A perovskite solar cell and a preparation method thereof

Abstract

The present invention belongs to the technical field of solar cells, and provides a perovskite solar cell, comprising: a substrate; a first charge transport layer disposed on the surface of the substrate; a perovskite layer disposed on the surface of the first charge transport layer, wherein the perovskite layer contains 4-methylnicotine hydrochloride; a second charge transport layer disposed on the surface of the perovskite layer; and an electrode disposed on the surface of the second charge transport layer. In the present invention, 4-methylnicotine hydrochloride additive is introduced into the perovskite precursor, wherein N and O can act on the lead with low coordination, and Cl ions can passivate halogen defects, so that the perovskite crystallization quality is significantly improved and the trap state density is reduced.

Description

Technical Field

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

[0002] Perovskite solar cells have developed rapidly in the past decade due to their advantages such as high efficiency, low cost, and simple preparation, and have become the most commercially promising new photovoltaic technology. In perovskite solar cells, the perovskite absorption layer is crucial, and its quality directly affects the photoelectric conversion efficiency and stability of the entire cell. Therefore, improving the quality of the perovskite thin film, reducing the density of defect states in the film, and reducing non-radiative recombination are beneficial to improving the photoelectric conversion efficiency of the device. Summary of the Invention

[0003] In view of this, the purpose of the embodiments of the present invention is to provide a perovskite solar cell and a preparation method thereof. The perovskite solar cell provided by the present invention has good photoelectric conversion efficiency.

[0004] The present invention provides a perovskite solar cell, comprising:

[0005] A substrate;

[0006] A first charge transport layer disposed on the surface of the substrate;

[0007] A perovskite layer disposed on the surface of the first charge transport layer, and the perovskite layer contains 4-methylnicotine hydrochloride;

[0008] A second charge transport layer disposed on the surface of the perovskite layer;

[0009] An electrode disposed on the surface of the second charge transport layer.

[0010] Preferably, the perovskite layer further comprises a halide perovskite; the crystal structure of the halide perovskite is ABX3, A is selected from at least one of organic cations or inorganic cations, more preferably selected from at least one of formamidinium ions (FA), methylammonium ions (MA), cesium ions (Cs); B is selected from divalent metal ions, more preferably selected from at least one of lead ions (Pb), divalent tin ions (Sn); X is selected from halogen ions, more preferably selected from at least one of iodide ions (I), bromide ions (Br), chloride ions (Cl).

[0011] Preferably, the molar ratio of the 4-methylnicotine hydrochloride to the halide perovskite is (0.1% - 10%):1.

[0012] Preferably, the thickness of the perovskite layer is 200 - 500 nm.

[0013] Preferably, the electrode is selected from one or more of a metal electrode, a carbon electrode, and a transparent conductive oxide electrode; and the thickness is 50 to 150 nm.

[0014] Preferably, the material of the first charge transport layer is selected from one or more of TiO2, SnO2, NiO x , and PTAA; and the thickness is 10 to 40 nm.

[0015] Preferably, the material of the second charge transport layer is selected from one or more of Spiro-OMeTAD, PCBM, and C60; and the thickness is 50 to 300 nm.

[0016] The present invention provides a method for preparing a perovskite solar cell according to the above technical solution, including:

[0017] A substrate;

[0018] Preparing a first charge transport layer on the surface of the substrate;

[0019] Preparing a perovskite layer on the surface of the first charge transport layer;

[0020] Preparing a second charge transport layer on the surface of the perovskite layer;

[0021] Preparing an electrode on the surface of the second charge transport layer.

[0022] Preferably, the method for preparing the perovskite layer includes:

[0023] Coating a perovskite precursor solution on the surface of the first charge transport layer and then annealing to obtain a perovskite layer;

[0024] 4-Methylnicotine hydrochloride is added to the perovskite precursor solution.

[0025] Preferably, the annealing temperature is 100 to 200 °C; and the annealing time is 5 to 20 minutes.

