Preparation method of surface modified perovskite material and application of surface modified perovskite material in perovskite solar cell

Abstract

The invention belongs to the field of solar cells, and particularly relates to preparation of a surface-modified perovskite material and a perovskite solar cell. According to the invention, bipyridine is adopted as a surface modification material, a halide perovskite semiconductor material subjected to surface modification passivation is selected as a photosensitive layer, and the bipyridine and the halide perovskite semiconductor material are applied to preparation of the perovskite solar cell. The surface-modified perovskite semiconductor material effectively reduces non-radiative recombination and improves electron extraction, thereby reducing charge transfer loss. The open-circuit voltage and the filling factor of the prepared perovskite solar cell are obviously increased, and the photoelectric conversion efficiency is obviously improved.

Description

Technical Field

[0001] The invention relates to a battery prepared by using a bipyridine molecule surface-modified organic-inorganic hybrid perovskite semiconductor material as a photosensitive layer, and belongs to the field of semiconductor devices synthesized by semiconductor materials, perovskite solar cells and photosensitive devices. Background Art

[0002] Perovskite solar photovoltaic devices are batteries that use n-type and p-type semiconductor materials as carrier transport layers and metal halide perovskites as photosensitizers. As an emerging photovoltaic technology that has emerged in the past decade, it has achieved great success in this field due to its excellent photovoltaic performance and low preparation cost. However, despite the many advantages of perovskite photovoltaic devices, it still faces major development obstacles, especially non-radiative recombination and ion migration caused by interface trap states, which may cause performance to degrade over time.

[0003] There have been many studies showing that surface treatment is a key strategy to overcome the inherent challenges faced by perovskite photovoltaic devices, thereby significantly improving efficiency and stability. By optimizing the interface between the perovskite semiconductor material and the charge transport layer, organic compounds and polymer materials have been developed to stabilize interface anomalies and ions, establish chemical bonds to passivate defects and reduce ion migration. In addition, these organic compounds can fine-tune the electrical properties at the interface, including the work function of the perovskite surface, the electron transfer efficiency, and the energy disorder between the perovskite layer and the transport layer. Surface modification can be used to generate a back surface field that supports electron extraction, or post-treatment of the perovskite film can be introduced to enhance the interface properties. Strategies and processes that can both passivate defects and fine-tune the energy structure of the perovskite surface can also be developed. Summary of the invention

[0004] In view of the shortcomings of the surface properties of perovskite semiconductor materials in the battery, in order to optimize the interface between it and the charge transport layer, the present invention uses the surface binding properties of 2,2'-bipyridine molecules and adopts a simple and effective method to construct pin inverted perovskite solar cells. This molecule has been proven to effectively reduce non-radiative recombination and improve electron extraction, thereby minimizing charge transport losses. The application of this method significantly improves device efficiency, and the open circuit voltage and fill factor are significantly increased.

[0005] Terminology Note:

[0006] FAI: Formamidine iodide

[0007] MABr: Methylammonium bromide

[0008] CsI: Cesium Iodide

[0009] PbI 2 :Lead iodide

[0010] PbB 2 :Lead bromide

[0011] MeO-2PACz: [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid

[0012] BCP: Bathocuproin, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline

[0013] C60: Fullerene

[0014] DMF: N, N-dimethylformamide

[0015] DMSO: dimethyl sulfoxide

[0016] IPA: Isopropyl alcohol

[0017] CB: Chlorobenzene

[0018] PSCs: Perovskite Solar Cells

[0019] The technical solution of the present invention is as follows:

[0020] A solar cell is prepared based on bipyridine modified perovskite semiconductor material, the cell structure is as follows Figure 1 As shown, it includes an ITO conductive substrate 1, a self-assembled monomolecular hole transport layer 2, a perovskite semiconductor layer (2,2'-bipyridine modified) 3, a C60 / BCP electron transport layer 4 and a metal counter electrode layer 5 which are arranged in sequence from bottom to top.

[0021] Preferably according to the present invention, the conductive substrate is an ITO conductive glass substrate, that is, an indium tin oxide transparent conductive glass substrate.

[0022] Preferably according to the present invention, the resistance of the conductive substrate is <10 ohm / sq and the thickness is 150 nm.

[0023] Preferably according to the present invention, the self-assembled monomolecular hole transport layer is a MeO-2PACz layer prepared by a solution method.

