KR101191959B1 - Dye sensitized solar cell and method for manufacturing the same - Google Patents

Abstract

Provided are a dye-sensitized solar cell having an improved electrode structure and a method of manufacturing the same. The dye-sensitized solar cell comprises: i) a first electrode structure adapted to transmit light, ii) a second electrode structure facing the first electrode structure, and iii) a photoelectric positioned between the first electrode structure and the second electrode structure. It includes a conversion layer. The photoelectric conversion layer comprises i) a plurality of porous bodies, ii) a dye adsorbed on the surfaces of the plurality of porous bodies, and iii) a plurality of porous bodies and an electrolyte surrounding the dye. The first electrode structure includes i) a substrate and ii) a conductive layer located on the substrate and comprising a plurality of nanowires.

Description

Dye-Sensitized Solar Cell and Manufacturing Method Thereof {DYE SENSITIZED SOLAR CELL AND METHOD FOR MANUFACTURING THE SAME}

The present invention relates to a dye-sensitized solar cell and a method of manufacturing the same. More specifically, the present invention relates to a dye-sensitized solar cell having an improved electrode structure and a method of manufacturing the same.

In a dye-sensitized solar cell, visible light is absorbed by an n-type nanoparticle semiconductor oxide electrode in which dye molecules are chemically adsorbed on a surface thereof to form a pair of dye molecules with electrons and holes. Electrons are injected into the conduction band of the semiconductor oxide. Electrons injected into the semiconductor oxide electrode are transferred to the electrode through the interface between the nanoparticles to generate a current. The holes generated in the dye molecules receive electrons by the redox electrolyte and are reduced again to generate electromotive force from the dye-sensitized solar cell.

The transparent metal electrode included in the dye-sensitized solar cell described above is widely used in electronic devices such as display devices. More specifically, the transparent metal electrode is widely used in electronic components such as an image sensor, a solar cell, a touch screen, an electromagnetic shielding material, and a static electricity suppressing material which simultaneously require light transmission characteristics and conductivity.

Indium tin oxide (ITO) has been mainly used as a material of the transparent metal electrode. ITO has excellent conductivity and transparency. However, ITO has fundamentally good physical properties and shows a great difference from the substrate in the coefficient of thermal expansion. Therefore, the mechanical stability is low when applying ITO to the touch screen, bending or folding the thin film. In addition, in order to manufacture the ITO thin film basically requires a vacuum process, expensive manufacturing cost is consumed. Furthermore, since the manufacturing process of an ITO thin film includes a high temperature process, a plastic substrate is heat-strained and its surface resistance changes. Therefore, carbon nanotubes have been proposed as a material for replacing ITO.

Since carbon nanotubes have high electrical conductivity, mechanical strength, and elasticity, they are highly applicable as a material for transparent electrodes. However, in the case of carbon nanotubes, sheet resistance, which reflects this macroscopically, becomes larger than expected due to contact resistance at the junction. Therefore, the electrical conductivity of the carbon nanotube thin film is lower than that of the ITO thin film. Furthermore, the thin film made of carbon nanotubes made once has low stability and is very difficult to maintain its physical properties for a long time. In addition, due to the strong agglomeration between the carbon nanotubes, even using a specific solvent and dispersant, it is difficult to make a thin film having uniform properties.

The present invention provides a dye-sensitized solar cell including an electrode structure having excellent electrical conductivity and catalytic function. In addition, the present invention provides a method for manufacturing the dye-sensitized solar cell.

Dye-sensitized solar cell according to an embodiment of the present invention, i) a first electrode structure applied to transmit light, ii) a second electrode structure facing the first electrode structure, and iii) the first electrode structure and the first It includes a photoelectric conversion layer located between the two electrode structure. The photoelectric conversion layer comprises i) a plurality of porous bodies, ii) a dye adsorbed on the surfaces of the plurality of porous bodies, and iii) a plurality of porous bodies and an electrolyte surrounding the dye. The first electrode structure includes i) a substrate and ii) a conductive layer located on the substrate and comprising a plurality of nanowires.

The plurality of nanowires may include i) a first nanowire, and ii) a second nanowire crossing each other with the first nanowire to form an overlap with the first nanowire. The height of the overlap may be less than the sum of the diameter of the first nanowire and the diameter of the second nanowire. Nanowires may comprise platinum (Pt). Nanowires include gold (Au), palladium (Pd), iridium (Ir), silver (Ag), rhodium (Rh), ruthenium (Ru), nickel (Ni), stainless steel, aluminum (Al), titanium (Ti) It may further include one or more materials selected from the group consisting of molybdenum (Mo), chromium (Cr), copper (Cu) and tungsten (W).

