阅读说明：本技术 氢碘酸修饰的锡铅混合钙钛矿太阳能电池及其制备方法 (Hydriodic acid modified tin-lead mixed perovskite solar cell and preparation method thereof ) 是由 吴静 罗东向 黄润达 刘霄 张梦龙 于 2021-08-19 设计创作，主要内容包括：本发明涉及钙钛矿太阳能电池领域,更具体地,涉及一种氢碘酸修饰的锡铅混合钙钛矿太阳能电池及其制备方法,所述氢碘酸修饰的锡铅混合钙钛矿太阳能电池,由上而下依次包括透明电极、空穴传输层、锡铅混合钙钛矿层、电子传输层、电子阻挡层以及对电极,所述锡铅混合钙钛矿层为在锡铅混合钙钛矿前驱体溶液中加入无机氢碘酸溶液后制成,通过无机氢碘酸的修饰,可抑制锡铅混合钙钛矿层中的锡离子氧化,降低钙钛矿薄膜的缺陷密度并改善钙钛矿薄膜的结晶,提高钙钛矿太阳能电池的器件稳定性和光电转换效率。(The invention relates to the field of perovskite solar cells, in particular to a hydroiodic acid modified tin-lead mixed perovskite solar cell and a preparation method thereof.)

1. A hydriodic acid modified tin-lead mixed perovskite solar cell sequentially comprises a transparent electrode, a hole transport layer, a tin-lead mixed perovskite layer, an electron transport layer, an electron blocking layer and a counter electrode from top to bottom.

2. The hydriodic acid modified tin-lead mixed perovskite solar cell according to claim 1, wherein the molar ratio of the inorganic hydriodic acid to the sum of lead ions and tin ions in the tin-lead mixed perovskite precursor solution is (1-2): 10: 10.

3. The hydroiodic acid-modified tin-lead mixed perovskite solar cell of claim 1,

the transparent electrode is made of a substrate material doped with one or more mixtures of ITO, FTO, AZO or ATO;

the hole transport layer is made of one or a mixture of PEDOT, PSS, PTAA or Poly-TPD;

the tin-lead mixed perovskite layer is made of MASn_xPb_1-xI₃、FASn_xPb_1-x I₃、MA_xFA_1-x Sn_yPb_1-yI3、FA_bCs_1-bSn_xPb₁-xI₃、(FASnI₃)_1-x(MAPbI₃)_xOne or more mixtures of (a);

the material of the electron transport layer is C₆₀Or PC₆₁One or two mixtures of BM;

the electron blocking layer is one or a mixture of two of BCP or ZnO;

the counter electrode is made of one or a mixture of Au, Ag or Al.

4. A method of preparing a hydroiodic acid modified tin-lead mixed perovskite solar cell as claimed in any one of claims 1 to 3, comprising the steps of:

s1 etching and ultrasonically cleaning the transparent electrode;

s2 preparing a hole transport layer on the transparent electrode processed at step S1;

s3 preparing a tin-lead mixed perovskite layer on the hole transport layer prepared in step S2;

s4 preparing an electron transport layer on the tin-lead mixed perovskite layer prepared in the step S3 using a thermal evaporation method;

s5 preparing an electron blocking layer on the electron transport layer prepared in the step S4 using a thermal evaporation method;

s6 a counter electrode was prepared on the electron blocking layer prepared at step S5 using a thermal evaporation method.

5. The method for preparing the hydroiodic acid modified tin-lead mixed perovskite solar cell according to claim 4, wherein the step S3 is to perform ozone treatment on the transparent electrode treated in the step S2, then dropwise add a tin-lead mixed perovskite precursor solution to which an inorganic hydroiodic acid solution is added to one surface of the transparent electrode on which the hole transport layer is deposited, spin-coat the transparent electrode at a spin-coating speed of 3000-5000 r/m for 30-60S, dropwise add chlorobenzene on the surface of the transparent electrode before 10-15S after the spin-coating is finished, and anneal the transparent electrode at 100 ℃ for 3-5 min after the spin-coating is finished, wherein the tin-lead mixed perovskite layer is deposited on the hole transport layer of the transparent electrode.

6. The method for preparing the hydroiodic acid modified tin-lead mixed perovskite solar cell according to claim 5, wherein the volume ratio of the tin-lead mixed perovskite precursor solution to chlorobenzene is (4-5) to (6-7).

