KR20110025573A - Dye sensitized solar cell comprising negative electrode including nano oxide layer adsorbed with dye and polyatomic anion and preparation method thereof - Google Patents

Abstract

PURPOSE: A dye sensitized solar cell and a manufacturing method thereof are provided to improve the photo conversion efficiency by comprising the negative electrode including the nano oxide layer. CONSTITUTION: The nano-oxide layer is formed on a transparent substrate(1) on which the transparent conductivity oxide layer is formed. The transparent substrate formed with the nano-oxide layer is dipped in the dye solution which mixes the alkali metal polyatomic anion salt and the organic solvent. A cathode border electrode is manufactured by adsorbing the dye and polyatomic anion(60) on the surface of the nano oxide particle(40).

Description

Dye-sensitized solar cell comprising a cathode-based electrode comprising a nano oxide layer adsorbed with dyes and polyatomic ions and a method for manufacturing the same

The present invention relates to a dye-sensitized solar cell including a cathode-based electrode including a nano oxide layer adsorbed with a dye and a polyatomic ion, and a method of manufacturing the same. The present invention relates to a dye-sensitized solar cell having an improved photoelectric conversion efficiency by including a cathode electrode including a nano oxide layer adsorbed to minimize voids, and a method of manufacturing the same.

Recently, the importance of developing the next generation of clean energy is increasing due to serious environmental pollution and depletion of fossil energy. Among them, solar cell is a device that directly converts solar energy into electrical energy. It is expected to be an energy source that can solve future energy problems due to its low pollution, infinite resources and a semi-permanent life.

The solar cells are classified into materials according to the material, and there are inorganic solar cells, dye-sensitized solar cells, and organic solar cells.

Single crystal silicon is mainly used as an inorganic solar cell, and such single crystal silicon-based solar cell has an advantage of being manufactured as a thin-film solar cell, but has a problem of high cost and low stability.

Dye-sensitized solar cells, unlike conventional silicon solar cells by pn junctions, are capable of absorbing visible light to produce electron-hole pairs and photosensitive dye molecules that deliver the generated electrons. It is a photoelectrochemical solar cell using a transition metal oxide as a main constituent material. Dye-sensitized solar cells can withstand long-term exposure to light and heat, compared to conventional silicon-based solar cells, and can produce energy inexpensively and easily.

As a representative example of dye-sensitized solar cells known so far, there are those published by Gratzel et al. (US Pat. Nos. 4,927,721 and 5,350,644). The dye-sensitized solar cell proposed by Gratzel et al. Consists of a semiconductor electrode composed of nanoparticle titanium dioxide (TiO ₂ ) coated with dye molecules, a counter electrode coated with platinum or carbon, and an electrolyte solution filled between these electrodes. . This photoelectrochemical solar cell has attracted attention due to the low manufacturing cost per power compared to the conventional silicon solar cell. The dye-sensitized solar cell technology developed by Gratzel has proved to be promising as an inexpensive alternative to expensive silicon solar cells.

As described above, dye-sensitized solar cells have advantages in that they are inexpensive to manufacture compared to conventional silicon solar cells and can be applied to glass walls or glass greenhouses for building exterior walls due to transparent electrodes. It is a situation.

Since the photoelectric conversion efficiency of a solar cell is proportional to the amount of electrons generated by the absorption of sunlight, in order to increase the photoelectric conversion efficiency, the production of electrons may be increased by increasing the absorption of sunlight or by increasing the amount of dye adsorption. Alternatively, the generated exciton can be prevented from disappearing by electron-hole recombination.

In order to increase the amount of dye adsorption per unit area, the particles of the oxide semiconductor should be manufactured in nanometer size, and the reflectance of the platinum electrode may be increased to increase the absorption of sunlight, or the light scatterer may be mixed with several micro-sized oxide semiconductors. Methods have been developed. However, such a conventional method has a limitation in improving the photoelectric conversion efficiency of the solar cell, and thus, there is an urgent demand for developing a new technology for improving the efficiency.