The opening ratio of the conductive layer may be 20% to 80%. More preferably, the opening ratio of the conductive layer may be 40% to 60%. The plurality of nanowires may include a plurality of nanostructures, and the plurality of nanostructures may include nanocrystals or nanoparticles. The average particle diameter of the plurality of nanostructures may be 5 nm to 50 nm. The substrate may comprise one or more materials selected from the group consisting of glass, quartz, plastic, and light transmissive polymers.

Method for manufacturing a dye-sensitized solar cell according to an embodiment of the present invention, i) providing a mixed solution containing a polymer and a metal precursor, ii) spinning a mixed solution on a substrate to provide a nanofiber thin film iii) heat treating the nanofiber thin film to provide a first electrode structure comprising a conductive layer, iv) providing a second electrode structure facing the first electrode structure, and v) a first electrode structure and a first Providing a photoelectric conversion layer between the two electrode structures.

The method of manufacturing a dye-sensitized solar cell according to an embodiment of the present invention may further include heat pressing the nanofiber thin film after providing the nanofiber thin film. In the step of thermally pressing the nanofiber thin film, the nanofiber thin film may be thermally pressed at a temperature higher than the glass transition temperature of the polymer. In the step of providing a mixed solution, the polymer is polymethyl methacrylate (PMMA), polyvinylpyrrolidone (PVP), polyvinyl acetate (PVAC), polyvinyl alcohol (polyvinyl acohol, PVA) and polystyrene (PS) and one or more materials selected from the group consisting of. In the step of providing a mixed solution, the metal precursor is one or more selected from the group consisting of chloroplatinic acid hexahydrate (H ₂ PtCl ₆ ), silver nitrate (AgNO ₃ ) and chloroauric acid (HAuCl ₄ ). It may include a substance.

In the providing of the first electrode structure, the nanofiber thin film may be heat-treated at a temperature higher than or equal to the reduction temperature of the metal precursor while pressing. The metal precursor is chloroplatinic acid hexahydrate (Chloroplatinic acid hexahydrate (H ₂ PtCl ₆ )), the reduction temperature may be 300 ℃ to 450 ℃. In providing the mixed solution, the mixed solution is one selected from the group consisting of water, ethanol, tetrahydrofuran (THF, Tetrahydrofuran), dimethylformamide (DMF, Dimethylformamide), dimethylacetamide (DMAc, Dimethylacetamide), and toluene It may further comprise the above materials.

It is possible to provide a dye-sensitized solar cell having an excellent photoelectric conversion efficiency while including an electrode structure having both excellent electrical conductivity and a catalyst function. In addition, it is possible to manufacture a dye-sensitized solar cell through a simple process.

1 is a schematic cross-sectional view of a dye-sensitized solar cell according to an embodiment of the present invention.
FIG. 2 is a schematic flowchart illustrating a method of manufacturing the dye-sensitized solar cell of FIG. 1.
3 is a view schematically showing a nanofiber thin film manufacturing apparatus used in the step of providing a nanofiber thin film of FIG.
Figure 4 is a scanning electron micrograph of the nanofiber thin film prepared according to the experimental example of the present invention.
5 is a scanning electron micrograph of a conductive layer prepared by heat-treating the nanofiber thin film of FIG. 4.
6 is a transmission electron micrograph, a diffraction pattern, and an energy dispersive X-ray spectroscopy (EDS) spectrum of the nanowires included in the conductive layer of FIG. 5.
FIG. 7 is a graph of light transmittance according to various electrospinning times of the conductive layer of FIG. 5.
8 is a graph showing light conversion efficiency and basic characteristics of the dye-sensitized solar cell manufactured according to the experimental example of the present invention.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular forms “a,” “an,” and “the” include plural forms as well, unless the phrases clearly indicate the opposite. As used herein, the term "comprising" embodies a particular characteristic, region, integer, step, operation, element, and / or component, and other specific characteristics, region, integer, step, operation, element, component, and / or group. It does not exclude the presence or addition of.

