KR102428202B1 - Electrochemically polymerized multilayer molecular assembly and method for manufacturing same - Google Patents

Abstract

The present invention provides a method for manufacturing a multi-layered molecular assembly by step-by-step and selective polymerization using an electrochemical oxidation and reduction method, and selectively polymerizes layers having different functions by using electrochemically step-by-step oxidation and reduction reactions. can get angry
According to an embodiment of the present invention, it is possible to provide a photovoltaic device having excellent optical and electrical stability by using a multi-layered molecular assembly.

Description

Electrochemically polymerized multilayer molecular assembly and method for manufacturing same

The present invention relates to a multilayer molecular assembly and a method for manufacturing the same, and more particularly, to a multilayer molecular assembly bonded by electrochemical polymerization, a method for manufacturing the same, and a photoelectric synthesis device to which the same is applied.

A photoelectrochemical reaction refers to an electrochemical reaction induced by light energy. Typically, photosynthesis in plants is also a type of photoelectrochemical reaction, and chloroplasts absorb light energy and oxidize water. On the other hand, although hydrogen is a next-generation clean energy source that does not emit pollutants during combustion, the generation method through fossil fuels is the main method. was proposed as

Water decomposition is a reaction mechanism that generates hydrogen gas by solar energy in a photovoltaic device. The photovoltaic device consists of two parts, a photoanode and a counter electrode, wherein the photoanode is an oxygen evolution reaction; hereinafter 'OER', 2H ₂ O+4hν→ O ₂ +4H ⁺ +4e ^- ) occurs, and a hydrogen evolution reaction (hereinafter 'HER', 4H ⁺ +4e ^- → 2 H ₂ ) occurs in the counter electrode.

Based on the principle of natural photosynthesis, artificial photosynthesis research is progressing toward a fundamental understanding of the photophysical and photoelectrochemical properties of semiconductor materials and their practical application in various forms of photosynthetic devices. However, most organic dyes used in photoanodes are not only unstable in water due to radical cationic species after electron injection, but also have problems such as low oxygen generation efficiency, and various studies have been conducted to solve this problem. .

On the other hand, in the case of a molecular-based photovoltaic device, there is a problem in that the stability is low, and the practical useability is low. Accordingly, various chemical and physical methods have been devised and proposed to increase stability, but the conventional method has a problem in that it exhibits high manufacturing cost or low stability.

Accordingly, various methods have been sought to solve the high cost and low stability of molecular-based photovoltaic device fabrication. Among them, electrochemical polymerization is attracting attention and research is being conducted, but in the case of conventional electrochemical polymerization, only a simple form of polymerization has been carried out, and research is still needed on a manufacturing method for selectively polymerizing several functional layers as much as desired. the current situation.

One object of the present invention is to provide a multi-layered molecular assembly having various functions.

Another object of the present invention is to provide a stable photovoltaic device to which the multi-layered molecular assembly is applied.

Another object of the present invention is to provide a method for preparing a multi-layered molecular assembly having various functions by polymerization using an electrochemical method.

The technical tasks to be achieved by the multilayer molecular assembly according to the technical spirit of the present invention are not limited to the tasks mentioned above, and other tasks not mentioned will be clearly understood by those skilled in the art from the following description.

This will be described in detail as follows. Meanwhile, each description and embodiment disclosed in the present application may be applied to each other description and embodiment. That is, all combinations of the various elements disclosed in this application fall within the scope of this application. In addition, it cannot be seen that the scope of the present application is limited by the detailed description described below.

In order to achieve the above object, according to an embodiment of the present invention, a protective layer formed on a metal oxide and composed of an organic material; a color development layer electrochemically polymerized with the protective layer; and a catalyst layer that is in electron transfer communication with the chromophoric layer and is electrochemically polymerized with the chromophoric layer.

According to an embodiment, the metal oxide may include core-shell nanoparticles including a core material that is at least partially surrounded by a shell material.

According to an embodiment, the metal oxide is tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), antimony tin oxide (ATO), gallium zinc oxide (GZO), indium zinc oxide (IZO), It may include at least one selected from the group consisting of copper aluminum oxide (CAO), fluorine-doped zinc oxide (FZO), zinc aluminum oxide (AZO), and combinations thereof.

According to an embodiment, the core material may be SnO ₂ , and the shell material may be TiO ₂ .

In order to achieve the above object, according to an embodiment of the present invention, a counter electrode; electrolyte; and an electrode, wherein the electrode includes a multilayer molecular assembly.

According to an embodiment, the electrochemical device may be a dye-sensitized photoelectrosynthesis cell (DSPEC).

In order to achieve the above object, according to an embodiment of the present invention, the step of fixing a protective layer on the surface of the metal oxide; bonding the protective layer and the color-developing layer through a first electrochemical polymerization; And it provides a method for manufacturing a multi-layer molecular assembly comprising the step of combining the chromophoric layer and the catalyst layer by a second electrochemical polymerization.

According to an exemplary embodiment, the first electrochemical polymerization may be oxidation eletropolymerization, and the second electrochemical polymerization may be reduction eletropolymerization.

