CN110246969B

CN110246969B - Preparation method of perovskite solar cell with pyridine modified tin oxide compact layer

Info

Publication number: CN110246969B
Application number: CN201910549951.7A
Authority: CN
Inventors: 李天朋; 范心怡; 张晓坤; 李斌; 芮一川
Original assignee: Shanghai University of Engineering Science
Current assignee: Shanghai University of Engineering Science
Priority date: 2019-06-24
Filing date: 2019-06-24
Publication date: 2023-04-28
Anticipated expiration: 2039-06-24
Also published as: CN110246969A

Abstract

The invention relates to a preparation method of a perovskite solar cell with a pyridine modified tin oxide compact layer, which comprises the following steps: (1) Taking SnCl ₂ ﹒2H ₂ Mixing O with isopropanol solution, heating to obtain clear sol, and refrigerating for use; (2) spin coating the clear sol on the surface of the FTO, and heating and annealing; (3) Placing the annealed FTO in ozone for treatment, spin-coating pyridine solution, and heating and annealing to obtain pyridine modified FTO; (4) And then coating the surface of the pyridine modified FTO with perovskite precursor solution, heating and annealing, and then continuously spin-coating the Spiro-OMeTAD solution, and plating gold to finish the preparation. Compared with the prior art, the invention has low cost of raw materials, no special requirement in the experimental process, and can improve the battery performance by simply modifying the tin oxide compact layer, and the like.

Description

Preparation method of perovskite solar cell with pyridine modified tin oxide compact layer

Technical Field

The invention belongs to the technical field of perovskite solar cells, and relates to a preparation method of a perovskite solar cell with a pyridine modified tin oxide compact layer.

Background

The perovskite solar cell is a third-generation novel thin-film solar cell and has the advantages of longer carrier diffusion length, higher light absorption coefficient, low cost, high efficiency and the like. Typical perovskite solar cell structures include transparent conductive glass (FTO), an n-type dense electron transport layer, an organic-inorganic perovskite layer, a P-type hole transport layer, and a metal back electrode. The stability of perovskite solar cells depends on the structure and morphology of the electron transport layer. The electron transport layer is also called an electron extraction layer or an electron collection layer. Electrons are extracted from the perovskite layer, pass through the electron transport layer, and are finally collected by the back electrode. TiO (titanium dioxide) ₂ The dense layer is the most widely used electron transport layer at present, however mesoporous layer TiO ₂ After the addition, defect points are increased, electron coincidence is increased, and the defects are not beneficial to the stability of the perovskite solar cell and the preparation of the high-efficiency solar cell. In addition, tiO ₂ The electron mobility is relatively low and has to be annealed at 500 c, limiting its application to flexible materials.

In recent years, research has found that modification of the perovskite layer or the electron transport layer is beneficial to improving the interface structure, accelerating electron transport and improving the battery efficiency. The invention of application number CN201810795179.2 discloses a method for preparing a high-efficiency stable perovskite solar cell by adding a surfactant into a perovskite layer, wherein the perovskite layer is prepared by adjusting the content of a cationic surfactant in a perovskite precursor solution, so that the surface defects of a perovskite layer film are reduced, and the morphology and crystallinity of the perovskite layer are improved. While improving battery efficiency and stability. The invention of application number CN201711281995.3 discloses a perovskite type solar cell and a modification method of a PEDOT: PSS layer of the perovskite type solar cell. The patent increases the electron injection efficiency and the stability of perovskite by using one of weakly basic metal oxide, amino acid and mercaptan, inhibits the generation of perovskite yellow phase of FAI, and has low material price, simple and convenient operation method and easy control. However, the modification process has more influencing factors, is difficult to operate and has still low efficiency.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a preparation method of a perovskite solar cell with a pyridine modified tin oxide compact layer. The pyridine modified tin oxide compact layer is used as an electron transport layer, so that the electron extraction speed can be further increased, and the contact surface between the electron transport layer and the perovskite layer is improved. Thereby contributing to the improvement of the photoelectric conversion efficiency of perovskite.

