KR101013151B1 - Photosensitized electrode and preparing method thereof - Google Patents

Abstract

The present invention relates to a photosensitive electrode and a method for manufacturing the same, and more particularly, to excellent electron transfer efficiency even by performing a low temperature coating process (100 ° C. or less) without performing a conventional high temperature heat treatment (450 to 500 ° C.). It is possible to provide a photosensitive electrode and a manufacturing method thereof which are very useful as electrodes of a solar cell or a photosensitive sensor.

Low Temperature Coating Process, Photosensitive Electrode, Solar Cell

Description

Photosensitive electrode and its manufacturing method {PHOTOSENSITIZED ELECTRODE AND PREPARING METHOD THEREOF}

The present invention can obtain excellent electron transfer efficiency even by performing a low temperature coating process (100 ° C. or less) without undergoing a conventional high temperature heat treatment (450 to 500 ° C.), which is very useful as an electrode of a solar cell or a photosensitive sensor. It relates to a photosensitive electrode and a manufacturing method thereof.

Recently, research into using clean energy such as solar energy as a new energy source instead of chemical fuels such as coal and petroleum is being actively conducted worldwide. Of these, solar cells are devices that convert solar energy directly into electrical energy. Conventional photovoltaic power generation exposes a solar cell, a pn junction type semiconductor, having a structure in which p-type and n-type semiconductors are bonded to produce electrons with (+) electricity and holes with (-) electricity. Then, by moving the electrons and holes to the electrode to generate an electromotive force.

On the other hand, dye-sensitized solar cells, unlike silicon solar cells, are mainly composed of photosensitive dye molecules capable of absorbing visible light to produce electron-hole pairs, and transition metal oxides for transferring the generated electrons. It is a photoelectrochemical solar cell made of a constituent material. A representative example of the dye-sensitized solar cells known so far was published in 1991 by Gratzel et al. The solar cell by Gratzel et al. Is composed of a semiconductor electrode composed of nanoparticle titanium dioxide (TiO ₂ ) coated with dye molecules, a platinum electrode, and an electrolyte filled therebetween. Such a battery has been attracting attention because it can be replaced with a conventional solar cell because the manufacturing cost per power is lower than that of a conventional silicon solar cell.

A semiconductor electrode of a general nanoparticle oxide is completed by coating a colloidal solution of nanoparticle oxide on a conductive glass substrate and heating it at an electric furnace of 450 to 500 ° C. The purpose of heating is to increase the electrical contact of the nanoparticle oxides and to remove the polymer added during the preparation of the colloidal solution to improve the photoelectric properties. The heating temperature of 450 to 500 ° C. is relatively high, but the glass substrate is a material that can be used without deformation even at such a high temperature. However, due to the nature of the glass substrate, it is impossible to bend the manufactured solar cell, so the plastic substrate and the need to bend the application field has been excluded.

On the other hand, in order to adsorb dye molecules on the particle surface of the nanoparticle oxide, the dyes were limited to those having functional groups such as COOH or PO ₃ H. Even though such dyes are used in a limited way, the adsorption stability is greatly reduced. , Chemical sensors, and biosensors are difficult to incorporate into practical technologies.

Dye-sensitized solar cell development research has been an area of increasing interest since the 2000s. According to the results studied so far, a colloidal solution prepared by dispersing nanoparticle oxides in a solvent such as ethanol which can be volatilized at low temperature is applied, and then heat treated at a temperature of about 100 ° C. to form a nanoparticle oxide layer, and an organic dispersant. After coating the colloidal solution prepared using, the nanoparticle oxide layer was formed by removing the dispersant in parallel with ultraviolet irradiation and heating at a temperature of about 100 ° C. However, the above studies show very low electron transfer efficiency (ie energy conversion efficiency) compared to conventional dye-sensitized solar cells using glass substrates.

According to one embodiment of the present invention, in the manufacture of the photosensitive electrode, since the heat treatment is performed at a high temperature, there is a problem that the use of the plastic substrate is restricted, and the electron transfer efficiency is very low when the high temperature heat treatment is not performed. It is to solve the problem.

In addition, an embodiment of the present invention is to solve the problem of poor adsorption stability when adsorbing dye molecules on the surface of the inorganic nanoparticles.

In order to solve the above problems, an embodiment of the present invention provides a photosensitive electrode comprising (a) inorganic nanoparticles, (b) polymer, and (c) carbon nanotubes.

In addition, an embodiment of the present invention provides a solar cell or a photosensitive sensor including the photosensitive electrode.

In addition, one embodiment of the present invention (a) inorganic nanoparticles, (b) a polymer, and (c) a carbon nanotube in a solvent mixed with a solvent to prepare a slurry, and prepared in the first step on the substrate After applying the prepared slurry at room temperature, and dried at a temperature of 20 to 100 ℃ provides a method for producing a photosensitive electrode comprising a two-step to produce a photosensitive electrode.

