KR101514276B1 - Nanocarbon-based TCO- and Pt-free counter electrodes for dye-sensitized solar cell and its method - Google Patents

Abstract

The present invention relates to a method for manufacturing an integrated conductive catalyst electrode based on nanocarbon in which carbon nanotube and graphene oxide are mixed and a catalyst electrode manufactured by the same, which is used as a catalyst electrode with conductivity by coupling a non-conductive substrate to a film based on nanocarbon in which carbon nanotube and graphene oxide are mixed. The method includes: a first step of dispersing carbon nanotube powder in a first solvent to make dispersing solution; a second step of dispersing graphene oxide powder in a second solvent to make dispersing solution; a third step of mixing respective dispersing solution formed in the first and second steps to make mixing solution; a fourth step of coupling the mixing solution of the third step to the surface of a non-conductive substrate; a fifth step of primarily drying the substrate which has gone through the fourth step; a sixth step of reducing the graphene oxide coupled to the surface of the conductive substrate which has gone through the fifth step using a water-based electrolyte in an electrochemical reduction method; and a seventh step of secondarily drying the substrate which has gone through the sixth step. Preferably, a relative electrode of a solar cell is provided. The catalyst electrode of the present invention can be applied to a flexible plastic substrate by adopting a low temperature process and achieve high performance similarly to existing platinum by a cheap single nanocarbon electrode layer formed on the substrate, thereby being used as a catalyst electrode and being supplied at a low price by reducing material costs due to no use of platinum and a conductive transparent electrode.

Description

TECHNICAL FIELD [0001] The present invention relates to a nanocarbon-based conductive catalyst electrode, a nanocarbon-based TCO- and a Pt-free counter electrode,

The present invention relates to a nanocarbon-based integrated conductive catalyst electrode, and more particularly, to a nanocarbon-based conductive electrode using a nanocarbon-based material in which a carbon nanotube and a graphene oxide are mixed, A method of fabricating a nano-carbon based integrated conductive catalyst electrode in which non-conductive low-cost carbon nanotubes and graphene oxide are mixed so that energy-saving process technology applicable to nonconductive glass or plastic can be achieved and material cost can be reduced, and Lt; / RTI >

Generally, in the case of a dye-sensitized solar cell, platinum is usually coated on a conductive substrate in consideration of electrical conductivity and resistance as a counter electrode. In recent years, various attempts have been made to replace the platinum due to the high price of platinum, and various types of electrodes are manufactured using carbon nanotubes.

Basically, as shown in FIG. 1, a conductive substrate 20 made of ITO or FTO having conductivity is vacuum deposited on a substrate 30 to be a base, thereby forming a conductive substrate. On the upper surface of the conductive substrate 20, Platinum 10 or a platinum substitute electrode 40 such as nano-carbon or a conductive polymer is further coated to be used as a catalyst electrode.

In this structure, the substrate to be the base may be a glass substrate coated with ITO or FTO having conductivity, or a metal substrate made of a metal having conductivity, and using carbon nanotubes as a substitute for platinum on the upper surface thereof do. Generally, in the above case, the production process becomes complicated, and the manufacturing cost becomes high, and the plastic substrate can not be used because high temperature heat treatment is required. Therefore, there is a problem that it can not be used in a recent lightweight flexible apparatus.

Recently, one of the most important challenges in the development of a dye-sensitized solar cell is to develop a material that can efficiently replace platinum (Pt) used as a counter electrode since the material is scarce and expensive, In order to secure economical efficiency in large scale production. A number of studies have been conducted to use graphene as an alternative to this.

However, graphene oxide is an insulator and must be subjected to a reduction process in order to be used as an electrode material. In this case, it is a very dangerous operation by mainly using chemicals having high toxicity such as hydrazine, .

Recently, graphene nanoplate (GNP) has been mainly used as an electrochemical catalyst, and GNP is coated on a conductive glass substrate to have a light transmittance of 70% or less, And the catalyst electrode is manufactured through a heat treatment at a high temperature of 300 ° C or higher. In this case, therefore, a flexible plastic substrate can not be used.