[0024] According to a preferred embodiment of the present invention, the perovskite composition in the perovskite semiconductor layer is (FA 0.98 MA 0.02 ) 0.95 Cs 0.05 Pb(I 0.98 Br 0.02 ) 3 , thickness is 200-400nm.

[0025] According to the preferred embodiment of the present invention, the (FA 0.98 MA 0.02 ) 0.95 Cs0.05 Pb(I 0.98 Br 0.02 ) 3 The perovskite layer is prepared by a one-step solution deposition anti-solvent method.

[0026] Preferably, according to the present invention, the method for preparing the 2,2'-bipyridine-modified perovskite layer is to deposit a trace amount of 2,2'-bipyridine on the perovskite film.

[0027] Preferably according to the present invention, the C60 / BCP layer is formed by vacuum thermal evaporation and has a thickness of 20-30 nm.

[0028] Preferably according to the present invention, the metal counter electrode is a silver counter electrode; and the thickness of the metal counter electrode layer is 80-100 nm.

[0029] The method for preparing the above-mentioned efficient and stable perovskite solar cell comprises the steps of:

[0030] (1) Pretreatment of conductive substrate;

[0031] (2) spin coating deposition and annealing of a self-assembled monomolecular hole transport layer;

[0032] (3) Using the solution method, PbI 2 、PbBr 2 , CsI, FAI and MABr are used as reaction precursors, dissolved in DMF:DMSO to prepare a precursor solution, and then annealed to obtain a perovskite semiconductor layer; then a certain amount of bipyridine is spin-coated onto the perovskite film and annealed.

[0033] (4) vacuum thermal evaporation deposition of C60 and BCP layers on the substrate;

[0034] (5) The silver counter electrode is evaporated by vacuum deposition to obtain a perovskite cell.

[0035] Preferably according to the present invention, in step (1), the pretreatment method of the conductive substrate is as follows: washing and drying the conductive substrate, and finally subjecting it to ultraviolet ozone treatment.

[0036] Preferably, the washing is to ultrasonically clean the purchased etched conductive substrate in a detergent, deionized water, acetone and isopropanol in turn at room temperature for 20-30 minutes; the ultraviolet ozone treatment temperature is room temperature and the treatment time is 20 minutes.

[0037] Preferably, in step (2), the spin coating is to use a coating machine to spin coat the ethanol solution of MeO-2PACz on the conductive substrate, the spin coating speed is 2000-3000 rpm, the spin coating time is 20-30 seconds, and then annealing is performed.

[0038] According to the present invention, in step (2), the concentration of the MeO-2PACz ethanol solution is 0.5 mg / mL, and 80 μL of the solution is taken each time for spin coating.

[0039] Preferably according to the present invention, in step (2), the annealing temperature is 100° C. and the annealing time is 10 minutes.

[0040] According to the preferred embodiment of the present invention, in step (3), the one-step solution deposition anti-solvent method is to deposit PbI 2 、PbBr 2 , CsI, FAI and MABr were dissolved in a DMF:DMSO (5:1 / v:v) mixed solvent to form a 1.73M solution. 80 μL of the perovskite solution was spin-coated on the substrate treated in step (2) at a speed of 1000 rpm for 10 seconds, and then spin-coated at a speed of 5000 rpm for 40 seconds. 10 seconds before the end of the spin coating process, 350 μL of CB was dropped into the center of the film. Then, it was annealed at 100°C for 20 minutes to obtain a perovskite semiconductor material with a composition of (FA 0.98 MA 0.02 ) 0.95 Cs 0.05 Pb(I 0.98 Br 0.02 ) 3 .

[0041] Preferably, in step (3), the step of spin coating the bipyridine onto the perovskite film comprises dissolving a certain amount of 2,2'-bipyridine in CB (concentration 0.5-1.5 mg / mL), spin coating the perovskite film at a speed of 4000 rpm for 30 seconds, and then annealing on a hot plate at 100°C for 5 minutes.

[0042] According to the preferred embodiment of the present invention, in step (4), the vacuum thermal evaporation deposition of C60 and BCP layers is carried out at a vacuum degree of less than 5×10 -4 Under Pa, the evaporation rate of C60 is 0.05nm / s and the thickness is 20nm; the evaporation rate of BCP is 0.05nm / s and the thickness is 6nm.

[0043] According to the preferred embodiment of the present invention, in step (5), the vacuum deposition and evaporation of the silver counter electrode is carried out at a vacuum degree of less than 5×10 -4 Pa, the evaporation rate of silver is 0.1nm / s.