Terms representing relative space, such as "below "," above ", and the like, may be used to more easily describe the relationship to another portion of a portion shown in the figures. These terms are intended to include other meanings or acts of the apparatus in use, as well as intended meanings in the drawings. For example, when inverting a device in the figures, certain parts that are described as being "below" other parts are described as being "above " other parts. Thus, an exemplary term "below" includes both up and down directions. The device can be rotated 90 degrees or rotated at different angles, and the term indicating the relative space is interpreted accordingly. Also, when referring to a portion as being "on top" of another portion, it may be directly on top of another portion or may be accompanied by another portion in between. In contrast, when a part is mentioned as "directly above" another part, no other part is intervened in between.

Unless defined otherwise, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. Commonly used predefined terms are further interpreted as having a meaning consistent with the relevant technical literature and the present disclosure, and are not to be construed as ideal or very formal meanings unless defined otherwise.

The term “nano” described in the specification means nanoscale and may include micro units. In addition, the terms "nanoparticle" or "nanocrystal" described in the specification means nanoscale objects each having a particle form or a crystalline form. The particle form or crystalline form is not limited to a specific shape and may be variously modified.

As used herein, the term "nanofiber" refers to a material in which a mixture of a polymer and a metal precursor is present in a fine fiber form by spinning. In addition, “nanowire”, which is distinguished from “nanofiber”, is used to heat the “nanofiber” to remove most of the polymer from the “nanofiber” and to leave the remaining material in the state of aggregation of metal nanocrystals or nanoparticles. it means.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

1 schematically illustrates a cross-sectional structure of a dye-sensitized solar cell 100 according to an embodiment of the present invention. The enlarged source of FIG. 1 enlarges and shows the internal structure of the conductive layer 101. FIG. The structure of the dye-sensitized solar cell 100 of FIG. 1 is merely for illustrating the present invention, and the present invention is not limited thereto. Therefore, the structure of the dye-sensitized solar cell 100 can be modified in other forms.

As shown in FIG. 1, the dye-sensitized solar cell 100 includes a first electrode structure 10, a photoelectric conversion layer 20, and a second electrode structure 30. In addition, the dye-sensitized solar cell 100 may further include other elements as necessary.

Light is transmitted into the dye-sensitized solar cell 100 through the first electrode structure 10. Therefore, the first electrode structure 10 needs to be made of a light transmitting material. The first electrode structure 10 includes a conductive layer 101 and a front substrate 103. The conductive layer 101 is located under the front substrate 103. The front substrate 103 may be made of glass, quartz, plastic, or a light transmissive polymer. By manufacturing the front substrate 103 using such a material, light may be efficiently incident on the photoelectric conversion layer 20 without being lost.

As shown in the enlarged circle of FIG. 1, the conductive layer 101 includes a plurality of nanowires 1011. The plurality of nanowires 1011 form a network structure. The nanowires 1011 may include a plurality of nanostructures. The plurality of nanostructures comprise nanocrystals or a plurality of nanoparticles. Preferably, the nanocrystals may be single crystals. The average particle diameter of the nanostructures may be 5 nm to 50 nm. The average particle diameter of the plurality of nanostructures may vary depending on the manufacturing process. The nanowires 1011 described above include platinum. Platinum is an electrically conductive material and functions as a catalyst in dye-sensitized solar cells. Therefore, in the dye-sensitized solar cell, instead of separately forming the electrode layer and the catalyst layer, the conductive layer 101 may be formed at the same time. More specifically, the dye-sensitized solar cell 100 must coat a platinum thin film on a transparent electrode made of indium tin oxide (ITO) in order to activate the electron transfer reaction of the electrolyte at the electrode. However, since the conductive layer 101 can perform the above two functions at the same time, the process can be simplified and the cost can be effectively reduced.

On the other hand, the nanowire 1011 is gold (Au), palladium (Pd), iridium (Ir), silver (Ag), rhodium (Rh), ruthenium (Ru), nickel (Ni), stainless steel, aluminum (Al) , Titanium (Ti), molybdenum (Mo), chromium (Cr), copper (Cu), or tungsten (W). Such materials may be used to greatly improve the electrical conductivity of the conductive layer 101.

The aperture ratio of the conductive layer 101 may be 20% to 80%. More preferably, the opening ratio of the conductive layer 101 may be 40% to 60%. That is, as shown in the enlarged circle of FIG. 1, since light is transmitted through the space between the nanowires 1011, the conductive layer 101 has a constant aperture ratio. When the opening ratio of the conductive layer 20 is too low, light does not penetrate the conductive layer 101 well, so that the photoelectric conversion efficiency of the dye-sensitized solar cell 100 is lowered. In addition, when the opening ratio of the conductive layer 20 is too high, since the number of nanowires 1011 is too small, the electrical conductivity of the conductive layer 101 may decrease. Therefore, the opening ratio of the conductive layer 101 is maintained in the above-described range.