7. The method of making a hydroiodic acid modified tin-lead mixed perovskite solar cell as claimed in claim 5, wherein the tin-lead mixed perovskite precursor solution is prepared by:

a1 mixing SnI₂、FAI、SnF₂Mixing the powder according to the molar ratio of (1-2): 1-2 to obtain a powder mixture, mixing the anhydrous DMSO and the anhydrous DMF according to the volume ratio of (1-2): 2 to obtain a mixed solution, mixing the powder mixture and the mixed solution according to the mass ratio of (1-2): 2, and heating the mixture while stirring to obtain FASnI₃A perovskite precursor solution;

a2 mixing PbI₂、MAI、Pb(SCN)₂Mixing the powders according to the molar ratio of (1-2) to obtain a powder mixture, mixing anhydrous DMSO and anhydrous DMF according to the volume ratio of (1-2) to (9) to obtain a mixed solution, mixing the powder mixture and the mixed solution according to the mass ratio of (1-2) to (2), and heating the mixed solution while stirring to obtain MAPBBr₃A perovskite precursor solution;

a3 preparation of FASnI from step A1₃Perovskite precursor solution and MAPbBr prepared in step A2₃The perovskite precursor solution is prepared from the following components in a molar ratio of (5-6): 4, adding an inorganic hydriodic acid solution to obtain a precursor solution of the tin-lead mixed perovskite.

8. The method for preparing the hydriodic acid-modified tin-lead mixed perovskite solar cell according to claim 7, wherein the concentration of the inorganic hydriodic acid solution is 95-99.8%, and the inorganic hydriodic acid solution and FASnI are₃Perovskite precursor solution and MAPbBr₃The perovskite precursor solution is mixed according to the molar ratio (1-2) to 10: 10.

9. The method for preparing a hydroiodic acid modified tin-lead mixed perovskite solar cell according to claim 7, wherein the temperature of 50-60 ℃ is heated for 1-2 h while stirring in step A1, and/or the temperature of 50-60 ℃ is heated for 1-2 h while stirring in step A2.

Technical Field

The invention relates to the field of perovskite solar cells, in particular to a hydroiodic acid modified tin-lead mixed perovskite solar cell and a preparation method thereof.

Background

In recent years, lead-based perovskite solar cells are developed rapidly, and can show high photoelectric conversion efficiency and stability, but lead has high toxicity, so that environmental problems can be caused in the processes of preparation, utilization and post-treatment, and the lead-based perovskite solar cells are difficult to popularize and apply. The tin-lead mixed perovskite solar cell combines the advantages of the tin-based perovskite solar cell and the lead-based perovskite solar cell, not only improves the photoelectric conversion efficiency and stability, but also reduces the toxicity of the material, and has great development potential.

Although research on tin-lead mixed perovskite has been advanced remarkably, the perovskite material has certain gap compared with pure lead perovskite material, and the photoelectric conversion efficiency and stability of the perovskite material still need to be improved, and the problems are mainly caused by factors such as energy level mismatch, easy oxidation of tin, interface defects and the like. At present, some technologies for improving battery performance by introducing additives into a tin-lead mixed perovskite precursor solution have appeared, for example, the chinese patent "a lead-tin blended perovskite layer and a preparation method and application thereof" (application No. 201910886038.6, application published: 2019.12.10) discloses that a metal reducing agent is added into a lead-tin blended perovskite precursor solution to reduce the defect density of perovskite; chinese patent 'a lead-tin blended perovskite thin film and a preparation method and application thereof' (application number: 202011064738.6, application publication date: 2021.02.09) discloses that a zwitter-ion reducing agent is added into a perovskite precursor solution to passivate the defects of the perovskite thin film, and the crystallization of the lead-tin blended perovskite is regulated and controlled at the same time to improve the uniformity of the perovskite thin film.

Disclosure of Invention

The invention aims to overcome at least one defect (deficiency) of the prior art and provides a hydriodic acid modified tin-lead mixed perovskite solar cell and a preparation method thereof, which can inhibit tin ion oxidation in a tin-lead mixed perovskite layer, reduce the defect density of a perovskite thin film, improve the crystallization of the perovskite thin film and improve the device stability and the photoelectric conversion efficiency of the perovskite solar cell.

The technical scheme adopted by the invention is that the hydriodic acid modified tin-lead mixed perovskite solar cell comprises a transparent electrode, a hole transport layer, a tin-lead mixed perovskite layer, an electron transport layer, an electron barrier layer and an electrode from top to bottom in sequence, wherein the tin-lead mixed perovskite layer is prepared by adding an inorganic hydriodic acid solution into a tin-lead mixed perovskite precursor solution.

In the technical scheme, the inorganic hydriodic acid solution is introduced into the tin-lead mixed perovskite precursor solution, and different from the introduction of other organic hydriodic acid salts or iodides into the tin-lead perovskite precursor solution, the inorganic hydriodic acid can improve tin-lead mixed perovskite thin films in various aspects, not only can be used as a reducing agent in the tin-lead mixed perovskite precursor solution to inhibit tin ion oxidation and improve the quality of the thin films, but also can be used as an additive to improve the photoelectric conversion efficiency of devices, and overcomes the defect that other additives can only optimize one performance of the perovskite thin films, so that the introduction of hydriodic acid has greater advantages.

