WO2019148326A1 - Method for preparing perovskite thin film and application thereof - Google Patents

Abstract

A method for preparing a perovskite thin film, at least comprising the following steps: step S01, performing a preheating treatment on a substrate and a perovskite precursor solution under air conditions; step S02, dripping the pre-heated perovskite precursor solution onto a surface of the substrate under air and heat radiation conditions, and then performing a coating treatment on a coating device; and step S03, performing an annealing treatment on the substrate subjected to the coating treatment in step S02, and obtaining a perovskite thin film. The method utilizes a manner of heat radiation to achieve the preparation of a perovskite thin film under air conditions, and the obtained perovskite thin film has a photoelectric conversion efficiency thereof that reaches 16.44%, and that may achieve the technical effect of being consistent with a photoelectrical conversion efficiency of a perovskite thin film prepared under a nitrogen atmosphere in a glove box.

Description

Preparation method of perovskite film and application thereof Technical field

The invention belongs to the technical field of perovskite thin films, and particularly relates to a preparation method of a perovskite film and an application thereof.

Background technique

Since Akihiro Kojima first prepared a solar cell with a perovskite material as a light absorbing layer with a photoelectric conversion efficiency of 3.8% in 2009, the research on the use of a perovskite material as a solar cell light absorbing layer has been continuously developed. In 2013, Gratzel research team synthesized the organometallic halide perovskite-based solar cell with planar heterojunction structure by means of meteorological deposition method on the basis of improving the original process method, with an efficiency of 15%. A historic breakthrough, the breakthrough was named one of the top ten scientific breakthroughs by Science magazine in the same year. As of December 2017, for the research of perovskite solar cells, the research results of the photoelectric conversion efficiency of 22.7% have been obtained in the glove box and under the protection of inert gas. Although it has a history of less than 10 years, the photoelectric conversion efficiency of perovskite solar cells is close to that of single crystal silicon, and because of its simple preparation process and low cost, it can be made into a flexible battery, so it has a very broad market. prospect.

At present, the film forming technology of perovskite solar cells mainly includes spin coating, blade coating, inkjet printing, gas phase assisted deposition and the like. Among the above methods, the perovskite film prepared by the spin coating method has uniform compactness and less defects, so that the obtained battery has high efficiency, and the spin coating method is also a method commonly used by researchers in the laboratory.

Since perovskite is decomposed as soon as water and oxygen are encountered, perovskite solar cells are currently produced under a nitrogen atmosphere and in a glove box. The glove box preparation process mainly includes normal temperature spin coating (normal temperature of substrate, normal temperature of spin coating process) and preheating spin coating of substrate (preheating of substrate before spin coating, but not heating during spin coating). The perovskite solar cell prepared by the glove box spin coating process under a nitrogen atmosphere has a device with a maximum efficiency of 22.7%, but the perovskite solar cell prepared in a glove box and under a nitrogen atmosphere has great limitations. Industrialization cannot be achieved. In addition, when the spin coating process of the glove box is directly transferred to the air for the preparation of the perovskite solar cell, the obtained battery device is very inefficient. If it is spin-coated in the air by a normal temperature spin coating process, the surface of the obtained perovskite film is as shown in Fig. 1. The perovskite film obtained from Fig. 1 has more pores, which will seriously limit the perovskite solar cell. Photoelectric conversion efficiency. Another example is the spin coating of the substrate in the air by a preheating spin coating process. The surface of the obtained perovskite film is as shown in Fig. 2. The perovskite film obtained from Fig. 2 has a hole which is less than the normal temperature spin coating, but there is still Many holes will also limit the photoelectric conversion efficiency of perovskite solar cells.

technical problem

The technical problem to be solved by the present invention is to provide a preparation method of a perovskite film to solve the problem that the existing perovskite film cannot be prepared in air, and the film pores existing in the perovskite film prepared by air spin coating are large. , low efficiency of photoelectric conversion and other issues.

Further, the present invention also provides the use of the perovskite film.

Technical solution

In order to achieve the above object, the technical solution adopted by the present invention is as follows:

A method for preparing a perovskite film comprises at least the following steps:

Step S01. preheating the substrate and the perovskite precursor solution under air conditions;

Step S02. The pre-heated perovskite precursor solution is dropped on the surface of the preheated substrate under air and heat radiation conditions, and then subjected to a coating treatment on the coating device;

Step S03. The step S02 is subjected to coating treatment to obtain a substrate for annealing treatment to obtain a perovskite film.

Accordingly, a photovoltaic device includes a perovskite film prepared by the above-described method for preparing a perovskite film.

