Broadband-gap perovskite thin film based on interface engineering regulation and control as well as preparation method and application of wide-band-gap perovskite thin film

Abstract

The invention discloses a wide-band-gap perovskite thin film based on interface engineering regulation and control and a preparation method and application thereof. The preparation method comprises the following steps: dissolving 4-hydroxyphenylethyl amine iodide powder in an FA0. 8Cs0. 2Pb (I0. 6Br0. 4) 3 precursor solution to obtain a wide-band-gap perovskite precursor solution with the doping concentration of 0.5-2mol%; the wide-band-gap perovskite thin film is obtained by performing two-step spin coating on the wide-band-gap perovskite precursor solution on a substrate and then performing two-step annealing, and when the wide-band-gap perovskite thin film is applied to a wide-band-gap perovskite solar cell or a laminated wide-band-gap perovskite solar cell, the stability and the performance of a device can be improved. The method is mainly characterized by improving the uniformity of the film, reducing non-radiative recombination, prolonging the service life of current carriers, improving filling factors and current density and improving the photoelectric conversion efficiency. According to the invention, generation of a two-dimensional phase is inhibited, a dipole layer is generated on an interface, energy level matching between a perovskite light absorption layer and an electron transport layer is promoted, interface connection is enhanced, and carrier transport capability is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of wide bandgap perovskite cells, and in particular relates to a wide bandgap perovskite film based on interface engineering regulation, and a preparation method and application thereof. Background Art

[0002] In recent years, single-junction perovskite solar cells have developed rapidly, and their efficiency has approached the theoretical efficiency limit, making it increasingly difficult to further improve the efficiency. Researching and developing tandem perovskite solar cells is an effective way to reduce thermal relaxation and break through the theoretical efficiency limit. Since wide-bandgap perovskite solar cells (WBGPSCs) are components of all-perovskite two-terminal tandem solar cells (TSCs), in order to improve the efficiency of tandem solar cells, it is crucial to prepare efficient and stable WBGPSCs. However, WBGPSCs suffer from severe interface transmission losses, which greatly hinders the development of TSCs. Therefore, finding an effective strategy to minimize the interface losses of WBGPSCs is of great significance for the development of efficient tandem devices.

[0003] Since PSCs are structural devices composed of a perovskite light-absorbing layer, a charge transport layer, and electrodes, the multilayer stacking structure implies various interface contacts. The properties of these interfaces directly affect charge transport, which is crucial for high-performance PSCs.

[0004] On the one hand, interface non-radiative recombination and mismatched energy levels can lead to severe transmission losses, thus limiting the efficiency of WBGPSCs. On the other hand, interface defects may also damage the stability of the device. Therefore, interface engineering is one of the most effective methods to achieve high performance and long-term stability of perovskite solar cells. For example, a series of fluorine-doped succinic acid derivatives are introduced into the bottom interface of perovskite. Among them, tetrafluorosuccinic acid (TFSA) has a symmetrical molecular structure and strong electronegativity, and is proven to be the best interface regulator among the selected functional molecules. It regulates the morphological arrangement of MeO-2PACz, homogenizes its surface contact potential, and successfully 2 A photoelectric conversion efficiency of 25.92% was achieved in the inverted device.

[0005] Although some studies have pointed out methods to optimize the interface, such as forming a two-dimensional phase on the perovskite surface (e.g. using phenylethylamine cation PEA), + ) inhibits phase separation and non-radiative recombination, thereby solving the problem of severe open-circuit voltage loss in wide-bandgap perovskite solar cells. However, the electron blocking properties of the two-dimensional ligands have a negative impact on carrier transport. In other words, there is still a problem of poor interface energy level alignment between the perovskite and the electron transport layer (ETL) or hole transport layer (HTL), which leads to non-radiative recombination of photogenerated carriers and reduces the open-circuit voltage (V OC) and fill factor. Furthermore, halide ions (such as iodide ions) readily migrate under light and thermal stress, leading to increased ion vacancies and defect density at the interface, thus affecting interface stability and device performance. Therefore, further research into transmission losses has a significant impact on improving the efficiency of perovskite solar cells. Summary of the Invention

[0006] The purpose of this section is to summarize some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of this application to avoid obscuring the purpose of this section, the abstract and the title of the invention, and such simplifications or omissions should not be used to limit the scope of the present invention.

