Dye-sensitized solar cell and preparation method thereof

Abstract

The present invention provides a dye-sensitized solar cell and a preparation method thereof, the preparation method comprising: step S1, washing a substrate, and preparing a ZnO photoanode and a platinum seed film through the substrate respectively; step S2, placing the platinum seed film in a mixed solution consisting of a chiral small molecule solution, a chloroplatinic acid solution, and an ascorbic acid solution, heating at a set temperature for a certain time, and preparing a chiral platinum counter electrode; step S3, pre-treating the ZnO photoanode, laminating the pre-treated ZnO photoanode with the chiral platinum counter electrode, and infiltrating an electrolyte into the laminating surface formed by the ZnO photoanode and the chiral platinum counter electrode, and preparing a dye-sensitized solar cell. The dye-sensitized solar cell prepared by the preparation method improves the absorption efficiency of polarized light, thereby improving the efficiency of photoelectric conversion of the dye-sensitized solar cell.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to a dye-sensitized solar cell and a preparation method thereof. Background Art

[0002] Solar energy is a renewable energy source, which refers to the thermal radiation energy of the sun, and its main manifestation is what people often call sunlight. Solar energy is generated by the huge nuclear energy released by hydrogen-helium fusion of hydrogen atoms inside the sun, and it is the radiation energy from the sun. Therefore, the use of solar energy is safe, reliable, clean and pollution-free, thus reducing pollution to the environment. At present, the utilization of solar energy is mainly in three main forms: photothermal conversion, photoelectric conversion and photochemical conversion, that is, converting solar energy into thermal energy, electrical energy and chemical energy. Solar cells are an application of photoelectric conversion and use photoelectric semiconductor wafers that directly generate electricity from sunlight, also known as "solar chips".

[0003] Dye-sensitized solar cells are a new type of solar cell that mainly imitates the principle of photosynthesis. They use low-cost nano-titanium dioxide and photosensitizing dyes as the main raw materials to simulate the photosynthesis of plants in nature using solar energy to convert solar energy into electrical energy. Compared with traditional silicon solar cells, dye-sensitized solar cells have the advantages of long life (service life can reach 15 to 20 years), low production cost (only one-fifth to one-tenth of silicon solar cells, and the cost of each peak watt of the battery is expected to be less than 10 yuan), and non-toxic and pollution-free production process. The efficiency of photoelectric conversion of dye-sensitized solar cells depends largely on their absorption efficiency of sunlight. Natural light will form partial polarized light after being reflected by an object. Traditional dye-sensitized solar cells often only consider the absorption efficiency of natural light, but ignore the absorption efficiency of polarized light. Therefore, how to further improve the absorption efficiency of polarized light is a difficult problem that dye-sensitized solar cells urgently need to solve.

[0004] In view of this, it is necessary to improve the dye-sensitized solar cells in the prior art to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to solve the problem of low photoelectric conversion efficiency of dye-sensitized solar cells in the prior art, which is caused by the fact that the dye-sensitized solar cells only consider the absorption efficiency of natural light, but do not consider the absorption efficiency of polarized light formed after natural light is reflected by an object.

[0006] To achieve the above object, the present invention provides a method for preparing a dye-sensitized solar cell, comprising:

[0007] Step S1, washing the substrate, and preparing a ZnO photoanode and a platinum seed film through the substrate respectively;

[0008] Step S2, placing the platinum seed film in a mixed solution consisting of a chiral small molecule solution, a chloroplatinic acid solution and an ascorbic acid solution, heating at a set temperature for a certain time to prepare a chiral platinum counter electrode;

[0009] Step S3, pretreating the ZnO photoanode, bonding the pretreated ZnO photoanode to the chiral platinum counter electrode, and infiltrating the electrolyte into the bonding surface formed by the ZnO photoanode and the chiral platinum counter electrode to prepare a dye-sensitized solar cell.