One embodiment of the present invention has an effect that can be obtained excellent electron transfer efficiency even by performing a low temperature coating process (100 ℃ or less) without undergoing a conventional high temperature heat treatment (450 to 500 ℃) process.

In addition, an embodiment of the present invention has the effect of improving the adsorption stability of the dye molecules on the surface of the inorganic nanoparticles by introducing a polymer.

Therefore, one embodiment of the present invention has an effect that can be very usefully applied to the electrode of the solar cell or photosensitive sensor.

According to one embodiment of the invention, the inorganic nanoparticles (a) after the inorganic nanoparticles are supported in the (b) polymer solution, and (c) a carbon-based material having a high electrical conductivity is introduced therein to separate the inorganic nanoparticles present in the polymer. By connecting them, it is possible to manufacture the photosensitive electrode at low temperature. In particular, the photosensitive electrode may further improve light efficiency by adding and adsorbing (d) a photoactivating material that absorbs light energy to give up an electron in an excited state.

In the present invention, unless otherwise specified, the term "nanoparticle" means a particle of several nanometers to several hundred nanometers, and more preferably, a particle having a particle size in the range of 1 to 1000 nm.

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

The (a) inorganic oxide nanoparticles are not particularly limited to transparent conductive materials generally used in the art. More specifically, Ti, Zr, Sr, Zn, In, Yr, La, V, Mo, W, Sn, Nb, Mg, Al, Y, Sc, Sm, Ga, In, Cd, Se, TiSr, Ag, Oxides, sulfides, or halides of metals selected from the group consisting of Pb, Bi, and mixtures thereof can be used. In particular, the titanium (Ti) oxide nanoparticles can be used more preferably, titanium dioxide (TiO ₂ ) nanoparticles can be used more preferably.

(D) Visible light-activated semiconductor nanoparticles having a bandgap smaller than that of titanium dioxide, more specifically, CdS or CdSe Can be used more preferably.

At this time, the (a) inorganic oxide nanoparticles are advantageous to have a large surface area for introducing electrons from the photoactivating material, has a surface area of 200 to 300 m ² / g, to take advantage of the conductivity inside the semiconductor nanoparticles For this purpose, it is preferable to use nanoparticles having a particle diameter of 1 to 100 nm.

In order to use the photosensitive electrode according to the present invention for producing hydrogen, the conduction band of the semiconductor nanoparticles should be positioned higher than the hydrogen generation energy level.

The (b) polymer is not particularly limited, and an ion conductive polymer may be preferably used. More specifically, polyperfluorosulfonic acid having excellent physical and chemical stability, polyalkyl ether having 1 to 20 carbon atoms, polyether ether ketone, polyether sulfone, polyimide, polyvinyl alcohol, polyethyleneimine, and mixtures thereof Can be selected from. More preferably, it is preferable to use polyperfluorosulfonic acid, and a typical example of the polyperfluorosulfonic acid may be Nafion (Dupont).

According to one embodiment of the present invention, by replacing the anionic functional group or cationic functional group in the polymer having excellent physicochemical stability, it can be used more preferably. (D) It is preferable to substitute the functional group with a functional group having a charge opposite to that of the photoactivating material which absorbs (d) the light energy to give an excited electron. As a result, the (d) light energy can be absorbed to facilitate the adsorption of the photoactivating material that emits the electrons in the excited state.

Specific examples of the polymer having an anionic functional group include a polymer including an ion conductive group of -SO ₃ M, -COOM, -OM, or -PO ₃ HM (wherein M represents a hydrogen atom, ammonium or an alkali metal). Can be used. For example, a polymer having -SO ₃ M may be a polymer having a substituent such as a carboxyl group, a hydroxy group or an amine group, and sulfosuccinic acid, sulfosalicylic acid, sulfoacetic acid, and sulfophthalic acid. acid), and hydroquinonesulfonic acid may be prepared by crosslinking a compound including an ion conductive group selected from the group consisting of.

In addition, specific examples of the polymer having a cationic functional group may be a polymer including an ion conductive group of -NH ₂ , -CONH ₂ . Specific examples thereof may include polyethyleneimine.

In order to use the light energy, (d) it is preferable that an electrical and chemical interaction is made between the light activating material and the polymer so that the light activating material that absorbs the light energy to give up the excited electrons is adsorbed on the polymer. For example, in order to adsorb a photoactive material having a positive charge using electrostatic attraction, (b) the polymer is preferably a negative charge. The Nafion polymer described above is very useful because it has a strong negative charge and can effectively adsorb a photoactive material having a positive charge. In particular, when the photosensitive electrode according to one embodiment of the present invention is used as a photocathode for generating hydrogen, an ion conductive polymer having a negative charge such as Nafion is used because hydrogen cations can be freely passed through. It is very useful to do

The (c) carbon-based material is introduced to further improve the conductivity of the electrode, the photoactivating material (d) adsorbed on the polymer is excited by light and transfers the excited electrons to the conduction band of the inorganic oxide nanoparticles, The electrons thus transferred are used to efficiently transfer the carbon-based material to the surface of the conductive substrate. The carbonaceous material may be selected from the group consisting of carbon nanotubes, graphite, carbon nanofibers, fullerenes, nanorods, diamond like carbon (DLC), graphene, and mixtures thereof, and even more. It is preferable to use carbon nanotubes.