Meanwhile, as shown in the enlarged circle of FIG. 1, the nanowires 1011 include a first nanowire 1011a and a second nanowire 1011b. The second nanowire 1011b crosses the first nanowire 1011a to form an overlapping portion 1013 with the first nanowire 1011a. In the overlapping portion 1013, the second nanowires 1011b are positioned on the first nanowires 1011a and pressed by the first nanowires 1011a to form a somewhat crushed diameter. This is because the conductive layer 101 can be thermally pressurized when the conductive layer 101 is manufactured in order to improve the electrical conductivity of the conductive layer 101. In this case, the nanofibers intersecting with each other (shown in FIG. 4) are pressed together and then present in the form shown in FIG. 1 through a heat treatment step in a subsequent step. Since the first nanowires 1011a and the second nanowires 1011b overlap each other and are attached to each other by thermal pressure, the nanowires 1011 are interconnected to greatly increase the electrical conductivity of the conductive layer 101. Can be improved.

Therefore, as shown in the enlarged circle of FIG. 1, since the second nanowire 1011b is formed by being pressed on the first nanowire 1011a in the overlapping portion 1013, the height of the overlapping portion 1013 is the first nanowire ( Less than the sum of the diameter of 1011a) and the diameter of the second nanowire 1011b. As a result, since the contact area between the nanowires 1011 is increased, the electrical conductivity of the conductive layer 101 can be improved as a whole.

As shown in FIG. 1, the photoelectric conversion layer 20 includes a plurality of porous bodies 201, a dye 203, and an electrolyte 205. In addition, the photoelectric conversion layer 20 may further include other materials. The dye 203 is adsorbed on the surface of the plurality of porous bodies 201. The electrolyte surrounds the plurality of porous bodies 201 and the dye. The photons passing through the first electrode structure 10 are absorbed by the dye 203, the dye 203 is excited to generate electrons, and the electrons pass through the plurality of porous bodies 201 and the electrolyte 205. It is supplied to the outside through the electrode structure 10 and the second electrode structure 30 to generate an electromotive force. Since the structure of the photoelectric conversion layer 20 can be easily understood by those skilled in the art, detailed description thereof will be omitted.

Meanwhile, as shown in FIG. 1, the second electrode structure 30 includes an electrode layer 301 and a back substrate 303. The electrode layer 301 is positioned on the rear substrate 303 and transfers electrons generated in the photoelectric conversion layer 20 to the outside. Since the second electrode structure 30 does not directly contact the sun, an opaque metal having high reflectance may be used as the material of the electrode layer 301. Hereinafter, a method of manufacturing the dye-sensitized solar cell 100 of FIG. 1 will be described in detail with reference to FIG. 2.

FIG. 2 schematically shows a flowchart of a manufacturing method of the dye-sensitized solar cell 100 of FIG. 1. The manufacturing method of the dye-sensitized solar cell 100 of FIG. 2 is merely for illustrating the present invention, and the present invention is not limited thereto. Therefore, the manufacturing method of the dye-sensitized solar cell 100 can be modified differently.

As shown in Figure 2, the method for manufacturing a dye-sensitized solar cell 100, i) providing a mixed solution containing a polymer and a metal precursor (S10), ii) spinning the mixed solution on a substrate nano Providing a fiber thin film (S20), iii) heat pressing the nanofiber thin film (S30), iv) heat treating the nanofiber thin film to provide an electrode structure including a conductive layer (S40), v) electrode Providing another electrode structure facing the structure (S50), and vi) providing a photoelectric conversion layer between the electrode structures (S60). In addition, the method of manufacturing the dye-sensitized solar cell 100 may further include other steps. In addition, the step (S30) of thermally pressing the nanofiber thin film described above may be omitted, and the order of each step (S40) to step (S60) may be changed.

