KR20090123197A - Preparation method of titanium dioxide powder doped with erbium ion and ytterbium ion and its application to dye-sensitized solar cell as scattering layer - Google Patents

Abstract

PURPOSE: A method for manufacturing a titanium dioxide powder doped with Er^3+ and Yb^3+, and a dye-sensitized solar cell using the titanium dioxide powder are provided to improve scattering, thereby enhancing the efficiency of a dye-sensitized solar cell. CONSTITUTION: A method for manufacturing a titanium dioxide powder doped with Er^3+ and Yb^3+ comprises the steps of (S1) mixing titanium isopropoxide, erbium (III) nitrate (Er(NO3)3), ytterbium (III) nitrate (Yb(NO3)3) and carbon black in a solvent to prepare a mixture; (S2) forming a gel with adding water to the mixture; (S3) drying the gel to prepare a precursor; and (S4) heat treating the precursor. The solvent is a mixture solvent comprising acetic acid and ethanol.

Description

Preparation Method of Titanium Dioxide Powder Doped with Erbium Ion and Ytterbium Ion and Dye-Sensitized Solar Cell Applying It as Scattering Layer }

The present invention relates to a method for producing titanium dioxide powder, and more particularly, to a method of preparing titanium dioxide powder doped with Er ³⁺ and Yb ³⁺ and a dye-sensitized application of titanium dioxide powder prepared by the same method as a scattering layer. It relates to a solar cell.

Dye-sensitized solar cells, developed in 1991 by Gratzel et al., Switzerland, are photosensitive dye molecules capable of absorbing visible light to produce electron-hole pairs, and nanocrystals that deliver the resulting electrons. As a photoelectrochemical solar cell using an oxide semiconductor electrode made of oxidized titanium oxide particles, it is also called a dye-sensitized solar cell or a wet solar cell. Such a solar cell has a feature of having a photoelectric conversion efficiency that is simpler in manufacturing process, lower in manufacturing cost, and practically usable as compared with a silicon type solar cell, and many studies have been conducted.

1 is a cross-sectional view of a general dye-sensitized solar cell, which is divided into a negative electrode 100, a positive electrode 200, and a liquid electrolyte 300. The negative electrode 100 includes a transparent substrate 110 and a transparent conductive oxide layer (eg, fluorine-doped tin oxide (FTO) or indium tin oxide (ITO) 120 formed on the transparent substrate). It has a structure consisting of the nano oxide layer 130 adsorbed porous dye on the substrate. The positive electrode 200 is formed of a platinum catalyst which serves to promote a reduction reaction of an electrolyte in a liquid electrolyte on a conductive transparent substrate including a transparent substrate 210 and a transparent conductive oxide layer 220 formed on the transparent substrate. It has a structure consisting of a layer 230. The liquid electrolyte 300 is generally a solution in which the electrolyte is dissolved, and is placed in the thermoplastic polymer layer 400 placed to form a space between the negative electrode 100 and the positive electrode 200 and is in contact with the positive electrode. have. The dye-sensitized solar cell having such a structure irradiates light from the negative electrode 100 to allow electrons from the negative electrode 100 to pass through the external circuit and back to the positive electrode 200.

In the dye-sensitized solar cell, the light conversion process is irradiated light energy is absorbed by the dye of the negative electrode 100, the dye is activated to generate holes and electrons. The generated electrons are transferred back to the transparent conductive oxide layer 120 through the nano oxide layer 130, move to the circuit connected to the positive electrode 200 through the circuit connected to the transparent conductive oxide layer 120, and the positive electrode ( It is delivered to the liquid electrolyte 300 again through 200. On the other hand, the holes generated together with the electrons are passed through the liquid electrolyte 300 is made of a process of recombining with the electrons returned through the positive electrode (200).

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

In order to increase the amount of dye adsorption per unit area, oxide semiconductor particles should be manufactured in nanometer size, and a method of increasing the reflectance of the platinum electrode has been developed to increase the absorption of sunlight. However, such a conventional method has a limitation in improving the light conversion efficiency of the solar cell, and thus, there is an urgent demand for the development of a new technology for improving the efficiency.

The technical problem to be solved by the present invention is to use a method for producing titanium dioxide powder doped with Er ³⁺ and Yb ³⁺ can be used in the scattering layer of the dye-sensitized solar cell and the same method It is to provide a dye-sensitized solar cell comprising a scattering layer formed from a titanium dioxide powder prepared by.

