Perovskite solar cell and preparation method thereof

Abstract

The invention discloses a perovskite solar cell and a preparation method thereof, and belongs to the technical field of perovskite solar cells. According to the invention, the passivation material and the electron transport material are mixed to obtain the mixed precursor, and the mixed precursor is coated on the surface of the substrate to obtain the passivation / electron composite layer, so that the high sensitivity of an ultrathin passivation layer to the thickness is avoided; the process problem that carrier transmission is hindered due to the fact that the thickness is difficult to be accurately controlled below the nanoscale is solved, in addition, passivation materials in the composite layer reduce perovskite surface defects, the self-aggregation tendency of the electron transmission materials is restrained by changing the molecule accumulation mode of the electron transmission materials, and therefore the more uniform and compact electron transmission thin film is obtained, and the performance of the electron transmission thin film is improved. Interface contact and carrier transmission are optimized; moreover, according to the preparation method disclosed by the invention, the traditional two-step preparation process is simplified into one step, so that the production efficiency is remarkably improved, and convenience is provided for low-cost and large-area manufacturing.

Description

Technical Field

[0001] This invention relates to the field of perovskite solar cell technology, and in particular to a perovskite solar cell and its fabrication method. Background Technology

[0002] Perovskite polycrystalline thin films obtained through solution processing undergo rapid crystallization and high-temperature annealing, resulting in various defects in the bulk phase, grain boundaries, and surface. Among these defects are uncoordinated lead ions (Pb). 2+ Due to their low formation energy, these defects are one of the main defects. The presence of these defects not only leads to nonradiative recombination losses, reducing open-circuit voltage and fill factor, but also becomes a weak point for induced degradation by moisture, oxygen, etc., impairing device stability.

[0003] Depositing an ultrathin passivation layer on a perovskite surface to reduce surface defects is an effective method. However, these passivation materials often have low electrical conductivity, and while increasing the thickness can enhance the passivation effect, it can also hinder carrier transport. Under current technological conditions, the thickness of these ultrathin passivation layers must be precisely controlled within a few nanometers to ensure that carriers can be transported through thickness-sensitive mechanisms such as tunneling. This high sensitivity to thickness is clearly detrimental to low-cost, large-area production. Summary of the Invention

[0004] The main objective of this invention is to provide a perovskite solar cell and its preparation method, thereby solving the technical problem that the passivation layer is highly sensitive to thickness, making it difficult to control the thickness and thus difficult to balance the passivation effect and carrier transport.

[0005] To achieve the above objectives, the present invention provides a method for preparing a perovskite solar cell, comprising the following steps: preparing a passivation / electron composite layer: mixing a passivation material and an electron transport material to obtain a mixed precursor, and coating the mixed precursor onto the surface of a substrate to obtain the passivation / electron composite layer.

[0006] In some embodiments of the present invention, the passivation material includes at least one of the following functional groups: -NH2, -NH 3+ -OH, -COO - .

[0007] In some embodiments of the present invention, the passivation material includes at least one of a polymer and an ammonium salt small molecule, wherein the polymer includes at least one of polymethyl methacrylate and polyethylene glycol; and the ammonium salt small molecule includes at least one of propylenediamine iodide, ethylenediamine hydroiodate, and diammonium 1,4-phenyliodide.

[0008] In some embodiments of the present invention, the electron transport material includes at least one of fullerene derivatives, naphthalene diimide-based polymers (NDI), perylene diimide (PDI) polymers, cyano-functionalized bisthiophene diimide dimer-based polymers, and PCNI2-BTI.

[0009] In some embodiments of the present invention, the passivating material is dissolved in a first solvent to obtain a passivating material solution, the electron transport material is dissolved in a second solvent to obtain an electron transport material solution, and the passivating material solution and the electron transport material solution are mixed to obtain the mixed precursor.

[0010] In some embodiments of the present invention, the first solvent includes at least one of chlorobenzene, toluene or o-dichlorobenzene, and isopropanol; And / or, the second solvent includes chlorobenzene; And / or, the concentration of the passivating material solution is 0.1 mg / ml to 2 mg / ml; And / or, the concentration of the electron transport material solution is 10 mg / ml to 20 mg / ml; And / or, the volume ratio of the electron transport material solution to the passivation material solution is 15:50-15:150.

[0011] In some embodiments of the present invention, the preparation method includes the following steps: preparing a hole transport layer, preparing a perovskite active layer, preparing the passivation / electron composite layer, preparing an electron blocking layer, and preparing a back electrode layer; Alternatively, the preparation method includes the following steps: preparing a hole transport layer, preparing a SAM layer, preparing a perovskite active layer, preparing the passivation / electron composite layer, preparing an electron blocking layer, and preparing a back electrode layer; Alternatively, the preparation method includes the following steps: preparing a hole transport layer, preparing a perovskite active layer, preparing an interface modification layer, preparing the passivation / electron composite layer, preparing an electron blocking layer, and preparing a back electrode layer; Alternatively, the preparation method may include the following steps: preparing a hole transport layer, preparing a SAM layer, preparing a perovskite active layer, preparing an interface modification layer, preparing the passivation / electron composite layer, preparing an electron blocking layer, and preparing a back electrode layer.

