A perovskite precursor solution, a perovskite composite film solution, and a preparation method and application thereof

Abstract

This invention belongs to the field of photoelectric conversion technology, and provides a perovskite precursor solution, a perovskite composite thin film solution, their preparation methods, and applications. The preparation method of this invention includes: mixing PbX2, octadecene, and oleylamine; adding a macromolecular polymer to the mixture to obtain a lead precursor solution; mixing cesium acetate, octadecene, and oleic acid; mixing the resulting cesium precursor solution with the lead precursor solution; and then cooling the mixture with ice water to obtain a perovskite precursor solution. The macromolecular polymer of this invention passivates Pb. 2+ The energy barrier defects left on the surface of the perovskite layer improve the stability of the perovskite, thereby improving the photoelectric conversion efficiency, fill factor and stability of the solar cell; titanium acetylacetone ligands improve the stability of the perovskite, and EVA is used to coat the perovskite crystals. The resulting perovskite composite film has good water resistance and flexibility, which improves the stability and optical performance of the perovskite composite film in humid environments.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photoelectric conversion, in particular to a perovskite precursor solution, a perovskite composite film solution and a preparation method and application thereof. BACKGROUND

[0002] Perovskite materials (lead cesium chloride) have high photoluminescence quantum yield (PLQY), tunable wavelength, wide absorption range and unique quantum confinement effect, and are favored by experts and scholars in the fields of solar cells, LED displays, photodetectors, gas sensing, etc. Perovskite nanocrystals have certain ionic crystal characteristics, which makes them easy to ionize and phase change in water or polar solvents, so they cannot exist in a humid environment for a long time. Ion migration will cause ion vacancies, increase the non-radiative recombination of excitons, and thus reduce the photoluminescence efficiency and photoelectric performance.

[0003] There are various synthesis methods for perovskite nanomaterials, such as ultrasonic method, microwave method, solvothermal method, hot injection method, etc., mainly hot injection method. However, the hot injection method has the following defects: on the one hand, the high-temperature hot injection method needs a high temperature in the reaction process, and it is difficult to control the reaction temperature in the fast injection and fast cooling reaction process, thus it is difficult to synthesize ideal products; on the other hand, in the synthesis of perovskite quantum dots, octadecenoic acid, octadecene, etc. are usually used as surface ligands to change the shape and size of the perovskite quantum dots, but these commonly used ligands have a long chain combined with the surface of the perovskite quantum dots, and the formed bond is extremely unstable, so the stability of the all-inorganic perovskite quantum dots cannot be guaranteed.

[0004] In practical applications, perovskite and surface ligands, etc. are of great significance to improve the performance of devices. The photoluminescence (PL) intensity of CsPbBr3 can be improved by passivating surface defects (such as cation or anion vacancy difference). For example, by doping polymers, organic ligands and inorganic ions (Yb 3+ , Sr 2+ , Mn 2+ , etc.) in perovskite NCs, the PLQY and stability can be greatly improved. In addition, the prior art discloses that the perovskite precursor is encapsulated in a polymethyl methacrylate fiber membrane to improve the stability of the perovskite composite film, and the perovskite precursor is embedded in polystyrene microspheres to prepare a stable fluorescent sensor. However, the above methods have the defects of relatively high price and time-consuming.

[0005] Therefore, it is of great significance to research a perovskite precursor solution and a perovskite composite film solution for improving the stability and photoelectric conversion efficiency of photoelectric devices. SUMMARY

[0006] The present application aims at providing a perovskite precursor solution, a perovskite composite thin film solution, a preparation method and application thereof to overcome the deficiencies of the prior art.

[0007] To achieve the above-mentioned application purposes, the present application provides the following technical solutions.

