Perovskite precursor solution, perovskite solar cell and preparation method thereof

Abstract

The invention belongs to the field of solar cells, and particularly discloses a perovskite precursor solution, a perovskite solar cell and a preparation method of the perovskite solar cell. According to the invention, poly (acrylonitrile-ethyl acrylic acid) exists in the perovskite precursor solution, and the poly (acrylonitrile-ethyl acrylic acid) can improve the crystal quality of the perovskite light absorption layer, so as to improve the photoelectric conversion efficiency and fill factor of the perovskite cell.

Description

Technical Field

[0001] The present invention belongs to the field of solar cells, and in particular relates to a perovskite precursor solution, a perovskite solar cell and a preparation method thereof. Background Art

[0002] Halogenated formamidine (FA)-based perovskite materials have excellent photovoltaic properties, especially their broad absorption spectra, and have attracted widespread attention. Among them, the photoelectric conversion efficiency of trans-structured fluoroformamidine (FA)-based perovskite cells has exceeded 20%. However, during the crystallization process of the perovskite precursor solution to form the halogenated formamidine (FA)-based perovskite material film, multiple intermediate phases exist. The intermediate phases can crystallize into non-photoactive crystalline phases and photoactive crystalline phases (such as α phase). However, the nucleation pathways of each intermediate phase are different, and the transformation between the crystalline phases is complex and difficult to control. This leads to a large number of non-photoactive crystalline phases, poor crystallization quality of the overall film, and imbalanced electron-hole transport properties, making it difficult to further significantly improve the efficiency of the solar cell assembled from them. Summary of the Invention

[0003] In response to the problem of low efficiency of the above-mentioned prior art haloformamidine (FA)-based perovskite solar cells, the present invention provides a perovskite precursor solution, a perovskite solar cell and a preparation method thereof.

[0004] To achieve the above objectives, the following technical solutions are specifically included:

[0005] In the first aspect, the present invention provides a perovskite precursor solution, comprising a perovskite precursor component, poly (acrylonitrile-2-ethyl acrylic acid) and an organic solvent; the perovskite precursor component comprises formamidinium, Pb 2+ and I - .

[0006] Poly(acrylonitrile-2-ethylacrylate) exists in the perovskite precursor solution. When the perovskite light-absorbing layer is prepared by the perovskite precursor solution, the poly(acrylonitrile-2-ethylacrylate) in the perovskite precursor solution and PbI2 construct an intermediate to regulate the α-oriented crystal growth of the FA-containing perovskite and simultaneously control the nucleation of the perovskite phase, thereby achieving the purpose of improving the uniformity and crystallinity of the haloformamidine (FA)-based perovskite film, thereby improving the efficiency of the perovskite battery assembled therefrom.

[0007] Poly(acrylonitrile-2-ethylacrylate) is represented by the following formula I:

[0008] [-CH2-C(CN)-] m [-CH2-C(COOH)(C2H5)-] n Formula I;

[0009] wherein m is the number of acrylonitrile units, n is the number of 2-ethyl acrylic acid units, and m and n are each independently selected from 1-99.

[0010] In some embodiments, the ratio of m to n is (70-85):(25-30).

[0011] In some embodiments, the preparation method of poly(acrylonitrile-2-ethylacrylic acid) comprises the following steps: dissolving acrylonitrile and 2-ethylacrylic acid in a solvent to obtain a monomer solution; adding an initiator to the monomer solution and performing a polymerization reaction at 60-70° C. to obtain poly(acrylonitrile-2-ethylacrylic acid).

[0012] In some embodiments, the solvent includes at least one of N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO) or a mixed solvent of methanol and water, the initiator includes at least one of azobisisobutyronitrile (AIBN) or benzoyl peroxide (BPO), and the added amount of the initiator is 0.5%-2% of the total mass of acrylonitrile and 2-ethyl acrylic acid.

