KR101406427B1 - Conductive polymer-carbon composite electrode for dye sensitized solar cell having catalytic activity and electrical conductivity and dye sensitized solar cell using the same and method for manufacturing thereof - Google Patents

Abstract

The present invention relates to a conductive polymer-carbon compound electrode for a dye-sensitized solar cell having excellent catalytic activity and electrical conductivity capable of being used as a catalytic electrode of a dye-sensitized solar cell, a dye-sensitized solar cell using the same, and a manufacturing method thereof. An embodiment of the present invention provides a conductive polymer-carbon compound electrode for a dye-sensitized solar cell which includes a porous carbon-material aggregating agent and conductive polymers wherein part or all of the conductive polymers are placed in pores of the carbon-material aggregating agent, a dye-sensitized solar cell using the same, and a manufacturing method thereof. According to the present invention, provided are the conductive polymer-carbon compound electrode for a dye-sensitized solar cell which has excellent electrical conductivity and catalytic activity compared to the existing carbon electrode, is able to effectively reduce the charge moving resistance inside the electrode and on the interface between electrolyte and a counter electrode, and accordingly is expected to improve efficiency, the dye-sensitized solar cell using the same, and the manufacturing method thereof.

Description

TECHNICAL FIELD [0001] The present invention relates to a conductive polymer-carbon composite electrode for a dye-sensitized solar cell having excellent catalytic activity and electrical conductivity, a dye-sensitized solar cell using the same, and a method for producing the same. BACKGROUND ART AND DYE SENSITIZED SOLAR CELL USING THE SAME AND METHOD FOR MANUFACTURING THEREOF}

TECHNICAL FIELD The present invention relates to a conductive polymer-carbon composite electrode for a dye-sensitized solar cell having excellent catalytic activity and electrical conductivity, a dye-sensitized solar cell using the same, and more particularly, The present invention relates to a conductive polymer-carbon composite electrode for a dye-sensitized solar cell having excellent catalytic activity and electrical conductivity that can be utilized as an electrode, a dye-sensitized solar cell using the same, and a method of manufacturing the same.

Recently, serious environmental pollution problem is becoming more important for next generation clean energy development due to depletion of fossil energy. As a result, solar energy is expected to be an energy source that can solve future energy problems due to its infinite amount, semi-permanent life span and pollution-free advantages.

In order to utilize such solar energy, development and research of solar cells are actively being carried out. Such solar cells can be classified into first generation crystalline silicon solar cells, second generation thin film solar cells, and third generation next generation solar cells. Among them, the dye-sensitized solar cell, which is one of the third-generation solar cells, differs from the silicon solar cell, which is problematic due to the limitation of the cost of the silicon raw material and the installation site. In contrast to the amorphous silicon solar cell which is one of the second- In addition to its energy conversion efficiency, it has attracted a great deal of attention due to its low manufacturing cost, which is one fifth of that of silicon solar cells. In addition, the dye-sensitized solar cell is based on the use of a transparent conductive glass substrate, and can use dyes and electrolytes having various colors, thus making it possible to manufacture modules of various colors, and thus can be applied to interior / exterior materials of a building .

The dye-sensitized solar cell having the above-described characteristics comprises a conductive substrate on which a transparent conductive film is formed, an oxide semiconductor electrode (hereinafter also referred to as a "photoelectrode") on which the dye formed on the transparent conductive film is adsorbed, (Hereinafter also referred to as a "counter electrode") formed on the transparent conductive film, and an electrolyte having an oxidation-reduction pair is provided between the photoelectrode and the counter electrode.

When such a dye-sensitized solar cell is irradiated with light, the dye absorbing light generates an electron-hole pair, and the electrons are injected into the conduction band of the oxide semiconductor. The injected electrons are transferred to the transparent conductive film through the oxide semiconductor and generate electric current while moving through the external circuit connecting the photoelectrode and the counter electrode. The holes produced in the dye are reduced again by receiving electrons from the electrolyte having the redox pair, and the driving of the dye-sensitized solar cell is completed through this process. Here, the counter electrode serves to provide the electrons transferred through the external circuit to the electrolyte so that the redox reaction of the ions in the electrolyte can take place.

The catalytic electrode should transfer the electrons moved through the external circuit to the electrolyte at high speed so that the redox reaction of the electrolyte can be smoothly performed. At this time, the catalyst electrode must have a low charge transfer resistance at the interface with the electrolyte so that electrons can be smoothly transferred. Therefore, the catalyst electrode must have high catalytic activity, electric conductivity, and large surface area.

