KR101323866B1

KR101323866B1 - Noble photosensitizer for photovoltaic cell and photovoltaic cell prepared from the same

Info

Publication number: KR101323866B1
Application number: KR1020110063890A
Authority: KR
Inventors: 김복영; 안중복; 박노길; 한근희
Original assignee: (주)씨에스엘쏠라
Priority date: 2011-04-29
Filing date: 2011-06-29
Publication date: 2013-10-31
Also published as: KR20120122849A

Abstract

The present invention relates to novel ruthenium-based dyes used as dyes in dye-sensitized solar cells and dye-sensitized solar cells prepared therefrom.
The dye according to the present invention exhibits a markedly improved photovoltaic conversion efficiency, a bond with oxide semiconductor fine particles, a dye-sensitized photoelectric conversion device having excellent short circuit photocurrent density (Jsc) and a molar extinction coefficient, and a solar cell having a markedly improved efficiency. Contribute to the offering.

Description

Novel dye-sensitized solar cell dyes and dye-sensitized solar cells produced therefrom {NOBLE PHOTOSENSITIZER FOR PHOTOVOLTAIC CELL AND PHOTOVOLTAIC CELL PREPARED FROM THE SAME}

The present invention relates to novel ruthenium-based dyes used as dyes in dye-sensitized solar cells and dye-sensitized solar cells prepared therefrom.

Much research has been done in this area since the development of dye-sensitized nanoparticle titanium dioxide solar cells by Michael Gratzel of the Swiss National Lozan Institute for Technology (EPFL) in 1991. Dye-sensitized solar cells have the potential to replace conventional amorphous silicon solar cells because their manufacturing costs are significantly lower than conventional silicon-based solar cells. Unlike silicon solar cells, dye-sensitized solar cells absorb visible light It is a photoelectrochemical solar cell whose main constituent material is a dye molecule capable of generating hole pairs and a transition metal oxide that transfers generated electrons.

Typical dyes used in dye-sensitized solar cells include the following compounds.

However, it is still required to increase the efficiency and durability of solar cells by increasing the bonding force with the oxide semiconductor fine particles, the photoelectric conversion efficiency, the shortcircuit photocurrent density (Jsc) and the molar extinction coefficient compared to the above dyes. Is needed

In order to solve the problems of the prior art as described above, the present invention shows a remarkably improved photoelectric conversion efficiency than the conventional dye, enhances the bonding force with the oxide semiconductor fine particles, JSC (short circuit photocurrent density) and the molar extinction coefficient is excellent It is an object of the present invention to provide a dye and a method for producing the same that can greatly improve the efficiency of a solar cell.

In addition, the present invention exhibits a remarkably improved photoelectric conversion efficiency, including the dye, the bonding strength with the oxide semiconductor fine particles, the dye-sensitized photoelectric conversion element and excellent efficiency of the short circuit photocurrent density (Jsc) and the molar extinction coefficient is significantly improved It aims to provide solar cell

Dyes for dye-sensitized solar cells and dye-sensitized solar cells according to the present invention include compounds having the structure of Formula F:

In the above formula (F)

R1 and R2 are each independently of the formula F1 or F2

In each of Formulas F1 and F2

n is 0 (zero), 1, 2 or 3,

A is H, D, F, C1-C40 alkyl group, C5-C40 aryl group, C3-C40 heteroaryl group, C5-C40 aryloxy group, C1-C40 alkyloxy group, C5-C40 aryl An amino group, a C5 to C40 diarylamino group, a C6 to C40 arylalkyl group, a C3 to C40 cycloalkyl group, and a C3 to C40 heterocycloalkyl group; Or adjacent groups to form a fused aliphatic ring, a fused aromatic ring, a fused heteroaliphatic ring, or a fused heteroaromatic ring.

In addition, the dye for the dye-sensitized solar cell and the dye-sensitized solar cell according to the present invention according to the present invention is based on the compound represented by the following formula (1).