[0013] In some embodiments, in the perovskite precursor solution, the concentration of the poly(acrylonitrile-2-ethylacrylate) is 30-50 mol / L, specifically, 30 mol / L, 32 mol / L, 34 mol / L, 36 mol / L, 38 mol / L, 40 mol / L, 42 mol / L, 44 mol / L, 46 mol / L, 48 mol / L, 50 mol / L, or a range consisting of any two of these values. The concentration of poly(acrylonitrile-2-ethylacrylate) affects its ability to regulate the crystallization quality of the perovskite film. Within the above concentration range, the efficiency of the perovskite cell is higher.

[0014] In some embodiments, the molar ratio of the amidino group to poly(acrylonitrile-2-ethylacrylic acid) is 1:(40-75), more preferably 1:(57-67), and more specifically, it can be 1:40, 1:45, 1:50, 1:55, 1:60, 1:65, 1:70, 1:75, or a range consisting of any two of these values.

[0015] In some embodiments, the chemical formula of the perovskite precursor component is ABX3, where A is a formamidino group (FA + ) or formamidinyl (FA + ) and methylamine ion (MA + ), B is Pb 2+ or Pb 2+ and Sn 2+ , X is Cl - Br -or I - At least one of .

[0016] In some embodiments, in the perovskite precursor solution, the concentration of the perovskite precursor component is 0.1-1 mol / L, specifically, it can be 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1 mol / L, or a range consisting of any two of these values.

[0017] In some embodiments, in the perovskite precursor solution, the concentration of the formamidinium group is 0.6-0.8 mol / L, specifically, it can be 0.6 mol / L, 0.65 mol / L, 0.7 mol / L, 0.75 mol / L, 0.8 mol / L, or a range consisting of any two of these values.

[0018] In some embodiments, the perovskite precursor components are composed of FAI, MAI, PbI2, and PbBr2. In the perovskite precursor solution, the concentration of PbI2 is 0.4-0.6 mol / L, specifically, it can be 0.4 mol / L, 0.45 mol / L, 0.5 mol / L, 0.55 mol / L, 0.6 mol / L, or a range consisting of any two of these values.

[0019] In some embodiments, the molar ratio of FAI to MAI is (0.6-0.8): (0.2-0.4), the molar ratio of PbI2 to PbBr2 is (0.4-0.6): (0.4-0.6), and FA + and MA + The total molar amount of Pb 2+ The molar amount of I - and Br - The total molar ratio is 1:1:3.

[0020] In some embodiments, the Pb 2+ The molar ratio of the benzophenone to the carbamimidyl group is 1:(0.5-0.9), specifically, it can be 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, or a range consisting of any two of these values.

[0021] In some embodiments, the organic solvent includes at least one of DMF or DMSO.

[0022] Preferably, the organic solvent comprises DMF and DMSO, and the volume ratio of DMF to DMSO is (3-5):1.

[0023] In a second aspect, the present invention provides a perovskite solar cell, comprising a substrate, a top transparent conductive layer, a hole transport layer, a perovskite light absorbing layer, a first electron transport layer, a second electron transport layer, a bottom transparent conductive layer and an electrode layer stacked in sequence, wherein the perovskite light absorbing layer is prepared from the perovskite precursor solution.

[0024] In some embodiments, the thickness of the substrate is 1.1-3.2 mm, and the substrate comprises a glass substrate.

[0025] In some embodiments, the top transparent conductive layer includes at least one of FTO or ITO.

[0026] In some embodiments, the thickness of the top transparent conductive layer is 450-600 nm, specifically 450 nm, 460 nm, 470 nm, 480 nm, 490 nm, 500 nm, 510 nm, 520 nm, 530 nm, 540 nm, 550 nm, 560 nm, 570 nm, 580 nm, 590 nm, 600 nm, or a range consisting of any two of these values. FTO refers to fluorine-doped tin oxide, and ITO refers to tin-doped indium oxide. For example, tin-doped indium oxide having a mass ratio of indium to tin of 90:10 can be used.

[0027] In some embodiments, the thickness of the hole transport layer is 10-30 nm, specifically, it can be 10 nm, 12 nm, 14 nm, 16 nm, 18 nm, 20 nm, 22 nm, 24 nm, 26 nm, 28 nm, 30 nm, or a range consisting of any two of these values.

