Thienoindole self-assembled small molecule compound as well as preparation method and application thereof

Abstract

The invention discloses a thienoindole self-assembled small molecule compound and a preparation method and application thereof, and belongs to the technical field of organic photoelectric materials, the structure of the thienoindole self-assembled small molecule compound is shown as a formula (1): # imgabs0 # formula (1), and thienoindole serves as a core unit; a is an anchoring group including phosphoric acid, carboxylic acid or sulfonic acid; x is a substituent group and comprises hydrogen, bromine or iodine; and n is an integer between 2 and 8. The material has good solubility and appropriate molecular energy level, functional groups are easily introduced into the molecular structure, the solubility, hole transport property, molecular energy level and the like of the material are improved, heteroatoms can form coordination with perovskite components, and crystallization and interface contact of perovskite are facilitated.

Description

Technical Field

[0001] The invention relates to a thienoindole self-assembly small molecule compound and a preparation method and application thereof, belonging to the technical field of organic photoelectric materials. Background Art

[0002] Solar energy is a rapidly developing clean energy that can replace traditional fossil fuels. Its development and utilization is an important way to achieve sustainable development of human society and has broad market prospects. Solar cells that convert solar energy into electrical energy have attracted widespread attention from academia and industry in various countries. Photovoltaic technology has been continuously developing and innovating over the past few decades. Among the third-generation photovoltaic technologies, the development of perovskite solar cells (PSCs) has attracted the most attention.

[0003] In efficient conventional PSCs, hole transport materials (HTMs), as an important interfacial layer between perovskite crystals and metal electrodes, play a very important role in promoting the extraction and transport of holes and inhibiting carrier recombination at the interface between perovskite and HTMs, which can significantly improve the performance of the device.

[0004] Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and polytriarylamine (PTAA) are two typical polymer hole transport materials for trans-perovskite solar cells. PEDOT:PSS will corrode the electrode due to its own acidity, and its hygroscopicity will affect the stability of perovskite solar cell devices. In addition, the work function between it and perovskite greatly limits the efficiency of the battery device. On the contrary, although the efficiency of PTAA-based pin perovskite solar cells is high, it is not only very expensive, but also requires additional chemical doping to obtain high-efficiency device performance. Furthermore, its hydrophobicity also affects the quality of perovskite films, especially for roll-to-roll printing processes. In summary, it is difficult for existing hole transport materials to improve the overall performance of perovskite solar cells. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a thienoindole self-assembled small molecule compound and its preparation method and application. This type of material has good solubility, is easy to introduce functional groups, improves the hole transportability and molecular energy level of the material, is beneficial to the crystallization and interface contact of perovskite, and can improve the overall performance of perovskite solar cells.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] In the first aspect, the present invention provides a thienoindole self-assembling small molecule compound, the structure of the thienoindole self-assembling small molecule compound is shown in formula (1):

[0008]

[0009] Formula (1)

[0010] Among them, thienoindole is used as a core unit; A is an anchoring group, including phosphoric acid, carboxylic acid or sulfonic acid; X is a substituent group, including hydrogen, bromine or iodine; and n is an integer between 2 and 8.

[0011] In a second aspect, the present invention provides a method for preparing a thienoindole self-assembly small molecule compound, and the reaction equation is as follows:

[0012] The following steps are involved:

[0013] Step a, dissolving a thienoindole derivative in an organic solvent, adding a base and a nucleophilic reagent, heating to reflux, then adding a dihalogenated hydrocarbon to carry out an alkylation reaction, and performing extraction, column chromatography separation and purification to obtain a haloalkyl substituted thienoindole derivative;

[0014] Step b, adding a nucleophilic agent to a haloalkyl substituted thienoindole derivative, heating under reflux for a period of time in an inert gas, stopping the reaction to room temperature, and removing excess nucleophilic agent by distillation to obtain an intermediate product a;

[0015] Step c, dissolving the intermediate product a in an organic solvent, slowly adding a halogenated silylating agent dropwise, reacting at room temperature, and removing the organic solvent by rotary evaporation to obtain an intermediate product b;

[0016] Step d, dissolving the intermediate product b in an organic solvent, stirring at room temperature, adding water until the solution becomes turbid, continuing to stir, filtering, washing the filter cake with water, recrystallizing with an organic solvent, and filtering again to obtain a thienoindole self-assembled small molecule compound.