Further, a perovskite solar cell comprising a light absorbing layer provided by the method for preparing a perovskite film as described above.

Beneficial effect

Compared with the prior art, the method for preparing a perovskite film provided by the present invention prepares a perovskite film by coating in air by preheating and heat radiation, and the obtained perovskite film has few holes or even no pores, and compactness. Good, and the photoelectric efficiency reached 16.44%. Under the same structure, the effect of the photoelectric efficiency of the perovskite film prepared in the glove box and under the nitrogen atmosphere can be achieved. In addition, the preparation method is convenient and simple, is suitable for large-scale production, and has practical application significance.

The optoelectronic device provided by the invention has the characteristics that the device structure comprises the perovskite film prepared by the above-mentioned preparation method of the perovskite film, and has the characteristics of less pores or even no pores and good compactness, so that the photoelectric efficiency of the photovoltaic device reaches 16.44%.

The perovskite solar cell provided by the invention has the effect that the light absorption layer is prepared by the preparation method of the perovskite film of the invention, and the light absorption layer has the effect of less holes or even no holes, exhibits good compactness, and the obtained solar cell has high efficiency. 16.44%.

DRAWINGS

1 is an SEM image of a perovskite film obtained by spin coating of a normal temperature spin coating process in air;

2 is an SEM image of a perovskite film obtained by spin coating of a substrate preheating spin coating process in air;

3 is a schematic view showing a preparation process of a perovskite film provided by the present invention;

4 is an SEM image of a perovskite film prepared in Example 1 of the present invention;

5 is a comparative diagram of a perovskite film prepared in Comparative Example 1, Comparative Example 2, and Inventive Example 1;

6 is an XRD chart of a perovskite film prepared in Comparative Example 1, Comparative Example 2, and Inventive Example 1;

7 is a UV-via curve of a perovskite solar cell made of a perovskite film prepared in Comparative Example 1, Comparative Example 2, and Inventive Example 1;

8 is a J-V curve of a perovskite solar cell prepared from the perovskite film prepared in Comparative Example 1, Comparative Example 2, and Inventive Examples 1 to 4;

9 is a graph showing photoelectric conversion efficiency distribution of a perovskite solar cell prepared by using a perovskite film prepared in Comparative Example 1, Comparative Example 2, and Inventive Examples 1 to 4;

10 is a schematic structural view of a perovskite solar cell made of a perovskite film prepared in Example 1 of the present invention;

Wherein, 1-substrate; 2-hole transport layer; 3-light absorbing layer; 4-electron transport layer; 5-buffer layer; 6-metal conductive electrode.

Embodiments of the invention

In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly, the present invention will be further described in detail below with reference to the embodiments and the accompanying drawings. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The terminology involved in the present invention is explained:

Substrate: refers to the material used to carry the perovskite precursor. The perovskite precursor forms a perovskite film on the surface of the substrate. After the perovskite film is formed, the substrate can be removed or retained. In some cases, the substrate has the same meaning as the substrate and the substrate. For example, when the perovskite film is made into a solar cell light absorbing layer, the substrate is the substrate, and the substrate may be ITO or FTO. PEN, PET, or the like may also be ITO, FTO, PEN, PET, or the like including a carrier transport layer (which may be a hole transport layer or an electron transport layer).

Referring to FIG. 3, the present invention provides a method for preparing a perovskite film.

Specifically, the method for preparing the perovskite film comprises at least the following steps:

Step S01. preheating the substrate and the perovskite precursor solution under air conditions;

Step S02. The pre-heated perovskite precursor solution is dropped on the surface of the preheated substrate under air and heat radiation conditions, and then subjected to a coating treatment on the coating device;

Step S03. The step S02 is subjected to coating treatment to obtain a substrate for annealing treatment to obtain a perovskite film.

The following is a detailed explanation of the preparation method of the above perovskite film:

The coating device according to the present invention may be a homogenizing device or a knife coating device. Specifically, it may be a homogenizer or a knife coater. If it is a homogenizer, it needs to preheat the suction cup of the homogenizer; if it is a scraper, it needs to preheat the scraper and the scraping platform at the same time.

Preferably, the coating device can also be pre-heat treated, preheating to 70-85 ° C, the temperature is too low, residual moisture, is not conducive to the coating of the perovskite precursor, the temperature is too high, heat radiation occurs The perovskite strong body temperature is too high to produce non-perovskite.

