TW201327864A - Array electrospinning for dye sensitized solar cells - Google Patents

Abstract

A method for making the electrodes for a dye sensitized solar cell is provided. In particular, the method utilizes the array electrospinning technique so that mass production of the dye sensitized solar cells can be achieved.

Description

Array electrospinning technology applied to dye-sensitized solar cells

A method of preparing an electrode for a dye-sensitized solar cell is disclosed.

Because dye sensitized solar cells have the advantages of simple process, easy mass production, and inexpensive materials, they have recently been regarded as new generation solar cells, and in recent years, photoelectric conversion efficiency has increased to 11.18%, and the cost is about It is 1/5~1/10 of the traditional tantalum substrate solar cell. Moreover, since the dye-sensitized solar cell is not affected by the sunlight angle, it absorbs sunlight for a long time, so the power generation at the same time is even better than that of the twin solar cell.

The dye-sensitized solar cell photoanode mainly utilizes titanium dioxide to absorb ultraviolet rays, and the titanium dioxide powder is coated on the conductive glass, sintered into a titanium dioxide layer, and the titanium dioxide layer absorbs ultraviolet rays and is converted into electrons, and the conductive glass transmits electrons to the battery. The system forms electric energy; because titanium dioxide only absorbs ultraviolet light, but ultraviolet light only accounts for 0.3% of all solar energy. To improve the utilization of solar energy, a special dye that absorbs visible light is coated on the titanium dioxide layer, and the dye absorbs visible light. After intensification, the intensified dye releases electrons into the titanium dioxide and returns itself to the ground state to increase the output of electrical energy. Since electrons need to pass such a long path, and electrons advance through the layers in a jump manner, the tightness between the layers affects the rate of electron movement, which affects the efficiency of the entire battery. .

On the other hand, the dye-sensitized solar cell counter electrode (cathode) needs to rapidly reduce the oxidant of the electrolyte in the dye-sensitized titanium dioxide solar cell to effectively carry out the reduction reaction of the dye titanium oxide, and thus an effective catalyst is required. Platinum catalysts are currently the most widely used, but their properties (such as kinetic constants, chemical stability and coating stability) vary greatly depending on the method of manufacture. Because platinum materials are very expensive, in recent years, alternative materials for electrodes have been studied. Although the efficiency cannot be higher than that of platinum, it can be used in combination with platinum to reduce the amount of platinum, thereby reducing costs. Carbon black and conductive polymer polyaniline.

In order to meet the performance of the dye-sensitized solar cell, the dye-sensitized solar cell photoanode film and the counter electrode film need to meet specific requirements, such as good thickness uniformity, strong adhesion, and good film formation. The dye-sensitized solar cell photoanodeitor titanium dioxide film and the platinum or carbon black counter electrode film are mostly formed by spin coating, electrophoresis, screen printing, and doctor blade forming, and then sintered. Titanium dioxide photoanode and platinum/carbon black counter electrode. However, the above-mentioned conventional techniques are difficult to satisfy the above requirements. For example, the titanium dioxide film prepared by the screen printing method has poor adhesion to the substrate and is easily peeled off. In addition, in the above-mentioned prior art, except for the screen printing method, the others are not suitable for the large-area mass production process, but the cost of the screen printing method is too high and does not meet economic benefits.

The electrospinning process utilizes the electric field driving force between the positive and negative electrodes to spin the nano-grade fiber. The raw material amount is relatively low. Generally, the voltage is pulled from the inside of the polymer droplet to the voltage of 10 to 50 kV. The surface makes the surface charges mutually exclusive. When the surface voltage of the droplet surface is more than a certain value, the surface tension of the liquid condensation can be overcome, and the electric field pulls the driving fluid through the spinning nozzle to reach the surface of the other electrode collecting cylinder, and the process variable can be adjusted to make the droplet become fast. The growing polymer is sprayed and the width is shrunk to nanometer size via a tight loop spiral path, and the interwoven fibers can be considered as an electrospun film layer. The main parameters affecting the performance of electrospun fibers are: polymer concentration, process voltage, curing distance (nozzle to wire device distance), solvent volatility and electrospinning speed. The higher the polymer concentration, the greater the viscosity and surface tension, the weaker the splitting ability of the droplets after leaving the nozzle, and the larger the diameter of the fibers. As the process voltage increases, the splitting ability of the droplets increases, and the resulting fibers become finer. After the polymer droplets are ejected through the nozzle, the polymer solidifies into fibers when the solvent evaporates, and the effect of the curing distance on the fiber diameter varies from device to device.