[0017] In step a, the organic solvent is any one of tetrahydrofuran, toluene, chlorobenzene, and N,N-dimethylformamide; the base is any one of potassium hydroxide, sodium hydroxide, and barium hydroxide; the nucleophilic reagent is potassium iodide; and the dihalogenated hydrocarbon is any one of 1,2-dibromoethane, 1,3-dibromopropane, 1,4-dibromobutane, 1,5-dibromopentane, 1,6-dibromohexane, 1,2-dibromoheptane, and 1,6-dibromooctane.

[0018] In step a, the heating reflux temperature is 70 to 100 o C.

[0019] In step b, the nucleophilic reagent is triethyl phosphite; and the inert gas is either nitrogen or argon.

[0020] In step b, the heating temperature is 150-160o C, time is 24h.

[0021] In step c, the organic solvent is any one of N,N-dimethylformamide and 1,4-dioxane; the halogenated silylating agent is any one of trimethylbromosilane, trimethylchlorosilane, tetramethyldisilane and tetramethyltetrachlorosilane.

[0022] In step d, the organic solvent is any one of methanol, ethanol, propanol, and propylene glycol; the water is deionized water; and the organic solvent is tetrahydrofuran and petroleum ether.

[0023] In a third aspect, the present invention provides the use of thienoindole self-assembled small molecule compounds in trans-perovskite solar cells.

[0024] The device structure of the inverted perovskite solar cell is: ITO / hole transport material / MAPbI3 / PCBM / Ag, and the hole transport material adopts the thienoindole self-assembled small molecule compound.

[0025] Beneficial effects of the present invention: The present invention provides a thienyl indole self-assembly small molecule compound and its preparation method and application. The preparation process is simple, easy to operate, and low in cost. With thienyl indole as the core unit, the solubility of hole transport material molecules in organic solvents can be effectively improved; suitable molecular energy levels can easily introduce functional groups in the molecular structure to improve the solubility, hole transport, molecular energy level, etc. of the material; the asymmetry of the molecular structure and the presence of heteroatoms are conducive to improving the quality of the film, the extraction and transmission capacity of holes, and the presence of heteroatoms can form a coordination effect with the perovskite component, which is conducive to the crystallization and interface contact of the perovskite; the introduction of atoms of different numbers of halogens is conducive to the management of the interface dipole moment; in addition, the introduction of anchoring groups of different lengths can realize the self-assembly behavior regulation of the material. In summary, the thienyl indole self-assembly small molecule hole transport material involved in the present invention has potential application value in optoelectronic devices such as perovskite solar cells, organic solar cells or organic field effect transistors. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is the hydrogen spectrum of the self-assembled small molecule compound PATi of the present invention;

[0027] Figure 2 It is the hydrogen spectrum of the self-assembled small molecule compound Br-PATi of the present invention;

[0028] Figure 3 It is the hydrogen spectrum of the self-assembled small molecule compound 2Br-PATi of the present invention;

[0029] Figure 4It is the ultraviolet visible absorption (Uv-vis) spectrum of the self-assembled small molecule compound PATi solution of the present invention;

[0030] Figure 5 It is the ultraviolet visible absorption (Uv-vis) spectrum of the self-assembled small molecule compound Br-PATi solution of the present invention;

[0031] Figure 6 It is the ultraviolet visible absorption (Uv-vis) spectrum of the self-assembled small molecule compound 2Br-PATi solution of the present invention;

[0032] Figure 7 1 is a cyclic voltammetry (CV) curve of the self-assembled small molecule compound PATi of the present invention;

[0033] Figure 8 1 is a cyclic voltammetry (CV) curve of the self-assembled small molecule compound Br-PATi of the present invention;

[0034] Fig. 9 The cyclic voltammetry (CV) curve of the self-assembled small molecule compound 2Br-PATi of the present invention;

[0035] Fig.10 It is the general structural formula diagram of the self-assembling small molecule compound of the present invention. DETAILED DESCRIPTION

[0036] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the protection scope of the present invention.

