Perovskite precursor solution and application thereof in preparation of perovskite layer in perovskite battery

Abstract

The invention discloses a perovskite precursor solution. The perovskite precursor solution contains a double-dipole ionic compound, the perovskite precursor solution is used for preparing a perovskite layer in a perovskite battery. The solution utilizes additive engineering to improve perovskite cell efficiency and stability. The double dipole ionic compound is added into the perovskite precursor solution based on the green solvent to serve as an additive to effectively passivate defects, reduce non-radiative recombination and prolong the service life of carriers, so that the efficiency and stability of the perovskite battery are remarkably improved.

Description

Technical Field

[0001] This application relates to a perovskite precursor solution and its application in the preparation of a perovskite layer in a perovskite solar cell, belonging to the field of solar cell technology. Background Technology

[0002] Perovskite solar cells, as a novel photovoltaic technology, have attracted considerable attention due to their excellent photoelectric properties, such as low production cost, long carrier diffusion distance, and tunable bandgap. In just over a decade, their energy conversion efficiency has rapidly increased, with certified efficiencies exceeding 27% for small-area single-junction perovskite cells. Despite significant progress in recent years, most current perovskite precursor solutions utilize polar aprotic solvents to dissolve lead iodide and alkyl halides, such as N,N-dimethylformamide (DMF) and N-methyl-2-pyrrolidone (NMP). These organic solvents pose a potentially significant threat to human health and present major challenges to the industrial production and commercial application of perovskite solar cells. Therefore, there is an urgent need to develop green solvent systems and improve the efficiency and stability of perovskite solar cells based on these systems. Summary of the Invention

[0003] According to one aspect of this application, a method is provided for improving the efficiency and stability of perovskite solar cells using additive engineering, based on a perovskite precursor solution. This method effectively passivates defects, reduces non-radiative recombination, and increases carrier lifetime by adding a bipolar ion compound as an additive to a green solvent-based perovskite precursor solution, thereby significantly improving the efficiency and stability of the perovskite solar cell.

[0004] The perovskite precursor solution contains a double-dipole ion compound; the perovskite precursor solution is used to prepare the perovskite layer in a perovskite solar cell. The solution contains a solvent; the solvent includes alcohols, N,N-dimethylacetamide, acetonitrile, and 2-methoxyethanol.

[0005] Preferably, the concentration of the bipolar ion compound is 0.1 ~ 5 mg / mL.

[0006] The bipolar ion compound is selected from compounds containing both carboxyl and amino groups; the hydrogen atom on the carboxyl group can be transferred to the nitrogen atom to form a bipolar ion.

[0007] In the bipolar ion compound, the carboxyl group is represented by -COO. - It exists in the form of N; the N in the amino group is N + It exists in the form of.

[0008] Preferably, the bipolar ion compound is selected from at least one of ethylenediaminetetraacetic acid, ethylenediaminetetraacetic acid salt, citric acid, tartaric acid, gluconic acid, aminotriacetic acid, diethylenetriaminepentaacetic acid, hydroxyethylethylenediaminetriacetic acid, and dihydroxyethylglycine.

[0009] More preferably, the bipolar ion compound is selected from ethylenediaminetetraacetic acid.

[0010] The solution contains a solvent. The solvent is a green solvent.

[0011] The green solvent primarily uses alcohols as solvents, while also incorporating N,N-dimethylacetamide (DMA), acetonitrile (ACN), and 2-methoxyethanol (2ME) to form a mixed green solvent system. The alcohols include one or more of methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, and n-pentanol, with the alcohols comprising 30% to 70% of the mixed green solvent.

[0012] Preferably, the solvent includes alcohols, N,N-dimethylacetamide, acetonitrile, and 2-methoxyethanol; The alcohol compound has a volume percentage of 30wt% to 70wt% in the solvent.

[0013] Preferably, the volume ratio of N,N-dimethylacetamide, acetonitrile, and 2-methoxyethanol is 1:0.01~1:0.01~1; More preferably, the volume ratio of N,N-dimethylacetamide, acetonitrile, and 2-methoxyethanol is 1:0.08:0.25.