According to the present invention, the electrochemically polymerized multilayer molecular assembly exhibits high stability and utility due to electrochemical bonding between molecular layers performing various functions.

In addition, the photoelectric synthesis device using the molecular assembly according to the present invention can exhibit superior optical and electrical stability than the conventional molecular-based photovoltaic device, and can be implemented at various pHs. In addition, in the photovoltaic device, the photoanode can continuously decompose water without reducing the photocurrent, and it is possible to efficiently generate oxygen with high Faraday efficiency.

In addition, the method for manufacturing a molecular assembly according to the present invention can selectively polymerize layers having different functions by using electrochemically step-by-step oxidation and reduction reactions, thereby manufacturing a multi-layered molecular assembly having a uniform molecular layer. can do.

However, effects that can be achieved by the multilayer molecular assembly according to an embodiment of the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the following description. will be able

In order to more fully understand the drawings cited herein, a brief description of each drawing is provided.
1 is a diagram schematically illustrating a multi-layered molecular assembly according to an embodiment of the present invention.
2 is a view schematically showing surface synthesis by electrochemical polymerization according to an embodiment of the present invention.
3 is a diagram illustrating a process of synthesizing a multi-layered molecular assembly according to an embodiment of the present invention.
4 is a diagram schematically illustrating the surface synthesis of a multi-layered molecular assembly according to an embodiment of the present invention.
5 is a view showing a comparison of photostability and loading ratio dependence of a multi-layered molecular assembly according to an embodiment of the present invention.
6 is a view showing a comparison of photocurrent of a device to which a multi-layered molecular assembly is applied according to an embodiment of the present invention, (a) TiO ₂ and SnO ₂ Core/TiO ₂ Comparison of photocurrent of a shell, (b) SnO ₂ core /TiO ₂ Represents a slow BET process in the shell.
7 is a view showing comparison of photocurrent and photostability at various pHs of a device to which a multi-layered molecular assembly is applied and a conventional molecular-based device according to an embodiment of the present invention.
8 is a diagram illustrating a comparison of photostability between a device to which a multi-layered molecular assembly is applied and a conventional molecular-based device according to an embodiment of the present invention.
9 is a view showing a comparison of photocurrent and photostability at various pHs of a device to which a multi-layered molecular assembly is applied and a conventional molecular-based device according to an embodiment of the present invention.
10 is a view showing a photoelectrolysis test result of a device to which a multi-layered molecular assembly according to an embodiment of the present invention is applied.
11 is a diagram illustrating application of a multilayer molecular assembly according to an embodiment of the present invention to a photovoltaic device.
12 is a view showing ¹ H-NMR spectrum of a compound included in a chromophoric layer according to an embodiment of the present invention, (a) ¹ H-NMR spectrum of Ru(bpy) ₂ -thiop compound, (b) Ru ¹ H-NMR spectrum of (vinylbpy) ₂ -thiop compound.

Since the invention disclosed in this specification can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings, and this will be described in detail through the detailed description. However, this is not intended to limit the technology disclosed herein to specific embodiments, and it should be understood that the technology disclosed herein includes all modifications, equivalents and substitutions included in the spirit and scope of the present invention.

In describing the invention disclosed in the present specification, if it is determined that a detailed description of a related known technology may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. In addition, numbers (eg, first, second, etc.) used in the description process of the present specification are only identification symbols for distinguishing one component from other components.

In the present specification, when a member is said to be located “on” another member, this includes not only a case in which a member is in contact with another member but also a case in which another member is present between the two members.

In the present specification, when a part "includes" a certain component, it means that other components may be further included rather than excluding other components unless otherwise stated.

As used herein, the terms "about," "substantially," and the like, to the extent used in this disclosure, are used in a sense at or close to the numerical value when the manufacturing and material tolerances inherent in the stated meaning are presented, and are intended to enhance the understanding of this application. To help, precise or absolute figures are used to prevent unfair use by unscrupulous infringers of the stated disclosure.

The term “step of” or “step of” as used in the present disclosure does not mean “step for”.

In the present specification, the term "combination of these" included in the expression of the Markush format means one or more mixtures or combinations selected from the group consisting of the components described in the expression of the Markush format, and the components It means to include one or more selected from the group consisting of.

In addition, each of the components to be described below may additionally perform some or all of the functions of other components in addition to the main functions they are responsible for, and some of the main functions of each component may be different It goes without saying that it may be performed exclusively by the component.

Expressions such as "first", "second", "first", or "second" used in various embodiments may modify various elements regardless of order and/or importance, do not limit For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be renamed to a first component.

Hereinafter, embodiments of the present invention will be described in detail in turn.

1 is a view showing an electrochemically polymerized multilayer molecular assembly according to an embodiment of the present invention.

According to an embodiment, the multilayer molecular assembly may include a protective layer- a color-developing layer- a catalyst layer.

In the present disclosure, "multi-layer" is interpreted to include a multi-functional layer that performs different functions.

As used herein, the term “chromophore” refers to a compound layer that absorbs light in the visible region. In general, the chromogenic layer absorbs one or more photons of light to reach an excited state, and electron transfer may occur. This means that one or more photons having a wavelength of about 350 nm to about 1000 nm are absorbed by the chromophore to reach one or more excited states.

