Method for carrying out structured processing on functional layer of perovskite solar cell

Abstract

The invention relates to a method for carrying out structured treatment on a functional layer of a perovskite solar cell, which comprises the following steps of: mixing magnetic particle materials with different magnetization intensities or piezoelectric particle materials with different piezoelectric coefficients with preparation materials of the functional layer of the perovskite solar cell; and coating the mixed solution on the surface of a substrate of a to-be-prepared functional layer to obtain a liquid film. And then applying a magnetic field or an electric field in a specific direction to the coated liquid film, so that the magnetic particle material or the piezoelectric particle material is arranged according to a specific route or pattern. And then annealing to cure the liquid film, and eluting the magnetic particle material or the piezoelectric particle material in the functional layer. And finally, drying the eluted functional layer so as to finish the structuring treatment of the functional layer. The method is simple and easy to implement, and the spectrum utilization rate of the perovskite solar cell is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of perovskite solar cell preparation, and in particular relates to a method for structuring a functional layer of a perovskite solar cell. Background Art

[0002] The energy conversion efficiency of perovskite solar cells is comparable to that of crystalline silicon solar cells, and is gradually approaching its theoretical efficiency limit. It is more challenging to further improve the conversion efficiency of perovskite solar cells. By regulating the band gap of perovskite light-absorbing materials and improving the utilization of the solar spectrum, the conversion efficiency can be improved. This method mostly uses solution synthesis. The solution method is easily affected by environmental factors and has low repeatability. In addition, by regulating the composition of each functional layer in the perovskite solar cell structure to make the energy levels of each functional layer more matched, or by reducing the surface defects of each layer, reducing the probability of carrier recombination, and introducing interface modification materials, the conversion efficiency can also be improved. However, the method of regulating the composition of each layer or introducing interface modification materials has high cost and long R&D cycle, which is not conducive to the development of commercial mass production of solar cells. Therefore, how to find a simple and efficient method to improve the spectral utilization of perovskite solar cells is crucial to improving the conversion efficiency. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a method for structurally processing the functional layer of a perovskite solar cell, which is simple and easy to implement, so as to improve the spectral utilization rate of the perovskite solar cell.

[0004] The present invention is implemented by providing a method for structuring a functional layer of a perovskite solar cell, comprising the following steps: Magnetic granular materials with different magnetization strengths or piezoelectric (ferroelectric) granular materials with different piezoelectric coefficients are mixed with the materials for preparing the functional layer of the perovskite solar cell to obtain a mixed solution, and then the mixed solution is coated on the surface of the substrate to be prepared for the functional layer to obtain a liquid film. Then a magnetic field or electric field in a specific direction is applied to the coated liquid film to arrange the magnetic granular material or piezoelectric granular material in a specific route or pattern. Then annealing is performed to solidify the liquid film, and then the magnetic granular material or piezoelectric granular material in the functional layer is eluted. Finally, the eluted functional layer is dried to obtain a functional layer after structured processing; wherein the functional layer is at least one of an electrode layer, a carrier transport layer and a perovskite light absorption layer, wherein the carrier transport layer includes a hole transport layer and an electron transport layer.

[0005] Compared with the prior art, the method of the present invention for structuring the functional layer of a perovskite solar cell is to mix magnetic granular materials with different magnetization strengths or piezoelectric (ferroelectric) granular materials with different piezoelectric coefficients with the preparation materials of the functional layer of the perovskite solar cell, and then apply the mixed solution on the surface of the substrate to be prepared for the functional layer to obtain a liquid film, and then apply a magnetic field or electric field in a specific direction to the coated liquid film to arrange the magnetic granular material or piezoelectric granular material according to a specific route or pattern, anneal the liquid film to solidify it, and then wash away the magnetic granular material or piezoelectric granular material in the functional layer to obtain a structured functional layer. The method of the present invention can obtain a perovskite solar cell with a complex light-harvesting structure and high energy conversion efficiency. Compared with the commonly used nanoimprinting method, this method has the advantages of precision, non-destructiveness, and mass production, and the magnetic materials and piezoelectric materials used can be recycled, reducing the manufacturing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 It is a schematic diagram of the state after coating the liquid film on the surface of the substrate in the method for structurally treating the functional layer of the perovskite solar cell of the present invention; Figure 2 for Figure 1 A schematic diagram of a method in which a magnetic field or electric field in a specific direction is applied to the coated liquid film to aggregate and arrange the magnetic particle material or the piezoelectric particle material in a specific route or pattern, and a grid-shaped structure is obtained after eluting the aggregated magnetic particle material or the piezoelectric particle material; Figure 3 Schematic diagram of an electron transport layer of a double-layer titanium dioxide grating structure with different rotation angles obtained in Example 1 of the present invention; Figure 4 Schematic diagram of step 23 and step 25 in embodiment 2 of the present invention; Figure 5 Schematic diagram showing the performance comparison between the perovskite solar cell with a complex light-harvesting structure prepared in Example 2 of the present invention and the existing perovskite solar cell without a light-harvesting structure. DETAILED DESCRIPTION