The novel dyes and dye-sensitized solar cells prepared therefrom exhibit significantly improved photovoltaic conversion efficiencies, enhance bonding with oxide semiconductor particulates, and have excellent short circuit photocurrent density (Jsc) and molar extinction coefficients. The efficiency of the battery can be greatly improved.

Hereinafter, the present invention will be described in detail.

The present invention may be modified in various ways and may have various forms, and thus embodiments (or embodiments) will be described in detail in the text. However, this is not intended to limit the present invention to the specific form disclosed, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present application, the term " comprising " or " consisting of ", or the like, refers to the presence of a feature, a number, a step, an operation, an element, a component, But do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

Dyes for dye-sensitized solar cells according to the present invention include compounds having the structure of Formula F:

In the above formula (F)

R1 and R2 are each independently of the formula F1 or F2

In each of Formulas F1 and F2

n is 0 (zero), 1, 2 or 3,

The inventors of the present invention select R1 and R2 from the compound represented by Formula F, respectively, and develop a ruthenium-based dye substituted with specific various derivatives, specifically, ruthenium-based dyes, thiazole-based derivatives, and applied them to solar cells. The results show that the photoelectric conversion efficiency is significantly improved, and the short circuit photocurrent density (Jsc) and the molar extinction coefficient are improved.

In F, R1 and R2 are the same functional group,

In each of Formulas F1 and F2 n is 0 (zero), 1 or 2,

A is preferably H, D, F or a C1-C40 alkyl group.

When n is 0 (zero) in each of Formulas F1 and F2 in relation to the following Compounds 1 to 9, Compounds 1, 2, and 7 are n, and Compounds 3, 4 and 8 are n, and n is 2. Is compound 5, 6, 9.

In each of Formulas F1 and F2, each of C1 to C40 alkyl group, C5 to C40 aryl group, C3 to C40 heteroaryl group, C5 to C40 aryloxy group, C1 to C40 alkyloxy group, and C5 to C40 arylamino group, C5 ~ C40 diarylamino group, C6 ~ C40 arylalkyl group, C3 ~ C40 cycloalkyl group and C3 ~ C40 heterocycloalkyl group

Deuterium, halogen, nitrile group, nitro group, C1-C40 alkyl group, C2-C40 alkenyl group, C1-C40 alkoxy group, C1-C40 amino group, C3-C40 cycloalkyl group, C3-C40 It is preferably substituted or unsubstituted with one or more selected from the group consisting of a heterocycloalkyl group, an aryl group of C6 to C40, a heteroaryl group of C5 to C40, and a silane group.

C1-C40 alkyl group of C, C5-C40 aryl group, C3-C40 heteroaryl group, C5-C40 aryloxy group, C1-C40 alkyloxy group, C5-C40 arylamino group, C5- In the substituent introduced into C40 diarylamino group, C6-C40 arylalkyl group, C3-C40 cycloalkyl group, and C3-C40 heterocycloalkyl group

C1-C40 alkyl group, C1-C40 amino group, C3-C40 cycloalkyl group, C3-C40 heterocycloalkyl group, C6-C40 aryl group, and C5-C40 heteroaryl group

A substituted or unsubstituted C1 to C40 alkyl group, a substituted or unsubstituted C1 to C40 alkoxy group, a substituted or unsubstituted C1 to C40 amino group, a substituted or unsubstituted C3 to C40 cycloalkyl group, At least one second substituent selected from the group consisting of a heterocycloalkyl group of C40, an aryl group of C6 to C40, and a heteroaryl group of C5 to C40; Or to form adjacent condensed aliphatic rings, condensed aromatic rings, condensed heteroaliphatic rings or condensed heteroaromatic rings or spiro bonds.