According to an embodiment, the chromophoric layer includes, but is not limited to, a metal coordination complex having a metal-ligand structure, a porphyrin, a phthalocyanine, an organic dye, and combinations thereof. Illustratively, the metal included in the metal coordination complex is silicon (Si), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), osmium (Os), copper (Cu), iridium ( Ir), iron (Fe), cobalt (Co), nickel (Ni), manganese (Mn), magnesium (Mg), or ruthenium (Ru).

According to one embodiment, the ligand included in the metal coordination complex may be a bi-pyridine compound represented by Formula 1 below:

[Formula 1]

Here, R ₁ and R ₂ are each independently hydrogen (H), halogen, carboxyl group, sulfonic acid group, thiophene group, pyrrole group, amide group, ester group, acetyl group, siloxane group, alkyl group having 1 to 10 carbon atoms, carbon number Contains any one or more of an alkylene group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an oxyalkylene group having 1 to 10 carbon atoms, a fluorinated alkyl group having 1 to 10 carbon atoms, an arylalkyl group having 4 to 20 carbon atoms, or derivatives thereof. .

According to an embodiment, referring to FIG. 3 , the chromophoric layer may include Ru Dye, and may be exemplarily provided by the following synthesis method.

Ru Dye 1

Ru Dye 1 : [Ru(bpy) ₂ (thiop)] ²⁺

(bpy= 2,2’-bipyridine, thiop= 4,4’-di(thiophen-2-yl)-2,2’-bipyridine)

Ru Dye 1 is the paper Inorg. Chem. 2013, 52, 21, was prepared with reference to 12492-12501.

According to one embodiment, Ru(bpy) ₂ Cl ₂ (0.2g, 0.41mmol), 4,4'-di(thiophen-2-yl)-2,2'-bipyridine (0.1g) in a 50mL two-necked round flask , 0.79 mmol) is dissolved in EtOH/H ₂ 0 20 mL. Stir under reflux at 70°C for 24 hours. Store the filtered compounds under reduced pressure with diethyl ether. Separate the compounds cleanly with Sephadex. Apply a vacuum to completely blow off any remaining solvent. Yield: 80%;

NMR data for substance identification: ¹ H NMR (500 MHz, Acetone-d ₆ ): δ 9.07 (s, 2H) 8.70 (d, 4H) 8.07 (t, 6H) 7.93 (d, 2H) 7.92 (d, 2H) ) 7.85 (d, 2H) 7.69 (d, 2H) 7.61 (d, 2H) 7.47 (t, 4H) 7.18 (t, 4H).

Ru Dye 2

Ru Dye 2 : [Ru(dvbpy) ₂ (thiop)] ²⁺

(dvbpy = 4,4’-Divinyl-2,2’-bipyridine)

Ru Dye 2 was published in the paper J. Org. Chem. 2011, 76, 11, was prepared with reference to 4771-4775.

According to one embodiment, Ru(vinylbpy) ₂ Cl ₂ (0.2g, 0.34mmol), 4,4'-di(thio-phen-2-yl)-2,2'-bipyridine ( 0.13 g, 0.41 mmol) is dissolved in 20 mL of EtOH/H ₂ 0. Stir under reflux at 70°C for 24 hours. Store the filtered compounds under reduced pressure with diethyl ether. Separate the compounds cleanly with Sephadex. Apply a vacuum to completely blow off any remaining solvent. Yield: 80%

NMR data for substance identification: ¹ H NMR (500 MHz, Acetone-d ₆ ): δ 9.20 (s, 2H) 8.97 (d, 4H) 8.79 (s, 2H) 8.74 (d, 2H) 8.15 (d, 2H) ) 8.03 (m, 8H) 7.88 (d, 2H) 7.84 (d, 2H) 7.76 (m, 4H) 7.72 (d, 2H) 7.62 (q, 4H) 7.32 (t, 2H) 7.28 (t, 2H)6.93 (m, 6H) 6.36 (dd, 6H) 5.74 (m, 6H).

According to one embodiment, Ru Dye 1 may be used as a comparative material of Ru Dye 2 to find out the conditions that can be maximally accumulated in the chromogenic layer, and Ru Dye 2 having a vinyl group is subjected to a catalyst layer and electroreduction polymerization process to obtain several It can be used as a material to form molecular assemblies of layers. An electroreduction polymerization reaction is carried out between substances having a vinyl group. In an embodiment of the present invention, either one of Ru Dye 1 and 2 may be selectively introduced into the chromophore layer.

According to an embodiment, the color development layer may be assembled with the catalyst layer by electrochemical polymerization. The chromophoric layer and the electrochemically polymerized catalyst layer are in electron-transfer communication with the chromophore, and can absorb one or more photons and participate in electron transfer. This can occur when the chromophore absorbs photons of light and transfers electrons to the catalyst layer. In this case, one or more electrons may be involved. Exemplarily, the chromophoric layer may oxidize the catalyst after absorption of the first photon, and then further oxidize the catalyst by absorption of the second photon.

