A method for preparing and applying a dual heterojunction passivated perovskite solar cell interface.

Abstract

This invention provides a method for preparing and applying a double heterojunction passivated perovskite solar cell interface, relating to the field of perovskite solar cell technology. The method for preparing the perovskite solar cell interface involves modifying a TiO2 thin film transport layer with metal ion doping, preparing a SnO2 thin film on top of this film, and then spin-coating an oxyacid anion layer onto the SnO2 film surface to form a TiO2 / SnO2 / oxyacid anion double heterojunction electron transport layer; or directly adding oxyacid anions to a SnO2 solution to form a TiO2 / SnO2@oxyacid anion double heterojunction electron transport layer. This double heterojunction electron transport layer is applied to the fabrication of perovskite solar devices, superimposed with an interface layer to passivate the interface between the perovskite and the electron transport layer, reduce interface defects, and decrease non-radiative recombination of charge carriers at the interface, thereby improving the efficiency and stability of the perovskite solar cell and enhancing the transport capability of the electron transport layer.

Description

Technical Field

[0001] This invention belongs to the field of perovskite battery technology, specifically relating to a method for preparing and applying a double heterojunction passivated perovskite battery interface. Background Technology

[0002] Photovoltaic power generation, as a renewable energy source, has become one of the important directions for new energy development in various countries. Photovoltaic technology has evolved from first-generation silicon solar cells and second-generation gallium arsenide thin films to today's organic compound solar cells, dye-sensitized solar cells (DSSC), perovskite cells, and other new types of solar cells.

[0003] Perovskite solar cells, belonging to the third generation of emerging solar cells, have become a research hotspot in the photovoltaic industry and academia due to their advantages such as low cost, abundant raw material sources, and high power conversion efficiency. Despite these advantages, perovskite solar cells still face many unresolved issues. For example, perovskite exhibits instability under conditions of heat, oxygen, ultraviolet light, and water. Furthermore, carrier recombination caused by interfacial energy level mismatch and interface defects reduces the efficiency and stability of the cell, a significant reason for the reduced efficiency. These obstacles hindering the improvement of perovskite solar cell efficiency are among the major challenges facing the further high-efficiency production and application of perovskite solar cells.

[0004] Currently, there is an urgent need to develop a series of interface optimization schemes to passivate interface defects, adjust the interface band arrangement, and regulate perovskite crystallization to manage interface charge carriers. Chinese invention patent CN113611802A discloses a perovskite solar cell modified with organic small molecules, its preparation method, and its application. In this invention, the electron transport layer is a TiO2 or SnO2 thin film, and organic small molecule modifiers with an R1-CH=CHCOO-R2 structure, such as methyl acrylate or methyl methacrylate, are used. The modifiers are combined with ionic liquids to modify halide perovskites, improving their photoelectric properties, increasing the efficiency from 20% before modification to 22.4%.

[0005] Chinese invention patent CN115513383A discloses a method for stabilizing the perovskite / electron transport layer interface through the synergistic effect of functional groups and its application in solar cells. The method involves adding an interface-modifying molecule between the perovskite light-absorbing layer and the electron transport layer. This molecule contains potassium cations (K+) and organic anions, wherein the organic anion contains both sulfonyl and fluorine functional groups to stabilize the interface between the perovskite light-absorbing layer and the electron transport layer. The interface-modifying molecule is any one of potassium bis(trifluorosulfonyl)imide, potassium bis(fluorosulfonyl)imide, potassium methanesulfonate, or potassium chloride. This interface optimization scheme effectively passivates functional layers and interface defects, regulates the crystallization of lead iodide and the perovskite thin film, and improves the efficiency and stability of the battery. Its power conversion efficiency is increased from 21.2% to 23.21%.

[0006] Through continuous research, doping-modified transport layers have proven to be an effective strategy for obtaining high-quality, stable perovskite devices. Furthermore, introducing an additional energy level gradient layer between the transport layer and the perovskite absorber layer is a novel and effective way to modulate carrier transport in perovskites. However, relying solely on passivation often fails to achieve optimal passivation performance. Introducing another gradient transport layer to passivate the perovskite, based on a doped transport layer, will achieve a win-win performance outcome.