[0012] In some embodiments of the present invention, the preparation method includes preparing the interface modification layer, the interface modification layer including an interface modification material, the interface modification material including at least one of LiF and MgF2.

[0013] In some embodiments of the present invention, the preparation method further includes P1 etching, P2 etching, and P3 etching.

[0014] The present invention also provides a perovskite solar cell, which is prepared by the perovskite solar cell preparation method described above.

[0015] In some embodiments of the present invention, the perovskite solar cell includes a conductive glass, a hole transport layer, a perovskite active layer, a passivation / electron recombination layer, an electron blocking layer, and a back electrode layer stacked sequentially. Alternatively, the perovskite solar cell may include, in sequence, a conductive glass, a hole transport layer, a SAM layer, a perovskite active layer, the passivation / electron recombination layer, an electron blocking layer, and a back electrode layer. Alternatively, the perovskite solar cell may include, in sequence, a conductive glass, a hole transport layer, a perovskite active layer, an interface modification layer, the passivation / electron recombination layer, an electron blocking layer, and a back electrode layer. Alternatively, the perovskite solar cell may comprise, in sequence, a conductive glass, a hole transport layer, a SAM layer, a perovskite active layer, an interface modification layer, the passivation / electron recombination layer, an electron blocking layer, and a back electrode layer.

[0016] The beneficial effects that this invention can achieve are: This invention integrates a passivation layer and an electron transport layer into a composite functional layer. First, it effectively avoids the high sensitivity of ultrathin passivation layers to thickness, solving the process problem of hindering carrier transport due to the difficulty in precisely controlling the thickness below the nanometer level. Second, the passivation material in the composite layer reduces perovskite surface defects and suppresses the self-aggregation tendency of the electron transport material by changing its molecular stacking mode, thereby obtaining a more uniform and dense electron transport film and optimizing interfacial contact and carrier transport. Finally, the preparation method of this invention simplifies the traditional two-step preparation process into one step, significantly improving production efficiency and providing convenience for low-cost, large-area manufacturing. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of a perovskite solar cell according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a perovskite solar cell according to another embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of a perovskite solar cell according to another embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of a perovskite solar cell according to another embodiment of the present invention; Figure 5 These are AFM characterization diagrams of Embodiment 1 and Comparative Example 1 of the present invention. The left diagram is Comparative Example 1, and the right diagram is Embodiment 1. Figure 6 This is a comparison chart of the stability of perovskite solar cells in Example 1 and Comparative Example 1 of the present invention.

[0019] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Attached image description: 100. Perovskite solar cell; 10. Conductive glass; 20. Hole transport layer; 30. SAM layer; 40. Perovskite active layer; 50. Interface modification layer; 60. Passivation / electron recombination layer; 70. Electron blocking layer; 80. Back electrode layer. Detailed Implementation

[0021] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0023] In this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Furthermore, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. If the combination of technical solutions is contradictory or impossible to implement, such a combination should be considered non-existent and not within the scope of protection claimed by this invention.

[0024] Depositing an ultrathin passivation layer on a perovskite surface to reduce surface defects is an effective method. However, these passivation materials often have low electrical conductivity, and while increasing the thickness can enhance the passivation effect, it can also hinder carrier transport. Under current technological conditions, the thickness of these ultrathin passivation layers must be precisely controlled within a few nanometers to ensure that carriers can be transported through thickness-sensitive mechanisms such as tunneling. This high sensitivity to thickness is clearly detrimental to low-cost, large-area production.

[0025] In view of this, the present invention provides a perovskite solar cell and a method for preparing the same. The preparation method includes the following steps: preparing a passivation / electron composite layer: mixing a passivation material and an electron transport material to obtain a mixed precursor, and coating the mixed precursor onto the surface of a substrate to obtain a passivation / electron composite layer.

[0026] It is understandable that passivation materials refer to a class of functional materials that reduce surface defects in other functional layers of optoelectronic devices, such as perovskite active layers, through physical covering or chemical action.

[0027] It is understandable that electron transport materials refer to a class of functional materials with specific energy level structures and electronic properties. Their main function is to efficiently and selectively receive (extract) and transport electrons in optoelectronic devices, while blocking the passage of holes (positive charges).

[0028] It is understandable that a passivation / electron composite layer refers to a composite film prepared by mixing passivation materials and electron transport materials, which can perform the functions of both a passivation layer and an electron transport layer.

[0029] This invention integrates a passivation layer and an electron transport layer into a composite functional layer. First, it effectively avoids the high sensitivity of ultrathin passivation layers to thickness, solving the process problem of hindering carrier transport due to the difficulty in precisely controlling the thickness below the nanometer level. Second, the passivation material in the composite layer reduces perovskite surface defects and suppresses the self-aggregation tendency of the electron transport material by changing its molecular stacking mode, thereby obtaining a more uniform and dense electron transport film and optimizing interfacial contact and carrier transport. Finally, the preparation method of this invention simplifies the traditional two-step preparation process into one step, significantly improving production efficiency and providing convenience for low-cost, large-area manufacturing.