Furthermore, said C1-C40 alkyl group of said A, C5-C40 aryl group, C5-C40 heteroaryl group, C5-C40 aryloxy group, C1-C40 alkyloxy group, C5-C40 arylamino group, C5 Substituents which are introduced into a diarylamino group of -C40, an arylalkyl group of C6-C40, a cycloalkyl group of C3-C40, and a heterocycloalkyl group of C3-C40 are

A phenanthryl group, a phenanthryl group, an anthracenyl group, a benzoanthracenyl group, an azranyl group, an acenaphthylenyl group, a phenanthryl group, a phenanthryl group, a phenanthryl group, A phenanthryl group, a phenanthrenyl group, a phenanthrenyl group, a phenanthrenyl group, a pyrenyl group, a chrysenyl group, a picenyl group, a perylenyl group, a chloroperylenyl group, a pentaphenyl group, A phenyl group, a hexacenyl group, a rubicenyl group, a coronenyl group, a trinaphthylenyl group, a heptaphenyl group, a heptacenyl group, a fluorenyl group, a pyranthrenyl group, an obenyl group, a carbazolyl group, a dibenzofuranyl group, A thiophenyl group, a thiophenyl group, an indolyl group, a purinyl group, a benzimidazolyl group, a quinolizinyl group, a quinolinyl group, a benzothiophenyl group, a parathiazinyl group, a pyrrolyl group, a pyrazolyl group, an imidazolyl group, , Thiazolyl group, triazolyl group, tetrazolyl group, oxadiazolyl group, A pyridinyl group, a pyridazinyl group, a pyrimidinyl group, a pyrazinyl group, a thianthrenyl group, a cyclopentyl group, a cyclohexyl group, an oxiranyl group, a pyrrolidinyl group, a pyrazolidinyl group, (C6-C50 aryl) amino group, silyl group, and derivatives thereof are preferable.

The aryl group is a monovalent group having an aromatic ring system and may include two or more ring systems, and the two or more ring systems may exist in a bonded or condensed form to each other. The heteroaryl group refers to a group in which at least one carbon of the aryl group is substituted with at least one member selected from the group consisting of N, O, S, P, Si and Se.

On the other hand, the cycloalkyl group refers to an alkyl group having a ring system, and the heterocycloalkyl group refers to a group in which at least one carbon in the cycloalkyl group is substituted with at least one member selected from the group consisting of N, O, S, P, Si and Se .

When at least one hydrogen of the aryl group and the heteroaryl group is substituted, the substituent is a C1-C50 alkyl group; A C1-C50 alkoxy group; A C6-C50 aryl group unsubstituted or substituted with a C1-C50 alkyl group or a C1-C50 alkoxy group; A C2-C50 heteroaryl group unsubstituted or substituted with a C1-C50 alkyl group or a C1-C50 alkoxy group; A C5-C50 cycloalkyl group which is unsubstituted or substituted by a C1-C50 alkyl group or a C1-C50 alkoxy group and a C5-C50 heterocycloalkyl group which is unsubstituted or substituted by a C1-C20 alkyl group or a C1-C20 alkoxy group, &Lt; / RTI >

The present invention also provides a first electrode comprising a substrate having conductivity and light transmittance, a light absorbing layer formed on one surface of the first electrode, a second electrode disposed opposite to the first electrode on which the light absorbing layer is formed, and the first electrode. An electrolyte disposed between the first electrode and the second electrode, wherein the light absorbing layer comprises a semiconductor fine particle, and the dye provides a dye-sensitized solar cell.

In dye-sensitized solar cells, the first step in driving solar cells is the process of generating photocharges from light energy. Typically, a dye material is used to generate photocharges, and the dye material is excited by absorbing light transmitted through the conductive transparent substrate.

When sunlight enters the dye-sensitized solar cell, the photons are absorbed by the dye molecules in the light absorbing layer, whereby the dye molecules electron-transfer from the ground state to the excited state to form electron-hole pairs. Electrons in the excited state are injected into the conduction band of the semiconductor fine particle interface, and the injected electrons are transferred to the first electrode through the interface. After that, it moves to the second electrode which is the counter electrode through the 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 layer, and the oxidized ions undergo a reduction reaction with the electrons reaching the interface of the second electrode to achieve charge neutrality. The dye-sensitized solar cell is thereby operated.

As the first electrode, any conductive transparent substrate having conductivity and transparency (more broadly transmissive) can be used without particular limitation.

