WO2024109424A1

WO2024109424A1 - Additive and use method therefor

Info

Publication number: WO2024109424A1
Application number: PCT/CN2023/126229
Authority: WO
Inventors: 李静; 常青; 尹君; 吴炳辉; 郑南峰
Original assignee: 嘉庚创新实验室
Priority date: 2022-11-22
Filing date: 2023-10-24
Publication date: 2024-05-30
Also published as: CN115843190A

Abstract

An additive, comprising a first component, wherein the first component comprises at least one of ferrocene and a ferrocene compound, and a polar solvent used for dissolving the ferrocene and the ferrocene compound. The provided additive can be used for surface modification of a metal electrode, surface passivation of a perovskite material and doping of a hole transport layer material, can inhibit ion migration, and can improve the photoelectric conversion efficiency and stability of a device; and the additive is particularly suitable for efficient doping of a hole transport layer material in perovskite solar cell of a normal structure.

Description

Additive and method of using the same

This application claims a Chinese patent application filed on November 22, 2022 with the State Intellectual Property Office of China, with application number: 202211464849.5, and the name of the invention is: "An additive and its method of use" as the basis, and claims its priority. The disclosed content of the Chinese patent application is hereby introduced as a whole into the text of this application.

Technical Field

The invention relates to an additive used in perovskite, in particular to a perovskite hole transport layer.

Background technique

In the field of perovskite photovoltaics, the photoelectric conversion efficiency (PCE) of perovskite solar cells (PSCs) based on organic-inorganic hybrid metal halide perovskites has increased from nearly 3.8% to about 25.7% in just over a decade, becoming one of the most promising new generation photovoltaic materials recognized worldwide. The hole transport layer is set between the perovskite light absorption layer and the metal electrode. It serves as a hole extraction functional layer and also a protective umbrella for the perovskite. It is one of the key factors that determine the photoelectric conversion efficiency and stability of perovskite solar cells.

At present, commonly used organic hole transport layer materials include 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD), polytriarylamine (PTAA), poly(3-hexylthiophene) (P3HT) and poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS), etc., and inorganic hole transport layer materials include CuSCN, NiO _x , MoS ₂ , MoO _x , etc. Although inorganic hole transport layer materials have good stability, the device efficiency is at a disadvantage. In the normal device structure, in order to obtain high photoelectric conversion efficiency, doped organic hole materials are often used as hole transport layers, but their own conductivity and mobility are very low, so they need to be additionally doped with dopants such as lithium trifluoromethanesulfonyl imide (Li-TFSI) to improve the electrical properties of the material. Although these dopants can improve the hole transport performance of organic materials, they often tend to aggregate and absorb water, or diffuse into other functional layers, thus affecting the overall stability of the device. Iodine vacancy defects are generated, which are not conducive to the stability of the perovskite structure. The large-scale generation of defects will lead to the failure of the perovskite active layer. They often migrate upward and cause the perovskite crystal to decompose. Over time, they slowly diffuse and can even migrate to the metal electrode and react with it, causing the overall device to be unstable. Therefore, it is crucial to select suitable additives in the hole transport layer to balance the performance and stability of the perovskite device. Often, the selection of additives can only act on a specific object of a functional layer, and cannot take into account the stability of the multifunctional layer.

In addition, the performance of the hole transport layer is also affected by ion migration in the perovskite structure. High-efficiency perovskite solar cells are mainly composed of perovskites containing mixed cations of cesium (Cs) and formamidine (FA) and a high proportion of iodide. The instability of iodine makes it easy for perovskites to produce related defects in the film. At the same time, these defects, including iodine vacancies and iodine interstitial defects, will cause interfacial charge recombination, resulting in a decrease in the efficiency and long-term operation stability of PSCs. And the further migration of iodine will affect the conductivity, Fermi level and structural stability of the hole transport layer. There are currently schemes to suppress the formation of iodine-related surface defects and ion migration by post-treating the perovskite surface with many compounds.

Summary of the invention

The main purpose of the present invention is to provide an additive that can inhibit ion migration in the hole transport layer and improve the problem of decreased device working stability caused by the generation of vacancy defects in the perovskite active layer. The technical solution adopted by the present invention to solve its technical problem is:

An additive, characterized in that it comprises a first component, wherein the first component comprises at least one of ferrocene and ferrocene compounds, and a polar solvent for dissolving the ferrocene and ferrocene compounds.