[0037] Example 1

[0038] The present invention discloses a method for preparing a thienoindole self-assembly small molecule compound, and the preparation process is mainly as follows:

[0039] , where the final product has the following general structure: Fig.10 As shown, A is HPO3, X is H, and n is 4.

[0040] The present invention mainly comprises the following steps:

[0041] Step 1: In a 100 ml two-necked flask, I-1 (5 g, 0.029 mol) was dissolved in an organic solvent THF (50 ml), and KOH (8.14 g, 0.145 mol), KI (0.48 g, 2.9 mmol) and 75 oC was heated to reflux, 1, 4-dibromobutane (9.42 g, 0.044 mol) was injected into the reaction flask, and after 24 hours of reaction, it was extracted with dichloromethane and water, the organic layer was dried with anhydrous sodium sulfate, and the organic solvent was removed by rotary evaporation. With petroleum ether as the eluent, column chromatography was performed to obtain a light yellow liquid halogenated alkyl substituted thienoindole derivative I-2 (3.6 g, yield 40%), the specific structure of which is shown below.

[0042]

[0043] Step 2: In a 100 ml two-necked flask, add the haloalkyl substituted thienoindole derivative I-2 (3.6 g, 0.012 mol) and triethyl phosphite (30 ml) and, under nitrogen atmosphere, 158 o C was heated under reflux. After 24 hours, the reaction was stopped and the excess triethyl phosphite was removed by distillation under reduced pressure to obtain a light yellow oily liquid as the intermediate product a.

[0044] Step 3: dissolve the light yellow oily liquid in an organic solvent 1, 4-dioxane (30 ml), slowly add trimethylsilyl bromide (17.88 g, 0.117 mol) dropwise using a disposable syringe at room temperature, stir for 12 hours, stop the reaction, remove 1, 4-dioxane by rotary evaporation, and the obtained white solid is the intermediate product b.

[0045] Step 4: Dissolve the white solid in an organic solvent, methanol (30 ml), stir, and after 3 hours, add deionized water until the solution becomes turbid, continue stirring for 12 hours, stop the reaction, filter, and wash the filter cake with deionized water. The washed filter cake is recrystallized with tetrahydrofuran and petroleum ether, filtered, and a white-gray powder is obtained, which is a self-assembled small molecule compound PATi (2.5 g, yield 69%), and the specific structure is shown below.

[0046] .

[0047] Example 2

[0048] The present invention discloses a method for preparing a thienoindole self-assembly small molecule compound, and the preparation process is mainly as follows:

[0049] , where the final product has the following general structure: Fig.10 As shown, A is HPO3, X on the benzene ring structure is Br, X on the thiophene structure is H, and n is 4.

[0050] The present invention mainly comprises the following steps:

[0051] Step 1: In a 100 ml two-necked flask, I-1 (3.4 g, 0.014 mol ) was dissolved in an organic solvent, THF (30 ml), and KOH (3.79 g, 0.068 mol ), KI (0.22 g, 1.4 mmol ) and 75 o C was heated to reflux, 1, 4-dibromobutane (4.39 g, 0.020 mol) was injected into the reaction flask, and after 24 hours of reaction, it was extracted with dichloromethane and water, the organic layer was dried with anhydrous sodium sulfate, and the organic solvent was removed by rotary evaporation. With petroleum ether as the eluent, column chromatography was performed to obtain a light yellow liquid halogenated alkyl substituted thienoindole derivative I-2 (2 g, yield 38%), the specific structure of which is shown below.

[0052]

[0053] Step 2: In a 100 ml two-necked flask, add a haloalkyl substituted thienoindole derivative I-2 (2 g, 5.2 mmol) and triethyl phosphite (20 ml). Heat under reflux at 158 ​​°C under a nitrogen atmosphere. After 24 hours, stop the reaction and remove the excess triethyl phosphite by distillation under reduced pressure to obtain a light yellow oily liquid as intermediate a.

[0054] Step 3: dissolve the light yellow oily liquid in an organic solvent 1, 4-dioxane (20 ml), slowly add trimethylsilyl bromide (7.91 g, 0.052 mol) dropwise with a disposable syringe at room temperature, stir for 12 hours, stop the reaction, remove 1, 4-dioxane by rotary evaporation, and the obtained white solid is the intermediate product b.