[0026] The present invention provides a method for improving the performance of a perovskite solar cell, applying 4-methylnicotine hydrochloride to the perovskite solar cell to improve the performance of the perovskite solar cell. The present invention introduces a 4-methylnicotine hydrochloride additive into the perovskite precursor. N and O therein can act on lead with low coordination, and Cl ions can passivate halogen defects, significantly improving the crystallization quality of the perovskite and reducing the trap state density. By introducing an additive into the perovskite precursor, adjusting the crystallization process of the perovskite, and optimizing its crystal growth, the present invention can effectively improve the film quality. Description of the Drawings

[0027] Figure 1 Detection results of the battery performance prepared in Example 1;

[0028] Figure 2 Battery performance test results prepared for Example 2;

[0029] Figure 3 Battery performance test results prepared for Comparative Example 1;

[0030] Figure 4 Battery performance test results prepared for Comparative Example 2. Detailed implementation manners

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Apparently, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0032] The present invention provides a perovskite solar cell, comprising:

[0033] A substrate;

[0034] A first charge transport layer disposed on the surface of the substrate;

[0035] A perovskite layer disposed on the surface of the first charge transport layer, and the perovskite layer contains 4-methylnicotine hydrochloride;

[0036] A second charge transport layer disposed on the surface of the perovskite layer;

[0037] An electrode disposed on the surface of the second charge transport layer.

[0038] In the present invention, the material of the substrate is preferably selected from FTO transparent conductive glass or ITO transparent conductive glass; the sheet resistance of the substrate is preferably 7-15 Ω / sq –1 , more preferably 7 Ω / sq –1 .

[0039] In the present invention, the material of the first charge transport layer is preferably selected from one or more of TiO2, SnO2, NiO x , PTAA; the thickness of the first charge transport layer is preferably 10-40 nm, more preferably 20-30 nm, and most preferably 25 nm.

[0040] In the present invention, the composition of the perovskite layer preferably further includes halide perovskite, and the crystal structure (composition formula) of the halide perovskite is preferably ABX3; A is selected from at least one of organic cations or inorganic cations, and more preferably selected from at least one of formamidinium ion (FA), methylammonium ion (MA), cesium ion (Cs); B is selected from divalent metal ions, and more preferably selected from at least one of lead ion (Pb), divalent tin ion (Sn); X is selected from halide ions, and more preferably selected from at least one of iodide ion (I), bromide ion (Br), chloride ion (Cl).

[0041] In the present invention, the molar ratio of the 4-methylnicotine hydrochloride to the halide perovskite is preferably (0.01 - 0.10):1, more preferably (0.02 - 0.08):1, still more preferably (0.03 - 0.06):1, and most preferably (0.04 - 0.05):1.

[0042] In the present invention, the thickness of the perovskite layer is preferably 200 - 500 nm, more preferably 300 - 400 nm, and most preferably 350 nm.

[0043] In the present invention, the material of the second charge extraction layer is preferably selected from one or more of Spiro-OMeTAD, PCBM, C60; the thickness of the second charge transport layer is preferably 50 - 300 nm, more preferably 100 - 200 nm, and most preferably 150 nm.

[0044] In the present invention, the material of the electrode is preferably selected from one or more of metal electrodes, carbon electrodes, and transparent conductive oxide electrodes; the thickness of the electrode is preferably 50 - 150 nm, more preferably 80 - 120 nm, and most preferably 100 nm.

[0045] The present invention provides a method for preparing a perovskite solar cell according to the above technical solution, comprising:

[0046] a substrate;

[0047] preparing a first charge transport layer on the surface of the substrate;

[0048] preparing a perovskite layer on the surface of the first charge transport layer;

[0049] preparing a second charge transport layer on the surface of the perovskite layer;

[0050] preparing an electrode on the surface of the second charge transport layer.

[0051] In an embodiment of the present invention, the substrate may be an FTO glass substrate. The substrate can be cleaned successively with acetone, isopropyl alcohol, and deionized water, and after being dried, it is treated with ultraviolet-ozone. The treatment time can be 10 to 30 minutes, or it can also be 20 minutes.

[0052] In the present invention, the preparation method of the first charge transport layer is preferably selected from one or more of chemical bath deposition method, spray pyrolysis method, magnetron sputtering method, spin coating method, and atomic layer deposition method. Those skilled in the art can prepare it according to the conventional method for preparing the first charge transport layer. In an embodiment of the present invention, the preparation method of the first charge transport layer may include:

[0053] Put the substrate into the first charge transport layer precursor solution, and then take it out for drying, rinsing, and annealing to obtain the first charge transport layer.

[0054] In an embodiment of the present invention, the first charge transport layer precursor solution can be titanium tetrachloride solution. The preparation method of the titanium tetrachloride solution can be to drop titanium tetrachloride into ice water drop by drop. Drying can be carried out in an oven, and the drying temperature can be 60 to 80 °C, or it can also be 70 °C. The drying time can be 50 to 70 minutes, or it can also be 60 minutes. Rinsing can be carried out with deionized water and absolute ethanol until clean. The annealing temperature can be 160 to 200 °C, or it can also be 180 °C. The annealing time can be 20 to 40 minutes, or it can also be 30 minutes.