The present inventors have sought ways to improve the photoelectric conversion efficiency of the dye-sensitized solar cell, and as a result of intensive studies to improve the voltage drop phenomenon that reduces the photoelectric conversion efficiency of the dye-sensitized solar cell, the cathode of the dye-sensitized solar cell When manufacturing a nano electrode layer by adsorbing dye and specific polyatomic ions to the surface of the nano oxide particles to minimize the surface space when manufacturing the electrode, it is found that the voltage can be increased to improve the photoelectric conversion efficiency of the dye-sensitized solar cell. The present invention has been completed.

SUMMARY OF THE INVENTION An object of the present invention is to provide a dye-sensitized solar cell having improved photoelectric conversion efficiency and a method of manufacturing the same, which can improve low photoelectric conversion efficiency, which is a problem of dye-sensitized solar cells.

In order to achieve the above object, the present invention,

Forming a nano oxide layer on the transparent substrate on which the transparent conductive oxide layer is formed (step 1);

dyes; Lithium Phosphate (Li ₃ PO ₄ ), Lithium Carbonate (Li ₂ CO ₃ ), Lithium Sulphate (Li ₂ SO ₄ ), Lithium Dibasic Sodium Phosphate (LiH ₂ PO ₄ ), Sodium Phosphate (Na ₃ PO ₄ ) and Monosodium Phosphate (NaH ₂ PO ₄ ) adsorbs the dye and the polyatomic ion on the surface of the nano oxide particles by supporting a transparent substrate having the nano oxide layer formed on a dye solution mixed with an alkali metal polyatomic anion salt selected from the group consisting of (NaH ₂ PO ₄ ). Preparing a cathode electrode (step 2);

Preparing a bipolar electrode by forming a metal layer on the transparent substrate on which the transparent conductive oxide layer is formed (step 3); And

It provides a method of manufacturing a dye-sensitized solar cell comprising a step (step 4) of injecting an electrolytic solution after the anode electrode prepared in step 2 and the anode electrode prepared in step 3 are bonded to each other.

In addition, the present invention provides a dye-sensitized solar cell comprising a negative electrode having a nano-oxide layer on which the dye and polyatomic ions are adsorbed on the surface of the nano-oxide particles.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The present invention,

Forming a nano oxide layer on the transparent substrate on which the transparent conductive oxide layer is formed (step 1);

dyes; Lithium Phosphate (Li ₃ PO ₄ ), Lithium Carbonate (Li ₂ CO ₃ ), Lithium Sulphate (Li ₂ SO ₄ ), Lithium Dibasic Sodium Phosphate (LiH ₂ PO ₄ ), Sodium Phosphate (Na ₃ PO ₄ ) and Monosodium Phosphate (NaH ₂ PO ₄ ) by adsorbing a dye and polyatomic ion on the surface of the nano-oxide particles by supporting a transparent substrate having the nano-oxide layer in a dye solution mixed with an alkali metal polyatomic anion salt selected from the group consisting of (NaH ₂ PO ₄ ) Preparing a cathode electrode (step 2);

Preparing a bipolar electrode by forming a metal layer on the transparent substrate on which the transparent conductive oxide layer is formed (step 3); And

It provides a method of manufacturing a dye-sensitized solar cell comprising a step (step 4) of injecting an electrolytic solution after the anode electrode prepared in step 2 and the anode electrode prepared in step 3 are bonded to each other.

Hereinafter, a method of manufacturing a dye-sensitized solar cell according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a side cross-sectional view of a dye-sensitized solar cell prepared according to one embodiment of the invention.

Step 1 is a step of forming a nano oxide layer on a transparent substrate on which a transparent conductive oxide layer is formed.

As the transparent substrate 1 used in the present invention, a glass substrate or a transparent plastic substrate may be used, and the transparent plastic substrate may be polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethylene (PE), or polyether. Sulfon (PES), polycarbonate (PC), polyarylate (PAR), polyimide (PI) and the like can be used, but is not limited thereto.