The aim of the invention can be achieved by the following technical scheme:

the preparation method of the perovskite solar cell with the pyridine modified tin oxide compact layer comprises the following steps:

(1) Taking outSnCl ₂ ﹒2H ₂ Mixing O with isopropanol solution, heating to obtain clear sol, and refrigerating for use;

(2) Spin-coating the clear sol obtained in the step (1) on the surface of the FTO, and heating and annealing;

(3) Placing the FTO which is annealed in the step (2) in ozone for treatment for 15min, spin-coating pyridine solution, and heating and annealing to obtain pyridine modified FTO;

(4) And (3) coating the surface of the pyridine modified FTO in the step (3) with a perovskite precursor solution, heating and annealing, and then continuously spin-coating a Spiro-OMeTAD (2, 2', 7' -tetrakis [ N, N-bis (4-methoxyphenyl) amino ] -9,9' -spirobifluorene) solution, and plating gold to finish the preparation.

Further, in the step (1), the heating temperature was 70℃and the time was 1h.

Further, in the step (1), snCl ₂ ﹒2H ₂ The ratio of O to isopropanol solution was 225.65mg:10ml of isopropanol solution was present at a concentration of 99.7wt%.

Further, in the step (2), the FTO is firstly ultrasonically cleaned for 30min by using a glass detergent, deionized water and ethanol; the temperature of the heating annealing is 200 ℃ and the time is 30min.

Further, in the step (3), the ozone treatment time is 30min;

the pyridine solution is a solution containing pyridine, dithiopyridine, 4-tert-butylpyridine or vinyl pyridine as solute, and has a coating amount of 25 μl and a surface area of 4cm corresponding to FTO ^-2 . The concentration of the pyridine solution varies depending on the kind of solute, for example, when the solute is pyridine, the concentration is 99.6wt%, dithiopyridine 0.1M, 4-t-butylpyridine 0.1M or vinylpyridine 0.1 to 0.2M.

Further, in the step (3), the temperature of the heating annealing is 70-85 ℃ and the time is 30min.

Further, the perovskite precursor solution is an organic solvent mixed solution of perovskite light absorbing materials, wherein the perovskite light absorbing materials are cesium lead iodides, methyl ether lead iodides or methyl ammonium lead iodides.

Further, in the step (4), the process conditions of the thermal annealing are as follows: annealing at 90-100deg.C for 10-30min.

Further, the concentration of the Spiro-OMeTAD solution is 72.8mg/ml, the solvent is chlorobenzene superior purity, the coating amount is 25 mu L, and lithium salt and 4-tertiary butyl pyridine are also added into the solution.

SnCl ₂ ﹒2H ₂ O is added into isopropanol solution to form a precursor solution of a clear and transparent electron transport layer after heating and refluxing, snO ₂ The particle size is uniform and the dispersibility is good. The electron transport layer is configured to accept electrons from the perovskite layer, which is spin-coated from a perovskite precursor solution, and to generate electron-hole pairs when irradiated with solar light, while the Spiro-ome tad receives holes from the perovskite layer. The entire perovskite solar cell structure appears as a sandwich structure.

The invention relates to an FTO surface and SnO ₂ The surface ozone treatment of the compact layer surface, the spin-coated pyridine and the homologs thereof aims to remove the organic impurities on the surface of the compact layer surface respectively, so that the surface is more uniform and smoother; spin-coating SnO ₂ The compact layer is annealed at 200 ℃ for 30min at too high temperature and SnO ₂ Cracks can appear on the surface to affect the stability of the whole battery device, and when the temperature is too low, snO ₂ The surface defects are more, the electron transmission is affected, the electric leakage phenomenon is generated, and too many defects are generated in the tin oxide compact layer due to too long and too short time; the annealing temperature of the pyridine modification layer is 70-85 ℃ and the annealing time is 30min, because the boiling point of pyridine is 98 ℃, if the pyridine modification layer is too low in stability, the surface of the pyridine modification layer film is uneven, and the performance of a device is affected; annealing the perovskite layer at 90-100 ℃ for 10-30min, wherein the internal structure of the perovskite is damaged due to the fact that the perovskite layer is excessively high in temperature, so that the photoelectric conversion efficiency of the battery is affected, the perovskite layer is incompletely crystallized due to the fact that the perovskite layer is low in temperature, the photoelectric conversion efficiency of the battery is also affected, and the stability of the battery is lowered; the gold plated was used as an electrode.

