells were prepared based on organic semiconductor material T4. The process of preparing perovskite solar cells was basically the same as in Example 1, except that organic semiconductor material T1 was replaced with organic semiconductor material T4 (25 mg / mL).

[0043] The open-circuit voltage of the perovskite solar cells prepared in Examples 1 to 4 was measured. V oc, short-circuit current density JThe open-circuit voltage (SC), fill factor (FF), and photoelectric conversion efficiency (PCE) were tested (under AM 1.5G standard sunlight, light intensity 100mW / cm²), and stability was tested in an air environment (humidity: 30%~50%) for 1000 hours. The experimental results are detailed in Table 1. The open-circuit voltage, short-circuit current density, fill factor, and photoelectric conversion efficiency were obtained through IV curve testing.

[0044] Table 1 - Test Results

[0045] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An organic semiconductor material, characterized in that, The structure of the organic semiconductor material is shown in general formula (I): ； Ar is selected from hydrogen or pyrrole fused ring, and the number of hydrogen atoms is at most three. The dashed line indicates the position and possibility of substitution. The structure of the pyrrole fused ring is as follows: ; R1 is selected from hydrogen, substituted / unsubstituted C1~C1. 12 Alkyl or alkoxy, X is selected from oxygen, sulfur or selenium, and Ar1 is selected from aryl, substituted aryl, heterocyclic aryl or substituted heterocyclic aryl.

2. The method for preparing the organic semiconductor material according to claim 1, characterized in that, include: The organic semiconductor material was prepared by mixing compound M with an indole fused ring, dissolving the mixture in an organic solvent, and heating under reflux in the presence of a catalyst, ligand, and alkaline solution to obtain the desired organic semiconductor material. The synthetic route is shown below: ； In this case, Y is selected from bromine or iodine, and the quantity is 1 to 4.

3. The preparation method according to claim 2, characterized in that, The compound M has one of the following structures: 。 4. The preparation method according to claim 2, characterized in that, The organic solvent is toluene, benzene, chlorobenzene, or o-xylene; The alkaline solution is a potassium carbonate solution, sodium bicarbonate solution, potassium bicarbonate solution, potassium hydroxide solution, sodium hydroxide solution, potassium tert-butoxide solution, or sodium tert-butoxide solution. The catalyst is tetra(triphenylphosphine)palladium, palladium acetate, dichloroditriphenylphosphine palladium, tris(dibenzylideneacetone)dipalladium, or tris(o-tolyl)phosphine; The ligand is triphenylphosphine tetrafluoroborate.

5. The preparation method according to claim 2, characterized in that, After preparation, the crude product is purified: the crude product is cooled to room temperature, extracted multiple times with dichloromethane and water, and further purified by column chromatography to obtain the target product.

6. The application of the organic semiconductor material according to claim 1, characterized in that, include: The application of the organic semiconductor material in the preparation of hole transport materials.

7. A perovskite solar cell, characterized in that, It includes, from top to bottom, a second electrode, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, and a first electrode, wherein the hole transport layer is made of the organic semiconductor material as described in claim 1.

8. The method for preparing the perovskite solar cell according to claim 7, characterized in that, include: Prepare the first electrode; An electron transport layer is formed on the surface of the first electrode; A perovskite light-absorbing layer is formed on the surface of the electron transport layer away from the first electrode; A hole transport layer is formed on the surface of the perovskite light-absorbing layer away from the electron transport layer; the hole transport layer is made of the organic semiconductor material. A second electrode is formed on the surface of the hole transport layer away from the perovskite light-absorbing layer to obtain a perovskite solar cell.

9. The preparation method according to claim 8, characterized in that, The hole transport layer is prepared by the following method: the organic semiconductor material is made into an organic semiconductor material solution, and the organic semiconductor material solution is spin-coated onto the surface of the perovskite light-absorbing layer away from the electron transport layer by a solution spin-coating method to form a hole transport layer.

10. The preparation method according to claim 8, characterized in that, The first electrode is a transparent conductive electrode, selected from at least one of indium tin oxide, indium zinc oxide, tungsten-doped indium oxide, and aluminum-doped zinc oxide; The electron transport layer is at least one of tin oxide, titanium dioxide, and zinc oxide; The perovskite light-absorbing layer is an ABX3 type perovskite material, wherein A is at least one of cesium ion, rubidium ion, potassium ion, methylamine ion, formamidinium ion, methylenediamine ion, benzylamidinium cation, and guanidine cation; B is at least one of divalent lead ion and divalent tin ion; and X is at least one of fluoride ion, chloride ion, bromide ion, iodide ion, thiocyanate ion, tetrafluoroborate ion, hexafluorophosphate ion, formate ion, and acetate ion. The second electrode is selected from at least one of gold, silver, aluminum and copper.

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