A transparent conductive oxide layer is formed on the transparent substrate 1, and as the material of the transparent conductive oxide layer, fluorine-doped tin oxide (FTO), indium tin oxide (ITO), indium zinc oxide (IZO), and indium Zinc Tin Oxide (IZTO), Aluminum Zinc Oxide (AZO), Indium Tin Oxide-Silver-Indium Tin Oxide (ITO-Ag-ITO), Indium Zinc Oxide-Silver-Indium Zinc Oxide (IZO-Ag-IZO), Indium Zinc Tin oxide-silver-indium zinc tin oxide (IZTO-Ag-IZTO), aluminum zinc oxide-silver-aluminum zinc oxide (AZO-Ag-AZO) and the like can be used, in particular fluorine-doped tin oxide (FTO) desirable. The transparent conductive oxide layer can be formed by any one of sputtering, chemical vapor deposition (CVD), evaporation, thermal oxidation, and electrochemical anodization (deposition). have.

Thereafter, a nano oxide layer is formed on the transparent conductive oxide layer. The nano oxide layer may be provided with a transition metal oxide, in particular titanium dioxide, a composition containing titanium dioxide may be applied by a doctor blade method, a screen printing method and the like.

Step 2 comprises a dye; Lithium Phosphate (Li ₃ PO ₄ ), Lithium Carbonate (Li ₂ CO ₃ ), Lithium Sulphate (Li ₂ SO ₄ ), Lithium Dibasic Sodium Phosphate (LiH ₂ PO ₄ ), Sodium Phosphate (Na ₃ PO ₄ ) and Monosodium Phosphate (NaH ₂ PO ₄ ) on the surface of the nano oxide particles (40) by carrying a transparent substrate (1) having the nano oxide layer formed on a dye solution mixed with an alkali metal polyatomic anion salt selected from the group consisting of (NaH ₂ PO ₄ ) 50) and preparing a negative electrode by adsorbing the polyatomic ion 60, which corresponds to a key step in the manufacturing method of the dye-sensitized solar cell of the present invention.

In one embodiment of the present invention, the dye solution may be prepared by dissolving 50 to 95% by weight of the dye and 5 to 50% by weight of the alkali metal polyatomic anion salt in an organic solvent.

Ethanol, methanol, propanol, isopropanol, acetonitrile, etc. may be used as the organic solvent, and as a dye, a material capable of absorbing visible light, including a ruthenium (Ru) complex, may be used. Of course, it is possible to use dyes that improve and improve efficiency and new types of dyes that are easy to emit electrons.

After the transparent substrate 1 having the nano oxide layer prepared in step 1 was formed in a dye and a dye solution in which the alkali metal polyatomic anion salt was dissolved, the dye 50 and the polyatomic ion 60 were nano oxide particles. The cathode 10 is manufactured by adsorbing dyes and polyatomic ions to the surface of the nano-oxide particles 40 so as to minimize the surface blanks by maintaining them for a time enough to be adsorbed on the surface of the 40.

Step 3 is a step of forming a bipolar electrode 20 by forming a metal layer 30 on the transparent substrate 1 on which a transparent conductive oxide layer is formed.

As in step 1, the transparent conductive oxide layer may be formed on the transparent substrate 1, and then the anode layer 20 may be manufactured by forming the metal layer 30 on the transparent conductive oxide layer.

The metal layer 30 is made of a material that can be energized. Preferably, the metal layer 30 may be made of a precious metal material such as platinum (Pt). Platinum (Pt) has a good reflectivity, the transmitted visible light is reflected into the interior of the solar cell is advantageous for the efficiency of light absorption. In addition, in addition to platinum (Pt), other precious metal materials having a low resistance value can also be used.

Step 4 is a step of injecting an electrolyte after bonding the cathode-based electrode 10 prepared in Step 2 and the anode-based electrode 20 prepared in Step 3 to face each other.

In one embodiment of the present invention, the cathode-based electrode 10 and the anode-based electrode 20 are opposed to each other, and then the hole is formed by injecting electrolyte by forming fine holes in the anode-based electrode 20. The dye-sensitized solar cell can be manufactured by sealing using a polymer resin.