In general, platinum has been used as a catalyst electrode exhibiting the most excellent properties in a dye-sensitized solar cell. However, platinum is expensive and has a problem of low long-term stability, which is oxidized to form a complex when prolonged exposure to an iodine-based electrolyte, which is mainly used as an electrolytic material, is problematic. In addition, when a platinum catalyst electrode is manufactured using a vacuum deposition method such as sputtering, there is a disadvantage that a heat treatment step is carried out after a high temperature at 400 ° C. In recent years, studies have been conducted to apply a carbon material as a catalyst electrode have.

Carbon materials have excellent catalytic activity, low cost, and excellent long-term stability in iodine-based electrolytes. In addition, it can be used in a roll-to-roll continuous process using various types of flexible substrates since a solution process based low temperature process is possible.

In general, a carbon single electrode is manufactured by using a doctor blade method or a screen printing method using a carbon paste containing a binder and a surfactant. However, the carbon single electrode thus formed has a disadvantage in that the binder of the organic or inorganic material decreases the electric conductivity and the surface area, thereby deteriorating the catalytic properties, and accompanied by a heat treatment at a high temperature of 200 to 450 DEG C for removing impurities However, such a post-high temperature heat treatment process has a problem in that it is not suitable for a continuous roll-to-roll process using a flexible substrate. In addition, since the carbon single material has a relatively low catalytic activity as compared with platinum, it is required to increase the number of catalytic active sites by increasing the surface area of the electrode in order to obtain catalytic properties similar to platinum. To this end, the carbon single electrode has a thick thickness exceeding 15 탆, which increases the total internal resistance of the solar cell, thereby deteriorating the cell driving property.

The present invention relates to a conductive polymer-carbon composite electrode for a dye-sensitized solar cell having excellent catalytic activity and electrical conductivity so as to provide a smooth electron to an electrolyte having a redox pair, a dye-sensitized solar cell using the same, .

An embodiment of the present invention provides a conductive polymer-carbon composite electrode for a dye-sensitized solar cell comprising a carbon material aggregate having pores and a conductive polymer, wherein all or a part of the conductive polymer is located in pores of the aggregate of carbon material do.

Another embodiment of the present invention is a method for producing a semiconductor device, comprising: dispersing a conductive polymer in a first solvent to obtain a first solution; Dispersing a carbon material in a second solvent to obtain a second solution; Mixing the first solution and the second solution to obtain a composite solution in which the carbon material and the conductive polymer are dispersed; And thermally treating the complex solution at 100 to 150 ° C. to obtain a composite electrode. The present invention also provides a method for manufacturing a conductive polymer-carbon composite electrode for a dye-sensitized solar cell.

Another embodiment of the present invention is a liquid crystal display comprising: a first substrate; An oxide semiconductor electrode formed on the first substrate on which dye is adsorbed; A second substrate facing the oxide semiconductor electrode; A conductive polymer-carbon composite electrode formed on the second substrate; And an electrolyte disposed between the oxide semiconductor electrode and the conductive polymer-carbon composite electrode, wherein the conductive polymer-carbon composite electrode includes a carbon material and a conductive polymer, and the carbon material has a porous structure having pores And the conductive polymer is provided in the pores. The present invention also provides a dye-sensitized solar cell.

Yet another embodiment of the present invention is a method of manufacturing a semiconductor device, comprising: preparing a first substrate; Forming an oxide semiconductor electrode on the first substrate; Adsorbing a dye on the oxide semiconductor electrode; Preparing a second substrate; Dispersing a conductive polymer in a first solvent to obtain a first solution; Dispersing a carbon material in a second solvent to obtain a second solution; Mixing the first solution and the second solution to obtain a composite solution in which the carbon material and the conductive polymer are dispersed; Applying the composite solution to the second substrate; Forming a conductive polymer-carbon composite electrode by heat-treating the composite solution at 100 to 150 ° C; And injecting an electrolyte between the first substrate and the second substrate after positioning the first substrate and the second substrate so as to oppose each other, and then injecting an electrolyte between the first substrate and the second substrate.

According to the present invention, it is possible to effectively reduce the charge transfer resistance inside the electrode and the charge transfer resistance at the interface between the electrolyte and the counter electrode, thereby achieving an increase in efficiency. A conductive polymer-carbon composite electrode for a dye-sensitized solar cell, a dye-sensitized solar cell using the same, and a method of manufacturing the same.

In addition, since the polymer-carbon composite electrode of the present invention can perform not only the catalytic activity but also the role of charge collection, it can be applied to a substrate on which a transparent conductive film is not formed and can be manufactured at a low cost, So that it is applicable to a continuous roll-to-roll process using a flexible substrate.

