KR20140115406A - Method of preparing zinc oxide nanorod composite, zinc oxide nanorod composite prepared from the same, and dye sensitized solar cell including the zinc oxide nanorod composite - Google Patents

Abstract

Provided are a method for manufacturing a zinc oxide nanorod composite which comprises the steps of: manufacturing a precursor solution including an oxide precursor; soaking a substrate having a zinc oxide nanorod mounted in the precursor solution; and applying ultrasound to the precursor solution in which a substrate having the zinc oxide nanorod grown is soaked in to grow an oxide nanolayer on the surface of the zinc oxide nanorod, a zinc oxide nanorod composite manufactured by the same, and a dye sensitized solar cell including the same.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a zinc oxide nanorod composite material, a zinc oxide nanorod composite material, and a dye-sensitized solar cell including the zinc oxide nanorod composite material. THE ZINC OXIDE NANOROD COMPOSITE}

The present invention relates to a method for producing a zinc oxide nanorod composite, a zinc oxide nanorod composite made therefrom, and a dye-sensitized solar cell comprising the zinc oxide nanorod composite.

The dye-sensitized solar cell (DSSC) has received great attention due to its low manufacturing cost and high energy conversion efficiency. Zinc oxide (ZnO) is an important material in the structure of a dye-sensitized solar cell and is used as an electron transport layer.

Zinc oxide (ZnO) has a band structure similar to that of titanium dioxide (TiO ₂ ), and its electron mobility is 10 ⁷ times larger than that of TiO ₂ . The structure of the conventional TiO ₂ has been using nano-sized spherical particles, which have a large specific surface area per unit area, which increases the space for adsorbing the dye, but occurs when the electrons injected from the dye move through the spherical particles The interface acts as a resistor, leading to a reduction in efficiency. Various structures have been studied to solve this problem, but TiO ₂ has shown limitations in structural modification.

On the other hand, zinc oxide can be grown to various nanostructures such as nanorods, nanotetrapheres, and nanosheets, and it is under study to increase the performance of cells by reducing resistance due to electron transport in the operation of dye-sensitized solar cells .

One embodiment of the present invention is to provide a method for manufacturing a zinc oxide nanorod composite.

Another embodiment of the present invention is to provide a zinc oxide nanorod composite made from the zinc oxide nanorod composite.

Another embodiment of the present invention is to provide a dye-sensitized solar cell including the zinc oxide nanodevice composite material with improved operational efficiency and performance.

Another embodiment of the present invention is to provide a method of manufacturing the dye-sensitized solar cell.

One embodiment of the present invention is directed to a method of preparing a precursor solution comprising: preparing a precursor solution comprising an oxide precursor; Immersing a substrate on which a zinc oxide nanorod is grown in the precursor solution; And applying ultrasonic waves to the precursor solution containing the substrate on which the zinc oxide nanorods are grown to grow an oxide nanorods on the surface of the zinc oxide nanorods.

The oxide precursor may include titanium tetrachloride, zinc acetate, cobalt acetate, copper (II) acetate, or combinations thereof.

The precursor solution may be an aqueous solution containing the oxide precursor at a concentration of 0.05 to 0.1 M.

The ultrasonic waves may be performed at a power of 700 to 800 W, at a frequency of 10 to 30 kHz, and may be performed at an amplitude of 30 to 50%.

The step of applying ultrasonic waves may be performed by keeping the precursor solution at room temperature, and may be performed for 10 to 40 minutes.

The method may further include the step of growing an oxide nanorod on the surface of the zinc oxide nanorod, and then firing the zinc oxide nanorod, on which the oxide nanorod is grown, RTI ID = 0.0 > 30 minutes < / RTI > to 1 hour.

Another embodiment of the present invention provides a zinc oxide nanorod composite comprising the zinc oxide nanorod and an oxide nanorod located on the surface of the zinc oxide nanorod, the zinc oxide nanorod composite being manufactured by the method of manufacturing the zinc oxide nanorod composite .

The zinc oxide nanorods may have a width of 30 to 200 nm and a length of 3 to 10 [mu] m.

The zinc oxide nanorods may have a non-oriented or vertical orientation.

The zinc oxide nanorods may be single crystals.

The oxide nano-layer may be at least one selected from the group consisting of Co, Cu, Ti, Zr, Sr, Zn, In, Yr, La, V, Mo, W, Sn, Nb, Mg, Al, Y, Sc, Sm, Ga, ≪ / RTI > or combinations thereof.

The oxide nano-layer may have a thickness of 3 to 30 nm.

The oxide nano-layer may have no orientation.

According to another embodiment of the present invention, there is provided a liquid crystal display comprising: a first electrode through which sunlight is incident and transmitted; A second electrode arranged to face the first electrode; A photoactive layer positioned between the first electrode and the second electrode; And an electrolyte filled between the photoactive layer and the second electrode, wherein the photoactive layer comprises a dye sensitized solar cell comprising a photo sensitive dye adsorbed on a surface of the zinc oxide nanostructure matrix composite and the zinc oxide nanostructure matrix composite, Lt; / RTI >

The photoactive layer may have a thickness of 3 to 10 [mu] m.