[0030] In some embodiments, the passivating material includes at least one of the following functional groups: -NH2, -NH 3+ -OH, -COO - In this embodiment, the passivation material contains -NH2 and -NH... 3+ -OH, -COO - Functional groups can interact with uncoordinated Pb on the perovskite surface2+ Direct bonding enables chemical passivation, significantly reducing interface defect density. This passivation function is co-blended with the electron transport function, eliminating the need for stringent control of the passivation layer thickness in traditional layering processes. One-step film formation can simultaneously suppress the self-aggregation of electron transport materials, reduce film roughness, and improve carrier extraction efficiency, thereby simultaneously improving the Voc, FF, and PCE of perovskite devices. Moreover, the air stability of the passivation / electron composite layer is superior to that of the layered structure of the passivation / electron transport layer.

[0031] In some embodiments, the passivating material includes at least one of polymers and ammonium salt small molecules.

[0032] In some embodiments, the polymer includes at least one of polymethyl methacrylate (PMMA) and polyethylene glycol (PEG).

[0033] In some embodiments, the ammonium salt small molecules include at least one of propylenediamine iodide (PDAI2), ethylenediamine hydroiodate (EDAI2), and diammonium 1,4-benzenediodide (BDAI2).

[0034] In some embodiments, the electron transport material includes at least one of fullerene derivatives (PCBM), naphthalene diimide (NDI) polymers, perylene diimide (PDI) polymers, cyano-functionalized bisthiophene diimide dimer polymers, and PCNI2-BTI. These electron transport materials can synergistically form films with blended passivation materials. This allows for efficient electron extraction by leveraging the high electron affinity of the electron transport materials, while the passivation materials suppress the self-aggregation of the electron transport materials, significantly reducing film roughness and improving the efficiency and stability of perovskite devices.

[0035] In some embodiments, a passivating material is dissolved in a first solvent to obtain a passivating material solution, and an electron transport material is dissolved in a second solvent to obtain an electron transport material solution. The passivating material solution and the electron transport material solution are then mixed to obtain a mixed precursor. By dissolving the passivating material and the electron transport material separately in solvents and then mixing them, a uniform blend film can be formed in a single coating step. This simplifies the process, eliminates limitations on the passivation layer thickness, and simultaneously achieves chemical passivation and electron transport, significantly reducing interface defects and improving electron transport efficiency.

[0036] In some embodiments, the first solvent includes at least one of chlorobenzene, toluene, or o-dichlorobenzene and isopropanol.

[0037] In some embodiments, the second solvent comprises chlorobenzene.

[0038] In some embodiments, the concentration of the passivation material solution is 0.1 mg / ml to 2 mg / ml, and may be 0.1 mg / ml, 0.5 mg / ml, 1 mg / ml, 1.5 mg / ml, 2 mg / ml, etc.

[0039] In some embodiments, the concentration of the electron transport material solution is 10 mg / ml to 20 mg / ml.

[0040] In some embodiments, the volume ratio of the electron transport material solution to the passivation material solution is 15:50 to 15:150, and can be 15:50, 15:60, 15:70, 15:80, 15:90, 15:100, 15:110, 15:120, 15:130, 15:140, 15:150, etc.

[0041] In some embodiments, the fabrication method of a perovskite solar cell includes the following steps: fabricating a hole transport layer, fabricating a perovskite active layer, fabricating a passivation / electron recombination layer, fabricating an electron blocking layer, and fabricating a back electrode layer. In this embodiment, a hole transport layer is fabricated on the surface of a conductive glass, a perovskite active layer is fabricated on the surface of the hole transport layer away from the conductive glass, a conductive glass / hole transport layer / perovskite active layer is used as a substrate, a passivation / electron recombination layer is fabricated on the surface of the perovskite active layer away from the hole transport layer, an electron blocking layer is fabricated on the surface of the passivation / electron recombination layer away from the perovskite active layer, and a back electrode layer is fabricated on the surface of the electron blocking layer away from the passivation / electron recombination layer.

[0042] In some embodiments, the fabrication method of a perovskite solar cell includes the following steps: fabricating a hole transport layer, fabricating a SAM layer, fabricating a perovskite active layer, fabricating a passivation / electron recombination layer, fabricating an electron blocking layer, and fabricating a back electrode layer. In this embodiment, a hole transport layer is fabricated on the surface of a conductive glass, a SAM layer is fabricated on the surface of the hole transport layer away from the conductive glass, a perovskite active layer is fabricated on the surface of the SAM layer away from the hole transport layer, using the conductive glass / hole transport layer / SAM layer / perovskite active layer as a substrate, a passivation / electron recombination layer is fabricated on the surface of the perovskite active layer away from the SAM layer, an electron blocking layer is fabricated on the surface of the passivation / electron recombination layer away from the perovskite active layer, and a back electrode layer is fabricated on the surface of the electron blocking layer away from the passivation / electron recombination layer.