1 is a schematic view showing an example of a dye-sensitized solar cell.
FIG. 2 is a photograph of a catalyst electrode of a dye-sensitized solar cell manufactured according to an embodiment of the present invention by scanning electron microscopy (SEM), wherein (a) is 5P / CB, (b) c) is 17P / CB, and (d) is 20P / CB.
3 is a schematic view showing the structure of a symmetric cell for evaluating the catalytic activity characteristics.
4 is a schematic diagram showing an equivalent circuit model of a symmetric cell.
5 is a Nyquist plot showing the results of electrochemical impedance measurement of a dye-sensitized solar cell fabricated according to an embodiment of the present invention. FIG. 5 (a) is a graph showing the Nyquist plot of PEDOT: PSS / carbon black composite electrode (B) is the result of enlarging the high-frequency region of (a).
6 is a Nyquist plot showing the results of electrochemical impedance measurement of a dye-sensitized solar cell fabricated according to an embodiment of the present invention, wherein (a) shows the catalytic activity characteristics of a PEDOT: PSS / (B) is a result of enlarging the high-frequency region of (a).
7 is a graph of current density-voltage of a dye-sensitized solar cell fabricated according to an embodiment of the present invention.

1 is a schematic view showing an example of a dye-sensitized solar cell. Hereinafter, the present invention will be described with reference to Fig. FIG. 1 is an illustration for illustrating the present invention, but does not limit the scope of the present invention.

1, a dye-sensitized solar cell generally includes a first substrate 1 on which a transparent conductive film 2 having an oxide semiconductor electrode 3 on which a dye 4 is adsorbed, A second substrate 6 on which a catalyst electrode 5 positioned opposite to the first substrate 6 is coupled and an electrolyte 7 having an oxidation-reduction pair is interposed between the first substrate and the second substrate and the electrolyte 7 is sealed And a sealing material 8 for sealing.

As the electrolyte, an iodide (3I ^- ) / tri-iodide (I ₃ ^- ) redox pair is usually used. In this electrolyte, electrons are moved from the catalyst electrode 5, and a reduction reaction of tri-iodide (I ₃ ^- ) ions is caused by the electrons, and an iodide (3I ^- ) ion Will again supply the dye 4 with electrons. That is, since the electron transfer to the catalyst electrode electrolyte must be performed smoothly, the catalyst electrode is required to have a low charge transfer resistance at the interface with the electrolyte. For this purpose, high catalytic activity, large surface area and excellent electrical conductivity But should have excellent long-term stability in the electrolyte.

For this purpose, the present invention comprises a carbon material aggregate having pores and a conductive polymer, which is preferably applicable to a catalyst electrode among the constituent elements of the solar cell, wherein all or a part of the conductive polymer is aggregated A conductive polymer-carbon composite electrode for a dye-sensitized solar cell is provided in a pore.

In general, carbon materials have an advantage of having excellent catalytic activity, low cost, and long-term stability in iodine-based electrolytes. In addition, it can be used in a roll-to-roll continuous process using various types of flexible substrates since a solution process based low temperature process is possible. However, when such a carbon material is used alone as a carbon single electrode, the catalyst characteristics are deteriorated and it is difficult to apply it to a continuous roll-to-roll process by a post-high temperature heat treatment process. In addition, since it has relatively low catalytic activity as compared with platinum, it has to have a thick thickness in order to improve it, but it has disadvantages of decreasing the cell driving property by increasing the total internal resistance of the solar cell.

However, the conductive polymer-carbon composite electrode provided by the present invention can provide an electron transfer path between the carbon particles due to the high electrical conductivity (0.1 SIMILAR 10 S / cm) of the conductive polymer, thereby securing excellent electrical conductivity, It ensures the long-term durability by suppressing the separation of carbon particles through the effect of increasing the bonding force between particles. In addition, electrochemical stability of iodide (3I ^- ) and tri-iodide (I ₃ ^- ) can be obtained, and it is possible to have excellent long-term stability in iodine-based electrolyte, There are advantages. In addition, since the conductive polymer also has catalytic activity, it provides additional catalytic activity points to increase the contact area at the electrolyte / catalyst electrode interface, thereby lowering the charge transfer resistance, and the ionization (3I ^- ) and triiodide ₃ ^- ) can be improved.

In the present invention, the kind of the carbon material and the conductive polymer constituting the aggregate of the carbon material is not particularly limited. However, in order to obtain the desired effect, the carbon material may be selected from the group consisting of graphite, graphene, carbon nanofiber, carbon nanotube and carbon black Poly (styrene sulfonate) (PEDOT: PSS) and poly (styrenesulfone) as the conductive polymer and at least one selected from the group consisting of polyaniline, polypyrrole, poly (3,4-ethylenedioxythiophene) (PEDOT), which is used in the present invention.