[0028] In some embodiments, the hole transport layer includes at least one of a NiO layer or a zinc-doped nickel oxide layer.

[0029] In some embodiments, the mass ratio of Ni to Zn elements in the zinc-doped nickel oxide layer is (98-99.5): (0.5-2).

[0030] In some embodiments, the thickness of the perovskite light absorbing layer is 300-500 nm, specifically, it can be 300 nm, 325 nm, 350 nm, 375 nm, 400 nm, 425 nm, 450 nm, 475 nm, 500 nm, or a range consisting of any two of these values.

[0031] In some embodiments, the thickness of the first electron transport layer is 20-40 nm, specifically, it can be 30 nm, 31 nm, 32 nm, 33 nm, 34 nm, 35 nm, 36 nm, 37 nm, or a range consisting of any two of these values.

[0032] In some embodiments, the first electron transport layer comprises C 60 layer.

[0033] In some embodiments, the thickness of the second electron transport layer is 5-15 nm, specifically, it can be 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, or a range consisting of any two of these values.

[0034] In some embodiments, the second electron transport layer includes a BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) layer, which has the function of electron transport and also has the function of blocking holes, thereby improving the electron transport efficiency and the photoelectric conversion efficiency of the battery.

[0035] In some embodiments, the bottom transparent conductive layer has a thickness of 150-200 nm, specifically, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm, 200 nm, or a range consisting of any two of these values.

[0036] In some embodiments, the bottom transparent conductive layer includes an aluminum-doped zinc oxide layer, wherein the mass ratio of Zn to Al in the aluminum-doped zinc oxide layer is (98-99.5): (0.5-2). The aluminum-doped zinc oxide layer has high electron mobility, good stability, and high conductivity, which helps improve the photoelectric conversion efficiency of the battery.

[0037] In some embodiments, the thickness of the electrode layer is 30-50 nm, specifically, it can be 30 nm, 32 nm, 34 nm, 36 nm, 38 nm, 40 nm, 42 nm, 44 nm, 46 nm, 48 nm, 50 nm, or a range consisting of any two of these values.

[0038] In some embodiments, the electrode layer includes at least one of a copper electrode layer or a silver electrode layer.

[0039] In a third aspect, the present invention provides a method for preparing the perovskite solar cell, comprising the following steps:

[0040] (1) depositing a top transparent conductive layer and a hole transport layer on a substrate in sequence by magnetron sputtering;

[0041] (2) coating the perovskite precursor solution on the hole transport layer and annealing to obtain a perovskite light absorbing layer;

[0042] (3) depositing a first electron transport layer on the perovskite light absorbing layer by an evaporation method;

[0043] (4) depositing a second electron transport layer on the first electron transport layer by an evaporation method;

[0044] (5) depositing a bottom transparent conductive layer on the second electron transport layer by magnetron sputtering;

[0045] (6) Depositing an electrode layer on the bottom transparent conductive layer by magnetron sputtering to obtain the perovskite solar cell.

[0046] In some embodiments, in steps (1), (5) and (6), the magnetron sputtering method is independently selected from the following process parameters: sputtering power of 5-30KW, coating speed of 5-15mm / s, voltage of 200-400V, specifically, the sputtering power can be 5KW, 8KW, 11KW, 14KW, 17KW, 21KW, 24KW, 27KW, 30KW, or a range consisting of any two of these values; the coating speed can be 5mm / s, 6mm / s, 7mm / s, 8mm / s, 9mm / s, 10mm / s, 11mm / s, 12mm / s, 13mm / s, 14mm / s, 15mm / s, or a range consisting of any two of these values; the voltage can specifically be 200V, 220V, 240V, 260V, 280V, 300V, 320V, 340V, 360V, 380V, 400V, or a range consisting of any two of these values.

[0047] In some embodiments, in step (2), the annealing temperature is 60-80°C, specifically, it can be 60°C, 62°C, 64°C, 66°C, 68°C, 70°C, 72°C, 74°C, 76°C, 78°C, 80°C, or a range consisting of any two of these values.