In particular, the carbon nanotubes are generally used in the art, but are not particularly limited, and in order to use them as conductors in the polymer composite, those having excellent conductivity may be used. More specifically, carbon nanotubes can be classified according to the number of bonds of carbon atoms constituting the wall. Single-walled carbon nanotubes have the best electrical conductivity and thermal conductivity in the form of a tube having one wall of carbon atoms. Double-walled nanotubes with two carbon atoms are excellent in electrical conductivity and mechanical properties.Multi-walled carbon nanotubes have several layers of carbon atoms in one tube. It is easy to manufacture and has a wide range of applications. In the present invention, more preferably, single-walled carbon nanotubes having excellent electrical conductivity are preferred, and even more preferably, metallic single-walled carbon nanotubes are preferred.

On the other hand, the photosensitive electrode may include (a) 10 to 200 parts by weight of the polymer, and (c) 0.1 to 100 parts by weight of the carbon-based material based on 100 parts by weight of inorganic nanoparticles. More preferably, (a) 10 to 150 parts by weight of the polymer, and (c) 0.1 to 50 parts by weight of the carbon-based material, based on 100 parts by weight of the inorganic nanoparticles. Even more preferably, it may comprise (a) 10 to 100 parts by weight of polymer, and (c) 0.1 to 20 parts by weight of carbon-based material, based on 100 parts by weight of inorganic nanoparticles.

At this time, the inorganic nanoparticles (a) and the polymer (b) to improve the electrical conductivity by the electrode formation properties such as peeling the polymer composite coated on the electrode and the distance between the particles of the conductive material, the carbon nano Tube (c) is more preferably made of the above content range in order to improve the conductivity of the metal oxide nanoparticles to improve the electrical conductivity, and to reduce the problem of light efficiency due to the original color of the carbon nanotubes.

The photosensitive electrode according to the present invention may further comprise (d) a photoactivating material that absorbs light energy to give up an electron in an excited state.

(D) The photoactivating material absorbing the light energy to give up the electrons in the excited state has the visible light activity by adsorbing to the inorganic nanoparticles, conventionally the adsorption stability to the inorganic nanoparticles of such photoactivating material is greatly deteriorated There was a difficulty in incorporating practical technology such as a battery, and in order to improve the adsorption stability, there was a disadvantage in that it was limited to a material including a functional group such as -COOH or -PO ₃ H. However, in the present invention, the polymer assists in the adsorption of inorganic oxide nanoparticles and a photoactivating material that absorbs light energy to give up an electron in an excited state, thereby making it possible to use various dyes as photosensitive agents.

Therefore, the photo-activating material (d) according to the present invention absorbs the light energy to give up the electrons in the excited state is not particularly limited to those commonly used in the art, but more specifically, when applied to solar cells, Al), platinum (Pt), palladium (Pd), europium (Eu), lead (Pb), iridium (Ir), ruthenium (Ru), and combinations thereof are selected from the group consisting of metal complexes, organic pigments , And mixtures thereof. In addition, dyes that may be found in wastewater, more specifically, azo dyes used in the textile dyeing industry may also be used as photo-activating materials that absorb (d) the light energy and give off electrons in an excited state, but are not limited thereto. Do not.

In addition, the photosensitive electrode may further comprise (d) 1 to 100 parts by weight of a photoactivating material that absorbs the light energy to give up the electrons in the excited state. More preferably, it is preferable to further include 1 to 50 parts by weight.

At this time, the light-activated material (d) for absorbing the light energy to give up the electrons in the excited state is more preferably made in the above content range in order to improve the light conversion characteristics and light efficiency.

When the photosensitive electrode is irradiated with light, the photocurrent rapidly improves, and when a hydrogen-generating photoelectrochemical cell is constructed using an electrode photosensitive with a photoactivating material (d) adsorbed to a polymer, electrons generated from the photosensitive electrode It is possible to obtain an effect of greatly improving the amount of hydrogen generated by moving to the platinum electrode and reducing hydrogen ions.

Therefore, the photosensitive electrode according to the embodiment of the present invention can be very usefully applied to solar cells or photosensitive electrochemical cells. In particular, since the photoactive electrode according to the embodiment of the present invention enables production at a low temperature, when applied to a polymer substrate, the battery may be freely mounted on the surface of various shapes due to its flexibility, thereby providing excellent application. In addition, such a technique may be used as a photosensitive sensor, and examples thereof include a chemical sensor or a biosensor.

