KR102388771B1 - Transparent electrode for photovoltaic textiles, manufacturing method thereof and photovoltaic textiles comprising the transparent electrode - Google Patents

Abstract

The present invention relates to a transparent electrode for a solar cell fiber, a method for manufacturing the same, and a solar cell fiber including the transparent electrode, and more particularly, to a solar cell fiber by bonding a conductive polymer on a polyvinylidene chloride-based polymer nanofiber web. By manufacturing a transparent electrode for use, light transmittance and electrical conductivity can be significantly improved, and compared to the existing glass-based transparent electrode, it is light in weight, small in volume, and has excellent flexibility and durability.

Description

Transparent electrode for solar cell fiber, manufacturing method thereof, and solar cell fiber including the transparent electrode

The present invention relates to a transparent electrode for a solar cell fiber excellent in light transmittance and electrical conductivity, a manufacturing method thereof, and a solar cell fiber comprising the transparent electrode.

With the development of IoTs (Internet of Things) technology following the 4th industrial revolution, a hyper-connected society has arrived in which all things are connected through a single network. Due to this, in the near future, functions performed by smartphones will be operated in the form of clothing. Smart Clothing refers to clothing that combines ICT (Information & Communication Technology) and textile technology, and is composed of input, processing, output, and power technology. Currently, the power supply of smart clothing is applied by using a snap-button to connect to a lithium battery or the like. Therefore, it has many problems, such as a limitation in that it is heavy and bulky, a short battery life, safety, and environmental pollution.

In order to solve this problem, it is necessary to develop a textile-based power supply device. Energy is an essential element in power technology, and in particular, the importance of power supply and storage management for smart clothing operation in a wireless environment is increasing. Solar energy is a clean energy and has the advantages of high efficiency, permanent energy supply, and the ability to be converted into electric energy without any restrictions on location. A solar cell is a battery that converts solar energy into electrical energy, and as long as there is a light source, it can be used indoors and outdoors, so it is suitable as a power supply device for smart clothing. However, currently commercialized solar cells use a hard glass substrate, so flexibility and portability are not good, and their application to clothing is limited due to low durability against bending.

Photovoltaic Textiles are clothing materials such as fibers, threads, and fabrics that can convert light energy into electrical energy. Currently, solar cell fibers are mainly produced as organic-based dye-sensitized and organic thin-film solar cells. Dye-sensitized solar cells use the principle of photosynthesis of plants and use vegetable dyes, and organic thin-film solar cells mainly use P3HT:PCBM polymer composite. While they have the advantages of light weight, portability, and simple process, they have the disadvantage of low energy conversion efficiency. In addition, the solar cell combining this with the fiber form is still in the early stages of development, and the advantages of lightness, portability, and simple process of the existing solar cell are maintained, and the energy conversion efficiency and flexibility of the solar cell fiber are improved continuously. this is being requested

On the other hand, in optics, transparency is a characteristic in which light passes through a material without being scattered. Glass, the most representative of transparent materials, is an amorphous material itself, and thus has transparency because the distance between its molecules is long. Transparent electrodes (Transparent Conducting Electrodes, TCEs) are electrodes having high light transmittance in a visible light region and electrical conductivity at the same time. Depending on the sheet resistance of the transparent electrode, it can be applied to various industries such as touch screen panels, displays, and solar cell textiles, and thus the demand for transparent electrodes is gradually increasing.

Currently, the most widely used transparent electrode material is ITO (Indium Tin Oxide). ITO shows a sheet resistance of 10 Ω/sq or less and a light transmittance of 90% in the visible region, making it a suitable transparent electrode material for solar cells. However, as the demand increases, concerns about the depletion of indium, a rare metal, and a continuous price increase are caused. In addition, the glass-based ITO transparent electrode has limitations in that it has very weak mechanical strength and no flexibility.

Accordingly, metals, carbon allotropes, etc. have been proposed as materials to replace the ITO transparent electrode. Among various conductive materials, silver nanowires (AgNWs), a metal, have a disadvantage in that the light transmittance decreases as the density increases, carbon nanotubes (CNTs) are difficult to disperse for a solution process, and graphene is difficult to form with a uniform thickness. There is a limitation in that the process for In addition, when the transparent electrode material is glass, transparency is excellent, but flexibility is not good.

Korean Patent Registration No. 10-1706125

In order to solve the above problems, an object of the present invention is to provide a transparent electrode for solar cell fibers with significantly improved light transmittance and electrical conductivity.

Another object of the present invention is to provide a solar cell fiber including the transparent electrode.

Another object of the present invention is to provide a product including the solar cell fiber.

Another object of the present invention is to provide a method for manufacturing a transparent electrode for a solar cell fiber.

The present invention is a polyvinylidene fluoride-based polymer nanofiber web; and a conductive polymer bonded to the surface of the polyvinylidene fluoride-based polymer nanofiber web and the fiber surface inside the web; as a transparent electrode for solar cell fibers, the transparent electrode is FT-IR analysis result ① 872 to 874 cm ^-1 , ② 1179 to 1181 cm ^-1 , and ③ 1291 to 1293 cm ^-1 The first α-form crystal peak, the second α-form crystal peak, and the β-form crystal peak are respectively shown in the wavelength range, and the (first The absorption intensity ratio of α-form crystal peak)/(second α-form crystal peak) is 0.9 to 1.2, and the absorption intensity ratio of (second α-form crystal peak)/(β-form crystal peak) is 1.4 to 1.8, The (β-form crystal peak)/(first α-form crystal peak) absorption intensity ratio is 0.5 to 0.7 to provide a transparent electrode for solar cell fibers.

In addition, the present invention provides a solar cell fiber including the transparent electrode.

The present invention also provides a product including the solar cell fiber.

In addition, the present invention includes the steps of preparing a mixed solution by mixing an aqueous dispersion of a conductive polymer and an organic solvent; coating the mixed solution on the polyvinylidene fluoride-based polymer nanofiber web; and manufacturing a transparent electrode by drying the matrix polymer nanofiber web coated with the mixed solution;

The transparent electrode for solar cell fibers according to the present invention can significantly improve light transmittance and electrical conductivity by bonding a conductive polymer on a polyvinylidene chloride-based polymer nanofiber web.

In addition, the transparent electrode for solar cell fiber according to the present invention has advantages in that it is light in weight and small in volume, and has excellent flexibility and durability compared to the conventional glass-based transparent electrode.

The effects of the present invention are not limited to the above-mentioned effects. It should be understood that the effects of the present invention include all effects that can be inferred from the following description.

