Perovskite solar cell passivation method and perovskite solar cell

Abstract

The invention provides a passivation method of a perovskite solar cell and the perovskite solar cell. The passivation method of the perovskite solar cell comprises the following steps: passivating the perovskite solar cell by using a multi-component passivation system; wherein the multi-component passivation system comprises a passivator containing double amino groups and iodide ions; a passivator containing a benzene ring and an amino group; the invention relates to a passivator containing piperazine rings and iodide ions. Through the synergistic effect of the ternary passivating agent, crystal defects are better passivated, energy level matching is improved, and cell interface filling is better, so that the series resistance of the solar device is lower, and the open-circuit voltage is higher.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of solar cells, in particular to a passivation method of perovskite solar cells and a perovskite solar cell. BACKGROUND

[0002] In recent years, perovskite solar cells have attracted extensive attention and research due to the low carrier recombination probability and high carrier mobility of perovskite materials.

[0003] In existing perovskite solar cells, there are a large number of defect states on the surface and grain boundaries of the perovskite thin film, such as iodine vacancies of point defects. As a defect state, iodine vacancies become carrier trapping centers, resulting in serious non-radiative recombination such as Shockley-Read-Hall (SRH) recombination, Auger recombination, and defect-assisted tunneling recombination, which leads to a much lower open-circuit voltage under vacancy defects than the theoretical value, affecting the device efficiency.

[0004] The current single passivation method has limited effect on multi-dimensional defect repair. The energy level mismatch problem of the electron transport layer / perovskite interface in the transverse structure device is prominent, resulting in a high interface energy level barrier (E>0.3eV). The interface energy level mismatch causes the quasi-Fermi level of the perovskite to be compressed, and the Voc is proportional to the band gap, so the actual Voc is much lower than the theoretical limit. For example, the theoretical Voc of a narrow-band perovskite (Eg=1.3eV) is 1.0V, but the interface barrier can reduce it to below 0.8V, which severely limits the device performance. In addition, there is a passivation process of precursor doping, such as doping long-chain alkyl containing sulfur into the perovskite precursor. However, this passivation method affects the crystalline quality and also leads to poor device performance. SUMMARY

[0005] To solve the above problems, the present disclosure provides a passivation method of a perovskite solar cell, comprising: passivating the perovskite solar cell by using a multi-component passivation system; wherein the multi-component passivation system comprises: a passivation agent containing a double amino group and iodine ions; a passivation agent containing a benzene ring and an amino group; and a passivation agent containing a piperazine ring and iodine ions.

[0006] In the passivation method of the present disclosure, the perovskite solar cell is passivated by using a multi-component passivation system, which comprises: first coating a passivation agent containing a double amino group and iodine ions on the perovskite layer of the perovskite solar cell; then coating a mixture of a passivation agent containing a benzene ring and an amino group and a passivation agent containing a piperazine ring and iodine ions on the perovskite solar cell with the passivation agent containing a double amino group and iodine ions; and performing gradient annealing on the perovskite solar cell.

[0007] In the passivation method of the present disclosure, the passivation agent containing bis-amino and iodine ions is selected from one or more of ethylenediamine dihydroiodide (EDAI), propylenediamine dihydroiodide (PDAI), ethylenediamine dihydrobromide (EDABr), and derivatives of ethylenediamine tetraacetic acid iodine (EDTA-I).

[0008] In the passivation method of the present disclosure, the passivation agent containing benzene ring and amino group is selected from one or more of phenethylammonium iodide (PEAI), naphthyl ethyl ammonium iodide (NEAI), p-methyl phenethylammonium iodide (Me-PEAI), and biphenyl ethyl ammonium iodide (BPEAI).

[0009] In the passivation method of the present disclosure, the passivation agent containing piperazine ring and iodine ions is selected from one or more of piperazine diiodide (PDI), hexamethylenetetramine diiodide (HMTDI), morpholine diiodide (MDI), and tetramethylpiperazine diiodide (TMPDI).

[0010] In the passivation method of the present disclosure, the molar ratio of the passivation agent containing bis-amino and iodine ions, the passivation agent containing benzene ring and amino group, and the passivation agent containing piperazine ring and iodine ions is 5:2:1.