Since tin oxide has hygroscopicity and can cause perovskite decomposition in an air environment, a thin film can be formed on the surface of tin oxide by pyridine modification. The interface between tin oxide and perovskite is improved, and the efficiency and stability of the battery device are further improved.

The nitrogen atom and the carbon atom on the pyridine ring form sigma bonds through sp2 hybridization orbitals, and a planar six-membered ring is formed. One p-orbital per atom is perpendicular to the ring plane and one electron per p-orbital, which more readily receives electrons from the perovskite layer. These p orbitals overlap laterally to form a closed large pi bond. In pyridine molecule, nitrogen atom has a pair of lone pair electrons, and can fix Pb in perovskite layer ²⁺ The defects of the perovskite layer are reduced, the surface is improved, and finally the efficiency is improved.

Compared with the prior art, the invention has the following advantages:

(1) The method for modifying the tin oxide electron transport layer by pyridine is simple, and the method does not need to be in a special environment without water and oxygen in a glove box.

(2) The preparation processes of the battery can be carried out under the low-temperature condition, so that high-temperature sintering is avoided, and the battery can be used for preparing the flexible solar battery.

(3) The nitrogen atom on the pyridine ring has a pair of lone pair electrons, and can interact with the heavy metal ions of the perovskite layer, so that the surface defects are reduced, and the battery efficiency is improved.

(4) The invention uses the pyridine modified tin oxide compact layer as the electron transport layer, which has excellent performance and can improve the battery efficiency to 12.7%.

Drawings

FIG. 1 is a field emission scanning electron microscope image of a prepared dense layer of pyridine modified tin oxide;

FIG. 2 is a side field emission scanning electron microscope image of the prepared pyridine modified tin oxide compact layer;

FIG. 3 is a current-voltage curve of a perovskite solar cell of a dense layer of pyridine modified tin oxide prepared in example 1;

FIG. 4 is a current-voltage curve of a perovskite solar cell of a dense layer of tin oxide prepared as comparative example 1;

FIG. 5 is a field emission scanning electron microscope image of a side of a perovskite solar cell with a dense layer of pyridine modified tin oxide prepared in example 1;

FIG. 6 is a graph of current versus voltage for a perovskite solar cell having a dense layer of pyridine modified tin oxide prepared in example 2;

FIG. 7 is a side field emission scanning electron microscope image of a perovskite solar cell with a dense layer of pyridine modified tin oxide prepared in example 2.

Detailed Description

The invention will now be described in detail with reference to the drawings and specific examples. The present embodiment is implemented on the premise of the technical scheme of the present invention, and a detailed implementation manner and a specific operation process are given, but the protection scope of the present invention is not limited to the following examples.

In the following examples, the sources of the reagents, which are the raw materials used, are shown in Table 1.

Raw materials and reagents used in Table 1

/>

In addition, the spin-coating of solutions such as Spiro-OMeTAD is also a conventional method in the art, the gold plating process is also a conventional gold plating process in the art (a vacuum plating apparatus is used to plate a gold electrode with a layer thickness of about 80 nm), and the remainder, unless specifically indicated, represents a conventional commercial product or conventional technique.

Example 1

(1) 225.65mg SnCl is taken ₂ ﹒2H ₂ O was used as a raw material for preparing the tin oxide precursor solution, followed by adding 10mL of an isopropyl alcohol solution (99.7 wt%) and mixing and stirring in a water bath, and stirring by reflux at 70℃for one hour. Heating to clarify the sol.

(2) After refrigerating the prepared clear sol, spin-coating 25. Mu.L on FTO (the FTO is respectively ultrasonically cleaned with glass detergent, deionized water and ethanol for 30 min). Heated on a hot plate at 200℃for half an hour.

(3) The FTO after annealing in step (2) was treated with ultraviolet ozone for 30min, followed by spin-coating 25. Mu.L of pyridine solution (99.6 wt%) and after heating in an oven at 85℃for half an hour, ozone was applied for 15 min.