[0007] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0008] Please also refer to Figure 1 as well as Figure 2 As shown, a preferred embodiment of the method for structuring the functional layer of a perovskite solar cell according to the present invention comprises the following steps: Magnetic granular materials with different magnetization strengths or piezoelectric (ferroelectric) granular materials A with different piezoelectric coefficients are mixed with the materials for preparing the functional layer of the perovskite solar cell to obtain a mixed solution, and then the mixed solution is coated on the surface of the substrate 1 to prepare the functional layer to obtain a liquid film 2, and then a magnetic field or electric field in a specific direction is applied to the coated liquid film 2 to make the magnetic granular material or piezoelectric granular material A gather and arrange according to a specific route or pattern, and then anneal the liquid film to solidify it, and then wash out the magnetic granular material or piezoelectric granular material A in the functional layer 3. Finally, the washed functional layer 3 is dried to obtain a functional layer after structured processing. After drying, the liquid film 2 becomes the functional layer 3.

[0009] The functional layer 3 is at least one of an electrode layer, a carrier transport layer and a perovskite light absorption layer, wherein the carrier transport layer includes a hole transport layer and an electron transport layer.

[0010] Furthermore, in the mixed solution, the volume percentage of the magnetic particle material or the piezoelectric particle material A in the mixed solution is 20 vol% to 60 vol%.

[0011] Furthermore, the magnetic particle material or piezoelectric particle material A does not chemically react with the material for preparing the functional layer and is not miscible with each other. Therefore, in the mixed solution, the magnetic particle material or piezoelectric particle material A is in a state of irregular arrangement.

[0012] Furthermore, the magnetic particle material includes ferroferric oxide (Fe3O4), γ-iron oxide (γ-Fe2O3), iron oxide and barium oxide (BaO·6Fe2O3), iron oxide and lead oxide (PbO·6Fe2O3), iron-cobalt alloy (Fe-Co), iron-chromium alloy (Fe-Cr), cobalt ferrite (CoFe2O4), cobalt-zinc ferrite (Co 0.3 Zn 0.7 -Fe2O4) particles.

[0013] Furthermore, the magnetic particle material is magnetic fluid.

[0014] Specifically, the preparation method of the magnetic fluid is as follows: the magnetic block material is placed in a surfactant and crushed and ground into a granular material to obtain the desired magnetic fluid. The surfactant includes any one of kerosene, oleic acid, isopropyl alcohol, acetone, ethanol, oleylamine, and polyethylene glycol. The particle size of the magnetic fluid is regulated by controlling the crushing and grinding time.

[0015] Specifically, another method for preparing the magnetic fluid: Place the magnetic bulk material in an alkaline solution, then mix it with a surfactant, and then heat the mixed solution. The magnetic bulk material undergoes a hydrolysis reaction with the alkaline solution, and the required magnetic fluid is obtained when no more gas is generated. Among them, the surfactant includes any one of kerosene, oleic acid, isopropyl alcohol, acetone, ethanol, oleylamine, and polyethylene glycol. The particle size of the magnetic fluid is controlled by adjusting conditions such as the concentration of the alkaline solution, hydrolysis time, hydrolysis temperature, and surfactant.