According to another embodiment of the present invention, there is provided a method of manufacturing a display device, comprising: forming a conductive layer on a transparent substrate, the conductive layer including a conductive material to form a first electrode; Growing a zinc oxide nanorod on the first electrode using an ultrasonic chemical growth method; Forming an oxide nanorod layer on the surface of the zinc oxide nanorod using an ultrasonic chemical growth method to form a zinc oxide nanorod composite; Forming a photoactive layer by adsorbing a photosensitive dye on the zinc oxide nanorod composite; And forming a second electrode to cover the photoactive layer, and then injecting an electrolyte into the dye-sensitized solar cell.

Other details of the embodiments of the present invention are included in the following detailed description.

A dye-sensitized solar cell having improved operating efficiency and performance can be realized.

1 is a schematic diagram of an ultrasonic generator for surface coating of zinc oxide nanorods according to one embodiment.
2 is a cross-sectional view schematically showing the structure of a dye-sensitized solar cell according to one embodiment.
FIG. 3 is a schematic view showing the effect of an oxide nanolayer coated on the surface of a zinc oxide nanorods on the behavior of electrons generated by incident light in a dye-sensitized solar cell according to an embodiment.

Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited thereto, and the present invention is only defined by the scope of the following claims.

As used herein, unless otherwise defined, "nano" refers to the nanoscale size and specifically refers to a size of less than 1 micron.

A dye-sensitized solar cell (DSSC) may include a first electrode, a second electrode, and a photoactive layer interposed between the first electrode and the second electrode.

When zinc oxide nanorods are used as the photoactive layer, defects exist in the surface between the zinc oxide and the dye contained in the photoactive layer, which limits the efficiency of the dye-sensitized solar cell.

According to one embodiment, the surface of the zinc oxide nanorods is coated with a nano-sized oxide to reduce the defect state present on the surface with the dye, and the electrons injected into the photoactive layer migrate back to the dye or electrolyte a recombination phenomenon is reduced and a structure for increasing the efficiency of photoelectrons is proposed.

The dipping method using a dip coater is mainly used by the surface coating method of the zinc oxide nanorods. In the case of such a dipping method, it takes much time to immerse the dipping method, and the elevation rate of the dip coater and the molar concentration of the precursor are optimized There are difficulties in adjusting.

According to one embodiment, a sonochemistry growth method useful for the production of a large-area dye-sensitized solar cell can be used.

In one embodiment, there is provided a process for preparing a zinc oxide nanorod composite in which an oxide nanorod is positioned on the surface of the zinc oxide nanorod. In other words, a method of coating the surface of the zinc oxide nanorods with the oxide nanorods, that is, a method of growing the oxide nanorods on the surface of the zinc oxide nanorods is as follows.

 Preparing a precursor solution containing an oxide precursor, immersing the substrate on which the zinc oxide nanorods are grown in the precursor solution, and applying ultrasonic waves to the precursor solution containing the zinc oxide nanorods grown thereon A zinc oxide nanorod composite can be prepared by growing an oxide nanorod on the surface of the zinc oxide nanorod.

The precursor solution may be prepared by dissolving the oxide precursor in a solvent. And may be stirred for efficient dispersion of the precursor solution.

The oxide precursor may be titanium tetrachloride, zinc acetate, cobalt acetate, copper (II) acetate or a combination thereof.

As the solvent, water may be used. Specifically, the water serves as a dispersion medium of the oxide precursor and also serves as a mother liquor in which oxide nano-layers formed on the surface of the zinc oxide nanorods grow. Therefore, impurities that can affect the coating Removed purified water, more specifically deionized water, can be used.

The precursor solution may contain the oxide precursor at a concentration of 0.03 to 0.1 M, specifically at a concentration of 0.05 to 0.07 M. When the concentration of the oxide precursor is within the above range, the thickness of the oxide nano-layer formed on the surface of the zinc oxide nanorod can be adjusted to an appropriate range. When the thickness of the oxide nano-layer is obtained in an appropriate range, a maximum effect can be obtained as a light-absorbing surface coating material in a dye-sensitized solar cell.

The thickness of the oxide nanolayer may be, for example, 3 to 30 nm, and more specifically 15 to 30 nm. When the thickness of the oxide nano-layer is within the above range, a maximum effect can be obtained as a light-absorbing surface coating material in a dye-sensitized solar cell.

After the substrate on which the zinc oxide nanorods are grown is immersed in the prepared precursor solution, ultrasound can be applied. This step can be explained with reference to Fig.

1 is a schematic diagram of an ultrasonic generator for surface coating of zinc oxide nanorods according to one embodiment.

