CN109326721B - Perovskite solar cell with high stability and liquid phase preparation method thereof - Google Patents

Abstract

The invention provides a perovskite solar cell with high stability and a liquid phase preparation method thereof, wherein the solar cell comprises the following components: transparent conductive glass, an electron transport layer, a mesoporous layer, an insulating support layer, a perovskite active layer and a carbon electrode layer; the solar cell is prepared by adopting a liquid phase method in natural air atmosphere, preparing a precursor liquid, taking transparent conductive glass as a substrate, and putting TiCl ₄ Treating with water solution, calcining to obtain electron transport layer, and spin-coating TiO on substrate ₂ Slurry and ZrO ₂ The slurry is dried and heat treated in time to prepare a mesoporous layer and an insulating bracket layer; dropwise adding a precursor solution into the substrate, heating to prepare a perovskite active layer, and scraping conductive carbon paste on the substrate to prepare a perovskite solar cell with high stability; the preparation of the inventionThe solar cell has high power conversion efficiency, stable long-term use performance, simple preparation process and low manufacturing cost, and can meet the requirement of large-scale industrialized production.

Description

A highly stable perovskite solar cell and its liquid phase preparation method

Technical field

The invention relates to the technical field of solar cells, and specifically to a low-cost, high-power conversion efficiency, high-stability perovskite solar cell based on carbon electrodes and a simple liquid-phase preparation method thereof.

Background technique

After entering the 21st century, with the rapid development of industry and economy, the energy crisis has become prominent. Therefore, it is imperative to develop clean renewable energy. As a pillar industry of the new generation of renewable energy, photovoltaic power generation has the advantages of cleanness, no pollution, and low cost. In recent years, new solar cells using perovskite as the light-absorbing layer have created a breakthrough in photovoltaic technology. Due to the advantages of perovskite materials such as high light absorption coefficient, controllable band gap, bipolarity (can transport both electrons and holes), long diffusion length and high carrier mobility, perovskite materials have better With excellent photoelectric performance, perovskite solar cells can achieve high power conversion efficiency. However, perovskite solar cells with high power conversion are currently prepared in high-purity glove boxes and use expensive hole transport layers and precious metal electrodes. Their high preparation costs and poor stability are not conducive to industrial mass production.

Chinese patent CN105870335A discloses a perovskite solar cell with a simple preparation process. It is based on a mesoporous scaffold structure device and simplifies the device structure. The carbon electrode replaces the expensive precious metal electrode, which improves the perovskite solar cell to a certain extent. Solar cell performance. However, the mesoporous scaffold layer and carbon electrode must be screen-printed and calcined to prepare the porous thin film electrode, which is then placed in a glove box and the perovskite precursor liquid is added dropwise. After penetrating into the mesoporous layer, the solvent is evaporated and crystallized to complete the preparation. . A glove box is used in the later stages of the preparation process, and the preparation process is not all completed under natural air.

Chinese patent CN106601833A discloses a low-cost and high-stability solar cell suitable for production and its preparation method. Although the power conversion efficiency of perovskite solar cells exceeds 16%, vacuum thermal evaporation, spraying, deposition and other methods are used, and finally vacuum evaporation of metal electrodes results in high device preparation costs, high requirements for preparation process conditions, and complex operations. And other issues. Although the above-mentioned invention patents have gradually promoted the industrialization of perovskite solar cells, perovskite solar cells are sensitive to oxygen and moisture, and defects are easy to form, resulting in poor stability of perovskite solar cells. Finding stable methods to prepare perovskite solar cells is a concerted effort in the field.

Chinese patent CN106328813A discloses a highly stable cesium-doped perovskite solar cell and its preparation method. This patent application improves device stability to a certain extent through cation doping, but introduces the expensive 2,2',7,7'-tetrakis[N,N-bis(4-methoxyphenyl)amino group ]-9,9'-Spiro-MeOTAD based hole transport layer. As a result, the device cost is high and the stability is still low.

It can be seen that by doping perovskite materials with cations, the crystallinity and stability can be enhanced, and the bandgap width of the perovskite materials can be adjusted at the same time, which can ultimately improve the power conversion efficiency and stability of perovskite solar cells. Therefore, for In view of the shortcomings of the above-mentioned prior art, the present invention provides a highly stable perovskite solar cell based on carbon electrodes under natural air and a simple liquid phase preparation method with low cost.

Contents of the invention

The purpose of the present invention is to overcome the shortcomings of the existing technology in the preparation of perovskite solar cells, propose an optimization of the device structure, do not use expensive materials, and use a simple liquid phase method to prepare high-stability perovskite solar cells under natural air conditions. Battery solution. The perovskite solar cell prepared by the invention has the advantages of high power conversion efficiency, long-term stability under natural air conditions, simple preparation process and low manufacturing cost, and can meet the requirements of large-scale industrial production.

In order to achieve the above objects, the present invention provides the following technical solutions:

A highly stable perovskite solar cell. Preferably, the perovskite solar cell includes: transparent conductive glass, electron transport layer, mesoporous layer, insulating support layer, perovskite active layer and carbon electrode layer;

The perovskite active layer is a mixed cation perovskite.

For the perovskite solar cell as described above, preferably, the perovskite active layer is prepared by a one-step spin coating method, and the perovskite active layer is a mixed cation perovskite (FA) _x ( MA) _1-x PbI ₃ , where x is the amount fraction of the substance;

Preferably, x in the mixed cationic perovskite (FA) _x (MA) _1-x PbI ₃ is 0.05 to 0.45;

Preferably, the mixed cation perovskite (FA) _x (MA) _1-x PbI ₃ includes methylamine cations and methylamine cations;

Preferably, the perovskite active layer penetrates and fills into the mesoporous layer and the insulating scaffold layer, and covers the surface of the insulating scaffold layer;

Preferably, the thickness of the perovskite active layer is 300-700 nm.

For the perovskite solar cell as described above, preferably, the transparent conductive glass is FTO conductive glass; the electron transport layer is a nano TiO ₂ layer; the mesoporous layer is a mesoporous TiO ₂ layer; and the insulating support layer It is a porous ZrO ₂ layer; the carbon electrode layer is a hydrophobic carbon electrode.

For the perovskite solar cell as mentioned above, preferably, the thickness of the electron transport layer is 10-40 nm; the thickness of the mesoporous layer is 150-300 nm; the thickness of the insulating support layer is 150-300 nm; The thickness of the carbon electrode layer is 8 to 20 μm.

