TW201333122A - Dye compounds, method of making the same, and their use in dye-sensitized solar cells - Google Patents

Abstract

Disclosed are novel dye compounds, method of making them, and their use in photoelectric conversion devices, especially in dye-sensitized solar cells. The dye compounds are organometallic compounds of formula ML1L2, wherein L1 and L2 independently indicates a tridentate ligand of specific structures.

Description

Dye compound, preparation method thereof and use thereof in dye-sensitized solar cell

The present application claims priority to European Patent Application No. 1119016, filed on Nov. 22, 2012, the entire disclosure of which is hereby incorporated by reference.

The present invention relates to novel dye compounds, methods of making same, and their use as dyes in photoelectric conversion devices, particularly dye sensitized solar cells (DSSC).

Conventional solar cells convert light into electricity using the photoelectric effect present at the junction of the semiconductor. In other words, these commercial solar cells absorb energy from visible light and convert their excited carriers into electrical energy. Currently, these commercial solar cells are mainly silicon-based solar cells. For the bismuth-based solar cell, there are disadvantages in that high energy costs are required for material processing and there are many problems to be solved, such as environmental burden and cost and material supply limitations. For an amorphous germanium solar cell, there is also a drawback in that energy conversion efficiency is lowered when the battery is used for a long period of time due to deterioration in a short period of time.

Recently, many attempts have been made to develop low-cost organic solar cells. In particular, the goal of development has been directed to dye-sensitized solar cells (DSSCs) based on a semiconductor sensitized electrode, a counter electrode, and an electrolyte. The photosensitizer absorbs incident light Generate excited electrons.

An example of a ruthenium complex used as a dye molecule in a dye-sensitized solar cell is the dye "N719" or [Ru(NCS) ₂ (dcbpy) ₂ ] (dcbpy = 4,4'-dicarboxy-2,2' -bipyridyl), and "N749" or "black dye" ie [Ru(NCS) ₃ (tctpy)](tctpy=4,4',4"-tricarboxylic acid-2,2':6',2" -tripyridinium). Although these DSSCs using the dye N719 exhibit high conversion efficiencies, they are insufficient in durability such as weather resistance and heat resistance. Alternatively, higher efficiencies can still be achieved with black dyes. However, the black dye cannot replace N719 due to the following disadvantages, for example, it is difficult to synthesize, form an isomer, a low extinction coefficient, and troublesome battery manufacture due to coalescence or the like.

Recently, the use of cyclometallated rhodium complexes in place of N719 and black dyes has been reported as an effective photosensitizer for TiO ₂ semiconductor electrodes for solar cells (see, for example, [Sipke H. Wadman et al., Chemical Communications [Chem. Commun.], 2007, 1907-1909]). It discloses the use of a ring-metallated rhodium complex of the [Ru(C^N^N)(N^N^N)] configuration. EP 2,036,955 A1 also discloses dyes containing bidentate and tridentate ligands having a specific structure, for example, dyes as shown below, DSSCs comprising such dyes, and methods for making such dyes.

The present invention now produces improvements for DSSCs, particularly useful dyes that improve absorption range and/or stability. More specifically, the present invention provides dyes that exhibit a broad absorption spectrum (i.e., absorb as much solar spectrum as possible), a high molar extinction coefficient, and/or contribute to the long-term stability of the device.

It is an object of the present invention to provide novel dyes which exhibit advantageous properties when applied in photoelectric conversion devices, particularly dye sensitized solar cells (DSSC).

Accordingly, the present invention relates to a dye compound of the following formula (I): ML1L2 (I)

Wherein M represents a metal belonging to Group 6, 8, 9, 10, or 11 in the long-format Periodic Table; L1 and L2 are independently selected from tridentate ligands, L1 and L2 At least one of the following formulas (T): Aa-Ab-Ac (T)

Wherein Aa, Ab, and Ac are each an aromatic group, and Aa is bonded to M by a metal-carbon bond, Ab is attached to M by a metal-nitrogen bond (MN), and Ac is supported by a metal The -X bond is attached to M, wherein X is selected from C and N, and the dye compound of formula (I) has two carbon-metal bonds.

Typically, the Ab is attached to Aa or Ac in the ortho position relative to a nitrogen atom forming part of the aromatic group Ab, and the nitrogen atom forms the metal-nitrogen bond. Preferably, the Ab is attached to Aa and Ac in the ortho position relative to the nitrogen atom.

In a preferred embodiment, at least one of L1 and L2 conforms to the following chemical formula (II):

Wherein X is selected from C and N, and R1, R1', R1", and R1"' are independently selected from the group consisting of hydrogen, halogen, cyano, and alkyl groups, alkoxy groups An aryl group, an aryloxy group, a heterocyclic ring, an amine group, and a halogenated derivative thereof, and R3 is selected from the group consisting of hydrogen, halogen, cyano, and an alkyl group, An alkoxy group, an aryl group, an aryloxy group, a heterocyclic ring, an amine group, and a halogenated derivative thereof, NO ₂ , and an anchoring group, if the X system is C, R2, R2', R2", and R2"' are independently selected from the group consisting of hydrogen, halogen, cyano, and alkyl groups, alkoxy groups, aryl groups, aryloxy groups a radical, a heterocyclic ring, an amine group, and a halogenated derivative thereof, NO ₂ , and an anchor group, or if X is N, then R 2 , R 2 ', R 2 ′′, and R 2 ′′ are independently selected from Groups of hydrogen, halogen, NO ₂ , and anchor groups.

The dye compounds of the invention are suitable for use in photoelectric conversion devices, particularly in semiconductor layers of dye sensitized solar cells (DSSC). Thus, the present invention also relates to a dye compound of the present invention or a salt thereof Application in photoelectric conversion devices, especially in DSSCs.

The dyes of the invention are metal complexes having two tridentate ligands which are composed of three aromatic rings and are therefore conjugated. Also, the dye compounds of the present invention have two carbon-metal bonds in which the carbon atoms are present on the terminal side of the tridentate ligand. These carbon atoms in the benzene ring have stronger electron donating properties than the NCS ligand and thus contribute to an increase in electron density at the metal center.

