KR101264082B1 - Photosensitizer containing benzothiazole for photovoltaic cell, and photovoltaic cell including the same - Google Patents

Abstract

The present invention relates to a novel triphenylamine dye for dye-sensitized solar cells containing benzothiazol, wherein the dye according to the present invention has an absorption range and a high light absorption between 400 and 550 nm, It is applied as a sensitizer for solar cells, which can greatly improve the photoelectric conversion efficiency of solar cells.

Description

Dye-sensitized solar cell dye containing benzothiazol and dye-sensitized solar cell using same {PHOTOSENSITIZER CONTAINING BENZOTHIAZOLE FOR PHOTOVOLTAIC CELL, AND PHOTOVOLTAIC CELL INCLUDING THE SAME}

The present invention relates to a dye used in a dye-sensitized solar cell and a dye-sensitized solar cell using the same, and more particularly, to a novel triphenylamine dye containing benzothiazol having a high molar extinction coefficient between 400 nm and 550 nm. The present invention relates to a dye capable of improving the photoelectric conversion efficiency by manufacturing and applying the same to a light absorbing layer for solar cells.

In recent years, various studies have been conducted to replace existing fossil fuels in order to reduce the emission of carbon dioxide which is the main cause of global warming and to solve the energy problem. Extensive research to harness natural energy such as wind, nuclear power, and solar power has been conducted to replace petroleum resources that will be exhausted in the near future. Among these, solar cells using solar energy are the most environmentally friendly, Unlike other energy sources, resources can be infinite if we only develop appropriate methods of use. In addition, it is attracting attention as an alternative renewable energy because self-generation is possible as an energy source of information and communication devices. Since solar cells using selenium (Se) were developed in 1983, silicon solar cells have been in the spotlight in recent years, but they are limited in practical use because they are quite expensive in terms of manufacturing cost, and the efficiency of the batteries is still quite insufficient. To overcome this problem, the development of low-cost dye-sensitized solar cells has been progressed by various groups.

Dye-sensitized solar cells absorb the visible energy of light and produce electron-hole pairs.The photoelectrochemical system consists mainly of photosensitive dye molecules and transition metal oxides that transfer the generated electrons. It is a solar cell. A dye-sensitized solar cell using nanoparticle titanium oxide, developed in 1991 by Michael Gratzel of the Swiss National Institute of Advanced Technology (EPFL), is a representative example of conventional dye-sensitized solar cells.

The dye-sensitized solar cell developed by them has the advantage that it can be applied to building exterior wall glass windows or glass greenhouses due to the transparent electrode, and it is cheaper to manufacture than the conventional silicon solar cell, but the photoelectric conversion efficiency is low, so the practical application is limited. have.

Photoelectric conversion efficiency is proportional to the amount of electrons generated by the absorption of sunlight. In order to increase the efficiency of solar cells, it is possible to increase the absorption of sunlight or increase the amount of dye adsorbed in order to generate more electrons or to prevent the generated exciton from being dissipated by electron-hole recombination. It may be. In order to increase the absorption of sunlight, it is possible to increase the reflectance of the platinum electrode or to manufacture the particles of the oxide semiconductor to nanometer size to increase the adsorption amount of the dye per unit area. Methods have been developed. However, such a conventional method has a limitation in improving the photoelectric conversion efficiency of the solar cell, and thus, there is an urgent need for the development of a new technology for improving the efficiency, in particular, the development of a new dye having high photoelectric conversion efficiency.

An object of the present invention is to provide a dye for a dye-sensitized solar cell exhibiting a high light absorption, to provide a dye-sensitized solar cell with improved photoelectric conversion efficiency comprising the dye.

In order to solve the above problems, according to a preferred embodiment of the present invention, there is provided a dye for a solar cell dye comprising a compound having a structure of formula (1).

[Formula 1]

Wherein D ₁ and D ₂ are substituted or unsubstituted aromatic hydrocarbon groups, substituted or unsubstituted aromatic heterocyclic groups, and combinations thereof, and C and B are substituted or unsubstituted aromatic hydrocarbon groups , A substituted or unsubstituted hetero ring group, a vinyl group, a substituted or unsubstituted polyvinyl group, and A is an acidic functional group.