[0016] Further, the piezoelectric (ferroelectric) particle material includes at least one of barium titanate (BTO), lead zirconate titanate (PZT), strontium titanate (STO), bismuth ferrite (BFO), trimethylfluoromethylammonium cadmium trichloride [(TMFM)CdCl3], trimethylchloromethylammonium cadmium trichloride [(TMCM)CdCl3], (trimethylfluoromethylammonium-trimethylchloromethylammonium) cadmium trichloride [(TMFM) x (TMCM)1-xCdCl3 (0 < x < 1)], cadmium tetramethylphosphine trichloride {[(CH3)4P]CdCl3}, quinuclidine periodate (C7H 14 NO4I), imidazoline perchlorate (C3N2H5ClO4), dibenzylamine lead chloride, polyvinylidene fluoride (PVDF), poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] particles.

[0017] Further, the method also includes pre-surface modification treatment of the magnetic particle material or the piezoelectric particle material. The surface modification treatment method includes: performing a coordination reaction between the magnetic particle material or the piezoelectric particle material A and a phosphoric acid-based dispersant or a carboxylic acid-based dispersant or an alcohol-based dispersant to obtain particles with different hydrophilicities.

[0018] After the magnetic particle material or the piezoelectric particle material A undergoes surface modification treatment, a surface modification layer is attached to its outer surface, which can quickly respond to an electric field or a magnetic field and has good compatibility with the eluent, so that the patterned magnetic particle material or piezoelectric particle material can be quickly eluted.

[0019] Further, the phosphoric acid-based dispersant is any one of n-hexadecylphosphoric acid, n-octadecylphosphoric acid, dodecylphosphonic acid-nitrogen, nitrogen-dimethyl-n-octadecylammonium bromide, and heptadecafluorooctane phosphoric acid; the carboxylic acid-based dispersant is any one of dodecanoic acid, heptadecanoic acid, and mercaptobutyric acid; the alcohol-based dispersant is any one of trimethylsilanol, poly(o-diphenol), polyvinyl acetate, and carrageenan.

[0020] The following further illustrates the method for structuring the functional layer of the perovskite solar cell of the present invention through specific examples. Example 1

[0021] Please refer to Figure 3 As shown, the first embodiment of the method for structuring the functional layer of a perovskite solar cell of the present invention comprises the following steps: Step 11: Prepare a titanium dioxide planar layer on the surface of the FTO substrate by spin coating. Specifically, a 0.3M butanol solution of diisopropyl diacetylacetonate titanate is added dropwise to the surface of the FTO glass substrate at a rotation speed of 2000 rpm / min and an acceleration of 1000 rpm / s. 2 The spin coating time was 60s. After spin coating, the substrate was heated at 150°C for 10min and then at 500°C for 30min.

[0022] Step 12: Mix the magnetic nanoparticles of γ-iron oxide (γ-Fe2O3), iron oxide lead oxide (PbO·6Fe2O3) and iron-cobalt alloy (Fe-Co) with n-hexadecyl phosphoric acid, with a solid concentration of 90wt% and a molar ratio of 3:2:1, stir evenly and set aside. Add the prepared mixed solution into the titanium dioxide precursor solution at a volume ratio of 60%, and mix and stir.

[0023] Step 13, coating the mixed precursor liquid prepared in step 12 on the titanium dioxide plane layer, and after coating, applying a strip magnetic field with a strength of 60Oe and a width of 0.4μm perpendicular to the plane of the substrate to the liquid film on the substrate at a spacing of 0.5μm. Under the action of the magnetic field, the magnetic particles are arranged in a longitudinal strip shape in the precursor liquid film space, and finally form a suspended stripe formed by stacking the above magnetic particles with a width of about 0.2μm and a depth of about 500nm covering the plane of the substrate, and the upper surface of the magnetic particles is tangent to the upper surface of the liquid film.

[0024] Step 14, maintaining the external magnetic field state, annealing the titanium dioxide liquid film prepared in step 13 at 150° C. for 30 min to solidify it, obtaining a titanium dioxide layer with stripes of 0.2 μm in width, 0.3 μm in spacing, and 500 nm in depth, and removing the external magnetic field.

[0025] Step 15: Use an eluent such as water, acetone or ethanol to wash away the magnetic material accumulated in the titanium dioxide layer.

