TW201205925A - Multilayer nanostructured titanium oxide photoelectrode and manufacturing method thereof - Google Patents

Abstract

A multilayer nanostructured titanium oxide photoelectrode and manufacturing method thereof are provided. In the manufacturing method, a first neutral aqueous phase titanium dioxide (TiO2) sol is prepared, and then the first neutral aqueous phase TiO2 sol is coated, dried and sintered on a substrate to form a dense layer. Thereafter, a second neutral aqueous phase TiO2 sol is prepared, and its particle size is controlled to be more than that of the first neutral aqueous phase TiO2 sol. Afterward, the second neutral aqueous phase TiO2 sol is coated, dried and sintered on the dense layer to form at least one buffer layer, and then a porous layer is then formed on the buffer layer. The first and second neutral aqueous phase TiO2 sols are utilized without adding any organic binding agent.

Description

201205925ji2TW 34830twf.doc/n VI. Description of the Invention: [Technical Field] The present invention relates to a titanium dioxide photoelectrode for a dye-sensitized solar cell (DSSC), and more particularly to a multilayer structure of nano titanium dioxide light Electrode and method of manufacturing the same. [Prior Art] A dye-sensitized solar cell is composed of a substrate, a transparent conductive film, a semiconductor photoelectrode, a dye, a charge transporting medium (electrolyte/solvent), and a counter electrode. Currently, the upper and lower substrates are often used as glass substrates. . In the conventional process of preparing the photoelectrode, the TiOj paste containing the organic binder is coated on the conductive (four) substrate, and then subjected to a high-temperature sintering process to make the 2 Ti02 particles have a good connection. And remove the slurry of organic dead binder. The traditional method is to use isopropyl (titanium isGpn) pQxide, ττιρ) 2 flooding 'water _ cheng Cheng Lai, in the titanium metal high pressure 加 warm water τκΓ理骚2 crystalline Ti〇2 particles, and then add The organic knotting agent is formed into 4 s =, and is applied to the substrate. 'High temperature calcination (about use. 'Forming a porous film, as a photoelectrode of a sensitized battery ^ Battery is a must-have for the battery. The heat-resistant temperature avoids the change and the 'slowing the sintering temperature may face some problems, such as the complete solution of the I method, the porosity of the film is reduced, and the adhesion between the film and the substrate is poor, and the TiO 2 particles are interposed. .......ii'W 34830twf.doc/n Poor knot, etc. These problems will directly affect the overall efficiency of the battery. In addition, the traditional Ti〇2 photoelectrode is fabricated directly on a transparent conductive substrate. Coating a porous Ti〇2 film, because of the relationship between the hole and the conductive substrate, the electrons flowing through the conductive substrate recombine with the electrolyte in the hole, resulting in the generation of dark current, resulting in the battery Reduced efficiency, especially on metal substrates such as stainless steel When the substrate is used, the influence of dark current is more obvious, which seriously reduces the photocurrent and conversion efficiency. In order to prevent the generation of dark current, recent studies have found that a dense layer must be deposited between the conductive substrate and the porous layer by using Ticl4. As a precursor, the conductive substrate is pretreated by immersion, and then subjected to high temperature calcination to form a dense layer. Some people use titanium organic compounds as precursors to form a sensitive layer on the substrate by Southern temperature spray cracking. For example, the U.S. patent is still 6,683,244. However, the compactness of the dense layer formed by such a method is obviously insufficient, so the dark current is limited to be reduced, and both are subjected to high temperature treatment (>450. 〇, cannot be used in a low temperature process, plus The precursor used is strongly acidic and cannot be used on a metal substrate, so it is greatly limited in application. In order to overcome the difficulty in fabricating a TiO2 photoelectrode at a low temperature, it is also studied to add an organic binder and pressurization (1) , 000 Kg/cm2 to 10,000 Kg/cm2) in a manner that promotes the bonding of the Ti02 nanopowder to the flexible substrate, as in US Pat. No. 7,224,036. Machine binder and Ti〇2 nano powder mixed component 'processed by pressure 20 MPa~200 MPa. The above method is to form a low temperature type Ti〇2 photoelectrode by applying extreme pressure, due to pressure Very high, can not be used for large area sun 201205925 -----v〇12TW 34830twf, doc / n battery production, and equipment costs, thus limiting the practicality of the method. [Summary of the Invention] The present invention provides a multilayer structure The manufacturing method of the nano titanium dioxide photoelectrode can reduce the dark current by adjusting the structure particle size, and improve the photocurrent and the battery efficiency. The present invention further provides a multilayer structure nano titanium dioxide photoelectrode, which can reduce dark current and improve photocurrent and cell efficiency. The invention