C60-corannulene composite thin film and preparation method of perovskite solar cell of C60-corannulene composite thin film

Abstract

The invention provides a preparation method of a C60-corannulene composite film and a perovskite solar cell thereof. By adjusting the ratio of C60 to corannulene, the morphology and photoelectric properties of the film can be regulated and controlled. When the ratio of the two is appropriate, the highest photoelectric conversion efficiency of the perovskite solar cell using the composite film as an electron transport layer can reach 21.69%, and the perovskite solar cell has good service reliability, which plays an enlightenment role in improving the electron transport efficiency of the perovskite solar cell and promoting the preparation of the efficient perovskite solar cell by an all-solution method.

Description

Technical Field

[0001] The present invention relates to the field of solar cells, and in particular to a C 60 - Preparation method of corannulene composite film and perovskite solar cell thereof. Background Art

[0002] Compared to traditional silicon-based photovoltaic technology, perovskite solar cells offer advantages such as lower cost, solution preparation, and lightweight construction, demonstrating promising industrial prospects. Perovskite solar cells primarily consist of a transparent conductive substrate, an electron / hole transport layer, a perovskite layer, and a counter electrode. Cell structures can be categorized as either regular or trans-structured. Compared to regular structures, trans-structured cells offer reduced forward and reverse scanning hysteresis, improved stability, lower production costs, and the advantage of being amenable to assembly into stacked cells with traditional solar cells such as silicon and copper indium gallium tin. Consequently, these cells have garnered increasing attention from both scientific research and industry in recent years.

[0003] In inverse perovskite solar cells, bare cage fullerene C 60 It is the best performing and most commonly used electron transport layer material. 60 The strong π-π interaction between carbon cages causes the carbon cages to tend to aggregate and crystallize, resulting in poor solubility and film-forming properties of the material. As a result, it is impossible to obtain an electron transport layer film with stable morphology, dense uniformity and excellent performance through current liquid phase preparation methods (such as spin coating, blade coating, etc.). Therefore, in today's mainstream high-performance inverse structure perovskite solar cells, C 60 Electron transport layer thin films can only be prepared using vacuum thermal evaporation. Compared with the liquid phase film forming method, which is low cost, easy to operate, and can be prepared on a continuous and large scale, the vacuum thermal evaporation method has the disadvantages of high raw material and equipment costs, high energy consumption, and cumbersome operation. In addition, this process is difficult to achieve continuous and large-scale thin film preparation. Therefore, it is necessary to develop a low-cost, high-performance C 60 The liquid phase preparation method of electron transport layer thin film is an important technical challenge faced in realizing the all-solution method for preparing high-efficiency perovskite solar cells. Summary of the Invention

[0004] In view of the problems existing in the prior art, the present invention provides a C 60 - preparation method of corannulene composite film and its perovskite solar cell. 60 Solution, improve C 60 The agglomeration and crystallization of the material increases the C 60 The solubility and film-forming properties of the material enable C 60Liquid-phase film formation of the electron transport layer. At the same time, the unique bowl-shaped structure of corannulene and the spherical structure of fullerene are highly compatible, and there is a strong chemical interaction between the two. The formation of a chemical assembly can enhance the electron transport performance within the film, thereby improving the photoelectric conversion efficiency of the battery.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions: A C 60 -The preparation method of corannulene composite film specifically comprises the following steps: (1) Weigh C according to a certain mass ratio 60 and corannulene powder, adding an appropriate amount of mixed solvent; (2) Place the solution at a certain temperature and stir for a certain period of time until the powder is completely dissolved to obtain a clear solution. Wait until the solution temperature drops to room temperature and then set aside; (3) Using liquid phase preparation method to obtain C 60 -corannulene composite film, and annealing the film at a certain temperature for a certain time until the solvent is completely evaporated.