The dyes of the invention may have a broad absorption spectrum, particularly in the visible and near infrared regions, i.e., absorb as much light as possible. The dyes of the invention may also exhibit a high molar extinction coefficient. Such dyes can have improved electron transport and directionality as electrons are transferred from the photosensitizer to the semiconductor electrode. And because of the absence of monodentate thiocyanate ligands, such dyes can also contribute to the long-term stability of such devices, such as better tolerance to substitutions induced by trace amounts of water in such devices, and It is better to protect the photoelectrode from corrosion by components present in the electrolyte such as the triiodide/iodide pair.

In a preferred embodiment of the invention, the dye compounds of formula (I) have two carbon-metal bonds, wherein the carbon atoms are located at the terminal positions of the tridentate ligands such that they are located at the anchor group The trans position. This configuration provides better directionality for electrons in the excited state of the photosensitizer.

In the present invention, "alkyl group" is understood to mean specifically a straight, branched, or cyclic hydrocarbon group generally having from 1 to 20 carbon atoms. group. Examples of the alkyl group include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, secondary butyl, tert-butyl, pentyl, neopentyl, hexyl, cyclopropyl, Cyclobutyl, cyclopentyl, and cyclohexyl.

In the present invention, "alkoxy group" is understood to mean specifically a straight-chain, branched, or cyclic hydrocarbon group generally having from 1 to 20 carbon atoms bonded to an oxygen by a single bond. Group (Alk-O-).

In the present invention, "aryl group" is understood to specifically mean any functional group or substituent derived from one aromatic ring. In particular, the aryl group may have 6 to 20 carbon atoms (since it is easily synthesized at low cost, preferably 6 to 12), wherein some or all of the hydrogen atoms of the aryl group may be or It is not substituted by other groups, especially alkyl groups, alkoxy groups, or hydroxyl groups. Preferably, the aryl groups are optionally substituted with phenyl groups, naphthyl groups, mercapto groups, and phenanthryl groups. A particular aryl group in the present invention is an alkoxy-substituted phenyl group such as a phenyl group whose ortho and para positions are substituted by an alkoxy group.

In the present invention, "aryloxy group" is understood to mean, in particular, an aryl group (Ar-O-) as defined above which is bonded to an oxygen by a single bond.

In the present invention, "heterocyclic" is understood to mean, in particular, a cyclic compound having at least one heteroatom as a constituent member of one or more of its rings. Common heteroatoms within the ring include sulfur, oxygen, and nitrogen. The heterocyclic ring may be saturated or unsaturated and may be a three-membered ring, a four-membered ring, a five-membered ring, a six-membered ring, or a seven-membered ring. The heterocyclic ring can be further fused to one or more other ring systems. Examples of the heterocyclic ring include pyridyl Rectanes, oxolanes, thiolanes, pyrroles, furans, thiophenes, acridines, oxiranes, thiane sulfides, pyridines, pyridyls Carbens, and thiopyrans, and their derivatives. A particular class of such heterocyclic species includes substituents containing thiophene moieties.

In the present invention, "a substituent group containing a thiophene moiety" is understood to specifically refer to a substituent group including a thiophene ring or a plurality of thiophene rings. The substituents including a thiophene ring may further include other one or more rings attached to the thiophene ring, such as 3,4-ethylenedioxythiophene (EDOT), and/or may be subjected to other groups, such as Substituted by alkyl groups or alkoxy groups. Moreover, the substituent including the thiophene ring may be substituted by an aryl group or an aryloxy group, and the aryl group or the aryloxy group may be optionally an alkyl group or an alkoxy group. Substituent substitution. The substituents including a plurality of thiophene rings include oligothiophenes wherein the plurality of thiophene rings are linked by one or more single bonds (eg, mono, di, tri, and tetrathiophene), or wherein The thiophene ring is fused (eg, [n] thienoacene ([n] thienoacenes) (where n is an integer from 2 to 7) or [n] thiophene olefin ([n] thienohelicenes) (where n An integer from 2 to 7)), and an oligothiophene fused to one or more rings different from the thiophene ring, such as phenyl-thiophene, thiazole-thiophene, or cyclopentadiene-thiophene alternating molecule . The oligothiophenes may be further substituted with other groups such as alkyl groups or alkoxy groups. The substituents may be any combination of the same or different substituents. Non-limiting examples of substituents including a thiophene moiety include at least one structure selected from the group consisting of: Wherein R independently represents an alkyl group or an alkoxy group.

In the present invention, "amino group" is understood to mean specifically an aliphatic amine or an aromatic amine and encompasses a compound including one or more amine groups. The amine group may be a primary amine, a secondary amine, and a tertiary amine, wherein one or more hydrogen atoms may or may not be blocked by other groups such as an alkyl group or an aryl group. Class substitution. The one or more hydrogen atoms may be substituted by an alkyl group or an aryl group, and the aryl groups are further substituted by other groups such as an alkyl group or an alkoxy group.

In the present invention, "halogenated derivative" is understood to mean specifically that at least one hydrogen atom has been substituted by a halogen atom, preferably the halogen atom is selected from fluorine and chlorine, more preferably fluorine. . If all of the hydrogen atoms have been replaced by a halogen atom, the halogenated derivative is a perhalogenated derivative. For example, halogenated derivatives of alkyl groups include (per)fluorinated alkyl groups such as (per)fluorinated methyl, ethyl, propyl, isopropyl, butyl, isobutyl , a secondary butyl group, or a tertiary butyl group; for example, -CF ₃ , -C ₂ F ₅ , heptafluoroisopropyl (-CF(CF ₃ ) ₂ ), or hexafluoroisopropyl (-CH (CF _{3 )} ) ₂ ).

In the present invention, "anchoring group" is understood to mean, in particular, a group which will allow the dye to adhere to a semiconductor such as TiO ₂ . Suitable anchor groups selected from, but not limited to, for example, the group consisting _{of: -COOH, -PO 3 H 2,} -PO 4 H 2, -SO 3 H, -CONHOH, acetylation acetonide, acrylic Derivatives, malonic acid derivatives, rosin-3-acetic acid, propionic acid, such deprotonated forms, salts of the deprotonated form, and chelating groups having π-conducting properties More preferred are -COOH and deprotonated salts of -COOH. Particularly preferred salts of -COOH are, for example, ammonium salts or alkali metal salts, more preferably -COOTBA (wherein TBA represents tetrabutylammonium). In the sense of the present invention, the dye compounds of the invention may comprise at least one anchoring group. In particular, the dye compounds of the invention may comprise at least two anchoring groups, for example two or four anchoring groups.