First, in step S10 to provide a mixed solution containing a polymer and a metal precursor. Here, the polymer may be polymethyl methacrylate (PMMA), polyvinylpyrrolidone (PVP), polyvinyl acetate (PVAC), polyvinyl alcohol (polyvinyl acohol, PVA) or polystyrene ( polystyrene, PS) and the like can be used. In addition, chloroplatinic acid hexahydrate (H ₂ PtCl ₆ ), silver nitrate (AgNO ₃ ) or chloroauric acid (HAuCl ₄ ) may be used as the metal precursor. The mixed solution may include water, ethanol, tetrahydrofuran (THF, Tetrahydrofuran), dimethylformamide (DMF, Dimethylformamide), dimethylacetamide (DMAc, Dimethylacetamide) or toluene. Here, water, ethanol and dimethylformamide are polar solvents. For example, a mixed solution can be prepared by dissolving polyvinylpyrrolidone and chloroplatinic acid hexahydrate in a solvent in which water, ethanol and dimethylformamide are respectively mixed in a predetermined ratio. In this case, a viscous polymer mixed solution in which metal precursors are mixed is prepared.

Next, in step S20 to provide a nanofiber thin film by spinning a mixed solution on the substrate. Here, the mixed solution can be spun using methods such as electro-spinning, melt-blown, flash spinning, or electrostatic melt-blown. have. The nanofiber thin film is manufactured in the form of a thin film in which a plurality of nanofibers are entangled into a network.

Figure 3 schematically shows a nanofiber thin film manufacturing apparatus used in the step (S20) to provide a nanofiber thin film of FIG. That is, FIG. 3 schematically shows an apparatus for forming a nanofiber thin film by spinning in step S20 of FIG. 2. The manufacturing process of the nanofiber thin film of FIG. 3 is merely for illustrating the present invention, and the present invention is not limited thereto. Therefore, the manufacturing process of the nanofiber thin film can be modified differently.

As shown in FIG. 3, an electrospinning apparatus 200 is provided to form a nanofiber thin film. The electrospinning apparatus 200 includes a syringe pump 40, a conduit 45, a injection tip 50, a metal plate 60, and a power source 70. In addition, the electrospinning apparatus 200 may further include other components as necessary. For example, the electrospinning apparatus 200 may further include an automatic device (not shown) for performing a plane periodic movement of the metal plate 40 at a constant speed. Through this, it is possible to manufacture a uniformly formed nanofiber thin film.

As shown in FIG. 3, the syringe pump 40 injects the mixed solution provided in step S10 of FIG. 2 at a constant rate. Since the conduit 45 is connected to the syringe pump 40, the conduit 45 transfers the mixed solution discharged from the syringe pump 40. The injection tip 50 is connected to the end of the conduit 45. Here, the injection tip 50 also includes a conducting wire located below it. The power source is electrically connected to the scan tip 50 and the metal plate 60 to apply a high voltage. The metal plate 40 is grounded at the bottom. As the high voltage is applied, the mixed solution is dispersed and attached to the metal plate 40 in the form of a nanofiber thin film. Since the electrospinning process can be easily understood by those skilled in the art, detailed descriptions of the remaining parts will be omitted.

When using metal nanoparticles synthesized in the form of wires, agglomeration between particles is severe due to strong van der Waals forces. Therefore, the process of thinning by redispersing it is difficult as a process using carbon nanotubes, in which a large amount of raw material is lost or conductivity and light transmittance are reduced. The electrospinning method can easily solve these problems. In other words, it is possible to economically process through the electrospinning method, it is possible to produce a thin film made of nanofibers of a uniform type that is not agglomerated. As a result, the electrode structure manufactured by the electrospinning method can be economically mass produced while maintaining high light transmittance and conductivity.

When the process returns to step S30 of FIG. 2, the nanofiber thin film is thermally pressed in step S30. In this case, the nanofiber thin film is heat-treated at a temperature higher than the reduction temperature of the metal precursor while pressing the nanofiber thin film. As a result, the nanofibers included in the nanofiber thin film are well adhered to improve their electrical conductivity.

In step (S30) it is possible to reduce the metal from the metal precursor by thermally pressing the nanofiber thin film at a temperature above the reduction temperature of the metal precursor. Therefore, a conductive layer made of metal can be formed. For example, when the metal precursor is chloroplatinic acid hexahydrate, the reduction temperature of the metal precursor may be 300 ° C to 450 ° C. If the reduction temperature of chloroplatinic acid hexahydrate is too low, platinum is not reduced well from chloroplatinic acid hexahydrate. In addition, when the reduction temperature of chloroplatinic acid hexahydrate is too high, platinum reduced from chloroplatinic acid hexahydrate may be oxidized. Therefore, the reduction temperature of the metal precursor is adjusted to the above range. When the nanofiber thin film is thermally pressurized, the nanofiber thin film is thermally pressed at a temperature above the glass transition temperature of the polymer. As a result, the polymer may be removed from the nanofiber thin film while the polymer is backed off.