On the other hand, it is preferable that the average size of each carbon material constituting the aggregate of the carbon material is in the range of 20 to 90 nm. When the carbon material is less than 20 nm, it is difficult to form the primary aggregate, , And when it is more than 90 nm, the surface area per unit volume decreases as the particle size increases, and the catalyst properties deteriorate, and the connectivity between the carbon particles decreases and the electrical conductivity decreases. In addition, when the average size of the carbon material exceeds 90 nm, the electrical conductivity is reduced by 50% or more and the surface area is reduced by 70% or more as compared with the case of having an average size of 20 nm, It is difficult to ensure conductivity and catalytic activity. Therefore, it is preferable that the carbon material has an average size of 20 to 90 nm.

Also, the conductive polymer-carbon composite electrode of the present invention preferably contains the conductive polymer in an amount of 1 to 19% by weight. If the content of the conductive polymer is 1% by weight, the proportion of the conductive polymer may be low and the conductivity of the carbon catalyst electrode may be deteriorated. If the content of the conductive polymer exceeds 19% by weight, Thereby reducing the surface area of the composite electrode, thereby deteriorating the catalyst characteristics. Therefore, the content of the conductive polymer is preferably in the range of 1 to 19% by weight. The content of the conductive polymer is more preferably in the range of 5 to 19% by weight, and still more preferably in the range of 9 to 19%.

The conductive polymer-carbon composite electrode for a dye-sensitized solar cell of the present invention, which is provided as described above, has excellent electric conductivity and catalytic activity as compared with a conventional carbon single electrode, and has a charge transfer resistance inside the electrode and an electrolyte / It is possible to effectively reduce the charge transfer resistance in the light emitting device, thereby increasing the efficiency. In addition, the conductive polymer-carbon composite electrode provided by the present invention is advantageous in that it is considerably inexpensive and has a similar efficiency as compared with the conventional platinum catalyst electrode.

Hereinafter, one embodiment of the method for producing the conductive polymer-carbon composite electrode of the present invention will be described.

First, after a conductive polymer and a carbon material are prepared, the conductive polymer is dispersed in a first solvent to obtain a first solution, and the carbon material is dispersed in a second solvent to obtain a second solution. As the first solvent, it is possible to use isopropanol, ethylenecycloal and the like, and the conductive polymer may be water (e.g., poly (3,4-ethylenedioxythiophene) Water may be used if it has a structure capable of dissolving in water. As the second solvent, it is preferable to use at least one alcohol selected from the group consisting of isopropanol, methanol and ethanol to improve the dispersion of the carbon material. The first solution and the second solution may be prepared by an ultrasonic method or a magnetic stirring method.

The first solution and the second solution obtained as described above are mixed to obtain a composite solution in which the carbon material and the conductive polymer are dispersed. The preparation of the complex solution may also be performed by ultrasonic or magnetic stirring.

Thereafter, the complex solution is heat-treated at 100 to 150 ° C to produce a composite electrode. The solvent can be evaporated through the heat treatment, and the arrangement of the composite electrodes can be made more compact. Also, it can be applied without difficulty to the continuous process of roll-to-roll through the heat treatment at a low temperature as described above. However, when the temperature is lower than 100 ° C, the solvent or water may not evaporate well, resulting in poor film characteristics. When the temperature is higher than 150 ° C, oxygen or water may be combined with the conductive polymer to form irreversible There may be a problem that conductivity changes due to a change. Therefore, the heat treatment temperature is preferably in the range of 100 to 150 ° C.

After the heat treatment, the composite electrode may be further treated with an acid to improve electrical conductivity. For example, when the conductive polymer is PEDOT: PSS, an anion having a negative charge in PEDOT: PSS in which a positive charge PEDOT and a negative charge PSS are ionically bonded through the acid treatment replaces the PSS, . The acid treatment is not particularly limited as long as it is a substance capable of achieving the above effect. For example, a solution in which hydrochloric acid and methanol are mixed can be used.

And the heat treatment of the composite electrode after the acid treatment. Through the heat treatment, the acid treatment solution can be evaporated in a short time and the efficiency can be improved. If the heat treatment temperature is lower than 100 ° C, the evaporation time of the acid treatment solution may become excessively long and the productivity may be deteriorated. When the heat treatment temperature exceeds 150 ° C, the conductive polymer So that the conductivity may be reduced. Therefore, the heat treatment temperature is preferably in the range of 100 to 150 ° C.

Hereinafter, an embodiment of a dye-sensitized solar cell using the conductive polymer-carbon composite electrode of the present invention will be described.