The dye compounds of the present invention have the following chemical formula (I): ML1L2 (I) wherein the dye compound of the formula (I) has two carbon-metal bonds.

In the present invention, M is a metal atom belonging to Group 6, 8, 9, 10, or 11 of the long-form periodic table. Preferred elements are iron, ruthenium, osmium, iridium, cobalt, palladium, platinum, and chromium. Particularly preferred is a dye compound having one atom as the M. Generally, ML1L2 is a hexacoordinated complex, particularly an octahedral complex having M as a central atom.

In the present invention, L1 and L2 are independently selected from a tridentate ligand, and at least one of L1 and L2 conforms to the following chemical formula (T): Aa-Ab-Ac (T)

In the present invention, each of Aa, Ab, and Ac is an aromatic group. Preferred aromatic groups are phenyl groups or pyridine groups. In the present invention, Aa is bonded to M via a metal-carbon bond and is preferably a phenyl group, and Ab is attached to M via a metal-nitrogen bond and is particularly a pyridyl group. In the present invention, since X is selected from C and N, Ac is bonded to M by a metal-carbon bond or a metal-nitrogen bond.

In a specific embodiment, Aa and Ab are linked by a bond at their position 2 at the atom of one atom which contributes to the formation of a metal-carbon bond and a metal-nitrogen bond in the aromatic group. Between each atom. In the case where both Aa and Ab are 6-membered aromatic rings, such as a benzene ring or a pyridine ring, Aa and Ab are linked by a bond formed at each ortho position of the rings. Further, Ab and Ac are linked by a bond at a position on the 2 position of the atom which contributes to the formation of the M-X bond in Ac. The aromatic group is between the atom at the 2 position of one atom of the metal formed and the other atom at the nearest position. For example, if Ab is a 6-membered aromatic ring, such as a pyridine ring, another atomic system at the nearest position is located at one of the 6-position atoms. In the case where both Ab and Ac are 6-membered aromatic rings, if the 2 positions of Ab are occupied for attachment to Aa, then Ab and Ac are linked by a bond between the 2 position of Ac and the 6 position of Ab. .

In a specific embodiment of the invention, L1 and L2 are independently selected from a tridentate ligand, and at least one of L1 and L2 conforms to the following chemical formula (II): Wherein R1, R1', R1", and R1"' are independently selected from the group consisting of hydrogen, halogen (especially fluorine and chlorine), cyano, and alkyl groups, alkoxy groups An aryl group, an aryloxy group, a heterocyclic ring, an amine group, and a halogenated derivative thereof.

Preferably, R1, R1', R1", and R1"' are independently selected from the group consisting of hydrogen, halogen (such as chlorine and fluorine), alkoxy groups such as OCH ₃ , and aryloxy a group such as OPh, a halogenated alkyl group such as C ₆ F ₅ , CF ₃ , and CH ₃ (CF ₂ ) ₃ CF ₃ , and a substituent including a thiophene moiety having the following structure:

In particular, it is preferred that R1 is an aryl group selected from the group consisting of an alkoxy group. A particular example of R1 is an alkoxy group-substituted phenyl group, especially in the ortho and para positions of the phenyl ring. On the other hand, R1 may be a diarylamino group or an arylthienyl group, for example, the structure shown below, but the invention is not limited thereto.

In a specific embodiment, R1' and R1" are the same. In still another embodiment, R1' and R1" are the same and are selected from the group consisting of hydrogen, halogen (especially fluorine and chlorine), alkoxy groups. Groups such as OCH ₃ and optionally halogenated alkyl groups such as CF ₃ and CH ₃ (CF ₂ ) ₃ CF ₃ . In yet another embodiment, R1 is the same or different from R1' and R1" and is selected from the group consisting of hydrogen, halogen (especially fluorine and chlorine), and substituents including a thiophene moiety having the structure :

In another embodiment, R1, R1', R1", and R1"' are different or identical and are selected from the group consisting of hydrogen and halogens (particularly fluorine and chlorine). In yet another embodiment, R1 and R1"' are different or identical and are selected from the group consisting of hydrogen and halogens (particularly fluorine and chlorine).

In the present invention, R3 may be selected from the group consisting of hydrogen, halogens, cyano groups, and alkyl groups, alkoxy groups, aryl groups, aryloxy groups. Classes, heterocyclics, amine groups and halogenated derivatives thereof, NO ₂ , and anchor groups as defined above. Preferably, R3 is selected from the group consisting of hydrogen, chlorine, fluorine, NO ₂ , -COOH, -PO ₃ H ₂ , -PO ₄ H ₂ , -SO ₃ H, -CONHOH, acetamidine Acetone, acrylic acid derivatives, malonic acid derivatives, rosenin-3-acetic acid, propionic acid, and deprotonated forms or salts thereof; more preferably selected from -COOH or deprotonated-COOH Salts, and substituents including a thiophene moiety having the following structure:

Particularly preferred salts of -COOH are, for example, ammonium salts and alkali metal salts, more preferably -COOTBA. For example, the acrylic acid derivative may be selected from the group having the formula -CH=C(R ^a )-COOH, wherein R ^{a is} selected from the group consisting of hydrogen, cyano, and an alkyl group substituted by at least one halogen atom. Preferred are selected from the group consisting of hydrogen, cyano, and CF ₃ . For example, a malonic acid derivative suitable as an anchor group may be selected from the group having the formula -CR ^b =C(COOH) ₂ wherein R ^{b is} selected from hydrogen and optionally halogenated alkyl groups In particular, it is selected from the group consisting of hydrogen and optionally fluorinated alkyl groups. An alkyne group can be suitably used to extend the anchor group. For example, the anchor group can have the formula -C≡C-COOH.