During the preheating of the coating device, the coating device and the substrate may be separately preheated; the coating device may be placed together with the substrate and then preheated; and the coating device, the substrate and the calcium may be further applied. The titanium ore precursor solution is preheated together. When the three are placed in the same environment for preheating, it is only necessary to preheat the three to 70~85 °C. If the preheating is separately performed, the substrate needs to be preheated to 90~110 °C, and the preheating time is at least 10 min, so as to avoid temperature drop when the preheated substrate is transferred to the coating equipment, which is unfavorable for the perovskite precursor solution. Crystallization produces perovskites.

Preferably, the concentration of the perovskite precursor solution is 0.8 to 1.5 mmol/mL. The perovskite film obtained in the concentration range has good surface compactness, no foamy pores, and the concentration range of the perovskite precursor solution is made into a perovskite film for use in a perovskite solar cell, and the efficiency is Up to 13.48~16.44%.

In the perovskite precursor solution, the perovskite precursor is a mixture of two halogen salts A and B of the structural formula ABX ₃ mixed with a halogenated alkane M, wherein A is methylamine, methyldiamine, hydrazine Any one of indium, B is any one of lead and tin, and X is any one of chlorine, bromine and iodine. The solvent of the perovskite precursor solution is dimethylformamide (DMF) or dimethyl sulfoxide (DMSO). Preferably, the perovskite precursor solution is preheated to 70-85 °C. Make it consistent with the temperature of heat radiation heating, to ensure that the solution, substrate has a small temperature difference or even no temperature difference, to avoid stress in the crystallization process, resulting in cracks in the film.

Further preferably, the perovskite precursor is CH ₃ NH ₃ PbI ₃ . The perovskite precursor uses lead acetate as a lead source and methyl iodide as a raw material to react methyl iodide with lead acetate to form CH ₃ NH ₃ PbI ₃ . Simultaneously produce monomethylamine (CH ₃ NH ₂ ) and acetic acid (CH ₃ COOH). Monomethylamine and acetic acid can be completely volatilized when spin-coated under heat radiation conditions, avoiding volatilization during annealing and causing surface of perovskite film. A bubble-like hole appears.

The heat radiation condition involved in the step S02 of the present invention refers to the fact that the strong body solution of the perovskite is dropped on the surface of the substrate until the end of the coating process, and the whole process is irradiated with a heat radiation source. Through the irradiation of the heat radiation source, the temperature of the entire spin coating process is stabilized, so that the perovskite crystallizes directly in the perovskite precursor solution, and other substances generated during the reaction process can be quickly volatilized to avoid residual components. Volatilization during subsequent annealing results in the appearance of bubble-like pores, thereby ensuring the compactness of the obtained perovskite film. The purpose of heat radiation is to accelerate the evaporation of the solvent and accelerate the crystallization. On the other hand, the volatile solvent can inhibit the dissolution of water and oxygen into the perovskite precursor solution or adhere to the surface of the formed perovskite film to a certain extent. Resists the damage of the formed perovskite film by water oxygen; when the temperature is too high, non-perovskite is formed.

Preferably, the heat radiation source may be an incandescent lamp, a tungsten halogen lamp or the like. In the process of step S02, it is also necessary to use a temperature detector (thermocouple) to sense and monitor the temperature of the surface of the substrate. When the surface temperature of the substrate changes, the power of the heat radiation source, the distance from the substrate, and the like are adjusted in time. Conditions such that the substrate surface temperature is equalized. For example, when the coating device is a homogenizing device, the thermocouple senses the temperature of the surface of the substrate and the temperature of the surface of the suction device, and adjusts the radiation condition of the heat radiation source to ensure that the temperature of the whole homogenizer is constant during the spin coating process or Has not changed much.

Preferably, the spin coating speed is 4000 to 8000 r/min. The spin coating speed is too high, which is not conducive to the thickness control of the film formation. At the spin coating speed, the obtained perovskite crystal layer has a thickness of 300 to 500 nm.

Preferably, the relative humidity of the air in step S02 is less than or equal to 50%. If the relative humidity is too high, it is not conducive to film formation, and it is easy to cause oxidation of the perovskite and the performance of the device is lowered.

In step S03, the annealing temperature of the annealing treatment is 90 to 100 ° C, and the annealing time is 5 to 10 minutes. Since the volatile component produced by the perovskite precursor solution of the present invention during the spin coating process has volatilized under the condition of heat radiation, in the annealing crystallization process, only a further crystallization process occurs without volatilization of the volatile component, avoiding Since the volatilization rate of the volatile component is lower than the crystallization rate, a bubble-like hole appears on the surface of the perovskite film to ensure a dense perovskite film product after annealing.