[0048] In some embodiments, in step (2), the annealing time is 10-30 s, specifically, it can be 10 s, 12 s, 14 s, 16 s, 18 s, 20 s, 22 s, 24 s, 26 s, 28 s, 30 s, or a range consisting of any two of these values.

[0049] In some embodiments, in step (2), the coating method is independently selected from at least one of blade coating, spin coating, slit coating or spray coating.

[0050] In some embodiments, in step (3), in the evaporation method, the temperature of the evaporation source is 300-350°C.

[0051] In some embodiments, in step (4), in the evaporation method, the temperature of the evaporation source is 150-180°C.

[0052] Compared with the prior art, the present invention has the following beneficial effects: the present invention uses a perovskite precursor solution containing poly(acrylonitrile-2-ethylacrylic acid) to coat crystals to prepare a perovskite light-absorbing layer, which can improve the crystallization quality of the haloformamidine-based perovskite material, thereby improving the efficiency of the perovskite cell assembled from the perovskite light-absorbing layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 This is a scanning electron microscope (SEM) image of the perovskite light-absorbing layer in Example 1. DETAILED DESCRIPTION

[0054] To better illustrate the objectives, technical solutions, and advantages of the present invention, the present invention will be further described below with reference to specific examples. The experimental methods used in the examples and / or comparative examples are conventional methods unless otherwise specified; the materials and reagents used are commercially available unless otherwise specified.

[0055] (1) The following poly(acrylonitrile-2-ethylacrylic acid) was prepared by self-production, and the self-production method specifically comprises the following steps:

[0056] S1. Acrylonitrile (AN, CAS: 107-13-1) and 2-ethylacrylic acid (2-EAA, CAS: 3586-58-1) are mixed in a desired molar ratio of 80:20 mol%, and the mixed materials are dissolved in DMF solvent to obtain a monomer solution;

[0057] S2. Under nitrogen protection, the monomer solution was heated to 65°C, and azobisisobutyronitrile (AIBN) was added in an amount of 1 wt% of the total mass of AN and 2-EAA. The polymerization reaction was maintained at the temperature for 12 hours, and then the temperature was cooled to room temperature. Methanol was added to precipitate the copolymer, which was filtered and dried in vacuo at 60°C to obtain poly(acrylonitrile-2-ethylacrylic acid).

[0058] (2) Polyacrylonitrile: CAS: 25014-41-9, commercially available.

[0059] (3) Polymethyl methacrylate: CAS: 9010-88-2, commercially available.

[0060] Example 1

[0061] A method for preparing a perovskite solar cell comprises the following steps:

[0062] (1) A 500 nm thick ITO film was deposited on 2 mm thick white glass using a magnetron sputtering method; wherein, the total power of the magnetron sputtering was 30 kW, the magnetron sputtering coating speed was 10 mm / s, the voltage was 350 V, and the target material was an ITO target material with an indium:tin atomic mass ratio of 90:10;

[0063] (2) depositing a zinc-doped nickel oxide layer on the ITO film layer by magnetron sputtering with a thickness of 20 nm; wherein the magnetron sputtering power is 6 kW, the magnetron sputtering coating speed is 10 mm / s, the voltage is 300 V, the target material is a NiZnO target, and the atomic mass ratio of Ni to Zn in the NiZnO target is 99:1;

[0064] (3) A mixed solvent of DMF (C3H7NO) and DMSO (C2H6OS) was prepared in a volume ratio of 4:1, and poly(acrylonitrile-2-ethyl acrylic acid) was added to make the concentration of poly(acrylonitrile-2-ethyl acrylic acid) 40 mol / L to obtain a mixed solution; FAI (CH5IN2), MAI (CH3NH2·HI), PbBr2 and PbI2 were weighed respectively and added to the above mixed solution, stirred at 50°C for 2 h, and then filtered with 0.22 μm PTFE (polytetrafluoroethylene) to obtain a perovskite precursor solution, wherein the concentrations of FAI and PbI2 in the perovskite precursor solution were 0.7 mol / L and 0.5 mol / L, respectively, and the concentrations of the remaining substances were shown in Table 1; the perovskite precursor solution was scraped onto the zinc-doped nickel oxide layer and annealed under nitrogen at 65°C for 10 s to obtain a perovskite light-absorbing layer with a thickness of 400 nm;