1 is a diagram schematically showing a method for preparing a PEDOT:PSS/DMSO mixed solution.
2 shows PEDOT:PSS mixed in 9 volume ratios (10:0, 9:1, 8:2, 7:3, 6:4, 5:5, 4:6, 3:7, 2:8) A method for preparing a transparent electrode sample using a /DMSO mixed solution is schematically shown.
3 is a view schematically showing a method of manufacturing a photovoltaic fiber.
4 shows the measurement results of sheet resistance according to the volume ratio of the PEDOT:PSS/DMSO mixed solution for the transparent electrodes (P10D0, P9D1, P8D2, P7D3, P6D4, P5D5, P4D6, P3D7, P2D8) prepared in Example 1 of the present invention; This is the graph shown.
5 is an untreated PVDF nanofiber web sample and a transparent electrode (P10D0, P9D1, P8D2, P7D3, P6D4, P5D5, P4D6, P3D7, P2D8) prepared in Example 1 of the present invention PEDOT: PSS / DMSO mixed solution It is a graph showing the measurement result of the light transmittance spectrum according to the volume ratio.
6 is an FE-SEM image of an untreated PVDF nanofiber web.
7 is a PVDF nanofiber web according to the volume ratio of PEDOT: PSS/DMSO mixed solution for the transparent electrodes (P10D0, P9D1, P8D2, P7D3, P6D4, P5D5, P4D6, P3D7, P2D8) prepared in Example 1 of the present invention; FE-SEM image of the surface microstructure of
8 is a graph showing the measurement of the thickness of the untreated PVDF nanofiber web sample and the P10D0 sample, P9D1 sample, P2D8 sample, and P3D7 sample of Example 1 of the present invention.
9 is an untreated PVDF nanofiber web sample, a P10D0 sample treated with only PEDOT:PSS of Example 1 of the present invention, a P9D1 sample having the best electrical conductivity, a P2D8 sample having the lowest electrical conductivity, and the best performance as a transparent electrode It is an AFM image of the surface particle shape and surface roughness of the P3D7 sample having the index.
10 shows the results of FT-IR analysis of the untreated PVDF nanofiber web.
11 shows the results of FT-IR analysis of PEDOT:PSS aqueous dispersion.
12 shows the chemical composition of each sample according to the volume ratio of the PEDOT:PSS/DMSO mixed solution for the transparent electrodes (P10D0, P9D1, P8D2, P7D3, P6D4, P5D5, P4D6, P3D7, P2D8) prepared in Example 1 of the present invention; It is the result of FT-IR analysis showing the structural change.
13 shows the average of each sample according to the volume ratio of PEDOT:PSS/DMSO mixed solution for the transparent electrodes (P10D0, P9D1, P8D2, P7D3, P6D4, P5D5, P4D6, P3D7, P2D8) prepared in Example 1 of the present invention; The result of calculating the figure of merit (φ _TC ) using the sheet resistance value (R _sh ) and the average light transmittance (T _av ) is shown.
14 is a result of measuring the current-voltage characteristics of the conventional FTO transparent electrode-based dye-sensitized solar cell and the solar cell fiber using the transparent electrode (P3D7) prepared in Example 1 of the present invention.

Hereinafter, the present invention will be described in more detail by way of one embodiment.

In the present invention, nanofiber means a fiber having an average fiber diameter of 1,000 nm or less.

The present invention relates to a transparent electrode for a solar cell fiber, a manufacturing method thereof, and a solar cell fiber including the transparent electrode.

Specifically, the present invention is a polyvinylidene fluoride-based polymer nanofiber web; and a conductive polymer bonded to the surface of the polyvinylidene fluoride-based polymer nanofiber web and the fiber surface inside the web; as a transparent electrode for solar cell fibers, the transparent electrode is FT-IR analysis result ① 872 to 874 cm ^-1 , ② 1179 to 1181 cm ^-1 , and ③ 1291 to 1293 cm ^-1 The first α-form crystal peak, the second α-form crystal peak, and the β-form crystal peak are respectively shown in the wavelength range, and the (first The absorption intensity ratio of α-form crystal peak)/(second α-form crystal peak) is 0.9 to 1.2, and the absorption intensity ratio of (second α-form crystal peak)/(β-form crystal peak) is 1.4 to 1.8, The (β-form crystal peak)/(first α-form crystal peak) absorption intensity ratio is 0.5 to 0.7 to provide a transparent electrode for solar cell fibers.

The polyvinylidene fluoride-based polymer nanofiber web is a nonwoven, nanofiber aggregate of nanometer diameter fibers in which nanofibers are randomly integrated while forming numerous small pores like a three-dimensional network. The polyvinylidene fluoride-based polymer nanofiber web has a large surface area compared to its volume and has excellent properties such as ultra-thin film, ultra-light weight, and flexibility, so that it can be applied as a transparent electrode requiring both electrical conductivity and transparency. Preferably, the polyvinylidene fluoride-based polymer nanofiber web may have an average fiber diameter of 100 to 800 nm, and a cotton weight of 1 to 30 g/m ² . More preferably, the average fiber diameter is 200 to 500 nm, and the cotton weight may be 3 to 5 g/m ² . At this time, if any one of the average fiber diameter and the cotton weight range is not satisfied, the specific surface area and flexibility may be reduced or the transparency may be poor.

The polyvinylidene fluoride-based polymer may be a homopolymer or copolymer polyvinylidene fluoride-based polymer. Specifically, the polyvinylidene fluoride-based polymer is polyvinylidene fluoride (poly(vinylidene fluoride)), poly(vinylidene fluoride-co-hexafluoropropylene) (poly(vinylidene fluoride-co-hexafluoropropylene)), Poly(vinylidene fluoride-co-tetrafluoroethylene) and poly(vinylidenefluoride-co-trifluoroethylene) (poly(vinylidenefluoride-co-trifluoroethylene)) It may be at least one selected from the group consisting of, preferably polyvinylidene fluoride (PVdF).

In particular, the polyvinylidene fluoride (PVdF) polymer has a repeating unit of (CH ₂ -CF ₂ ) _n compared to matrix polymers of conventional transparent electrodes, and has a crystal area and an amorphous area. It is a mixed semi-crystalline polymer. The polyvinylidene fluoride has excellent chemical resistance, heat resistance, and light resistance characteristics due to its high chemical and structural fluorine content, symmetric structure of fluorine atoms and strong CF bond, and has advantages such as durability, weather resistance, moisture resistance, and flexibility. Have.

However, since conventional polyvinylidene fluoride appears opaque due to the occurrence of diffuse reflection at the boundary between the crystalline region and the amorphous region, in the present invention, the polyvinylidene fluoride is mixed with a specific solvent to have transparency. . Preferably, the polyvinylidene fluoride is mixed with a DMSO solvent to be described later to twist the structure of the C-F dipole, thereby converting the α-form crystal and the β-form crystal to control crystallinity. The polyvinylidene fluoride whose crystallinity is controlled can be changed to be transparent by reducing diffuse reflection. Accordingly, the polyvinylidene fluoride-based nanofiber web having the advantages of excellent light resistance, flexibility and transparency has advantages applicable to transparent electrodes for solar cell fibers.

The conductive polymer not only has high light transmittance, electrical conductivity, and flexibility, but also has the advantage of being applicable to a solution process. Specific examples of the conductive polymer include polythiophene, polyaniline, PANI, polypyrrole, PPy, polyacetylene, polydiacetylene, and polythiophenevinylene. )), polyfluorene, and poly(3,4-ethylenedioxythiophene) (PEDOT): may be at least one selected from the group consisting of polystyrene sulfonate (PSS). Preferably, the conductive polymer may be PEDOT or PEDOT:PSS, and most preferably PEDOT:PSS.