Preferably, the concentration of ferrocene and ferrocene-based compounds is 1-20 mg/mL.

Preferably, the ferrocene and ferrocene-based compounds include at least one of ferrocene hexafluorophosphate, ferrocene tetrafluoroborate, ferrocene trifluorosulfonate, ferrocene iodide and ferrocene.

Preferably, the polar solvent includes acetonitrile, DMF (N,N-dimethylformamide), DMSO (dimethylformamide), Sulfoxide), NMP (N-methylpyrrolidone) or at least one of the following.

The present invention also provides a surface modification method for a metal electrode, wherein the additive is coated on the metal electrode or between the metal electrode and an adjacent contact layer to modify the surface of the metal electrode.

The present invention also provides a method for passivating the surface of perovskite, which adopts the additive to be coated on the surface of organic halide perovskite or inorganic halide perovskite to passivate the surface of the perovskite.

The present invention also provides a perovskite photoelectric device, wherein the perovskite light absorbing layer is modified by the additive, and/or the metal electrode is modified by the additive.

Preferably, the additive provided by the present invention further comprises a second component, wherein the second component comprises an aprotic non-polar solvent.

Preferably, the volume ratio of the first component to the second component is (1-10):100.

Preferably, the aprotic non-polar solvent comprises at least one of diethyl ether, ethyl acetate, chlorobenzene, toluene or chloroform.

The present invention also provides a hole transport layer, which is prepared by using the additive.

The present invention also provides a method for preparing a hole transport layer, which is prepared by adding hole transport layer materials into the additives to react to obtain a mixed solution, and coating the mixed solution on a substrate.

Preferably, the mass ratio of the ferrocene and ferrocene-based compounds to the hole transport layer material is 1:10-1:90.

Preferably, the hole transport layer material includes at least one of Spiro-OMeTAD, PTAA, P3HT, phthalocyanine, and NiO _x .

The present invention also provides another perovskite photoelectric device, comprising the hole transport layer or the hole transport layer prepared by the preparation method.

Compared with the background technology, the technical solution of the present invention has the following advantages:

1. The additive provided by the present invention can improve the oxidation potential of the metal electrode on the upper layer of the hole transport layer, inhibit ion migration in the hole transport layer, and improve the problem of decreased device working stability caused by the generation of vacancy defects in the perovskite active layer. Therefore, after being used in the hole transport layer material, it can inhibit ion migration and improve the photoelectric conversion efficiency and stability of the overall device, and is particularly suitable for the doping of high-efficiency hole transport layer materials of ortho-perovskite solar cells; for perovskite surface modification, it can effectively inhibit ion migration in perovskite films; for metal electrode surface modification, it can enhance antioxidant capacity and stability, and improve the flatness of the metal electrode surface.

2. The ferrocene and ferrocene compounds of the present invention are not polymers, nor are they used as terminal groups, and can exert an oxidizing effect on hole transport layer materials. At the same time, the additives of the present invention can be used not only in the hole transport layer, but also can be used alone on the surface modification of perovskite or on metal electrodes.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

FIG. 1 shows different usages of additives in Examples 1-11 (implementation route 3), Example 12 (implementation route 1), and Examples 13-14 (implementation route 2).

FIG2 is an X-ray photoelectron spectrum of the gold electrode layer of the perovskite solar cell prepared by Example 1 and Comparative Example 1 after aging. Wherein: FIG2a and FIG2b are X-ray photoelectron spectrum of gold (Au) and iodine (I) measured in Example 1, and FIG2c and FIG2d are X-ray photoelectron spectrum of gold (Au) and iodine (I) measured in Comparative Example 1, respectively.

FIG3 is an X-ray photoelectron spectrum of the hole transport layer of the perovskite solar cell prepared by Example 1 and Comparative Example 1 after aging. Wherein: FIG3a and FIG3b are X-ray photoelectron spectra of lead (Pb) and iodine (I) measured in Example 1, and FIG3c and FIG3d are X-ray photoelectron spectra of lead (Pb) and iodine (I) measured in Comparative Example 1. Photoelectron spectrum.

FIG. 4 is a graph showing the light stability test results of the perovskite solar cells prepared using Example 1 and Comparative Example 1.