[0010] As a further improvement of the present invention, the molar ratio of the chiral small molecule, chloroplatinic acid and ascorbic acid in step S2 is 1-3.5:2-4:45-50.

[0011] As a further improvement of the present invention, the chiral small molecule solution is a chiral cysteine ​​solution.

[0012] As a further improvement of the present invention, the step S1 of preparing the ZnO photoanode by the substrate includes: uniformly scraping the ZnO slurry on the surface of the substrate, and heating the substrate coated with the ZnO slurry at a set temperature for a certain period of time.

[0013] As a further improvement of the present invention, the step S1 of preparing the platinum seed film by the substrate includes: spreading a 15 mM isopropanol solution of chloroplatinic acid on the surface of the substrate, and heating the substrate coated with the isopropanol solution of chloroplatinic acid at a set temperature for a certain period of time.

[0014] As a further improvement of the present invention, the substrate coated with the ZnO slurry is placed in a muffle furnace and heated to 350-500° C. and calcined for 6-12 hours.

[0015] As a further improvement of the present invention, the substrate coated with 15 mM chloroplatinic acid isopropanol solution is heated in an oven at 80° C. for 15 min, taken out and placed in a muffle furnace and heated to 400-500° C. for calcination for 30 min.

[0016] As a further improvement of the present invention, the pretreatment of the ZnO photoanode in step S3 includes:

[0017] The ZnO photoanode is cut into a preset size and placed in a N719 dye sensitizer at 50-70° C. for 24 hours to prepare a pretreated ZnO photoanode.

[0018] As a further improvement of the present invention, after the electrolyte is infiltrated into the bonding surface formed by the ZnO photoanode and the chiral platinum counter electrode in step S3, the method further includes: packaging the dye-sensitized solar cell by epoxy resin glue.

[0019] Based on the same inventive concept, the present invention also discloses a dye-sensitized solar cell.

[0020] The dye-sensitized solar cell is prepared based on the preparation method of the dye-sensitized solar cell described in any one of the above inventions.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The chiral platinum in the chiral platinum counter electrode in the dye-sensitized solar cell has optical activity and can selectively reflect polarized light in a specific direction, thereby improving the reflection efficiency of the chiral platinum counter electrode to polarized light, thereby improving the reflection efficiency of the dye-sensitized solar cell to polarized light, and ultimately ensuring the efficiency of photoelectric conversion of the dye-sensitized solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A flow chart of a method for preparing a dye-sensitized solar cell shown in the present invention;

[0024] Figure 2 for Figure 1 The specific flow chart of step S1 shown;

[0025] Figure 3 is a low-magnification SEM image of a chiral platinum counter electrode;

[0026] Figure 4 This is a high-magnification SEM image of a chiral platinum counter electrode;

[0027] Figure 5 is the circular dichroism (CD) spectrum of the chiral platinum counter electrode;

[0028] Figure 6 The JV curves of the dye-sensitized solar cells shown in Example 1 and the comparative example. DETAILED DESCRIPTION

[0029] The present invention is described in detail below in conjunction with the various embodiments shown in the accompanying drawings, but it should be noted that these embodiments are not limitations of the present invention, and any equivalent transformations or substitutions in functions, methods, or structures made by ordinary technicians in the field based on these embodiments are all within the scope of protection of the present invention.

[0030] Before elaborating on the various embodiments of the present application in detail, the applicant briefly describes the meanings of the unit abbreviations involved in the present application.

[0031] Unit "min": time unit, minute;

[0032] Unit "h": time unit, hour;

[0033] Unit "cm": unit of length, centimeter;

[0034] Unit "℃": temperature measurement unit, Celsius;

[0035] Unit "mM": concentration unit, mmol / L, millimole per liter;

[0036] Unit "g": unit of mass, gram;

[0037] Unit "mA / cm 2 ”: density unit, milliampere per square centimeter;

[0038] Unit "V": voltage unit, volt.