[0007] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0008] Therefore, the purpose of the present invention is to overcome the deficiencies in the prior art and provide a method for preparing a wide-bandgap perovskite film based on interface engineering regulation.

[0009] In order to solve the above technical problems, the present invention provides the following technical solutions: comprising:

[0010] 4-Hydroxyphenethylammonium iodide dissolved in FA 0.8 Cs 0.2 Pb(I 0.6 Br 0.4 )3 to obtain a wide bandgap perovskite precursor solution from the precursor solution;

[0011] The wide band gap perovskite precursor solution is spin-coated on the substrate in two steps and then annealed in two steps to obtain a wide band gap perovskite film.

[0012] As a preferred solution of the method for preparing a wide bandgap perovskite film based on interface engineering regulation of the present invention, the doping concentration of 4-hydroxyphenethylammonium iodide in the wide bandgap perovskite precursor solution is 0.5 to 2 mol%.

[0013] As a preferred embodiment of the method for preparing a wide-bandgap perovskite film based on interface engineering regulation described in the present invention, the first step of the two-step spin coating has a spin coating speed of 450 to 500 rpm and a time of 1 to 2 s; the second step of the spin coating has a spin coating speed of 4000 to 5000 rpm and a time of 60 to 65 s.

[0014] As a preferred solution of the method for preparing a wide bandgap perovskite film based on interface engineering regulation of the present invention, wherein: ether is added dropwise as an anti-solvent at 20 to 22 seconds during the second spin coating step.

[0015] It should be noted that when the spin coating time exceeds this range, the film may easily break, thereby affecting its performance.

[0016] As a preferred embodiment of the method for preparing a wide bandgap perovskite film based on interface engineering regulation according to the present invention, the ratio of the amount of ether added to the wide bandgap perovskite precursor solution is 70-80:8-9 (μL).

[0017] As a preferred embodiment of the method for preparing a wide bandgap perovskite film based on interface engineering regulation according to the present invention, the first step of the two-step annealing is annealing at 65°C for 1.5 to 2 minutes, and the second step is annealing at 95 to 100°C for 9.5 to 10 minutes.

[0018] Another object of the present invention is to provide a wide bandgap perovskite thin film material.

[0019] Another object of the present invention is to provide an application of a wide bandgap perovskite thin film material in the preparation of a wide bandgap perovskite solar cell.

[0020] Another object of the present invention is to provide a wide bandgap perovskite solar cell, which comprises, from bottom to top,

[0021] ITO substrate layer, thickness of 0.6-0.8 mm, made of ITO conductive glass;

[0022] Self-assembled molecular layer, thickness 0.1-1.5 nm, material 4PADCB;

[0023] A wide bandgap perovskite light-absorbing layer with a thickness of 400 to 500 nm, made of the above-mentioned wide bandgap perovskite thin film material;

[0024] Electron transport layer, thickness is 10~30nm, material is C 60 ;

[0025] A hole blocking layer with a thickness of 6 to 8 nm or 10 to 20 nm, made of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline or atomic layer deposited SnO2;

[0026] The metal electrode layer has a thickness of 100 to 200 nm and is made of silver or copper.

[0027] Another object of the present invention is to provide a laminated wide bandgap perovskite solar cell, the structure of which, from bottom to top, comprises:

[0028] ITO substrate layer, thickness of 0.6-0.8 mm, made of ITO conductive glass;

[0029] Self-assembled molecular layer, thickness 0.1-1.5 nm, material 4PADCB;

[0030] A wide bandgap perovskite light-absorbing layer having a thickness of 400 to 500 nm, made of the wide bandgap perovskite film mentioned above;

[0031] Electron transport layer, thickness is 10~30nm, material is C 60 ;