FIG5 is a graph showing the photoelectric conversion efficiency test results of the perovskite solar cells prepared using Example 1 and Comparative Example 1.

FIG6 is a graph showing the ratio of iodine/lead content on the surface of the perovskite films prepared in Example 12 and Comparative Example 2 measured based on X-ray photoelectron spectroscopy.

FIG. 7 is a graph showing the light stability test results of the perovskite films prepared using Example 12 and Comparative Example 2.

FIG8 is a graph showing the test results of the oxidation potential of the gold electrode layer obtained after annealing the metal-deposited perovskite film prepared in Example 13 and Comparative Example 3.

FIG9 is a scanning electron microscope image of the upper metal layer of the metal-deposited perovskite film prepared by Example 13 and Comparative Example 3.

Detailed ways

Example 1

In this embodiment, the preparation of a normal structure perovskite solar cell includes the following steps:

(1) Substrate cleaning: Place the etched FTO (F-doped Tin Oxide) transparent conductive glass on a cleaning rack and ultrasonically clean it four times with aqueous solution, acetone, ethanol, and ethanol in sequence. Each cleaning time is 15 min. After cleaning, take out the glass and blow dry it with nitrogen. Place the glass in a UV ozone cleaning machine and clean the glass surface for 15 min.

(2) Preparation of tin oxide electron transport layer (also known as n-type semiconductor): The tin oxide nanoparticle aqueous solution was diluted with ultrapure water at a volume ratio of 1:2, and the target solution was obtained after ultrasonication for 30 seconds. The solution was then heated at 3000 rpm/s. The electron transport layer was obtained by spin coating on the cleaned FTO substrate at a rotation speed of 1000 nm and annealing at 120°C for 40 min.

(3) Preparation of perovskite light absorbing layer: Lead iodide, iodoformamide, methylamine bromide and lead bromide were dissolved in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide, and shaken for 2 h to obtain a perovskite precursor solution. The precursor solution was then spin-coated on the electron transport layer and annealed at 100°C for 60 min to obtain a perovskite light absorbing layer.

Among them, the ratio of lead iodide, iodomethane, methylammonium bromide, lead bromide, N,N-dimethylformamide, and dimethyl sulfoxide is 353 mg:120 mg:4 mg:13 mg:400 μL:100 μL.

(4) Preparation of hole transport layer.

(5) Metal electrode layer deposition: vacuum thermal evaporation deposition 80nm of metal was evaporated at a rate of 1.5 times that of the original material to obtain a complete upright structure perovskite solar cell.

The method for using the additives is shown in the implementation route 3 in FIG1 . The preparation of the hole transport layer specifically includes the following steps:

S1: Weigh 1 mg of ferrocene hexafluorophosphate (FcPF ₆ ) and dissolve it in 1 mL of chlorobenzene solution;

S2: The hole transport layer material Spiro-OMeTAD was dissolved in chlorobenzene in S1 at 90 mg/mL, shaken well, dissolved by ultrasonication and filtered;

S3: Add 39 μL of tert-butylpyridine (tBP) to the clear solution obtained in 1 mL of S2 and shake well;

S4: Dissolve lithium bis(trifluoromethane)sulfonyl imide (Li-TFSI) at 520 mg/mL in acetonitrile solution, take 23 μL and add it to the solution obtained in S3 and shake well;

S5: Add the prepared solution dropwise onto the perovskite light absorbing layer at a speed of 4000 rpm/s for 30 seconds.

Comparative Example 1

In this comparative example, a normal structure perovskite solar cell was prepared using the same preparation method as in Example 1. The method is different in that the hole transport layer is prepared in step (4), and the preparation of the hole transport layer specifically includes the following steps:

S1: The hole transport layer material Spiro-OMeTAD was dissolved in chlorobenzene at 90 mg/mL, shaken well, dissolved by ultrasonication and filtered;

S2: Add 39 μL of tert-butylpyridine (tBP) to 1 mL of the clear solution obtained in S1 and shake well;

S3: Dissolve lithium bis(trifluoromethane)sulfonyl imide (Li-TFSI) at 520 mg/mL in acetonitrile solution, take 23 μL and add it to the solution obtained in S2 and shake well;

S4: Add the prepared solution dropwise onto the perovskite light absorbing layer at a speed of 4000 rpm/s for 30 seconds.