[0065] (4) Using the evaporation method to deposit a layer of C on the perovskite light absorbing layer 60 layer, the film thickness is 20nm, and the temperature of the evaporation source is 350℃;

[0066] (5) Using the evaporation method on C 60 A BCP layer was deposited on the layer, the temperature of the evaporation source was 150 ° C, and the film thickness was 10 nm;

[0067] (6) depositing a ZnOAl layer on the BCP layer by magnetron sputtering, with a film thickness of 180 nm, wherein the magnetron sputtering power is 20 kW, the magnetron sputtering coating speed is 10 mm / s, the voltage is 400 V, the target material is a zinc oxide aluminum target, and the atomic mass ratio of Zn to Al in the zinc oxide aluminum target is 98:2;

[0068] (7) A Cu film layer was deposited on the ZnOAl film layer by magnetron sputtering as an electrode layer with a thickness of 40 nm, wherein the magnetron sputtering power was 8 kW, the magnetron sputtering coating speed was 10 mm / s, the voltage was 250 V, and the target material was Cu; thus, a perovskite thin film solar cell was obtained.

[0069] Example 2-3

[0070] Compared with Example 1, Example 2-3 differs in that the concentrations of FAI and MAI are different, as shown in Table 1, and the rest are the same.

[0071] Examples 4-5

[0072] Compared with Example 1, Example 4-5 differs in that the concentrations of PbI2 and PbBr2 are different, as shown in Table 1, and the rest are the same.

[0073] Examples 6-7

[0074] Compared with Example 1, Example 6-7 differs in that the concentration of poly(acrylonitrile-2-ethylacrylic acid) is different, as shown in Table 1, and the rest are the same.

[0075] Comparative Example 1

[0076] Compared with Example 1, in this comparative example, the perovskite precursor solution lacks poly(acrylonitrile-2-ethylacrylate), and the rest is the same.

[0077] Comparative Example 2

[0078] Compared with Example 1, in this comparative example, the perovskite precursor solution lacks poly(acrylonitrile-2-ethylacrylate) and is replaced by an equimolar amount of polyacrylonitrile, and the rest are the same.

[0079] Comparative Example 3

[0080] Compared with Example 1, in this comparative example, the perovskite precursor solution lacks poly(acrylonitrile-2-ethylacrylic acid) and is replaced by an equimolar amount of polymethyl methacrylate, and the rest are the same.

[0081] Performance test: The current density-voltage (JV) curves of the perovskite cells of the embodiment and the comparative example were tested using an IVS-KA6000 device, wherein the tested light intensity was 1000 W / m 2 , using AM 1.5G spectrum, temperature at 25℃, controlled in a low humidity environment, the photoelectric conversion efficiency (PCE, %) and fill factor (the ratio of battery output power to maximum theoretical power FF, %) were determined from the obtained current density-voltage (JV) curve to measure the photoelectric conversion efficiency and output efficiency of the battery.

[0082] After the perovskite light absorbing layer was prepared, the microscopic morphology of the perovskite light absorbing layer of Example 1 was tested by SEM. The results were as follows: Figure 1 As shown, it can be observed that the grain size in the perovskite light absorbing layer is large, the grains are complete and relatively uniform.

[0083] The test results are shown in Table 1.

[0084] Table 1

[0085]

[0086] It can be seen from the above embodiments that the PCE of the perovskite solar cell of the present invention reaches more than 18%, and the FF reaches more than 69%, which has excellent cell efficiency.

[0087] Comparison between Comparative Examples 1-3 and Example 1 shows that the presence of poly(acrylonitrile-2-ethylacrylic acid) in the perovskite precursor solution can improve the crystallization quality of the perovskite light-absorbing layer, thereby achieving the purpose of comprehensively improving the photoelectric conversion efficiency and fill factor of the perovskite cell.