[0007] In view of this, the present invention utilizes metal ion doping to modify the TiO2 thin film transport layer, and prepares a SnO2 thin film on this basis. A layer of oxyacid anion is spin-coated on the surface of the SnO2 thin film to form a TiO2 / SnO2 / oxyacid anion double heterojunction electron transport layer to passivate the interface between the perovskite and the electron transport layer, thereby improving the transport capability of the electron transport layer, reducing carrier recombination at the interface, and improving the efficiency of the battery. Summary of the Invention

[0008] This invention addresses the problems existing in the prior art by providing a method for preparing and applying a dual heterojunction passivated perovskite solar cell interface. The method involves modifying a TiO2 thin film transport layer using metal ion doping, preparing a SnO2 thin film on top of this layer, and then spin-coating an oxyacid anion layer onto the SnO2 film surface to form a TiO2 / SnO2 / oxyacid anion dual heterojunction electron transport layer. This dual heterojunction electron transport layer is then applied to the fabrication of perovskite solar devices, where the superimposed interface layer further passesivates the interface between the perovskite and the electron transport layer, thereby enhancing the electron transport capability of the electron transport layer.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0010] First, this invention provides a method for preparing a dual heterojunction passivated perovskite solar cell interface, comprising the following steps:

[0011] (1) Metal ion-TiO2 thin film was obtained by low-temperature deposition of metal ion-doped TiCl4 solution followed by high-temperature calcination at 400-600℃ for 30-90 min.

[0012] (2) SnO2 solution was spin-coated onto the surface of a metal ion-TiO2 film and calcined at 120-180℃ for 20-50 min to prepare a SnO2 film.

[0013] (3.1) A layer of oxyacid anion is spin-coated on the surface of SnO2 film and calcined at low temperature of 100-150℃ for 10-30 min to form TiO2 / SnO2 / oxyacid anion double heterojunction electron transport layer.

[0014] (3.2) Or in step (2), the oxyacid anion is directly added to the SnO2 solution and calcined at a low temperature of 100-180℃ for 20-50 min to form a TiO2 / SnO2@oxyacid anion double heterojunction electron transport layer.

[0015] (4) A perovskite absorption layer and a hole transport layer are spin-coated on the double heterojunction electron transport layer to prepare a double heterojunction passivated perovskite solar cell film.

[0016] Preferably, in step (1), the metal ion is selected from Ba. 2+ Ce 2+ Ru 2+ Cu 2+ At least one of them, the concentration of the metal ion is 0.1-10 mg / mL.

[0017] Preferably, in step (1), the salt of the metal ion is selected from at least one of BaCl2, CeCl2, RuCl2, and CuCl2.

[0018] Preferably, in step (1), the concentration of the TiCl4 solution is 20-30 mM.

[0019] More preferably, the concentration of the TiCl4 solution is 25 mM.

[0020] Preferably, in step (1), the temperature of the low-temperature deposition is 60-80℃, and the temperature is maintained for 30-90 minutes.

[0021] More preferably, the low-temperature deposition temperature is 70°C, and the holding time is 60 minutes.

[0022] Preferably, in step (1), the high-temperature calcination temperature is 500°C and the calcination time is 60 minutes.

[0023] Preferably, in step (2), the concentration of the SnO2 solution is 1-3 wt%.

[0024] Preferably, in step (2), the spin coating speed is 3500-6000 r / s.

[0025] Preferably, in step (2), the low-temperature calcination temperature is 150°C and the calcination time is 30 minutes.

[0026] Preferably, in steps (3.1) and (3.2), the oxyacid anion is selected from ClO4. - NO3 - SO4 2- CrO4 2- CO3 2- PO4 3- PO4 2- MoO4 2- VO4 3- SiO3 2- At least one of them.

[0027] More preferably, the solution containing oxyacid anions is selected from ClO4. - NO3 - SO4 2- CrO4 2- CO3 2- PO4 3- PO4 2- MoO4 2- VO4 3- SiO3 2- At least one of the sodium salts.

[0028] Preferably, in steps (3.1) and (3.2), the spin coating speed is 3500-6000 r / s.

[0029] Preferably, in step (3.1), the concentration of the oxyacid anion is 0.001-2.0 mol / L.

[0030] Preferably, in step (3.1), the low-temperature calcination temperature is 120°C and the calcination time is 20 min.

[0031] Preferably, in step (3.2), the low-temperature calcination temperature is 150°C and the calcination time is 30 min.

[0032] Preferably, in step (3.2), @ represents SnO2 being modified by oxyacid ions, and the concentration of the oxyacid anion added to the SnO2 solution is 0.001-0.7 mol / L.