[0043] In some embodiments, the fabrication method of a perovskite solar cell includes the following steps: fabricating a hole transport layer, fabricating a perovskite active layer, fabricating an interface modification layer, fabricating a passivation / electron recombination layer, fabricating an electron blocking layer, and fabricating a back electrode layer. In this embodiment, a hole transport layer is fabricated on the surface of a conductive glass, a perovskite active layer is fabricated on the surface of the hole transport layer away from the conductive glass, an interface modification layer is fabricated on the surface of the perovskite active layer away from the hole transport layer, using the conductive glass / hole transport layer / perovskite active layer / interface modification layer as a substrate, a passivation / electron recombination layer is fabricated on the surface of the interface modification layer away from the perovskite active layer, an electron blocking layer is fabricated on the surface of the passivation / electron recombination layer away from the interface modification layer, and a back electrode layer is fabricated on the surface of the electron blocking layer away from the passivation / electron recombination layer.

[0044] In some embodiments, the fabrication method of a perovskite solar cell includes the following steps: fabricating a hole transport layer, fabricating a SAM layer, fabricating a perovskite active layer, fabricating an interface modification layer, fabricating a passivation / electron recombination layer, fabricating an electron blocking layer, and fabricating a back electrode layer. In this embodiment, a hole transport layer is fabricated on the surface of a conductive glass; a SAM layer is fabricated on the surface of the hole transport layer facing away from the conductive glass; a perovskite active layer is fabricated on the surface of the SAM layer facing away from the hole transport layer; an interface modification layer is fabricated on the surface of the perovskite active layer facing away from the SAM layer; using the conductive glass / hole transport layer / SAM layer / perovskite active layer / interface modification layer as a substrate, a passivation / electron recombination layer is fabricated on the surface of the interface modification layer away from the perovskite active layer; an electron blocking layer is fabricated on the surface of the passivation / electron recombination layer away from the interface modification layer; and a back electrode layer is fabricated on the surface of the electron blocking layer away from the passivation / electron recombination layer.

[0045] In some embodiments, the conductive glass includes transparent conductive oxide glass (TCO).

[0046] In some embodiments, the transparent conductive oxide glass includes at least one of FTO and ITO.

[0047] In some embodiments, the conductive glass is cleaned during the step of preparing the conductive glass.

[0048] In some embodiments, the hole transport layer includes a hole transport material, which includes nickel oxide.

[0049] In some embodiments, the thickness of the hole transport layer is 13nm~18nm, which can be 13nm, 14nm, 15nm, 16nm, 17nm, or 18nm.

[0050] In some embodiments, the method for preparing the hole transport layer includes magnetron sputtering, deposition, etc.

[0051] In some embodiments, the method for preparing the hole transport layer is magnetron sputtering. The radio frequency power supply used in the magnetron sputtering method is 800W~1200W, or 1000W. The argon / oxygen flow ratio of the magnetron sputtering method is (400sccm~500sccm):(100sccm~150sccm). The magnetron sputtering time is 8min~12min, or 10min.

[0052] In some embodiments, the hole transport layer is prepared by magnetron sputtering, the target material for magnetron sputtering is nickel oxide, and the nickel oxide target is cleaned for 5 min to 6 min using an RF power supply of 1500W to 1800W.

[0053] In this invention, the SAM layer refers to a functional layer prepared using self-assembled small molecules (SAMs), which plays a role in interfacial energy level regulation and hole selective transport, thereby improving hole extraction efficiency, reducing interfacial barriers, and improving the film quality of the upper perovskite layer.

[0054] In some embodiments, the self-assembled small molecules include one or more of the following: [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (Me-4PACz), [2-(9H-carbazole-9-yl)ethyl]phosphonic acid (2PACz), [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (MeO-2PACz), [4-(9H-9'-phenyl-3,3'-dibicarbazole-9-yl)butyl]phosphonic acid (4PABCz), Poly-4PACz, Poly-2PACz, etc.

[0055] In some embodiments, a self-assembled small molecule is dissolved in a solvent to obtain a SAM precursor, and the SAM precursor is coated onto the surface of a hole transport layer to obtain a SAM layer.

[0056] In some embodiments, the concentration of the SAM precursor is 0.21 mg / mL to 1 mg / mL.

[0057] In some embodiments, the method for preparing the SAM layer includes a coating method, which includes slot coating.

[0058] In some embodiments, the SAM layer is prepared by slit coating, in which a self-assembled small molecule solution is injected into the coating head, the coating speed is 15 mm / s to 25 mm / s (or 20 mm / s), and the injection speed is 25 μL / s to 35 μL / s (or 30 μL / s).

[0059] In some embodiments, in the step of preparing the SAM layer, after the self-assembled small molecule solution is coated onto the surface, it is annealed at a temperature of 100°C for a time of 10 min.