[0032] The intermediate connection layer has a thickness of 80 to 90 nm and is made of SnO2 and IZO, wherein the thickness of SnO2 is 15 to 20 nm and the thickness of IZO is 65 to 70 nm;

[0033] Hole transport layer, thickness 20-25 nm, made of PEDOT:PSS;

[0034] Narrow bandgap perovskite absorption layer, thickness 800 ~ 900nm, material (FASnI3) 0.6 (MAPbI3) 0.4 ;

[0035] Electron transport layer, thickness is 10~30nm, material is C 60 ;

[0036] A hole blocking layer with a thickness of 6 to 8 nm or 10 to 20 nm, made of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline or atomic layer deposited SnO2;

[0037] The metal electrode layer has a thickness of 100 to 200 nm and is made of silver or copper.

[0038] Beneficial effects of the present invention:

[0039] (1) The present invention uses 4-hydroxyphenylethylamine iodide (p-OHPEAI) for the first time to be doped into a wide-bandgap perovskite precursor solution, and then spin-coating the perovskite solution to obtain a doped wide-bandgap perovskite light-absorbing layer film. A dual optimization strategy is proposed by doping p-OHPEAI. On the one hand, p-OHPEAI ​​will be adsorbed parallel to the perovskite lattice surface, changing the vertical adsorption configuration of traditional PEAI, thereby inhibiting the formation of a two-dimensional phase. On the other hand, when the perovskite light-absorbing layer contacts the electron transport layer, the polar structures at both ends of p-OHPEAI ​​will form a dipole layer at the interface, further promoting energy level matching, enhancing interface connection, and improving carrier transport capability, thereby overcoming the problems of selecting two-dimensional ligands (such as using phenylethylamine cation PEA) in the prior art. + )’s electron blocking properties will have a negative impact on carrier transport. In addition, the functional groups carboxyl and amino groups on both sides of p-OHPEAI ​​in the present invention will contact and interact with the perovskite, promoting the passivation of perovskite interface defects and improving device stability and performance.

[0040] (2) Applying the wide bandgap perovskite prepared by the present invention to a stacked battery can improve the turn-on voltage and efficiency of the stacked device and enhance the stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort. Among them:

[0042] Figure 1 2 is a structural diagram of a wide-bandgap perovskite solar cell doped with 4-hydroxyphenethylammonium iodide (p-OHPEAI) in Example 1 of the present invention.

[0043] Figure 2 Scanning electron microscope images of the perovskite film surfaces obtained in Example 1, Comparative Example 1, and Comparative Example 2 of the present invention

[0044] Figure 3 X-ray photoelectron spectra of the perovskite films obtained in Example 1 and Comparative Example 2.

[0045] Figure 4 These are time-resolved photoluminescence images of the perovskite films prepared in Example 1, Comparative Example 1, and Comparative Example 2.

[0046] Figure 5 These are the X-ray diffraction patterns of the perovskite films obtained in Example 1, Comparative Example 1, and Comparative Example 2.

[0047] Figure 6 The energy band structure diagram is drawn by ultraviolet photoelectron spectroscopy (UPS) of the perovskite films obtained according to Example 1, Comparative Example 1, and Comparative Example 2.

[0048] Figure 7 This is a statistical comparison chart of the photovoltaic performance of the wide-bandgap perovskite solar cells prepared in Example 1, Comparative Example 1, and Comparative Example 2.

[0049] Figure 8 These are hysteresis scan diagrams of the wide bandgap perovskite solar cells prepared in Example 1, Comparative Example 1, and Comparative Example 2.

[0050] Figure 9 This is a comparison chart of the long-term stability of the wide-bandgap perovskite solar cells prepared in Example 1, Comparative Example 1, and Comparative Example 2.

[0051] Figure 10 This is the JV curve of the stacked perovskite solar cell obtained in Example 4. DETAILED DESCRIPTION

[0052] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0053] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0054] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive of other embodiments.

[0055] Unless otherwise specified, the raw materials used in the present invention are commonly available in the market.

[0056] Unless otherwise specified, the conventional magnetron sputtering method is used for stacking the layers of the invented perovskite battery.