According to one embodiment of the present invention, there is provided a plasma display panel comprising: a first substrate; An oxide semiconductor electrode formed on the first substrate on which dye is adsorbed; A second substrate facing the oxide semiconductor electrode; A conductive polymer-carbon composite electrode formed on the second substrate; And an electrolyte disposed between the oxide semiconductor electrode and the conductive polymer-carbon composite electrode, wherein the conductive polymer-carbon composite electrode includes a carbon material and a conductive polymer, and the carbon material has a porous structure having pores And the conductive polymer is provided in the pores. The present invention also provides a dye-sensitized solar cell.

At this time, the conductive polymer-carbon composite electrode preferably has a thickness of 1 to 15 탆. If the thickness of the conductive polymer-carbon composite electrode is less than 1 탆, a sufficient surface area can not be secured and it may be difficult to obtain the desired effect of the catalyst electrode. If the thickness exceeds 15 탆, Thereby increasing the overall internal resistance of the cell. Therefore, it is preferable that the conductive polymer-carbon composite electrode has a thickness of 1 to 15 탆.

Meanwhile, one of a glass substrate, a polymer film substrate, and a metal substrate may be used as the first substrate or the second substrate. However, in the case where a metal substrate is used for both the first substrate and the second substrate, since light can not penetrate into the solar cell, it is possible to apply a metal substrate only to the substrate on the side where no light is incident on the first substrate or the second substrate It is possible. That is, when the substrate on one side is a metal substrate, the substrate on the other side should not use a metal substrate. In addition, in order to apply the first substrate and the second substrate to the roll-to-roll continuous process, a flexible polymer film substrate or a metal substrate is preferable.

It is also required that a transparent conductive film be formed between the first substrate and the oxide semiconductor electrode. This is because it is difficult for electrons transferred from the oxide semiconductor layer to move to the catalyst electrode formed on the second substrate if the first substrate does not have conductivity. Therefore, it is preferable that a transparent conductive film is formed on a glass substrate, a polymer film substrate, or a metal substrate that can be used as a substrate. However, in the case of a metal substrate, since it has conductivity, it can be used without a transparent conductive film.

As the transparent conductive film, any one widely used in the related art can be used. For example, one kind selected from the group consisting of ZnO, AZO, IZO, GZO, FTO and ITO can be used. FTO and ITO have excellent conductivity, transparency and heat resistance, and ZnO and AZO are advantageous in terms of cost.

On the other hand, the transparent conductive film as described above may be formed between the second substrate and the conductive polymer-carbon composite electrode. However, the composite electrode provided by the present invention is formed on the second substrate, and the composite electrode can perform not only the catalytic activity but also the charge collection, so that the composite electrode can be applied to the substrate on which the transparent conductive film is not formed.

The oxide semiconductor electrode may be any of those widely used in the art, for example, one of TiO ₂ , SnO ₂ and ZnO. The oxide semiconductor electrode preferably has a thickness of 3 to 20 占 퐉. When the oxide semiconductor electrode is less than 3 占 퐉, the oxide semiconductor can not absorb a sufficient amount of dye necessary for driving the battery, If it is more than 20 탆, the dye is excessively adsorbed to increase the amount of dye, but the efficiency of the solar cell hardly increases, resulting in an increase in cost. Therefore, the thickness of the oxide semiconductor electrode is preferably in the range of 3 to 20 占 퐉.

The dyes may also be all those widely used in the art, for example, ruthenium-based dyes or organic dyes.

Hereinafter, one embodiment of a method for producing a dye-sensitized solar cell of the present invention will be described.

First, a first substrate is prepared for manufacturing a photo electrode. At this time, it is preferable to form a transparent conductive film on the first substrate. Thereafter, an oxide semiconductor electrode is formed on the first substrate. The oxide semiconductor electrode may be formed by coating an oxide semiconductor on the first substrate using a method commonly used in the art, followed by heat treatment at 100 to 550 ° C. When the temperature of the heat treatment is less than 100 ° C, it is difficult to effectively remove the organic binder used in the formation of the oxide semiconductor. When the temperature exceeds 550 ° C, the energy structure changes as the phase of the oxide semiconductor changes, There is a possibility that the resistance to move to < RTI ID = 0.0 > In addition, due to the phase change of the oxide semiconductor and the drastic increase of grain size of the grains, dye adsorption may not be easily performed. Therefore, the heat treatment temperature is preferably in the range of 100 to 550 ° C. Thereafter, the dye is adsorbed on the oxide semiconductor electrode by a method commonly used in the art.

In order to manufacture the counter electrode separately from the photoelectrode fabrication, a second substrate is first prepared. At the time of preparing the second substrate, a transparent conductive film may be formed on the second substrate. The first solution is obtained by dispersing a conductive polymer in a first solvent prepared in advance, a carbon material is dispersed in a second solvent to obtain a second solution, and then the carbon material and the conductive polymer are dispersed, The second solution is mixed to obtain a composite solution. Thereafter, the composite solution is applied onto the second substrate prepared above. At this time, any method commonly used in the related art can be used as a coating method, and for example, one of spray coating, drop coating, spin coating, inkjet printing, brush coating and dip coating can be used. Thereafter, the second substrate coated with the complex solution is heat-treated at 100 to 150 ° C to form a conductive polymer-carbon composite electrode on the second substrate.