In the tin-lead mixed perovskite precursor solution, inorganic hydriodic acid is used as a reducing agent in the solution, and the inorganic hydriodic acid and Sn are mixed⁴⁺The reaction mechanism is I^-+Sn⁴⁺＝Sn²⁺+I₂Therefore, inorganic hydriodic acid can oxidize Sn in the process of preparing devices⁴⁺Reduction to Sn²⁺So as to inhibit the oxidation of tin ions and reduce the defect density of the perovskite thin film; in the preparation process, hydrogen ions and iodide ions containing lone pair electrons form chemical complexes with lead ions and tin ions in perovskite, the crystallization of the perovskite film can be regulated and controlled to improve the film forming quality, on one hand, the crystal boundary is passivated, the dark current is reduced, on the other hand, the crystallinity and the coverage rate of the perovskite film are improved, the formation of pinholes in the perovskite film is reduced, the compounding of charges in a device is inhibited, and the extraction performance of the charges of the device is improved, so that the photoelectric conversion efficiency of the tin-lead mixed perovskite solar cell is improved; in addition, the introduction of hydrogen ions can effectively passivate deep level trap states such as Pb-I inversion defect and Pb atoms with insufficient coordination, so that non-radiative recombination is reduced, and the photoelectric conversion efficiency is improved; the introduction of hydroiodic acid can improve the photoelectric conversion efficiency and stability of the device, so that the content of lead in the precursor solution of the tin-lead mixed perovskite can be reduced, and the toxicity of the tin-lead mixed perovskite material can be further reduced.

Further, the content of inorganic hydroiodic acid in the tin-lead mixed perovskite precursor solution is 5-10 mu L.

Preferably, the content of inorganic hydroiodic acid in the tin-lead mixed perovskite precursor solution is 5 μ L.

In the technical scheme, a certain amount of inorganic hydriodic acid is added into the tin-lead mixed perovskite precursor solution, so that the reduction effect of the inorganic hydriodic acid on tin ions and the passivation effect on film defects are ensured, the quality of the perovskite film is improved, and the influence on the performance of a device caused by the excessive addition of the inorganic hydriodic acid is avoided.

Further, the material of the transparent electrode is a base material doped with one or more mixtures of ITO, FTO, AZO or ATO;

the hole transport layer is made of one or a mixture of PEDOT, PSS, PTAA or Poly-TPD;

the tin-lead mixtureThe perovskite layer is made of MASn_xPb_1-xI₃、FASn_xPb_1-x I₃、MA_xFA_1-x Sn_yPb_1-yI3、 FA_bCs_1-bSn_xPb₁-xI₃、(FASnI₃)_1-x(MAPbI₃)_xOne or more mixtures of (a);

the material of the electron transport layer is C₆₀Or PC₆₁One or two mixtures of BM;

the electron blocking layer is one or a mixture of two of BCP or ZnO;

the counter electrode is made of one or a mixture of Au, Ag or Al.

Preferably, the material of the transparent electrode is a doped Indium Tin Oxide (ITO) substrate material; the hole transport layer is made of PEDOT (Poly ethylene glycol ether ketone) PSS (Poly ethylene glycol ether ketone); the tin-lead mixed perovskite layer is made of (FASnI)₃)_1-x(MAPbI₃)_x(ii) a The material of the electron transport layer is C₆₀(ii) a The electron blocking layer is made of BCP; the counter electrode is made of Ag.

The invention also provides a preparation method of the hydroiodic acid modified tin-lead mixed perovskite solar cell, which comprises the following steps:

s1 etching and ultrasonically cleaning the transparent electrode;

s2 preparing a hole transport layer on the transparent electrode processed at step S1;

s3 preparing a tin-lead mixed perovskite layer on the hole transport layer prepared in step S2;

s4 preparing an electron transport layer on the tin-lead mixed perovskite layer prepared in the step S3 using a thermal evaporation method;

s5 preparing an electron blocking layer on the electron transport layer prepared in the step S4 using a thermal evaporation method;

s6 a counter electrode was prepared on the electron blocking layer prepared at step S5 using a thermal evaporation method.

Further, the step S1 is: and after etching the transparent electrode, immersing the transparent electrode in isopropanol, carrying out ultrasonic cleaning for 20-30 min, taking out, adding a detergent and deionized water, carrying out ultrasonic cleaning for 20-30 min, taking out, adding deionized water, carrying out ultrasonic cleaning for 20-30 min, repeatedly cleaning for 2-3 times, and drying for 12 h.

Preferably, the ultrasonic power of the ultrasonic cleaning is 40-60%, and the ultrasonic temperature is 20-25 ℃.

Preferably, in step S1, a specific position of the transparent electrode is etched, specifically, areas with the same width are etched on both sides of the transparent electrode, so as to distinguish the conductive surface from the non-conductive surface in the subsequent spin coating process, thereby avoiding misoperation.