Korea Patent (Application No.: 10-2010-0092512) Korea Patent (Application No.: 10-2012-0012881) Korean Patent (Application No.: 10-2012-0026276)

Accordingly, the present invention has been made in view of the above-mentioned need, and it is an object of the present invention to provide a method of manufacturing a thin film capacitor, which uses a nano-carbon based material capable of simultaneously replacing existing expensive conductive thin film and catalyst material such as platinum, The present invention also provides a method of manufacturing a counter electrode and a counter electrode that can be applied to a flexible plastic substrate by applying a low-temperature process, and can achieve higher efficiency.

According to an aspect of the present invention, there is provided a method of manufacturing a carbon nanotube, including: a first step of dispersing a carbon nanotube powder in a first solvent to form a dispersion solution; A second step of dispersing the graphene oxide powder in a second solvent to prepare a dispersion solution; A third step of mixing the dispersion solutions formed in the first and second steps to prepare a mixed solution; A fourth step of bonding the mixed solution of the third step to the surface of the nonconductive substrate; A fifth step of first drying the substrate after the fourth step; A sixth step of reducing the graphene oxide bound to the surface of the conductive substrate after the fifth step by an electrochemical reduction method using an aqueous electrolyte; And a second step of drying the substrate after the sixth step, wherein the nano-carbon based film formed by mixing the carbon nanotubes and the graphene oxide is bonded on the nonconductive substrate to form the carbon nano- The present invention provides a method for manufacturing a nano-carbon-based integrated conductive catalyst electrode in which a tube and a graphene oxide are mixed.

Preferably, in the first step, the dispersing agent is further mixed and the first solvent is at least one selected from the group consisting of water, alcohol, acetone, dimethylsulfoxide (DMSO), dimethylformamide (DMF), benzene, toluene, xylene, Tetrahydrofuran and tetrahydrofuran (THF), wherein the dispersant is selected from the group consisting of sodium dodecylsulfonate, sodium dodecylbenzenesulfonate, sodium tetrapropylbenzenesulfonate tetrapropylene benzenesulphonate), and Triton X. The carbon nanotube dispersion solution is centrifuged at 10,000 rpm or more to remove carbon nanotube aggregates that have not been dispersed and purified.

The solvent in the second step may be any one or two of water, alcohol, acetone, dimethylsulfoxide (DMSO), dimethylformamide (DMF), benzene, toluene, xylene, pyridine, and tetrahydrofuran And the mixed solution in the third step is mixed with the graphene oxide dispersion solution in the range of 2 to 10% based on the total weight or the total volume of the carbon nanotube dispersion solution.

The substrate to be used in the fourth step may be formed of a nonconductive glass or plastic. The bonding of the mixed solution of the fourth step to the substrate may be performed by spray coating or spray coating of the mixed solution, And then transferred to a substrate. The fourth step further comprises washing with distilled water to remove the dispersant adhering to the surface, wherein the first drying in the fifth step is performed at a temperature of 20 to 150 ° C.

Preferably, the substrate containing the graphene oxide is used as the working electrode, the Ag / AgCl electrode is used as the reference electrode, the platinum plate is used as the reference electrode, Is used as a counter electrode, and a 0.05 to 0.2 M phosphate buffer solution (PBS) is used to impart water conductivity.

According to another aspect of the present invention, there is provided a method of fabricating a dye-sensitized solar cell, comprising combining a carbon nanotube and a graphene oxide mixed solution on a non-conductive substrate, Another technical feature is that it is used as an electrode.

Since the present invention does not use a toxic substance, it is eco-friendly and can be applied to a flexible plastic substrate by employing a low-temperature process.