The preparation method of the perovskite film provided by the invention obtains a perovskite film by coating in air by preheating and heat radiation, and the obtained perovskite film has few holes or even no holes, has good compactness, and has photoelectric efficiency. 16.44%, can achieve the technical effect of the photoelectric efficiency of the perovskite film prepared under the nitrogen atmosphere combined with the glove box. In addition, the preparation method is convenient and simple, is suitable for large-scale production, and has practical application significance.

The present invention further provides a photovoltaic device according to the method for preparing the above-described perovskite film, the photovoltaic device comprising at least a perovskite film, and the perovskite film of the photovoltaic device is the invention The preparation method of the above perovskite film is prepared and prepared.

Further, the photovoltaic device of the present invention is a perovskite solar cell, and the structure of the perovskite solar cell may be a forward structure or a reverse structure. Wherein, the structure of the perovskite solar cell of the forward structure is: metal oxide conductive substrate/electron transport layer/perovskite film layer/hole transport layer/metal conductive silver layer; reverse structure perovskite solar cell The structure is: metal oxide conductive substrate / hole transport layer / perovskite film layer / electron transport layer / metal conductive aluminum layer.

In one embodiment, a structure of the perovskite solar cell is as shown in FIG. 10 , and specifically includes a substrate 1 and a hole transport layer 2 and a perovskite film stacked in this order from a surface of the substrate 1 . Layer (light absorbing layer) 3, electron transport layer 4, buffer layer 5, and metal conductive electrode 6.

The material of the substrate 1 is any one of ITO, FTO, PEN, and PET.

The material of the hole transport layer 2 is PEDOT:PSS, PEDOT, NiO, PTAA.

The material having an electron transport layer of 4 is C ₆₀ , PCBM, or the like.

The material of the buffer layer 5 is BCP.

The material of the metal conductive electrode 6 is silver or aluminum.

In one embodiment, the method for preparing the perovskite solar cell is as follows:

(a) ultrasonically cleaning the substrate with a washing liquid to obtain a clean substrate;

(b) UV treatment for 20~30min;

(c) placing the substrate obtained in the step (b) on a homogenizer, and spin coating a hole transport layer;

(d). The substrate comprising the hole transport layer obtained in the step (c) is placed on a heating platform, and preheated at 90 to 110 ° C for at least 10 min;

(e) preheating the perovskite precursor solution in an environment of 70-85 ° C for at least 5 min;

(f) Place a heat radiation source (such as an incandescent lamp) above the homogenizer, adjust the temperature of the surface of the suction cup by controlling the current, and monitor the temperature in real time with a thermocouple to ensure that the temperature of the surface of the suction cup is 70~85. °C;

(g). Continuous heat radiation, control the relative humidity of the air around the homogenizer to be less than or equal to 50%, and quickly transfer the preheated substrate in step (d) to the suction cup of the homogenizer to preheat the perovskite. The precursor solution is dropped on the surface of the hole transport layer, and after the substrate temperature is 70-85 ° C, the spin coating treatment is performed at a speed of 4000-8000 r/min to obtain a perovskite layer having a thickness of 300-500 nm;

(h). The substrate comprising the perovskite layer obtained in the step (g) is placed on a heating platform, and annealed at 90 to 100 ° C for 5 to 10 minutes, and then naturally cooled to room temperature;

(i) transferring the substrate containing the perovskite film obtained in the step (h) to a thermal evaporation system, and sequentially evaporating the electron transport layer, the buffer layer, and the metal conductive electrode on the surface of the perovskite film, and steaming The plated electron transport layer has a thickness of 20 to 40 nm, the vapor deposited buffer layer has a thickness of 4 to 10 nm, and the metal conductive electrode has a thickness of 100 to 200 nm.

In order to better illustrate the preparation method of the perovskite film provided by the embodiment of the present invention, the following further explains by an embodiment of preparing a perovskite solar cell.

Example 1

A method for preparing a perovskite solar cell, comprising the steps of:

(1). The ITO substrate is washed with detergent, deionized water, acetone, and isopropyl alcohol in sequence.

(2) The ITO substrate after the cleaning step (1) was blown dry with nitrogen, and irradiated with a UV machine for 30 minutes.

(3). The ITO substrate obtained in the step (2) was placed in a homomixer, and PEDOT was spin-coated at a speed of 4000 r/min to obtain a hole transport layer having a thickness of 30 nm.

(4). Methyl iodide and lead acetate are dissolved in DMF according to a molar ratio of 3:1 to obtain a 1 mmol/mL perovskite precursor solution, and the obtained perovskite precursor solution is obtained. Place on a heating platform, preheat at 80 °C for 5 min, then filter with a 0.45 μm filter and set aside.