[0060] In some embodiments, the substrate includes a perovskite active layer, and a passivation / electron composite layer is prepared on the surface of the perovskite active layer. The passivation / electron composite layer is formed by a single film deposition on the surface of the perovskite active layer, simultaneously completing defect passivation and electron extraction, reducing interfacial recombination, and improving open-circuit voltage and fill factor. This eliminates the need for sensitive control of sub-nanometer thickness in traditional layering processes, simplifies the process, reduces costs, and suppresses the self-aggregation of electron transport material PCBM. The film surface is more uniform, and device efficiency and air stability are improved simultaneously, making it suitable for large-area mass production.

[0061] In some embodiments, the perovskite active layer comprises a perovskite material, the general formula of which is ABX. 3 Where: A includes FA + MA + Cs + One or more of them; B-site includes Pb 2+ ;X bits include I - ,Br - Cl - One or more of them.

[0062] In some embodiments, perovskite materials include Cs 0.05 FA 0.95 PbI3.

[0063] In some embodiments, the substrate includes a perovskite active layer and an interface modification layer stacked sequentially, and a passivation / electron composite layer is prepared on the surface of the interface modification layer facing away from the perovskite active layer.

[0064] In some embodiments, the interface modification layer includes at least one of LiF and MgF2. The LiF and MgF2 in the interface modification layer can first induce lattice expansion and n-type doping in the perovskite active layer, forming a field passivation depletion region and enhancing the electron extraction driving force. Then, a passivation / electron recombination layer is blended onto this layer, achieving integrated chemical passivation and electron transport. The two layers synergistically further reduce interfacial recombination, simultaneously increasing the open-circuit voltage and fill factor. Furthermore, the process has a large tolerance for thickness, balancing high efficiency and large-area fabrication.

[0065] In some embodiments, the preparation process of the interface modification layer includes the following steps: depositing an interface modification material on the surface of the perovskite active layer to obtain the interface modification layer.

[0066] In some embodiments, an interface modification layer is obtained by depositing an interface modification material on the surface of a perovskite active layer using a vacuum evaporation method.

[0067] In some embodiments, the evaporation rate of the vacuum evaporation method is 0.3 Å / s to 0.6 Å / s, and may be 0.5 Å / s.

[0068] In some embodiments, the thickness of the interface modification layer is 0.5 nm to 1 nm.

[0069] In this invention, the electron blocking layer serves to prevent electrons (negative charges) from moving from one region to another, while allowing holes (positive charges) to pass through smoothly.

[0070] In some embodiments, the electron blocking layer comprises an electron blocking material, which includes SnO2.

[0071] In some embodiments, the method for preparing the electron blocking layer includes atomic layer deposition (ALD) or plasma deposition (RPD).

[0072] In some embodiments, the back electrode layer includes a back electrode material, which includes at least one of Ag, Cu, and Au.

[0073] In some embodiments, the method for preparing the back electrode layer includes thermal evaporation.

[0074] In some embodiments, the thickness of the back electrode layer is 90nm~110nm, and can be 100nm.

[0075] In some embodiments, the fabrication method further includes P1 etching, P2 etching, and P3 etching to obtain a series structure for the perovskite solar cell.

[0076] In this invention, P1 etching is performed on conductive glass to etch the conductive layer of the conductive glass.

[0077] In this invention, P2 etching is performed after the functional layer is deposited. The functional layer is etched to expose the conductive glass. The functional layer includes a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, and may also include a SAM layer and an electron blocking layer.

[0078] In this invention, P3 etching is performed after the back electrode layer is deposited, and the back electrode layer is etched to expose the aforementioned functional layer.

[0079] In some embodiments, reference Figure 1 The perovskite solar cell 100 includes a conductive glass 10, a hole transport layer 20, a perovskite active layer 40, a passivation / electron recombination layer 60, an electron blocking layer 70, and a back electrode layer 80, which are stacked sequentially.

[0080] In some embodiments, reference Figure 2 The perovskite solar cell 100 consists of a conductive glass 10, a hole transport layer 20, a SAM layer 30, a perovskite active layer 40, a passivation / electron composite layer 60, an electron blocking layer 70, and a back electrode layer 80, which are stacked sequentially. In some embodiments, reference Figure 3 The perovskite solar cell 100 includes a conductive glass 10, a hole transport layer 20, a perovskite active layer 40, an interface modification layer 50, a passivation / electron recombination layer 60, an electron blocking layer 70, and a back electrode layer 80, which are stacked sequentially. In some embodiments, reference Figure 4 The titanium dioxide solar cell 100 includes a conductive glass 10, a hole transport layer 20, a SAM layer 30, a perovskite active layer 40, an interface modification layer 50, a passivation / electron recombination layer 60, an electron blocking layer 70, and a back electrode layer 80, which are stacked sequentially.

[0081] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following specific embodiments are only used to explain the present invention and are not intended to limit the present invention.