[0039] Please refer to Figure 1 As shown, Figure 1 A flowchart of a method for preparing a dye-sensitized solar cell is provided in one embodiment of the present application. The method at least includes steps S1 to S3.

[0040] Step S1, washing the substrate, and preparing a ZnO photoanode and a platinum seed film through the substrate respectively.

[0041] For example, Figure 2 As shown, step S1 specifically includes the following steps S11 to S13.

[0042] Step S11 , selecting a substrate, and washing the substrate with a mixed solution of anhydrous ethanol (analytical grade) and distilled water.

[0043] Specifically, a substrate is selected, and the substrate is washed with a mixed solution of ethanol and water. The substrate can be selected from FTO conductive glass (fluorine-doped tin dioxide conductive glass) or ITO conductive glass (conductive glass with sputtered indium tin oxide film). The substrate can be washed by ultrasonic washing or chemical washing. Ultrasonic cleaning refers to the use of ultrasonic cavitation, acceleration and straight flow in liquid to directly and indirectly act on liquid and dirt, so that the dirt layer is dispersed, emulsified and peeled off to achieve the purpose of cleaning. Chemical washing refers to the use of concentrated alkaline chemical reagents (alkaline ethanol washing solution) to remove oil, grease and dirt particles on the surface of the substrate.

[0044] Step S12, preparing a ZnO photoanode by evenly scraping the ZnO slurry on the surface of the substrate, and heating the substrate coated with the ZnO slurry at a set temperature for a certain time.

[0045] Specifically, ZnO slurry is prepared by solid phase grinding at room temperature, the ZnO slurry is formed into a film on the surface of a substrate by a doctor blade method, and then the substrate coated with the ZnO slurry is placed in a muffle furnace and heated at 350-500° C. for 6-12 hours to prepare a ZnO photoanode.

[0046] It should be noted that the room temperature solid phase grinding method refers to a solid phase reaction at room temperature, combining the principle of mechanical alloying with the theory of solid phase chemical reaction, and using the strong interlocking grinding effect of mechanical force to improve the contact between solid particles and improve the reaction efficiency. The scraping method refers to a method of thick film coating of a viscous coating using a metal or non-metal scraper. In addition, after forming the ZnO slurry by the room temperature solid phase grinding method, deionized water with a mass ratio of 1:0.2 to the ZnO slurry is added to the ZnO slurry and stirred evenly to form a ZnO slurry with the best viscosity, so that the ZnO slurry with the best viscosity is formed into a film on the surface of the substrate by scraping.

[0047] Step S13, preparing a platinum seed film by spreading a 15 mM isopropanol solution of chloroplatinic acid on the surface of the substrate, and heating the substrate coated with the 15 mM isopropanol solution of chloroplatinic acid at a set temperature for a certain period of time.

[0048] Specifically, a platinum seed film is prepared by preparing a 15 mM isopropanol solution of chloroplatinic acid and dripping it on the surface of the substrate. In the 15 mM isopropanol solution of chloroplatinic acid, chloroplatinic acid is used as a solute and isopropanol is used as a solvent to prepare a 15 mM isopropanol solution of chloroplatinic acid. The substrate dripped with the 15 mM isopropanol solution of chloroplatinic acid is placed in an oven at 80°C for 15 minutes, taken out and then placed in a muffle furnace and heated at 400-500°C for 30 minutes to obtain a platinum seed film with a bright surface.

[0049] Step S2, placing the platinum seed film in a mixed solution consisting of a chiral small molecule solution, a chloroplatinic acid solution and an ascorbic acid solution, heating at a set temperature for a certain time, and preparing a chiral platinum counter electrode.