According to another suitable embodiment of the present invention, the D ₁ and D ₂ are each a dye for a solar cell dye, characterized in that it comprises a substituent selected from the group consisting of alkyl, alkoxy, aryl group, arylene group, or alkylene group To provide.

According to another suitable embodiment of the present invention, each of B and C is independently a vinyl group, a polyvinyl group, benzene, naphthalene, anthracene, fluorene, biphenyl, furan, pyrrole, thiophene, carbazole and their It provides a dye for a dye-sensitized solar cell, characterized in that selected from the group consisting of a combination.

According to another suitable embodiment of the present invention, the B and C are each independently a dye characterized in that it comprises a substituent selected from the group consisting of alkyl, alkoxy, aryl group, arylene group, alkylene group and combinations thereof It provides a dye for sensitized solar cells.

According to another suitable embodiment of the present invention, A is selected from the group consisting of a carboxyl group, phosphorous acid group, sulfonic acid group, phosphinic acid group, hydroxy group, oxycarboxylic acid, acidamide and combinations thereof A battery dye is provided.

According to another suitable embodiment of the present invention, the dye provides a dye for a solar cell dye, characterized in that one selected from the group consisting of a compound having a structure of the formula 2 to 4 and combinations thereof.

[Formula 2]

(3)

[Formula 4]

In addition, according to another suitable embodiment of the present invention, there is provided a dye-sensitized solar cell element using the dye.

Dye-sensitized solar cell dye of the present invention has a high molar extinction coefficient between 400 ~ 550nm region, can be applied to the light absorption layer for solar cells to increase the photoelectric conversion efficiency.

1 is a schematic view showing a dye-sensitized solar cell according to an embodiment of the present invention.
2 is an ultraviolet-visible light absorption wavelength according to the dye of Example 3. FIG.
3 is an IPCE curve of the dye-sensitized solar cell prepared in Example 6. FIG.

Hereinafter, the present invention will be described in more detail.

The first step in driving a solar cell in a dye-sensitized solar cell is the process of generating a photo charge from solar energy. Typically, a dye material is used for generating a photo charge, and the dye material is excited by absorbing light transmitted through the conductive transparent substrate.

Metal dye compounds are widely used as the dye material, and mono, bis, or tris (substituted 2,2′-bipyridine) complex salts of ruthenium are generally used among the metal complex compounds. However, they have a problem in that the efficiency of the electrons excited by light in the ground state of the metal complex falls back to the ground state is relatively high, which is low. In order to solve this problem, there have been many reports of introducing various electron transfer materials to metal complexes through covalent bonds. However, the introduction of electron transfer materials through covalent bonds has a problem that the process is very complicated and difficult to introduce various electron transfer materials.

In order to solve the above problems, the present invention provides a dye-sensitized embodiment by preparing and using a dye of a compound including a benzothiazol structure in a bridge group of a conventional triphenylamine dye structure and introducing a variety of electron donor groups and bridge groups. The photoelectric conversion efficiency of the battery was improved.

More specifically, the dye-sensitized solar cell dye of the present invention comprises a compound of formula (1).

[Formula 1]

In Formula 1, D ₁ and D ₂ is a substituent consisting of a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group and a combination thereof, C and B is a substituted or unsubstituted aromatic hydrocarbon group , A substituted or unsubstituted hetero ring group, a vinyl group, a substituted or unsubstituted polyvinyl group, and A is an acidic functional group.

Specific examples of the aromatic hydrocarbon group may include benzene, naphthalene, anthracene, fluorene, phenyl, biphenyl group, xylene, phenanthryl, perylene, and combinations thereof.

In addition, the aromatic hetero ring group is preferably selected from the group consisting of pyran, pyrrole, thiophene, carbazole, phenothiazine, phenooxazine, and combinations thereof.

In addition, D ₁ and D ₂ may include a substituent, and the substituent is preferably selected from the group consisting of alkyl, alkoxy, aryl group, arylene group, alkylene group, amino group and combinations thereof.