According to an embodiment, the chromophoric layer includes a vinyl-functionalized complex and may be combined with the catalyst layer by electrochemical polymerization. For example, referring to FIG. 4 , a vinyl group included in the color development layer may be combined with a vinyl group included in the catalyst layer through reduction eletropolymerization.

According to an embodiment, in the electrooxidative polymerization, pyrrole and thiophene-type molecules may form a carbon-carbon bond under a positive voltage condition.

According to an embodiment, in the electroreduction polymerization, molecules having a vinyl group may form a carbon-carbon bond under negative voltage conditions. In particular, the electroreduction polymerization of compounds having a vinyl functional group has electrochemical and photochemical stability even at high pH.

The electrochemical polymerization method according to the present invention can be synthesized in a short period of time compared to a method of synthesizing an assembly (dye-catalyst assembly) at once, and the technique for synthesizing single molecules required for assembly is not difficult, so synthesis in a relatively easy environment This is possible. In particular, since the single molecules are sequentially assembled, the role of each can be identified and controlled.

According to an embodiment, as the catalyst material included in the catalyst layer, any material that promotes a chemical reaction of another molecule may be used without limitation. Illustratively, the catalyst material is [Ru(tpy)(bpy)(OH ₂ )] ²⁺ , [Ru(tpy)(bpm)(OH ₂ )] ²⁺ , [Ru(tpy)(bpz)(OH) ₂ )] ²⁺ , [Ru(tpy)(Mebim-pz)(OH ₂ )] ²⁺ , [Ru(tpy)(Mebim-py)(OH ₂ )] ²⁺ , [Ru(DMAP)(bpy) (OH ₂ )] ²⁺ , [Ru(Mebimpy)(bpy)(OH ₂ )] ²⁺ , [Ru(Mebimpy)(Mebim- pz)(OH ₂ )] ²⁺ , [Ru(Mebimpy)(Mebimpy) (OH ₂ )] ²⁺ , {Ru(Mebimpy)[4,4′- ((HO) ₂ OPCH ₂ ) ₂ bpy](OH ₂ )} ²⁺ , Os(tpy)(bpy)(OH ₂ ) ^{2 +} and combinations thereof. where bpm is 2,2'-bipyrimidine; bpz is 2,2'-bipyrazine; Mebim-pz is 3-methyl-1 -pyrazylbenzimidazol-2-ylidene; Mebim-py is 3-methyl-1-pyridylbenzimidazol-2-ylidene; Mebimpy is 2,6-bis(1-methylbenzimidazol-2-yl)pyridine; And DMAP is 2,6-bis((dimethylamino)methyl)pyridine.

According to one embodiment, the catalyst material may be a compound represented by the following formula (2), a salt thereof, or a derivative thereof:

[Formula 2]

Ru(2,2′-bipyridine-6,6′-dicarboxylate)(R ₃ )(R ₄ )

Here, R ₃ and R ₄ independently of each other include any one or more of pyridine, 4-vinyl pyridine, pyridin-4-yl methyl phosphonic acid and deprotonated derivatives thereof, and substituted/unsubstituted isoquinoline. Illustratively, the catalyst material may be Ru((2,2′-bipyridine-6,6′-dicarboxylate)(4-vinylpyridine) ₂ , a salt or a derivative thereof. In another exemplary embodiment, the catalyst material may be Ru((2,2′-bipyridine-6,6′-dicarboxylate)(pyridin-4-ylmethylphosphonic acid) ₂ , a salt or a derivative thereof. In another example, the catalyst material is IrO ₂ nano It may be a particle.

According to one embodiment, the catalyst layer may be adapted to carry out at least one chemical reaction. Here, an appropriate chemical reaction may occur. Illustratively, water may be oxidized. As another example, carbon dioxide may be reduced. As another example, an electron scavenger or a hole scavenger may be reduced or oxidized, respectively. Illustratively, the scavengers include, but are not limited to, hydroquinone and iodide/tri-iodide.

The molecular assembly according to an embodiment of the present invention may be manufactured by stepwise assembly of several layers having various functions. 2 and 3 show a process of synthesizing a multi-layered molecular assembly according to an embodiment of the present invention.

Referring to FIG. 2 , a protective layer is loaded on an arbitrary metal oxide, and then, the protective layer and the chromophoric layer are combined by Oxidation Eletropolymerization, and the chromophoric layer and the catalyst layer are electrically It can be polymerized by reduction polymerization to form a multilayer molecular assembly.

According to one embodiment, the protective layer may be composed of an organic material capable of electrooxidative polymerization. In general, an organic material capable of electrooxidative polymerization has aromaticity, and must be oxidized at a relatively low potential in which a solvent or electrolyte salt is not decomposed. In addition, an electrophilic substitution reaction may occur while the directionality is maintained. Illustratively, the organic material is pyrrole, bipyrrole, terpyrrol, thiophene, bithiophene, terthiophene, azulene, Pyrene (Pyrene), carbazole (Carbazole), and derivatives thereof include, but are not limited thereto.