[0033] Preferably, in step (4), the perovskite absorber layer is an ABX3 perovskite absorber layer thin film material, wherein A is selected from at least one of Cs+ and Rb+, and B is selected from Pb. 2+ Sn 2+ Or Ge 2+ At least one of them, X is selected from Br - I - Cl - At least two of them.

[0034] More preferably, the titanium dioxide absorber layer is a CsPbI2Br perovskite absorber layer thin film material.

[0035] More preferably, the method for preparing the perovskite absorber layer includes the following steps:

[0036] S1. Preparation of ABX3 perovskite precursor solution: Dissolve AX and BX2 in dimethyl sulfoxide and stir for 10-15 h to obtain ABX3 perovskite precursor solution.

[0037] S2. Spin coating and calcination: Spin-coat the ABX3 perovskite precursor solution onto the double heterojunction electron transport layer, and calcine at a low temperature of 150-180℃ for 10-30 min to form a perovskite absorber layer film.

[0038] More preferably, the concentration of the ABX3 perovskite precursor solution is 1.0-1.5 mol / L.

[0039] More preferably, in step S2, the spin coating speed is 2000-4000 r / s.

[0040] More preferably, in step S2, the low-temperature calcination temperature is 160°C and the calcination time is 20 minutes.

[0041] Preferably, in step (4), the material of the hole transport layer is selected from at least one of polythiophene, polysilane, triphenylmethane, triarylamine, hydrazone, pyrazoline, chezolium, carbazole, and butadiene.

[0042] More preferably, the hole transport layer is made of poly-3-hexylthiophene (P3HT).

[0043] Then, the present invention provides a perovskite solar cell, wherein the perovskite solar cell forms an interface between a passivated perovskite and a double heterojunction electron transport layer by the above-described preparation method.

[0044] In this invention, the perovskite solar cell is assembled from a conductive substrate layer, a double heterojunction electron transport layer, a perovskite absorber layer, a hole transport layer, and an electrode layer.

[0045] Preferably, the material of the conductive substrate layer is selected from at least one of FTO conductive glass and ITO conductive glass.

[0046] Preferably, the dual heterojunction electron transport layer is a TiO2 / SnO2 / oxyacid anion dual heterojunction electron transport layer or a TiO2 / SnO2@oxyacid anion dual heterojunction electron transport layer.

[0047] Preferably, the method for preparing the double heterojunction electron transport layer includes the following steps:

[0048] (1) Metal ion-TiO2 thin film was obtained by low-temperature deposition of metal ion-doped TiCl4 solution followed by high-temperature calcination at 400-600℃ for 30-90 min.

[0049] (2) SnO2 solution was spin-coated onto the surface of a metal ion-TiO2 film and calcined at 120-180℃ for 20-50 min to prepare a SnO2 film.

[0050] (3.1) A layer of oxyacid anion is spin-coated on the surface of SnO2 film and calcined at low temperature of 100-150℃ for 10-30 min to form TiO2 / SnO2 / oxyacid anion double heterojunction electron transport layer.

[0051] (3.2) Or in step (2), the oxyacid anion is directly added to the SnO2 solution and calcined at a low temperature of 100-180℃ for 20-50 min to form a TiO2 / SnO2@oxyacid anion double heterojunction electron transport layer.

[0052] More preferably, the method for preparing the double heterojunction electron transport layer includes the following steps:

[0053] (1) Metal ion-TiO2 thin film was obtained by using a 20-30mM TiCl4 solution doped with metal ions, depositing at a low temperature of 60-80℃ for 30-90min, and calcining at a high temperature of 500℃ for 60min.

[0054] (2) A SnO2 solution was spin-coated onto the surface of a metal ion-TiO2 thin film. The SnO2 solution had a concentration of 1-3 wt%. The film was then calcined at 150 °C for 30 min to obtain a SnO2 thin film.

[0055] (3.1) A layer of oxyacid anion is spin-coated on the surface of SnO2 film at 3500-6000r / s. The concentration of oxyacid anion is 0.001-2.0mol / L. After calcination at 120℃ for 20min, a TiO2 / SnO2 / oxyacid anion double heterojunction electron transport layer is formed.