(5). The ITO substrate with the hole transport layer obtained in the step (3) was placed on a heating platform and preheated at 80 ° C for 10 min.

(6). Add incandescent lamp as the heat radiation source above the commercial homogenizer, and use the thermocouple to detect the surface temperature of the suction cup of the commercial homogenizer to ensure that the temperature of the surface of the suction cup is stable at 80 °C and above.

(7) transferring the ITO substrate with the hole transport layer onto the suction cup of the step (6), and taking 50 μL of the perovskite precursor solution of the step (4) dropwise onto the surface of the hole transport layer. With 4000 The spin coating speed of r/min was spin-coated, spin-coated for 30 s, and the incandescent lamp continued to radiate heat during spin coating to obtain a perovskite layer coated on the surface of the hole transport layer.

(8). The device obtained in the step (7) was placed on a heating table, annealed at 95 ° C for 5 min, and then naturally cooled to room temperature.

(9). Transfer the device obtained in the step (8) to the evaporation chamber, and sequentially vapor-deposit 30 nm C ₆₀ (electron transport layer), 8 nm buffer layer (BCP), 100 on the surface of the perovskite layer. Ag (metal conductive electrode) of nm, and thus, the perovskite solar cell of Example 1 was obtained.

Example 2

A method for preparing a perovskite solar cell, comprising the steps of:

(1). The ITO substrate is washed with detergent, deionized water, acetone, and isopropyl alcohol in sequence.

(2) The ITO substrate after the cleaning step (1) was blown dry with nitrogen, and irradiated with a UV machine for 30 minutes.

(3). The ITO substrate obtained in the step (2) was placed in a homomixer, and PEDOT was spin-coated at a speed of 4000 r/min to obtain a hole transport layer having a thickness of 30 nm.

(4). Methyl iodide and lead acetate are dissolved in DMF according to a molar ratio of 3:1, respectively, and a perovskite precursor solution of 0.8 mmol/mL is obtained, and the obtained perovskite precursor is obtained. The solution was placed on a heating platform, preheated at 80 °C for 5 min, and then filtered through a 0.45 μm filter head for use.

(5). The ITO substrate with the hole transport layer obtained in the step (3) was placed on a heating platform and preheated at 80 ° C for 10 min.

(6). Add incandescent lamp as the heat radiation source above the commercial homogenizer, and use the thermocouple to detect the surface temperature of the suction cup of the commercial homogenizer to ensure that the temperature of the surface of the suction cup is stable at 80 °C and above.

(7) transferring the ITO substrate with the hole transport layer onto the suction cup of the step (6), and taking 50 μL of the perovskite precursor solution of the step (4) dropwise onto the surface of the hole transport layer. With 4000 The spin coating speed of r/min was spin-coated, spin-coated for 30 s, and the incandescent lamp continued to radiate heat during spin coating to obtain a perovskite layer coated on the surface of the hole transport layer.

(8). The device obtained in the step (7) was placed on a heating table, annealed at 95 ° C for 5 min, and then naturally cooled to room temperature.

(9). Transfer the device obtained in the step (8) to the evaporation chamber, and sequentially vapor-deposit 30 nm C ₆₀ (electron transport layer), 8 nm buffer layer (BCP), 100 on the surface of the perovskite layer. Ag (metal conductive electrode) of nm, and thus, the perovskite solar cell of Example 3 was obtained.

Example 3

A method for preparing a perovskite solar cell, comprising the steps of:

(1). The ITO substrate is washed with detergent, deionized water, acetone, and isopropyl alcohol in sequence.

(2) The ITO substrate after the cleaning step (1) was blown dry with nitrogen, and irradiated with a UV machine for 30 minutes.

(3). The ITO substrate obtained in the step (2) was placed in a homomixer, and PEDOT was spin-coated at a speed of 4000 r/min to obtain a hole transport layer having a thickness of 30 nm.

(4). Methyl iodide and lead acetate are dissolved in DMF according to a molar ratio of 3:1, respectively, to obtain a 1.2 mmol/mL perovskite precursor solution, and the obtained perovskite precursor is obtained. The solution was placed on a heating platform, preheated at 80 °C for 5 min, and then filtered through a 0.45 μm filter head for use.

(5). The ITO substrate with the hole transport layer obtained in the step (3) was placed on a heating platform and preheated at 80 ° C for 10 min.

(6). Add incandescent lamp as the heat radiation source above the commercial homogenizer, and use the thermocouple to detect the surface temperature of the suction cup of the commercial homogenizer to ensure that the temperature of the surface of the suction cup is stable at 80 °C and above.

