CN110606816A - Water-soluble hole transport material for polymer solar cell and preparation method thereof - Google Patents

Abstract

The invention relates to a water-soluble hole transport material for polymer solar cells and a preparation method thereof. The preparation method specifically obtains an intermediate product A through the addition reaction of fluorene and 1,4 butane sultone, and the intermediate product A is brominated Then with 3-(trifluoromethoxy) phenylboronic acid coupling reaction, the final product 2,7-two (3-(trifluoromethoxy))-[9,9-(4,4-two ‑Potassium Butanesulfonate)‑Fluorene. The water-soluble hole transport material prepared by the invention is used in polymer solar cells, can be processed in aqueous solution, is environmentally friendly, and has high photoelectric conversion efficiency.

Description

Water-soluble hole transport material for polymer solar cell and preparation method thereof

technical field

The invention relates to a water-soluble hole transport material for a polymer solar cell and a preparation method thereof, specifically belonging to the technical field of photoelectric materials.

background content

The energy problem is the biggest problem faced by human beings. Solar energy is the most common and most green energy source. Utilizing solar energy is one of the ways to solve human energy problems. Currently researched and developed solar cells include: silicon solar cells and organic solar cells. Although the energy conversion efficiency of silicon solar cells is high, the cost of raw materials is high and the production process will cause relatively large pollution.

Polymer solar cell is a new type of solar cell, which has the advantages of low cost, soft and light, easy to carry and high photoelectric conversion efficiency. The hole transport layer is an essential part of polymer solar cells, which has an important impact on the photoelectric conversion efficiency and stability of the cell.

Currently, the most commonly used polymeric hole transport material for polymer solar cells is poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDEOT:PSS). PEDOT:PSS can be processed in aqueous solution and is suitable for large-scale and large-area production. Stir slowly for 5 minutes, then add hydrochloric acid dropwise to control the pH range of the system to 2~3, then slowly drop into the mixed solution of ammonium persulfate and ferric sulfate, stir quickly for 24 hours, and then use anion exchange resin and cation exchange resin respectively The resin was exchanged for inorganic salt ions for 4 hours to obtain a dark blue solution of PEDOT:PSS. Among them, the molar ratio of PSS to EDOT is 2:1, the molar ratio of ammonium persulfate to EDOT is 1.5:1, and the molar ratio of ferric sulfate to EDOT is 0.002:1. However, PEDEOT:PSS is strongly acidic and will corrode the anode, which is not conducive to the stability of the battery.

In recent years, the hole transport materials of conjugated polymers are relatively rapid, such as poly(4,4-bisbutylsulfonate potassium-alt-benzothiadiazole) (CPE-K), poly[2,6-(4, Sodium 4-di-butylsulfonate-4hydro-cyclopentadieno[2,1-b;3,4-b']dithiophene)-alt-1,4-benzene] (CPEPh-Na). CPE-K and CPEPh-Na are neutral and will not cause corrosion to electrodes; however, their electrical conductivity is low (1.5×10 ^-3 S/cm), and they must be processed very thin to obtain better results, so they are limited Its used on a large scale.

The hole transport material of the present invention has excellent water solubility, good film-forming property, and simple manufacturing process; the material is neutral and does not corrode electrodes, which is conducive to improving the stability of solar cells; the material has relatively high electrical conductivity ( 5.3×10 ^-3 S/cm), high efficiency can be maintained even when the thickness is large, and it is suitable for mass production.

Contents of the invention

Aiming at the problems existing in PEDOT:PSS, the present invention aims to provide a water-soluble hole transport material. Compared with the acidic PEDOT:PSS, the water-soluble hole transport material provided by the invention is neutral, which is beneficial to improve the stability of the battery.

The chemical structural formula of a water-soluble hole transport material for a polymer solar cell of the present invention is:

Described preparation method is:

Step 1: Add 1.0 molar parts of fluorene and 150.0 ml of tetrahydrofuran to a glass reactor at -78 ° C, then add 2.0 molar parts of n-butyllithium, stir magnetically for 45 minutes, and then add 2.0 molar parts of 1,4 butyl to the reactor sultone, then the temperature of the reactor was raised to room temperature, and the reaction was performed under magnetic stirring at room temperature for 8.0 hours, then all the reactants in the reactor were poured into 200.0 ml of distilled water, stirred mechanically at room temperature for 30 minutes, and then extracted the aqueous solution with 150.0 ml of ether, Separate the liquid, take the ether phase, dry the ether phase with 25.0 g of anhydrous sodium sulfate, then suction filter, remove the anhydrous sodium sulfate, take the filtrate, then distill the filtrate under reduced pressure at 40°C, remove the ether, and obtain the intermediate product A;