In the present invention, it is preferred that R2, R2', R2", and R2"' in the chemical formula (II) vary depending on the atom selected for X. In the case of X system C in formula (II), R2, R2', R2", and R2"' are typically independently selected from the group consisting of hydrogen, halogens (especially fluorine and chlorine), a cyano group, as well as an alkyl group, an alkoxy group, an aryl group, an aryloxy group, a heterocyclic ring, an amine group, and a halogenated derivative thereof, NO ₂ , and an anchor group. Preferably, R2, R2 ', R2 " , and R2"' are independently selected from the group consisting of: hydrogen, halogen (e.g. chlorine, fluorine), an alkoxy group such as OCH _3, aryloxy A group such as OPh, a halogenated alkyl group such as C ₆ F ₅ , CF ₃ , and CH ₃ (CF ₂ ) ₃ CF ₃ , and a substituent including a thiophene moiety having the following structure:

In a specific embodiment, R2' and R2" are the same. In still another embodiment, R2' and R2" are the same and are selected from the group consisting of hydrogen, halogens (especially fluorine and chlorine), and alkane. An oxy group such as OCH ₃ , and an optionally halogenated alkyl group such as CF ₃ and CH ₃ (CF ₂ ) ₃ CF ₃ . In still another embodiment, R2 is the same or different from R2' and R2" and is selected from the group consisting of hydrogen, halogens (particularly fluorine and chlorine), and substitutions including a thiophene moiety having the structure base:

In another embodiment, R2, R2', R2", and R2"' are different or identical and are selected from the group consisting of hydrogen and halogens (particularly fluorine and chlorine). In yet another embodiment, R2 and R2"' are different or identical and are selected from the group consisting of hydrogen and halogens (especially fluorine) And chlorine).

In the case of X-form N in formula (II), R 2 , R 2 ', R 2 ′′, and R 2 ′′′ are independently selected from the group consisting of hydrogen, halogen, NO ₂ , and as defined above. Anchoring group. Preferably, R2', R2", and R2"' are hydrogen, and R2 is selected from the group consisting of hydrogen, chlorine, fluorine, NO ₂ , -COOH, -PO ₃ H ₂ , - PO ₄ H ₂ , -SO ₃ H, -CONHOH, acetamidine acetonide, acrylic acid derivative, malonic acid derivative, rosenin-3-acetic acid, propionic acid, and deprotonated form or a salt thereof; Preferred are salts selected from -COOH or deprotonated -COOH, particularly preferred are ammonium salts and alkali metal salts, and more preferably -COOTBA. For example, the acrylic acid derivative may be selected from the group having the formula -CH=C(R ^a )-COOH, wherein R ^a is selected from the group consisting of hydrogen, cyano, and an alkyl group substituted with at least one halogen atom, Preferred is selected from the group consisting of hydrogen, cyano, and CF ₃ . For example, a malonic acid derivative suitable as an anchoring group may be selected from a group having the formula -CR ^b =C(COOH) ₂ wherein R ^b is selected from hydrogen and an optionally halogenated alkyl group. Classes, especially those selected from the group consisting of hydrogen and optionally fluorinated alkyl groups. Alkyn groups may be suitable for use in expanding the anchoring groups. For example, the anchor group can have the formula -C≡C-COOH. In this embodiment, R1 is preferably a phenyl group which may be substituted with an alkoxy group, especially in the ortho and para positions of the phenyl ring.

In a first preferred aspect of the invention, both L1 and L2 are represented by the formula (II), wherein X is N, resulting in two (C^N^N) type tridentate ligands, each having The tridentate ligand and a carbon between M - A metal bond, M is a central atom in the chemical formula (I).

In this first preferred aspect, the two carbons in the benzene rings of the tridentate ligands L1 and L2 are arranged in a cis configuration. Indeed, in this case, the dye has a higher symmetry due to an electron donating carbon anion group ("push") in the benzene ring and an anchor group in the pyridine ring having an anchor group ( "pull") and leads to better electron transfer, "pull" and "push" trans, which led to a better photonic semiconductor (e.g., TiO ₂₎ of the conduction band - to - electron injection.

One of the features of the first preferred aspect of the present invention is that the dye compounds of the formula (I) have two carbon-metal bonds, wherein the carbon atoms are present on the terminal side of each tridentate ligand. This feature is advantageous over the use of two or four anchoring groups for adsorption to the TiO ₂ surface. Additionally, the position of the coordination of the two carbon atoms results in a cis configuration that is inverted with the terminal anchoring group, which provides directionality in the excited state of the photosensitizer.

In this first preferred aspect, the ligands L1 and L2 may be the same or different, preferably the same. In this case, it is especially advantageous when only one ligand (rather than two or three ligands) is required to prepare the dye compounds, and the resulting molecules are symmetrical. This preferred aspect allows for better electron transfer and better synthesis yields.

As specific examples of the dye compounds of the first preferred aspect of the present invention, the dye compounds may be represented by the chemical formulae (I-1), (I-2), (I-3), (I-4), (I-5), (I-6), (I-7), (I-8), (I-9), (I-10), (I-11), (I-12), (I -13), (I-14), (I-15), or (I-16) means:

Wherein "Hx" is understood to mean n-hexyl.

In a second preferred aspect of the invention, one of L1 and L2 is represented by the above formula (II), wherein X system C produces two carbons between the tridentate ligand and M - a metal bond, M is a central atom of the formula (I).

In the second aspect, the other ligand of L1 and L2, that is, the ligand other than the one represented by the formula (II) (wherein X is C), is preferably the following chemical formula (IV) means:

In the formula (IV), R4, R5, and R6 are selected from the group consisting of hydrogen, halogen, cyano, and an alkyl group, an alkoxy group, an aryl group, an aryloxy group. a group, a heterocyclic ring, an amine group and a halogenated derivative thereof, NO ₂ , and an anchor group as defined above. Preferably, the groups R4, R5, and R6 selected from the group consisting of: hydrogen, chlorine, _{fluorine, NO 2, -COOH, -PO 3} H 2, -PO 4 H 2, -SO 3 H , -CONHOH, acetoacetate, acrylic acid derivatives, malonic acid derivatives, rosenin-3-acetic acid, propionic acid, and deprotonated forms or salts thereof; more preferably selected from -COOH or Deprotonated salts of -COOH, and substituents including a thiophene moiety having the following structure:

Particularly preferred salts of -COOH are, for example, ammonium salts and alkali metal salts, more preferably -COOTBA. For example, the acrylic acid derivative may be selected from the group having the formula -CH=C(R ^a )-COOH, wherein R ^{a is} selected from the group consisting of hydrogen, cyano, and an alkyl group substituted by at least one halogen atom. Preferred are selected from the group consisting of hydrogen, cyano, and CF ₃ . For example, a malonic acid derivative suitable as an anchor group may be selected from the group having the formula -CR ^b =C(COOH) ₂ wherein R ^{b is} selected from hydrogen and optionally halogenated alkyl groups In particular, it is selected from the group consisting of hydrogen and optionally fluorinated alkyl groups. An alkyne group can be suitably used to extend the anchor group. For example, the anchor group can have the formula -C≡C-COOH.