In particular, the photosensitive electrode according to the embodiment of the present invention may act as a photoanode of the photosensitive electrochemical cell. When light is emitted, electrons generated from the photoanode may move to the opposite electrode through an external circuit to reduce hydrogen cations. The operating state of the photosensitive electrochemical cell is shown in FIG. 1. The electrons generated by the dye inside the photoanode are transferred to the TiO ₂ conduction band (CB) and reach the conductive substrate. The flow of electrons is greatly enhanced by carbon-based materials such as single-walled carbon nanotubes (SWCNTs) connecting titanium dioxide nanoparticles to each other.

The method of manufacturing the photosensitive electrode according to the present invention has an effect of obtaining excellent electron transfer efficiency even by performing a low temperature coating process (100 ° C. or less) without undergoing a high temperature heat treatment (450 to 500 ° C.).

The photosensitive electrode may be prepared by, for example, (a) inorganic nanoparticles, (b) polymers, and (c) a carbon-based material in a solvent, mixed with each other, to prepare a slurry, and in the first step on the substrate. After the applied slurry at room temperature, and dried at a temperature of 20 to 100 ℃ can be prepared by a method for producing a photosensitive electrode comprising a two step of producing a photosensitive electrode.

At this time, in the step 1 of preparing the slurry, (d) a photoactivating material that absorbs the light energy and gives out the electrons in the excited state may be further added, put into a solvent, and mixed.

In addition, the method of manufacturing the photosensitive electrode (2) after the second step of manufacturing the photosensitive electrode to absorb the (b) photo-energy material that emits the electrons in the excited state to the (b) polymer of the photosensitive electrode It may be prepared by a method of manufacturing a photosensitive electrode further comprising three steps.

In the method of manufacturing the photosensitive electrode, (a) inorganic nanoparticles, (b) polymers, (c) carbon nanotubes, and (d) a kind of photoactivating material that absorbs the light energy to give an electron in the excited state , Content, physical properties and the like are as described while explaining the photosensitive electrode.

The solvent is generally used in the art, and is not particularly limited. For example, acetone, methanol, ethanol, isopropyl alcohol, n-propyl alcohol, butyl alcohol, dimethylacetamide (DMAc), dimethyl formamide , Dimethyl sulfoxide (DMSO), N-methyl-2-pyrrolidone (NMP), tetrahydrofuran (THF), tetrabutyl acetate, n-butyl acetate, m-cresol, toluene, ethylene glycol (EG), γ Organic solvents such as butyrolactone and hexafluoroisopropanol (HFIP) and water may be used alone or in combination.

In addition, the slurry coating method is generally used in the art, and is not particularly limited. For example, spin coating, spray coating, screen printing, doctor blading, ink jetting, or the like may be used.

The substrate is not particularly limited as long as it has transparency, and specifically, a glass or plastic substrate can be used. In order to improve the conductivity, the transparent substrate may be formed of indium tin oxide (ITO), florin doped tin oxide (FTO), ZnO-Ga ₂ O ₃ , ZnO-Al ₂ O ₃ , SnO ₂ -Sb ₂ O _3, and the like. It is more preferable to use a transparent substrate coated with a conductive material.

Hereinafter, the present invention will be described in more detail with reference to the following examples, which should not be construed as limiting the invention thereto.

[Production of Photosensitive Electrode]

Example 1

5 g of titanium dioxide nanoparticles were added to 15 g of a 5 wt% Nafion polymer solution in which the solvent was water and alcohol, followed by stirring for 2 days or more to uniformly disperse the particles on the solution (solution 1).

In the same manner, 0.2 g of carbon nanotubes were also dispersed in 19.8 g of a 5 wt% Nafion polymer solution by stirring for 2 days (solution 2).

2 g of solution 1 and 5 g of solution 2 were mixed, coated on a conductive substrate by a doctor blading method, and dried in air at room temperature. The dried electrode was placed in 20 mL of 0.5 mM ruthenium dye solution (Tris (2,2'-bipyridyl) dichloro-ruthenium (II) hexahydrate (CAD 50525-27-4), Aldrich, 224758-1G) in ethanol for 12 hours. Was deposited to adsorb the dye onto the Nafion polymer and dried again to prepare the electrode. At this time, the dye was adsorbed 24.1 parts by weight based on 100 parts by weight of titanium dioxide.

At this time, the (a) Nafion polymer; (b) solution 1 (titanium dioxide nanoparticles + Nafion polymer); And (c) the photosensitive electrode according to Example 1 of the present invention was observed with a scanning electron microscope (SEM), and is shown in FIG. 2.

As a result of SEM observation, it was confirmed that the photosensitive electrode according to the present invention was well interconnected by the carbon nanotubes in the titanium dioxide nanoparticles in the Nafion polymer as compared to the solution 1 in which the carbon nanotubes were not added. As a result, it was determined that the photosensitive electrode according to the present invention had excellent electron transfer characteristics.