[0008] The present application provides a preparation method of a perovskite precursor solution, comprising the following steps:

[0009] 1) mixing PbX2, octadecene and oleylamine to obtain a mixed solution; adding a macromolecular polymer into the mixed solution to obtain a lead precursor solution;

[0010] 2) mixing cesium acetate, octadecene and oleic acid to obtain a cesium precursor solution;

[0011] 3) mixing the cesium precursor solution and the lead precursor solution and then cooling with ice water to obtain a perovskite precursor solution;

[0012] The perovskite precursor is CsPbX3, and X in PbX2 and CsPbX3 is I, Br or Cl.

[0013] As a preference, the macromolecular polymer is obtained by polymerization of 4,4'-(hexafluoroisopropylene) diphthalic anhydride and 2,2-bis(3-amino-4-hydroxyphenyl) hexafluoropropane.

[0014] As a preference, in the mixed solution of step 1), the molar concentration of PbX2 is 0.05-0.15 mol / L, the volume ratio of the octadecene and oleylamine is 10-15:1-3, and the mass ratio of the macromolecular polymer and PbX2 is 0.02-0.1:100.

[0015] As a preference, in the cesium precursor solution of step 2), the molar concentration of cesium acetate is 0.05-0.15 mol / L, the volume ratio of the octadecene and oleic acid is 8-10:1, and the molar ratio of cesium acetate and PbX2 of step 1) is 3:4-6.

[0016] As a preference, the mixing of steps 1) and 2) is carried out under a nitrogen atmosphere, and the mixing time of step 3) is 10-20 s, and the mixing temperature is 130-150℃.

[0017] The present application also provides a perovskite precursor solution prepared by the preparation method.

[0018] The present application also provides a method for preparing a perovskite composite thin film solution from the perovskite precursor solution, comprising the following steps:

[0019] The perovskite precursor solution and the titanium acetylacetonate solution are mixed and then added into a toluene solution of ethylene-vinyl acetate copolymer to obtain a perovskite composite film solution.

[0020] The application further provides a perovskite composite film solution prepared by a method for preparing a perovskite composite film solution from the perovskite precursor solution.

[0021] The application further provides application of the perovskite precursor solution or the perovskite composite film solution in photoelectric devices.

[0022] The application has the following advantages:

[0023] 1) The macromolecular polymer is obtained by polymerization of 4,4'-(hexafluoroisopropylidene)diphthalic anhydride and 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, and the macromolecular polymer contains a large number of carbonyl groups and trifluoromethyl groups, which can provide sufficient lone pair electrons to coordinate with the unfilled p orbitals of Pb 2+ , passivate Pb 2+ , leave energy barrier defects on the surface of the perovskite layer, reduce non-radiative recombination at the perovskite interface and grain boundary, promote the vertical transmission of charges, increase the purity of the perovskite CsPbX3 to more than 99.99%, and improve the stability of the perovskite, thereby improving the photoelectric conversion efficiency, fill factor and stability of the solar cell.

[0024] 2) The titanium acetylacetonate ligand is used to improve the stability of the perovskite, and when exposed to air, the surface Ti-based ligand is oxidized to TiO2 to encapsulate the perovskite crystals; the ethylene-vinyl acetate copolymer (EVA) is used to coat the perovskite crystals, and the obtained perovskite composite film has good regularity, excellent waterproofness and flexibility, improves the stability and optical performance of the perovskite composite film in a humid environment, and further improves the photoelectric conversion efficiency of the photoelectric device such as a solar cell.

[0025] 3) The perovskite composite film binds the lead ions in the perovskite through the interaction between EVA and the perovskite, and prevents the lead ions from interacting with environmental water molecules, thereby improving the carrier mobility and the photoelectric performance of the perovskite composite film and prolonging the service life of the material; the coating of EVA and the bonding of the macromolecular polymer to the lead ions enable the perovskite composite film to have long-term stability in air and water and at high temperatures, and the photoelectric performance is significantly improved. DETAILED DESCRIPTION

[0026] The application provides a preparation method of a perovskite precursor solution, which comprises the following steps:

[0027] 1) mixing PbX2, octadecene and oleylamine to obtain a mixed solution; adding a macromolecular polymer into the mixed solution to obtain a lead precursor solution;

[0028] 2) mixing cesium acetate, octadecene and oleic acid to obtain a cesium precursor solution;

[0029] 3) mixing the cesium precursor solution and the lead precursor solution and then cooling with ice water to obtain a perovskite precursor solution;

[0030] The perovskite precursor is CsPbX3, and X in PbX2 and CsPbX3 is I, Br or Cl.