As a specific example of the dye compounds of the second preferred aspect, the dye compounds may be represented by the formula (I-17):

In a third preferred aspect of the invention, at least one of L1 and L2, preferably both, is independently represented by the chemical formula (V) as defined below, which is produced at the tridentate ligand and M Between the two carbon-metal bonds, the M system is the central atom of formula (I).

Wherein R1', R1", R1"', R2, R2', R2", R2"', and R3 have the same meanings as defined above.

As a specific example of the dye compounds of the third preferred aspect, the dye compounds can be represented by the chemical formulas (I-18) and (I-19):

The dye compounds of the present invention may be electrically neutral or neutralized with other counterions to produce a salt form. Examples of such salts include ammonium salts and alkali metal salts of the dye compounds of the present invention. Accordingly, the invention also relates to a salt of a dye compound according to the invention.

The compounds of the invention described herein may be a dye suitable for use in a photoelectric conversion device, particularly a dye sensitized solar cell (DSSC). Accordingly, the present invention also relates to a compound of the present invention or a salt thereof Use in photoelectric conversion devices, especially DSSCs.

The DSSC offers promise for an inexpensive and versatile technology for mass production of solar cells. The dye-sensitized solar cell (DSSC) is formed from a combination of organic and inorganic components that can be produced at low cost. These dye-sensitized solar cells have advantages over silicon-based solar cells in terms of simplified process steps, low manufacturing costs, and transparency. These dye-sensitized solar cells can be fabricated from a flexible substrate to function as a battery having mobility and portability. These dye-sensitized solar cells also have the advantage of being lightweight.

One of the goals that dye-sensitized solar cells are facing is to increase relatively low energy (photovoltaic) conversion efficiencies compared to ruthenium-based solar cells. In order to increase energy conversion efficiency, it would make sense to extend the absorption spectrum wavelength to the infrared region.

One of the basic elements of a DSSC is typically a TiO ₂ (titanium dioxide) sensitized with dye molecules to form the core of the DSSC. TiO ₂ is a preferred material for such particles due to its high resistance to continuous electron transfer. However, TiO ₂ only absorbs a small fraction of those solar photons (those in ultraviolet light). These dye compounds attached to the surface of the semiconductor are used to collect most of the sunlight.

The dye compounds typically consist of a metal atom and an organic structure that provides the desired properties (e.g., broad absorption range, fast electron injection, and stability). The dye is sensitive to visible light. This light is generated in the dye and excites high energy electrons that are rapidly injected into the semiconductor particles (typically TiO ₂ ). The semiconductor of the microparticle acts as a transporter for transporting light-inducing electrons to the outer contact, which is a transparent conductor at the bottom of the semiconductor (typically TiO ₂ ) film.

The construction of a DSSC should be well known to those skilled in the art. Typically, the DSSC includes an anode, a cathode, and an electrolyte arranged in a sandwich configuration for the anode and cathode, and the electrolyte is inserted to separate the two electrodes.

The material for the anode is not limited as long as the anode is formed of a material having conductivity. For a non-limiting example, a substrate comprising electrically conductive transparent glass comprising a small amount of platinum or conductive carbon attached to its surface may be suitably employed. As the conductive transparent glass, a glass made of tin oxide or indium tin oxide (ITO) can be used.

The cathode has a substrate made of electrically conductive transparent glass and a semiconducting layer comprising a semiconductor and a dye compound according to the invention adsorbed thereon. As an example of the conductive transparent glass for the cathode, a glass including the materials described above may be used, but is not limited thereto.

Non-limiting examples of materials for the semiconductor include metal oxides such as titanium oxides, cerium oxides, zinc oxides, tin oxides, tungsten oxides, and indium oxides, preferably TiO _{2 .} And SnO ₂ . TiOF ₂ (titanium oxyfluoride titanium oxide oxyfluoride or titanium fluoride oxide) can also be considered as a suitable semiconductor. TiOF ₂ may be particularly suitable when combined with the fluorinated dyes of the present invention. The materials can be used as the sole semiconductor in the DSSC semiconductor layer or can be combined with any other suitable semiconductor layer material.

The dye compound of the present invention is adsorbed onto the semiconductor. The dye is adsorbed by contacting the cathode comprising a conductive transparent glass substrate and a semiconductor layer formed on the surface with a dye solution comprising the dye compound of the present invention and a solvent. The association of the dye compound with the semiconductor can be maintained by chemical bonding or electrostatic interaction between the anchoring group of the dye complex and the semiconductor material. Other methods for achieving the association of the dye with the semiconductor in addition to the adsorption should be known to those skilled in the art. Accordingly, the present invention also relates to a semiconductor element comprising a semiconductor and a dye compound of the invention or a salt thereof, and more particularly to a semiconductor layer comprising TiO ₂ and a dye compound of the invention or a salt thereof, or TiOF ₂ And the dye compound of the present invention or a salt thereof.

As the electrolyte, a liquid electrolyte, a solid electrolyte, or a solution containing the electrolyte can be used. Preferably, the electrolyte is a redox electrolyte comprising a substance forming a redox system, such as a solution of an imidazolium salt comprising iodine and iodide, the solution forming an I ₃ ^- + 2 e ^- 3 I ^- + I ₂ redox system. As a suitable solvent for the solution, an electrochemically inert substance such as acetonitrile or propionitrile can be used.

For example, the DSSC can be formed by filling the electrolyte in a container and placing the anode and cathode face to face in the electrolyte. The anode and the cathode can be arranged at a desired pitch by sandwiching a spacer between them. Still, familiar with the technology Other methods of making the DSSC should be well understood.

The present invention further relates to a photoelectric conversion device, preferably to a dye-sensitized solar cell comprising the dye compound of the present invention, or to the semiconductor device, and more particularly to a semiconductor comprising the dye compound of the present invention or a salt thereof Semiconductor layer. The dye compounds of the invention are used as a dye, in particular a sensitizing dye, in such devices or batteries.