In addition, the solution 1 (titanium dioxide nanoparticles + Nafion polymer); Mixed solution of solution 1 and 2 (titanium dioxide nanoparticles + carbon nanotubes + Nafion polymer); And 300 to 700 nm using a UV-Vis spectrophotometer (Shimadzu, UV-2401PC) for the photosensitive electrode (titanium dioxide nanoparticles + carbon nanotubes + Nafion polymer + dyes) according to Example 1 according to the present invention The absorbance of the range was measured and shown in FIG. 3.

As a result of absorbance observation, it was confirmed that the light absorbency of the electrode was greatly increased by adding carbon nanotubes, and the visible light absorbency of the electrode was further increased by adsorbing the dye as compared with the case where the dye was not adsorbed. there was. This means that even if the photosensitive electrode contains a photo-activating material that absorbs (d) light energy such as dye and emits electrons in the excited state, it is not lost by the black carbon nanotubes, but still has excellent visible light absorption. You can see that you can have.

[Manufacture of Solar Cell]

Example 2

A solar cell was manufactured using the electrode prepared in Example 1. The electrode was placed in front of the glass container, and the platinum wire used as the counter electrode and the Ag / AgCl electrode serving as the reference electrode were placed. 40 mL of 50 mM ethylenediaminetetraacetic acid (EDTA) aqueous solution was injected into the reactor as an electron donor capable of re-reducing the oxidized dye after electron transfer, and hydrogen generated from the counter electrode was accumulated in the gas phase of the upper part of the reactor. . The reactor was sealed and blown with nitrogen for 15 minutes to remove oxygen present in the solution, preventing the oxygen molecules from accepting electrons on the counter electrode.

Gas was collected from the gaseous part in the upper layer of the solar cell, and the amount of hydrogen produced according to time change after light irradiation was investigated using gas chromatography (Agilient, 6890A).

In addition, using the prepared electrode as a working electrode, Ag / AgCl as a reference electrode, a platinum electrode as a counter electrode, the current generated by applying a voltage of 0.4 V to the reference electrode to the working electrode potentiostat (Gamry, Reference 600 It is shown in Figure 4 by using a).

Photosensitive electrode with controlled carbon nanotube content

Examples 3-8

2 g of titanium dioxide nanoparticles were added to 18 g of a 5 wt% Nafion polymer solution in which the solvent was water and alcohol, followed by stirring for 2 days or more to uniformly disperse the particles on the solution (solution 1).

In the same manner, 0.2 g of carbon nanotubes were also dispersed in 19.8 g of a 5 wt% Nafion polymer solution by stirring for 2 days (solution 2).

Mixing of Solution 1 and Solution 2 was performed so that CNT / (CNT + TIO ₂ ) was 0.8, 1.3, 2.1, 3.2, 4.7 and 7.1 wt% (Examples 3 to 8) and coated on the conductive substrate by a doctor blading method. And dried in air at room temperature.

This solution was coated on a conductive substrate by a doctor blading method and dried in air at room temperature. The dried electrode was immersed in 20 mL of a 0.5 mM ruthenium dye solution in ethanol for 12 hours to adsorb the dye to the Nafion polymer and dried again.

The solar cell was manufactured using the electrode. The electrode was placed in front of the glass container, and the platinum wire used as the counter electrode and the Ag / AgCl electrode serving as the reference electrode were placed. 40 mL of 50 mM ethylenediaminetetraacetic acid (EDTA) aqueous solution was injected into the reactor as an electron donor capable of re-reducing the oxidized dye after electron transfer. . The reactor was sealed and blown with nitrogen for 15 minutes to remove oxygen present in the solution, preventing the oxygen molecules from accepting electrons on the counter electrode.

Gas was collected from the gas phase portion present in the upper layer of the solar cell, and hydrogen production was investigated after 1 hour of light irradiation using gas chromatography (Agilient, 6890A), and the results are shown in Table 1 below.

Electrode without Titanium Dioxide Nanoparticles in Nafion Polymer

Comparative Example 1

0.2 g of carbon nanotubes were added to 19.8 g of a 5 wt% Nafion polymer solution in which the solvent was water and alcohol, and then stirred and dispersed for 2 days.

This solution was coated on a conductive substrate by a doctor blading method and dried in air at room temperature. The dried electrode was immersed in 20 mL of 0.5 mM ruthenium dye solution (Tris (2,2'-bipyridyl) dichloro-ruthenium (II) hexahydrate (CAD 50525-27-4) for 12 hours) in which the dried electrode was Nafion. The electrode was prepared by adsorbing to polymer and drying again.

The solar cell was manufactured using the electrode. The electrode was placed in front of the glass container, and the platinum wire used as the counter electrode and the Ag / AgCl electrode serving as the reference electrode were placed. Into the reactor, 40 mL of 50 mM aqueous solution of EDTA, which can re-oxidize the oxidized dye after electron transfer, was injected, and hydrogen generated from the opposite electrode was accumulated in the gas phase of the upper part of the reactor. The reactor was sealed and blown with nitrogen for 15 minutes to remove oxygen present in the solution, preventing the oxygen molecules from accepting electrons on the counter electrode.