The poly(3,4-ethylenedioxythiophene) (PEDOT) is a polymer obtained by polymerizing EDOT monomer as a conductive polymer. The PEDOT has high electrical conductivity, excellent stability and flexibility, and is applicable to various fields due to the possibility of a solution process. The conductive polymer, PEDOT, has inherently hydrophobic properties, so a first doping process is required to make it a solution. It can be synthesized as PEDOT:PSS (Poly(3,4-ethylenedioxythiophene):Poly(Styrenesulfonate)) using PSS (Poly(Styrenesulfonate)) having hydrophilic properties as a primary dopant. At this time, in order to completely disperse the PEDOT in water, it is common to mix and synthesize PEDOT and PSS in a weight ratio of 1:2.5 to 1:20. In this case, the PSS that does not bind to the PEDOT forms hydrogen bonds, and the PEDOT:PSS shows a unique core-shell structure. In the core, mainly PEDOT particles are combined with PSS to form a PEDOT-rich core, and in the shell, PSS particles are randomly combined. Bonding in this structure affects the electrical conductivity of PEDOT:PSS. The electrical properties of PEDOT:PSS are generated as free charges move through the thiophene ring in PEDOT. However, the hydrophilic PSS polymer has insulating properties and, structurally, the PEDOT-rich core is surrounded by the PSS shell, which prevents the flow of electrons. Accordingly, pure PEDOT:PSS exhibits very low electrical properties.

In order to solve the low electrical conductivity properties of pure PEDOT:PSS, in the present invention, PSS is minimally mixed. Preferably, the poly(3,4-ethylenedioxythiophene) (PEDOT):polystyrenesulfonate (PSS) is PEDOT and PSS may be mixed in a weight ratio of 1:1 to 1:1.8, more preferably 1:1.5 to 1:1.7 by weight, and most preferably 1:1.6 by weight. In particular, if the mixing ratio of the PSS is less than 1 weight ratio, the hydrophilicity may be lowered and it may not be well dispersed in water.

The transparent electrode includes a polyvinylidene fluoride-based polymer nanofiber web and a conductive polymer in a weight ratio of 1:0.01 to 1:1, preferably 1:0.01 to 1:0.05, more preferably 1:0.01 to 1:0.02 It may be a mixture by weight. At this time, if the content of the conductive polymer is less than 0.01 weight ratio, the excellent electrical conductivity effect of the transparent electrode cannot be expected. Conversely, if the content exceeds 1 weight ratio, the flexibility of the transparent electrode is lowered, so that it may be difficult to apply as a clothing product.

The transparent electrode may have a light transmittance of 70 to 84% in a visible light region of 400 to 700 nm, preferably 81 to 84%.

Meanwhile, the present invention provides a solar cell fiber including the transparent electrode.

The transparent electrode included in the solar cell fiber (Photovoltaic Textiles) may serve to collect solar light and transmit it to the inside, and expand the contact area between the electrode and the photoactive layer to allow electricity to flow well.

In addition, the present invention provides a product including the solar cell fiber.

The product may be manufactured as a body of clothes, automobiles, ships, aircraft, or cases of electronic products including the solar cell fibers. In addition, as the final product can be manufactured in a bendable form as needed, it has the advantage of being applicable to a variety of ranges.

In addition, the present invention comprises the steps of preparing a mixed solution by mixing an aqueous dispersion of a conductive polymer and an organic solvent; coating the mixed solution on the polyvinylidene fluoride-based polymer nanofiber web; and manufacturing a transparent electrode by drying the matrix polymer nanofiber web coated with the mixed solution;

The conductive polymer aqueous dispersion includes polythiophene, polyaniline, PANI, polypyrrole, PPy, polyacetylene, polydiacetylene, and polythiophenevinylene. ), polyfluorene and poly(3,4-ethylenedioxythiophene) (PEDOT): may include at least one selected from the group consisting of polystyrene sulfonate (PSS), preferably PEDOT: PSS may include

The organic solvent may be dimethyl sulfoxide (DMSO). The dimethyl sulfoxide solvent may further improve the electrical conductivity of the aqueous dispersion of the conductive polymer and improve transparency.

In particular, when the PEDOT:PSS is included as the aqueous dispersion of the conductive polymer, the DMSO solvent may be mixed as a secondary dopant in order to solve the low electrical conductivity characteristics of the existing pure PEDOT:PSS. In this case, the DMSO solvent may penetrate between the positively charged PEDOT and negatively charged PSS bonds to perform charge screening. Due to this, the electrostatic attraction between the PEDOT and the PSS is reduced to separate from each other, and the contact between the PEDOT particles is increased to facilitate the movement of charges. In addition, when the PEDOT:PSS aqueous dispersion and the DMSO solvent are mixed, the structure rearrangement and shape change of the PEDOT:PSS may occur, thereby increasing electrical conductivity. In addition, in this mixing process, PSS is partially extracted from the surface of the PEDOT:PSS, and as a result, the contact between the PEDOT particles is increased, so that an electric charge can flow well. In this case, as a part of the PSS is extracted, the transparency of the transparent electrode may be improved.

The mixed solution contains the aqueous dispersion of the conductive polymer and the organic solvent in a volume ratio of 6:4 to 3:7, preferably 5:5 to 3:7 by volume, more preferably 4:6 to 3:7 by volume, most preferably It may be mixed in a 3:7 volume ratio. In particular, if the content of the organic solvent is less than 4 volume ratio, the light transmittance of the transparent electrode may be remarkably low. On the contrary, if it exceeds 7 volume ratio, the conductive polymer particles are dropped due to the use of an excessive amount of the organic solvent, so that the electrical conductivity of the transparent electrode is sharp. may be significantly lowered, and thus the light transmittance may also be lowered.

The step of coating the mixed solution is a brush painting method, a spin coating method, a dip coating method, a dropping method, a spray coating method, an inkjet printing method ( inkjet printing), screen printing, and spotting may be performed by one selected from the group consisting of, preferably, brush painting. The brush painting method has the advantage that the thickness can be adjusted from several tens to several hundreds of nanometers, and the process is easy regardless of the base material.

In the step of manufacturing the transparent electrode, drying may be performed at 50 to 100° C. for 1 minute to 2 hours. Preferably, it may be carried out at 68 to 72° C. for 5 minutes to 15 minutes, and most preferably at 70° C. for 10 minutes.

In particular, in the transparent electrode, the PEDOT:PSS aqueous dispersion is mixed with a dimethyl sulfoxide (DMSO) solvent, and crystallinity is controlled by strong interaction between the PEDOT:PSS aqueous dispersion and the DMSO solvent only when a specific volume ratio is satisfied. The light transmittance can be improved, and at this time, as a result of ^{FT -} IR analysis, the first α ^- form crystal peak, the second 2 An α-form crystal peak and a β-form crystal peak can be seen.

For these crystal peaks, preferably, the absorption intensity ratio of (first α-form crystal peak)/(second α-form crystal peak) is 0.9 to 1.2, and the (second α-form crystal peak)/(β-form) The absorption intensity ratio of the crystal peak) may be 1.4 to 1.8, and the absorption intensity ratio of the (β-form crystal peak)/(the first α-form crystal peak) may be 0.5 to 0.7.

When the transparent electrode shows these crystal peaks and absorption intensity ratios in the FT-IR analysis result, although not explicitly described in the Examples or Comparative Examples, there is an advantage in that the transparent electrode has excellent properties of transparency, flexibility, and light resistance.