In order to solve the above technical problem, the present invention provides a titanium isopropoxide, erbium (III) nitrate (Er (NO ₃ ) ₃ ) and ytterbium (III) nitrate (Yb (NO ₃ ) in a solvent (S1). ₃ ) and carbon black to prepare a mixture; (S2) stirring to add water to the mixture to form a gel; (S3) drying the gel to prepare a precursor; And (S4) provides a method for producing a titanium dioxide powder doped with Er ³⁺ and Yb ³⁺ comprising the step of heat-treating the precursor.

The invention also provides a transparent substrate (A); A transparent conductive oxide layer formed on the transparent substrate; And a negative electrode formed on the transparent conductive oxide layer and including a nano oxide layer to which dye is adsorbed; (B) a transparent substrate; A transparent conductive oxide layer formed on the transparent substrate; And a platinum layer formed on the transparent conductive oxide layer. (C) a scattering layer formed on the nano-oxide layer of the negative electrode, comprising a titanium dioxide powder doped with Er ³⁺ and Yb ³⁺ ; And (D) provides a dye-sensitized solar cell comprising an electrolyte interposed between the negative electrode and the positive electrode.

When the titanium dioxide powder doped with Er ³⁺ and Yb ³⁺ is prepared and applied to the scattering layer by the method according to the present invention, embossed protrusions are formed on the surface of the powder, so that scattering is more efficiently performed, thereby improving the efficiency of the dye-sensitized solar cell. Can be improved.

Hereinafter, the present invention will be described in detail.

Figure 2 is a process flow diagram of a method for manufacturing an Er ³⁺ and Yb ³⁺ doped titanium dioxide powder according to the invention.

As shown in FIG. 2, the method for preparing titanium dioxide powder of the present invention includes titanium isopropoxide, erbium (III) nitrate (Er (NO ₃ ) ₃ ) and ytterbium (III) nitrate (S1) in a solvent. Mixing Yb (NO ₃ ) ₃ ) and carbon black to prepare a mixture; (S2) stirring to add water to the mixture to form a gel; (S3) drying the gel to prepare a precursor; And (S4) heat treating the precursor. Titanium dioxide powder produced through this is doped with Er ³⁺ and Yb ³⁺ , it can be used in the production of the scattering layer of the dye-sensitized solar cell can improve the light conversion efficiency of the dye-sensitized solar cell.

The solvent may be a mixed solvent including for example acetic acid and ethanol. The content of acetic acid and ethanol in the mixed solvent is not particularly limited, but considering the solubility of each additive material is preferably 1 to 20% by volume, 80 to 99% by volume based on the total volume of the mixed solvent.

The content of each additive in the mixture is not particularly limited, but erbium (III) nitrate (Er (NO ₃ ) ₃ ) and ytterbium (III) nitrate (Yb (NO ₃ ) ₃ ) are titanium isopropoxide, respectively. 5 to 20 mol% is added based on the number of moles, and carbon black exhibits the best physical properties when 10 to 200 parts by weight is added to 100 parts by weight of titanium isopropoxide.

For example, any one or more selected from the group consisting of acetylene black, furnace black, and super P may be used as the carbon black.

The drying temperature in the step (S3) is preferably 100 ~ 130 ℃. If the drying temperature is less than the lower limit of the above range, it is not preferable because the gel is not easily removed, and if the drying temperature is exceeded, it is difficult to handle and dangerous.

In the step (S4), the heat treatment temperature is preferably 600 to 800 ° C. When the heat treatment temperature falls below the lower limit of the above range, the size of the particles may be too small, and when the heat treatment temperature is exceeded, the crystalline particles may be excessively large and difficult to function as a scattering layer.

Figure 2 shows a cross-sectional view of the dye-sensitized solar cell according to an embodiment of the present invention.

As shown in Figure 2, the dye-sensitized solar cell according to an embodiment of the present invention is formed on the (A) the negative electrode 100, (B) the positive electrode 200, (C) the nano oxide layer of the negative electrode Scattering layer 500 and (D) comprises an electrolyte 400 interposed between the negative electrode and the positive electrode.

(A) The negative electrode 100 is a transparent substrate 110; A transparent conductive oxide layer 120 formed on the transparent substrate; And a nano oxide layer formed on the transparent conductive oxide layer and having a dye adsorbed thereon.