Further, in the step S2, the transparent electrode processed in the step S1 is treated with ozone, then a solution containing a hole transport layer material is dropped on the surface of the transparent electrode, spin-coating is performed at a spin-coating speed of 2000 to 4000r/m for 20 to 30 seconds, and then annealing is performed at 150 to 175 ℃ for 10 to 15min, so that the hole transport layer is deposited on the transparent electrode.

Preferably, 40-50. mu.L of a PEDOT: PSS solution is added dropwise to the surface of the transparent electrode in step S2.

Further, in the step S3, the transparent electrode processed in the step S2 is subjected to ozone treatment, then a tin-lead mixed perovskite precursor solution added with an inorganic hydroiodic acid solution is dripped to one surface of the transparent electrode on which the hole transport layer is deposited, spin coating is performed at a spin coating speed of 3000-5000 r/m for 30-60S, chlorobenzene is dripped on the surface of the transparent electrode before 10-15S is completed, after the spin coating is completed, the transparent electrode is placed at 100 ℃ for annealing for 3-5 min, and the tin-lead mixed perovskite layer is deposited on the hole transport layer of the transparent electrode.

Preferably, the volume ratio of the tin-lead mixed perovskite precursor solution to chlorobenzene is (4-5) to (6-7).

Preferably, 50-60 mu L of the tin-lead mixed perovskite precursor solution is dripped to one surface of the transparent electrode deposition hole transport layer; and dripping 60-70 mu L of chlorobenzene on the surface of the transparent electrode 5-8 s before the spin coating is finished.

Still further, the tin-lead mixed perovskite precursor solution is prepared by the following method:

a1 mixing SnI₂、FAI、SnF₂Mixing the powder according to the molar ratio of (1-2) to obtain a powder mixture, and mixing the anhydrous DMSO and the anhydrous DMF according to the volume ratio of (1-2): 2, mixing to obtain a mixed solution, wherein the powder mixture and the mixed solution are mixed according to the mass ratio (1-2): 2 mixing, stirring and heating to obtain FASnI₃A perovskite precursor solution;

a2 mixing PbI₂、MAI、Pb(SCN)₂Mixing the powders according to the molar ratio of (1-2) to obtain a powder mixture, mixing anhydrous DMSO and anhydrous DMF according to the volume ratio of (1-2) to (9) to obtain a mixed solution, mixing the powder mixture and the mixed solution according to the mass ratio of (1-2) to (2), and heating the mixed solution while stirring to obtain MAPBBr₃A perovskite precursor solution;

a3 preparation of FASnI from step A1₃Perovskite precursor solution and MAPbBr prepared in step A2₃And mixing the perovskite precursor solution according to the molar ratio of (5-6) to (4), and adding an inorganic hydriodic acid solution to obtain the tin-lead mixed perovskite precursor solution.

Preferably, the concentration of the inorganic hydriodic acid solution is the inorganic hydriodic acid solution, FASnI₃Perovskite precursor solution and MAPbBr₃The perovskite precursor solution is prepared by mixing the following components in a molar ratio of 1: 1 and mixing.

Preferably, the SnI₂0.2200-0.2232 g of FAI, 0.1000-0.1032 g of SnF₂The addition amount is 0.0090-0.0093 g, PbI₂The addition amount is 0.1800-0.1844 g, the addition amount of MAI is 0.0630-0.6360, Pb (SCN)₂The amount of the additive is 0.0040-0.0045 g.

Further, in the step S4, the electron transport layer is thermally deposited under vacuum after one electrode of the transparent electrode is scraped off by spin coating, the deposition rate is 0.2 to 0.4 a/S, and when the thickness of the electrode is up to 20 to 30nm, the deposition is stopped to obtain the electron transport layer.

Preferably, in the step S4, after the transparent electrode is transferred to a vacuum thermal evaporation apparatus and placed in a mask plate to scrape off one electrode of spin coating, the transparent electrode and an appropriate amount of C60 powder are placed in an evaporation machine together, evaporation is started after vacuum pumping is performed to 106Torr or less, and evaporation is stopped when the C60 is evaporated to reach a thickness of 20 to 30nm, that is, the electron transport layer deposited on the tin-lead mixed perovskite layer is obtained.

And step S5, the transparent electrode and the BCP powder after the electron transport layer is prepared in step S4 are placed in an evaporation machine for thermal evaporation, the evaporation machine is vacuumized to 106Torr or less, evaporation is started at an evaporation rate of 0.2-0.4 a/S, and the evaporation is stopped when the thickness reaches 7nm, so that the electron barrier layer deposited on the electron transport layer of the transparent electrode is obtained.

And step S6, performing thermal evaporation on the transparent electrode after the electron blocking layer is prepared in step S5 under vacuum, wherein the evaporation rate is 0.2-0.4 a/S, and when the thickness of the counter electrode reaches 80-100 nm, stopping evaporation, and cooling to obtain the counter electrode deposited on the electron blocking layer.

