Method for synthesizing perovskite precursor solution of formamidine-based ionic liquid, battery device, and solar cell

Abstract

Disclosed in embodiments of the present invention are a method for synthesizing a perovskite precursor solution of a formamidine-based ionic liquid, a battery device, and a solar cell. The method comprises: respectively adding an organic sodium salt and formamidine hydrochloride to ethanol, and stirring and dissolving same to obtain a formamidine hydrochloride solution and a sodium alkyl carboxylate solution; dropwise adding the formamidine hydrochloride solution to the sodium alkyl carboxylate solution, stirring the mixed solution at 25-60°C, and reacting same for 24-36 h; filtering the reacted mixed solution, extracting a filtrate, carrying out rotary evaporation on an obtained primary filtrate to remove an ethanol solvent, and using an organic solvent to carry out oscillating washing for 25-35 min; carrying out secondary filtration on a washed solution, extracting a filtrate, and carrying out rotary evaporation an obtained secondary filtrate to remove an organic solvent, so as to obtain an organic acid formamidine ionic liquid; and dissolving lead iodide and formamidine hydroiodide in the organic acid formamidine ionic liquid, and carrying out reaction at 40-80°C for at least 5 h to obtain a perovskite precursor solution of a formamidine-based ionic liquid. The method solves the problem of poor phase stability of FAPbI3 perovskite in humidity environments.

Description

Synthesis method of perovskite precursor solution of formamidine-based ionic liquid, battery device and solar cell Technical Field

[0001] The present invention belongs to the technical field of photoelectric materials, and in particular relates to a method for synthesizing a perovskite precursor solution of a formamidine-based ionic liquid, a battery device, and a solar cell. Background Art

[0002] Ionic liquids are a type of salt composed of cations and anions that is liquid at room temperature. They are stable, have low volatility, and have a strong solubility for certain inorganic metal halides. At the same time, ionic liquids also have excellent designability and can meet various requirements through the design of anions and cations.

[0003] Organic-inorganic hybrid perovskites, direct-bandgap semiconductors with ionic properties, have garnered extensive research attention due to their exceptional optoelectronic properties and solution-based fabrication. With the continuous optimization of perovskites and related materials, the photoelectric conversion efficiency of perovskite cells has rapidly increased, reaching a current globally certified efficiency of 25.8%, comparable to silicon-based perovskite solar cells.

[0004] The greatest advantage of perovskite solar cells is their solution processing. However, the choice of solvent is limited by lead halide salts, which are either minimally soluble or completely in most solvents used in large-scale deposition techniques. Furthermore, during the fabrication of perovskite solar cells, the solvent is crucial for controlling perovskite crystallization and growth. However, efficient perovskite solar cells are currently fabricated using solution techniques using high-boiling-point, polar, and aprotic solvents such as DMF, DMSO, and GBL. Most of these solvents are highly toxic and require strict storage management, making them prone to safety hazards. Furthermore, most current high-efficiency perovskite solar cells utilize antisolvent techniques, which often use highly toxic and volatile organic solvents such as chlorobenzene, ether, and toluene. Most importantly, antisolvent technology is difficult to control during the perovskite film fabrication process, with a narrow time window for control. Consequently, the reproducibility of high-quality perovskite films produced using antisolvent techniques is poor, particularly between different research groups and even between individuals within the same research group. Since the antisolvent induces crystallization by evaporation during the preparation process, the preparation environment and atmosphere are also crucial. Therefore, solvent handling and toxicological issues are great challenges for the commercial development of perovskite solar cells.

[0005] Recently, ionic liquids, such as methylamine formate (MAFa), methylamine acetate (MAAc), and methylamine propionate (MAPa), have shown great advantages as solvents in perovskite solar cells. However, methylamine-based ionic liquids can affect the composition and structure of the crystal during the preparation of non-methylamine-based perovskite solar cells. In particular, in the preparation of the phase-transition-prone FAPbI3 perovskite, they can cause a blue shift in the band gap, thus affecting performance.

[0006] Summary of the Invention

[0007] An embodiment of the present invention provides a method for synthesizing a perovskite precursor solution of a formamidine-based ionic liquid, comprising:

[0008] Adding organic acid sodium salt and formamidine hydrochloride into ethanol respectively, stirring and dissolving, to obtain formamidine hydrochloride solution and alkyl acid sodium solution;

[0009] Add the formamidine hydrochloride solution dropwise to the sodium alkylate solution, stir the mixture at 25-60°C, and react for 24-36 hours;

[0010] The reaction mixture was filtered, and the filtrate was collected. The first-stage filtrate was evaporated to remove the ethanol solvent, and then washed with an organic solvent for 25-35 minutes.