The light absorbing layer includes semiconductor fine particles and a dye according to one embodiment of the present invention in which electrons are excited by absorbing visible light and absorbed by the semiconductor fine particles.

The semiconductor fine particles may be a metal oxide or a composite metal oxide having a perovskite structure, in addition to the single 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. Specifically, the semiconductor fine particles include Si, TiO 2, SnO 2, ZnO, WO 3, Nb 2 O 5, TiSrO 3, and the like, and more preferably, anatase type TiO 2 may be used.

On the other hand, the dye-sensitized solar cell dye according to the present invention can be represented by the formula F, and more specifically, the formula F is represented by the following formula 1 to 9 (in the following formulas ('formula' is omitted in the formulas, only numbers)) Can be expressed.

Hereinafter, the reaction examples and examples of the present invention are specifically illustrated, but the present invention is not limited to the following reaction examples and examples. In the following reaction, the intermediate compound is indicated by adding a serial number to the number of the final product. For example, compound 1 is represented by compound [1], and the intermediate compound of the said compound is described by [1-1] etc.

In the present specification, the chemical number is indicated as the chemical formula number. For example, the compound represented by the formula (1) is represented by compound 1.

[Reaction Example 1] Preparation of compound [1]

Preparation of Intermediate Compounds [1-1] and [1-2]

10.0 g (33.33 mmol) of 2,5-dibromothiazolo [5,4-d] thiazole was dissolved in 200 mL of tetrahydrofuran under a nitrogen stream in a 500 mL reaction flask, and 16 mL (40.0 mL) of 2.5M butyllithium at -78 ° C. mmol) was added dropwise. After stirring for 10 minutes at the same temperature, 10.8 mL (40.0 mmol) of tributyltin chloride was added dropwise. After heating up to room temperature for 12 hours, the organic layer obtained by layer separation with ethyl acetate and saturated aqueous ammonium solution was removed with anhydrous magnesium sulfate and distilled under reduced pressure. The intermediate compound [1-1] was vacuum dried, and then dissolved in 300 mL of dimethylformamide in a reaction flask, and 3.05 g (9.72 mmol) of 4,4'-dibromo-2,2'-bipyridine and tetrakis triphenylphosphine palladium were dissolved. 561 mg (0.486 mmol) was added under nitrogen atmosphere and stirred under reflux for 3 hours. The reaction solution is cooled to room temperature, and then separated by ethyl acetate / ammonium saturated aqueous solution. The organic layer was washed three times with saturated brine, dried over anhydrous magnesium sulfate and filtered. The filtrate was concentrated under reduced pressure and purified by column chromatography to prepare 3.5g (82%) of the intermediate compound [1-2].

Preparation of compound [1]

In a 250 mL reaction flask, 1.0 g (3.266 mmol) of ruthenium dichloro (para-cymen) dimer and 1.35 g (3.103 mmol) of the intermediate compound [1-2] are suspended and stirred with 100 mL of dimethylformamide. After stirring at 80 ° C. for 4 hours, 757 mg (3.103 mmol) of 2,2′-bipyridine-4,4′-dicarboxylic acid were added thereto. After stirring for 4 hours at reflux, 6.22 g (81.65 mmol) of ammonium thiocyanate was added. After the reaction temperature was stirred at 130 ° C. for 4 hours, the reaction solution was filtered by cooling to room temperature. The filtrate was concentrated under reduced pressure and washed with 100 mL of purified water and 100 mL of methanol. The solid is dissolved in tetrabutylhydroxy ammonium salt methanol solution and separated and purified by column chromatography (eluate methanol) using Sephadex LH-20. The collected solution was acidified with dilute methanolic nitrate solution to prepare 1.5 g (40%) of the title compound [1] as a dark reddish solid.