[0031] In the application, the macromolecular polymer is preferably obtained by polymerization of 4,4'-(hexafluoroisopropylidene) diphthalic anhydride and 2,2-bis(3-amino-4-hydroxyphenyl) hexafluoropropane.

[0032] In the application, the macromolecular polymer is prepared by mixing 4,4'-(hexafluoroisopropylidene) diphthalic anhydride, 2,2-bis(3-amino-4-hydroxyphenyl) hexafluoropropane and a solvent and then polymerizing to obtain the macromolecular polymer, and the molar volume ratio of 4,4'-(hexafluoroisopropylidene) diphthalic anhydride, 2,2-bis(3-amino-4-hydroxyphenyl) hexafluoropropane and the solvent is preferably 1-1.5 mol: 1-1.5 mol: 30-50 mL, further preferably 1-1.2 mol: 1-1.2 mol: 35-45 mL, and more preferably 1.2 mol: 1.2 mol: 36-40 mL; the polymerization time is preferably 8-10 h, further preferably 8.5-9.5 h, and more preferably 9 h; the polymerization temperature is preferably 30-50℃, further preferably 35-45℃, and more preferably 40℃; and the polymerization is carried out under stirring.

[0033] In the application, in the mixed solution of step 1), the molar concentration of PbX2 is preferably 0.05-0.15 mol / L, further preferably 0.08-0.12 mol / L, and more preferably 0.1 mol / L; the volume ratio of octadecene and oleylamine is preferably 10-15: 1-3, further preferably 11-14: 1.5-2.5, and more preferably 12-13: 2; and the mass ratio of the macromolecular polymer and PbX2 is preferably 0.02-0.1: 100, further preferably 0.04-0.08: 100, and more preferably 0.05-0.06: 100.

[0034] In the present application, the molar concentration of cesium acetate in the cesium precursor solution of step 2) is preferably 0.05-0.15 mol / L, further preferably 0.08-0.12 mol / L, and more preferably 0.1 mol / L; the volume ratio of octadecene to oleic acid is preferably 8-10:1, and further preferably 9:1; the molar ratio of cesium acetate to PbX2 in step 1) is preferably 3:4-6, further preferably 3:4.5-5.5, and more preferably 3:5.

[0035] In the present application, the mixing in steps 1) and 2) is preferably carried out under a nitrogen atmosphere, and the mixing time in step 3) is preferably 10-20 s, further preferably 12-18 s, and more preferably 14-15 s; the mixing temperature is preferably 130-150℃, further preferably 135-145℃, and more preferably 140℃.

[0036] The present application also provides a perovskite precursor solution prepared by the preparation method.

[0037] The present application also provides a method for preparing a perovskite composite thin film solution from the perovskite precursor solution.

[0038] After mixing the perovskite precursor solution and the titanium acetylacetonate solution, they are added to a toluene solution of ethylene-vinyl acetate copolymer to obtain a perovskite composite thin film solution.

[0039] In the present application, the ethylene-vinyl acetate copolymer is dispersed in toluene by ultrasonic dispersion, and the mixed solution of the perovskite precursor solution and the titanium acetylacetonate solution is added under stirring to obtain a perovskite composite thin film solution; the volume ratio of the perovskite precursor solution to the titanium acetylacetonate solution is preferably 1:3-5, further preferably 1:3.5-4.5, and more preferably 1:4; the concentration of the titanium acetylacetonate solution is preferably 4-7 mg / L, and further preferably 5-6 mg / L; the volume ratio of the perovskite precursor solution to toluene is preferably 2-60 μL:1 mL, further preferably 10-40 μL:1 mL, and more preferably 20-30 μL:1 mL; and the mass-volume ratio of the ethylene-vinyl acetate copolymer to toluene is preferably 0.05-0.15 g:1 mL, further preferably 0.06-0.12 g:1 mL, and more preferably 0.08-0.1 g:1 mL.