[0026] Step 16: Dry the titanium dioxide layer at 450° C. for 1 hour to obtain a titanium dioxide layer B having a desired grating structure. The grating spacing is 0.3 μm, which is recorded as d1.

[0027] Step 17, repeating steps 11 to 13, except that the titanium oxide component in step 11 is replaced with a perovskite component, changing the direction of the magnetic field in step 13, rotating it clockwise by an angle of θ of 60°, and repeating steps 14 to 16, except that the eluent is isopropanol, and the annealing and drying temperature is 200°C, to obtain another perovskite layer C with a grating structure, and the grating spacing is d2. Finally, a light-absorbing layer with a double-layer perovskite grating structure with different rotation angles is obtained.

[0028] Step 18: Subsequently, the hole transport layer and the top electrode are prepared to obtain a perovskite solar cell having a double-layer light-harvesting structure.

[0029] This embodiment prepares a perovskite cell light-absorbing layer containing a double-layer grating structure with different rotation angles, wherein the first layer is a grating layer that does not rotate, and the second layer is a grating layer with a rotation angle θ of 60°. This embodiment performs a structured treatment on the perovskite light-absorbing layer of the perovskite solar cell. This structure extends the optical path, causes the light to be refracted multiple times in the perovskite light-absorbing layer, and improves the utilization rate of the spectrum. Example 2

[0030] Please refer to Figure 4 As shown, the second embodiment of the method for structuring the functional layer of a perovskite solar cell of the present invention provides a light trapping structure layer on the bottom electrode, specifically comprising the following steps: Step 21: Prepare a glass substrate 1.

[0031] Step 22: Add 70wt% of barium titanate (BTO), lead zirconate titanate (PZT), and strontium titanate (STO) of ferroelectric particle material A into ITO nanoparticle precursor solution (15wt%, ethanol solution), and the molar ratio of the three ferroelectric materials is 3:2:1. The ITO precursor solution solvent system will not destroy the ferroelectric structure, and mix and stir.

[0032] Step 23, coating the mixed precursor liquid on the substrate 1, after coating, applying a strip electric field perpendicular to the substrate plane with a strength of 200V / m, a width of 0.2μm, and an interval of 0.5μm to the substrate at a spacing of 1cm. Under the action of the electric field, the ferroelectric particles are arranged in strips and layers in the precursor liquid film space, forming inverted triangular micro-prisms of ferroelectric particles with a width of 0.2μm, a depth of 100nm, and a periodic arrangement of 0.5μm intervals covering the substrate plane, and the prism near the electric field generator surface is tangent to the upper surface of the liquid film.

[0033] Step 24, maintaining the external electric field, annealing the ITO liquid film 2 at 200° C. for 15 min to obtain an ITO layer, and removing the electric field.

[0034] Step 25: Use NN, dimethylformamide, an elution solvent, to wash away the ferroelectric material that has accumulated in the ITO layer.

[0035] Step 26: anneal the ITO layer at 250° C. for 10 min to obtain the desired light trapping structure layer 4 on the surface of the ITO layer.

[0036] Step 27, continue to prepare the first carrier transport layer, the perovskite light absorption layer, the second carrier transport layer and the top electrode layer on the surface of the ITO layer having the light trapping structure layer 4 to obtain a perovskite solar cell having an inverted triangle-shaped light trapping structure layer 4.

[0037] exist Figure 4 The figure shows a schematic diagram of how, under the action of an electric field, the ferroelectric particles in the mixed precursor liquid coated on the ITO planar layer substrate are arranged in strips and layers in the precursor liquid film space to form a light-trapping morphology, as well as a schematic diagram showing how the desired ITO light-trapping structure layer is obtained after the aggregated ferroelectric particles are washed away.

[0038] exist Figure 5 It is shown in the figure that the perovskite solar cell with a complex light-harvesting structure prepared in this embodiment has a higher current density than the existing perovskite solar cell without a light-harvesting structure, and shows higher light utilization and light capture efficiency.