1, the ultrasonic generator 10 may include a substrate 10, a precursor solution 2, an ultrasonic probe 3, and a stirrer 4. Specifically, after the Teflon mold having the substrate 1 fixed thereon was inserted into a container containing the stirred precursor solution 2 using the stirrer 4, the ultrasonic probe 3 was inserted into the hole at the center of the container And ultrasonic waves are applied.

The substrate 1 may comprise dried zinc oxide nanorods.

The substrate 1 is not particularly limited, and a silicon wafer substrate, a glass substrate, a polymer substrate, or the like can be used as a specific example.

The process of applying the ultrasonic waves may be performed under conditions of, for example, a power of 700 to 800 W and a frequency of 10 to 30 kHz. Further, the ultrasonic wave can be applied under the condition that the amplitude is 30 to 50%. When the amplitude of the ultrasonic wave is within the above range, it is easy to control the coating speed and the coating condition of the oxide nano-layer. More specifically, ultrasonic waves can be applied under the conditions of power 730 to 770 W, frequency 15 to 25 kHz, and amplitude 35 to 45%.

Also, since the temperature of the ultrasonic probe 3 and the size of the ultrasonic probe 3 may affect the production of the oxide nanocrystal, the temperature and the size can be appropriately selected.

According to one embodiment, the step of applying ultrasonic waves may be performed by maintaining the temperature of the precursor solution at room temperature. It is possible to raise the temperature to a certain temperature or higher due to the generation of hot spots in the solution generated upon application of ultrasonic waves and the generated energy from the hot spots. However, this temperature rise is a negligible change from the viewpoint of controlling the parameters of the surface coating due to ultrasonic growth. In other words, it is possible to coat without adjusting the temperature when applying ultrasonic waves.

The step of applying ultrasonic waves may be performed for 10 to 40 minutes, and specifically for 20 to 40 minutes. When the ultrasound is immersed for the above-mentioned time, the thickness of the oxide nano-layer is appropriately formed to obtain the maximum effect as the light-absorbing surface coating material in the dye-sensitized solar cell.

As a result of the application of the ultrasonic waves, an oxide layer may be formed on the surface of the zinc oxide nanorods without using a catalyst for the formation and growth of the oxide nanorods to grow into a nano-sized layer.

The method of growing the oxide nanocrystal on the surface of the zinc oxide nanorods by applying the ultrasonic waves can use a cavitation effect generated when ultrasonic waves are applied to the liquid.

Specifically, cavitation is formed by repetitive processes of compression and expansion of a liquid phase when an ultrasonic wave passes through a liquid phase, and grows under the influence of a negative pressure upon expansion. When cavitation reaches a critical value in a compression process, do. The process of cavitation formation, growth and collapse by ultrasound is called the cavitation effect. When the micro-bubble collapses due to such a joint effect, a high temperature of about 5,000 K and a high pressure of about 200 bar are instantaneously generated. Such high temperature and high pressure cause the decomposition of the oxide precursor, The oxide cations generated in the reaction are reacted with oxygen (O) present in water to form oxides and grow in the form of nano-layers through continuous reaction. At this time, the whole system is maintained at room temperature and normal pressure.

As described above, a high-quality oxide nano-layer can be evenly coated on the surface of a large number of zinc oxide nanorods within a short synthesis time of about 40 minutes at normal temperature and atmospheric pressure, and this can be applied to a large area without restriction of the substrate .

After the ultrasonic wave is applied, the step of firing the zinc oxide nanorods having the oxide nanorods grown on the surface thereof may be further performed.

The firing process may be performed at a temperature of 70 to 500 ° C, and more specifically, at a temperature of 400 to 500 ° C. The firing process may be performed for 30 minutes to 1 hour. When the firing process is performed within the temperature and time range, a zinc oxide nanorod composite free of impurities and moisture can be produced.

The zinc oxide nanorod composite obtained by growing the oxide nanorods on the surface of the zinc oxide nanorods in this manner has no change in transmittance with respect to visible light. In addition, when the zinc oxide nanodoblock composite is used as a light absorbing material in a dye-sensitized solar cell, the recombination phenomenon of electrons injected from the dye is reduced, thereby enabling efficient use of electrons generated by the sunlight.

According to another embodiment of the present invention, there is provided a zinc oxide nanorod composite made by the method of manufacturing the zinc oxide nanorod composite.

The zinc oxide nanorod composite comprises a zinc oxide nanorod and an oxide nanorod located on the surface of the zinc oxide nanorod.

The zinc oxide nanorods have a width and a length, and a ratio of the length to the width is referred to as an aspect ratio. The long length ratio is proportional to the specific surface area of the zinc oxide nanorods. Specifically, when the long length is small, the zinc oxide nanorods have a small specific surface area. If the long length is large, Which means that the surface area is large.