[0044] The technical features and beneficial effects of the present invention are as follows:

[0045] 1. The surface binding properties of 2,2'-bipyridine molecules used in the present invention are used to manufacture perovskite solar cells.

[0046] 2. The organic-inorganic hybrid perovskite semiconductor material used in the present invention is modified by introducing 2,2'-bipyridine molecules to effectively reduce non-radiative recombination and optimize electron extraction, thereby minimizing charge transfer losses.

[0047] 3. The photoelectric performance of the battery prepared by using 2,2'-bipyridine to modify the perovskite semiconductor material is significantly enhanced. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 A schematic diagram of the structure of a perovskite solar cell provided for an embodiment of the invention of benzene.

[0049] Figure 2 1 is the X-ray diffraction (XRD) pattern of the perovskite semiconductor photosensitive material in Examples 1-4 of the present invention.

[0050] Figure 3 1 is the photoluminescence (PL) spectrum of the perovskite semiconductor photosensitive material in Examples 1-4 of the present invention.

[0051] Figure 4 The impedance curves of the batteries prepared with the perovskite semiconductor photosensitive materials in Examples 3 and 1 of the present invention.

[0052] Figure 5 The photoelectric performance curves of the cells prepared with the perovskite semiconductor photosensitive materials in Examples 3 and 1 of the present invention. DETAILED DESCRIPTION

[0053] The present invention is further described below by means of specific examples, but is not limited thereto.

[0054] Unless otherwise specified, the raw materials used in the examples are conventional raw materials and can be obtained commercially; the methods used in the examples are all prior arts unless otherwise specified.

[0055] Example 1

[0056] A method for preparing a perovskite solar cell using a surface-modified perovskite semiconductor material as a photosensitive layer, comprising the steps of:

[0057] (1) The conductive surface of the ITO conductive glass is ultrasonically cleaned at room temperature for 20-30 minutes using a cleaning agent, deionized water, acetone, and isopropanol, respectively. After drying, the surface is placed in a UV-ozone treatment device and treated at room temperature for 20 minutes.

[0058] (2) Prepare a 0.5 mg / mL MeO-2PACz solution in ethanol. Spin-coat 80 μL of the prepared MeO-2PACz solution onto an ITO substrate and anneal at 100° C. for 10 minutes.

[0059] (3) Perovskite semiconductor material layer, CsI, FAI, MABr, PbI 2 and PbBr 2 A 1.73 M perovskite precursor solution was prepared in 1 ml of DMF:DMSO (5:1 / v:v) mixed solvent with the chemical formula (FA 0.98 MA 0.02 ) 0.95 Cs 0.05 Pb(I 0.98 Br 0.02 ) 3 80 μL of the perovskite precursor solution was spin coated onto ITO / MeO-2PACz at 1000 rpm for 10 s, followed by a spin coating at 5000 rpm for 40 s. 350 μL of CB was dropped into the center of the film 10 s before the end of the spin coating process. The subsequently deposited perovskite film was annealed on a hot plate at 100 °C for 20 min.

[0060] (4) When the vacuum degree is less than 5×10 -4 A 20 nm C60 layer and a 6 nm BCP layer were thermally evaporated at a rate of 0.05 nm / s under a high vacuum of 2.34 Å.

[0061] (5) Vacuum evaporated silver counter electrode, in a vacuum degree less than 5×10 -4 Pa, the evaporation rate of silver is 0.1nm / s, and the thickness is about 100nm. That is, an all-inorganic perovskite solar cell is obtained.

[0062] The (FA 0.98 MA 0.02 ) 0.95 Cs 0.05 Pb(I 0.98 Br 0.02 ) 3 The X-ray diffraction pattern of Figure 2 The prepared sample shows a series of tetragonal perovskite characteristic diffraction peaks (001), (011), (002), (012). The photoluminescence spectrum of the material is shown in Figure 3 As shown in Figure 1, a characteristic peak appears at 810 nm. The impedance curve of the battery prepared with this semiconductor material as a photosensitizer is shown in Figure 1 Figure 4 The composite impedance of the display device is small, and the photoelectric performance of the battery is Figure 5 As shown, the battery open circuit voltage is 1.119 V and the short circuit current density is 24.57 mA cm -2 , the filling factor is 77.07% and the photoelectric conversion efficiency is 21.21%.