[0011] The washed solution is filtered twice, and the filtrate is taken, and the obtained secondary filtrate is subjected to rotary evaporation to remove the organic solvent to obtain an organic acid formamidine ionic liquid;

[0012] Lead iodide and formamidine hydroiodide are dissolved in an organic acid formamidine ionic liquid, and reacted at 40-80° C. for at least 5 hours to obtain a perovskite precursor solution of the formamidine-based ionic liquid.

[0013] Specifically, the molar ratio of the organic acid sodium salt to the formamidine hydrochloride is 1:1.5-2.5.

[0014] Furthermore, it also includes:

[0015] The obtained organic acid formamidine ionic liquid is added with ethanol to dissolve, and the ethanol is removed by rotary evaporation, which is repeated multiple times to obtain a pure alkyl acid formamidine ionic liquid.

[0016] Preferably, it also includes:

[0017] The molar ratio of the mixture of the organic acid sodium salt and formamidine hydrochloride to the ethanol is 1:5-8.

[0018] Specifically, the organic acid sodium salt is at least one of sodium alkylate, sodium propionate or sodium butyrate.

[0019] An embodiment of the present invention further provides a method for preparing a perovskite battery device, comprising:

[0020] Cleaning the conductive glass substrate, spin-coating an electron transport material on the conductive glass substrate, and spin-coating a perovskite precursor solution of the formamidinium-based ionic liquid prepared by the above-mentioned synthesis method on the electron transport layer of the conductive glass substrate, and annealing to form a formamidinium-based perovskite film;

[0021] A hole transport layer material is spin-coated on the formamidinium-based perovskite film to obtain a hole transport layer, and a modification layer and a metal electrode are evaporated on the hole transport layer.

[0022] Specifically, the preparation of the electron transport layer further includes:

[0023] Mixing SnO2 and deionized water in a mass ratio of 1:3-7 to obtain a SnO2 solution of electron transport layer material;

[0024] Spin-coat the SnO2 solution on the conductive substrate at 3500-4500 r / min for 20-40 seconds using a spin coater to form a film, and anneal at 120-180° C. for at least 30 minutes;

[0025] The annealed conductive substrate spin-coated with the electron transport layer is subjected to ultraviolet ozone treatment for at least 10 minutes.

[0026] Specifically, the preparation of the hole transport layer further includes:

[0027] Spiro-OMeTAD was dissolved in chlorobenzene and stirred, and an acetonitrile solution of lithium bis(trifluoromethanesulfonyl)imide and 4-tert-butylpyridine were added to form a hole transport layer material;

[0028] The hole transport layer material is spin-coated on the surface of the AgBiS2 active layer at 3500-4500 r / min for 20-40 seconds to form a film, and then oxidized in air for at least 24 hours.

[0029] Specifically, the modified layer is MoO3 with a thickness of 3-7 nm, and the metal electrode is Au or Ag with a thickness of 80-120 nm.

[0030] An embodiment of the present invention further provides a solar cell comprising the perovskite cell device described above.

[0031] The method for synthesizing a perovskite precursor solution containing a formamidine-based ionic liquid provided in an embodiment of the present invention is applied to the preparation of FAPbI3 perovskite thin films. This method is completed in air, enabling the one-step preparation of pure FAPbI3 perovskite films in air, addressing the issue of poor phase stability of FAPbI3 perovskite in humid environments. The FAPbI3 perovskite films prepared by this method exhibit uniform, dense, and component-stable crystallinity. The preparation process is low-cost, simple to operate, operates at low temperatures, and is easily scalable. This method is of great significance for the future large-scale production of high-efficiency perovskite solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0033] FIG1 is a physical diagram of an alkyl acid formamidine ionic liquid provided in an embodiment of the present invention;

[0034] FIG2 is a chemical reaction equation provided by an embodiment of the present invention;

[0035] FIG3 is a structural diagram of a perovskite device provided in an embodiment of the present invention;

[0036] FIG4 is an XRD pattern of a perovskite film provided in an embodiment of the present invention;

[0037] FIG5 is a JV curve diagram of the perovskite device in Example 1 provided in an embodiment of the present invention;

[0038] FIG6 is a JV curve diagram of the perovskite device in Example 2 provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0039] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0040] Example 1

[0041] 1. Sodium propionate and formamidine hydrochloride were added to a single-necked flask containing ethanol respectively, and stirred at room temperature for 24 hours until completely dissolved. The completely dissolved formamidine hydrochloride was added dropwise to the single-necked flask containing sodium propionate. The mixture in the single-necked flask was magnetically stirred at 25-60°C. After stirring for 24-36 hours, the reaction was stopped.

[0042] 2. The reaction solution obtained in step 1 is filtered once, and the first filtrate is evaporated to remove the ethanol solvent, and then washed with acetone or benzene for 20 to 35 minutes. The washed solution is filtered twice to remove excess solids, and the second filtrate is evaporated to remove the acetone or benzene solvent to obtain the desired propionic acid formamidine ionic liquid, as shown in Figure 1.