In the substituent, the alkyl group is preferably selected from the group consisting of substituted or unsubstituted alkyl groups having 1 to 10 carbon atoms. The alkoxy group is preferably selected from the group consisting of an oxygen-containing substituted or unsubstituted alkoxy group having an alkyl group having 1 to 10 carbon atoms. The aryl group may be used alone or in combination, and is preferably an aromatic compound having 6 to 20 carbon atoms containing at least one ring, such as phenyl, naphthyl, tetrahydronaphthyl, indan or biphenyl. The alkylene group has the form of a radical to which both ends of the alkyl group can be bonded, wherein the alkyl group is as defined above.

In Formula 1, B and C are each independently selected from a vinyl group, polyvinyl group, benzene, naphthalene, anthracene, fluorene, biphenyl, furan, pyrrole, thiophene, carbazole and combinations thereof It is preferable.

In addition, the B and C may include a substituent consisting of alkyl, alkoxy, aryl group, alkenyl group, arylene group, alkylene group, amino group and combinations thereof. The substituents are the same as described above for D ₁ and D ₂ .

In Formula 1, A is preferably an acid functional group, and is preferably selected from the group consisting of carboxyl groups, phosphorous acid groups, sulfonic acid groups, phosphinic acid groups, hydroxy groups, oxycarboxylic acids, acid amides, and combinations thereof. Preferably carboxyl.

In the present invention, the dye-sensitized solar cell dye is more preferably at least one selected from the group consisting of a compound having a structure of the following formulas (2) to (4) and combinations thereof.

[Formula 2]

(3)

[Formula 4]

1 is a cross-sectional view schematically showing the structure of a dye-sensitized solar cell according to an embodiment of the present invention.

Referring to FIG. 1, the dye-sensitized solar cell 10 has a sandwich structure in which two plate electrodes (working electrode 11 and counter electrode 14) are surface-bonded to each other. The light absorbing layer 12 is formed on one surface of the transparent electrode facing the relative electrode 14, and the light absorbing layer 12 is adsorbed by the semiconductor fine particles and the semiconductor fine particles to form electrons with visible light absorption. Photosensitive dyes are excited. In addition, the space between the two electrodes is filled with the redox electrolyte 13.

Therefore, when sunlight enters into the dye-sensitized solar cell 10, the photons are first absorbed by the dye molecules in the light absorbing layer 12. Accordingly, the dye molecules are electron-transferred from the ground state to the excited state to form electron-hole pairs. The electrons in the state are injected into the conduction band of the metal oxide particle interface, and the injected electrons are transferred to the working electrode 11 through the interface and move to the state electrode 14, which is the counter electrode, through an external circuit. . On the other hand, the dye oxidized as a result of the electron transfer is reduced by the ions of the redox couple in the electrolyte 13, and the oxidized ions reach the interface of the second electrode 14 to achieve charge neutrality. The fuel-sensitized solar cell 10 operates by reducing with electrons.

The working electrode 11 includes a transparent substrate and a conductive layer formed on the transparent substrate.

The transparent substrate is not particularly limited as long as it is a material having transparency to allow incidence of external light. Therefore, the transparent substrate may be made of glass or plastic. Examples of the plastic include polyethylene terephtalate (PET), polyethylene napthalate (PEN), polycarbonate (PC), polypropylene (PP), polyimide (PI), and triacetyl. It may be used as cellulose (triacetyl cellulose, TAC) or a copolymer thereof.

The transparent substrate may be doped with a material selected from the group consisting of Ti, In, Ga, and Al.

A conductive layer is positioned on the transparent substrate. The conductive layer is fluorine tin oxide (FTO), indium tin oxide (ITO), ZnO- (Ga ₂ O ₃ or Al ₂ O ₃ ), tin oxide, antimony tin oxide (antimony tin oxide) oxide, ATO), zinc oxide (zinc oxide) and a conductive metal compound selected from the group consisting of a mixture thereof may be used, more preferably florin tin oxide may be used.

The semiconductor fine particles may be a compound having a compound semiconductor or a perovskite structure in addition to a semiconductor represented by silicon.