By using the electrospinning principle, in addition to making a titanium dioxide photoanode, it can also be used to form a counter electrode film, a colloidal electrolyte film, and a dye coloring, so that the entire dye-sensitized solar cell process can be completely electrostatically charged. Spinning technology is completed.

However, the simple electrospinning method may have a problem that the number of holes is too large and the arrangement is not tight. Therefore, a novel electrode preparation method for a dye-sensitized solar cell is required to prepare a good conductivity and a small number of holes. A closely packed fibrous membrane.

Therefore, there is still a need for a manufacturing method for preparing a dye-sensitized solar cell electrode having excellent performance, and industrially, a rapid continuous process can be performed to solve a large-area commercialization problem.

The object of the present invention is to prepare an anode electrode and a counter electrode for a dye-sensitized solar cell by an array type electrospinning technique (WE Teo at al.: Mohamed B. Bazbouz and George K. Stylios; WE Teo and S. Ramakrishna). .

An aspect of the invention provides a method for preparing a photoanode for a dye-sensitized solar cell, comprising the steps of: (1-1) preparing a titania colloid; (1-2) electrospinning the titania by an array electrospinning method a colloid on a substrate, wherein the substrate is placed on two equal-voltage collecting plates to form a titanium dioxide fiber film on the substrate; and (1-3) a titanium dioxide fiber film obtained by the sintering step (1-2) , a titanium dioxide photoanode is obtained.

Another aspect of the present invention provides a method of preparing a platinum counter electrode for a dye-sensitized solar cell, comprising the steps of: (2-1) preparing a platinum counter electrode electrowinning solution; (2-2) using an array of static electricity Spinning electrospinning the platinum electroplating solution onto a substrate, wherein the substrate is placed on two equal voltage collecting plates to form a platinum counter electrode fiber film on the substrate; and (2-3) The platinum-to-electrode fiber membrane obtained in the step (2-2) is sintered to obtain a platinum counter electrode.

Yet another aspect of the present invention provides a method of preparing a carbon black counter electrode for a dye-sensitized solar cell, comprising the steps of: (3-1) preparing a carbon black counter electrode electrowinning solution; (3-2) as an array Electrospinning electrospinning the carbon black counter electrospinning liquid onto a substrate, wherein the substrate is placed on two equal voltage collecting plates to form a carbon black counter electrode fiber membrane on the substrate; 3-3) The carbon black counter electrode fiber film obtained in the sintering step (3-2) is obtained to obtain a carbon black counter electrode.

The invention has successfully used the array type electrospinning technology to prepare the titanium dioxide anode fiber membrane, so that the efficiency is not much different from the doctor blade method. In addition, the present invention also successfully applies the array electrospinning process to the preparation of the counter electrode, and the efficiency is similar to that of the doctor blade method, which is very helpful for the large-area mass production process of the dye-sensitized solar cell.