(7) transferring the ITO substrate with the hole transport layer onto the suction cup of the step (6), and taking 50 μL of the perovskite precursor solution of the step (4) dropwise onto the surface of the hole transport layer. With 4000 The spin coating speed of r/min was spin-coated, spin-coated for 30 s, and the incandescent lamp continued to radiate heat during spin coating to obtain a perovskite layer coated on the surface of the hole transport layer.

(8). The device obtained in the step (7) was placed on a heating table, annealed at 95 ° C for 5 min, and then naturally cooled to room temperature.

(9). Transfer the device obtained in the step (8) to the evaporation chamber, and sequentially vapor-deposit 30 nm C ₆₀ (electron transport layer), 8 nm buffer layer (BCP), 100 on the surface of the perovskite layer. Ag (metal conductive electrode) of nm, and thus, the perovskite solar cell of Example 3 was obtained.

Example 4

A method for preparing a perovskite solar cell, comprising the steps of:

(1). The ITO substrate is washed with detergent, deionized water, acetone, and isopropyl alcohol in sequence.

(2) The ITO substrate after the cleaning step (1) was blown dry with nitrogen, and irradiated with a UV machine for 30 minutes.

(3). The ITO substrate obtained in the step (2) was placed in a homomixer, and PEDOT was spin-coated at a speed of 4000 r/min to obtain a hole transport layer having a thickness of 30 nm.

(4). Methyl iodide and lead acetate are dissolved in DMF according to a molar ratio of 3:1, respectively, and a perovskite precursor solution of 1.5 mmol/mL is obtained, and the obtained perovskite precursor is obtained. The solution was placed on a heating platform, preheated at 80 °C for 5 min, and then filtered through a 0.45 μm filter head for use.

(5). The ITO substrate with the hole transport layer obtained in the step (3) was placed on a heating platform and preheated at 80 ° C for 10 min.

(6). Add incandescent lamp as the heat radiation source above the commercial homogenizer, and use the thermocouple to detect the surface temperature of the suction cup of the commercial homogenizer to ensure that the temperature of the surface of the suction cup is stable at 80 °C and above.

(7) transferring the ITO substrate with the hole transport layer onto the suction cup of the step (6), and taking 50 μL of the perovskite precursor solution of the step (4) dropwise onto the surface of the hole transport layer. With 4000 The spin coating speed of r/min was spin-coated, spin-coated for 30 s, and the incandescent lamp continued to radiate heat during spin coating to obtain a perovskite layer coated on the surface of the hole transport layer.

(8). The device obtained in the step (7) was placed on a heating table, annealed at 95 ° C for 5 min, and then naturally cooled to room temperature.

(9). Transfer the device obtained in the step (8) to the evaporation chamber, and sequentially vapor-deposit 30 nm C ₆₀ (electron transport layer), 8 nm buffer layer (BCP), 100 on the surface of the perovskite layer. Ag (metal conductive electrode) of nm, and thus, the perovskite solar cell of Example 4 was obtained.

Comparative example 1

A method for preparing a perovskite solar cell, comprising the steps of:

(1). The ITO substrate is washed with detergent, deionized water, acetone, and isopropyl alcohol in sequence.

(2) The ITO substrate after the cleaning step (1) was blown dry with nitrogen, and irradiated with a UV machine for 30 minutes.

(3). The ITO substrate obtained in the step (2) was placed in a homomixer, and PEDOT was spin-coated at a speed of 4000 r/min to obtain a hole transport layer having a thickness of 30 nm.

(4). Methyl iodide and lead acetate are dissolved in DMF according to a molar ratio of 3:1 to obtain a 1 mmol/mL perovskite precursor solution, and the obtained perovskite precursor solution is obtained. Place on a heating platform, preheat at 80 °C for 5 min, then filter with a 0.45 μm filter and set aside.

(5). The ITO substrate with the hole transport layer obtained in the step (3) is placed on the homogenizer, and 50 μL of the perovskite precursor solution of the step (4) is added dropwise to the surface of the hole transport layer to 4000 The spin coating speed of r/min was spin-coated and spin-coated for 30 s to obtain a perovskite layer coated on the surface of the hole transport layer.

(6). The device obtained in the step (5) was placed on a heating table, annealed at 95 ° C for 5 min, and then naturally cooled to room temperature.

(7). Transfer the device obtained in the step (6) to the evaporation chamber, and sequentially vapor-deposit 30 nm C ₆₀ (electron transport layer), 8 nm buffer layer (BCP), 100 on the surface of the perovskite layer. Ag (metal conductive electrode) of nm, and thus, a perovskite solar cell of Comparative Example 1 was obtained.