[0055] Step 4: Dissolve the white solid in an organic solvent, methanol (20 ml), stir, and after 3 hours, add deionized water until the solution becomes turbid, continue stirring for 12 hours, stop the reaction, filter, and wash the filter cake with deionized water. The washed filter cake is recrystallized with tetrahydrofuran and petroleum ether, filtered, and a white-gray powder is obtained, which is a self-assembled small molecule hole transport material Br-PATi (1.4 g, yield 70%), and the specific structure is shown below.

[0056] .

[0057] Example 3

[0058] The present invention discloses a method for preparing a thienoindole self-assembly small molecule compound, and the preparation process is mainly as follows:

[0059] , where the final product has the following general structure: Fig.10 As shown, A is HPO3, X is Br, and n is 4.

[0060] The present invention mainly comprises the following steps:

[0061] Step 1: In a 100 ml two-necked flask, I-1 (3.31 g, 0.01 0.014 mol ) was dissolved in an organic solvent THF (30 ml), and KOH (2.8 g, 0.05 mol ) and KI (0.17 g, 0.001 1.4 mmol ) were added in sequence. o C was heated to reflux, 1, 4-dibromobutane (3.08 g, 0.014 mol) was injected into the reaction flask, and after 24 hours of reaction, it was extracted with dichloromethane and water, the organic layer was dried with anhydrous sodium sulfate, and the organic solvent was removed by rotary evaporation. With petroleum ether as the eluent, column chromatography was performed to obtain a light yellow liquid halogenated alkyl substituted thienoindole derivative I-2 (1.96 g, yield 42%), the specific structure of which is shown below.

[0062]

[0063] Step 2, in a 100 ml two-necked flask, add the haloalkyl substituted thienoindole derivative I-2 (3 g, 6.4 mmol) and triethyl phosphite (30 ml), heat under reflux at 158 ​​°C under nitrogen atmosphere, stop the reaction after 24 hours, and remove the excess triethyl phosphite by distillation under reduced pressure to obtain a light yellow oily liquid as intermediate a.

[0064] Step 3: dissolve the light yellow oily liquid in an organic solvent, 1, 4-dioxane (30 ml), slowly add trimethylsilyl bromide (9.85 g, 0.064 mol) using a disposable syringe at room temperature, stir for 12 hours, stop the reaction, remove 1, 4-dioxane by rotary evaporation, and the obtained white solid is the intermediate product b.

[0065] Step 4: Dissolve the white solid in an organic solvent, methanol (30 ml), stir, and after 3 hours, add deionized water until the solution becomes turbid, continue stirring for 12 hours, stop the reaction, filter, and wash the filter cake with deionized water. The washed filter cake is recrystallized with tetrahydrofuran and petroleum ether, filtered, and a white-gray powder is obtained, which is a self-assembled small molecule hole transport material 2Br-PATi (2.2 g, yield 73%), and the specific structure is shown below.

[0066] .

[0067] Figures 1 to 3They are hydrogen spectra of three self-assembled small molecule compounds PATi, Br-PATi and 2Br-PATi of the present invention. It can be seen from the figures that the corresponding products can be prepared by adopting the preparation method of the present invention. Figures 4 to 6 They are respectively the ultraviolet visible absorption (Uv-vis) spectra of the three self-assembled small molecule compounds PATi, Br-PATi and 2Br-PATi solutions of the present invention. It can be seen from the figures that the three materials have no absorption in the near-infrared light region and will not affect the absorption of sunlight by the perovskite material. Figures 7 to 9 They are the cyclic voltammetry (CV) curves of the three self-assembled small molecule compounds PATi, Br-PATi and 2Br-PATi of the present invention. From the figure, it can be calculated that the corresponding HOMO energy levels of the three materials are -5.69 eV, -5.72 eV and -5.65 eV, which can achieve a good match with the VB energy level of the perovskite material used in this chapter (-5.70 eV).