The invention utilizes the array spinning technology in electrospinning to control the arrangement direction by using the electric field of the collecting substrate, and the degree of directionality is usually closely related to the conductivity, and the aligned fiber membranes should be easily conductive than the disorderly arranged fiber membranes. The application of electrons in one-dimensional materials should be more obvious. Therefore, the array type electrospinning technique of the present invention uses two equal-voltage negative electrodes, causing the fibers to be stretched due to the attraction of two electric fields of the same size, and the rules are laid flat. Between the two negative electrodes, so you only need to put the substrate of the fiber we want to coat on the negative electrode collection plate, so that the fibers can be arranged in parallel on the substrate. The principle is shown in Figure 1 (Dan Li and Yuliang Wang; WE Teo and S Ramakrishna), in which the syringe and the collecting plate are vertical, because the syringe is connected to the high voltage and has a positive charge, and the parallel collecting plate has a negative charge due to the connection of the negative electrode, which is caused by the attraction of the charge. The fibers are sprayed onto the collection plate. For example, two sheets of negative-voltage collecting plates can be used to arrange the fibers between the two collecting plates, so that the fibers are arranged more neatly, which makes the current transfer easier, and the tightness can be increased due to the neat arrangement. Improve the photoelectric conversion efficiency per unit area. Figure 2 (WE Teo at al.; Dan Li and Yuliang Wang) shows a scanning electron microscope (SEM) image of a titanium dioxide photoanode fiber membrane prepared by an ordinary electrostatic electrospinning technique and an array electrostatic electrospinning technique. The fiber membrane obtained by the array type electrostatic electrospinning technique has regularity, uniformity, and good tightness between the film and the film.

The invention uses the array type electrospinning technology to fabricate the electrode film to improve the photoelectric efficiency, and the prepared array film has regularity, uniformity, and good tightness between the film and the film, and can effectively shorten the electron path. Therefore, the efficiency of the dye-sensitized solar cell can be greatly improved, and it is suitable for a large-area mass production process, and the cost is also lower than the screen printing process.

In detail, according to a first embodiment of the present invention, the present invention provides a method for preparing a photoanode for a dye-sensitized solar cell, comprising the steps of: (1-1) preparing a titania colloid, the colloid comprising: a rice-type titanium dioxide; a polymer for assisting film formation; a solvent; and a dispersing agent to be added as needed; (1-2) electrospinning the titania colloid on a substrate by an array type electrospinning method, The substrate is placed on two equal-voltage collecting plates to form a titanium dioxide fiber film on the substrate; and (1-3) the titanium dioxide fiber film obtained in the sintering step (1-2) is used to obtain a titanium dioxide photoanode.

We have found that in recent years, many people have tried to prepare titanium dioxide precursors into electrospinning liquid to form a non-woven nano-titanium dioxide fiber membrane on the substrate, but the titanium dioxide precursor itself is easily hydrolyzed, and the control in electrospinning is not easy, and The titanium dioxide photoanode electrospun from the titanium dioxide precursor cannot be treated by hydrothermal treatment, so that the electrospun titanium dioxide does not reach the better crystallinity and particle size, so it can only be used as a large particle scattering layer of the titanium dioxide photoanode.

The invention directly utilizes the titanium dioxide nano-particles which have reached high efficiency conditions to form an electrospinning liquid, and prepares the titanium dioxide nanofiber membrane by the array electrospinning technology. The titanium dioxide type suitable for use in the present invention includes, but is not limited to, titanium dioxide nanotubes, titanium dioxide nanowires, titanium dioxide nanorods, titanium dioxide nanobelts, titanium dioxide broccoli structures, and titanium dioxide nanostructures.

The electrospun titanium dioxide precursor can only be sintered to form titanium dioxide nanoparticles of about 50 nm, but the physical properties of the titanium dioxide can be freely changed by the method of the invention, and the stretching force of the polymer in the electrospinning liquid is combined with electrospinning technology. The fibers are arranged and coated on the substrate in a non-woven form.

The preparation of the electrospinning liquid must have a matrix in which the polymer is stretched, and the titanium dioxide film is also required to add a polymer to enhance its film forming property during the production process, and the residual position at the sintering can form a hole. The pores contribute to the adsorption of the dye and the permeability of the electrolyte. Polyethylene Glycol (PEG) is a commonly used polymer for doctor blade coating.

According to the present invention, electrospinning requires a certain viscosity to be drawn into a fibrous form. Therefore, the titanium dioxide colloid of the present invention can be prepared, and a polymer which assists in film formation can be added, and polyethylene oxide (PEO) is preferably used.