provides a method for manufacturing a multilayer structure nano titanium dioxide photoelectrode, which comprises preparing a first neutral aqueous titanium dioxide sol, coating, drying and calcining the first neutral aqueous titanium dioxide sol on a substrate, Forming a sensitive layer. Weaving, preparing - the second neutral aqueous phase is dihydrated and is controlled to reduce the reduction of the second aqueous phase of the titanium dioxide by more than the above-mentioned fraction of the aqueous titanium dioxide sol. Next, the second aqueous phase titanium dioxide sol is coated, dried and calcined on the sensitive layer to form at least. Formed on the porous layer, where in the first. - No organic drilling agent is added to the neutral aqueous phase titania sol. The method for preparing the above-mentioned first and second neutral water titanium oxide sols comprises the steps of synthesizing the W layer by a procedure of titanium metal salt solution, precipitation, water washing, degumming and heating and refluxing. The particle size of the porous::! aqueous phase dioxygen sol is larger than the particle size of the second middle third titanium sol, and is coated and dried on the buffer layer ^ 201205925 34830twf.doc/ n Synthesized with procedures for reading, washing, degumming and warming reflux. In the actual wipe of the present invention, the above-mentioned first, second and third neutrals are prepared in accordance with the conditions for the preparation of the titanium oxide, except for the above-mentioned heating time. The longer the heating is called, the longer the second, the second and the third neutral aqueous titanium dioxide sol. In one embodiment of the present invention, the heating and refluxing time is within 5〇=time. The prepared first, second and third neutral aqueous phase titanium dioxide/gluten has a particle size ranging from 1 nm to 300 nm. In one embodiment of the present invention, the first neutral aqueous phase titanium dioxide = the particle size of the gel is from 1 nm to 8 nm. The temperature of the first neutral aqueous titanium dioxide sol is heated, for example, from 0.5 hour to 1 Torr. hour. In one embodiment of the invention, the second neutral aqueous titanium dioxide sol has a particle size of from 8 nm to 20 nm. The warming reflux time for preparing the second neutral aqueous titanium dioxide sol is, for example, 10 hours to 20 hours. In an embodiment of the invention, the third neutral aqueous titanium dioxide sol has a particle size of from 20 nm to 300 nm. The warming reflux time for preparing the third neutral aqueous titanium dioxide sol is, for example, 20 hours to 50 hours. 201205925 12TW 34830twf.doc/n In one embodiment of the invention, the substrate comprises a conductive glass or a metal material. In one embodiment of the present invention, before the first neutral aqueous titanium dioxide sol is coated on the substrate, the substrate is subjected to hydrophilic treatment using atmospheric plasma to enhance the aqueous phase sol coating effect. In one embodiment of the present invention, the first neutral aqueous titanium dioxide sol is coated on the substrate, and the second neutral aqueous titanium dioxide sol is coated on the dense layer, including a immersion plating method or a spraying method. It is preferably a dip-plating method. In an embodiment of the present invention, the method of forming a porous layer on the buffer layer may be first preparing a titanium dioxide paste, adding an organic binder to the titanium dioxide slurry, and then coating the buffer layer. The above titanium dioxide slurry is clothed, dried and calcined. The present invention further provides a multilayer structure nano titanium dioxide photoelectrode for use in a dye-sensitized solar cell comprising at least one uniform layer, a porous layer and at least one buffer layer. The sensitive layer, the porous layer and the buffer layer are composed of a plurality of titanium dioxide particles. The buffer layer is located between the dense layer and the porous layer to promote particle bonding between the dense layer and the porous layer to enhance photocurrent generation, wherein the particle size of the porous layer is larger than the particle size of the enamel layer, and at least one buffer layer The particle size ranges between the particle size of the dense layer and the particle size of the porous layer. In still another embodiment of the present invention, the film thickness of the dense layer is 50 nm to 500 nm, the film thickness of the at least one buffer layer is 〇 1 μm to ι μηη, and the film thickness of the porous layer is 2 μm to 30 μm. 7 201205925: iW 34830twf.doc/n In another embodiment of the present invention, the ratio of the particle diameter of the porous layer to the particle diameter of the at least-buffer layer is 3 to 1 〇, and the at least one retarded particle diameter The ratio of the particle diameter to the dense layer is 3 to 1 Torr. In still another embodiment of the present invention, the density of the above-mentioned sensitive layer is 1% to 30%, and the effect of suppressing dark current can be 1 〇 5 A/cm 2 or less at 〇 7 volts. In another embodiment of the present invention, the porous layer has a pore size of 5 nm to 30 Å and a surface area of 50 m 2 /g to 15 〇 m 2 /g, and the porosity is