Example 2

In this embodiment, a normal structure perovskite solar cell is prepared by the same preparation method as in Example 1, except that the hole transport layer is prepared in step (4), wherein the method for using the additive is shown in the implementation route 3 in FIG1 . The preparation of the hole transport layer specifically includes the following steps:

S1: Weigh 1 mg of iodoferrocene and dissolve it in 1 mL of chlorobenzene solution;

S4: Dissolve Li-TFSI at 520 mg/mL in acetonitrile solution, take 23 μL and add it to the solution obtained in S3 and shake well;

Example 3

S1: Weigh 1 mg of ferrocene hexafluorophosphate and dissolve it in 1 mL of chlorobenzene solution;

S5: Add the prepared solution dropwise onto the perovskite light absorbing layer at a speed of 3500 rpm/s for 30 seconds.

Example 4

In this embodiment, a normal structure perovskite solar cell is prepared by the same preparation method as in Example 1, except that the hole transport layer is prepared in step (4), and the method for using the additive is shown in the implementation route 3 in FIG1 . The preparation of the hole transport layer specifically includes the following steps:

S1: Weigh 1 mg of ferrocene tetrafluoroborate (FcBF ₄ ) and dissolve it in 1 mL of chlorobenzene solution;

S2: The hole transport layer material Spiro-OMeTAD was dissolved in S1 chlorobenzene at 90 mg/mL and shaken to obtain a purple-red clear solution;

S5: Add the prepared solution dropwise onto the perovskite light absorbing layer at a speed of 3500 rpm/s for 25 seconds.

Example 5

S1: Weigh 1 mg of ferrocene and dissolve it in 1 mL of chlorobenzene solution;

S2: The hole transport layer material Spiro-OMeTAD was dissolved in chlorobenzene in S1 at 73 mg/mL, shaken well, dissolved by ultrasonication and filtered;

S3: Add 29 μL of tert-butylpyridine (tBP) to the clear solution obtained in 1 mL of S2 and shake well;

S4: Dissolve Li-TFSI at 520 mg/mL in acetonitrile solution, take 18 μL and add it to the solution obtained in S3 and shake well;

Example 6

S4: Dissolve Li-TFSI at 520 mg/mL in acetonitrile solution, take 18 μL and add it to the solution obtained in S2 and shake well;

S5: Add the prepared solution dropwise onto the perovskite light absorbing layer at a speed of 4000 rpm/s for 25 seconds.

Example 7

S1: Weigh 20 mg of ferrocene hexafluorophosphate (FcPF ₆ ) and dissolve it in 1 mL of acetonitrile solution and shake well;

S2: Dissolve the hole transport layer material PTAA in chlorobenzene at 10 mg/mL and shake well;

S3: Take 40 μL of S1 and add it to the solution obtained in S2 and shake well;

S4: Add the prepared solution dropwise onto the perovskite light absorbing layer at a speed of 3500 rpm/s for 30 seconds.

Example 8

S1: Weigh 20 mg of ferrocene hexafluorophosphate (FcPF ₆ ) and dissolve it in 1 mL of N,N-dimethylformamide solution and shake well;

S3: Take 40 μL of S1 and add it to the solution obtained in S2 and shake well;

Example 9

S2: Dissolve the hole transport layer material P3HT in chloroform at 12 mg/mL and shake well;

S3: Take 40 μL of S1 and add it to the solution obtained in S2 and shake well;

Example 10

S2: Dissolve the hole transport layer material phthalocyanine in chloroform at 10 mg/mL and shake well;

S3: Take 40 μL of S1 and add it to the solution obtained in S2 and shake well;

Embodiment 11

S2: Dissolve the hole transport layer material NiO _x in chloroform at 10 mg/mL and shake well;

S3: Take 40 μL of S1 and add it to the solution obtained in S2 and shake well;

Example 12

In this embodiment, the perovskite film is prepared, including the following steps:

(2) Preparation of perovskite light absorbing layer: Lead iodide, iodoformamide, methylamine bromide and lead bromide were dissolved in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide, and shaken for 2 h to obtain a perovskite precursor solution. The precursor solution was then spin-coated on the electron transport layer and annealed at 100°C for 60 min to obtain a perovskite light absorbing layer.