The above manufacturing method may further comprise the steps of: preparing a dye solution, and then immersing the titanium dioxide photoanode by immersion, generally, soaking for more than 8 hours; or using an electric spray to make the dye solution TiO 2 Extremely colored, this step is to place the titanium dioxide film on the collector end, and then electrospray the dye solution onto the titanium dioxide film using an electrospinning device. EFI can be completed in about 1 hour using EFI, which saves a lot of time compared to the immersion method. In addition, since it takes at least 8 hours to soak the dye and the effect of re-use of the dye solution is not good, not only the production cost of the battery is increased, but also the discharge of the waste water is troubled. At most, electrospinning takes only one hour, which greatly shortens the production time and improves the efficiency of the overall process automation, and produces less dye residue, which is helpful for improving the quality stability of the dye-sensitized solar cell.

In detail, according to a second embodiment of the present invention, the present invention provides a method for preparing a platinum counter electrode for a dye-sensitized solar cell, comprising the steps of: (2-1) preparing a platinum-electrode electrospinning solution, The platinum counter electrode electrospinning liquid comprises chloroplatinic acid (H ₂ PtCl ₆ ‧6H ₂ O); a polymer for assisting film formation; a solvent; and a dispersing agent added as needed; (2-2) in an array Electrospinning electrospinning the platinum electroplating solution onto a substrate, wherein the substrate is placed on two equal voltage collecting plates to form a platinum counter electrode fiber film on the substrate; and (2- 3) The platinum counter electrode fiber film obtained in the sintering step (2-2) is obtained to obtain a platinum counter electrode.

When the platinum electroplating electrospinning liquid of the invention is prepared, carbon black may be doped to improve the tightness of the fiber membrane and the substrate, and the good electrical conductivity and high specific surface area of the carbon black are used to increase the contact area of the electrolyte, and at the same time It also reduces the amount of chloroplatinic acid used to reduce costs.

When the platinum electroplating electrospinning liquid of the present invention is prepared, a polymer which assists in film formation may be added, and polyoxyethylene is preferably used.

In view of the application to substrates and even textiles which are not resistant to high temperatures, a platinum counter electrode can be prepared by a low temperature preparation method. At present, the reducing agent NaBH ₄ is generally used to reduce platinum, and it is only required to be treated at 110-130 ° C, preferably 120 ° C.

Therefore, the present invention may optionally prepare a sodium borohydride (NaBH ₄ ) electrospinning solution (mainly composed of sodium borohydride and water) before performing the above steps (2-3), and then electrospinning by array electrospinning. The sodium borohydride electrospin is subjected to the step (2-3) on the platinum counter electrode fiber film obtained in the above step (2-2), followed by sintering at a temperature of 110 to 130 ° C for 11 to 13 hours.

In addition, the present invention may also prepare a sodium borohydride (NaBH ₄ ) electrospinning solution (the main component is sodium borohydride and water) and then sinter at a temperature of 110 to 130 ° C before performing step (2-3). Step (2-3) is carried out under conditions of 13 hours, and then the platinum counter electrode obtained in the step (2-3) is immersed in the sodium borohydride electrospin for 2 to 4 hours.

In detail, according to a third embodiment of the present invention, the present invention provides a method for preparing a carbon black counter electrode for a dye-sensitized solar cell, comprising the following steps: (3-1) preparing a carbon black counter electrode electrospinning Liquid, the carbon black counter electrode electrospinning liquid comprises carbon black; titanium dioxide precursor slurry; high molecular polymer for assisting film formation; solvent; and dispersing agent (3-2) added as needed Electrospinning the carbon black counter electrode electrospinning liquid onto a substrate, wherein the substrate is placed on two equal voltage collecting plates to form a carbon black counter electrode fiber membrane on the substrate; and (3-3 The carbon black counter electrode fiber film obtained in the sintering step (3-2) is subjected to a carbon black counter electrode.

The titanium dioxide precursor slurry used in the present invention contains isopropyl titanium oxide and acetic acid.