Step 2: first wrap the glass reactor completely with 2.0 mm thick tin foil, then add 1.0 mole parts of intermediate product A and 100.0 ml of chloroform to the glass reactor at 0 °C, and then add 2.0 moles of liquid bromine and 24.0 grams of ferric chloride, the temperature of the reactor was raised to room temperature, and the reaction was carried out by magnetic stirring at room temperature for 24.0 hours, then all the solutions in the reactor were poured into 100.0 milliliters of distilled water, mechanically stirred at room temperature for 30 minutes, and then extracted with 200.0 milliliters of dichloromethane Aqueous solution, liquid separation, take the dichloromethane phase, dry the dichloromethane phase with 40.0 grams of anhydrous sodium sulfate, then suction filter to remove anhydrous sodium sulfate, and distill the filtrate under reduced pressure at 50°C to remove dichloromethane and chloroform, Obtain intermediate product B;

Step 3: Add 1.0 mole parts of intermediate product B and 3-(trifluoromethoxy)phenylboronic acid to a glass reactor, then add 50.0 ml of N,N-dimethylformamide, stir magnetically at room temperature for 30 minutes, and then The way of bubbling is 1.0 liter/min flow rate of nitrogen gas for 1.0 hour, then add 0.04~0.05 mole of tetrakistriphenylphosphine palladium and 30.0 ml of 1.0 mole/liter potassium carbonate aqueous solution, and the reaction kettle is turned on at a speed of 10 ℃/min. Raise the temperature to 90~100°C, keep the temperature at 90~100°C for 24.0~36.0 hours with magnetic stirring, stop the reaction, cool down to room temperature, pour all the reactants in the reactor into 100.0 ml of acetone, stir magnetically at room temperature for 30 minutes, and filter with suction , the final product 2,7-bis(3-(trifluoromethoxy))-[9,9-(4,4-di-butylsulfonate potassium)-fluorene was obtained as a pale yellow solid.

Beneficial effects of the present invention:

The water-soluble hole-transporting material of the invention can be processed in an aqueous solution, can be produced in a large scale and in a large area, and the aqueous solution is green and environment-friendly.

The water-soluble hole transport material of the present invention has a neutral aqueous solution, does not corrode electrodes, and is beneficial to improving battery stability.

The water-soluble hole-transporting material of the invention is a small molecule, and the preparation process is simple.

Description of drawings

Fig. 1 is the chemical structural formula of the water-soluble small molecule hole transport material of the present invention.

Detailed ways

The present invention is illustrated by the following examples, but is not limited to the following examples. Under the condition of not changing the gist before and after, all changes and implementations are included in the technical scope of the present invention.

Example 1

Step 1: Add 1.0 molar parts of fluorene and 150.0 ml of tetrahydrofuran to a glass reactor at -78 ° C, then add 2.0 molar parts of n-butyllithium, stir magnetically for 45 minutes, and then add 2.0 molar parts of 1,4 butyl to the reactor sultone, then the temperature of the reactor was raised to room temperature, and the reaction was performed under magnetic stirring at room temperature for 8.0 hours, then all the reactants in the reactor were poured into 200.0 ml of distilled water, stirred mechanically at room temperature for 30 minutes, and then extracted the aqueous solution with 150.0 ml of ether, Separate the liquid, take the ether phase, dry the ether phase with 25.0 g of anhydrous sodium sulfate, then suction filter, remove the anhydrous sodium sulfate, take the filtrate, then distill the filtrate under reduced pressure at 40°C, remove the ether, and obtain the intermediate product A;

Step 2: first wrap the glass reactor completely with 2.0 mm thick tin foil, then add 1.0 mole parts of intermediate product A and 100.0 ml of chloroform to the glass reactor at 0 °C, and then add 2.0 moles of liquid bromine and 24.0 grams of ferric chloride, the temperature of the reactor was raised to room temperature, and the reaction was carried out by magnetic stirring at room temperature for 24.0 hours, then all the solutions in the reactor were poured into 100.0 milliliters of distilled water, mechanically stirred at room temperature for 30 minutes, and then extracted with 200.0 milliliters of dichloromethane Aqueous solution, liquid separation, take the dichloromethane phase, dry the dichloromethane phase with 40.0 grams of anhydrous sodium sulfate, then suction filter to remove anhydrous sodium sulfate, and distill the filtrate under reduced pressure at 50°C to remove dichloromethane and chloroform, Obtain intermediate product B;

Step 3: Add 1.0 mole parts of intermediate product B and 3-(trifluoromethoxy)phenylboronic acid to a glass reactor, then add 50.0 ml of N,N-dimethylformamide, stir magnetically at room temperature for 30 minutes, and then The bubbling mode 1.0 liters/min flow rate feeds nitrogen for 1.0 hour, then adds 0.04 mole tetrakistriphenylphosphine palladium and 30.0 milliliters of 1.0 mol/liter potassium carbonate aqueous solution, with the speed of 10 ℃/min, the reaction kettle is heated up to 90°C, constant temperature and magnetic stirring at 90°C for 24.0 hours, stop the reaction, cool down to room temperature, pour all the reactants in the reactor into 100.0 ml of acetone, stir magnetically at room temperature for 30 minutes, and filter with suction to obtain the final product 2 as a light yellow solid , 7-bis(3-(trifluoromethoxy))-[9,9-(4,4-di-butylsulfonate potassium)-fluorene.