Preferably, in the step S6, the transparent electrode and a proper amount of Ag particles are put into a deposition machine, and deposition is started after vacuum pumping is performed until the thickness of the electrode reaches 80 to 100nm, and the deposition is stopped, and the hydriodic acid modified tin-lead mixed perovskite solar cell is obtained after cooling for 1 hour.

Preferably, the heating is carried out at a temperature of 50-60 ℃ for 1-2 h while stirring in the step A1, and/or the heating is carried out at a temperature of 50-60 ℃ for 1-2 h while stirring in the step A2.

In the technical scheme, inorganic hydriodic acid is introduced into a tin-lead mixed perovskite precursor solution, so that the oxidation of tin ions can be inhibited in the preparation process to reduce the defect density of a perovskite thin film, deep level trap states of Pb-I reverse defects, Pb atoms with insufficient coordination and the like are effectively passivated to reduce non-radiative recombination, the crystallinity of the tin-lead mixed perovskite crystal is improved, dark current is reduced by passivating a crystal boundary, the film forming quality of the perovskite thin film is improved, needle holes in the perovskite thin film are fewer, the thin film coverage rate is improved, and the stability and the photoelectric conversion efficiency of the tin-lead mixed perovskite solar cell are improved.

Compared with the prior art, the invention has the beneficial effects that:

(1) according to the invention, the tin-lead mixed perovskite layer is prepared by adding the inorganic hydriodic acid solution into the tin-lead mixed perovskite precursor solution, the inorganic hydriodic acid not only serves as a reducing agent to inhibit the oxidation of tin ions so as to reduce the defect density of the perovskite film, but also can form a chemical complex with lead ions and tin ions, so that the film forming quality of the perovskite layer is improved, the defect that other perovskite material additives can only optimize one property of the tin-lead mixed perovskite material is overcome, the stability and the photoelectric conversion efficiency of a device can be improved, the addition amount of the additives can be reduced, and the influence of excessive additives on the device performance is avoided;

(2) after the inorganic hydriodic acid is introduced, the lead content in the perovskite precursor solution can be reduced to reduce the toxicity of the tin-lead mixed perovskite layer, so that the device has higher photoelectric conversion efficiency, and the problem of higher toxicity of the conventional tin-lead mixed perovskite solar cell is solved;

(3) the electron blocking layer is arranged between the electron transmission layer and the counter electrode, so that the electron transmission layer can be prevented from diffusing to the counter electrode in the thermal evaporation process when the counter electrode is prepared, the quality of the electron transmission layer is ensured, and the charge transmission efficiency is improved;

(4) the preparation method of the invention adopts the thermal evaporation method to sequentially prepare the electron transmission layer, the electron barrier layer and the counter electrode on the transparent electrode, the preparation process is reliable and efficient, and the prepared film is uniform and compact, can be applied to optical devices and has wide application prospect.

Drawings

Fig. 1 is a schematic structural diagram of a hydriodic acid modified tin-lead mixed perovskite solar cell of the invention.

FIG. 2 is a schematic diagram of the etching region of the transparent electrode according to the present invention.

Fig. 3 is a graph showing the results of the photovoltaic efficiency test of the cells of examples 1 and 2 and comparative examples 1 and 2.

Fig. 4 is a scanning electron microscope image of the tin-lead mixed perovskite layer of example 1.

Fig. 5 is a scanning electron microscope image of the tin-lead mixed perovskite layer of example 2.

Fig. 6 is a scanning electron microscope image of the tin-lead mixed perovskite layer of comparative example 1.

Fig. 7 is a scanning electron microscope image of the tin-lead mixed perovskite layer of comparative example 2.

In the drawings are labeled: a transparent electrode 100; etching the region 110; a non-etched region 120; a hole transport layer 200; a perovskite layer 300; an electron transport layer 400; an electron blocking layer 500; the counter electrode 600.

Detailed Description

The drawings are only for purposes of illustration and are not to be construed as limiting the invention. For a better understanding of the following embodiments, certain features of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.

The experimental procedures used in the following examples are all conventional procedures unless otherwise specified.

Materials, reagents and the like used in the following examples are commercially available unless otherwise specified.

In the following embodiments, the material of the transparent electrode is a doped ITO substrate, and the etching regions 110 on both sides of the non-etching region 120 are etched according to fig. 2; the hole transport layer is made of PEDOT (Poly ethylene glycol ether ketone) PSS (Poly ethylene glycol ether ketone); the tin-lead mixed perovskite layer is made of (FASnI)₃)_1-x(MAPbI₃)_x(ii) a The material of the electron transport layer is C₆₀(ii) a The electron blocking layer is made of BCP; the counter electrode is made of Ag.