[0068] The three self-assembled small molecule compounds PATi, Br-PATi and 2Br-PATi of the present invention were respectively applied to perovskite solar cell devices, and the performance parameters of the solar cell devices were obtained through testing, as shown in Table 1. It can be seen from the table that the thienoindole self-assembled small molecule compounds prepared by the present invention are used as hole transport materials in the device structure of the trans-perovskite solar cell, which can significantly improve the overall performance of the perovskite solar cell.

[0069] Table 1 Performance parameters of perovskite solar cell devices

[0070]

[0071] The thienoindole self-assembled small molecule hole transport material involved in the present invention has potential application value in photoelectric devices such as perovskite solar cells, organic solar cells or organic field effect transistors.

[0072] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A thienoindole self-assembly small molecule compound, characterized in that: The structure of the thienoindole self-assembly small molecule compound is shown in formula (1): ， Formula (1) Among them, thienoindole is used as a core unit; A is an anchoring group, including phosphoric acid, carboxylic acid or sulfonic acid; X is a substituent group, including hydrogen, bromine or iodine; and n is an integer between 2 and 8.

2. The method for preparing the thienoindole self-assembly small molecule compound according to claim 1, characterized in that: The following steps are involved: Step a, dissolving a thienoindole derivative in an organic solvent, adding a base and a nucleophilic reagent, heating to reflux, then adding a dihalogenated hydrocarbon to carry out an alkylation reaction, and performing extraction, column chromatography separation and purification to obtain a haloalkyl substituted thienoindole derivative; Step b, adding a nucleophilic agent to a haloalkyl substituted thienoindole derivative, heating under reflux for a period of time in an inert gas, stopping the reaction to room temperature, and removing excess nucleophilic agent by distillation to obtain an intermediate product a; Step c, dissolving the intermediate product a in an organic solvent, slowly adding a halogenated silylating agent dropwise, reacting at room temperature, and removing the organic solvent by rotary evaporation to obtain an intermediate product b; Step d, dissolving the intermediate product b in an organic solvent, stirring at room temperature, adding water until the solution becomes turbid, continuing to stir, filtering, washing the filter cake with water, recrystallizing with an organic solvent, and filtering again to obtain a thienoindole self-assembled small molecule compound.

3. The method for preparing the thienoindole self-assembly small molecule compound according to claim 2, characterized in that: In step a, the organic solvent is any one of tetrahydrofuran, toluene, chlorobenzene, and N,N-dimethylformamide; the base is any one of potassium hydroxide, sodium hydroxide, and barium hydroxide; the nucleophilic reagent is potassium iodide; and the dihalogenated hydrocarbon is any one of 1,2-dibromoethane, 1,3-dibromopropane, 1,4-dibromobutane, 1,5-dibromopentane, 1,6-dibromohexane, 1,2-dibromoheptane, and 1,6-dibromooctane.

4. The method for preparing the thienoindole self-assembly small molecule compound according to claim 2, characterized in that: In step a, the heating reflux temperature is 70 to 100 o C.

5. The method for preparing the thienoindole self-assembly small molecule compound according to claim 2, characterized in that: In step b, the nucleophilic reagent is triethyl phosphite; and the inert gas is either nitrogen or argon.

6. The method for preparing the thienoindole self-assembly small molecule compound according to claim 2, characterized in that: In step b, the heating temperature is 150-160 o C, time is 24h.

7. The method for preparing the thienoindole self-assembly small molecule compound according to claim 2, characterized in that: In step c, the organic solvent is any one of N,N-dimethylformamide and 1,4-dioxane; the halogenated silylating agent is any one of trimethylbromosilane, trimethylchlorosilane, tetramethyldisilane and tetramethyltetrachlorosilane.

8. The method for preparing the thienoindole self-assembly small molecule compound according to claim 2, characterized in that: In step d, the organic solvent is any one of methanol, ethanol, propanol, and propylene glycol; the water is deionized water; and the organic solvent is tetrahydrofuran and petroleum ether.

9. Use of the thienoindole self-assembled small molecule compound according to claim 1 in an inverse perovskite solar cell.

10. The use according to claim 9, characterized in that: The device structure of the inverted perovskite solar cell is: ITO / hole transport material / MAPbI3 / PCBM / Ag, and the hole transport material adopts the thienoindole self-assembled small molecule compound.

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