Based on the above, the present invention uses a neutral aqueous phase Ti 〇 2 sol as a starting material, and regulates the particle size of the sol, and is made by coating according to the difference of the granules. Bribe layer, buffer layer or porous layer. The sensitive layer produced is sensitive: the effect is very high. The effect of suppressing dark current is more obvious, and the series is not corrosive, so it can be directly applied to the coating of metal substrates. The same coating method can also be used for the production of the buffer layer and the porous layer film. Since the neutral aqueous phase Ti〇2 sol used in the present invention does not need to be added with an organic binder, it can be used in a low temperature process.

The above described features and advantages of the present invention will become more apparent from the description of the appended claims. [Embodiment] Fig. 1 is a cross-sectional view showing a dye-sensitized solar cell according to an embodiment of the present invention. Referring to FIG. 1, the dye-sensitized solar cell of the embodiment 1〇〇8 2012〇5925ui2tw 34830twf.doc/n includes a multilayer structure nano titanium dioxide photoelectrode 102 including at least a uniform dense layer 104 and at least one buffer layer 106. With a porous layer 1〇8. The dense layer 1 〇 4, the buffer layer 106 and the porous layer 1 〇 8 are each composed of a plurality of titanium dioxide particles. The dense layer 104 is used to prevent the electrolytic solution 110 of the dye-sensitized solar cell from directly contacting the conductive substrate 112 to suppress the occurrence of dark current. The porous layer 108 provides a surface area as a carrier for adsorbing the dye 114 to promote light absorption and photoelectron generation. In the present embodiment, the film thickness of the dense layer is, for example, 50 nm to 500 nm, and the film thickness of the porous layer 1〇8 is, for example, 2 μm. ~30μιη. Further, the porosity of the above-mentioned sensitive layer 1〇4 is, for example, ι / 〇 30 ° /. The effect of suppressing dark current is, for example, i 〇 -5 A/cm 2 or less at 〇 7 volts. The porous layer 108 has a pore size of, for example, 5 nm to 3 Å, a surface area of, for example, 50 m 2 /g to 150 m 2 /g, and a porosity of, for example, 30% to 65 Å / Torr. In FIG. 1, the buffer layer 106 is located between the dense layer 1〇4 and the porous layer 1〇8 to promote particle bonding between the dense layer 1〇4 and the porous layer 1〇8, and to enhance photocurrent generation, wherein porous The particle diameter of the layer 1〇8 is larger than the particle diameter of the dense layer 1〇4, and the particle diameter of the at least one buffer layer 1〇6 is between the particle diameter of the dense layer 1〇4 φ and the particle diameter of the porous layer 108, Therefore, the bondability between the dense layer 1〇4 and the porous layer 108 can be improved. For example, the ratio of the particle size of the porous layer 8 to the particle size of the buffer layer 106 is, for example, 3 to 1 Å, and the ratio of the particle diameter of the buffer layer 106 to the particle diameter of the dense layer 104 is, for example, 3 to 10 . The film thickness of the buffer layer 106 is, for example, 〇.ipm 〜1 μιη. As for the other members of the dye-sensitized solar cell 100, the prior art can be cited. For example, the counter electrode 118 formed on the surface of the counter substrate 116 is opposed to the multilayered nano titanium dioxide photoelectrode 丨02. 1 w 34830twf.doc/n 201205925 A multilayered structure of a nanometer example. Referring to Fig. 2, a titanium oxide sol is prepared in the step of the step. The preparation of the first neutral aqueous phase 2 described above, for example, by the method of riding a lighter type (such as tetrachloroethylene), the longer the time is, the longer the solution is, the more the solution is, the more The first neutral description of heating back to ί ΐ ΐ 在 在 在 在 在 在 在 在 在 在 制备 制备 制备 制备 制备 制备 制备 制备 制备 制备 制备 制备 制备 制备 制备 制备 制备 制备 制备 制备 制备 制备 制备 制备 制备 制备 制备 制备 制备 制备 制备 制备 制备 制备Nm~8 nm; for example, preparing such a first neutral aqueous phase-titanium oxide to be heated and refluxed at about W hours to feed. In step 202, coating, drying and coating on the substrate The first neutral aqueous titanium dioxide sol is calcined to form a dense layer. It is not necessary to add an organic drilling agent to the first neutral aqueous titanium dioxide sol during the step. The above coating method is, for example, immersion plating or spraying. The coating method is preferably a immersion plating method, and the calcined first-neutral aqueous phase titanium oxide sol has a temperature of about 2 〇〇r to 550 C, and the temperature is lower than 450. (: Preferably, the calcination method includes heating. Body heating method (such as using a chrome wire heating body heating furnace) or infrared heating method, in which red at low temperature Preferably, the temperature of the first neutral aqueous phase titanium oxide sol is 1 Torr. (: 〜15 (TC. The above substrate is, for example, a conductive glass or a metal material. Further, before step 202, the atmosphere may be used first) The plasma is hydrophilically treated to enhance the aqueous phase sol coating effect. 201205925 ------J12 Γ W 3483 Oiwf. d〇c/n Then 'in step 204, the fee borrows a wall, sol, And need to control the second neutral aqueous phase neutral water phase dioxidation to describe the first-neutral aqueous phase dioxide dioxide: ==== program and synthesis. Note: = two = = oxygen = sol (four) The vehicle can be smashed, except for the time of heating the zone. Because the temperature = the longer the flow time, the second neutral aqueous phase of the prepared titanium dioxide has a large grain reading. For example, when the temperature is reflowed (4) In the 50 hours, the particle size range of the titanium dioxide sol of the first aqueous phase is 1 2~3_n ^ In this real customs, the grain size of the second neutral aqueous phase dioxide cold gel is 8nm~ 2Gnm; for example, the preparation of such a second water-phase titanium dioxide sol is heated at a reflux time of about 1 hour. Thereafter, in step 206 The second neutral aqueous titanium dioxide sol is coated, dried and calcined on the dense layer to form at least one buffer layer. 11 'W 3483〇twf.doc/n 201205925 If necessary, the heavy frost can be pushed Forming - above layer, f on step 2 () 4 to 206, to ==: step to enhance the aforementioned _= shape: see stepped porous layer, its detailed step is savory. 4 steps 212 to 216, J: step Stone 210 is more suitable for low temperature process. Firstly, in step (10), the third neutral aqueous phase bath gel is prepared, and the third neutrality is controlled, and the second-aqueous phase is the second: :;:!:: genus: class (such as four gasification recorded) program synthesis, degumming and heating reflux to attack the first, second and third neutral aqueous phase titanium dioxide 2 >, the preparation conditions are When the same time, the temperature of the heating and reflux can be changed to make the bath pellet control. For example, the longer the temperature is refluxed, the larger the particle size of the prepared third = aqueous titanium dioxide sol. For example, the temperature of the third neutral aqueous phase of titanium dioxide dissolved within 5G hours is between 1 nm and 3 〇〇 nm. In the present embodiment, the particle size of the third effluent phase-titanium oxide sol is from 2 〇 nm to 300 nm; for example, the temperature of the third neutral aqueous titanium dioxide sol is prepared to be refluxed for about 20 hours. 5 hours. Then, in step 21, coating, drying and calcining the second neutral aqueous titanium dioxide sol on the buffer layer to form a porous layer, wherein no organic bonding is added in the third neutral aqueous titanium dioxide sol Agent. The above-mentioned coating method 12 201205925 34830 twf.doc/n is, for example, a dip or tilting method, preferably a spraying method. The temperature of the calcined third neutral aqueous titanium dioxide sol is about 2〇〇t~55〇t, and the temperature is lower than 45 (TC is preferred. The calcined third neutral aqueous titanium dioxide sol includes the hair Heating method or infrared heating method, at a low temperature, the temperature of the titanium dioxide sol is about 100 ° c 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 2^(paste), the slurry referred to herein may be prepared by the prior art, and is not described here. Then, in step 214, an organic binder is added to the Ti 2 2 compound, wherein the organic binder is, for example, Hydroxyethyl cellulose (ethyiceuul〇se), etc., then 'in step 216, coating, drying and calcining the above titanium dioxide slurry on the buffer layer to form a porous The slurry used in steps 212 to 216 has a sintering temperature of 4 55 (TC) because it contains a contact agent.