When the carbon black counter electrode electrowinning liquid of the present invention is prepared, a polymer which assists in film formation may be added, and polyoxyethylene is preferably used.

When preparing the titania colloid, the platinum counterelectrolytic solution and the carbon black counterelectrolyte of the present invention, the solvent used includes, but is not limited to, water, ethanol, isopropanol or the like or a combination thereof.

In order to make the electrospun fiber membrane very uniform, a dispersing agent may be added to the titania colloid, the platinum counterelectrolytic solution and the carbon black counter electrospinning liquid of the present invention as needed. Dispersing agents for use in the present invention include, but are not limited to, Acetylacetone (ACAC), polyoxyethylene octyl phenyl ether (Triton X-100), or combinations thereof.

The array type electrostatic electrospinning process voltage of the present invention can be 4 to 10 kV, and the syringe flow rate used in the electrospinning process is 0.5 to 1 mL/hr.

According to another embodiment of the present invention, the dyed anode and the counter electrode with the area defined by the insulating tape are sandwiched together in a sandwich structure, and the electrolyte is filled in the syringe to complete the dye-sensitized solar cell. Assembly.

The present invention may be embodied in a number of forms and manners, and the following description of the exemplary embodiments of the present invention is not intended to limit the invention, and may be readily modified and changed by anyone skilled in the art. It is the scope of the invention.

The implementation of the above related inventions will be illustrated by the following specific examples.

According to the current-voltage characteristic curve (IV curve) of the solar cell, its photoelectric characteristics, such as open-loop voltage (Voc), short-circuit current (Isc), fill factor (FF), and photoelectric conversion efficiency (η), can be known. .

The term "open-loop voltage (Voc)" as used herein refers to a solar cell that is in an infinite load (R is close to ∞), that is, when the external current is broken, the voltage is measured, and it is the maximum voltage that the photovoltaic cell can generate. . In general, the larger the open-loop voltage of a solar cell, the better.

The term "short current (Isc)" as used herein refers to the output current of a solar cell under no-load conditions (R = 0), that is, when the external circuit is short-circuited, which is the maximum photocurrent that the photocell can produce. In an ideal state, the short-circuit current of the solar cell is equal to the current generated when the light is illuminated. In general, the larger the short-circuit current of the solar cell, the better. By dividing the short-circuit current by the area, a short-circuit photocurrent density (Jsc) is obtained.

The term "filling factor (FF)" as used herein refers to the product of the operating characteristic density of any operating point in the IV characteristic curve under illumination, which is equal to the current density and voltage corresponding to the point. There is one operating point (Vmax). The output power density Pmax of Imax is the largest. The ratio of the maximum output power density to the Jsc, Voc product is defined as the fill factor FF. For a good solar cell, in addition to Jsc, Voc is higher, the fill factor should be closer to 1, the better, in fact, FF is less than 1. FF is a value without units.

The term "photoelectric conversion efficiency (η)" as used herein refers to a value that best exhibits the performance of a solar cell, and is defined as the ratio of the maximum output power (P _max ) of the solar cell to the incident light power (P _in ).

Preparation of titanium dioxide photoanode Example 1 1.1 Preparation of titanium dioxide photoanode by traditional process (scraper method)

Dilute 0.45 g of nano-sized titanium dioxide crystal powder into a mortar with a microbalance, add 0.025 mL of Triton X-100 and 0.05 mL of Acetylacetone (ACAC), and add 3 mL of pure water. Finally, 0.45 g of polyethylene glycol (PEG) was repeatedly milled until a gel-like uniform colloid was obtained. Then, the titanium substrate was cleaned in a shaking tank with deionized water and ethanol, and the 3M tape was cut. A hole of square area of 0.7*0.7 is placed, and then attached to a clean titanium substrate which has been dried after washing, and then a titanium dioxide colloid is added to the hole and uniformly coated by a doctor blade method. After natural drying, it is further heated to 450 ° C for 1 hour at a heating rate of 50 ° C / 30 minutes. After taking out, the area of titanium dioxide is scraped into 0.5 * 0.5 cm ^ 2 to complete the doctor blade titanium dioxide photoanode.