In addition, since a low-cost nano-carbon electrode is formed on a nonconductive substrate in one layer, it is possible to reduce the material cost and simplify the manufacturing process, and achieve high performance similar to that of the existing platinum, thereby providing another effect that can be used as a catalyst electrode.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a conceptual view showing an electrode in which a conductive catalyst is attached to a conductive substrate coated with ITO or FTO.
FIG. 2 is a conceptual diagram showing a nano-carbon based integrated conductive electrode formed by mixing a carbon nanotube and a graphene oxide according to the present invention.
3 illustrates a cell structure for electrochemical reduction of graphene oxide according to the present invention.
FIG. 4 is a graph showing a transmittance curve of a SWNT conductive catalyst electrode coated on a glass substrate according to the present invention, a graph (b) of a photocurrent voltage applied to a solar cell, and an impedance curve (1 sun, .
5 is a graph showing (a) Raman spectra, (b) XPS spectra and (c) surface SEM images (sheet resistance 30 Ω / sq.) Of the SWNT conductive catalyst electrode coated on the glass substrate according to the present invention.
6 is a graph showing changes in sheet resistance according to the number of times of spray coating of a CNT dispersion solution for electrode coating according to the present invention.
7 is a graph showing the photocurrent-voltage curve of a dye-sensitized solar cell using a Pt counter electrode, which is vacuum-deposited on an ITO-coated PET substrate, and a SWNT and SWNT / GO composite electrode coated on a PET substrate according to the present invention as a counter electrode. * chemical reduction: when GO is reduced using hydrazine vapor. ** electrochemcial reduction: when GO is electrochemically reduced. (b) Scanning electron micrograph of electrode surface coated with SWNT / GO = 95/5 (v / v) dispersion solution.
FIG. 8 is an electrochemical reduction curve of (a) SWNT composite electrode coated on a PET plastic substrate according to the present invention, and a photocurrent-voltage curve of the dye-sensitized solar cell using the same as a counter electrode. Surface SEM photograph of SWNT / GO electrode according to GO content of SWNT / GO dispersion solution. (c) SWNT / GO = 98/2 (v / v), and (d) SWNT / GO = 85/15.
Figure 9 shows the physical and chemical properties of GO used in the manufacture of SWNT / GO composite electrodes. (a) Raman spectra, (b) XPS spectra, and (c) SiO 2 substrates.
FIG. 10 is a view showing a resistance change according to a bending degree of the electrode according to the present invention, and (b) a resistance variation according to a bending repeat number. FIG.

The present invention relates to a method of using a nanocarbon-based material as a counter electrode in a dye-sensitized solar cell and as a general electrochemical electrode by combining a nano-carbon-based material on a nonconductive glass or a flexible nonconductive plastic substrate. According to an electrode and a manufacturing method thereof, a main point is to manufacture an electrode capable of achieving high efficiency by coating a nano-carbon based material composed of a mixture of carbon nanotubes and graphene oxide on a substrate and treating the resultant at a low temperature.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a nano-carbon based integral type conductive electrode according to the present invention will be described with reference to the accompanying drawings.

2 is a conceptual diagram illustrating the structure of a nano-carbon based integrated conductive electrode according to the present invention.

As shown in the figure, a non-conductive glass substrate and a flexible plastic substrate 200 on which ITO or FTO is not coated can be used as a base substrate. A nano-carbon based material 100 in which carbon nanotubes and graphene oxides are mixed is coated on the upper surface of the substrate 200 to form an electrode. The unexplained reference numeral 300 is used for reduction of graphene oxide, which will be described later, by a low-temperature aqueous reduction process at 150 ° C or lower, thereby enabling the use of a flexible substrate 200 such as a plastic. Hereinafter, the present invention will be described in more detail.

Carbon nanotubes and graphene oxide

The single layer used in the present invention is a mixture of carbon nanotubes and graphene oxide (GO). First, carbon nanotubes have a structure called a graphene surface, which is wrapped in a tube shape. When a multi-walled graphene wall is formed, multi-walled carbon nanotubes and a single-layer graphene surface When it has walls, it is called single-walled carbon nanotubes (SWNTs). The carbon nanotubes used in the present invention may be single-walled carbon nanotubes (SWNTs), and any type of single-walled carbon nanotubes (SWNTs) may be used as long as they are in powder form. Also, graphene oxide can be made in any form as long as it is in powder form. In this description, single-walled carbon nanotubes were purchased from the market, and graphene oxide was optionally synthesized by Modified Hummer's method.