Example 1

As shown in fig. 1, the present embodiment provides a hydriodic acid-modified tin-lead mixed perovskite solar cell, which sequentially includes, from top to bottom, a transparent electrode, a hole transport layer, a tin-lead mixed perovskite layer, an electron transport layer, an electron blocking layer, and an opposite electrode, where the tin-lead mixed perovskite layer is prepared by adding an inorganic hydriodic acid solution to a tin-lead mixed perovskite precursor solution.

The tin-lead mixed perovskite solar cell of the embodiment is prepared by the following method, and the specific steps are as follows:

s1 etching and ultrasonic cleaning of the transparent electrode: etching the transparent electrode by using a diamond pen according to the etching area schematic diagram of fig. 2, placing the transparent electrode on a polytetrafluoroethylene cleaning frame, then placing the etched transparent electrode and the polytetrafluoroethylene cleaning frame into a beaker, pouring isopropanol into the beaker until the transparent electrode is immersed, carrying out ultrasonic cleaning for 30min at the temperature of 20-25 ℃ by using 40-60% of ultrasonic power, then pouring out waste liquid, then adding detergent and deionized water, carrying out ultrasonic cleaning for 30min at the same ultrasonic power and temperature, then pouring out the waste liquid, adding deionized water, carrying out ultrasonic cleaning for 30min at the same ultrasonic power and temperature, repeatedly cleaning for 3 times, and then placing the cleaned transparent electrode in a drying oven for drying for 12 h;

s2 preparation of hole transport layer: the transparent electrode treated in the step S1 was subjected to ozone treatment and the PEDOT solution was filtered with a filter head to prepare a PEDOT/PSS solution for a hole transport layer, the transparent electrode treated with ozone was placed on a spin coater, the spin speed of the spin coater was set to 4000r/m, the spin time was set to 30S, and the spin acceleration was set to 1000r/m²Dripping 40 mu L of PEDOT solution on the surface of the transparent electrode, starting spin coating, placing the transparent electrode on a heating table at 150 ℃ for annealing for 15min after the spin coating is finished, and depositing the hole transport layer on the transparent electrode;

s3 preparing a tin-lead mixed perovskite layer: subjecting the transparent electrode treated in step S2 to ozone treatment for 30min, placing on a spin coater in a glove box filled with Ar gas, setting the spin speed of the spin coater to 5000r/m, the spin time to 60S, and the spin acceleration to 1000r/m²Sucking 50 mu L of perovskite precursor solution by using a liquid transfer gun and dripping the solution on one surface of a transparent electrode deposition hole transport layer, starting spin coating, sucking 70 mu L of chlorobenzene by using the liquid transfer gun and dripping the chlorobenzene on the surface of the transparent electrode 15s before the spin coating is finished, and after the spin coating is finished, placing the transparent electrode on a heating table at 100 ℃ and annealing for 5min, wherein the perovskite layer is deposited on the hole transport layer of the transparent electrode;

s4 preparing an electron transport layer: transferring the transparent electrode into a vacuum thermal evaporation device, placing the transparent electrode in a mask plate, scraping off one electrode in spin coating, and then placing the transparent electrode and the C₆₀Placing the powder in a deposition machine for thermal deposition, vacuumizing the deposition machine to below 106Torr, and starting to perform thermal depositionAt a vapor deposition rate of (C)₆₀Stopping evaporation until the thickness reaches 20nm to obtain an electron transport layer deposited on the tin-lead mixed perovskite layer;

s5 preparing an electron blocking layer: placing the transparent electrode and BCP powder in a vapor deposition machine for thermal vapor deposition, and starting to vacuumize the vapor deposition machine to below 106TorrThe evaporation rate is used for evaporation, and when the thickness reaches 7nm, the evaporation is stopped, so that the electron barrier layer deposited on the electron transmission layer of the transparent electrode is obtained;

s6 preparing a counter electrode: putting the transparent electrode and a proper amount of Ag particles into an evaporation machine for thermal evaporation, and vacuumizing the evaporation machine to be below 106Torr to startThe evaporation rate is adopted for evaporation, when the electrode is evaporated to reach the thickness of 100nm, the evaporation is stopped, and the hydriodic acid modified tin-lead mixed perovskite solar cell is obtained after cooling for 1 h.