Several experiments are listed below to verify the effects of the present invention. Experiment 1 First, the preparation of the above neutral aqueous titanium oxide sol was observed, and the relationship between the time of warming reflux and the prepared dissolved _ was observed. In the experiment, four titanium hydride (TiCl4) was used as the precursor. First, 54 fertilizer 4 was dissolved in 23.2 ml of deionized water. The dissolution method was to slowly drop the deionized water towel to titrate _ about 15 minutes. Weaving, the diluted 1M TiCl4 (28.6 ml) and 3G% NH4OH solution (about 2 〇ml) were used to neutralize the sinking chamber by slowly dropping the NH4〇H solution into the TiCl4 solution 20120592^34, titrating the end point. For pH = 8, the time required is approximately 90 minutes. After the end of the titration, the mixture was aged for 2 hours. The sediments must be washed and filtered for a total of five repetitions, using a water pump (aspirator) or mechanical pump for suction filtration. The filtered cake was added with an appropriate amount of deionized water and stirred for 2 hours. Hydrogen peroxide (35%, 27 ml) was slowly added (about 5 minutes), and stirring was continued for about 30 minutes to complete the degumming. After the solution is warmed up to 90 °C, the temperature is refluxed, and the temperature is refluxed from 0.5 hours to 4 hours, and about 200 mL of aqueous phase can be synthesized.