[0050] Specifically, a mixed solution consisting of 1-3.5 mM chiral small molecule solution, 2-4 mM chloroplatinic acid solution and 45-50 mM ascorbic acid solution is prepared, and the molar ratio of chiral small molecule, chloroplatinic acid and ascorbic acid is 1-3.5:2-4:45-50. The platinum seed film prepared in the above step S13 is placed in the mixed solution (i.e., the mixed solution consisting of the above chiral small molecule solution, chloroplatinic acid solution and ascorbic acid solution), and placed in a constant temperature water bath at 50°C and heated for 20 minutes to prepare a chiral platinum counter electrode film. The chiral platinum counter electrode film is taken out and washed with a mixed solution of anhydrous ethanol (analytical grade) and distilled water in a volume ratio of 1:1, thereby preparing a chiral platinum counter electrode.

[0051] It should be noted that the chiral small molecule solution can act as a chiral inducer. Through the interaction between the chiral inducer and the platinum atoms, the platinum grains can be induced to arrange asymmetrically during the formation of platinum crystals to form platinum crystals with chiral structures. Ascorbic acid solution is used as a reducing agent to react with chloroplatinic acid solution. The hydroxyl groups of ascorbic acid provide electrons and are oxidized to dehydroascorbic acid, which can convert Pt 4+ Reduced to Pt. In addition, the chiral small molecule solution can be a chiral cysteine ​​solution.

[0052] Step S3, pretreating the ZnO photoanode, laminating the pretreated ZnO photoanode with a chiral platinum counter electrode, and infiltrating an electrolyte into the laminating surface formed by the ZnO photoanode and the chiral platinum counter electrode to prepare a dye-sensitized solar cell.

[0053] Specifically, the ZnO photoanode prepared in the above step S12 is cut into an area of ​​a specific size (for example, 1*1cm) and placed in the N719 dye sensitizer, and heated at 50-70°C for 24h to allow the ZnO photoanode to be fully impregnated with the N719 dye sensitizer. The ZnO photoanode fully impregnated with the N719 dye sensitizer is bonded to the chiral platinum counter electrode prepared in the above step S2, and a liquid electrolyte is dripped into the bonding point between the two. The electrolyte is infiltrated into the bonding surface formed by the ZnO photoanode and the chiral platinum counter electrode by capillary action to prepare a dye-sensitized solar cell. Finally, the dye-sensitized solar cell is encapsulated by epoxy resin glue to prevent the leakage of the electrolyte, and finally a complete dye-sensitized solar cell is obtained.

[0054] It should be noted that capillary action refers to the attraction of the liquid surface to the solid surface. For example, when a capillary is inserted into a wetting liquid, the liquid level inside the tube rises and is higher than the liquid level outside the tube; when the capillary is not immersed in a wetting liquid, the liquid level inside the tube drops and is lower than the liquid level outside the tube. This phenomenon is called capillary action. The role of the ZnO photoanode is to act as a carrier to adsorb the N719 dye sensitizer, which will generate photoelectrons after absorbing sunlight. The photoelectrons will be transmitted to the substrate through the ZnO photoanode and flow to the chiral platinum counter electrode through the external circuit to form an external current. The role of the chiral platinum counter electrode is to collect electrons transmitted from the external circuit and catalyze the redox reaction in the electrolyte to form an internal current. The chiral platinum counter electrode will also reflect light that is not fully absorbed by the ZnO photoanode back to the ZnO photoanode to improve the absorption efficiency of the dye-sensitized solar cell for sunlight. The chiral platinum counter electrode in the present invention has optical activity and can selectively reflect polarized light in a specific direction, especially has a better selective reflection effect on circularly polarized light, so as to improve the reflection efficiency of the chiral platinum counter electrode to polarized light, thereby improving the reflection efficiency of the dye-sensitized solar cell to polarized light, so as to ultimately ensure the efficiency of photoelectric conversion of the dye-sensitized solar cell.