[Reaction Example 2] Preparation of Compound [7]

Preparation of Intermediate Compound [7-1]

10.0 g (33.33 mmol) of 2,5-dibromothiazolo [5,4-d] thiazole was dissolved in 200 mL of tetrahydrofuran under a nitrogen stream in a 500 mL reaction flask, and 14.7 mL of 2.5 M butyllithium at -78 ° C. 36.66 mmol) was added dropwise. After stirring for 10 minutes at the same temperature, 7.07 mL (40.93 mmol) of bromooctane was added dropwise. After heating up to room temperature for 8 hours, the organic layer obtained by layer separation with ethyl acetate and saturated aqueous ammonium solution was removed with anhydrous magnesium sulfate and distilled under reduced pressure. The concentrated solution was purified by silica gel column chromatography to prepare 4.7 g (42%) of an intermediate compound [7-1].

Preparation of Intermediate Compound [7-2]

4.5 g (13.5 mmol) of the intermediate compound [7-1] were dissolved in 100 mL of tetrahydrofuran under a nitrogen stream in a 250 mL reaction flask, and 6.48 mL (16.2 mmol) of 2.5M butyllithium was added dropwise at -78 ° C. After stirring for 10 minutes at the same temperature, 1.25 mL (16.2 mmol) of dimethylformamide was added dropwise. After heating up to room temperature for 8 hours, the organic layer obtained by layer separation with ethyl acetate and saturated aqueous ammonium solution was removed with anhydrous magnesium sulfate and distilled under reduced pressure. The concentrate was separated and purified through silica gel column chromatography to obtain 2.5 g (65%) of an intermediate compound [7-2].

Preparation of Intermediate Compound [7-3]

In a 250 mL reaction flask, 2.5 g (8.85 mmol) of an intermediate compound [7-2] and 1.84 g (4.02 mmol) of tetraethyl 2,2'-bipyridine-4,4'-diylbis (methylene) diphosphonate were added to anhydrous tetra. It is stirred in 100 mL of hydrofuran in a nitrogen atmosphere. 2.48 g (22.13 mmol) of tert-butoxy potassium are added at 5 ° C. After stirring at the same temperature for 1 hour, the reaction solution was separated by ethylacetate and saturated aqueous ammonium solution, and the organic layer was dried with anhydrous magnesium sulfate and distilled under reduced pressure. The concentrate was separated and purified through silica gel column chromatography to prepare 1.8 g (28%) of an intermediate compound [7-3].

Preparation of Compound [7]

Ruthenium dichloro (para-cymene) dimer, intermediate compound [4-2], 2,2'-bipyridine-4,4'-dicarboxylic acid and thiocyanic acid were prepared in the same manner as in the method for preparing compound [1]. To prepare the desired compound [7] as a burgundy solid.

Compounds 1 to 9 were prepared in the same manner as in Reaction Examples 1 and 2, and the results are shown in the following [Table 1].

[Table 1]

Comparative Example 1: Preparation of Dye-Sensitized Solar Cell

A titanium oxide dispersion having a particle size of 5 to 15 nm on a fluorine-doped tin oxide (FTO) was applied to a ² cm ² area by a doctor blade method, and a porous titanium oxide thick film having a thickness of 20 μm was formed through a heat-treatment calciner at 450 ° C. for 30 minutes. Produced. Thereafter, the specimen was immersed in a dye dispersion solution of Comparative Sample 1 dissolved in ethanol at a concentration of 0.3 mM at room temperature, and then the dye adsorption treatment was performed for 24 hours or more.

Thereafter, the porous titanium oxide thick film to which the dye was adsorbed was washed with ethanol and dried at room temperature to prepare a first electrode having a light absorption layer.

A platinum layer was formed to a thickness of about 200 nm on a fluorine-doped tin oxide (FTO) by screen printing, and a second electrode was prepared by making two micropores using a 0.75 mm diameter drill for electrolyte injection.

Next, the first electrode and the second electrode were disposed with a polymer partition wall having a thickness of about 40 to 60 μm made of SURLYN (thermoplastic polymer film), and then pressed at about 1 to 2 atm on a heating plate of about 150 ° C. A sealed space is formed between the first electrode and the second electrode.

0.6M 1-hexyl-2,3-methyl-imidazolium iodide, 0.1M LiI, 0.05MI ₂ and 0.5M 4-tert-butyl-pyridine (TBP) were injected into the micropores of the second electrode. A solar cell was prepared by injecting an electrolyte solution of I ₃ / I dissolved in a reel.