The transparent substrate 110 is polyethersulfone, polyacrylate, polyetherimide, polyethylene naphthalate, polyethylene terephthalate, polyphenylene sulfide, polyarylate, polyimide, polycarbonate, cellulose triacetate and cellulose acetate propio It may be a plastic material or a glass material containing at least one selected from the group consisting of nates.

The transparent conductive oxide layer 120 is a layer formed from fluorine-doped indium tin oxide (FTO) or indium tin oxide (ITO).

The nano oxide layer 130 is formed from a composition containing at least one metal oxide selected from the group consisting of titanium dioxide (TiO ₂ ), tin dioxide (SnO ₂ ), and zinc oxide (SnO), in which dye is adsorbed. Layer. The nano oxide layer 130 preferably has a thickness of 5 to 30 μm.

The dye may be adsorbed using a solution containing a ruthenium complex or an organic dye. Dyes include ruthenium complexes that can absorb visible light, including ruthenium complexes, as well as dyes that can improve long-wave absorption in visible light to improve efficiency and efficiently emit electrons. Of course. Specifically, xanthine-based dyes such as rhodamine B, rosebengal, eosin, erythrosin and the like; Cyanine-based dyes such as quinocyanine and cryptocyanine; Basic dyes such as phenosafranin, cabrioblue, thiocin and methylene blue; Porphyrin-based compounds such as chlorophyll, zinc porphyrin, and magnesium porphyrin; Other azo dyes; Phthalocyanine compounds; Anthraquinone dyes; Or polycyclic quinone dye etc. can be used individually or in mixture of 2 or more types.

(B) the positive electrode 200 is a transparent substrate 210; A transparent conductive oxide layer 220 formed on the transparent substrate; And a platinum layer 230 formed on the transparent conductive oxide layer.

The transparent substrate 210 and the transparent conductive oxide layer 220 are the same as those mentioned in the negative electrode, and the platinum layer 230 is a layer formed from a platinum catalyst which serves to promote a reduction reaction of the electrolyte.

(C) The scattering layer 500 formed on the nano-oxide layer of the negative electrode includes titanium dioxide powder doped with Er ³⁺ and Yb ³⁺ . The scattering layer is a layer that increases the efficiency of the solar cell by reflecting light transmitted through the negative electrode and supplying light back to the negative electrode layer.The amorphous powder is formed by doping the titanium dioxide powder with Er ³⁺ and Yb ^3+. Embossed protrusions are formed on the surface, so that scattering is more efficiently performed, thereby improving light conversion efficiency.

(D) The electrolyte is interposed between the negative electrode and the positive electrode, and a liquid electrolyte, an inorganic solid electrolyte, a polymer solid electrolyte, a gel polymer electrolyte, and the like can be used without limitation. As a representative example, a liquid electrolyte composed of a pair of iodide and triiodide may be used.

Hereinafter, the manufacturing method of the dye-sensitized solar cell of the present invention will be described. However, this is merely an example and the manufacturing method of the dye-sensitized solar cell of the present invention is not limited only to the following description.

First, a negative electrode is manufactured.

The manufacturing of the negative electrode may include preparing a transparent substrate; Forming a transparent conductive oxide layer on the prepared transparent substrate; Forming a nano oxide layer by applying a composition including a metal oxide on top of the formed transparent conductive oxide layer; And adsorbing the dye by applying a solution in which the dye is dissolved in the formed nano oxide layer.

Specifically, first, after preparing a transparent substrate, indium tin oxide or indium tin oxide doped with a transparent conductive oxide, which is doped with a transparent conductive oxide, is coated on the top of the transparent substrate using an adhesive or coated by a sputtering method to form a transparent conductive oxide. A layer can be formed. Next, in order to form a nano oxide layer, after preparing a coating composition comprising at least one metal oxide selected from the group consisting of titanium dioxide (TiO ₂ ), tin dioxide (SnO ₂ ) and zinc oxide (SnO), The coating composition may be applied to the upper portion of the formed transparent conductive metal layer by a doctor blade method, and thermally treated at a temperature of 400 to 500 ° C. for 10 to 60 minutes to form a nano oxide layer having a thickness of 5 to 30 μm. In this case, the step of forming the nano oxide layer may be repeated one or more times to form a nano oxide layer having a desired thickness. Next, in order to adsorb the dye to the metal oxide of the formed nano oxide layer, the dye is dissolved in a solvent to prepare a dye solution having a concentration of 0.01 to 5 μM, and then the substrate on which the nano oxide layer is formed is 5 to 5. The dye may be adsorbed by drying for 72 hours and then drying.