Then, the dye-sensitized solar cell can be manufactured by positioning the first substrate and the second substrate so as to face each other, and then injecting an electrolyte between the first substrate and the second substrate.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the following examples are only illustrative of the present invention in more detail and do not limit the scope of the present invention.

(Example)

Photo electrode manufacturing

A TiO ₂ paste containing TiO ₂ nanoparticles having a diameter of about 20 nm and an organic binder was coated on a glass substrate coated with an FTO transparent conductive film by screen printing and then sintered at 120 ° C. to form a TiO ₂ Thereby forming an oxide semiconductor thin film. This process was repeated three times, and a substrate having a TiO ₂ oxide semiconductor thin film having a thickness of about 12 μm was formed through sintering at 500 ° C. The substrate on which the TiO ₂ oxide semiconductor thin film was formed was immersed in a solution of ruthenium dye (di-tetrabutylammonium cis-bis (isothiocyanato) bis (2,2'-bipyridyl-4,4'-dicarboxylato) ruthenium And the dye was adsorbed on the TiO ₂ oxide semiconductor thin film to complete the manufacture of the photoelectrode.

Relative electrode manufacturing

First, 1 wt% of PEDOT: PSS conductive polymer was dispersed in water to obtain a first solution, and carbon black having a diameter of about 20 nm was dispersed in ethanol to obtain a second solution. The amounts of the first solution and the second solution were controlled and mixed, and the carbon black was dispersed for about 1 hour by using ultrasonic waves to obtain 5 wt%, 9 wt%, 13 wt%, 17 wt%, and 20 wt% (Hereinafter referred to as 5P / CB, 9P / CB, 13P / CB, 17P / CB and 20P / CB depending on the composition ratio of PEDOT: PSS) . The PEDOT: PSS / carbon black composite solution was coated on the FTO glass substrate having a hydrophilic surface by UV treatment by spin coating. Subsequently, the substrate coated with the PEDOT: PSS / carbon black composite solution was heat-treated at 100 ° C in a vacuum oven for 1 hour, and then acid-treated with an acid solution having a volume ratio of hydrochloric acid: methanol of 1: 1 for 1 hour. The substrate coated with the acid-treated PEDOT: PSS / carbon black composite was again subjected to heat treatment in a 100 ° C vacuum oven for 1 hour to complete the preparation of a counter electrode (catalyst electrode).

Dye-sensitized solar cell manufacturing

A polymer resin having a thickness of 60 탆 was placed on the photoelectrode prepared as described above, and the counter electrode was opposed to the photoelectrode and then heat was applied to bond the two electrodes. Then, a liquid type iodine electrolyte was injected to prepare a dye-sensitized solar cell.

2 (a) and 2 (b) show photographs of the catalyst electrodes of 5P / CB, 9P / CB, 17P / CB and 20P / CB observed by a scanning electron microscope (SEM) ), (c) and (d).

As shown in FIG. 2, it can be seen that each catalyst electrode has a structure in which carbon black particles are aggregated with each other, and PEDOT: PSS is located in the pores of the carbon black. When 5 to 17 wt% of PEDOT: PSS is added, the composite electrode has a porous structure having pores, but when 20 wt% of PEDOT: PSS is added, most of the pores of the carbon black are clogged have. This shows that the excess PEDOT: PSS addition blocks the pores of the carbon black, thereby reducing the surface area of the composite electrode and also the catalyst properties.

Manufacture of symmetric cell for characterization of catalytic activity

In order to evaluate the catalytic activity, a symmetric cell having a structure as shown in FIG. 3 was prepared using the above-described method. The symmetric cell has a structure in which counter electrodes where a PEDOT: PSS / carbon black composite electrode 11 is formed on a substrate 10 on which a transparent conductive film is formed are opposed to each other and an electrolyte 12 is present therebetween. After measuring the electrochemical impedance using this symmetric cell, the results were analyzed using the equivalent circuit model as shown in FIG. The equivalent circuit model is based on the surface resistance (R _s ) of the substrate, the electron transfer resistance (R _trns ) and capacitance (C _trap ) inside the composite electrode, the charge transfer resistance (Rct) at the interface between the electrolyte and the composite electrode, and the electric double layer capacitance C _dl ), and an impedance (Z _n ) due to ion diffusion in the electrolyte.