The semiconductor is preferably an n-type semiconductor in which conduction band electrons become carriers under photo excitation to provide an anode current, and the compound semiconductor is Ti, Zr, Sr, Zn, In, Yr, La, V, Mo, W Oxides of metals selected from the group consisting of Sn, Nb, Mg, Al, Y, Sc, Sm, Ga, In and TiSr can be used. Preferably, TiO ₂ , SnO ₂ , ZnO, WO ₃ , Nb ₂ O ₅ , TiSrO ₃ or a mixture thereof may be used, and more preferably TiO ₂ may be used. The kind of the semiconductor is not limited to these.

In addition, the semiconductor fine particles preferably have a large surface area in order for the dye adsorbed on the surface to absorb more light. Therefore, the semiconductor fine particles preferably have an average particle diameter of 50 nm or less, and more preferably, may have an average particle diameter of 15 to 20 nm. When the particle diameter exceeds 50 nm, the surface area becomes small, which may lower the catalyst efficiency.

A dye for absorbing external light and generating excitation electrons is adsorbed on the surface of the semiconductor fine particles. The dye is the same as described above.

The counter electrode 14 is positioned to face the working electrode 11 on which the light absorption layer 12 is formed. The counter electrode 14 includes a transparent substrate and a transparent electrode and a catalyst electrode (not shown) formed on the transparent substrate so as to face the working electrode 11.

The transparent substrate may be made of glass or plastic as in the working electrode. Examples of the plastic include polyethylene terephtalate (PET), polyethylene napthalate (PEN), polycarbonate (PC), polypropylene (PP), polyimide (PI), and triacetyl. Cellulose (triacetyl cellulose, TAC) or copolymers thereof may be used.

A transparent electrode is formed on the transparent substrate, and the transparent electrode is made of fluorine tin oxide (FTO), indium tin oxide (ITO), ZnO- (Ga ₂ O ₃ or Al ₂ O ₃ ), A conductive metal compound selected from the group consisting of tin oxide, antimony tin oxide (ATO), zinc oxide, and mixtures thereof may be used, and more preferably florine tin oxide may be used. .

In addition, a catalyst electrode is formed on the transparent electrode. The catalyst electrode serves to activate a redox couple, platinum (Pt), gold (Au), ruthenium (Ru), palladium (Pd), rhodium (Rh), iridium (Ir), Conductive materials such as osmium (Os), WO ₃ , TiO ² and conductive polymers.

In addition, the catalytic electrode side facing the working electrode for the purpose of improving the catalytic effect of redox is preferable to have a microstructure to increase the surface area. For example, Pt or Au may be in a black state, and carbon may be in a porous state.

The counter electrode 14 includes a hole (not shown) penetrating the counter electrode to inject the electrolyte.

The electrolyte layer is composed of an electrolyte solution, and the electrolyte solution serves to transfer dye by receiving electrons from a counter electrode by oxidation and reduction, wherein the voltage of the open circuit is determined by the energy level of the dye and oxidation and reduction levels of the electrolyte. It is determined by the difference.

As the electrolyte solution, for example, a solution in which iodine is dissolved in acetonitrile can be used, but is not necessarily limited thereto.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited or limited by the following Examples.

Example  Preparation of Dye Having Structure of 1-Formula 2

The dye compound 1 having the structure of Chemical Formula 2 was prepared by following the steps shown in Scheme 1.

[Reaction Scheme 1]

[Formula 2]

(1) Synthesis of 2-Bromo-6-methylbenzothiazole (Intermediate Compound (1))

In an ice bath, 100 ml of acetonitrile was added to a 250 ml round bottom flask and 3.285 g (20 mmol) of 2-amino-6-methylbenzothiazole, CuBr ₂ 6.71 Stir while dissolving g (30 mmol). To the mixture is slowly added 3.1 g (30 mmol) of tert-butylnitrile (90%) over 5 minutes. The mixture is stirred at room temperature for 1 hour and then slowly warmed up to 65 ° C for 1 hour. At the end of the reaction, the reaction mixture was cooled to room temperature and the mixture was dissolved in ethyl acetate. Then, 6M aqueous HCl solution and concentrated NaHCO _{3 were added.} Extract with aqueous solution, saturated salt and water. After extraction, the organic solution is passed through MgSO ₄ to remove moisture, and the filtrate is removed using a rotary vacuum distillation apparatus. After drying for one day in an oven at 50 ℃, it was purified by silica gel chromatography (developing solvent, chloroform: hexane = 2: 1) to obtain 4.19g. (Yield 92%)