(4) Coating the surface of the dense layer of tin oxide modified with pyridine in step (3) with a perovskite precursor solution, i.e. PbI ₂ The solution with the concentration of 1.1mol/L (DMF (N, N-dimethylformamide): DMSO (dimethyl sulfoxide) =4:1) is annealed at 100 ℃ for 30min, and then spin-coated with the solution with the concentration of Spiro-OMeTAD, and gold plating is carried out, so that the battery preparation is completed.

Fig. 1 is a field emission scanning electron microscope image of the dense layer of tin oxide modified with pyridine prepared in example 1, and fig. 2 is a side field emission scanning electron microscope image of the dense layer of tin oxide modified with pyridine prepared in example 1. As can be seen from FIG. 1, the surface of the dense layer of tin oxide modified with pyridine is smooth and uniform, and the light transmittance is very good. As can be seen from fig. 2, the thickness of the prepared dense layer of tin oxide modified with pyridine is about 30nm, which is an ideal dense layer for preparing perovskite solar cells.

Fig. 3 is a graph of current versus voltage for a perovskite solar cell using a dense layer of pyridine modified tin oxide as the electron transport layer prepared in example 1, resulting in a short circuit current density of 20.95 milliamp per square centimeter, a fill factor of 56.98%, a cell open circuit voltage of 1.11 volts, and a photoelectric conversion efficiency of 13.26%.

Fig. 5 is a cross-sectional view of a perovskite solar cell using a dense layer of pyridine modified tin oxide as an electron transport layer prepared in example 1. From the figure it can be seen that the perovskite layer is approximately 450nm thick and the hole transport layer is approximately 200nm. The layers are closely contacted, so that electron extraction and transmission are facilitated.

Comparative example 1

The procedure was as in example 1, except that the pyridine was not used to modify the tin oxide. As can be seen from fig. 4, the current-voltage curve of the perovskite solar cell using the tin oxide dense layer prepared in comparative example 1 as the electron transport layer, obtained a short-circuit current density of 20.45 milliamperes per square centimeter, a fill factor of 57.83%, a cell open-circuit voltage of 1.05 volts, a photoelectric conversion efficiency of 12.45%, and various degrees of reductions in the main parameters of the cell, such as open-circuit voltage, photoelectric conversion efficiency, and current density.

Example 2

(1) 225.65mg SnCl is taken ₂ ﹒2H ₂ O is used as a raw material for preparing the tin oxide precursor solution, and then isopropanol solution is added, mixed and stirred in a water bath, and stirred at 70 ℃ for one hour through reflux. Heating to clarify the sol.

(2) After the prepared precursor solution was refrigerated, 25. Mu.L was spin-coated on FTO (the FTO was ultrasonically cleaned with glass detergent, deionized water, ethanol, respectively, for 30 min). The mixture was heated on a hot plate at 200℃for half an hour.

(3) After the FTO after the annealing in the step (2) is conducted for 30min, 25 mu L of 0.1M dithiopyridine solution is spin-coated, and after heating for 30min in an oven at 70 ℃, the FTO is conducted for 15 min.

(4) Coating the surface of the dense layer of tin oxide modified with pyridine in step (3) with a perovskite precursor solution of PbI ₂ 1.1mol/L (DMF (N, N-dimethylformamide): DMSO (dimethyl sulfoxide) =4:1), 25 μl, annealing at 90deg.C for 20min, spin-coating Spiro-OMeTAD, gold plating,

fig. 6 is a graph of current versus voltage for a perovskite solar cell using a dense layer of pyridine modified tin oxide as the electron transport layer prepared in example 2, resulting in a short circuit current density of 20.34 milliamperes per square centimeter, a fill factor of 64.45%, a cell open circuit voltage of 0.97 volts, and a photoelectric conversion efficiency of 12.75%.

Fig. 7 is a field emission scanning electron microscope image of a perovskite solar cell using a dense layer of pyridine modified tin oxide as an electron transport layer, which is prepared in example 2, and it can be seen from the image that the perovskite layer and the electron transport layer, and the hole transport layer are in good contact with each other, so that the electron mobility can be effectively improved.