Referring to FIG. 3 , the passivation layer may include terthiophene dye which is an organic layer (OrgD), and may be provided by way of example as follows.

organic layer (OrgD)

Step 1: Diethyl[2,2’:5’,2’’-terthiophene]-5-ylphosphonate)

According to one embodiment, 2,2':5',2''-terthiophene (0.3g, 0.91mmol) is dissolved in 25mL of THF in a 100mL two-necked round flask. After confirming that the solution is uniformly dissolved, the solution is purged with argon for about 10 minutes. For the n-BuLi reaction, the temperature of the flask is maintained at -78°C using dry ice. After 10 minutes, n-BuLi (0.23 mL, 1.83 mmol) is slowly added dropwise to the flask. After 10 minutes, diethylchlorophosphate (0.77 mL, 5.50 mmol) is slowly added dropwise. Remove the dry ice bath and stir at room temperature for 12 hours. To finish the reaction and remove the remaining substances, the reaction is completed with an excess of distilled water and diethyl ether solvent. The compound in the diethyl ether layer is extracted, and distilled water remaining in the organic solvent is removed by adding MgSO ₄ . It pressure-reduced _in order to filter MgSO4. Then, the remaining solvent is removed using a rotary evaporator. Column chromatography method was used to obtain the compound. Yield: 50%

NMR data for substance identification: ¹ H NMR (500 MHz, CDCl ₃ ): δ 7.84 (d, 1H) 7.58 (d, 1H) 7.52 (d, 1H) 7.48 (d, 1H) 7.46 (d, 1H) 7.25 (d, 1H) 7.06 (t, 1H) 4.14 (m, 4H) 1.21 (t, 6H).

Step 2: ([2,2':5',2''-terthiophene]-5-ylphosphonic acid)

According to one embodiment, Diethyl[2,2':5',2''-terthiophene]-5-ylphos-phonate (0.6g, 1.56mmol), Bromotrimethylsilane (2.02mL, 15.6mmol) in a 100mL two-necked round flask is dissolved in 10 mL of CH ₂ Cl ₂ . Argon purging was carried out for about 20 minutes, followed by stirring at room temperature for 5 hours. To finish the reaction and remove the remaining substances, the reaction is completed with an excess of distilled water and a CH ₂ Cl ₂ solvent. Extracting the compound in the CH ₂ Cl ₂ layer, and adding MgSO ₄ to remove the distilled water remaining in the organic solvent. It pressure-reduced _in order to filter MgSO4. Then, the remaining solvent is removed using a rotary evaporator. [2,2':5',2''-terthiophene]-5-ylphosphonic acid as a dark yellow-green solid was obtained by column chromatography. Yield: 70%

NMR data for substance identification: ¹ H NMR (500 MHz, D ₂ O): δ 7.86 (d, 1H) 7.50 (s, 2H) 7.43-7.38 (m, 2H) 7.20 (d, 1H) 7.06 (t, 1H) 1.91 (s, 1H).

According to one embodiment, the protective layer may be secured to the metal oxide surface in any suitable manner. A method of loading the protective layer may include a covalent bond, an ionic bond, and a combination thereof.

According to one embodiment, the molecular assembly may be formed on any suitable metal oxide surface, including conductive, semiconducting and insulating metal oxide surfaces. For example, it may be formed on the surface of the core-shell nanoparticles. Illustratively, the metal oxide is tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), antimony tin oxide (ATO), gallium zinc oxide (GZO), indium zinc oxide (IZO), copper aluminum oxide ( CAO), fluorine-doped zinc oxide (FZO), zinc aluminum oxide (AZO), and combinations thereof. In another exemplary embodiment, the metal oxide is SiO ₂ , Sn0 ₂ , Ti0 ₂ , Al ₂ O ₃ , Nb ₂ 0 ₅ , SrTi0 ₃ , Zn ₂ Sn0 ₄ , Zr0 ₂ , NiO, V ₂ O ₅ , MoO ₃ , WO ₃ , Ta ₂ O ₅ , Nb ₂ O ₂ , Ta-doped TiO ₂ , Nb-doped TiO ₂ , and combinations thereof.

According to one embodiment, the metal oxide surface may be of any suitable shape. Illustratively, monolithic, single crystal, nanocrystalline, porous or nonporous, micron-size particles and an average size of about 1 It may be in the form of nanoparticles that are smaller than μm.

The molecular assembly according to an embodiment of the present invention may be applied to an electrochemical device such as a dye-sensitized photoelectrochemical device (PEC).

According to an embodiment, the electrochemical device may be a dye-sensitized photoelectrosynthesis cell (DSPEC) including a counter electrode, an electrolyte, and an electrode. Here, an appropriate counter electrode may be used. Illustratively, it may be selected from platinum, nickel, ceramic, and combinations thereof, but is not limited thereto. Also, a second electrode or a third electrode configuration may be used, the third electrode being any suitable reference electrode. Illustratively, the reference electrode may be selected from a standard hydrogen electrode (SHE), a normal hydrogen electrode (NHE), a silver chloride electrode, a saturated calomel electrode (SCE), and a saturated sodium calomel electrode (SSCE).