[0055] After natural light is reflected or refracted by an object, most of the reflected light and refracted light are partially polarized light, and partially polarized light includes circularly polarized light. The dye-sensitized solar cell in the present invention has a chiral structure. The chiral structure has optical activity such as circular dichroism, and can only transmit or absorb circularly polarized light in one direction (left circularly polarized light / right circularly polarized light), and the circularly polarized light in the other direction will be completely reflected. The circularly polarized light reflected back to the ZnO photoanode will be reabsorbed by the N719 dye photosensitizer and generate photoelectrons, thereby greatly improving the absorption efficiency of the dye-sensitized solar cell for polarized light and thus improving the photoelectric conversion efficiency of the dye-sensitized solar cell.

[0056] In order to more clearly understand the method for preparing a dye-sensitized solar cell provided by the present application, a specific example is shown below to illustrate the method for preparing a dye-sensitized solar cell provided by the present application.

[0057] It should be noted that the FTO conductive glass substrate disclosed in the embodiment is - / I3 - The liquid electrolyte was prepared by Yingkou Aopivite New Energy Technology Co., Ltd. The remaining solutions were selected from commercial products or standard chemical reagents prepared by Sinopharm Chemical Reagent Co., Ltd.

[0058] Embodiment 1:

[0059] A method for preparing a dye-sensitized solar cell, the method comprising the following steps:

[0060] First, the FTO conductive glass substrate was cut into a size of 1.5*6cm, and ultrasonically washed in ethanol and distilled water for 10 minutes respectively before use. 0.4g of sodium hydroxide solid particles and 5.59g of Zn(NO3)2·6H2O solid particles were weighed and put into an agate mortar and pestle, and the agate pestle was used to grind the solid particles into liquid slurry to obtain ZnO slurry. The ZnO slurry was collected in a centrifuge tube and washed three times by centrifugation with water and ethanol.

[0061] Secondly, polyimide tape was pasted on both sides of the cleaned FTO conductive glass, leaving an area of ​​0.1 cm width in the middle of the FTO conductive glass. ZnO slurry was evenly coated on the 0.1 cm middle area. The coating thickness can be controlled by the number of tape layers pasted. After coating, the polyimide tape was torn off, and the FTO conductive glass coated with ZnO slurry was placed in a muffle furnace and calcined at 350 ° C for 6 hours to prepare a ZnO photoanode film. The ZnO photoanode film was cut into 1*1 cm square blocks with a scalpel to prepare a ZnO photoanode. The ZnO photoanode was placed in a dark box containing N719 dye photosensitizer, and the dark box was placed in an oven and heated at 50 ° C for 24 hours. After the N719 dye photosensitizer and the ZnO photoanode are fully impregnated, it was taken out, rinsed with anhydrous ethanol, and dried for use.

[0062] Then, chloroplatinic acid is dissolved in isopropanol to prepare a 15mM isopropanol solution of chloroplatinic acid. The 15mM isopropanol solution of chloroplatinic acid is horizontally dripped onto the FTO conductive glass by a drop coating method. The substrate with the 15mM isopropanol solution of chloroplatinic acid is placed in an oven and added at 80°C for 15min to fully volatilize the isopropanol, then taken out and placed in a muffle furnace and calcined at 450°C for 30min to prepare a platinum seed film with a bright surface. 0.005g (2mM) of L-configuration cysteine ​​and 0.041g (4mM) of chloroplatinic acid are dissolved in 20mL of ultrapure water, a platinum seed film is placed, and 2mL of 50mM ascorbic acid solution is added. Finally, the mixed solution consisting of the cysteine ​​solution, the chloroplatinic acid solution, and the ascorbic acid solution and the platinum seed film placed in the mixed solution were all placed in a constant temperature water bath at 50°C and heated at a constant temperature for 20 minutes to prepare a chiral platinum counter electrode film. The chiral platinum counter electrode film was taken out and washed with ethanol and the mixed solution to prepare a chiral platinum counter electrode.