Example 2

Step 1: Add 1.0 molar parts of fluorene and 150.0 ml of tetrahydrofuran to a glass reactor at -78 ° C, then add 2.0 molar parts of n-butyllithium, stir magnetically for 45 minutes, and then add 2.0 molar parts of 1,4 butyl to the reactor sultone, then the temperature of the reactor was raised to room temperature, and the reaction was performed under magnetic stirring at room temperature for 8.0 hours, then all the reactants in the reactor were poured into 200.0 ml of distilled water, stirred mechanically at room temperature for 30 minutes, and then extracted the aqueous solution with 150.0 ml of ether, Separate the liquid, take the ether phase, dry the ether phase with 25.0 g of anhydrous sodium sulfate, then suction filter, remove the anhydrous sodium sulfate, take the filtrate, then distill the filtrate under reduced pressure at 40°C, remove the ether, and obtain the intermediate product A;

Step 2: first wrap the glass reactor completely with 2.0 mm thick tin foil, then add 1.0 mole parts of intermediate product A and 100.0 ml of chloroform to the glass reactor at 0 °C, and then add 2.0 moles of liquid bromine and 24.0 grams of ferric chloride, the temperature of the reactor was raised to room temperature, and the reaction was carried out by magnetic stirring at room temperature for 24.0 hours, then all the solutions in the reactor were poured into 100.0 milliliters of distilled water, mechanically stirred at room temperature for 30 minutes, and then extracted with 200.0 milliliters of dichloromethane Aqueous solution, liquid separation, take the dichloromethane phase, dry the dichloromethane phase with 40.0 grams of anhydrous sodium sulfate, then suction filter to remove anhydrous sodium sulfate, and distill the filtrate under reduced pressure at 50°C to remove dichloromethane and chloroform, Obtain intermediate product B;

Step 3: Add 1.0 mole parts of intermediate product B and 3-(trifluoromethoxy)phenylboronic acid to a glass reactor, then add 50.0 ml of N,N-dimethylformamide, stir magnetically at room temperature for 30 minutes, and then The bubbling mode 1.0 liters/min flow rate feeds nitrogen for 1.0 hour, then adds 0.05 mole tetrakistriphenylphosphine palladium and 30.0 milliliters of 1.0 mol/liter potassium carbonate aqueous solution, with the speed of 10 ℃/min, the reaction kettle is heated up to 100°C, constant temperature and magnetic stirring reaction at 100°C for 36.0 hours, stop the reaction, cool down to room temperature, pour all the reactants in the reactor into 100.0 ml acetone, stir magnetically at room temperature for 30 minutes, and filter with suction to obtain the final product 2 as a light yellow solid , 7-bis(3-(trifluoromethoxy))-[9,9-(4,4-di-butylsulfonate potassium)-fluorene.

Take 0.2 gram of 2,7-bis(3-(trifluoromethoxy))-[9,9-(4,4-di-butylsulfonate potassium)-fluorene respectively from Example 1 or Example 2, Dissolved in 10.0 ml of water, stirred mechanically at room temperature for 30 minutes, then passed the solution through a 2.2-micron filter head to obtain 2,7-bis(3-(trifluoromethoxy))-[9,9-(4,4- Potassium di-butylsulfonate)-fluorene solution.

The pH of the solution was tested using a SevenGo™ pH-SG2 pH meter.

The hole mobility (μ _h ) of the two examples was tested by the space charge limited current method. The device structure is: indium tin oxide glass (ITO)/2,7-bis(3-(trifluoromethoxy))-[9,9-(4,4-bis) prepared in Example 1 or Example 2 - potassium butylsulfonate) - fluorene/gold (Au). The spin coating condition of 2,7-bis(3-(trifluoromethoxy))-[9,9-(4,4-di-butylsulfonate potassium)-fluorene solution was 3000 rpm for 30 seconds. Au is processed by vacuum evaporation, and the evaporation thickness is 70~80 nanometers.