The liquid phase preparation method of perovskite solar cells as described in any one of the above, preferably, the liquid phase preparation method is to use spin coating and blade coating liquid phase methods to complete all preparation processes in a natural air atmosphere; The liquid phase preparation method includes the following steps:

1) Preparation of mixed cationic perovskite precursor liquid

Prepare mixed cationic perovskite (FA) _x (MA) _1-x PbI ₃ precursor solution according to a certain amount of substances for later use;

2) Preparation of transparent conductive glass/electron transport layer thin film electrodes

The FTO conductive glass is ultrasonically cleaned and dried, then placed in a TiCl ₄ aqueous solution for treatment, and then placed on a heating table for calcination to form a TiO ₂ electron transmission layer, thereby obtaining a transparent conductive glass/electron transmission layer thin film electrode;

3) Preparation of transparent conductive glass/electron transmission layer/mesoporous layer/insulating scaffold layer thin film electrode

Spin-coat TiO ₂ slurry on the transparent conductive glass/electron transport layer thin film electrode prepared in step 2). After drying, place it on a heating table for low-temperature heat treatment, then naturally cool to room temperature, and then spin-coat ZrO ₂ slurry. After drying , placed on a heating table for calcination, and then naturally cooled to room temperature, thereby obtaining a transparent conductive glass/electron transmission layer/mesoporous layer/insulating scaffold layer thin film electrode;

4) Preparation of transparent conductive glass/electron transport layer/mesoporous layer/insulating scaffold layer/perovskite active layer thin film electrode

Place the transparent conductive glass/electron transport layer/mesoporous layer/insulating scaffold layer thin film electrode prepared in step 3) on the heating table and preheat it, then add dropwise mixed cationic perovskite (FA) _x (MA) _1-x PbI _3. The precursor liquid is placed on the heating table, heated and kept at temperature for crystallization, thereby obtaining transparent conductive glass/electron transmission layer/mesoporous layer/insulating scaffold layer/perovskite active layer thin film electrode;

5) Obtain perovskite solar cells

After scraping and coating conductive carbon slurry on the transparent conductive glass/electron transport layer/mesoporous layer/insulating scaffold layer/perovskite active layer thin film electrode prepared in step 4), solidify to prepare a carbon electrode, thereby obtaining a stable perovskite Solar battery.

As mentioned above, in the liquid phase preparation method, preferably, in step 1), the preparation process of the mixed cationic perovskite (FA) _x (MA) _{1- x} PbI ₃ precursor solution includes:

Put lead iodide and methylamine iodide into anhydrous N,N-dimethylformamide and use ultrasound to completely dissolve them to obtain a DMF solution of MAPbI ₃ ; put lead iodide and formamidine iodide into anhydrous In N,N-dimethylformamide, use ultrasound to completely dissolve it to obtain a DMF solution of FAPbI ₃ ;

Mix the DMF solution of MAPbI ₃ and the DMF solution of FAPbI ₃ according to a certain amount of substance to obtain a mixed cationic perovskite (FA) _x (MA) _1-x PbI ₃ precursor solution, where x is the amount of substance. , x is 0.05~0.45.

As mentioned above, in the liquid phase preparation method, preferably, in step 2), the FTO conductive glass is ultrasonically cleaned and dried, and then placed in a TiCl ₄ aqueous solution with a concentration of 0.03-0.10 mol/L at 50-80°C for 20-50 minutes. Then, after cleaning with deionized water and absolute ethanol, it is placed on a heating table at 400-500°C and calcined for 10-40 minutes to form a nano-TiO ₂ electron transmission layer, thereby obtaining a transparent conductive glass/electron transmission layer thin film electrode.

According to the liquid phase preparation method as mentioned above, preferably, in step 3), the TiO ₂ slurry is spin-coated on the transparent conductive glass/electron transport layer thin film electrode, and after drying, it is placed on a heating table at 150-250°C for heat treatment for 8-12 minutes Then, naturally cool to room temperature; then spin-coat the ZrO ₂ slurry. After drying, place it on a 450-600°C heating table for heat treatment for 25-35 minutes, and then naturally cool to room temperature to obtain transparent conductive glass/electron transmission layer/mesoporous Layer/Insulating Support Layer Thin Film Electrode.

According to the liquid phase preparation method as described above, preferably, in step 4), the prepared transparent conductive glass/electron transmission layer/mesoporous layer/insulating scaffold layer thin film electrode is placed on a heating table for preheating, and then mixed cationic calcium is added dropwise _{Spin - coat} titanite ( _{FA )} ) _1-x PbI ₃ precursor liquid crystallizes on the gaps and surfaces of the mesoporous layer and insulating scaffold layer, thereby obtaining a transparent conductive glass/electron transport layer/mesoporous layer/insulating scaffold layer/perovskite active layer thin film electrode.

The liquid phase preparation method as described above, preferably, in step 5),

After scraping the conductive carbon slurry on the transparent conductive glass/electron transport layer/mesoporous layer/insulating scaffold layer/perovskite active layer thin film electrode, it is cured at 90~110°C for 5~30 minutes to form a hydrophobic carbon electrode, thus obtaining Highly stable perovskite solar cells.

Compared with the closest existing technology, the technical solution provided by the present invention has the following beneficial effects:

(1) The perovskite solar cells provided by the present invention have high power conversion efficiency. The solar cells prepared under optimized conditions were tested for power conversion under AM1.5G standard sunlight (intensity: 100mW/cm ² ) in a solar simulator. The efficiency is as high as 9.5% or more.

(2) The perovskite solar cell provided by the present invention has the advantages of strong moisture resistance and high stability.

(3) The technical solution for preparing perovskite solar cells provided by the present invention is prepared by a liquid phase method under natural air conditions. It does not require a glove box or other special protective measures. It has the characteristics of simple process and easy operation.

(4) The perovskite solar cell prepared by the present invention does not contain an expensive hole transport layer, and does not involve the process of vacuum evaporation of noble metal electrodes, which greatly reduces the cost.

(5) The technical solution provided by the present invention uses carbon electrodes instead of metal electrodes when preparing perovskite solar cells. The carbon electrode is hydrophobic. When the perovskite solar cell works under natural conditions, it can improve the moisture resistance of the device and make it work stably for a long time. Specifically, it means: the active layer used in the present invention is HC(NH ₂ ) ₂ ⁺ , FA ⁺ ) and methylamine (CH ₃ NH ₃ ⁺ , MA ⁺ ) cations mixed perovskite (FA) _x (MA) _1-x PbI ₃ , using mixed cations to improve the material of the perovskite active layer Stability; the hydrophobic carbon electrode resists the erosion of solar cells by water vapor, further improving the stability of the device. The attenuation test in high-humidity air showed that the solar cell power conversion efficiency still maintained more than 90% of the initial value after 2 months, demonstrating long-term stability.

Description of drawings

Figure 1 is a structural diagram of a highly stable perovskite solar cell provided by the present invention;

Figure 2 is a J-V characteristic curve test chart of the perovskite solar cell prepared in Example 1 of the present invention;

Figure 3 is a test chart of the contact angle between the carbon electrode surface and water droplets of the perovskite solar cell prepared in Example 1 of the present invention;

Figure 4 is a stability test chart of the perovskite solar cell prepared in Example 1 of the present invention;

In the picture: 1. Transparent conductive glass; 11. Glass; 12. FTO layer; 3. Electron transport layer; 4. Mesoporous layer; 5. Insulating support layer; 6. Perovskite active layer; 7. Carbon electrode layer.