[0006] Preferably, in step (1), the mass ratio C 60 : corannulene = 1: (0.01~0.5), preferably, C 60 : corannulene = 1: 0.02; the compound C 60 It is a completely closed all-carbon cage molecule composed of 60 carbon atoms, corannulene (C 20 H 10 ) is a surface-shaped molecule with a central five-membered ring structure, which can be regarded as C 60 A fragment of a molecule with the following chemical structure: Preferably, the mixed solvent comprises solvent A (carbon disulfide, dichloromethane, chloroform, benzene, toluene, chlorobenzene, o-dichlorobenzene, m-trimethylbenzene, etc.) and solvent B (N,N'-dimethylformamide, dimethyl sulfoxide, methanol, ethanol, trifluoroethanol, isopropanol, deionized water, etc.), and the volume ratio of the mixed solvent is solvent A: solvent B = 1: (0.001~0.1).

[0007] Preferably, in step (2), the stirring temperature is 20-80° C., the stirring time is 0.5-4 hours, and the stirring is carried out under nitrogen protection.

[0008] Preferably, in step (3), the liquid phase preparation method includes spin coating, blade coating, spray coating or slit coating, the annealing temperature is 60-120° C., and the annealing time is 5-60 minutes.

[0009] A perovskite solar cell comprises a transparent conductive substrate, a hole transport layer, a perovskite layer, an electron transport layer, a buffer layer and a counter electrode layer stacked in sequence, wherein the electron transport layer is the above-mentioned C 60 -corannulene composite film.

[0010] Preferably, the transparent conductive substrate is an indium tin oxide (ITO) / glass substrate, a fluorine-doped tin oxide (FTO) / glass substrate, an ITO / polyethylene naphthalate (PEN) substrate, or an ITO / polyethylene terephthalate (PET) substrate.

[0011] Preferably, the hole transport layer is nickel oxide (NiO x ), polytriphenylamine (PTAA), PEDOT:PSS, (2-(9H-carbazol-9-yl)ethyl)phosphonic acid (2PACz).

[0012] Preferably, the perovskite layer is MAPbI3, FAPbI3, CsPbI3, Cs x (FA y MA 1-y ) 1-x Pb(I z Br 1-z )3.

[0013] Preferably, the buffer layer is bathocuproine (BCP), lithium fluoride (LiF), fullerene derivatives (bis-C 60 ).

[0014] Preferably, the counter electrode layer is Ag, Au, Cu, or C.

[0015] The present invention provides a C 60 -corannulene composite film and its preparation method of perovskite solar cell. 60 The ratio of corannulene to olefins can be used to control the film's morphology and optoelectronic properties. When the ratio of the two is appropriate, perovskite solar cells using this composite film as an electron transport layer can achieve a maximum photoelectric conversion efficiency of 21.69% and exhibit excellent service reliability. This has implications for improving the electron transport efficiency of perovskite solar cells and promoting the all-solution method for preparing high-efficiency perovskite solar cells.

[0016] After adopting the above technical solution, the present invention has the following beneficial effects compared with the background technology: 1. The present invention provides a C 60 -The preparation method of corannulene composite film, for the first time prepared a C for perovskite solar cells 60 - corannulene electron transport layer, achieving high efficiency C 60 Liquid phase film formation of electron transport layer.

[0017] 2. C provided by the present invention 60 -Cranium ene composite films have good film morphology and stability, and can be used to improve the service reliability of perovskite solar cells.

[0018] 3. C provided by the present invention 60 Spherical C-colanthene in composite films 60 The molecules can react chemically with the bowl-shaped corannulene molecules, and there is charge transfer within the formed chemical assembly, which can be used to improve the photoelectric conversion efficiency of perovskite solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 In Example 1 of the present invention, different C 60 and corannulene mass ratio of the prepared perovskite solar cell device JV curve chart.

[0020] Figure 2 This is Example 1 (C 60 : corannulene = 1:0.02) and the perovskite solar cell device prepared in Comparative Example 1 JV curve chart.