[0014] The solution contains a solute perovskite precursor.

[0015] Preferably, the perovskite precursor comprises lead salt, amine salt, and co-solvent.

[0016] Preferably, the lead salt is lead halide PbX2, where X is any one of the halogen elements.

[0017] Preferably, the ammonium salt is selected from at least one of iodoformamidine, iodoformamine, bromoformamidine, and bromoformamine.

[0018] Preferably, the co-solvent is alkylammonium chloride RNH3Cl, where R is selected from any one of C1 to C5 alkyl groups.

[0019] Preferably, the molar ratio of the lead salt to the ammonium salt is 1:1.

[0020] Preferably, the molar ratio of the lead salt to the co-solvent is 100:10~40.

[0021] Preferably, the concentration of the lead salt in the solution is 1.0 mol / L to 2.0 mol / L.

[0022] According to another aspect of this application, the use of the solution in the preparation of a perovskite layer in a perovskite solar cell is provided.

[0023] Preferably, the thickness of the perovskite layer is 100~1000 nm.

[0024] The perovskite solar cell includes a substrate, a transparent conductive electrode, a hole transport layer, a perovskite layer, an electron transport layer, a metal electrode layer, and a modified passivation layer. The perovskite layer is obtained by coating the hole transport layer with the solution and then annealing it. The annealing temperature is 80℃~150℃, the annealing time is 10~30min, and the annealing atmosphere is air or a non-reactive atmosphere; The inactive atmosphere is selected from at least one of nitrogen and inert gases.

[0025] Specifically, the substrate is selected from one of glass, metal plate, polyethylene terephthalate plastic, polyethylene naphthalate plastic, polyimide plastic and metal foil; The transparent conductive electrode comprises indium tin oxide or FTO; The hole transport layer comprises a self-assembled monolayer material, NiO. x At least one of CuI, Cu2O, 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene, 2,2',7,7'-tetratetra[N,N-di(4-tolyl)amino]-9,9'-spirodifluorene, N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine, and poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine]; The electron transport layer includes at least one of ZnO, TiO2, SnO2, methyl [6,6]-phenyl-C61-butyrate, and C60; The metal electrode layer includes at least one of Au, Ag, Cu, Al, Ni, Ti, and Cr; The modified passivation layer includes at least one of phenylethyl iodide, 1,3-propanediamine hydroiodate, magnesium fluoride, lithium fluoride, piperazine hydroiodate, and phenylethyl iodide bromide.

[0026] In this application: “DMA” is short for N,N-dimethylacetamide; “ACN” is short for acetonitrile; “2ME” is short for 2-methoxyethanol; "EDTA" is short for ethylenediaminetetraacetic acid; “PET” is short for polyethylene terephthalate; “PEN” is short for polyethylene naphthalate; “PI” is short for polyimide; "ITO" is short for indium tin oxide; "FTO" is short for fluorine-doped tin oxide; “SAM” is short for self-assembled monolayer, and all self-assembled monolayer materials are eligible. “Spiro-OMeTAD” is an abbreviation for 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene; “Spiro-TTB” is an abbreviation for 2,2',7,7'-tetrakis[N,N-di(4-tolyl)amino]-9,9'-spirodifluorene; “NPB” is short for N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine; “PTAA” is short for poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine]; "PEAI" is the abbreviation for phenylethyl iodide. “PDADI” is an abbreviation for 1,3-propanediamine hydroiodide. “PipDI” is the abbreviation for piperazine hydroiodide. "PEABr" is the abbreviation for phenylethylamine bromide.

[0027] The beneficial effects of this application include, but are not limited to: (1) The perovskite precursor solution provided in this application adopts a green solvent system, which greatly reduces the harm caused by polar aprotic solvents in traditional solution systems, and is conducive to the industrial production and commercial application of perovskite batteries.