Dioxide sol. The obtained sol was neutral, pH was 7 to 8.5, and the appearance was pale yellow and clear. Dynamic Light Scattering (Dalamic Light Scattering, Malvern)

Zetasizer Nano) analyzes particle size. The particle size becomes larger as the reflow time increases. The dependence is shown in Fig. 3. The reflux time is G5 hours, and the sol having a particle size of K2 nm can be obtained. When the reflux time is increased to 4 hours, a sol having a diameter of 100 rnn or more can be obtained.

The pores obtained by drying and calcining the sols of different particle sizes after coating are as follows: _ and · degrees (constantly different, the relationship between grain size and porosity is shown in Table 1. Surface surface

201205925

Ji2TW 34830twf.doc/n 36.2 7.8 70.5 39 51.3 9.5 107.8 53 63 7.5 85.4 41 108 12.8 81.5 54 As shown in Table 1, when the particle size is increased from 3.6 nm to 51.3 nm, the hole size is increased from 4.8 nm to 9.5 nm. The surface area increased from 58.8 m2/g to 107.8 m2/g, and the porosity ij increased from 28% to 53%. When the particle size continues to increase from 51.3 nm to 108 nm, the pore size increases to 12.8 nm, the specific surface area decreases to 81.5 m2/g, and the porosity is approximately the same as 54%. In the second experiment, the neutral aqueous phase titanium dioxide sol was calcined at a low temperature (2 Torr., and a good pore size, specific surface area and porosity were obtained. The sol with a particle size of 108 nm in Table 1 of Experiment 1 For example, at low temperature (200. 〇 and high temperature (450. The comparison of the hole characteristics obtained by underarm calcination is shown in Table 2. Table 2)

The resulting hole _, shouting _ is large

^ can still be m / g) 'porosity is slightly increased (56%), showing that under low temperature forging can still (four) j good Lai hole characteristics. Experiment 3 15 2012〇5?25tw 3483〇twfd〇c/n For the production of the dense layer, the difference between the neutral aqueous titanium dioxide sol and the conventional technique was observed. Using a neutral aqueous phase titanium dioxide sol having a particle size of about 1 nm to 8 nm prepared in Experiment 1, the MFT0 glass substrate was coated by immersion plating, and the substrate was subjected to hydrophilic treatment using atmospheric plasma before the coating. To increase the adhesion of the sol. 3 '. The coating is dried at 120 °C and then calcined in a high-temperature furnace. The calcination temperature is 45 °C. The thickness of the sensitive layer can be controlled by the number of coatings. Under the two coating times, the thickness of the dense layer is expanded. The round meter measures about 1 〇〇 nm. A dense layer made of a neutral aqueous phase titanium dioxide sol having a particle size of 1.5 nm (the porosity of sample-1 is about 20%, and the dense layer made of a neutral aqueous titanium dioxide sol having a particle size of 5 nm (sample 2) The porosity is about 3〇0/〇. As for the conventional dense layer, there are two kinds of methods: (1) The surface of 4FT glass with 4 isopropyl alcohol (TTIP) is coated by spin coating. A layer of TTIP solution (3 〇μ1 of TTIP was added! 〇mi in ethanol), the sample was placed in an oven for drying, and then calcined at 45 ( (Comparative Example 1). (2) Four gasification Titanium (Ticl4) was used as a starting material: FT 〇 glass was immersed in a 40 mM TiCl4 aqueous solution for 30 minutes (7 〇. 〇. 鈇德檨), after washing with ethanol and deionized water, the sample was placed in ^ Drying in the box (120 C)' is then calcined at 45 °C (Comparative Example 2). The dark micro evaluation is carried out after the mouth. The evaluation method is (4) the dense layer (sample 1, sample 2, comparison) Example 1 and Comparative Example 2) As electrodes, the components were analyzed for dark current and compared with the ft-glass ratio of the uncoated dense layer. The presence of a dense layer can significantly reduce the generation of dark current, and the smaller the particle size of Ti〇2 used in making the 201205925_ 34830twf.doc/n dense layer, the effect of suppressing dark current is obvious. Figure 4 is made of different particle sizes. The effect of the dense layer on the dark current of the Ti〇2 photoelectrode. As can be seen from Fig. 4, the dark current can be reduced by a dense layer (sample 1) made of a neutral water phase titanium oxide sol having a particle diameter of 15 nm. To 1〇_5 A/cm2 or less (when the voltage is 0.7 V); when the particle size is increased to 5 nm (sample 2), the dark current is slightly higher than 5xl〇·5 A/cm2 (the voltage is 〇·7 乂) At the same time, both of them are lower than the dark current of the FTO glass (> 丨〇-4 A/em2 @ 〇7 VV) which is not coated with a dense layer, and is also denser than that produced by a conventional method (Comparative Example 1) And Comparative Example 2) The obtained dark current is low, and the effect of suppressing dark current generation by the dense layer made of the neutral aqueous phase cerium oxide sol of the present invention is sufficiently exhibited. Experiment 4 compares the single-layer photoelectrode with the multilayer structure of the present invention. The difference in photoelectric characteristics of nano titanium dioxide photoelectrode. The preparation of buffer layer is the use of experiment one. A neutral aqueous phase titanium oxide sol with a particle size of about 8 nm to 2 〇 φ nm was coated on the dense layer of 1.5 nm diameter prepared by Experiment 3 by dipping. The bond film was dried at 120 C. After calcination in a high-temperature furnace, the calcination temperature is 45 ° C. The thickness of the buffer layer can be controlled by the number of coatings. Under the application times of twice, the thickness of the buffer layer is about 15 〇 nm. A neutral aqueous phase titanium oxide sol having a particle diameter of about 20 nm to 150 nm prepared in Experiment 1 was applied to the above buffer layer by spray coating. The coating is dried by 120 and then calcined in a high temperature furnace, 17 34830twf.doc/n 201205925