[0055] In the present invention, the preparation method of the perovskite layer preferably includes:

[0056] Coat the perovskite precursor solution on the surface of the first charge transport layer and then anneal to obtain the perovskite (light-absorbing) layer.

[0057] In the present invention, the perovskite precursor solution contains 4-methylnicotine hydrochloride. The perovskite precursor solution preferably includes a solute and a solvent. The solute includes a halide perovskite and 4-methylnicotine hydrochloride. The crystal structure of the halide perovskite is the same as that described in the above technical solution, and can be one or more of methylammonium iodide, cesium iodide, lead iodide, methylammonium chloride, dimethylamine hydroiodide, etc. The molar ratio of the halide perovskite and 4-methylnicotine hydrochloride is the same as that described in the above technical solution. The solvent is preferably selected from one or more of DMF (N,N-dimethylformamide) and DMSO (dimethyl sulfoxide). The molar concentration of the perovskite precursor solution is preferably 0.5 to 1.5 mol / L, and more preferably 0.6 to 0.8 mol / L.

[0058] In the present invention, the annealing temperature is preferably 100 - 200 °C, more preferably 120 - 180 °C, and most preferably 140 - 160 °C; the annealing time is preferably 5 - 20 minutes, more preferably 10 - 15 minutes.

[0059] In an embodiment of the present invention, the method for preparing the perovskite layer may include:

[0060] Spin-coating the perovskite precursor solution on the surface of the first charge transport layer, then adding an anti-solvent, and then annealing to obtain the perovskite layer.

[0061] In an embodiment of the present invention, the solutes in the perovskite precursor solution may include: FAI, PbI2, MACl, and 4-methylnicotine hydrochloride; the molar ratio of PbI2 to FAI may be (0.8 - 1.2):1 or 1:1; the molar ratio of MACl to PbI2 may be (0.3 - 0.4):1 or 0.35:1; the molar ratio of 4-methylnicotine hydrochloride to PbI2 may be (0.008 - 0.012):1 or 0.01:1; the concentration of the perovskite precursor solution may be 1 - 2 mol / L or 1.4 mol / L; the solvent in the perovskite precursor solution may include DMF and DMSO; the volume ratio of DMF to DMSO may be (8 - 10):1 or 9:1.

[0062] In an embodiment of the present invention, the speed during spin-coating for preparing the perovskite layer may be 4000 - 6000 rpm or 5000 rpm; the spin-coating time may be 10 - 20 s or 15 s; the anti-solvent may be added at the 10th second; the anti-solvent may be anhydrous ether; the annealing temperature may be 100 - 200 °C or 150 °C; the annealing time may be 15 - 25 minutes or 20 minutes.

[0063] In the present invention, the method for preparing the second charge transport layer is preferably selected from one or more of spin-coating, sputtering, and vacuum evaporation; those skilled in the art can prepare the second charge transport layer according to the conventional method for preparing the second charge transport layer. In an embodiment of the present invention, the method for preparing the second charge transport layer may include:

[0064] Spin-coating the second charge transport layer precursor solution on the surface of the perovskite layer to obtain the second charge transport layer.

[0065] In an embodiment of the present invention, the method for preparing the second charge transport layer precursor solution may include: dissolving 72 mg of Spiro-OMeTAD and 39 μL of 4-tert-butylpyridine in 1 mL of chlorobenzene, and adding 23 μL of 520 mg / mL -1An acetonitrile solution of lithium bis(trifluoromethanesulfonyl)imide. In the embodiments of the present invention, the speed during spin coating in the process of preparing the second charge transport layer can be 2000 - 4000 rpm, or can be 3000 rpm; the spin coating time can be 20 - 40 s, or can be 30 s.

[0066] In the present invention, the preparation method of the electrode is preferably selected from sputtering, vacuum evaporation, and spin coating; those skilled in the art can prepare the electrode according to the conventional method for preparing electrodes. In the embodiments of the present invention, when preparing the electrode by vacuum evaporation, the vacuum degree can be lower than 10-4 Pa, and the deposition rate can be can also be

[0067] In the present invention, 4-methylnicotine hydrochloride additive is introduced into the perovskite precursor. The N and O therein can act on the lead with low coordination, and the Cl ions can passivate the halogen defects, significantly improving the crystallization quality of the perovskite and reducing the trap state density. By introducing additives into the perovskite precursor, adjusting the crystallization process of the perovskite, and optimizing its crystal growth, the present invention can effectively improve the film quality.