Next, a positive electrode is manufactured.

The manufacturing of the positive electrode may include preparing a transparent substrate; Forming a transparent conductive oxide layer on the prepared transparent substrate; And forming a platinum layer on the formed transparent conductive oxide layer.

Specifically, first, after preparing a transparent substrate, indium tin oxide or indium tin oxide doped with fluorine, which is a transparent conductive oxide, is adhered to the upper portion of the transparent substrate by using an adhesive or by coating a coating film by sputtering to form a transparent conductive oxide. A layer can be formed. Next, after the solution in which the platinum is dissolved on the upper portion of the transparent conductive oxide layer is dropped, the platinum layer may be formed by heat treatment at 400 to 600 ° C. for 10 to 60 minutes. In this case, the platinum layer may be formed using a sputtering method, a chemical vapor deposition method, a vapor deposition method, a thermal oxidation method, an electrochemical deposition method.

Next, a scattering layer is formed on the nano oxide layer of the negative electrode.

Forming the scattering layer comprises the steps of preparing titanium dioxide powder; Preparing a slurry using the titanium dioxide powder; And applying the slurry on top of the nano oxide layer of the negative electrode.

Specifically, a titanium dioxide powder doped with Er ³⁺ and Yb ³⁺ is prepared in the same manner as described above. A solvent, such as ethanol, is added to the prepared titanium dioxide powder and dispersed by sonication. Ethyl cellulose was added thereto, sonicated and dispersed, terpinol was added, and the solvent was evaporated to prepare a slurry for forming a scattering layer. Next, the prepared slurry may be applied on the nano oxide layer of the negative electrode by a doctor blade method or the like and heat treated to form a scattering layer.

Next, the negative electrode and the positive electrode are attached.

Specifically, the conductive surfaces of the negative electrode and the positive electrode are brought inward, and they are attached to face each other. A thermoplastic polymer layer having a thickness of 20 to 100 μm may be formed between the negative electrode and the positive electrode, and the two electrodes may be sealed using the thermoplastic polymer layer. As the thermoplastic polymer layer, for example, SURLYN (manufactured by Du Pont) may be used.

Next, an electrolyte is injected between the negative electrode and the positive electrode.

As the electrolyte, a liquid electrolyte, an inorganic solid electrolyte, a polymer solid electrolyte, a gel polymer electrolyte, or the like may be used without limitation. As a representative example, a liquid electrolyte composed of a pair of iodide and triiodide may be used. After the electrolyte injection, the fine holes formed for the electrolyte injection are sealed.

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 1

2 ml of acetic acid is mixed with 16 ml of ethanol and 3.4 ml of titanium isopropoxide, and erbium (III) nitrate (Er (NO ₃ ) ₃ ) and ytterbium (III) nitrate (Yb (NO ₃ ) ₃ ) are respectively added. 10 mol% (based on titanium isopropoxide) and 0.2 g of acetylene black were added and mixed. The mixed solution thus prepared was mixed while dropping 1.0 ml of pure water over 30 minutes while stirring. Thereafter, the mixed solution was vacuum dried at 120 ° C., and the dried material was heat-treated at a temperature of 700 ° C. for 4 hours to obtain titanium dioxide powder doped with Er ³⁺ and Yb ³⁺ .

A slurry for application to the working electrode was then prepared using the prepared titanium dioxide powder. 50 ml of ethanol was added to 2.5 g of the powder, followed by ultrasonication for 60 minutes to disperse. 0.75 g of ethyl cellulose was added thereto, sonicated at 35 ° C. for 60 minutes to disperse, and 5 ml of terpineol was added, followed by evaporation of the solvent in an evaporator to obtain a slurry for preparing a scattering layer.

Separately, the titanium dioxide coating slurry was coated on a transparent conductive substrate (TCO) coated with fluorine tin oxide (FTO) by a doctor blade method, followed by heat treatment at a temperature of about 500 ° C. for 30 minutes to exclude nano polymers. A conductive transparent substrate having a titanium dioxide layer having a thickness of about 8 microns was formed by contacting and filling particle oxides.