[0021] Figure 3 These are atomic force microscope morphology images of the films prepared in Example 1 of the present invention and Comparative Example 1.

[0022] Figure 4 In Example 1 of the present invention, different C 60 Surface current diagram of the film prepared with different mass ratios of 1% and 2% of corannulene.

[0023] Figure 5 C in the present invention 60 Liquid phase H-NMR spectrum of chemical reaction with corannulene.

[0024] Figure 6 C in the present invention 60 Fluorescence spectrum of charge transfer with corannulene. DETAILED DESCRIPTION

[0025] In order to further illustrate the purpose, technical solutions and advantages of the present invention, the present invention is further described in detail below through specific implementation methods in combination with the accompanying drawings and examples. In some cases, some operations related to the present application are not shown or described in the specification. This is to avoid the core part of the present application being overwhelmed by excessive description. For those skilled in the art, it is not necessary to describe these related operations in detail. They can fully understand the related operations based on the description in the specification and the general technical knowledge in the field.

[0026] Unless otherwise specified, the experimental methods described in the following examples are conventional methods; the materials and reagents used are all commercially available unless otherwise specified.

[0027] In addition, the features, operations, or characteristics described in the specification may be combined in any appropriate manner to form various embodiments. Furthermore, the steps or actions in the method description may be reordered or adjusted in a manner readily apparent to those skilled in the art. Therefore, the various sequences in the specification and drawings are provided solely for the purpose of clearly describing a particular embodiment and are not intended to be mandatory, unless otherwise specified.

[0028] Example 1 Preparation C 60 The steps of corannulene composite film are as follows: (1) C 60 The powders of o-dichlorobenzene and corannulene were weighed in different mass ratios, and mixed solvent was added in a volume ratio of o-dichlorobenzene: deionized water = 1:0.02. 60 The total concentration of hydroxybenzoate and corannulene was 20 mg / mL.

[0029] (2) Place the solution under nitrogen and heat at 50°C with stirring for 2 hours until the powder is completely dissolved to obtain a clear solution. Wait until the solution temperature drops to room temperature and set aside.

[0030] (3) Prepared by spin coating at a speed of 3000 rpm for 30 seconds, and then annealed at 100 ° C for 15 minutes in nitrogen to obtain C 60 -Cornulene composite film (CC film).

[0031] Example 2 C prepared in Example 1 60 -corannulene composite film prepared perovskite solar cells and their photovoltaic performance characterization, this photovoltaic device is named CC.

[0032] The preparation steps of perovskite solar cells are as follows: (1) Device structure: ITO / NiO x / Cs 0.05 (FA 0.95 MA 0.05 ) 0.95 Pb(I 0.95 Br 0.05 )3 / ETL / BCP / Ag. This is a trans-structure, with the functional layers being, in order, transparent conductive substrate / hole transport layer / light absorbing layer / electron transport layer / buffer layer / counter electrode layer. The BCP acts as a buffer layer, preventing holes from being transported to the interface and recombining with electrons.

[0033] (2) The ITO glass substrate was ultrasonically cleaned with a cleaning agent for 30 minutes, and then ultrasonically cleaned with deionized water for 20 minutes, acetone for 10 minutes, and isopropyl alcohol for 10 minutes. Finally, it was blown dry with nitrogen and stored for later use.

[0034] (3) Commercially available NiO x Nanoparticles (manufacturer: Beijing Huamin New Materials Technology Co., Ltd., product name: low-temperature nanocrystalline NiO powder, catalog number: HM-B-009-S) were dispersed in deionized water to prepare a 20 mg / mL dispersion. The dispersion was spin-coated on an ITO glass substrate at 4000 rpm for 30 s and then annealed at 100°C for 20 min.