The .TW calcination temperature was 450 °C to complete the fabrication of a multilayered nano titanium dioxide photoelectrode. As for the single-layer photoelectrode, the above porous layer is formed directly on the surface of the FTO glass to have a thickness of about 8 μm. The photoelectrode of a single-layer or multi-layered titanium dioxide film is first adsorbed with an appropriate amount of dye (Ν719, (Bu4N)4[Ru(dcbpy)2(NCS)2]), plus electrolyte (I2/LiI/3-曱) Oxypropionitrile) and the counter electrode form a battery element. Then use the solar simulator as a light source to illuminate the battery components with an illumination intensity of 1,000 W/m2 (1 sun)' and measure the photocurrent generated at different voltages using a voltage/current generator to create a voltage-current characteristic curve. To calculate the photoelectric conversion efficiency of the battery. The photoelectric property measurement results are shown in Table 3. Table 3 Sample category Jsc mA/cm2 V〇〇mV FF V % Single layer photoelectrode 7.9 750 0.59 3.5 Multilayer structure Nano titanium dioxide photoelectrode 9.9 740 0.54 3.9 Multilayer structure Nano titanium dioxide photoelectrode for higher photocurrent and conversion Efficiency, in which the photocurrent was increased from 7.9 mA/cm2 to 9.9 mA/cm2, and the conversion efficiency was increased from 3.5% to 3.9%. In the fifth experiment, the dense layer and the buffer layer were prepared in the same manner as in the experiment 4. The preparation of the porous layer was carried out by using a conventional Ti〇2 compound as a starting material, and coated by spin coating method 201205? 2512Tw 34830twf.doc/n. On the buffer layer, after drying at 120 ° C and then calcining through a high temperature furnace, the forging temperature is 450 ° C to form a multilayer structure nano titanium dioxide photoelectrode. When a porous layer film is directly coated on the surface of the FTO glass, a photoelectrode of a single layer structure is formed. The thickness of the porous layer film is about 10 μm. A photoelectrode coated with a single-layer or multi-layer Ti〇2 film was formed into a battery element in the same manner as in Experiment 4, and a solar light simulator was used as a light source to illuminate the battery element 'light intensity is 1, 〇〇〇W/m2 (l sun), the voltage/current generator is used to measure the photocurrent generated at different voltages, and a voltage-current characteristic curve is generated to calculate the photoelectric conversion efficiency of the battery. The results of photoelectric characteristics measurement are shown in Table 4. Table 4 sample categories] sc mA/cm2 V〇c mV FF V % single-layer photoelectrode 6.8 739 0.64 3.2 multi-layer structure nano-dioxide optical electrode 13.8 758 0.68 7.1 • multi-layer structure nano titanium dioxide photoelectrode can get higher Photocurrent and conversion efficiency 'where the photocurrent increased from 6.8 mA/cm2 to 13.8 mA/cm2, the conversion efficiency increased from 3.2% to 7.1%. Experiment 6 The fabrication of a multilayered nano-titanium dioxide photoelectrode and a single-layer photoelectrode was carried out in the same experiment. However, a stainless steel (SS304) substrate was used instead of the FTO glass substrate, and the thickness of the porous layer was about 8 μm. The photoelectric characteristics measurement results are shown in Table 5. 34830twf.doc/n 201205925 . Table 5 Sample Category Jsc mA/cm2 V〇c mV FF V % Single Layer Photoelectrode 3.0 683 0.67 1.4 Multilayer Structure Nano Dioxide Photoelectrode 9.1 687 0.56 3.5