While the preferred embodiment of the invention has been shown and described, The embodiments described herein are merely exemplary and not limiting. Many variations and modifications of the systems and methods are possible and are within the scope of the invention. Therefore, the scope of the invention is not limited to the embodiments described herein, but is only limited by the scope of the following claims, and the scope of the claims should include all equivalents of the subject matter of the claims.

In the event that any disclosure of patents, patent applications, and publications incorporated herein by reference is inconsistent with the description of the present application, the description may be preferred.

Instance Example 1: Synthesis of Dye 1 (Chemical Formula (I-1)) The synthesis scheme of dye 1 is summarized in Figure 2.

4-(methoxycarbonyl)-2-(4-(methoxycarbonyl)pyridin-2-yl)pyridine-1-oxide

3-Chloroperoxybenzoic acid (mCPBA, 1.33 g, 7.71 mmol) was slowly added to the corresponding 2,2'-bipyridyl-4,4'-dicarboxylic acid dimethyl ester (2 g) at 0 °C. , 7.35 mmol) in CHCl ₃ (100 mL). The resulting solution was stirred at this temperature for 1 hour, then the reaction mixture was allowed to warm to room temperature and stirred overnight. After the reaction was completed, the solvent was evaporated under reduced pressure. By silica gel column chromatography the product was purified as a colorless powder (MeOH: DCM = 1: 19 when R _f = 0.5, a yield of 1.65 g (77.9%)).

¹ H NMR (400 MHz, CDCl ₃ ): 9.34 (s, 1H), 8.91 (d, J = 4.8 Hz, 1H), 8.79 (d, J = 2.8 Hz, 1H), 8.35 (d, J = 6.8 Hz) , 1H), 7.95 (dd, J = 4.8, 1.6 Hz, 1H), 7.89 (dd, J = 6.8, 2.4 Hz, 1H), 3.98 (s, 3H), 3.97 (s, 3H). MS (GC-EI): m / z: C ₁₂ H ₇ BrO to be calculated as 245.97; measured to be 246.

Dimethyl 6-chloro-2,2'-bipyridyl-4,4'-dicarboxylate

Phosphorus oxychloride (4 ml, 42.36 mmol) was slowly added to 4-(methoxycarbonyl)-2-(4-(methoxycarbonyl)pyridin-2-yl)pyridine-1-oxide at 0 °C ( 1 g, 3.47 mmol). The mixture was heated to 110 ° C and stirred overnight. After cooling, water (50 ml) was added to this mixture, then the organic compound was extracted three times with dichloromethane (50 ml), and then the organic phase was washed with brine (50 ml). The organic extract was dried with MgSO _4, and a solvent was removed in a rotary evaporator. By silica gel column chromatography the product was purified as a colorless powder (MeOH: DCM = 1: R f = 0.55, yield 0.63 g (56.2% 39)).

¹ H NMR (400 MHz, CDCl ₃ ): 8.92 (dd, J = 1.6, 0.8 Hz, 1H), 8.89 (d, J = 1.2 Hz, 1H), 8.85 (dd, J = 4.8, 0.8 Hz, 1H) , 7.93 (d, J = 1.6 Hz, 1H), 7.92 (dd, J = 4.8, 1.6 Hz, 1H), 4.01 (s, 3H), 4.00 (s, 3H). MS (GC-EI): m/z : calc. 245.97;

Dimethyl 6-(2,4-difluorophenyl)-2,2'-bipyridyl-4,4'-dicarboxylate

Degassed THF (50 ml) and water (30 ml) were added to 2,4-difluorophenylboronic acid (0.57 g, 3.61 mmol), 6-chloro-2,2'-bipyridyl-4,4 '- dicarboxylate (1 g, 3.26 mmol), potassium carbonate (0.54 g, 3.91 mmol), and a mixture of _{Pd (PPh 3) 4 (0.19} g, 0.16 mmol) in. The solution was refluxed overnight. After cooling, the solvent was evaporated in vacuo. Methanol (50 ml) and sulfuric acid (0.5 ml) were added to the crude mixture. The solution was again refluxed overnight. After completion of the reaction water (50 ml) was added to this mixture and neutralized with NaHCO _3, then (50 ml) and extracted organic with methylene chloride 3 times and then with brine (50 ml) the organic phase was washed. By silica gel column chromatography the product was purified as a white solid (DCM: Hx = 1: 1 when R _f = 0.2, a yield of 0.41 g (32.7%)).

¹ H NMR (400 MHz, CDCl ₃ ): 9.03 (dd, J = 1.6, 0.8 Hz, 1H), 8.95 (d, J = 1.2 Hz, 1H), 8.89 (dd, J = 4.8, 0.8 Hz, 1H) , 8.39 (t, J = 1.6 Hz, 1H), 8.25 (td, J = 8.8, 6.4 Hz, 1H), 7.92 (dd, J = 4.8, 1.6 Hz, 1H), 7.09 (m, 1H), 6.98 ( m, 1H), 4.02 (s, 3H), 4.01 (s, 3H). MS (GC-EI): m/z: 384.09; 384.

6-(2,4-difluorophenyl)-2,2'-bipyridyl-4,4'-dicarboxylic acid

Adding hydrogen to a solution of dimethyl 6-(2,4-difluorophenyl)-2,2'-bipyridyl-4,4'-dicarboxylate (0.3 g, 0.78 mmol) in methanol (50 ml) Potassium oxide (0.15 g, 2.67 mmol). The mixture was refluxed and stirred overnight. The mixture solution was neutralized with a HCl solution. The precipitated product was filtered and washed with methanol and water (yield 0.26 g (93.5%)).

¹ H NMR (400 MHz, DMSO-d ₆ ): 8.92 (d, J = 4.4 Hz, 1H), 8.84 (s, 1H), 8.79 (s, 1H), 8.22 (s, 1H), 8.17 (q, J = 8.0 Hz, 1H), 7.92 (d, J = 4.4 Hz, 1H), 7.46 (t, J = 10.4 Hz, 1H), 7.34 (t, J = 8.0 Hz, 1H), 3.38 (bs, 2H) . MS (GC-EI): m/z : 356.06; 357.