[0035] (4) According to Cs 0.05 (FA 0.95 MA 0.05 ) 0.95 Pb(I 0.95 Br 0.05 )3 stoichiometric ratio, CsI, FAI, MABr, PbI2, PbBr2 were weighed in turn to prepare a 1.5 mol / L solution (the solvent was a DMF / DMSO mixture, DMF:DMSO=4:1 by volume), and the mixed solution was placed on a magnetic stirrer and stirred at room temperature until completely dissolved; the mixture was spin-coated on the ITO / NiO substrate at 1000 rpm for 10 s and 5000 rpm for 20 s. x In the last 5 seconds after spin coating, 150 μL of chlorobenzene was added to promote the crystallization of the perovskite film, and then annealed at 100 °C for 30 min.

[0036] (5) Example 1 is prepared on the surface of the perovskite layer to obtain an electron transport layer.

[0037] (6) BCP was dissolved in isopropanol to prepare a 0.5 mg / mL solution, which was spin-coated on the surface of the electron transport layer at 6000 rpm for 30 s, and then annealed at 80 °C for 10 min.

[0038] (7) The battery prepared in steps (1) to (6) is silver-plated with a thickness of about 100 nm and an effective area of 0.101 cm 2 .

[0039] Comparative Example 1 The preparation method is the same as that of Example 2, except that step (1) in Example 1 is modified to only weigh C 60 The powder was then used to prepare the solution, and the photovoltaic device was named SP-C 60 .

[0040] The calculation formula for photoelectric conversion efficiency is as follows: photoelectric conversion efficiency = open circuit voltage × short circuit current density × fill factor.

[0041] The perovskite solar cell device prepared in Example 1 is JV Curves such as Figure 1 As shown, it can be seen that C 60 The optimal mass ratio of corannulene to 1:0.02 is 1, corresponding to a maximum photoelectric conversion efficiency of 21.69%, an open circuit voltage of 1.09 V, and a short-circuit current density of 24.43 mA·cm -2 , the filling factor is 0.81. Based on Example 1 (C 60 : corannulene = 1:0.02) and the perovskite solar cell device prepared in Comparative Example 1 JV Curves such as Figure 2 As shown in Figure 1, the perovskite solar cell photoelectric conversion efficiency of Comparative Example 1 is 13.37%, the open circuit voltage is 0.96 V, and the short circuit current density is 22.32 mA·cm -2 , the filling factor is 0.62.

[0042] The atomic force microscope morphology of the films prepared in Example 1 of the present invention and Comparative Example 1 is as follows: Figure 3 As shown. Figure 3 On the one hand, the surface roughness of CC films is significantly lower than that of SP-C 60 film, which is due to C 60 The solubility of SP-C is poor, and it is easy to aggregate and crystallize during the film formation process. 60 A large number of island-like fullerene aggregates appeared on the film surface, destroying the film morphology and uniformity, which will lead to a decrease in battery performance. On the other hand, the surface roughness of CC film decreased with the increase of corannulene introduction. This is because the solubility of corannulene is high, which promotes the C 60 Improvements in solubility and film-forming properties are conducive to achieving better photovoltaic performance.

[0043] The surface current of the films prepared in Example 1 and Comparative Example 1 is as follows: Figure 4 As shown. Figure 4 When the doping amount of corannulene is small, the surface current value of CC film is similar to that of C 60 The film is comparable and has good conductivity. When the doping amount of corannulene is large, the surface current value of the CC film decreases slightly, which may be due to the self-assembly of the excess corannulene, thereby hindering the original electron transport path in the film.

[0044] In Example 1 of the present invention, C 60 The liquid phase H NMR spectrum of the chemical reaction with corannulene is as follows Figure 5 As shown. 60There are no hydrogen atoms on the surface, so the signal in the H NMR spectrum comes only from the hydrogen atoms on the periphery of corannulene. Figure 5 In the nuclear magnetic hydrogen spectrum, it can be clearly found that the chemical shift occurs in the low-field direction, proving that C 60 Chemical interaction between hydroxybenzoic acid and corannulene.