Detailed ways

The technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art fall within the scope of protection of the present invention.

The present invention will be described in detail below with reference to the accompanying drawings and embodiments. It should be noted that, as long as there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

The present invention provides a highly stable perovskite solar cell and a liquid phase preparation method thereof. The perovskite solar cell includes: transparent conductive glass 1, electron transport layer 3, mesoporous layer 4, insulating support layer 5, perovskite active layer 6 and carbon electrode layer 7; wherein, the perovskite active layer 6 is a hybrid Cationic perovskite.

The perovskite active layer 6 is prepared by a one-step spin coating method. The perovskite active layer 6 is a mixed cation perovskite (FA) _x (MA) _1-x PbI ₃ , where x is the substance. The quantity fraction, x is 0.05~0.45 (for example, 0.06, 0.08, 0.10, 0.13, 0.16, 0.19, 0.22, 0.25, 0.28, 0.31, 0.34, 0.37, 0.40, 0.42, 0.44).

Further preferably, the mixed cationic perovskite (FA) _x (MA) _1-x PbI ₃ is methylamine iodide (HC(NH ₂ ) ₂ I, FAI) and methylamine iodide (CH ₃ NH ₃ , MAI) prepared from raw materials.

In a specific embodiment of the present invention, the perovskite active layer 6 is penetrated and filled into the mesoporous layer 4 and the insulating support layer 5 and covers the surface of the insulating support layer 5 .

In a specific embodiment of the present invention, the transparent conductive glass 1 is fluorine-doped tin dioxide (FTO) conductive glass, that is, the FTO conductive glass has an FTO layer 12 on the top of the glass 11, which is then called FTO conductive glass; Electronics The transmission layer 3 is a nano TiO ₂ layer; the mesoporous layer 4 is a mesoporous TiO ₂ layer; the insulating support layer 5 is a porous ZrO ₂ layer; the carbon electrode layer 7 is a hydrophobic carbon electrode.

Further preferably, the thickness of the electron transport layer 3 is 10 to 40nm (for example, 12nm, 14nm, 16nm, 8nm, 20nm, 22nm, 24nm, 26nm, 8nm, 30nm, 32nm, 34nm, 36nm, 8nm, 39nm); the mesoporous layer The thickness of 4 is 150~300nm (such as 152nm, 157nm, 160nm, 165nm, 170nm, 175nm, 80nm, 185nm, 190nm, 195nm, 200nm, 205nm, 210nm, 215nm, 220nm, 225nm, 230nm, 235nm, 2 40nm, 248nm, 256nm , 262nm, 268nm, 275nm, 283nm, 290nm, 295nm, 298nm); the thickness of the insulating support layer 5 is 150~300nm (such as 152nm, 157nm, 160nm, 165nm, 170nm, 175nm, 80nm, 185nm, 190nm, 195nm, 20 0nm, 205nm, 210nm, 215nm, 220nm, 225nm, 230nm, 235nm, 240nm, 248nm, 256nm, 262nm, 268nm, 275nm, 283nm, 290nm, 295nm, 298nm); the thickness of the carbon electrode layer 7 is 8 to 20 μm (for example, 9 μm, 1 0μm , 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm); the thickness of the perovskite active layer 6 is 300~700nm (such as 330nm, 370nm, 400nm, 450nm, 490nm, 530nm, 570nm, 610nm, 650nm, 690nm).

Preferably, the thickness of the insulating support layer 5 is 200 to 300nm (for example, 210nm, 220nm, 230nm, 240nm, 250nm, 260nm, 270nm, 280nm, 290nm).

In order to explain more clearly the structural composition of perovskite solar cells in specific embodiments of the present invention, the present invention also provides a liquid phase preparation method of perovskite solar cells. The liquid phase preparation method is adopted in a natural air atmosphere. The liquid phase method of spin coating and blade coating completes all preparation processes. The liquid phase preparation method includes the following steps:

1) Preparation of mixed cationic perovskite precursor liquid

Prepare mixed cationic perovskite (FA) _x (MA) _1-x PbI ₃ precursor solution according to a certain amount of substances for later use;

2) Preparation of transparent conductive glass/electron transport layer thin film electrodes

The FTO conductive glass is ultrasonically cleaned and dried, then placed in a TiCl ₄ aqueous solution for treatment, and then placed on a heating table for calcination to form a TiO ₂ electron transmission layer, thereby obtaining a transparent conductive glass/electron transmission layer thin film electrode;

3) Preparation of transparent conductive glass/electron transmission layer/mesoporous layer/insulating scaffold layer thin film electrode

Spin-coat TiO ₂ slurry on the transparent conductive glass/electron transport layer thin film electrode prepared in step 2). After drying, place it on a heating table for low-temperature heat treatment and naturally cool to room temperature. Then spin-coat ZrO ₂ slurry and dry it. , placed on a heating table for thermal calcination, and then naturally cooled to room temperature, thereby obtaining a transparent conductive glass/electron transmission layer/mesoporous layer/insulating scaffold layer thin film electrode;

4) Preparation of transparent conductive glass/electron transport layer/mesoporous layer/insulating scaffold layer/perovskite active layer thin film electrode

Place the transparent conductive glass/electron transport layer/mesoporous layer/insulating scaffold layer thin film electrode prepared in step 3) on the heating table and preheat it, then add dropwise the mixed cationic perovskite (FA) _x (MA) _1-x PbI _3. The precursor liquid is placed on the heating table, heated and kept at temperature for crystallization, thereby obtaining transparent conductive glass/electron transmission layer/mesoporous layer/insulating scaffold layer/perovskite active layer thin film electrode;

5) Obtain perovskite solar cells

After scraping and coating conductive carbon slurry on the transparent conductive glass/electron transport layer/mesoporous layer/insulating scaffold layer/perovskite active layer thin film electrode prepared in step 4), solidify to prepare a carbon electrode, thereby obtaining a stable perovskite Solar battery.

In specific embodiments of the present invention, in step 1), the preparation process of the mixed cationic perovskite (FA) _x (MA) _1-x PbI ₃ precursor solution includes:

Put lead iodide (PbI ₂ ) and methylamine iodide (AMI) with a molar ratio of 1:1 into anhydrous N,N-dimethylformamide (DMF) and sonicate to completely dissolve them to obtain MAPbI ₃ DMF solution; put lead iodide (PbI ₂ ) and formamidine iodide (FMI) with a molar ratio of 1:1 into anhydrous N,N-dimethylformamide (DMF), and sonicate to completely dissolve , obtain the DMF solution of FAPbI ₃ ;

Mix the DMF solution of MAPbI ₃ and the DMF solution of FAPbI ₃ according to a certain amount of substance to obtain a mixed cationic perovskite (FA) _x (MA) _1-x PbI ₃ precursor solution, where x is the amount of substance. , x is 0.05~0.45 (for example, 0.06, 0.08, 0.10, 0.13, 0.16, 0.19, 0.22, 0.25, 0.28, 0.31, 0.34, 0.37, 0.40, 0.42, 0.44).