In this embodiment, the tin-lead mixed perovskite precursor solution of step S3 is prepared by the following method, which specifically includes the steps of:

a1 mixing 0.223g SnI₂Powder, 0.103g FAI powder, 0.009g SnF₂Mixing the powders to obtain a powder mixture, and mixing anhydrous DMSO and anhydrous DMF in a volume ratio of 1: 4 to obtain a mixed solution, taking 0.5ml of the mixed solution to be uniformly mixed with the powder mixture, and placing the mixed solution at the temperature of 50 ℃ while stirring and heating for 2 hours to obtain FASnI₃A perovskite precursor solution;

a2 mixing 0.184g PbI₂Powder, 0.063g MAI powder, 0.004g Pb (SCN)₂Mixing the powders to obtain a powder mixture, and mixing anhydrous DMSO and anhydrous DMF in a volume ratio of 1: 9 to obtain a mixed solution, uniformly mixing 0.5ml of the mixed solution with the powder mixture, and heating the mixed solution at the temperature of 50 ℃ for 2 hours while stirring to obtain MAPbI₃A perovskite precursor solution;

a3 preparation of FASnI from step A1₃Perovskite precursor solution and MAPbBr prepared in step A2₃Mixing the perovskite precursor solution according to the mol ratio of 6:4, heating the mixture for 2 hours at 50 ℃ while stirring, adding 10 mu L of hydriodic acid solution with the concentration of 99.8 percent, uniformly mixing, and filtering the perovskite precursor solution through a filter head to obtain the perovskite precursor solution.

Example 2

As shown in fig. 1, this embodiment provides a hydriodic acid-modified tin-lead mixed perovskite solar cell, which includes, from top to bottom, a transparent electrode, a hole transport layer, a tin-lead mixed perovskite layer, an electron transport layer, an electron blocking layer, and a counter electrode, in order, where the tin-lead mixed perovskite layer is prepared by adding an inorganic hydriodic acid solution to a tin-lead mixed perovskite precursor solution, and is substantially the same as in example 1 except that the inorganic hydriodic acid solution is added to the tin-lead mixed perovskite precursor solution in a different amount. In this embodiment, the tin-lead mixed perovskite precursor solution of step S3 is prepared by the following method, which specifically includes the following steps:

a1 mixing 0.223g SnI₂Powder, 0.103g FAI powder, 0.009g SnF₂Mixing the powders to obtain a powder mixture, and mixing anhydrous DMSO and anhydrous DMF in a volume ratio of 1: 4 to obtain a mixed solution, taking 0.5ml of the mixed solution to be uniformly mixed with the powder mixture, and placing the mixed solution at the temperature of 50 ℃ while stirring and heating for 2 hours to obtain FASnI₃A perovskite precursor solution;

a2 mixing 0.184g PbI₂Powder, 0.063g MAI powder, 0.004g Pb (SCN)₂Mixing the powders to obtain a powder mixture, and mixing anhydrous DMSO and anhydrous DMF in a volume ratio of 1: 9 to obtain a mixed solution, uniformly mixing 0.5ml of the mixed solution with the powder mixture, and heating the mixed solution at the temperature of 50 ℃ for 2 hours under stirring to obtain MAPBI3 perovskite precursor solution;

a3 preparation of FASnI from step A1₃Perovskite precursor solution and MAPbBr prepared in step A2₃Mixing the perovskite precursor solution according to a molar ratio of 6:4, heating the mixture at 50 ℃ for 2 hours while stirring, adding 5 mu L of 99.8% hydriodic acid solution, uniformly mixing, and filtering the perovskite precursor solution through a filter head to obtain the perovskite precursor solution.

Comparative example 1

As shown in fig. 1, the present comparative example provides a hydriodic acid-modified tin-lead mixed perovskite solar cell including a transparent electrode, a hole transport layer, a tin-lead mixed perovskite layer, an electron transport layer, an electron blocking layer, and a counter electrode in this order from top to bottom, which is substantially the same as examples 1 and 2 except that in the present comparative example, an inorganic hydriodic acid solution is not added to the tin-lead mixed perovskite layer.

Comparative example 2

As shown in fig. 1, the present comparative example provides a hydriodic acid-modified tin-lead mixed perovskite solar cell, which comprises a transparent electrode, a hole transport layer, a tin-lead mixed perovskite layer, an electron transport layer, an electron blocking layer, and a counter electrode in this order from top to bottom, and is substantially the same as examples 1 and 2, except that in the present comparative example, the tin-lead mixed perovskite layer is prepared after being added to a tin-lead mixed perovskite precursor solution.

In the present comparative example, the tin-lead mixed perovskite precursor solution of step S3 was prepared by the following method, including the specific steps:

a1 mixing 0.223g SnI₂Powder, 0.103g FAI powder, 0.009g SnF₂Mixing the powders to obtain a powder mixture, and mixing anhydrous DMSO and anhydrous DMF in a volume ratio of 1: 4 to obtain a mixed solution, taking 0.5ml of the mixed solution to be uniformly mixed with the powder mixture, and placing the mixed solution at the temperature of 50 ℃ while stirring and heating for 2 hours to obtain FASnI₃A perovskite precursor solution;

a2 mixing 0.184g PbI₂Powder, 0.063g MAI powder, 0.004g Pb (SCN)₂Mixing the powders to obtain a powder mixture, and mixingAnhydrous DMSO and anhydrous DMF in a volume ratio of 1: 9, mixing to obtain a mixed solution, uniformly mixing 0.5ml of the mixed solution with the powder mixture, and placing the mixed solution at 50 ℃ while stirring and heating for 2 hours to obtain a MAPbI3 perovskite precursor solution;

a3 preparation of FASnI from step A1₃Perovskite precursor solution and MAPbBr prepared in step A2₃Mixing the perovskite precursor solution according to a molar ratio of 6:4, heating the mixture at 50 ℃ for 2 hours while stirring, adding 5 mu L of 99.8% iodic acid, uniformly mixing, and filtering the perovskite precursor solution through a filter head to obtain the perovskite precursor solution.