Evaluation Example: Comparative Sample 1

The photocurrent voltage of the dye-sensitized solar cell manufactured in Comparative Example 1 was measured, and an open-circuit voltage (Voc), a short-circuit current (Jsc), and a fill factor were measured from the measured photocurrent curve. : FF) was calculated and the light conversion efficiency was calculated using the above values.

In this case, a xenon lamp (xenon lamp, Newport, 66142 500W) was used as the light source, and the solar condition (AM 1.5) of the xenon lamp was a standard solar cell (National Renewable Energy Laboratory, A2LA accreditation certificate # 2236.01, Type of material: Mono -Si + BK7 filter).

The current density Is, the voltage Voc, the fill factor (FF), and the photoelectric conversion efficiency (η) calculated therefrom are shown in the following [Table 2].

[Table 2]

Example 1 Preparation of Dye-Sensitized Solar Cells

A titanium oxide dispersion having a particle size of 5 to 15 nm on a fluorine-doped tin oxide (FTO) was applied to a ² cm ² area by a doctor blade method, and a porous titanium oxide thick film having a thickness of 20 μm was formed through a heat-treatment calciner at 450 ° C. for 30 minutes. Produced. Thereafter, the specimens were immersed in a dye dispersion in which the following Chemical Formulas 1 to 62 were dissolved in ethanol at a concentration of 0.3 mM, and then the dye adsorption treatment was performed for 24 hours or more.

Evaluation Example: Evaluation of Properties of Chemical Formulas 1 ~ 9

The photocurrent voltages of the dye-sensitized solar cells prepared in Examples 1 to 9 were measured, and an open-circuit voltage (Voc), a short-circuit current (Jsc) and a filling factor (from the measured photocurrent curve) were measured. fill factor (FF) was calculated, and the light conversion efficiency was calculated using the above values.

The current density (Isc), voltage (Voc) and fill factor (FF) and photoelectric conversion efficiency (η) calculated therefrom are shown in the following [Table 3].

[Table 3]

<Evaluation Example 2>

&Lt; Evaluation Example 6 &

In the above description, the conventional well-known technique is omitted, but a person skilled in the art can easily guess, deduce and reproduce it.

Claims

Dyes for dye-sensitized solar cells comprising a compound having the structure of Formula F:
<Formula F>

In Formula F
R1 and R2 are each independently of the formula F1 or F2
<Formula F1><FormulaF2>

In each of Formulas F1 and F2
n is 0 (zero), 1, 2 or 3,

A is H, D, F, C1-C40 alkyl group, C5-C40 aryl group, C3-C40 heteroaryl group, C5-C40 aryloxy group, C1-C40 alkyloxy group, C5-C40 aryl An amino group, a C5 to C40 diarylamino group, a C6 to C40 arylalkyl group, a C3 to C40 cycloalkyl group, and a C3 to C40 heterocycloalkyl group; Or adjacent groups to form a fused aliphatic ring, a fused aromatic ring, a fused heteroaliphatic ring, or a fused heteroaromatic ring.

The method of claim 1,
D in the dye-sensitized solar cell, characterized in that R in the F and R2 are the same functional groups.

3. The method of claim 2,
In each of Formulas F1 and F2
n is 0 (zero), 1 or 2,
A is a dye for a dye-sensitized solar cell, wherein an alkyl group is H, D, F, or C 1 -C 40.

The method of claim 1,
Chemical Formula F is a dye-sensitized solar cell dye, characterized in that represented by any one of the following Formulas 1 to 9:

A first electrode comprising a substrate having conductivity and light transmission;
A light absorbing layer formed on one surface of the first electrode;
A second electrode disposed to face the first electrode on which the light absorption layer is formed; And
An electrolyte located between the first electrode and the second electrode,
The light-sensing layer is a dye-sensitized solar cell comprising a semiconductor fine particle, and the dye according to any one of claims 1 to 4.