[0063] Finally, place the spare ZnO photoanode and the chiral platinum counter electrode together, use a dropper to draw a small drop of liquid electrolyte, and drip about 0.1 ml of I2O along the joint between the two. - / I3 - Liquid electrolyte. The electrolyte is infiltrated into the bonding surface formed by the ZnO photoanode and the chiral platinum counter electrode through capillary action to prepare a dye-sensitized solar cell. Finally, the dye-sensitized solar cell is encapsulated with epoxy resin glue to prevent the electrolyte from leaking out and ensure the overall insulation of the dye-sensitized solar cell, and finally a complete dye-sensitized solar cell is obtained.

[0064] Comparison example:

[0065] First, the FTO conductive glass substrate was cut into a size of 1.5*6cm, and ultrasonically washed in ethanol and distilled water for 10 minutes respectively before use. 0.4g of sodium hydroxide solid particles and 5.59g of Zn(NO3)2·6H2O solid particles were weighed and put into an agate mortar and pestle, and the agate pestle was used to grind the solid particles into liquid slurry to obtain ZnO slurry. The ZnO slurry was collected in a centrifuge tube and washed three times by centrifugation with water and ethanol.

[0066] Secondly, polyimide tape was pasted on both sides of the cleaned FTO conductive glass, leaving an area of ​​0.1 cm width in the middle of the FTO conductive glass. ZnO slurry was evenly coated on the 0.1 cm middle area. The coating thickness can be controlled by the number of tape layers pasted. After coating, the polyimide tape was torn off, and the FTO conductive glass coated with ZnO slurry was placed in a muffle furnace and calcined at 350 ° C for 6 hours to prepare a ZnO photoanode film. The ZnO photoanode film was cut into 1*1 cm square blocks with a scalpel to prepare a ZnO photoanode. The ZnO photoanode was placed in a dark box containing N719 dye photosensitizer, and the dark box was placed in an oven and heated at 50 ° C for 24 hours. After the N719 dye photosensitizer and the ZnO photoanode are fully impregnated, it was taken out, rinsed with anhydrous ethanol, and dried for use.

[0067] Then, chloroplatinic acid is dissolved in isopropanol to prepare a 15mM isopropanol solution of chloroplatinic acid. The 15mM isopropanol solution of chloroplatinic acid is horizontally dripped onto the FTO conductive glass by a drip coating method. The substrate dripped with the 15mM isopropanol solution of chloroplatinic acid is placed in an oven at 80°C for 15 minutes to fully volatilize the isopropanol, then taken out and placed in a muffle furnace and calcined at 450°C for 30 minutes to prepare a platinum seed film with a bright surface. The aforementioned platinum seed film is an ordinary platinum counter electrode and does not have a chiral structure.

[0068] Finally, the spare ZnO photoanode and the platinum counter electrode are bonded together, a small drop of liquid electrolyte is sucked with a dropper, and the liquid electrolyte is dripped along the bonding point between the two. The electrolyte is infiltrated into the bonding surface formed by the ZnO photoanode and the platinum counter electrode through capillary action to prepare a dye-sensitized solar cell. Finally, the dye-sensitized solar cell is encapsulated with epoxy resin glue to prevent the electrolyte from leaking, and finally a complete dye-sensitized solar cell is obtained.

[0069] It should be noted that Figure 3 and Figure 4 As shown in Figure 1, chiral platinum is an asymmetric polyhedral particle structure. The width of the chiral platinum particles is 60-150nm and the length is 150-300nm. The particles are tightly stacked asymmetrically, presenting a long-range ordered chiral structure. Figure 5Shown is the circular dichroism (CD) spectrum of the chiral platinum counter electrode disclosed in the present invention. After testing, the chiral platinum counter electrode has CD values ​​in the entire near-ultraviolet light region (200-380nm) and the visible light region (380-780nm), proving that the chiral platinum counter electrode is optically active and exhibits the strongest optical activity at a wavelength of 356nm.