Example 3

(1) 225.65mg SnCl is taken ₂ .2H ₂ O was used as a raw material for preparing the tin oxide precursor solution, followed by adding 10mL of isopropyl alcohol solution (99.7%) and mixing and stirring in a water bath, and stirring by reflux at 70℃for one hour. Heating to clarify the sol.

(3) The annealed FTO in (2) was ozonated for 30min, followed by spin-coating with 25. Mu.L of 0.1M tetra-t-butylpyridine solution, and after heating in an oven at 70℃for half an hour, ozonated for 15 min.

(4) Coating the surface of the dense layer of tin oxide modified with pyridine in (3) with a perovskite precursor solution of PbI ₂ The concentration is 1.1mol/L (the solvent is DMF (N, N-dimethylformamide): DMSO (dimethyl sulfoxide) =4:1), the spin coating is 25 mu L, the annealing is carried out at 100 ℃ for 20min, the spin-coating is carried out on the alloy, the gold plating is carried out,

example 4

(1) 225.65mg SnCl is taken ₂ ﹒2H ₂ O was used as a raw material for preparing the tin oxide precursor solution, followed by adding 10mL of isopropyl alcohol solution (99.7%) and mixing and stirring in a water bath, stirring at 70℃for one half hour by reflux. Heating to clarify the sol.

(3) The annealed FTO in step (2) was ozonated for 30min, followed by spin-coating 26. Mu.L of pyridine solution (99.6%), heating in an oven at 70℃for half an hour, followed by additional ozone for 20 min.

(4) Coating the surface of the dense layer of tin oxide modified with pyridine in step (3) with a perovskite precursor solution of PbI ₂ The concentration is 1.1mol/L (the solvent is DMF (N, N-dimethylformamide): DMSO (dimethyl sulfoxide) =4:1), the spin coating is 25 mu L, the annealing is carried out at 100 ℃ for 20min, the spin-coating is carried out on the alloy, the gold plating is carried out,

example 5

(3) The annealed FTO ozone in step (2) was spun on 25. Mu.L of 0.1M/L vinylpyridine solution for 20min, and after heating in an oven at 70℃for half an hour, ozone was applied for 15min and ozone was applied for 15 min.

example 6

(1) 225.65mg SnCl is taken ₂ ﹒2H ₂ O was used as a raw material for preparing the tin oxide precursor solution, followed by adding 10mL of isopropyl alcohol solution (99.7%) and mixing and stirring in a water bath, and stirring by reflux at 70℃for one hour. Heating to clarify the sol.

(3) The annealed FTO in step (2) was ozonated for 30min, followed by spin-coating 25. Mu.L of 0.1M/L vinylpyridine solution, and after heating in an oven at 70℃for half an hour, ozonated for 15 min.

(4) Coating the surface of the dense layer of tin oxide modified with pyridine in step (3) with a perovskite precursor solution (PbI ₂ 1.1mol/L, DMF (N, N-dimethylformamide) as solvent: DMSO (dimethyl sulfoxide) =4:1), spin-coated 25 μl, annealed at 100 ℃ for 20min, spin-coated Spiro-ome, gold plated.

Example 7

(1) 225.65mg SnCl is taken ₂ ﹒2H ₂ O was used as a raw material for preparing the tin oxide precursor solution, followed by adding 10mL (isopropyl alcohol solution (99.7%) and mixing and stirring in a water bath, and refluxing at 70 DEG CStirring was carried out for one hour. Heating to clarify the sol.

(3) The annealed FTO in step (2) was ozonated for 30min, followed by spin-coating 25. Mu.L of 0.2M/L vinylpyridine solution, and after heating in an oven at 70℃for half an hour, ozonated for 15 min.

(4) Coating the surface of the dense layer of tin oxide modified with pyridine in step (3) with a perovskite precursor solution (PbI ₂ The concentration is 1.1mol/L, and the solvent is DMF (N, N-dimethylformamide): DMSO (dimethyl sulfoxide) =4:1), spin-coated 25 μl, annealed at 100 ℃ for 20min, spin-coated Spiro-ome, gold plated.

Example 8

(3) The annealed FTO in (2) was ozonated for 30min, followed by spin-coating with 25 μ L0.15M/L vinylpyridine solution, heating in an oven at 70℃for half an hour, and then ozonating for 15 min.