In a specific embodiment of the present invention, in step 2), the FTO conductive glass is ultrasonically cleaned and dried, and then placed in a concentration of 0.03 to 0.10 mol/L (for example, 0.035 mol/L, 0.04 mol/L, 0.045 mol/L). L, 0.05mol/L, 0.055mol/L, 0.06mol/L, 0.065mol/L, 0.07mol/L, 0.075mol/L, 0.08mol/L, 0.085mol/L, 0.09mol/L, 0.095mol/ L) TiCl ₄ aqueous solution at 50~80℃ (such as 53℃, 55℃, 58℃, 60℃, 62℃, 65℃, 68℃, 70℃, 73℃, 75℃, 78℃) for 20~50min ( For example, 22min, 25min, 28min, 30min, 32min, 35min, 38min, 40min, 42min, 45min, 48min), and then rinsed with deionized water and absolute ethanol respectively, and then placed at 400~500℃ (for example, 410℃, 420℃, 430℃, 440℃, 450℃, 460℃, 470℃, 480℃, 485℃, 490℃, 495℃) Calcining on the heating table for 10~40min (such as 12min, 15min, 18min, 20min, 22min, 25min , 28min, 30min, 32min, 35min, 38min) to form a nano- _TiO2 electron transmission layer, thereby obtaining a transparent conductive glass/electron transmission layer thin film electrode;

Preferably, the FTO conductive glass is ultrasonically cleaned with tap water containing detergent, distilled water, acetone and ethanol in sequence and then blown dry.

In a specific embodiment of the present invention, in step 3), TiO ₂ slurry is spin-coated on the transparent conductive glass/electron transport layer thin film electrode, and after drying, it is placed at 150 to 250°C (for example, 155°C, 160°C, 165°C ℃, 170℃, 175℃, 180℃, 185℃, 190℃, 195℃, 200℃, 205℃, 210℃, 215℃, 220℃, 225℃, 230℃, 235℃, 240℃) heating table After heat treatment for 8 to 12 minutes (such as 9min, 9.2min, 9.5min, 9.8min, 10min, 10.2min, 10.5min, 10.8min, 11min, 11.2min, 11.5min, 11.8min), naturally cool to room temperature; then spin-coat ZrO _2. After drying the slurry, place it on a heating table at 450~600℃ (such as 470℃, 490℃, 510℃, 530℃, 550℃, 570℃, 590℃) for heat treatment for 25~35min (such as 26min, 27min, 28min , 29min, 30min, 31min, 32min, 33min, 34min), then naturally cool to room temperature, thereby obtaining a transparent conductive glass/electron transmission layer/mesoporous layer/insulating scaffold layer thin film electrode.

Preferably, the rotation speed of the spin coating TiO ₂ slurry and the spin coating ZrO ₂ slurry is 3500 to 4500 rpm (for example, 3600 rpm, 3700 rpm, 3800 rpm, 3900 rpm, 4000 rpm, 4100 rpm, 4200 rpm, 4300 rpm, 4400 rpm), and the spin coating time is 25 ~35s (such as 26s, 27s, 28s, 29s, 30s, 31s, 32s, 33s, 34s).

In specific embodiments of the present invention, the mesoporous structure cannot be formed directly after spin-coating the TiO ₂ slurry in step 3). This is because low-temperature heat treatment is used when spin-coating the TiO ₂ slurry. Low-temperature heat treatment Organic matter such as binders cannot be completely removed, and the mesoporous structure has not yet been formed. It is necessary to spin _- coat the TiO slurry and perform low-temperature heat treatment before spin-coating the ZrO slurry and perform high-temperature heat treatment, so that _{the TiO 2 mesoporous} structure and the ZrO ₂ structure (insulating scaffold layer mesoporous) can be obtained at the same time.

In a specific embodiment of the present invention, in step 4), after placing the prepared transparent conductive glass/electron transport layer/mesoporous layer/insulating scaffold layer thin film electrode on a heating table for preheating, the mixed cationic perovskite is added dropwise (FA) _x (MA) _1-x PbI ₃ precursor solution spin coating, that is, (FA) _x (MA) ₁ using N,N-dimethylformamide (DMF) as the solvent is spin-coated on the insulating support layer _-x PbI ₃ precursor solution; after spin coating, place it on a heating table at 80~110℃ (such as 82℃, 85℃, 90℃, 92℃, 95℃, 98℃, 100℃, 102℃, 105℃, 108℃) on, heat and keep crystallized for 10 to 70 minutes (for example, 12min, 15min, 20min, 25min, 30min, 35min, 40min, 45min, 50min, 55min, 60min, 65min, 68min). The solute is in the gaps between the mesoporous layer and the insulating scaffold layer. and crystallize on the surface, thereby obtaining transparent conductive glass/electron transport layer/mesoporous layer/insulating scaffold layer/perovskite active layer thin film electrode.

Preferably, the transparent conductive glass/electron transmission layer/mesoporous layer/insulating scaffold layer thin film electrode is placed on the heating table for a preheating time of 7 to 15 minutes (for example, 8 minutes, 9 minutes, 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes). The temperature _of the mixed cationic _perovskite ( _FA ) , 61℃, 64℃, 66℃, 69℃, 71℃, 73℃, 74℃);

Preferably, when the _mixed cationic _perovskite ( _FA ) , 1860rpm, 1880rpm, 1890rpm) spin coating for 2 to 4s (such as 2s, 2.2s, 2.4s, 2.5s, 2.7s, 2.9s, 3.0s, 3.2s, 3.5s, 3.8s, 3.9s, 4.0s), Then spin coating at a rotation speed of 3500 to 3800rpm (such as 3510rpm, 3550rpm, 3580rpm, 3600rpm, 3630rpm, 3660rpm, 3690rpm, 3730rpm, 3760rpm, 3780rpm, 3790rpm) for 25 to 35s (such as 26s, 27s, 28s, 29s, 30s) ,31s ,32s,33s,34s).

In a specific embodiment of the present invention, in step 5), after scraping conductive carbon slurry on the transparent conductive glass/electron transmission layer/mesoporous layer/insulating support layer/perovskite active layer thin film electrode, the temperature is 90 to 110 ℃ (such as 91℃, 93℃, 95℃, 97℃, 99℃, 101℃, 103℃, 105℃, 107℃, 109℃) curing 5~30min (such as 6min, 8min, 10min, 12min, 14min, 16min , 18min, 20min, 22min, 25min, 28min, 29min) to form a hydrophobic carbon electrode, thereby obtaining a highly stable perovskite solar cell.

The device structure of the highly stable perovskite solar cell provided by the present invention does not use a hole transport layer or a noble metal electrode. This perovskite solar cell uses a hydrophobic carbon electrode as the counter electrode to improve the moisture resistance of the device.