[0070] Ginseng Figure 6 The JV curves of the dye-sensitized solar cells prepared in Example 1 and the control example of the present invention are shown. When a chiral platinum counter electrode is used in Example 1, the short-circuit current density Jsc is 10.13 mA / cm 2 , the open circuit voltage Voc is 0.68V, the fill factor FF is 0.71, and the corresponding photoelectric conversion efficiency is 4.88%. When ordinary platinum counter electrode is used in the control example, the short circuit current density Jsc is 9.37mA / cm 2 , the open circuit voltage Voc is 0.68V, the fill factor FF is 0.67, and the corresponding photoelectric conversion efficiency is 4.24%. Figure 6 As shown, the integral area formed by the ordinary platinum electrode pair corresponding to the dotted line in the prior art relative to the horizontal coordinate and the vertical coordinate is significantly smaller than the integral area formed by the chiral platinum electrode pair prepared in Example 1 relative to the horizontal coordinate and the vertical coordinate. It can be seen that compared with ordinary platinum counter electrodes, the dye-sensitized solar cell assembled using chiral platinum counter electrodes in the present application has a higher open circuit voltage and short circuit current, and can obtain a higher photoelectric conversion efficiency. At the same time, since the chiral platinum counter electrode as a chiral substance is optically active, it can selectively pass and reflect circularly polarized light. After the circularly polarized light that is not fully absorbed by the ZnO photoanode reaches the chiral platinum counter electrode, the circularly polarized light in one direction will be completely reflected and reflected back to the ZnO photoanode until it is completely absorbed and utilized by the ZnO photoanode, thereby increasing the absorption efficiency of the circularly polarized light.

[0071] It can be seen that the dye-sensitized solar cell disclosed in the present invention can enhance the absorption efficiency of polarized light, and can especially improve the absorption efficiency of circularly polarized light (left circularly polarized light / right circularly polarized light), thereby generating more photoelectrons, due to the addition of an optically active chiral platinum counter electrode. Compared with dye-sensitized solar cells with ordinary platinum counter electrodes, it has a higher short-circuit current and fill factor. The open-circuit voltage of dye-sensitized solar cells is generally related to the Fermi level of the materials of its photoanode and counter electrode, but has nothing to do with the structure of the material. Therefore, compared with dye-sensitized solar cells with ordinary platinum counter electrodes, the open-circuit voltage of dye-sensitized solar cells with chiral platinum counter electrodes has not changed significantly. In general, the preparation method of the dye-sensitized solar cell provided by the present invention can increase the absorption efficiency of polarized light, thereby leading to an increase in short-circuit current and fill factor, and significantly improve the photoelectric conversion efficiency, providing a new path for the optimization and performance improvement of dye-sensitized solar cells.

[0072] At the same time, the cost of dye-sensitized solar cells is about 6 yuan per peak watt, where peak watt is the unit of calculation of solar device capacity; while the cost of silicon solar cells is about 50 yuan per peak watt. Therefore, the manufacturing cost of the dye-sensitized solar cell disclosed in the present application can be controlled at one-fifth to one-tenth of that of silicon solar cells, so the cost of dye-sensitized solar cells is lower than that of silicon solar cells. In the dye-sensitized solar cell prepared by the method for preparing a dye-sensitized solar cell shown in the present invention, the chiral platinum in the chiral platinum counter electrode can selectively reflect polarized light in a specific direction due to its optical activity, so as to improve the reflection efficiency of the chiral platinum counter electrode to polarized light, thereby improving the reflection efficiency of the dye-sensitized solar cell to polarized light, so as to ultimately ensure the efficiency of photoelectric conversion of the dye-sensitized solar cell, so that the dye-sensitized solar cell has a good commercial prospect.