1.2 Preparation of titanium dioxide nanogel electrospinning solution

Use a microbalance to measure 1.5 g of nano-sized TiO2 crystal powder into a mortar, add 9 mL of ethanol, 3 mL of pure water and 1 mL of acetic acid, and finally add 0.15 g of PEO for 1 day until an approximation is obtained. A gel-like homogeneous gel can be used.

1.3 Ordinary electrospinning

Inject the nanogel electrospinning solution prepared in step 1.2 into the syringe. The flow rate of the syringe pump is adjusted to 0.5~1 mL/1h, the voltage is 4~10 kV, and the distance from the needle to the collecting plate is 5~10 cm. Place the clean substrate we want to coat on the collection plate, then soak the protective mold for 10 seconds. (The protective film is prepared by adding: 11.4 g of isopropyl titanium oxide to 100 mL of 8 M acetic acid, stirring for 1 day), and coating is completed. After that, the temperature was raised to 450 ° C for 2 hours at a heating rate of 50 ° C / 30 minutes. After taking out, the area of the titanium dioxide was scraped into 0.5 * 0.5 cm ^ 2 to complete the electrospinning titanium dioxide photoanode.

1.4 Array type electrospinning

Use the nanogel electrospinning solution prepared in step 1.2, the voltage used is 4~10 kV, the flow rate of the peristaltic pump is 0.4~1 mL/hr, and the distance between the collecting plate and the injection needle is 5~10 cm. Then soak the protective mold for 10 seconds (protective film is: 8M acetic acid 100 mL added 11.4 grams of isopropyl titanium oxide, stirred for 1 day), after spraying, at 50 ° C / 30 minutes heating rate, rose to 450 ° C sintering After 2 hours, after removing, the area of titanium dioxide was scraped into 0.5*0.5 cm 2 to complete the titanium dioxide photoanode prepared by array electrospinning.

Table 1 lists the results of the comparison of the photoelectric efficiency of the photoanodes prepared in the different preparations in Example 1. The current value of electrospinning is higher than the coating, but the FF value is low. The reason may be that the fiber is not in good contact with the substrate, resulting in too much dark current, and the efficiency of the array type is higher than that of the conventional one. Obviously, because of the high current value, this is in line with our prediction that regular alignment can lead to more electrons. Although the entire film can have good electron transfer characteristics, the tightness of the entire film and the substrate itself is insufficient, which is also a problem that scholars have encountered in recent years using electrospinning. However, with the increase of photocurrent, the efficiency can reach 100% of the blade coating type, which can be said to be the same. However, electrospinning has the advantages of large area, unrestricted raw material and anode shape, and mass production. Both commercialization and large-scale production have potential.

Table 1 Comparison of photoelectric efficiency between electrospinning methods

Preparation of counter electrode electrospinning solution and preparation of counter electrode by electrospinning Example 2 2.1 Preparation of platinum counter electrode

0.1 g of chloroplatinic acid was dissolved in 2 mL of isopropanol and 1 mL of water, 0.01 g of polymer PEO was added, stirred for 3 hours, coated on the substrate by electrospinning, and sintered at 450 ° C for 40 minutes to form a Pt counter electrode. Table 2 shows the comparison of the photoelectric efficiency of the platinum counter electrode obtained by the present invention and the platinum counter electrode obtained by the conventional coating process.

Table 2 Comparison of Photoelectric Efficiency Between Different Methods of Coating the Counter Electrode (Front Illumination)

* Prepare a titanium dioxide photoanode on a FTO glass substrate using the titanium dioxide slurry obtained in step 1.1 of Example 1, and apply a large particle titanium dioxide scattering layer thereon.