[0057] The relevant performance test conditions of the present invention are:

[0058] Photoelectric conversion efficiency test:

[0059] At 100 mW cm -2 The light intensity was measured using a Keithley 2400 source meter under illumination from an AM 1.5G solar simulator (SS-F5-3A, Enlitech), and was calibrated with a standard silicon solar cell;

[0060] Steady-state power output:

[0061] By constant illumination (100 mW cm -2 ) under maximum power point tracking test, and the device is tested at N without packaging and temperature control unit 2 Test under atmosphere;

[0062] Carrier lifetime test:

[0063] The TRPL spectra were fitted using double-exponential and triple-exponential functions using a pulsed laser with a wavelength of 410 nm and an excitation frequency of 0.1 MHz.

[0064] Example 1

[0065] Reference Figure 1This embodiment provides a method for preparing a wide-bandgap perovskite solar cell doped with 4-hydroxyphenethylamine iodide (p-OHPEAI), specifically:

[0066] 1) Using ITO conductive glass with a square resistance of 15Ω, an average transmittance of >85%, and a thickness of 0.7mm as the substrate material, it was cleaned in an ultrasonic machine using detergent, deionized water, acetone, and ethanol for 15 minutes, blown dry with a nitrogen gun, and then treated with ultraviolet ozone for 20 minutes to remove surface organic matter. A clean ITO conductive glass layer was obtained, which was the pretreated ITO substrate with a thickness of about 0.7mm.

[0067] 2) 4PADCB was dissolved in anhydrous ethanol to obtain a 4PADCB solution with a concentration of 0.5 mg / mL. The 4PADCB solution was dropwise applied to the surface of an ITO substrate and spin-coated at a speed of 3000 rpm for 20 s. After spin coating, the substrate was annealed on a hot plate at 100°C for 10 min to form a self-assembled molecular layer with a thickness of approximately 1 nm.

[0068] 3) 0.4 mmol of formamidine iodine, 0.2 mmol of cesium iodide, 0.4 mmol of formamidine bromide, 0.6 mmol of lead iodide and 0.4 mmol of lead bromide were dissolved in 0.83 mL of a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) with a volume ratio of 3:1. Then, 3.2 mg of lead thiocyanate, 1 mg of potassium thiocyanate and 1 mg of formamidine thiocyanate were added to the solution to obtain FA. 0.8 Cs 0.2 Pb(I 0.6 Br 0.4 )3 precursor solution;

[0069] Dissolve p-OHPEAI ​​powder in FA 0.8 Cs 0.2 Pb(I 0.6 Br 0.4 )3 precursor solution to obtain a wide bandgap perovskite precursor solution with a p-OHPEAI ​​doping concentration of 1.0 mol%.

[0070] 4) 90 μL of the wide-bandgap perovskite precursor solution doped with p-OHPEAI ​​was dropped onto the SAM (self-assembled molecular layer) and spin-coated in two steps. The first step was performed at a speed of 500 rpm for 2 seconds, and the second step was performed at a speed of 4000 rpm for 60 seconds. At the 23rd second of the second step, 750 μL of diethyl ether was added as an antisolvent.

[0071] After the spin coating is completed, the substrate is placed on a hot plate at 65°C for annealing for 2 minutes, and then placed on a hot plate at 100°C for annealing for 10 minutes to obtain a perovskite film, which is a wide bandgap perovskite light-absorbing layer with a thickness of 450 nm.

[0072] 5) Dissolve ethylenediamine iodine powder in IPA solution to obtain a back passivation solution with a concentration of 1 mg / mL, stir at 70°C for 3 hours, and filter through a 0.22 μm PTFE filter to obtain an ethylenediamine iodine solution;

[0073] 80 μL of ethylenediamine iodine solution was dropped on the perovskite film, and then after rotating at 4000 rpm for 20 seconds, it was immediately annealed at 100°C for 5 minutes to achieve back passivation treatment.