[0039] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for structuring a functional layer of a perovskite solar cell, characterized in that: The steps include: Magnetic granular materials with different magnetization strengths or piezoelectric granular materials with different piezoelectric coefficients are mixed with materials for preparing the functional layer of a perovskite solar cell to obtain a mixed solution, and then the mixed solution is coated on the surface of a substrate to be prepared for the functional layer to obtain a liquid film, and then a magnetic field or an electric field in a specific direction is applied to the coated liquid film to arrange the magnetic granular materials or the piezoelectric granular materials in a specific route or pattern, and then the liquid film is solidified by annealing, and then the magnetic granular materials or the piezoelectric granular materials in the functional layer are eluted, and finally the eluted functional layer is dried to obtain a functional layer after structured processing; wherein the functional layer is at least one of an electrode layer, a carrier transport layer and a perovskite light absorption layer, and the carrier transport layer includes a hole transport layer and an electron transport layer.

2. The method for structuring the functional layer of a perovskite solar cell according to claim 1, characterized in that: In the mixed solution, the volume percentage of the magnetic particle material or the piezoelectric particle material in the mixed solution is 20 vol% to 60 vol%.

3. The method for structuring the functional layer of a perovskite solar cell according to claim 1, characterized in that: The magnetic particle material or the piezoelectric particle material does not chemically react with the material for preparing the functional layer and is not miscible with each other.

4. The method for structuring the functional layer of a perovskite solar cell according to claim 1, characterized in that: The magnetic particle material includes at least one particle of ferrosoferric oxide, γ-iron oxide, iron oxide combined with barium oxide, iron oxide combined with lead oxide, iron-cobalt alloy, iron-chromium alloy, cobalt ferrite, and cobalt-zinc ferrite.

5. The method for structuring the functional layer of a perovskite solar cell according to claim 1, characterized in that: The magnetic particle material is magnetic fluid.

6. The method for structuring the functional layer of a perovskite solar cell according to claim 5, characterized in that: The preparation method of the magnetic fluid comprises the following steps: placing a magnetic block material in a surfactant, crushing and grinding it into a granular material, and then obtaining the desired magnetic fluid; wherein the surfactant comprises any one of kerosene, oleic acid, isopropanol, acetone, ethanol, oleylamine, and polyethylene glycol.

7. The method for structuring the functional layer of a perovskite solar cell according to claim 5, characterized in that: The preparation method of the magnetic fluid comprises the following steps: placing a magnetic block material into an alkaline solution, mixing the magnetic block material with a surfactant, and then heating the mixed solution, so that the magnetic block material and the alkaline solution undergo a hydrolysis reaction, and when no gas is generated, the desired magnetic fluid is obtained; wherein the surfactant comprises any one of kerosene, oleic acid, isopropyl alcohol, acetone, ethanol, oleylamine, and polyethylene glycol.

8. The method for structuring the functional layer of a perovskite solar cell according to claim 1, characterized in that: The piezoelectric particle material includes at least one particle of barium titanate, lead zirconate titanate, strontium titanate, bismuth ferrite, trimethylfluoromethylammonium cadmium trichloride, trimethylchloromethylammonium cadmium trichloride, (trimethylfluoromethylammonium-trimethylchloromethylammonium) cadmium trichloride, cadmium trichloride tetramethylphosphine, quinuclidine periodate, imidazoline perchlorate, dibenzylamine lead chloride, polyvinylidene fluoride, and vinylidene fluoride-trifluoroethylene copolymer.

9. The method for structuring the functional layer of a perovskite solar cell according to claim 1, characterized in that: The method also includes pre-surface modification of the magnetic particle material or the piezoelectric particle material, and the surface modification method includes: coordinating the magnetic particle material or the piezoelectric particle material with a phosphoric acid dispersant, a carboxylic acid dispersant or an alcohol dispersant to obtain particles with different hydrophilicities.

10. The method for structuring the functional layer of a perovskite solar cell according to claim 9, characterized in that: The phosphoric acid dispersant is any one of n-hexadecyl phosphoric acid, n-octadecyl phosphoric acid, dodecylphosphonic acid-nitrogen, nitrogen-dimethyl-nitrogen-octadecylamine bromide, and heptadecafluorophosphate; the carboxylic acid dispersant is any one of dodecanoic acid, heptadecanoic acid, and mercaptobutyric acid; and the alcohol dispersant is any one of trimethylsilanol, poly(o-diphenol), polyvinyl acetate, and carrageenan.

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