In particular, although not explicitly described in the following Examples or Comparative Examples, in the method for manufacturing the transparent electrode for solar cell fiber according to the present invention, the transparent electrode prepared under the following 7 conditions was applied to the solar cell fiber. Then, the physical properties of light resistance, durability, thermal stability and flexibility were evaluated by a conventional method.

As a result, it was confirmed that, unlike in other conditions and in other numerical ranges, when all of the following conditions were satisfied, not only had excellent light transmittance, but also the physical properties of light tomorrow, durability, thermal stability and flexibility all showed uniformly excellent values.

① The polyvinylidene fluoride-based polymer nanofiber web has an average fiber diameter of 200 to 500 nm, and a cotton weight of 3 to 5 g/m ² , ② The polyvinylidene fluoride-based polymer is polyvinylidene fluoride and ③ the conductive polymer aqueous dispersion is poly(3,4-ethylenedioxythiophene) (PEDOT):polystyrenesulfonate (PSS) in which PEDOT and PSS are mixed in a weight ratio of 1:1.5 to 1:1.7, ④ the organic The solvent is dimethyl sulfoxide (DMSO), ⑤ the mixed solution is a mixture of a conductive polymer aqueous dispersion and an organic solvent in a volume ratio of 4:6 to 3:7, ⑥ coating the mixed solution is brush painting It is carried out by brush painting, and ⑦ drying in the step of manufacturing the transparent electrode may be performed at 68 to 72° C. for 5 to 15 minutes.

However, when any one of the above seven conditions is not satisfied, flexibility is remarkably reduced, or excellent physical properties in durability, thermal stability, and light resistance are not uniformly exhibited.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited by the following examples.

Example 1: Preparation of transparent electrode

(1) material

The base textile used in the present invention is described in Pardam, s.r.o. Ltd. (Czech Republic) purchased PVDF nanofiber web (Poly (Vinylidene) Fluoride Nanofiber Web) was used without additional treatment. The physical properties of the PVDF nanofiber web used are shown in Table 1 below.

In addition, in order to impart electrical conductivity to the PVDF nanofiber web, an aqueous dispersion of PEDOT:PSS dispersed in water at 1.3% by weight was used, and was purchased from Sigma-Aldrich (United States of America). The physical properties of the PEDOT:PSS aqueous dispersion are shown in Table 2 below. In addition, in order to improve the electrical conductivity and light transmittance of the sample, a 99.9% DMSO (Dimethyl Sulfoxide) solution purchased from Duksan Pure Chemicals (Republic of Korea) was diluted to 80% by volume in distilled water and used.

(2) PEDOT: PSS/DMSO mixed solution preparation

1 is a diagram schematically showing a method for preparing a PEDOT:PSS/DMSO mixed solution. First, a PEDOT:PSS aqueous dispersion dispersed in water at 1.3% by weight and a DMSO solution diluted to 80% by volume were mixed in nine volume ratios (10:0, 9:1, 8:2, 7:3, 6:4, 5: 5, 4:6, 3:7, 2:8) in a vial. At this time, the sample treated with the PEDOT:PSS/DMSO solution of 1:9 volume ratio through the pre-test was partially damaged and was excluded from this experiment. After that, the vial in which the PEDOT:PSS and DMSO solutions were mixed was subjected to magnetic stirring at room temperature at 150 rpm for 30 minutes to prepare nine uniformly mixed PEDOT:PSS/DMSO mixed solutions.

(3) Transparent electrode fabrication

2 shows PEDOT:PSS mixed in 9 volume ratios (10:0, 9:1, 8:2, 7:3, 6:4, 5:5, 4:6, 3:7, 2:8) A method for preparing a transparent electrode sample using a /DMSO mixed solution is schematically shown. First, a PVDF nanofiber web was prepared with a size of (2 x 2) cm ² , and 0.05 ml of a PEDOT:PSS/DMSO mixed solution was treated thereon using a brush-painting technique, respectively. Thereafter, it was dried for 10 minutes in an atmospheric condition in a vacuum dryer (OV-11 Vacuum Oven, JEIO Tech. co., LTD, Republic of Korea) set at a temperature of 70 °C. Finally, a total of nine P10D0, P9D1, P8D2, P7D3, P6D4, P5D5, P4D6, P3D7, and P2D8 transparent electrode samples were prepared. The sample names and treatment conditions of the prepared samples are shown in Table 3 below. The prepared transparent electrode was mixed with a PVDF nanofiber web and a conductive polymer in a weight ratio of 1: 0.01 to 0.02.

Example 2: Manufacturing of photovoltaic textile

3 is a view schematically showing a method of manufacturing a photovoltaic fiber. For manufacturing, a dye-sensitized solar cell kit purchased from Arbor Scientific (United States of America) was used. As the prepared materials, two nanofiber web-based transparent electrodes (2 x 2) cm ² , pencil, blueberry, a vegetable dye, TiO ₂ paste, and iodine-iodide electrolyte (Iodide/Triiodide Electrolyte) solution were prepared. At this time, the P3D7 transparent electrode sample showing the best performance index in the present invention was used for the photovoltaic fiber.

First, 0.05 g of TiO ₂ Paste was treated on one of the two P3D7 samples, and dried for 5 minutes on a hot plate set at a temperature of 70 ℃. Then, the TiO ₂ Paste-treated sample was immersed in mashed blueberries for 10 minutes to prepare a first electrode.

Then, the remaining P3D7 samples were carbon-treated using a pencil. Then, 0.05 g of an electrolyte, iodine-potassium iodide solution, was treated on the carbon-treated sample to prepare a second electrode. Finally, the TiO ₂ /dye-treated first electrode and the carbon/electrolyte-treated second electrode were alternately pressed against each other to complete the solar cell fiber.

Comparative Example 1

For comparison, a dye-sensitized solar cell was prepared in the same manner as in Example 2 using FTO, which is a conventional transparent electrode.

Experimental Example 1-1: Evaluation of sheet resistance of transparent electrode

In order to compare the electrical properties according to the mixing ratio of PEDOT:PSS and DMSO for the transparent electrode prepared in Example 1, sheet resistance (Ω/sq, Sheet Resistance) was measured. The sample was prepared in the size of (2 x 2) cm ² and measured at the contact surface, and a 4 Point Probe sheet resistance measuring instrument CMT-SR1000N (AIT, Republic of Korea) was used. At this time, for reliability of the data, the average value was calculated after repeated measurement 7 times. The results are shown in Figure 4 and Table 4.

4 is a graph showing the sheet resistance measurement results according to the volume ratio of PEDOT: PSS/DMSO mixed solution for the transparent electrodes (P10D0, P9D1, P8D2, P7D3, P6D4, P5D5, P4D6, P3D7, P2D8) prepared in Example 1; am.