Gas was collected in the gas phase portion present in the upper part of the solar cell, and gas generation (Agilient, 6890A) was used to examine the hydrogen production amount after 1 hour of light irradiation. As a result, the hydrogen production amount was found to be 0 μmol / h.

Electrode without Carbon Nanotube in Nafion Polymer

Comparative Example 2

2 g of titanium dioxide nanoparticles were added to 18 g of a 5 wt% Nafion polymer solution in which the solvent was water and alcohol, followed by stirring for 2 days or more to uniformly disperse the particles on the solution (solution 1).

This solution was coated on a conductive substrate by a doctor blading method and dried in air at room temperature. The dried electrode was immersed in 20 mL of a 0.5 mM ruthenium dye solution in ethanol for 12 hours to adsorb the dye to the Nafion polymer and dried again.

The solar cell was manufactured using the electrode. The electrode was placed in front of the glass container, and the platinum wire used as the counter electrode and the Ag / AgCl electrode serving as the reference electrode were placed. Into the reactor, 40 mL of an electron donor (EDTA) aqueous solution capable of re-reducing the oxidized dye after electron transfer was injected, and hydrogen generated from the counter electrode was accumulated in the gas phase of the upper part of the reactor. The reactor was sealed and blown with nitrogen for 15 minutes to remove oxygen present in the solution, preventing the oxygen molecules from accepting electrons on the counter electrode.

Gas was collected in the gaseous phase portion present in the upper layer of the solar cell, and gas generation (Agilient, 6890A) was used to investigate hydrogen production according to the time change after irradiation with light, and is shown in FIG. 4. In addition, as a result of examining the hydrogen production amount after 1 hour of light irradiation, it was confirmed that the hydrogen production amount was 0.01 μmol / h.

In addition, using the prepared electrode as a working electrode, Ag / AgCl as a reference electrode, a platinum electrode as a counter electrode and the current generated by applying a voltage of 0.4V to the reference electrode to the working electrode potentiostat (Gamry, Reference 600 It is shown in Figure 4 by using a).

As shown in FIG. 4, as a result of measuring the amount of photocurrent and hydrogen generated over time, the photosensitive electrode of Example 2 according to the present invention is generated after irradiating visible light as compared with Comparative Example 2 in which carbon nanotubes do not exist. It was confirmed that the photocurrent and the hydrogen production amount were excellent.

division Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 CNT / (CNT + TIO ₂ ) (% by weight) 0.8 1.3 2.1 3.2 4.7 7.1 Hydrogen generation amount (μmol / h) 1.96 3.45 3.79 3.00 2.20 1.70

As shown in Table 1, when changing the content ratio of titanium dioxide and carbon nanotubes in the electrodes prepared in Examples 3 to 8, the amount of hydrogen generation is maximized, Comparative Example 1 that does not exist titanium dioxide nanoparticles It was confirmed that hydrogen is hardly generated in the solar cell manufactured in Comparative Example 2, in which no carbon nanotubes exist.

This indicates that both titanium dioxide nanoparticles and carbon nanotubes play an important role in electron transport in the electrode. Electrons generated from dyes excited by light are transferred to titanium dioxide nanoparticles rather than carbon nanotubes. However, in the absence of carbon nanotubes, electron transfer between the titanium dioxide nanoparticles is not easy, resulting in a decrease in current generation and hydrogen production. If the content of carbon nanotubes is too small, carbon nanotubes cannot connect the titanium dioxide nanoparticles, so the electron transfer efficiency may not be sufficient. If the content of carbon nanotubes is too high, the carbon nanotubes are rather light blocked. Because of the effect, the visible light absorption by the dye may be reduced and the amount of hydrogen production may not be sufficient.

Photosensitive electrode with controlled dye content

Examples 9-13

5 g of titanium dioxide nanoparticles were added to 15 g of a 5 wt% Nafion polymer solution in which the solvent was water and alcohol, followed by stirring for 2 days or more to uniformly disperse the particles on the solution (solution 1).

In the same manner, 0.2 g of carbon nanotubes were also dispersed in 19.8 g of a 5 wt% Nafion polymer solution by stirring for 2 days (solution 2).

2 g of solution 1 and 5 g of solution 2 were mixed, coated on a conductive substrate by a doctor blading method, and prepared by drying in air at room temperature. The dried electrode was immersed in 20 mL of a solution of ruthenium dye with ethanol for 12 hours to adsorb the dye to the Nafion polymer, but the adsorption amount of the dye was 25, 49, 88, 102, and 200 nmol / cm ² (Examples 9 to 9). 13) to change the concentration of the dye solution to adjust the dye content in the electrode to prepare an electrode by drying the electrode again.