[0082] Example 1 Example 1: The fabrication method of perovskite solar cells is as follows: P1 etching: A 30cm×30cm conductive FTO is patterned and etched. The etching depth is enough to remove the conductive layer, the line width is 30μm, and the width between different etch lines is 6.5mm.

[0083] Cleaning of conductive glass: The patterned conductive glass FTO is ultrasonically cleaned for 15 minutes each with cleaning agent, deionized water and 75% ethanol solvent, then dried with nitrogen gun, and finally treated with ultraviolet ozone for 10 minutes, and then set aside.

[0084] Preparation of hole transport layer: The nickel oxide target was washed with a 1700W radio frequency (RF) power supply for 5 minutes, and then sputtered with a 1000W power at an argon / oxygen ratio of 400sccm:100sccm for 10 minutes to obtain a dense nickel oxide film with a thickness of 15nm, thus obtaining the hole transport layer.

[0085] Preparation of the SAM layer: 50 mg of Me-4PACz was dissolved in 50 ml of ethanol and stirred at room temperature in a nitrogen glove box until completely dissolved, yielding a 1 mg / ml SAM precursor solution. The SAM precursor solution was injected into the coating head, and coating was performed using a slit coating process. The coating conditions were set as follows: 100 μm pad, 100 μm coating height, 20 mm / s feed rate, and 30 μL / s injection rate. After coating, the SAM layer was annealed at 100 °C for 10 min to obtain the SAM layer.

[0086] Preparation of the perovskite active layer: Prepare a 1.1M C solution. s0.05 FA 0.95The PbI3 perovskite precursor solution was injected into the coating head, and the perovskite was coated using a slit coating process. The coating conditions were set as follows: 80 μm gasket, 100 μm coating height, 30 mm / s travel speed, and 38 μL / s injection speed. After coating, the perovskite was immediately transferred to a flash evaporator and the pressure was reduced from atmospheric pressure to 5 Pa in 10 s and held for 60 s to obtain a bright brown film. The film was then immediately transferred to a hot plate and annealed at 130 °C for 15 min to obtain the perovskite active layer.

[0087] Preparation of interface modification layer: A 1 nm thick LiF layer was deposited on the surface of the perovskite active layer away from the SAM layer by thermal evaporation at a rate of 0.5 Å / s to obtain the interface modification layer.

[0088] Preparation of the passivation / electron composite layer: PDAI2 was used as the passivation material, and PCBM was used as the electron transport material. PDAI2 and PCBM were dissolved in isopropanol (IPA) and chlorobenzene (CB), respectively, at concentrations of 0.5 mg / mL and 20 mg / mL. The two solutions were then mixed at a volume ratio of 15:100 to obtain a mixed precursor. The mixed precursor was injected into a coating head, and coating was performed using a slit coating process. The coating conditions were set as follows: 100 μm pad, 100 μm coating height, 10 mm / s feed rate, and 8 μL / s injection rate. After coating, the layer was annealed at 100 °C for 10 min to obtain the passivation / electron composite layer.

[0089] Preparation of the electron blocking layer: A 15 nm thick SnO2 film was grown on the surface of the passivation / electron composite layer away from the interface modification layer using spatial atomic layer deposition (ALD). The flow rate of tetra(dimethylamino)tin (TDMASn) was 450 sccm, the flow rate of H2O was 65 sccm, the substrate temperature was preheated to 110 °C for 2 h to ensure a constant and uniform chamber temperature, and the SnO2 electron blocking layer was obtained after 10 min of deposition.

[0090] P2 etching: In order to connect different sub-cells in series, the FTO / hole transport layer / SAM layer / perovskite active layer / interface modification layer / passivation / electron recombination layer / electron blocking layer are P2 etched. The P2 etching depth does not damage the FTO layer, the line width is 60μm, and the line spacing between P1 and P2 is 80μm.

[0091] Preparation of the back electrode layer: The back electrode layer was prepared by thermal evaporation on the surface of the SnO2 buffer layer away from the passivation / electron composite layer under high vacuum (1×10⁻⁶). -5 An Ag back electrode layer with a thickness of 100 nm was deposited under Pa conditions.

[0092] P3 etching: Nanosecond green light is used to etch the FTO / hole transport layer / SAM layer / perovskite active layer / interface modification layer / passivation / electron recombination layer / electron blocking layer / back electrode layer without damaging the FTO, thus completing the separation of the top electrode. The P3 linewidth is 30μm, and the line spacing between P2 and P3 is 80μm, thereby completing the fabrication of the perovskite device.

[0093] The devices in the embodiments are all inverted structure components with the following structure: FTO / hole transport layer / SAM layer / perovskite active layer / interface modification layer / passivation / electron recombination layer / electron blocking layer / back electrode layer.