[0056] (3.2) Or in step (2), oxyacid anions are directly added to SnO2 solution, the concentration of oxyacid anions added to SnO2 solution is 0.001-0.7mol / L, and calcined at 150℃ for 30min to form TiO2 / SnO2@oxyacid anion double heterojunction electron transport layer;

[0057] More preferably, in step (1), the metal ion is selected from Ba. 2+ Ce 2+ Ru 2+ Cu 2+ At least one of them, the concentration of the metal ion is 0.1-10 mg / mL.

[0058] More preferably, in steps (3.1) and (3.2), the oxyacid anion is selected from ClO4. - NO3 - SO4 2- CrO4 2- CO3 2- PO4 3- PO4 2- MoO4 2- VO4 3- SiO3 2- At least one of them.

[0059] Preferably, the perovskite absorber layer is an ABX3 perovskite absorber layer thin film material, wherein A is selected from at least one of Cs+ and Rb+, and B is selected from Pb. 2+ Sn 2+ Or Ge 2+ At least one of them, X is selected from Br - I - Cl - At least two of them.

[0060] More preferably, the titanium dioxide absorber layer is a CsPbI2Br perovskite absorber layer thin film material.

[0061] More preferably, the method for preparing the perovskite absorber layer includes the following steps:

[0062] S1. Preparation of ABX3 perovskite precursor solution: Dissolve AX and BX2 in dimethyl sulfoxide and stir for 10-15 h to obtain ABX3 perovskite precursor solution.

[0063] S2. Spin coating and calcination: Spin-coat the ABX3 perovskite precursor solution onto the double heterojunction electron transport layer, and calcine at a low temperature of 150-180℃ for 10-30 min to form a perovskite absorber layer film.

[0064] More preferably, the concentration of the ABX3 perovskite precursor solution is 1.0-1.5 mol / L.

[0065] More preferably, in step S2, the spin coating speed is 2000-4000 r / s.

[0066] More preferably, in step S2, the low-temperature calcination temperature is 160°C and the calcination time is 20 minutes.

[0067] Preferably, in step (4), the material of the hole transport layer is selected from at least one of polythiophene, polysilane, triphenylmethane, triarylamine, hydrazone, pyrazoline, chezolium, carbazole, and butadiene.

[0068] More preferably, the hole transport layer is made of poly-3-hexylthiophene (P3HT).

[0069] Preferably, the electrode layer material is selected from at least one of Ag, Au, and Cu.

[0070] Finally, this invention provides the application of the above-mentioned method for preparing the interface of a double heterojunction passivated perovskite solar cell in the preparation of perovskite solar cells.

[0071] Preferably, in the application, the cells are assembled into complete cells using standard perovskite solar cell assembly processes.

[0072] Compared with the prior art, the present invention has the following beneficial effects:

[0073] (1) The double heterojunction electron transport layer prepared by the preparation method of the present invention passivates the interface of the perovskite battery. Its passivation effect on the interface defects of the thin film is higher than that of a single electron transport layer, which greatly improves the electron transport capability of a single electron transport layer, thereby reducing the carrier recombination probability at the interface of the perovskite device and achieving a synergistic win-win objective.

[0074] (2) In the preparation method of the present invention, the double heterojunction electron transport layer uses metal ions and oxyanions to synergistically enhance the transport layer, which not only modifies and optimizes the transport layer, but also modifies the surface and interface of the perovskite absorber layer, reduces the vacancy defects on the surface of the perovskite absorber layer, reduces the non-radiative recombination of the perovskite absorber layer, and achieves the effect of synergistic passivation of the perovskite surface and interface.

[0075] (3) The metal ions and oxyacid anions used in this invention are numerous and have simple sources; the passivation effect of the double heterojunction is presented in various ways. The oxyacid anions can not only be spin-coated on the surface of the perovskite film for interface passivation, but can also be directly added to the SnO2 electron transport layer aqueous solution to prepare TiO2 / SnO2@oxyacid anion double heterojunction electron transport layer, so as to achieve the same effect of co-passivating the interface of the perovskite film in different ways. Attached Figure Description

[0076] Figure 1 This is a SEM image of the perovskite solar cell thin film prepared in Example 1 of this invention;

[0077] Figure 2 This is a SEM image of the perovskite solar cell thin film prepared in Comparative Example 1 of this invention;

[0078] Figure 3 This is a SEM image of the perovskite solar cell thin film prepared in Comparative Example 2 of this invention;

[0079] Figure 4 This is a SEM image of the perovskite solar cell thin film prepared in Comparative Example 3 of this invention. Detailed Implementation

[0080] The following non-limiting embodiments are intended to enable those skilled in the art to gain a more comprehensive understanding of the present invention, but do not limit the invention in any way. The following content is merely an exemplary description of the scope of protection claimed in this application. Those skilled in the art can make various changes and modifications to the invention based on the disclosed content, and such changes should also fall within the scope of protection claimed in this application.