In summary, the present invention provides a highly stable perovskite solar cell and a simple preparation method thereof. The solar cell is composed of transparent conductive glass, electron transmission layer, mesoporous layer, insulating support layer, perovskite active layer and carbon electrode layer. The preparation process does not require a glove box and is carried out in a natural air atmosphere. The active layer is a perovskite (FA) x (MA) 1 _{-x PbI 3} mixed with formazan (HC(NH ₂ ) ₂ ⁺ , FA ⁺ ) and methylamine (CH ₃ NH ₃ ⁺ , MA ⁺ ) cations. The use of mixed cations improves the material stability of the perovskite active layer; the hydrophobic carbon electrode resists the erosion of solar cells by water vapor, further improving the stability of the device. The attenuation test in high-humidity air showed that the solar cell power conversion efficiency still maintained more than 90% of the initial value after 2 months, demonstrating long-term stability. The device structure abandons the high-cost hole transport layer and precious metal electrodes and uses low-temperature cured carbon electrodes, which greatly simplifies the preparation process and saves costs, making perovskite solar cells easy to mass-produce and apply.

Example 1

Under natural air conditions, a simple liquid phase method is used to prepare highly stable perovskite solar cells. The specific steps are as follows:

(1) Weigh 0.9353g of lead iodide (PbI ₂ ) and 0.3228g of methylamine iodide (AMI) into 2mL of anhydrous N,N-dimethylformamide (DMF), and sonicate until completely Dissolve to obtain a DMF solution of MAPbI ₃ ; weigh 0.9167 PbI ₂ and 0.3420g formamidine iodide (FMI) into 2 mL of anhydrous DMF, and sonicate to completely dissolve them to obtain a DMF solution of FAPbI ₃ . Mix the above two perovskite solutions at x=0.3 to obtain a mixed cationic perovskite (FA) _0.3 (MA) _0.7 PbI ₃ precursor solution for later use.

(2) Ultrasonically clean the FTO conductive glass with tap water containing detergent, distilled water, acetone and ethanol in sequence, and blow dry. Then put the above-mentioned substrate into a TiCl ₄ aqueous solution with a concentration of 0.08mol/L, incubate it at 70°C for 40 minutes, take it out, rinse it with distilled water and ethanol respectively, blow dry, place it on a heating table, and heat to 450°C. After heat treatment for 30 minutes, nano-TiO ₂ forms an electron transport layer.

(3) Spin-coat nano-TiO ₂ slurry on the above substrate, the rotation speed is 3800 rpm, the spin-coating time is 30 s, then heat treat at 200°C for 10 minutes on the heating table, naturally cool to room temperature, then spin-coat nano-ZrO ₂ slurry, and rotate The speed is 4200 rpm, the spin coating time is 30 s, and finally it is placed on the heating table and heated to 500°C, heat treated for 30 min, and naturally cooled to room temperature to form a mesoporous TiO ₂ layer and a porous ZrO ₂ insulating scaffold layer.

(4) After the above substrate is preheated on the heating table for 10 minutes, dropwise add mixed cationic perovskite (FA) _0.3 (MA) _0.7 PbI ₃ precursor solution at 50°C for spin coating, and spin coating at a rate of 1800 rpm for 3 s. Spin coating at a speed of 3600 rpm for 30 seconds, then place the substrate on a heating table at 100°C and heat for 50 minutes to volatilize the solvent. The solute crystallizes in the gaps and surfaces of the mesoporous TiO ₂ layer and the porous ZrO ₂ insulating scaffold layer to form calcium Titanium active layer.

(5) Finally, the conductive carbon slurry is scraped onto the above substrate, cured at 100°C for 15 minutes to form a carbon electrode, and allowed to cool naturally to obtain a highly stable perovskite solar cell as shown in Figure 1.

The perovskite solar cell prepared in this example was tested for the current density-voltage (JV) characteristic curve under AM1.5G standard sunlight (intensity: 100mW/cm ² ) in a solar simulator. The test results are shown in Figure 2 . The solar cell achieved a short-circuit current density ( _Jsc ) of 21.58mA/ ^cm2 , an open-circuit voltage (V _°C ) of 0.982V, a fill factor (FF) of 0.452, and a power conversion efficiency (PCE) of 9.58%.

Water droplets were added to the surface of the carbon electrode of the perovskite solar cell prepared in this example to test the contact angle, and the results are shown in Figure 3 (the picture when water droplets were added to the surface of the carbon electrode of the solar cell for testing is a black and white photo, Other black and white line drawings do not show the effect of this test, so the black and white photo graphics are provided here). The results show that water forms a spherical shape on the surface of the carbon electrode. The shape of the water droplets remains unchanged over time and is stable. The contact angle between the carbon electrode and water is 123°, indicating that the carbon electrode is highly hydrophobic and water cannot penetrate the carbon electrode. layer, which well protects the perovskite active layer.

The perovskite solar cells prepared in this example were stored under natural conditions without taking any protective measures. Every one week, they were exposed to AM1.5G standard sunlight (intensity: 100mW/cm ² ) in a solar simulator. The JV characteristic curve was tested below to evaluate the change of power conversion efficiency with time. The results are shown in Figure 4. The results show that when the solar cell is stored under natural conditions, the power conversion efficiency slowly decays over time, but the decay rate is particularly slow. After 2 months, the power conversion efficiency still maintains more than 90% of the initial value, verifying Perovskite solar cells prepared by this simple method have high stability.

Example 2

Under natural air conditions, a simple liquid phase method is used to prepare highly stable perovskite solar cells. The specific steps are as follows:

(1) Weigh 0.9353g of PbI ₂ and 0.3228g of AMI into 2 mL of anhydrous DMF, and dissolve them completely by ultrasonic to obtain the perovskite MAPbI ₃ precursor solution for later use.

(2) Ultrasonically clean the FTO conductive glass with tap water containing detergent, distilled water, acetone and ethanol in sequence, and blow dry. Then put the above-mentioned substrate into a TiCl ₄ aqueous solution with a concentration of 0.08mol/L, incubate it at 70°C for 40 minutes, take it out, rinse it with distilled water and ethanol respectively, blow dry, place it on a heating table, and heat to 450°C. After heat treatment for 30 minutes, nano-TiO ₂ forms an electron transport layer.

(3) Spin-coat nano-TiO ₂ slurry on the above substrate, the rotation speed is 3800 rpm, the spin-coating time is 30 s, then heat treat at 200°C for 10 minutes on the heating table, naturally cool to room temperature, then spin-coat nano-ZrO ₂ slurry, and rotate The speed is 4200 rpm, the spin coating time is 30 s, and finally it is placed on the heating table and heated to 500°C, heat treated for 30 min, and naturally cooled to room temperature to form a mesoporous TiO ₂ layer and a porous ZrO ₂ insulating scaffold layer.

(4) After the above substrate is preheated on the heating table for 10 minutes, the perovskite MAPbI ₃ precursor solution at 50°C is added dropwise and spin-coated at a speed of 1800 rpm for 3 s, then spin-coated at a speed of 3600 rpm for 30 s, and then the substrate is spin-coated. The sheet is placed on a heating table at 100°C and heated for 40 minutes to volatilize the solvent. The solute crystallizes in the gaps and surfaces of the mesoporous TiO ₂ layer and the porous ZrO ₂ insulating scaffold layer to form a perovskite active layer.