Comparative example 2

A method for preparing a perovskite solar cell, comprising the steps of:

(1). The ITO substrate is washed with detergent, deionized water, acetone, and isopropyl alcohol in sequence.

(2) The ITO substrate after the cleaning step (1) was blown dry with nitrogen, and irradiated with a UV machine for 30 minutes.

(3). The ITO substrate obtained in the step (2) was placed in a homomixer, and PEDOT was spin-coated at a speed of 4000 r/min to obtain a hole transport layer having a thickness of 30 nm.

(4). Methyl iodide and lead acetate are dissolved in DMF according to a molar ratio of 3:1 to obtain a 1 mmol/mL perovskite precursor solution, and the obtained perovskite precursor solution is obtained. Place on a heating platform, preheat at 80 °C for 5 min, then filter with a 0.45 μm filter and set aside.

(5). The ITO substrate with the hole transport layer obtained in the step (3) was placed on a heating table and preheated at 100 ° C for 10 min.

(6). The substrate preheated in step (5) is placed in a homogenizer, the temperature of the substrate is kept at 100 ° C, and 50 μL of the perovskite precursor solution of step (4) is added dropwise to the cavity. Transport layer surface to 4000 The spin coating speed of r/min was spin-coated and spin-coated for 30 s to obtain a perovskite layer coated on the surface of the hole transport layer.

(7). The device obtained in the step (6) was placed on a heating table, annealed at 95 ° C for 5 min, and then naturally cooled to room temperature.

(8). Transfer the device obtained in the step (7) to the evaporation chamber, and sequentially vapor-deposit 30 nm C ₆₀ (electron transport layer), 8 nm buffer layer (BCP), 100 on the surface of the perovskite layer. Ag (metal conductive electrode) of nm, and thus, a perovskite solar cell of Comparative Example 2 was obtained.

In order to better illustrate the properties of the perovskite film prepared by the method for preparing a perovskite film of the present invention, relevant performance tests and test items of the perovskite film and the perovskite solar cell obtained in the examples and the comparative examples were carried out. Including microtopography, XRD, UV-via curve, JV curve, photoelectric conversion efficiency.

(1). Micromorphology: The morphology of the perovskite film obtained after annealing in Example 1, Comparative Example 1, and Comparative Example 2 was tested by scanning electron microscopy. The details are shown in Figure 1, Figure 2 and Figure 4. At the same time, a general pixel camera is used for photographing during the spin coating process, as shown in FIG. 5 .

It can be seen from the comparison of the SEM images of Figs. 1, 2, and 4 that, with the preparation method of the present invention, the perovskite film prepared has a small bubble-like pores with a small amount of bubble-like pores in Fig. 1 and Fig. 2, and the pore diameter is small, microscopic. The morphological integrity is better. As can be seen from FIG. 5, the apparent color of the embodiment 1 of the present invention is dark brown, which is darker than that of the comparative example 1 and the comparative example 2, indicating calcium in the spin coating of the embodiment 1 of the present invention. Titanium ore has crystallized from the perovskite precursor, while Comparative Example 1 and Comparative Example 2 crystallized during the annealing process. Since the perovskite film prepared by the present invention has good microscopic surface consistency, the perovskite film obtained in Examples 2 to 4 was not subjected to a corresponding SEM scan test.

(2). XRD phase analysis: The material corresponding to the 12.8 degree peak is the product of lead iodide or perovskite decomposition. It can be seen from the figure that there is almost no iodine in the perovskite film prepared by the thermal radiation method. The peak of lead shows that the obtained perovskite is not decomposed by preparation in air, and the perovskite film prepared by the other two methods has a peak of lead iodide, indicating that perovskite has occurred. Partial decomposition. The XRD results show that the thermal radiation method can completely convert the precursor into perovskite, and to some extent, avoid the harm of water and oxygen.

(3) UV-via curve analysis: The UV-via curve test was performed on the perovskite solar cells obtained in Example 1, Comparative Example 1, and Comparative Example 2 using an ultraviolet-visible spectrometer. The test results are shown in Fig. 7. It can be seen from Fig. 7 that the film prepared by the thermal radiation method has better absorption of visible light, which is one of the reasons why the current of the device prepared by the thermal radiation method is higher than the other two methods.

(4). J-V curve analysis: The J-V curve test was performed on the perovskite solar cells obtained in Examples 1 to 4, Comparative Example 1, and Comparative Example 2 using AM1.5G solar spectrum, and the test results are shown in Fig. 8.