[0063] Example 2

[0064] A method for preparing a perovskite solar cell using a surface-modified perovskite semiconductor material as a photosensitive layer, as described in Example 1, except that:

[0065] In step (3), the step is followed by spin coating of bipyridine onto the perovskite film by dissolving 0.5 mg / mL of 2,2'-bipyridine in CB, spin coating the perovskite film at 4000 rpm for 30 seconds, and then annealing on a hot plate at 100° C. for 5 minutes.

[0066] The bipyridine-modified (FA) prepared in step (3) of this example 0.98 MA 0.02 ) 0.95 Cs 0.05 Pb(I 0.98 Br 0.02 ) 3 The X-ray diffraction pattern of Figure 2 The prepared sample does not change the characteristic diffraction peak of the perovskite semiconductor material itself. The photoluminescence spectrum of the semiconductor material in this embodiment is shown in Figure 3 As shown, the characteristic peak at 810 nm has a greater intensity than that of the material described in Example 1, indicating that the electron excitation efficiency in the semiconductor material is improved.

[0067] Example 3

[0068] A method for preparing a perovskite solar cell using a surface-modified perovskite semiconductor material as a photosensitive layer, as described in Example 1, except that:

[0069] In step (3), the step is followed by spin coating of bipyridine onto the perovskite film by dissolving 2,2'-bipyridine at a concentration of 1.0 mg / mL in CB, spin coating the perovskite film at a speed of 4000 rpm for 30 seconds, and then annealing on a hot plate at 100° C. for 5 minutes.

[0070] The bipyridine-modified (FA) prepared in step (3) of this example 0.98 MA 0.02 ) 0.95 Cs 0.05 Pb(I 0.98 Br 0.02 ) 3 The X-ray diffraction pattern of Figure 2 The prepared sample does not change the characteristic diffraction peak of the perovskite semiconductor material itself. The photoluminescence spectrum of the semiconductor material in this embodiment is shown in Figure 3 As shown in Figure 1, the characteristic peak at 810 nm is stronger than that of the materials described in Examples 1, 2 and 4, indicating that the electronic excitation efficiency of the semiconductor material in this example is the highest. At the same time, the impedance curve of the battery prepared by using the semiconductor material in this example as a photosensitizer ( Figure 4) shows that the composite impedance of the device is significantly larger than that of Example 1, and the battery has the best photoelectric performance ( Figure 5 ), the battery open circuit voltage is 1.168V, and the short circuit current density is 25.08mAcm -2 , the filling factor is 81.49% and the photoelectric conversion efficiency is 23.87%.

[0071] Example 4

[0072] A method for preparing a perovskite solar cell using a surface-modified perovskite semiconductor material as a photosensitive layer, as described in Example 1, except that:

[0073] In step (3), the step is followed by spin coating of bipyridine onto the perovskite film by dissolving 2,2'-bipyridine at a concentration of 1.5 mg / mL in CB, spin coating the perovskite film at a speed of 4000 rpm for 30 seconds, and then annealing on a hot plate at 100° C. for 5 minutes.

[0074] The bipyridine-modified (FA) prepared in step (3) of this example 0.98 MA 0.02 ) 0.95 Cs 0.05 Pb(I 0.98 Br 0.02 ) 3 The X-ray diffraction pattern of Figure 2 The prepared sample does not change the characteristic diffraction peak of the perovskite semiconductor material itself. The photoluminescence spectrum of the semiconductor material in this embodiment is shown in Figure 3 As shown, the characteristic peak at 810 nm has a greater intensity than that of the materials of Examples 1 and 2, indicating that the electron excitation efficiency in the semiconductor material is improved.

Claims

1. A perovskite solar cell is prepared by using a bipyridine surface-modified perovskite semiconductor material as a photosensitive layer, comprising an ITO conductive substrate, a self-assembled monomolecular hole transport layer, a perovskite semiconductor layer (modified with 2,2'-bipyridine), a C60 / BCP electron transport layer, and a metal counter electrode layer arranged in sequence from bottom to top.

2. The perovskite solar cell according to claim 1, characterized in that: The conductive substrate is an ITO conductive glass substrate, that is, an indium tin oxide transparent conductive glass substrate.