The slurry prepared for use as a scattering layer on the conductive transparent substrate on which the titanium dioxide layer was formed was coated by a doctor blade method, and then heat-treated at a temperature of about 500 ° C. for 30 minutes. The conductive transparent substrate thus formed was immersed in a ruthenium dithiocyanate 2,2'-bipyridyl-4,4'-dicarboxylate dye solution having a concentration of 0.2 mM for 24 hours to prepare a negative electrode and a scattering layer.

Separately, a 2-propanol solution in which chloroplatinic acid (H ₂ PtCl ₆ ) is dissolved is dropped on a transparent conductive substrate (TCO) coated with fluorine tin oxide (FTO), followed by heat treatment at 400 ° C. for 30 minutes to prepare a positive electrode. It was.

Subsequently, a transparent substrate coated with a titanium dioxide layer and a scattering layer on which a dye, a positive electrode and a negative electrode, was adsorbed was assembled. When assembling the positive electrode, the conductive surface of the positive electrode and the negative electrode was brought into the battery so that the polymer electrolyte coating layer and the titanium dioxide layer on which the dye was adsorbed face each other. At this time, leave about 60 microns-thick polymer made of SURLYN (manufactured by Du Pont) between the anode and the cathode, and leave a space for injecting the liquid electrolyte, and fix it with a clip and put it in a 130 ℃ oven for 1 to 2 minutes. The electrode was brought into close contact.

An electrolyte was then prepared. 0.1M LiI, 0.05MI _2, 0.3M DMPII, 0.5M 2- (dimethylamino) -pyridine, 0.5M 5-chloro-1-ethyl-2-methylimidazole, 3 ml of ethylene carbonate and 7 ml of gamma butyrolactone The liquid electrolyte was prepared by addition to the solution. A liquid electrolyte was injected and sealed between the assembled positive electrodes to complete a dye-sensitized solar cell.

Comparative Example 1

Except for the addition of erbium (III) nitrate (Er (NO ₃ ) ₃ ) and ytterbium (III) nitrate (Yb (NO ₃ ) ₃ ) when preparing the powder for use in the scattering layer in Example 1 The same process as in Example 1 to prepare a scattering layer slurry of interest and to prepare a dye-sensitized solar cell coated with the scattering layer.

Comparative Example 2

Except that in Example 1, except that the titanium dioxide layer is coated only once without the scattering layer slurry on the transparent conductive substrate (TCO) is coated with fluorine tin oxide (FTO) in Example 1 The same process was performed to complete the desired dye-sensitized solar cell.

Test Example

In order to evaluate the light conversion efficiency of the dye-sensitized solar cells prepared in Examples and Comparative Examples, the photovoltaic characteristics were measured by measuring the photovoltage and the photocurrent as follows, and the current density (Isc) and the voltage obtained therefrom were measured. Using the (Voc) and the fill factor (ff), the light conversion efficiency (ηe) was calculated according to 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.

ηe = (Voc × Isc × ff) / (Pine)

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

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

division Current density (mA) Voltage (V) Fill factor Optical conversion efficiency (%) Example 1 18.9 0.773 0.615 8.98 Comparative Example 1 18.4 0.773 0.614 8.72 Comparative Example 2 17.1 0.743 0.613 7.80

As shown in Table 1, the dye-sensitized solar cell including the scattering layer formed using the titanium dioxide powder doped with Er ³⁺ and Yb ³⁺ of Example 1 according to the present invention is Er ³⁺ Compared with the dye-sensitized solar cell (Comparative Example 1) in which the scattering layer was formed using titanium dioxide powder which is not doped with Yb ³⁺ and the fuel-sensitized solar cell (Comparative Example 2) which did not form the scattering layer. It was confirmed that the density was higher and the light conversion efficiency was improved. In addition, it was confirmed that the voltage was also improved compared to the conventional fuel-sensitized solar cell.

4 is a scanning electron micrograph of the titanium dioxide powder prepared according to Example 1 of the present invention, Figure 5 is an X-ray diffraction pattern of the titanium dioxide powder prepared according to Example 1 of the present invention. The scanning electron microscope photograph of FIG. 4 showed that the powder forming the embossed surface was synthesized, and the amorphous powder was synthesized through the X-ray diffraction pattern.