[0040] The present application also provides a perovskite composite thin film solution prepared by the method for preparing a perovskite composite thin film solution from the perovskite precursor solution.

[0041] The present application also provides the use of the perovskite precursor solution or the perovskite composite thin film solution in photoelectric devices.

[0042] The technical solutions provided by the present application will be described in detail below in conjunction with the embodiments, but they should not be construed as limiting the scope of protection of the present application.

[0043] In the embodiment, the macromolecular polymer is prepared by adding 1 mol of 4,4'-(hexafluoroisopropylidene) diphthalic anhydride and 1 mol of 2,2-bis(3-amino-4-hydroxyphenyl) hexafluoropropane in 30 mL of N,N-dimethylformamide, and performing polymerization at 40°C and a rotation speed of 500 r / min for 9 h, and then adding deionized water to precipitate the solid, and performing suction filtration and drying to obtain the macromolecular polymer.

[0044] Example 1

[0045] The lead bromide, octadecene and oleylamine are mixed under a nitrogen atmosphere to obtain a mixed solution, in which the concentration of the lead bromide is 0.1 mol / L, and the volume ratio of the octadecene to the oleylamine is 12:2; the macromolecular polymer is added to the mixed solution to obtain a lead precursor solution, and the mass ratio of the macromolecular polymer to the lead bromide is 0.05:100. The cesium acetate, octadecene and oleic acid are mixed under a nitrogen atmosphere to obtain a cesium precursor solution, in which the concentration of the cesium acetate is 0.1 mol / L, and the volume ratio of the octadecene to the oleic acid is 9:1.

[0046] The cesium precursor solution is rapidly added to the lead precursor solution (the molar ratio of the cesium acetate to the lead bromide is 3:5) at 140°C, and mixed for 12 s, and then cooled with ice water to obtain a perovskite precursor (CsPbBr3) solution.

[0047] The perovskite precursor solution and the aqueous titanium acetylacetonate solution (in the aqueous titanium acetylacetonate solution, the concentration of the titanium acetylacetonate is 5 mg / L) are mixed in a volume ratio of 1:4, and then the mixed solution is added to a toluene solution of the ethylene-vinyl acetate copolymer to obtain a perovskite composite film solution, in which the volume ratio of the perovskite precursor solution to the toluene is 20 μL:1 mL, and the mass-volume ratio of the ethylene-vinyl acetate copolymer to the toluene is 0.1 g:1 mL.

[0048] The purity of CsPbBr3 in the perovskite precursor solution of the embodiment is 99.995%.

[0049] Example 2

[0050] The lead iodide, octadecene and oleylamine were mixed under a nitrogen atmosphere to obtain a mixed solution, in which the concentration of the lead iodide was 0.08 mol / L, and the volume ratio of the octadecene to the oleylamine was 11:1.5; the macromolecular polymer was added to the mixed solution to obtain a lead precursor solution, and the mass ratio of the macromolecular polymer to the lead iodide was 0.06:100. The cesium acetate, octadecene and oleic acid were mixed under a nitrogen atmosphere to obtain a cesium precursor solution, in which the concentration of the cesium acetate was 0.08 mol / L, and the volume ratio of the octadecene to the oleic acid was 8:1.

[0051] The cesium precursor solution was rapidly added to the lead precursor solution (the molar ratio of the cesium acetate to the lead iodide was 3:4.5) at 135°C, and the perovskite precursor (CsPbI3) solution was obtained after mixing for 10 s and cooling with ice water.