[0011] In the passivation method of the present disclosure, the passivation agent is coated by roll coating, spin coating, blade coating, and dip coating, etc.

[0012] In the passivation method of the present disclosure, the gradient annealing includes at least two annealing processes successively performed from low temperature to high temperature.

[0013] In the passivation method of the present disclosure, the gradient annealing includes two annealing processes performed at 65-80℃ and 120-140℃.

[0014] The present disclosure also provides a perovskite solar cell comprising a passivation layer formed by the passivation method of the perovskite solar cell according to the above.

[0015] According to the passivation method of the perovskite solar cell of the present disclosure, on the one hand, the crystal defects are better passivated, the energy level matching is improved, the cell interface filling is better, so that the solar device has lower series resistance and higher open circuit voltage; on the other hand, by the gradient annealing method, the perovskite layer can maintain the crystal nucleus growth in the low-temperature annealing process and quickly volatilize the solvent in the high-temperature annealing process, so as to improve the crystalline quality and achieve the final purpose of improving the efficiency of the solar device. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 A schematic flow chart of a passivation method of a perovskite solar cell according to an embodiment of the present disclosure.

[0017] Figure 2 A schematic flow chart of a multi-component passivation system based passivation method according to one embodiment of the present disclosure.

[0018] Figure 3 A structural schematic of a perovskite solar cell according to one embodiment of the present disclosure.

[0019] Figure 4 A J-V curve of a perovskite solar cell according to one embodiment of the present disclosure. DETAILED DESCRIPTION

[0020] In order to make the skilled in the art better understand the technical solutions of the present disclosure, the technical solutions of the present disclosure are described in detail below in combination with the drawings.

[0021] In the following, example embodiments will be described more fully with reference to the accompanying drawings, in which example embodiments can, however, be implemented in different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to the skilled in the art.

[0022] The embodiments of the present disclosure and the features in the embodiments can be combined with each other without conflict if not limited.

[0023] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0024] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0025] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an overly literal or overly formal sense unless expressly so defined herein.

[0026] Unless otherwise specified, the term "concentration" used herein refers to mass concentration. The concentration of each substance in a mixed solution refers to the mass concentration of each substance based on the total amount of the mixed solution.

[0027] The present disclosure provides a multi-component passivation system for perovskite solar cells, the multi-component passivation system comprising:

[0028] a passivation agent containing a benzene ring and an amino group;

[0029] a passivation agent containing a benzene ring and an amino group;

[0030] a passivation agent containing a piperazine ring and iodine ions.

[0031] In the multi-component passivation system of the present disclosure, the passivation agent containing a benzene ring and an amino group is selected from one or more of phenethylammonium iodide (PEAI), naphthylethylammonium iodide (NEAI), p-methylphenethylammonium iodide (Me-PEAI), and biphenylethylammonium iodide (BPEAI).

[0032] In the multi-component passivation system of the present disclosure, the passivation agent containing a benzene ring and an amino group is selected from one or more of phenethylammonium iodide (PEAI), naphthylethylammonium iodide (NEAI), p-methylphenethylammonium iodide (Me-PEAI), and biphenylethylammonium iodide (BPEAI).

[0033] In the multi-component passivation system of the present disclosure, the passivation agent containing a piperazine ring and iodine ions is selected from one or more of piperazine diiodide (PDI), hexamethylenetetramine diiodide (HMTDI), morpholine diiodide (MDI), and tetramethylpiperazine diiodide (TMPDI).

[0034] In the multi-component passivation system of the present disclosure, the molar ratio of the passivation agent containing a benzene ring and an amino group, the passivation agent containing a piperazine ring and iodine ions, and the passivation agent containing a benzene ring and an amino group is 5:2:1.

[0035] In particular, the molar ratio of the passivation agent containing a benzene ring and an amino group and the passivation agent containing a piperazine ring and iodine ions is 1:1.6 to 1:4.