As shown in Table 2, the present invention utilizes a platinum fiber film made by electrospinning. In the case of front illumination, the photoelectric efficiency efficiency is similar to that of the platinum electrode made by the doctor blade method, and even we can find that the electrospinning is made. Platinum electrode efficiency is slightly higher than the scraping method. It is presumed that the electrospun white gold fiber contributes to the directional alignment, and the array electrospinning technology makes the electrospun membrane more compliant. The efficiency can be higher than the scraping method. In addition, we also tried to dope carbon black to improve the tightness with the substrate and use its good conductivity and high specific surface area to improve the contact of the electrolyte, while also reducing the amount of H ₂ PtCl ₆ used to reduce cost. In addition, comparing the two sets of arrayed H ₂ PtCl ₆ counter electrodes, the photocurrent of the array-type counter electrode of the doped carbon black is slightly increased, and the higher specific surface area makes the contact between the electrolyte and the cathode easier, so that the cathode is reduced. The effect of the electrolyte is better.

2.2 Preparation of carbon black counter electrode

Take 0.5 g of nano carbon black particles, add 0.15 g of PEO, 0.05 mL of Acetylacetone (ACAC) and 0.025 mL of Triton X-100 in 6 mL of water and 3 mL of ethanol, stir for 1 day, and finally add 1 mL of titanium dioxide precursor. The solution (preparation: 8 M acetic acid 100 mL was added to 11.4 g of isopropyl titanium oxide and stirred for 1 day) was electrosprayed onto the substrate, and sintered at 450 ° C for 1 hour to form a carbon black counter electrode. Table 3 shows the comparison of the photoelectric efficiency of the platinum counter electrode obtained by the present invention and the platinum counter electrode obtained by the conventional coating process.

Table 3 Comparison of Photoelectric Efficiency of Different Carbon Black Counters

**Preparation of titanium dioxide photoanode on FTO glass substrate using the titanium dioxide slurry obtained in step 1.1 of Example 1.

Carbon black is a commonly used counter electrode for dye-sensitized solar cells in recent years. The literature reports that the highest efficiency of cathode formed by carbon black nanoparticle has reached about 80% of platinum cathode, which is very helpful to reduce costs. As shown in Table 3, the present invention utilizes an array type electrospinning technique to prepare a carbon black fiber membrane as a counter electrode of a dye-sensitized solar cell, and the efficiency can be close to 80% of platinum. We found that the electrospun fiber membrane was very uniform due to the addition of the dispersant. In addition, the adhesive titanium dioxide precursor was used as the adhesive, but the titanium dioxide precursor was very easily hydrolyzed in water, so we used acetic acid to reduce the hydrolysis. The speed can also be mixed with our water-containing electrospinning liquid without too fast hydrolysis, and the titanium dioxide precursor will form an anatase crystal form after sintering at 450 ° C, and the carbon black and the substrate will be tightly grasped to make the film The change is tight and firm, and the efficiency is close to 80% of the traditional counter electrode. However, the low cost of carbon black nano particles deeply affects the future market competitiveness. With the advantage of large area of electrospinning, it is the most promising replacement. Cathode material for platinum.

The disclosure of the present invention is intended to explain how to make and use the various embodiments of the present invention, and not to limit the true, intended and appropriate scope of the invention and the spirit of the invention. The above discussion is not intended to be exhaustive or to limit the invention. In light of the above teachings, corrections or variations are possible. The embodiments may be selected and described in order to provide a description of the embodiments of the invention, All such amendments and variations are within the scope of the invention as defined by the scope of the appended claims and all equivalents thereof. These amendments and changes may be modified during the pending period.

references

1. W.E. Teo, M. Kotakil, X.M. Mol and S. Ramakrishna, Nanotechnology, 16 (2005) 918-924.

2. Mohamed B. Bazbouz, George K. Stylios, Journal of Applied Polymer Science, Vol. 107, 3023-3032 (2008).

3. W.E.Teo and S. Ramakrishna, Nanotechnology 16 (2005) 1878-1884.

4. Dan Li, Yuliang Wang, Nano Lett., Vol. 3, No. 8, 2003.

Figure 1 is a schematic view showing the formation of an array of electrospun fibers;