[0068] Example 1

[0069] Clean the FTO glass substrate successively with acetone, isopropanol, and deionized water, and after drying, treat it with ultraviolet-ozone for 20 minutes. Drop 4.5 mL of titanium tetrachloride into 200 mL of ice water drop by drop, mix evenly to prepare a titanium tetrachloride solution, put the FTO glass into the titanium tetrachloride solution, place it in an oven at 70 °C for 60 minutes, take it out, rinse it with deionized water and absolute ethanol, and anneal it at 180 °C for 30 minutes. Prepare a FAPbI3 perovskite precursor solution in a nitrogen glove box (the solutes in the perovskite precursor solution are FAI, PbI2, MACl, and 4-methylnicotine hydrochloride, the molar ratio of PbI2 to FAI is 1:1, the molar ratio of MACl to PbI2 is 0.35:1, and the molar ratio of 4-methylnicotine hydrochloride to PbI2 is 0.01:1), with a concentration of 1.4 mol / L, and the solvent is a mixed solution of DMF and DMSO with a volume ratio of 9:1. Take 50 μL of the perovskite precursor solution and drop it on the titanium dioxide layer, spin coat it at 5000 rpm for 15 s, and add 150 μL of absolute ether at the 10th s, and anneal it at 150 °C for 20 minutes. Dissolve 72 mg of Spiro-OMeTAD and 39 μL of 4-tert-butylpyridine in 1 mL of chlorobenzene, add 23 μL of a -1 solution of lithium bis(trifluoromethanesulfonyl)imide in acetonitrile, mix evenly, and spin coat it on the perovskite layer at 3000 rpm for 30 s; finally, prepare a silver electrode by vacuum evaporation, with a vacuum degree lower than 10 -4 Pa, and the deposition rate A perovskite solar cell is obtained.

[0070] In the perovskite solar cell prepared in Example 1 of the present invention, the first charge transport layer is 20 nm, the perovskite layer is 400 nm, the second charge transport layer is 200 nm, and the silver electrode is 70 nm.

[0071] Example 2

[0072] The FTO glass substrate was successively cleaned with acetone, isopropanol, and deionized water, and after drying, it was treated with ultraviolet-ozone for 20 minutes. 4.5 mL of titanium tetrachloride was gradually added dropwise to 200 mL of ice water, and the mixture was stirred evenly to prepare a titanium tetrachloride solution. The FTO glass was placed in the titanium tetrachloride solution and placed in an oven at 70 °C for 60 minutes. After taking it out, it was rinsed clean with deionized water and absolute ethanol, and annealed at 180 °C for 30 minutes. A CsPbI3 perovskite precursor solution was prepared in a nitrogen glove box (the solutes in the perovskite precursor solution are CsI, PbI2, DMAI, and 4-methylnicotine hydrochloride, with a molar ratio of 1:1:1:0.01 and a concentration of 0.8 mol / L, and the solvent is DMF); 50 μL of the perovskite precursor solution was dropped on the titanium dioxide layer and spin-coated at 4000 rpm for 30 s, and annealed at 200 °C for 5 minutes. 72 mg of Spiro-OMeTAD and 39 μL of 4-tert-butylpyridine were dissolved in 1 mL of chlorobenzene, and 23 μL of a -1 acetonitrile solution of lithium bis(trifluoromethanesulfonyl)imide with a concentration of 520 mg / mL was added and mixed evenly, and spin-coated at 3000 rpm for 30 s on the perovskite layer; finally, a silver electrode was prepared by vacuum evaporation, and the vacuum degree was lower than 10 -4 Pa, and the deposition rate A perovskite solar cell is obtained.

[0073] In the perovskite solar cell prepared in Example 2 of the present invention, the electron transport layer is 20 nm, the perovskite layer is 400 nm, the hole transport layer is 200 nm, and the silver electrode is 70 nm.

[0074] Comparative Example 1

[0075] A perovskite solar cell was prepared according to the method of Example 1. The difference from Example 1 is that 4-methylnicotine hydrochloride was not added to the perovskite precursor solution.