[0036] As shown in the present disclosure, a passivation method for a perovskite solar cell is also provided, comprising the following steps: Figure 1

[0037] S1- passivating the perovskite solar cell with a multi-component passivation system; wherein the multi-component passivation system comprises: a passivation agent containing a benzene ring and an amino group; a passivation agent containing a piperazine ring and iodine ions.

[0038] As shown in the present disclosure, a passivation method for a perovskite solar cell is also provided, comprising the following steps: Figure 2

[0039] S11- first coating the passivation agent containing a benzene ring and an amino group on the perovskite layer of the perovskite solar cell;​​

[0040] S12- Re-coating a mixture of the passivation agent containing benzene ring and amino group and the passivation agent containing piperazine ring and iodine ion on the perovskite solar cell with the passivation agent containing bis-amino group and iodine ion; and

[0041] S13- Gradient annealing the perovskite solar cell.

[0042] In the passivation method of the present disclosure, the passivation agent can be coated by slit coating, roll coating, spin coating, blade coating, and dip coating, etc. The common perovskite solar cell is divided into two types, large-size perovskite cell and small-size perovskite cell. The person skilled in the art can select the specific way of coating the passivation agent according to the need.

[0043] Generally, the large-size perovskite cell adopts the coating method (such as slit coating), the coating speed is 20-30 mm / s, which is suitable for low viscosity solution (such as low PEAI concentration or strong solvent volatility), and the injection speed is 0.1-0.5 mL / min. The injection speed = coating speed x film thickness x coating width, and the ratio of injection speed to coating speed is usually 100:1-150:1. If it is a high viscosity solution, the ratio of injection speed to coating speed is usually 160:1-180:1. The small-size perovskite cell adopts the spin coating method, and the rotation speed is 2400-3400 rpm.

[0044] The coating thickness of the passivation agent is 5-7 nm, and the large-size perovskite cell and the small-size perovskite cell can have the same coating thickness.

[0045] Generally, the passivation agent is dissolved in an organic solvent for coating, and the person skilled in the art can select the required organic solvent according to the specific type of the passivation agent. The organic solvent can be selected from one or more of ethanol, isopropanol, toluene or chlorobenzene. Preferably, in the multi-component passivation system of the present disclosure, the same solvent is used to dissolve each passivation agent.

[0046] The person skilled in the art can determine the concentration of the passivation agent in the passivation agent solution according to the specific type of the passivation agent. For example, the solution concentration of the passivation agent containing bis-amino group and iodine ion is 0.8-1.2 mg / mL, the solution concentration of the passivation agent containing benzene ring and amino group is 0.8-1.2 mg / mL, and the solution concentration of the passivation agent containing piperazine ring and iodine ion is 0.8-1.2 mg / mL. The concentration of the mixed solution of the passivation agent containing benzene ring and amino group and the passivation agent containing piperazine ring and iodine ion is 0.3-0.6 mg / mL.

[0047] In the passivation method of the present disclosure, the gradient annealing includes at least two annealing processes successively performed from low temperature to high temperature. The temperature range of the gradient annealing is 65-140℃, and the annealing time is 5-20min. For example, the gradient annealing includes 65-80℃ annealing and 120-140℃ annealing, and the two annealings are performed for 5-10min respectively.

[0048] In the passivation method of the present disclosure, the gradient annealing can also include three annealing processes performed at 65-80℃, 80-120℃ and 120-140℃ respectively, and the time of each annealing is 1-10min.

[0049] In the passivation method of the present disclosure, a passivation agent solution containing bis-amino and iodine ions is first coated, and passivation is performed relying on the coordination ability of bis-amino and the vacancy filling of iodine ions. Then, a mixed passivation agent solution containing a benzene ring and amino in the passivation agent and a passivation agent containing a piperazine ring and iodine ions is coated, and multi-angle passivation is achieved relying on the hydrophobic protection of the benzene ring and the grain boundary strengthening of the piperazine ring structure, so as to effectively reduce the interface potential barrier of the perovskite solar cell and improve the open circuit voltage.