The present invention is a dye; Lithium Phosphate (Li ₃ PO ₄ ), Lithium Carbonate (Li ₂ CO ₃ ), Lithium Sulphate (Li ₂ SO ₄ ), Lithium Dibasic Sodium Phosphate (LiH ₂ PO ₄ ), Sodium Phosphate (Na ₃ PO ₄ ) and Monosodium Phosphate The dye and polyatomic ions are adsorbed on the surface of the nano oxide particles by supporting a transparent substrate having the nano oxide layer formed on a dye solution mixed with an alkali metal polyatomic anion salt selected from the group consisting of (NaH ₂ PO ₄ ) and an organic solvent. It provides a negative electrode of the dye-sensitized solar cell, including a nano oxide layer.

In addition, the present invention is a dye; Lithium Phosphate (Li ₃ PO ₄ ), Lithium Carbonate (Li ₂ CO ₃ ), Lithium Sulphate (Li ₂ SO ₄ ), Lithium Dibasic Sodium Phosphate (LiH ₂ PO ₄ ), Sodium Phosphate (Na ₃ PO ₄ ) and Monosodium Phosphate The dye and polyatomic ions are adsorbed on the surface of the nano oxide particles by supporting a transparent substrate having the nano oxide layer formed on a dye solution mixed with an alkali metal polyatomic anion salt selected from the group consisting of (NaH ₂ PO ₄ ) and an organic solvent. It provides a dye-sensitized solar cell comprising a negative electrode formed with a nano oxide layer.

The method of forming the nano oxide layer in which the dye and polyatomic anion are adsorbed on the surface of the nano oxide particles in the cathode electrode is as described above.

2 is a side cross-sectional view of a conventional dye-sensitized solar cell. 1 and 2, in the dye-sensitized solar cell 100 manufactured according to the present invention, a dye 50 and a polyatomic ion 60 are formed on the surface of the nano-oxide particle 40 in the negative electrode 10. Is adsorbed to minimize surface blanks (see FIG. 1). However, the method of manufacturing the negative electrode 10 of the dye-sensitized solar cell according to the prior art does not allow dyes to be adsorbed by minimizing surface porosity on the surface of the nano-oxide particles 40, as shown in FIG. 2. ) Is adsorbed sparsely on the surface of the nano oxide particles 40.

In the dye-sensitized solar cell of the present invention including a negative electrode having a nano-oxide layer on which the dye and polyatomic ions are adsorbed on the surface of the nano-oxide particles to minimize surface blanks, the dye is sparsely adsorbed on the surface of the nano-oxide particles. Compared with the dye-sensitized solar cell including the cathode-based electrode having the nano oxide layer formed thereon, the open voltage and the filling coefficient are improved, thereby improving the photoelectric conversion efficiency. This effect is explained in more detail below.

The present invention provides a dye-sensitized solar cell and a method for manufacturing the same, including a cathode-based electrode having a nano-oxide layer having a dye and polyatomic ions adsorbed on the surface of the nano-oxide particles to minimize surface space. Sensitized solar cells can be improved in the open-circuit voltage and the filling factor can be improved photoelectric conversion efficiency.

Hereinafter, preferred examples are provided to aid the understanding of the present invention, but the following examples are merely for exemplifying the present invention, and it will be apparent to those skilled in the art that various changes and modifications can be made within the scope and spirit of the present invention. It is natural that such variations and modifications fall within the scope of the appended claims.

< Example >

Example  One

(1) A transparent glass substrate on which a fluorine-doped tin oxide transparent conductive oxide layer was formed was prepared. Applying a coating composition comprising titanium dioxide on the transparent conductive oxide layer of the substrate by a doctor blade method, and heat-treated at 500 ℃ for 30 minutes, so that the contact and filling between nano-sized metal oxide is made to about 8 ㎛ A thick nano oxide layer was formed. Subsequently, a coating composition including titanium dioxide was applied to the upper portion of the nano oxide layer by the same method, and heat-treated at a temperature of 500 ° C. for 30 minutes to form a nano oxide layer having a thickness of about 15 μm. A dye solution in which 0.2 mM ruthenium dithiocyanate 2,2'-bipyridyl-4,4'-dicarboxylate and 0.2 mM lithium phosphate (Li ₃ PO ₄ ) was dissolved in ethanol was prepared. The substrate having the nano oxide layer formed thereon was supported for 24 hours and then dried to adsorb dyes and phosphate ions to the nano-sized metal oxide to prepare a negative electrode.