[0076] Comparative Example 2

[0077] A perovskite solar cell was prepared according to the method of Example 2. The difference from Example 2 is that 4-methylnicotine hydrochloride was not added to the perovskite precursor solution.

[0078] Performance detection

[0079] Under room temperature conditions, using a 3A solar simulator, at a light intensity of 100 mW / cm 2 , the photoelectric conversion efficiency of the cells prepared in the examples and comparative examples was tested. The effective area of the cells was 0.09 cm 2 . The test data are as Figures 1 to 4 shown. The short-circuit current density of the cell prepared in Example 1 was 25.55 mA / cm 2 , the open-circuit voltage was 1.089 V, the fill factor was 78.72%, and the photoelectric conversion efficiency was 21.91%; the short-circuit current density of the cell prepared in Example 2 was 19.47 mA / cm 2 , the open-circuit voltage was 1.133 V, the fill factor was 80.46%, and the photoelectric conversion efficiency was 17.75%; the short-circuit current density of the cell prepared in Comparative Example 1 was 25.71 mA / cm 2 , the open-circuit voltage was 1.068 V, the fill factor was 74.59%, and the photoelectric conversion efficiency was 20.48%; the short-circuit current density of the cell prepared in Comparative Example 2 was 19.12 mA / cm 2 , the open-circuit voltage was 1.091 V, the fill factor was 80.45%, and the photoelectric conversion efficiency was 16.79%.

[0080] In the present invention, 4-methylnicotine hydrochloride additive is introduced into the perovskite precursor. The N and O therein can act on the low-coordinated lead, and the Cl ions can passivate the halogen defects, significantly improving the perovskite crystallization quality and reducing the trap state density. By introducing an additive into the perovskite precursor, adjusting the crystallization process of the perovskite, and optimizing its crystal growth, the present invention can effectively improve the film quality.

[0081] Although the present invention has been described and illustrated with reference to specific embodiments thereof, such description and illustration do not limit the present invention. Those skilled in the art can clearly understand that various changes can be made without departing from the true spirit and scope of the present invention as defined by the appended claims, so as to adapt a specific situation, material, composition of matter, substance, method or process to the objectives, spirit and scope of the present application. All such modifications are intended to be within the scope of the appended claims. Although the methods disclosed herein have been described with reference to specific operations performed in a specific order, it should be understood that these operations can be combined, subdivided or reordered without departing from the teachings of the present invention to form equivalent methods. Therefore, unless specifically indicated herein, the order and grouping of operations are not limitations of the present application.

Claims

1. A perovskite solar cell, characterized in that include: substrate; A first charge transport layer disposed on the surface of the substrate; A perovskite layer disposed on the surface of the first charge transport layer, the perovskite layer containing 4-methylnicotine hydrochloride; the perovskite layer further comprising: a halide perovskite; the molar ratio of the 4-methylnicotine hydrochloride to the halide perovskite being (0.1% to 10%):1; a second charge transport layer disposed on the surface of the perovskite layer; An electrode is provided on the surface of the second charge transport layer.

2. The perovskite solar cell according to claim 1, characterized in that The thickness of the perovskite layer is 200-500 nm.

3. The perovskite solar cell according to claim 1, characterized in that The material of the first charge transport layer is selected from one or more of titanium dioxide, tin dioxide, NiOx, and PTAA; and the thickness is 10-40 nm.

4. The perovskite solar cell according to claim 1, wherein The material of the second charge transport layer is selected from one or more of Spiro-OMeTAD, PCBM, and C60; and the thickness is 50-300 nm.

5. The perovskite solar cell according to claim 1, wherein The electrode is selected from one or more of a metal electrode, a carbon electrode, and a transparent conductive oxide electrode; and has a thickness of 50 to 150 nm.

6. A method for preparing a perovskite solar cell according to claim 1, characterized in that: include: substrate; preparing a first charge transport layer on the surface of the substrate; preparing a perovskite layer on the surface of the first charge transport layer; preparing a second charge transport layer on the surface of the perovskite layer; An electrode is prepared on the surface of the second charge transport layer.

7. The preparation method according to claim 6, characterized in that The preparation method of the perovskite layer comprises: coating a perovskite precursor solution on the surface of the first charge transport layer and then annealing to obtain a perovskite layer; 4-Methylnicotine hydrochloride is added to the perovskite precursor solution.

8. The preparation method according to claim 7, characterized in that The annealing temperature is 100-200° C.; the annealing time is 5-20 minutes.

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