[0073] The present invention also discloses a dye-sensitized solar cell, which is prepared based on the above-mentioned method for preparing a dye-sensitized solar cell. Since the dye-sensitized solar cell has a chiral structure. The chiral structure has optical activity such as circular dichroism, and can only transmit or absorb circularly polarized light in one direction (left circularly polarized light / right circularly polarized light), and the circularly polarized light in the other direction will be completely reflected, and the circularly polarized light reflected back to the ZnO photoanode will be reabsorbed by the N719 dye photosensitizer and generate photoelectrons, thereby greatly improving the absorption efficiency of the dye-sensitized solar cell for polarized light, and then improving the photoelectric conversion efficiency of the dye-sensitized solar cell. For its preparation method, refer to the detailed description above, which will not be repeated here. The description of the preparation method disclosed in the above embodiment is relatively specific and detailed, but it cannot be understood as a limitation on the scope of the patent application.

[0074] The series of detailed descriptions listed above are only specific descriptions of feasible implementation methods of the present invention. They are not intended to limit the scope of protection of the present invention. Any equivalent implementation methods or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

[0075] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0076] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for preparing a dye-sensitized solar cell, characterized in that: include: Step S1, washing the substrate, and preparing a ZnO photoanode and a platinum seed film through the substrate respectively; Step S2, placing the platinum seed film in a mixed solution consisting of a chiral small molecule solution, a chloroplatinic acid solution and an ascorbic acid solution, heating at a set temperature for a certain time to prepare a chiral platinum counter electrode; Step S3, pre-treating the ZnO photoanode, laminating the pre-treated ZnO photoanode with the chiral platinum counter electrode, and infiltrating an electrolyte into the laminating surface formed by the ZnO photoanode and the chiral platinum counter electrode, to prepare a dye-sensitized solar cell; Wherein, in step S2, the molar ratio of the chiral small molecule, chloroplatinic acid and ascorbic acid is 1-3.5:2-4:45-50, and heating is performed at 50° C. for 20 min.

2. The method for preparing a dye-sensitized solar cell according to claim 1, characterized in that: The chiral small molecule solution is a chiral cysteine ​​solution.

3. The method for preparing a dye-sensitized solar cell according to claim 1, characterized in that: The step S1 of preparing the ZnO photoanode by the substrate includes: uniformly scraping the ZnO slurry onto the surface of the substrate, and heating the substrate coated with the ZnO slurry at a set temperature for a certain period of time.

4. The method for preparing a dye-sensitized solar cell according to claim 1, characterized in that: The step S1 of preparing a platinum seed film by the substrate includes: spreading a 15 mM isopropanol solution of chloroplatinic acid on the surface of the substrate, and heating the substrate coated with the isopropanol solution of chloroplatinic acid at a set temperature for a certain period of time.

5. The method for preparing a dye-sensitized solar cell according to claim 3, characterized in that: The substrate coated with the ZnO slurry is placed in a muffle furnace and heated to 350-500° C. and calcined for 6-12 hours.

6. The method for preparing a dye-sensitized solar cell according to claim 4, characterized in that: The substrate coated with 15 mM chloroplatinic acid isopropanol solution was heated in an oven at 80° C. for 15 min, taken out and placed in a muffle furnace at 400-500° C. for calcination for 30 min.

7. The method for preparing a dye-sensitized solar cell according to claim 1, characterized in that: The pretreatment of the ZnO photoanode in step S3 includes: The ZnO photoanode is cut into a preset size and placed in a N719 dye sensitizer at 50-70° C. for 24 hours to prepare a pretreated ZnO photoanode.

8. The method for preparing a dye-sensitized solar cell according to claim 1, characterized in that: After the electrolyte is infiltrated into the bonding surface formed by the ZnO photoanode and the chiral platinum counter electrode in step S3, the method further includes: packaging the dye-sensitized solar cell by epoxy resin glue.

9. A dye-sensitized solar cell, characterized in that: The dye-sensitized solar cell is prepared based on the preparation method of a dye-sensitized solar cell according to any one of claims 1 to 8.

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