[0043] 3. Weigh 291.33 mg of lead iodide and 108.67 mg of formamidine hydroiodide, dissolve them in 1 ml of formamidine propionate ionic liquid solvent at a molar ratio of 1:1 and a concentration of 300-600 mg / ml. React the prepared precursor solution at 60°C for 5 hours, as shown in the reaction formula in Figure 2.

[0044] 4. Clean the ITO conductive glass in the following order: ethanol with detergent, ultrapure water with detergent, ultrapure water, acetone, and ethanol, ultrasonically for 10 minutes each, blow dry with nitrogen to obtain a clean conductive glass substrate, and treat with UV ozone for 15 minutes.

[0045] 5. Dilute 1ml of SnO2 with ultrapure water to a 2.67wt% solution. Drop 45μL of the diluted SnO2 onto the ITO substrate and spin coat it using a spin coater at 3000 rpm for 30 seconds. Anneal the SnO2-coated ITO at 150°C for 30 minutes. Place the annealed ITO substrate with the electron transport layer on a hot spin coater and preheat for 5 minutes.

[0046] 6. Take 80 μL of the perovskite precursor solution from step 3 and drop it onto the preheated ITO substrate. Spin-coat the solution and then anneal it to form a perovskite film. Spin-coat the perovskite precursor solution at 4000 rpm for 30 seconds. Anneal the solution in dry air at 150°C for 30 minutes.

[0047] 7. Weigh 73.2 mg of Spiro-MeOTAD, dissolve it in 1 ml of chlorobenzene solvent and stir to dissolve for 1 hour, then add 17.6 μL of lithium bis(trifluoromethanesulfonamide) dissolved in acetonitrile at a concentration of 520 mg / ml and stir to dissolve for 1 hour, finally add 28.8 μL of 4-tert-butylpyridine and stir to dissolve for 1 hour to obtain a hole transport layer material, and spin-coat it on the perovskite film. Spin-coat Spiro-MeOTAD at 3000 r / min for 30 seconds to form a hole transport layer, and oxidize it in air for 24 hours.

[0048] 8. Using vacuum evaporation technology, 5nm MoO3 was evaporated on the hole transport layer, and then 100nm metal electrode Ag was evaporated to obtain a perovskite solar cell device, as shown in the structure diagram of Figure 3. As shown in Figure 4, a strong black phase FAPbI3 perovskite can be obtained at 13.9°. As shown in Figures 5 and 6, under standard test conditions (AM1.5G light), the energy conversion efficiency of the battery device prepared in this example was 16.5%, the open circuit voltage was 0.976V, and the short circuit current was 26.17mA / cm 2 , the filling factor is 64.66%.

[0049] Example 2

[0050] 1. Sodium butyrate and formamidine hydrochloride were added to a single-necked flask containing ethanol respectively, and stirred at room temperature for 24 hours until completely dissolved; the completely dissolved formamidine hydrochloride was added dropwise to the single-necked flask containing sodium butyrate, and the mixture in the single-necked flask was magnetically stirred at 25-60°C. After stirring for 24-36 hours, the reaction was stopped;

[0051] 2. The obtained reaction solution is filtered once, and the first filtrate is subjected to rotary evaporation to remove the ethanol solvent, and then the solution is shaken and washed with acetone or benzene for 20 to 35 minutes. The washed solution is filtered twice to remove excess solids, and the second filtrate is subjected to rotary evaporation to remove the acetone or benzene solvent to obtain the desired butyric acid formamidine ionic liquid;

[0052] 3. Weigh 291.33 mg of lead iodide and 108.67 mg of formamidine hydroiodide, dissolve them in 1 ml of butyrate formamidine ionic liquid solvent, and react at 40°C for 6 h.

[0053] 4. Clean the ITO conductive glass in the following order: ethanol with detergent, ultrapure water with detergent, ultrapure water, acetone, and ethanol, ultrasonically for 15 minutes each, blow dry with nitrogen, and obtain a clean conductive glass substrate, and then treat with UV ozone for 20 minutes.

[0054] 5. Dilute 1ml of SnO2 with ultrapure water to a 2.67wt% solution. Drop 45μL of the diluted SnO2 onto the ITO substrate and spin coat it using a spin coater at 3000 rpm for 30 seconds. Anneal the SnO2-coated ITO substrate at 150°C for 30 minutes. Place the annealed ITO substrate with the electron transport layer on a hot spin coater and preheat for 5 minutes.

[0055] 6. Take 80 μL of the reacted perovskite precursor solution and drop it onto the preheated ITO substrate. Spin-coat the solution and then anneal it to form a perovskite film. Spin-coat the perovskite precursor solution at 4000 rpm for 30 seconds. Anneal the solution at 150°C in dry air for 30 minutes.