Manufacture of carbon nanotube dispersion solution

The carbon nanotube powder and the dispersant are mixed with a solvent to prepare a purified and dispersed solution of carbon nanotubes. The solvent used herein may be a mixture of any one or more of water, alcohol, acetone, methylsulfoxide (DMSO), dimethylformamide (DMF), benzene, toluene, xylene, pyridine and tetrahydrofuran . The dispersing agent may be selected from the group consisting of sodium dodecylsulfonate, sodium dodecylbenzenesulfonate, sodium tetrapropylene benzenesulphonate, Triton X Or a mixture of two or more of them may be used. Also, it is preferable that the carbon nanotube dispersion solution is centrifuged at 10,000 rpm or more to remove the metal catalyst and the aggregated carbon nanotube aggregates.

Preparation of graphene oxide dispersion solution

The graphene oxide powder is dispersed in a separate solvent to prepare a dispersion solution. The solvent may be used by mixing any one or more of water, alcohol, acetone, dimethylsulfoxide (DMSO), dimethylformamide (DMF), benzene, toluene, xylene, pyridine, tetrahydrofuran . It is also preferable to use ultrasound to perform the dispersion effectively. The dispersion during the ultrasonic treatment is more effective, and it usually takes about 1 to 2 hours to prepare such a dispersion solution.

Preparation of mixed solution of carbon nanotube and graphene oxide dispersion solution

The prepared carbon nanotube dispersion solution and the graphene oxide dispersion solution are mixed to prepare a mixed solution. The mixed solution may be mixed in an appropriate volume ratio or weight ratio, and the mixing ratio of the carbon / tube dispersion solution: graphene oxide dispersion solution may be mixed in the volume ratio or weight ratio of 85 to 98: 2 to 15. When 10% or more of the dispersion solution of graphene oxide is mixed. It was found that the graphene oxide in the form of a sheet interfered with the diffusion of the redox couple into the carbon nanotube electrode and the catalytic performance was rather deteriorated. When the amount was less than 2%, sufficient catalytic performance It can be said that this is not the case. The mixture is then mixed with a simple physical mixture and then stirred to ensure even mixing.

Board

The substrate to be used may be a non-conductive substrate, a glass substrate on which ITO or FTO is not coated, a flexible plastic substrate substrate, or the like. In particular, when a plastic substrate is used, there is an advantage that a flexible electrode can be manufactured.

The mixed solution is bonded to the surface of the nonconductive substrate to form an electrode

The above mixed solution is bonded to the nonconductive substrate in the form of a film having a thickness of several nanometers to several hundred nanometers. For this purpose, a spray coating method in which a dispersion solution is scattered and coated, or a method in which a dispersion solution is filtered on a filter paper and then transferred to a substrate can be used. After the mixed solution is bonded to the surface of the substrate as described above, the remaining dispersant becomes an impurity and is removed by washing with distilled water.

Electrode drying

In order to dry the mixed solution coated on the nonconductive substrate as described above, it is preferable to dry at a temperature of 20 to 150 ° C. Drying at a temperature lower than 20 ° C. takes too much time, and flowability is generated due to the flatness of the thin film of the dispersion solution. If the temperature is higher than 150 ° C., rapid drying may cause wrinkling of the film. There is a risk of deterioration.

Reduction of graphene oxide contained in the electrode

Since the plastic substrate is deformed at a high temperature of 150 ° C or more, it can not be subjected to a high temperature heat treatment for reduction of conventional graphene oxide, and chemical reductants such as hydrazine are strongly toxic, which can adversely affect both the human body and the environment. Therefore, in the present invention, electrochemical reduction is carried out in a water-based electrolyte by a low-temperature environmentally friendly reduction method. This prevents environmental pollution caused by the use of reducing agents such as conventional hydrazine, and does not require high temperature heat treatment. This water-based electrolyte reduction produces reduced graphene oxide (reduced GO, RGO) by removing the oxygen attached to the graphene oxide through an electrochemical method.