(2) A transparent glass substrate on which a fluorine-doped tin oxide transparent conductive oxide layer was formed was prepared. A 2-propanol solution in which chloroplatinic acid (H ₂ PtCl ₆ ) was dissolved was dropped on the transparent conductive oxide layer of the substrate, and then thermally treated at 450 ° C. for 30 minutes to form a platinum layer, thereby preparing an anode-based electrode.

(3) After the nano-oxide layer of the prepared cathode electrode and the platinum layer of the anode electrode were opposed to each other, a thermoplastic polymer layer having a thickness of about 60 μm made of SURLYN (manufactured by Du Pont) was formed, and then 130 Placed in an oven at ℃ ℃ was kept for 2 minutes to attach and seal the two electrodes. Next, fine holes penetrating the cathode electrode and the anode electrode were formed, an electrolyte solution was injected into the space between the two electrodes through the hole, and then the outside of the hole was sealed with an adhesive. Here, the electrolyte solution is 0.1M LiI, 0.05MI ₂ , 0.5M 4-tert-butylpyridine in a 3-Methoxypropionitrile solvent and 0.6M 1 as an ionic liquid. -Ethyl-1-methylpyrrolidinium iodide (1-Ethyl-1-methylpyrrolidinium iodide) was prepared by melting.

Comparative example  One

In preparing the dye solution, the same method as in Example 1 except for preparing a dye solution in which 0.2 mM ruthenium dithiocyanate 2,2'-bipyridyl-4,4'-dicarboxylate was prepared. Was carried out.

Test Example

In order to evaluate the photoelectric conversion efficiency of the dye-sensitized solar cells prepared in Example 1 and Comparative Example 1 by measuring the optical voltage and photocurrent in the following manner to observe the photoelectric characteristics, the current density obtained through this (I _sc ), The voltage (V _oc ), and the fill factor (ff factor) to calculate the photoelectric conversion efficiency (η _e ) by the following equation (1).

At this time, Xenon lamp (Oriel) was used as the light source, and the solar condition (AM 1.5) of the xenon lamp was corrected using a standard solar cell.

η _e = (V _oc × I _sc × ff) / (P _ine )

In Equation 1, (P _ine ) represents 100 ㎽ / ㎠ (1 sun).

The values measured as above are shown in Table 1 below.

division Current density (㎃ / cm ² ) Open Voltage (Voc) Fill factor Photoelectric conversion efficiency (%) Example 1 14.640 0.705 0.625 6.454 Comparative Example 1 14.725 0.650 0.606 5.801

As shown in Table 1, the dye-sensitized solar cell prepared by the dye solution containing a lithium phosphate salt prepared using Example 1 according to the present invention is a solution in which only the dye used in the prior art as in Comparative Example 1 is dissolved Compared with the dye-sensitized solar cell manufactured by using the open voltage and the filling coefficient was confirmed that the improved photoelectric conversion efficiency.

1 is a side cross-sectional view of a dye-sensitized solar cell prepared according to one embodiment of the invention.

2 is a side cross-sectional view of a conventional dye-sensitized solar cell.

Explanation of symbols on the main parts of the drawings

1: transparent substrate 100: dye-sensitized solar cell

10: cathode electrode 20: anode electrode

30: metal layer 40: nano oxide particles

50: dye 60: polyatomic ion

Claims (14)