Specifically, the zinc oxide nanorods may have a width of 30 to 200 nm and a length of 3 to 10 탆, more specifically, a width of 50 to 100 nm and a length of 5 to 10 탆. When the zinc oxide nanorods have a width and a length within the above range, the efficiency of the photoactive layer in the dye-sensitized solar cell can be increased as the current increases, and the vertical orientation can be maintained, The production efficiency can be improved.

The zinc oxide nanorods may have a non-oriented or vertical orientation, and of these, preferably, they may have a vertical orientation. Vertically oriented zinc oxide nanorods adsorb more dyes and increase the mean free path of electrons generated from the photosensitive dye.

The zinc oxide nanorods may be single crystals. The zinc oxide has a hexagonal structure crystallographically and has a material characteristic favorable for manufacturing nanorods. In addition, a single crystalline nanorod can be prepared which is well aligned with other inorganic oxides such as TiO ₂ and SnO _2, and thus can be usefully used in a dye-sensitized solar cell.

The oxide nano-layer coated on the surface of the zinc oxide nanorods may include at least one of Co, Cu, Ti, Zr, Sr, Zn, In, Yr, La, V, Mo, W, Sn, Nb, Mg, , Sm, Ga, In, TiSr, or a combination of these metals, but is not limited thereto. Of these, TiO ₂ , SnO ₂ , ZnO, CoO, CuO ₂ , Nb ₂ O ₅ , TiSrO ₃ or a combination thereof can be preferably used. Of these, TiO ₂ , ZnO, CoO, CuO ₂ , Combinations can be used.

The oxide nano-layer may have a thickness of 3 to 30 nm, more specifically 15 to 30 nm, and more specifically 15 to 25 nm. When the oxide nano-layer is coated to a thickness within the above-mentioned range, it is easy to inject and transport photoelectrons when used as a light absorbing material in a dye-sensitized solar cell, thereby minimizing the recombination phenomenon. . In addition, the decrease of the surface area due to the oxide nano-layer can be reduced so that the photosensitive dye adsorbed on the oxide nano-layer absorbs more light.

The thickness of the oxide nano-layer can be measured by X-ray photoelectron spectroscopy (XPS) analysis and transmission electron microscopy (TEM).

Also, the bonding structure of the oxide nanocrystal can be analyzed through the XPS analysis and the TEM measurement. As a result of the analysis, it can be seen that the bonding structure of the oxide nano-layer is not largely changed as compared with before coating.

The oxide nanocrystal may also be nano-sized amorphous or crystalline and exhibit high visible light transmittance. When the oxide nano-layer has a relatively large thickness, it may have the crystalline structure. When the oxide nano-layer has a relatively small thickness, the oxide nano-layer may have the amorphous structure.

The oxide nano-layer may have no orientation. Specifically, the orientation of crystalline or amorphous oxides can be distributed randomly.

According to another embodiment, there is provided a dye-sensitized solar cell comprising the zinc oxide nanorod composite.

The dye-sensitized solar cell will be described with reference to FIG.

2 is a cross-sectional view schematically showing the structure of a dye-sensitized solar cell according to one embodiment.

Referring to FIG. 2, the dye-sensitized solar cell 100 includes a first electrode 110 through which solar light is incident and transmitted, a second electrode 120 disposed to face the first electrode 110, A photoactive layer 130 positioned between the first electrode 110 and the second electrode 120 and an electrolyte 140 filled between the photoactive layer 130 and the second electrode 120 have. Here, the first electrode may be referred to as a semiconductor electrode, and the second electrode may be referred to as a counter electrode.

The first electrode 110 is an electrode through which sunlight is incident and transmitted, and includes a transparent substrate and a conductive layer formed on the transparent substrate.

The transparent substrate may be any material having transparency so that external light can be incident thereon. Specific examples thereof include plastics such as polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polypropylene, polyimide, triacetylcellulose, and copolymers thereof; Or glass.

The transparent substrate may be doped with a material selected from the group consisting of Ti, In, Ga and Al.

The conductive layer may include at least one of indium tin oxide (ITO), fluorine tin oxide (FTO), ZnO- (Ga ₂ O ₃ or Al ₂ O ₃ ), tin oxide, antimony tin oxide tin oxide (ATO), zinc oxide, or a combination thereof. Among these, SnO ₂ excellent in conductivity, transparency and heat resistance or ITO inexpensive in cost can be included. The conductive layer may be formed of a single layer or a multi-layered film of the conductive metal oxide.

The second electrode 120 may include a transparent substrate and an electrode layer formed on the transparent substrate to be opposed to the first electrode. The electrode layer may include a transparent electrode and a catalyst electrode (not shown).

 The transparent substrate may be made of glass or plastic as in the first electrode.

The transparent electrode formed over the transparent substrate is indium tin oxide, fluorine tin oxide, antimony tin oxide, zinc oxide, tin _{oxide, ZnO-Ga 2 O 3,} ZnO-Al 2 O 3 And the like. At this time, the transparent electrode may be a single layer or a multi-layered film of the transparent material.