[0056] 7. Weigh 73.2 mg of Spiro-MeOTAD and completely dissolve it in 1 ml of chlorobenzene. Stir and dissolve for 1 hour. Add 17.6 μL of lithium bis(trifluoromethanesulfonamide) dissolved in acetonitrile at a concentration of 520 mg / ml and stir and dissolve for 1 hour. Finally, add 28.8 μL of 4-tert-butylpyridine and stir and dissolve for 1 hour. Spin-coat the resulting hole transport material onto the perovskite film at 3000 rpm for 30 seconds to form a hole transport layer. Oxidize in air for 24 hours.

[0057] 8. Using vacuum evaporation technology, 5nm MoO3 was deposited on the hole transport layer, followed by 100nm of Au as the metal electrode to obtain a perovskite solar cell device. Under standard test conditions (AM1.5G illumination), the cell device prepared in this example had an energy conversion efficiency of 15.47%, an open circuit voltage of 0.958V, and a short circuit current of 25.98mA / cm 2 , the filling factor is 62.20%.

[0058] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

[0059] The above descriptions are only partial embodiments of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for synthesizing a perovskite precursor solution of a formamidine-based ionic liquid, characterized in that: include: Adding organic acid sodium salt and formamidine hydrochloride into ethanol respectively, stirring and dissolving, to obtain formamidine hydrochloride solution and alkyl acid sodium solution; Add the formamidine hydrochloride solution dropwise into the sodium alkylate solution, stir the mixture at 25-60°C, and react for 24-36 hours; The mixed solution after the reaction is filtered, and the filtrate is taken, and the first-level filtrate is subjected to rotary evaporation to remove the ethanol solvent, and then washed with an organic solvent for 25-35 minutes; The washed solution is filtered twice, the filtrate is taken, and the obtained secondary filtrate is subjected to rotary evaporation to remove the organic solvent to obtain an organic acid formamidine ionic liquid; Lead iodide and formamidine hydroiodide are dissolved in an organic acid formamidine ionic liquid, and reacted at 40-80° C. for at least 5 hours to obtain a perovskite precursor solution of the formamidine-based ionic liquid.

2. The synthesis method according to claim 1, characterized in that The molar ratio of the organic acid sodium salt to the formamidine hydrochloride is 1:1.5-2.

5.

3. The synthesis method according to claim 1, characterized in that Also includes: The obtained organic acid formamidine ionic liquid is dissolved in ethanol, and the ethanol is removed by rotary evaporation, which is repeated multiple times to obtain a pure alkyl acid formamidine ionic liquid.

4. The synthesis method according to claim 1, characterized in that Also includes: The molar ratio of the mixture of organic acid sodium salt and formamidine hydrochloride to ethanol is 1:5-8.

5. The synthesis method according to claim 1, characterized in that The organic acid sodium salt is at least one of sodium alkylate, sodium propionate or sodium butyrate.

6. A method for preparing a perovskite battery device, characterized in that: include: Cleaning the conductive glass substrate, spin coating the electron transport material on the conductive glass substrate, and spin coating the perovskite precursor solution of the formamidinium-based ionic liquid prepared by the synthesis method of any one of claims 1 to 5 on the electron transport layer of the conductive glass substrate, and annealing to form a formamidinium-based perovskite film; The hole transport layer material is spin-coated on the formamidinium-based perovskite film to obtain the hole transport layer, and a modification layer and a metal electrode are evaporated on the hole transport layer.

7. The preparation method according to claim 1, characterized in that: Also includes: Mixing SnO2 and deionized water in a mass ratio of 1:3-7 to obtain an electron transport layer material SnO2 solution; Spin-coat the SnO2 solution on the conductive substrate at 3500-4500 r / min for 20-40 seconds to form a film, and anneal at 120-180° C. for at least 30 minutes; The annealed conductive substrate spin-coated with the electron transport layer is subjected to ultraviolet ozone treatment for at least 10 minutes.

8. The preparation method according to claim 1, characterized in that: Also includes: Dissolve Spiro-OMeTAD in chlorobenzene, stir, add acetonitrile solution of lithium bis(trifluoromethanesulfonyl)imide and 4-tert-butylpyridine to form a hole transport layer material; At 3500-4500 r / min, the hole transport layer material is spin-coated on the surface of the AgBiS2 active layer for 20-40 seconds to form a film, and then oxidized in air for at least 24 hours.

9. The preparation method according to claim 1, characterized in that: The modification layer is MoO3 with a thickness of 3-7nm, and the metal electrode is Au or Ag with a thickness of 80-120nm.

10. A solar cell comprising the perovskite cell device according to any one of claims 6 to 9.

Images