[0081] The “range” disclosed in this document takes the form of a lower limit and an upper limit. It can be one or more lower limits and one or more upper limits, respectively. A given range is defined by selecting a lower limit and an upper limit. The selected lower and upper limits define the boundaries of the particular range. All ranges that can be defined in this way are inclusive and composable; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is also expected that ranges of 60-110 and 80-120 are also expected. Furthermore, if the minimum range values ​​are listed as 1 and 2, and if the maximum ranges are listed as 3, 4, and 5, then the following ranges are all expected: 1-2, 1-4, 1-5, 2-3, 2-4, and 2-5.

[0082] In this invention, unless otherwise specified, the numerical range "ab" represents a shortened representation of any combination of real numbers from a to b, where a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" have been listed in this document, and "0-5" is simply a shortened representation of these numerical combinations.

[0083] In this invention, unless otherwise specified, all embodiments and preferred embodiments mentioned herein can be combined to form new technical solutions.

[0084] In this invention, unless otherwise specified, all the technical features and preferred features mentioned herein can be combined to form new technical solutions.

[0085] The present invention will be further described below by way of specific embodiments. Unless otherwise specified, all chemical reagents used in the embodiments of the present invention are obtained through conventional commercial means.

[0086] Example 1

[0087] (1) Preparation of CeCl2-doped TiO2 thin film: FTO conductive glass (fluorine-doped SnO2 transparent conductive glass) was immersed in a TiCl4 solution containing 1 mg / ml CeCl2 (concentration of 25 mM) and kept at 70℃ for 60 min. Then, the residual TiCl4 solution on the FTO surface was rinsed with deionized water and anhydrous ethanol, dried, and then calcined in a muffle furnace at 500℃ for 60 min. After natural cooling, a dense CeCl2-doped TiO2 (Ce-TiO2) thin film was formed.

[0088] (2) Preparation of Ce-TiO2 / SnO2 film: Take 40 μL of SnO2 aqueous solution with SnO2 concentration of 3 wt% and spin-coat it onto the Ce-TiO2 film at a speed of 5000 r / s. Then, calcine it at a low temperature of 150 °C for 30 min to form Ce-TiO2 / SnO2 film.

[0089] (3)Ce-TiO2 / SnO2 / PO4 2- Thin film preparation: 40 μL of sodium phosphate dodecahydrate aqueous solution (concentration 0.38 mol / L) was spin-coated onto the Ce-TiO2 / SnO2 thin film at a speed of 5000 r / s. The film was then calcined at 120 °C for 20 min to form Ce-TiO2 / SnO2 / PO4. 2- film.

[0090] (4) Preparation of perovskite solar cell thin films and devices: Weigh 272 mg of cesium iodide, 187 mg of lead bromide, and 235.5 mg of lead iodide powder and dissolve them in 1 mL of dimethyl sulfoxide solvent. Then stir at room temperature for 12 hours to form a perovskite CsPbI2Br solution. Subsequently, take 30-50 μL of the above perovskite CsPbI2Br solution and spin-coat it onto Ce-TiO2 / SnO2 / PO4. 2- On a thin film substrate, heating at 160℃ for 20 min forms the corresponding perovskite absorber layer. After cooling, a poly-3-hexylthiophene (P3HT) hole layer (15 mg / ml chlorobenzene solution) is spin-coated, followed by the deposition of an 80 nm thick silver electrode, assembling the perovskite solar cell. The prepared perovskite solar cell is then tested using a solar simulator at 100 mW / cm². -2 The photoelectric conversion efficiency was tested under standard light illumination. The effective area of ​​the cell was 0.0625 cm². 2 .

[0091] Figure 1 This is the perovskite battery film prepared in Example 1.