Next, in step S40, the nanofiber thin film is heat-treated to provide an electrode structure including a conductive layer. That is, since the polymer is removed by volatile oxidation from the nanofiber thin film by heat treatment, an electrode structure including a porous conductive layer having a network structure in which only the reduced metal nanowires remain is manufactured.

The electrode structure manufactured through the above-described process has a level of electrical conductivity and light transmittance that can replace the conventional ITO electrode. The electrode structure may be economically process designed with a large area. In addition, when manufacturing an electrode structure including a metal nanowire network through the above-described process, it is possible to manufacture an electrode structure having the same transparency and the electrical conductivity of the ITO thin film level. For example, an electrode structure manufactured using nanowires made of silver (Ag) may have a transparency of 80% or more and a low sheet resistance close to 10 Ω / sq. This transparency and sheet resistance are very close to the performance of the conventional indium tin oxide transparent conductive film.

On the other hand, nano-lattice transparent conductive films made of gold, silver, and copper using lithography have similar transparency and sheet resistance properties, but they are economically difficult and expensive due to the use of expensive lithography.

Next, in step S50, another electrode structure facing the aforementioned electrode structure is provided. Another electrode structure may be made of a material having a high reflectance in order to reduce light loss because it does not need to be incident to sunlight. In addition, the same electrode structure as the electrode structure mentioned above can also be used as it is.

Finally, in step S60, a dye-sensitized solar cell may be manufactured by providing a photoelectric conversion layer and bonding between the electrode structures. The combined manufacturing process of the dye-sensitized solar cell in step S60 can be easily understood by those skilled in the art, and thus detailed description thereof will be omitted. Through the above-described process it can be produced a dye-sensitized solar cell excellent in electrical conductivity and light transmittance.

Hereinafter, the present invention will be described in more detail with reference to experimental examples. These experimental examples are only for illustrating the present invention and the present invention is not limited thereto.

Nano thin film manufacturing experiment

Polyvinylpyrrolidone (PVP, Polyvinylpyrrolidone) and chloroplatinic acid hexahydrate (H ₂ PtCl ₆ ) in a solvent mixed with water, ethanol and dimethylformamide (DMF) in a ratio of 1: 1: 2, respectively Were dissolved at concentrations of 0.1 g / mL and 0.25 g / mL, respectively, to prepare a mixed solution including a polymer and a metal precursor. Next, the mixed solution was placed in a syringe pump and electrospun onto a transparent glass substrate positioned on a lower grounded metal plate to form a nanofiber thin film on the transparent glass substrate. In this case, the distance between the scanning tip and the substrate was about 7 cm. In addition, the applied high voltage was 1 kV / cm, the solution injection speed was about 0.7 μL / min. The electrospinning time was adjusted differently to control the thickness (density) of the nanofibers.

Nano thin film manufacturing experiment results

Under the above experimental conditions, polyvinylpyrrolidone (PVP) nanofibers including platinum precursors were stably electrospun. The spun nanofibers were applied in a uniform thin film form on the substrate.

Figure 4 shows a scanning electron micrograph of the nanofiber thin film prepared according to the experimental example of the present invention described above.

As shown in FIG. 4, it was found that the nanofiber thin film was formed. The nanofiber thin film had a uniform network structure, and its thickness was about 300 nm to 800 nm.

Conductive layer  Manufacturing experiment

The conductive layer was prepared by reducing the metal precursor while oxidizing and removing the polymer by heat-treating the nanofiber thin film. The substrate with the nanofiber thin film formed in the heating furnace was heat-treated at 300 ° C. for 2 hours, and subsequently heat-treated at 450 ° C. for 2 hours.

Conductive layer  Manufacturing experiment result

5 is a scanning electron micrograph of a conductive layer prepared by heat-treating the nanofiber thin film of FIG. 4 through the above-described process.

As shown in FIG. 5, a conductive layer of a platinum nanowire network structure having a certain transparency was generated through a heat treatment process. That is, it was confirmed that the platinum nanowires remaining after the polymer was removed did not form a uniform network structure. The diameter of the platinum nanowires was about 40 nm to 70 nm, which was reduced to about 10% of the diameter of the polymer nanofibers before heat treatment.