(2) 2-Bromo-6- (bromomethyl) benzothiazole) Synthesis of 2-Bromo-6- (bromomethyl) benzothiazole, intermediate compound (2))

Under nitrogen atmosphere, 3.18 g (13.94 mmol) of intermediate compound (1), 2.73 g (15.34 mmol) of N-Bromosuccinimide (NBS) and Benzoyl peroxide (BPO) in a 100 ml round bottom flask ) 0.118 g (0.488 mmol) is dissolved in 60 ml of CCl ₄ and refluxed for 4 hours. The reaction was cooled to room temperature, filtered under reduced pressure, and the filtrate was removed using a rotary vacuum distillation apparatus and dried in a 50 ° C. oven for one day. When the drying was completed, the residue was purified by silica gel chromatography (eluent, ethyl acetate: hexane = 1: 6) to obtain 2.69 g. (Yield 63%)

(3) Synthesis of 2-bromo-6- (diethylphosphomethyl) benzothiazole (2-Bromo-6- (diethylphosphonomethyl) benzothiazole, intermediate compound (3))

Under argon atmosphere, 4.5 g (14.66 mmol) of the intermediate compound (2) and 3.66 g (22 mmol) of triethylphosphite were refluxed at 160 ° C. for 7 hours in a 100 ml round bottom flask. Excess triethylphosphite is removed under reduced pressure and used in the next step without purification.

(4) (E) -4- (2- (2-bromobenzothiazol-6-yl) vinyl) -N, N-diphenylbenzeneamine ((E) -4- (2- (2-bromobenzothiazol Synthesis of -6-yl) vinyl) -N, N-diphenylbenzenamine, Intermediate Compound (4))

In an argon atmosphere, 2.93 g (8.05 mmol) of intermediate compound (3) and 1.43 g (12.08 mmol) of potassium tert-butoxide were added to a 250 ml round bottom flask with 50 ml of anhydrous tetrahydrofuran (THF). To dissolve). 2.2 g (8.05 mmol) of 4- (N, N-diphenylamino) -benzaldehyde was dissolved in 20 ml of anhydrous tetrahydrofuran and then in the gastric solution for 5 minutes. Add slowly The mixture is stirred at room temperature for 8 hours and then poured 50 ml of cold distilled water. 10 ml of 6M HCl aqueous solution was added to the solution, and the precipitate precipitate was filtered under reduced pressure and dried in a 50 ° C. oven for one day. The dried material was purified by silica gel chromatography (eluent, methylene chloride) to give a pale yellow powder.

(5) (E) -4- (6- (4- (diphenylamino) styryl) benzothiazol-2-yl) benzaldehyde ((E) -4- (6- (4- (diphenylamino) styryl Synthesis of) benzothiazol-2-yl) benzaldehyde, Intermediate Compound (5))

Under argon atmosphere, 0.629 g (1.3 mmol) of the intermediate compound (4) are dissolved in a mixed solvent of 50 ml of anhydrous toluene and 10 ml of anhydrous ethanol in a 100 ml round bottom flask. To the mixture was added 0.234 g (1.56 mmol) of 4-formylphenylboronic acid, 0.075 g (0.065 mmol) of Pd (PPh ₃ ) ₄ and 9 ml of 2M K ₂ CO ₃ aqueous solution, respectively, at 115 ° C. Reflux for 24 hours. After the reaction is cooled to room temperature and extracted with methylene chloride and water. The organic solution layer passes through MgSO ₄ to remove moisture, and then the organic solvent is removed using a rotary vacuum distillation apparatus. After drying in an oven at 50 ° C. for one day, the product was purified by silica gel chromatography (eluent, methylene chloride) to obtain 0.58 g of a yellow powder. (Yield 86%)