[0074] 6) The product of step 5) was placed in a thermal evaporation chamber at 4×10 -4 Pa in a high vacuum and evaporate 20 nm of C 60 The material was used as an electron transport layer, 6 nm of BCP was evaporated as a hole blocking layer, and 100 nm of copper was evaporated as a metal electrode layer to prepare a wide bandgap perovskite solar cell doped with 1.0 mol % of 4-hydroxyphenethylammonium iodide.

[0075] Example 2

[0076] The difference between this embodiment and Example 1 is that the p-OHPEAI ​​doping concentration in the wide bandgap perovskite precursor solution in step 3) is adjusted to 0.5, 1, 1.5, and 2 mol%, respectively. The remaining steps and processes are referred to Example 1, and perovskite films and wide bandgap perovskite solar cells with different 4-hydroxyphenethylamine iodide p-OHPEAI ​​doping concentrations in this embodiment are obtained.

[0077] The performance of the wide bandgap perovskite solar cell device prepared in Example 2 was tested, and the results are shown in Table 1.

[0078] Table 1

[0079] p-OHPEAI ​​concentration (mol%) <![CDATA[V OC (V)]]> <![CDATA[J SC (mA / cm 2 )]]> FF(%) PCE (%) 0.5 1.325 17.36 80.1 18.420 1 1.344 17.42 81.9 19.246 1.5 1.331 17.21 81.3 18.617 2 1.289 17.46 80.5 18.116

[0080] As can be seen from Table 1, adjusting the concentration of the additive p-OHPEAI ​​in the wide-bandgap perovskite precursor solution has a significant effect on the performance of solar cells. This is because, on the one hand, p-OHPEAI ​​needs to cover the perovskite surface through parallel adsorption to suppress the formation of a two-dimensional phase. When the concentration is too low, the number of adsorbed molecules is insufficient to effectively suppress the two-dimensional phase, resulting in obstructed carrier transport. When the concentration is too high, it may be embedded in the perovskite lattice or aggregated at the grain boundary, destroying the crystallinity, introducing new defects, and reducing carrier mobility.

[0081] On the other hand, when the perovskite light-absorbing layer contacts the electron transport layer, the polar structures at both ends of p-OHPEAI ​​will form a dipole layer at the interface. The dipole layer formed at the interface requires sufficient molecular density to optimize energy level matching. At low concentrations, the dipole layer is sparse and cannot effectively promote carrier transport. At high concentrations, the molecules over-accumulate at the interface, forming an overly thick or disordered dipole layer, which hinders carrier extraction and increases interface resistance. Excessive molecules may self-aggregate rather than bind to defects, forming insulating regions, which in turn increases recombination centers and weakens the passivation effect.

[0082] Furthermore, the passivation of defects by carboxyl and amino groups in this application requires sufficient binding of the molecules to the defect sites. At low concentrations, defect coverage is insufficient, non-radiative recombination increases, and device efficiency and stability decrease. At high concentrations, grain growth is inhibited, resulting in finer grains, more grain boundaries, and increased carrier recombination. Therefore, only at the appropriate concentration can good technical effects be achieved.

[0083] Comparative Example 1

[0084] The difference between this comparative example and Example 1 is that p-OHPEAI ​​is not doped into FA 0.8 Cs 0.2 Pb(I 0.6 Br 0.4 )3 precursor solution, and the remaining steps and processes are all referred to Example 1 to obtain a wide-bandgap perovskite solar cell without p-OHPEAI ​​doping of this comparative example.

[0085] Comparative Example 2

[0086] The difference between this embodiment and Example 1 is that the 4-hydroxyphenethylammonium iodide (p-OHPEAI) doped in step 3) is adjusted to phenethylammonium iodide (PEAI), and the remaining steps and processes are referred to Example 1 to obtain a perovskite film doped with 1 mol% phenethylammonium iodide and a wide-bandgap perovskite solar cell in this embodiment.

[0087] Figure 2 The scanning electron microscope images of the perovskite film surfaces prepared in Example 1, Comparative Example 1 and Comparative Example 2 show that some grains on the surface of the perovskite film after doping with p-OHPEAI ​​are enlarged, and the surface of the perovskite film after doping with PEAI is smoother, but the grain size is significantly reduced due to the generation of a two-dimensional phase. Doping with p-OHPEAI ​​improves the quality of the wide bandgap film and passivates the defects.