The electrochemical impedance measurement results as described above are shown in FIG. 5 (a) shows the catalytic activity characteristics of the PEDOT: PSS / carbon black composite electrode according to the composition ratio of PEDOT: PSS, and FIG. 5 (b) shows the result of enlarging the high frequency region of (a). As shown in FIG. 5, in the case of a carbon single electrode to which PEDOT: PSS is not added, it can be seen that the electric conductivity is very low as compared with a composite electrode in which PEDOT: PSS is added in an amount of 5 to 20 wt%. In addition, as the content of PEDOT: PSS increases, the number of transport paths of electrons increases, so that R _trns decreases as the electric conductivity increases. In addition, it can be seen that R _ct is decreased due to an increase in the number of catalytic active sites in the composite electrode due to the additional catalytic activity of PEDOT: PSS. However, in the case of 20P / CB in which excess PEDOT: PSS is added, it can be seen that R _ct is increased because PEDOT: PSS blocks the pores of carbon black and reduces the contact area with the electrolyte. This shows that the composite electrode with 17 wt% PEDOT: PSS added exhibits the lowest charge transfer resistance at the interface and exhibits excellent catalytic properties.

In order to observe the catalyst characteristics according to the thickness, a PEDOT: PSS / carbon black composite electrode containing 17 wt% of PEDOT: PSS was prepared by using the above-mentioned method. In this case, A symmetric cell having thicknesses of 1 탆, 2.5 탆, 3.5 탆 and 4.5 탆, respectively, was prepared. The electrochemical impedance was measured using this symmetric cell, and the results are shown in Fig.

As shown in FIG. 6, it can be seen that R _trns and R _ct decrease as the conductivity of the electrode and the contact area with the electrolyte increases as the thickness of the composite electrode increases from 1 μm to 4.5 μm. This shows that the composite electrode exhibits the best catalytic properties when it has a thickness of 4.5 탆.

Further, for comparison with the platinum catalyst electrode, a PEDOT: PSS / carbon black composite electrode containing 17 wt% of PEDOT: PSS was prepared to a thickness of 4.5 μm on a glass substrate on which an FTO transparent conductive film was formed by the above- A PEDOT: PSS / carbon black composite electrode containing 17 wt% of PEDOT: PSS was prepared to a thickness of 12 μm on a glass substrate on which no FTO transparent conductive film was formed. Thus, a dye sensitized solar cell . In order to prepare a platinum catalyst electrode, a droplet of hydrogenated platinate (H ₂ PtCl ₆ ) solution was dropped on a glass substrate having an FTO transparent conductive film formed thereon, and then heat treatment was performed at 400 ° C. for 10 minutes to obtain a platinum catalyst having a particle size of 4.5 μm To prepare a dye-sensitized solar cell. The photoelectric conversion efficiency of the dye-sensitized solar cells was measured. FIG. 7 shows the current density-voltage graph. The short-circuit current J _SC , the open-circuit voltage V _OC , (FF) and efficiency are shown in Table 1 below.

division J _SC (mA / cm ² ) V _OC (V) FF (%) efficiency (%) Comparative Example 1 Platinum ┃ FTO glass substrate 15.0 0.80 64.9 7.7 Inventory 1 PEDOT: PSS / carbon black composite < RTI ID = 0.0 > 14.9 0.78 64.1 7.4 Inventory 2 PEDOT: PSS / carbon black composite ┃ Glass substrate 14.0 0.77 55.1 6.0

As shown in Table 1 and FIG. 7, in the case of Inventive Example 1 proposed by the present invention, it can be seen that the photoelectric conversion efficiency is comparable to that of the platinum catalyst electrode (Comparative Example 1), which has been mainly used. This is because the optimum concentration of PEDOT: PSS increases the conductivity of the particles and the number of electron transfer paths, thereby improving the electric conductivity and additionally providing the active site of the catalyst, and the sufficient contact area with the electrolyte due to the sufficient thickness, It is because of bet.

In addition, the conductive polymer-carbon composite electrode proposed by the present invention can also perform the role of collecting electrons of the transparent conductive film. Thus, it is possible to secure excellent electrical conductivity and catalytic activity without forming a transparent conductive film as in Example 2, Type solar cell according to the present invention.