1 is a cross-sectional view of a general dye-sensitized solar cell.

2 is a process flowchart of a method of preparing titanium dioxide powder doped with Er ³⁺ and Yb ³⁺ according to an embodiment of the present invention.

3 is a cross-sectional view of a dye-sensitized solar cell according to an embodiment of the present invention.

4 is a scanning electron micrograph of the titanium dioxide powder prepared according to Example 1 of the present invention.

5 is an X-ray diffraction pattern of the titanium dioxide powder prepared according to Example 1 of the present invention.

Explanation of symbols on the main parts of the drawings

100: negative electrode 110, 210: transparent substrate

120, 220: transparent conductive oxide layer 130: nano oxide layer

200: positive electrode 230: platinum layer

300: electrolyte 400: thermoplastic polymer layer

500: scattering layer

Claims (12)

(S1) A mixture is prepared by mixing titanium isopropoxide, erbium (III) nitrate (Er (NO ₃ ) ₃ ), ytterbium (III) nitrate (Yb (NO ₃ ) ₃ ) and carbon black in a solvent. step; (S2) stirring to add water to the mixture to form a gel; (S3) drying the gel to prepare a precursor; And (S4) A method for preparing titanium dioxide powder doped with Er ³⁺ and Yb ³⁺ comprising the step of heat-treating the precursor. The method of claim 1, The solvent is a method of producing a titanium dioxide powder doped with Er ³⁺ and Yb ³⁺ , characterized in that the mixed solvent containing acetic acid and ethanol. The method of claim 2, The content of acetic acid and ethanol in the mixed solvent is 1 to 20% by volume, 80 to 99% by volume based on the total volume of the mixed solvent, the method for producing the titanium dioxide powder doped with Er ³⁺ and Yb ³⁺ , respectively . The method of claim 1, Method for producing titanium dioxide powder doped with Er ³⁺ and Yb ³⁺ , characterized in that the heat treatment temperature 600 ~ 800 ℃ in the step (S4). The method of claim 1, Method for producing titanium dioxide powder doped with Er ³⁺ and Yb ³⁺ , characterized in that the drying temperature in the step (S3) 100 ~ 130 ℃. The method of claim 1, In the mixture, the erbium (III) nitrate (Er (NO ₃ ) ₃ ) and ytterbium (III) nitrate (Yb (NO ₃ ) ₃ ) are 5-20 mol% based on the number of moles of titanium isopropoxide, respectively. Added, The carbon black is a method for producing titanium dioxide doped with Er ³⁺ and Yb ³⁺ , characterized in that 10 to 200 parts by weight relative to 100 parts by weight of the titanium isopropoxide. The method of claim 1, The carbon black is a method for producing titanium dioxide powder doped with Er ³⁺ and Yb ³⁺ , characterized in that any one or more selected from the group consisting of acetylene black, furnace black and super P. (A) a transparent substrate; A transparent conductive oxide layer formed on the transparent substrate; And a negative electrode formed on the transparent conductive oxide layer and including a nano oxide layer to which dye is adsorbed; (B) a transparent substrate; A transparent conductive oxide layer formed on the transparent substrate; And a platinum layer formed on the transparent conductive oxide layer. (C) a scattering layer formed on the nano-oxide layer of the negative electrode, comprising a titanium dioxide powder doped with Er ³⁺ and Yb ³⁺ ; And (D) a dye-sensitized solar cell, comprising an electrolyte interposed between the negative electrode and the positive electrode. The method of claim 8, The transparent conductive oxide layer included in the negative electrode and the positive electrode is a dye-sensitized solar cell, characterized in that the layer comprising a fluorine-doped indium tin oxide or indium tin oxide. The method of claim 8, The nano oxide layer is a dye-sensitized solar cell, characterized in that the layer comprising one or more selected from the group consisting of titanium dioxide, tin dioxide and zinc oxide. The method of claim 8, The dye adsorbed on the nano oxide layer is one selected from the group consisting of ruthenium complex, xanthine dye, cyanine dye, basic dye, porphyrin compound, azo dye, phthalocyanine compound, anthraquinone dye and polycyclic quinone dye. Dye-sensitized solar cell characterized by the above. The method of claim 8, The electrolyte is a dye-sensitized solar cell, characterized in that consisting of a pair of iodide and triiode.

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