The multilayer structure of the nano titanium dioxide photoelectrode can obtain higher photocurrent and conversion efficiency, in which the photocurrent increases from 3.0 mA/cm2 to 9.1 mA/cm2, and the conversion efficiency increases from 1.4% to 3.5%. The experimental seven-layer structure nano titanium dioxide photoelectrode was fabricated in the same manner as in Experiment 4, but the calcination temperature was changed to 200 °C, and the heating method was calcined by an infrared heater to form a photoelectrode and constitute a dye-sensitized solar cell element. Test its photoelectric properties. The photoelectric property measurement results are shown in Table 6. Table 6 Calcination temperature,. c Jsc mA/cm2 V v oc mV FF V % 200 4.6 769 0.68 2.4

, w g gΊ-ψ to the photoelectric conversion efficiency of 2.4%, confirmed the use of neutral aqueous titanium dioxide sol as a starting material' can effectively produce photoelectrodes at low temperatures and applied to dyes' solar cells. The photoelectrode produced by the conventional Ti〇2 slurry under the conditions of calcination at 200 °C cannot effectively perform photoelectric conversion. Although the present invention has been disclosed in the above embodiments, it is not intended to limit the scope of the present invention, which is not limited to the scope of the present invention, without departing from the spirit and scope of the present invention. A few modifications and refinements may be made, and the scope of protection of the present invention is defined by the scope of the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a cross-sectional view of a dye-sensitized solar cell in accordance with an embodiment of the present invention. Fig. 2 is a view showing the steps of fabricating a multilayer structure nano titanium dioxide photoelectrode according to another embodiment of the present invention. Figure 3 is a graph showing the relationship between the particle size of Experiment 1 and the reflux time. Figure 4疋 The relationship between the dense layer and the darkness of different particle sizes in Experiment 2 [Explanation of main components] 100: Dye-sensitized solar cell 102·Multilayer structure Nano-dioxide light electrode 104: dense layer 106: slow Punching layer 108: porous layer 110: electrolyte 112: substrate 114: dye 116: opposite substrate 118: counter electrode 200 to 216: step 21

Claims (1)