(6) Synthesis of Dye Compound 1 Having the Structure of Formula 2

Under a nitrogen atmosphere, 0.57 g (1.12 mmol) of the intermediate compound (5) is dissolved in 60 ml of anhydrous acetonitrile in a 100 ml round bottom flask. 0.286 g (3.36 mmol) of cyanoacetic acid and 0.382 g (4.48 mmol) of piperidine were added to the gas solution, and the mixture was refluxed at 92 ° C. for 5 hours. After the reaction, the mixture is cooled to room temperature, and the organic solvent is removed by using a rotary vacuum distillation apparatus. After drying in an oven at 50 ° C. for one day, the mixture was purified by silica gel chromatography (eluent, chloroform: methanol = 3: 1). The purified product was dissolved in 50 ml of methylene chloride and 50 ml of 0.1 M HCl aqueous solution was added thereto, followed by stirring for 2 hours. After stirring, the mixture is extracted with methylene chloride and passed through MgSO ₄ . The organic solvent was removed using a rotary distillation apparatus and dried in a 50 ° C. oven for one day to obtain 0.47 g of orange powder. (Yield: 73%)

Example  2: Preparation of Dye Having Structure of Formula 3

Dye compound 2 having a structure of Chemical Formula 3 was prepared by following the steps shown in Scheme 2. Intermediate compound (4) was prepared in the same manner as in Example 1 in the following scheme.

[Reaction Scheme 2]

(3)

(1) Synthesis of (E) -5- (6- (4- (diphenylamino) styryl) benzothiazol-2-yl) thiophene-2-carbaldehyde (Intermediate Compound (6))

Under argon atmosphere, 0.725 g (1.5 mmol) of the intermediate compound (4) are dissolved in a mixed solvent of 50 ml of anhydrous toluene and 10 ml of anhydrous ethanol in a 100 ml round bottom flask. 0.281 g (1.8 mmol) of 5-formyl-2-thiophene boronic acid, 0.087 g (0.075 mmol) of Pd (PPh ₃ ) ₄ and 2M K ₂ CO ₃ 10 ml of aqueous solution is added, and refluxed at 115 ° C. for 24 hours. After the reaction is cooled to room temperature and extracted with methylene chloride and water. The organic solution layer passes through MgSO ₄ to remove moisture, and then the organic solvent is removed using a rotary vacuum distillation apparatus. After drying in an oven at 50 ° C. for one day, the mixture was purified by silica gel chromatography (eluent, methylene chloride) to obtain 0.388 g of a yellow powder. (Yield 50%)

(2) Synthesis of Dye Compound 2 Having the Structure of Formula 3

Under a nitrogen atmosphere, 0.386 g (0.75 mmol) of the intermediate compound (6) is dissolved in 50 ml of anhydrous acetonitrile in a 100 ml round bottom flask. 0.192 g (2.25 mmol) of cyanoacetic acid and 0.256 g (3.0 mmol) of piperidine were added to the gas solution and refluxed at 92 ° C. for 5 hours. After the reaction, the mixture is cooled to room temperature, and the organic solvent is removed by using a rotary vacuum distillation apparatus. After drying in an oven at 50 ° C. for one day, the mixture was purified by silica gel chromatography (eluent, chloroform: methanol = 3: 1). The purified product was dissolved in 50 ml of methylene chloride and 50 ml of 0.1 M HCl aqueous solution was added thereto, followed by stirring for 2 hours. After stirring, the mixture is extracted with methylene chloride and passed through MgSO ₄ . The organic solvent was removed using a rotary distillation apparatus and dried in a 50 ° C. oven for one day to obtain 0.288 g of red powder. (Yield 66%)

Example  3: Preparation of Dye Having Structure of Formula 4

Dye compound 3 having a structure of Chemical Formula 4 was prepared by following the steps shown in Scheme 3 below. Intermediate compound (4) was prepared in the same manner as in Example 1 in the following scheme.