[0050] The present disclosure also provides a perovskite solar cell, as shown in Figure 3 which comprises:

[0051] 1-glass substrate, 2-FTO layer, 3-NiOx layer, 4-self-assembled monolayer (SAM layer), 5-perovskite layer, 6-passivation layer, 7-electron transport layer and 8-top electrode, wherein the passivation layer is a layer formed by the above-mentioned multi-component passivation system of the present disclosure.

[0052] In order for those skilled in the art to more clearly understand the technical solutions of the present disclosure, the technical solutions of the present disclosure are described in detail below through specific examples.

[0053] Example 1

[0054] Under the conditions of ambient temperature 15-19℃ and humidity 10-15%, a perovskite solar cell glass substrate with a size of 50mm×50mm is selected, and the light transmittance of the glass substrate is higher than 83%.

[0055] A glass substrate coated with a 400nm-thick FTO layer is cleaned, and a 15nm-thick NiOx layer is formed on it by sputtering. Me-4PACz is selected as the SAM material, and IPA is selected as the solvent. The SAM material is uniformly dissolved to form a solution with a concentration of 0.8mg / ml; then the solution is spin-coated on the surface of the NiOx layer, and the spin-coating parameters are 3000rpm and spin-coating time is 30s.

[0056] A 1.5 mol / L perovskite precursor solution was prepared, containing 0.85 mol / L FAI, 0.15 mol / L CsI and 5% excess PbI2, using a mixture of DMF:DMSO = 4:1 as solvent, and the perovskite solution was coated on the SAM layer by spin coating. The operating parameters of spin coating were as follows: first step, 1000 rpm, acceleration 200 rpm / s, time 10 s; second step, 4000 rpm, acceleration 1000 rpm / s, time 32 s.

[0057] An isopropanol solution of EDAI was prepared with a concentration of 1.0 mg / mL, and was uniformly spin-coated on the perovskite layer. Then, isopropanol solutions of PEAI and PDI were prepared with concentrations of 0.8 mg / mL and 1.2 mg / mL, respectively, and the two solutions were mixed in a ratio of 2:1, and the mixed solution was spin-coated on the EDAI layer. The spin speed was 3000 rpm, and the time was 30 s.

[0058] The annealing platform was heated from 65°C to 80°C at a rate of 5°C / min, and then the glass substrate coated with the perovskite layer was placed in the annealing platform for annealing, and was kept at 80°C for 8 min; then the temperature was increased from 80°C to 120°C at a rate of 2°C / min, and was kept at 120°C for 5 min; then the temperature was increased from 120°C to 140°C at a rate of 5°C / min, and was kept at 140°C for 2 min.

[0059] After cooling, the sample was placed in a low-temperature evaporation chamber to evaporate C60 first. When the evaporation rate of C60 was stable at , C60 was evaporated onto the substrate to a thickness of 20 nm. Then, when the evaporation rate of the organic small-molecule hole-blocking layer BCP was stable at , BCP was evaporated onto the substrate to a thickness of 8 nm. Then the sample was moved to a high-temperature evaporation chamber to evaporate Cu. When the evaporation rate of the sample was stable at , Cu was evaporated onto the substrate to a thickness of 100 nm. After evaporation, the bus bar was attached for testing.

[0060] Example 2

[0061] The perovskite solar cell of Example 2 was prepared according to the preparation method of Example 1, except that the molar ratio of PEAI to PDI was 3:1.

[0062] Example 3

[0063] The perovskite solar cell of Example 3 was prepared according to the preparation method of Example 1, except that the molar ratio of PEAI to PDI was 4:1.

[0064] Comparative Example 1

[0065] A perovskite solar cell of Comparative Example 1 was prepared according to the preparation method of Example 1, except that only the isopropanol solution of EDAI was used for passivation.

[0066] Comparative Example 2

[0067] A perovskite solar cell of Comparative Example 2 was prepared according to the preparation method of Example 1, except that only the isopropanol solution of PDI was used for passivation.

[0068] Comparative Example 3

[0069] A perovskite solar cell of Comparative Example 3 was prepared according to the preparation method of Example 1, except that only the isopropanol solution of PEAI was used for passivation.

[0070] The solar cells prepared in each of the examples and comparative examples were tested for performance, and the data of the relevant performance is shown in Table 1.