2 shows a scanning electron microscope (SEM) image of a titanium dioxide photoanode fiber membrane of (a) a general formula and (b) an array electrospinning method;

(no component symbol description)

Claims (13)

A method for preparing a photoanode for a dye-sensitized solar cell, comprising the steps of: (1-1) preparing a titania colloid comprising: a nano-sized titanium dioxide; a polymer for assisting film formation Solvent; and dispersing agent added as needed; (1-2) electrospinning the titania colloid on a substrate by array electrospinning, wherein the substrate is placed on two equal-voltage collecting plates, so as to facilitate A titanium dioxide fiber membrane is formed on the substrate; and (ii) a titanium dioxide fiber membrane obtained by the sintering step (1-2) is obtained to obtain a titanium oxide photoanode. The method of claim 1, wherein the nano-sized titanium dioxide is a titanium dioxide nanotube, a titanium dioxide nanowire, a titanium dioxide nanorod, a titanium dioxide nanobelt, a titanium dioxide broccoli structure or a titanium dioxide nanostructure. A method for preparing a platinum counter electrode for a dye-sensitized solar cell comprises the following steps: (2-1) preparing a platinum-electrode electrospinning liquid comprising chloroplatinic acid (H ₂ PtCl ₆ ‧ 6H ₂ O); a polymer for assisting film formation; a solvent; and a dispersing agent to be added as needed; (2-2) electrospinning the platinum electroplating solution on a substrate by an array type electrospinning method The substrate is placed on two equal-voltage collecting plates to form a platinum counter electrode fiber film on the substrate; and (2-3) the platinum counter electrode fiber film obtained by the sintering step (2-2) To get the platinum counter electrode. The method of claim 3, wherein in the step (2-1), carbon black is added to the platinum electroplating solution as needed. The method of claim 3, wherein before the step (2-3), the sodium borohydride (NaBH ₄ ) electrospinning solution is prepared, and the sodium borohydride electrospinning solution is electrospun in an array electrospinning step. (2-2) The obtained platinum is applied to the electrode fiber membrane, followed by sintering at a temperature of 110 to 130 ° C for 11 to 13 hours to carry out the step (2-3). The method of claim 3, wherein before the step (2-3), the sodium borohydride (NaBH ₄ ) electrospinning solution is prepared, and the step is performed by sintering at a temperature of 110 to 130 ° C for 11 to 13 hours (2). -3), the platinum counter electrode obtained in the step (2-3) is then immersed in the sodium borohydride electrospin for 2 to 4 hours. A method for preparing a carbon black counter electrode for a dye-sensitized solar cell, comprising the steps of: (3-1) preparing a carbon black counter electrode electrospinning liquid, the carbon black counter electrode electrospinning liquid comprising carbon black; and a titanium dioxide precursor a slurry; a polymer for assisting film formation; a solvent; and a dispersing agent (3-2) electrospinning the carbon black counter electrospinning liquid onto a substrate by an array electrospinning method, wherein the substrate is Placed on two equal-voltage collecting plates to form a carbon black counter electrode fiber film on the substrate; and (3-3) a carbon black counter electrode fiber film obtained by the sintering step (3-2) to obtain carbon Black counter electrode. The method of claim 7, wherein the titanium dioxide precursor slurry comprises isopropyl titanium oxide and acetic acid. The method of any one of claims 1 to 8, wherein the polymer is polyethylene oxide (PEO). The method of any one of claims 1 to 8, wherein the solvent is selected from the group consisting of water, ethanol, isopropanol, and mixtures thereof. The method of any one of claims 1 to 8, wherein the dispersing agent is selected from the group consisting of: Acetylacetone (ACAC), polyoxyethylene octyl phenyl ether (Triton X-100), and a group of mixtures thereof. The method of any one of claims 1 to 8, wherein the electrospinning process voltage is 4 to 10 kV. The method of any one of claims 1 to 8, wherein the syringe flow rate of the electrospinning process is from 0.5 to 1 mL/hr.