Scheme 3

[Formula 4]

(1) (E) -5- (6- (4- (diphenylamino) styryl) benzo [d] thiazol-2-yl) furan-2-carbaldehyde ((E) -5- (6 Synthesis of-(4- (diphenylamino) styryl) benzo [d] thiazol-2-yl) furan-2-carbaldehyde, Intermediate Compound (7))

Under argon atmosphere, 0.725 g (1.5 mmol) of the intermediate compound (4) are dissolved in a mixed solvent of 50 ml of anhydrous toluene and 10 ml of anhydrous ethanol in a 100 ml round bottom flask. In the above mixture, 0.252 g (1.8 mmol) of 5-formylfuran-2-ylboronic acid, 0.087 g (0.075 mmol) of Pd (PPh ₃ ) ₄ and 10 ml of 2M K ₂ CO ₃ aqueous solution were added. After each addition, reflux at 115 ° C. for 24 hours. After the reaction is cooled to room temperature and extracted with methylene chloride and water. The organic solution layer passes through MgSO ₄ to remove moisture, and then the organic solvent is removed using a rotary vacuum distillation apparatus. After drying for one day in a 50 ℃ oven purified by silica gel chromatography (eluent, methylene chloride) to give 0.434g of yellow powder. (Yield 58%)

(2) Synthesis of Dye Compound 3 Having the Structure of Formula 4

Under a nitrogen atmosphere, 0.42 g (0.84 mmol) of the intermediate compound (7) was dissolved in 50 ml of anhydrous acetonitrile in a 100 ml round bottom flask. 0.214 g (2.52 mmol) of cyanoacetic acid and 0.286 g (3.36 mmol) of piperidine were added to the gas solution, and the mixture was refluxed at 92 ° C. for 5 hours. After the reaction, the mixture is cooled to room temperature, and the organic solvent is removed by using a rotary vacuum distillation apparatus. After drying in an oven at 50 ° C. for one day, the mixture was purified by silica gel chromatography (eluent, chloroform: methanol = 3: 1). The purified product was dissolved in 50 ml of methylene chloride and 50 ml of 0.1 M HCl aqueous solution was added thereto, followed by stirring for 2 hours. After stirring, the mixture is extracted with methylene chloride and passed through MgSO ₄ . The organic solvent was removed using a rotary distillation apparatus and dried in a 50 ° C. oven for one day to obtain 0.337 g of red powder. (Yield 71%)

Example  4: Manufacture of Dye-Sensitized Solar Cell

(1) working electrode fabrication

Cut the FTO substrate (Fluorine-doped tin oxide coated conduction glass, Pilkington, TEC-8) into 1.5cm x 1.5cm size, rub it by hand while washing with acetone to remove impurities such as organic matter on the surface. Deposit twice a minute. Thereafter, the ultrasonic washing is repeated twice for 10 minutes using ethanol. After that, it is rinsed thoroughly with anhydrous ethanol and dried in an oven. In order to improve the contact force with TiO ₂ on the thus prepared FTO substrate, 0.2M titanium butoxide (Titanium (IV) butoxide) solution was coated by spin coating, and the solvent was completely dried in an oven.

After that, TiO ₂ (230 (M2331) -2T) was coated on the FTO substrate by the doctor blade technique, dried in an oven at 100 ° C. for 10 minutes, and then heated to 500 ° C. for 30 minutes to sinter for 9 to 10 minutes. A micrometer thick TiO ₂ transparent layer is obtained. TiO ₂ (CCIC-1T) is coated and sintered thereon in the same manner to obtain a TiO ₂ scattering layer having a thickness of 4 to 5 micrometers.

TiO ₂ thus obtained The film was immersed in a 0.5mM chloroform solution made using the dye synthesized in Example 1 for 40 hours to adsorb the dye onto the TiO ₂ surface. (The solvent used to make the dye solution is a solvent that can dissolve the dye well.) After the adsorption is completed, completely wash the dye that has not been adsorbed with the solvent. Scrape off the adsorbed film leaving only 6.5mm x 6.5mm.

(2) counter electrode fabrication

Using a diamond drill, drill two holes for the electrolyte injection into a 1.5 cm-1.5 cm FTO substrate. Thereafter, it is washed and dried in the same manner as the washing method described above. Then, soak for 20 minutes in 0.7mM hydrogen hexachloroplatinate (H ₂ PtCl ₆ ) 2-propanol solution, take out and heat-treated in an oven at 400 ℃ for 30 minutes.