FIG. 6 is a diagram illustrating a transmission electron micrograph, a diffraction pattern, and an EDS spectrum of a nanowire included in the conductive layer of FIG. 5.

As shown in FIG. 6, the platinum nanowires consisted of pure platinum crystals. Platinum nanowires consisted of a combination of platinum crystals of several nanometers in size. On the other hand, as shown in the diffraction pattern of Figure 6, it can be seen that the crystals are pure platinum single crystals.

The lower EDS spectrum of FIG. 6 shows peaks corresponding to carbon, copper and platinum, respectively. The peaks corresponding to carbon and copper in FIG. 6 are due to a substrate grid used for transmission electron microscopy. Therefore, the platinum peak shows that the chemical composition of the nanowire is pure platinum single crystal.

Conductive layer Light transmittance  And conductivity measurement experiments

The light transmittance of the conductive layer was measured. In order to measure the light transmittance, UV-visible-IR transmittance spectroscopy was used.

Conductive layer Light transmittance  And conductivity measurement results

7 is a graph illustrating light transmittance according to various electrospinning times of the conductive layer of FIG. 5.

In FIG. 7, light transmittances of metal nanowire specimens having different densities according to emission times were measured in the wavelength range of 300 nm to 800 nm. In FIG. 7, the sheet resistance of the same specimens was measured using four probes, compared with the transparency of each specimen in the light transmittance 550 nm wavelength band. The measured sheet resistance was about 100 Ω / sq when the transparency was 80% and about 40 Ω / sq when the transparency was 68%. This low sheet resistance has shown that platinum nanowire networks can be effectively used in a variety of devices as transparent conductive films. Oxides or impurities did not degrade the electrical conductivity of the platinum nanowire network.

Dye-Sensitized Solar Cell Manufacturing Experiment

The dye-sensitized solar cell was manufactured using the conductive layer manufactured by the above-mentioned method. That is, the transparent electrode made of FTO (florinated tin oxide) used in the conventional dye-sensitized solar cell was replaced with a conductive layer prepared according to the above experimental example. Since the conductive layer having the platinum nanowire network structure also functions as a catalyst, there was no need to use a catalyst separately in the dye-sensitized solar cell. Since the method of manufacturing the remaining dye-sensitized solar cell can be easily understood by those skilled in the art, detailed description thereof will be omitted. Meanwhile, in the conventional process, the process of obtaining the reduced platinum thin film by coating the platinum precursor solution on the FTO counter electrode and then performing heat treatment could be omitted during the manufacture of the dye-sensitized solar cell.

Dye-Sensitized Solar Cell Manufacturing Experiment Results

8 is a graph showing light conversion efficiency and basic characteristics of the dye-sensitized solar cell manufactured according to the experimental example of the present invention.

As shown in FIG. 8, the sheet resistance of the transparent electrode of the platinum nanowire network used in the dye-sensitized solar cell was about 70 Ω / sq. This was smaller than the sheet resistance of the conventional FTO having a sheet resistance of about 10? / Sq. On the other hand, the photoelectric conversion efficiency of the transparent electrode according to the experimental example of the present invention is 6.0%, while the photoelectric conversion efficiency of the conventional FTO counter electrode is 7.2%, showing about 80% or more performance compared to the conventional FTO counter electrode It became. Therefore, it was confirmed that the conductive layer of the platinum nanowire network structure prepared according to the experimental example of the present invention can exhibit sufficient performance as a catalyst electrode. When using the electrode having a sheet resistance of 40Ω / sq or less by controlling the thickness and density of the nanowire, it is expected to exhibit the same photoelectric conversion efficiency as the dye-sensitized solar cell using a conventional FTO.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it is within the scope of the present invention.