[0092] Example 2

[0093] Unlike Example 1, the metal ions used in step (1) are different; the metal ion solution used is 0.8 mg / ml BaCl2. Step (1) specifically involves:

[0094] (1) Preparation of BaCl2-doped TiO2 thin film: FTO conductive glass (fluorine-doped SnO2 transparent conductive glass) was immersed in a TiCl4 solution containing 0.8 mg / ml BaCl2 (concentration of 25 mM) and kept at 70℃ for 60 min. Then, the residual TiCl4 solution on the FTO surface was rinsed with deionized water and anhydrous ethanol, dried, and then calcined in a muffle furnace at 500℃ for 60 min. After natural cooling, a dense BaCl2-doped TiO2 (Ba-TiO2) thin film was formed.

[0095] The methods for steps (2)-(4) are as described in Example 1.

[0096] Example 3

[0097] Unlike Example 1, in step (3), the oxyacid anion is replaced with ClO4. - Specifically:

[0098] (3)Ce-TiO2 / SnO2 / ClO4 -Thin film preparation: 40 μL of sodium perchlorate aqueous solution (concentration 0.6 mol / L) was spin-coated onto the Ce-TiO2 / SnO2 thin film at a speed of 5000 r / s. The film was then calcined at 120 °C for 20 min to form Ce-TiO2 / SnO2 / ClO4. - film.

[0099] The methods for steps (1)-(2) and (4) are as described in Example 1.

[0100] Example 4

[0101] (1) Preparation of CeCl2-doped TiO2 thin film: FTO conductive glass (fluorine-doped SnO2 transparent conductive glass) was immersed in a TiCl4 solution containing 1 mg / ml CeCl2 (concentration of 25 mM) and kept at 70℃ for 60 min. Then, the residual TiCl4 solution on the FTO surface was rinsed with deionized water and anhydrous ethanol, dried, and then calcined in a muffle furnace at 500℃ for 60 min. After natural cooling, a dense CeCl2-doped TiO2 (Ce-TiO2) thin film was formed.

[0102] (2)Ce-TiO2 / SnO2 / PO4 2- Thin film preparation: Sodium phosphate dodecahydrate was mixed with a 3 wt% SnO2 aqueous solution. 40 μL of the mixture was spin-coated onto the Ce-TiO2 film at a speed of 5000 r / s. The film was then calcined at 150 °C for 30 min to form Ce-TiO2 / SnO2 / PO4. 2- A thin film was added to an aqueous solution of SnO2 with an oxyacid anion concentration of 0.5 mol / L.

[0103] (3) The perovskite cell film and device were prepared in the same way as in Example 1 and assembled into the corresponding perovskite solar cell.

[0104] Comparative Example 1

[0105] Unlike Example 1, no metal ions were doped in step (1). Step (1) specifically involves:

[0106] (1) Preparation of TiO2 film: FTO conductive glass was immersed in a TiCl4 solution with a concentration of 25 mM and kept at 70℃ for 60 min. Then, the residual TiCl4 solution on the FTO surface was rinsed with deionized water and anhydrous ethanol, dried, and placed in a muffle furnace for calcination at 500℃ for 60 min. After natural cooling, a dense TiO2 film was formed.

[0107] The methods for steps (2)-(4) are as described in Example 1.

[0108] Figure 2 This is a SEM image of the battery thin film prepared in Comparative Example 1.

[0109] Comparative Example 2

[0110] Unlike Example 1, step (3) of spin-coating oxyacid anions was not performed. Specifically:

[0111] (1) Preparation of CeCl2-doped TiO2 thin film: FTO conductive glass was immersed in a TiCl4 solution containing 1 mg / ml CeCl2 (concentration of 25 mM) and kept at 70 °C for 60 min. Then, the residual TiCl4 solution on the FTO surface was rinsed with deionized water and anhydrous ethanol, dried, and then calcined in a muffle furnace at 500 °C for 60 min. After natural cooling, a dense CeCl2-doped TiO2 (Ce-TiO2) thin film was formed.

[0112] (2) Preparation of Ce-TiO2 / SnO2 thin film: Take 40 μL of SnO2 aqueous solution with a concentration of 3 wt%, spin-coat it onto the Ce-TiO2 thin film at a speed of 5000 r / s, and calcine it at a low temperature of 150 °C for 30 min to form Ce-TiO2 / SnO2 thin film.