[0028] (2) The perovskite precursor solution provided in this application contains a double dipole ion compound that can effectively passivate defects, reduce non-radiative recombination, and increase carrier lifetime, thereby significantly improving the efficiency and stability of perovskite solar cells. Attached Figure Description

[0029] Figure 1 This is a comparison of the Zeta potential diagrams of solution DS1# (Control) and solution S1# (Target).

[0030] Figure 2 This is a comparison of the particle size distribution of colloidal particles in solution DS1# (Control) and solution S1# (Target).

[0031] Figure 3 These are scanning electron microscope (SEM) images of perovskite layers L1# and DL1#. Among them: (a) is a surface SEM of DL1#; (b) is a surface SEM of L1#; (c) is a cross-sectional SEM of DL1#; and (d) is a cross-sectional SEM of L1#.

[0032] Figure 4 These are the results of space charge confinement current (SCLC) tests. Among them: (a) SCLC with only holes; (b) SCLC with only electrons.

[0033] Figure 5 This is a comparison of the stability of perovskite solar cells C1# and DC1# in a dryer. Detailed Implementation

[0034] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0035] Unless otherwise specified, all raw materials and reagents used in this application are commercially purchased and used directly without processing. The instruments and equipment used adopt the manufacturer's recommended scheme and parameters.

[0036] In the embodiment, the particle size distribution and Zeta potential were both tested using a Malvern nanolaser particle size analyzer, with an equilibration time of 60 s, a test angle of 90°, continuous operation for 11 hours, and a running time of 10 s.

[0037] The scanning electron microscope (SEM) images were acquired using a SU8020 field emission scanning electron microscope with an accelerating voltage of 2.5 kV.

[0038] Space current-limited charge (SCLC) testing was conducted in the dark using a Keithley 2450 digital source meter and a Keysight B2901A simulator, with a scan range of 0 V to 3 V. Dryer stability testing was conducted under AM1.5 G single-day sunlight using a Keithley 2450 digital source meter and an Enlitech SS-F5 simulator, with a scan range of 1.2 V to -0.1 V.

[0039] Example 1: Preparation of solutions S1# to S5# After dissolving the perovskite precursor in a mixed solvent, a double dipolar ion compound is added. The specific types, concentrations, and ratios of the perovskite precursor, mixed solvent, and double dipolar ion compound are detailed in Table 1.

[0040] Table 1

[0041] Preparation of solution DS1# in Comparative Example 1 The preparation steps and raw material ratios are the same as those for solution S1#, except that EDTA is not added, and the resulting solution is denoted as solution DS1#.

[0042] Example 2 Characterization of solutions S1#~S5# and DS1# The Zeta potentials of solutions S1#~S5# and DS1# were tested respectively, and the results showed that the Zeta potentials of solutions S1#~S5# were all greater than 2mV.

[0043] Taking S1# as a typical example, a comparison of its Zeta potential with DS1# can be found in [link to documentation]. Figure 1 .

[0044] Depend on Figure 1 It can be seen that the Zeta potential increased from 0.547 (control) to 2.87 (target), proving that the introduction of EDTA improved the stability of the perovskite colloid.

[0045] The particle size distribution of colloidal particles in solutions S1#~S5# and DS1# was tested respectively. The results showed that the polydispersity index (PDI) of the particle size distribution in solutions S1#~S5# was less than 0.07.

[0046] Taking S1# as a typical example, a detailed comparison of its particle size distribution with DS1# can be found in [link to relevant documentation]. Figure 2 .

[0047] Depend on Figure 2 It can be seen that the introduction of EDTA leads to a more concentrated particle size distribution around the average particle size, and the polydispersity index (PDI) decreases from 0.086 (control) to 0.062 (target). Example 3: Preparation and characterization of perovskite layers L1#~L5# and DL1# The FTO glass was ultrasonically cleaned with acetone, isopropanol and ethanol for 30 min each, and then dried with a nitrogen gun to serve as a substrate with a transparent conductive electrode.

[0048] Solutions S1#~S5# and DS1# were spin-coated onto FTO glass, respectively, and then annealed to form a perovskite layer. The specific operation steps and conditions were as follows: spin-coating speed 4000 rpm, time 30 s, followed by annealing at 150℃ for 20 minutes. The resulting perovskite layers were denoted as perovskite layers L1#~L5# and DL1#, respectively.