[0088] Figure 3 The X-ray photoelectron spectra of the perovskite films obtained in Example 1 and Comparative Example 2 show that the wide bandgap perovskite film doped with PEAI still has Pb 0peak, which will act as a non-radiative recombination center and have a negative impact on the device performance, indicating that the passivation of PEAI is not sufficient; and the wide-bandgap perovskite film doped with p-OHPEAI ​​Pb 0 The peak has been significantly suppressed, indicating that the doping of p-OHPEAI ​​can achieve a better passivation effect.

[0089] Figure 4 Time-resolved photoluminescence images of the perovskite films produced in Example 1, Comparative Example 1, and Comparative Example 2 show a significant increase in the carrier lifetime of the doped perovskite films, reaching over 200 nanoseconds. This demonstrates that p-OHPEAI ​​doping can more effectively reduce the defect state density in wide-bandgap perovskite films, thereby suppressing non-radiative recombination and improving carrier lifetime.

[0090] Figure 5 The X-ray diffraction patterns (XRD) of the perovskite films obtained in Example 1, Comparative Example 1 and Comparative Example 2 show that the wide-bandgap perovskite film doped with PEAI produces a new diffraction peak, indicating that a two-dimensional phase is generated on the perovskite surface, but the wide-bandgap perovskite film doped with p-OHPEAI ​​does not produce a two-dimensional phase, indicating that the hydroxyl groups in p-OHPEAI ​​contact and interact with the perovskite, thereby inhibiting the formation of the two-dimensional phase.

[0091] Figure 6 The energy band structure diagrams are drawn using ultraviolet photoelectron spectroscopy (UPS) of the perovskite films obtained according to Example 1, Comparative Example 1, and Comparative Example 2. It can be seen that the wide-bandgap perovskite film doped with PEAI generates a two-dimensional phase, which leads to an energy level mismatch between the perovskite light-absorbing layer and the electron transport layer, thereby blocking carrier transport. However, the wide-bandgap perovskite film doped with p-OHPEAI ​​successfully suppresses the two-dimensional phase and generates a dipole layer at the interface, promoting energy level matching and carrier transport between the perovskite light-absorbing layer and the electron transport layer.

[0092] Figure 7 This is a statistical comparison chart of the photovoltaic performance of wide-bandgap perovskite solar cells prepared in Example 1, Comparative Example 1 and Comparative Example 2. It can be seen that the average values ​​of the photoelectric conversion efficiency, open-circuit voltage, short-circuit current and fill factor of the wide-bandgap device doped with p-OHPEAI ​​are higher, and the device performance repeatability is better. The maximum opening voltage of the device can reach above 1.35V, and the opening voltage loss is reduced to below 0.42V.

[0093] Figure 8 The hysteresis scan diagrams of the wide-bandgap perovskite solar cells prepared in Example 1, Comparative Example 1, and Comparative Example 2 show that p-OHPEAI ​​can more effectively passivate perovskite interface defects and improve the device performance and stability of the perovskite solar cell.

[0094] Figure 9 The wide-bandgap perovskite solar cells prepared in Example 1, Comparative Example 1, and Comparative Example 2 were stored in a nitrogen glove box. The results of testing the photoelectric conversion efficiency of the wide-bandgap perovskite solar cells as storage time increased revealed that p-OHPEAI ​​doping effectively inhibited perovskite decomposition. Clearly, even after storage for more than 1,800 hours, the efficiency of the wide-bandgap solar cells doped with p-OHPEAI ​​remained above 85% of the initial efficiency. However, after 800 hours of storage, the photoelectric conversion efficiency of the cells in Comparative Example 1 and Comparative Example 2 decreased significantly, reaching less than 80% of the initial efficiency. This demonstrates that the stability of the perovskite solar cells doped with p-OHPEAI ​​has been significantly improved.