[0052] The perovskite precursor solution and the aqueous titanium acetylacetonate solution (in which the concentration of the titanium acetylacetonate was 4 mg / L) were mixed in a volume ratio of 1:3, and the mixture was added to the toluene solution of the ethylene-vinyl acetate copolymer to obtain a perovskite composite film solution, in which the volume ratio of the perovskite precursor solution to the toluene was 10 μL:1 mL, and the mass-volume ratio of the ethylene-vinyl acetate copolymer to the toluene was 0.06 g:1 mL.

[0053] The purity of CsPbI3 in the perovskite precursor solution of this example was 99.991%.

[0054] Example 3

[0055] The lead bromide, octadecene and oleylamine were mixed under a nitrogen atmosphere to obtain a mixed solution, in which the concentration of the lead bromide was 0.12 mol / L, and the volume ratio of the octadecene to the oleylamine was 14:2.5; the macromolecular polymer was added to the mixed solution to obtain a lead precursor solution, and the mass ratio of the macromolecular polymer to the lead bromide was 0.07:100. The cesium acetate, octadecene and oleic acid were mixed under a nitrogen atmosphere to obtain a cesium precursor solution, in which the concentration of the cesium acetate was 0.12 mol / L, and the volume ratio of the octadecene to the oleic acid was 10:1.

[0056] The cesium precursor solution was rapidly added to the lead precursor solution (the molar ratio of the cesium acetate to the lead bromide was 3:5.5) at 145°C, and the perovskite precursor (CsPbBr3) solution was obtained after mixing for 15 s and cooling with ice water.

[0057] The perovskite precursor solution and the aqueous titanium acetylacetonate solution (6 mg / L of titanium acetylacetonate in the aqueous titanium acetylacetonate solution) in a volume ratio of 1:5 were mixed, and the mixture was added to the toluene solution of the ethylene-vinyl acetate copolymer to obtain a perovskite composite thin film solution, the volume ratio of the perovskite precursor solution to toluene being 40 μL:1 mL, and the mass-volume ratio of the ethylene-vinyl acetate copolymer to toluene being 0.12 g:1 mL.

[0058] The purity of CsPbBr3 in the perovskite precursor solution of this example was 99.993%.

[0059] Comparative Example 1

[0060] The macromolecular polymer of Example 1 was omitted, and the other conditions were the same as in Example 1.

[0061] Comparative Example 2

[0062] The aqueous titanium acetylacetonate solution of Example 1 was omitted, and the mass ratio of the macromolecular polymer to lead bromide was changed to 0.01:100, and the other conditions were the same as in Example 1.

[0063] Polymer perovskite solar cells were prepared using the perovskite composite thin film solutions of Examples 1-3, and the specific preparation process was as follows: ITO conductive glass was used as a substrate, and the substrate was ultrasonically cleaned with acetone, isopropanol, deionized water, and alcohol for 15 min, and then dried with nitrogen, and ultraviolet ozone cleaned for 15 min, and then quickly transferred to a nitrogen atmosphere glove box. 20 μL of 3 mg / mL poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] was spin-coated on the surface of the conductive glass, and then transferred to a heating stage at 100°C for 10 min to obtain a hole transport layer. The perovskite composite thin film solution (60 μL) of the example and the comparative example was spin-coated on the surface of the hole transport layer, and then 30 μL of toluene was added, and then transferred to a heating stage at 100°C for 10 min to obtain a perovskite composite thin film layer. 35 μL of an electron transport layer solution (23 mg of [6,6]-phenyl C61 butyric acid methyl ester dissolved in 1 mL of chlorobenzene) was spin-coated on the surface of the perovskite composite thin film layer, and then transferred to a heating stage at 100°C for 10 min, and then 45 μL of 2.5 mg / mL bathocuproine was spin-coated to obtain an electron transport layer. Finally, the substrate on which the electron transport layer was prepared was placed in a vacuum coating machine, and vacuumized to a vacuum degree of 100 Pa, and a silver metal source was placed in a tungsten boat, and silver metal electrodes were evaporated to obtain a polymer perovskite solar cell. The performance of the polymer perovskite solar cell was tested.