According to the results of FIGS. 4 and 4, the sheet resistance values of P10D0, P9D1, P8D2, P7D3, P6D4, P5D5, P4D6, P3D7, and P2D8, which are nine samples having different mixing ratios of PEDOT:PSS and DMSO, were measured. . The P10D0 sample treated with only PEDOT:PSS without DMSO had a sheet resistance value of 980,114 Ω/sq, and the samples treated with DMSO (P9D1, P8D2, P7D3, P6D4, P5D5, P4D6, P3D7, P2D8) had a sheet resistance of 348. It had a sheet resistance value in the range of ~ 4,278 Ω/sq. Through this, it was confirmed that the sheet resistance value showed a difference between a minimum of 229 times and a maximum of 2,816 times depending on the presence or absence of DMSO treatment. In addition, it was found that the electrical properties were improved when the PEDOT:PSS aqueous dispersion and DMSO solvent were mixed and treated. This is because, as the DMSO solvent was added to the PEDOT:PSS aqueous dispersion, some of the insulator PSS was extracted, and the contact between the conductive polymer PEDOT particles increased.

Comparing the sheet resistance values of the samples treated with the PEDOT:PSS/DMSO mixture (P9D1, P8D2, P7D3, P6D4, P5D5, P4D6, P3D7, P2D8), the P9D1 sample showed the lowest sheet resistance value of 348 Ω/sq. , P2D8 sample showed the highest sheet resistance value of 4,278 Ω/sq. That is, the sheet resistance value gradually increased as the DMSO ratio increased. Through this, it can be seen that the electrical conductivity is improved when the DMSO solvent is added to the PEDOT:PSS aqueous dispersion, but when the ratio of DMSO is too high, the distance between the PEDOT particles increases and the electrical conductivity is rather reduced. On the other hand, the sheet resistance value increased rapidly between the P3D7 and P2D8 samples, and the sample in which the ratio of PEDOT:PSS to DMSO was 2:8 showed the lowest electrical conductivity. Accordingly, it was found that the P9D1 sample having the lowest DMSO ratio with a mixing ratio of PEDOT:PSS and DMSO of 9:1 has the best electrical conductivity.

Experimental Example 1-2: Evaluation of light transmittance of transparent electrode

In order to examine the change in light transmittance according to the mixing ratio of PEDOT:PSS and DMSO for the transparent electrode prepared in Example 1, the light transmittance in the visible light (400-700 nm) region was measured, and the maximum light transmittance and The average light transmittance was derived. For the measurement, an untreated PVDF nanofiber web sample and a sample treated with PEDOT:PSS/DMSO were prepared in a size of 2 x 2 cm ² , and the base line was set to air, and measurement was performed. The instrument used for the measurements was a Cary 5000 UV-Vis-NIR Spectrophotometer (Agilent, United States of America). The light transmittance was measured in the visible region (400 ~ 700 nm). The results are shown in Figure 5 and Table 5.

Figure 5 shows the untreated PVDF nanofiber web sample and the transparent electrode (P10D0, P9D1, P8D2, P7D3, P6D4, P5D5, P4D6, P3D7, P2D8) prepared in Example 1 in the volume ratio of PEDOT:PSS/DMSO mixed solution It is a graph showing the light transmittance spectrum measurement result.

According to the results of Figures 5 and 5, the untreated PVDF nanofiber web sample showed a maximum light transmittance of 6.22%, and the P10D0 sample treated with PEDOT:PSS only showed a maximum light transmittance of 5.70%, the untreated PVDF nanofiber web It was confirmed to have a light transmittance similar to that of

On the other hand, the samples treated with PEDOT:PSS/DMSO solution (P9D1, P8D2, P7D3, P6D4, P5D5, P4D6, P3D7, P2D8) showed a maximum light transmittance in the range of 15.01 ~ 85.21%. Through this, it was found that the sample treated with the PEDOT:PSS/DMSO mixed solution showed better optical properties than the sample treated with only PEDOT:PSS. This is because the crystal structure in the PVDF nanofiber was deformed by the DMSO solvent treatment, and the boundary between the crystalline region and the amorphous region was reduced.

In particular, the ratio of PEDOT:PSS to DMSO was 9:1, and the P9D1 sample containing the least DMSO showed a maximum light transmittance of 15.01%, and the P2D8 sample containing the most DMSO at a 2:8 ratio showed a maximum light transmittance of 85.21%. showed transmittance. Through this, it can be confirmed that as the DMSO mixing ratio increases, the light transmittance of the sample also increases. Therefore, the P2D8 sample with the highest DMSO mixing ratio showed the best light transmittance.

Experimental Example 1-3: Surface microstructure analysis and thickness measurement of transparent electrodes

In order to observe the surface microstructure of the PVDF nanofiber web according to the mixing ratio of PEDOT:PSS and DMSO for the transparent electrode prepared in Example 1, a scanning electron microscope (Field Emission Scanning Electron Microscope, FE-SEM) photographing was performed. carried out. Through FE-SEM imaging, the surface microstructure change before and after PEDOT:PSS and DMSO treatment on PVDF nanofiber web samples, and the surface microstructure change according to the PEDOT:PSS and DMSO mixing ratio were analyzed. For analysis (1 x 1) cm ² A sample was prepared and photographed at 2,000 magnification using a JSM-7610F Plus (Jeol Ltd, United States of America) instrument.

In order to compare the thickness change of the sample before and after PEDOT:PSS and DMSO treatment on the PVDF nanofiber web sample, a Surface Profiler analysis was performed. For analysis, a sample was prepared in a size of (1 x 1) cm ² , and a DektakXT Stylus Profiler (Bruker, United States of America) instrument was used. At this time, the measurement was repeated three times to derive the average value. In addition, in order to observe the surface particle shape and surface roughness of the PVDF nanofiber web sample before and after PEDOT:PSS and DMSO treatment, an atomic force microscope (AFM) analysis was performed. For analysis, a sample was prepared in the size of (1 x 1) cm ² and an NX-10 (Park Systems, Republic of Korea) instrument was used. The resolution of the XY scanner of the measuring instrument was 0.05 nm, and the scan range of the Z scanner was 15 μm, resolution is 0.015 nm. AFM imaging of the sample was performed in the range of 2 x 2 μm ² , and the surface roughness (R _a ) of the photographed area was measured. The results are shown in FIGS. 6 to 8 .

6 is an FE-SEM image of an untreated PVDF nanofiber web. According to the result of FIG. 6, in the case of the surface microstructure of the untreated PVDF nanofiber web, it was confirmed that numerous nanofibers were irregularly entangled while forming small pores.

7 is a PEDOT for the transparent electrodes (P10D0, P9D1, P8D2, P7D3, P6D4, P5D5, P4D6, P3D7, P2D8) prepared in Example 1: PEDOT: PSS / DMSO surface of the PVDF nanofiber web according to the volume ratio of the mixed solution This is an FE-SEM image of the microstructure.

According to the result of FIG. 7, looking at the surface of the P10D0 sample not treated with DMSO, PEDOT:PSS was adsorbed on the surface of the PVDF nanofiber, and the thickness of the nanofiber became thick, and it was found that the pores were filled. Through this, it was confirmed that PEDOT:PSS was coated on the PVDF nanofiber web, which shows that electrical conductivity was successfully imparted to the PVDF nanofiber web sample.