(5) Finally, conductive carbon slurry is scraped onto the above substrate, cured at 100°C for 15 minutes to form a carbon electrode, and allowed to cool naturally to obtain a highly stable perovskite solar cell.

The perovskite solar cell prepared in this example was tested for the JV characteristic curve under AM1.5G standard sunlight (intensity 100mW/cm ² ) in a solar simulator. The short-circuit current density of the solar cell was 18.92mA/cm. ² , the open circuit voltage is 0.928V, the fill factor is 0.453, and the power conversion efficiency is 7.95%; other performance tests are the same as Example 1.

Example 3

Under natural air conditions, a simple liquid phase method is used to prepare highly stable perovskite solar cells. The specific steps are as follows:

(1) Weigh 0.9353g of lead iodide (PbI ₂ ) and 0.3228g of methylamine iodide (AMI) into 2mL of anhydrous N,N-dimethylformamide (DMF), and sonicate until completely Dissolve to obtain a DMF solution of MAPbI ₃ ; weigh 0.9167 PbI ₂ and 0.3420g formamidine iodide (FMI) into 2 mL of anhydrous DMF, and sonicate to completely dissolve them to obtain a DMF solution of FAPbI ₃ . Mix the above two perovskite solutions at x=0.1 to obtain a mixed cationic perovskite (FA) _0.1 (MA) _0.9 PbI ₃ precursor solution for later use.

(2) Ultrasonically clean the FTO conductive glass with tap water containing detergent, distilled water, acetone and ethanol in sequence, and blow dry. Then put the above-mentioned substrate into a TiCl ₄ aqueous solution with a concentration of 0.08mol/L, incubate it at 70°C for 40 minutes, take it out, rinse it with distilled water and ethanol respectively, blow dry, place it on a heating table, and heat to 450°C. After heat treatment for 30 minutes, nano-TiO ₂ forms an electron transport layer.

(3) The substrate was spin-coated with nano- _TiO2 slurry at a rotation rate of 3800 rpm for 30 s, then heat-treated at 200°C on a heating table for 10 min, naturally cooled to room temperature, and then spin-coated with nano- _ZrO2 slurry at a rotation rate of 4200 rpm for 30 s. Finally, the substrate was placed on a heating table and heated to 500°C, heat-treated for 30 min, and naturally cooled to room temperature to form a mesoporous _TiO2 layer and a porous _ZrO2 insulating support layer.

(4) After the above substrate is preheated on the heating table for 10 minutes, dropwise add mixed cationic perovskite (FA) _0.1 (MA) _0.9 PbI ₃ precursor solution at 50°C for spin coating, and spin coating at a rate of 1800 rpm for 3 s. Spin coating at a speed of 3600 rpm for 30 seconds, then place the substrate on a heating table at 100°C and heat for 50 minutes to volatilize the solvent. The solute crystallizes in the gaps and surfaces of the mesoporous TiO ₂ layer and the porous ZrO ₂ insulating scaffold layer to form calcium Titanium active layer.

(5) Finally, conductive carbon slurry is scraped onto the above substrate, cured at 100°C for 15 minutes to form a carbon electrode, and allowed to cool naturally to obtain a highly stable perovskite solar cell.

The perovskite solar cell prepared in this example was tested for the JV characteristic curve under AM1.5G standard sunlight (intensity 100mW/cm ² ) in a solar simulator. The short-circuit current density of the solar cell was 17.32mA/cm. ² , the open circuit voltage is 0.910V, the fill factor is 0.452, and the power conversion efficiency is 7.12%; other performance tests are the same as Example 1.

Example 4

Under natural air conditions, a simple liquid phase method is used to prepare highly stable perovskite solar cells. The specific steps are as follows:

(1) Weigh 0.9353g of lead iodide (PbI ₂ ) and 0.3228g of methylamine iodide (AMI) into 2mL of anhydrous N,N-dimethylformamide (DMF), and sonicate until completely Dissolve to obtain a DMF solution of MAPbI ₃ ; weigh 0.9167 PbI ₂ and 0.3420g formamidine iodide (FMI) into 2 mL of anhydrous DMF, and sonicate to completely dissolve them to obtain a DMF solution of FAPbI ₃ . Mix the above two perovskite solutions at x=0.2 to obtain a mixed cationic perovskite (FA) _0.2 (MA) _0.8 PbI ₃ precursor solution for later use.

(2) Ultrasonically clean the FTO conductive glass with tap water containing detergent, distilled water, acetone and ethanol in sequence, and blow dry. Then put the above-mentioned substrate into a TiCl ₄ aqueous solution with a concentration of 0.08mol/L, incubate it at 70°C for 40 minutes, take it out, rinse it with distilled water and ethanol respectively, blow dry, place it on a heating table, and heat to 450°C. After heat treatment for 30 minutes, nano-TiO ₂ forms an electron transport layer.

(3) Spin-coat nano-TiO ₂ slurry on the above substrate, the rotation speed is 3800 rpm, the spin-coating time is 30 s, then heat treat at 200°C for 10 minutes on the heating table, naturally cool to room temperature, then spin-coat nano-ZrO ₂ slurry, and rotate The speed is 4200 rpm, the spin coating time is 30 s, and finally it is placed on the heating table and heated to 500°C, heat treated for 30 min, and naturally cooled to room temperature to form a mesoporous TiO ₂ layer and a porous ZrO ₂ insulating scaffold layer.

(4) After preheating the above substrate on the heating table for 10 minutes, dropwise add mixed cationic perovskite (FA) _0.2 (MA) _0.8 PbI ₃ precursor solution at 50°C for spin coating, and spin coating at a rate of 1800 rpm for 3 s. Spin coating at a speed of 3600 rpm for 30 seconds, then place the substrate on a heating table at 100°C and heat for 50 minutes to volatilize the solvent. The solute crystallizes in the gaps and surfaces of the mesoporous TiO ₂ layer and the porous ZrO ₂ insulating scaffold layer to form calcium Titanium active layer.

(5) Finally, conductive carbon slurry is scraped onto the above substrate, cured at 100°C for 15 minutes to form a carbon electrode, and allowed to cool naturally to obtain a highly stable perovskite solar cell.

The perovskite solar cell prepared in this example was tested for the JV characteristic curve under AM1.5G standard sunlight (intensity: 100mW/cm ² ) in a solar simulator. The short-circuit current density of the solar cell was 19.92mA/cm. ² , the open circuit voltage is 0.933V, the fill factor is 0.462, and the power conversion efficiency is 8.59%; other performance tests are the same as Example 1.