Forming a nano oxide layer on the transparent substrate on which the transparent conductive oxide layer is formed (step 1); dyes; Lithium Phosphate (Li ₃ PO ₄ ), Lithium Carbonate (Li ₂ CO ₃ ), Lithium Sulphate (Li ₂ SO ₄ ), Lithium Dibasic Sodium Phosphate (LiH ₂ PO ₄ ), Sodium Phosphate (Na ₃ PO ₄ ) and Monosodium Phosphate (NaH ₂ PO ₄ ) by adsorbing a dye and polyatomic ion on the surface of the nano-oxide particles by supporting a transparent substrate having the nano-oxide layer in a dye solution mixed with an alkali metal polyatomic anion salt selected from the group consisting of (NaH ₂ PO ₄ ) Preparing a cathode electrode (step 2); Preparing a bipolar electrode by forming a metal layer on the transparent substrate on which the transparent conductive oxide layer is formed (step 3); And A method of manufacturing a dye-sensitized solar cell comprising the step of injecting an electrolyte after bonding the cathode electrode prepared in step 2 and the anode electrode prepared in step 3 so as to face each other. The method of claim 1, The dye solution is a method for producing a dye-sensitized solar cell, characterized in that the dye is prepared by dissolving 50 to 95% by weight of the dye and 5 to 50% by weight of the alkali metal polyatomic anion salt. The method of claim 2, The organic solvent is a method of manufacturing a dye-sensitized solar cell, characterized in that selected from the group consisting of ethanol, methanol, propanol, isopropanol and acetonitrile. The method of claim 2, The dye is a method for producing a dye-sensitized solar cell, characterized in that the ruthenium-based dye. The method of claim 1, The transparent conductive oxide layer is fluorine-doped tin oxide (FTO), indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), aluminum zinc oxide (AZO), indium tin oxide-silver Indium tin oxide (ITO-Ag-ITO), indium zinc oxide-silver-indium zinc oxide (IZO-Ag-IZO), indium zinc oxide-silver-indium zinc tin oxide (IZTO-Ag-IZTO) and aluminum zinc Method of manufacturing a dye-sensitized solar cell, characterized in that formed of a transparent conductive oxide selected from the group consisting of oxide-silver-aluminum zinc oxide (AZO-Ag-AZO). The method of claim 1, The transparent substrate is a glass substrate or a transparent plastic substrate manufacturing method of the dye-sensitized solar cell, characterized in that. The method of claim 1, The metal layer is a method of manufacturing a dye-sensitized solar cell, characterized in that the platinum layer. The method of claim 1, The nano oxide layer is a method of manufacturing a dye-sensitized solar cell, characterized in that formed by applying a coating composition containing titanium dioxide. As a negative electrode of a dye-sensitized solar cell, The cathode electrode is a dye; Lithium Phosphate (Li ₃ PO ₄ ), Lithium Carbonate (Li ₂ CO ₃ ), Lithium Sulphate (Li ₂ SO ₄ ), Lithium Dibasic Sodium Phosphate (LiH ₂ PO ₄ ), Sodium Phosphate (Na ₃ PO ₄ ) and Monosodium Phosphate The dye and polyatomic ions are adsorbed onto the surface of the nano-oxide particles by supporting a transparent substrate having the nano-oxide layer in a dye solution mixed with an alkali metal polyatomic anion salt selected from the group consisting of (NaH ₂ PO ₄ ) and an organic solvent. Cathode electrode of a dye-sensitized solar cell comprising a nano oxide layer. 10. The method of claim 9, The nano-oxide particle is a cathode electrode of a dye-sensitized solar cell, characterized in that the titanium dioxide particles. 10. The method of claim 9, The dye is a negative electrode of the dye-sensitized solar cell, characterized in that the ruthenium-based dye. As a dye-sensitized solar cell, The dye-sensitized solar cell is a dye; Lithium Phosphate (Li ₃ PO ₄ ), Lithium Carbonate (Li ₂ CO ₃ ), Lithium Sulphate (Li ₂ SO ₄ ), Lithium Dibasic Sodium Phosphate (LiH ₂ PO ₄ ), Sodium Phosphate (Na ₃ PO ₄ ) and Monosodium Phosphate The dye and polyatomic ions are adsorbed on the surface of the nano oxide particles by supporting a transparent substrate having the nano oxide layer formed on a dye solution mixed with an alkali metal polyatomic anion salt selected from the group consisting of (NaH ₂ PO ₄ ) and an organic solvent. Dye-sensitized solar cell comprising a negative electrode having a nano-oxide layer formed. The method of claim 12, Dye-sensitized solar cell, characterized in that the nano oxide particles are titanium dioxide particles. The method of claim 12, The dye-sensitized solar cell, characterized in that the ruthenium-based dye.

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