Also, irregularities may be formed on the surface of the transparent electrode to increase the light scattering effect. The irregularities may have a stair shape, a needle shape, a mesh shape, a scratch shape, and a scar shape.

The catalytic electrode serves to activate a redox couple, and may include a conductive material such as Pt, Au, Ru, WO ₃ , TiO _2, and a conductive polymer.

The electrolyte 140 is impregnated into the space between the first electrode 110 and the second electrode 120 and the impregnated electrolyte 140 is injected into the space between the zinc oxide nanodoblock composites in the photoactive layer 130 It can be uniformly dispersed even into the formed pores.

The electrolyte 140 may be a liquid electrolyte or a solid electrolyte.

The electrolyte solution is an iodide / triodide pair, which receives electrons from the second electrode 120 by redox reaction and transfers the electrons to molecules of the photosensitive dye.

As the electrolyte solution, a solution in which iodine is dissolved in acetonitrile may be used. However, the electrolyte solution is not limited thereto, and any solution may be used as long as it has a hole conduction function.

The photoactive layer 130 may include a photoelectrode layer (not shown) including a photo sensitive dye (not shown) adsorbed on the zinc oxide nanorod composite and the zinc oxide nanorod composite.

The zinc oxide nanorod composite includes a zinc oxide nanorod 130b and an oxide nanorod 130a located on the surface of the zinc oxide nanorod 130b.

The zinc oxide nanorods 130b are grown from the first substrate 110 by using an ultrasonic chemical growth method. The zinc oxide nanorods 130b receive electrons generated from the photosensitive dye, The mean free path of the device is so large that it minimizes the current loss of the device.

The photosensitizing dye is adsorbed on the surface of the zinc oxide nanorod bar composite material, and specifically adsorbed on the surface of the oxide nanolayer 130a to absorb visible light to generate excited electrons.

The light-sensitive dye may be a metal complex including Al, Pt, Pd, Eu, Pb, Ir, Ru, and the like. The Ru can form many organometallic complexes as an element belonging to the platinum group, and a dye containing Ru is generally used in many cases. For example, Ru (etc bpy) ₂ (NCS) ₂ .2CH ₃ CN type is widely used. Here, etc are (COOEt) ₂ or (COOH) ₂ and reactable with the surface of a porous film (for example, TiO ₂ ).

The above-mentioned photosensitive dye may be a dye containing an organic dye or the like. The organic coloring matters include coumarin, porphyrin, xanthene, riboflavin, triphenylmethan, and the like. These can be used alone or in combination with the Ru complex to improve the photoelectric conversion efficiency by improving absorption of visible light of a long wavelength.

The photoelectrode layer may include pores along a gap between the zinc oxide nanorod composites.

FIG. 3 is a schematic view showing the effect of an oxide nanolayer coated on the surface of a zinc oxide nanorods on the behavior of electrons generated by incident light in a dye-sensitized solar cell according to an embodiment.

Referring to FIG. 3, the dye-sensitized solar cell 200 includes a first electrode 210 and a photoactive layer 230 formed on the first electrode 210.

At this time, the electric current I _I injected into the zinc oxide nanorods 230b generated by the light transmitted through the photoactive layer 230 in response to the dye, the electrons already injected are recombined with the holes of the photosensitive dye The current I _R generated by the recombination, and the short-circuit current I _SC of the dye-sensitized solar cell have the relationship expressed by the following equation (1).

[Equation 1]

I _SC = I _I - I _R

In Equation (1), the I _I value can be obtained using an ultraviolet-visible spectroscopy (UV-VIS spectroscopy) measurement. As a result, by measuring the short-circuit current (I _SC ) of the dye-sensitized solar cell, the behavior of electrons due to recombination occurring in the oxide nanorods coated on the surface of the zinc oxide nanorods can be analyzed. At this time, the recombination phenomenon can be minimized through the coating thickness of the oxide nano-layer. In other words, when the thickness of the oxide nano-layer is 3 to 30 nm, the remnant of the combination of the photosensitive dye and the zinc is small, so that the recombination phenomenon can be reduced and the performance of the device can be improved.

In addition, the oxide nano-layer may have an appropriate surface coverage, and specifically, it may have a structure coated with a certain thickness as shown in FIG. The surface compensation degree is a numerical value indicating the extent to which the oxide nanorods are coated on the surface of the zinc oxide nanorods. The surface compensation index is a value of the specific surface area of the coated zinc oxide nanorods versus the specific surface area of the zinc oxide nanorods Ratio.

The photoactive layer may have a thickness of 3 to 10 mu m, and more specifically, may have a thickness of 6 to 9 mu m. When the thickness of the photoactive layer is within the above range, the optimum dye adsorption ability and surface coating effect can be seen.

The dye-sensitized solar cell can be produced by the following method.