Bis[6-(2,4-difluorophenyl)-2,2'-bipyridyl-4,4'-dicarboxylic acid] ruthenium(II)

6-(2,4-Difluorophenyl)-2,2'-bipyridyl-4,4'-dicarboxylic acid (0.25 g, 0.65 mmol) and [RuCl ₂ (p-isopropylbenzene)] ₂ (0.1 g, 0.164 mmol) was dissolved in DMF (75 mL) and the reaction mixture was warmed to 160 &lt After this, the solvent was removed using a rotary evaporator. Diethyl ether was added to the reaction flask to produce a precipitate which was collected by suction filtration on a sintered glass filter. The precipitate on the filter was dissolved in methanol, and then the solution was concentrated in vacuo. The solution was purified by Sephadex LH-20 column chromatography, and the solid color isolated was obtained as a black powder (yield: 47 mg (35.3%)).

¹ H NMR (400 MHz, DMSO-d ₆ ): 9.02 (s, 2H), 8.73 (s, 1H), 7.57 (d, J = 5.6 Hz, 1H), 7.47 (d, J = 5.6 Hz, 1H) , 6.43 (t, J = 11.2 Hz, 1H), 5.24 (d, J = 8.0 Hz, 1H), 4.09 (bs, 2H). MS (GC-EI): m/z : calc. 812.01; 812.

Example 2: Synthesis of Dye 2 (Chemical Formula (I-3))

Dimethyl 6-(2,3,4-trifluorophenyl)-2,2'-bipyridyl-4,4'-dicarboxylate

Degassed and distilled THF (150 ml) was added to 2,3,4-trifluorophenylboronic acid (0.631 g, 3.59 mmol), 6-chloro-2,2'-bipyridyl-4,4'- dicarboxylic acid dimethyl ester (1 g, 3.26 mmol), , and a mixture of _{Pd (PPh 3) 4 (0.188} g, 0.08 mmol) sodium carbonate (0.38 g, 3.59 mmol) in. The solution was then refluxed overnight. After cooling, the solvent was evaporated under vacuum. The resulting product was purified by silica gel column chromatography, as a white solid (DCM: Hx = 1: 1 when R _f = 0.2). This product was a mixture with the starting material which was recrystallized from DCM. The precipitate was filtered off by filtration (yield: 0.54 g (41.2%)).

¹ H NMR (400 MHz, CDCl ₃ ): 9.06 (m, 1H), 8.98 (d, J = 1.2, 1H), 8.88 (dd, J = 4.8, 0.8 Hz, 1H), 8.37 (t, J = 1.6) , 1H), 7.97 (m, 1H), 7.92 (dd, J = 4.8, 1.6 Hz, 1H), 7.17 (m, 1H), 4.03 (s, 3H), 4.02 (s, 3H). MS (GC-EI): m/z : calc. 402.08;

6-(2,3,4-trifluorophenyl)-2,2'-bipyridyl-4,4'-dicarboxylic acid

To 6-(2,3,4-trifluorophenyl)-2,2'-bipyridyl-4,4'-dicarboxylic acid dimethyl ester (0.5 g, 1.03 mmol) in water (20 ml) and methanol Potassium hydroxide (0.23 g, 4.13 mmol) was added to the solution (50 ml). The mixture was refluxed and stirred overnight. The solution was then neutralized with a HCl solution. The precipitated product was filtered and washed with methanol and water (yield: 0.425 g (90.2%)).

¹ H NMR (400 MHz, DMSO-d ₆ ): 8.92 (d, J = 5.2 Hz, 1H), 8.87 (t, J = 1.2 Hz, 1H), 8.26 (t,, J = 1.6 Hz 1H), 7.97 (m, 1H), 7.93 (dd, J = 4.8, 1.6 Hz, 1H), 7.57 (m, 1H). MS (GC-EI): m/z : calc. 374.05;

Bis[6-(2,3,4-trifluorophenyl)-2,2'-bipyridyl-4,4'-dicarboxylic acid] ruthenium(II)

6-(2,3,4-Trifluorophenyl)-2,2'-bipyridyl-4,4'-dicarboxylic acid (0.3 g, 0.802 mmol) and [RuCl ₂ (p-isopropylbenzene) ₂ (0.124 g, 0.203 mmol) was dissolved in DMF (75 mL), and the reaction mixture was heated to 160 ° C in Ar for 48 hr. After this, the solvent was removed with an evaporator, and diethyl ether was added to the reaction mixture. The resulting precipitate was collected by suction filtration on a sintered glass filter. The precipitate was dissolved in methanol and the solution was then concentrated in vacuo. This solution was purified by Sephadex LH-20 column chromatography as a black powder (yield: 68 mg (39.5%)).

¹ H NMR (400 MHz, DMSO-d ₆ ): 9.04 (m, 2H), 8.72 (s, 1H), 7.56-7.47 (m, 2H), 5.33 (m, 1H), 7.28 (d, J = 8.0 Hz, 1H). MS (GC-EI): m/z : calc. 847.99;

Example 3: Synthesis of a ligand for dye 3 (chemical formula (I-6))

Dimethyl 6-(2,4-dichlorophenyl)-2,2'-bipyridyl-4,4'-dicarboxylate

Degassed and distilled THF (150 ml) was added to 2,4-dichlorophenylboronic acid (0.631 g, 3.59 mmol), 6-chloro-2,2'-bipyridyl-4,4'-dicarboxyl acid dimethyl ester (1 g, 3.26 mmol), sodium carbonate (0.38 g, 3.59 mmol), and mixtures of _{Pd (PPh 3) 4 (0.188} g, 0.08 mmol) in. The solution was refluxed overnight. After cooling, the solvent was evaporated in vacuo. By silica gel column chromatography the product was purified as a white solid (DCM: Hx = 1: 1 when R _f = 0.2). This product is a mixture with the starting materials. The white solid was recrystallized from DCM and then filtered to give a precipitate (yield: 0.54 g (41.2%)).

¹ H NMR (400 MHz, CDCl ₃ ): 9.06 (m, 1H), 8.98 (d, J = 1.2, 1H), 8.88 (dd, J = 4.8, 0.8 Hz, 1H), 8.37 (t, J = 1.6) , 1H), 7.97 (m, 1H), 7.92 (dd, J = 4.8, 1.6 Hz, 1H), 7.17 (m, 1H), 4.03 (s, 3H), 4.02 (s, 3H).