On the other hand, in the case of P9D1, P8D2, P7D3, P6D4, P5D5, P4D6, P3D7, and P2D8 samples treated with PEDOT:PSS/DMSO mixed solution, it was observed that the conductive solution was evenly treated on the PVDF nanofiber web. In addition, it was confirmed that the surface of the sample gradually became smoother as the DMSO ratio increased. In particular, nanofiber strands and pores were observed on the surfaces of samples P10D0, P9D1, and P8D2, but in samples P7D3, P6D4, P5D5, P4D6, P3D7, and P2D8, nanofiber strands and pores were not observed at all, and all had a flat surface. In particular, the pores formed between the fibers and the uneven structure of the surface cause diffuse reflection. For this reason, it is considered that the light transmittance of the P7D3, P6D4, P5D5, P4D6, P3D7, and P2D8 samples increased. 6, the P10D0, P9D1, and P8D2 samples showed a low light transmittance with a maximum light transmittance of 5.70 to 25.59%, whereas the P7D3, P6D4, P5D5, P4D6, P3D7, and P2D8 samples had a maximum light transmittance of 66.20 to 85.21. %, which is supported by the sharp increase in results.

8 is a graph showing the measurement of the thickness of the untreated PVDF nanofiber web sample and the P10D0 sample, P9D1 sample, P2D8 sample, and P3D7 sample of Example 1 of the present invention. 8, in the case of the untreated PVDF nanofiber web sample, the thickness was the thickest at 31.37 μm, and the thickness was 11.4, 9.49, 2.93 and 2.12, respectively, in the order of P10D0 sample > P9D1 sample > P2D8 sample > P3D7 sample. It was confirmed that it was μm.

A Surface Profiler analysis was performed to examine the thickness change before and after the PVDF nanofiber web sample was treated with a mixed solution of PEDOT:PSS and DMSO. In addition, AFM analysis was performed to examine the changes in the surface particle shape and surface roughness (Roughness, Ra) before and after PEDOT _: PSS and DMSO were treated on the PVDF nanofiber web sample. At this time, an untreated PVDF nanofiber web sample, a P10D0 sample treated with PEDOT:PSS only, a P9D1 sample having the best electrical conductivity, a P2D8 sample having the lowest electrical conductivity, and a P3D7 sample having the best performance index as a transparent electrode were analyzed. .

9 is an untreated PVDF nanofiber web sample and the PEDOT:PSS-treated P10D0 sample of Example 1, the P9D1 sample having the best electrical conductivity, the P2D8 sample having the lowest electrical conductivity, and the best performance index as a transparent electrode Eggplant is an AFM image of each thickness, surface particle shape, and surface roughness of the P3D7 sample.

According to the result of FIG. 9, the thickness of the sample affects the light transmittance, and as the thickness decreases, the light transmittance increases. The P9D1 sample and the P2D8 sample mixed with DMSO showing the maximum light transmittance of 15.01% and 85.21% had relatively thin thicknesses, and it was found that the thinner the thickness, the better the light transmittance.

In addition, when looking at the untreated PVDF nanofiber web sample, PVDF nanofiber strands could be clearly identified. In the AFM image, the light colored area means PEDOT particles, and the black area means PSS particles. In the P10D0 sample treated with only PEDOT:PSS, PEDOT and PSS particles were observed, confirming that PEDOT:PSS was properly treated on the PVDF nanofiber web. On the other hand, in the case of the P9D1 and P2D8 samples treated with the PEDOT:PSS/DMSO mixed solution, the PSS area gradually decreased, and the PEDOT particles changed from a coiled structure to a linear structure connected to each other. This is because PSS, which is an insulator, was partially extracted by DMSO, and the phase changed as the contact characteristics of PEDOT improved. Also, looking at the P2D8 sample in which DMSO was mixed in the highest ratio, it was confirmed that the size of the PEDOT region was reduced. It was found that too much DMSO was treated and the conductive polymer PEDOT particles were also removed.

Meanwhile, as a result of measuring the electrical conductivity of each sample, the P10D0 sample treated with only the PEDOT:PSS aqueous dispersion showed the lowest electrical conductivity at 980,114 Ω/sq, and the P9D1 sample mixed with DMSO at the lowest ratio was 348 Ω/sq. Electrical conductivity is improved. This is because the phase of PEDOT particles was changed and contact properties were improved as PSS, which is a non-conductor, was partially extracted by DMSO. In addition, the P2D8 sample mixed with DMSO at the highest ratio showed a rather decreased electrical conductivity to 4,278 Ω/sq, because too much DMSO was treated and even the conductive polymer PEDOT particles were dropped. It can be seen that the surface roughness is closely related to the light transmittance, since a lot of diffuse reflection occurs in the sample with an uneven surface.

Looking at the surface roughness in the result of FIG. 9, the PVDF nanofiber web sample showed a surface roughness of 110.614 nm. Also, in the case of P10D0, P9D1, and P2D8 samples treated with PEDOT:PSS and DMSO, surface roughness of 5.924 ~ 8.870 nm was shown. Through this, it was confirmed that the PVDF nanofiber web sample had a surface roughness of 10 times or more than that of the sample treated with a mixed solution of PEDOT:PSS/DMSO. It was found that the surface roughness was reduced because the fine hairs on the nanofiber surface were compressed during the process of solution treatment on the PVDF nanofiber web.

Specifically, the P10D0 sample treated with PEDOT:PSS only showed a surface roughness of 6.924 nm, the P9D1 sample treated with the lowest DMSO ratio was 6.485 nm, and the P2D8 sample treated with the highest DMSO ratio showed a surface roughness of 5.924 nm. Through this, it was found that when DMSO was treated at a high ratio, it showed a lower surface roughness. Here, the P10D0 sample with the highest surface roughness showed a maximum light transmittance of 5.70%, and the P2D8 sample with the lowest surface roughness showed a maximum light transmittance of 85.21%, indicating that the light transmittance increased as the surface roughness decreased.

Experimental Example 1-4: FT-IR analysis of transparent electrode

In order to analyze the chemical structure change of the sample according to the mixing ratio of PEDOT:PSS and DMSO for the transparent electrode prepared in Example 1, Fourier Transform Infrared Spectrometer (FT-IR) analysis was performed. The instrument used for the analysis was Vertex 70 (Bruker, United States of America), the analysis range of the instrument was 8,000 to 350 cm ^-1 , the resolution was 0.4 cm ^-1 , and the photosensitivity was 11,871 to 2,200 cm ^-1 . For measurement, a sample was prepared in the size of (1 x 1) cm ² , and analysis was performed by the attenuated total reflection (ATR) method. At this time, the PEDOT:PSS aqueous dispersion was dried at room temperature for 24 hours and analyzed. By confirming the presence of functional groups of PVDF and PEDOT:PSS in the sample through FT-IR analysis, it was confirmed whether the PEDOT:PSS/DMSO solution was properly treated on the PVDF nanofiber web. In addition, the chemical structure change according to the ratio of PEDOT:PSS and DMSO was analyzed. The results are shown in FIGS. 10 to 12 .

10 shows the results of FT-IR analysis of the untreated PVDF nanofiber web.

According to the results of FIG. 10, in the untreated PVDF nanofiber web sample, α-type crystal peaks were observed in the vicinity of 876 cm ^-1 , 1180 cm ^-1 , and β-type crystal peaks were 840 cm ^-1 , 1072 cm ^-1 , It was observed in the vicinity of 1400 cm ^-1 to confirm the chemical structure of the PVDF nanofiber web.