1: first substrate
2: Transparent film
3: oxide semiconductor electrode
4: Dye
5: catalytic electrode
6: second substrate
7: electrolyte
8: Seal material

Claims (24)

A conductive polymer-carbon composite electrode for a dye-sensitized solar cell, comprising a carbon material aggregate having pores and a conductive polymer, wherein all or a part of the conductive polymer is located in pores of the aggregate of carbon material. The method according to claim 1,
Wherein the carbon material is at least one selected from the group consisting of graphite, graphene, carbon nanofiber, carbon nanotube, and carbon black. The method according to claim 1,
The conductive polymer may be at least one selected from the group consisting of polyaniline, polypyrrole, poly (3,4-ethylenedioxythiophene), poly (styrene sulfonate) (PEDOT: PSS), and poly (styrene sulfonate) Wherein the conductive polymer-carbon composite electrode is at least one selected from the group consisting of a metal oxide and a metal oxide. The method according to claim 1,
The conductive polymer-carbon composite electrode for a dye-sensitized solar cell has an average size of 20 to 90 nm as the carbon material constituting the aggregate of carbon material. The method according to claim 1,
Wherein the conductive polymer comprises 1 to 19% by weight of the conductive polymer. Dispersing a conductive polymer in a first solvent to obtain a first solution;
Dispersing a carbon material in a second solvent to obtain a second solution;
Mixing the first solution and the second solution to obtain a composite solution in which the carbon material and the conductive polymer are dispersed; And
And thermally treating the complex solution at 100 to 150 ° C to obtain a composite electrode. The method for manufacturing a conductive polymer-carbon composite electrode for a dye-sensitized solar cell according to claim 1, The method of claim 6,
Wherein the first solvent is at least one selected from the group consisting of isopropanol, ethylenecyclole, and water. The method for producing a conductive polymer-carbon composite electrode for a dye-sensitized solar cell according to claim 1, The method of claim 6,
Wherein the second solvent is at least one selected from the group consisting of isopropanol, methanol and ethanol. The method of claim 6,
Wherein at least one of the step of obtaining the first solution, the step of obtaining the second solution, and the step of obtaining the complex solution is performed by an ultrasonic method or a magnetic stirring method. The method of claim 6,
Further comprising the step of acid-treating the composite electrode after the heat treatment. ≪ RTI ID = 0.0 > 11. < / RTI > The method of claim 10,
The method of manufacturing a conductive polymer-carbon composite electrode for a dye-sensitized solar cell, further comprising the step of heat-treating the composite electrode at 100 to 150 ° C. after the acid treatment. A first substrate;
An oxide semiconductor electrode formed on the first substrate on which dye is adsorbed;
A second substrate facing the oxide semiconductor electrode;
A conductive polymer-carbon composite electrode formed on the second substrate; And
And an electrolyte disposed between the oxide semiconductor electrode and the conductive polymer-carbon composite electrode,
Wherein the conductive polymer-carbon composite electrode comprises a carbon material and a conductive polymer, the carbon material has an aggregated form so as to have a porous structure having pores, and the conductive polymer is provided in the pores. Type solar cell. The method of claim 12,
Wherein the conductive polymer-carbon composite electrode has a thickness of 1 to 15 占 퐉. The method of claim 12,
Wherein the first substrate or the second substrate is one of a glass substrate, a polymer film substrate, and a metal substrate. The method of claim 12,
Wherein a transparent conductive film is additionally formed between the first substrate and the oxide semiconductor electrode. The method of claim 12,
And a transparent conductive film is additionally formed between the second substrate and the conductive polymer-carbon composite electrode. The method according to any one of claims 15 and 16,
Wherein the transparent conductive film is one selected from the group consisting of ZnO, AZO, IZO, GZO, FTO and ITO. The method of claim 12,
Wherein the oxide semiconductor electrode is one of TiO ₂ , SnO _2, and ZnO. The method of claim 12,
Wherein the oxide semiconductor electrode has a thickness of 3 to 20 占 퐉. The method of claim 12,
Wherein the dye is a ruthenium-based dye or an organic dye. Preparing a first substrate;
Forming an oxide semiconductor electrode on the first substrate;
Adsorbing a dye on the oxide semiconductor electrode;
Preparing a second substrate;
Dispersing a conductive polymer in a first solvent to obtain a first solution;
Dispersing a carbon material in a second solvent to obtain a second solution;
Mixing the first solution and the second solution to obtain a composite solution in which the carbon material and the conductive polymer are dispersed;
Applying the composite solution to the second substrate;
Forming a conductive polymer-carbon composite electrode by heat-treating the composite solution at 100 to 150 ° C; And
The method of claim 1, wherein the first substrate and the second substrate are positioned so as to face each other, and then injecting an electrolyte between the first substrate and the second substrate. 23. The method of claim 21,
Wherein the step of preparing the first substrate or the step of preparing the second substrate includes forming a transparent conductive film on the first substrate or the second substrate. 23. The method of claim 21,
Wherein the oxide semiconductor electrode is formed by coating an oxide semiconductor on the first substrate and then heat-treating the oxide semiconductor at 100 to 550 ° C. 23. The method of claim 21,
Wherein the step of applying the composite solution is performed using one of spray coating, drop coating, spin coating, inkjet printing, brush coating and dip coating.

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