[0071] Table 1 Comparison of performance of solar cells obtained in each of the examples and comparative examples

[0072] PCE Voc Jsc Isc FF Rs Rsh Example 1 19.70 7.55 3.61 0.06 0.74 17.37 986.44 Example 2 19.75 7.62 3.60 0.06 0.70 17.30 985.73 Example 3 19.68 7.65 3.64 0.06 0.72 17.32 986.25 Comparative Example 1 18.91 7.39 3.65 0.06 0.70 18.73 977.83 Comparative Example 2 18.97 7.35 3.53 0.06 0.73 17.63 965.45 Comparative Example 3 18.65 7.29 3.68 0.06 0.70 20.92 993.21

[0073] As can be seen from the data in Table 1, the perovskite solar cells prepared according to the multi-component passivation system and the passivation method comprising gradient annealing of the present disclosure have a significant improvement in the data of PCE and Voc, and at the same time ensure the stability of other performance parameters.

[0074] Example embodiments have been disclosed herein and, although the use of specific terms is expressly used herein, they are intended in the sense only of general descriptive purpose and not for purposes of limitation. In some embodiments, it will be apparent to those skilled in the art from this disclosure that the features, characteristics, and / or elements described in connection with a particular embodiment can be used, either alone or in combination with other embodiments, unless explicitly stated otherwise. Accordingly, it will be understood by those skilled in the art that various changes in form and details can be made without departing from the scope of the present disclosure as set forth in the appended claims.

Claims

1. A method for passivating a perovskite solar cell, comprising: passivating the perovskite solar cell with a multi-component passivation system; wherein the multi-component passivation system comprises: a passivation agent comprising a diamino group and iodine ions; a passivation agent comprising a benzene ring and an amino group; a passivation agent comprising a piperazine ring and iodine ions.

2. The passivation method of claim 1, wherein, passivating the perovskite solar cell with a multi-component passivation system, comprising: coating a passivation agent comprising a diamino group and iodine ions on a perovskite layer of the perovskite solar cell; coating a mixture of a passivation agent comprising a benzene ring and an amino group and a passivation agent comprising a piperazine ring and iodine ions on the perovskite solar cell with the passivation agent comprising a diamino group and iodine ions; and performing gradient annealing on the perovskite solar cell.

3. The passivation method according to claim 1 or 2, wherein, the passivation agent comprising a diamino group and iodine ions is selected from one or more of ethylenediamine dihydroiodide (EDAI), propylenediamine dihydroiodide (PDAI), ethylenediamine dihydrobromide (EDABr), and derivatives of ethylenediaminetetraacetic acid iodine (EDTA-I).

4. The passivation method according to claim 1 or 2, wherein, the passivation agent comprising a benzene ring and an amino group is selected from one or more of phenethylammonium iodide (PEAI), naphthylethylammonium iodide (NEAI), p-methylphenethylammonium iodide (Me-PEAI), and biphenylethylammonium iodide (BPEAI).

5. The passivation method according to claim 1 or 2, wherein, the passivation agent comprising a piperazine ring and iodine ions is selected from one or more of piperazinium diiodide (PDI), hexamethylenetetramine diiodide (HMTDI), morpholine diiodide (MDI), and tetramethylpiperazinium diiodide (TMPDI).

6. The passivation method according to claim 1 or 2, wherein, a molar ratio of the passivation agent comprising a diamino group and iodine ions, the passivation agent comprising a benzene ring and an amino group, and the passivation agent comprising a piperazine ring and iodine ions is 5:2:

1.

7. The passivation method according to claim 1 or 2, wherein, the passivation agent is coated by roll coating, spin coating, blade coating, dip coating, or the like.

8. The passivation method according to claim 2, wherein, the gradient annealing comprises at least two annealing processes performed in sequence from low temperature to high temperature.

9. The passivation method according to claim 2, wherein, the gradient annealing comprises two annealing processes performed at 65-80°C and 120-140°C.

10. A perovskite solar cell comprising a passivation layer formed by the method for passivating a perovskite solar cell according to any one of claims 1 to 9.

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