[0064] The photoelectric conversion efficiencies of the solar cells of Examples 1-3 were 27.5%, 27.3%, and 26.9%, respectively, and the fill factors were 82.56%, 82.48%, and 82.52%, respectively. The photoelectric conversion efficiencies of the solar cells of Comparative Examples 1 and 2 were 20.56% and 21.18%, respectively, and the fill factors were 77.52% and 78.16%, respectively.

[0065] 30 μL of toluene was added dropwise to 60 μL of the perovskite composite film solution of Examples 1-3 and Comparative Examples 1-2, respectively, and then transferred to a heating stage at 100°C for heating for 10 min to obtain perovskite composite films, which were subjected to stability tests. The specific process for the stability tests was as follows: the perovskite films were soaked in water and then dried, and the phase thereof was determined using an X-ray diffractometer to observe whether the phase had changed. The results showed that the perovskite composite films of Examples 1-3 did not change significantly in phase after being soaked in water for 40 days, and had very high water stability; the perovskite films of Comparative Examples 1-2 changed significantly after being soaked in water for 20 days.

[0066] The perovskite composite film solutions of Examples 1-3 and Comparative Examples 1-2 were heated to 70°C, and the changes in the morphology thereof were observed. The results showed that the perovskite composite films of Examples 1-3 still maintained the original morphology after 200 min, and had excellent high-temperature morphology stability; the perovskite films of Comparative Examples 1-2 changed significantly in morphology after 130 min and 145 min, respectively.

[0067] The above only describes the preferred embodiments of the present application, and it should be noted that, for those skilled in the art, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as falling within the scope of the present application.

Claims

1. A method for preparing perovskite composite thin film solution from perovskite precursor solution, characterized in that, It includes the following steps: The perovskite precursor solution and the titanium acetylacetone solution were mixed and then added to a toluene solution of ethylene-vinyl acetate copolymer to obtain a perovskite composite film solution. The method for preparing the perovskite precursor solution includes the following steps: 1) PbX2, octadecene and oleylamine were mixed to obtain a mixture; a macromolecular polymer was added to the mixture to obtain a lead precursor solution; 2) Cesium acetate, octadecene, and oleic acid are mixed to obtain a cesium precursor solution; 3) The cesium precursor solution and the lead precursor solution were mixed and cooled with ice water to obtain the perovskite precursor solution; The perovskite precursor is CsPbX3, and X in PbX2 and CsPbX3 is I, Br or Cl.

2. The method for preparing perovskite composite thin film solution from perovskite precursor solution according to claim 1, characterized in that, The macromolecular polymer is obtained by polymerization of 4,4'-(hexafluoroisopropene)phthalic anhydride and 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane.

3. The method for preparing perovskite composite thin film solution from perovskite precursor solution according to claim 1, characterized in that, In step 1), the molar concentration of PbX2 in the mixture is 0.05~0.15 mol / L, the volume ratio of octadecene to oleylamine is 10~15:1~3, and the mass ratio of macromolecular polymer to PbX2 is 0.02~0.1:

100.

4. The method for preparing perovskite composite thin film solution from perovskite precursor solution according to claim 1 or 3, characterized in that, In step 2), the molar concentration of cesium acetate in the cesium precursor solution is 0.05~0.15 mol / L, the volume ratio of octadecene to oleic acid is 8~10:1, and the molar ratio of cesium acetate to PbX2 in step 1) is 3:4~6.

5. The method for preparing perovskite composite thin film solution from perovskite precursor solution according to claim 4, characterized in that, The mixing in steps 1) and 2) is carried out under a nitrogen atmosphere, and the mixing time in step 3) is 10~20s, and the mixing temperature is 130~150℃.

6. The perovskite composite thin film solution prepared by the method for preparing perovskite composite thin film solution according to any one of claims 1 to 5.

7. The application of the perovskite composite thin film solution according to claim 6 in optoelectronic devices.