6-(2,4-dichlorophenyl)-2,2'-bipyridyl-4,4'-dicarboxylic acid

To 6-(2,4-bis(trifluoromethyl)phenyl)-2,2'-bipyridyl-4,4'-dicarboxylic acid dimethyl ester (0.4 g, 0.96 mmol) in water (20 ml Potassium hydroxide (0.23 g, 4.13 mmol) was added to a solution of methanol (50 ml). The mixture was refluxed and stirred overnight, after which the reaction solution was neutralized with a HCl solution. The precipitated product was filtered and washed with methanol and water (yield: 0.31 g (83.0%)).

¹ H NMR (400 MHz, DMSO-d ₆ ): 8.93 (d, J = 4.8 Hz, 1H), 8.87 (s, 1H), 8.82 (s, 1H), 8.14 (s, 1H), 7.93 (dd, J = 5.2, 1.2 Hz, 1H), 7.82 (m, 2H), 7.64 (dd, J = 8.4, 2.0 Hz, 1H).

Figure 1: Synthesis scheme for preparing a ligand of the (C^N^N) type, which Wherein R1, R1', and R1" are independently selected from the group consisting of hydrogen, alkoxy groups, halogens, and optionally halogenated alkyl groups.

Figure 2: Synthetic route of chemical formula (I-1)

Figure 3: Normalized UV absorption spectrum of Formula (I-1) prepared according to Example 1, as measured by a Hewlett-Packard 8453 UV-Vis spectrometer in a 1.0 x 10 ^-4 M ethanol solution.

Figure 4: Normalized UV absorption spectrum of Chemical Formula (I-3) prepared according to Example 2, as measured by a Hewlett-Packard 8453 UV-Vis spectrometer in a 1.0 x 10 ^-4 M ethanol solution.

Figure 5: Synthetic route of formula (I-11).

Claims (16)

A dye compound of formula (I): ML1L2 (I) wherein M represents a metal belonging to Group 6, 8, 9, 10, or 11 of the long-form periodic table; L1 and L2 are independently selected from tridentate In the group, at least one of L1 and L2 conforms to the chemical formula (T): Aa-Ab-Ac (T) wherein Aa, Ab, and Ac are each an aromatic group, and Aa is bonded to the metal via a metal-carbon bond M is attached to M by a metal-nitrogen bond, and Ac is attached to M by a metal-X bond, wherein X is selected from C and N, and the dye compound of formula (I) has two Carbon-metal bonds. The dye compound of claim 1, wherein at least one of L1 and L2 is in accordance with formula (II) or formula (V): Wherein X is selected from C and N, and R1, R1', R1", and R1"' are independently selected from the group consisting of hydrogen, halogen, cyano, and alkyl groups, alkoxy groups An aryl group, an aryloxy group, a heterocyclic ring, an amine group, and a halogenated derivative thereof, and R3 is selected from the group consisting of hydrogen, halogen, cyano, and an alkyl group, An alkoxy group, an aryl group, an aryloxy group, a heterocyclic ring, an amine group, and a halogenated derivative thereof, NO ₂ , and an anchoring group, and if the X system is C, Then R2, R2', R2", and R2"' are independently selected from the group consisting of hydrogen, halogen, cyano, and alkyl groups, alkoxy groups, aryl groups, aromatic An oxy group, a heterocyclic ring, an amine group, and a halogenated derivative thereof, NO ₂ , and an anchor group, or if X is N, then R 2 , R 2 ', R 2 ′′, and R 2 ′′ are independently selected Free group of the following: hydrogen, halogen, NO ₂ , and anchoring groups. A dye compound according to claim 1, wherein M in the formula (I) is selected from the group consisting of iron, ruthenium, osmium, iridium, cobalt, palladium, platinum, and chromium, preferably ruthenium. The dye compound of claim 2, wherein the anchoring group is selected from the group consisting of -COOH, -PO ₃ H ₂ , -PO ₄ H ₂ , -SO ₃ H, -CONHOH, Acetyl acetonide, acrylic acid derivative, malonic acid derivative, rosenin-3-acetic acid, propionic acid, the above-described deprotonated form, the deprotonated form of the salt, and having π-conducting properties The chelating group is preferably a salt of -COOH and -COOH, more preferably -COOH and an ammonium or alkali metal salt of -COOH. A dye compound according to claim 2, wherein R1' and R1" are the same, and preferably hydrogen, fluorine, chlorine, or CF ₃ . The patentable scope of application of the dye compound of item 2, wherein the same R2 'and R2 "system, and is preferably hydrogen, fluoro, chloro, or CF _3. A dye compound according to claim 2, wherein both L1 and L2 are represented by the chemical formula (II), and in the chemical formula (II), X is N. A dye compound as claimed in claim 2, wherein L1 and L2 are the same. A dye compound according to claim 2, wherein X is N and R2 is the anchor group, preferably -COOH or a salt thereof. The dye compound of claim 1, wherein the dye compound is selected from the group consisting of formula (I-1), (I-2), (I-3), (I-4), (I-5), (I) -6), (I-7), (I-8), (I-9), (I-10), (I-11), (I-12), (I-13), (I-14 ), (I-15), (I-16), (I-18), or (I-19) A dye compound according to claim 2, wherein one of L1 and L2 is represented by the formula (II), and in the formula (II), X is C. A dye compound according to claim 11 wherein the ligand other than the one represented by the formula (II) is represented by the formula (IV): Wherein R 4 , R 5 , and R 6 are independently selected from the group consisting of hydrogen, halogen, cyano, and an alkyl group, an alkoxy group, an aryl group, an aryloxy group, a hetero Ring, amine groups and their halogenated derivatives, NO ₂ , and anchor groups. The dye compound of claim 12, wherein the anchoring group is selected from the group consisting of -COOH, -PO ₃ H ₂ , -PO ₄ H ₂ , -SO ₃ H, -CONHOH, Acetyl acetonide, acrylic acid derivative, malonic acid derivative, rosin-3-acetic acid, propionic acid, deprotonated forms of the above, salts of the deprotonated form, and chelates having π-conducting properties The hydrating group is preferably a salt of -COOH and -COOH, more preferably -COOH and an ammonium or alkali metal salt of -COOH. A dye compound according to claim 11 wherein the dye compound is selected from the group consisting of formula (I-17): A semiconductor component, in particular a semiconductor layer, comprising a semiconductor and a dye compound according to any one of claims 1 to 14. A dye-sensitized solar cell comprising the dye compound according to any one of claims 1 to 14 or the semiconductor element according to claim 15 of the patent application.