Test the photoelectric conversion efficiency of 2,7-bis(3-(trifluoromethoxy))-[9,9-(4,4-di-butylsulfonate potassium)-fluorene by forward organic solar cell device . The device structure is: ITO/2,7-bis(3-(trifluoromethoxy))-[9,9-(4,4-di-butylsulfonate potassium) prepared in Example 1 or Example 2 -Fluorene/poly[2-ethylhexyl-6-(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b′ ]dithiophen-2-yl)-3-fluorothieno[3,4-b]thiophene-2-carboxy](PBDTTT-EFT), and [6,6]-phenyl C71 butyric acid methyl ester (PC ₇₁ BM) blended active layer/PFN/aluminum (Al). 2,7-Bis(3-(trifluoromethoxy))-[9,9-(4,4-di-butylsulfonate potassium)-fluorene was spin-coated at 3000 rpm for 35 seconds. The mass ratio of PBDTTT-EFT to PC ₇₁ BM is 1:1. The thickness of PFN is 5~10 nanometers. Al evaporation thickness is 80~100 nanometers. For comparison, an organic solar cell with the same structure was also fabricated using PEDOT:PSS (4083) hole transport layer. Further, the photoelectric conversion efficiency of the prepared organic solar cell was tested by Keithley2400 system. The photoelectric conversion efficiency is an average value of 10 cells.

The photoelectric conversion efficiency and other data of the battery are as follows:

μ _h is the hole mobility, and V _oc is the open circuit voltage. J _sc is the short-circuit current, FF is the fill factor, PCE is the energy conversion efficiency, and S is the battery stability.

Claims (2)

1. A water-soluble hole transport material for a polymer solar cell, characterized in that: the chemical structural formula of the water-soluble hole transport material is as follows:

。

2. a water-soluble hole transport material for a polymer solar cell and a preparation method thereof are characterized in that: the preparation method comprises the following steps:

step 1: adding 1.0 mol part of fluorene and 150.0 ml of tetrahydrofuran into a glass reaction kettle at the temperature of-78 ℃, adding 2.0 mol part of n-butyllithium, magnetically stirring for 45 minutes, adding 2.0 mol part of 1, 4-butanesultone, raising the temperature of the glass reaction kettle to room temperature, magnetically stirring for reaction for 8.0 hours at the room temperature, pouring a reaction product into 200.0 ml of distilled water, mechanically stirring for 30 minutes at the room temperature, extracting an aqueous solution with 150.0 ml of diethyl ether, taking an diethyl ether phase after liquid separation, drying the diethyl ether phase with 25.0 g of anhydrous sodium sulfate, carrying out suction filtration, removing the anhydrous sodium sulfate, distilling the filtrate at the temperature of 40 ℃ under reduced pressure, and removing the diethyl ether to obtain an intermediate product A;

step 2: completely wrapping a glass reaction kettle by using 2.0 mm thick tinfoil, adding 1.0 mol part of intermediate product A and 100.0 ml of trichloromethane into the glass reaction kettle at 0 ℃, adding 2.0 mol part of liquid bromine and 24.0 g of ferric trichloride, raising the temperature of the glass reaction kettle to room temperature, carrying out magnetic stirring reaction at the room temperature for 24.0 hours, pouring 100.0 ml of distilled water into the reaction product, mechanically stirring for 30 minutes at the room temperature, extracting with 200.0 ml of dichloromethane, separating liquid, taking a dichloromethane phase, drying the dichloromethane phase by using 40.0 g of anhydrous sodium sulfate, carrying out suction filtration to remove the anhydrous sodium sulfate, and distilling the obtained filtrate at 50 ℃ under reduced pressure to remove dichloromethane and trichloromethane to obtain an intermediate product B;

and 3, adding 1.0 mol part of the intermediate product B and 3- (trifluoromethoxy) phenylboronic acid into a glass reaction kettle, adding 50.0 ml of N, N-dimethylformamide, magnetically stirring for 30 minutes at room temperature, introducing nitrogen for 1.0 hour in a bubbling manner at the flow rate of 1.0 liter/minute, adding 0.04 ~ 0.05.05 mol part of tetratriphenylphosphine palladium and 30.0 ml of 1.0 mol/minute aqueous solution of potassium carbonate, heating the glass reaction kettle to 90 ~ 100 ℃ at the speed of 10 ℃/minute, magnetically stirring for 24.0 ~ 36.0.0 hours at the temperature of 90 ~ 100 ℃ at 100 ℃, stopping the reaction, cooling to room temperature, pouring the reaction product in the glass reaction kettle into 100.0 ml of acetone, magnetically stirring for 30 minutes at room temperature, and performing suction filtration to obtain a light yellow solid product 2, 7-bis (3- (trifluoromethoxy)) [9, 9- (4, 4-di-butylsulfonic acid potassium) -fluorene.