Forming a first electrode by forming a conductive layer including a conductive material on a transparent substrate, growing zinc oxide nanorods on the first electrode using ultrasonic chemical growth, forming a surface of the zinc oxide nanorods Forming a zinc oxide nanorod composite by growing an oxide nanorod using an ultrasonic chemical growth method; forming a photoactive layer by adsorbing the photoactive dye on the zinc oxide nanorod composite; And then injecting an electrolyte after forming the second electrode.

The first electrode is the same as that described above, and the manufacturing method thereof can be manufactured according to a usual manufacturing method. For example, the first electrode may be formed by forming a conductive layer containing a conductive material on a transparent substrate using a physical vapor deposition (PVD) method such as electrolytic plating, sputtering, or electron beam evaporation.

A composition for forming zinc oxide nanorods prepared by dispersing zinc oxide nanoparticles and optionally a binder in a solvent on the first electrode is coated and then heat treated or mechanically necked to form zinc oxide nanorods.

The binder may be at least one selected from the group consisting of polyvinylidene fluoride, polyhexafluoropropylene-polyvinylidene fluoride copolymer, polyvinyl chloride, polyvinyl pyridine and styrene-butadiene rubber.

Examples of the solvent include alcohols such as ethanol, isopropyl alcohol, n-propyl alcohol and butyl alcohol, water, dimethyl sulfoxide and N-methyl pyrrolidone.

The step of growing the zinc oxide nanorods on the first electrode may be performed by a vapor deposition method, a hydrothermal synthesis method, a laser ablation method, an electrophoresis method, an ultrasonic chemical growth method, or a combination thereof depending on the kind of the composition. But is not limited thereto. Among them, the ultrasonic chemical growth method which is effective in growth temperature and time can be used.

The zinc oxide nanorods grown on the first electrode are subjected to heat treatment or drying.

The heat treatment may be carried out at 400 to 500 占 폚 for 10 to 60 minutes, and the drying may be carried out at a temperature of 100 占 폚 or less.

Next, the oxide nanorods are coated on the surface of the zinc oxide nanorods by ultrasonic chemical growth to form a zinc oxide nanorod composite.

Next, the zinc oxide nanodoblock composite having the surface of the zinc oxide nanorods coated with the oxide nanorods is sprayed, coated or immersed with a dispersion containing the photosensitive nanoparticles to adsorb the photosensitive nanoparticles to the zinc oxide nanorod composite .

For example, in the case of immersion, the first electrode on which the zinc oxide nanorod composite is grown is immersed in the dispersion containing the photo-sensitive dye for 3 to 12 hours to naturally adsorb the photo-sensitive dye, The adsorption time can be greatly reduced by heating to 90 ° C.

As the photosensitive dye, there may be used the same ones as described above. The solvent for dispersing the photosensitive dye is not particularly limited, but acetonitrile, dichloromethane, alcohol solvents and the like can be used. Examples of the alcohol-based solvent include ethanol, t-butyl alcohol, and the like.

The dispersion containing the photosensitive dye may further include organic pigments of various colors to improve the efficiency of absorbing visible light of a long wavelength.

After the dye is adsorbed, the photoactive layer may be prepared as a single layer by washing with a solvent or the like.

Subsequently, a second electrode is separately prepared, and then the light-sensitive dye is bonded to the adsorbed first electrode.

The second electrode includes a transparent substrate, a transparent electrode, and a catalyst electrode as described above, and the second electrode having the above structure can be manufactured by a conventional manufacturing method.

The catalyst electrode may be formed by applying a catalyst precursor solution dissolved in an organic solvent such as alcohol or the like, for example, a H ₂ PtCl ₆ solution on the transparent electrode, followed by a high-temperature heat treatment at 400 ° C or higher in an air or oxygen atmosphere, Electroplating, or physical vapor deposition (PVD) such as sputtering, electron beam evaporation, or the like.

The bonding of the first electrode having the photoactive layer and the second electrode may be performed by a conventional method. Specifically, adhesives such as a thermoplastic polymer film, an epoxy resin, or an ultraviolet (UV) curing agent; Or they can be bonded to each other by welding or welding by ultrasonic waves, heat, infrared rays, vibration, or the like. When the thermoplastic polymer film is used, the thermoplastic polymer film is placed between two electrodes, and is then thermally compressed and sealed. When the epoxy resin or ultraviolet (UV) curing agent is used, the first and second electrodes Respectively.

Then, a fine hole passing through the second electrode is formed, and an electrolyte is injected into the space between the two electrodes through the hole to manufacture a dye-sensitized solar cell.

The electrolyte is the same as that described above, and the electrolyte may be injected by a conventional method.

According to the method for manufacturing a dye-sensitized solar cell, the oxide nano-layer can be directly formed and grown on the surface of the zinc oxide nanorod without using any catalyst. Further, the oxide nano-layer can be shortened compared with the conventional manufacturing time due to the use of ultrasonic energy, and the oxide nano-layer can maintain excellent stability since it does not affect the photo-electrode layer.