[0094] Example 2 Example 2 describes the fabrication of perovskite solar cells using the same method as in Example 1, with the following differences: (1) The size of FTO is 2.45cm×2.45cm, and the process does not include P1 etching, P2 etching and P3 etching, which is a small area battery; (2) Preparation of SAM layer: The SAM layer was prepared by spin coating. 60 μL of SAM precursor solution was dropped onto the surface of the hole transport layer. The spin coating speed was 3000 rpm and the spin coating time was 30 s. Then, it was annealed at 100℃ for 10 minutes to form a thin SAM molecular layer. (3) Preparation of perovskite active layer: Under nitrogen protection (this step is carried out in a glove box with water and oxygen content both less than 0.1 ppm), Cs with a concentration of 1.5 M is spin-coated. 0.05 FA 0.95 PbI3 perovskite yellow precursor solution, 60 μL was dropped onto the surface of the SAM layer, and spin-coated at a low speed of 1000 rpm and a high speed of 5000 rpm, respectively, with spin-coating times of 5 s and 30 s. Chlorobenzene solvent was added dropwise in the 5th second before the end of the high-speed stage. After spin-coating was completed, the perovskite active layer was obtained by annealing at 120℃ for 15 min. (4) Passivation / electronic composite layer: The passivation / electronic composite layer was prepared by spin coating. The mixed precursor was spin coated onto the surface of the interface modification layer at 2000 rpm for 45 s to obtain the passivation / electronic composite layer.

[0095] Example 3 Example 3 prepared a perovskite solar cell according to the preparation method of Example 1, except that no interface modification layer was prepared.

[0096] Example 4 Example 4 describes the preparation of a perovskite solar cell using the same method as in Example 1, except that the passivation material in Example 4 is polymethyl methacrylate (PMMA).

[0097] Example 5 Example 5 describes the preparation of a perovskite solar cell using the same method as in Example 1, except that the passivation material in Example 5 is polyethylene glycol (PEG).

[0098] Comparative Example 1 Comparative Example 1 prepared a perovskite solar cell according to the method of Example 1, except for the step of preparing the passivation / electron composite layer. Comparative Example 1 used a stepwise continuous deposition method to prepare the second passivation layer and the electron transport layer separately. The coating parameters of PDAI2 were: 100 μm pad, 100 μm coating height, 15 mm / s travel speed, and 5 μL / s liquid injection rate. After coating, PCBM was coated. The coating parameters of PCBM were: 100 μm pad, 100 μm coating height, 10 mm / s travel speed, and 8 μL / s liquid injection rate. After coating, it was annealed at 100°C for 10 min.

[0099] Comparative Example 2 Comparative Example 2 prepared a perovskite solar cell according to the method of Example 2, except for the step of preparing the passivation / electron composite layer. Comparative Example 2 used a distributed continuous deposition method to prepare the passivation layer and the electron transport layer respectively. The deposition method of PDAI2 was to spin-coat 0.5 mg / ml IPA solution on the perovskite film at 3000 r for 30 s. PCBM was to spin-coat 0.5 mg / ml CB solution at 2000 r for 45 s immediately after PDAI2.

[0100] Performance testing 1. The passivation / electron composite layer of Example 1 and the passivation / electron transport layer of Comparative Example 1 were observed using an atomic force microscope, and the results were obtained. Figure 5 , Figure 5 The left-middle figure is a representation of Comparative Example 1. Figure 5 The right-hand figure is a characterization diagram of Example 1, from... Figure 5 As can be seen, Rq=24.5nm in the left figure and Rq=17.8nm in the right figure, indicating that the roughness of the passivation / electron composite layer in Example 1 is reduced compared to the passivation / electron transport layer in Comparative Example 1. This is beneficial for enhancing interfacial contact and improving the photoelectric conversion efficiency of perovskite devices.

[0101] 2. The stability of the perovskite devices in Example 1 and Comparative Example 1 was determined, and the results are shown in [Figure Number]. Figure 6 .Depend on Figure 6 It can be seen that the perovskite device in Example 1 has better stability, indicating that the passivation material in the passivation / electron composite layer inhibits the self-aggregation of the electron transport material PCBM, reduces pores, and alleviates the contact of perovskite with water vapor, which is beneficial to improving the stability of the perovskite device. The idea of ​​mixing the passivation material and the electron transport material to prepare the passivation / electron composite layer is feasible.

[0102] 3. Measure the open-circuit voltage (Voc), short-circuit current (Isc), fill factor (FF), and power conversion efficiency (PCE) of the perovskite devices in the examples and comparative examples.

[0103] Open-circuit voltage (Voc) is the output voltage of a solar cell in an open-circuit (i.e., no-load) state.

[0104] The short-circuit current (Isc) refers to the maximum current flowing through a photovoltaic cell or module when the output terminal is short-circuited (i.e., the output terminal is directly connected) under standard test conditions (voltage V = 0).

[0105] The fill factor (FF) is the ratio of the maximum output power (Pmax) of a solar cell to the product of Voc and Isc, and is usually expressed as a percentage of 100%.

[0106] The power conversion efficiency (PCE) of a solar cell refers to the efficiency of converting absorbed light energy into electrical energy. PCE = (Jsc × Voc × FF) / incident light power × 100%. The standard test conditions are as follows: AM1.5 spectrum, incident light power of 1000 W / m², and temperature of 25℃.