The method of using the additives is shown in the implementation route 1 in FIG. 1 . After the perovskite light absorbing layer is prepared, The steps include:

S1: Weigh 20 mg of ferrocene hexafluorophosphate (FcPF ₆ ) and dissolve it in 1 mL of acetonitrile solution, shake well, and filter;

S2: Take 20 μL of S1 and spin-coat it on the surface of the perovskite light-absorbing layer in the perovskite photoelectric device at a dynamic speed of 3500 rpm/s;

S3: Low temperature annealing at 800°C for 5 minutes.

Comparative Example 2

In this comparative example, the perovskite film is prepared by the same preparation method as in Example 12, except that after the perovskite light absorbing layer is prepared, the following steps are included:

S1: Take 20 μL of acetonitrile solution and spin coat it on the surface of the perovskite light absorbing layer in the perovskite photoelectric device at a dynamic speed of 3500 rpm/s;

S2: Low temperature annealing at 800°C for 5 min.

Example 13

In this embodiment, the perovskite film deposited with metal is prepared, including the following steps, wherein the method of using the additive is as shown in the implementation route 2 in FIG. 1 :

(2) Preparation of perovskite light-absorbing layer: Dissolve lead iodide, iodoformamidine, methylamine bromide, and lead bromide in N,N-dichloromethane. The perovskite precursor solution was obtained by shaking in a mixed solvent of methylformamide and dimethyl sulfoxide for 2 h, and then the precursor solution was spin-coated on the electron transport layer and annealed at 100°C for 60 min to obtain the perovskite light absorbing layer.

(3) Use of additives:

S3: low temperature annealing at 800°C for 5 min;

S4: The modified optoelectronic device film is subjected to metal deposition to deposit 80 nm of gold on the perovskite surface.

Comparative Example 3

In this embodiment, the preparation of a metal-deposited perovskite film includes the following steps:

(3) Metal deposition:

S2: low temperature annealing at 800°C for 5 min;

S3: Perform metal deposition on the optoelectronic device film to deposit 80 nm of gold (Au) on the surface of the perovskite.

Embodiment 14

In this embodiment, a perovskite film with metal deposited thereon is prepared by the same preparation method as in Example 13, except that an additive is used in step (3), specifically comprising the following steps:

S3: low temperature annealing at 800°C for 5 min;

S4: The modified optoelectronic device film is subjected to metal deposition to deposit 80 nm of silver (Ag) on the surface of the perovskite.

Performance Testing

1. Perovskite solar cells

(1) X-ray photoelectron spectroscopy test of metal electrode layer

The perovskite solar cells prepared using Example 1 and Comparative Example 1 were photoaged in a nitrogen environment at 85°C for 7 days, and the X-ray photoelectron spectrum of the gold electrode layer was tested. The measured results are shown in Figure 2. The X-ray photoelectron spectrum of gold (Au) and iodine (I) measured in Example 1 and the X-ray photoelectron spectrum of gold (Au) and iodine (I) measured in Comparative Example 1 correspond to Figures 2a, 2b and 2c, 2d, respectively. It can be seen from Figure 2 that, relative to Example 1, the binding energy of the gold electrode layer of the perovskite solar cell prepared using Comparative Example 1 shifts to a higher energy, and corresponds to the standard AuI peak position (88.1 eV), and an obvious I signal is also detected. However, the gold electrode layer of the perovskite solar cell prepared using Example 1 has no Au shift and is consistent with the standard peak position, and no I signal is detected. The signal of I is shown, indicating that the perovskite solar cell prepared with additives can inhibit the migration of I ions, thereby reducing the impact on the metal electrode.

(2) X-ray photoelectron spectroscopy test of hole transport layer

The perovskite solar cells prepared in Example 1 and Comparative Example 1 were light aged for 7 days in a nitrogen environment at 85°C, and the X-ray photoelectron spectrum of the hole transport layer was tested. The measured results are shown in Figure 3. The X-ray photoelectron spectrum of lead (Pb) and iodine (I) measured in Example 1 and the X-ray photoelectron spectrum of lead (Pb) and iodine (I) measured in Comparative Example 1 correspond to Figures 3a, 3b and 3c, 3d, respectively. It can be seen from Figure 3 that, compared with the hole transport layer of the perovskite solar cell prepared in Comparative Example 1, an obvious Pb/I signal can be detected, while no Pb/I signal is detected in the hole transport layer of the perovskite solar cell prepared in Example 1, indicating that the use of the additives inhibits the longitudinal migration of Pb/I in the ions in the perovskite layer during the aging process, thereby inhibiting the migration of ions in the hole transport layer.