11 shows the results of FT-IR analysis of PEDOT:PSS aqueous dispersion.

According to the result of FIG. 11, in the case of the PEDOT:PSS aqueous dispersion, C=C Stretching at 1515 cm ^-1 and 1640 cm ^-1 , CC Stretching at 1292 cm ^-1 and 1340 cm ^-1 , 704 cm ^-1 , CS stretching at around 845 cm ^-1 and CO stretching peaks at around 1144 cm ^-1 were observed. The observed C=C stretching, CC stretching, and CS stretching are functional groups corresponding to the thiophene ring of PEDOT, and CO stretching is also a functional group related to PEDOT. In addition, S=O Stretching and SO Stretching peaks corresponding to PSS were observed near 1055 cm ^-1 and 1121 cm ^-1 , respectively.

12 shows the chemical structure changes of each sample according to the volume ratio of PEDOT:PSS/DMSO mixed solution for the transparent electrodes (P10D0, P9D1, P8D2, P7D3, P6D4, P5D5, P4D6, P3D7, P2D8) prepared in Example 1; is the FT-IR analysis result showing .

According to the results of FIG. ¹² , in the case of the ^{P10D0 sample} treated only with ^PEDOT : ^PSS , the PVDF nanofiber web and A peak appeared in PEDOT:PSS, which means that PEDOT:PSS was properly treated on the surface of the PVDF nanofiber web. In addition, it was confirmed that the peak in the vicinity of 1121 cm ^-1 corresponding to SO stretching of PSS gradually disappeared as the PEDOT:PSS ratio decreased and the DMSO ratio increased. Through this, it was found that the PSS layer, which is an insulator, was extracted by DMSO. In addition, it was confirmed that the peaks near 1292 cm ^-1 and 1515 cm ^-1 corresponding to CC Stretching and C=C Stretching, which are functional groups of PEDOT, also disappeared as the proportion of DMSO increased. This means that an excessively large amount of DMSO was treated and even PEDOT, a conductive polymer, was extracted, and as the DMSO ratio increased, the electrical conductivity of the sample decreased.

As shown in the previous electrical conductivity measurement results, the P2D8 sample treated with the highest DMSO ratio showed low electrical conductivity of 4,278 Ω/sq, and the P9D1 sample treated with the lowest DMSO ratio was 348 Ω/sq. It was the same as the result showing high electrical conductivity. As the ratio of PEDOT:PSS decreased and the ratio of DMSO increased, the intensity of the α-type crystal peak corresponding to the PVDF nanofiber web gradually increased around 873 cm ^-1 and 1180 cm ^-1 . This means that the structure in the PVDF nanofibers was modified by DMSO treatment. In particular, as the amorphous α-type crystal increases, the boundary between the crystalline region and the amorphous region decreases and diffuse reflection decreases. As a result, the light transmittance increases as the DMSO mixing ratio increases. As shown in the previous light transmittance measurement results, the P9D1 sample treated with the lowest DMSO ratio showed a maximum light transmittance of 14.78%, and the P2D8 sample treated with the highest DMSO ratio showed a maximum light transmittance of 85.21%. Same as result.

Experimental Example 1-5: Analysis of figure of merit of transparent electrode

Among the mixing ratios of PEDOT:PSS and DMSO for the transparent electrode prepared in Example 1, in order to derive the mixing ratio condition showing the best performance as a transparent electrode, the figure of merit (FOM: Figure of) defined by Haacke (1976) Merit, ϕ _TC ) was calculated. The figure of merit calculation formula is as follows, where T _av is the average light transmittance at a wavelength of 400 to 700 nm, and R _sh is the average sheet resistance value. The results are shown in FIG. 13 and Table 6.

[Performance Index Calculation Formula]

φ _TC = T _av ^1D / R _sh

13 shows the average sheet resistance value of each sample according to the volume ratio of the PEDOT:PSS/DMSO mixed solution for the transparent electrodes (P10D0, P9D1, P8D2, P7D3, P6D4, P5D5, P4D6, P3D7, P2D8) prepared in Example 1; (R _sh ) and average light transmittance (T _av ) are used to show the result of calculating the figure of merit (φ _TC ).

According to the results of FIG. 13 and Table 6, the P10D0, P9D1, and P8D2 samples showing a low average light transmittance of about 25% or less showed a figure of merit close to zero. On the other hand, samples (P7D3, P6D4, P5D5, P4D6, P3D7, P2D8) exhibiting a high average light transmittance of about 65% or more showed an excellent figure of merit in the range of 0.027 ~ 0.104 x 10 ^-3 Ω ^-1 . Through this, it was confirmed that the average light transmittance had a large effect on the figure of merit.

Looking at each sample in detail, the figures of merit of the P7D3, P6D4, P5D5, P4D6, P3D7, and P2D8 samples, which showed excellent average light transmittance of about 65% or more, were 0.027 x 10 ^-3 Ω ^-1 , 0.053 x 10 ^-3 Ω ^-1 , respectively. It is 0.050 x 10 ^-3 Ω ^-1 , 0.095 x 10 ^-3 Ω ^-1 , 0.104 x 10 ^-3 Ω ^-1 , 0.046 x 10 ^-3 Ω ^-1 , and it can be seen that the figure of merit increases as the average light transmittance increases. could However, the P5D5 sample showed a slightly lower figure of merit compared to the P6D4 sample, which slightly increased the average light transmittance while the sheet resistance value was greatly increased. It was found that the P2D8 sample showed a lower figure of merit than the P3D7 sample for the same reason. Finally, considering both the electrical and optical properties of the sample, the P3D7 sample showed the highest figure of merit (0.104 x 10 ^-3 Ω ^-1 ). Therefore, it was confirmed that the mixing ratio of PEDOT:PSS and DMSO, which had the best performance as a transparent electrode, was 3:7.

Experimental Example 2: Evaluation of Energy Conversion Efficiency of Solar Cell Fibers

In order to confirm whether it is applicable as a solar cell fiber to the transparent electrode (P3D7) prepared in Example 1 based on PEDOT: PSS/DMSO-treated PVDF nanofiber web, a solar cell fiber was prepared and energy conversion efficiency (Power Conversion Efficiency) , η) were evaluated and compared with a dye-sensitized solar cell to which a conventional transparent electrode (FTO) was applied. In order to confirm the current-voltage (IV) characteristics of the manufactured solar cell, a 450W Solar Simulator (Newport, United States of America) device, which is an artificial sunlight irradiation device, was used. At this time, measurements were made in the same AM (Air Mass) 1.5 environment as the Earth incident light conditions, and a light source of 100 mW/cm ² was used. Current-voltage characteristics were analyzed using a Keithley SMU 2400 instrument. The results are shown in FIG. 14 and Table 7.

14 is a result of measuring the current-voltage characteristics of the conventional FTO transparent electrode-based dye-sensitized solar cell and the solar cell fiber using the transparent electrode (P3D7) prepared in Example 1.