As can be seen from FIG. 8, the open-circuit voltage (V _OC ) of the perovskite solar cell obtained in the first embodiment of the present invention is 0.958 V, and the short-circuit current Density (J _SC ) is 22.26. mA/cm ² , Fill Factor (abbreviated as FF) 72.51%; battery performance parameters in Example 2: Voc=0.93 V, Jsc=18.84 mA/cm ² , FF=76.88%; battery of Example 3 Performance parameters: Voc=0.92 V, Jsc=22.91 mA/cm ² , FF=77.99%; battery performance parameters of Example 4: Voc=0.90 V, Jsc=21.70 mA/cm ² , FF=79.94%. In Comparative Example 1, V _OC = 0.90 V, J _SC = 2.03 mA/cm ² , and FF = 75.93%; in Comparative Example 2, V _OC = 0.97 V, J _SC = 15.63 mA/cm ² , FF = 70.35% .

It can be seen from the photoelectric conversion efficiency diagram of FIG. 9 that the photoelectric conversion efficiencies (PCE) of the perovskite solar cells of Examples 1 to 4 of the present invention are 15.47%, 13.48%, 16.44%, and 15.69%, respectively, and the PCE of Comparative Example 1 is 1.40. %, PCE of Comparative Example 2 = 10.68%. It can be seen that the present invention increases the heat radiation under air conditions, and the obtained photoelectric conversion efficiency of the perovskite solar cell is higher than that under the air condition without increasing the heat radiation.

Under normal conditions, a perovskite film is generally prepared in a glove box in combination with a nitrogen atmosphere. The perovskite solar cell obtained by the preparation of the perovskite film in the glove box combined with the nitrogen atmosphere has a photoelectric efficiency of only 16.2%, and the present invention increases the heat radiation under the air condition, and obtains the photoelectric conversion of the perovskite solar cell. The efficiency reaches 16.44%, which indicates that the invention realizes a breakthrough in preparing a perovskite film from a glove box under nitrogen conditions and preparing a perovskite film under air conditions combined with heat radiation, that is, industrialization can be realized.

The above is only the 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 of the present invention. Within the scope.

Claims (13)

A method for preparing a perovskite film, comprising: at least comprising the following steps: Step S01. preheating the substrate and the perovskite precursor solution under air conditions; Step S02. The pre-heated perovskite precursor solution is dropped on the surface of the substrate under air and heat radiation conditions, and then subjected to a coating treatment on the coating device; Step S03. The step S02 is subjected to coating treatment to obtain a substrate for annealing treatment to obtain a perovskite film. The method of preparing a perovskite film according to claim 1, wherein the heat radiation condition is a heat radiation source. The method for producing a perovskite film according to any one of claims 1 to 2, wherein the pre-heating temperature of the perovskite precursor solution is 70 to 85 °C. The method for producing a perovskite film according to any one of claims 1 to 2, wherein the concentration of the perovskite precursor solution is 0.8 to 1.5 mmol/mL. The method for preparing a perovskite film according to claim 1, wherein the coating method is spin coating or blade coating. The method for preparing a perovskite film according to any one of claims 1 to 2, wherein the perovskite precursor in the perovskite precursor solution has a structural formula of ABX ₃ , wherein A Any one of methylamine, methyldiamine, hydrazine, and indium, B is any one of lead and tin, and X is any one of chlorine, bromine, and iodine; and the perovskite precursor solution The solvent is dimethylformamide or dimethyl sulfoxide. The method of producing a perovskite film according to claim 1, wherein the relative humidity of the air is ≤ 50%. The method of producing a perovskite film according to claim 1, wherein the substrate has a preheating temperature of 90 to 110 °C. The method of producing a perovskite film according to claim 1, wherein the annealing treatment temperature is 90 to 100 °C. A photovoltaic device comprising a perovskite film, characterized in that the perovskite film is obtained by the method for producing a perovskite film according to any one of claims 1 to 9. A perovskite solar cell, the perovskite solar cell comprising a light absorbing layer, wherein the light absorbing layer is the calcium titanium obtained by the method for preparing a perovskite film according to any one of claims 1 to 9. Mineral film. A perovskite solar cell according to claim 11, wherein the structure of the perovskite solar cell is a forward structure or a reverse structure. The perovskite solar cell according to claim 11 or 12, wherein the structure of the perovskite solar cell is a metal oxide conductive substrate/electron transport layer/perovskite film layer/hole transport layer / metal conductive silver layer; or metal oxide conductive substrate / hole transport layer / perovskite film layer / electron transport layer / metal conductive aluminum layer.