[0049] Scanning electron microscopy characterization of perovskite layers L1#~L5# and DL1# showed that L1#~L5# were uniformly distributed and had a uniform thickness.

[0050] Taking L1# as a typical example, a detailed comparison of its scanning electron microscope images with DL1# can be found in [link to relevant documentation]. Figure 3 .

[0051] Depend on Figure 3 It can be seen that, compared with DL1 perovskite film, L1 perovskite film has significantly fewer pores, and its film quality is significantly better than that of DL1 perovskite film.

[0052] Example 4: Fabrication of perovskite solar cells C1#~C5# and DC1# The substrate with the transparent conductive electrode was ultrasonically cleaned with acetone, isopropanol and ethanol for 30 min respectively, and then dried with a nitrogen gun for later use.

[0053] A hole transport layer was prepared on a substrate with a transparent conductive electrode. The specific operation steps and conditions were as follows: 23 nm of NiOx was evaporated by electron beam at an evaporation rate of 0.5 A / s.

[0054] Solutions S1#~S5# and DS1# were spin-coated onto the hole transport layer, and then annealed to form a perovskite layer. The specific operation steps and conditions were as follows: spin coating speed 4000 rpm, time 30 s, and then annealing at 150℃ for 20 minutes.

[0055] The modification and passivation material is coated onto the perovskite layer and then annealed to form the modification and passivation layer. The specific operation steps and conditions are as follows: spin coating PDADI at 3000 rpm for 30 s, followed by annealing at 100℃ for 10 min.

[0056] The electron transport layer material was spin-coated onto the modified passivation layer. The specific operation steps and conditions were as follows: spin-coating PCBM at 4000 rpm for 30 s; then spin-coating BCP at 5000 rpm for 30 s.

[0057] Metal electrode layers are prepared by thermal evaporation.

[0058] Table 2

[0059] Example 5: Stability characterization of perovskite solar cells C1#~C5# and DC1# The stability of perovskite solar cells C1#~C5# and DC1# was characterized using the following methods: (1) Store unencapsulated perovskite cells in a desiccator.

[0060] (2) In an N2 environment, the unencapsulated perovskite cells were stored on a hot plate at 85°C.

[0061] (3) After encapsulating the perovskite battery, store it in an atmospheric environment.

[0062] (4) After encapsulating the perovskite solar cells, store them in a thermal cycling chamber. The temperature range in the thermal cycling chamber is -15℃ to 85℃, and the relative humidity is <1%.

[0063] The JV curve of the perovskite solar cell was tested at AM 1.5G.

[0064] The results show that all perovskite solar cells C1#~C5# can maintain 80% of their initial efficiency for more than 1000 hours.

[0065] Taking C1# as a typical example, a comparison of its stability with DC1# can be found in [link to documentation]. Figure 5 . Depend on Figure 5 It can be seen that the perovskite device with added EDTA can still maintain 80% of its initial efficiency after being placed in a dryer for 1200 hours, while the device without added EDTA can only maintain it for about 600 hours.

[0066] Example 6: Measurement of space charge-limited current The specific operating methods and steps are as follows: For SCLCs with pure hole transport, NiOx, perovskite, and Spiro-OMeTAD are sequentially spin-coated onto an FTO glass substrate, followed by thermal evaporation of a 150 nm Au electrode. For SCLCs with pure electron transport, SnO2, perovskite, PCBM, and BCP are sequentially spin-coated onto an FTO glass substrate, followed by thermal evaporation of a 150 nm Ag electrode.

[0067] The results are as follows Figure 4 As shown, Figure 4 (a) shows the dark current density-voltage (JV) curves for the hole transport device, where the trap fill limit voltage (VV) without EDTA is shown. TFL The voltage is 0.141 V when EDTA is added, and 0.098 V when EDTA is added. Figure 4 (b) shows the dark JV curve for only the electronic transmission device, where the V of the control device... TFL The value is 0.281 V, the target V TFL The value is 0.155 V. TFL The decrease in the value proves that the addition of EDTA can reduce the trapped states of perovskite films and improve the film quality.