[0113] (3) Preparation of perovskite solar cell thin film and device: Weigh 272 mg of cesium iodide, 187 mg of lead bromide, and 235.5 mg of lead iodide powder and dissolve them in 1 mL of dimethyl sulfoxide solvent. Then stir at room temperature for 12 hours to form a perovskite CsPbI2Br solution. Subsequently, take 30-50 μL of the above perovskite CsPbI2Br solution and spin-coat it onto a Ce-TiO2 / SnO2 thin film substrate. Heat at 160 °C for 20 min to form the corresponding perovskite absorber layer film. After the film cools, spin-coat a poly-3-hexylthiophene (P3HT) hole layer (15 mg / mL chlorobenzene solution), evaporate a silver electrode (80 nm thick), and assemble the corresponding perovskite solar cell. Figure 3 This is a SEM image of the battery thin film prepared in Comparative Example 2.

[0114] Comparative Example 3

[0115] Unlike Example 1, no metal ions were doped in step (1), and the preparation of oxyacid anions by spin-coating in step (3) was not performed. Specifically:

[0116] (1) Preparation of TiO2 film: FTO conductive glass was immersed in a TiCl4 solution with a concentration of 25 mM and kept at 70℃ for 60 min. Then, the residual TiCl4 solution on the FTO surface was rinsed with deionized water and anhydrous ethanol, dried, and placed in a muffle furnace for calcination at 500℃ for 60 min. After natural cooling, a dense TiO2 film was formed.

[0117] (2) Preparation of TiO2 / SnO2 thin film: Take 40 μL of SnO2 aqueous solution with a concentration of 3 wt%, spin-coat it onto the above TiO2 thin film at a speed of 5000 r / s, and calcine it at a low temperature of 150 °C for 30 min to form TiO2 / SnO2 thin film.

[0118] (3) Preparation of perovskite solar cell thin film and device: Weigh 272 mg of cesium iodide, 187 mg of lead bromide, and 235.5 mg of lead iodide powder and dissolve them in 1 mL of dimethyl sulfoxide solvent. Then stir at room temperature for 12 hours to form a perovskite CsPbI2Br solution. Subsequently, take 30-50 μL of the above perovskite CsPbI2Br solution and spin-coat it onto a TiO2 / SnO2 thin film substrate. Heat at 160 °C for 20 min to form the corresponding perovskite absorber layer film. After the film cools, spin-coat a poly-3-hexylthiophene (P3HT) hole layer (15 mg / mL chlorobenzene solution), evaporate a silver electrode (80 nm thick), and assemble it into the corresponding perovskite solar cell.

[0119] Figure 4 This is a SEM image of the battery thin film prepared in Comparative Example 3.

[0120] Comparative Example 4

[0121] Unlike Example 1, in step (3), the sodium dodecahydrate aqueous solution is replaced with a potassium difluorosulfonamide solution with a concentration of 0.38 mol / L.

[0122] The remaining steps and parameters are as described in Example 1.

[0123] Comparative Example 5

[0124] Unlike Example 1, step (1) did not involve the preparation of a TiO2 thin film. Instead, a metal ion salt solution was doped into an aqueous SnO2 solution, specifically:

[0125] (1) FTO conductive glass was immersed in an aqueous solution of SnO2 containing 1 mg / ml CeCl2 with a SnO2 concentration of 3 wt%, and kept at 70 °C for 60 min. Then, the residual SnO2 on the FTO surface was rinsed with deionized water and anhydrous ethanol, and calcined at 150 °C for 30 min to form a Ce-SnO2 film.

[0126] The remaining steps are as described in Example 1.

[0127] Comparative Example 6

[0128] Unlike Example 1, the SnO2 film coating in step (2) was not performed. Instead, an oxyacid anion solution was spin-coated directly onto a dense CeCl2-doped TiO2 (Ce-TiO2) film.

[0129] The remaining steps are as described in Example 1.

[0130] The perovskite solar cells prepared in Examples 1-4 and Comparative Examples 1-6 were tested using a solar simulator at 100 mW / cm². -2 The photoelectric conversion efficiency was tested under standard light irradiation. The test results are shown in Table 1.

[0131] Table 1

[0132]

[0133] As shown in Table 1, compared with the comparative example, modifying both the TiO2 electron transport layer and the interface layer in the examples further improves the photoelectric conversion efficiency of the battery device. Furthermore, changes in the modification method and parameters affect the photoelectric conversion efficiency. The method for preparing the dual heterojunction electron transport layer and the dual heterojunction passivated perovskite battery interface of this invention improves the performance of the transport layer itself while simultaneously regulating the interface layer, achieving synergistic and optimal passivation.

[0134] The battery films prepared in Example 1 and Comparative Examples 1-3 were subjected to SEM detection. The SEM images are shown below. Figure 1-4 .