[0107] The test data above are detailed in Table 1.

[0108] Table 1

[0109] As shown in Table 1, the embodiments of the present invention, by mixing passivation materials and electron transport materials to prepare a composite passivation / electron composite layer, exhibit improved PCE in both components and small devices.

[0110] Comparing Example 1 and Comparative Example 2, both Comparative Example 1 and Comparative Example 2 used a stepwise method to prepare the passivation layer and electron transport layer, and the performance of the perovskite devices decreased in both cases. This proves that the method of the present invention simplifies the process, effectively improves the performance of perovskite devices, and has a certain degree of versatility when operating on different areas.

[0111] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A method for preparing a perovskite solar cell, characterized by, The method comprises the following steps: Preparation of a passivation / electron complex layer: mixing a passivation material and an electron transport material to obtain a mixed precursor, and coating the mixed precursor onto the surface of a substrate to obtain the passivation / electron complex layer.

2. The method for preparing a perovskite solar cell according to claim 1, characterized in that, The passivation material comprises at least one of the following functional groups: -NH2, -NH 3+ , -OH, -COO - .

3. The method for preparing a perovskite solar cell according to claim 1 or 2, characterized in that, The passivation material comprises at least one of a polymer and an ammonium salt small molecule, wherein the polymer comprises at least one of polymethyl methacrylate and polyethylene glycol; and the ammonium salt small molecule comprises at least one of propylene diamine iodine, ethylenediamine hydroiodide and 1,4-benzenediazonium diiodide. The electron transport material comprises at least one of a fullerene derivative, a naphthalene diimide-based polymer, a perylene diimide polymer, a cyano-functionalized bithiophene imide dimer-based polymer and PCNI2-BTI.

4. The method for preparing a perovskite solar cell according to claim 1, characterized in that, The passivation material is dissolved in a first solvent to obtain a passivation material solution, the electron transport material is dissolved in a second solvent to obtain an electron transport material solution, and the passivation material solution and the electron material solution are mixed to obtain the mixed precursor.

5. The method for preparing a perovskite solar cell according to claim 4, characterized in that, The first solvent comprises at least one of chlorobenzene, toluene, o-dichlorobenzene and isopropyl alcohol. The second solvent comprises chlorobenzene. The concentration of the passivation material solution is 0.1 mg / ml to 2 mg / ml. The concentration of the electron transport material solution is 10 mg / ml to 20 mg / ml. The volume ratio of the electron transport material solution to the passivation material solution is 15:50 to 15:

150.

6. The method of claim 1 to 5, wherein the perovskite solar cell is prepared by the steps of: The preparation method comprises the following steps: preparation of a hole transport layer, preparation of a perovskite active layer, preparation of the passivation / electron complex layer, preparation of an electron blocking layer and preparation of a back electrode layer. The preparation method comprises the following steps: preparation of a hole transport layer, preparation of a SAM layer, preparation of a perovskite active layer, preparation of the passivation / electron complex layer, preparation of an electron blocking layer and preparation of a back electrode layer. The preparation method comprises the following steps: preparation of a hole transport layer, preparation of a perovskite active layer, preparation of an interface modification layer, preparation of the passivation / electron complex layer, preparation of an electron blocking layer and preparation of a back electrode layer. The preparation method comprises the following steps: preparation of a hole transport layer, preparation of a SAM layer, preparation of a perovskite active layer, preparation of an interface modification layer, preparation of the passivation / electron complex layer, preparation of an electron blocking layer and preparation of a back electrode layer.

7. The method for preparing a perovskite solar cell according to claim 6, characterized in that, The preparation method further comprises P1 etching, P2 etching and P3 etching.

8. The method for preparing a perovskite solar cell according to claim 6, characterized in that, The preparation method comprises preparation of the interface modification layer, and the interface modification layer comprises an interface modification material, wherein the interface modification material comprises at least one of LiF and MgF2.

9. A perovskite solar cell, characterized by, The perovskite solar cell is prepared by the preparation method of the perovskite solar cell according to any one of claims 1 to 8.

10. The perovskite solar cell according to claim 9, characterized in that, The perovskite solar cell comprises, in sequence, a conductive glass, a hole transport layer, a perovskite active layer, the passivation / electron complex layer, an electron blocking layer and the back electrode layer. The perovskite solar cell comprises, in sequence, a conductive glass, a hole transport layer, a SAM layer, a perovskite active layer, the passivation / electron complex layer, an electron blocking layer and a back electrode layer. Or, the perovskite solar cell comprises a conductive glass, a hole transport layer, a perovskite active layer, an interface modification layer, the passivation / electron recombination layer, an electron blocking layer, and a back electrode layer which are sequentially stacked. Or, the perovskite solar cell comprises a conductive glass, a hole transport layer, a SAM layer, a perovskite active layer, an interface modification layer, the passivation / electron recombination layer, an electron blocking layer, and a back electrode layer which are sequentially stacked.

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