FIG. 3 shows the electrochemical reduction cell structure. As shown in FIG. 3, a substrate coated with a mixture of carbon nanotubes and graphene oxide is used as the working electrode 300, and Ag / AgCl (3M NaCl saturated) Was used as the reference electrode (500) and the platinum plate was used as the counter electrode (600). At this time, a 0.05-0.2 M phosphate buffer solution (PBS) can be used to impart conductivity of high purity water. The pH of the PBS is titrated with HCl and HNO3.

Drying of the reduced electrode

The drying is preferably carried out in the atmosphere at a temperature of 20 ° C to 150 ° C in an atmosphere of nitrogen, oxygen, or vacuum, and the dried electrode can be used as a translucent catalyst electrode of a dye-sensitized solar cell including an electrolyte.

As described above, the present invention basically uses a film made of a mixture of carbon nanotubes and graphene oxide, both of which have both conductivity and catalytic performance, on an inexpensive glass substrate on which ITO or FTO is not coated or on a plastic substrate having flexibility, .

The present invention has the advantage that a low-cost material can be manufactured at a low temperature by using a conductive electrode-integrated catalyst electrode which simultaneously performs the conductive function of ITO (Indium Tin Oxide) and FTO (fluorine doped tin oxide) and the catalytic function of platinum Furthermore, when applied to a flexible substrate, the lightweight dye-sensitized solar cell can be advantageously manufactured with an electrode that is stronger in bending than the ITO-coated plastic substrate and has excellent catalytic properties.

The electrochemical reduction method of graphene oxide of an electrode made by mixing carbon nanotube and graphene oxide is as follows: 1) In addition to using a non-toxic conductive aqueous solution, it can be used as a conventional reducing agent (hydrazine) And 2) it can be applied to a plastic substrate which can not be processed at a high temperature of 150 ° C or more

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Example

In the first step (preparation of carbon nanotube dispersion solution)

To disperse carbon nanotubes, 0.975 g of carbon nanotube powder (Single walled carbon nanotube) is added to 300 ml of a solvent (water) containing 1.0 wt% of a dispersant (sodium dodecylbenzenesulfonate) and sonicated for 2 hours. Centrifuge at 10,000 rpm for 30 minutes twice to collect only the supernatant with excellent dispersibility and use it as a carbon nanotube dispersion.

Second step (preparation of graphene oxide dispersion solution)

0.1 g of graphene oxide powder is added to 100 ml of distilled water and ultrasonicated for 1 hour.

Step 3 (Preparation of mixed solution of carbon nanotube and graphene oxide)

The prepared carbon nanotube dispersion solution and graphene oxide dispersion solution are mixed at a volume ratio of 95: 5 and dispersed to prepare a mixed solution.

Step 4 (mixed solution coating on substrate)

Nano-carbon electrodes are formed by coating on non-conductive substrates (glass and plastic) using spray coater equipment. At this time, the temperature of the substrate was set at 80 DEG C for uniform coating. The sheet resistance and transmittance of the electrode are adjusted by changing the number of coatings.

Step 5 (drying)

The coated nanocarbon electrode was dried in an oven at 120 ° C for 2 hours.

Step 6 (Reduction of electrode and drying of reduction electrode)

 Using a phosphate buffer solution of pH 2 as the electrolyte, it was reduced by electrochemical method at a scan rate of 500 mV / s and a scan range of 0 to -0.8 V, vacuum-dried at 45 ° C in a vacuum oven for 12 to 15 hours, .

Step 5 (used as electrode)

The electrode is used as a counter electrode of a dye-sensitized solar cell. At this time, the TiO 2 photoelectrode of the dye-sensitized solar cell was composed of an MK-2 organic dye (2-Cyano-3- [5 '' - (9- 3 '' ', 4-tetra-n-hexyl- [2,2', 5 ', 2 ", 5", 2' '] quaterthiophen-5-yl] acrylic acid as a light absorber And the electrolyte was cobalt (II / III) tris (2,2'-bipyridine) (Co (bpy) 32 + / 3 +) system as a redox pair. The electrolyte contains 0.165 M [Co (bpy) 3] (PF6) 2, 0.045 M [Co (bpy) 3] (PF6) 3, 0.1 M LiClO4 (Aldrich), and 0.2 M 4-tert- butylpyridine Based acetonitrile-based solution was used.