3. The bipyridine surface modified perovskite semiconductor material according to claim 1 is used as a photosensitive layer to prepare a solar cell, characterized in that: Includes one or more of the following conditions: i. The resistance of the conductive substrate is <10 ohm / sq and the thickness is 150 nm. ii. The self-assembled monomolecular hole transport layer MeO-2PACz. iii. The perovskite composition in the perovskite semiconductor layer is (FA 0.98 MA 0.02 ) 0.95 Cs 0.05 Pb(I 0.98 Br 0.02 )3, thickness is 200-400nm. iv. According to a preferred embodiment of the present invention, the preparation method of the perovskite layer is a one-step solution deposition anti-solvent method. v. According to a preferred embodiment of the present invention, the preparation method of the bipyridine surface-modified perovskite layer is to deposit and modify a trace amount of 2,2'-bipyridine on the perovskite film. vi. Preferably according to the present invention, the C60 / BCP layer is evaporated by vacuum thermal evaporation and has a thickness of 20-30 nm. vii. Preferably according to the present invention, the metal counter electrode is a silver counter electrode; and the thickness of the metal counter electrode layer is 80-100 nm.

4. A method for preparing a solar cell using the bipyridine surface-modified perovskite semiconductor material as a photosensitive layer as claimed in any one of claims 1 to 3, comprising the steps of: (1) Pretreatment of conductive substrate; (2) spin coating deposition and annealing of a self-assembled monomolecular hole transport layer; (3) A solution method is used, where PbI2, PbBr2, CsI, FAI and MABr are used as reaction precursors, dissolved in DMF:DMSO to prepare a precursor solution, and then annealed to obtain a perovskite semiconductor layer; a certain amount of bipyridine is then spin-coated onto the perovskite film and annealed. (4) vacuum thermal evaporation deposition of C60 and BCP layers on the substrate; (5) The silver counter electrode is evaporated by vacuum deposition to obtain a perovskite cell.

5. The method for preparing a solar cell using the bipyridine surface modified perovskite semiconductor material as a photosensitive layer according to claim 4, characterized in that: i. In step (1), the pretreatment method of the conductive substrate is as follows: washing and drying the conductive substrate, and finally subjecting it to ultraviolet ozone treatment. ii. In step (1), the washing is to ultrasonically clean the purchased etched conductive substrate in a detergent, deionized water, acetone and isopropanol in turn at room temperature for 20-30 minutes; the ultraviolet ozone treatment temperature is room temperature and the treatment time is 20 minutes. iii. In step (2), the spin coating is performed by using a coating machine to spin coat the ethanol solution of MeO-2PACz on the conductive substrate at a spin coating speed of 2000-3000 rpm for 20-30 seconds, followed by annealing. iv. In step (2), the concentration of MeO-2PACz ethanol solution is 0.5 mg / mL, and 80 μL of solution is taken each time for spin coating. v. In step (2), the annealing temperature is 100° C. and the annealing time is 10 minutes.

6. The method for preparing a solar cell using the bipyridine surface modified perovskite semiconductor material as a photosensitive layer according to claim 4, characterized in that: In step (3), one or more of the following conditions are included: i. The one-step solution deposition anti-solvent method is to dissolve PbI2, PbBr2, CsI, FAI and MABr in a DMF:DMSO (5:1 / v:v) mixed solvent to form a 1.73M solution, and spin-coat 80 μL of the perovskite solution onto the substrate treated in step (2) at a speed of 1000 rpm for 10 seconds, and then spin-coat at a speed of 5000 rpm for 40 seconds. 10 seconds before the end of the spin coating process, 350 μL of CB is dripped into the center of the film. Then anneal at 100°C for 20 minutes to obtain a perovskite semiconductor material composition of (FA 0.98 MA 0.02 ) 0.95 Cs 0.05 Pb(I 0.98 Br 0.02 )3. ii. Then, the bipyridine is spin-coated onto the perovskite film by dissolving a certain amount of 2,2'-bipyridine in CB (concentration 0.5-1.5 mg / mL), spin-coating the film onto the perovskite film at a speed of 4000 rpm for 30 seconds, and then annealing on a hot plate at 100° C. for 5 minutes.

7. The method for preparing a solar cell using the bipyridine surface modified perovskite semiconductor material as a photosensitive layer according to claim 4, characterized in that: In step (4), the vacuum thermal evaporation deposition of C60 and BCP layers is carried out at a vacuum degree of less than 5×10 -4 Under Pa, the evaporation rate of C60 is 0.05nm / s and the thickness is 20nm; the evaporation rate of BCP is 0.05nm / s and the thickness is 6nm.

8. The method for preparing a solar cell using the bipyridine surface modified perovskite semiconductor material as a photosensitive layer according to claim 4, characterized in that: In step (5), the vacuum deposition and evaporation of the silver counter electrode is carried out at a vacuum degree of less than 5×10 - 4 Pa, the evaporation rate of silver is 0.1nm / s.

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