uW 34830twf.doc/n 201205925 Seven patent application scope: 1. A method for manufacturing a multi-layered nano-titanium dioxide photoelectrode, package preparation-first-neutral aqueous titanium dioxide sol; coating, drying and forging on a substrate Burning the titanium sol to form a dense layer; τ water phase oxidizing the neutral aqueous phase titanium dioxide sol, and (4) the second medium café has a larger particle size than the first neutral water phase oxidized: Drying and calcining the second neutral aqueous phase dioxygenate to form at least one buffer layer; and forming a porous layer on the at least one buffer layer, and drilling the first and the third: Aqueous phase: Oxygen _ Jing does not add organic qingguang 2 electricity ▲ Scope range mentioned in item 1 ◎ layer structure nano dioxin ==: method, in which the preparation of the first - and second neutral water t neutral, The metal salt _ precursor is synthesized by dissolving, neutralizing, washing, degumming and heating reflux. The multi-layered gentleman 槿太丰备== method according to the first aspect of the patent application, in the at least slow rubber and controlling the third neutral neutral phase titanium dioxide preparation - the third neutral aqueous phase titanium dioxide aqueous solution phase The particle size of the oxidized sol is greater than the particle size of the sol; and 22 201205925 0 ------i) l2TW 34830twf.d〇c/n ^ coating, drying and calcining the at least one buffer layer A third intermediate phase-titanium oxide sol in which no tantalum crucible is added to the third neutral aqueous phase. 4. In the secret glue 4. If the application paste _3 excerpt == method, the method for preparing the third neutral At 〜 includes: using a titanium metal salt as a precursor, dissolved precipitation, water washing, degumming and heating Synthesized by reflowing the program. 5. If the second or fourth application of the patent application scope is the same as the manufacturing method of the titanium dioxide photoelectrode, the preparation condition of the second water removal phase-titanium oxide is removed, except for the time of heating and refluxing. The multilayer structure described in the fifth aspect of the invention is characterized in that the longer the time for the warming and refluxing is, the larger the titanium dioxide is prepared for the first, second and third flake aqueous phases. 7. The method for producing a multilayer structure nano titanium dioxide photoelectrode according to claim 6, wherein the heating, refluxing time is within 50 hours, and the first, second and third neutral waters are prepared. The phase of the oxidized sol has a particle size ranging from lmn to 300 nm. 8. The method of producing a multilayer structure nano titanium dioxide photoelectrode according to claim 7, wherein the first neutral aqueous titanium dioxide sol. has a particle size of from 1 nm to 8 nm. The method for producing a multilayer structure nano titanium dioxide photoelectrode according to claim 8, wherein the warming reflux time of the first neutral aqueous titanium dioxide sol is prepared. In 〇 5 hours to 1 hour. 10. The method for producing a multilayer structure nano titanium dioxide photoelectrode according to claim 7, wherein the second neutral aqueous phase titanium dioxide sol has a particle size of 8 nm to 20 nm. The method for producing a multilayer structure nano titanium dioxide photoelectrode according to claim 10, wherein the heating and refluxing time of the second neutral aqueous titanium dioxide sol is from 1 to 2 hours. 12. The method for producing a multilayer structure nano titanium dioxide photoelectrode according to claim 7, wherein the third neutral aqueous phase titanium dioxide sol has a particle size of 20 nm to 30 〇 nm. 13. The method for producing a multilayer structure nano titanium dioxide photoelectrode according to claim 12, wherein the heating and refluxing time of preparing the third neutral aqueous titanium dioxide sol is from 2 to 5 hours. . H. The method of producing a multilayer structure nano titanium dioxide photoelectrode according to claim 2, wherein the substrate comprises a conductive glass or a metal material. 15. The method for producing a multilayer structure nano titanium dioxide photoelectrode according to the above-mentioned claim, wherein before the coating the first neutral aqueous titanium dioxide sol on the substrate, the method further comprises: using atmospheric plasma to The substrate is subjected to a hydrophilic treatment. 16. The method for producing a multilayer structure nano titanium dioxide photoelectrode according to claim 1, wherein the first neutral 24 201205925 J12TW 34830twf.doc/n aqueous titanium dioxide sol is coated on the substrate and The method of coating the second neutral aqueous titanium dioxide sol on the dense layer includes a immersion plating method or a spraying method. 17. The method for producing a multilayer structure nano titanium dioxide photoelectrode according to claim 1, wherein the method for forming the porous layer on the at least one buffer layer comprises: preparing a titanium dioxide slurry; An organic binder is added to the slurry; and the titanium dioxide slurry is coated, dried and calcined on the at least one buffer layer. 18. The nano layer structure nano-mono-oxidation electrode is used for a dye-sensitized solar cell. The multilayer structure nano titanium dioxide photoelectrode comprises at least: a sensitive layer composed of a plurality of titanium dioxide particles; a porous layer composed of a plurality of titanium dioxide particles; and at least one buffer layer between the dense layer and the porous layer, composed of a plurality of titanium dioxide particles to promote particle bonding between the dense layer and the porous layer, Wherein the particle size of the porous layer is larger than the particle size of the dense layer, and the particle size of the at least one buffer layer ranges between the particle size of the dense layer and the grain size of the porous layer. 19. The multilayer structure nano titanium dioxide photoelectrode of claim 18, wherein the dense layer has a film thickness of 50 nm to 500 nm, a film thickness of the at least one buffer layer, and a film thickness of the porous layer. The multilayered nano titanium dioxide photoelectrode of the above-mentioned claim, wherein the particle size of the porous layer and the particle of the at least one buffer layer are 25 201205925 x'W 34830twf.doc/n The ratio of the diameters is 3 to 10, and the ratio of the particle diameter of the at least one layer to the particle diameter of the dense layer is 3 to 10. 21. The nano titanium dioxide photoelectrode of claim 18, wherein the dense layer has a porosity of 1% to 30%, and the effect of suppressing dark current can reach 1 (T5A/cm2) at 〇7 volts. 22. The nano titanium dioxide photoelectric 2 according to claim 18, wherein the porous layer has a pore size of 5 nm to 30 nm, a surface area of m / g 15 15 m 2 / g, and a porosity of 3 %. ~65〇/〇. 26