The solar cells prepared in examples 1 and 2 and comparative examples 1 and 2 were placed under simulated sunlight and measured for their performance using a J-V curve, which is a current density-voltage characteristic curve, using a test light source of AM1.5G, 100mW cm^-2And (3) simulating sunlight of a xenon lamp, placing the solar cell prepared in the examples 1 and 2 and the comparative examples 1 and 2 under a test light source for irradiating for 3-5 min, and collecting data through a digital source table. Important performance parameters that can be obtained by this test are: short-circuit current density Jsc, open-circuit voltage Voc, fill factor FF and photoelectric conversion efficiency PCE.

The test results are shown in fig. 3, wherein fig. 3(a) and fig. 3(b) are the test results of the solar cells of examples 1 and 2, and fig. 3(c) and fig. 3(d) are the test results of comparative examples 1 and 2, respectively, and it can be seen from the figure that the photoelectric conversion efficiency of example 1 is lower than that of example 2 because the inorganic hydroiodic acid is introduced into the solar cell film prepared under the conditions of example 2 is more compact and uniform, the photoelectric conversion efficiency is higher, and the stability is better, when the other preparation conditions are the same, because the amount of the inorganic hydroiodic acid introduced into the solar cell film is different from that of example 1 and example 2; compared with the examples 1 and 2, the photoelectric conversion efficiency of the comparative example 1 is the lowest, because the comparative example 1 does not introduce inorganic hydriodic acid into a perovskite precursor solution, and under the condition of the same other preparation conditions, the examples 1 and 2 introduce the inorganic hydriodic acid into the perovskite precursor solution, and the inorganic hydriodic acid not only serves as a reducing agent to inhibit the oxidation of tin ions and improve the stability of the tin-lead mixed perovskite solar cell, but also serves as an additive to passivate an interface, adjust the crystallization of perovskite and improve the film forming quality of the perovskite solar cell, so that the photoelectric conversion efficiency of the tin-lead mixed perovskite solar cell is improved; the photoelectric conversion efficiency of comparative example 2 is higher than that of comparative example 1, but lower than that of examples 1 and 2 because it can only optimize the crystal structure of the tin-lead mixed perovskite material, cannot suppress oxidation of tin ions, and cannot improve other properties of the tin-lead mixed perovskite material.

The shapes of the tin-lead mixed perovskite layers prepared in steps S3 of examples 1 and 2 and comparative examples 1 and 2 were observed using a scanning electron microscope, and scanning electron microscope images thereof are shown in fig. 4 to 7, wherein fig. 4 is a scanning electron microscope image of the tin-lead mixed perovskite layer prepared in example 1, fig. 5 is a scanning electron microscope image of the tin-lead mixed perovskite layer prepared in example 2, fig. 6 is a scanning electron microscope image of the tin-lead mixed perovskite layer prepared in comparative example 1, and fig. 7 is a scanning electron microscope image of the tin-lead mixed perovskite layer prepared in comparative example 2. As shown in fig. 6, the tin-lead mixed perovskite layer prepared in comparative example 1 has the most defects because inorganic hydroiodic acid is not introduced into the tin-lead mixed perovskite precursor solution, and tin ions are oxidized during the preparation process, resulting in poor film formation quality; as shown in fig. 4 and 5, the tin-lead mixed perovskite layer prepared in example 1 has fewer defects than that prepared in comparative example 1, but more defects than that prepared in example 2, because although the inorganic hydroiodic acid introduced in example 1 can inhibit the oxidation of tin ions, the added amount is too large, which affects the performance of the device, and the inorganic hydroiodic acid introduced in example 2 can be used as a reducing agent and an additive in the preparation of the tin-lead mixed perovskite layer to improve the stability and quality of the perovskite thin film, thereby improving the photoelectric conversion efficiency of the device; referring to fig. 7, the iodic acid which can not inhibit the oxidation of tin ions is introduced into comparative example 2, so that the prepared tin-lead mixed perovskite layer still has more defects.

It should be understood that the above-mentioned embodiments of the present invention are only examples for clearly illustrating the technical solutions of the present invention, and are not intended to limit the specific embodiments of the present invention. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention claims should be included in the protection scope of the present invention claims.