The reduction of the recombination phenomenon due to the surface coating layer of the zinc oxide nanorods increases the short circuit photocurrent density (J _SC ) of the dye-sensitized solar cell to ultimately increase the energy conversion efficiency.

Hereinafter, specific embodiments of the present invention will be described. However, the embodiments described below are only intended to illustrate or explain the present invention, and thus the present invention should not be limited thereto.

Example  One

(1) 4 g of zinc acetate dehydrate (ZAD) powder was mixed with 700 ml of deionized water in a 1000 ml container to dissolve, and the temperature was raised to 90 ° C. Subsequently, a fluorine-tin oxide (FTO) glass substrate (TEC ^TM -8, Pilkington TEC Glass) was immersed in a container containing the mixed solution, and an ultrasonic probe was inserted into the hole at the center of the container. Ultrasonic energy was applied for 1 hour To grow zinc oxide nanorods. The width and length of the formed zinc oxide nanorods were 50 nm and 5 탆, respectively, and showed a vertical orientation on the FTO glass substrate.

A titanium tetrachloride (TiCl ₄₎ was dissolved in a mixture containing 200ml of deionized water and in a 1000ml vessel to prepare a TiO ₂ precursor solution. Next, the Teflon mold having the FTO glass substrate on which the zinc oxide nanorods are grown is inserted into a container containing the precursor solution, an ultrasonic probe is inserted into the hole at the center of the container, ultrasonic energy is applied, An oxide nanostructure was grown on the surface of the zinc nanorod. The applied voltage was 750 W, the frequency was 20 kHz, and the amplitude was 40%.

The zinc oxide nanorods on which the oxide nanorods were grown were fired at 400 ° C for 30 minutes to prepare oxide nanorods, that is, zinc oxide nanorod composites coated on the surface of the zinc oxide nanorods. At this time, the thickness of the oxide nano-layer was 20 nm.

(2) The FTO glass substrate on which the zinc oxide nanorod composite was formed, that is, the first electrode, was placed in a dispersion in which N719 dye (DYESOL) was dispersed in a mixed solvent of ethanol and t-butyl alcohol, So that the dye was adsorbed to form a photoactive layer.

Then, a transparent electrode made of tin oxide and a catalyst electrode made of platinum were formed on a transparent substrate made of polyethylene terephthalate to prepare a second electrode.

Then, a dye-sensitized solar cell was prepared by bonding an iodoly type electrolyte (AN-50 ™, Solaronix) to the first electrode and the second electrode having the photoactive layer formed thereon.

Example  2

Except that the ZnO precursor solution was prepared using zinc acetate (Zn (O ₂ CCH ₃ ) ₂ ) instead of the TiO ₂ precursor solution prepared by using titanium tetrachloride (TiCl ₄ ) in Example 1 A dye-sensitized solar cell was prepared in the same manner as in Example 1.

Example  3

Except that the CoO precursor solution was prepared using cobalt acetate (Co (CH ₃ COO) ₂ ) instead of the TiO ₂ precursor solution prepared by using titanium tetrachloride (TiCl ₄ ) in Example 1, 1, a dye-sensitized solar cell was prepared.

Example  4

Except that the CuO ₂ precursor solution was prepared using copper (II) acetate (Cu (CO ₂ CH ₃ ) ₂ ) instead of the TiO ₂ precursor solution prepared by using titanium tetrachloride (TiCl ₄ ) in Example 1 , A dye-sensitized solar cell was prepared in the same manner as in Example 1.

Comparative Example  One

A dye-sensitized solar cell was prepared in the same manner as in Example 1, except that the oxide nanorods were not grown on the surface of the zinc oxide nanorods in Example 1.

Evaluation 1: Measurement of absorbance of dye

The absorbance of the dye for the photoactive layer prepared in Examples 1 to 4 and Comparative Example 1 was measured using a UV-VIS-NIR spectrometer, and the results are shown in Table 1 below.

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Absorbance
(@ 513 nm) 0.662 0.647 0.641 0.643 0.635

As shown in Table 1, in Examples 1 to 4 in which oxide nano-layers were grown on the surface of zinc oxide nanorods by applying ultrasonic waves, the absorbance at a wavelength of 513 nm was increased compared to Comparative Example 1 in which oxide nano- Respectively. From this, it can be seen that the dye adsorption amount of the zinc oxide nanorods coated with the oxide nanorods is increased.

Evaluation 2: Measurement of efficiency of dye-sensitized solar cell

The incident photon to current conversion efficiency (IPCE) and efficiency of the dye-sensitized solar cell prepared in Examples 1 to 4 and Comparative Example 1 were measured by a photoelectrochemical method, (IV) curves were measured to determine the efficiency, and the photocurrent conversion rate of the device according to the incident light wavelength was measured to calculate the IPCE. The results thus obtained are shown in Table 2 below.