Example 5

Under natural air conditions, a simple liquid phase method is used to prepare highly stable perovskite solar cells. The specific steps are as follows:

(1) Weigh 0.9353g of lead iodide (PbI ₂ ) and 0.3228g of methylamine iodide (AMI) into 2mL of anhydrous N,N-dimethylformamide (DMF), and sonicate until completely Dissolve to obtain a DMF solution of MAPbI ₃ ; weigh 0.9167 PbI ₂ and 0.3420g formamidine iodide (FMI) into 2 mL of anhydrous DMF, and sonicate to completely dissolve them to obtain a DMF solution of FAPbI ₃ . Mix the above two perovskite solutions at x=0.4 to obtain a mixed cationic perovskite (FA) _0.4 (MA) _0.6 PbI ₃ precursor solution for later use.

(2) Ultrasonically clean the FTO conductive glass with tap water containing detergent, distilled water, acetone and ethanol in sequence, and blow dry. Then put the above-mentioned substrate into a TiCl ₄ aqueous solution with a concentration of 0.08mol/L, incubate it at 70°C for 40 minutes, take it out, rinse it with distilled water and ethanol respectively, blow dry, place it on a heating table, and heat to 450°C. After heat treatment for 30 minutes, nano-TiO ₂ forms an electron transport layer.

(3) Spin-coat nano-TiO ₂ slurry on the above substrate, the rotation speed is 3800 rpm, the spin-coating time is 30 s, then heat treat at 200°C for 10 minutes on the heating table, naturally cool to room temperature, then spin-coat nano-ZrO ₂ slurry, and rotate The speed is 4200 rpm, the spin coating time is 30 s, and finally it is placed on the heating table and heated to 500°C, heat treated for 30 min, and naturally cooled to room temperature to form a mesoporous TiO ₂ layer and a porous ZrO ₂ insulating scaffold layer.

(4) After the above substrate is preheated on the heating table for 10 minutes, dropwise add mixed cationic perovskite (FA) _0.4 (MA) _0.6 PbI ₃ precursor solution at 50°C and spin-coat at a rate of 1800 rpm for 3 s. Spin coating at a speed of 3600 rpm for 30 seconds, then place the substrate on a heating table at 100°C and heat for 50 minutes to volatilize the solvent. The solute crystallizes in the gaps and surfaces of the mesoporous TiO ₂ layer and the porous ZrO ₂ insulating scaffold layer to form calcium Titanium active layer.

(5) Finally, conductive carbon slurry is scraped onto the above substrate, cured at 100°C for 15 minutes to form a carbon electrode, and allowed to cool naturally to obtain a highly stable perovskite solar cell.

The JV characteristic curve of the perovskite solar cell prepared in this example was tested under AM1.5G standard sunlight (intensity 100mW/cm ² ) in a solar simulator. The short-circuit current density of the solar cell was 19.65mA/cm. ² , the open circuit voltage is 0.912V, the fill factor is 0.454, and the power conversion efficiency is 8.14%; other performance tests are the same as Example 1.

Comparative ratio

(1) Ultrasonically clean the FTO conductive glass with tap water containing detergent, distilled water, acetone and ethanol in sequence, and blow dry. Then put the above substrate into a TiCl ₄ aqueous solution with a concentration of 0.08mol/L, incubate it at 70°C for 40 minutes, take it out, rinse it with distilled water and ethanol, blow dry, and place it on a heating table for heat treatment at 450°C for 30 minutes. Nano- _TiO2 forms the electron transport layer.

(2) Spin-coat the nano-TiO ₂ slurry on the above-mentioned substrate, with a rotation speed of 3800 rpm and a spin-coating time of 30 seconds. Then, heat to 200°C and keep for 10 minutes on the heating table, continue to heat to 500°C and keep for 30 minutes, and naturally cool to room temperature. A mesoporous _TiO2 layer is formed.

(3) Weigh 0.9353g of lead iodide (PbI ₂ ) and 0.3228g of methylamine iodide (AMI) into 2 mL of anhydrous N,N-dimethylformamide (DMF), and sonicate until completely Dissolve to obtain a DMF solution of MAPbI ₃ ; weigh 0.9167 PbI ₂ and 0.3420g formamidine iodide (FMI) into 2 mL of anhydrous DMF, and sonicate to completely dissolve them to obtain a DMF solution of FAPbI ₃ . Mix the above two perovskite solutions at x=0.3 to obtain a mixed cationic perovskite (FA) _0.3 (MA) _0.7 PbI ₃ precursor solution for later use.

(4) 1mL of spiro-OMeTAD (2,2',7,7'-tetrakis[N,N-bis(4-methoxyphenyl)amino]-9,9'-spiro with a concentration of 72.3mg/mL Difluorene) in chlorobenzene, 19 μL of an acetonitrile solution of lithium bistrifluoromethanesulfonyl imide with a concentration of 520 mg/mL, and 29 μL of 4-tert-butylpyridine were mixed evenly to obtain a hole transfer material precursor solution, which was set aside.

(5) The substrate prepared in the above step (2) is placed on the heating table, heated to 300°C, and kept warm for 10 minutes. After the remaining adsorbed water is driven off, it is moved to a glue homogenizer and spin-coated with mixed perovskite (FA) at 50°C. ) _0.3 (MA) _0.7 PbI ₃ precursor solution, spin coating at a rate of 1800 rpm for 3 seconds, then spin coating at a rate of 3600 rpm for 30 seconds, then place the substrate on a heating stage at 100°C and heat for 40 minutes to evaporate the solvent and remove the solute. The mesoporous TiO ₂ layer crystallizes in the voids and on the surface to form a perovskite active layer.

(6) Drop the hole transport material precursor liquid on the above substrate, with a rotation speed of 4000 rpm and a spin coating time of 20 s to form a hole transport layer.

The above steps (3) to (6) are performed in a glove box, the atmosphere of the glove box is high-purity nitrogen, and the H ₂ O vapor content is controlled below 0.01%.

(7) The above substrate is fixed in the coating chamber of the vacuum coating machine, evacuated until the pressure in the coating chamber reaches 4×10 ^{- 4} Pa, and gold is evaporated to a thickness of 80nm to obtain a perovskite thin film solar cell.

The perovskite solar cell prepared in this comparative example was tested for its JV characteristic curve under AM1.5G standard sunlight (intensity: 100 mW/cm ² ) irradiation on a solar simulator. The solar cell has a short-circuit current density of 21.89mA/cm ² , an open-circuit voltage of 1.015V, a fill factor of 0.726, and a power conversion efficiency of 16.13%. However, the solar cell was particularly unstable. When placed in a natural air bar for 7 days, the power conversion efficiency dropped to 11.56%, and the attenuation amplitude was 28.3% of the initial value. After 14 days, the power conversion efficiency dropped to 3.72%, and the attenuation amplitude was 28.3% of the initial value. 76.9% of the value; after 21, the current is basically undetectable and the device is scrapped.