[0088] It can be seen from Examples 1-3 that changes in the concentrations of poly(acrylonitrile-2-ethylacrylic acid), FAI, and PbI2 have a certain impact on the PCE and FF of perovskite cells.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A perovskite precursor solution, characterized in that The invention comprises a perovskite precursor component, poly (acrylonitrile-2-ethyl acrylic acid) and an organic solvent; the perovskite precursor component comprises formamidine, Pb 2+ and I - .

2. The perovskite precursor solution according to claim 1, wherein In the perovskite precursor solution, the concentration of poly(acrylonitrile-2-ethylacrylic acid) is 30-50 mol / L.

3. The perovskite precursor solution according to claim 1, wherein Include at least one of the following items: I. The chemical formula of the perovskite precursor component is ABX3, where A is a formamidine group or a formamidine group and a methylamine ion, and B is Pb 2+ or Pb 2+ and Sn 2+ , X is Cl - Br - or I - At least one of; II. In the perovskite precursor solution, the concentration of the perovskite precursor component is 0.1-1 mol / L; III. The organic solvent comprises at least one of DMF or DMSO; IV. The organic solvent includes DMF and DMSO, and the volume ratio of DMF to DMSO is (3-5):

1.

4. The perovskite precursor solution according to claim 1, wherein In the perovskite precursor solution, the concentration of the formamidinium group is 0.6-0.8 mol / L.

5. The perovskite precursor solution according to claim 1, wherein The perovskite precursor components are composed of FAI, MAI, PbI2, and PbBr2. In the perovskite precursor solution, the concentration of PbI2 is 0.4-0.6 mol / L.

6. A perovskite solar cell, characterized in that: The invention comprises a substrate, a top transparent conductive layer, a hole transport layer, a perovskite light absorbing layer, a first electron transport layer, a second electron transport layer, a bottom transparent conductive layer and an electrode layer stacked in sequence, wherein the perovskite light absorbing layer is prepared from the perovskite precursor solution according to any one of claims 1 to 5.

7. The perovskite solar cell according to claim 6, wherein The thickness of the perovskite light-absorbing layer is 300-500 nm.

8. The perovskite solar cell according to claim 6, wherein Include at least one of the following AJ: A. The thickness of the substrate is 1.1-3.2 mm, and the top transparent conductive layer includes at least one of FTO or ITO; B. The thickness of the hole transport layer is 10-30 nm; C. The hole transport layer comprises at least one of a NiO layer or a zinc-doped nickel oxide layer; D. The thickness of the first electron transport layer is 20-40 nm; E. The first electron transport layer includes C 60 layer; F. The thickness of the second electron transport layer is 5-15 nm; G. The second electron transport layer includes BCP; H. The thickness of the bottom transparent conductive layer is 150-200 nm; I. The bottom transparent conductive layer includes an aluminum-doped zinc oxide layer; J. The thickness of the electrode layer is 30-50 nm.

9. A method for preparing a perovskite solar cell according to any one of claims 6 to 8, characterized in that: The steps include: (1) depositing a top transparent conductive layer and a hole transport layer on a substrate in sequence by magnetron sputtering; (2) coating the perovskite precursor solution on the hole transport layer and annealing to obtain a perovskite light absorbing layer; (3) depositing a first electron transport layer on the perovskite light absorbing layer by an evaporation method; (4) depositing a second electron transport layer on the first electron transport layer by an evaporation method; (5) depositing a bottom transparent conductive layer on the second electron transport layer by magnetron sputtering; (6) Depositing an electrode layer on the bottom transparent conductive layer by magnetron sputtering to obtain the perovskite solar cell.

10. The method for preparing a perovskite solar cell according to claim 9, wherein: Include at least one of the following KMs: K. In steps (1), (5) and (6), in the magnetron sputtering method, the process parameters are independently selected from the following: sputtering power of 5-30KW, coating speed of 5-15mm / s, and voltage of 200-400V; L. In step (3), in the evaporation method, the temperature of the evaporation source is 300-350°C; M. In step (4), in the evaporation method, the temperature of the evaporation source is 150-180°C.

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