(3) Light stability test

The perovskite solar cells prepared in Example 1 and Comparative Example 1 were subjected to a light stability test (room temperature, AM1.5G sunlight irradiation), and the measured results are shown in Figure 4. As can be seen from Figure 4, the photoelectric conversion efficiency of the perovskite solar cell prepared in Comparative Example 1 decays rapidly within 200 hours, while the photoelectric conversion efficiency of the perovskite solar cell prepared in Example 1 can be maintained at more than 95% within 600 hours without decay. In comparison, the perovskite solar cell prepared using the additive has a higher photoelectric conversion efficiency and can maintain better operating stability under light.

(4) Photovoltaic testing of perovskite cells

The perovskite solar cells prepared in Examples 1-4 and Comparative Example 1 were subjected to photoelectric tests, and the test results are shown in Table 1. As can be seen from Table 1, the perovskite solar cells prepared in Examples 1-4 have good open circuit voltage, short circuit voltage, and In terms of the four core performance indicators of flux density, filling factor, and efficiency, they are all better than the perovskite solar cell prepared in Comparative Example 1, indicating that the perovskite solar cell prepared using additives has better photoelectric performance.

The photoelectric conversion efficiency of the perovskite solar cells prepared in Example 1 and Comparative Example 1 was repeatedly tested, and the statistical distribution diagram of the test results is shown in Figure 5. As can be seen from Figure 5, the perovskite solar cell prepared in Example 1 has higher photoelectric conversion efficiency, better device performance, and better efficiency stability.

Table 1 Photoelectric test results of perovskite solar cells prepared by Examples 1-4 and Comparative Example 1

2. Perovskite thin film

(1) Ion migration test

After the perovskite films prepared in Example 12 and Comparative Example 2 were light aged for 7 days in a nitrogen environment at 85°C, the X-ray photoelectron spectroscopy of lead (Pb) and iodine (I) was tested, and the X-ray photoelectron spectra of lead and iodine were integrated. The obtained iodine/lead ratio results are shown in Figure 6. As can be seen from Figure 6, the iodine/lead ratio of the perovskite film prepared in Example 12 after aging is closer to 3 (perovskite has an ABX ₃ structure, and the iodine/lead ratio is close to 3, which indicates that the ion migration is low), indicating that the ion migration of the perovskite film prepared using the additive is The migration of ions can be slowed down and ion migration can be more effectively suppressed.

(2) Light stability test

After the perovskite films prepared in Example 12 and Comparative Example 2 were light aged for 7 days in a nitrogen environment at 85°C, the crystallization peak intensity and decomposition were compared by X-ray diffraction test, and the test results are shown in Figure 7. As can be seen from Figure 7, after the perovskite film prepared in Comparative Example 2 was light aged, the diffraction peak intensity of the perovskite film decreased, and a stronger crystallization peak of lead iodide appeared at 13°, while the diffraction peak intensity of the perovskite film prepared in Example 12 after light aging was similar to that of the perovskite film prepared in Comparative Example 2 without light aging, indicating that the perovskite film prepared using the additive has better stability.

3. Deposition of metal-deposited perovskite films

(1) Metal electrode oxidation potential test

The metal-deposited perovskite film prepared in Example 13 and Comparative Example 3 was subjected to thermal annealing treatment to remove the perovskite light-absorbing layer on the film, and the gold electrode layer to be tested was obtained, and then the redox potential was tested by a three-electrode system cyclic voltammetry (the electrolyte was a 0.4 mol/L Na ₂ SO ₄ aqueous solution, the reference electrode was an Ag/AgCl electrode immersed in a saturated potassium chloride solution, the counter electrode was a Pt electrode, and the metal electrode layer was fixed with an electrode clamp as a working electrode, and the cyclic voltammetry test method was used, the scanning speed was 5 mV/s, and a stable spectrum was obtained after multiple scans), and the test results are shown in Figure 8. The oxidation potential test diagrams of the gold electrode layer to be tested obtained in Comparative Example 3 and the gold electrode layer to be tested obtained in Example 13 are shown in Figures 8a and 8b, respectively. As can be seen from Figure 8, compared with the gold electrode layer to be tested obtained in Comparative Example 3, the gold electrode layer to be tested (modified with additives) obtained in Example 13 has a higher oxidation potential (1.34 V) and enhanced antioxidant capacity.