The solar cell prepared in this comparative example consists of FTO conductive glass, _TiO2 dense layer, _TiO2 mesoporous layer, mixed cation perovskite layer, Spiro-MeOTAD based hole transport layer and gold counter electrode layer. Currently, Spiro-MeOTAD is relatively expensive, with 1 gram costing 1,800 yuan. Adding additives and solvents, the price of a solution containing 1 gram of Spiro-MeOTAD reaches 2,400 yuan. The preparation of precious metal counter electrodes requires a vacuum evaporation process, which has harsh conditions and complex operations. Although the power conversion efficiency of the perovskite solar cell prepared in this comparative example is relatively high, the preparation operation is complex and the cost is high, and the obtained solar cell has poor stability and low use value, and cannot be promoted for use.

In summary, by comparing Examples 1 to 5 and Comparative Examples, it can be seen that the perovskite solar cell prepared by the technical solution provided by the present invention has low cost, high power conversion efficiency, strong stability, and a cheap preparation method. The solar cell of the invention is composed of transparent conductive glass, electron transmission layer, mesoporous layer, insulating support layer, perovskite active layer and carbon electrode layer. Expensive hole transport layers and precious metal electrodes were abandoned from the high-efficiency perovskite solar cell structure, and inexpensive hydrophobic carbon electrodes were used. Under natural air conditions, solar cell devices are prepared using simple liquid phase methods such as spin coating and blade coating. The perovskite solar cells prepared by this method have the characteristics of high power conversion efficiency, long-term stability under natural air conditions, simple preparation process and low manufacturing cost, and can meet the requirements of large-scale industrial production.

To sum up, the present invention also has the following technical effects:

(1) The perovskite solar cells provided by the present invention have high power conversion efficiency. The solar cells prepared under optimized conditions were tested for power conversion under AM1.5G standard sunlight (intensity: 100mW/cm ² ) in a solar simulator. The efficiency is as high as 9.5% or more.

(2) The perovskite solar cell provided by the present invention has the advantages of strong moisture resistance and high stability.

(3) The technical solution for preparing perovskite solar cells provided by the present invention is prepared by a liquid phase method under natural air conditions. It does not require a glove box or other special protective measures. It has the characteristics of simple process and easy operation.

(4) The perovskite solar cell prepared by the present invention does not contain an expensive hole transport layer, and does not involve the process of vacuum evaporation of noble metal electrodes, which greatly reduces the cost.

(5) The technical solution provided by the present invention uses carbon electrodes instead of metal electrodes when preparing perovskite solar cells. The carbon electrode is hydrophobic. When the perovskite solar cell works under natural conditions, it can improve the moisture resistance of the device and make it work stably for a long time. Specifically, it means: the active layer used in the present invention is HC(NH ₂ ) ₂ ⁺ , FA ⁺ ) and methylamine (CH ₃ NH ₃ ⁺ , MA ⁺ ) cations mixed perovskite (FA) _x (MA) _1-x PbI ₃ , using mixed cations to improve the material of the perovskite active layer Stability; the hydrophobic carbon electrode resists the erosion of solar cells by water vapor, further improving the stability of the device. The attenuation test in high-humidity air showed that the solar cell power conversion efficiency still maintained more than 90% of the initial value after 2 months, demonstrating long-term stability.

The above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are within the scope of the pending rights of the present invention. within the scope of protection required.

Claims (2)

1. A liquid phase preparation method for perovskite solar cells, characterized in that the perovskite solar cells include: transparent conductive glass, electron transport layer, mesoporous layer, insulating support layer, perovskite active layer and carbon electrode layer; The perovskite active layer is a mixed cation perovskite; The liquid phase preparation method is to use the liquid phase method of spin coating and blade coating to complete all preparation processes in a natural air atmosphere; the liquid phase preparation method includes the following steps: 1) Preparation of mixed cationic perovskite precursor liquid Prepare a mixed cationic perovskite (FA) _x (MA) _1-x PbI ₃ precursor solution according to a certain amount of material and set aside for later use, where x is the amount of material and x is 0.3; the cation is formamidine cation. and methylamine cation; 2) Preparation of transparent conductive glass/electron transport layer thin film electrodes After ultrasonic cleaning and drying, the FTO conductive glass is placed in a 0.08mol/L TiCl ₄ aqueous solution at 70°C for 40 minutes, and then placed on a heating table for calcination to form a TiO ₂ electron transmission layer, thereby obtaining a transparent conductive glass/electron transmission layer Thin film electrode; the calcination is performed on a heating table at 450°C for 30 minutes; 3) Preparation of transparent conductive glass/electron transmission layer/mesoporous layer/insulating scaffold layer thin film electrode Spin-coat TiO ₂ slurry on the transparent conductive glass/electron transport layer thin film electrode prepared in step 2) at 3800 rpm for 30 s. After drying, place it on a heating table for low-temperature heat treatment, and then naturally cool to room temperature. The low-temperature heat treatment is Process at 200°C for 10 minutes; then spin-coat the ZrO ₂ slurry at 4200 rpm for 30 seconds. After drying, place it on a heating table and calcine at 500°C for 30 minutes, then naturally cool to room temperature to obtain a transparent conductive glass/electron transmission layer/medium Porous layer/insulating support layer thin film electrode; the thickness of the mesoporous layer is 150~300nm, and the thickness of the insulating support layer is 150~300nm; 4) Preparation of transparent conductive glass/electron transport layer/mesoporous layer/insulating scaffold layer/perovskite active layer thin film electrode Place the transparent conductive glass/electron transport layer/mesoporous layer/insulating scaffold layer thin film electrode prepared in step 3) on the heating table to preheat for 10 minutes, then dropwise add 50°C mixed cationic perovskite (FA) _x (MA) _{1 -x} PbI ₃ precursor solution was spin-coated at 1800 rpm for 3 seconds, then at 3600 rpm for 30 seconds, then placed on a 100°C heating stage, heated and kept for crystallization for 50 minutes, and mixed with cationic perovskite (FA) _x ( MA) _1-x PbI ₃ precursor liquid crystallizes on the gaps and surfaces of the mesoporous layer and the insulating scaffold layer, thereby obtaining a transparent conductive glass/electron transport layer/mesoporous layer/insulating scaffold layer/perovskite active layer thin film electrode; 5) Obtain perovskite solar cells After scraping the conductive carbon slurry on the transparent conductive glass/electron transmission layer/mesoporous layer/insulating scaffold layer/perovskite active layer thin film electrode prepared in step 4), cure it at 100°C for 15 minutes to prepare a carbon electrode, thereby obtaining a stable of perovskite solar cells. 2. The liquid phase preparation method according to claim 1, wherein in step 1), the preparation process of the mixed cationic perovskite (FA) _x (MA) _1-x PbI ₃ precursor liquid includes: Put lead iodide and methylamine iodide into anhydrous N,N-dimethylformamide and use ultrasound to completely dissolve them to obtain a DMF solution of MAPbI ₃ ; put lead iodide and formamidine iodide into anhydrous In N,N-dimethylformamide, use ultrasound to completely dissolve it to obtain a DMF solution of FAPbI ₃ ; Mix the DMF solution of MAPbI ₃ and the DMF solution of FAPbI ₃ according to a certain amount of substances to obtain a mixed cationic perovskite (FA) _x (MA) _1-x PbI ₃ precursor solution.