Hereinafter, results of experiments using a substrate prepared by reducing graphene oxide through the above process as a counter electrode of a dye-sensitized solar cell will be described.

4 is a graph showing the transmittance curves of a nano-carbon based integrated conductive catalyst electrode (referred to as "SWNT") coated on a glass substrate according to the present invention, the photocurrent voltage curve (b) Table 1 shows the values of the photoelectric properties of the dye-sensitized solar cell using the nano-carbon based integrated conductive catalyst electrode coated on the glass substrate as the counter electrode in accordance with the present invention. to be.

Counter electrode Jsc Voc FF efficiency Conductive catalyst material Transmittance (%) (mA / cm ² ) (V) (%) Reference specimen Pt / FTO-15? / Sq. - 11.47 0.775 0.707 6.29 Example SWNT-240? / Sq. 86.2 10.67 0.742 0.263 2.08 SWNT-120? / Sq. 80.8 11.64 0.725 0.349 2.94 SWNT-50? / Sq. 62.4 11.80 0.742 0.501 4.38 SWNT-30? / Sq. 41.6 11.27 0.725 0.641 5.24 SWNT-15? / Sq. 17.7 11.66 0.741 0.696 6.02

As shown in FIG. 3A, as the coating amount (loading amount) of the carbon nanotubes on a glass substrate having no conductive transparent electrode such as FTO or ITO increases, the transmittance decreases (FIG. 3A) When applied to a solar cell, the fill factor and efficiency of the solar cell are improved as the number of coatings (i.e., loading amount) of the SWNT electrode is increased (FIG. 3B, Table 1) It can be seen that the ohmic resistance corresponding to the crossed intercept decreases (FIG. 3c).

5 is a graph showing (a) Raman spectrum, (b) XPS spectra and (c) surface SEM photograph (sheet resistance 30 Ω / sq.) Of the SWNT conductive catalyst electrode according to the present invention.

As shown in the figure, the SWNT used in the present invention has excellent crystallographic properties as shown by the Raman and XPS results, and the surface of the SWNT electrode coated on the plastic substrate is well visible Able to know.

6 is a graph showing changes in sheet resistance according to the number of times of spray coating of the SWNT dispersion solution for electrode coating according to the present invention. As shown, when the SWNT electrode is manufactured using a spray coater, the sheet resistance decreases as the number of spray coatings of the SWNT dispersion solution increases. The sheet resistance of conductive transparent electrodes, such as ITO or FTO, is generally 15 Ω / sq. , The SWNT electrode according to the present invention also has a sheet resistance of 15 Ω / sq. , It can be seen that the use of SWNT electrode of 30 Ω / sq. Is reasonable considering the amount of material used as the number of coatings increases.

7 is a graph showing the photocurrent-voltage curve of the dye-sensitized solar cell using the Pt counter electrode, which is vacuum-deposited on the ITO-coated PET substrate, and the SWNT and SWNT / GO composite electrode coated on the PET substrate according to the present invention, to be. * chemical reduction: when GO is reduced using hydrazine vapor. ** electrochemcial reduction: when GO is electrochemically reduced. At this time, the mixed solution was applied using a dispersion solution having a volume ratio of SWNT: GO of 95: 5 (v / v) Fig. 5 is a photograph showing a surface scanning microscope photograph. Fig. Table 2 is a table summarizing the photoelectric property values of the dye-sensitized solar cell using SWNT and SWNT / GO conductive catalyst electrode applied as a counter electrode on a PET plastic substrate according to the present invention.