14 and Table 7 are the results of calculating the energy conversion efficiency (PCE, η) through the current-voltage characteristics, and the FTO-based solar cell showed an efficiency of 1.4 x 10 ^-3 %, and the transparency of Example 1 The solar cell fiber using the electrode (P3D7 sample) showed an efficiency of 0.1 x 10 ^-3 %. Through this, it was confirmed that the solar cell fiber using the transparent electrode (P3D7 sample) of Example 1 had a photoelectric effect.

In addition, looking at the filling factor, which is a factor determining the maximum output in the solar cell, the FTO-based solar cell was 27.448%, and the solar cell fiber using the transparent electrode (P3D7 sample) of Example 1 showed a higher result value of 36.552%. . This means that when the short-circuit current and open-circuit voltage are improved by improving the electrical characteristics of the transparent electrode (P3D7 sample) of Example 1, the solar cell fiber can have higher energy conversion efficiency than the conventional FTO-based solar cell. do.

Through this, it was confirmed that the transparent electrode (P3D7 sample) of Example 1 can be used as a transparent electrode for solar cell fibers. In addition, it was confirmed that when the electrical characteristics of the transparent electrode (P3D7 sample) of Example 1 were improved, it could have better energy conversion efficiency than the FTO-based solar cell.

Claims (18)

polyvinylidene fluoride-based polymer nanofiber web; and
A transparent electrode for solar cell fibers comprising; a conductive polymer bonded to the surface of the polyvinylidene fluoride-based polymer nanofiber web and the surface of the fibers inside the web,
As a result of FT-IR analysis, the transparent electrode showed a first α-form crystal peak and a second α-form crystal peak in the wavelength range of ① 872 to 874 cm ^-1 , ② 1179 to 1181 cm ^-1 and ③ 1291 to 1293 cm ^-1 , respectively. and a β-form crystal peak,
The absorption intensity ratio of (first α-form crystal peak)/(second α-form crystal peak) is 0.9 to 1.2, and the absorption intensity ratio of (second α-form crystal peak)/(β-form crystal peak) is 1.4 to 1.8, and the absorption intensity ratio of (β-type crystal peak)/(first α-type crystal peak) is 0.5 to 0.7 for a transparent electrode for solar cell fibers.
According to claim 1,
The polyvinylidene fluoride-based polymer nanofiber web has an average fiber diameter of 100 to 800 nm, and a surface weight of 1 to 30 g/m ² A transparent electrode for solar cell fibers.
According to claim 1,
The polyvinylidene fluoride-based polymer is polyvinylidene fluoride (poly(vinylidene fluoride)), poly(vinylidene fluoride-co-hexafluoropropylene) (poly(vinylidene fluoride-co-hexafluoropropylene)), poly( consisting of poly(vinylidene fluoride-co-tetrafluoroethylene) and poly(vinylidenefluoride-co-trifluoroethylene) A transparent electrode for a solar cell fiber that is at least one selected from the group.
According to claim 1,
The conductive polymer includes polythiophene, polyaniline (PANI), polypyrrole (PPy), polyacetylene, polydiacetylene, polythiophenevinylene), A transparent electrode for a solar cell fiber that is at least one selected from the group consisting of polyfluorene and poly(3,4-ethylenedioxythiophene) (PEDOT):polystyrenesulfonate (PSS).
5. The method of claim 4,
The poly(3,4-ethylenedioxythiophene) (PEDOT):polystyrenesulfonate (PSS) is a transparent electrode for solar cell fibers in which PEDOT and PSS are mixed in a weight ratio of 1:1 to 1:1.8.
According to claim 1,
The transparent electrode is a transparent electrode for solar cell fibers in which a polyvinylidene fluoride-based polymer nanofiber web and a conductive polymer are mixed in a weight ratio of 1:0.01 to 1:1.
According to claim 1,
The transparent electrode is a transparent electrode for a solar cell fiber having a light transmittance of 70 to 84% in a visible light region of 400 to 700 nm.
A solar cell fiber comprising the transparent electrode of any one of claims 1 to 7.
A product comprising the solar cell fiber of claim 8 .
10. The method of claim 9,
The product is a product that is a case of clothing, automobiles, ships, aircraft bodies, or electronic products.
preparing a mixed solution by mixing a conductive polymer aqueous dispersion and an organic solvent;
coating the mixed solution on the surface of the polyvinylidene fluoride-based polymer nanofiber web and the surface of the fibers inside the web; and
manufacturing a transparent electrode by drying the polymer nanofiber web coated with the mixed solution;
including,
The method for producing a transparent electrode for a solar cell fiber is that the mixed solution is a mixture of an aqueous dispersion of a conductive polymer and an organic solvent in a volume ratio of 6:4 to 3:7.
12. The method of claim 11,
The conductive polymer aqueous dispersion includes polythiophene, polyaniline, PANI, polypyrrole, PPy, polyacetylene, polydiacetylene, and polythiophenevinylene. ), polyfluorene, and poly(3,4-ethylenedioxythiophene) (PEDOT): polystyrene sulfonate (PSS) manufacturing a transparent electrode for solar cell fibers comprising at least one selected from the group consisting of Way.
12. The method of claim 11,
The organic solvent is dimethyl sulfoxide (Dimethyl Sulfoxide, DMSO) is a method of manufacturing a transparent electrode for a solar cell fiber.
delete 12. The method of claim 11,
The step of coating the mixed solution is a brush painting method, a spin coating method, a dip coating method, a dropping method, a spray coating method, an inkjet printing method ( Inkjet printing), screen printing (screen printing), and a method of manufacturing a transparent electrode for a solar cell fiber to be carried out by one method selected from the group consisting of spotting (spotting).
12. The method of claim 11,
In the step of manufacturing the transparent electrode, drying is performed at 50 to 100° C. for 1 minute to 2 hours. A method for manufacturing a transparent electrode for a solar cell fiber.
12. The method of claim 11,
As a result of FT-IR analysis, the transparent electrode showed a first α-form crystal peak and a second α-form crystal peak in the wavelength range of ① 872 to 874 cm ^-1 , ② 1179 to 1181 cm ^-1 and ③ 1291 to 1293 cm ^-1 , respectively. and a β-form crystal peak,
The absorption intensity ratio of (first α-form crystal peak)/(second α-form crystal peak) is 0.9 to 1.2, and the absorption intensity ratio of (second α-form crystal peak)/(β-form crystal peak) is 1.4 to 1.8, and the absorption intensity ratio of (β-form crystal peak)/(first α-form crystal peak) is 0.5 to 0.7.
12. The method of claim 11,
The polyvinylidene fluoride-based polymer nanofiber web has an average fiber diameter of 200 to 500 nm, and a cotton weight of 3 to 5 g/m ² ,
The polyvinylidene fluoride-based polymer is polyvinylidene fluoride,
The conductive polymer aqueous dispersion is poly(3,4-ethylenedioxythiophene) (PEDOT):polystyrenesulfonate (PSS) in which PEDOT and PSS are mixed in a weight ratio of 1:1.5 to 1:1.7,
The organic solvent is dimethyl sulfoxide (Dimethyl Sulfoxide, DMSO),
The mixed solution is a mixture of a conductive polymer aqueous dispersion and an organic solvent in a volume ratio of 4:6 to 3:7,
The step of coating the mixed solution is performed by brush painting,
In the step of manufacturing the transparent electrode, drying is performed at 68 to 72° C. for 5 to 15 minutes.

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