[0045] In Example 1 of the present invention, C 60 The fluorescence spectrum of the charge transfer reaction between the cyclopentane and corannulene is as follows: Figure 6 As shown. 60 At room temperature, the fluorescence is extremely weak and difficult to monitor. Figure 6 The fluorescence emission peak in is attributed to corannulene. Figure 6 It can be clearly found that after adding C 60 After that, the fluorescence emission peak intensity of corannulene decays. This is because the corannulene molecules transfer energy to C 60 molecules, which quenched the fluorescence of corannulene, proving that C 60 and charge transfer between corannulene.

[0046] From the above results, it can be seen that the C 60 -Corannulene composite film can achieve C 60 The electron transport layer is prepared by liquid phase film formation and has high photoelectric conversion efficiency, making it a very promising electron transport layer.

[0047] The above examples are used to illustrate the present invention, which are only used to help understand the present invention and are not intended to limit the present invention. Those skilled in the art can make several simple deductions, modifications or substitutions based on the concept of the present invention.

Claims

1. A C 60 - A method for preparing a corannulene composite film, characterized in that: The specific steps include: (1) Weigh C according to a certain mass ratio 60 and corannulene powder, adding an appropriate amount of mixed solvent; (2) Place the solution at a certain temperature and stir for a certain period of time until the powder is completely dissolved to obtain a clear solution. Wait until the solution temperature drops to room temperature and then set aside; (3) Using liquid phase preparation method to obtain C 60 -corannulene composite film, and annealing the film at a certain temperature for a certain time until the solvent is completely evaporated.

2. The preparation method according to claim 1, characterized in that In step (1), C 60 The mass ratio of corannulene to 1: (0.01~0.5).

3. The preparation method according to claim 1, characterized in that The mixed solvent consists of solvent A and solvent B, and the volume ratio of solvent A to solvent B in the mixed solvent is 1:(0.001-0.1), wherein solvent A is one of carbon disulfide, dichloromethane, chloroform, benzene, toluene, chlorobenzene, o-dichlorobenzene, and m-trimethylbenzene, and solvent B is one of N,N'-dimethylformamide, dimethyl sulfoxide, methanol, ethanol, trifluoroethanol, isopropanol, and deionized water.

4. The preparation method according to claim 1, characterized in that In step (2), the stirring temperature is 20-80° C., the stirring time is 0.5-4 hours, and the stirring is carried out under nitrogen protection.

5. The preparation method according to claim 1, characterized in that In step (3), the liquid phase preparation method includes spin coating, blade coating, spray coating or slit coating, the annealing temperature is 60-120° C., and the annealing time is 5-60 minutes.

6. C obtained by the preparation method according to any one of claims 1 to 5 60 -corannulene composite film.

7. A method of using the C according to claim 6 60 -Perovskite solar cell prepared by corannulene composite film, characterized in that, The invention comprises a transparent conductive substrate, a hole transport layer, a perovskite layer, an electron transport layer, a buffer layer and a counter electrode layer stacked in sequence, wherein the electron transport layer is C 60 -corannulene composite film.

8. The perovskite solar cell according to claim 7, characterized in that The transparent conductive substrate is one of an indium tin oxide ITO / glass substrate, a fluorine-doped tin oxide FTO / glass substrate, an ITO / polyethylene naphthalate PEN substrate, and an ITO / polyethylene terephthalate PET substrate.

9. The perovskite solar cell according to claim 7, characterized in that The hole transport layer is one of nickel oxide, polytriphenylamine, PEDOT:PSS, and (2-(9H-carbazol-9-yl)ethyl)phosphonic acid; the perovskite layer is one of MAPbI3, FAPbI3, CsPbI3, Cs x (FA y MA 1-y ) 1-x Pb(I z Br 1-z )One of 3.

10. The perovskite solar cell according to claim 7, characterized in that The buffer layer is one of bathocuproin, lithium fluoride, and fullerene derivatives; and the counter electrode layer is one of Ag, Au, Cu, and C.

Images