(4) Coating the surface of the dense layer of tin oxide modified with pyridine in (3) with a perovskite precursor PbI ₂ Solution, concentration 1.1mol/L (solvent DMF (N, N-dimethylformamide): DMSO (dimethyl sulfoxide) =4:1), spin-coating 25. Mu.L, annealing at 100deg.C for 20min, spin-coating Spiro-OMeTAD, gold plating.

In each of the above examples, the concentration of the Spiro-OMeTAD solution was 72.8mg/ml, the solvent was chlorobenzenesuper pure, and the coating amount was 25. Mu.L. Lithium salt and 4-tert-butylpyridine can be added into the Spiro-OMeTAD solution. The lithium salt was added as a 520mg/mL solution (acetonitrile as solvent) corresponding to 25. Mu.L of the Spiro-OMeTAD solution in an amount of 0.6. Mu.L and 0.735. Mu.L of 4-t-butylpyridine.

The previous description of the embodiments is provided to facilitate a person of ordinary skill in the art in order to make and use the present invention. It will be apparent to those skilled in the art that various modifications can be readily made to these embodiments and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above-described embodiments, and those skilled in the art, based on the present disclosure, should make improvements and modifications without departing from the scope of the present invention.

Claims

1. The preparation method of the perovskite solar cell with the pyridine modified tin oxide compact layer is characterized by comprising the following steps of:

(1) Taking SnCl ₂ ﹒2H ₂ Mixing O with isopropanol solution, heating to obtain clear sol, and refrigerating for use;

(3) Placing the FTO which is annealed in the step (2) in ozone for treatment, spin-coating pyridine solution, and heating and annealing to obtain pyridine modified FTO;

(4) Then coating perovskite precursor solution on the pyridine modified FTO surface in the step (3), heating and annealing, and then continuously spin-coating a Spiro-OMeTAD solution, and plating gold to finish the preparation;

in the step (3), the temperature of the heating annealing is 70-85 ℃ and the time is 30min.

2. The method for producing a perovskite solar cell with a dense layer of pyridine modified tin oxide according to claim 1, wherein in the step (1), the heating temperature is 70 ℃ and the time is 1h.

3. The method for producing a perovskite solar cell with a dense layer of pyridine modified tin oxide as claimed in claim 1, wherein in the step (1), snC is selected from the group consisting ofl ₂ ﹒2H ₂ The ratio of O to isopropanol solution was 225.65mg:10ml of isopropanol solution was present at a concentration of 99.7wt%.

4. The method for preparing a perovskite solar cell with a dense layer of pyridine modified tin oxide according to claim 1, wherein in the step (2), FTO is firstly ultrasonically cleaned for 30min by using glass detergent, deionized water and ethanol;

the temperature of the heating annealing is 200 ℃ and the time is 30min.

5. The method for preparing a perovskite solar cell with a dense layer of pyridine modified tin oxide according to claim 1, wherein in the step (3), the ozone treatment time is 30min;

the pyridine solution is a solution containing pyridine, dithiopyridine, 4-tert-butylpyridine or vinyl pyridine as solute, and has a coating amount of 25 μL/4cm ² FTO。

6. The method for preparing the perovskite solar cell with the pyridine modified tin oxide compact layer, according to claim 1, is characterized in that the perovskite precursor solution is an organic solvent mixed solution of perovskite light-absorbing materials, wherein the perovskite light-absorbing materials are cesium lead iodides, methyl ether lead iodides or methyl ammonium lead iodides.

7. The method for preparing a perovskite solar cell with a dense layer of pyridine modified tin oxide according to claim 1, wherein in the step (4), the process conditions of the heating annealing are as follows: annealing at 90-100deg.C for 10-30min.

8. The method for preparing a perovskite solar cell with a dense layer of pyridine modified tin oxide according to claim 1, wherein the concentration of the Spiro-ome tad solution is 72.8mg/ml.

9. The method for preparing a perovskite solar cell with a dense layer of pyridine modified tin oxide as claimed in claim 8, wherein lithium salt and 4-tert-butylpyridine are added into the Spiro-OMeTAD solution.