The solar cell was manufactured using the electrode. The electrode was placed in front of the glass container, and the platinum wire used as the counter electrode and the Ag / AgCl electrode serving as the reference electrode were placed. Into the reactor, 40 mL of an electron donor (EDTA) aqueous solution capable of re-reducing the oxidized dye after electron transfer was injected, and hydrogen generated from the counter electrode was accumulated in the gas phase of the upper part of the reactor. The reactor was sealed and blown with nitrogen for 15 minutes to remove oxygen present in the solution, preventing the oxygen molecules from accepting electrons on the counter electrode.

Gas was collected in the gaseous phase present in the upper layer of the solar cell, and the amount of hydrogen produced after 1 hour of light irradiation using gas chromatography (Agilient, 6890A) was shown in Table 2 below.

division Example 9 Example 10 Example 11 Example 12 Example 13 Dye adsorption amount (nmol / cm ² ) 25 49 88 102 200 Hydrogen generation amount (μmol / h) 0.68 1.00 0.96 0.93 0.93

As shown in Table 2, when the amount of the dye in the electrode prepared in Examples 9 to 13 was increased above a certain concentration, it was confirmed that the amount of hydrogen generated also increases.

Photosensitive Electrode with Inorganic Nanoparticles

Example 14

0.2 g of cadmium sulfide nanoparticles were added to 1 g of a 5 wt% Nafion polymer solution in which the solvent was water and alcohol, followed by stirring for 2 days or more to uniformly disperse the particles on the solution (solution 1).

In the same manner, 0.2 g of carbon nanotubes were also dispersed in 19.8 g of a 5 wt% Nafion polymer solution by stirring for 2 days (solution 2).

0.5 g of solution 1 and 0.5 g of solution 2 were mixed, coated on a conductive substrate by a doctor blading method, and prepared by drying in air at room temperature.

The solar cell was manufactured using the electrode. The electrode was placed in front of the glass container, and the platinum wire used as the counter electrode and the Ag / AgCl electrode serving as the reference electrode were placed. Into the reactor, 40 mL of 100 mM aqueous solution of an EDTA (EDTA) capable of re-reducing the oxidized dye after electron transfer was injected, and hydrogen generated from the counter electrode was accumulated in the gas phase of the upper part of the reactor. The reactor was sealed and blown with nitrogen for 15 minutes to remove oxygen present in the solution, preventing the oxygen molecules from accepting electrons on the counter electrode.

Gas was collected from the gaseous phase in the upper layer of the solar cell and the amount of hydrogen produced after 1 hour of light irradiation using gas chromatography (Agilient, 6890A) was 0.22 μmol / h.

Examples 15-17

A solar cell was manufactured using the electrode according to Example 1. The electrode was placed in front of the glass container, and the platinum wire used as the counter electrode and the Ag / AgCl electrode serving as the reference electrode were placed. Inside the reactor is injected 40 mL (20, 50, and 100 mM) (Examples 15-17) of an aqueous solution of an EDTA solution which can re-oxidize the oxidized dye after electron transfer, opposite the gas phase part of the reactor Hydrogen generated at the electrode was accumulated. The reactor was sealed and blown with nitrogen for 15 minutes to remove oxygen present in the solution, thereby preventing the oxygen molecules from receiving electrons on the counter electrode.

Gas was collected in the gas phase portion present in the upper layer of the solar cell, and the hydrogen production amount was investigated after 1 hour of light irradiation using gas chromatography (Agilient, 6890A).

division Example 15 Example 16 Example 17 EDTA aqueous solution concentration (mM) 20 50 100 Hydrogen generation amount (μmol / h) 1.57 1.77 1.95

As shown in Table 3, it was confirmed that the amount of hydrogen can be increased depending on the content of the electron donor EDTA with respect to the electrolyte solution in the battery prepared in Examples 15 to 17.

All simple modifications or changes of the present invention can be easily carried out by those skilled in the art, and all such modifications or changes can be seen to be included in the scope of the present invention.

1 is a view showing an operating state of a photosensitive electrochemical cell comprising a photosensitive electrode according to the present invention.

2 is (a) Nafion polymer used in Example 1 of the present invention, (b) Solution 1 coated with titanium dioxide nanoparticles supported on the Nafion polymer, and (c) in Example 1 according to the present invention Scanning electron microscope (SEM) image of the photosensitive electrode.

3 is Solution 1 (titanium dioxide nanoparticles + Nafion polymer) used in Example 1 of the present invention; Mixed solution of solution 1 and 2 (titanium dioxide nanoparticles + carbon nanotubes + Nafion polymer); And it shows the absorbance graph for the photosensitive electrode (titanium dioxide nanoparticles + carbon nanotubes + Nafion polymer + dyes) according to Example 1 according to the present invention.

4 shows graphs of measurement results of photocurrent and hydrogen generation with time of solar cells manufactured in Example 2 and Comparative Example 2 of the present invention.