sample Counter electrode Jsc Voc FF efficiency Dispersion solution jet
Number of times Post treatment Transmittance
(%) (mA / cm ² ) (V) (%) Reference specimen sputter-Pt / ITO - - 47.8% 11.79 0.758 0.677 6.05 room
city
Yes SWNT 105 Vacuum drying
(45 DEG C) 43.6% 11.01 0.758 0.639 5.33 SWNT / GO
= 95/5 (v / v) 105 chemical red.
(N ₂ H ₄ vapor) 43.9% 11.67 0.758 0.413 3.66 SWNT / GO
= 95/5 (v / v) 105 electrochem. red.
(pH 5.0 PBS,
10 mV / s) 44.4% 11.40 0.758 0.699 6.04

As shown in the figure, when a counter electrode based on plastic (PET), SWNT-GO (SWNT: GO == 95: 5, (v / v)) is applied to a dye-sensitized solar cell, The chemical reduction using the hydrazine vapor revealed that the characteristics of the solar cell were deteriorated (the fill factor and the efficiency were decreased). In the post treatment method, the environmentally low toxicity Electrochemical reduction using chemical is the best. ** It also shows the same level of properties as the Pt thin film deposited by the sputter technique, and thus the electrochemically reduced SWNT-GO composite electrode is superior Electrochemical properties.

Next, FIG. 8 (a) shows an electrochemical reduction curve according to the GO content of the SWNT composite electrode (a) applied to the PET plastic substrate according to the present invention, and the photocurrent of the dye- - Voltage curves and photoelectric property values are shown in FIG. 8 (b) and Table 3. It can be seen from FIG. 8 (c, d) that the proportion of the GO having a two-dimensional structure increases as the GO content of the SWNT / GO dispersion solution increases.

sample Counter electrode Jsc Voc FF efficiency Dispersion solution ratio
(SWNT / GO) Post treatment (mA / cm ² ) (V) (%) room
city
Yes 100/0 Vacuum drying 11.01 0.758 0.639 5.33 98/2 EC-red. † 11.45 0.775 0.661 5.87 95/5 EC-red. † 11.40 0.758 0.699 6.04 85/15 EC-red. † 11.07 0.775 0.592 5.08

EC-red. †: pH 2.0 buffer solution, scan rate: 500 mV / s

As shown in the figure, when a plastic (PET) based SWNT / GO counter electrode is applied to a dye-sensitized solar cell, the optimal mixing ratio (95: 5) of SWNT / GO is known by using an excellent electrochemical reduction method When the GO of the WNT / GO electrode is reduced to RGO, the electron transfer is enhanced by 1) the junction area between the SWNT electrodes is improved, and 2) the RNO 3 has more defect sites than the SWNTs. Could know. However, when the GO content was too high, it was found that the sheet type GO interfered with the diffusion of the redox pair into the SWNT electrode, and the catalyst performance was rather lowered (SWNT: GO = 70: 30). Therefore, it was found that the amount of graphene oxide to be added should be less than 15%.

The physical and chemical properties of GO used in SWNT / GO composite electrode fabrication are shown in FIG. As shown in the figure, the GO used in the preparation of the SWNT-GO composite electrode used in the present invention has a large number of crystallographic defects and oxygen functional groups, which can be confirmed by Raman and XPS results. As shown in the SEM photograph, And a grains having a size of 1 to 2 탆 (GO nanosheet).

FIG. 10 is a graph showing a change in resistance according to the degree of bending (a) and a change in resistance according to the number of bending cycles (b) of the electrode according to the present invention. As shown in the figure, SWNT / PET (polyethyleneterephthalate) electrode exhibits excellent characteristics with no significant change in resistance according to the bending degree and the resistance according to the number of bending repetitions, which is applied to a flexible plastic substrate And it is possible to form a flexible counter electrode.

According to the above experimental results, the nano-carbon based integrated conductive catalytic electrode made by mixing the carbon nanotube and the graphene oxide according to the present invention can be applied to non-conductive glass, plastic, etc., and exhibits excellent catalytic electrode performance. Type solar cell or an electrode of another chemical cell.