[0135] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing a dual heterojunction passivated perovskite solar cell interface, characterized in that, Including the following steps: (1) Metal ion-TiO2 thin film was obtained by low-temperature deposition of metal ion-doped TiCl4 solution followed by high-temperature calcination at 400-600℃ for 30-90 min. (2) SnO2 solution was spin-coated onto the surface of a metal ion-TiO2 film and calcined at 120-180℃ for 20-50 min to prepare a SnO2 film. (3.1) A layer of oxyacid anion is spin-coated on the surface of SnO2 film and calcined at low temperature of 100-150℃ for 10-30 min to form TiO2 / SnO2 / oxyacid anion double heterojunction electron transport layer. (3.2) Or in step (2), the oxyacid anion is directly added to the SnO2 solution and calcined at a low temperature of 100-180℃ for 20-50 min to form a TiO2 / SnO2@oxyacid anion double heterojunction electron transport layer. (4) A perovskite absorption layer and a hole transport layer are spin-coated on the double heterojunction electron transport layer to prepare a double heterojunction passivated perovskite solar cell film.

2. The preparation method according to claim 1, characterized in that, In step (1), the metal ion is selected from at least one of Ba 2+ , Ce 2+ , Ru 2+ , Cu 2+ , and the concentration of the metal ion is 0.1-10 mg / mL.

3. The preparation method according to claim 1, characterized in that, In step (1), the temperature of the low-temperature deposition is 60-80℃, and the temperature is maintained for 30-90 minutes.

4. The preparation method according to claim 1, characterized in that, In step (2), the concentration of the SnO2 solution is 1-3 wt%; the spin coating speed is 3500-6000 r / s.

5. The preparation method according to claim 1, characterized in that, In steps (3.1) and (3.2), the oxyacid anion is selected from ClO4. - NO3 - SO4 2- CrO4 2- CO3 2- PO4 3- PO4 2- MoO4 2- VO4 3- SiO3 2- At least one of the following; the spin coating speed is 3500-6000 r / s.

6. The preparation method according to claim 1, characterized in that, In step (3.1), the concentration of the oxyacid anion is 0.001-2.0 mol / L; in step (3.2), the concentration of the oxyacid anion added to the SnO2 solution is 0.001-0.7 mol / L.

7. The preparation method according to claim 1, characterized in that, In step (4), the perovskite absorber layer is an ABX3 perovskite absorber layer thin film material, wherein A is selected from at least one of Cs+ and Rb+, and B is selected from Pb. 2+ Sn 2+ Or Ge 2+ At least one of them, X is selected from Br - I - Cl - At least two of the following are selected: The perovskite absorber layer is obtained by the following preparation method: S1, preparing ABX3 perovskite precursor solution: dissolving AX and BX2 in dimethyl sulfoxide and stirring for 10-15 h to obtain ABX3 perovskite precursor solution; S2, spin coating and calcination: spin coating the ABX3 perovskite precursor solution onto the double heterojunction electron transport layer, and calcining at a low temperature of 150-180℃ for 10-30 min to form a perovskite absorber layer film; The hole transport layer material is selected from at least one of polythiophene, polysilane, triphenylmethane, triarylamine, hydrazone, pyrazoline, chezolium, carbazole, and butadiene.

8. A perovskite solar cell prepared by the preparation method according to any one of claims 1-7.

9. The perovskite solar cell according to claim 8, characterized in that, The method for preparing the double heterojunction electron transport layer includes the following steps: (1) Metal ion-TiO2 thin film was obtained by low-temperature deposition of metal ion-doped TiCl4 solution followed by high-temperature calcination at 400-600℃ for 30-90 min. (2) SnO2 solution was spin-coated onto the surface of a metal ion-TiO2 film and calcined at 120-180℃ for 20-50 min to prepare a SnO2 film. (3.1) A layer of oxyacid anion is spin-coated on the surface of SnO2 film and calcined at low temperature of 100-150℃ for 10-30 min to form TiO2 / SnO2 / oxyacid anion double heterojunction electron transport layer. (3.2) Or in step (2), the oxyacid anion is directly added to the SnO2 solution and calcined at a low temperature of 100-180℃ for 20-50 min to form a TiO2 / SnO2@oxyacid anion double heterojunction electron transport layer.

10. The application of the preparation method according to any one of claims 1-7 in the preparation of perovskite solar cells.

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