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 IPCE (%)
(@ 530 nm) 38.5 ± 0.90 37.8 ± 0.90 36.2 ± 0.90 36.5 ± 0.90 32.3 ± 0.90 IPCE (%)
(@ 630 nm) 15.7 ± 0.70 15.2 ± 0.67 14.5 ± 0.74 14.5 ± 0.73 13.6 ± 0.71 efficiency(%) 2.32 ± 0.1 2.30 ± 0.1 2.24 ± 0.1 2.25 ± 0.1 2.05 ± 0.1

In the case of the dye-sensitized solar cell of Examples 1 to 4 prepared by growing an oxide nano-layer on the surface of zinc oxide nanorods by applying ultrasonic waves through the above Table 2, The conversion efficiency and the efficiency are both excellent.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, Of the right.

1: substrate
2: Precursor solution
3: Ultrasonic probe
4: Stirrer
10: Ultrasonic generator
100, 200: dye-sensitized solar cell
110, 210: a first electrode
120: second electrode
130, 230: photoactive layer
130a, 230a: an oxide nano-layer
130b, and 230b: zinc oxide nanorods
140: electrolyte
240: iodine redox electrolyte
250: Dye

Claims (20)

Preparing a precursor solution comprising an oxide precursor;
Immersing a substrate on which a zinc oxide nanorod is grown in the precursor solution; And
Applying ultrasonic waves to the precursor solution containing the substrate on which the zinc oxide nanorods are grown to grow the oxide nanorods on the surface of the zinc oxide nanorods
≪ / RTI > wherein the zinc oxide nanostructured composite material is a zinc oxide nanostructure.
The method according to claim 1,
Wherein the oxide precursor comprises titanium tetrachloride, zinc acetate, cobalt acetate, copper (II) acetate or a combination thereof.
3. The method of claim 2,
Wherein the precursor solution is an aqueous solution containing the oxide precursor at a concentration of 0.05 to 0.1 M.
The method according to claim 1,
Wherein the ultrasonic wave is performed at a power of 700 to 800 W.
The method according to claim 1,
Wherein the ultrasonic wave is performed at a frequency of 10 to 30 kHz.
The method according to claim 1,
Wherein the ultrasonic wave is performed at an amplitude of 30 to 50%.
The method according to claim 1,
Wherein the step of applying ultrasonic waves is performed by maintaining the precursor solution at room temperature.
The method according to claim 1,
Wherein the step of applying ultrasonic waves is performed for 10 to 40 minutes.
The method according to claim 1,
After the step of growing the oxide nanorods on the surface of the zinc oxide nanorods,
And firing the zinc oxide nanorods having the oxide nanorods grown on the surface thereof.
10. The method of claim 9,
Wherein the calcining step is carried out at a temperature of 70 to 500 DEG C for 30 minutes to 1 hour.
A process for producing a zinc oxide nanorod composite material according to any one of claims 1 to 10,
A zinc oxide nanorod composite comprising a zinc oxide nanorod and an oxide nanorod located on the surface of the zinc oxide nanorod.
12. The method of claim 11,
Wherein the zinc oxide nanorods have a width of 30 to 200 nm and a length of 3 to 10 m.
12. The method of claim 11,
Wherein the zinc oxide nanorods have a non-oriented or vertical orientation.
12. The method of claim 11,
Wherein the zinc oxide nanorod is a single crystal zinc oxide nanorod composite.
12. The method of claim 11,
The oxide nano-layer may be at least one selected from the group consisting of Co, Cu, Ti, Zr, Sr, Zn, In, Yr, La, V, Mo, W, Sn, Nb, Mg, Al, Y, Sc, Sm, Ga, ≪ / RTI > wherein the zinc oxide nanostructure comprises an oxide of a metal.
12. The method of claim 11,
Wherein the oxide nano-layer has a thickness of 3 to 30 nm.
12. The method of claim 11,
Wherein the oxide nano-layer is a non-oriented zinc nano-nanobar composite.
A first electrode through which sunlight is incident and transmitted;
A second electrode arranged to face the first electrode;
A photoactive layer positioned between the first electrode and the second electrode; And
And an electrolyte filled between the photoactive layer and the second electrode,
Wherein the photoactive layer comprises the zinc oxide nanorod composite according to claim 11 and a photosensitizing dye adsorbed on the surface of the zinc oxide nanorod composite.
19. The method of claim 18,
Wherein the photoactive layer has a thickness of 3 to 10 mu m.
Forming a first electrode by forming a conductive layer including a conductive material on a transparent substrate;
Growing a zinc oxide nanorod on the first electrode using an ultrasonic chemical growth method;
Forming an oxide nanorod layer on the surface of the zinc oxide nanorod using an ultrasonic chemical growth method to form a zinc oxide nanorod composite;
Forming a photoactive layer by adsorbing a photosensitive dye on the zinc oxide nanorod composite; And
Forming a second electrode over the photoactive layer, and injecting an electrolyte
Wherein the dye-sensitized solar cell comprises a dye-sensitized solar cell.

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