[0095] Example 4

[0096] This embodiment provides a method for preparing a stacked perovskite cell using the perovskite film of Example 1, specifically:

[0097] 1) Prepare a passivated wide bandgap perovskite light absorbing layer by referring to steps 1) to 5) of Example 1, place it in a thermal evaporation chamber, -4 20nm C was evaporated under high vacuum of Pa 60 The material is used as an electron transport layer, and a 20nm SnO2 layer is deposited on the surface of the electron transport layer using atomic layer deposition;

[0098] 2) The product obtained in step 2) was placed in a magnetron sputtering chamber at 4×10 -4 Pa under high vacuum, sputtering was performed at 25 W for 22 min and at 30 W for 22 min to obtain a 70 nm IZO layer;

[0099] 3) Spin coating a 20 nm PEDOT:PSS layer on the product obtained in step 3) at a spin coating speed of 6000 rpm for 40 seconds. After the spin coating is completed, the product is placed on a hot plate for annealing at 150° C. for 20 minutes to obtain a hole transport layer with a thickness of 20 nm;

[0100] 4) 1 mmol of stannous iodide, iodomethane, and 5 mmol% of stannous fluoride were dissolved in a DMF / DMSO mixed solvent to prepare a FASnI3 solution with a concentration of 1.57 mmol / mL;

[0101] 1mmol of lead iodide, iodomethylamine, and 3.5mmol of lead thiocyanate were dissolved in a DMF / DMSO mixed solvent to prepare a 1.57mmol / mL MAPbI3 solution;

[0102] FASnI3 solution and MAPbI3 solution were mixed in a ratio of 6:4 and stirred at room temperature to obtain a clear and transparent (FASnI3) 0.6 (MAPbI3)0.4 Narrow bandgap perovskite precursors;

[0103] 5) The product of step 3) is transferred to a glove box filled with N2 for deposition of perovskite film.

[0104] 80μL (FASnI3) 0.6 (MAPbI3) 0.4 The narrow bandgap perovskite precursor solution was spin-coated on the PEDOT:PSS layer at 1000 rpm for 10 seconds and 4000 rpm for 60 seconds. 700 μL of ether was added during the spin-coating process. After the spin-coating, the film was annealed at 65°C for 3 minutes and then at 100°C for 7 minutes to obtain the perovskite film.

[0105] Ethylenediamine iodine powder was dissolved in IPA solution to obtain a back passivation solution with a concentration of 1 mg / mL. 80 μL of the back passivation solution was dropped onto the perovskite film and spin-coated at 4000 rpm for 20 seconds. The film was then immediately annealed at 100°C for 5 minutes to form a narrow-bandgap perovskite absorber layer.

[0106] 6) The product obtained in step 5) was placed in a thermal evaporation chamber at 4×10 -4 Pa in a high vacuum and evaporate 20 nm of C 60 The material is used as the electron transport layer, 6 nm of BCP is evaporated as the hole blocking layer, and 100 nm of copper is evaporated as the metal electrode layer to obtain the 2-CNA modified stacked perovskite solar cell of this embodiment.

[0107] The performance of the laminated perovskite solar cell prepared in this embodiment was measured, and the results were as follows: Figure 10 As shown, it can be seen that the device has excellent performance, with a photoelectric conversion efficiency of 28.09% and an open circuit voltage of 2.155V.

[0108] In summary, the present invention uses p-OHPEAI ​​for the first time to be incorporated into a wide-bandgap perovskite precursor solution. p-OHPEAI ​​will be adsorbed in parallel on the perovskite lattice surface, changing the vertical adsorption configuration of traditional PEAI, thereby inhibiting the formation of a two-dimensional phase. In addition, when the perovskite light-absorbing layer contacts the electron transport layer, the polar structure at both ends of p-OHPEAI ​​will form a dipole layer at the interface, further promoting energy level matching, enhancing interface connection, and improving carrier transport capacity. Based on this mechanism, introducing other functional groups or adjusting the position of substituents on the basis of traditional PEAI cannot achieve the effect of the present invention, because the hydroxyl group can only make the additive adsorbed in parallel on the perovskite surface in the corresponding position, thereby eliminating the two-dimensional phase. Applying the wide-bandgap perovskite prepared by the present invention to stacked batteries can improve the opening voltage and efficiency of stacked devices and enhance stability.