Claims (21)

A photosensitive electrode comprising a substrate and a coating layer, The coating layer is: (a) inorganic nanoparticles; (b) a polymer; And (c) carbonaceous materials; It is made, including (B) the polymer is selected from the group consisting of polyperfluorosulfonic acid, polyalkyl ether, polyether ether ketone, polyether sulfone, polyimide, polyvinyl alcohol, polyethyleneimine, and mixtures thereof, The (c) carbon-based material is selected from the group consisting of carbon nanotubes, graphite, carbon nanofibers, fullerene, nanorods, diamond-like carbon (DLC), graphene (graphene) and mixtures thereof . The method of claim 1, The coating layer is (d) A photosensitive electrode further comprising a photoactivating material that absorbs light energy and emits electrons in an excited state. The method of claim 1, The (a) inorganic nanoparticles are Ti, Zr, Sr, Zn, In, Yr, La, V, Mo, W, Sn, Nb, Mg, Al, Y, Sc, Sm, Ga, In, Cd, Se, A photosensitive electrode which is an oxide, sulfide, or halide of a metal selected from the group consisting of TiSr, Ag, Pb, Bi, and mixtures thereof. The method of claim 1, The (a) inorganic nanoparticles is a photosensitive electrode having a surface area of 200 to 300 m ² / g, and is a nanoparticle having a particle diameter of 1 to 100 nm. delete delete The method of claim 1, The coating layer is based on (a) 100 parts by weight of inorganic nanoparticles (b) 10 to 200 parts by weight of polymer; And (c) 0.1 to 100 parts by weight of carbonaceous material; Photosensitive electrode that is made, including. The method of claim 2, The coating layer is (a) 100 parts by weight of inorganic nanoparticles (d) a light-sensitive electrode that further comprises 1 to 100 parts by weight of the light-activating material for absorbing the light energy to give an electron in the excited state. A solar cell or photosensitive electrochemical cell comprising the photosensitive electrode according to any one of claims 1 to 4, 7 and 8. (a) an inorganic nanoparticle, (b) a polymer, and (c) a carbon-based material in a solvent and mixed to prepare a slurry, and Applying the slurry prepared in step 1 on a substrate at room temperature, and then drying at a temperature of 20 to 100 ℃ to prepare a photosensitive electrode As a manufacturing method of a photosensitive electrode comprising a, The polymer (b) is selected from the group consisting of polyperfluorosulfonic acid, polyalkyl ether, polyether ether ketone, polyether sulfone, polyimide, polyvinyl alcohol, polyethyleneimine, and mixtures thereof, The (c) carbon-based material is selected from the group consisting of carbon nanotubes, graphite, carbon nanofibers, fullerene, nanorods, diamond-like carbon (DLC), graphene (graphene) and mixtures thereof Manufacturing method. The method of claim 10, The first step of preparing the slurry is (d) a method of manufacturing a photosensitive electrode that absorbs light energy and further adds a photoactivating material that gives up an electron in an excited state, which is then mixed in a solvent. The method of claim 10, The method of manufacturing the photosensitive electrode includes three steps of adsorbing the photoactive material (b) on the polymer of the photosensitive electrode after (d) absorbing photoenergy to give up electrons in an excited state after two steps of manufacturing the photosensitive electrode. Method for producing a photosensitive electrode further comprising. The method of claim 10, The (a) inorganic oxide nanoparticles are Ti, Zr, Sr, Zn, In, Yr, La, V, Mo, W, Sn, Nb, Mg, Al, Y, Sc, Sm, Ga, In, Cd, Se , TiSr, Ag, Pb, Bi, and a method for producing a photosensitive electrode that is an oxide, sulfide, or halide of a metal selected from the group consisting of these. The method of claim 10, The (a) inorganic oxide nanoparticles are a nanoparticle having a surface area of 200 to 300 m ² / g, having a particle size of 1 to 100 nm. delete delete The method of claim 10, The slurry is based on (a) 100 parts by weight of inorganic nanoparticles (b) 10 to 200 parts by weight of polymer; and (c) 0.1 to 100 parts by weight of carbonaceous material; Method for producing a photosensitive electrode that is mixed in a solvent. The method of claim 11, The slurry is a mixture of (a) 100 parts by weight of inorganic nanoparticles (d) absorbing the light energy further comprises 1 to 100 parts by weight of the photo-activating material to give out the electrons in the excited state, the method of producing a photosensitive electrode . The method of claim 10, In the step 2, the photosensitive electrode is performed by applying the slurry prepared in step 1 on the substrate by a method selected from the group consisting of spin coating, spray coating, screen printing, doctor blading, and ink jetting Manufacturing method. The method of claim 1, The substrate is a photosensitive electrode that is a transparent substrate of glass or plastic. The method of claim 10, The substrate is a method of manufacturing a photosensitive electrode that is a transparent substrate of glass or plastic.

Images