Also, any suitable electrolyte may be used. Illustratively, the electrolyte is an I ^- /I ₃ ^- oxidation-reduction electrolyte, an electrolyte including dissolved LiI/I ₂ , and a plurality of conventional organic solvents including THF, DMSO, DMF, various nitriles, alcohols, and the like. , an aqueous electrolyte, water, an alkaline electrolyte, an acidic electrolyte, and the like, but is not limited thereto.

In the electrochemical device according to an embodiment of the present invention, any useful photoelectrochemistry may be performed.

According to an embodiment, it may include a process of decomposing water (H ₂ O) into hydrogen (H ₂ ) and oxygen (O ₂ ) to convert it into hydrogen energy. For example, when a photon (solar energy) having energy greater than or equal to the band gap energy is incident on a photoelectrode made of a semiconductor material, electron hole pairs (EHP) are formed in the semiconductor by the photoelectric effect, Electron hole pairs (EHP) are separated by band bending at the semiconductor-electrolyte interface. The separated holes (h ⁺ ) oxidize water (H ₂ O) at the semiconductor-electrolyte interface to generate proton ions (H ⁺ ) and generate oxygen gas (O ₂ ). The separated electrons (e ⁻ ) move to the cathode along the external circuit, and the proton ions (H ⁺ ) moved through the electrolyte are reduced at the cathode-electrolyte interface to generate hydrogen gas (H ₂ ).

According to an embodiment, the photoanode electrode may include a multilayer molecular assembly having core-shell nanoparticles in contact with the conductive substrate and a protective layer in contact with the nanoparticles. In the photoanode electrode, the reaction in the electrolyte is 2H ₂ O → O ₂ + 4H ⁺ + 4e ^- .

According to one embodiment, any suitable conductive substrate may be used for the electrode. The material constituting the conductive substrate is a concept including all conductive materials such as transparent conductive oxide (TCO), transparent conductive polymer, carbon conductive material, metal, metal oxide, metal nitride, and metal oxynitride. Illustratively, the conductive metal oxide is tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), antimony tin oxide (ATO), gallium zinc oxide (GZO), indium zinc oxide (IZO), copper aluminum oxide (CAO), fluorine-doped zinc oxide (FZO), zinc aluminum oxide (AZO), and combinations thereof. Conductive metal oxides are transparent and transmit more than 50% of the visible light spectrum. The electrodes may have suitable dimensions and geometric shapes, and may have a planar shape.

According to an embodiment, the electrode may include one or more core-shell nanoparticles including a core material surrounded at least partially by a shell material. The core-shell nanoparticles may include the same material or may be a mixture of core-shell nanoparticles having different materials. Any suitable core material may be used, and in some cases the core material may be a semiconductor metal oxide. Illustratively, the core material is tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), antimony tin oxide (ATO), gallium zinc oxide (GZO), indium zinc oxide (IZO), copper aluminum oxide ( CAO), fluorine-doped zinc oxide (FZO), zinc aluminum oxide (AZO), and combinations thereof. As another example, the metal oxide may include SiO ₂ , Sn0 ₂ , Ti0 ₂ , Al ₂ O ₃ , Zr0 ₂ , or a combination of two or more thereof. The core material may be in electrophoretic communication with the electrically conductive substrate. This allows electrons to move between the core material to the electrically conductive substrate, allowing current to flow through the electrodes.

According to one embodiment, any suitable shell material may be used. Illustratively, it may include Ti0 ₂ , Al ₂ O ₃ , ZnO, and combinations thereof. Optionally, the shell material comprises a semiconducting or insulating metal oxide material, while the core material may comprise a conductive or more conductive material, preferably the shell material is a semiconducting material. In some cases, the core material has a more positive conduction band potential than the conduction band potential of the shell material in order for electron transfer to occur. For example, the core material conduction band potential may be at least about 0.2 V, at least about 0.3 V, or at least about 0.4 V more positive than the conduction band potential of the shell material. In a preferred embodiment, the core-shell nanoparticles may have a structure in which the core is SnO ₂ and the shell is TiO ₂ . Referring to FIG. 6 , according to the nanoparticles composed of SnO ₂ core and TiO ₂ shell, it can be seen that the photocurrent of the photoelectric device is significantly improved due to the core-shell effect compared to nanoparticles composed of TiO ₂ . In the case of a core-shell structure, there is an advantage of having the advantages of a core and a shell at the same time. In particular, since the SnO ₂ core quickly moves electrons to the electrode, the photocurrent of the photoelectric device is significantly improved, and the TiO ₂ shell uses light by reducing the BET (Back Electron Transfer) process that prevents the injected electrons from returning to their original positions. Thus, it is possible to maximize the efficiency by preventing the injected electrons from returning to their original positions. For this reason, SnO ₂ core/TiO ₂ shell is used, and if the core-shell is not used, a similar phenomenon can be obtained, but the photoelectric conversion performance is poor. Therefore, according to the present invention, by using the SnO ₂ core/TiO ₂ shell, high efficiency can be achieved.

According to one embodiment, the shell material may partially surround the core material, or the shell material may completely comprise the core material.