[0109] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for preparing a wide-bandgap perovskite film based on interface engineering regulation, characterized in that: include, 4-Hydroxyphenethylammonium iodide dissolved in FA 0.8 Cs 0.2 Pb(I 0.6 Br 0.4 )3 to obtain a wide bandgap perovskite precursor solution from the precursor solution; The wide band gap perovskite precursor solution is spin-coated on the substrate in two steps and then annealed in two steps to obtain a wide band gap perovskite film.

2. The method for preparing a wide-bandgap perovskite film based on interface engineering control according to claim 1, characterized in that: The doping concentration of 4-hydroxyphenethylammonium iodide in the wide bandgap perovskite precursor solution is 0.5 to 2 mol %.

3. The method for preparing a wide bandgap perovskite film based on interface engineering control according to claim 1, characterized in that: The first step of the two-step spin coating has a spin coating speed of 450-500 rpm and a time of 1-2 s; the second step of the spin coating has a spin coating speed of 4000-5000 rpm and a time of 60-65 s.

4. The method for preparing a wide-bandgap perovskite film based on interface engineering control according to claim 3, characterized in that: At 20-22 seconds of the second spin coating step, ether was added dropwise as an anti-solvent.

5. The method for preparing a wide bandgap perovskite film based on interface engineering control according to claim 4, characterized in that: The amount of ether added to the wide bandgap perovskite precursor solution is 70-80:8-9 (μL).

6. The method for preparing a wide bandgap perovskite film based on interface engineering control according to claim 1, characterized in that: The first step of the two-step annealing is annealing at 65° C. for 1.5 to 2 minutes, and the second step is annealing at 95 to 100° C. for 9.5 to 10 minutes.

7. The wide bandgap perovskite thin film material prepared by the preparation method according to any one of claims 1 to 6.

8. Use of the wide bandgap perovskite thin film material according to claim 7 in the preparation of wide bandgap perovskite solar cells.

9. A wide bandgap perovskite solar cell, characterized in that: The structure from bottom to top includes: ITO substrate layer, thickness of 0.6-0.8 mm, made of ITO conductive glass; Self-assembled molecular layer, thickness 0.1-1.5 nm, material 4PADCB; A wide bandgap perovskite light-absorbing layer having a thickness of 400 to 500 nm, the material of which is the wide bandgap perovskite thin film material according to claim 7; Electron transport layer, thickness is 10~30nm, material is C 60 ; A hole blocking layer with a thickness of 6 to 8 nm or 10 to 20 nm, made of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline or atomic layer deposited SnO2; The metal electrode layer has a thickness of 100 to 200 nm and is made of silver or copper.

10. A laminated wide bandgap perovskite solar cell, characterized in that: The structure from bottom to top includes: ITO substrate layer, thickness of 0.6-0.8 mm, made of ITO conductive glass; Self-assembled molecular layer, thickness 0.1-1.5 nm, material 4PADCB; A wide bandgap perovskite light-absorbing layer having a thickness of 400 to 500 nm, the material of which is the wide bandgap perovskite thin film material according to claim 7; Electron transport layer, thickness is 10~30nm, material is C 60 ; The intermediate connection layer has a thickness of 80 to 90 nm and is made of SnO2 and IZO, wherein the thickness of SnO2 is 15 to 20 nm and the thickness of IZO is 65 to 70 nm; Hole transport layer, thickness 20-25 nm, made of PEDOT:PSS; Narrow bandgap perovskite absorption layer, thickness 800 ~ 900nm, material (FASnI3) 0.6 (MAPbI3) 0.4 ; Electron transport layer, thickness is 10~30nm, material is C 60 ; A hole blocking layer with a thickness of 6 to 8 nm or 10 to 20 nm, made of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline or atomic layer deposited SnO2; The metal electrode layer has a thickness of 100 to 200 nm and is made of silver or copper.

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