(3) Sandwich cell production

Between the working electrode and the counter electrode, Sullyn (Surlyn, Dupont 1702) was cut into rectangular bands, and the two electrodes were attached to each other using a hot press. Then, the electrolyte was injected through the two small holes. After that, a sandwich cell is produced by sealing with Surlyn strip and cover glass. The electrolyte solution was 0.2 M LiI, 0.005 M I ₂ , 0.5 M 1-methyl-3-propylimidazolium iodide and 0.5 M 4-tert-butyl Pyridine (4-tert-butylpyridine) was prepared by dissolving acetonite in acetonitrile solvent.

(4) Photocurrent-voltage and Incident Photon to Current Efficiency

When irradiated with a Xe lamp (300W Xe arc lamp) equipped with a solar simulating filter of AM 1.5 to the solar cell manufactured above, the current-voltage curve was generated using a Keithly model 2400 source measuring unit. Got it. In addition, IPCE was measured at a rate of 10 Hz in a 300-800 nm wavelength region using a monochromic beam of a 75 W Xe lamp, and a calibration was performed using a silicon photodiode (NIST-calibrated photodiode G425).

The results of testing the performance of the solar cell thus produced are shown in Table 1 below.

Example  5: Manufacture of Dye-Sensitized Solar Cell

A dye-sensitized solar cell was manufactured in the same manner as in Example 4, except that the compound prepared in Example 2 was used as a dye.

The results of testing the performance of the solar cell thus produced are shown in Table 1 below.

Example  6: Manufacture of Dye-Sensitized Solar Cell

A dye-sensitized solar cell was manufactured in the same manner as in Example 4, except that the compound prepared in Example 3 was used as a dye.

The results of testing the performance of the solar cell thus produced are shown in Table 1 below.

Absorption
λ _abs / nm
(ε / M ^-1 cm ^-1 ) Emission
λ _em / nm Photovoltaic performance data J _sc
/ mAcm ^-2 V _oc
/ mV FF η (%) Example 4 448 (31,000) 512 9.58 681.7 0.727 4.75 Example 5 474 (34,000) 562 9.83 602.6 0.744 4.41 Example 6 470 (33,500) 555 10.28 657.2 0.724 4.89

As a result of testing the performance of the solar cells prepared in Examples 4 to 6, the short circuit current (J _sc ) was 9.58 mAcm ^-2 , 9.83 mAcm ^-2 and 10.28 mAcm ^-2 , respectively, and the open voltage (V _oc ) was 681.7 mV, 602.6 mV and 657.2 mV, and filling factor (FF) had values of 0.727, 0.744 and 0.724, respectively, and the photoelectric conversion efficiencies (η) were 4.75%, 4.41% and 4.89%, respectively. Figure 2 shows the absorption wavelength of the ultraviolet-visible region of the dye compound 3 prepared in Example 3, the molar extinction coefficient is 33,500 dm ³ mol ^-1 cm ^-1 or more at 470 nm, compared to the conventional metal complex Has a significantly higher value. The molar extinction coefficient is an important variable in improving the photoelectric conversion efficiency of the solar cell. 3 shows an IPCE curve of a solar cell manufactured using the dye compound 3, and has a high conversion efficiency of 70.6% in the 475 nm wavelength region.

Claims (9)

Dye-sensitized solar cell dye having a structure of formula (1).
[Formula 1]

Wherein D ₁ and D ₂ are either phenyl groups, alkyl groups having 1 to 10 carbon atoms, or phenyl groups substituted with alkoxy groups, C is any one of benzene and vinylbenzene, and B is benzene, furan, thiophene, pyrrole Is any one selected from among aromatic heterocyclic groups, and A is a carboxy group) delete delete delete delete The dye-sensitized solar cell dye according to claim 1, wherein the dye is a compound having a structure of Formula 2 below.
(2)

The dye-sensitized solar cell dye of claim 1, wherein the dye is a compound represented by the following Chemical Formula 3.
(3)

The dye-sensitized solar cell dye according to claim 1, wherein the dye is a compound represented by the following Chemical Formula 4.
[Chemical Formula 4]

Dye-sensitized solar cell device using the dye of claim 1.

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