According to one embodiment, the core-shell nanoparticles can be of any suitable size. The core material may optionally form nanoparticles of dimensions up to about 1 pm, after which a shell material may be formed or deposited thereon. Illustratively, having a dimension of at least about 1 nm, at least about 10 nm, at least about 20 nm, at least about 50 nm, at least about 100 nm, at least about 250 nm, at least about 500 nm, or at least about 800 nm To provide a core material in the form of nanoparticles. In another exemplary embodiment, the core material nanoparticles are about 5 nm or less, about 15 nm or less, about 25 nm or less, about 75 nm or less, about 150 nm or less, about 300 nm or less, about 600 nm or less, about 900 nm or less, or about 1 μm or less.

According to one embodiment, the thickness of the shell material on the core material may be any suitable thickness. The thickness can be determined by balancing the need for efficient forward electron transfer from the excited chromophore layer with the need to suppress reverse electron transfer from the nanoparticles to the oxidized chromophore layer. Illustratively, the thickness of the shell material may be at least about 1 nm, at least about 2 nm, at least about 3 nm, at least about 5 nm, at least about 10 nm, at least about 15 nm, at least about 20 nm, or at least about 50 nm. have. In another example, the thickness of the shell material is about 1 nm or less, about 2 nm or less, about 3 nm or less, about 5 nm or less, about 10 nm or less, about 15 nm or less, about 20 nm or less, or about 50 nm or less. may be below.

According to one embodiment, the thickness of the core-shell nanoparticle layer on the substrate may be any suitable thickness. Illustratively, the thickness of the core-shell nanoparticle layer is about 0.5 μm or less, about 1 μm or less, about 2 μm or less, about 5 μm or less, about 10 μm or less, about 20 μm or less, about 50 μm or less, about 100 μm or less, or about 1000 μm or less. In another exemplary embodiment, the thickness of the core-shell nanoparticle layer is about 0.5 μm or more, about 1 μm or more, about 2 μm or more, about 5 μm or more, about 10 μm or more, about 20 μm or more, about 50 μm or more, at least about 100 μm, or at least about 1000 μm.

FIG. 5 is a view showing a comparison of photostability and loading ratio dependence of a multilayer molecular assembly according to an embodiment of the present invention. It shows better stability than the partially loaded sample, Figure 5 (b) shows the stability of the fully-loaded sample at various pH, and Figure 5 (c) is the self-protection (self- It shows the robustness and stability due to the protecting) effect. That is, while the photostability is improved, the organic dye serves to prevent desorption by stabilizing the surface of the semiconductor metal oxide.

(Example)

FTO|TiO ₂ -terthiop-Ru(thiop)

After dissolving the terthiop (organic dye) material in MeOH, the FTO|TiO ₂ electrode was immersed for 5 hours and loaded onto the electrode surface. An electrooxidative polymerization reaction of a Ru (thiop) material is performed on the organic dye-loaded electrode.

electrooxidative polymerization

Dissolve 0.1M TBAP in 1000μM Ru dye compound in ACN and proceed with the experiment with three electrodes (Reference Electrode: SCE / Working Electrode: FTO|TiO ₂ / Counter Electrode: Pt). was assembled.

Electric reduction polymerization

By dissolving 0.1M TBAP in 1000μM Ru catalyst compound in ACN, the experiment was carried out with three electrodes (Reference Electrode: SCE / Working Electrode: FTO|TiO _2- Ru Dye / Counter Electrode: Pt). The dye and the metal catalyst were assembled.

(Comparative example)

FTO|TiO ₂ -RuP

-(PO₃H₂)2bpy)](Cl)₂) 물질을 증류수에 용해시킨 후 FTO|TiO₂ 전극을 5시간 동안 담궈 전극 표면에 로딩시킨다.RuP ([Ru(bpy)2(4,4)

-(PO ₃ H ₂ )2bpy)](Cl) ₂ ) After dissolving the material in distilled water, the FTO|TiO ₂ electrode is immersed for 5 hours and loaded on the electrode surface.

(Experimental example)

FTO|TiO ₂ -RuP and FTO|TiO ₂ Comparison of photocurrent of -terthiop-Ru(thiop)

Referring to FIG. 7 , a photocurrent having a light on/off period of 30 seconds was applied with a 0.1V bias based on the SCE electrode (pH 1: 0.1M HClO ₄ , pH 7,12: 0.1M Na ₃ PO ₄ /HCl + 0.4 M NaClO ₄ ).

Referring to the photocurrent graphs at pH 1, 7, and 12 of FIG. 7 , it can be seen that the Ru dye according to an embodiment has greater surface stability than RuP.

FTO|TiO ₂ -RuP and FTO|TiO ₂ Comparison of photostability of -terthiop-Ru(thiop)

For photostability comparison, it was specified through photocurrent response. A photocurrent with a period of 60-900 sec was applied with 0.1V bias relative to the SCE electrode in 0.4M NaClO ₄ , 0.1M phosphate buffer at pH 7.

Referring to FIG. 8 , it can be seen that the photostability of FTO|TiO ₂ -terthiop-Ru(thiop) according to an embodiment is superior to that of FTO|TiO ₂ -RuP.