(2) Stability test

The metal-deposited perovskite films prepared in Example 13 and Comparative Example 3 were aged for 3 days under indoor ambient light, and the surface morphology of the perovskite films was observed by scanning electron microscopy, and the corrosion of the gold electrode was detected by direct comparison. The scanning electron microscope image obtained by the test is shown in Figure 9, and the surface morphologies of Comparative Example 3 treated with light, Comparative Example 3 treated with light, and Example 13 treated with light are shown in Figures 9a, 9b, and 9c, respectively. It can be seen from Figure 9 that the Au film on the upper surface of the perovskite film prepared in Comparative Example 3 has been morphologically damaged and corroded before light aging, and the corrosion situation has seriously deteriorated after light aging, while the Au film on the upper surface of the perovskite film prepared in Example 13 remains original dense and flat after light aging, and has higher stability.

The above description is only a preferred embodiment of the present invention, and therefore cannot be used to limit the scope of the present invention. That is, equivalent changes and modifications made according to the patent scope of the present invention and the contents of the specification should still fall within the scope of the present invention.

Industrial Applicability

The present invention discloses an additive, comprising a first component, wherein the first component comprises at least one of ferrocene and ferrocene compounds, and a polar solvent for dissolving the ferrocene and ferrocene compounds. The additive provided by the present invention can be used for surface modification of metal electrodes, surface passivation of perovskite materials, and hole transport layer materials, can inhibit ion migration, and can improve the photoelectric conversion efficiency and stability of the overall device, and is particularly suitable for doping of high-efficiency hole transport layer materials of ortho-structure perovskite solar cells, and has industrial practicability.

Claims

An additive, characterized in that it comprises a first component, wherein the first component comprises at least one of ferrocene and ferrocene compounds, and a polar solvent for dissolving the ferrocene and ferrocene compounds.
The additive according to claim 1, characterized in that the concentration of ferrocene and ferrocene-based compounds is 1-20 mg/mL.
An additive according to claim 1 or 2, characterized in that the ferrocene and ferrocene compounds include at least one of ferrocene hexafluorophosphate, ferrocene tetrafluoroborate, ferrocene trifluorosulfonate, ferrocene iodide and ferrocene.
An additive according to any one of claims 1 to 3, characterized in that the polar solvent comprises at least one of acetonitrile, N,N-dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone.
A method for surface modification of a metal electrode, characterized in that the additive described in any one of claims 1 to 4 is coated on the metal electrode or between the metal electrode and an adjacent contact layer to modify the surface of the metal electrode.
A method for passivating the surface of perovskite, characterized in that: the additive described in any one of claims 1 to 4 is coated on the surface of an organic halide perovskite or an inorganic halide perovskite to passivate the surface of the perovskite.
A perovskite photoelectric device, characterized in that: the perovskite light absorbing layer is modified by the additive according to any one of claims 1 to 4, and/or the metal electrode is modified by the additive according to any one of claims 1 to 4.
An additive according to any one of claims 1 to 4, characterized in that the additive further comprises a second component, and the second component comprises an aprotic non-polar solvent.
An additive according to claim 8, characterized in that the volume ratio of the first component to the second component is (1-10):100.
An additive according to claim 8, characterized in that the aprotic non-polar solvent comprises at least one of ether, ethyl acetate, chlorobenzene, toluene or chloroform.
A hole transport layer, characterized in that the hole transport layer is prepared using the additive according to any one of claims 8 to 10.
A method for preparing a hole transport layer, characterized in that the hole transport layer material is added to the additive according to any one of claims 8 to 10 to react to obtain a mixed solution, and the mixed solution is coated on a substrate to prepare the hole transport layer.
The preparation method according to claim 12, characterized in that the mass ratio of the ferrocene and ferrocene-based compounds to the hole transport layer material is 1:10-1:90.
The preparation method according to claim 12 is characterized in that the hole transport layer material includes at least one of Spiro-OMeTAD, PTAA, P3HT, phthalocyanine, and NiO x .
A perovskite photoelectric device, characterized in that it comprises the hole transport layer according to claim 11 or a hole transport layer prepared by the preparation method according to any one of claims 12 to 14.