[0068] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A perovskite precursor solution, characterized in that, Contains a compound with a double dipole ion; The perovskite precursor solution is used to prepare the perovskite layer in perovskite solar cells. The solution contains a solvent; the solvent includes alcohols, N,N-dimethylacetamide, acetonitrile, and 2-methoxyethanol.

2. The solution according to claim 1, characterized in that, The concentration of the bipolar ion compound is 0.1~5 mg / mL.

3. The solution according to claim 1, characterized in that, The bipolar ion compound is selected from compounds that simultaneously contain carboxyl and amino groups; In the bipolar ion compound, the carboxyl group is represented by -COO. - The N in the amino group exists in the form of N. + It exists in the form of.

4. The solution according to claim 1, characterized in that, The bipolar ion compound is selected from at least one of ethylenediaminetetraacetic acid, ethylenediaminetetraacetic acid salt, citric acid, tartaric acid, gluconic acid, aminotriacetic acid, diethylenetriaminepentaacetic acid, hydroxyethylethylenediaminetriacetic acid, and dihydroxyethylglycine.

5. The solution according to claim 1, characterized in that, The alcohol compound has a volume content of 30% to 70% in the solvent; The volume ratio of N,N-dimethylacetamide, acetonitrile, and 2-methoxyethanol is 1:0.01~1:0.01~1; Preferably, the molar ratio of N,N-dimethylacetamide, acetonitrile and 2-methoxyethanol is 1:0.08:0.

25.

6. The solution according to claim 1, characterized in that, The solution contains a solute perovskite precursor; The perovskite precursor includes lead salt, amine salt and co-solvent; The lead salt is lead halide PbX2, where X is any one of the halogen elements; The ammonium salt is selected from at least one of iodoformamidine, iodoformamide, and bromoformamidine; The co-solvent is alkylammonium chloride RNH3Cl, where R is selected from any one of C1 to C5 alkyl groups; The molar ratio of the lead salt to the ammonium salt is 1:1; The molar ratio of the lead salt to the co-solvent is 100:10~40; The concentration of the lead salt in the solution is 1.0 mol / L to 2.0 mol / L.

7. The use of the solution according to claims 1 to 6 in the preparation of the perovskite layer in a perovskite solar cell.

8. The application according to claim 7, characterized in that, The thickness of the perovskite layer is 100~1000nm.

9. The application according to claim 7, characterized in that, The perovskite solar cell includes a substrate, a transparent conductive electrode, a hole transport layer, a perovskite layer, an electron transport layer, a metal electrode layer, and a modified passivation layer. The perovskite layer is obtained by coating the hole transport layer with the solution described in any one of claims 1 to 6 and then annealing it. The annealing temperature is 80℃~150℃, the annealing time is 10~30min, and the annealing atmosphere is air or a non-reactive atmosphere; The inactive atmosphere is selected from at least one of nitrogen and inert gases.

10. The application according to claim 7, characterized in that, The substrate is selected from one of glass, metal plate, polyethylene terephthalate plastic, polyethylene naphthalate plastic, polyimide plastic and metal foil; The transparent conductive electrode comprises indium tin oxide or FTO; The hole transport layer comprises a self-assembled monolayer material, NiO. x At least one of CuI, Cu2O, 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene, 2,2',7,7'-tetratetra[N,N-di(4-tolyl)amino]-9,9'-spirodifluorene, N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine, and poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine]; The electron transport layer includes at least one of ZnO, TiO2, SnO2, methyl [6,6]-phenyl-C61-butyrate, and C60; The metal electrode layer includes at least one of Au, Ag, Cu, Al, Ni, Ti, and Cr; The modified passivation layer includes at least one of phenylethyl iodide, 1,3-propanediamine hydroiodate, magnesium fluoride, lithium fluoride, piperazine hydroiodate, and phenylethyl iodide bromide.

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