10, 30. Electrode structure 100. Dye-sensitized solar cell
101. Conductive layers 103, 303. Substrate
1011a, 1011b, 1011. Nanowire 1013. Overlap
20. Photoelectric conversion layer 200. Electrospinning apparatus
201.Porous Body 203.Dyestuffs
205. Electrolyte 301. Electrode layer
40. Syringe pumps 45. Conduits
50. Tip 60. Metal plate
70. Power

Claims (17)

A first electrode structure adapted to transmit light,
A second electrode structure facing the first electrode structure, and
A photoelectric conversion layer disposed between the first electrode structure and the second electrode structure
Including,
The photoelectric conversion layer,
Multiple porous bodies,
A dye adsorbed on the surface of the plurality of porous bodies, and
An electrolyte surrounding the plurality of porous bodies and the dye
/ RTI >
The first electrode structure,
Substrate, and
A conductive layer disposed on the substrate and including a plurality of nanowires including platinum that activates an electron transfer reaction of the electrolyte and is in contact with the photoelectric conversion layer;
Including,
The plurality of nanowires,
A first nanowire, and
A second nanowire intersecting with the first nanowire to form an overlap with the first nanowire;
Including,
The height of the overlap portion is a dye-sensitized solar cell smaller than the sum of the diameter of the first nanowire and the diameter of the second nanowire. delete delete The method of claim 1,
The plurality of nanowires include gold (Au), palladium (Pd), iridium (Ir), silver (Ag), rhodium (Rh), ruthenium (Ru), nickel (Ni), stainless steel, aluminum (Al), titanium Dye-sensitized solar cell further comprises one or more materials selected from the group consisting of (Ti), molybdenum (Mo), chromium (Cr), copper (Cu) and tungsten (W). The method of claim 1,
The aperture ratio of the conductive layer is 20% to 80% dye-sensitized solar cell. The method of claim 5,
The aperture ratio of the conductive layer is 40% to 60% dye-sensitized solar cell. The method of claim 1,
The plurality of nanowires include a plurality of nanostructures, the plurality of nanostructures comprises nanocrystals or nanoparticles. The method of claim 7, wherein
An average particle diameter of the plurality of nanostructures is 5nm to 50nm dye-sensitized solar cell. The method of claim 1,
The substrate is a dye-sensitized solar cell comprising at least one material selected from the group consisting of glass, quartz, plastic and light transmissive polymer. Providing a mixed solution comprising a polymer and a metal precursor,
Spinning the mixed solution on a substrate to provide a nanofiber thin film,
Thermally pressing the nanofiber thin film,
Heat treating the nanofiber thin film to provide a first electrode structure including a conductive layer,
Providing a second electrode structure facing the first electrode structure, and
Providing a photoelectric conversion layer between the first electrode structure and the second electrode structure
Including,
In the providing of the photoelectric conversion layer, the photoelectric conversion layer includes an electrolyte, the photoelectric conversion layer and the conductive layer are in contact with each other, the conductive layer comprises a plurality of nanowires, the plurality of nanowires Method of manufacturing a dye-sensitized solar cell comprising platinum to activate the electron transfer reaction of the electrolyte. delete The method of claim 10,
In the step of thermally pressing the nanofiber thin film,
The method of manufacturing a dye-sensitized solar cell for thermally pressing the nanofiber thin film at a temperature higher than the glass transition temperature of the polymer. The method of claim 10,
In the step of providing the mixed solution,
The polymer is polymethyl methacrylate (PMMA), polyvinylpyrrolidone (PVP), polyvinyl acetate (PVAC), polyvinyl alcohol (polyvinyl acohol, PVA) and polystyrene (polystyrene, PS) method for producing a dye-sensitized solar cell comprising at least one material selected from the group consisting of. The method of claim 10,
In the step of providing the mixed solution,
The metal precursor is a dye-sensitized type including one or more substances selected from the group consisting of chloroplatinic acid hexahydrate (H ₂ PtCl ₆ ), silver nitrate (AgNO ₃ ) and chloroauric acid (HAuCl ₄ ). Manufacturing method of solar cell. The method of claim 10,
In the step of providing the first electrode structure,
A method of manufacturing a dye-sensitized solar cell, wherein the nanofiber thin film is heat-treated at a temperature equal to or lower than a reduction temperature of the metal precursor. 16. The method of claim 15,
The metal precursor is chloroplatinic acid hexahydrate (Chloroplatinic acid hexahydrate (H ₂ PtCl ₆ )), the reduction temperature is 300 ℃ to 450 ℃ manufacturing method of a dye-sensitized solar cell. The method of claim 10,
In the step of providing the mixed solution,
The mixed solution is a dye further comprising at least one substance selected from the group consisting of water, ethanol, tetrahydrofuran (THF, Tetrahydrofuran), dimethylformamide (DMF, Dimethylformamide), dimethylacetamide (DMAc, Dimethylacetamide), and toluene Method of manufacturing a sensitive solar cell.

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