FTO|TiO ₂ -RuP, FTO|TiO ₂ -terthiop-Ru(thiop), FTO|TiO ₂ Comparison of photocurrents of -terthiop-Ru(thiop)-Ru catalysts

Referring to FIG. 9 , a photocurrent having a light on/off period of 30 seconds was applied with a 0.1V bias based on the SCE electrode (pH 1: 0.1M HClO ₄ , pH 7,12: 0.1M Na ₃ PO ₄ /HCl + 0.4 M NaClO ₄ ).

Referring to the photocurrent graphs at pH 1, 7 and 12 in FIG. 9 , it can be seen that the terthiop-assembly according to an embodiment has greater surface stability than RuP.

photoelectrolysis experiment

Referring to FIG. 10( a ), current-time tracking was performed under the light of 60-900s with 0.2V bias based on the SCE electrode. Referring to FIG. 10( b ), the current-time response in the FTO collector electrode 1 mm away from the photoanode biased to −0.85 V with respect to the SCE (dissolved O ₂ sensing) of the electrode was measured. FTO|TiO ₂ -terthiop-Ru(thiop) according to an embodiment was applied to the photoanode.

As a result of the photoelectrolysis experiment, it was confirmed that the electrochemical device including the multilayer molecular assembly according to an embodiment generates oxygen in the Collector-Generator battery with a high Faraday efficiency of 75%.

In the above, the technology disclosed in the present specification has been described in detail with reference to preferred embodiments, but the technical spirit of the present invention is not limited to the above embodiments, and those of ordinary skill in the art within the scope of the technical spirit of the present invention Various modifications and changes are possible by the person.

Claims (11)

a protective layer formed on a metal oxide and made of an organic material;
The protective layer and the first electrochemically polymerized color development layer; and
It is in electron transfer communication with the color development layer, and includes a catalyst layer that is electrochemically polymerized with the color development layer,
The first electrochemical polymerization is an electro-oxidation polymerization (Oxidation Eletropolymerization),
The second electrochemical polymerization is a multilayer molecular assembly, characterized in that the reduction polymerization (Reduction Eletropolymerization). The method of claim 1,
wherein the metal oxide comprises core-shell nanoparticles comprising a core material surrounded at least partially by a shell material. 3. The method of claim 2,
The metal oxide is tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), antimony tin oxide (ATO), gallium zinc oxide (GZO), indium zinc oxide (IZO), copper aluminum oxide (CAO) , Multilayer molecular assembly comprising at least one selected from the group consisting of fluorine-doped zinc oxide (FZO), zinc aluminum oxide (AZO), and combinations thereof. 3. The method of claim 2,
The core material is SnO ₂ , and the shell material is TiO ₂ , characterized in that the multilayer molecular assembly. The method of claim 1,
The organic material is pyrrole, bipyrrole, terpyrrol, thiophene, bithiophene, terthiophene, azulene, pyrene. and carbazole (Carbazole), characterized in that it comprises at least one selected from the group consisting of, a multilayer molecular assembly. The method of claim 1,
The chromophoric layer comprises a metal-ligand coordination complex,
The metal is silicon (Si), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), osmium (Os), copper (Cu), iridium (Ir), iron (Fe), cobalt ( Co), nickel (Ni), manganese (Mn), magnesium (Mg) and contains at least one selected from the group consisting of ruthenium (Ru),
The ligand is a multilayer molecular assembly, characterized in that it comprises a bi-pyridine compound represented by the following formula (1):
[Formula 1]

Here, R ₁ and R ₂ are each independently hydrogen (H), halogen, carboxyl group, sulfonic acid group, thiophene group, pyrrole group, amide group, ester group, acetyl group, siloxane group, alkyl group having 1 to 10 carbon atoms, carbon number At least one selected from the group consisting of an alkylene group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an oxyalkylene group having 1 to 10 carbon atoms, a fluorinated alkyl group having 1 to 10 carbon atoms, and an arylalkyl group having 4 to 20 carbon atoms. do. The method of claim 1,
The catalyst layer is a multilayer molecular assembly, characterized in that it comprises a compound represented by the following formula (2), a salt thereof, or a derivative thereof:
[Formula 2]
Ru(2,2′-bipyridine-6,6′-dicarboxylate)(R ₃ )(R ₄ )
Here, R ₃ and R ₄ each independently include at least one selected from the group consisting of pyridine, 4-vinyl pyridine, pyridin-4-yl methyl phosphonic acid, and isoquinoline. counter electrode;
electrolyte; and
comprising an electrode;
The electrode is characterized in that it comprises the multilayer molecular assembly according to any one of claims 1 to 7, an electrochemical device. 9. The method of claim 8,
The electrochemical device is a dye-sensitized photoelectrosynthesis cell (Dye-Sensitized Photoelectrosynthesis Cell, DSPEC), characterized in that the electrochemical device. fixing a protective layer on the metal oxide surface;
bonding the protective layer and the color-developing layer through a first electrochemical polymerization; and
Combining the chromogenic layer and the catalyst layer by a second electrochemical polymerization,
The first electrochemical polymerization is an electro-oxidation polymerization (Oxidation Eletropolymerization),
The second electrochemical polymerization is a method of manufacturing a multilayer molecular assembly, characterized in that the reduction polymerization (Reduction Eletropolymerization). delete

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