Claims (14)

A first step of dispersing the carbon nanotube powder in a first solvent to prepare a dispersion solution;
A second step of dispersing the graphene oxide powder in a second solvent to prepare a dispersion solution;
A third step of mixing the dispersion solutions formed in the first and second steps to prepare a mixed solution;
A fourth step of bonding the mixed solution of the third step to the surface of the nonconductive substrate;
A fifth step of first drying the substrate after the fourth step;
A sixth step of reducing the graphene oxide contained in the conductive substrate after the fifth step to electrochemical reduction using an aqueous electrolyte;
And a second step of drying the substrate after the sixth step. The nanocarbon-based film formed by mixing the carbon nanotubes and the graphene oxide on the nonconductive substrate is used as a catalyst electrode by bonding the nanocarbon- Wherein the carbon nanotubes are mixed with graphene oxide. 2. The method according to claim 1,
The dispersant is further mixed and the first solvent is any one or both of water, alcohol, acetone, dimethylsulfoxide (DMSO), dimethylformamide (DMF), benzene, toluene, xylene, pyridine and tetrahydrofuran Wherein the carbon nanotubes and the graphene oxides are mixed with each other to produce a nanocarbon-based integrated conductive catalyst electrode. 3. The method according to claim 2,
Sodium dodecylbenzenesulfonate, sodium tetrapropylene benzenesulphonate, and Triton X are used in combination, and the dispersion of carbon nanotubes Wherein the solution is purified by removing agglomerates of carbon nanotubes that have not been dispersed by centrifugation at 10,000 rpm or more. The method of manufacturing a nanocarbon-based integrated conductive catalyst electrode comprising a mixture of carbon nanotubes and graphene oxide . The method according to claim 1,
Characterized in that any one or two or more of water, alcohol, acetone, dimethylsulfoxide (DMSO), dimethylformamide (DMF), benzene, toluene, xylene, pyridine and tetrahydrofuran (EN) METHOD FOR MANUFACTURING NANOCARBON - BASED INTEGRATED CONDUCTIVE CATALYST electrode mixed with carbon nanotube and graphene oxide. 2. The method according to claim 1,
Wherein the graphene oxide dispersion solution is mixed in a range of 2 to 15% based on the total weight or the total volume of the carbon nanotube dispersion solution. The nano-carbon based integrated conductive catalyst electrode ≪ / RTI > The method according to any one of claims 1 to 5, wherein the substrate used in the fourth step is made of a nonconductive glass or plastic. The nano carbon mixed with the graphene oxide Based integrated catalytic electrode. [7] The method according to claim 6, wherein bonding the mixed solution of the fourth step to the substrate comprises spray coating the mixed solution by spraying or spraying the mixed solution onto the filter paper, Wherein the carbon nanotubes are mixed with graphene oxide. [7] The method of claim 7, further comprising, after the fourth step, washing with distilled water to remove the dispersant attached to the surface. The nano-carbon based integrated conductive catalyst mixed with the graphene oxide Gt; The method according to claim 7, wherein the first drying of the fifth step is performed at a temperature of 20 to 150 ° C. The method according to claim 9, wherein the reduction of the sixth step is carried out electrochemically in the aqueous electrolyte. The method of claim 1, wherein the carbon nanotubes and the graphene oxide are mixed. The electrochemical reduction method according to claim 10, wherein the electrochemical reduction is performed using a substrate containing the graphene oxide as a working electrode and a 0.05 to 0.2 M phosphate buffer solution (PBS) to provide conductivity of the aqueous electrolyte. Wherein the carbon nanotubes and the graphene oxide are mixed with each other. 12. The method of claim 11, wherein the second drying of the seventh step is performed at a temperature of 20 to 150 DEG C in the atmosphere, nitrogen, oxygen atmosphere, or vacuum. Based integrated catalytic electrode. A substrate according to any one of claims 1 to 5, wherein the substrate formed by reducing the graphene oxide is used as a catalyst electrode, and a mixed solution of carbon nanotubes and graphene oxide is bonded to a nonconductive substrate An integrated conductive catalytic electrode based on nano-carbon with carbon nanotube and graphene oxide mixed. The nano-carbon based integrated conductive catalyst electrode according to claim 13, wherein the catalyst electrode is used as a counter electrode of the dye-sensitized solar cell.

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